Abstract: An automatic hydraulic tensioner according to the present invention is provided with a communication mechanism for allowing a space radially inside a plunger-side end wire portion of a coil spring to communicate with a small clearance between the plunger and a cylinder. This automatic hydraulic tensioner thus succeeds, with a simple structure, in preventing bubbles from remaining within a pressure chamber and appropriately maintaining the tension applied to a power transmitting means such as a belt, a chain or the like.

Abstract: A hydraulic tensioner with an internal reservoir. The tensioner includes a housing having a sleeve, and a hollow piston slidably received about the sleeve and biased in a protruding direction by a spring. A fluid chamber is defined by the sleeve and the hollow piston. Fluid from an external source flows through a passageway into a reservoir which is located inside the tensioner housing above the fluid chamber. The reservoir is connected to the fluid chamber such that fluid flows from the reservoir through a check valve assembly into the fluid chamber such that the fluid chamber remains filled with fluid.

Abstract: A hydraulic tensioner 10 includes a piston rod 12 slidably fitted in a cylinder 14 with a small gap or clearance therebetween, and a housing 16 containing the cylinder 14. A ball seat 20 is press-fitted in an end of the cylinder 14 opposite to the piston rod 12 so as to define within the cylinder 14 a high pressure oil chamber 21. The housing 16 has a partition wall 26 at a substantially central portion thereof. The cylinder 14 is loosely fitted in the housing 16 with its longitudinal portion extending forwardly from the partition wall 26. The partition wall 26 has an oil passage 32 having an inside diameter smaller than the outside diameter of the ball seat 20, so that the cylinder 14 and the ball seat 20 are in abutment with the partition wall 26 of the housing 16. A force tending to retract the piston rod 12 generates a pressure which acts on the partition wall 26 either directly via a spring 24 and the cylinder 14 or via the high pressure oil chamber 21 and the ball seat 20.

Abstract: A tensioner for adjustably exerting tension upon a flexible member such as a chain or belt. The tensioner comprises a housing having a piston cavity with an actuating piston reciprocally mounted therein. A spring biases the piston in a direction outwardly of the housing. Both the piston and the housing carry a guide shoe thereon for engaging the flexible member. The piston has a flat face cut therein that defines a first stop and a second stop. A pin is positioned parallel to the flat face to restrict axial movement of the piston to within the constraints of at least one stop, and to also prohibit rotational movement of the piston within the cavity.

Abstract: A tensioner mechanism adapted for placing tension in a drive belt of a mower deck, the tensioner including an elongate member operatively coupled with an idler arm, and slidably mounted with a support member operatively carried by the mower deck. A compression spring carried on the elongate member between the idler arm and the support member operatively presses the idler arm away from the support member and is completely compressed during normal mowing operations for generally blocking the idler arm from swinging toward the support member during operation. A threaded member within which said elongate member is slidably received is adjustably fixed with the support member by a pair of nuts that can be adjusted on the threaded member to alter the position of the threaded member with respect to the mower deck for adjusting the tension that the idler pulley places in the belt during normal mowing operations.

Abstract: In a hydraulic tensioning arrangement for tensioning a flexible drive for a camshaft of an internal combustion engine including a crankcase and a cylinder head wherein a main lubricating oil channel extends longitudinally along the inside of the crankcase and has an opening at the front end of the crankcase, a hydraulic housing with a cylinder receiving a plunger is mounted on the front end of the crankcase so as to cover the main lubricating oil channel opening and passage elements are provided for supplying oil from the main lubricating oil channel to the cylinder to bias the plunger against tensioning elements engaging the flexible drive.

Abstract: A mechanical tensioner having a piston biased by a spring in a protruding direction. A ratchet assembly includes a spring, a ratchet piston, and a pair of ratchets may also provide a no-return function. A plurality of belleville disc springs provides the force on the tensioner piston, the ratchet piston, or both.

Abstract: A chain tensioner keeps constant the tension of a chain for transmitting the rotation of an engine crankshaft to e.g. camshafts. It includes a housing having a cylinder chamber. A rod member has its rear end inserted in the cylinder chamber for pressing a chain. A tension adjusting spring biases the rod member outwardly of the housing. The chain tensioner further includes a hydraulic damper for damping a dynamic load applied to the rod member from the chain, and a thread engagement mechanism for preventing the rod member from retracting under a static load applied to the rod member.

Abstract: The proposed chain tightener is provided with a damping piston (3) in a guide bore (2). A stop ring (8) is provided between the damping piston (3) and the housing (1). The stop ring (8) cooperates with grooves (9, 17, 13) and stops (11, 10, 14) on the housing (1) and on the damping piston (3), preventing the damping piston (3) from sliding too far into the housing (1). To allow the damping piston (3) to be locked in position in the bore (2), it is proposed that the stop ring (8) should be clamped in a locking position between two contact surfaces (12, 16) on the housing (1) and damping piston (3) respectively, the contact surfaces (12, 16) being inclined in relation to the axis of the damping piston.

Abstract: A hydraulic tensioner for operation of a dual chain system including at least one piston maintaining force on two chain guide arms. One embodiment includes an inner and outer piston with a first spring within the bore and a second spring on top of the housing, where each piston contacts a chain guide arm. A second embodiment includes one piston with a fulcrum arm contacting the chain guide arms. A third embodiment includes two pistons arranged side-by-side sharing the same chamber and check valve assembly.

Abstract: A hydraulic tensioner having a slidable plunger in a housing, a shaft stopper ring on the rear-end of the plunger, and a stopper screw fastened to the housing that can engage with the shaft stopper ring at the retracted position of the plunger. Packing is provided to seal a clearance between the stopper screw and the housing when the stopper screw is in its engagement position with the housing.

Abstract: An improved chain tensioner device having a small outside shape or profile and a relatively small number of components which can be assembled with a small number of steps. A tensioner body 2 slidably mounts a plunger 4 which carries a shoe 7 for engaging the chain. The shoe 7 has an extension strip 12 formed integrally therewith and extending over a guide surface 11 on the body 2 for preventing the shoe 7 from rotating about the axis of the plunger 4. A pin locking hole 13 is formed in the guide surface 11 and the extension strip 12 has a pin receiving through-hole 14 formed at a position which can be aligned with the pin locking hole 13. A stopper pin 15 is fitted through the pin receiving through-hole 14 into the pin locking hole 13, thereby locking the shoe 7 in position against movement relative to the tensioner body 2 during installation.

Abstract: A hydraulic chain tensioner has a check valve vent. The tensioner includes a housing having a bore with a fluid filled chamber, a hollow piston slidably received within the bore and biased in a protruding direction by a spring, and a check valve assembly which permits fluid to flow from an external source through the valve and into the fluid filled chamber. The vent includes a disc positioned against the inlet from the external source of fluid. The disc has at least one channel formed on the surface of the disc facing the external source. The channel has a first end at the periphery of the disc and a second end at the center point of the disc.

Abstract: A hydraulic autotensioner has a cylinder having a closed bottom end, a sleeve mounted in the cylinder and a plunger slidably mounted in the sleeve. The interior of the cylinder is divided into a reservoir chamber and a pressure chamber by the plunger which is formed with a passage through which the reservoir chamber and the pressure chamber communicate with each other. A check valve is provided in the passage to close the passage if the pressure of hydraulic oil in the pressure chamber increases above the pressure of hydraulic oil in the reservoir chamber. A return spring is mounted in the cylinder to bias a rod which is axially movable together with the plunger in such a direction as to protrude from an upper opening of the cylinder. The return spring is mounted in a space formed between the outer peripheral surface of the sleeve and the inner peripheral surface of the cylinder.

Abstract: A drive system for driving at least one and preferably, a plurality of driven components. The drive system includes a multi-drive plate for securedly mounting and accurately positioning a plurality of drive system components on a single support structure. The drive system also has a single drive belt for being driven by at least one driving member. The multi-drive plate supports and aligns pulleys connected to the driving member and the driven component so that the single drive belt drives at least one driven component. The driving device may include a clutch for allowing the drive system to be driven by a main driving device or by an auxiliary drive device. The driving device and the at least one driven component are mounted on the same side of the multi-drive plate. The pulleys attached to the driving device and the at least one driven component and the serpentine belt are mounted on another side of the multi-drive plate so that the serpentine belt is easily accessible.

Abstract: The tensioner includes a body (12) defining a blind cylindrical cavity (14) and a piston (20) slidably mounted in the cavity (14) and adapted to bias a pressure shoe (24) into contact with the endless connection element (26) so as to put the latter under tension. The inner end (18) of the cavity defines an orifice (28) for connection to a source of liquid under pressure and closable by a resilient blade (36) constituting a check valve.

Abstract: A hydraulic autotensioner having a close-bottomed body in which is sealed hydraulic oil. A plunger is slidably mounted in the body with a gap formed therebetween through which the hydraulic oil can leak. The plunger is formed with a hole in the top thereof, and a return passage extending through the plunger from the bottom of the hole to the bottom of the plunger. A rod, having its bottom end inserted in the hole, is provided with a rod spring for biasing the rod in such a direction so as to protrude out of the body. A plunger spring is provided for urging the plunger against the bottom end of the rod. Also, a valve seat is provided on the bottom of the hole so as to be brought into close contact with the bottom end of the rod. The return passage is opened and closed by axial displacement of the rod relative to the valve seat.

Abstract: The characteristics of the auto-tensioner of the present invention resides in a second reservoir chamber 24 which resides within a plunger 11 extending toward inside of a spring 15.Accordingly, without changing the whole length of a cylinder 10, sufficient amount of operating oil can be reserved and the smooth flow of operating oil into a pressure chamber 23 from the second reservoir 24 chamber can be conducted.

Abstract: A belt tensioner, an actuator therefor and methods of making the same are provided, the actuator of the tensioner having a rotatable shaft that is operatively interconnected to a spring and is provided with opposite ends one of which is operatively interconnected to a piston, the actuator having a casing provided with an internal recess therein that receives the other end of the shaft therein, the spring being adapted to rotate the shaft to extend the piston while the other end of the shaft rotates in the recess and bears against an end surface thereof, the other end of the shaft comprising a thrust washer assembled to the shaft to be carried thereby.

Abstract: A conveying device for transportation of extended line products such as cables or tubes has tension elements to exert a tension force on at least two tension chain wheels in the direction away from the driving chain wheels. A self-locking wedge prevents the tension chain wheels from moving back and forth. The automatic adjustment of the roller chains reduces wear of the conveying device and prevents speed changes during transportation of the extended line product.

Abstract: A hydraulic autotensioner has a cylinder having a closed bottom end, a sleeve mounted in the cylinder and a plunger slidably mounted in the sleeve. The interior of the cylinder is divided into a reservoir chamber and a pressure chamber by the plunger which is formed with a passage through which the reservoir chamber and the pressure chamber communicate with each other. A check valve is provided in the passage to close the passage if the pressure of hydraulic oil in the pressure chamber increases above the pressure of hydraulic oil in the reservoir chamber. A return spring is mounted in the cylinder to bias a rod which is axially movable together with the plunger in such a direction as to protrude from an upper opening of the cylinder. The return spring is mounted in a space formed between the outer peripheral surface of the sleeve and the inner peripheral surface of the cylinder.

Abstract: A belt tensioner, an actuator therefor and methods of making the same are provided, the actuator of the tensioner having a rotatable shaft that is operatively interconnected to a spring and is provided with opposite ends one of which is operatively interconnected to a piston, the actuator having a casing provided with an internal recess therein that receives the other end of the shaft therein, the spring being adapted to rotate the shaft to extend the piston while the other end of the shaft rotates in the recess and bears against an end sumtrace thereof, the other end of the shaft comprising a thrust washer assembled to the shaft to be carried thereby.

Abstract: An oil-operated tensioner is constructed with an internal cylinder which receives a rod in such a way that the rod itself serves as a piston, and the diameter of the high pressure chamber formed by the rod and the cylinder is the same as that of the rod. This configuration eliminates changes in the volume of the low pressure oil chamber of the tensioner, maintains substantially constant oil pressure in the low pressure chamber, and substantially reduces the tendency of air to be drawn into the low pressure chamber as a result of flow of oil out of the low pressure chamber when the rod moves in the protruding direction. A piston on the rod in the low pressure chamber, but spaced from the wall of the chamber by a gap, exerts a positive pressure on the oil as the rod moves in the protruding direction to provide further assurance against the entry of air.

Abstract: A hydraulic tensioner having a piston slidably fitted in a piston cavity and biased in a protruding direction by a spring and fluid. The piston is cylindrical and has a conical bottom surface. A check valve permits fluid to only flow into, and thereby protrude the piston, but not out of the cavity. Air may be vented out of the cavity through the clearance between the piston and the interior wall of the housing. This clearance is dimensioned so that air may be vented from the cavity without a significant loss of fluid. The conical bottom surface of the piston is configured to force any air present in the cavity to the clearance and thus out of the tensioner.

Abstract: A hydraulic belt tensioner operating on pressurized lubricating oil in an internal combustion engine. The tensioner includes a ratchet mechanism which locks the output member of the tensioner in a fixed position when the engine is not operating and which is disengaged when the engine is operating and the lubricating oil is pressurized. A seal is provided to prevent oil from escaping from the unit. The invention further includes slots formed in a plunger element of the tensioner which are effective to dissipate air which tends to become entrapped under the plunger when the engine is initially started.

Abstract: A vibration proofing system for an engine timing chain utilizes a tensioner on the slack side of the chain path, in which a ring-shaped, chain-engaging shoe is rotatably disposed on a circular frame mounted on the piston of a tensioner mechanism, and in which the shoe surrounds the frame and tensioner mechanism. Engine oil, which is used in the tensioner, is supplied from the tensioner to lubricate the rotatable chain-engaging shoe.

Abstract: In an oil-operated tensioner having a cylindrical housing and a plunger defining a high-pressure oil chamber, air is prevented from entering the high-pressure chamber, as the plunger moves in the outward direction, by oil in an annular chamber formed in the interior wall of the housing and surrounding the plunger. The annular recess can be formed at the end of the housing, if the housing is disposed so that the plunger projects outwardly in the upward direction. Otherwise, the annular chamber is disposed inwardly from the end of the housing.

Abstract: A chain tensioner utilizing oil as an operating fluid comprises a housing having a vertical bore and a plunger projecting upward through an opening at the upper end of the bore and urged by a spring in the projecting direction. The plunger has an internal oil reservoir formed near its upper end, a passage leading from the reservoir to a high-pressure oil chamber formed by the housing and plunger, a check valve preventing flow from the high-pressure chamber to the reservoir, and an opening permitting flow of oil into the reservoir. A second oil reservoir, annular in shape, is formed in the housing at the location of the opening to provide an oil seal between the plunger and the wall of the bore. This oil seal prevents air from flowing between the plunger and the wall of the bore into the high-pressure chamber. In one embodiment, an auxiliary spring is located in the second oil reservoir.

Abstract: In a fluid tensioner of the piston and cylinder type an annular element is provided either on the piston or on the wall of the cylinder. In the case of an annular element on the wall of the piston, the annular element has a coefficient of linear expansion greater than that of the wall of the cylinder. In the case of an annular element on the wall of the cylinder, the annular element has a coefficient of linear expansion less than that of the piston material. In both cases, the annular element provides compensation for changes in hydraulic fluid viscosity to maintain a constant leak-down rate, allows for flexibility in the choice of piston, rod and cylinder materials.

Abstract: A device for applying tension to an endless chain, belt or the like comprises a ratcheted plunger having a substantially planar face disposed in substantially perpendicular relationship to the axis of movement of the plunger, and a chain or belt-engaging lever having a pad with a convex face arranged to contact the substantially planar face of the plunger. Vibrational forces exerted by the lever on the tensioner are substantially parallel to the axis of movement of the plunger, so that wear of the plunger and plunger guide are significantly reduced.

Abstract: A belt tensioning device for a belt sander is disclosed in the form of a guided U shaped saddle permitting economies in manufacture associated with external milling of the cantilever extension bar of a small belt sander for use with handheld power tools.

Abstract: A hydraulic fluid tensioner for a toothed belt, having a piston with a piston-carried ball and seat check valve, utilizes a ball pressing spring having a spring force more than 30 times the weight of the ball and less than 60% of force resulting from the hydraulic pressure acting on the ball and urging the check valve open as the piston moves in the projecting direction. The spring force prevents rapid accelerating movement of the piston, or vibrations of the tensioner, from causing irregular piston movements resulting in noise and vibration.

Abstract: An engine equipped with driving belts is provided with an automatically regulated belt-stretching device, arranged in the vicinity of one belt, mounted on a support fixed to the engine. The device includes a pin extending from the support and defining a longitudinal axis, the pin being provided with a pair of shoulders at a distance from one another, between which two bushings are inserted. The bushings are adaped to define, together with the pin, a pair of housings. Springs capable of displacing the bushings relative to the shoulders and to the longitudinal axis of the pin are housed in the respective housings. A bearing which rotates in contact with one belt is provided on the outer surface of each bushing.

Abstract: A tensioner for a power transmission belt is disclosed comprising a return spring associated mechanically with a tensioner roller with which the belt cooperates for controlling the movement of said roller under the action of said spring, wherein the vibrations likely to arise in the belt are damped by a rubber sheath integral with said spring for forming a chamber closed at its ends by seals, one at least of which has a nozzle for the inlet and/or outlet of air into and/or out of the chamber defined by said sheath and said seals.

Abstract: A tensioner for a power transmission belt or the like includes a housing providing an elongated interior cavity opening out of one end of the housing and a piston positioned within the cavity for movement therealong for dividing at least a part of the interior cavity into first and second variable-volume chambers for holding hydraulic fluid wherein the second variable-volume chamber is closer to the one housing end than is the first variable-volume chamber. The tensioner utilizes a distensible bellows section connected between the piston and the housing for separating the second variable-volume chamber from the cavity opening at one end of the housing. A plunger is connected to the piston and extends out of the one end of the housing, and a spring is interposed between the piston and the housing for biasing the piston toward the one end of the interior cavity so that the plunger is urged out of the one housing end.

Abstract: A tensioner to be used keeping a cap of a tension rod up for tensioning a belt or chain wherein an air vent releasing an inner pressure of a casing by a vertical orifice formed on the center of the cap of tension rod and connected with a horizontal orifice formed through the cap and the tension rod. A spring pin is inserted into the horizontal orifice keeping the abutted edges thereof up so as to prevent a leakage of lubrificant.

Abstract: A tensioner for vehicle belts produces reduced rattling because radial forces are not transferred to the plunger. A tensioner body has a columnar hole extending from an open end toward a closed end. The plunger is fitted into the columnar hole and separates the columnar hole into first and second chambers. The plunger has sufficient clearance with respect to the body to permit restricted passage of fluid between the chambers. A rod pressed by the belt extends into the columnar hole and presses the plunger against the biasing force of a spring. In order to reduce the transfer of radial forces from the rod to the plunger, either the lower surface of the rod or the upper surface of the plunger is formed in a semi-spherical shape.

Abstract: A joint structure for an industrial robot is provided with a gear transmission mechanism to drive movable robot element, such as a swivel body (14), of an industrial robot. The joint structure comprises a driven gear (26) connected to the movable robot element, two drive pinions (28, 30) in mesh with the driven gear (26), respectively, at different positions on the driven gear (26), a belt transmission mechanism (28a, 30a, 32) operatively connecting the two drive pinions (28, 20), a tensioner (36) for adjusting the tension in the power transmission belt (32) of the belt transmission mechanism (28a, 30a, 32), and a rotative drive source (34) connected to one (28) of the two drive pinions (28, 30).

Abstract: A belt or chain tensioner comprising a tube type casing provided with a plurality of through holes, wherein a sleeve, a cup type tension rod and a compression spring are mounted from the rear end of casing and detachably supported by a plug screwed in the casing so as to permit the urging tension rod to be locked at various stages of extension.

Abstract: While chain tensioners are used with chains on the engine of a motor vehicle, conventional blade spring configurations do not apply consistent forces throughout the life of the chain. The chain tensioner comprises two blade springs mechanically interlocked within a shoe, the shoe being adapted to contact the chain of the motor vehicle. The two blade springs each have a minimal form radius that is substantially smaller than the minimal form radius of a single blade spring, the single blade spring being otherwise identical to the two blade springs, and the thickness of the single blade spring being the same as the combined thickness of the two blade springs.

Abstract: A belt or chain tensioner has a tension rod which is urged by a compression spring. The forward stroke of the tension rod is normally released and the backward stroke of tension rod is locked normally by a locking component and released only when the retreating force of tension rod, due to the counterforce of the belt or chain, exceeds the gripping force of the locking component.

Abstract: An autotensioner which is designed to apply appropriate tension to a timing belt of an engine or a belt that drives auxiliary machinery, for example, an alternator, compressor, etc. The autotensioner has an annular space that is partitioned into two chambers by a first partition wall which is provided on a fixed member and a second partition wall which is provided on a pivoting member, the annular space being filled with a viscous fluid. The first partition wall is formed with a passage which provides communication between the two chambers, and a check valve is provided in the passage. The check valve closes the passage when the tension in the belt increases suddenly, to resist the pivotal movement of the tensioner in one rotational direction, thereby enabling the tensioner to follow slowly and effectively the movement of the belt in which the tension is suddenly increased.

Abstract: A self-adjusting chain tensioning device comprising a spring loaded rubbing block in continuous contact with said chain. Shims are used to preload or pre-compress said spring or springs. The rubbing block and shims are horizontally fixed but vertically slideable within an inner slide plate and an outer slide plate. Means to fixably position the inner slide plate and outer slide plate are provided.

Abstract: An endless track assembly for a vehicle includes a support plate having an elongated, horizontal guide slot formed in one end thereof. A support is slidably mounted in a guide groove and an idler sprocket is rotatably mounted on a support. The drive sprocket is rotatably mounted at the other end of the support plate and an endless track is entrained about the two sprockets. A spring is mounted between an abutment on the movable support member and an adjustable abutment member which is secured to the side of the support plate between the two sprockets. A chamber containing pressurized grease is disposed in engagement with the movable abutment to vary the position thereof to vary the force of the spring acting on the idler sprocket to in turn vary the tension of the endless track. A plurality of guide rollers are rotatably mounted in engagement with the endless track on the same side of the support member as the sprockets.

Abstract: A tensioner with a pulley rotatably mounted onto a pivot arm where movement of the pivot arm is biased with a compression spring and movement is inhibited with a damping device. The compression spring is articulately mounted in such a manner that the torque output measured at the pivot arm may be substantially constant if so desired.

Abstract: A simplified, low cost and nonresonant belt or chain tensioner comprising a casing made of sheet metal, a compression spring and a subordinative compression spring of nonlinear characteristic.

Abstract: A belt or chain tensioner whereby a resonance due to chain or belt vibration is alleviated by means of hysteresis loss obtained by friction between adjacent elements of a reversely and closely wound multiple compression spring which urges a tension rod.

Abstract: A belt or chain tensioner provided with a detachable holder for locking an urging tension rod during storage and transport and a slipproof cap provided on the end of the tension rod for abutting against the holder.

Abstract: A chain tensioner comprises a body which is received in a bore formed through a side wall of a chain case, and includes a generally cylindrical portion. A plunger is slidably received in the cylindrical portion so as to press a timing chain. A check valve is arranged in the body. A damping chamber is defined by the cylindrical portion and the plunger, and is fluidly communicated with an oil pump via an oil supply passage. On the other hand, an oil reservoir is defined by the bore and the body, and is fluidly communicated with the damping chamber through the check valve via an oil passage, and also with the damping chamber via a flow restrictor.

Abstract: A belt or chain tensioner includes a collar mounted between a bearing and a spring seat. The spring seat includes a externally mounted on a cylinder portion of a rotational cylinder so as to prevent movement of the rotational cylinder in an axial direction and penetration of a torsion spring into a ring groove provided between the cylinder portion and a male threaded portion of the rotational cylinder.