Laminated, molded plastic articles having an excellent abrasion resistant coating are prepared by a 2-step process including applying to a mold surface a 100% reactive coating composition, at least partially curing the coating composition, applying to the exposed surface of the cured coating composition a thermoplastic material, and curing the thermoplastic material to form the laminated molded article. The coating composition includes a polyfunctional acrylic monomer, such as dipentaerythritol monohydroxypentacrylate, a mono functional acrylic monomer, such as hydroxymethylacrylate, an acrylic-soluble thermoplastic, such as cellulose acetate butyrate, an aminoplast resin, such as melamine-formaldehyde, and a free radical initiator. The coating composition is at least partially cured by either UV or IR radiation.

This invention relates to coated, molded articles. In one aspect, this invention relates to coated, molded articles comprising a plastic laminated to an abrasion resistant coating while in another aspect, this invention relates to a dual cure, in-mold process for making these articles. In yet another aspect, this invention relates to molded, plastic articles coated with a composition comprising poly- and monofunctional acrylic monomers, acrylic-soluble thermoplastics having hydroxy functionality, and an aminoplast resin.
Molded thermoplastic articles, such as those made from polymethylmethacrylate, polycarbonate, polyester carbonates, polyester and polystryrene, are commonly used in a wide variety of applications including automotive head and tail lamps, glazing, optical lenses, aircraft parts, signs, display and store fixtures and furniture, to name but a few. Since the surfaces of these thermoplastics are quite soft and are easily scratched and marred during normal use, these surfaces are commonly treated with an abrasion resistant coating.
Many coatings have been proposed for post-application onto the finished molded articles. These materials are applied by conventional coating methods such as spraying, dipping, brushing and roll coating. One common type of a post-application coating is the solvent-based, thermally crosslinkable type, such as the polysiloxanes, fluorocarbonvinyl ether copolymers, and polyurethanes. These materials, when cured, offer various degrees of abrasion resistance, gloss, weatherability, chemical resistance, and adhesion to the thermoplastic substrate. However, these materials suffer certain disadvantages, some serious, such as slow cure, high energy requirements to convert and/or eliminate solvent, emission of enviroment damaging solvents, and cosmetically undesirable features, e.g. orange peel, craters, fish eyes and the presence of airborne dust particles.
Another type of post-application coating is the 100% solids, UV radiation-curable coating type. These materials overcome some of the disadvantages associated with the solvent-based materials, such as high energy consumption and solvent emissions but because of their higher viscosities, they suffer even more from the previously described surface defects as well as poor adhesion to some thermoplastic compositions. These materials also have a tendency to stress crack when applied at higher film thickness. The addition of nonreactive thermoplastic polymers or monofunctional monomers can reduce or eliminate cracking, but only with a diminished resistance to abrasion, chemicals and weathering. In addition, the cure of these coatings by UV radiation is inhibited by atmospheric oxygen, and this results in lower molecular weight polymers at the surface and thus a coating with less hardness, abrasion resistance, chemical resistance, gloss and weatherability than would otherwise be the case. This inhibition can be overcome by conducting the cure in an inert atmosphere, but this is comparatively costly and impractical when the article is large and of a complex shape.

Dual cure, in-mold process for manufacturing abrasion resistant, coated thermoplastic articles


An inductor pattern is formed on a substrate. A conductive pattern having a concave-convex structure is formed on the inductor pattern to increase a surface area of the inductor pattern. An insulation layer is formed on the inductor pattern. After a groove is formed such that the insulation layer is removed to expose the inductor pattern, a conductive pattern is conformally formed on the groove and the insulation layer. Thus, a surface area of the inductor pattern as well as a thickness of an inductor increases to obtain an inductor of a high quality factor.

1. Field of the Invention
The present invention relates to a method of forming a semiconductor device and, more particularly, to a method of forming an inductor.
2. Description of Related Art
An inductor is used to apply a complementary metal oxide semiconductor (CMOS) technology to radio-frequency integrated circuits. An inductor is a passive device that is necessary for impedance matching in a high-frequency integrated circuit. Particularly, an inductor used in a high-frequency integrated circuit is required for a high quality factor to reduce phase noise.
FIG. 1 illustrates a cubic structure of a conventional inductor used in a high-frequency integrated circuit and an equivalent circuit diagram thereof. In FIG. 1, Ls denotes a total inductance of a self inductance of a spiral inductor and a mutual inductance between metal lines constituting the inductor; Rs denotes a sum of a DC resistance of the inductor and an AC resistance considering skin effect occurring at a high frequency; Cs denotes a capacitance of a parasitic capacitor formed between metal lines; Cp denotes a capacitance of a parasitic capacitor formed between an inductor and a substrate, the Cp being calculated from a thickness of an insulation layer formed between the substrate and the inductor; and Rp denotes a superhigh frequency leakage effect of a silicon substrate, the superhigh frequency leakage effect being modeled with resistors.
An entire quality factor (Q) of the equivalent circuit shown in FIG. 1 is expressed by the following equation [Equation 1].
                    Q        =                                            Magnetic                                                                                Energy                                                                                (                Em                )                                      -                          Electric                                                                                Energy                                                                                (                Ee                )                                                          Energy                                                                          Loss                                                                                (              Eloss              )                                                          [                  Equation                                                              1                ]
The magnetic energy (Em), electric energy (Ee), and energy loss (Eloss) of Equation 1 are obtained by the following equations [Equation 2] through [Equation 4], respectively.
                    Em        =                                            V              2                                    wLs                                2                                      [                                                                    (                    wLs                    )                                    2                                +                                  Rs                  2                                            ]                                                          [                  Equation                                                              2                ]                                Ee        =                                            V              2                                                  w                                            (                                  Cs                  +                  Cp                                )                                              2                                    [                  Equation                                                              3                ]                                Eloss        =                                            V              2                        2                                          [                                          1                Rp                            +                              Rs                                                                            (                      wLs                      )                                        2                                    +                                      Rs                    2                                                                        ]                                              [                  Equation                                                              4                ]
Referring to Equation 2 through Equation 4, V denotes voltage and w denotes frequency. With the rise of capacitances Cs and Cp of a parasitic capacitor formed by coupling with Rs, the magnetic energy Em becomes greater while electrical energy Ee and energy loss Eloss become smaller. Further, the rise of the capacitance Cs and Cp may result in a higher quality factor which may be obtained by Equation 1. Accordingly, there is a need to reduce a resistance of a conductive layer and a capacitance of a sacrificial capacitor in order to obtain a higher quality factor.
Conventionally, several approaches have been suggested to reduce a capacitance of a parasitic capacitor. One of the approaches is that a grounding metal layer is formed on a substrate to perform shielding, and another is that an inductor is formed and a substrate below the inductor is etched. Unfortunately, these conventional approaches need an extra CMOS process, which increases process cost.
FIG. 2 is a cross-sectional view of a conventional inductor. In the inductor illustrated in FIG. 2 is that metal layers increase in number while reducing a resistance Rs of a conductive layer in order to obtain a high quality factor taking into consideration the above issues, which is disclosed in U.S. Pat. No. 6,062,161.
Referring to FIG. 2, a first insulation layer 5 is formed on a substrate 1. A first conductive pattern 20 is formed on the first insulation layer 5. A second insulation layer 7 is stacked and a second conducive pattern 10 is formed on the first conductive pattern 20. The first and second conductive patterns 20 and 10 are interconnected by a contact hole 30 to constitute an inductor, which result in the effect that a thickness of a conductive layer increases. Thus, a resistance of the conductive layer decreases. A lead wiring 20A connected through a contact hole is formed to results in decreasing the number of entire metal layers. A reference number 10A denotes a lead wiring connected to the second conductive pattern 10, as illustrated in FIG. 1.
As previously stated, a resistance of a conductive layer is equal to sum of DC resistance and an AC resistance reflecting the skin effect arising at a superhigh frequency, of an inductor. An inductor illustrated in FIG. 2 may have an effect to reduce a DC resistance by increasing thickness of a metal layer but may not have an effect to enhance the skin effect arising at a superhigh frequency.
In view of the foregoing, there is a need for a method for forming a an inductor of high-quality factor where a thickness of metal used in the inductor increases to reduce a resistance thereof while reducing the skin effect arising at a superhigh frequency.


An electro-mechanical device cuts plant stems at a desired angle after a stem is inserted into a stem shaft and a sensor triggers activation of a blade along a blade path at a desired angle. A portable device powered by batteries can be used with plantings where they are growing or a powered device can be used for line production or high volume work.

A common method of preparing plant matter for planting or cloning is to cut the stem at an angle using a razor blade. This method is time-consuming, makes it difficult to cut accurate and repeatable angles, and is a potential safety hazard to the worker. This activity is common to many agricultural operations.

Apparatus for automatic stem cutting for plant propagation


A radio transmitter includes an orthogonal transformation unit for carrying out an orthogonal transformation on pilot signals having orthogonal relation to each other between transmission antennas and a pilot multiplexing unit multiplexing the pilot signals and transmission data, and a radio receiver includes a channel estimation unit obtaining a channel estimate of a directive multibeam for each of reception antennas, an inverse transformation unit carrying out an inverse transformation of the orthogonal transformation on the obtained channel estimate and a received signal processing unit selectively conducting first processing based on the beam channel estimate in the first mode or second processing based on the channel estimate obtained by the inverse transformation unit in the second mode. This commonizes a common pilot for MIMO (second mode) and individual pilots for AAA (first mode), thus realizing the coexistence of MIMO and AAA without leading to a reduction of throughput.

(1) Field of the Invention
The present invention relates to a radio communication system, radio communication method, radio transmitter and radio receiver, and more particularly to a technique suitable for use in a radio communication system employing a plurality of antennas (multiantenna).
(2) Description of the Related Art
[Radio Transmission using Multiantenna]
In recent years, a requirement has been made for a mobile communication system capable of realizing low-SNR (Signal to Noise Ratio) operations and high-speed data transmissions, and such a mobile communication system has been under examination. In this case, as multiantenna systems, for example, there have been known MIMO (Multi-InputMulti-Output) and AAA (Adaptive Array Antenna).
The former (MIMO) is a technique employing a transmitter having a plurality of antennas and a receiver having a plurality of antennas to carry out the transmission and reception of independent data stream through each of the antennas for improving the transmission rate, while the latter (AAA) is a technique of carrying out the transmission and reception of one data stream after the formation of beams with directivity through the use of a transmitter having a plurality of antennas and a receiver having a plurality of antennas for improving communication quality and achieving interference suppression.
The research and development of a multiantenna system for use in a mobile communication system and the partial introduction thereinto prevail at present. For example, the AAA was introduced into a portion of a PHS (Personal Handyphone System) and a report was made as "offer of more stable call environment, follow-up of moving telephone, improvement of effective frequency utilization factor to twice or more" (for example, see non-patent document 1 mentioned later). Moreover, a product made by applying the MIMO technique to a radio LAN system appeared, and a report was made as "realization of twice as high as conventional high-speed radio throughput" (for example, see non-patent document 2 mentioned later).
Thus, the application of the multiantenna technique to a mobile communication system already started.
Secondly, a description will be given hereinbelow of a (systematic) research situation of a multiantenna transceiving technique for the application to the mobile communication system in the future.
As various types of multiantenna transceiving techniques, there are (A) MIMO multiplexing method, (B) MIMO diversity method and (C) AAA transceiving method, and a study has been made thereon (for example, see non-patent document 3 mentioned later). A comparative table mentioned in this document is the following table 1.
TABLE 1Comparison Among MultiantennaTransmitter-Receiver Configurations(A) MIMO(C) AAAMultiplexing(B) MIMOTransmissionMethodDiversity MethodMethodEffectIncrease inIncrease inIncrease inInformationDiversity GainAverage ReceptionBit Rate(Improvement ofSIR(High-SpeedCommunication(Improvement ofData Transmission)Quality)Communication Quality)Interval ofLargeLargeSmallAntennas RequiredFadingHighSignalTransmissionAntenna Gain:CorrelationDemultiplexingDiversity Gain:HighCapability:LowLowLowSignalTransmissionAntenna Gain: LowDemultiplexingDiversity Gain:Capability:HighHighInterferenceNoNoExistSuppressionEffect between OwnCell and Other CellRF CircuitUnnecessaryUnnecessaryNecessaryCalibration
As seen from this table 1, the MIMO techniques (A) and (B) are advantageous when the inter-antenna correlation is low (close to no correlation), while the AAA technique (C) is advantageous when the inter-antenna correlation is high (close to 1). Moreover, in the case of the MIMO multiplexing method (A), the information rate is increasable by increasing the number of antennas, while in the case of the MIMO diversity method (B) and the AAA transmission method (C), although the information rate does not increase with an increase in the number of transmission antennas, the diversity gain and the antenna gain are improvable.
In connection with the results in this non-patent document 3, the following patent document 1 (for example, Claims 1 to 3) discloses a method of, in a case in which an SIR (power ratio between a desired signal and an adjacency interference) is below a given threshold, making the switching from a plurality of data streams independent of each other to a plurality of data streams produced from the same data stream. In this case, it can be considered that the former (the plurality of streams) corresponds to the MIMO multiplexing method (A) in the foregoing table 1, while the latter (the same stream) corresponds to the MIMO diversity method (B).
In addition, the following patent document 2 (for example, Claims 1 to 4, 7) discloses a signal transmission system of carrying out a transmission mode for transmitting signals independent of each other from a transmission antenna and a mode for signals dependent on each other through the use of means for estimating a propagation line between transmission and reception, means for estimating a communication capacity at every transmission mode, means for determining a transmission mode and means for calculating a spatial correlation value between antennas in the reception side. With respect to these transmission modes, in the foregoing table 1, the former (independent signal) corresponds to the MIMO multiplexing method (A), while the latter (dependent signal) corresponds to a technique close to the AAA transmission method (C).
Patent Document 1: Japanese Patent Laid-Open No. 2004-72624
Patent Document 2: Japanese Patent Laid-Open No. 2004-194262
Non-Patent Document 1: WILLCOMinc., "H" • Anshinda Phone Adaptive Array • Antenna", [online], [Retrieval Date: Jun. 15, 2005], Internet <URL:http://WWW.willcom−inc.com//p_s/products/h/antenna.h tml>
Non-Patent Document 2: Buffalo Co., Ltd., "AdvancedRadio LAN Technology-MIMO-Mounted" Radio Broadband Router", [online], [Retrieval Date: Jun. 15, 2005], Internet <URL:http://buffalo.melcoinc.co.jp/products/catalog/network/wzr−g108/index.html>
Non-Patent Document 3: Mamoru SAWABASHI and 5 persons, "Outline of Broadband Radio Access System" NTT Technology Journal (the July 2000 issue), p. 20-22
In a radio communication apparatus having a multiantenna, it is considered that a higher data transmission is made in accordance with a situation of communication at any given time for improving the sector (cell) throughput. For realizing this, both the MIMO and AAA may be provided to be selectively used in a switching fashion. Accordingly, it is an object to provide a method of combining the MIMO and the AAA in cooperation.
In the case of a radio line, for compensating for the phase turn occurring in a propagation line, a pilot signal is used which serves as a phase reference. According to the MIMO technique, an orthogonal pilot for each antenna is used to estimate a channel for a signal to be transmitted from each antenna. This pilot signal is used in common among all the users and, hence, it is referred to as a common pilot.
When the MIMO pilot signal is used for the AAA, since a data unit produces and transmits a beam with directivity, different propagation paths are employed between the pilot signal and the data signal and, hence, difficulty is encountered in employ it for the channel estimation. For this reason, there is a need to add a pilot signal with a different directivity and transmit it.
However, this leads to a decrease in transmission rate (throughput) and requires the information on the added pilot signal and the processing therefor. The pilot signal for the AAA is referred to as an individual pilot because it is required for each user.

Radio communication system, radio communication method, radio transmitter and radio receiver


A media separating device (1), in particular a hydraulic accumulator (3), has a movable separator (5) separating two media (7, 9) received in media chambers (11, 13) and differing from each other. A measuring apparatus (15, 115) can detect an overflow of at least one medium (7, 9) from a medium chamber (11, 13) via the separator (5) into the other medium chamber (11, 13) having the other medium (9, 7).

Media, in particular flowable media as defined in the present application, are often used in drive technology, for example, as lubricants and/or coolants or as pressure means in hydraulic installations for transmitting energies from a pressure medium source to a consumer. Flowable media, for example, hydraulic oil or other pressurized fluids are in media separating means, such as hydraulic accumulators, which fulfill a wide variety of functions in hydraulic installations and serve, for example, to store energy, to supply a fluid reserve for emergency actuation of power consuming devices, and to provide pressure surge attenuation and the like. Secure and proper operation of a hydraulic installation requires not only knowledge of physical operating parameters such as pressure or flow velocities, but also information about whether the media separating means itself is trouble-free and functions reliably in operation.
DE 101 52 777 A1 describes a device for determining the quality of a medium, in particular a lubricant and/or coolant, having multiple sensors that deliver an electric output signal as a function of the respective sensor-specific input variable. One sensor is a temperature sensor that delivers an output signal basically dependent only on the temperature of the medium and basically independent of the quality of the medium in particular. Another sensor delivers an output signal that depends on the quality of the medium, as well as the temperature of the medium. The sensors used are arranged on a shared substrate, which substrate can be immersed in the respective medium to be tested. The device designed in this way permits determination of quality-determining parameters of flowable media, independently of their prevailing temperature.
DE 10 2009 010 775 A1 describes a media separating means in the form of a hydraulic accumulator for receiving at least a partial volume of a liquid under pressure. The hydraulic accumulator has a housing with at least one connection point for connecting the hydraulic accumulator to a hydraulic device such as a hydraulic circuit. A data memory is a component of the hydraulic accumulator. The data stored in the data memory can be electronically read out by a read and/or write device situated outside of the hydraulic accumulator. The operating state of the hydraulic accumulator can therefore be determined and monitored reliably. The monitoring can also be automated and controlled by a control unit.
With the known approach, an elastomer diaphragm, designed as a bladder, separates two media chambers from one another inside the accumulator housing. One media chamber preferably has a compressible working gas, such as nitrogen gas, as the medium. The other media chamber is fillable with hydraulic fluid as another pressurized medium, coming from the hydraulic device, through the connection point in the accumulator housing. The filling is accomplished against the compressive force of the working gas, such that the elastomeric separating means "contracts" and moves to this extent. If hydraulic fluid is needed again on the part of the hydraulic device, the separating means "relaxes," and the required amount of fluid is discharged from the accumulator housing through the connection, under the influence of the compressive force of the working gas. A partial amount of fluid usually remains in the accumulator. Due to the permeability of the diaphragm material, an unwanted transfer of the hydraulic fluid to the gas side of the hydraulic accumulator occurs in the long term, which transfer may occur suddenly due to the development of cracks or tears, for example, in the event of failure of the separation diaphragm. The result is that the "working capacity" of the hydraulic accumulator is impaired, or it may even fail completely within the hydraulic circuit, making operation of a hydraulic installation substantially more difficult or even impossible.
DE 40 06 905 A1 has already proposed creating a method and a device that can be used for this method for measuring the pressure of a gas, in particular for determining the gas charge pressure in a hydraulic accumulator and/or for maintaining a preselected pressure setpoint value in the container. An unwanted transfer of hydraulic fluid to the working gas side of the accumulator could be detectable by this system. This approach is relatively complex and is expensive to implement with regard to the multitude of components. Thus, for a corresponding measuring method, a connection that can be used at least temporarily to exchange working gas between the hydraulic accumulator, and a measuring chamber is to be established at least temporarily for a corresponding measuring method. This connection preferably has only a fraction of the container volume and has a pressure measuring apparatus. In addition, the connection between the hydraulic accumulator and a refilling device is also established at least temporarily for maintaining the pressure setpoint value. This refilling device refills the container with gas on the working gas side when the actual pressure value in the container is lower than the setpoint pressure value.

Media separating device, in particular hydraulic accumulator, including associated measuring apparatus and measuring method


The present invention is a signal processing circuit 12 for an electrostatic electroacoustic transducer configured to correct signals input to a single driven electrostatic electroacoustic transducer 15 including a diaphragm 151 and a fixed electrode 152 disposed to face the diaphragm. The signal processing circuit includes a correction value determiner 122 configured to determine a correction value v1 of a level based on a level of the input signals s1 from the sound source, and a level corrector 124 configured to correct the level of the input signals based on the correction value. The level corrector is configured to correct the level of an input signal among the input signals based on the correction value. The input signal corresponds to a signal for displacing the diaphragm to a first direction side on which a fixed electrode is not disposed with respect to a predetermined position.

An electroacoustic transducer converts vibration of air (sound) into an electrical signal, or an electrical signal into vibration of air (sound). Types of the electroacoustic transducer include an electrostatic (condenser type) electroacoustic transducer. The electrostatic electroacoustic transducer includes a diaphragm and a fixed electrode disposed to face the diaphragm. The electrostatic electroacoustic transducer utilizes an electrostatic capacitance between the diaphragm and the fixed electrode or the electrostatic force acting between the diaphragm and the fixed electrode. Therefore, the electrostatic electroacoustic transducer requires a voltage (polarization voltage) to provide a potential difference between the diaphragm and the fixed electrode.
Electrostatic electroacoustic transducers are divided into two types according to a method of adding polarization voltage: a pure condenser type electrostatic electroacoustic transducer and an electret type electrostatic electroacoustic transducer. The pure condenser type electrostatic electroacoustic transducer applies DC voltage (polarization voltage) from an external power supply (polarization power supply) between the diaphragm and the fixed electrode. The electret type electrostatic electroacoustic transducer applies DC voltage (polarization voltage) between the diaphragm and the fixed electrode by holding a charge on the diaphragm or the fixed electrode.
Further, electrostatic electroacoustic transducers are divided into two types according to an arrangement of the fixed electrode: a single driven electrostatic electroacoustic transducer and a push-pull driven electrostatic electroacoustic transducer. In the single driven electrostatic electroacoustic transducer, the fixed electrode is arranged to face a surface of the diaphragm. On the other hand, in the push-pull driven electrostatic electroacoustic transducer, two fixed electrodes are arranged to face both surfaces of the diaphragm with the diaphragm therebetween.
Examples of an audio equipment that converts an electric signal to vibration of air (emitting sound) using such electrostatic electroacoustic transducer include a condenser-type speaker and a condenser-type headphone (earphone).
FIG. 1 is a schematic cross-sectional view illustrating a basic configuration of a conventional single driven electrostatic electroacoustic transducer. The single driven electrostatic electroacoustic transducer includes a diaphragm 1, a fixed electrode 2 having a plurality of openings 2a, and a spacer 3. The fixed electrode 2 is disposed to face a surface of the diaphragm 1 through the spacer 3. A signal voltage 4 is supplied between a conductive film (not illustrated) formed on the diaphragm 1 and the fixed electrode 2.
FIG. 2 is a schematic cross-sectional view illustrating a basic configuration of a conventional push-pull driven electrostatic electroacoustic transducer. The push-pull driven electrostatic electroacoustic transducer includes a diaphragm 1, two fixed electrodes 2 having a plurality of openings 2a, and two spacers 3. Each of the two fixed electrodes 2 are disposed to face a front surface and a rear surface of the diaphragm 1, respectively, through a spacer 3. A signal voltage 4 is supplied between both fixed electrodes 2.
As described above, in the electrostatic electroacoustic transducer that converts the electric signal into the vibration of air, the diaphragm 1 vibrates by an electrostatic force acting between the diaphragm 1 and the fixed electrode 2. That is, the diaphragm 1 is displaced in a direction (first direction) in which the fixed electrode 2 is not disposed by being repelled to the fixed electrode 2 when a charge having the same polarity as the charge held by the fixed electrode 2 is applied. On the other hand, the diaphragm 1 is displaced in a direction (second direction) in which the fixed electrode 2 is disposed by being attracted to the fixed electrode 2 when a charge having a polarity opposite to the charge held by the fixed electrode 2 is applied.
The electrostatic force acting between the diaphragm 1 and the fixed electrode 2 is inversely proportional to a square of the distance between the diaphragm 1 and the fixed electrode 2. Therefore, in the single driven electrostatic electroacoustic transducer illustrated in FIG. 1, when the diaphragm 1 is displaced in the first direction, the electrostatic force becomes weaker as the diaphragm 1 moves away from the fixed electrode 2. On the other hand, when the diaphragm 1 is displaced in the second direction, the electrostatic force becomes stronger as the diaphragm 1 approaches the fixed electrode 2. That is, the amount of displacement of the diaphragm 1 in the first direction is smaller than the amount of displacement of the diaphragm 1 in the second direction (a difference in the amount of displacement of the diaphragm 1 is caused). That is, the displacement (vibration) of the diaphragm 1 in the first direction and the second direction is in an unbalanced state. Thus, when the displacement of the diaphragm 1 is in the unbalanced state, the second harmonic (second order distortion) strongly appears in the output (sound wave) of the electrostatic electroacoustic transducer.
On the other hand, in the push-pull driven electrostatic electroacoustic transducer illustrated in FIG. 2, since the fixed electrodes 2 are disposed on both surfaces of the diaphragm 1, no difference in the amount of displacement of the diaphragm 1 is caused. Therefore, the distortion appearing in the single driven electrostatic electroacoustic transducer does not occur. Therefore, the push-pull driven electrostatic electroacoustic transducer is frequently used as an electrostatic electroacoustic transducer used for a speaker and the like.
However, in the push-pull driven electrostatic electroacoustic transducer, the fixed electrodes 2 are also disposed at a position where the diaphragm 1 faces a surface that emits sound waves. Therefore, the sound waves emitted from the diaphragm 1 pass through the openings 2a of the fixed electrodes 2. As a result, the frequency response in a high frequency range degraded. Therefore, the sound quality of the push-pull driven electrostatic electroacoustic transducer tends to deteriorate, and an audible volume also tends to decrease, as compared with the single driven electrostatic electroacoustic transducer in which sound waves are emitted without passing through the opening 2a of the fixed electrode 2.
To solve such a problem, twin single driven electrostatic electroacoustic transducer having both advantages of the single driven electrostatic electroacoustic transducer and the push-pull driven electrostatic electroacoustic transducer has been proposed (e.g., see Japanese Unexamined Utility Model Application Publication No. S51-44920).
The electrostatic electroacoustic transducer disclosed in Japanese Unexamined Utility Model Application Publication No. S51-44920 includes two diaphragms, a fixed electrode, and two spacers. Each of the two diaphragms is disposed to face both surfaces of the fixed electrode through a spacer. That is, the electrostatic electroacoustic transducer has a structure such that two single driven electrostatic electroacoustic transducers are disposed back-to-back. Each of the two diaphragms includes an electret film. The fixed electrode has electret films on its both sides. When a signal voltage is applied to both diaphragms, the diaphragms are driven to vibrate in the same direction in a state of being acoustically coupled through the fixed electrode disposed between the diaphragms. Therefore, the distortion (second order distortion) generated in the single driven electrostatic electroacoustic transducer hardly occurs in the electrostatic electroacoustic transducer.
However, the structure of the electrostatic electroacoustic transducer disclosed in Japanese Unexamined Utility Model Application Publication No. S51-44920 is complicated as compared with the single driven electrostatic electroacoustic transducer illustrated in FIG. 1. The electrostatic electroacoustic transducer also requires a large number of electret films. Therefore, the manufacturing cost of the electrostatic electroacoustic transducer increases.
Further, a space between one of the diaphragms and the fixed electrode communicates with a space between the other diaphragm and the fixed electrode through a plurality of openings of the fixed electrode. That is, both diaphragms vibrate air in a common closed space. Therefore, the vibration of one of the diaphragms affects the vibration of the other diaphragm. As a result, the distortion (second order distortion) is not sufficiently solved in the electrostatic electroacoustic transducer disclosed in Japanese Unexamined Utility Model Application Publication No. S51-44920.

Electrostatic electroacoustic transducer device, signal processing circuit for electrostatic electroacoustic transducer, signal processing method, and signal processing


Time-resolved fluorescence decay measurements for flowing particles. An apparatus and method for the measurement and analysis of fluorescence for individual cells and particles in flow are described, wherein the rapid measurement capabilities of flow cytometry and the robust measurement and analysis procedures of time-domain fluorescence lifetime spectroscopy are combined. A pulse-modulated cw laser is employed for excitation of the particles. The characteristics and the repetition rate of the excitation pulses can be readily adjusted to accommodate for fluorescence decays having a wide range of lifetimes.

Rapid measurements of fluorescence from individual cells by flow cytometry allows large samples of cells, organisms and subcellular components to be statistically analyzed in a short period of time. See, e.g., Flow Cytometry and Sorting, 2.sup.nd edition, M. R. Melamed, T. Lindmo, and M. L. Mendelsohn eds., Wiley-Liss, N.Y., 1990. For flow cytometric analysis, the cells are stained with fluorescent probes that bind to a specific subcellular component. The fluorescence intensity from these probes, upon excitation by a continuous wave light source, gives a measure of the particular subcellular component in the cell. Flow cytometric measurements find application in a wide range of biological areas such as cell biology (See, e.g., "Cytochemical Techniques For Multivariate Analysis Of DNA And Other Cellular Constituents," by H. A. Crissman and J. A. Steinkamp, in Flow Cytometry And Sorting, 2.sup.nd edition, M. R. Melamed, T. Lindmo, and M. L. Mendelsohn eds., Wiley-Liss, N.Y., 1990, pages 227-248, and "Quantitative Cell Cycle Analysis," by J. W. Gray, F. Dolbeare, and M. G. Pallavicini, in Flow Cytometrv And Sorting, 2.sup.nd edition, M. R. Melamed, T. Lindmo, and M. L. Mendelsohn eds., Wiley-Liss, N. Y., 1990, pages 44514 468.), chromosome analysis and sorting (See, e.g., "Flow Karyotyping And Chromosome Sorting," by J. W. Gray and L. S. Cram in Flow Cytometry And Sorting, 2.sup.nd edition, M. R. Melamed, T. Lindmo, and M. L. Mendelsohn eds., Wiley-Liss, N.Y., 1990, pages 50314 530.), immunology (See, e.g., "Immunofluorescence Techniques," by M. R. Loken, in Flow Cvtometry And Sorting, 2.sup.nd edition, M. R. Melamed, T. Lindmo, and M. L. Mendelsohn eds., Wiley-Liss, N.Y., 1990, pages 341-353.), hematology (See, e.g., "Analysis And Sorting Of Blood And Bone Marrow Cells," by J. W. M. Visser in Flow Cytometry And Sorting, 2.sup.nd edition, M. R. Melamed, T. Lindmo, and M. L. Mendelsohn eds., Wiley-Liss, N.Y., 1990, pages 669-684.), and microbiology (See, e.g., "Application Of Flow Cytometry On Bacteria: Cell Cycle Kinetic, Drug Effects And Quantitation Of Antibody Binding," by H. B. Steen et al., Cytometry 2, 249-257 (1982).).
Recent advances in fluorescence lifetime spectroscopy have shown that the study of fluorescence decay and excited state lifetimes can provide valuable information on subcellular organization, the fluorescence decay of the probes being sensitive to the surrounding microenvironment. See, e.g., Principles Of Fluorescence Spectroscopy, by J. R. Lakowicz, Plenum Press, New York, 1983, and Mechanisms Of Energy Transfer: In Biophysics, W. Hoppe, W. Lohmann, H. Markl, and H. Ziegler eds., Springer Verlag, Berlin, 1983. Fluorescence decay can provide insight into intermolecular interactions at the subcellular level, which are often accompanied by changes in the fluorescence decay of the molecules involved. See, e.g., "Mechanism of Fluorescence Concentration Quenching of Carboxyfluorescein in Liposomes-Energy Transfer to Non-Fluorescent Dimers," by R. F. Chen et al., Anal. Biochem. 172, 61-77 (1988). As a result, it is important to know if any change in the characteristic of the fluorescence decay or the fluorescence lifetime has occurred in a system under investigation. A flow cytometric method that permits detailed time-resolved analysis of fluorescence decays in single cells, is not available. Such analysis by flow cytometry is expected to have many advantages over similar measurements in bulk solution or suspensions in a cuvette (See, e.g., "Fluorescence Lifetime Analysis of DNA Intercalated Ethidium Bromide and Quenching by Free Dye," by D. P. Heller et al., Biophys. Chem. 50, 305-312 (1994) and "Analysis of Fluorescence Quenching in Some Antioxidants from Nonlinear Stern-Volmer Plots," by H. Zeng et al., J. Luminescence 63, 75-84 (1995)), which is another method by which fluorescence decay studies in biological samples are conducted. For example, experiments in a cuvette provide only an average measure for the fluorescence properties of the collection of all the cells contained in the sample. See e.g., D. P. Heller, supra, and "Nanosecond Fluorescence Microscopy," by S. M. Keating et al., Biophys. J. 59, 186-202 (1991). Additionally, since the illumination volume in such measurements is relatively large, the interference from the background signals (fluorescence from unbound dye, Raman scattering from the medium of suspension, etc.) can be significant. A microscope-based system permits analysis of individual cells on a slide. See, S. M. Keating, supra, and "Development of a Streak-Camera Based Time-Resolved Microscope Fluorimeter and Its Application to Studies of Membrane Fusion in Single Cells," by A. Kusumi et al., Biochem. 30, 6517-6527 (1991). However, the speed at which the cells can be studied is slow because each cell must be brought into the illumination region manually. By contrast, however, in a flow cytometer not only is each cell sampled and measured individually, but the rate of sampling is high. Hundreds of cells can be measured per second in a flow cytometer. Since the cells pass through the laser beam in single file, no further adjustments are required from cell to cell, once the flow cytometer is properly aligned. See, e.g., "Flow Cytometer for Resolving Signals From Heterogeneous Fluorescence Emissions and Quantifying Lifetime in Fluorochrome Labeled Cells and Particles by Phase-Sensitive Detection," Rev. Sci. Instrum. 64, 3440-3450 (1993), and "Fluorescence Lifetime Measurements in a Flow Cytometer by Amplitude Demodulation Using Digital Data Acquisition Technique," by C. Deka et al., Cytometry 17, 94-101, (1994). Further, for the fluorescence decay measurements using a microscope, a synchronously pumped cavity dumped dye laser was used (S. M. Keating, supra), with the pump laser being a mode-locked argon-ion laser. By contrast, laser-based flow cytometers use cw lasers for most conventional applications. See, e.g., Melamed, Crissman, Gray, Loken, Visser, and Steen, supra. By using an electrooptic modulator (EOM) it should be possible to conveniently adapt a cw laser for pulsed time-resolved fluorescence decay measurements instead of using an expensive and complicated multilaser, cavity-dumped system.
Measurements of apparent fluorescence lifetimes in single cells have been made in flow cytometers by frequency domain spectroscopy (See, e.g., Lakowicz, supra, and "Phase-Sensitive Fluorescence Spectroscopy: A New Method to Resolve Fluorescence Lifetimes and Emission Spectra of Components in a Mixture of Fluorophores," J. R. Lakowicz et al., J. Biochem. Biophys. Methods. 5, 19-35 (1981)) using a cw laser sinusoidally modulated at a single modulation frequency. See, also., Lakowicz, supra, and "Phase-Resolved Fluorescence Lifetime Measurements for Flow Cytometry," P. G. Pinsky et al., Cytometry 14, 123-135 (1993). In this method, an apparent lifetime is measured from the phase-shift of the fluorescence signal relative to the modulated excitation at the given modulation frequency. This apparent lifetime gives a true measure of the intrinsic fluorescence lifetime if the fluorescence decay is exponential. A phase shift measured at a single modulation frequency, however, cannot, by itself, determine if a particular decay is exponential in form. Moreover, the lifetimes calculated from the measured phase shifts for multiexponential or nonexponential decays depend on the modulation frequency. See, e.g., J. R. Lakowicz et al., "Picosecond Resolution of Tryosime Fluorescence and Anisotropy Decays by 2 GHz Frequency-Domain Fluorometry," by J. R. Lakowicz et al., Biochem. 26, 82-90 (1987), and "Measuring Fluorescence Decay Times by Phase-Shift and Modulation Using the High Harmonic Content of Pulsed Light Sources," by E. Gratton et al., Nuovo Cimento B15, 110-124 (1980). As a result, a single frequency measurement is not sufficient for the analysis of fluorescence decays that do not follow a single exponential law. It is known that in a system where intermolecular interactions between neighboring fluorochromes lead to nonradiative energy transfer and energy migration, the fluorescence decay becomes nonexponential. See, e.g., J. R. Lakowicz, Dorr, and Chen, supra. In addition, nonexponential decays in flow cytometry can also result simply from the fact that the cells are often labeled with multiple probes having different lifetimes. Therefore, an alternative method is required that permits detailed analysis of arbitrary fluorescence decays from individual cells and particles in flow. Time-domain lifetime spectroscopy offers a convenient solution to this problem. In this situation, if the fluorescence intensity due to a pulsed excitation is measured as a function of time and the system's response function is deconvoluted from the recorded fluorescence data, the impulse response function of the fluorescence decay can be extracted for any arbitrary decay law. See, e.g., J. R. Lakowicz; "Deconvolution of Fluorescence and Phosphorescence Decay Curves-Least Squares Method," by W. R. Ware et al., J. Phys. Chem. 77, 2038-2048 (1973); "Correction of Instrumental Time Response Variation with Wavelength in Fluorescence Lifetime Determinations in the Ultraviolet Region," by D. M. Reyner et al., Rev. Sci. Instrum. 48, 1050-1054 (1977); "On the Analysis of Fluorescence Decay Kinetics by the Method of Least Squares," by A. Grinvald et al., Anal. Biochem. 59, 583 (1974); and "Data Reduction and Error Analysis for the Physical Sciences," by P. R. Bevington, McGraw-Hill, New York, 1969. Time-resolved measurements have been reported for flowing streams of dilute solutions of dye molecules. See, e.g., "Detection and Lifetime Measurement of Single Molecules in Flowing Sample Streams by Laser-Induced Fluorescence," by C. W. Wilkerson et al., App. Phys. Lett. 62(17), 2030-2032 (1993) and "Error Analysis of Simple Algorithms for Determining Fluorescence Lifetimes of Ultradilute Dye Solutions," by S. A. Soper et al., AppI. Spectro. 48, 400-405 (1994). These measurements were made by the gated single-photon counting technique using mode-locked lasers at high repetition rates (76 MHz -82 MHz, pulse-to-pulse period 13.2 ns-12.2 ns), and have been concerned with fluorescence decays having lifetimes of the order of 4 ns or less. The analyses were based on the assumption of a single exponential decay. Due to the high repetition rate of the laser in such systems, however, one could not analyze fluorescence decays having lifetimes longer than one third of the repetition time period of the laser pulses, particularly, if the decay were nonexponential. Further, the duration of the data acquisition for these measurements ranged from 3 ms (Wilkerson, supra) to 10 s (Soper, supra). For flow cytometric analysis of biological cells, however, the data for each cell must be acquired within its transit time across the laser beam. Typically, this is on the order of 20 .mu.s. See, e.g., Steinkamp and Deka, supra. Further, in order to be of practical use for biological studies, the measurement and analysis method must be general enough to include both exponential and nonexponential decays. Finally, it must permit analysis of fluorescence decays having lifetimes up to as long as 25 ns (Heller, supra) or longer. Moreover, since the conventional laser-based flow cytometers already use a cw laser for excitation, it would be advantageous and less expensive if the lifetime sensing method could be adapted to use a cw laser.
In "Fluorescence Detection And Size Measurement Of Single DNA Molecules," by Alonso Castro et al., Analytical Chemistry 65, 849-852 (1993), fluorescence in flowing molecules is detected. However, a time-gate window is employed so that only delayed fluorescence is detected. For investigation of nonexponential decay, it is necessary to observe the characteristics of the fluorescence early in the decay curve. In "Time-Resolved Flow Cytometer For The Measurement Of Lanthanide Chelate Fluorescence: I. Concept And Theoretical Evaluation," by Marc A. Condrau et al., Cytometry 16, 187-194 (1994) and in "Time-Resolved Flow Cytometer For The Measurement Of Lanthanide Chelate Fluorescence: II. Instrument Design And Experimental Results," by Marc A. Condrau et al., Cytometry 16, 195-205 (1994), the authors also discuss the measurement of delayed luminescence.
Accordingly, it is an object of the present invention to perform time-resolved fluorescence decay measurements on single particles in flow.
Another object of the invention is to perform time-domain measurements of the fluorescence decay of fluorochrome-labeled single flowing particles that can be adapted to a conventional flow cytometer (using a cw laser), can readily accommodate a wide range of lifetimes, and can be applied to both exponential and nonexponential decays.
Yet another object of the present invention is to perform time-resolved fluorescence decay measurements on single particles in flow in order to extract the complete decay law governing the fluorochromes in the particles.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

The Regents of the University of California


A method of manufacturing a load-transmitting part having at least two lateral engaging surfaces includes stamping a plurality of thin laminas from generally planar stock material. The laminas are stacked together such that the laterally-disposed surfaces of adjacent laminas cooperate to define the lateral engaging surfaces of the part. The laminas are permanently secured together to prevent relative laminar movement when a load is transmitted from one of the lateral engaging surfaces to another of the lateral engaging surfaces.

A conventional method for manufacturing load-transmitting component parts includes stamping a roughly-dimensioned, monolithic blank from continuous strip stock material; heat treating the blank to obtain a desired hardness; broaching or otherwise machining the blank to obtain a desired configuration of the finished part including the part's load bearing or "engaging" surfaces; and then heat treating the part again to reduce the residual stresses resulting from the broaching or machining step. This known method for making monolithic parts, with its multiple steps, is time consuming and costly.
Furthermore, because the stamping and broaching steps are typically performed on a relatively thick piece of material, close tolerances on the configuration of the finished part are costly to obtain. For example, during the stamping step, a punch tool having a configuration of the desired blank is used to punch a blank from continuous strip stock material. The stock material is supported on a die having a hole which likewise has a configuration of the desired blank, but slightly larger than the dimensions of the punch. As the punch forces the stock material through the die, the leading edge of the blank being formed is typically depressed slightly, thereby forming a radius on the leading edge. As the punch forces the stock material further through the die, a portion of the desired blank is sheared from the remaining stock material, thereby forming a substantially smooth shear section. Finally, as the punch forces the stock material completely through the die, the last interconnecting portion between the stock material and the trailing edge of the blank being formed breaks, thus resulting in a die break section which is rough compared to the shear section.
Typically as the thickness of the stock material increases, the radius thus-formed on the leading edge and the size of the die break section likewise increase. Each of these surface defects must typically be removed by broaching or machining, thereby greatly increasing the relative cost of such parts. In response, the prior art teaches the use of an intermediate heat treating step, thereby permitting use of a relatively soft stock material from which to stamp the rough part.
Other known methods of manufacturing load-transmitting component parts involve forging or casting a rough part, and then machining the rough part to obtain the desired configuration of the finished part. While it is possible to achieve close tolerances on the configuration of the finished part, these methods involve significant tooling and equipment costs.

Laminated parts and method of making same

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A system for automatically recognizing a handwriting image and converting such image to text data including a sequence of validated words, has an image input device, a number of handwriting recognition engines, and control unit. A first handwriting recognition engine is responsive to the image input device, for analyzing the data file and providing one or more possible text words for each successive word in the data file. The first handwriting recognition engine further provides a resemblance indication for each possible text word indicating a level of resemblance between its appearance and the appearance of the handwritten word in the data file. In the event that there is not a high level of confidence in the selection of the first handwriting recognition engine, a selection of a validated word is based on the selections of one or more of the other handwriting recognition engines.

The present invention relates to a system and method for reading handwriting and, more particularly, to a system and method for interpreting handwriting and translating the written image into text.
Computer-aided cursive script recognition and hand printed script recognition have become more commonly used as an increasing number of hardware and software devices have been developed which facilitate and implement inputting data into a computer system through a script interface. For example, tablet computers are designed to permit data, text, and graphics to be inputted by an operator moving a stylus over a touch-responsive screen, simulating writing on the screen. Other types of devices, such as the digital pen shown in U.S. Pat. No. 6,985,643, used in conjunction with a specially encoded paper, permit the pen strokes of the user on the paper to be recorded digitally, and this information then easily supplied to a computer system.
After an image is captured digitally, it still must be "recognized," i.e., converted into a series of text words, images, or other data for use by a computer or other device. Various approaches have been taken in the past to recognize digitized images for this purpose. For example, U.S. Pat. No. 6,950,555, issued Sep. 27, 2005 to Filatov et al, discloses a recognition system in which the anticipated appearance of a word or phrase is compared to a digitized image of a written word. Other types of devices have been used to convert a cursive script image, created with an ordinary writing implement, into a digital format, and then translate the image into digital text so that it can be used by a computer system. Some devices of this sort attempt to recognize each letter of each word individually, while other devices recognize cursive script on a word-by-word basis.
It will be appreciated that translating a handwritten message into a digital text message is a complex task. Variations in the style of handwriting among individuals can be significant. Further, cursive script is commonly written in a relaxed manner, so that some of the cursive letters are ill formed, slurred together, or not formed at all. As a consequence, a word written in cursive script may appear very similar to more than one text word. The text word that is judged to have the highest level of similarity in appearance to the anticipated appearance of a cursive script word will, in many cases, depend upon the specific algorithm used by the computer system to assess this similarity. Such unpredictability will, quite naturally, lead to the mis-recognition of words written in cursive script in a significant number of instances.
It is seen, therefore, that a need exists for an improved system and method for automatically recognizing a handwriting image and converting such image to text data, including a sequence of validated words, in which a significant number of the images are accurately recognized.

System and method for automated reading of handwriting


A hand-held transducer probe is overlapped with elastomeric material for improving the friction and softness of the grip of the probe. The elastomeric material comprises a biocompatible material having a tear strength in excess of 110 pounds per inch and a hardness level less than approximately shore A 80. Also disclosed is a method of producing a hand-held transducer probe having an improved grip comprising the steps of assembling an acoustic array and cable assembly; attaching a handle portion over aid acoustic array and cable assembly; and attaching an elastomeric material over at least a portion of said handle portion.

Ultrasound imaging has become increasingly popular because of its ability to obtain images of internal body organs through non-invasive or minimally invasive techniques. Therefore, it is an ideal choice for many preliminary examinations, such as obstetrical or cardiology exams, and screenings for certain types of growth irregularities, such as tumors, without requiring substantial incisions.
Ultrasound imaging systems typically operate by transmitting ultrasound signals through a transducer which contains an array of piezoelectric elements capable of converting an applied voltage into mechanical motion and vice versa. In this way ultrasound acoustic signals can be transmitted into a medium where reflections, caused by impedance mismatches at acoustic interfaces within the medium, are received back at the transducer. Received acoustic signals are then converted back to electrical signals which are sent to a signal processor where, among other things, they are amplified and processed to construct visual image that can be displayed. The signal processor and display are generally a combine unit whereas the ultrasound transducer is typically in the form of a hand-held probe.
Transducer probes are manufactured in many different forms, including small diameter invasive tools such as catheters and endo-cavity probes. Non-invasive probes are usually palm size and hand-held, and are used, for example, in prenatal examinations of a fetus and in diagnosing cardiac health.
The manufacture of complex devices such hand-held transducer probes typically involves the integration of multiple components. FIG. 1 is a perspective view of a typical prior art hand-held transducer probe, generally referred by reference number 100. Transducer 100 is comprised of machined, cast or injection molded components including a nosepiece assembly 112, comprised of a plastic nosepiece and interior acoustic components, an acoustic lens or window 114, a plastic case handle 116 designed to be grasped by the user's hand, a flexible cable 118 for transmitting electrical signals to and from a signal processing unit (not shown), and a strain relief 120 for preventing cable 118 from fraying. Grip features 122, such as raised ribs or depressions are also shown. An alternative construction of case handles 116 comprises attaching together two clam shell-shaped or other part break-up case handle components.
Ultrasound technicians use transducer probes 100 for extended periods of time and utilize a variety of hand-hold positions. Technicians have experienced fatigue while holding onto the transducer probes 100, especially when wearing gloves and employing coupling gel. The variety of hand sizes and grip configurations of technicians cause difficulty in working with current transducer probes 100 for long periods of time. Once formed, rigid case handles 116 are relatively slippery and hard, thereby compounding grip problems for technicians if used alone. Many methods of improving the grip of case handles have been attempted with limited success. For example, increasing the friction of the case handle 116 has been tried by adding textured surfaces and/or raised ribs 122 and depressions to the case handle 116, but these adjustments did not improve the grip problems to the desired degree.
The grip features 122 of the prior art provide some improvement to a more secure grip of the probe 100 than when there are no grip features 122. Operator fatigue is an undesirable outcome of extensive use. Reducing operator fatigue is a favored usability quality.
Traditional transducer case handles 116 are made from the polysulfone, polycarbonate, or rigid polyurethane families of plastics. The case handle 116 material is chosen for structural strength, impact resistance and chemical resistance. The plastic case handle 116 materials employed in the prior art have a relatively low coefficient of friction and can feel slippery in the operator's hand, especially when gloves and gel are used by the ultrasonographer. These polymerics have good engineering properties, but are also hard and non-compliant. When the probe 100 feels slippery, technicians tend to hold the transducer 100 more tightly. The combination of a tight grip on a hard surface for an extended period of time exacerbates the problem of operator fatigue.
Recently, "ergonomic" transducer case handles 116 have been designed to reduce operator fatigue and discomfort by fitting to the human hand for the variety of applications and positions dictated to acquire ultrasound images. An example of such a handle is shown by Barnes et al. in U.S. Pat. No. 4,582,066.
U.S. Pat. No. 5,505,205, by Solomon et al., discloses elastomeric polymers employed as a transmissive interface over the acoustic window (see, for example, window 114 of FIG. 1) for conducting ultrasound energy from the transducer to a patient's body. The polymeric materials of Solomon are chosen so that the sound speed in the polymeric materials approximately matches the speed of sound and the impedance of the soft tissues in the human body. This is a highly specialized and expensive polymeric material. Moreover, this entire probe is not sealed and therefore only the nose piece is immersible in fluid to disinfect the probe. The probe cannot be fully immersed.
U.S. Pat. No. 5,381,795, by Nordgren et al., discloses a transducer design that uses a rubber-like encapsulated boot around the acoustic window of the probe to insulate the patient from the electrical connections to the transducer crystal and to permit immersion of the boot in a sterilizing liquid. The Nordgren patent teaches that the lower portion of the case closes around the boot.
Copending U.S. application Ser. No. 08/646,155 (abandoned), by Van Creveld et al., discloses a transducer probe design wherein a transducer acoustic assembly encapsulated with rubber-like acoustic lens or window material such as room temperature vulcanizing silicone rubber (RTV). The RTV compound forms both the lens and the case handle. There is no use of an underlying hard case handle material. While this copending application partially addresses the grip and comfort problems discussed above, it has certain aesthetic and functional disadvantages. The aesthetic disadvantage of complete encapsulation may limit the perceived functional goal of being a finely engineered medical device. The RTV or similar purpose material is chosen based on its ability to function as a transmissive interface for conducting ultrasound energy from the transducer to a patient's body. It is designed for low acoustic attenuation and for impedance that matches the impedance of body tissue. Preferred RTV compounds require accurate formulas to meet these and other non-acoustic needs, and therefore, are expensive and have relatively low tear strengths. This RTV-type material is also applied over a transducer probe assembly in a relatively expensive and time-consuming casting and curing process. Furthermore, complete coverage of the probe surface with RTV elastomer impedes smooth manipulation of the probe when placed against the patient's skin to obtain an ultrasound reading.
Accordingly, there exists a need for a transducer probe that allows the operator to grip the transducer more comfortably and securely than previously possible while also facilitating desired smooth manipulation in rotating and translating probe position while the probe is placed against a patient's skin.
There also exists a need for a transducer probe that is liquid tight for complete immersion disinfecting fluid.
There also exists a need for a transducer probe grip surface design which can be personalized in size, shape and color design.
There also exists a need for a transducer probe design which can be manufactured at lower cost and with robust, high tear strength materials which will survive mechanical abuse.

Ultrasound transducer probe having case handle grip surfaces


A switched mode power supply (400), comprising a transformer (410) having a primary winding (410-1), a transformer core (410-3) configured to store energy transferred thereto from the primary winding (410-1) during operation, and a secondary winding (410-2) having a first terminal (T1) and a second terminal (T2). The switched mode power supply also has a primary side circuit (Q1, Q2, C1) arranged to generate voltage pulses and thereby to drive the primary winding (410-1) of the transformer (410), and a secondary side circuit comprising a rectification circuit connected to the secondary winding (410-2) at the first and second terminals (T1, T2). The rectification circuit is arranged such that during a forward phase of operation of the switched mode power supply, in which the primary winding (410-1) is driven by the primary side circuit to magnetize, and store energy in, the transformer core (410-3), a current induced to flow in the secondary winding (410-2) from the second terminal (T2) to the first terminal (T1) is output by the rectification circuit. The rectification circuit is further arranged such that during a fly-back phase of operation of the switched mode power supply, in which the magnetization of the transformer core (410-3) is reset, a current induced to flow in the secondary winding from the first terminal (T1) to the second terminal (T2) of the secondary winding (410-2) is output by the rectification circuit so that energy stored in the transformer (410) during the forward phase of operation is output by the rectification circuit.

The switched mode power supply (SMPS) is a well-known type of power converter having a diverse range of applications by virtue of its small size and weight and high efficiency, for example in personal computers and portable electronic devices such as cell phones. A SMPS achieves these advantages by switching one or more switching elements such as power MOSFETs at a high frequency (usually tens to hundreds of kHz), with the frequency or duty cycle of the switching being adjusted using a feedback signal to convert an input voltage to a desired output voltage. A SMPS may take the form of a rectifier (AC/DC converter), a DC/DC converter, a frequency changer (AC/AC) or an inverter (DC/AC).
There are a number of different circuit topologies for switched mode power supplies, and each has its benefits and shortcomings. Among these are the so-called "fly-back" and "forward" topologies, which are widely used for many different SMPS applications. Fly-back converters are simple, low cost isolated converters that are commonly used for low output power applications. Forward converters, on the other hand, are generally used where greater efficiency and power output are required. The principles of operation of typical fly-back and forward converter circuits will now be explained with reference to FIGS. 1A, 1B, 2A and 2B.
FIG. 1A illustrates a typical fly-back converter with an active clamp on the primary side. More specifically, the fly-back converter 100 comprises a fly-back transformer 110 having a primary winding 110-1 and a secondary side winding 110-2 that are wound around the transformer core 110-3 in a turns ratio N=np/ns, where np and ns are the numbers of turns in the primary winding 110-1 and secondary winding 110-2, respectively. The transformer core 110-3 has a gap (e.g. an air gap) for storing magnetisation energy provided by the primary winding 110-1 during operation.
The primary winding 110-1 is connected to an input voltage source by a primary side circuit comprising a capacitor C1 and actively controlled switches Q1 and Q2. Each of Q1 and Q2 may, as in the present example, be provided in the form of a transistor such as a metal-oxide-semiconductor field-effect transistor (MOSFET) or a bipolar junction transistor (BJT). The secondary side circuit of the fly-back converter 100 comprises a rectifier in the form of diode D2 and a capacitor C2, which are connected as shown in FIG. 1A to rectify and filter the secondary winding voltage.
The fly-back converter 100 can be understood to operate by alternating between two "phases" or "modes" of operation (relating to respective portions of the SMPS switching cycle), as will now be explained.
During the first phase of steady state operation, transistor Q1 is turned ON and transistor Q2 is turned OFF (as shown in traces (a) and (b) in FIG. 1B), so that current from the input voltage source flows through Q1 and the primary winding 110-1 (trace (c)) to magnetise the core 110-3 of the fly-back transformer 110 and store energy in the magnetic field. During the first phase of operation, although current flow through the secondary winding 110-2 is blocked because diode D2 is reverse-biased, current is still supplied to the load of the fly-back converter by the (partial) discharging of capacitor C2, as shown in trace (d) in FIG. 1B.
During the second phase of operation, transistor Q1 is turned OFF and transistor Q2 is turned ON, and the active clamp circuit comprising Q2 and C1 resets the magnetisation of the transformer core 110-3. Meanwhile, on the secondary side, diode D2 becomes forward-biased (since the voltage polarities across the windings have reversed) so that the energy stored in the magnetic field of the transformer 110 during the first phase of operation is released into the secondary side circuit to provide a current to the load and charge the capacitor C2.
As mentioned above, the "forward" topology is also widely used in switching converters, and an example of a forward converter will now be described with reference to FIGS. 2A and 2B. The primary side circuit of the forward converter 200 shown in FIG. 2A is the same as that of the fly-back converter 100 of FIG. 1A, and its description will therefore not be repeated. Furthermore, the transformer 210 of the forward converter 200 is substantially the same as the fly-back transformer 110 but may differ in not having a gap in the transformer core for storing energy. The principal differences between forward converter 200 and the fly-back converter 100 thus lie in the configuration of the secondary side circuit; the secondary side circuit of the forward converter 200 comprises diodes D1 and D2 that are connected to the secondary winding 210-2 and to an inductor (or "choke") L1 as shown in FIG. 2A, and a capacitor C2. The forward converter 200 can also be understood to operate by alternating between two phases/modes of operation, as follows.
During the first phase of steady state operation, transistor Q1 is turned ON and transistor Q2 is turned OFF (as shown in traces (a) and (b) in FIG. 2B), so that current from the input voltage source flows through Q1 and the primary winding 210-1 (trace (c)) to induce a voltage (scaled by the turns ratio N) and simultaneous current flow in the secondary winding 210-2. The induced voltage causes diode D1 to become forward-biased such that current is allowed to pass from the secondary winding 210-2 to the converter output via the diode D1 and inductor L1 (trace (d) in FIG. 2B), thereby transferring energy from the primary side to the secondary side of the transformer 210. A part of the transferred energy is stored in the magnetic field of inductor L1. Diode D2 remains reverse-biased during the first phase and does not conduct.
During the second phase of operation, when transistor Q1 is turned OFF, current through the filter inductor L1 continues without abrupt change because diode D2, which is forward-biased by the EMF from inductor L1, provides a free-wheeling path for this current (trace (e) in FIG. 2B). Energy stored in inductor L1 during the first phase of operation will thus be released to capacitor C2.
Although converter circuits of the "fly-back" and "forward" topology are widely used, each topology has certain limitations that are hard to resolve.
For example, the fly-back converter does not need a dedicated choke to smooth the output current. Another advantage of a fly-back converter is that it can boost the voltage; if the duty cycle is greater that 50%, the output will be higher than the turns ratio N of the transformer allows. Normally, a fly-back converter operates with a duty cycle just below 50% for maximum efficiency. Operating with a duty cycle above 50% also requires slope-compensation for stability. In other words, in many applications, the fly-back circuit has to be designed outside the "sweet spot".
Furthermore, although the fly-back converter 100 does not require an output choke, it has the drawback of requiring a relatively large transformer core. In fly-back converters, the gapped transformer inductance results in a zero in the right-half-plane (RHP), which often makes closed-loop compensation in continuous conduction mode (CCM) difficult. Typically, the closed-loop bandwidth in CCM is very narrow and the resulting transient response is very slow. Another drawback of fly-back converters is the requirement of a large output capacitor due to the lack of a second-order low-pass inductor/capacitor filter at the output.
In the forward converter 200, since primary side transistor Q1 can be ON for up to nearly 100% of the time, utilisation of switch components is better than in the fly-back circuit 100 of FIG. 1A; at minimum input voltage (e.g. 36 V), the forward converter 200 operates at almost 100% duty cycle and the primary side transistor Q1 is fully utilised. However, this comes at the expense of needing to provide the forward converter with a choke L1, although the requirements for the output capacitor C2 are reduced. In addition, to avoid transformer saturation, the forward converter 200 requires a magnetisation resetting circuit. All of these increase the component count and manufacturing cost.
In some applications, one of the two topologies described above will clearly be the best choice, while in other applications there is little to choose between them. However, there are also applications where totally different operating conditions are encountered. For instance, the converter may be required to operate in 24 V systems as well as in 48 V systems. Under such circumstances, a converter topology capable of handling a wider input voltage range would be required.
This requirement can be met by the so-called "forward-flyback" (or "fly-forward") topology, which may be more attractive for handling a wider input voltage range (e.g. 18-72 V) than is normally required (e.g. 36-75 V). A fly-forward circuit topology is employed in Ericsson's PKU 5000E series of DC/DC converters, and will now be described with reference to FIGS. 3A and 3B.
FIG. 3A shows an example of a fly-forward converter 300, which has a primary side circuit that is the same as in the fly-back converter 100 and forward converter 200. However, the transformer 310 of the fly-forward converter 300 has, in addition to a gapped core 310-3, two secondary side windings comprising a first winding 310-2a and a second winding 310-2b, each having the same number of turns as the secondary side winding of the transformers 110 and 210. The secondary side of transformer 310 thus effectively has a larger, centre-tapped secondary winding, which enables the fly-forward converter 300 to swap seamlessly between fly-back to forward modes of operation or to co-operate between them.
More specifically, the fly-forward converter 300 has an output choke L1 connecting the centre-tap terminal of the transformer 310 to the converter's output terminal +OUT. The remaining terminals of the secondary coil are each connected to output terminal −OUT by transistors Q3 and Q4 (although diodes with appropriately arranged polarities could alternatively be used instead of these transistors). The fly-forward converter 300 thus uses more windings on the secondary side than the fly-back and forward converter types since its two transformer windings are connected in series. Transistors Q3 and Q4 must withstand double the voltage that is applied to inductor L1.
During the first phase of steady state operation, transistor Q1 is turned ON and transistor Q2 is turned OFF (as shown in traces (a) and (b) in FIG. 3B) so that current from the input voltage source flows through Q1 and the primary winding 310-1 (trace (c)) to induce a voltage (scaled by the turns ratio N) and simultaneous current flow through transistor Q3 and secondary winding 310-2a. Meanwhile, the core 310-3 is magnetised and stores in the magnetic field some of the energy transferred from the primary side. The voltage induced across winding 310-2a causes current flow from the secondary winding 310-2a to the converter output via the inductor L1 (trace (d) in FIG. 3B), thereby transferring energy from the primary side to the secondary side of the transformer 310. Part of the transferred energy is stored in the magnetic field of L1.
During the second phase of operation, transistor Q1 is turned OFF and transistor Q2 is turned ON, and the active clamp circuit resets the magnetisation of the transformer core 310-3. Meanwhile, on the secondary side, transistor Q4 is turned ON so that the fly-back energy stored in the magnetic field of the transformer 310 during the first phase of operation is released into the secondary side circuit to provide a current to the converter's load and charge capacitor C2.
The fly-forward converter 300 has several advantages over the fly-back and forward converters shown in FIGS. 1 and 2. For example, it can operate with a smaller output capacitance than the fly-back converter 100, and requires no output choke (although an output choke may optionally be included, as in the example of FIG. 3A). Furthermore, there is no RHP zero, so that the converter is easy to compensate and has a fast transient response. In addition, no resetting circuitry is needed, although it may nevertheless be provided, as in the example of FIG. 3A.
These advantages make the fly-forward topology an attractive design choice, particularly for switched mode power supplies that are required to operate over a relatively wide input voltage range.

Forward-flyback topology switched mode power supply


An annular drilling device is provided that employs an active or passive, stationary sealing element. The sealing element is made of a low-friction material that contacts the drill pipe and creates a seal.

Blowouts can occur when a column of mud in a wellbore weighs less than the formation pressure. More specifically, pressure within the wellbore will drastically increase when a formation expels hydrocarbon. The pressure increase sends a pressure wave up the wellbore to the surface that can damage the equipment that maintains the pressure within the wellbore. Besides the pressure wave, the hydrocarbons will travel up the wellbore because they are less dense than the mud. If hydrocarbons reach the surface and exit the wellbore through the pressure control stack (described below) before any of the components thereof are closed, there is a high probability that the drilling or production equipment will ignite the hydrocarbons. The resultant explosion or fire is dangerous and often deadly. To minimize blowout risk, drilling rigs must employ a plurality of different pressure control devices commonly referred to as a "pressure control stack," comprised of an annular pressure control device, also known as a Blowout Preventer ("BOP"), a pipe ram pressure control device, and a blind ram pressure control device. If a "closed loop drilling" method is used, a rotating pressure control device (also known as a Rotating Control Device) will be added on top of the conventional pressure control stack. Those of ordinary skill in the art know of other types of pressure control devices. The various pressure control devices are positioned on top of one another, with any other necessary surface connections, such as the choke and kill lines for managed pressure drilling applications and nitrogen injection lines for under-balanced drilling applications. One of skill in the art will appreciate that elimination of one or more pressure control devices in the stack would reduce the overall height thereof, which will provide smaller drilling rigs.
Again, one of the devices in the pressure control stack can be a rotating pressure control device, also referred to as a rotating pressure control head. The rotating pressure control head is located at the top of the pressure control stack and is part of the pressure boundary between the wellbore pressure and atmospheric pressure. The rotating pressure control head creates the pressure boundary by employing a ring-shaped (i.e., a torus) rubber or urethane sealing element that engages and squeezes against the drill pipe, tubing, casing, or other cylindrical members (hereinafter, "drill pipe"). The sealing element allows the drill pipe to be inserted into (i.e., stabbed) and removed from the wellbore while maintaining the pressure differential between wellbore pressure and atmospheric pressure. The sealing element may be shaped such that the wellbore pressure causes a portion of the sealing element to engage the drill pipe. However, some rotating pressure control heads utilizes a mechanism, typically energized with hydraulic fluid, to apply pressure to the outside of the sealing element which forces the inner portions of the sealing element against the drill pipe. The additional pressure applied to the sealing element allows the rotating pressure control head to be used for higher wellbore pressures. The sealing element is firmly engaged onto the rotating drill pipe and rotates with the drill pipe. Thus, outer portions of the sealing element are associated with several bearings and rotating seals that allow the sealing element to rotate.
The sealing element will eventually wear out because of friction caused by drill pipe rotation, reciprocation, and vibration. Additionally, the passage of pipe joints, down hole tools, and drill bits through the rotating pressure control head causes the sealing element to expand and contract repeatedly, which also causes sealing element wear. Other factors may also cause sealing element wear, such as extreme temperatures, dirt and debris, and rough handling. Sealing elements thus require frequent replacement. If a worn sealing element is not replaced, it may rupture, causing a loss of hydraulic fluids and control over the well head pressure.
Currently, visual inspections or time based life span estimates are used to determine when to replace a worn sealing element. Visual inspections are subjective, and may be unreliable. Time based estimates may not consider actual operating conditions. More specifically, if the time based estimate is too conservative, sealing elements are replaced too frequently, causing unnecessary expense and delay. If the time based estimate is too aggressive, the risk for rupture may be unacceptable. Typically, sealing elements are replaced daily at a significant cost as the time to replace the element is substantial.
U.S. Pat. No. 7,380,590 ("the '590 patent") discloses a Rotating Pressure Control Head ("RPCH") having a sealing element fixed in an inner housing where the inner housing is rotatably engaged to an outer housing by an upper bearing and a lower bearing. The RPCH of the '590 patent offers many improvements over the prior art including a shorter stack size, a quick release mechanism for inner housing and sealing element change out, and a reduction in harmonic vibrations. However, wellbore fluid pressure, pressurized hydraulic fluid, and pipe friction against the sealing element exert a net upward or downward force on the inner housing that translates into a load on the upper and lower bearings. The need of bearings to accommodate sealing element rotation adds complexity and expense to rotating pressure control heads. In addition, one or more seals are required to maintain operating pressure and to prevent fluid escape. As one of skill the art will appreciate, these components also increase system complexity and cost.
Those of skill in the art will appreciate that a drill pipe contained within the pressure control stack may bend or otherwise move, wherein the drill pipe will not be located in the center of the pressure control stack, the ideal location. For example, the weight of the drill pipe may cause it to bow or deflect within the pressure control stack. In addition, during offshore drilling operations, wave motion will cause a floating platform to move relative to the ocean floor, which can cause the drill pipe to move within the pressure control stack. Even if the platform is fixed, ocean currents and surges can move the drill casing, which can move the drill pipe. Movement of the drill pipe in the radial direction and away from the center of the pressure control stack may reduce the life of conventional rotating pressure control devices or annulars. For example, a misaligned drill pipe will contact the surfaces of the sealing member unevenly, thereby increasing wear in some areas. In addition, the drill pipe may move away from the sealing element or cause the sealing element to deflect in such a way to create a gap between the drill pipe and the sealing element, which can cause drilling fluid to expel from the pressure control stack.
Another drawback of existing pressure control stack is that it is difficult to interface with a static flowline. More specifically, pressure control stacks include a stack outlet that interconnects to a rigid flowline that receives downhole pressurized fluid. It is often difficult to mate the pressure control stack to the flowline as these components are rarely in the ideal location or alignment. Thus, mating is usually a labor-intensive process wherein plumbers and welders must modify the flowline to make the connection with the pressure control stack. Movement of the pressure control stack, which may be caused by external forces described above, will stress the connection between the pressure control stack outlet and the flowline. One of skill the art will also appreciate that when the pressure control stack, or components thereof, are replaced, the connection between the outlet and the flowline must be broken and reconnected. If a new outlet is not exactly where the old outlet was relocated, additional modifications will be needed.
It is a long felt need to provide a pressure control device that reduces system complexity and costs. The following disclosure describes a passive sealing element that does not require bearings, rotary seals, and the need to apply pressure to a sealing element.


The invention relates to a file stiffener for stiffening a file of the type having a pair of opposed covers hinged to and spaced apart from one another by a spine, in particular for ring binder and lever arch-type files. The file stiffener comprises at least one rigidifying spacer element, and mounting means for mounting the spacer element between the opposed covers, the spacer element being dimensioned to hold the covers apart in a rigid parallel configuration.

THIS invention relates to a file stiffener, and in particular to a stiffener for ring binder and lever arch-type files.
Unless ring binder and lever arch-type files are filled to their capacity, the opposed file covers are inclined towards one another, with the result that, when viewed from above, the file has a triangular or trapezoidal profile. Partly filled files cannot be newly or efficiently stacked together when the spine width is greater than the gap between the free ends of the file cover. Additionally, because file covers are typically open and unsupported on three sides, asymmetrical acute and obtuse angles are defined between the file covers and the spine, so that the covers are not held uniformly at right angles to the spine. This in turn leads to a tendency for the files to tilt sideways and ultimately to deform. Yet another notable disadvantage of conventional lever arch files, is that their design is such that all the weight of the filed contents is supported by only one of the opposing file covers. As the contents get heavier, the vertical shear moment on the opposing file covers become progressively imbalanced, further contributing to instability and distortion of the file.
The rigid parallelepipedal structure of box files avoids the stacking and stability problem which arises with lever arch files. Box files are generally more expensive as well as being more cumbersome and bulky than lever arch files which are capable of accommodating a similar volume of documentation, and they are less convergent to use.


An infant holding device, including an infant holding portion, including a ductile sheet covered with infant-compatible material and a stand portion, adapted to support the infant holding portion in a vertically diagonal position, so that the infant holding portion thereby has a top and a bottom. In one preferred embodiment the ductile sheet is made of aluminum. In an additional preferred embodiment the infant holding portion is separable from the stand portion.

Correct infant positioning is an important adjunct to the care of a premature infant. Although supporting and positioning the infant is recognized as a high priority, health care professionals have mostly used found objects to do the job, such as blankets, pillows, towels. Many positioning aids have been developed, but they have been primarily aimed at restraining movement in two-dimensions, helping to keep the baby from twisting or rolling around on the bed, for example. A simpler approach is the use of pillows or other objects to elevate the head. To accommodate wires and tubes, these devices can be deformed or the user can place several devices around the baby with spaces between them. Unfortunately, when the infant requires respiratory support this big, soft mass of positioning devices gets in the way of the tubing. Another approach, involving the use of small, spaced devices, reduces stability and complicates readjustment. Finally these materials often lose their shape over time, thereby requiring constant monitoring and adjustment.
There are a number of problems with these methods. First, they tend to use solid blocks, rolls, etc. that do not naturally accommodate tubing and wires. This makes it more difficult to attach tubing and wires to the baby without potentially injuring him/her by pushing, pulling, lifting or twisting. Second, they are not adapted to hold the baby above the surface of the bed which would provide a space between the baby and the bed through which wires could be extended; nor does it permit placing the baby at a specific, beneficial position in three dimensions and holding him/her there securely.
In addition, although it is known that a premature infant may be sensitive to the exact position into which he/she is placed, currently available infant support devices do not permit quick and accurate readjustment of infant position. As a consequence, valuable neonatal intensive care unit staff time may be spent readjusting pillows. At the same time, the needs of the infant are ill met, as a position adjustment takes longer and is made less precisely than would be desirable if possible.


The transporting roller (1) has teeth (6) arranged in a distributed manner over the circumference. To allow a high advancing force to be achieved with the transporting roller (1) at the same time as an only low pressing force over a long operating time and service life, at least some of the teeth (6) comprise a main tooth (7) and at least one secondary tooth (9), which is arranged at a distance from the main tooth and has a smaller tooth tip radius (r2) than the main tooth (7). With the secondary teeth (9), there is an additional transfer of force exerted on the workpiece (2). The secondary teeth (9) limit the depth of penetration of the main teeth (7). When there is a high pressing pressure, the secondary teeth (9) penetrate partially into the work-piece (2). The main and secondary teeth (7, 9) penetrate only slightly into the workpiece (2), and so only a small amount of material has to be removed to eliminate any markings.

The invention concerns a transporting roller for advancing workpieces made of wood, plastic, and the like and provided with teeth arranged in distribution about the circumference.
Such transporting rollers are used, for example, in woodworking machines and serve for transporting the pieces of wood to be machined on a support table in this machine. The transporting rollers are pressed with a roller pressure against the pieces of wood to be transported and are driven in rotation. The teeth engage the topside of the pieces of wood and impart to them an advancing force upon rotation.
In known transporting rollers (EP 0 273 172 B1), the teeth are provided with contact surfaces extending transversely to their flank and limiting the penetration depth of the teeth into the workpiece. The number of teeth that penetrate simultaneously into the workpiece, or contact it, depends on the diameter of the transporting roller and the roller pressure. Due to wear, the pointed teeth however become rounded, do not penetrate as easily into the workpiece, and reduce therefore the advancing action. Accordingly, it is necessary to press the transporting roller with greater force onto the workpieces in order to obtain the same advancing effect. In case of abrasive workpieces or abrasive pieces of wood or a long duration of use, the teeth will wear to such an extent that the force transmission from the transporting roller onto the workpiece is achieved only by the contact surfaces. The effect of the transporting roller is thus greatly reduced and can be compensated only, at least partially, by high roller pressure. Higher roller pressures effect greater friction forces on the surface of the workpieces contacting the support table which counteract the advancing direction and advancing force. The wear of the teeth limits thus the service life and duration of use of the transporting roller.
A further aspect is soiling of the transporting roller by resin deposits or by wood chips or splinters that are produced upon penetration into the workpiece. Strongly soiled transporting rollers also cannot penetrate as far and as easily into the workpiece so that the advancing force is reduced.
It is an object of the invention to configure a transporting roller of the aforementioned kind in such a way that with it a high advancing force is achieved with only minimal roller pressure over an extended duration of use and service life of the transporting roller.

Transporting roller for advancing workpieces made of wood, plastic and the like