Showing papers on "Pulley published in 1991"

Passive mechanical gravity compensation for robot manipulators

Abstract: A simple mechanical method for passively compensating for gravitationally induced joint torques is presented. This energy-conservative gravity-compensation method is suitable for a variety of manipulator designs. With cables and appropriate pulley profiles, changes in potential energy associated with link motion through a gravity field can be mapped to changes in strain energy storage in spring elements. The resulting system requires significant energy input only for acceleration and deceleration or to resist external forces. A testbed with both single- and double-link configurations has demonstrated the efficiency and accuracy of this gravity compensation method, as well as its robustness under dynamic loading conditions. >

Coupled tendon-driven multijoint manipulator

Abstract: A coupled tendon-driven manipulator called the CT arm is introduced, an its control is discussed. The CT arm has a specific tendon traction force transmission mechanism in which a pair of tendons for driving a joint are pulled from base actuators via pulleys mounted on the base-side joints. The mechanism makes the most of the coupled drive function of the tendon traction forces and thus can exhibit enormous payload capability. The CT arm is solidly structured and can be inexpensively manufactured because of its mechanical simplicity. A control algorithm which minimizes the square sum of the traction force of tendons while satisfying given restrictions is introduced. The validity of the control method is shown by computer simulation. >

Electronically controlled continuously variable transmission

Abstract: An electronically controlled continuously variable transmission system is provided with a driving belt trained over a primary and secondary pulley. The primary pulley is provided on a primary shaft and the secondary pulley is provided on a secondary shaft. Each pulley has corresponding spaced, conical pulley halves and at least one of the corresponding pulley halves is axially movable by respective primary and secondary moving devices. The transmission further includes a primary electronic control system for controlling the transmission ratio and a secondary electronic control system for controlling the belt tension. The primary electronic control system permits the operator to select from fuel economy, sporting, and maximum comfort performance modes. The primary electronic control means controls the transmission ratio in accordance with the performance mode selected. The moving devices include standby operating valves to permit continued operation of the transmission in case of power failure.

Constant tension exercise device

Abstract: An exercise device has a support frame and a lever arm attached to the support frame and pivotably movable between a rest position, wherein the lever arm hangs downwardly relative to the support frame, and an extended position, wherein the lever arm is pivoted upwardly from its rest position A range of motion (ROM) block is rigidly attached to the lever arm, and pivots with the lever arm The orientation of the ROM block relative to the lever arm can be selectively varied A tackle is attached to the ROM block to provide an opposing force to motion of the lever arm from the rest position to the extended position This tackle includes two pulleys that are attached to the ROM block The tackle also includes a substantially taut cable that extends between the pulleys, and the cable is connected to a mass The position of the pulleys relative to the lever arm is established such that the magnitude of the force required to move the lever arm toward the extended position is approximately equal to the magnitude of the weight of the mass

Camshaft advancer for improving efficiency of combustion engine - uses slip-ring-free electric motor to alter position of camshaft relative to camshaft gear using planetary gearbox

Abstract: The camshaft (3) is driven (e.g. by belt or pulley) from a crankshaft through gear wheel (5) coupled to an extension (2). This acts as the ring gear of a planetary-type gearbox with an intermediary gear attached to the camshaft by bolt (20). An eccentric planet gear carrier (17) is fixed to the rotor (21) of an electric motor whose stator (22) is fixed in the housing (34). Excitation of the motor will cause relative movement between the camshaft gear (5) and the camshaft (3). ADVANTAGE - Exact positioning, no slip rings, min. friction loss. Minimises fuel consumption.

Biomechanics of pulley reconstruction

Abstract: The biomechanics of the reconstructed flexor retinacular pulley system are poorly defined. We used a mathematical theoretical model, confirmed by a cadaver model, and a clinical radiographic model to evaluate a variety of different joint and pulley combinations. We examined twenty-four sets of radiographs of 12 fingers in 9 patients for whom excursion was measured and predicted by the mathematical model. The 30 pulley combinations evaluated in the in vitro cadaver model showed statistical correlation with the biomechanical mathematical model. Recommendations of clinical application on the basis of this information include the following: (1) Two pulleys should be placed, one proximal and one distal to each joint. (2) These two pulleys should be balanced about the joint axis both in distance from the axis and in pulley height. (3) They should be positioned at the edge of the flare of the metaphysis. (4) The three individual joints can be balanced, one to another, by maintaining minimal bowstringing at all three joints. In this way, the relative excursion at the joint and torque at the joint will be maintained in a physiological ratio as close to normal as possible.

Drive device of slide door

Abstract: A door drive device is disclosed, which comprises a guide rail (2) for defining in the body (1) of the vehicle a way along which the slide door (3) moves; first and second pulleys (17, 20) arranged at spaced positions of the vehicle body (1); an electric drive unit (8) for driving the first pulley (17); an endless belt (22) put around the first and second pulleys (17, 20) with a slack thereof; a bracket (23) for connecting a portion of the endless belt (22) to the door (3); and a tensioning device for tensioning the endless belt (22). Due to provision of the slack of the belt (22), various advantages are obtained particularly when the door drive device (8) of the invention is used in combination with other door controllers.

Apparatus for mounting equipment to wheelchairs

Abstract: An apparatus (10) for movably mounting equipment (11) on a wheelchair (12) having an armrest (12a) and a back support (12b), which comprises first and second pivot assemblies (20, 21), a longitudinal body member (40) spacing and joining the first and second pivot assemblies (20, 21) and rotatable about a fixed axle (50) of the first pivot assembly (20). There may also be provided a device (22) to attach the fixed axle (50) to the wheelchair (12), a rotatable axle (51) in the second pivot assembly (21) supporting the equipment (11), and an assembly such as pulleys (80, 81) and a cable (83) for rotating the rotatable axle (51) as a function of the rotation of the body member (40) relative to the fixed axle (50). Rotation of the body member (40) relative to the fixed axle (50) effects rotation of the rotatable axle (51) such that the equipment (11) remains orthogonal to the armrest (12a) of the wheelchair (12) during movement from a position in front of the wheelchair (12) to a position to the rear of the back support (12b) of the wheelchair (12).

Simulated stair climbing exercise apparatus having variable sensory feedback

Abstract: A simulated stair climbing exercise apparatus having variable sensory feedback is provided. Sensory feedback, in the form of a lifting force acting on a lifting foot of the operator, varies with the operator's location in the stepping stroke. Maximum sensory feedback is provided at a lower portion of the stroke, minimum sensory feedback is provided at an upper portion of the stroke and maximum feedback at the lower portions. Sensory feedback is effected by means of direct interconnection of left and right foot mechanisms in combination with a spring. Direct interconnection is achieved by a cable routed around a series of pulleys such that a downward force on one foot mechanism results in an equal and opposite lifting force on the other foot mechanism. One of the pulleys is a floating pulley that is free to move and its positioned based upon the operating position of the stepping stroke. The spring is connected to the floating pulley such at 1) the direct interconnection cable controls the lifting force in the lower portion of the stroke, 2) the spring controls the lifting force at the upper portion of the stroke, and 3) a combination of the cable and spring control lifting force in the mid range.

X-y drive apparatus

Abstract: An X-Y drive apparatus suitable for use in positioning an electronic component or the like at a desired position, such as a mounting position of a printed circuit board, is provided. Each of X and Y table units includes an elongated housing provided with a pair of stationary pulleys at its opposite ends and a table provided with a pair of moving pulleys. A pair of brackets is also mounted on the housing, each located between one of the stationary pulleys and a corresponding one of the moving pulleys. A belt, having its one end fixedly attached to one of the brackets, extends first around one of the moving pulleys, then around each of the stationary pulleys, and then around the remaining moving pulleys with its remaining end fixedly attached to the remaining bracket.

Chain pulling device

Abstract: A pulling device for a roll shaft for roller blinds or screens comprises a housing, a chain pulley situated in the housing and a chain slung around the pulley. The chain is formed by a cord with a number of beads distributed at regular interval along the length. The pulley is provided with a central channel and a series of notches at the periphery to receive the cord portion and the beads of the chain, respectively. The chain is readily pulled to drive the pulley and, in turn, the roller shaft, to wind up or to unwind a roller blind or screen. When the pulling force is released the pulley will be automatically braked by means of the chain itself by the gravity of the roller blind or screen.

Hydraulic control apparatus for belt-and-pulley type continuously variable transmission, incorporating means for optimizing belt tensioning pressure

Abstract: A hydraulic control apparatus for a vehicle continuously variable transmission including a pressure regulating valve having a valve spool which operates depending upon a determined current speed ratio of the transmission and a currently detected required output of the vehicle engine, to generate a controlled belt tensioning pressure for controlling the tension of a transmission belt at a required minimum level. The apparatus further includes a device responsive to an electric signal, for generating a pilot pressure to be applied to the valve, and an electronic control device for calculating a basic output pressure of the valve, based on the current speed ratio and the currently required output, according to a stored predetermined relationship among these two parameters and the basic output pressure, to determine the electric signal so that the belt tensioning pressure coincides with the optimum value.

Couch apparatus for medicine

Abstract: A couch apparatus for medical use, comprising a lower base fixed on the floor, an elevating mechanism mounted on the lower base, an upper base fixed on the elevating mechanism, a tabletop mounted slidably on the upper base, and a tabletop slide mechanism. The tabletop is provided with a belt having end portions fixed to end portions of the tabletop along the longitudinal axis of the tabletop. The belt has a slack intermediate portion. The upper base is provided with a drive pulley which engages the intermediate portion of the belt. The upper base is also provided with driving means for rotating the drive pulley and with belt guide rollers for restricting lateral motion of the belt as the drive pulley moves the belt and tabletop longitudinally.

Cam loaded continuously variable transmission

Abstract: A continuously variable transmission utilizes a cam loading device with a hydraulically controlled CVT of the metal V-belt type. The cam loading device applies an axial loading force to the pulley flanges in proportion to the output torque. A hydraulic mechanism positions the pulley flanges to compensate for the limited axial movement of the cam mechanism. A preload spring and hydraulic cushion provide a necessary preload while cushioning shock from reversal of torque. The loading force on the CVT is permitted to vary with the output torque to provide improved efficiency for a full range of automotive driving conditions.

Garage door operator with plastic drive belt

Abstract: A garage door operator (20) for moving a garage door (26) between open and closed positions includes a head unit (28) for being held by a support structure positioned remote from the door (26) with the head unit (28) having a motor (48) and a drive wheel (60) with spaced teeth on its periphery for being driven by the motor (48). The operator (20) also includes an elongate rail (40) having a first end which is held by a support structure disposed adjacent and above the door (26) with the rail (40) including a pulley (46) located adjacent the first end. The rail (40) also includes a second end for being held adjacent to and in alignment with the drive wheel (60). The operator (20) also includes a drive belt assembly (34) for training about the drive wheel (60) and the pulley (46) and for being supported by the rail (40). The belt assembly (24) includes a length of a plastic belt (76) with teeth (78) on one surface thereof matching the teeth (42) on the drive wheel (60). The belt assembly (34) further includes a trolley (36) for connection to the garage door (26) and a first connector (82) for joining one of the plastic belt (76) to one end of the trolley (36). The connector (82) includes a belt clip (96) including a pair of spaced, aligned side walls (100,102) with one side wall (100) having an inside surface with undulations (106) corresponding to the teeth (78) of the plastic belt (76). The connector (82) further includes a clip holder (98) deformable from an as-formed position in which the holder can receive the side walls flanking the belt (76) with the belt teeth (78) aligned with the undulations (106), to a deformed position in which the holder firmly holds the side walls with the belt positioned therebetween.

Belt conveyor input station

Abstract: An input station for a belt conveyor of the kind including a continuous conveyor belt that moves in a conveyor run through an input station to a discharge location, around a head pulley, and in a return run around a tail pulley back to the input station and the conveyor run. At the input station the conventional center support rollers are retained but the support rollers along the sides of the belt are replaced by a plurality of elongated, stationary, flat support members that support the sides of the conveyor belt throughout the input station, improving the seal to input station skirtboards and materially reducing or eliminating input leakage while maintaining roller support and flexibility in the center of the belt, with minimal friction increase.

Roll-up industrial door having a combined pulley for counterweight and spring tension belts

Abstract: A roll-up door for enclosing the doorway in a building The door comprises a horizontal rotatable drum mounted above the doorway and a flexible door panel is wound on the drum A pulley is secured to each end of the drum and the first ends of a pair of belts are secured to each pulley and the belts are wound in overlapping relation on pulley so that adjacent convolutions of each belt are separated by convolutions of the other belt The free end of one belt is dead-ended on the frame, and a counterbalancing weight is attached to the belt intermediate its ends and exerts a counterbalancing force to wind the door panel on the drum The free end of the second belt is connected to the lower end of the door panel and a pair of springs are connected to the second belt intermediate its ends and the springs exert a tensioning force to stretch the door panel when the door panel is in the closed position

Force ratio control of continuously variable transmissions

Abstract: A control arrangement for a continuously variable transmission utilizes a lationship between force ratio, speed ratio and the factor of safety to determine the force necessary on the secondary sheave to prevent belt slippage. The control system improves the efficiency of the transmission by reducing the excess clamping force between the CVT chain-belt and the secondary pulley sheave.

Window shade mechanism for a modular aircraft window

Abstract: Device for raising and lowering a modular aircraft window having an interpane, outerpane, frame assembly securing the inner and outer pane, collapsible shade with a fixed and movable end, the device comprising a block and tackle having a movable pulley and more than one fixed pulley, the movable pulley and fixed pulleys connected by a cable fixed at one end and attached at second end to the moving end of the collapsible shade. Moving the movable pulley effects a movement, through the cable, through the moving end of the collapsible shade, and creates a mechanical advantage multiplying the distance moved by the lever.

Pulley with integral fastener and spacer

Abstract: A one-piece metallic belt driven pulley has a hub, an annular belt engaging wall having an outer belt engaging surface and a radially extending web that connects the hub and belt engaging wall. The hub has an internal bore defined by a tubular inner surface. At least a portion of the tubular inner surface that defines the bore has a plurality of axially spaced threads to form an axially extending threaded portion. In use, the threaded portion of the bore is threaded onto an axially extending thread on an outer surface of the shaft to secure the pulley to the shaft. One end of the hub takes the form of a nut having a hexagonal outer configuration that is adapted to be engaged by a tool for screwing the pulley onto the shaft. The other end of the hub forms an axially extending integral spacer, the end of which is located outwardly of an end surface of the pulley.

Space-saving test head positioner - has hollow shaft clamping to stand with reduced counterweight via pulley system

Abstract: With an additional moment support (13) the outrigger (6) is secured against horizontal rotation. The outrigger (6) is clamped by means of a hollow shaft onto the guide stand. A vertical fine adjustment takes place via an additional lockable toothed wheel gear (22), and hand crank (23). A counter-weight arrangement takes place via a loose roller (9) so that, through the principle of a block and tackle, the counterweight is smaller. Arcuate slope adjustment of the test head holder may be achieved via an eccentric drive. The pulley block may have a double wheel for a chain. USE - Three axial adjustment of test load.

Conveyor installation and shock absorbing elements for use therein

Abstract: A conveyor installation includes an endless belt wound around head and tail pulleys which extends between an impact station wherein material is placed on the belt and a drop off zone wherein the material is removed from the belt. Shock absorbers are disposed beneath the belt at the impact station to dissipate energy imparted on the belt by the material. In one embodiment, the belt is formed of flexible, textile reinforced material and the shock absorbers are in the form of a plurality of rectangular elements having a generally planar upper surface for supporting substantially the entire undersurface of the belt in the impact station. In another embodiment, the belt is formed of rigid steel reinforced material and the shock absorbers are in the form of a plurality of closely spaced rollers. In both embodiments, downstream of the impact station are located idler rollers for supporting the belt at spaced locations. The idler rollers are mounted on a support frame via shock absorbing elements in the form of rings. Each of the shock absorbing elements is formed of elastomeric material and has at least one passage formed therein and configured so that the body wall surrounding the passage is generally K-shaped in section and functions as a buckling element.

Method and apparatus to check the acceptableness of the state of wear in the covering fabric of a driving belt

Abstract: A method and apparatus for carrying out the checking of the state of wear of a covering fabric in a driving belt (2) mounted on a plurality of pulleys (3, 4, 5) by measuring the electric resistance variations of the belt fabric. The apparatus provides that at least two of the pulleys (3, 4, 5) should be electrically insulated with respect to each other and connected to an electric circuit (20) designed to apply an electric voltage to said pulleys in order to carry out the measuring of the electric resistance of the fabric exhibited by belt stretches (A, B) comprised between the pulleys themselves. The electric resistance thus found lends itself to be compared with predetermined resistance values corresponding to different states of wear of the belt (2) fabric. The work surface of the belt (2) is coated with an electrically conductive fabric (12) acting by contact on the pulleys (3, 4, 5) and having characteristics of tensile strength.

Multiple use exercise device

Abstract: A compact multiple use exercise device removably secured in doorway, comprising a telescopically adjustable chinning bar which locks at any longitudinal increment allowing it to be adjusted to fit different doorway widths. The bar is supported at each end in the doorway by hangers which have open tops to allow the bar to be easily removed and stored when not in use. Weight resistance is provided by standard weight plates which are placed on the carrier which is coupled to a cable which runs through a first pulley attached to the chinning bar, and optionally through a second pulley, and attaches to a handle, lat bar, or leg strap depending on which exercise is desired. With the cable running through the first pulley, an upward and lateral resistance is created which may be used for exercises which simulate golf, baseball, swimming and throwing; as well as several standard weight training exercises. The second pulley may be positioned to change the direction of resistance on the cable to an upward, downward or lateral direction. Rowing exercises are also possible when the second pulley is attached to a telescoping lat bar which may be held low to the floor at each side of the door frame.

High load force transmission belt

Abstract: A force transmission belt having a plurality of block bodies each with laterally spaced pulley-engaging surfaces, an endless band to be trained about a pair of pulleys, cooperating structure on the endless band and the block bodies for maintaining the block bodies in an operative position on the endless band with the block bodies slidable lengthwise of the endless band and positioned so that the laterally spaced pulley-engaging surfaces frictionally engage a pulley about which the endless band is trained, and channel structure in at least one of the block bodies for guiding lubricant from a point between adjacent, engaged block bodies and the endless band to a location outside of the one block body to minimize wear between the adjacent block bodies during operation.

Continuously adjustable cone pulley - consists of pair of cone pulleys with control

Abstract: The continuously adjustable cone pulley looping gear has two relatively adjustable pairs of cone pulleys (1,2), and a control subjected to a pressure medium on the drive and driven side and each with a torque-sensor. A circuit for controlling the transmission is fed by a pump. The axially displaceable pulley part of the pair of pulleys on the drive and driven sides are joined to the parallel-series controls. USE/ADVANTAGE - The friction gear has a contact pressure dependent on momentum or transmission.

Spherical tooth pulley

Abstract: In an annular pulley for driving a belt having a series of spaced openings therein, the improvement comprising, a series of circumferentially-spaced annular openings in the pulley periphery, a series of spherical balls in the openings in the pulley periphery, the balls being retained in the openings only by a press fit and extending protusively outwardly from the pulley at spaced intervals therearound in defining a series of rounded teeth engageable in the spaced openings of the belt.

Portable pulley exerciser body fitness apparatus

Abstract: A portable pulley exerciser body fitness apparatus is provided and consists of an elongated bar, a pair of pulleys, each affixed to one end of the elongated bar, a cord extending about the pulleys and a pair of handles, each removably affixed to one end of the cord so that a person can grip the handles to do exercises.

Hydraulic control apparatus for power transmitting system including belt-and-pulley type continuously variable transmission and torque converter equipped with lock-up clutch

Abstract: A hydraulic control apparatus for controlling a vehicle power transmitting system including a belt-and-pulley type continuously variable transmission and a torque converter provided with a lock-up clutch. The transmission includes a pair of hydraulic actuators one of which receives a belt tensioning pressure for controlling a tension of a transmission belt. The hydraulic control apparatus includes a lock-up clutch control valve which is selectively placed in an engaging and a releasing position for engaging and releasing the lock-up clutch, respectively, a slip control valve for controlling an amount of slipping of the lock-up clutch until the clutch is fully engaged, a pressure control device for raising the belt tensioning pressure so as to increase the tension of the transmission belt; and a pilot-pressure generating device for applying a pilot pressure simultaneously to the slip control valve and the pressure control means, so that the belt tensioning pressure is raised while the slip control valve controls the amount of slipping of the lock-up clutch.

Anti-backlash drive system

Abstract: An anti-backlash rack and pinion drive system comprising a pair of spur gears on parallel shafts engaging a rack with countertorque preload imposed by a positive timing belt engaging a pair of pulleys respectively coupled to the shafts. Slack on one side and a resilient transverse load applied to the other side of the belt provides counterspur gear tooth pressure on the rack equal to the maximum drive load effected through reversible rotation of one of the shafts.