A novel and useful apparatus for and method of packet detection and carrier frequency offset estimation. The packet detection mechanism is robust to channels and sustains reasonable miss-detect (and false alarm) rates at low SNR values. The mechanism uses a modified combined cross correlation and delay and correlate scheme. A delay and correlate scheme is used in order to handle the effects of multipath while swapping integration and multiplication to increase cross-correlation factors resulting in improved sensitivity in low SNR conditions. Correlation is divided into multiple chains to generate a plurality of partial correlations to observe short patterns in the spread sequence resulting in improved performance in long multipath channels.

The use of packet data transmission and reception is well known in the art. Digital data in the form of a bit stream is assembled into packets, modulated using a modulation scheme and transmitted over a medium (i.e. channel). At the other end of the communications channel, a receiver tries to receive the packet and demodulate the signal back into the original bit stream.
A high level block diagram of a prior art wireless receiver suitable for packet transmission schemes such as WLAN 802.11a/g/n or MBOA-UWB is shown in FIG. 1. The packet receiver, generally referenced 160, comprises an antenna 161, RF demodulator 163, analog to digital converter (ADC) 165, data demodulator 169 and packet detector 167.
In operation, the RF signal 162 is received (picked up) by the antenna 161 and then demodulated by an RF demodulator 163 into a base band or intermediate frequency (IF) signal 164. An analog to digital converter (ADC) 165 translates the analog signal into digital samples 166. The samples are then input to a packet detector 167, which functions to detect when a packet starts and in response provides a synchronization or sync signal 168 to a data demodulator 169. The output of the data demodulator (i.e. modem receiver) 169 translates the digital samples 166 along with the synchronization signal 168 into an output bit stream 170.
Note that the packet receiver 160 highlights the importance of the packet detector 167. The detector 167, however, is an inherently weak link in this scheme because accurate packet detection (which is usually measured by detection and false alarm probabilities) is a necessary but insufficient condition for packet detection. Therefore, if a packet is not detected, the data demodulator 169 will not be able to correctly demodulate the digital samples 166 and generate the packet in output bit stream 170.
Since the wireless medium along with other media types (e.g., cable transmission, optical fiber transmission, etc.) usually consists of noise and other impairments added to the desired signal, it is essential that the packet detector 167 be as robust as possible to the various impairments and be able to accurately provide the sync signal 168 at well below the detection conditions of the data demodulator 169 in order that it does not limit the receiver performance.
A diagram illustrating a typical prior art packet structure and associated synchronization sequence internal structure is shown in FIG. 2. A packet, generally referenced 1205, comprises modulated signals containing a sync sequence field 1201, signaling sequence field 1202 providing information about the packet length, type, priority, etc. and the actual data field (i.e. payload) 1203. The sync sequence is shown expanded into a plurality of sample repetitions. The sync sequence typically comprises periodic or spread spectrum signals comprising M repetitions 1207 of N samples 1206.
For clarity sake we denote the sync sequence 1201 samples as follows. Let b0, b1, . . . , bN−1 denote the basic sequence (i.e. spreading sequence) multiplied by spread sequence a0, a1, . . . , aM−1. The sync sequence 1201 can then be denoted by: a0b0, a0b1, . . . a0bN−1, a1b1b0, a1b1, . . . , a1bN−1, . . . , aM−1b0, aM−1b1, . . . , aM−1bN−1. We also denote cn=a└n/M┘bn mod N as the nth sample in the sequence (nε{0 . . . (N−1)(M−1)}). For brevity we denote K=NM as the length of the entire synchronization sequence 1201.
Two current wireless standards that match this pattern of packet detection are the 802.11a/g standard wherein M=10, N=16 and an=1 and the Multiband OFDM Alliance (MBOA) Ultra Wideband (UWB) standard wherein M=16 and N=8.
Packet detection of an UWB OFDM signal is based on detection of a sequence of preamble symbols. A preamble sequence may be approximated by spreading a 16-bit sequence ('a' sequence) by n 8-bit sequence ('b' sequence). High coding gain of UWB implies a high sensitivity requirement (i.e. below 0 dB SNR), while wide bandwidth and wireless channels implies immunity to the multipath conditions. In addition, in this case symbol based detection is necessary due to possible frequency offset and to lower required circuit area due to avoiding the use of large area memory and minimization of computations.
The 802.11a/g standards operates in 2.4 GHz and 5 GHz bands, respectively, and use 52-subcarrier orthogonal frequency-division multiplexing (OFDM) with a maximum data rate of 54 Mbps. Out of the 52 OFDM subcarriers, 48 are for data and 4 are pilot subcarriers. Each of these subcarriers can have the following modulations: BPSK, QPSK, 16-QAM or 64-QAM. Each of the subcarriers can be represented as a complex number wherein the actual generation and decoding of orthogonal components is performed during baseband processing typically using DSP or other processors which is then upconverted to the RF frequency at the transmitter. The time domain signal is generated by taking an Inverse Fast Fourier transform (IFFT) of the baseband transmit signal. In the receive direction, the receiver downconverts the received samples and performs an FFT to retrieve the original coefficients.
A traditional UWB transmitter works by transmitting pulses across a very wide spectrum of frequency (e.g., typically over a bandwidth of several GHz). At the receiver, the pulses are translated into data by detecting a known pulse sequence (i.e. sync sequence) sent by the transmitter. Modem UWB systems use modulation techniques such as Orthogonal Frequency Division Multiplexing (OFDM) to occupy such wide bandwidths. MultiBand OFDM is capable of dynamically turning off subbands and individual OFDM tones. This provides for good coexistence with narrowband systems such as 802.11a, adaptation to different regulatory environments, future scalability and backward compatibility.
In MultiBand OFDM, the available spectrum of 7.5 GHz is divided into several 528 MHz frequency bands. This allows the selective implementation of bands at certain frequency ranges while leaving other parts of the spectrum unused. The MBOA proposal provides for five logical channels wherein Channel 1, which contains the first three bands, is mandatory for all UWB devices and radios.
OFDM is operative to modulate the information transmitted on each band. OFDM distributes the data over a large number of carriers spaced apart at precise frequencies. This spacing provides the orthogonality, which prevents the demodulators from seeing frequencies other than their own. The benefits of OFDM are high-spectral efficiency, resiliency to RF interference and lower multipath distortion.
Two well known prior art packet detector schemes are shown in FIGS. 3 and 4. A block diagram illustrating a prior art technique for detecting synchronization sequences using cross correlation is shown in FIG. 3. The cross correlation based packet detector, generally referenced 200, comprises a delay line 202 comprising a plurality of delay elements 201, 203, 205, 207, 209, a plurality of multipliers 229, 231, 233, 235, summer 221, absolute value squared 281 and decision logic 223.
In operation, the incoming signal 280 undergoes a delay via delay line 202. The delayed signal samples are multiplied using a plurality of multipliers 229, 231, 233, 235 with the flipped conjugated synchronization sequence samples cK−1*, cK−2*, . . . , c1*, c0* 211, 213, 215, 219. The product results of the multiplications are summed together via summer 221. The total correlation result undergoes absolute value 281 and is compared against a threshold 225 using decision block 223 (e.g., a comparator). If the absolute value correlation value goes above threshold 225 the detection signal 227 becomes active indicating detection of a packet. This method is equivalent in signal processing to a matched filter achieving the best signal to noise ratio under an Additive White Gaussian Noise (AWGN) regime.
A major drawback of the prior art cross correlation scheme is that if the signal has undergone a linear multipath (frequency selective) channel (which is almost always the case in wireless and wire line transmission) then the correlation peaks become distorted and the threshold may sometimes never be crossed resulting in a high miss-detection probability (i.e. false-negatives). Lowering the threshold would result in a corresponding increase in the probability of false alarm (i.e. false-positives), just as problematic. Therefore, this makes this prior art cross correlation detection scheme is not very robust to channels.
Yet another major drawback of this prior art scheme is its lack of tolerance to carrier frequency offset. Since the local oscillator (LO) frequency generation mechanism at the transmitter and receiver are unsynchronized, the resultant signal seen by the receiver at the ADC input is frequency shifted with respect to the ideal IF frequency. This causes the delayed signal samples 280, 272, 273 and 275 to accumulate a phase rotation such that even without the presence of noise or multipath fading there would be a different phase for all correlation results summed via summer 221. This non-coherency causes the absolute value of the correlation peak to drop, thus further degrading the performance of this detector.
A block diagram illustrating a prior art method for detecting a synchronization sequence using a delay and correlate scheme is shown in FIG. 4. The delay and correlate based packet detector circuit, generally referenced 1400, comprises a delay 1401, complex conjugate block 1403, multiplier 1404, absolute value block 1405, low pass filter 1406 and decision logic 1407.
In operation, the incoming signal 1402 undergoes a delay by N using delay circuitry 1401. The original incoming signal 1402 is conjugated and then multiplied with the delayed signal 1410 using multiplier 1404. The result of this multiplication undergoes an absolute value via block 1405 and is then filtered by digital low-pass filter 1406, such as a moving average (MA) or a single order infinite impulse response (IIR) filter. The output of the filter then undergoes a decision process via decision logic 1407 which generates the detection signal 1408. The decision logic may function, for example, by comparing the result to a threshold 1420.
The principle of operation for a delay and correlate packet detector such as that of circuit 1400 is that it uses the periodicity property of the synchronization sequence to verify that the synchronization sequence is actually present at the input. Therefore, multiplying the conjugated signal with its delayed version (where the delay is equal to the synchronization signal period) should yield the absolute value of the signal, since ideally the signal and its delayed version are identical. Furthermore, a linear channel does not change the period of the signal (i.e. its frequency) but only its shape (i.e. the signal undergoes scaling, phase shifts, etc.) and therefore this detector is very robust to channel effects. This scheme is also advantageous due to its resilience to carrier frequency offset. The latter effect causes the delayed signal samples 1410 and the incoming signal samples to have a constant phase difference between them. This constant phase difference is reflected in the input to magnitude block 1405 and is thereby eliminated.
The major drawback of this detector is when white Gaussian noise (AWGN) is added to the signal (which is the case in real world channels). In the case of AWGN added to the signal, the noise samples of the incoming signal and its delayed version are uncorrelated. This causes the noise to be multiplied via multiplier 1404. Although multiplication of uncorrelated noise may be tolerable for high signal to noise ratios (SNRs), it is detrimental for signals with low SNRs where the performance of this detector quickly deteriorates.
It is thus desirable to have a packet detection mechanism that does not suffer from the disadvantages of the prior art cross correlation and delay and correlate based packet detectors. The mechanism should provide packet detection and carrier frequency offset estimation capabilities that are robust to operation in linear channels as well as to transmission signals having low SNRs.

Apparatus for and method of robust packet detection and frequency offset estimation


Washing machines having improved frictional forces with laundry. Those machines include a cabinet with a door, a tub inside for retaining wash water, and an internal vessel, inside the tub that is coupled with a motor that rotates the internal vessel. A friction member inside the internal vessel rubs against laundry. The frictional member includes a friction enhancer, such as a spherical structure or a freely rotating ball, that enhances laundry friction during washing and reduces adhesion of laundry after a dehydration cycle.

1. Field of the Invention
This invention relates to washing machines. More particularly, it relates to washing machines having improved washing performance and easier laundry removal.
2. Discussion of the Related Art
Washing machines operate by revolving a vessel that holds laundry, water, and detergent such that friction, water current, and chemical action clean the laundry. While there are various types of washing machines, common types include drum type washing machines and pulsator type washing machines.
The structure of a typical drum washing machine is schematically illustrated in FIG. 1. As shown, a drum washing machine includes a cabinet 1 having a front door 2, a tub 3 inside the cabinet 1 that retains wash water, and a rotating drum 4 inside the tub 3 that retains laundry. A motor 5 behind the tub 3 is coupled by a driving shaft 6 to the drum 4. Also, a suspension system 7 retains the tub 3 within the cabinet 1 such that the position of the tub 3 can fluctuate slightly.
Still referring to FIG. 1, the driving shaft 6 is coupled to the drum 4 by a spider 8 (which can be tripod-shaped). Additionally, as shown, a number of lifters 10 are mounted on a wall of the drum 4. When the motor 5 rotates the drum 4, the lifters 10 also rotate. Laundry is lifted upward by the lifters 10 until the laundry freely falls down. Continuous rotation causes the laundry to continuously move up and down. Such laundry movement produces a good laundry cleaning action.
FIG. 2 illustrates a typical lifter 10 in more detail. The lifter 10 includes a pair of protrusions 11 that have different heights and that are separated by a valley 12. Coupling hooks 13 at the bottom of the lifter 10 can couple the lifter 10 to the drum 4.
While generally successful, the lifters 10 do not provide optimal washing performance. One reason for this is that the lifters 10 generally have flat (or at least smooth) surfaces that fail to maximize laundry friction. Thus, friction-induced cleaning is limited. Such limited cleaning action occurs not only in drum type washing machines, but also in pulsator type washing machines. The pulsator type cleans both by water flow and by laundry friction. Yet, the widely used pulsator type washing machine also uses generally flat (or at least smooth) contact surfaces. Again, this limits the attainable cleaning action.
While generally successful when cleaning laundry, the lifters 10 become obstacles when removing laundry. Centrifugal forces exerted during a dehydration cycle forces laundry against the wall of the drum 4 and into the valley 12. This causes the laundry to adhere to the drum 4 such that the laundry can be difficult to remove.
A modification to the standard drum type washing machine is the slant-drum washing machine. In such a machine the drum 4 is tilted downward. This reduces the difficulty of inserting and removing laundry. However, in slant-drum 4 washing machines the laundry tends to gather toward the rear of the drum 4 such that the lifters 10 fail to smoothly move the laundry. Thus, cleaning performance is reduced.
Therefore, washing machines having improved washing performance obtained by increasing the friction of lifters with laundry would be beneficial. Also beneficial would be a washing machine having easy laundry removal after dehydration cycles. Also beneficial would be a slant-drum washing machine having a reduced tendency for laundry to congregate at the back of the drum. Even more beneficial would be a drum washing machine with improved laundry friction and ease of laundry removal.


A programmable logic device has many regions of programmable logic, together with relatively general-purpose, programmable, interconnection resources that can be used to make interconnections between virtually any of the logic regions. In addition, various types of more local interconnection resources are associated with each logic region for facilitating the making of interconnections between adjacent or nearby logic regions without the need to use the general-purpose interconnection resources for those interconnections. The local interconnection resources support flexible clustering of logic regions via relatively direct and therefore high-speed interconnections, preferably in both horizontal and vertical directions in the typically two-dimensional array of logic regions. The logic region clustering options provided by the local interconnection resources are preferably boundary-less or substantially boundary-less within the array of logic regions.

This invention relates to programmable logic array integrated circuit devices ("programmable logic devices" or "PLDs"), and more particularly to interconnection resources for use on programmable logic devices that increase the speed at which those devices can be made to operate.
Programmable logic devices typically include (1) many regions of programmable logic, and (2) programmable interconnection resources for selectively conveying signals to, from, and/or between those logic regions. Each logic region is programmable to perform any of several different, relatively simple logic functions. The interconnection resources are programmable to allow the logic regions to work together to perform much more complex logic functions than can be performed by any individual logic region. Examples of known PLDs are shown in Wahlstrom U.S. Pat. No. 3,473,160, Freeman U.S. Pat. No. Re. 34,363, Cliff et al. U.S. Pat. No. 5,689,195, Cliff et al. U.S. Pat. No. 5,909,126, and Jefferson et al. U.S. patent application Ser. No. 09/266,235, all which are hereby incorporated by reference herein.
A frequent objective in the design of PLDs is to increase the speed at which the device can be operated. The speeds at which signals can travel through the interconnection resources between logic regions is particularly important to determining device speed. Overall, the interconnection resources must have the general-purpose capability of connecting any logic region to any other logic region. But in addition to this, it can be helpful to find ways to make faster interconnections between nearby logic regions. Many complex logic tasks can be broken down into parts, each of which can be performed by a respective cluster of logic regions. By providing interconnection resources that facilitate the flexible formation of clusters of logic regions with high-speed interconnection capabilities among the logic regions in such clusters, the ability of the PLD to perform various complex logic tasks at high speed is enhanced.
In view of the foregoing, it is an object of this invention to provide improved interconnection resources for programmable logic devices.
It is a more particular object of this invention to provide interconnection resources for programmable logic devices that facilitate the formation of extended clusters of nearby logic modules between which high-speed interconnections can be made.

Interconnection resources for programmable logic integrated circuit devices


A bushing having an outer sliding surface is produced by a die forming method without machining. A crowning shape is provided to the outer surface so that the outer diameter of the bushing is smaller at its opposite longitudinal ends, and increases progressively toward a central zone of the bushing. A cylindrical bushing blank is fitted on distal end portion of a vertically-movable mandrel. Next, one of an upper die and a lower die is reactively moved toward the other to plastically work the bushing blank by the both dies and the mandrel, thereby working the bushing. An inner diameter of the upper die is larger at its lower end, and decreases progressively away from the lower end, and an inner diameter of the lower die is larger at its upper end, and decreases progressively away from the upper end.

This invention relates to a method of forming or shaping a bearing bushing used in various kinds of machines, such as an automobile, an industrial machine and an agricultural machine, and more particularly to a bushing (whose outer peripheral surface serves as a sliding surface) used in that portion of such a machine which is liable to receive an impact load and an uneven load.
A bushing whose outer peripheral surface is used as a sliding surface is already known. There are known methods of providing a crowning shape to an outer peripheral surface of a bushing so that the outer diameter of the bushing is smaller at its opposite longitudinal ends, and increases progressively toward the longitudinal central zone of the bushing. In one such known method, those portions of an outer peripheral surface of a bushing disposed adjacent to opposite ends thereof are machined to impart a crowning shape to the outer peripheral surface.
For example, a bushing, mounted as a bearing member in a shock absorber provided at a front fork of a motorcycle, receives an impact at the time of start of the motorcycle, and also is greatly influenced by undulations on the road during running of the motorcycle. Namely, due to vibrations transmitted via wheels at the time of the start and during the running, as well as bending of an inner tube (or a shaft) supporting the bushing, and bending of an outer tube slidable relative to the outer peripheral surface of the bushing, an impact load and an uneven load act on the outer peripheral surface (sliding surface) of the bushing at the ends of the bushing. Therefore, it is necessary that this sliding surface of the bushing should be formed into a crowning shape so that the impact load and the uneven load can be absorbed or alleviated.
In the method of providing the crowning shape to the outer peripheral surface of the bushing by machining the time required for the machining is relatively long, and therefore an enhanced productivity can not be expected. And besides, chips produced by machining deposit on the sliding outer peripheral surface of the bushing, and may damage the sliding inner peripheral surface of the outer tube held in sliding contact with the outer sliding surface of the bushing.

Forming method of bushing with outer sliding surface


The invention relates to a data processing system comprising a central processing unit, a first memory coupled to the central processing unit for storing variable data values, an eventing engine coupled to the central processing unit and the memory to monitor in real-time at least one of the variable data values and determine the occurrence of an event based on the at least one of the variable data values, and a debug module coupled to the central processing unit and to the eventing engine for receiving the at least one of the variable data values in real time to conduct a real-time debugging of the program.

1. Field of the Invention
The invention relates to debugging a program in real-time.
2. Description of the Related Art
Debugging and development tools for locating and eliminating defects, or bugs, in programs for data processing systems are well known. In the past, debugging tools were able to monitor an associated memory as a program was operating normally, which is referred to as "real-time" debugging. Real-time debugging enables data variable watching during program execution in order to determine whether or not the program is working properly.
Initially, a debug program was executed on the main board of the computer. As both programs and processing systems have increased in speed and complexity, the large increase in data and variables to watch during a debug operation exceeded the processing power of the processor and/or the output of the data bus to permit real-time debugging from software running on the computer. In response, the monitoring of data variables has been limited to obtaining variable updates only when the code is not running or intentionally stopped. Debugging tools typically accomplish this using breakpoints, which halt program execution upon the occurrence of specific events. Data variables generated by the program can then be examined at the breakpoint. This poses a problem, as the program can behave differently when it is halted than it would during normal operation. In addition, this creates severe limitations on debugging abilities, as data variables are not examined between breakpoints.
When real-time debugging is necessary, relatively expensive external hardware is used. The external debugging device has sufficient processor speed and a fast enough data bus to effect the real-time debugging. Many families of processors do not have the ability to provide real-time variable monitoring or debugging. There is, therefore, a need for the ability to debug complex programs in real-time using only standard debugging software and the data processing system itself.


A catheter according to an aspect of the present invention comprises a flexible tubular insert section having, in the outer surface of the distal end side of the insert section, a plurality of notches arranged in the longitudinal direction of the insert section on one side of a plane passing through the longitudinal axis of the insert section, an operating wire passed through the insert section and capable of advancing or retreating to bend the distal end side of the insert section having the notches, and a reinforcing tube put on the insert section to cover substantially the overall length of the whole region of the insert section, except the distal end side of the insert section on which the notches are formed, and to restrain longitudinal compression of the insert section.

The present invention relates to a catheter adapted to be inserted into a narrow region, such as a duct of a living body, and used to perform medical operations, such as injection of a contrast medium, recovery of foreign substances, extraction of cells, ablation of affected parts, insertion of a guide wire, etc.
A catheter that is inserted into a duct of a living body or the like, in order to perform medical operations, such as injection of a contrast medium, recovery of foreign substances, extraction of cells, ablation of affected parts, insertion of a guide wire, etc., generally comprises a flexible elongate insert section and an operating section on the hand side. The distal end side of the insert section can be bent so that the distal end of the insert section is directed toward a desired region in the living body. More specifically, the distal end side of the insert section can be bent by pushing or pulling an operating wire, which is fixedly connected to the distal end portion of the insert section, by means of the operating section on the hand side.
Operation for guiding the catheter into a narrow region deep in the living body is very difficult and requires considerable skill. FIG. 12 shows the way a catheter 102 is guided through the channel of an endoscope 100 to a region near a duodenal papilla 105, and an operative instrument 104 is inserted into a bile duct 106 through the opening of the duodenal papilla 105 by means of the catheter 102 that projects from the channel of the endoscope 100. In this operation, the operative instrument 104 that is inserted in a lumen of the catheter 102, cannot be inserted through the duodenal papilla 105 into the bile duct 106 unless the distal end side of an insert section 102a of the catheter 102 is bent to a given degree in a given direction such that the distal end of the insert section 102a can be exactly directed toward the opening of the duodenal papilla 105.
Conventionally, various attempts have been made to direct the distal end of a catheter toward a desired region of a living body. Described in Jpn. Pat. Appln. KOKAI Publication No. 5-38342, for example, is a technique in which the distal end side of the insert section 102a of the catheter 102 is provided with a plurality of notches 103 that are eccentric to the axis of the insert section 102a so that it easily bends to the side on which the notches 103 are located, as shown in FIG. 12, whereby the insert section 102 can be readily directed toward the target region.
If the insert section 102a is provided with the notches 103 that are eccentric to its axis, as described in Jpn. Pat. Appln. KOKAI Publication No. 5-38342, the bending direction of the insert section 102a can no doubt be regulated to some degree. However, this alone cannot be said to be a radical solution.
In order to guide the catheter 102 to the duodenal papilla 105, the flexible elongate insert section 102a of the catheter 102 is first inserted into the channel of the winding insert section of the endoscope 100 in the living body, and the distal end side of the insert section 102a is caused to project from the distal end of the insert section of the endoscope 100. Thereafter, the projected distal end side of the insert section 102a is bent and directed toward the duodenal papilla. The key factor in this operation is to protrude the insert section 102a of the catheter 102 from the distal end of the insert section of the endoscope 100 with that side of the insert section 102a for the notches 103 directed toward the duodenal papilla 105 (upper side of the drawing), and thereafter, the distal end side of the insert section 102a is bent to a desired degree without failing to maintain this direction of protrusion.
However, the insert section 102a of the catheter 102 may be inserted in any direction into the channel of the endoscope 100. Thus, if the catheter 102 is oriented when the catheter 102 starts to be inserted into the channel of the endoscope 100, the catheter 102 may be redirected by its own rotation or the like in the channel of the endoscope 100 as the catheter 102 passes through the channel of the endoscope 100 that winds intricately in the living body. Consequently, the catheter 102 may fail to be caused to project from the endoscope 100 with that side of the insert section 102a for the notches 103 directed toward the duodenal papilla 105, in some cases.
Even in the case where the catheter 102 can be caused to project from the endoscope 100 with that side for the notches 103 directed toward the duodenal papilla 105, moreover, the distal end of the catheter 102 cannot be directed successfully toward the duodenal papilla 105 unless the catheter 102 is bent without changing the direction of its projection. If the distal end portion of the catheter 102 is provided with the notches 103, in particular, the stiffness of the region with the notches 103 lowers, making it hard to steadily maintain the direction of projection of the catheter 102.
Since the catheter is elongate and flexible, the catheter inevitably meanders as the distal end side of the insert section of the catheter 102 is bent by pushing or pulling the operating wire. In some cases, therefore, a stroke on the hand side cannot be transmitted successfully to the distal end side, meaning that a desired curvature cannot be obtained. If the distal end side of the insert section 102a cannot be bent to a necessary degree, the distal end of the catheter 102 cannot be directed successfully toward the duodenal papilla 105.
Thus, if the catheter 102 cannot be caused to project from the endoscope with the specially provided notches 103 directed toward the duodenal papilla 105, it is hard to direct the distal end of the catheter 102 toward the duodenal papilla 105, in consequence. If the catheter 102 can be caused to project from the endoscope 100 with the notches 103 directed toward the duodenal papilla 105, moreover, the distal end side of the catheter 102 cannot be bent to a desired degree in a desired direction unless a handling force on the hand side can be efficiently accurately transmitted to the distal end side without failing to maintain the direction of its projection. Thus, the distal end of the insert section 102a cannot be directed toward the duodenal papilla 105 exactly and speedily.


A medical balloon catheter assembly includes a balloon having a permeable region and a non-permeable region. The balloon is constructed at least in part from a fluid permeable tube such that the permeable region is formed from a porous material which allows a volume of pressurized fluid to pass from within a chamber formed by the balloon and into the permeable region sufficiently such that the fluid may be ablatively coupled to tissue engaged by the permeable region. The non-permeable region is adapted to substantially block the pressurized fluid from passing from within the chamber and outwardly from the balloon. The porous material may be a porous fluoropolymer, such as porous polytetrafluoroethylene, and the pores may be created by voids which are inherently formed between an interlocking node-fibril network which makes up the fluoropolymer. Such voids may be created according to one mode by expanding the fluoropolymer. The balloon may be formed such that the porous material extends along both the permeable and non-permeable regions. In one mode of this construction, the porous material is porous along the permeable region but is non-porous along the non-permeable region, such as for example by expanding only the permeable region in order to render sufficient voids in the node-fibril network to provide permeable pores in that section. The voids or pores in the porous material may also be provided along both permeable and non-permeable sections but are substantially blocked with an insulator material along the non-permeable section in order to prevent fluid from passing therethrough. The insulator material may be dip coated, deposited, or extruded with the porous material in order to fill the voids. The insulator material may in one mode be provided along the entire working length of the balloon and then selectively removed along the permeable section, or may be selectively exposed to only the non-permeable sections in order to fill the voids or pores there.

The present invention involves a surgical device and methods of manufacture and use. More specifically, it involves a circumferential ablation device assembly and associated methods of manufacture and use. One aspect of the present invention specifically involves an assembly and method incorporating a circumferential band along an intermediate region of an expandable member""s working length for ablating a circumferential region of tissue engaged to the intermediate region at a location where a pulmonary vein extends from a left atrium.
The terms xe2x80x9cbody space,xe2x80x9d including derivatives thereof, is herein intended to mean any cavity or lumen within the body which is defined at least in part by a tissue wall. For example, the cardiac chambers, the uterus, the regions of the gastrointestinal tract, and the arterial or venous vessels are all considered illustrative examples of body spaces within the intended meaning.
The term xe2x80x9cbody lumen,xe2x80x9d including derivatives thereof, is herein intended to mean any body space which is circumscribed along a length by a tubular tissue wall and which terminates at each of two ends in at least one opening that communicates externally of the body space. For example, the large and small intestines, the vas deferens, the trachea, and the fallopian tubes are all illustrative examples of lumens within the intended meaning. Blood vessels are also herein considered lumens, including regions of the vascular tree between their branch points. More particularly, the pulmonary veins are lumens within the intended meaning, including the region of the pulmonary veins between the branched portions of their ostia along a left ventricle wall, although the wall tissue defining the ostia typically presents uniquely tapered lumenal shapes.
Many local energy delivery devices and methods have been developed for treating the various abnormal tissue conditions in the body, and particularly for treating abnormal tissue along body space walls which define various body spaces in the body. For example, various devices have been disclosed with the primary purpose of treating or recanalizing atherosclerotic vessels with localized energy delivery. Several prior devices and methods combine energy delivery assemblies in combination with cardiovascular stent devices in order to locally deliver energy to tissue in order to maintain patency in diseased lumens such as blood vessels. Endometriosis, another abnormal wall tissue condition which is associated with the endometrial cavity and is characterized by dangerously proliferative uterine wall tissue along the surface of the endometrial cavity, has also been treated by local energy delivery devices and methods. Several other devices and methods have also been disclosed which use catheter-based heat sources for the intended purpose of inducing thrombosis and controlling hemorrhaging within certain body lumens such as vessels. Detailed examples of local energy delivery devices and related procedures such as those of the types just described above are variously disclosed in the following references: U.S. Pat. No. 4,672,962 to Hershenson; U.S. Pat. No. 4,676,258 to InoKuchi et al.; U.S. Pat. No. 4,790,311 to Ruiz; U.S. Pat. No. 4,807,620 to Strul et al.; U.S. Pat. No. 4,998,933 to Eggers et al.; U.S. Pat. No. 5,035,694 to Kasprzyk et al.; U.S. Pat. No. 5,190,540 to Lee; U.S. Pat. No. 5,226,430 to Spears et al.; and U.S. Pat. No. 5,292,321 to Lee; U.S. Pat. No. 5,449,380 to Chin; U.S. Pat. No. 5,505,730 to Edwards; U.S. Pat. No. 5,558,672 to Edwards et al.; and U.S. Pat. No. 5,562,720 to Stem et al. ; U.S. Pat. No. 4,449,528 to Auth et al.; U.S. Pat. No. 4,522,205 to Taylor et al.; and U.S. Pat. No. 4,662,368 to Hussein et al.; U.S. Pat. No. 5,078,736 to Behl; and U.S. Pat. No. 5,178,618 to Kandarpa. The disclosures of these references are herein incorporated in their entirety by reference thereto.
Other prior devices and methods electrically couple fluid to an ablation element during local energy delivery for treatment of abnormal tissues. Some such devices couple the fluid to the ablation element for the primary purpose of controlling the temperature of the element during the energy delivery. Other such devices couple the fluid more directly to the tissue-device interface either as another temperature control mechanism or in certain other known applications as a carrier or medium for the localized energy delivery, itself. More detailed examples of ablation devices which use fluid to assist in electrically coupling electrodes to tissue are disclosed in the following references: U.S. Pat. No. 5,348,554 to Imran et al.; U.S. Pat. No. 5,423,811 to Imran et al.; U.S. Pat. No. 5,505,730 to Edwards; U.S. Pat. No. 5,545,161 to Imran et al.; U.S. Pat. No. 5,558,672 to Edwards et al.; U.S. Pat. No. 5,569,241 to Edwards; U.S. Pat. No. 5,575,788 to Baker et al.; U.S. Pat. No. 5,658,278 to Imran et al.; U.S. Pat. No. 5,688,267 to Panescu et al.; U.S. Pat. No. 5,697,927 to Imran et al.; U.S. Pat. No. 5,722,403 to McGee et al.; U.S. Pat. No. 5,769,846; and PCT Patent Application Publication No. WO 97/32525 to Pomeranz et al.; and PCT Patent Application Publication No. WO 98/02201 to Pomeranz et al. To the extent not previously incorporated above, the disclosures of these references are herein incorporated in their entirety by reference thereto.
Atrial Fibrillation
Cardiac arrhythmias, and atrial fibrillation in particular, persist as common and dangerous medical ailments associated with abnormal cardiac chamber wall tissue, and has been observed especially in the aging population. In patients with cardiac arrhythmia, abnormal regions of cardiac tissue do not follow the synchronous beating cycle associated with normally conductive tissue in patients with sinus rhythm. Instead, the abnormal regions of cardiac tissue aberrantly conduct to adjacent tissue, thereby disrupting the cardiac cycle into an asynchronous cardiac rhythm. Such abnormal conduction has been previously known to occur at various regions of the heart, such as, for example, in the region of the sino-atrial (SA) node, along the conduction pathways of the atrioventricular (AV) node and the Bundle of His, or in the cardiac muscle tissue forming the walls of the ventricular and atrial cardiac chambers.
Cardiac arrhythmias, including atrial arrhythmia, may be of a multiwavelet reentrant type, characterized by multiple asynchronous loops of electrical impulses that are scattered about the atrial chamber and are often self propagating. In the alternative or in addition to the multiwavelet reentrant type, cardiac arrhythmias may also have a focal origin, such as when an isolated region of tissue in an atrium fires autonomously in a rapid, repetitive fashion. Cardiac arrhythmias, including atrial fibrillation, may be generally detected using the global technique of an electrocardiogram (EKG). More sensitive procedures of mapping the specific conduction along the cardiac chambers have also been disclosed, such as, for example, in U.S. Pat. No. 4,641,649 to Walinsky et al. and Published PCT Patent Application No. WO 96/32897 to Desai. The disclosures of these references are herein incorporated in their entirety by reference thereto.
A host of clinical conditions may result from the irregular cardiac function and resulting hemodynamic abnormalities associated with atrial fibrillation, including stroke, heart failure, and other thromboembolic events. In fact, atrial fibrillation is believed to be a significant cause of cerebral stroke, wherein the abnormal hemodynamics in the left atrium caused by the fibrillatory wall motion precipitate the formation of thrombus within the atrial chamber. A thromboembolism is ultimately dislodged into the left ventricle which thereafter pumps the embolism into the cerebral circulation where a stroke results. Accordingly, numerous procedures for treating atrial arrhythmias have been developed, including pharmacological, surgical, and catheter ablation procedures.
Several pharmacological approaches intended to remedy or otherwise treat atrial arrhythmias have been disclosed, such as for example according to the disclosures of the following references: U.S. Pat. No. 4,673,563 to Beme et al.; U.S. Pat. No. 4,569,801 to Molloy et al.; and also xe2x80x9cCurrent Management of Arrhythimiasxe2x80x9d (1991) by Hindricks, et al. However, such pharmacological solutions are not generally believed to be entirely effective in many cases, and are even believed in some cases to result in proarrhythmia and long term inefficacy. The disclosures of these references are herein incorporated in their entirety by reference thereto.
Several surgical approaches have also been developed with the intention of treating atrial fibrillation. One particular example is known as the xe2x80x9cmaze procedure,xe2x80x9d as is disclosed by Cox, JL et al. in xe2x80x9cThe surgical treatment of atrial fibrillation. I. Summaryxe2x80x9d Thoracic and Cardiovascular Surgery 101(3), pp. 402-405 (1991); and also by Cox, J L in xe2x80x9cThe surgical treatment of atrial fibrillation. IV. Surgical Techniquexe2x80x9d, Thoracic and Cardiovascular Surgery 101(4), pp. 584-592 (1991). In general, the xe2x80x9cmazexe2x80x9d procedure is designed to relieve atrial arrhythmia by restoring effective atrial systole and sinus node control through a prescribed pattern of incisions about the tissue wall. In the early clinical experiences reported, the xe2x80x9cmazexe2x80x9d procedure included surgical incisions in both the right and the left atrial chambers. However, more recent reports predict that the surgical xe2x80x9cmazexe2x80x9d procedure may be substantially efficacious when performed only in the left atrium, such as is disclosed in Sueda et al., xe2x80x9cSimple Left Atrial Procedure for Chronic Atrial Fibrillation Associated With Mitral Valve Diseasexe2x80x9d (1996). The disclosure of these cited references are herein incorporated in their entirety by reference thereto.
The xe2x80x9cmaze procedurexe2x80x9d as performed in the left atrium generally includes forming vertical incisions from the two superior pulmonary veins and terminating in the region of the mitral valve annulus, traversing the region of the inferior pulmonary veins en route. An additional horizontal line also connects the superior ends of the two vertical incisions. Thus, the atrial wall region bordered by the pulmonary vein ostia is isolated from the other atrial tissue. In this process, the mechanical sectioning of atrial tissue eliminates the arrhythmogenic conduction from the boxed region of the pulmonary veins and to the rest of the atrium by creating conduction blocks within the aberrant electrical conduction pathways. Other variations or modifications of this specific pattern just described have also been disclosed, all sharing the primary purpose of isolating known or suspected regions of arrhythmogenic origin or propagation along the atrial wall.
While the xe2x80x9cmazexe2x80x9d procedure and its variations as reported by Cox and others have met some success in treating patients with atrial arrhythmia, its highly invasive methodology is believed to be prohibitive in most cases. However, these procedures have provided a guiding principle that electrically isolating faulty cardiac tissue may successfully prevent atrial arrhythmia, and particularly atrial fibrillation caused by arrhythmogenic conduction arising from the region of the pulmonary veins.
Less invasive catheter-based approaches to treat atrial fibrillation have been disclosed which implement cardiac tissue ablation for terminating arrhythmogenic conduction in the atria. Examples of such catheter-based devices and treatment methods have generally targeted atrial segmentation with ablation catheter devices and methods adapted to form linear or curvilinear lesions in the wall tissue which defines the atrial chambers. Some specifically disclosed approaches provide specific ablation elements which are linear over a defined length intended to engage the tissue for creating the linear lesion. Other disclosed approaches provide shaped or steerable guiding sheaths, or sheaths within sheaths, for the intended purpose of directing tip. ablation catheters toward the posterior left atrial wall such that sequential ablations along the predetermined path of tissue may create the desired lesion. In addition, various energy delivery modalities have been disclosed for forming atrial wall lesions, and include use of microwave, laser, ultrasound, thermal conduction, and more commonly, radiofrequency energies to create conduction blocks along the cardiac tissue wall.
Further more detailed examples of ablation device assemblies and methods for creating lesions along an atrial wall are disclosed in the following U.S. Patent references: U.S. Pat. No. 4,898,591 to Jang et al.; U.S. Pat. No. 5,104,393 to Isner et al.; U.S. Pat. No. 5,427,119; U.S. Pat. No. 5,487,385 to Avitall; U.S. Pat. No. 5,497,119 to Swartz et al.; U.S. Pat. No. 5,545,193 to Fleischman et al.; U.S. Pat. No. 5,549,661 to Kordis et al.; U.S. Pat. No. 5,575,810 to Swanson et al.; U.S. Pat. No. 5,564,440 to Swartz et al.; U.S. Pat. No. 5,592,609 to Swanson et al.; U.S. Pat. No. 5,575,766 to Swartz et al.; U.S. Pat. No. 5,582,609 to Swanson; U.S. Pat. No. 5,617,854 to Munsif; U.S. Pat. No 5,687,723 to Avitall; U.S. Pat. No. 5,702,438 to Avitall. To the extent not previously incorporated above, the disclosures of these references are herein incorporated in their entirety by reference thereto.
Other examples of such ablation devices and methods are disclosed in the following Published PCT Patent Applications: WO 93/20767 to Stern et al.; WO 94/21165 to Kordis et al.; WO 96/10961 to Fleischman et al.; WO 96/26675 to Klein et al.; and WO 97/37607 to Schaer. To the extent not previously incorporated above, the disclosures of these references are herein incorporated in their entirety by reference thereto.
Additional examples of such ablation devices and methods are disclosed in the following published articles: xe2x80x9cPhysics and Engineering of Transcatheter Tissue Ablationxe2x80x9d, Avitall et al., Journal of American College of Cardiology, Volume 22, No. 3:921-932 (1993); and xe2x80x9cRight and Left Atrial Radiofrequency Catheter Therapy of Paroxysmal Atrial Fibrillation,xe2x80x9d Haissaguerre, et al., Journal of Cardiovascular Electrophysiology 7(12), pp. 1132-1144 (1996). The disclosures of these references are herein incorporated in their entirety by reference thereto.
In addition to those known assemblies just summarized above, additional tissue ablation device assemblies have also been recently developed for the specific purpose of ensuring firm contact and consistent positioning of a linear ablation element along a length of tissue by anchoring the element at least at one predetermined location along that length, such as in order to form a xe2x80x9cmazexe2x80x9d-type lesion pattern in the left atrium. One example of such assemblies includes an anchor at each of two ends of a linear ablation element in order to secure those ends to each of two predetermined locations along a left atrial wall, such as at two adjacent pulmonary veins, so that tissue may be ablated along the length of tissue extending therebetween.
In addition to attempting atrial wall segmentation with long linear lesions for treating atrial arrhythmia, other ablation device and method have also been disclosed which are intended to use expandable members such as balloons to ablate cardiac tissue. Some such devices have been disclosed primarily for use in ablating tissue wall regions along the cardiac chambers. Other devices and methods have been disclosed for treating abnormal conduction of the left-sided accessory pathways, and in particular associated with xe2x80x9cWolff-Parkinson-Whitexe2x80x9d syndrome various such disclosures use a balloon for ablating from within a region of an associated coronary sinus adjacent to the desired cardiac tissue to ablate. Further more detailed examples of devices and methods such as of the types just described are variously disclosed in the following published references: Fram et al., in xe2x80x9cFeasibility of RF Powered Thermal Balloon Ablation of Atrioventricular Bypass Tracts via the Coronary Sinus: In vivo Canine Studies,xe2x80x9d PACE, Vol. 18, p 1518-1530 (1995); xe2x80x9cLong-term effects of percutaneous laser balloon ablation from the canine coronary sinusxe2x80x9d, Schuger CD et al., Circulation (1992) 86:947-954; and xe2x80x9cPercutaneous laser balloon coagulation of accessory pathwaysxe2x80x9d, McMath L P et al., Diagn Ther Cardiovasc Interven 1991; 1425:165-171. The disclosures of these references are herein incorporated in their entirety by reference thereto.
Arrhythmias Originating from Foci in Pulmonary Veins
Various modes of atrial fibrillation have also been observed to be focal in nature, caused by the rapid and repetitive firing of an isolated center within cardiac muscle tissue associated with the atrium. Such foci may act as either a trigger of atrial fibrillatory paroxysmal or may even sustain the fibrillation. Various disclosures have suggested that focal atrial arrhythmia often originates from at least one tissue region along one or more of the pulmonary veins of the left atrium, and even more particularly in the superior pulmonary veins.
Less-invasive percutaneous catheter ablation techniques have been disclosed which use end-electrode catheter designs with the intention of ablating and thereby treating focal arrhythmias in the pulmonary veins. These ablation procedures are typically characterized by the incremental application of electrical energy to the tissue to form focal lesions designed to terminate the inappropriate arrhythmogenic conduction.
One example of a focal ablation method intended to treat focal arrhythmia originating from a pulmonary vein is disclosed by Haissaguerre, et al. in xe2x80x9cRight and Left Atrial Radiofrequency Catheter Therapy of Paroxysmal Atrial Fibrillationxe2x80x9d in Journal of Cardiovascular Electrophysiology 7(12), pp. 1132-1144 (1996) (previously incorporated by reference above). Haissaguerre, et al. discloses radiofrequency catheter ablation of drugrefractory paroxysmal atrial fibrillation using linear atrial lesions complemented by focal ablation targeted at arrhythmogenic foci in a screened patient population. The site of the arrhythmogenic foci were generally located just inside the superior pulmonary vein, and the focal ablations were generally performed using a standard 4 mm tip single ablation electrode.
Another focal ablation method of treating atrial arrhythmias is disclosed in Jais et al., xe2x80x9cA focal source of atrial fibrillation treated by discrete radiofrequency ablation,xe2x80x9d Circulation 95:572-576 (1997). The disclosure of this reference is herein incorporated in its entirety by reference thereto. Jais et al. discloses treating patients with paroxysmal arrhythmias originating from a focal source by ablating that source. At the site of arrhythmogenic tissue, in both right and left atria, several pulses of a discrete source of radiofrequency energy were applied in order to eliminate the fibrillatory process.
Other assemblies and methods have been disclosed addressing focal sources of arrhythmia in pulmonary veins by ablating circumferential regions of tissue either along the pulmonary vein, at the ostium of the vein along the atrial wall, or encircling the ostium and along the atrial wall. More detailed examples of device assemblies and methods for treating focal arrhythmia as just described are disclosed in Published PCT Patent Application No. WO 99/02096 to Diederich et al., and also in the following pending U.S. patent applications Ser. No. 08/889,798 for xe2x80x9cCircumferential Ablation Device Assemblyxe2x80x9d to Michael D. Lesh et al., filed Jul. 8, 1997; U.S. Ser. No. 08/889,835 for xe2x80x9cDevice and Method for Forming a Circumferential Conduction Block in a Pulmonary Veinxe2x80x9d to Michael D. Lesh, filed Jul. 8, 1997; U.S. Ser. No. 09/199,736 for xe2x80x9cCircumferential Ablation Device Assemblyxe2x80x9d to Chris J. Diederich et al., filed Feb. 3, 1998; and U.S. Ser. No. 09/260,316 for xe2x80x9cDevice and Method for Forming a Circumferential Conduction Block in a Pulmonary Veinxe2x80x9d to Michael D. Lesh.
Another specific device assembly and method which is intended to treat focal atrial fibrillation by ablating a circumferential region of tissue between two seals in order to form a conduction block to isolate an arrhythmogenic focus within a pulmonary vein is disclosed in U.S. Pat. No. 5,938,660 and a related Published PCT Patent Application No. WO 99/00064. The disclosures of these references are herein incorporated in their entirety by reference thereto.
It is an object of the invention to provide a circumferential ablation device assembly, and related method of manufacture and use, which ablates a circumferential region of tissue at a location where a pulmonary vein extends from an atrium by ablatively coupling an ablative fluid medium within an expandable member to the circumferential region of tissue across a circumferential band which circumscribes an intermediate region of the expandable member and engages the circumferential region of tissue when the expandable member is expanded.
It is another object of the invention to provide such a circumferential ablation device assembly, and related methods of use and manufacture, wherein the intermediate region of the expandable member""s working length is constructed at least in part of a porous fluoropolymer material.
It is a further object of the invention to provide such an expandable member with the porous fluoropolymer material along the intermediate region and also with first and second end portions of the working length that do not include a fluoropolymer.
It is another object of the invention to provide a circumferential ablation device assembly, and related methods of manufacture and use, which ablatively couples an ablation element to only a region of tissue engaged to an intermediate region between two end portions along a working length of an expandable member.
It is another object of the invention to provide a medical device assembly which ablatively couples an ablative fluid medium from within an expandable member to only a region of tissue engaged to only a fluid permeable section along the working length of the expandable member.
It is a further object of the invention to provide a circumferential ablation device assembly, and related methods of use and manufacture, that includes a balloon with elastomeric first and second end portions along its working length and also with a fluid permeable circumferential band circumscribing an intermediate region between those end portions.
It is a further object of the invention to provide a circumferential ablation device assembly, and related methods of use and manufacture, that includes a balloon having a fluid permeable fluoropolymer that is integral along the balloon""s working length and includes an insulator on each of two end portions of the working length such that only a circumferential band circumscribing an intermediate region between the end portions is left permeable. It is a further object to provide such a balloon with the two end portions impregnated with a filler as fluid insulation.
It is a further object of the invention to provide a circumferential ablation device assembly, and related methods of use and manufacture, that includes an expandable member having a working length constructed of an elastomeric wall that is constructed to be fluid permeable along only a circumferential band which circumscribes an intermediate region located between two end portions of the working length.
It is a further object of the invention to provide a circumferential ablation device assembly, and related methods of use and manufacture, that includes a balloon with a fluoropolymeric material that is integral along the balloon""s working length while only an intermediate region between two end portions of the working length is fluid permeable to allow for ablative coupling of an ablation medium across the fluoropolymeric material.
It is a further object of the invention to provide a circumferential ablation device assembly, and related methods of use and manufacture, that includes a balloon having a working length with relatively elastic first and second end portions and a relatively inelastic intermediate region between the first and second end portions, and which ablates only a circumferential region of tissue surrounding the intermediate region when the balloon is inflated.
It is a further object of the invention to provide a medical device catheter having a balloon with a working length that has a porous fluoropolymeric permeable section and also an elastomeric section.
It is a further object of the invention to provide such a catheter where the permeable fluoropolymer section is between two elastomeric end portions of the working length.
It is a further object of the invention to provide a circumferential ablation member with an expandable member having a taper along the working length and also with an ablation element coupled to a circumferential area surrounding the taper along the working length.
It is also a further object of the invention to provide a circumferential ablation member which an expandable member that is adapted to seat at a pulmonary vein ostium such that an ablation circumferential band surrounding the working length is aligned with and ablates a region of tissue along the ostium.
It is a further object of the invention to provide a circumferential ablation member for ablating a circumferential region of tissue along a pulmonary vein ostium and which includes an expandable member with a working length having two end portions that have larger outer diameters than an intermediate region of the working length that includes an ablative circumferential band which is adapted to seat at the pulmonary vein ostium.
Other objects of the invention are contemplated which would be apparent to one of ordinary skill based upon the totality of this disclosure, including without limitation the following summary of various modes, aspects, features, and variations of the particular embodiments.
In one mode of the invention, a circumferential ablation device assembly includes an elongate body with a circumferential ablation member along its distal end portion having an expandable member. The expandable member is located along the distal end portion of the elongate body, and is expandable along a working length which encloses at least in part a fluid chamber that is adapted to fluidly couple to a pressurizeable source of fluid. The working length also has first and second end portions and an intermediate region extending between the end portions. The end portions are substantially non-permeable to fluid, whereas the intermediate region is fluid permeable. With the working length expanded to a radially expanded condition, the intermediate region has an expanded outer diameter which is adapted to radially engage the circumferential region of tissue. The working length is thus adapted to allow fluid to pass from within the fluid chamber and outwardly into the permeable section of the intermediate region where it may be ablatively coupled to the engaged circumferential region of tissue.
In one aspect of this mode, the circumferential ablation member includes an ablation electrode element that is constructed to electrically couple to a volume of pressurized electrically conductive fluid passing from within the fluid chamber and into the permeable section of the intermediate region of the working length. Accordingly, current from the electrode element flows through the electrically conductive fluid and outwardly from the ablation member only through the permeable section along the intermediate region and into the circumferential region of tissue for ablation there.
In another aspect of this mode, the permeable section is constructed from a substantially non-permeable material that has a plurality of apertures formed therethrough which form pores to render that section permeable, whereas in another aspect the permeable section is instead constructed from an inherently porous material with the permeability arising from a plurality of pores that are integral to the porous material.
In another aspect of this mode, the permeable section comprises a porous fluoropolymer material, and may be more particularly a porous polytetrafluoroethylene material.
In another aspect of this mode, the expandable member is an inflatable balloon. The balloon is inflatable with pressurized fluid in order to expand from the radially collapsed condition to the radially expanded condition.
In one particular beneficial construction, the balloon along the intermediate region is constructed at least in part from a porous fluoropolymer material which forms the permeable section, and along the first and second end portions the balloon is constructed at least in part from an elastomer.
In another aspect of this mode, the permeable section forms a circumferential band which circumscribes the working length along the intermediate region. In one particular variation of this aspect, the circumferential band has a band length relative to the longitudinal axis and which is substantially shorter than the working length, and may be less than two-thirds the working length or even one-half of the working length.
In another aspect of this mode, the working length has a proximal end and a distal end and also has a tapered shape with a distally reducing outer diameter from the proximal end to the distal end. In one more particular beneficial variation, the tapered shape is xe2x80x9cpearxe2x80x9d-shaped and has a contoured surface between the proximal end and the distal end with a relatively xe2x80x9cforwardxe2x80x9d or xe2x80x9cdistalxe2x80x9d-looking face along the contoured surface adjacent the proximal end. Further to this variation, the permeable section is provided along a distally-looking face and is adapted to be advanced distally against a circumferential region of tissue when expanded, such as in order to ablate a region of tissue along a posterior left atrial wall which surrounds a pulmonary vein ostium and isolates the associated vein from a substantial portion of the left atrium.
Another mode of the invention provides a medical catheter assembly with a balloon positioned along a distal end portion of an elongate body which ablatively couples an ablation element to tissue via an ablative medium provided by a fluid along a fluid permeable portion of the balloon. The balloon defines a fluid chamber and has a working length that is expandable with a volume of pressurized fluid from a radially collapsed condition having a radially collapsed profile to a radially expanded condition having a radially expanded profile which is larger than the radially collapsed profile. The working length further includes a non-permeable section and a permeable section. The non-permeable section is constructed to substantially prevent the pressurized fluid from passing from within the fluid chamber and outwardly through and from the balloon in the radially expanded condition. The permeable section is constructed at least in part of a porous material having a plurality of pores. In the radially expanded condition the pores are constructed to substantially allow the pressurized fluid to pass from within the enclosed chamber and outwardly from the balloon through the permeable section.
In one aspect of this mode, the porous material is constructed at least in part from a porous fluoropolymer material and the plurality of pores are integrally formed in the porous fluoropolymer material.
In one beneficial variation of this aspect, the porous fluoropolymer material includes a porous polytetrafluoroethylene material. The pores according to this variation may be formed by and between a plurality of nodes which are interconnected by a plurality of fibrils that make up the polytetrafluoroethylene material, and may be located along a length of the porous polytetrafluoroethylene material which extends along both the non-permeable and permeable sections.
According to the polytetrafluoroethylene embodiment providing the pores along both the permeable and non-permeable sections, the pores along the non-permeable section are substantially blocked and non-permeable to the pressurized fluid within the fluid chamber and the pores along the permeable section are substantially open and permeable to pressurized fluid within the fluid chamber. Further to this embodiment, the pores along the non-permeable section may be blocked with an insulator material, which may be a polymer, or more specifically an elastomer in order to provide the working length of the balloon elastomeric qualities during in vivo use. In further embodiments, the insulator material may be a deposited material, such as plasma deposited materials, vapor deposited materials, ion beam deposited materials, or sputter coated materials, or may be a dip-coated material, or may be a thermoplastic material which is melted to the porous polytetrafluoroethylene material along the non-permeable section. In still further embodiments, the insulator material may be a coating over the outer surface of the porous polytetrafluoroethylene, such as a tubular material that may be an elastomer which is coaxially disposed relative to the non-permeable section, or may be a filler material within the pores along the non-permeable section.
In one specific beneficial variation, the porous polytetrafluoroethylene material is formed in a porous tube which is relatively non-compliant, and the tubular material further comprises an elastomer which is relatively compliant, such that the balloon in the radially collapsed condition is characterized by the porous polytetrafluoroethylene material in a folded condition and also by the tubular material in a relatively non-stretched condition, and the balloon in the radially expanded condition is characterized by the porous polytetrafluoroethylene material in an unfolded condition and also by the tubular material in a radially stretched condition.
In another variation of the porous polytetrafluoroethylene aspect, the porous material is formed from a tape which is oriented in a helical pattern with adjacent windings which are fused to form a continuous porous tube that defines at least in part the fluid chamber.
In another aspect of this mode, the working length is constructed at least in part from a polytetrafluoroethylene material having a length which extends along both the non-permeable and permeable sections. The polytetrafluoroethylene material according to this aspect is substantially non-porous along the non-permeable section, and is porous along the permeable section to thereby form the porous material.
In one variation of this aspect, the polytetrafluoroethylene material along the non-permeable section includes a plurality of non-permeable pores. The non-permeable pores are sufficiently small to prevent passage of the pressurized fluid from within the fluid chamber and outwardly from the balloon through the non-permeable section, and the polytetrafluoroethylene material along that section is therefore effectively non-porous. In a further more detailed embodiment of this variation, the plurality of pores along the permeable section are formed by and between a first plurality of nodes which are interconnected by a first plurality of fibrils, whereas the plurality of non-permeable pores are formed by and between a second plurality of nodes and interconnecting fibrils.
In another variation of the polytetrafluoroethylene material aspect, the material is expanded from a cured state along the permeable section and is relatively un-expanded and substantially in the cured state along the non-permeable section, such as for example being stretched and unstretched in the permeable and non-permeable sections, respectively.
In another aspect of this mode, the working length includes first and second end portions with an intermediate region extending therebetween. The first end portion includes the non-permeable section, the intermediate region includes the permeable section, and the second end portion includes a second non-permeable section of similar construction to the first non-permeable section.
In one beneficial variation of this aspect, the permeable section forms a circumferential band which circumscribes the working length along the intermediate region. In the radially expanded condition the intermediate region is constructed to radially engage a circumferential region of tissue along a body space wall of a body space, whereas the first and second end portions are further constructed to radially engage first and second adjacent regions of tissue, respectively, on opposite sides of the circumferential region of tissue. The permeable section is adapted to allow a volume of electrically conductive fluid to pass from within the fluid chamber and outwardly from the balloon through the pores. The assembly according to this beneficial variation further includes an ablation electrode which is constructed to electrically couple with the electrically conductive fluid within the fluid chamber and therefore to the circumferential region of tissue as the electrically conductive fluid flows outwardly from the balloon through the permeable section. According to this beneficial assembly, the electrical coupling from the ablation electrode and through the volume of electrically conductive fluid passing through the permeable section is substantially isolated to the circumferential region of tissue engaged by the intermediate region and is substantially shielded from the adjacent regions of tissue by the first and second end portions.
In another aspect of this mode, the non-permeable and permeable sections are located longitudinally adjacent each other along the working length relative to the longitudinal axis, and in one particular variation the permeable section is located distally adjacent the non-permeable section.
In another aspect of this mode, the working length has a proximal section and a distal section and a tapered shape with a distally reducing outer diameter from the proximal section to the distal section, and the permeable section is located along the tapered region. In one particular variation of this aspect, the permeable section forms a circumferential band which circumscribes the working length along the taper.
In another aspect of this mode, the permeable section is further constructed to allow a volume of electrically conductive fluid to pass from within the fluid chamber and outwardly through and from the balloon through the pores, and the assembly further includes an ablation electrode which is constructed to electrically couple to the volume of electrically conductive fluid within the fluid chamber.
Another mode of the invention is a method for forming a medical balloon catheter device assembly which is adapted to deliver a volume of fluid to a region of tissue in a body. This method includes constructing a fluid permeable tube having a permeable section formed at least in part from a porous material. This construction uses a porous material having a plurality of pores which are adapted to allow a volume of pressurized fluid to pass from within and outwardly through the tube, and further results in a tubular construction having a non-permeable section which is adapted to substantially prevent the volume of pressurized fluid from passing from within and outwardly through the tube. This method further includes securing the fluid permeable tube to a distal end portion of an elongate catheter body in order to form a balloon which defines a pressurizeable fluid chamber over the catheter body and which includes a working length that is adapted to radially expand from a radially collapsed condition to a radially expanded condition when the fluid chamber is filled with the pressurized fluid. The method also includes coupling the pressurizeable fluid chamber with a distal port of a fluid passageway that extends along the catheter body between the distal port and a proximal port along the proximal end portion of the elongate catheter body which is adapted to couple to a pressurizeable fluid source, and also includes positioning the permeable section along the working length.
One aspect of this method mode further includes forming a taper along the working length of the balloon having a distally reducing outer diameter, and positioning the permeable section along the taper. The non-permeable section may also be positioned along the taper.
Another aspect of this method includes constructing the fluid permeable tube at least in part from a porous fluoropolymer having a plurality of voids which form the pores.
One variation of this aspect also includes constructing the porous fluoropolymer to include a plurality of nodes which are interconnected with fibrils to form a node-fibril network such that the plurality of voids are formed between the nodes and interconnecting fibrils.
Another aspect of this method mode includes constructing an ablation electrode to electrically couple to an electrical current source and also to the permeable section when the pressurizeable fluid chamber is filled with an electrically conductive fluid.
One variation of this aspect further includes securing the ablation electrode to the distal end portion of the elongate catheter body, and securing the fluid permeable tube to the elongate catheter body on opposite sides of the ablation electrode such that the ablation electrode is positioned within the fluid chamber.
Another aspect of this method mode includes constructing the fluid permeable tube such that both the permeable and non-permeable sections are formed at least in part from the porous material.
One variation of this aspect includes forming the fluid permeable tube such that the is plurality of pores are provided along both the permeable and the non-permeable sections, and substantially blocking the pores along the non-permeable section such that the blocked pores are substantially non-permeable to the volume of fluid when the fluid is pressurized.
One more particular embodiment of this variation includes blocking the pores along the non-permeable section with an insulator material, such as by dip coating the non-permeable section with the insulator material, melting the insulator material to the non-permeable section, or depositing the insulator material along the non-permeable section.
Another more particular embodiment of the insulating variation includes substantially blocking the pores along both the permeable section and the non-permeable section with the insulator material, and then selectively removing the insulator material such that the pores along the permeable section are left open and un-blocked and the pores along the non-permeable section are left blocked. The insulation may be selectively removed in one beneficial method by dissolving the insulator material along the permeable section with a solvent, which process may further include selectively masking the insulator material along the non-permeable section from being exposed to and dissolved by the solvent.
Another mode of the invention includes a method for treating a region of tissue within a body by expanding a balloon from a radially collapsed condition to a radially expanded condition with a volume of pressurized fluid within a fluid chamber defined at least in part by the balloon, forcing the pressurized fluid from within the fluid chamber and outwardly from the balloon through a plurality of pores provided along a permeable section of the balloon, and substantially blocking the pressurized fluid from passing outwardly from and through the balloon along a non-permeable section of the balloon.
One aspect of this method further includes engaging the permeable section with a region of tissue and then forcing the pressurized fluid outwardly from the balloon through the pores along the permeable section and into the region of tissue. Further to this aspect, the pressurized fluid is forced outwardly from the balloon through the permeable section by weeping the fluid into the region of tissue without forming pressurized jets of fluid into the region of tissue.
Another aspect of this method includes engaging the permeable section with a circumferential region of tissue along a body space wall which defines at least in part a body space, and then forcing the pressurized fluid outwardly from the balloon through the pores along the permeable section and in a circumferential pattern into the circumferential region of tissue. One beneficial variation of this aspect of the method includes engaging the permeable section with a circumferential region of tissue along a pulmonary vein or with a circumferential region of tissue which surrounds a pulmonary vein ostium along a posterior left atrial wall. Another beneficial variation includes electrically coupling an ablation electrode to the pressurized fluid which is an electrically conductive fluid, and ablating the circumferential region of tissue with the pressurized fluid as it passes outwardly form the balloon through the permeable section and into the circumferential region of tissue. Further to this variation, the fluid may be passed to the circumferential region of tissue while substantially shielding the adjacent regions of tissue from electrically coupling to the ablation electrode via the pressurized fluid as it passes outwardly from the balloon through the permeable section and into the circumferential region of tissue. A further more detailed embodiment of this shielding variation includes radially engaging the non-permeable section with an adjacent region of tissue adjacent to the circumferential region of tissue engaged with the permeable section. This more detailed embodiment of the method may further include radially engaging a second non-permeable section with a second adjacent region of tissue which is adjacent to the circumferential region of tissue opposite the first adjacent region of tissue.
Another mode of the invention provides a circumferential ablation member with an expandable member constructed of two expandable elements along each of two end portions of the expandable member and a tubular member extending between the expandable elements which includes a circumferential band that is fluid permeable, wherein a fluid chamber is formed by the expandable elements and the tubular member extending therebetween, and such that fluid from the fluid chamber may be ablatively coupled to a circumferential region of tissue engaged by the circumferential band.
In one aspect of this mode, an electrode is adapted to be electrically coupled to the fluid within the chamber and thus to tissue engaged by the permeable circumferential band. In one variation of this aspect, the electrode is provided along an internal catheter shaft extending between the expandable elements.
In another mode, a medical catheter assembly has an expandable member that encloses a fluid chamber and also an inner expansion element such that the expansion element is adapted to expand a first portion of the expandable member""s working length to a different outer diameter than a second portion of the working length.
In one aspect of this mode, the working length of the expandable member further comprises a circumferential band which is permeable to the fluid within the fluid chamber.
In another aspect of this mode, the expandable member encloses first and second inner expansion elements. A tubular wall extends between those outer surfaces to enclose the fluid chamber. The working length of the expandable member includes an intermediate region constructed of the tubular wall, and also first and second end portions on opposite sides of the intermediate region, wherein the first and second inner expansion elements are located along the first and second end portions.
In a further variation of this aspect, the inner expansion elements are adapted to expand to different outer diameters such that the working length is tapered between the first and second end portions, and more particularly in one variation so that the working length has a distally reducing outer diameter.
In another mode, a circumferential ablation device assembly and method provide an elongate body with a circumferential ablation member on the distal end portion that includes a first expandable member, and a second expandable member is further provided along the distal end portion in a longitudinally spaced location relative to the first expandable member. An ablation element cooperates with at least one of the first and second expandable members in order to ablatively couple to tissue engaged therewith in the expanded condition. In one particular aspect of this mode, the ablation element cooperates with the first expandable member which is distal to the second expandable member on the distal end portion, and ablatively couples to tissue engaged by the first expandable member.

Circumferential ablation device assembly and methods of use and manufacture providing an ablative circumferential band along an expandable member


An essentially jam-free bulk loader for a semi-automatic paintball gun includes a storage housing positionable above the gun infeed opening and adapted to hold a quantity of paintballs to be gravity fed to and fired by the gun. Extending downwardly from a bottom outlet opening in the housing is a feed tube having a bottom end portion connectable to outer end of the gun infeed elbow. During normal operation of the loader, a series of paintballs fall into the tube and infeed elbow and are vertically stacked therein for sequential downward delivery to the gu through the inner end of the infeed elbow. If a paintball jam occurs within the storage housing above its outlet opening during firing of the gun, a void is created in a top end portion of the feed tube above the downwardly moving paintball stack. An optical sensor detects the void and responsively actuates a motor driven agitator member within the storage housing adjacent its bottom outlet opening. The driven agitator member forcibly engages and shifts the jamming paintballs to permit additional paintballs to fall through the housing outlet opening into the feed tube and return the paintball delivery stack to its full operating height within the tube and infeed elbow. When this occurs, the sensor detects the filling of the tube void and responsively terminates the operation of the agitator member until it is needed again.

The present invention generally relates to paintball guns, and more particularly relates to bulk loader apparatus used in the sequential gravity feeding of a stored supply of paintballs to the infeed opening of a paintball gun.
The game of paintball has enjoyed great success in recent years and is one in which two or more "military" teams try to capture one another's flags. The players on the teams each carry a CO.sub.2 -powered gun that shoots paintballs--gelatin covered spherical capsules, about the size of bath oil beads, which contain a colored liquid. When a player is hit with a paintball from an adversary's gun, the paintball ruptures and leaves a colored "splat" on the hit player who is then "out" and must leave the game.
As the game of paintball has grown in sophistication, semiautomatic paintball guns--guns that sequentially fire individual paintballs as fast as the trigger can be repeatedly pulled--have become more prevalent. The high firing rate capability of semiautomatic paintball guns has necessitated the use of bulk loader devices in conjunction with such guns.
In a conventional form thereof, a bulk loader device typically comprises a housing which is positioned above and to one side of the gun. The housing is adapted to internally store a relatively large quantity of paintballs (for example 100-200 paintballs) and has a bottom outlet openinq through which the stored paintballs can sequentially drop. Connected to the housing over its bottom outlet opening, and extending downwardly therefrom, is a feed tube that is connectable to the gun's hollow infeed portion--typically a hollow elbow member projecting outwardly from the body of the gun.
During normal operation of the loader, paintballs dropped through its housing outlet opening form a paintball stack, within the feed tube and gun infeed elbow, that is gravity fed to the gun during firing thereof and replenished at its top end from the loader housing. Paintball jams intermittently occur within the loader housing, above its outlet housing, during firing of the gun. These jams prevent the normal gravity delivery of paintballs downwardly through the housing outlet opening, with the result that the paintball stack can be totally depleted by several shots of the gun.
In the past, clearing of such jams has required that the gun be forcibly shaken to dislodge the paintballs causing the jam within the loader housing. This, of course, is highly undesirable since it interrupts the proper aiming of the gun and, of course, correspondingly interrupts the gun user's ability to continue the rapid firing of the gun. In view of this jamming problem typically associated with paintball guns provided with conventional bulk loader devices, it is an object of the present invention to provide a bulk loader device that overcomes or at least substantially reduces this jamming problem.

Jam-free bulk loader for a paintball gun


The invention relates to a sound-damping partition, especially for the internal equipment of buildings. The partition consists essentially of a timer sub-frame (10) and two sets of planting (18, 20) on either wide side (12, 14) of the sub-frame (10) leaving a hollow space (16) filled with air and damping materials (36). To obtain improved airborne sound damping suing simple means, the invention proposes that one of the sets of planking (20) be secured to the sub-frame (10) by means of thick-walled, soft elastic beads of adhesive (32) while the other set of planting (18) is rigidly clamped to said sub-frame (10).

1. Field of the Invention
The invention is related to a sound-damping partition wall, especially for interior structures in buildings, comprising a sub-frame preferably designed to be a wooden frame or post construction, and two sets of planking on either broad side of the sub-frame, leaving therebetween a hollow space filled with air and/or damping material.
2. Description of the Related Art
In known partition walls of this type the planking is connected by mechanical means such as staples, nails, or screws to the wooden sub-frame. The acoustic damping values of such partition walls is not satisfactory, though, even when using thick-walled multiple planking. The sound attenuation that can be achieved therewith is in the order of 46 dB. An improvement of the damping values was in the past only possible with sub-frames in which the posts were replaced by profiled posts made of metal. The sound damping is therein improved by the internal elasticity of the profiled posts, which dampens the flexural vibrations, which are mainly responsible for the transmission of sound, when the planking is rigidly coupled to the posts. In the metal sub-frames it is found to be disadvantageous, though, that these, as opposed to the wooden sub-frames, cannot be used as load bearing walls. Therefore metal sub-frames are not liked to be used especially in the construction of pre-fabricated houses, more so since it would not fit into the production process of the building company which is usually equipped to work with wood.
Based on this it is the object of the invention to improve a partition wall of the type described above such that an increased sound-damping can be achieved with simple means.


A synthetic single crystal diamond for wire drawing die; the process of manufacturing it and a wire drawing die to utilize it are disclosed. At least one plane of the diamond for wire drawing die is a cleavage plane of (111) faces, and the drawing hole of wire drawing die lies vertical to the cleavage plane.. The diamond for the wire drawing die is produced by providing a synthetic single crystal having 20-400 ppm nitrogen of Ib type diamond. A groove is made on the diamond surface parallel to (111) faces employing energy beams such as a laser beam, an ion beam and an electron beam. A wedge is struck into the groove to cleave the diamond, and a plate is obtained. Furthermore, the plate is divided into polyhedrons, employing either an energy beam or a blade. The cleavage plane of the polyhedron is almost parallel to the (111) faces of crystal, therefore the cleavage plane is used as the standard plane to build the drawing hole.

1.1. Technical Field
The present invention relates to a wire drawing die made of synthetic single crystal diamond which is used for various purposes such as drawing copper wire for winding, steel cord, stainless steel wire, welding wire, and the like; and it relates to a method of producing wire drawing dies by cleaving diamond.
1.2. Background Art
Diamond is a material having the greatest hardness and highest modulus of elasticity of all known materials. Furthermore, extremely pure diamond has additionally the highest thermal conductivity and the highest transmittance in the infrared spectrum. Thus, diamond is a material for which there are no comparable substitutes.
There are two general methods for synthesizing diamond using high temperature and high pressure. In one method, carbon material to be converted to diamond is mixed or brought into contact with a solvent metal such as iron, cobalt or nickel. A stable high pressure and temperature whereby the carbon is converted into diamond under the action of the solvent metal is used. According to such a method, the solvent metal penetrates into the carbon material, whereby the carbon is caused to diffuse through the solvent metal which is in the form of a thin film, to generate diamond. According to this method, diamond is spontaneously nucleated, and rapidly grows until it reaches a certain size. Considerable quantities of fine diamond powder have been synthesized by this method to be applied to, e.g. abrasives. However, large diamond crystals of high quality cannot be synthesized by the aforementioned method.
On the other hand, a method of synthesizing large diamond crystals of good quality is disclosed in U.S. Pat. No. 3,297,407 issued Jan. 10, 1967 to R. H. Wentorf, Jr. Furthermore, U.S. Pat. No. 4,632,817 issued Dec. 30, 1986 Yazu, provides a method for synthesizing a number of large diamond crystals of high quality simultaneously from a plurality of seed crystals. This method is generally called a temperature gradient method.
The present invention relates to using a diamond synthesized by the temperature gradient method.
Most diamond crystal dies are made of natural diamond, whose (110) or (111) faces are polished and then at least one face vertical to said faces is also polished for observation of holing. After the preparations, a wire drawing hole which is vertical to (110) or (111) faces is formed by a laser beam, electric discharge or ultrasonic grinding, while observing through the polished face. Synthetic diamond crystals have been marketed and various attempts to use them for wire drawing have been carried out.
However, the tool life using the prior art displayed a wide range and it causes a lack of reliability. Especially, the tool life made of natural single crystal diamonds can vary widely for the following reasons.
First, the faults of the natural diamond crystal wire drawing dies are the following: It is said that the die having a wire drawing hole vertical to the (110) face, has generally the highest wear resistance and the longest life as shown on Junkatsu (Lubrication), vol. 112, No. 11, 1967. However, the tool life of the dies have such a range according to following reasons.
Second, it is difficult to judge precisely where the (110) face is because natural diamonds have been rounded, and have variety of shapes depending upon the degree of dissolution. As a result, it requires considerable skill to determine the (110) faces of a natural diamond used as wire drawing dies. Therefore, most of the wire drawing hole directions are not intended, and it makes the tool life short.
Third, according to the natural diamond, they often have a soft portion and hard portion on one single crystal; the wire drawing hole has partial wear during drawing and such wire drawing holes are deformed varying from complete circles to distorted ones. This is the cause of a shortened tool life.
Recently, high quality synthetic diamond has been obtained by the temperature gradient method and is on the market. In spite of the many attempts to use the synthetic diamond for a wire drawing die, a high quality wire drawing die has not been obtained yet and the reasons are the following:
First, synthesized or slightly polished idiomorphic diamond is generally used for the wire drawing die. In order to hold the diamonds to the tool holders, hexahedron diamond is suitable. This is mainly covered with (100) faces, and the wire drawing holes are vertical to the (100) faces. However, a drawing hole of such direction has inferior wear resistance and a short tool life.
Second, some of the synthetic diamonds don't have uniform concentration of nitrogen. This causes partial wear of the drawing hole.
Third, when the diamond is held to a tool holder using the surfaces of grown diamond or polished surfaces, it requires a large stress to hold the diamond in place, because the friction coefficient between the diamond surfaces and holder is very low. Therefore, the wire drawing die often cracks during drawing.
Concerning the dividing diamond method, cutting and cleavage are well known. In the former method, there are two ways; one of which is represented by the following. A cutting blade in which diamond particles are embedded rotates at high speed, presses forward on the diamond and performs the cutting. The other is thermal cutting, for example, using a laser beam.
Concerning the latter method, a diamond is grooved by the other diamond or a cutting blade and then a knife-shaped wedge is struck in the groove and a diamond is cleaved, as shown on pages 411-412 of Kesshokogaku Handbook. The latter is thought to be the best method to divide a diamond economically, taking advantage of diamond's propensity to be easily cleaved parallel to the (111) faces. The method does not require a width loss equal to the cutting blade, especially when compared to the former method and also does not require a great deal of time to divide.
However, only commercial diamond cutters use this method to divide large diamonds for jewelry and ornamental applications. According to this method, it requires a high level of skill, and the possibility to destroy a high priced diamond is great, and also makes the probability of an uneven divided plane high, as shown in Diamond (Sanyo Shuppan Bouekiu Ltd.), pages 216-218 and "Ceramics" 11 (1976) No. 6 page 520, the method is not used in industrial fields. In addition, it is impossible to divide a diamond to get plural, thin and uniform plates which are indispensable for heat sink and wire drawing dies.
The subjects of the prior art have been made clear by the present inventors' research. They are: The angle between the groove and the cleavage plane (111) faces must be at most 0.5.degree. to obtain an even cleavage plane. However, it is impossible to groove such accuracy using another diamond or a cutting blade because a diamond is hard enough to get such an accuracy of 0.5". Also, the lineability of the groove has to be within 0.1 mm to cleave, but it is very difficult to groove-in such accuracy using the prior arts.

Synthetic single crystal diamond for wiring drawing dies and process for producing the same