Abstract: A heat driven solid adsorbent bed heat pump system and method of operating same in which the refrigerant is used both to heat and cool the beds and to heat or cool the space to be conditioned.

Abstract: An evaporator of the plate-fin construction has attached a formed housing which together with the evaporator end plate comprises a suction accumulator. A liquid conduit passes through the accumulator and induces fluid from the accumulator into the evaporator via a venturi located in the conduit. A tube inserted into one tank of the evaporator is in direct connection to the accumulator and increases storage capacity of the accumulator. A field removable filter-drier assembly is installed in the exit tank or compartment of the evaporator. A baffle is located in the accumulator section and separates liquid from gas and allows mostly gas with entrained oil to flow to the compressor. A secondary flow path which opens under low charge conditions aids in oil return to the compressor.

Abstract: Jewelry apparatus consists of a body portion having an ornamental outer surface and an ornament portion having an ornamental outer surface. The body portion includes an engagement formation preferably consisting of a cylindrical recess and a bore which extends axially inwardly from the center of the cylindrical recess. The ornament portion includes a complimentary engagement formation preferably consisting of a cylindrical neck which is slidably received in the recess of the body portion, and a post which is slidably received in the bore. When the engagement surfaces of the body and ornament portions are received in engagement, the ornamental surfaces thereof cooperatively merge so that the body portion and the ornament portion appear as an integral unit. The post frictionally secures the ornament portion to the body portion when received into the bore.

Abstract: A method for increasing stitches at intermediate positions in a row of stitches of a rib knit fabric comprising the steps of: leaving a set of two target knitting needles on the front and rear beds, respectively, unoccupied, where increased stitches are to be formed, by shifting a predetermined number of loops from the knitting needles including the target needles in either leftward or rightward direction; forming stitches on knitting needles from one end of a knitting area to before the two target knitting needles; hooking a thread of yarn on first one of the unoccupied target knitting needles located next to the knitting needle to which the thread has been supplied at the end of the preceding course; hooking the thread on the other unoccupied target knitting needles; and, moving a carriage in a reverse direction and applying the thread again to the first target knitting needle to form an increased stitch.

Abstract: A low frequency vibration type washing machine having at least one horizontally reciprocating disk is disclosed. The disk is provided on the side wall of the washing tub and horizontally vibrates in a direction perpendicular to the direction of gravity of the multi-phase washing medium, thus to generate the resonance phenomena in the washing medium inside the washing tub while saving disk drive energy. The multi-phase washing medium is made of water, detergent and air. The washing machine also includes an actuator which is coupled to the disk for driving this disk. In an embodiment, two disks are provided on the side wall of the washing tub in such a manner that they face each other. In this case, the disks may vibrate so as to form vibrational waves of the same phase or of different phases. The vibrational waves of the disks may have a phase difference larger than -.pi./2 and less than .pi./2.

Abstract: A shackle lock comprises a body, a first shackle, a second shackle, and two holding bodies. The first shackle is engageable at both ends thereof with two insertion holes of the body while the second shackle is engageable at both ends thereof with the two holding bodies, which are provided respectively with an axial hole in which the body is held. The two holding bodies are further provided with two oblong through holes corresponding in location to the insertion hole of the body. The two oblong through holes of the holding body are opposite in location to each other. One of the two oblong through holes of each of the two holding bodies is engageable with the first shackle.

Abstract: A simplified latch for luggage, cases and the like has a tubular bolt with an eccentric cam engaging beneath an over-hanging tab of a base to which the lever plate is connected by a linkage when that tubular cam is rotated by insertion of a key in a key shaft within the tubular bolt and fixed axially with respect to the lever plate.

Abstract: An apparatus for alternately retaining a selected one of a pair of keys and releasing the other one of the pair of keys is provided. The retained key cannot be released until the other key is again disposed in a retained position. The apparatus includes a base plate having a pair of key receptacles, a slider assembly slidably mounted on the base plate, a visitor key having a pinion gear and a home key. The slider assembly includes a pair of key retaining slots for respectively retaining each key and a rack for driving engagement by the visitor key pinion gear for effecting sliding movement of the slider assembly in response to rotation of the visitor key pinion gear. A conventional key can be secured to the home key to control use of the conventional key through the selected release and retention of the visitor key and the home key.

Abstract: In cumulative wire-drawing machines comprising a plurality of dies for successively reducing a diameter of a wire and blocks downstream of each one of the dies for pulling the wire through the dies, the speed of the motor driving the blocks can be automatically controlled by a wire accumulation detection device that detects changes in the amount of wire accumulated on the double-block. Specifically in the context of a double-block type machine, the blocks each comprise a lower segment being driven by the motor to pull the wire through the die, an upper segment for providing the wire to a downstream double-block through a downstream die, and a sheave carried on a ring for transferring the wire from the lower segment to the upper segment. The wire accumulation detection device in this case comprises a cam on the ring and a proximity detection device mounted to the housing of the wire-drawing machine that detects the rotation of the ring by detecting a distance to a surface of the cam.

Abstract: In a method and apparatus for shaping hollow-section workpieces such as tubes of metal, the workpiece is introduced into a pressing mold whose internal contour corresponds to the workpiece shape to be produced. After closure of the pressing mold a pressure medium in the form of solid matter particles or elements such as steel balls is pressed by means of a bar into the workpiece, applying it against the internal contour of the pressure mold. In that operation an upsetting movement of the workpiece is superimposed on the bar movement. The bar can be pressed into the workpiece in two or more steps, in which case the pressure medium is further advanced by means of a pressure cylinder between the respective steps after a respective withdrawal movement of the bar.

Abstract: A sheet bending brake comprises a first longitudinally extending member having a clamping surface and a second member for bending a workpiece clamped on said clamping surface extending longitudinally with respect to said first member. Each of the first and second members has substantially the entire length of the longitudinal edges thereof formed with longitudinally spaced intermeshing integral projections. The projections on the second member have a plurality of aligned openings. A hinge pin extends through the openings of the second member. The second member includes an integral upper tubular portion and integral upper portion comprising an outer wall that extends upwardly and outwardly from a vertical wall of the lower portion; an integral horizontal upper wall; an integral rear wall that extends downwardly and inwardly to the front edge of the upper flange.

Abstract: An improved tank bottom configuration formed from a flat metal plate of square or rectangular shape is disclosed. The plate is sheared to provide two adjacent sides which are tapered along their lengths and a notch is cut in each corner portion. By the use of stop and die members, the plate member is deformed to provide a bottom wall portion which slopes downwardly toward one corner and upwardly extending side wall portions which extend around the periphery of the bottom wall portion. A drain opening and a crease are formed in the bottom wall portion, with the crease being aligned with and spaced from the drain opening.

Abstract: A pair of forming elements incorporate features which restrain a thin foil workpiece without requiring high or excessive clamping pressures. A retaining step is provided in the second forming element having the forming cavity. It has been found that thin foil workpieces bent over and engaged by contact with the retaining step are secured against slippage with reduced clamping pressures. Moreover, the thin foil workpieces exhibit material draw during forming without the excessive lateral pressure between clamping surfaces that causes wrinkles. Substantially wrinkle-free flanges remain in the formed article.

Abstract: A scanning circuit for an array of pressure responsive sensor points which permits the sensitivity of the circuit to be controlled. In particular, the sensitivity of the circuit may be controlled by controlling a test and/or reference voltage used with the circuit and different sensitivity or resolutions may be provided for different areas of the array. The circuit also provides enhanced interelectrode isolation, permitting a single test voltage to be utilized to scan all sensor points on a given input electrode and further reduces the time required to scan the array by reducing trace capacitance discharge time and by inhibiting processing for sensor points which are not of interest. The accuracy of pressures being sensed is also enhanced by adjusting the test voltage to compensate for load variations.

Abstract: A sensor assembly for sensing gaseous or fluid medium such as sensing oxygen within exhaust gas of an automobile. The assembly provides a sensor element within a housing mounted within a S-shaped flow channel between a medium entry aperture and exit aperture. A shield is provided upstream of the sensor in a flow direction of the medium. The arrangements provide for a laminar flow across the sensor element causing reduced deposits on the surface of the sensing element for a more accurate sensor and a longer service life of the sensor element.

Abstract: An apparatus and method for determining the minimum miscibility pressure of a system comprising a gas and a liquid. A liquid-filled tube is equilibrated at a predetermined temperature and initial pressure, and pressure changes are determined as a single gas bubble is launched, rises through the tube, and stabilizes in the liquid. The measurements are repeated with fresh liquid at a series of different predetermined pressures. The minimum miscibility pressure is obtained either by finding the final pressure at which the time between launch and stabilization is constant or by evaluating the derivative of an empirically derived relationship between initial pressure and final pressure.

Abstract: A method for recognizing stretches of rough or bad road includes recognizing tank pressure values at successive evaluation instants. A change in tank pressure is ascertained from successive tank pressure values. A stretch of rough or bad road is recognized if the change exceeds a limit value.

Abstract: A device for recording the fuel usage of a vehicle capable of operating on multiple fuel types. The invention is a digital device which tracks time and/or distance parameters for each fuel type burned and stores these parameters in memory. In one embodiment, the device detects when the vehicle engine is running and what type of fuel is being burned. An electronic system clock provides the timing reference for measuring the length of time each fuel type is burned. The memory is periodically updated with the timing information. A second embodiment tracks traveling distance in a similar manner. The user may display the contents of any parameter recorded by the device on a numeric display.

Abstract: Misfiring in an engine cylinder can be detected based on the pressure therein as sensed by a pressure sensor with a high degree of reliability at any time even if the output signal of the pressure sensor contains an offset component superposed on a pressure component representative of the actual cylinder pressure. In one form, the pressure sensor output is differentiated to eliminate the influence of the offset component and then processed to generate a power stroke pressure information signal in the form of the time of a pressure-change peak in the differentiated pressure sensor output or an integrated value of the differentiated output, which is then compared with a threshold so as to determine whether misfiring took place in the cylinder.

Abstract: Friction torque of a motor undergoing testing is measured by supporting an electrical motor on a test fixture and connecting a torque measuring device to its output shaft. The motor shaft is rotated in the reverse direction and while the motor shaft is freely rotating, power is applied to the motor and two torque measurements are taken to determine friction torque. The first is while the motor is still rotating in the reverse direction, and the second is taken from zero rpm to approximately 50 rpm. In both cases, the torque is measured while the motor shaft is near zero rpm, thus representing locked rotor torque. Half the difference between these two torque measurements will yield the value for friction torque. Motor torque is continued to be measured while the motor is accelerated to its maximum speed, and the value of this measured torque can then be adjusted by the value of the friction torque to provide a measurement of the actual torque of the motor being tested.

Abstract: The process and device are for detecting combustion irregularities in an internal combustion engine. The process consists in measuring the time intervals between the angular positions of the crankshaft, in grouping these time differences in sets of samples corresponding to each combustion phase, in calculating from each set a critical parameter that is representative of the variation in the instantaneous speed at the moment of combustion, and in comparing this parameter with a fault threshold in order to make a combustion diagnosis. Diagnosis at medium and high speeds is thus possible.

Abstract: A tire pressure management system including a tire condition monitor connected to the tire so as to be interactive with air pressure in the tire and for selectively measuring a pressure in the tire, a controller, and a display. The tire condition monitor includes a transmitter and a receiver. The controller also has a transmitter and a receiver connected thereto. The transmitter of the controller serves to transmit a first radio signal to the receiver of the tire condition monitor. The receiver of the controller serves to receive a second radio signal from the transmitter of the tire condition monitor. The display is connected to the controller so as to display a humanly perceivable indication of a condition of the tire. An air compressor is mounted to a wheel of the tire so as to deliver air to an interior of the tire when the pressure of the tire is below a predetermined value.

Abstract: A free piston shot tube tunnel having a high speed valve for releasing the piston to start the piston shot. A further feature of the present invention is a free piston shock tube/tunnel having a high speed valve for releasing pressure from the compression tube into the shock tube.

Abstract: A rainfall rate gauge contains a turbine which turns on a horizontal axis and floats in a chamber about half full of water. Turbine motion is measured and electronically recorded by an optical sensor. The blades of the turbine have a reverse rake so that the a portion of the water captured in each bucket is carried above the water surface before being released when the blade tip breaks the water surface. This arrangement prevents unrestrained free wheeling of the turbine, and results in more precise measurement, particularly at very low rainfall rates.

Abstract: The invention provides a workpiece balancing and correction apparatus having separate modular stations. A measurement station provides balance measurement and correction auditing functions. A correction station provides material weight correction in one or two planes. A transfer module is designed to transport workpieces between the measurement module and the correction module and maintain the cycle speed of operation of the overall machine in keeping with constant activity at the slowest module.

Abstract: A, micromechanical tuning fork gyroscope is fabricated from a unitary silicon substrate utilizing etch stop diffusions and selective anisotropic etching. A silicon structure is suspended over the selectively etched pit. The silicon structure includes at least first and second vibratable structures. Each vibratable structure is energizable to vibrate laterally along an axis normal to the rotation sensitive axis. The lateral vibration of the first and second vibratable structures effects simultaneous vertical movement of at least a portion of the silicon structure upon the occurrence of angular rotation of the gyroscope about the rotation sensitive axis. The vertical movement of the silicon structure is sensed, and a voltage proportional to the movement is generated, for providing an indication of angular rate of rotation detected by the gyroscope.

Abstract: The vibrator includes, for example, a triangular prism shaped vibrating body. On each of three side faces of the vibrating body, piezoelectric elements are formed respectively. The vibrating body makes bending vibration by giving a driving signal to one or two piezoelectric elements. The vibrator is used in a vibratory gyroscope. In this case, for example, one piezoelectric element is used for vibrating the vibrator. When a rotating force is applied to the vibratory gyroscope, a Coriolis force is exerted to produce output voltages on the remaining two piezoelectric elements corresponding to the rotational angular velocity.

Abstract: A method of measuring a length of a conduit comprises the steps of: supplying air into a conduit to insert a filamentary body into the conduit by flow of the air; detecting arrival of a forward end of the filamentary body at an outlet of the conduit; and measuring the length of the conduit from the length of the filamentary body inserted into the conduit. An apparatus for measuring a length of a conduit, comprises an air supply device for supplying air into the conduit; a filamentary body including a wire and a plurality of elastic large-diameter members attached to the wire; and a device for detecting that a forward end of the filamentary body arrives at an outlet end of the conduit, where the length of the conduit is measured from the length of the filamentary body inserted into the conduit.

Abstract: A method for detecting combustion misfires in internal combustion engines includes calculating a non-concentricity value from fluctuations in angular speed of a crankshaft, and dropping the non-concentricity value below a negative non-concentricity limit value if a combustion misfire is present. If the non-concentricity value drops below the non-concentricity limit value, a value for a stretch of bad road is calculated from successively calculated non-concentricity values, and the value for a stretch of bad road is dropped below or made of equal magnitude to a positive limit value for a stretch of bad road, if a stretch of bad road is present. The previously indicated combustion misfire is not confirmed if the value for a stretch of bad road drops below or is of equal magnitude to the limit value for a stretch of bad road. However, the previously indicated combustion misfire is confirmed if the value for a stretch of bad road exceeds the limit value for a stretch of bad road.

Abstract: A series of devices for in vivo imaging of cellular architecture in a variety of tissues. A 200 MHz transducer is mounted on the tip of a cardiac catheter, gastroscope, colonoscope, bronchoscope, laparoscope or similar device, where it is moved mechanically to produce B-mode images of cells in the tissue. The ultrasound beam is focused in a subsurface region of tissue, and ultrasound which is backscattered from the focal zone is analyzed to produce images. Because heart motion may interfere with cardiac imaging, images are gated in mid-diastole for cardiac applications.

Abstract: A scanner head for ultrasonic imaging of structures generates a display through an ultrasonic transceiver. The scanner head includes a transducer adapted to engage the surface of the structure. Rollers are positioned fore and aft the transducer, and one roller drives a position increment signal generator which drives the transceiver and display circuitry. A couplant delivery system includes nozzles bracketing the transducer in the direction of movement of the scanner head. The flow is controlled by a single valve on top of the head. In this manner, couplant in the desired amount is delivered correctly and concurrently as scanning proceeds.

Abstract: Apparatus for non-destructively inspecting for faults in or beneath the surface of structures, such as debonds or delaminations in composite materials, or cracks, broken stringers, delaminations and the like in semi-monocoque structures, includes at least one spark gap discharge device displaced from the test object which focuses an acoustic pulse onto a small local area of the object for vibrationally exciting the surface of that area. A laser Doppler camera system, also displaced from the test object directs a laser beam onto the excited area and derives from light energy reflected back from the excited area the velocity of out-of-surface displacement of, and relaxation frequencies generated by, the surface of the excited area and provides an indication of whether a fault is present in that area.

Abstract: An apparatus for testing the strength and performance of various building structures, such as doors, windows, storm shutters and panels, under hurricane type conditions, the apparatus including a vertically supported wall and a movable test structure mounting and support assembly including a frame for supporting a building structure to be tested. The frame is movably attachable in sealed engagement to a front face of the wall, such that the test structure is disposed in close, spaced relation to the wall, creating an air tight cavity between the building structure and the front face, wherein airflow is selectively delivered to or removed from the cavity by a diverter valve along an airflow conduit connecting between an air passage hole in the wall and to a high volume, low pressure blower. A computer controls the diverter valve and monitors pressure in the cavity to selectively control and rapidly change the cavity pressure through a range of predetermined positive and negative pressure levels.

Abstract: A fluid condition sensing transducer includes a fluid containment device having a cylindrical side wall including an inner surface in contact with a fluid and an outer surface, a diaphragm integral with the side wall defined by a recessed portion of the side wall and extending between the inner surface and a recessed portion of the outer surface, and an in-situ, non-invasive sensor mounted on the recessed portion of the outer surface for sensing surface conditions of the diaphragm whereby the condition of the fluid in the containment device is sensed.

Abstract: An electrical type strain gauge for measuring both micro and macro deformations. The gauge may be constructed from thin films of homogeneously conductive polymers, including soluble polyaniline-based conducting polymers and ion-implanted organic polymers. The gauges are characterized by unexpected piezoresistivity from materials having high bulk resistivity, thermal stability, good flexibility, photoimageability and without adding carbon or metal particulate material to the polymer.

Abstract: A test block and method of testing for law enforcement personnel to quickly and easily test the strength of and gauge the dimensions of a handcuff key before it is used in actual handcuffs. The block has an opening in its center which receives the latch tab end of the key and also serves as a gauge for the maximum permissible dimensions of a handcuff key. To test the key, the officer inserts the latch tab end in the opening and exerts pressure on the key with his thumb while holding the block in a stable position. The test block has a thickness which is sufficient to hold the key in the test block as it is being tested.

Abstract: A rising step-load test apparatus for subjecting the notched region of a fracture specimen to tension by applying four-point bending to the specimen, and having an adaptor that can fit into the test apparatus in four-point bending and convert the bending load to an axial tensile load on a second specimen for which the adaptor serves as a fixture. The test apparatus applies four-point bending to either the fracture specimen or the adaptor through two oppositely situated simple supports at one end of the fracture specimen or adaptor and two other oppositely situated simple supports at the other end of the fracture specimen or adaptor. The adaptor employs two pivotally attached linking members attached to the two ends of the second specimen to transfer a pure axial tension to the second specimen for testing in axial-tension mode. A chemical bath is provided for an accelerated test of hydrogen embrittlement.

Abstract: A spin riffle sampling apparatus distributes a sample source quantity of particulate material in a predetermined number of increments, 60 for example, to each of a smaller number, 4 for example, of radially disposed bins on a rotating platform. The bins include top openings which pass through a falling zone of material to receive material into the bins. The width dimension of each opening decreases with increasing radial displacement from the axis of rotation of the platform. The bins also may be forwardly pitched relative to the direction of rotation of the platform so as to induce a down draft to control dusting.

Abstract: A pipette, comprising: a cylinder (1) with liquid passage (3), a plunger (4), and a plunger operating assembly (5) for moving the plunger in the cylinder; the operating assembly comprising a body (6), a threaded rod (7), an operating member (8) cooperating by mediation of threads with the threaded rod, and a power unit (9) for rotating the threaded rod and the operating member relative to each other for moving the plunger by mediation of the threaded rod and the operating member when the threaded rod and the operating member are rotated relative to each other with the aid of the power unit; the thread of the threaded rod (7) or alternatively that of the operating member (8) being non-linear locally over a certain transition range.

Abstract: Disclosed is a tool-like cartridge for preserving a soil sample which may be contaminated with a volatile organic compound (VOC). The cartridge includes a barrel and a plug in the barrel for sealing the barrel proximal end during and after sampling and for later expelling the soil sample from such barrel. A threaded portion is on the barrel for attaching a handle and such portion has an opening through it. From the moment of sample extraction until later sample expulsion for analysis, the plug and its resilient seal member substantially prevent vaporized VOC from escaping from the cartridge. A new method for obtaining a soil sample for analysis is also disclosed.

Abstract: An apparatus for inspecting automatic lock sliders comprises a table for horizontally holding and intermittently moving sliders, an elevating board disposed above the table and adapted to be reciprocated vertically at a predetermined stroke while the table is at a stop, an auxiliary support block attached slidably to the elevating board so as to be vertically reciprocated above the slider held on the table, and a retainer rod and a pressure rod both attached to the auxiliary support block as allowed to reciprocate vertically and elastically urged downwardly.

Abstract: In one aspect of the present invention, a method for controlling an interrupted shift for a powershift transmission is disclosed. The method first determines which clutches are active and then classifies each of the active clutches. Thereafter, the method calculates the timing associated with the engagement and disengagement of the classified active clutches to result in a smooth transition to the final selected gear.

Abstract: The present invention relates to an improved gearbox having both a symmetrical housing and straddle-mounted bearings, to provide a gearbox which is both versatile and moderate in cost.

Abstract: A gear mounting for use in a compound change gear transmission (10) having an intermediate wall portion (50), and a shaft support portion (66) axially spaced from the intermediate wall portion (50). Disposed axially between the intermediate wall portion and the shaft support portion is a gear member (48). The intermediate wall portion and shaft support portions define aligned shaft bores (92,96) with the shaft member (98) disposed therein, and including retention means (122) to retain the shaft member within the bores. The shaft member defines lubricant passage means (100) permitting flow of lubrication fluid through the shaft and into a set of bearings (64) which receive the forward end of an adjacent countershaft (60). The outer surface of the shaft member (98) defines an inner race for a set of bearings (120) disposed between the shaft and the gear member (48). The disclosed mounting arrangement substantially simplifies and strengthens the mounting of the gear member (48).

Abstract: A manual transmission shifter, which comprises a ball mounting a shift lever, a lateral shift control arm, and a depending shift control member, is mounted in a plastic shifter housing having a plastic closure plate. The housing has a plurality of spaced integral resilient spring fingers contoured to form a socket for receiving the ball. The fingers are interconnected at their upper ends to define an upper opening for the shift lever. The spring fingers define an opening smaller than the ball diameter at their bottom free ends and flex to receive the ball and contract to snugly embrace the ball. The shift control arm projects through a side slot in the housing to enable up-and-down vertical movement of the control arm from a centered neutral position. An integral spring finger biases the control arm to the neutral position. The closure plate has an annular surface which embraces the bottom ends of the spring fingers to define the size of the socket.

Abstract: A drive apparatus, along with an XY drive apparatus on which it is equipped, is provided which, together with allowing highly accurate driving and positioning of a driven object by absorbing deflection in the radial direction of a nut, achieves reduced size of the apparatus and simplification of its structure.

Abstract: A connector for engaging brake cables of a bicycle, the connector is composed of a first part and a second part, the first part has a first hole, a second hole and a bore defined therein, two passages defined in the first part and each of which located above the first hole and the second hole respectively, a tubular portion extending from the first part and defining a counter-bore therein in communication with the bore, the second part has a first recess, a second recess and a third hole defined therein, two protrusions extending therefrom and a groove defined therein between the first recess and the second recess and communicating with the third hole, the first part and the second part engaged together by extending the two protrusions through the two passages and a first cable and a second cable respectively received in the first recess, the first hole and the second recess, the second hole, a bolt having a hole defined therein for a third brake cable extending therethrough and the bolt threadedly engaged to

Abstract: An adjustable tie-rod assembly for an automotive vehicle has inner and outer rod end sections, and an intermediate rod section. The intermediate and inner rod end sections are rotatably connected together. The intermediate rod section is threaded on the outer rod end section and a jam nut maintains this connection. A stud projects laterally outwardly from the outer rod end section for connection to a steering arm.

Abstract: A sharpener has two sharpening members pivotally mounted on opposite sides of a reference plane. Each sharpening member includes a counterweight portion below its pivot and a sharpening portion above its pivot. The sharpening portions have convex sharpening edges which overlap laterally to form a vertically movable V-shaped slot for receiving a cutting blade. A cutting blade is placed in the slot and moved lengthwise and downwardly. The downward movement causes the vertex of the V-shaped slot to move down, but the slot's vertex angle remains substantially constant because the curvatures of the sharpening edges increase progressively from upper regions to lower regions of the sharpening edges. The centers of gravity of the sharpening members are laterally inboard of the pivots, and the sharpening edges are higher than the pivots. The sharpening forces exerted by the sharpening edges against a cutting blade increase in response to downward movement of the slot vertex.

Abstract: In an automated machine for cutting cloth or fabric and similar sheet materials the knife is made from a high-alloy tool steel to provide the knife with a sharp cutting edge capable under a given set of conditions to cut sheet material for a far longer period of time before requiring re-sharpening than the case with the knives previously used in such machines. A sharpener is also provided which allows the knife after becoming dull to be returned to a sharp condition while removing only a minimum amount of the knife material, thereby further increasing the service life of the knife.