Showing papers on "Pulley published in 1987"

In vivo registration of Achilles tendon forces in man. I. Methodological development.

Abstract: Mechanical behavior of muscle and its control is largely unknown under normal movement conditions. The present report deals with the methodological development to record directly in vivo forces from the human achilles tendon (AT) when the subjects perform normal movements ranging from slow walking to maximal sprinting and jumping. The development began with animal experiments, which dealt with the transducer design, surgical operation procedures, and duration of implantation. The first human experiment utilized an E form transducer implanted around the AT under local anesthesia. The transducer was kept in situ for 7 days, and on the 8th day recordings were made on simple plantar flexion movements and during slow walking. Further development led to final selection of a "buckle"-type transducer, and the measurements can be made immediately after operation and they usually last 2-3 h. The AT transducer can be calibrated by placing the subject in a prone position on to a calibration table. His operated foot was placed in a special shoe, the axis of which coincided with that of the ankle joint. A pulley system with known weights was used to dorsiflex the foot. Taking into consideration the geometrical arrangement of the AT transducer, axis of rotation, and the pulley system, the exact values of AT forces could be calculated. The actual measurements incorporate the use of EMG recordings of the leg extensor muscles and various external force measurements, such as long force platform or oscillating ergometers. The transducer is removed immediately after the measurements and the subjects recover.

Power transmission system

Abstract: An adjustable speed transmission according to the present invention comprises a variable speed pulley drive system and a multiple speed gear drive system. The pulley system and gear system are combined with a reversible gear system to provide a speed transmission system which is variable over a wide range of speeds while utilizing a conventional belt type speed pulley system.

Portable folding freestanding gym

Abstract: A portable, folding and freestanding exercise device/apparatus comprised of a contoured main frame made up of a pair of pivoting vertical rectangular sections, each section comprised of a pair of vertical channel-shaped frame members inter-connected at their top and lower end by horizontal curved-shaped members. A pair of pivotally mounted horizontal curved-shaped leg extensions are provided for added stability. A horizontal overhead bar is provided for the various cable configurations needed for the numerous exercises, and is affixed with a pair of pivotally mounted flat J-shaped hooks and a pair of inline pulleys for the cable. The pair of pivoting J-shaped hooks allow the overhead bar to be attached to the main frame. A horizontal frame lock/lower pulley slide bar is provided to lock the main frame and horizontal leg extensions in the open position and to accommodate the lower pulley slide. The lower pulley slide is provided for proper cable alignment with the overhead bar and the desired cable configuration and exercise. A vertical flat bar weight track mounted to the upper and lower pivot points of the pair of vertical rectangular sections is provided for the mounting of the weight tracking guide, which in conjunction with the use of the vertical weight stacking bar facilitates with keeping the barbell weights in a controlled vertical movement. Also, provided to move the desired weights thru the vertical movements of the exercises, is the weight pull bar, affixed with a portion of chain, to be connected to the desired cable configuration.

Swing-door operator system

Abstract: An operator for swing-door employs an electronic control unit for controlling the operation of a motor. The motor is bi-directionally driven at various speeds for opening, closing, braking and maintaining a given position of an associated swing-door. The motor drive shaft is mechanically connected via a timing belt/pulley system with an operator shaft for transmitting torque to a linkage assembly. The linkage assembly is configured to provide a high mechanical advantage at the fully opened and fully closed positions of the associated swing-door.

Closure and securing device, particularly for ski boots

Abstract: Closure and securing device, particularly for ski boots, composed of a lever (2,102) associated with a ski boot and having at least one winding assembly (7,107,107a) comprising: a pulley (8,108) rotatably associated with the lever (2,102) and rigidly associated in rotation with a knob (15,115,115a) which can be operated from outside, a first gear (12,112) rigidly associated in rotation with the pulley (8,108) and a second gear (13,113) rigidly associated with the lever (2,102). Releasable engagement means (14,120) being provided for mutually engaging the first (12,112) and second (13,113) gears to prevent the rotation of the pulley (8,108) with respect to the lever (2,102) and uncoupling means (21,15,118) to uncouple the first gear (12,112) from the second one (13,113) to allow the rotation of the pulley (8,108).

Control system for a continuously variable transmission

Abstract: A continously variable transmission for transmitting the power of an internal combustion engine (1) to driving wheels (19) of a motor vehicle, is described. The transmission includes a drive pulley (7) including a hydraulically shiftable disc (7a) and a first hydraulic cylinder (9a) for shifting the disc (7a), a driven pulley (8) including a hydraulically shiftable disc (8a) and a second hydraulic cylinder (6a) for operating the disc (8), and a belt (11) engaged with both pulleys (7, 8). A first hydraulic circuit (20) including a pump (21), supplys oil to the first and second cylinders (9a, 6a); and includes a transmission ratio control valve (50) for controlling the ratio provided by the belt drive transmission. A control system (70) detects operating conditions of the engine and controls transmission ratio control valve accordingly. The closure of a throttle valve of the engine and any fluctuation of engine speed are detected and the transmission ratio control valve is adjusted on the basis of the signals to change the transmission ratio.

Belt tensioner with spring actuated band brake damping

Abstract: A belt tensioning device having an improved damping mechanism for damping movements of the pivoted structure rotatably carrying the pulley with respect to the fixed structure. The damping mechanism includes a strap and a ring mounted on their respective fixed and pivoted structures and with respect to one another such that the strap engages the ring with a gripping action sufficient to provide (1) a relatively high resistance to frictional sliding movement between the strap and ring in one direction correspond to the direction of untensioning of the belt with the pulley and (2) a relatively low resistance to frictional sliding movement between the strap and ring in an opposite direction corresponding to the direction of belt tensioning. A spring is included in the mount for enabling the relatively high resistance and relatively low resistance to vary in response to the existence of predetermined vibrations such that the gripping action between strap and ring is relieved sufficient to enable movement therebetween in both directions to take place at substantially reduced resistance levels.

The mechanical efficiency of the pulley system in normal digits compared with a reconstructed system using the “belt loop” technique

Abstract: A specially designed tensiometer was employed to compare the mechanical efficiency of normal and reconstructed pulley systems in the thumb and the fingers. The "belt loop" technique for reconstruction was used in five fresh cadavers. A total of 10 thumbs and 40 fingers were dissected, and after a measured pull on the proximal tendon the yielded power output at the tip was compared with the normal and reconstructed systems. A mean of 10% loss of power in the reconstructed system in the thumb and 40% of power in the fingers, with excellent range of motion and no bow stringing was recorded.

Automatic door with automatic lock system

Abstract: An automatic door including a door body connected to a chain or belt extending between and wound around a drive pulley disposed on one side of a door opening and a driven pulley disposed on the other side thereof in which the door body is actuated to open and close by allowing the drive pulley to be rotated forwardly or reversely by an electric motor connected through a main switch and a controller to a main electric power supply source, comprises an apparatus for automatically moving the door body to its closing-stop point when the supply of electric power to the motor is interrupted by the OFF operation of the main switch, and a locking apparatus for automatically locking the door body in its closing-stop position at that time.

Multiple-function operating device particularly for ski boots

Abstract: The present invention relates to a multiple-function operating device particularly for ski boots, which comprises a containment body (1) which is associatable with a ski boot and supports a lever (2) which is accessible from the outside and is operatively connected, with the interposing of a ratchet-like assembly (6), with a central axle (7) rotatably supported by said containment body (1). The peculiarity of the invention lies in that it comprises a selector (10) which can be operated from the outside of the containment body (1) and can be selectively coupled with a first (32) and at least a second (34) winding pulley, respectively of a first (35) and a second cable (36) and the like. Members (50, 51) are furthermore provided for removably locking the rotation of said pulleys (32,34) in the direction of unwinding of the cables (35, 36).

Oriented flat belt continuously variable transmission using pulleys with guideways

Abstract: In a continuously variable belt transmission system utilizing a drive pulley and a driven pulley having logarithmic spiral guideways in the pulley disks, the balance actuator torque is reduced significantly by having the logarithmic spiral guideways connected directly to the shaft of the driving pulley in a sense opposite to that of the direction of belt movement and in the case of the driven pulley having the sense of the logarithmic spiral guideways connected directly to the shaft the same as that of the driving belt.

Torque responsive automatic bicycle transmission with hold system

Abstract: An automatic transmission for use on a bicycle is mounted on a bracket that is connected to the rear axle of the bicycle. A first chain connects the chain wheel with a sprocket fixed for rotation with the drive pulley of the transmission. A second chain transmits power from a sprocket fixed for rotation with the driven pulley to the rear wheel hub sprocket. A V-belt is used to transmit power between the driven and driven pulleys. Once a predetermined input torque is reached during pedalling, the transmission automatically changes the speed ratio between the chain wheel and the driven rear wheel of the bicycle. The gear ratio continues to change automatically and steplessly in response to increasing torque through the entire range of gear ratio change, which is approximately equal to the range provided by a standard ten speed bicycle. To selectively prevent the transmission from automatically changing the speed ratio, a hold system is provided. The hold system applies an axial force to lock the drive pulley in position, thus preventing further change in the speed ratio. The hold system can be actuated at any time during pedalling so that a desired speed ratio provided by the transmission may be maintained.

Transmission clutch closed loop slip controller and method

Abstract: A continuously variable belt-driven transmission includes a hydraulic torque converter, a variable diameter displaceable input pulley, a variable diameter displaceable output pulley, forward and reverse planetary gearing, a differential mechanism and half shafts driven from the differential mechanism. A slipping lockup clutch is hydraulically actuated to connect and disconnect selectively the impeller and turbine of the torque converter. The radial position of the drive belt that engages the input and output pulleys is determined by selectively pressurizing and venting a cylinder to move displaceable sheaves of a pulley. Hydraulically actuated clutches are selectively engageable to produce forward drive or reverse drive from the output pulley to the differential mechanism. Various sensors produce electric signals as input to a microprocessor indicate the position of the engine throttle, the magnitude of engine speed, primary pulley speed, secondary pulley speed, converter lockup clutch pressure, belt load pressure, line pressure and the position of a PRNDL gear selector. A valve body hydraulically actuates, in accordance with the output produced by the computer, the forward clutch, the reverse clutch, the torque converter lockup clutch and the displaceable sheaves of the input pulley and output pulley. An electronic feedback system controls the slip, engagement and disengagement of the torque converter lockup clutch.

Brake, particularly for the locking of tensioning elements provided in ski boots

Abstract: Brake, particularly for the locking of tensioning elements provided on ski boots, constituted by an arm eccentrically pivoted to a containment body and having a curved portion engaging the groove of a pulley adapted to wind a traction element such as a cable; an elastic means forces the arm curved portion in the groove, means being provided for the disengagement of the arm from the pulley.

Mower belt transmission with blade brake

Abstract: A transmission for a multi-blade mower has a belt trained around a driving pulley and successively around driven pulleys for the blades. For driving, an idler pulley of a tensioner engages a portion of the belt that is "downstream" from the last driven pulley and "upstream" from the first one. When the tensioner idler is disengaged from the belt for slippage of the driving pulley relative to it, blade braking is effected by opposing stationary and movable brake members mounted at opposite sides of the belt at a normally straight stretch of it that is "downstream" from the tensioner and driving pulley and "upstream" from the first driven pulley, the movable brake member then cooperating with the stationary one to clampwise engage the belt and confine it in a groove in one of those members. Manual shifting of an actuator towards an "on" position tensions a spring that engages the tensioner with the belt, and such tension, through a toggle connection, tends to maintain the actuator in that position. The movable brake member is biased towards the stationary brake member but has a lost motion connection with the actuator whereby shifting of the latter to its "on" position moves the movable brake member away from the stationary one to release the belt.

V-pulley for a continuously variable transmission

Abstract: A V-pulley is adapted for a continuously variable transmission which uses a chain belt composed of a plurality of chain blocks connected in its longitudinal direction, and a pair of V-pulleys operatively connected to each other through the chain belt. The V-pulley comprises a pair of conical pulley faces that the chain belt contacts, each of which is provided with a rough surface and a combination pattern of abrasion-prone and abrasion-resistant sections alternatively arranged at intervals shorter than the contact length and width of each chain block.

Torsional vibration damper with a V-belt pulley connected thereto

Abstract: A torsional vibration damper with a V-belt pulley unit (Front power take-off) attached to the primary part of the damper. In order to increase the service life of the damper and to improve the level of loading in the front PTO, the V-belt pulley is mounted radially and axially on a support element that is connected to the primary part of the damper. A specially designed coupling element, which contains an elastomer that has a high degree of torsional elasticity, is used in conjunction with the axial bearing. In this way, a supercritical adjustment is attained for the vibration system of the PTO, the vibration damper itself being used only for damping the torsional vibrations of the engine crankshaft.

Monitoring tension in an elongate flexible member

Abstract: A method of monitoring the tension in a flexible drive belt (1) which passes around a plurality of pulleys (2, 3) includes the steps of causing a portion of the belt (1) when installed around the pulleys to vibrate at a natural frequency and detecting that frequency. In one arrangement the belt (1) is set into a vibrating motion by an impulse and the frequency of the transient vibrations measured. In another arrangement the belt (1) is vibrated by a drive mechanism which receives a drive signal derived from the belt movement. Specific methods and apparatus for monitoring the tension are also applied to measuring the tension in elongate flexible members other than drive belts.

Automatic belt tensioner

Abstract: A belt tensioner has a shaft having an oil reservoir in a lower portion thereof and having an external thread and rotatably mounted in a body, a torsion spring provided between the body and the shaft so as to urge the shaft in a rotational direction, and a cylindrical rod having an internal thread engaged with the external thread of the shaft. A lower end of the rod being projected from the body so as to be operatively connected to a tension pulley for a belt. The torsion spring and both the threads are arranged to project rod by the rotation of the shaft urged by the torsion spring. An oil passage is provided in the shaft so as to communicate the oil reservoir with the bore above the internal thread of the rod.

Power Transmission Losses in V-Belt Drives Part 2: Effects of Small Pulley Radii:

Abstract: Run-in AV10 wrapped, raw-edged and cogged V-belts have been used to transmit power between pulleys of equal radii R equal to 51, 36 and 21 mm. Separate measurements of the torque and angular speed losses between the pulleys have shown that these are approximately proportional to 1/R and 1/R2 respectively and are also greater than expected from current theories. The maximum useful belt tension ratio fell from 21 to 5 as R was reduced from 51 to 21 mm.A dimensionless belt deformation parameter (gEI/R4)1/2, arising from a simplified analysis of torque loss, has been found empirically to correlate with both torque loss and the speed loss in excess of that expected from belt extension and radial compliance.Subsidiary tests with thick flat belts on cylindrical pulleys have shown their power losses to be unexpectedly close to those of V-belts of similar cross-sectional area, suggesting that those V-belt losses usually attributed to wedging in the pulley groove are of more general origin. It is speculated that be...

Driving and guiding apparatus for a horizontally pivoted wing

Abstract: A driving and guiding apparatus for a counter-weighed horizontally pivoted wing, particularly for a garage door. The apparatus comprises a structure embedded in an opening that the wing is designed to close, two lateral vertical guides for the wing formed in the embedded structure, an articulation rod on each side and two lateral weight-carrying cables turning around a respective pulley. The apparatus also comprises a drive means for opening and closing the wing which includes a motor-driven transmission shaft which extends along the lintel of the opening in which the wing is mounted, a pinion mounted on each end of the transmission shaft and a toothed wheel mounted coaxially and rigid in rotation with each pulley. Each toothed wheel meshes with a respective pinion so that the rotation of the transmission shaft in one direction causes controlled unwinding of the cables, and thus the opening or lifting of the wing, and its rotation in the opposite direction causes its shutting or lowering.

Power-delivery belt-tensioning system

Abstract: A first pulley is coupled by a flexible belt to a second pulley for delivering power from a source to a driven device. An idler pulley is urged against the belt to create tension therein. A cam, coupled for swinging movement to the idler pulley, faces against a cam guide in a manner to vary the spacing between the guide and the idler pulley in correspondence with the amount of swinging movement. A spring secured to the cam nudges the latter in a direction to incrementally increase the spacing between the guide and the pulley in order to maintain a pre-selected degree of tension in the belt upon the occurrence of a surge in power delivered from the source to the driven device with consequent incremental permanent stretching of the belt.

Hinged belt support and enclosure system

Abstract: A support and enclosure system for a hinged belt conveyor includes a frame truss enclosing loaded and unloaded belt flights. The frame truss includes a plurality of vertical risers. The loaded flight rides between a plurality of troughing roll sets and top idler roll sets. The unloaded flight is supported and guided by return idler roll sets. Each of the roll sets is connected distally by a clevis to mounting shafts. The mounting shafts are accepted into mounting brackets. The mounting brackets for the troughing rolls and return idler rolls include a locking bolt for fixing the position of the shafts in the bracket. The bracket for the top idler rolls includes a spring for biasing the top idler mounting shafts outward so as to bias the top idler rolls downward onto the loaded flight. Each mounting bracket incorporates a recess for accepting a first portion of a riser and a pivoting leg for engaging an opposed section of the riser. The arm and leg are biased together by a bolt which clamps the bracket to the riser. The brackets and the roll sets connected thereto are selectively positioned on the riser both vertically and rotatably by loosening the bolt, positioning the bracket, and retightening the bolt. The system also includes an orienting pulley positioned in advance of a head pulley and the tail pulley in the direction of belt travel. The orienting pulley relieves stress and prevents the twisting of the hinged belt as it travels about the head and tail pulley. The frame truss in an alternative embodiment is covered by a cap to protect the belt and its contents from the elements and to better protect to personnel from being caught in the belt.

Motorcycle front suspension and steering system

Abstract: A front suspension system for a motorcycle utilizing upper and lower wishbone type control arms set in a parallelelogram and attached to a motorcycle frame modified to facilitate mounting positions. The upper reverse wishbone is mounted from the frame to a pivot on legs above the wheel and the lower wishbone is mounted from the frame to pivoting curved bearings attached to the legs and situated at the center of the wheel. Steering is accomplished by a tensioned bi-directional chain or notched belt and connected from a fixed pulley in the top of the upright legs to a pulley on a steering shaft accommodated by the frame.

Control for continuously variable transmission

Abstract: A control for a continuously variable transmission provides an improved transient performance by restraining proportional and integral terms when an error exceeds a predetermined value range. This is effective in suppressing an overshoot in driver pulley revolution speed in approaching to its target speed. This control is provided with a safeguard against break down of a vehicle speed sensor such that the above mentioned restrain is removed when the vehicle speed indicative signal should drop to zero during running of the vehicle.

Twisted flat belt drive for line shaft conveyors

Abstract: A twisted flat belt drive arrangement transfers rotation between nonparallel shafts. A toothed pulley or gear is affixed to each shaft, and a pair of smooth surfaced idler rollers are mounted to rotate independently on an idler shaft positioned between the two shafts. An endless, flat, toothed belt has end loops meshed with the gears and middle portions twisted to contact a smooth outer surface of the belt with the idler rollers. The twisted flat belt drive arrangement is applied to transferring rotation from a main conveyor line shaft to a line shaft of a branch conveyor intersecting the main conveyor. The arrangement is also applied to providing driving rotation to diverter rollers of a diverter mechanism through an intermediate transmission shaft parallel to the main line shaft. The drive arrangement may be implemented for both purposes on the same conveyor to power diverter rollers of a mechanism which diverts articles onto a branch conveyor which is also powered from the main conveyor line shaft.

Power takeoff shaft arrangement for a road vehicle

Abstract: A power takeoff attachment for a conventional road vehicle includes a base member with a rod extending transvesely thereto and of a length so that the outer end thereof can be inserted into a pivot coupling for example provided by a V-shaped space between the torsion bar bracket and the frame of the vehicle. A rear edge of the base can be bolted to the transverse beam of the frame of the vehicle with the angle of the base being adjusted by the bolted connection. The base carries bearing blocks which support the power takeoff shaft and in one example an electric clutch. Drive is communicated to the shaft via chain or belt coupling from a sprocket mounted at the pulley of the vehicle engine and attached to the pulley by bolts which pass into the pulley and into the crank shaft. The power takeoff shaft including a splined recess is exposed at a front end of the vehicle and can be used to drive an implement for example a snowblower or pump which can be slid rearwardly onto sleeve-shaped brackets carried on an underside of the vehicle frame. In another example, an electric clutch is mounted at the pulley.

Rear derailer for bicycle

Abstract: PURPOSE: To reduce the protruded amount of a tension pulley in a lower side and to make uniform gaps between a guide pulley and sprockets by pivotally attaching linking members via a pair pivotal support shafts supporting guide and tension pulleys on the other end side thereof and arranging the guide pulley in the attaching part front of a base member. CONSTITUTION: A pair of linking members 2 and 3 extended in upper and lower directions are extended horizontally in a position extended forward from the attaching part 11 of a base member 1, and pivotally attached via a pair of pivotal support shafts 7 and 8, the outer end parts thereof being inclined forward with respect to inner end parts. A guide pulley 5 supported on a movable member 4 pivotally attached to these linking members 2 and 3 is arranged before the attaching part 11 of the base member 1. Thus, the sufficient chain take-up amount of each sprocket is secured, the protruded amount of a tension pulley 6 against the base member 1 in a lower direction is reduced and, by the inclination of the pivotal support shafts 7, 8, 9 and 10, gaps between the guide pulley 5 and the sprockets are made uniform.

Continuously variable transmission belt and pulley arrangement

Abstract: A belt and pulley construction for use in a continuously variable power transmission arrangement. In one embodiment the conical working surfaces of the drive pulleys and the driven pulleys are comprised of removable segments formed of relatively erodable friction modifying material so that the conical pulley surfaces will wear away before the drive belt. In another embodiment the drive belt, whether comprised of a rubber compound or of metal, contains wear faces or pads which contain friction modifying material. Traction between the belt and the pulleys can thus be controlled by members other than solely through the tension of the drive belt.