Abstract: A tensioner for toothed belts comprises a hydraulic fluid filled cylinder having a piston with a rod projecting out of the cylinder and engaging a pivoted arm with a roller at one end for engaging the belt. A spring within the cylinder urges the rod in the projecting direction, and a check valve carried by the piston allows the rod to project rapidly to take up slack in the belt. Hydraulic fluid, however, flows through the small clearance between the piston and the cylinder wall as the rod retracts, and therefore limits the rate of retraction. A path is provided between seals surrounding the rod to route air directly to the reservoir so that it does not enter the fluid chambers within the cylinder. The piston material is chosen to expand more rapidly than the cylinder with increasing temperatures to reduce variations in leak-down time.

Abstract: A tension providing device which enables to prevent the invasion of dust and water into a casing together with enabling the locking and the winding off of the torsion spring from the base side of the casing. This device is characterized by being provided with a rotatable shaft in the casing which only rotates by restraining the sliding in the axial direction of the casing, screwing the pushing body which slides by the rotation of the shaft with the shaft, supporting this screwed portion with bearing, and further screwing a seal bolt at the base portion of the casing.

Abstract: A combination of a power transmission belt that is to be operated in an endless path and a tensioner for the belt is provided, the tensioner comprising a support unit fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, and a mechanical spring unit operatively associated with the support unit and the belt engaging unit urging the belt engaging unit relative to the support unit in a belt tensioning direction and against the belt with a force to tension the belt, the spring unit being arranged to increase its urging force on the belt engaging unit as the belt engaging unit moves in the belt tensioning direction relative to the support unit throughout the entire normal tensioning range of movement of the belt engaging unit relative to the support unit.

Abstract: A method of making a tensioner for a power transmission belt that is adapted to be operated in an endless path is provided and comprises the steps of providing a support unit for being fixed relative to the belt, providing a belt engaging unit to be carried by the support unit and be movable relative thereto, operatively associating a mechanical spring unit with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, operatively associating a fluid dampening unit with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction thereof, forming the mechanical spring unit to comprise a pair of springs disposed in substantially parallel spaced relation, disposing at least a part of the fluid dampening unit between the springs and in substantially parallel relation therewith, and forming the fluid dampening unit to compris

Abstract: A radiator-fan system, particularly for buses with rear-mounted engines, with the system being fitted with a bevel gear drive and notwithstanding larger dimensions, being accommodated in the restricted space of the engine compartment of the vehicle.

Abstract: A carriage for use in disc driving or the like can be driven correctly by a carriage driving apparatus comprising guide shafts extended linearly, a carriage slidably supported on the guide shafts, a pulley holder rotatably supported around one of the guide shafts at one end thereof, a driven pulley rotatably journaled at one side of the pulley holder, a drive pulley disposed at a predetermined distance from the driven pulley and connected to a rotational shaft of a driving motor, a pulling belt laid around between the drive pulley and the driven pulley and connected at an intermediate portion thereof to the carriage and a base for supporting the guide shafts, wherein a pulley holder rotation inhibitive portion is disposed on the opposite side of a mounting portion for the driven pulley with respect to the guide shaft support portion of the pulley holder closely opposing to the base.

Abstract: A hydraulic autotensioner of a sealed type is used to give tension to a belt or a chain. The hydraulic autotensioner includes a body member having a large diameter oil chamber, a plunger having a small diameter oil chamber and a small passage, a piston whose head extends outside the body member and a spring for biasing the plunger.

Abstract: A belt sander having a vertically slotted casing for receiving an idler shaft; a crowned idler pully rotatably mounted on the idler shaft; a crowned, power driven drive pully rotatably mounted on the casing; a guide shaft attached perpendicular to the idler shaft; a first alignment plate attached to the casing interior; a second alignment plate slideably mating the casing interior between the first alignment plate and the idler shaft, said plates being bored to slideably receive the guide shaft; and a spring mounted in compression between the alignment plates.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path and a method of making the same are provided, the tensioner comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction of movement thereof with a restricting force of the dampening unit.

Abstract: In a V-belt drive, the driven sheave is carried on a frame pivoted so that center distance between driver and driven sheaves can change. The position of the frame pivot is chosen so that the torque reaction of the driven load results in an induced torque about the pivot axis tending to increase belt tension appropriately as the driven load increases.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path and a method of making the same are provided, the tensioner comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction of movement thereof, the dampening unit comprising a piston unit and a cylinder unit having the piston unit therein and defining two chambers for fluid in the cylinder unit on opposite sides of the piston unit.

Abstract: A radial belt grinder having a drive wheel and a camber adjustable idler wheel coupled by a housing assembly. The housing assembly is rotatably supported on a machine radial groove by four shoulder bolts which also function to attach a C-framed motor to the base ring plate. A closed loop abrasive belt is transported about the wheels to accomplish multiple position platen and contour wheel grinding. An anti-recoil control mechanism facilitates belt exchanges and limits pressure recoil when the idler wheel is used in tilt angle, contour wheel grinding. A universal work rest arm, centrally supported at the rear of the housing assembly, provides the structure to adjustably support the work piece in infinite radial work positions through 180 degrees. A quick set friction lock functions to secure the rotatable housing at a selected radial angle. The work rest and all guards are reversable to accommodate left or right hand machine operations.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path is provided and comprises a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction of the movement thereof, the fluid dampening unit comprising a piston and cylinder unit.

Abstract: Carriage drive means having cables or belts for transmitting drive force and a spring for tensioning the cables or the belts. A rigid member interposed between the spring and the cable or belt, the rigid member constituting a self-locking mechanism which allows the member to move, when elongation occurs in the cable or belt, to a position in which the elongation is absorbed by the tension of the spring, but does not allow same to move in a direction in which it is restored to its original position.In the aforesaid self-locking mechanism, the rigid member may be in the form of a segmental cam which engages with suitable friction the shaft of a pulley mounted for movement while having the cable wound thereon, or the rigid member may engage with suitable friction a pivotal member for supporting in a position remote from the pivot the pulley having the cable wound thereon.

Abstract: A first shaft is screwed with a second shaft. The first shaft is secured rotatively to a bearing through a spring and the second shaft is secured slidably to another bearing. A pushing force in a fixed direction is provided to the second shaft through the screwed portion by actuating a spring torque in a rotative direction to the first shaft, whereby a determined tension is given to a chain when a tensioner is slackened in use.

Abstract: A tension providing mechanism including two shafts, one having an external screw and the other having an internal screw, the shafts being connected by engaging the screwed portions with each other. One of the shafts is supported for axial translation without rotation, and the other shaft is supported for rotation and is restrained from axial sliding. The rotatable shaft includes a torsion spring for applying spring torque in a direction to cause the other shaft to extend in an axial direction against a member, such as a drive chain, in order to increase the tension thereof. A locking mechanism is provided for constraining movement of the rotatable shaft, the locking mechanism being in the form of a lever having one end removably engaged with a split groove provided in the end of the shaft, the other end of the locking mechanism being latched to a projection formed on the case in which the tension providing mechanism is housed.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path and a method of making the same are provided, the tensioner comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid operated transmitting unit operatively associated with the spring unit and the belt engaging unit for translating motion therebetween whereby the spring unit is adapted to be disposed remote from the belt engaging unit.

Abstract: A tensioner for a power transmision belt that is adapted to be operated in an endless path and comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction of movement thereof, the fluid dampening unit comprising a piston and cylinder unit. The mechanical spring unit comprises a pair of coiled compression springs with their longitudinal axes disposed in substantially parallel side-by-side spaced relation.

Abstract: A chain tensioner comprises a plunger yieldably urged and displaceable in one direction to transmit chain tensioning force to a chain, and a wedgable means co-acting with the plunger to block its retraction. Body structure associated with the plunger and wedgable means may incorporate an outer body and an inner body movable relative to the outer body and defining a ramp surface engaging the wedgable means.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path and comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction of movement thereof, the fluid dampening unit comprising a piston and cylinder unit. The mechanical spring unit comprises a pair of coiled compression springs with their longitudinal axes disposed in substantially parallel side-by-side spaced relation.

Abstract: A device for tensioning the endless drive belt for vehicle accessories. A housing is mounted in a fixed position adjacent the drive belt. A shaft assembly is slidably mounted in an axial bore formed in the housing and includes a stub shaft portion extending outwardly from the housing through a slot formed in one of the housing walls. An idler pulley is rotatably mounted on the stub shaft and is moved into tensioning engagement with the drive belt by a compression coil spring which is adjustably mounted in the housing bore by a spring guide. The spring slidably moves the shaft assembly in a belt tensioning direction within the housing bore. Concavely curved surfaces are formed in certain areas of the shaft assembly within the housing. Roller means are interposed between and are biased by a spring into a wedging relationship with the curved shaft surfaces and adjacent housing walls.

Abstract: A tensioner for an endless power transmission belt is provided wherein such belt is employed in driving a sheave comprising at least one accessory which upon being driven creates a slack side and a tight side in the belt on opposite sides of the sheave and the tensioner comprises, a first support arm having pivot means, a first idler pulley rotatably carried by the arm, and a pivot pin extending through the pivot means and supporting the first arm adjacent the sheave with the first pulley engaging the slack side to enable tensioning thereof; and, the tensioner further comprises a second support arm supported by the pivot pin, a second idler pulley rotatably carried by the second arm and engaging the tight side of the belt, and means connecting the second arm to the first arm to thereby move the first arm and its pulley into belt tensioning and dampening engagement against the slack side once the tight side of the belt moves the second pulley and second arm.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path is provided and comprises a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a fluid dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction thereof. The mechanical spring unit comprises a pair of springs disposed in substantially parallel spaced relation with the fluid dampening unit having at least a part thereof disposed between the springs and in substantially parallel relation therewith, the fluid dampening unit comprising a rotary dampening unit.

Abstract: A tensioner for a power transmission belt that is adapted to be operated in an endless path and a method of making the same are provided, the tensioner comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a mechanical spring unit operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, the mechanical spring unit providing the sole force of the tensioner for tensioning the belt, and a fluid dampening unit operatively associated with the support unit and the belt engaging unit to dampen the movement of the belt engaging unit relative to the support unit in at least one direction of movement thereof with a restricting force of the dampening unit.

Abstract: A device for tensioning the endless drive belt for vehicle accessories. An L-shaped housing is mounted in a fixed position adjacent the drive belt. A stub shaft is slidably mounted on the housing and has an idler pulley rotatably mounted on an extended end of the shaft. A pair of cam plates having mutually engageable camming surfaces are slidably mounted in the housing. One of the plates is operatively engaged with the stub shaft and imparts sliding movement to the shaft for moving the idler pulley into tensioning engagement with the drive belt. A compression spring biases the camming plates into sliding engagement with each other moving the pulley toward tensioning engagement with the drive belt. The included angles of the cam plate camming surfaces equal 90.degree.

Abstract: A belt tensioning device including a mounting bracket, a pulley support arm pivotally mounted at one end on the mounting bracket and having an idler pulley rotatably mounted at its other end. A spring yieldably biases the arm in a direction to press the idler pulley against the belt. The arm has opposed wall faces disposed in planes perpendicular to the pivot axis of the arm and mounted on the bracket and have pad faces pressed into engagement with respective ones of the opposed wall faces on the arm to dampen vibration or oscillation of the arm.

Abstract: A belt tension controlling mechanism has a spring member which operates on a pulley support bracket to establish a tension in a belt trained on the pulley. The spring member surrounds a threaded sleeve which is rotated by a pair of selectively operable one-way ratcheting clutches which are simultaneously driven in opposite directions by a vacuum motor. The rotation of the sleeve results in linear meovement of a shaft connected to the pulley support bracket to thereby increase or decrease the belt tension, depending upon which clutch is operable.

Abstract: A music teaching apparatus, useful for requiring the student to play notes in correct relative timing and suitable for employment on a piano, includes a holder for sheet music, a continuous transparent web having a plurality of opaque covering sections thereon, such as strips of pressure sensitive tape of substantial width, so as to be capable of covering at least one note "width" and preferably more, with such opaque sections being positioned to permit (and require) continuous reading and playing of the music by the player ahead of the covering sections when the web is moved across the music, and means, such as a pair of vertical cylinders about which the web is held in tension, for continuously moving the web across the music and in contact with it or close to it (so as to prevent optical distortions). Preferably, individual opaque sections extend over a treble staff and a corresponding bass staff but do not extend to other treble and bass staffs. A method of teaching music is also disclosed.