An external device (20) includes a mount (22), which is placed in front of a subject's eye. A laser (24) is coupled to the mount (22) and emits radiation (26) that is outside of 380-750 nm. A partially-transparent mirror (23) is coupled to the mount (22). An intraocular device (30) is implanted entirely in the subject's eye, and includes a plurality of stimulating electrodes (38), and an energy receiver (32), which receives the radiation (26) from the laser (24) and generates a voltage drop. A plurality of photosensors (34) detect photons (33) and generate a signal. Driving circuitry (36) is coupled to the energy receiver (32) and to the photosensors (34), and receives the signals from the photosensors (34) and utilizes the voltage drop to drive the electrodes (38) to apply currents to the retina in response to the signals from the photosensors (34). Other embodiments are also described.

Retinal malfunction, due to degenerative retinal diseases, is a leading cause of blindness and visual impairment. Implantation of a retinal prosthesis is a technology for restoring some useful vision in individuals suffering from retinal-related blindness.
The retina is a multi-layered light-sensitive structure that lines the posterior, inner part of the eye. The retina contains photoreceptor cells, for example rods and cones, which capture light and convert light signals into neural signals transmitted through the optic nerve to the brain. Rods are responsible for light sensitive, low resolution black and white vision, whereas cones are responsible for high resolution color vision. Most cones lie in the fovea, which defines the center of the retina.
U.S. Pat. No. 6,976,998 to Rizzo et al. describes an externally powered ocular device that is described as a safe and effective retinal prosthesis. The device is described as performing all functions needed of a retinal prosthesis with electronic components that are placed outside the wall of an eye, are powered wirelessly by an external power source, and which provide a patient with a view determined by natural motion of the eye and triggered by natural incident light converging at the retina. An externally powered, light-activated, sub-retinal prosthesis is described in which natural light entering the eye conveys visual details to the sub-retinal prosthesis, while wireless radiofrequency transmission provides the power needed to stimulate the retina, which would be insufficient if it were obtained from the intensity of incoming light alone.
U.S. Pat. No. 4,628,933 to Michelson describes a visual prosthesis for blindness due to retinal malfunction which includes a compact device having a close-packed array of photosensitive devices on one surface thereof. A plurality of electrodes extends from the opposed surface of the device and are connected to the outputs of the photosensitive devices. The device is adapted to be inserted in the posterior chamber of the eye, generally disposed at the focal plane of the optical pathway and impinging on the retina. Anchoring means secure the device with the electrodes operatively connected to the neuron array at the surface of the retina to stimulate the neurons in a pattern corresponding to the illumination pattern of the photosensitive array. The device is powered by externally induced electromagnetic or radio frequency energy, and is encased in a biologically inert housing. An amplifier array may be interposed between the sensing elements and the electrodes to amplify, shape, and time-process the visual signals.
U.S. Pat. No. 6,298,270 to Nisch describes a retina implant that has a substrate with a surface for applying same to a retina. The substrate comprises electrodes for stimulating cells within the retina. The electrodes are provided on the surface and are exposed to visible light impinging on the retina such that stimuli are exerted on the cells by the electrodes. The implant, further, comprises a photovoltaic layer responsive to non-visible light. The stimuli are locally switched utilizing a voltage generated by the photovoltaic layer.
U.S. Pat. No. 6,507,758 to Greenberg et al. describes a device for directly modulating a beam of photons onto the retinas of patients who have extreme vision impairment or blindness. Its purpose is to supply enough imaging energy to retinal prosthetics implanted in the eye which operate essentially by having light (external to the eye) activating photoreceptors, or photo-electrical material. The device is described as providing sufficient light amplification and does it logarithmically. While it has sufficient output light power, the output light level still remains at a described safe level. Most embodiments include balanced biphasic stimulation with no net charge injection into the eye. Both optical and electronic magnification for the image, as for example, using an optical zoom lens, is incorporated. It is described as being otherwise infeasible to zoom in on items of particular interest or necessity. Without proper adjustment, improper threshold amplitudes would obtain, as well as uncomfortable maximum thresholds. Therefore, to adjust for these, a way is described as providing proper adjustment for the threshold amplitudes and maximum comfortable thresholds. Furthermore, to the extent that individual stimulation sites in the retina give different color perceptions, upon stimulation, then colors of the viewed scene is correlated with specific stimulation sites to provide a certain amount of color vision.
U.S. Pat. No. 6,324,429 to Shire et al. describes a chronically-implantable retinal prosthesis for the blind, which is described as restoring some useful vision to patients. The epiretinal devices are described as thin, strong, and flexible and constructed of or encapsulated in known biocompatible materials, which are described as having a long working life in the eye's saline environment. The function of the implants is to electrically stimulate the ganglion cell layer at the surface of the retina using controlled current sources. The implant has planar form and is described as flexible and exceptionally low mass, minimizing patient discomfort and fluid drag. These physical attributes are described as substantially reducing the potential of harm to the most delicate structure of the eye, the retina, and therefore enhance the long term safety and biocompatibility of the device. Since no micro-cables are required to be attached to the device, and its overall form and edges are rounded, the device is described as not stressing the retina during chronic implantation. A provision is also made for nutrients to reach the retinal cells underneath the device to assure their long-term health. The device is meant to process and retransmit images and data to the ganglion cells on the retina surface.
U.S. Pat. No. 5,935,155 to Humayun et al. describes a visual prosthesis comprising a camera for perceiving a visual image and generating a visual signal output, retinal tissue stimulation circuitry adapted to be operatively attached to the user's retina, and wireless communication circuitry for transmitting the visual signal output to the retinal tissue stimulation circuitry within the eye. To generate the visual signal output, the camera converts a visual image to electrical impulses which are sampled to select an image at a given point in time. The sampled image signal is then encoded to allow a pixelized display of it. This signal then is used to modulate a radio frequency carrier signal. A tuned coil pair having a primary and a secondary coil is used to transmit and receive the RF modulated visual signal, which is then demodulated within the eye. The retinal stimulation circuitry includes a decoder for decoding the visual signal output into a plurality of individual stimulation control signals, which are used by current generation circuitry to generate stimulation current signals to be used by an electrode array having a plurality of electrodes forming a matrix. The intraocular components are powered from energy extracted from the transmitted visual signal. The electrode array is attached to the retina via tacks, magnets, or adhesive.
U.S. Pat. No. 7,047,080 to Palanker et al. describes a self-sufficient retinal prosthesis powered by intra-ocular photovoltaic cells illuminated only by ambient light. Photovoltaic cells can be disposed at the periphery of the retina or in the anterior chamber of the eye. An adaptive retinal prosthesis is also provided, such that the number of pixels energized in the prosthesis is selected according to the variable available power from ambient light.
U.S. Patent Application Publication 2006/0282128 to Tai et al. describes intraocular retinal prosthesis systems, and methods for fabricating such prostheses. A prosthesis device includes a cable region that connects an electrode array region with a power and data management region. The electrode array region includes one or more arrays of exposed electrodes, and the power and data management region includes various power and control elements. The power and data management elements, in one aspect, include an RF coil or coils and circuit arrangements and/or chips configured to provide drive signals to the electrodes via a cable and receive power and signals from the RF coil or coils. Each region includes elements fabricated on or in a single polymer layer during the same fabrication process.
U.S. Patent Application Publication U.S. 2007/0191909 to Ameri et al. describes a wide-field retinal prosthesis providing an increased field of vision with a relatively small scleral incision. The retinal prosthesis is described as including a flexible substrate comprising a central member and at least one wing, with an array of electrodes disposed therein that are configured to stimulate the central and peripheral nerves of the retina. The prosthesis can include a desired number of apertures for suitable flexibility.
U.S. Pat. No. 5,597,381 to Rizzo describes a method for epi-retinal implantation of an object into a subject. The method includes rendering the normally transparent cortical vitreous visible and separating at least a portion of a cortical vitreous of the subject away from an adherent retinal surface to form an epi-retinal space between the retina and the separated cortical vitreous material. An object to be implanted may be introduced into the epi-retinal space and the object engaged with a surface of the retina. In preferred embodiments, the object may then be adhered to the surface of the retina. A method for implantation of a neural contact structure for contact with neural tissue, for example, neural tissue of the retina within which are ganglion cells to be electrically stimulated is also described. The contact structure comprises a first portion for attachment to a first bodily location, such as the inner surface of the retina, and a second portion interconnected with the first portion via an interconnection and being held in contact with the neural tissue. The interconnection exhibits a weak restoring force which in conjunction with the geometry of the second portion provides a preselected desired pressure of contact against the neural tissue. As adapted for the retina, the interconnection exhibits a weak restoring force developed in response to curvature of the interconnection along the inner radius of the retina.
U.S. Pat. No. 6,368,349 to Wyatt et al. describes a neural prosthesis for implantation within an eye. The prosthesis includes a foldable substrate and at least one electronic component supported by the substrate. At least one microchannel is disposed within the substrate. Upon inflation, the foldable substrate is described as unfolding to provide for close contact of the electronic component with neural tissue, thus facilitating surgical implantation through a narrow incision, yet allowing the unfolded device to cover a sufficiently large portion of the patient's retina to provide useful vision.
The following references may be of interest:                U.S. Pat. Nos. 2,721,316        2,760,483        4,272,910        4,551,149        4,601,545        4,664,117        4,969,468        5,016,633        5,024,223        5,108,427        5,109,844        5,147,284        5,159,927        5,397,350        5,411,540        5,476,494        5,526,423        5,575,813        5,674,263        5,800,533        5,800,535        5,836,996        5,837,995        5,865,839        5,873,901        5,895,415        5,944,747        6,032,062        6,230,057        6,389,317        6,442,431        6,611,716        6,658,299        6,755,530        7,003,354        7,006,873        7,027,874        7,031,776        7,037,943        7,103,416        7,139,612        7,162,308        7,251,528        7,321,796        PCT application WO 2007/09539
Zrenner E., 2002. "Will retinal implants restore vision?" Science 295(5557), pp. 1022-1025.

This patent is subject to a terminal disclaimer.


A collapsible drilling rig substructure is transported to a drilling site while in a collapsed transportation configuration wherein a raisable floor of the substructure is in a lowered transportation position relative to a fixed drill floor such that an upper surface of the raisable floor is positioned at a first height level above a base of the substructure while an upper surface of the fixed drill floor is positioned at a second height level above the base that is greater than the first height level. The substructure is positioned adjacent to a wellbore location at the drilling site and reconfigured from the lowered transportation configuration to a raised operating configuration by raising the raisable floor to an operating position laterally adjacent to the fixed drill floor while maintaining a height level of the upper surface of the fixed drill floor at the second height level.

1. Field of the Disclosure
The present subject matter is generally directed to mobile drilling rig assemblies, and, in particular, to the use of a collapsible drilling rig substructure to facilitate both highway transportation and drilling site movement of a mobile drilling rig.
2. Description of the Related Art
In many land-based oil and gas drilling operations, drilling rigs are delivered to an oilfield drilling site by transporting the various components of the drilling rig over roads and/or highways. Typically, the various drilling rig components are transported to the drilling site on one or more truck/trailer combinations, the number of which may depend on the size, weight and complexity of the rig. Once at the drilling site, the components are then assembled, and the drilling rig mast is erected to an appropriate operating position. In many applications, the drilling rig mast is raised to a substantially vertical operating position so that drilling operations can be performed so as to drill a wellbore into the earth. For some oil and gas wells, it may be necessary to perform directional drilling operations, such that the drilled wellbore deviates from a substantially vertical orientation to an orientation that is angled to a certain degree from vertical, which in certain applications may even be angled to a substantially horizontal orientation.
In some applications, the target depth of a horizontal leg of a directionally drilled wellbore may be relatively shallow, such as in the range of 300-500 feet, whereas, in other applications, the depth of the horizontal leg may be up to 1500 feet or even deeper. In the case of such near-surface target depths, it may be necessary to initiate the drilling activities at the surface in a non-vertical orientation, i.e., at a non-zero angle relative to horizontal, so that the wellbore can be turned to a substantially horizontal orientation by the time the shallow target depth has been reached. In such cases, specially designed slant rigs may be used, where the drilling rig mast can be adjusted to a specific angle, e.g., at 45° to horizontal, during the drilling operations. Slant rigs can, therefore, provide a marked improvement in near-surface horizontal drilling applications over more traditional land-based oil and gas rigs—i.e., those with a drilling rig mast that is erected to a substantially vertical orientation. However, the relative positioning of the various slant rig components during drilling operations can lead to certain problems and/or inefficiencies during highway and/or road transportation of the slant rig components between oilfield sites, assembly and erection of the slant rig and movement of the assembled slant rig between adjacent wellbores during pad drilling.
FIGS. 1A-1E illustrate one representative prior art mobile drilling rig that has been used for slant rig drilling applications. More specifically, FIG. 1A shows a drilling rig mast assembly structure 120 positioned on a trailer 101, which is pulled by a truck 100 over a highway and/or road surface 105. The trailer 101 is supported by a plurality of wheels 102, the quantity of which may vary depending on the size and/or weight of the mast assembly structure 120. The mast assembly structure 120 includes a drilling mast 110 with a crown block assembly 111 located at an upper end thereof to facilitate movement of a top drive assembly 125 during drilling operations. The mast assembly structure 120 also typically includes one or more hydraulic cylinders 124 that are used for erecting the drilling mast 110 to a desired operating position, e.g., at a 45° angle relative to horizontal, by pivoting the mast 110 about a pinned connection 115. Furthermore, as shown in FIG. 1A, a stiff leg 121 (see, FIG. 1E) is transported in two sections—a lower section 121a that is pivotably connected to the trailer 101, and an upper section 121b that will be connected at its lower end to the lower section 121a and at its upper end to the drilling rig mast 110 after erection so as to support the mast 110 at an appropriate angle. Additionally, the mast assembly structure 120 includes connections 122a, 122b to which a rig substructure 160 (see, FIGS. 1B-1E) will be connected during assembly of the slant rig 195 (see, FIGS. 1D and 1E).
FIGS. 1B and 1C show the rig substructure 160 positioned on a trailer 151, which is pulled by a truck 150 over the highway and/or road surface 105. The trailer 151 is supported by a plurality of wheels 152, the quantity of which varies depending on the size and/or weight of the rig substructure 160. The rig substructure 160 includes a plurality of structural members 165 and bearing pad support beams 161 for supporting the dead and operating loads of the slant rig 195 (see, FIGS. 1D and 1E). Additionally, the rig substructure 160 includes connections 162a, 162b which can be connected to connections 122a, 122b of the mast assembly structure 120 (see, FIG. 1A) during rig assembly. As shown in FIG. 1B, the rig substructure 160 supports a drawworks 170, and, during transportation, also may support the wellhead equipment 190, e.g., a Christmas tree, blowout preventer (BOP), etc., as shown in FIG. 1C.
FIG. 1D shows the slant rig 195 after the rig substructure 160 has been positioned on drilling mats 180, which are placed on the surface 181 of the well site to support the slant rig 195 and other auxiliary drilling equipment (not shown) during drilling operations. Furthermore, the mast assembly structure 120 has been raised so that the connections 162a and 162b can be fastened to the connections 122a and 122b, respectively, on the mast assembly structure 120. Additionally, the drilling rig mast assembly structure 120, including the trailer 101, is supported by a plurality of jacks 130 and/or similar structural supports, the quantity and position of which may depend on the size and weight of the mast assembly structure 120.
FIG. 1E shows the slant rig 195 after the mast 110 has been erected to an appropriate angle for near-surface direction drilling, e.g., at an angle of 45° relative to horizontal. Additionally, the upper and lower sections 121b, 121a of the stiff legs 121 have been assembled so as to support the mast 110, and a drilling line 171 has been sheaved from the drawworks 170 and over the crown block 111 to support the top drive 125 during drilling operations. Furthermore, the wellhead equipment 190 is now positioned in the cellar 191, i.e., the area within the substructure 160 and below the drill floor 163.
In the rig configuration illustrated in FIG. 1E, the drawworks 170 is in a "low" position, such that it is located below the drill floor 163. However, it should be appreciated that the wellhead equipment 190 is effectively contained within a substantially "closed" cellar 191—i.e., one that is enclosed on all four sides: by the mast assembly structure 120 and trailer 101 on the front side, by the structural members 165 of the rig substructure 160 on both the driller's side and the off-driller's side, and by the drawworks 170 on the back side. As such, access to the wellhead equipment 190 for repair and/or maintenance activities during the drilling operations is restricted due to the substantially "closed" cellar 191. Additionally, it should be appreciated that the slant rig 195 cannot be moved from the current wellbore location without first disassembling the respective connections 122a, 122b and 162a, 162b, and then moving the mast assembly structure 120 and the rig substructure 160 away from wellhead equipment 190 in opposite directions. Accordingly, the slant rig 195 shown in FIG. 1E is not easily adapted for use in pad drilling operations, i.e., where multiple adjacent and/or closely-spaced wellbores are drilled at the same site location, as moving the slant rig 195 requires that the rig 195 be disassembled, the components moved on separate trailers, and then reassembled at a new wellbore location.
FIGS. 2A-2D illustrate yet another representative prior art mobile drilling rig that has been used for slant rig drilling applications. As shown in FIG. 2A, a drilling rig mast assembly structure 220 is positioned on a trailer 201 that is supported by a plurality of wheels 202, and which is pulled by a truck 200 over a highway and/or road surface 205. The mast assembly structure 220 includes a drilling mast 210 with a crown block assembly 211 located at an upper end thereof to facilitate movement of a top drive assembly (not shown) during drilling operations. The mast assembly structure 220 also typically includes a pair of hydraulic cylinders 224 that are used for erecting the drilling mast 210 to a desired operating position, e.g., at a 45° angle relative to horizontal, by pivoting the mast 210 about a pinned connection 215. Furthermore, the mast assembly structure 220 also includes a stiff leg 221 that is pivotably connected to the trailer 201 for supporting the drilling rig mast 210 after erection to an appropriate angle.
The mast assembly structure 220 also includes a rig substructure 260 having a drill floor 263, as well as a plurality of structural members 265 and bearing pad support beams 261 for supporting the dead and operating loads of the fully assembled slant rig 295 (see, FIG. 2D) during drilling operations. Additionally, the rig substructure 260 has connections 222a, 222b to which a drawworks box 270b (see, FIGS. 2B-2D) can be connected during assembly of the slant rig 295. As shown in FIG. 2A, a cellar area 291a of the substructure 260 is located below the drill floor 263.
FIG. 2B shows a truck 250 that is used to pull a trailer 251 over the highway and/or road 205. The trailer 251 supports a drawworks 270 mounted on a drawworks skid 270a, and the drawworks box 270b. The drawworks box 270b includes a plurality of structural members 275 and a floor 263b, as well as connections 262a and 262b for fastening the drawworks box 270b to connections 222a and 222b, respectively, on the rig substructure 260 (see, FIG. 2A). A cellar area 291b is located below the floor 263b of the drawworks box 270b, which is enclosed on two sides by the structural members 275. FIG. 2C is an end view of the drawworks box 270b, and shows that the cellar area 291b is substantially open between the structural members 275.
FIG. 2D shows the slant rig 295 after the connections 262a and 262b on the drawworks box 270b have been fastened to the connections 222a and 222b, respectively, on the rig substructure 260, and after the drawworks skid 270a with the drawworks 270 thereon have been positioned on the floor 263b of the drawworks box 270b. Unlike the slant rig 195 illustrated in FIG. 1E and described above, the drawworks 270 of the slant rig 295 is in a "high" position, i.e., substantially at the level of the drill floor 263a. In this assembled configuration, the cellar 291 of the slant rig 295 (which is now made up of the cellar area 291a of the rig substructure 260 and the cellar area 291b of the drawworks box 270b) is enclosed on three sides: by the rig assembly 220 and the trailer 201 on the front side, and by the structural members 265 and 275 on the driller's side and off-driller's side. The cellar 291 is open, however, from the back side of the slant rig 295. The slant rig 295 can, therefore, be moved away from a first wellbore location after drilling operations have been completed by using the truck 200 to move the trailer 201 over the surface 281 of the drilling site and away from the first wellbore location, and thereafter positioned at a second nearby wellbore location. As such, the slant rig 295 shown in FIG. 2D is more readily adaptable for pad drilling operations than the slant rig 195 illustrated in FIGS. 1A-1E.
However, it should be appreciated that, due to the fixed structure of the drawworks box 270b, the height at which the drawworks box 270b must be attached to the rig substructure 260, and the relatively high weight of the drawworks 270 (which may be as much as 30,000 pounds or even greater), the drawworks box 270b and the drawworks 270 must be assembled to the mast assembly structure 220 by using a suitably sized crane (not shown). Furthermore, due to typical height and/or weight restrictions on permits for highway and/or road transportation of heavy equipment, the drawworks box 270b and drawworks 270 usually cannot be transported by the truck 200 and trailer 201 over highways and/or roads in the fully assembled configuration shown in FIG. 2D. As such, a crane must also be used to disassemble the slant rig 295 after the drilling operations at a given pad drilling site have been completed. Accordingly, logistical considerations for using the slant rig 295 in pad drilling operations must include having a crane present at a given pad drilling site prior to the commencement of drilling operations in order to facilitate initial rig assembly. Furthermore, a crane must also be present after the completion of pad drilling operations so as to facilitate rig disassembly for transportation to other pad drilling sites. As may be appreciated, the requirement that a crane be used during these stages can have a significant impact on the overall cost of the drilling operation, as well as the amount of time that may be needed to perform the operations.
Accordingly, there is a need to develop and implement new designs and methods for facilitating the transportation of a mobile drilling rig, such as a slant drilling rig and the like, between various drilling sites without relying on the use of a crane to assemble and disassemble the rig, as well as enabling the mobile drilling rig to be moved between adjacent wellbore locations during pad drilling operations without first disassembling the rig.

Collapsible substructure for a mobile drilling rig


This is a probe that can be used to measure any curl on a stack of sheets in a sheet stacking tray. In printing systems including electrophotographic systems, sheets tend to curl on edge portions. This curl can adversely affect the final copy and copies fed to finishing stations.

In many feeding and finishing modules in marking systems including electrostatic marking systems, a stack of sheets is generally being processed. The topography of the top of the stack is often a critical but uncontrolled factor. If the top of the stack is excessively non-planar in a feeder module, then feeder acquisition failures may occur. Stack non-planarity in a finisher may be indicative of poor quality of finished documents and may result in customer dissatisfaction in the end article. The predominant cause of stack surface non-planarity is sheet curl. Products within the high-end office and production markets typically have some decurling capability. In general, the system operator needs to confirm that the decurling capability is set appropriately for the media type and job type. This may involve visual inspection of the stack quality as it is formed within the finishing module. The operator is thus forced to 'close the loop' to assure that output quality will be acceptable to the end customer. A less subjective and labor intensive process than now exists would be preferable.
Various means have been suggested to measure the degree of curl and flatness at the top of the paper stack. This is important since sheet curl causes problems of handling as the sheet is processed in the feeding, printing or finishing module. Sheets delivered in a curled condition have a tendency to have their edges out of registration with the aligning mechanisms and other sheet moving systems employed in the printing machine. In addition, curled sheets tend to frequently produce jams or misfeeds within the feeding and printing modules, and especially within output sorting, stacking, collating, compiling and/or other sheet handling systems. Belts or soft rollers may be used in conventional prior art decurlers in which one or more paper paths are effective in reducing paper curls primarily in the direction of sheet travel . However, the setting of such decurlers is complex since paper curl is a function of many parameters. Furthermore, efficient and accurate measurement of paper curl of individual sheets as they are being processed is difficult, so that information needed to define the setting of decurlers is not readily available. By contrast, a measure of paper curl of a stack being formed within an output device provides an averaging effect over multiple sheets, thus enabling a more reliable, less noisy estimate of the sheet curl level. In a similar fashion, a measure of paper curl of a stack being drawn from within an input device enables the feeding mechanism to make adjustments to preferentially feed curled sheets.
A reliable, efficient method to measure the degree of curl on the top of a paper stack is therefore important to make a sheet processing system less sensitive to the effects of paper curl.

Abstract: This probe lightly contacts the upper stack surface and detects sheet curl especially on the edge portions of the stack. The probe measures deviations of the surface as compared to a starting point defined on the terminal edge of the stack. The information provided by the probe is then fed to a user or controlled for transmission to a correcting apparatus.


A method and network element for marking data packets to be transmitted in a packet switched network with a priority information I, the packets being treated in the network according to the priority information I. The priority information I is calculated based on a required bit rate BSIO. The priority information I may be additionally calculated based on a nominal bit rate NBR and on a momentary bit rate MBR, such that a terminal device used with the network element is able to inform the network element in advance about the required bit rate.

In common communication networks, in particular in mobile communication networks two main techniques for a data transmission are used: circuit switched data transmission and packet switched data transmission.
In the circuit switched domain a network establishes a service connection for data transmission by allocating a (radio) channel to a terminal, e.g. a mobile station, when a network host or service provider intends to transmit data via the network. Then data is transmitted via the network after the connection has been established. The radio channel is occupied by the terminal during the entire duration of the connection, even though in many cases only a small amount of data has to be transmitted.
In the packet switched domain the network transmits a data packet only when required, i.e. when data transmission has to be carried out. Thus, several terminals can use the same channel at a time. If a terminal generates a data packet, the network routes that packet via a first unattached channel to a recipient. Thus, as data transmission frequently consists of data bursts, the channels can be used in an efficient manner. This type of packet switched data transmission is used in the Internet and e.g. GPRS (General Packet Radio Service) systems and UMTS (Universal Mobile Telecommunications System) systems.
Data packets are routed in packet switched networks via mostly unpredictable routes depending on the actual data traffic and depending on the configuration of the corresponding routers. Thus, packets may encounter different delays inside the network caused e.g. by variation in occupancy levels of queues inside the routers. Furthermore, as a result, the network capacity, in particular within certain routes, has to be divided between different glows (or connections, or customers).
The division of the capacity between the different flows is controlled by the so-called SIMA (Simple Integrated Media Access) system as being described in U.S. Pat. No. 6,047,326 and U.S. Pat. No. 6,081,505.
SIMA is a way to provide QoS (Quality of Service) using differentiated services, i.e. SIMA is a complete service and implementation solution. Differentiated services is an approach to provide QoS in the internet. The basic idea is to provide relative (soft) guarantees for delivery of IP (Internet Protocol) data packets. Complex functions are left at the edges of the network. This allows simple core network routers and ensures the scalability.
According to the SIMA concept each user or application shall define only two issues before a connection is established, namely a nominal bit rate (NBR) and the selection between real-time and non-real-time service classes. NBR forms the basic relationship between charging and QoS, and it defines how the network capacity is divided among different connections during overload situations. Due to the simplicity of SIMA the network operator does not guarantee the continuous availability of NBR. Furthermore, a user or application is allowed to send data with any bit rate independently of the NBR. The strength of SIMA is its wide area of applications. SIMA does not require to build complex systems with several service classes each appropriate to only certain applications.
The Idea of SIMA is that at the network edge packets are assigned a priority for a network domain. The packets are treated in the network domain according to the priority. The priority is depending on the ratio of a measured momentary bit rate (MBR) and NBR: If the MBR exceeds the NBR the priority is dropped and if the MBR is clearly below the NBR the priority is raised. Thereby, the NBR corresponds roughly to the bandwidth allocation for a given client.
Though the SIMA model as being described in U.S. Pat. No. 6,047,326 and U.S. Pat. No. 6,081,505 has been proved to be efficient and quite flexible, it has certain limitations. One of the limitations is that most of the application using the SIMA network are assumed to be adaptive in the sense that during overload situations they can reduce the bit rate, and correspondingly, if there is free capacity they can momentarily increase their bit rate. If that assumption is valid, the network capacity is divided proportional to the NBR for each flow. Due to this property, both the service provider and the customer may consider that the position of applications with constant (unchangeable) bit rate obtains worth service that what it should be.

Method, network element and terminal device for marking data packets


The invention comprises apparatus for use with atmospheric pressure ionization sources in which an aerosol is formed from a solution of a sample. The aerosol is received in a hollow member and discharged outside the chamber of the ionization source in order to reduce contamination of the ionization source itself by involatile material in the solution and by previously analysed samples. The hollow member is easily removable from the ionization source to facilitate cleaning and replacement. Ionization sources, mass spectrometers, and ion mobility spectrometers comprising the apparatus are also described.

Mass spectrometers are used to identify and quantitate compounds. Mass spectrometers analyse compounds by the mass to charge ratio of ions formed of the molecules of such compounds or the fragments of such molecules. Mass spectrometers generally have ion sources, which provide ions of the compounds for analysis. One form of ion source is an atmospheric pressure ionization (API) sources. An API source is, as its name suggests, an ion source that creates ions at approximately atmospheric pressure. These ions are directed to substantially closed sections of the mass spectrometer operating at low pressure or vacuum.
API sources suitable for generating ions from solutions include electrospray, atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) sources, all of which involve the formation of an aerosol from the solution. Electrospray sources form the aerosol by means of an electrical field created between an inlet capillary through which the solution is introduced and a counter electrode disposed downstream of the exit of the capillary. This electrical field also results in the ionization of at least some of a sample dissolved in the solution. APCI and APPI ion sources form the aerosol by means of a nebulizer, usually a concentric flow pneumatic nebulizer, and further comprise additional means for ionizing sample molecules comprised in the aerosol. These additional means may comprise a corona discharge (APCI sources) or a beam of photons (APPI sources). A nebulizer may also be used in electrospray sources to increase the maximum solution flow rate that the source can accept. Ionization may also be effected by a combination of some or all of the methods described.
API sources, which produce an aerosol comprising electrically charged droplets of the solution, are produced in a region containing gas at approximately atmospheric pressure. The charged droplets may comprise solvated ions characteristic of the sample dissolved in the solution. Droplets and solvated ions are sampled from the aerosol into a region of lower pressure through a small orifice or capillary tube, usually along a sampling axis inclined to the central axis of the aerosol. At least some of the ions entering the region of lower pressure are subsequently transmitted to a mass analyser through a sequence of vacuum chambers of progressively reducing pressure. These vacuum chambers usually comprise ion guides of various types. Mass analysers used in conjunction with these ion sources include linear quadrupoles, quadrupole, cylindrical and "Kingdon" ion trap analysers, magnetic sector analysers, ion cyclotron resonance analysers (ICR or FTMS analysers), time-of-flight analysers, or combinations of these analysers for use in tandem (MS/MS) apparatus. API ion sources are also used in ion mobility spectrometers, including field asymmetric ion mobility spectrometers (FAIMS) and in mass spectrometers comprising an ion mobility stage as well as more conventional mass filters or analysers. The charged droplets present in the aerosol may be at least partly desolvated through contact with gas molecules present in the atmospheric pressure region of the source. Desolvation may also be assisted by suitably directing (relative to the aerosol axis) gas flows into that region, and/or by heating the capillary, nebulizer and gas flows. Improved desolvation may also be obtained by heating the wall enclosing the atmospheric pressure region, particularly in the vicinity of the orifice through which ions may pass leave the source and pass into the mass analyser. Some prior sources also comprise means for flowing heated gas counter to the direction of travel of ions and droplets through the orifice.
Often, the solution admitted into API ionization sources is the eluent from a liquid chromatograph. Commonly used chromatographic flow rates are between 0.1 and 1.0 ml/min, but only a small fraction of the aerosol generated from the solution passes through the orifice into the region of lower pressure. The remainder of the aerosol is waste. Because the solvents (and samples) used for liquid chromatography may be poisonous, the atmospheric pressure region of an API source is usually enclosed. The chamber also serves to reduce contamination from material that may be present in the laboratory air causing interference to an analysis. As one or more flows of desolvation gas are introduced into the chamber, it must be fitted with an exhaust port through which gas and waste solvent can leave and be conducted to a safe discharge point.
Unfortunately, the majority of samples typically analysed with liquid chromatography are non-volatile, and the solvents employed often comprise non-volatile buffer salts. Because the majority of the spray does not enter the orifice, these non-volatile constituents tend to accumulate on surfaces within the atmospheric pressure enclosures, from which they may subsequently be released by contact with the aerosol to interfere with a subsequent analysis. They may also form insulating layers on electrically conducting surfaces within the chamber, which may become electrically charged and adversely affect the transport of ions into the orifice. In order to maintain performance, therefore, the atmospheric pressure chamber of prior API sources requires regular cleaning.
It is an object of the invention to provide API ionization sources and spectrometers, and apparatus for use in such ionization sources and spectrometers, in which the deposition of material on critical surfaces inside the sources is less than in prior sources. It is another object of the invention to provide API ionization sources, spectrometers and apparatus for use in such ionization sources and spectrometers that are more easily cleaned than are prior equipment. A further object of the invention is to provide apparatus for exhausting API ionization sources and spectrometers.
As used herein, "atmospheric pressure" includes the operation of an ion source in the presence of significant quantities of gas, perhaps with pressures several hundred torr either side of atmospheric pressure itself. The term is generally used in the art to distinguish this type of ionization source from those that operate under high or medium vacuum, for example, electron impact or chemical ionization sources. Further, the term "charged particles" is meant to include singly- and multiply-charged ions, solvated ions, adduct ions, and cluster ions, etc, all formed from a sample in an ionization source operating at atmospheric pressure (as defined above), and also charged droplets of solvent comprising molecules or ions characteristic of a sample.

Device, apparatus and methods for mass spectrometry


A rolling cone drill bit is provided that has gage inserts on the first row from the bit axis to cut to full gage diameter that have a cutting portion enhanced with a layer of super abrasive material. The gage cutting surface has a center axis that is canted to be more normal to the gave curve such that its point of contact at gage is away from the thinner portion of the layer of super abrasive material.

The present invention relates generally to diamond enhanced inserts for use in drill bits and more particularly to diamond enhanced inserts for use in the gage or near-gage rows of rolling cone bits. Still more particularly, the present invention relates to placement of a diamond coating on an insert and to positioning the insert in a cone such that wear and breakage of the insert are reduced and the life of the bit is enhanced.
An earth-boring drill bit is typically mounted on the lower end of a drill string and is rotated by rotating the drill string at the surface or by actuation of downhole motors or turbines, or by both methods. With weight applied by the drill string, the rotating drill bit engages the earthen formation and proceeds to form a borehole along a predetermined path toward a target zone. The borehole formed in the drilling process will have a diameter generally equal to the diameter or "gage" of the drill bit.
A typical earth-boring bit includes one or more rotatable cutters that perform their cutting function due to the rolling movement of the cutters acting against the formation material. The cutters roll and slide upon the bottom of the borehole as the bit is rotated, the cutters thereby engaging and disintegrating the formation material in its path. The rotatable cutters may be described as generally conical in shape and are therefore sometimes referred to as rolling cones. Such bits typically include a bit body with a plurality of journal segment legs. Each rolling cone is mounted on a bearing pin shaft that extends downwardly and inwardly from a journal segment leg. The borehole is formed as the gouging and scraping or crushing and chipping action of the rotary cones remove chips of formation material that are carried upward and out of the borehole by drilling fluid that is pumped downwardly through the drill pipe and out of the bit. The drilling fluid carries the chips and cuttings in a slurry as it flows up and out of the borehole. The earth disintegrating action of the rolling cone cutters is enhanced by providing the cutters with a plurality of cutter elements.
The cost of drilling a borehole is proportional to the length of time it takes to drill to the desired depth and location. The time required to drill the well, in turn, is greatly affected by the number of times the drill bit must be changed in order to reach the targeted formation. This is the case because each time the bit is changed, the entire string of drill pipe, which may be miles long, must be retrieved from the borehole, section by section. Once the drill string has been retrieved and the new bit installed, the bit must be lowered to the bottom of the borehole on the drill string, which again must be constructed section by section. As is thus obvious, this process, known as a "trip" of the drill string, requires considerable time, effort and expense. Accordingly, it is always desirable to employ drill bits that will drill faster and longer and are usable over a wider range of formation hardnesses.
The length of time that a drill bit may be employed before it must be changed depends upon its rate of penetration ("ROP"), as well as its durability or ability to maintain an acceptable ROP. The form and positioning of the cutter elements on the cutters greatly impact bit durability and ROP and thus are critical to the success of a particular bit design.
Bit durability is, in part, measured by a bit's ability to "hold gage," meaning its ability to maintain a full gage borehole diameter over the entire length of the borehole. Gage holding ability is particularly vital in directional drilling applications. If gage is not maintained at a relatively constant dimension, it becomes more difficult, and thus more costly, to insert drilling assemblies into the borehole than if the borehole had a constant full gage diameter. For example, when a new, unworn bit is inserted into an undergage borehole, the new bit will be required to ream the undergage hole as it progresses toward the bottom of the borehole. Thus, by the time it reaches the bottom, the bit may have experienced a substantial amount of wear that it would not have experienced had the prior bit been able to maintain full gage. This unnecessary wear will shorten the bit life of the newly-inserted bit, thus prematurely requiring the time-consuming and expensive process of removing the drill string, replacing the worn bit, and reinstalling another new bit downhole.
Cutter elements are generally of two types: inserts formed of a very hard material, such as tungsten carbide, that are press fit into undersized apertures in the cone surface; or teeth that are milled, cast or otherwise integrally formed from the material of the rolling cone. Bits having tungsten carbide inserts are typically referred to as "TCI" bits, while those having teeth formed from the cone material are known as "milled tooth bits." In each case, the cutter elements on the rotating cutters functionally breakup the formation to form new borehole by a combination of gouging and scraping or chipping and crushing. While the present invention has primary application in bits having inserts rather than milled teeth and the following disclosure is given in terms of inserts, it will be understood that the concepts disclosed herein can also be used advantageously in milled tooth bits.
To assist in maintaining the gage of a borehole, conventional rolling cone bits typically employ a heel row of hard metal inserts on the heel surface of the rolling cone cutters. The heel surface is a generally frustoconical surface and is configured and positioned so as to generally align with and ream the sidewall of the borehole as the bit rotates. The inserts in the heel surface contact the borehole wall with a sliding motion and thus generally may be described as scraping or reaming the borehole sidewall. The heel inserts function primarily to maintain a constant gage and secondarily to prevent the erosion and abrasion of the heel surface of the rolling cone. Excessive wear of the heel inserts leads to an undergage borehole, decreased ROP, increased loading on the other cutter elements on the bit, and may accelerate wear of the cutter bearing and ultimately lead to bit failure.
In addition to the heel row inserts, conventional bits typically include a gage row of cutter elements mounted adjacent to the heel surface but orientated and sized in such a manner so as to cut the corner of the borehole. In this orientation, the gage cutter elements generally are required to cut both the borehole bottom and sidewall. The lower surface of the gage row insert engages the borehole bottom while the radially outermost surface scrapes the sidewall of the borehole. Conventional bits also include a number of additional rows of cutter elements that are located on the cones in rows disposed radially inward from the gage row. These cutter elements are sized and configured for cutting the bottom of the borehole and are typically described as inner row cutter elements.
Differing forces are applied to the cutter elements by the sidewall than the borehole bottom. Thus, requiring gage cutter elements to cut both portions of the borehole compromises the cutter design. In general, the cutting action operating on the borehole bottom is typically a crushing or gouging action, while the cutting action operating on the sidewall is a scraping or reaming action. Ideally, a crushing or gouging action requires a tough insert, one able to withstand high impacts and compressive loading, while the scraping or reaming action calls for a very hard and wear resistant insert. One grade of cemented tungsten carbide cannot optimally perform both of these cutting functions as it cannot be as hard as desired for cutting the sidewall and, at the same time, as tough as desired for cutting the borehole bottom. Similarly, PCD grades differ in hardness and toughness and, although PCD coatings are extremely resistant to wear, they are particularly vulnerable to damage caused by impact loading as typically encountered in bottom hole cutting duty. As a result, compromises have been made in conventional bits such that the gage row cutter elements are not as tough as the inner row of cutter elements because they must, at the same time, be harder, more wear resistant and less aggressively shaped so as to accommodate the scraping action on the sidewall of the borehole.
In FIG. 14 the positions of all of the cutter inserts from all three cones are shown rotated into a single plane. As shown in FIG. 14, to assist in maintaining the gage of a borehole, conventional rolling cone bits typically employ a row of heel cutters 214 on the heel surface 216 of each rolling cone 212. The heel surface 216 is generally frustoconical and is configured and positioned so as to generally align with the sidewall of the borehole as the bit rotates. The heel cutters 214 contact the borehole wall with a sliding motion and thus generally may be described as scraping or reaming the borehole sidewall. The heel cutters 214 function primarily to maintain a constant gage and secondarily to prevent the erosion and abrasion of the heel surface of the rolling cone.
In addition to heel row cutter elements, conventional bits typically include a row of gage cutter elements 230 mounted in gage surface 231 and oriented and sized in such a manner so as to cut the corner of the borehole. For purposes of the following discussion, the gage row is defined as the first row of inserts from the bit axis of a multiple cone bit that cuts to full gage. This insert typically cuts both the sidewall of the borehole and a portion of the borehole floor. Cutting the corner of the borehole entails cutting both a portion of the borehole side wall and a portion of the borehole floor. It is also known to accomplish the corner cutting duty that is usually performed by the gage cutters by dividing it between adjacent gage and nestled gage cutters (not shown) such that the nestled gage cutters perform most of the sidewall cutting and the adjacent gage cutters cut the bottom portion of the corner.
Conventional bits also include a number of additional rows of cutter elements 232 that are located on the main, generally conical surface of each cone in rows disposed radially inward from the gage row. These inner row cutter elements 232 are sized and configured for cutting the bottom of the borehole and are typically described as inner row cutter elements.
In FIGS. 14, 16, 18 20 and 22, the positions of all of the cutter inserts from all three cones are shown rotated into a single plane. As can be seen, the cutter elements in the heel and gage rows typically share a common position across all three cones, while the cutter elements in the inner rows are radially spaced so as to cut the borehole floor in the desired manner. Excessive or disproportionate wear on any of the cutter elements can lead to an undergage borehole, decreased-ROP, or increased loading on the other cutter elements on the bit, and may accelerate wear of the cutter bearing and ultimately lead to bit failure.
Relative to polycrystalline diamond, tungsten carbide inserts are very tough and impact resistant, but are vulnerable to wear. Thus, it is known to apply a cap layer of polycrystalline diamond (PCD) to each insert. The PCD layer is extremely wear-resistant and thus improves the life of a tungsten carbide insert. Conventional processing techniques have, however, limited the use of PCD coatings to axisymmetrical applications. For example, a common configuration for PCD coated inserts can be seen in FIGS. 14 and 15, wherein insert 230 comprises a domed tungsten carbide base or substrate 240 supporting a hemispherical PCD coating 242. Inserts of this type are formed by forming a non-reactive container also known as a "can", corresponding to the external shape of the insert, positioning a desired amount of PCD powder in the can, placing the substrate in the can on top of the PCD powder, enclosing and sealing the can, and applying sufficient pressure and temperature to sinter the PCD and adhere it to the substrate. If required, the resulting diamond or substrate layers can be ground into a final shape following demolding.
The shape of PCD layers formed in this manner is based on consideration of several factors. First, the difference in the coefficients of thermal expansion of diamond and tungsten carbide gives rise to differing rates of contraction as the sintered insert cools. This in turn causes residual stresses to exist in the cooled insert at the interface between the substrate and the diamond layer. If the diamond layer is too thick, these residual stresses can be sufficient to cause the diamond layer to break away from the substrate even before any load is applied. On the other hand, if the diamond layer is too thin, it may not withstand repetitive loading during operation and may fail due to fatigue. The edge 261 of the diamond coating is a particular source of stress risers and is particularly prone to failure.
For all of these reasons, PCD coated inserts have typically been manufactured with a hemispherical top, commonly referred to as a "semi-round top" or SRT. Referring again to FIG. 15, the SRT 303 is aligned with the longitudinal axis 241 of the substrate such that its center point lies approximately on axis 241. The inner surface of the diamond coating corresponds to the domed shape of the substrate. Thus, the thickness of the diamond coating is greatest on the axis of the insert and decreases toward the edge of the coating layer. While inserts in which the diamond coating is of uniform thickness are known, e.g. U.S. Pat. No. 5,030,250, it is more common to form a diamond layer that decreases in thickness as distance from the center point increases, resulting in the crescent-shaped cross-section shown in FIG. 15. Nevertheless, it is contemplated that diamond layer 242 can be other than crescent-shaped. For example, the thickest portion of diamond layer 242 could comprise a region rather than a point. The diamond layer typically tapers toward the outer diameter of the substrate (the diamond edge 261). This tapering helps prevent cracks that have been known to develop at the diamond edge when a substantially uniform diamond layer is used.
Because of the interrelationship between the shape of each cone and the shape of the borehole wall, cutter elements in the heel row and inner rows are typically positioned such that the longitudinal axes of those cutter elements are more or less perpendicular to the segment of the borehole wall (or floor) that is engaged by that cutter element at the moment of engagement. In contrast, cutter elements in the gage row do not typically have such a perpendicular orientation. This is because in prior art bits, the gage row cutter elements are mounted so that their axes are substantially perpendicular to the cone axis 213. Mounted in this manner, each gage cutter element engages the gage curve 222 at a contact point 243 (FIG. 15) that is close to the thin edge of the diamond coating on the hemispherical top of each cutter element.
Still referring to FIG. 15, the angle between the insert axis 241 and a radius terminating at contact point 243 is hereinafter designated a. In prior art bits, the angle α has typically been in the range of 54° to 75°, with a being greater for harder formation types. For example, in a typical 12¼″ rock bit, α may be about 57°.
The prior art configuration described above is not satisfactory, however, because contact point 243 is at the edge of diamond layer 242, where the diamond layer is relatively thin, and is subjected to particularly high stresses and is therefore especially vulnerable to cracking and breaking, which in turn leads to premature failure of the inserts in the gage row.
Accordingly, there remains a need in the art for a gage insert that is more durable than those conventionally known and that will yield greater ROP's and an increase in footage drilled while maintaining a full gage borehole. Preferably, the gage insert would also be relatively simple to manufacture.

Cutting elements of gage row and first inner row of a drill bit


The present invention provides a process for the hardening treatment of sintered members which can impart sufficient wear resistance thereto at low cost without causing a reduction in dimensional accuracy due to heat distortion. This process for the hardening treatment of sintered members comprises the steps of coating an iron-based sinterable member with a Nixe2x80x94P alloy powder containing 7 to 13% by weight of phosphorus so as to give a coating weight of 0.1 to 1.2 mg/mm2; sintering the iron-based sinterable member coated with the Nixe2x80x94P alloy powder at a temperature in the range of 1,000 to 1,300xc2x0 C.; and hardening the iron-based sintered member by cooling it at a cooling rate of not less than 10xc2x0 C./min. until a temperature of 200xc2x0 C. is reached.

1. Field of the Invention
This invention relates to a process for the hardening treatment of sintered members which can harden all or part of an iron-based sintered member without producing any heat distortion, and can thereby improve its wear resistance.
2. Description of the Related Art
Conventionally, synchronizing hubs which are iron-based sintered parts are frequently used in the transmissions of four-wheeled motor vehicles. Since these synchronizing hubs come into face contact with counter parts, they are required to have high wear resistance. In the case of such parts requiring wear resistance, it has been conventional practice to subject sintered parts to a thermal refining treatment comprising quenching and tempering, induction hardening, impregnation treatment (also known as an infiltration treatment) or the like and thereby improve the hardness and wear resistance thereof.
However, the above-described conventional hardening processes have the following problems.
1) Since the thermal refining treatment is carried out by heating a whole sintered member and cooling it rapidly, the sintered member may undergo a heat distortion. Consequently, it has been difficult to obtain high dimensional accuracy stably.
2) Induction hardening has the advantage that the sintered member retains high dimensional accuracy. However, the induction hardening equipment is expensive. Moreover, separate hardening coils are required for different types of sintered members, so that treating costs may be increased because of limited flexibility. Thus, induction hardening has the disadvantage that the overall cost is high.
3) The impregnation treatment is a method in which another infiltration metal is melted and infiltrated into a sintered member to fill the pores of the sintered member and thereby improve the strength and toughness thereof. To this end, powdered copper is usually used as the infiltration metal. However, it has been impossible to achieve sufficient wear resistance.
4) Another process is to harden a sintered member by modifying the composition of a sinterable powder mixture or allying it. However, since this process involves tempering or cementation hardening, a heat distortion may be produced. Consequently, it has been difficult to obtain high dimensional accuracy stably.
An object of the present invention is to solve the above-described problems by providing a process for the hardening treatment of sintered members which can impart sufficient wear resistance thereto at low cost without causing a reduction in dimensional accuracy due to heat distortion.
In order to accomplish the above object, the present invention provides a process for the hardening treatment of sintered members which comprises the steps of compacting an iron-based sinterable powder mixture to form a compact; coating the compact with a coating material comprising a Nixe2x80x94P alloy powder containing 7 to 13% by weight of phosphorus so as to give a coating weight of at least 0.1 mg/mm2; sintering the compact coated with the Nixe2x80x94P alloy powder to produce an iron-based sintered member; and hardening the iron-based sintered member by cooling it.
In the above-described hardening treatment process, the coating material applied to the compact comprises a powder, so that the coating material can be easily applied and used for purposes of local treatment. Moreover, since the aforesaid coating material comprises a Ni alloy, the heat of sintering causes the coating material to penetrate into the compact and diffuse into its iron matrix to form a solid solution, and the subsequent cooling step can transform the iron matrix into a martensitic structure and thereby form a hardened layer. This martensitic structure is a very hard metallographic structure and can hence improve the wear resistance of the sintered member. Moreover, since the coating material contains 7 to 13% by weight of P, this P penetrates and diffuses deeper into the compact, so that a hard steadite structure (Fe3P) is precipitated to form a hardened layer and thereby improve the wear resistance of the sintered member. The thickness of the hardened layer can be controlled by varying the coating weight of the coating material.
In the process for the hardening treatment of sintered members in accordance with another embodiment of the present invention, the aforesaid coating material is applied so as to give a coating weight of 0.1 to 1.2 mg/mm2, the aforesaid sintering is carried out at a temperature in the range of 1,000 to 1,300xc2x0 C., and the aforesaid cooling is carried out at a cooling rate of not less than 10xc2x0 C./min. until a temperature of 200xc2x0 C. is reached.
Since the aforesaid sintering temperature is in the range of 1,000 to 1,300xc2x0 C., the compact can be treated in a conventional sintering furnace without requiring special equipment or high costs.
The process for the hardening treatment of sintered members in accordance with the present invention can impart high wear resistance thereto at low cost without producing any heat distortion.

Process for the hardening treatment of sintered members


An objective lens actuator comprises a lens holder for attaching an objective lens thereon, a piece of focusing coil, being wound along side surface of the lens holder around the objective lens, and three magnets, being disposed opposing to two surfaces each having a normal line perpendicular to both a focusing direction and a tracking direction, among four side surfaces of the lens holder, wherein the three magnets are aligned, continuously, along the tracking direction, differing a polarity thereof from one another, and width of the magnets on both outsides is wider than width of the magnet inside, or alternately, one magnet, being disposed opposing to two surfaces each having a normal line perpendicular to both a focusing direction and a tracking direction, among four side surfaces of the lens holder, wherein the magnet is magnetized into three poles along the tracking direction, and among the three poles, width of the poles on both outsides is wider than width of the pole inside.

The present invention relates to an objective lens actuator, for fitting a focus position of an objective lens upon an target track on a recording surface of an optical disc, with driving the objective lens into a focusing direction and a tracking direction, so as to conduct reproducing or recording of information, which is recorded on the recording surface of the optical disc, and also a disc apparatus applying the same therein.
With the disc apparatus for recording information onto a disc-like information recording medium, or for reproducing the information recording thereon, an improvement of data transfer rate is achieved by rotating the optical disc with high speed. In the disc apparatus is mounted an objective lens actuator for driving the objective lens into the focusing direction and the tracking direction, so as to record and reproduce the information, correctly, with following a track on the optical disc.
In general, such objective lens actuator is constructed with a magnetic circuit, including a yoke and a permanent magnet, a moving portion including an objective lens and a driving coil attached therewith, a stationary or fixed portion for holding this moving portion thereon, and supporting members for elastically supporting the moving portion, which is connected with the fixed portion. When current flows through a focusing coil, within the magnetic field produced by the magnetic circuit including the yoke and the permanent magnet, then an electro-magnetic force is generated, and thereby the moving portion is driven into the focusing direction. In the similar manner, when current flows through a tracking coil, within the magnetic field produced by the magnetic circuit including the yoke and the permanent magnet, then an electro-magnetic force is generated, and thereby the moving portion is driven into the tracking direction.
For such the objective lens actuator, the following three (3) characteristics are required, mainly. First of all, for achieving a high accuracy positioning control while suppressing deflections due to disturbances, such as, wobbling and/or eccentricity of the disc, etc., it is necessary to increase driving sensitivity to be high. Next, for increasing control band fitting to high-speed of rotation number of the optical disc, it is necessary to bring amplitude to be small, at high-order resonance frequency of an elastic deformation mode of the moving portion. And, for dealing with high density while suppressing an aberration, which will be a cause of signal deterioration, it is necessary to reduce the tilt of the objective lens.
Among of those, in particular, relating to the driving sensitivity, there is already known an objective lens actuator, wherein a magnet is constructed with a first wide-width magnetic pole located at a center along the tracking direction, and second magnetic poles on both sides thereof, putting the first magnetic pole between them, and two (2) sides of the tracking coils provided in plural numbers thereof, on an inner side and an outer side thereof, are attached, opposing to the first magnetic pole and the second magnetic pole, respectively, thereby winding one (1) piece of the focusing coil around a peripheral side surface of the moving portion, and also a boundary portion between the magnetic poles of the magnet is disposed outside than the both side edges of the yoke (an example shown in the following Patent Document 1). With this, in the focusing direction, it is possible to increase a number of magnetic fluxes crossing the focusing coil, and also in the tracking direction, it is possible to generate driving forces on both sides, i.e., an inner side and an outer side of each tracking coil; thereby achieving an improvement of the driving sensitivity.
[Patent Document 1] Japanese Patent Laying-Open No. 2005-38496 (2005) (Claim 1 and FIG. 2).

Objective lens actuator and a disc apparatus applying the same therein


A liquid container includes: a bubble trapping section, disposed upstream of the upstream buffer chamber. The bubble trapping section includes: a bubble trapping chamber, adapted to trap bubbles upside by allowing the liquid level to be lowered with reduction in an amount of remaining liquid at a time of consuming the liquid; an inlet, communicating at a vertical upper position of the bubble trapping chamber to introduce the liquid at the time of consuming the liquid; and an outlet, communicating at a vertical lower position of the bubble trapping chamber to discharge the liquid at the time of consuming the liquid.

1. Technical Field
The present invention relates to a liquid container suitable for detecting an amount of remaining liquid (ink) in a liquid consuming apparatus such as an inkjet printing apparatus and a method of manufacturing the liquid container.
2. Related Art
As a representative example of a liquid consuming apparatus, there is an inkjet printing apparatus having an inkjet print head for printing an image. Other liquid ejecting apparatuses may include an apparatus having a coloring material ejecting head used for manufacturing a color filter and the like of a liquid crystal display, an apparatus having an electrode material (conductive paste) ejecting head used for forming electrodes of an organic EL display, a field emission display (FED), and the like, an apparatus having a biological organic material ejecting head used for manufacturing a bio chip, and an apparatus having a sample ejecting head as a precise pipette.
In the inkjet printing apparatus as the representative example of the liquid consuming apparatus, an inkjet print head having a pressure generator pressurizing a pressure generating chamber and nozzle orifices ejecting the pressurized ink as ink droplets is mounted on a carriage. By endlessly supplying the ink in an ink container to the print head through a flow channel, a printing operation can be continuously performed. The ink container is constructed as a detachable cartridge that can be replaced by a user when the ink is completely consumed.
There is a method of managing ink consumption by integrating the number of ink droplets emitted from the print head or the amount of ink sucked in maintenance by software or a method of managing when the ink is actually consumed by a predetermined amount by attaching a liquid level detecting electrode to the ink cartridge, as a method of managing the ink consumption of an ink cartridge.
However, the method of managing the ink consumption by integrating the number of ejected ink droplets or the amount of ink by software causes the following problem. The head may eject ink droplets with non-uniformity in weight. The non-uniformity in weight of the ink droplets does not affect the image quality but the ink with a margin is filled in the ink cartridge in consideration of accumulation of errors in ink consumption due to the non-uniformity. Accordingly, there is a problem that the ink corresponding to the margin remains in some apparatuses.
On the other hand, in the method of managing when the ink is consumed by the use of an electrode, since the actual amount of remaining ink can be detected, it is possible to manage the amount of remaining ink with high reliability. However, since the detection of the ink level depends on the conductivity of the ink, the kinds of ink detectable are limited, thereby complicating the sealing structure of the electrode. Since precious metals with excellent conductivity and anti-corrosion are usually used as the material of the electrode, the cost for manufacturing the ink cartridge is enhanced. Since two electrodes should be necessarily formed, the number of manufacturing processes increases, thereby increasing the manufacturing cost.
Therefore, to solve the above-mentioned problems, a piezoelectric device (herein, referred to as a sensor unit) is disclosed in JP-A-2001-146030. The sensor unit monitors the amount of ink remaining in the ink cartridge by the use of the resonance frequency of a residual vibration signal resulting from the residual vibration (free vibration) of a vibrating plate after forcible vibration when the ink remains and does not remain in a sensor cavity opposed to the vibrating plate having a piezoelectric element formed thereon.
In FIG. 8 of JP-A-2006-248201, plural vertical-direction changing portions changing the flow of ink in vertical directions are shown. The space above the vertical-direction changing portions serves as a bubble trapping space.
In FIGS. 9 and 14 of JP-A-2006-315302, a structure supporting a sensor base at three positions of a partition wall and both main case walls thereof is shown. In JP-A-2001-328277, a barrier wall is disposed in the liquid opposed to the sensor, whereby bubbles hardly enter the sensor cavity even when the bubbles are formed in the liquid level in the tank.
Techniques of securing a bypass channel of a liquid by not welding a part of a film covering an opening of a liquid passage and then closing the bypass channel of the liquid by welding the part of the film are disclosed in JP-A-2005-022257 and JP-A-2004-306466.
The technique disclosed in JP-A-2006-248201 employs a specific gravity separation method of trapping bubbles having small specific gravity in the upside by the use of a labyrinth channel on the basis of a difference in specific gravity between the liquid and the bubbles.
Here, as shown in FIG. 8 of JP-A-2006-248201, the ink is introduced from the lower position of the bubble trapping space and the ink is discharged from the lower position of the bubble trapping space. In this case, as described later, when the ink consumption rate is great due to a continuous printing operation and thus the ink flow rate is great, the bubbles in the bubble trapping space are sucked into the ink and discharged along with the ink in the vicinity of the ink end. Then, bubbles are formed in the buffer chamber in the just upstream side of the sensor cavity and the bubbles are detected by the sensor, thereby falsely detecting the ink end.
In the technique disclosed in JP-A-2006-315302, the vibration of the piezoelectric element is absorbed by the main case coming in contact with the sensor base at three positions, thereby making it difficult to satisfactorily guarantee the vibration being detectable by the piezoelectric element. Since the sensor base is positioned in an opening formed in the main case, bubbles may stay in minute gaps around the sensor base at the time of injecting the ink, thereby causing false detection of the ink end. This problem is not prevented even by the use of the barrier wall shown in JP-A-2001-328277. This is because the barrier wall hinders the flow of ink at the time of initially injecting the ink to easily generate bubbles around the sensor base.

Liquid container and method of manufacturing the same


A magneto-optical recording method is disclosed, by which a magnetic recording pattern is formed in an overwriting mode, utilizing demagnetizing field, by directing a light beam onto a perpendicularly magnetized film layer of a magneto-optical recording medium, wherein when recording is being carried out by the application of a light beam onto the perpendicularly magnetized film layer, on switching the direction of magnetization for recording from downward to upward or from upward to downward, when required, with respect to the surface of the magnetized film layer, a light beam application mode for a light-beam applied portion in the magnetized film layer to which the light beam has been applied, and a light beam application mode in a portion in the magnetized film layer immediately after the light-beam applied portion to which the light beam is yet to be applied, are changed.

1. Field of the Invention
The present invention relates to a magneto-optical recording method, and more particularly to a magneto-optical recording method capable of performing overwriting.
2. Discussion of Background
In recent years, the development of magneto-optical recording has proceeded actively because this method is capable of recording higher volumes of information than conventional magnetic recording and the like, and because rewriting of the information is possible. Some of these developments are already on the market. However, with many of the magneto-optical recording apparatus now on the market, when information is written, it is necessary to first erase the original information, then write in the new information. Considerable time is wasted in making this erasure.
Although many different magneto-optical recording methods in which overwriting is possible have been proposed, they have not been used in practice because of a number of problems.
The following magneto-optical recording methods are conventionally known:
(1) A general light modulation system (for example, described in Applied Magnetics Association Journal Vol. 8. No. 5 (1984)). PA0 (2) An overwrite system by varying light intensity using a two-layered film (for example, described in Applied Magnetics Research Association Data 55-15 (1988)). PA0 (3) A magnetic field modulation system utilizing a fixed magnet (for example, described in Electrical Society Magnetics Research Association Data MAG-86-96)). PA0 (4) A magnetic field modulation system utilizing a floating head (for example, described in Electrical Society Magnetics Research Association Data MAG-87-178(1987), Japanese Laid-Open Patent Application 63-204532 and Japanese Laid-Open Patent Application 63-217548)). PA0 (5) An overwrite system utilizing a magnetic head with a resonance circuit and a pulsed laser (for example, described in IEEE Trans. Magn. 24, P.666 (1988) and Japanese Laid-Open Patent Application 63-37842). PA0 (6) A system utilizing demagnetizing field (Han-Ping D. Shieh and Mark H. Kryder, Appl. Phys. Lett. 49(1985) 473; Han-Ping D. Shieh and Mark H. Kryder, IEEE Trans. Magn., Vol. MAG-23(1987)171; M. D. Schultz, H-P.D. Shieth and M. H. Kryder, J. Appl. Phys. 63 (1988)3844).
An analysis of the systems listed above shows that: with the light modulation system (1), it is generally impossible to overwrite unless an erasure operation is first performed, with the attendant problem that considerable time is required for rewriting.
With the overwrite system (2) by varying light intensity, using a two-layered film, the recording layer becomes complex in structure, so that the fine adjustment of the exchange bonding between the two layers is very difficult, and a large magnetic field is necessary for initialization. The problem therefore arises that a large expensive magnet must be used for initialization so that the size of the apparatus increases. Furthermore, the difference in power between the light beams with "1" and "0" during recording is so small that the respective allowable differences are restricted, so that the recording becomes unstable.
With the magnetic field modulation system (3), utilizing a fixed magnet, a large magnet is required and the amount of power consumed is therefore large. It is also extremely difficult to conduct high speed recording, and it is generally agreed that this system is restricted to digital recording at about 1 MHz.
With the magnetic field modulation system (4), utilizing a floating head, the magnetic head almost touches the optical recording disk medium so that the advantage of avoiding contact with the optical disk medium is essentially lost. Furthermore, there is the necessity for forming the medium in the form of a single plate, which causes problems with the volume of memory and in protection of the substrate and the magnetic layer formed thereon.
The overwrite system (5) utilizing a magnetic head with a resonance circuit and a pulsed laser is better than the above-mentioned magnetic field modulation system (3), but exhibits the same type of problems.
With the system (6) utilizing demagnetizing field, the laser pulse must be precisely directed at the position of the previously recorded bit, therefore control of positioning of the laser pulse is difficult. Another problem is the fact that recording can take place only at these bit positions.

Magneto-optical recording method with switching and maintaining perpendicular magnetization light beam application modes


A detector for a coaxial bipolar time-of-flight mass spectrometer is described. The detector includes a microchannel plate, a scintillator disposed in parallel relation to said microchannel plate, and a mirror oriented at an angle relative to said scintillator. The angle of the mirror is selected to reflect photons given off by the scintillator in a direction substantially orthogonal to the scintillator. The microchannel plate, the scintillator, and the mirror each have an opening formed centrally therein. The detector according to this aspect of the invention also includes a transparent tube extending through the central openings formed in each of the microchannel plate, the scintillator, and the mirror. A photomultiplier tube is coupled to the detector for receiving photons reflected by the mirror. A coaxial bipolar time-of-flight mass spectrometer incorporating the detector is also described.

Mass spectrometers can be used in a wide variety of applications in medical, food processing, environmental monitoring, and space exploration. Time-of-flight mass spectroscopy has become the most widely used technique for identifying very large organic molecules. This technique has become the method of choice for most drug discovery and polymer applications. The time-of-flight technique is frequently chosen because it is the only technique capable of the high mass sensitivity needed for many substances.
The time-of-flight mass spectrometry (TOF-MS) technique is a known technique which has seen resurgence in popularity because of cost reductions in electronics and the advent of high temporal resolution detectors. The availability of high temporal resolution detectors has enabled shorter flight tubes to be used, which leads to smaller vacuum systems and lower overall instrument costs. These designs are particularly well suited for use in portable instruments.
Three types of electron multipliers have been used in time-of-flight mass spectrometers (TOF-MS): single channel electron multipliers (SCEM's), discrete dynodes (DD's), and micro channel plates (MCP's). Single channel electron multipliers are no longer used in modern instruments because of their limited temporal resolution (20–30 ns at FWHM) and dynamic range. Discrete dynode electron multipliers exhibit good dynamic range, but are used in moderate and low resolution applications because they provide relatively poor pulse widths (typically, 6–10 ns at FWHM).
MCP-based detectors are used in virtually all high resolution applications because they provide the highest temporal resolution (400 ps at FWHM). In order to preserve the high temporal resolution of MCP-based detectors it is necessary to use a 50 ohm impedance-matched anode and transmission line. Fifty ohm impedance-matched anodes are conical in shape and are typically terminated with an SMA or BNC connector.
In the operation of a typical linear MALDI TOF instrument, analyte molecules, dispersed among matrix material of a sample 11 are ionized by a nitrogen laser 13 as shown in FIG. 1. The resultant ions are held (delayed extraction) and then ejected down a flight tube by the application of high voltage pulses. Mass separation occurs during the flight (typically about 1 meter) to the detector 15, with the lower mass ions 17 arriving first, followed by progressively larger mass ions 19. Upon arrival of an ion at the detector 15, the electron multiplier 21 produces a charge pulse corresponding to the arrival time of each ion as shown by the trace in FIG. 2. A high speed digitizer is then used to record the arrival times of the ions, from which the mass of the ion can be determined.
A second type of time-of-flight instrument utilizes an ion mirror to enable the ions to traverse the flight tube twice, thereby increasing the separation distance (and time) of ions with differing masses. FIG. 3 illustrates a typical reflectron-type time-of-flight mass filter. In operation, ions 31a–31e of various masses are injected into a pusher plate assembly 33 and then ejected orthogonally into the flight tube 35 by the application of a high voltage pulse. The ions then travel to the ion mirror or reflectron lens 37 which reverses their direction and directs the ions to the detector 39 located approximately the same distance from the ion mirror 37 as the ion source. In this arrangement the ions travel approximately twice the distance as in the other types of detectors. Thus, they separate twice as far from each other in time and space without substantially increasing the size of the vacuum system.
A third time-of-flight spectrometer configuration is also known. This geometry, known as co-axial time-of-flight, combines the vacuum chamber simplicity of the linear time-of-flight construction with the enhanced mass resolution provided by the reflectron geometry. FIG. 4 illustrates a coaxial time-of-flight mass spectrometer arrangement. In the coaxial time-of-flight spectrometer, the ions are created behind the detector plate and the microchannel plate and launched into the linear flight tube through center holes in the detector plate and the microchannel plate. A special ion mirror reflects the ions back to the detector. The ion mirror causes the ions to fan out radially in order to impact the active area of the MCP at the end of their return flight.
Despite the simplicity and low cost advantages of the coaxial time-of-flight geometry, instrument designers have largely abandoned this geometry because high temporal resolution detectors could not be produced. MCP based detectors with center holes have been used for scanning electron microscopes (SEMs) and focused ion beam (FIB) applications for many years. Such detectors were also used in early time-of-flight instruments as co-axial TOF detectors. The drawback of the previous design detectors in modern instruments is that the flat metal anodes used to collect the resultant charge from the MCP in response to ion impacts, produced a pulse with a severe ring which lasted several nanoseconds in duration, rendering the known detectors unusable for high resolution TOF mass spectrometry. The detector according to the present invention is a high temporal resolution coaxial time-of flight detector that has been developed to overcome the deficiencies in the known detectors.

Detector for a co-axial bipolar time-of-flight mass spectrometer


The present invention relates to a granular thermal insulation material comprising hydrophobized silicon dioxide and at least one IR opacifier, having a tamped density of up to 250 g/l and a compressive strength according to DIN EN 826:2013 at 50% compression of 150 to 300 kPa or greater than 300 kPa, to processes for production thereof and to the use thereof for thermal insulation.

Effective thermal insulation of houses, industrial plants, pipelines and suchlike is an important economic problem. The majority of insulation materials based on organic substances, such as polyurethane foams, are combustible and only usable at restricted temperatures. These disadvantages are not exhibited by the hitherto less widespread thermal insulation materials based on inorganic oxides, for example highly porous silicon dioxide. In the case of use of such materials for thermal insulation, by contrast, the optimization of the mechanical properties, for example particle size and mechanical stability, plays a major role.
Such silicon dioxide-based thermal insulation materials are typically based on what are called the aerogels, and also precipitated or fumed silicas. More detailed information relating to these silica types can be found in Ullmann's Encyclopedia of Industrial Chemistry, "Silica" chapter, published online on Apr. 15, 2008, DOI: 10.1002/14356007.a23_583.pub3.
WO 2006/097668 A1 discloses a granular thermal insulation material comprising hydrophobic fumed silicon dioxide and an opacifier, which is produced by mixing a hydrophobic silicon dioxide with opacifier and subsequent densification to give granules having a size of 0.25 to 2.5 mm. Products of this kind feature a relatively high tamped density of 250 to 450 g/l.
EP2910724A1 discloses a frame filled with thermally insulating material, comprising a mixture of hydrophobized fumed silica with a mean diameter of 1 to 100 μm and an opacifier having particle sizes of 0.1 to 25 μm, with a bulk density of 100-200 g/l. This thermally insulating material is produced by mixing of the constituents, followed by densification.
EP 0725037 A1 describes granules having a median grain diameter of 10 to 120 μm based on hydrophobic fumed silicon dioxide for use as a catalyst support. Granules of this kind have a tamped density of 260 to 570 g/l and are produced by spray-drying of a silicon dioxide-containing aqueous dispersion, treatment at temperatures of 150 to 1100° C. and subsequent hydrophobization with organosilicon compounds.
European application 16181905.7 discloses the production of a thermal insulation material comprising hydrophobic silicas and opacifiers, by treatment of a precipitated pulverulent silica with a silane, mixing with a hydrophilic fumed silica, and subsequent thermal treatment at 40-200° C. The pulverulent mixture thus obtained can optionally be densified prior to thermal treatment to give a granular material having a tamped density of 100-400 g/l.
DE 2903487 A1 discloses a process for producing pulverulent hydrophobic silicon dioxides by the treatment of hydrophilic silicas with organosilicon compounds in the presence of ammonia.
U.S. Pat. No. 6,099,749 discloses a process for producing finely divided compacted compositions comprising hydrophilic silicas which have been treated with ammonia prior to the compacting.
Although the silicon dioxide-based pulverulent and granular thermal insulation materials known to date do give adequate thermal insulation, they have relatively high density and/or are not optimized in terms of mechanical stability.

Granular thermal insulation material and method for producing the same


Novel rotary valve assemblies and valve components for use with an internal combustion engine are disclosed. Valve seal assembly anchors are also described. Selected valve port geometries and axial adjustment for variable valve area for desired engine efficiency and performance are described. Novel seal assemblies and arrangements for sealing and heat transfer are also described.

In an internal combustion engine of the piston and cylinder type, nearly all designs in use in automotives today utilize "poppet" valves which intermittently open to allow intake of air and exhaust of waste gases, and close to permit the cylinders to carry out the compression and combustion cycles of the engine. A conventional poppet valve typically is spring loaded and works in conjunction with rocker arms, lifters and a camshaft the timing of which is linked ultimately to the engine crankshaft. Ideally the cycles of valve opening and closure taking place within this high pressure and high temperature environment are unimpeded by friction or parts failure, and closure is sufficiently secure to maximize compression, fuel burning and engine performance.
However, the operation of a conventional poppet valve depends upon the interaction of numerous small parts, is subjected to excessive wear, and suffers various inefficiencies. These inefficiencies include, for example, parasitic loss in the form of friction and reciprocating inertia, and pre-ignition due to high exhaust valve temperatures. These various inefficiencies often result in excessive emissions, excessive fuel consumption, and vibration and noise including, for example "engine knocking". In addition, the performance of each poppet valve and associated components also depend upon a significant volume of oil and the accompanying need for frequent oil change.
A significant source of parasitic loss in a poppet valve system is the inertial loss from reciprocating components. Moreover, as there are two or more poppet valves in use per cylinder, there are many valves total in operation for each automotive engine. The valve bodies, lifters, pushrods, and springs in operation for each valve all have a mass that is twice accelerated and decelerated every other crankshaft revolution. These loads are continually taking power from the engine, and increase exponentially with increase in engine speed.
Rotary valves offer several advantages over poppet valves. For example, at constant engine speed, a rotating cylindrical valve assembly bears no inertial load on an engine. Inertial loads with a rotary valve are born by the engine only during acceleration and deceleration and are typically extremely low. In addition, rotary valves improve the coefficient of gas flow as compared to similar sized poppet orifices and allow much larger peak valve areas than poppet valves, thereby improving high speed operation. The use of rotary valves such as those disclosed herein requires only one port in the roof of the combustion chamber to serve as both the intake and exhaust valve, thereby allowing the entire valve area to be dedicated to both intake and exhaust as required. Further, this port is unobstructed unlike with a poppet valve, the body of which obstructs a port to reduce flow in both intake and exhaust. Air flow is thereby significantly higher with the invention disclosed herein, enabling higher volumetric efficiency at high engine RPMs. Increased flow at higher RPMs increases an engine's peak power potential and therefore can enable the use of smaller more fuel efficient engines where a larger engine would otherwise be required. Engine speed moreover is not limited by a rotary valve as they are by a poppet valve. And finally, rotary valves have a much larger thermal mass and heat transfer area than a poppet valve or valves, thereby significantly reducing in-cylinder peak component temperatures to greatly lower the likelihood of pre-ignition (knocking). A lower valve temperature also allows greater compression ratios to significantly improve engine thermal efficiency.
With a world oil market price surpassing seventy dollars a barrel and predictions of ever increasing global demand and price, the high cost of dependence upon foreign sources of oil, and dire warnings from climatologists about the impending irreversible global change resulting from greenhouse gases, there is a need for innovation of the internal combustion engine to reduce its consumption of oil and its emissions, and to improve its overall efficiency. Increased fuel efficiency and reduced oil consumption and emissions and smoother operation are among the potential advantages of a rotary valve.
Numerous rotary valve designs have been proposed to replace the more conventional poppet valve. However, various drawbacks of previous designs have rendered such designs thus far incapable of achieving these objectives. For example, the continued need for lubricating oil for operation of the rotating valve assembly, and the consequential increased emissions from the burning of oil as the oiled valve assembly surface rotates into the combustion chamber are characteristic drawbacks. Achieving adequate combustion chamber sealing is a continuing challenge of a successful rotary valve system, especially under the substantial pressures and thermal stresses of an internal combustion engine and the rotational forces of a rotary valve. These challenges have led to a need in the art for a rotary valve assembly that does not suffer these drawbacks. Further, there is a need in the art for a valve designed to vary the valve parameters of timing, duration, and valve area, based upon the instantaneous demands on the engine.