Abstract: A hydraulic chain tensioner comprises a hollow plunger slidably received within the bore of a housing. A spring pushes the plunger in the protruding direction, and a pressure relief valve assembly and an air vent disc that are integrally incorporated on the upper end at the tip of the plunger. The air vent disc has a disc shape including a first and second face. An outer periphery is formed with a through-hole. The outer diameter of the air vent disc is slightly smaller than the inner diameter of the plunger. The first face is formed with a spiral groove and the circumferential edge portion of the first face is formed with a radius. The starting end of groove is disposed at the radius and the terminal end of the groove is centrally located on the first face.

Abstract: A ratchet-operated tensioner 1 is constituted by a principal plunger 4 slidably fitted into a cylinder chamber 3 formed in a tensioner body, an inner plunger 5 slidably fitted into the principal plunger, a compression spring 7 provided in an oil pressure chamber 6 and a ratchet mechanism 9. An O-ring 8 that slidably comes into contact with an inner wall of the principal plunger 4 is attached to an outer periphery of the inner plunger 5. In the ratchet-operated tensioner 1 with the pressure oil chamber according to the present invention the oil leak from the pressure oil chamber is prevented by preventing the oil leak from a gap between the principal plunger 4 and the inner plunger 7 during the engine's shutdown.

Abstract: A low cost hydraulic tensioner of die-casting metal or synthetic resin with a separate metallic cylinder free from dropping out of the cylinder and fine surface finishing, is provided. The tensioner 1 comprises a metallic cylinder 4 fitted to a cylindrical hole 3 formed in a body 2, a plunger 5 energized by a spring 7 and a pressure oil chamber 8 formed between the inner part of plunger 5 and the cylinder 4. The cylinder 4 is provided with a bottom plate 4B having a through hole 4A allowing the inflow of oil. The bottom plate 4B is prevented from dropping out from the body 2 by being engaged by the spring 7.

Abstract: In pressing a slack-side span of a V-ribbed belt, entrained about a crank pulley variable in rotational speed, auxiliary pulleys and an idler pulley, with an auto tensioner, thereby automatically balancing tension of the belt, the damping coefficient DI of the auto tensioner is set in accordance with the modulus of longitudinal elasticity of the belt. For example, when the modulus of longitudinal elasticity of the belt is at least 9800 N/100% rib and less than 29400 N/100% rib, the damping coefficient DI of the auto tensioner is set at at least 20% and less than 100%. In this manner, even if the rate at which the auto tensioner absorbs elongation of the belt is as extremely small as 0.3 to 1.0 mm/deg, a rocking motion of the auto tensioner can be avoided thereby reducing the occurrence of a slip or a frictional sound of the belt and the occurrence of abrasion and frictional sounds of friction members, such as an insert bearing and a thrust washer, of the auto tensioner.

Abstract: An autotensioner and a tension adjustor are provided with a detector for detecting the timing for belt replacement. The bottom end of a metal ring of an oil seal for closing a top opening of a cylinder is exposed. A guide flange slidable along the inner surface of the cylinder is mounted on a pushrod. Due to contact of the guide flange with the metal ring, the limit position of the forward stroke of the pushrod is detected and the belt replacement timing is notified.

Abstract: A hydraulic tensioner having in combination a pre-loaded biasing system for a secondary piston to reduce the operating loads in a drive chain or belt system at or near the maximum limit of the prescribed range for the tensioner and a pressure relief system to quickly and temporarily relieve hydraulic pressure when the operating loads exceed the maximum limit of the prescribed range. The pressure relief system is located at the juncture between a primary piston and the secondary piston and is opened when the secondary piston is forced to move independently of and toward the primary piston a predetermined stroke amount. Once the pressure relief system is opened, hydraulic fluid is discharged from the chamber to allow the tensioner to temporarily release tension on the chain or belt system. When the operating loads reduce below the maximum limit, the secondary piston moves to its normal operating range and the pressure relief system closes to allow the tension to return to its normal operating state.

Abstract: A hydraulic tensioner includes a relief valve mechanism assembled in a plunger and held in fluid communication with a high-pressure oil chamber defined between a housing and the plunger which is slidably inserted in a plunger accommodation bore in the housing with a tip portion projecting therefrom. The relief valve mechanism is composed of a cup-shaped orifice member having an orifice formed in an outer circumferential surface thereof, and a relief valve assembled in the cup-shaped orifice member. The relief valve includes a cup-shaped sleeve slidably received in the orifice member, a spring urging the sleeve toward the high-pressure chamber, and a discharge port normally closed by the sleeve and adapted to be opened when the sleeve is displaced against the force of the spring. The thus constructed relief valve mechanism is small in size and capable of achieving downsizing of the hydraulic tensioner.

Abstract: A plunger equipped with a relief valve mechanism is slidably mounted in a tensioner housing. The relief valve mechanism has a valve spring disposed between a valve and a spring retainer plug in a compressed condition. The spring retainer plug has a stopper surface formed on the side which opposes the valve. The maximum displacement of the valve and the maximum amount of compression of the valve spring are defined by the stopper surface so that the maximum shear stress acting in a wire of the valve spring is less than a fatigue limit of the valve spring wire.

Abstract: A belt transmission apparatus is capable of changing a set tension of an automatic belt tensioner 30 between a first optimal value suitable for engine starting and a second optimal value suitable for driving an accessory after an engine 1 has been started. The belt transmission apparatus includes a rotating electric machine pulley 8 of a rotating electric machine for transmitting starting power to the engine 1; an engine pulley 2 for transmitting the starting power to the engine 1 and also transmitting a rotation power of the engine 1 to accessories; auxiliary pulleys 3, 4, 5 being driven to rotate by the power from the engine pulley 2 thereby to drive the accessories, respectively; a belt 10 wrapped around the rotating electric machine pulley 8, the engine pulley 2 and the auxiliary pulleys 3, 4, 5 in succession; and a belt tension adjuster 9, 30 for urging the belt 10 so as to set a tension of the belt 10 in a plurality of stages.

Abstract: A chain drive is provided which includes a chain, a driven sprocket and a drive sprocket. A single portion of the chain is tensioned by two spring tensioners. The spring tensioners can act on a single side of the chain portion or on opposite sides of the chain portion.

Abstract: The invention is an improved belt drive system and method for a power plant. The power plant is of the type having a crankshaft pulley, an accessory pulley, a motor/generator pulley, a first belt tensioner, a first belt tensioner pulley, and a power transmission belt trained about the crankshaft pulley, the accessory pulley, the motor/generator pulley, and the first belt tensioner pulley. The power transmission belt has spans defined by terminations proximate to each of the pulleys. These spans include intermediate spans beginning at the crankshaft pulley and ending at the motor/generator pulley, following the direction of belt travel in normal operation. The intermediate spans include a first intermediate span having a crankshaft termination proximate the crankshaft pulley and a last intermediate span having a first motor/generator termination proximate the motor/generator pulley.

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: To provide a tensioner in which a bearing of the drive shaft of the conventional art is not necessary and also that enables the initial load of the torsion spring to be retained in an intact condition when the tensioner is disassembled for maintenance purposes or the like.

Abstract: A hydraulic tensioner having a piston slidably received in a housing bore and biased in a protruding direction by a spring. A pressure relief valve is positioned in the nose of the piston. The pressure relief valve includes a valve member and seat member. The valve member biased by a spring disposed between the seat member and a retaining plate on the valve member.

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 tensioner for a chain, includes a tensioner piston bearing upon a chain and guided by a cylinder for movement in the direction of the chain. The cylinder and the piston define a pressure chamber for receiving hydraulic fluid, wherein hydraulic fluid is able to escape from the pressure chamber via a leakage gap. A control member is provided to at least reduce the leakage gap in size, when a pressure in the pressure chamber increases.

Abstract: This tensioner comprises a casing, a first shaft member rotatably stored in the casing so as to be restrained from moving in its axial direction, a second shaft member in screwed engagement with the first shaft member, and a spring for applying a turning force to the first shaft member. The second shaft member is restrained from rotating relatively to the casing and allowed to move in the axial direction. An axial load from a force transmitting member, such as a chain or belt, acts on the first shaft member. An end face of the first shaft member touches a receiving surface of the casing across a washer. The end face receives the axial load that acts on the second shaft member. The flatness of at least the end face of the first shaft member is adjusted to 15 &mgr;m or less.

Abstract: A tensioner device having a tensioner and a lever urged by the tensioner into slide contact with a chain includes a plunger rotation inhibiting mechanism disposed between the front end portion of a plunger and a portion of the lever to inhibit the plunger from rotating about the axis thereof such that the front edge of each prong of a ratchet is kept separated from the bottom land of a mating one of rack teeth formed on an outer surface of the plunger along the axis thereof. The ratchet prong is substantially free from wear and has an improved degree of durability.

Abstract: A ratchet tensioner includes a plunger releasing mechanism for turning a ratchet pawl against the force of a plunger spring to disengage a locking prong of the ratchet pawl from a rack tooth of a plunger. The plunger releasing mechanism has a pin insertion hole formed in a plunger housing transversely across a recessed groove formed in the housing for mounting the ratchet pawl, and a sloped surface formed on the ratchet pawl and normally extending obliquely across the axis of the pin insertion hole. The sloped surface, upon abutment with the tip end of a pin which is inserted in the pin insertion hole, is capable of causing the ratchet pawl to turn against the force of the ratchet spring to thereby disengage the locking prong of the ratchet pawl from the rack tooth of the plunger for releasing the plunger.

Abstract: A chain tensioner, includes a housing intended for attachment to a stationary machine element of an internal combustion engine, and a piston received in the housing for axial displacement against a strand of a chain to thereby implement a tensioning of the chain. An adjusting mechanism is provided for moving the housing relative to the machine element in a direction to and away from the strand of the chain, whereby a spacer establishes a distance between the housing and the strand to thereby define an installation position of the housing.

Abstract: A hydraulic tensioner having a piston slidably fitted in a bore in a housing forming a fluid chamber. The piston is biased in a protruding direction by a spring and fluid. A check valve permits flow of fluid into the fluid chamber and prevents flow of fluid in the reverse direction. A pressure relief valve is provided in the fluid chamber. The pressure relief valve works with a vent disc having two separate vent paths. The pressure relief valve and vent disc provide controlled venting of fluid from the fluid chamber during both conventional operation and during periods of excessive pressure and thus, prevent collapse of the tensioner.

Abstract: A traveling screen system has a traveling screen guided about a multiplicity of support and guide rollers. A scanning device scans a transverse position of the traveling screen and an adjusting device adjusts the angular orientation of at least one of the support and guide rollers. The adjusting device is supported on one side on a displaceable bearing block which is supported on a carriage. Between the control device for the bearing block of the displaceable roller and the scanning device, a coupling is provided by which a return of the control motion of the roller to the scanning device is effected. The coupling is formed by a Bowden cable, by a hydraulic circuit with control cylinders, or by an electric circuit with control devices.

Abstract: A belt tension mechanism for tensioning an associated belt drive system on an associated vehicle is provided. The associated belt drive system includes a double stacked pulley, a first belt for providing power from a power mechanism to the double stacked pulley and a second belt for providing power from the double stacked pulley to an associated implement. A first tensioning mechanism is provided for tensioning the first belt and a second tensioning mechanism is provided for tensioning the second belt. A tension arm selectively simultaneously tensions the first and second belts from an inoperative condition to an operative condition or from an operative condition to an inoperative condition. A balancing mechanism is also provided for balancing tension on the first and second belts as the implement is selectively height adjusted.

Abstract: A tensioner, includes a hollow plunger guided in a cylinder for displacement in an axial direction and spring-loaded in a direction of a power transmitting element. A pressure chamber for receiving hydraulic fluid is defined by the cylinder and the plunger. Fitted interiorly of and being immobile with respect to the plunger is a control member which has a closed outer circumference, with a ring-shaped leakage gap formed by the plunger and the control member for passage of hydraulic fluid from the pressure chamber. The control member and the plunger have different coefficient of thermal expansion so that the leakage gap has dimensions which decrease as a temperature of the hydraulic fluid increases.

Abstract: A ratchet tensioner has a plunger retractably mounted in a housing and urged by a spring in a direction to project outward from the housing, and a ratchet pawl pivotally mounted on the housing and having a first prong normally engaged with one of ratchet teeth formed on the plunger so as to prevent backward motion of the plunger. The ratchet pawl also has a second prong spaced a predetermined distance from the first prong in the backward direction of the plunger and engageable with a second rack tooth to release meshing engagement between the first prong and the rack tooth when the plunger is moved forward due to a slack of a timing chain used with the tensioner. In order to maintain a predetermined amount of backlash between the first prong and the rack teeth, the rack teeth have a height greater than a half pitch of the ratchet teeth.

Abstract: A ratchet tensioner includes a mechanism for selectively locking and releasing a plunger with respect to a ratchet pawl. The plunger locking and releasing mechanism has an actuator plate secured to the shaft of a ratchet pawl body for co-rotation therewith above the outside surface of a housing shaft in which a pin-accommodating hole is formed. The actuator plate has a pin-insertion hole smaller in diameter than the pin-accommodating hole and is manually movable about the axis of the shaft in opposite directions between a locking position in which the pin-insertion hole is in substantial alignment with the pin-accommodating hole and the engagement between a ratchet pawl and ratchet teeth on the plunger is maintained, and a releasing position in which the pin-insertion hole is out of alignment with the pin-accommodating hole, and the ratchet pawl is released from interlocking engagement with the ratchet teeth against the force of a ratchet pawl spring.

Abstract: A ratchet tensioner includes a plunger locking and releasing mechanism for selectively locking and releasing a plunger relatively to a ratchet pawl pivotally mounted to a housing. The plunger locking and releasing mechanism has a lever-like pin contact portion formed integrally with a ratchet pawl body, a pin member-fitting hole formed in two opposed side walls of the housing in registry with the lever-like pin contact portion such that there being two pin-accommodating spaces defined between the lever-like pin contact portion and an inner peripheral surface of the pin member-fitting hole on opposite sides of the lever-like pin contact portion, and a pin member removably and selectively inserted in the pin-accommodating spaces.

Abstract: The tensioner comprises a cup fixed to an engine block and a pivot shaft which is fixed to a bolt engagement portion of the cup. The pivot shaft is inserted into a pivot bearing, and an arm is pivotally attached to the pivot shaft. The arm is biased by a torsion coil spring to rotate in a direction tensioning the belt. A sleeve having an axially extending slit is attached to an outer surface of the bolt engagement portion. One end of a coil spring is wound around the pivot bearing, and the other end is wound around the sleeve. The coil spring and the sleeve minutely deform by the rotation of the arm to generate a damping force. A damping force acting upon the arm when tensioning the belt is smaller than the damping force acting upon the arm when the belt is loosened.

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 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 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 chain tensioner assembly including a blade spring in interlocked association with a plastic shoe. The shoe includes slots at one end and a protruding portion and cylindrical hollow sleeve located at the other end to securely hold the blade spring thereagainst. The assembled shoe and blade spring is pivotally mounted to a bracket. The bracket has a tab with a notch in alignment with the hollow sleeve. A removable retaining pin engages the notch in the bracket and passes through the hollow sleeve to secure the tensioner to the bracket in a retracted state for shipping and subsequent application to an engine.

Abstract: The housing of a ratchet tensioner is formed of an aluminum-containing metallic material in order to decrease the weight of the tensioner. A hard alumite layer having a thickness of 5 to 50 &mgr;m is formed on the inner circumferential surface of a plunger accommodation bore formed in the housing, and a lubricant is incorporated into the alumite layer. Thus, the service life before occurrence of seizure is increased.

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: An auto tensioner comprises a fixing shaft having an arm supporting portion, an arm supported around the arm supporting portion of the fixing shaft so as to be swingable, for keeping the belt tension constant, a tension pulley supported rotatably at a free end of the arm, a friction pressing plate disposed so as to oppose the arm and blocked from rotating relative to the arm supporting portion, a friction plate disposed between the arm and the friction pressing plate so as to supply the arm with a swing resistance, and a twisting coil spring for pressing the arm against the friction plate so as to make the friction plate in contact with the friction pressing plate, wherein the friction pressing plate has a plurality of concave portions for collecting wearing particles generated because of a friction between the friction plate and friction pressing plate and wearing particles are collected in the concave portions so as to prevent the wearing particles from staying between the friction plate and friction pressi

Abstract: The drive-chain tensioner is automatically self-adjusting. A chain-slipper is guided to follow wear-movement of the chain. A cam is mounted on the follower. If slack in the chain increases, the cam is rotated by a cam spring to a position in which a larger radius of the cam lies under the follower. The cam provides a solid abutment that prevents the chain from compressing the tensioning springs and becoming slack when drive is reversed. For compactness and good load distribution, the chain is supported on a saddle between two cams. The cams have ratchet teeth.

Abstract: A chain or belt tensioner is provided in a header for a harvester having a pair of rollers, each supported on separate pivot arms and engagable with the slack and taut strands of the chain or belt. The pivot arms are mounted about a common pivot and are spring biased into engagement with the chain or belt by a common spring. When the drive direction is reversed, the normally slack side of the chain becomes taut and assumes a straight-line position between the sprockets or sheaves. The pivot arms will rotate about the pivot and the pivot arm on the strand that has now become slack will rotate to tension the slack strand. The biasing spring coupled to the two pivot arms biases the rollers against the two strands of the chain and provides a fixed tensioning force on the chain that does not require adjustment.

Abstract: A belt tensioner for a mechanical power transmission such as in a motor vehicle engine. The belt tensioner includes a wheel for bearing against the belt and a resilient return device for ensuring that the wheel bears against the belt with pre-stress. The wheel further includes a covering of vibration absorbing material. The invention is particularly applicable to mechanical engineering and specifically to the car industry.

Abstract: The present invention relates to a fabric raising machine including positively controlled raising/grinding cylinders, which comprises a plurality of rotary working cylinders, circumferentially arranged on a rotary framework, and for each working cylinder, a toothed pulley, thereon are entrained a cylinder closed loop driving toothed belt and cylinder closed loop timing belt to synchronize the operations of the toothed pulleys with the teeth of the driving belt.

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 hydraulic tensioner includes a plastic cap vent or check valve at the top of the piston. Oil and air that pass through the top end of the piston accumulate in the space between the plastic cap and the piston. The plastic cap moves small distances in the axial direction to permit the escape of air and oil through the plastic cap to atmosphere. A low rate spring may be used to cause the plastic cap to move away from the piston.

Abstract: A tensioning device is provided for drive belts, which is formed as a resilient, bendable ring. The ring is arranged to be inserted between lengths of the drive belt and may be positioned in a groove in one of the pulleys of the belt transmission of which the drive belt is an integral part. The ring is designed with such a large circumference that, during expansion, it is squeezed between the lengths of the drive belt, which causes the drive belt to be tensioned.

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 belt tension mechanism for tensioning an associated belt drive system on an associated vehicle is provided. The associated belt drive system includes a double stacked pulley, a first belt for providing power from a power mechanism to the double stacked pulley and a second belt for providing power from the double stacked pulley to an associated implement. A first tensioning mechanism is provided for tensioning the first belt and a second tensioning mechanism is provided for tensioning the second belt. A tension arm selectively simultaneously tensions the first and second belts from an inoperative condition to an operative condition or from an operative condition to an inoperative condition. A balancing mechanism is also provided for balancing tension on the first and second belts as the implement is selectively height adjusted.

Abstract: A hydraulic tensioner having an external rack member. The rack member has an extending member at its upper end that contacts wedges or grooves along the exterior of the piston to limit backdrive or backlash of the piston. The rack member has an end member at its lower end that is located in a groove in the tensioner housing. The rack member has a plurality of portions that are held together by a garter spring to form a single cylindrical piece.

Abstract: To reduce a sliding resistance of a tensioner lever of a transmission chain and to suppress any flapping vibration in a free span portion of the transmission chain, a tensioner lever (1,11) has a tensioner sprocket (2,12) disposed in registry with a bent portion of a transmission chain C having a minimum bent radius of curvature. The tensioner sprocket is pressed by the tensioner lever against the slack run of the transmission chain to form the bent portion, and a shoe member (3,13) is mounted between the tensioner sprocket and a proximal end (1', 11') of the tensioner lever to slidably guide the free span portion of the run.

Abstract: A chain tensioning system includes a pair of tensioners located one on each side of a driving sprocket, such as a crankshaft sprocket, between the driving sprocket and each of two driven sprockets, such as balance shaft sprockets. The dual tensioning system provides a tensioner to absorb torsional vibrations from the driving shaft in each of the two relative rotational directions of the driving shaft.

Abstract: An auto-tensioner that inhibits the generation of heat in an insert bearing made of a synthetic resin. An outer shell of an arm member is swingably supported on an inner shaft of a base member through an insert bearing made of a synthetic resin, and a tension pulley carried at a tip end of the arm member, is brought into pressure contact with an endless belt by biasing the arm member with a spring. By subjecting an inner surface of the outer shell in sliding contact with an outer peripheral surface of the insert bearing, to shot peening prior to assembly, the arithmetically averaged roughness Ra and the maximum height Ry of inner peripheral surface are regulated into ranges of1.times.10.sup.-6 m.ltoreq.Ra.ltoreq.10.times.10.sup.-6 mRy.ltoreq.60.times.10.sup.-6 m.

Abstract: A hydraulic tensioner device, which is compact in size, simple in construction and can be manufactured efficiently, has a shoe (4) for applying a tensioning force to a chain (3) or belt. The shoe has a plunger (5) which has a hollow portion (6) in which a valve block (7), a spring (9) and an inner sleeve (10) are slidably disposed. The upper end of the inner sleeve is supported within a cylindrical chamber (2) in a tensioner body (1). The tensioner body has an oil passage (11) communicating with an internal space of the inner sleeve. The bottom surface (6A) of the hollow portion and the valve block jointly define therebetween a high pressure chamber (8) filled with an oil supplied from the internal space of the inner sleeve via a check valve (7A) in the valve block.

Abstract: A belt tension adjusting device provided on a scanner transmission belt to adjust the tension of the transmission belt, includes a helical spring that helps maintain the tension of the transmission belt, a retaining post for fixing the position of the helical spring, and a toothed recess for connecting the scanner to the transmission belt.