Abstract: A combination starter-generator system for use in a vehicle is provided. The vehicle has an internal combustion engine and a battery. The system includes a starter-generator electrically coupled to the battery to generate a current and to start the internal combustion engine. A drive mechanism connects the starter-generator machine and the internal combustion engine. The starter-generator machine generates the current by receiving a charging torque from one side of the drive mechanism and starts the internal combustion engine by imparting a starting torque to a different side of the drive mechanism. The charging torque or the starting torque is a greater torque. A passive tensioning system cooperates with the drive mechanism to tension the drive mechanism only at the side of the greater torque.

Abstract: A traction device for an internal combustion engine includes a tensioning device having two lever arms of different lengths which are rigidly connected together and which are pivotally mounted for rotation about a rotation axis. Each of the lever arms supports on one end a tension pulley. The tensioning device is provided for positioning the tension pulleys on a pulling strand and a return strand by imposing an elastic force thereon.

Abstract: The invention comprises a belt drive cantilever tensioner. The tensioner is particularly suited to belt drive systems having a high belt tension. The tensioner comprises a pulley journaled to a cantilever arm. The cantilever arm is pivotably attached to a mounting surface by a fastener at a pivot. The cantilever arm further comprises a hole disposed radially from the pivot for containing an embedded resilient member. A second fastener extends through the resilient member fixing it in a position relative to the first fastener. A load applied to the pulley causes the arm to pivot thereby causing a lever action to exert a force upon the resilient member. The resilient member has a limit of movement as well as an asymmetric force characteristic which increases in proportion to an arm rotation.

Abstract: A tensioner having a base. A spring connected to the base biases a plate, having a pulley, toward a belt. Frictional blocks are aligned on the base in a staggered fashion along a spring centerline. The plate slidingly moves in a linear path between the blocks. The blocks constrain the path of the plate allowing movement in only a single axis parallel to a spring axis. A hubload from a belt running on the pulley combined with the spring force acting on the plate creates a force couple acting on the plate through the frictional blocks. The engaging surfaces between the plate and the blocks have a predetermined coefficient of friction thereby creating a damping force as the pulley and plate move in a linear path on the blocks.

Abstract: An idler assembly which is easily removable from a mower deck is disclosed. The idler assembly is rotatably mounted to the mower deck about a shouldered shaft and held in place by an easily removable spring clip. An idler pulley is rotatably attached to the other end of the idler arm. A spring is connected to a spring clip which is secured to the top of the idler arm. The spring causes the idler arm to rotate about the shouldered shaft and forces the idler pulley to apply tension to the drive belt. The idler arm also includes an extension which protrudes beyond the radius of the idler pulley to contact a snubber or bumper. The snubber is secured to the mower deck by a snubber bracket.

Abstract: A tensioner having a pulley journaled to a housing. The housing further comprises a guide. The guide slidingly engages rails on a base. The guide and rails constrain the housing to move in a predetermined linear path. The rails are horizontally offset from two axis defined by the pulley. The pulley load is also vertically offset from the axis of movement of the guide. The guide and rails have a predetermined frictional coefficient so that the cumulative result is an asymmetric damping effect. Further, a linkage is connected between the housing and a camming body. The camming body is rotatably connected to the base. A biasing member such as a torsion spring biases the camming body against the belt load through the linkage. The radius of the camming body is variable to maintain a constant belt load as the tensioner pulley moves in response to a load change.

Abstract: A drive belt stabilizer system for reducing non-longitudinal movement of a drive belt during operation. The drive belt stabilizer system includes a base, a lower member attached to the base, an upper member slidably positioned about the lower member in a vertical manner, a support stand attached to the upper member, a roller rotatably positioned within the support stand, a compression spring positioned within the lower member and the upper member for applying an expanding force relative thereto, and a securing shaft extending though the base and secured to the support stand for limiting the upward movement of the upper member. The roller is positioned beneath the return portion of a drive belt to be supported. A threaded nut is adjusted upon the securing shaft for adjusting the maximum height of the roller with respect to the drive belt.

Abstract: A drive belt tensioning method and assembly using a spring loaded, non-active tensioner. The spring is mounted between a base plate, and a tensioner arm, both of which rotate. A belt tensioning pulley is mounted on the tensioner arm, such that the belt tensioning pulley is adjacent to the drive belt. The tension of the spring causes the tensioner arm to rotate which causes the belt tensioning pulley to tension the drive belt. The spring chosen has a predetermined working length at which the drive belt has the desired tension. Because both the base plate and the tensioner arm rotate, the spring may be kept at this predetermined working length for each belt adjustment. This enables the drive belt to maintain the desired tension. An alignment index integral to the assembly may be used to ensure that the spring is at the predetermined working length.

Abstract: A belt apparatus is provided for use in a document processing system having a baseplate, a removable bearing assembly connected to the baseplate and having a drive pulley to which a drive belt is drivingly coupled. The belt apparatus comprises a bracket coupled to the baseplate and for supporting the drive belt when the bearing assembly including the drive pulley is removed from the baseplate. The bracket supports the drive belt below the baseplate to allow the drive belt and the drive pulley of a replacement bearing assembly to be easily coupled together without having to lift the baseplate to gain access to the space below the baseplate. Preferably, the bracket comprises a substantially U-shaped bracket. The bracket may include a pair of flanges on which the drive belt rests when the bearing assembly is removed from the baseplate. The pair of flanges extend in substantially opposite directions relative to each other and substantially parallel with the plane in which the baseplate lies.

Abstract: The invention comprises a self-contained mechanical belt tensioner that produces damping which is a function of the applied hubload through the effect of frictional forces derived from the sliding action of mutually opposing wedges. A first wedge or conical piston is contained within a housing. The conical piston cooperates with a second or conical wedge. A surface of the conical wedge slides on the inner surface of the housing. The conical wedge is expandable in a direction normal to the inner surface of the housing. A spring urges the conical wedge into engagement with the conical piston. As the pulley is loaded, as with an impulse load, the piston will move into the conical wedge. This, in turn, will cause the conical wedge to expand against the inner surface of the housing. The expansion of the conical wedge in the housing will increase the frictional force between the conical wedge and the housing. This will have the effect of damping movements of the conical piston and, in turn, of the pulley.

Abstract: The invention comprises a tensioner having a pulley journaled to a housing. The housing further comprises a guide. The guide slidingly engages rails on a base. The guide and rails constrain the housing to move in a predetermined linear path. The rails are horizontally offset from two axis defined by the pulley. The pulley load is also vertically offset from the axis of movement of the guide. The guide and rails have a predetermined frictional coefficient so that the cumulative result is an asymmetric damping effect. Further, a linkage is connected between the housing and a camming body. The camming body is rotatably connected to the base. A biasing member such as a torsion spring biases the camming body against the belt load through the linkage. The radius of the camming body is variable to maintain a constant belt load as the tensioner pulley moves in response to a load change.

Abstract: Use of the present invention enables the alignment and servicing of the rear derailleur of a bicycle without having the rear wheel or a specialized fixture mounted in the dropouts. For the present invention, the apparatus is placed on the frame of the bicycle and the chain routed over a toothed pulley. A tensioning spring in the apparatus provides the proper chain tension and allows the rear derailleur to be serviced or aligned.

Abstract: A continuously variable transmission has an endless V belt (15) running across a driving pulley (11) and a driven pulley (21), a transmission ratio changing mechanism for changing the running diameters of the belt around the pulleys radially in opposite directions to each other, and a tension-adjusting unit (50) for pressing the belt to obtain belt tension. The tension-adjusting unit (50) includes a tension roller (51) coming into pressure contact with the slack side of the belt (15) from outside, a swing arm (53) having an end rotatably supported on a transmission case (6), a link member (52) having an end rotatably supporting a shaft of the tension roller (51) and another end rotatably coupled with another end of the swing arm (53), and urging means (54, 55) for swingingly urging the swing arm (53) so that the tension roller (51) presses the belt (15).

Abstract: An autotensioner comprises a torsion coil spring interposed between a base and a rocking arm, and a tubular bushing provided between an inside surface of the base and an outside surface of the rocking arm. The torsion coil spring pushes and biases the rocking arm toward the bushing, and brings the pushing direction substantially in coincidence with the axial load direction of the force, acting on a stepped bolt supporting the rocking arm, from a belt. When the belt tension becomes high, the arm axial center displaces slightly from the base axial center, an extremely large first damping force acts on the rocking arm. When the belt tension becomes low, the smaller second damping force acts on the rocking arm.

Abstract: A tensioner comprises shaft members that mate with each other by way of thread portions. A first shaft member is rotatable with respect to a casing and is restrained from moving in its axial direction. A second shaft member, which is restrained from rotating with respect to the casing, is movable in its axial direction. A torsion spring applies torque in a first direction to the first shaft member. A torque switching member, which can switch frictional torque in association with the rotation of the first shaft member, is provided between the first shaft member and the casing.

Abstract: The invention comprises a tensioner having an inner race rotation idler pulley. The pulley having a web and a belt bearing surface connected to the web. The web is attached to an inner race of a bearing by a fastener. The pulley may be stamped out of sheet metal or of spun metal and may have a central hole for alignment with the central axis of the bearing. The outer race of the bearing is mounted to a pivot arm. The pivot arm comprises as least two pivot points for pivotably attaching the pivot arm to a mounting plate and a biasing member. The pivot points are contained within a periphery of the pulley. The biasing member urges the pivot arm and pulley against a belt to be tensioned.

Abstract: A combination starter-generator system for use in a vehicle is provided. The vehicle has an internal combustion engine and a battery. The system includes a starter-generator electrically coupled to the battery to generate a current and to start the internal combustion engine. A drive mechanism connects the starter-generator machine and the internal combustion engine. The starter-generator machine generates the current by receiving a charging torque from one side of the drive mechanism and starts the internal combustion engine by imparting a starting torque to a different side of the drive mechanism. The charging torque or the starting torque is a greater torque. A passive tensioning system cooperates with the drive mechanism to tension the drive mechanism only at the side of the greater torque.

Abstract: A tensioner has a substantially U-shaped stopper pin hooked at opposite end parts on a tensioner body and part of a plunger, respectively, to keep the plunger in a retracted position against the force of a spring before the tensioner is mounted to an engine body at an appropriate position relative to a power transmitting chain.

Abstract: A tensioner comprising a rigid cage provided with a fixing means for fixing to an engine block or to a plate rotatably mounted on the engine block. The cage slidably receives a rigid part that carries, preferably at one of its ends, bearing means for bearing against the belt, which bearing means can be constituted by a wheel. Resilient return means are mounted inside the wheel-supporting part to urge the cage and the part towards a spaced-apart position, the return means being constituted preferably by a helical spring.

Abstract: The invention is an improved tensioner for tensioning a power transmission belt. The tensioner is of the type having a track, a carrier mounted in sliding relation with the track with two degrees freedom of movement, a pulley rotatably mounted upon the carrier and for engaging the power transmission belt, a spring biasing the carrier in longitudinal relation to the track, and a damping mechanism that modifies the biasing of the spring based upon movement of the carrier in relation to the track. It is improved by the damping mechanism having a shoe placed in asymmetrical damping relation to the carrier and the track. Further, the shoe includes a first friction bearing surface in mating relationship with a second friction bearing surface of the track.

Abstract: The invention comprises a self-contained mechanical belt tensioner that produces damping which is a function of the applied hubload through the effect of frictional forces derived from the sliding action of mutually opposing wedges. A first wedge or conical piston is contained within a housing. The conical piston cooperates with a second or conical wedge. A surface of the conical wedge slides on the inner surface of the housing. The conical wedge is expandable in a direction normal to the inner surface of the housing. A spring urges the conical wedge into engagement with the conical piston. As the pulley is loaded, as with an impulse load, the piston will move into the conical wedge. This, in turn, will cause the conical wedge to expand against the inner surface of the housing. The expansion of the conical wedge in the housing will increase the frictional force between the conical wedge and the housing. This will have the effect of damping movements of the conical piston and, in turn, of the pulley.

Abstract: A drive belt tensioning method and assembly using a spring loaded, non-active tensioner. The spring is mounted between a base plate, and a tensioner arm, both of which rotate. A belt tensioning pulley is mounted on the tensioner arm, such that the belt tensioning pulley is adjacent to the drive belt. The tension of the spring causes the tensioner arm to rotate which causes the belt tensioning pulley to tension the drive belt. The spring chosen has a predetermined working length at which the drive belt has the desired tension. Because both the base plate and the tensioner arm rotate, the spring may be kept at this predetermined working length for each belt adjustment. This enables the drive belt to maintain the desired tension. An alignment index integral to the assembly may be used to ensure that the spring is at the predetermined working length.

Abstract: A closed hydraulic tensioner has a high-pressure chamber, a low-pressure chamber and a reservoir and contains an oil sealed in advance in the high-pressure chamber, the low-pressure chamber and the reservoir. The hydraulic tensioner further has an oil storage chamber disposed above the reservoir for holding therein an oil scattered within a chain case. The oil storage chamber communicates through an orifice with the reservoir. The hydraulic tensioner further has a bypass passage interconnecting the reservoir and the low-pressure chamber.

Abstract: A closed hydraulic tensioner has a high-pressure chamber, a low-pressure chamber and a reservoir that are previously filled with an oil sealed in the hydraulic tensioner. The hydraulic tensioner further has a pressure chamber disposed next to said reservoir with a movable member disposed therebetween so as to displace the movable member toward the reservoir to thereby pressurize the oil inside the reservoir. The pressure chamber is supplied with an oil from the exterior of the tensioner.

Abstract: A hydraulic tensioner includes a build-in relief valve having a relief hole formed in a housing of the tensioner, a ring-shaped valve element disposed in the housing at a side opposite to the front end of a plunger slidably mounted on the housing, and a spring urging the valve element in a direction to close the relief hole. The valve element and the spring of the relief valve are disposed coaxially with the plunger and a check valve provided between the housing and an oil chamber defined between the housing and the plunger. With this arrangement, the housing is made compact in size and hence enables downsizing of the tensioner. The relief valve disposed interiorly of the housing is highly reliable in operation.

Abstract: A hydraulic tensioner having a pawl-style rack member. The rack member is located in a groove in a bore in the tensioner housing. The tensioner piston has grooves along its exterior surface that correspond to the wedges or grooves in the pawl rack member and prevent the piston from being pushed inward. The pawl rack member may be a pair of pawls located in the tensioner bore. A flexible tab on the upper portion of the rack member contacts a groove on the upper portion of the piston to retain the piston in place for shipping.

Abstract: A hydraulic tensioning device for a power transmission system having a belt or a chain includes a cylinder and piston assembly of which a movable element, generally the piston, acts on the belt or chain so as to ensure that it is tensioned and thus ensures taking up of any slack in the chain or belt. The piston includes a plurality of piston elements slidable along a central axis of the cylinder.

Abstract: A tensioner for traction means such as a belt, includes a housing which accommodates a cylinder for guiding a hydraulically dampened, spring-loaded plunger in an axial direction for tensioning the traction means. The interior space of the housing is closed by a cover which has a guide opening for passage of the plunger. A seal is placed outside the cover to seal an annular opening bounded by the housing and the plunger. In order to prevent a gas cushion under pressure and trapped between the cover and the seal, from pushing the seal from its seat, the cover is formed with a vent passageway which communicates with the interior space for release of the gas cushion via the vent passageway into the interior space.

Abstract: A hydraulic tensioner having a hydraulically actuated rack member. A pair of check valves permit fluid to flow from an external source of pressurized fluid into a fluid chamber. The two check valves form a substantially fluid tight chamber in order to provide sufficient pressure to prevent the piston from retracting upon deenergization of the source of pressurized fluid.

Abstract: A tensioner for a driving member includes a piston (4) guided slidably in a housing (1) and spring-loaded against the driving member. The tensioner further includes a damping device (9, 18) for damping movements of the piston through discharge of hydraulic fluid, such as engine oil, from a pressure chamber (16) via at least one leak gap (13, 26) of the damping device (9, 18). A simple and economic implementation of the leak gap is assured by arranging a rotationally symmetrical body such as a cylinder (10) in a receptacle (11, 24) of the damping device (9, 18), so that the leak gap (13, 26) is formed between the wall (12, 25) of the receptacle and the peripheral surface of the rotationally symmetrical body (10).

Abstract: A device for tensioning flexible elements wound onto pulley has a pulley (4) onto which the flexible element (2) is (partially) wound is able to perform translatory movements relative and perpendicular to the shaft (8) on which it is rotatably mounted, respectively between an advanced position, where minimum tensioning of the flexible element (2) associated with the pulley (4) occurs, and a retracted position, where maximum tensioning of the flexible element (2) occurs, tensioning means being provided in order to cause said translatory movements of the pulley (4) with respect to the shaft (8).

Abstract: A transmission apparatus includes a chain operatively engaged with a driver sprocket assembly and a driven sprocket assembly, a tensioner bracket including a roller engaged with the chain, a tensioner rod including a plurality of spaced apart flange portions engageable with a brace and a threaded portion extending through an opening formed in the tensioner bracket and screwably attached to a plate. An operator may unscrew the tensioner rod and pass at least one of the flange portions through a slot in the brace to slacken the chain. The operator may also position at least one flange portion in a narrow end of the slot, and screw the tensioner rod to press that flange against the brace to tighten the chain.

Abstract: Disclosed is a tensioner for use in an engine. The tensioner comprises a fixed structure that fixes to the engine. A movable structure is mounted for movement relative to the fixed structure in a belt tensioning and opposite directions. A pulley member has a belt engaging surface that engages with the belt. One of the fixed and movable structures has an interior surface defining a fluid chamber containing fluid and the other includes a chamber dividing structure. The chamber dividing structure defines first and second chamber portions on opposing sides thereof. A biasing element biases the movable structure in the tensioning direction to tension the belt. Relative movement of the movable structure in the tensioning direction displaces fluid from the first to the second chamber portion and increases fluid pressure in the first chamber portion and decreases fluid pressure in the second chamber portion, and the reverse occurs during movement of the movable structure in the opposite direction.

Abstract: A tensioner, an engine fitted with such a tensioner, and a method of mounting such a tensioner. The linear tensioner having both a first end fixed to an engine without any degree of freedom, typically via a fixing endpiece having two parallel fixing openings, and also a second end opposite to the first end, and adapted for bearing against the belt, typically being constituted by a skid, a pulley, or preferably, a wheel. The first end and the second end are connected together by a resilient body, typically a coil spring, advantageously associated with a damper, typically hydraulic and/or elastomer, and also possibly adapted for guiding the two ends of the tensioner in relative translation. The present invention applies mainly to the automobile industry.

Abstract: A device for tensioning a traction mechanism, preferably a chain, which includes a traction wheel, preferably a sprocket (1), rotatably mounted on a hollow axle (3). Within the hollow axle (3), a hollow piston element (5, 6) is arranged, which is biased against the hollow axle (3) using a spring element, preferably a coil spring (12). The piston element (5, 6) is arranged in a piston chamber (4) such that the longitudinal axis of the piston element (5, 6) is arranged perpendicular to the traction wheel axis. In the inner space (7) of the piston element (6), motor oil is preferably provided for hydraulic damping of the piston element (6).

Abstract: A tensioner device for adjusting a tension in a chain wound around two sprockets includes a tensioner lever held in sliding contact with a slack run of the chain, an oil-filled tensioner provided on a stationary member, and a ratchet tensioner provided on the tensioner lever. The oil-filled tensioner includes a piston movable back and forth relatively to a housing attached to the stationary member, and a spring urging the piston in the forward direction. The ratchet tensioner includes a plunger movable in the forward direction relative to a housing formed integrally with the tensioner lever, and a spring urging the plunger in the forward direction. The piston and the plunger are held in face-to-face abutment with each other. The spring of the oil-filled tensioner has a larger spring coefficient than the spring of the ratchet tensioner.

Abstract: A tensioner guide includes a stationary shoe (6) having a contact surface (6A) confronting a free span of a transmission chain (4) between a pair of sprockets (2, 3), a movable shoe (7) movable relatively to the stationary shoe (6) in a direction toward and away from the transmission chain free span, and an urging member (9) for urging the movable shoe (7) toward the transmission chain free span. The movable shoe (7) has a contact surface (7A) being pressed against and in slide contact with the transmission chain free span by the action of the urging member (9) to hold a tension in the transmission chain (4).

Abstract: A hydraulic tensioner having a piston slidably received within a bore and biased outward by a spring. A check valve is fixedly mounted in the lower end of the piston. A low pressure fluid chamber is formed within the piston on one side of the check valve. A high pressure fluid chamber is formed on the other side of the check valve between the check valve and the bore. The spring is held within the piston by a reaction member.

Abstract: A hydraulic tensioner for a traction drive is provided having a spring-loaded piston (8) guided for longitudinal motion in a cylinder (6), in which tensioner, a piston motion causes an exchange of volume between a high pressure chamber (9) arranged in the cylinder (8) and a hollow space (4) which is partly filled with hydraulic medium, and, depending on a direction of motion of the piston (8), said exchange of volume can take place through a one-way valve (15), the tensioner further comprising a bellows seal (18) which is arranged between the piston (8) or the piston housing (10) at one end, and the outer housing (2) at a second end and follows the longitudinal motion of the piston (8) while bearing under pre-stress against the outer housing (2) and against the radially inward stepped piston housing (10).

Abstract: A chain tensioning arrangement arranged in a timing case for an internal-combustion engine which acts upon a timing chain that can be driven by the crankshaft of the internal-combustion engine. The chain tensioning arrangement provides a simple device with respect to assembly and operational reliability. The chain tensioning arrangement includes a tensioning member which can be adjusted between a mounting position, releasing chain tension and a tensioning position acting upon the chain. In the mounting position, the tensioning member is clamped by a releasable locking pin which extends beyond the floor of the timing case of the internal-combustion engine.

Abstract: A chain tension relieving device which prevents excessive tension being applied to a tension run of a chain. A shoe (5C) engages a tension run (3B) of a chain (3) stretched between a driving sprocket (1) and a driven sprocket (2) from another side of the chain in a bowed portion of the chain (3). When the tension acting on the tension run (3B) is of a prescribed value or less, the shoe surface of the shoe (5C) is held to a given advanced position so as to bow the tension run of the chain (3) by a biasing force of mechanical tensioner (15D). When the tension exceeds the prescribed value, the tension side (3B) of the chain (3) is straightened against the biasing force of the mechanical tensioner and the shoe surface of the shoe (5C) retreats from the given advanced position.

Abstract: A tensioner for traction elements such as belts and chains comprises a tension lever (2) on which is arranged a tension roller (3) for the traction element. A mounting lug (5) of the tension lever (2) is pivoted by a radial bearing (13) on an axle (6) provided on an engine block (4), while axial stops (8) are arranged on both ends of the mounting lug (5). The tensioner further comprises a tension spring element (1) which acts at one end on the tension lever (2) and at a second end on the engine block. To prevent rattling noises which result from axial displacements of the tension lever (2), the invention provides the arrangement of sealing rings (12) on the two axial ends of the mounting lug (5), which sealing rings (12) seal the radial bearing (13) at its front ends while projecting axially beyond the end surfaces of the mounting lug (5), the axial distance between the axial stops (8) being larger than the axial distance between the end surfaces of the sealing rings (12).

Abstract: A slide idler for a chain drive wherein the idler is provided with easily replaceable and rotatable bushings. The slide idler comprises two elongated members, each elongated member is provided with two inwardly extending polygonal mounting assemblies. Two cylindrical bushings having polygonal apertures corresponding to the polygonal mounting assemblies are mounted to these mounting assemblies and are sandwiched between the elongated members. A split pin is used to hold the slide idler together.

Abstract: A tensioner for belts and chains having a housing (1) in which a cylinder (3) containing a slidably guided piston (4) is arranged which piston (4) is supported radially by a guide bush (5), one end of a compression spring (13) engaging the piston (4), while the other end thereof engaging a cylinder base (6) of the cylinder (3), which cylinder base (6) is axially supported on a housing bottom (9) by a self-adjusting bearing (10) whereby, to improve the correction of alignment errors between the cylinder (3) and the piston (4), a plurality of peripherally adjacent raised portions (10) made of a ductile material are arranged between the housing bottom (9) and the cylinder base (6) and are plastically deformable under loading by the spring-loaded cylinder base (6).

Abstract: An autotensioner which can keep the tension in a belt at a constant level from the start of an engine. The autotensioner includes a cylinder having a top opening closed by an oil seal to prevent leakage of hydraulic oil in the cylinder. A rod slidably extends through the oil seal and is biased upward by a rod spring. At the bottom end of the rod is a hydraulic damper. A screw rod is slidably fitted on a small-diameter portion at the bottom end of the rod and is urged by a return spring against a shoulder formed on the rod. A nut member is axially immovably mounted in the cylinder while kept in mesh with a male thread formed on the screw rod. When the engine is cut, the belt may be stretched according to the positions of the cam on camshafts. If this happens, the rod is pushed inwardly by the belt. This rod pushing force is borne by pressure flanks of the threads at the thread engagement portions of the screw rod and the nut member to prevent the retraction of the rod.

Abstract: A mechanical friction tensioner for power transmission chains, such as engine timing chains. The tensioner provides the advantages of a conventional hydraulic tensioner, but eliminates the hydraulic pressure system by use of spring loaded wedge-shaped blocks and friction damping. The mechanical tensioner has a wedge-shaped plunger positioned within a bore in the tensioner housing. The plunger is biased outward by two spring loaded wedge-shaped blocks and a return spring. As the plunger moves inward, the wedge-shaped blocks are pushed in towards the plunger by the springs to provide friction damping.

Abstract: The variable tension pulley system including a drive pulley, a slave pulley, a belt interconnecting the drive pulley and slave, a tensioner assembly positioned between the drive pulley and the slave pulley and in engagement with the belt. The tensioner assembly includes an elongated rack, a drive rod rotatably positioned on the rack, the drive rod having opposing ends and being selectively rotatable in a positive rotation or a negative rotation.

Abstract: A tensioner with a base, a pivot-arm that oscillates about a pivot secured to the base, a pulley attached to the pivot-arm, a compression spring with a first end operatively connected to the pivot-arm and a second end operatively connected to a shoe that presses a convex surface of the shoe against a concave arcuate surface of the pivot-arm, and a second pivot-arm secured to the shoe and a second pivot secured to the base.

Abstract: A hydraulic tensioner having an air vent channel formed within or on its housing is provided. Air that mixes into the fluid chamber discharges from the fluid chamber in the bore to an external attachment surface of the housing. The air vent has a circuitous path from the inner wall surface to the external attachment surface, wherein the air vent has cross-sectional area substantially less than the cross-sectional area for the passage to the fluid chamber.

Abstract: A chain tensioner including a housing having a cylinder chamber, a rod member in the form of a threaded shaft inserted in the cylinder chamber for tensioning a chain, a tension adjusting spring for biasing the rod member outwardly of the housing, a hydraulic damper for damping axial dynamic load applied to the rod member from the chain by utilizing as a damping medium a hydraulic oil supplied into a closed end of the cylinder chamber through an oil supply passage formed in the housing and a check valve, and a thread engagement arrangement for preventing the rod member from retracting under an axial static load applied to the rod member. The chain tensioner can prevent the entry of air in the pressure chamber of the hydraulic damper when the engine is started in a cold environment or restarted.