Abstract: To provide a hydraulic tensioner lifter which can reduce the filling time of oil pressure into an oil chamber which is in a state wherein air is present therein and can sufficiently exhibit a vibration-damping function. A hydraulic tensioner lifter for applying tension to an endless power transmission band of a power transmission mechanism includes a plunger fitted for sliding movement in an accommodation hole of a tensioner body B and cooperating with the tensioner body B to define an oil chamber therebetween. An air-bleeder mechanism is provided for exhausting air in the oil chamber to the outside of the oil chamber. The purge valve P has a check valve function of permitting the exhaustion of the air in the oil chamber to the outside of the oil chamber but blocking admission of air into the oil chamber from the outside of the oil chamber and blocking discharging of the oil pressure in the oil chamber to the outside of the oil chamber.

Abstract: A cartridge tensioner (10) for drive transmission belts and chains comprises a cylinder (12) with a cylinder bore, a piston (14) slidably received in the cylinder bore and provided with a piston bore (40), a vent device (16) housed in the piston bore and comprising an end part and a stem integral with each other, a pressure spring (18) acting between a shoulder of the cylinder and the vent device, and a retaining device (20), accessible from the outside of the cylinder. The retaining device, in a position engaged with the stem of the vent device, retains the vent device preventing the action of the spring on the piston, and, in a position of disengagement from the stem of the vent device, allows the spring to bias the device against the piston and to act consequently on the piston.

Abstract: A chain tension-imparting device 100 comprises: a plunger 120, which retractably protrudes toward a traveling chain; a housing body 110 in which a plunger sliding hole 111 was formed; a protrusion biasing spring 130, which biases the plunger 120; a cam-receiving ring 140, which is displaced in an opening front end side diameter-increased concave portion 111a in the plunger sliding hole 111; a cam-receiving ring biasing spring 150 for biasing said the cam-receiving ring 140 in the protrusive direction of the plunger 120; a pair of wedge-shaped cam chips 160, 160, which slide on a sloped cam guide groove 141 formed on the cam-receiving ring 140 and engage with a plurality of racks 121, 121 engraved on the outer circumference of the plunger 120; a cam-guiding ring 170, for guide-controlling disengagement of the wedge-shaped cam chips 160; and a seal plate 180, which seals the opening front end side diameter-increased concave portion 111a.

Abstract: Chain tightener comprising a first supporting surface (11) on one branch (12) of the chain and a second supporting surface (13) on the other branch (14) of the chain with each supporting surface (11,13) being connected to a respective drive piston (19,119,20,120) into which is fed fluid for thrust in a tightening direction of the respective chain branch with the hydraulic circuits of the two pistons interconnected so that when one piston (19,119 or 20,120) is thrust in the direction opposite tightening from the tight branch of the chain it sends its fluid into the other piston (20,120 or 19,119) to thrust it to tighten the corresponding slack chain branch.

Abstract: A belt tensioning device for traction mechanisms includes a receiving and mounting housing, a pulley carrier pivotally connected to the receiving and mounting housing, a bearing supporting the pulley carrier relative to the receiving and mounting housing, and a spring located between the pulley carrier and the receiving and mounting housing for applying the tensioning force. The belt tensioning device, in normal operation, on the slack side between a generator and a main pulley can also be used when the slack side becomes the load side by a blocking mechanism which enables swinging motion of the pulley carrier relative to the receiving and mounting housing in a first direction, and limits or prevents such motion in a second, opposite direction.

Abstract: An asymmetric damping mechanism for use in a belt tensioner. The damping mechanism comprises two parts having substantially similar arcuate shapes for engaging a tensioner. The first part is in contact with the second part at a pivotable point of contact. The point of contact position is determined according to the desired asymmetric damping factor. The first part is also in contact with a spring. The second part is in contact with a tensioner arm. The damping mechanism also comprises two damping shoes, each having a damping band. The damping band is joined to the damping shoe by a plurality of vertical grooves on the damping shoe cooperating with a plurality of grooves on the damping band. The damping mechanism has an asymmetric damping factor in the range of approximately 1.5 to 5.

Abstract: To provide a hydraulic tensioner, which can prevent the bottoming out or over-stressing of a spring in an incorporated check valve, can reduce the contact surface pressure between a check ball and a retainer, and can reduce the production cost, a hydraulic tensioner comprises a check valve incorporated in the housing which causes oil to flow into a high pressure chamber to block the back flow of oil. The check valve comprises a ball seat, a check ball facing the ball seat, a spring, which biases the check ball against the ball seat and a retainer, which retains the spring and limits the movement of the check ball. The spring comprises a conical coil spring, and the surface of the retainer, which retains the conical coil spring and limits the movement of the check ball, is formed in a flat surface.

Abstract: A chain tensioner comprising a housing, a plunger having racks formed on its opposite sides, a protrusion biasing spring, cams arranged in oblique guide grooves in the housing and engageable with the racks of the plunger, and a spacer supporting a cam biasing spring. The minimum backlash distance X is equal to h/tan ?, where h is the height of the rack teeth, and ? is the angle of the cam guide surfaces relative to the protruding direction of the plunger. The angle ? is between 15° and 70°. The tensioner prevents wobbling noises produced by a timing chain on starting an engine, prevents whistling sounds due to excess tensioning of the chain, and allows backlash to be readily set to accommodate the requirements of a wide variety of engines.

Abstract: A plunger stop for temporarily holding the plunger of a ratchet type chain tensioner in place during installation of the tensioner, or during mounting or removal of the chain, comprises a bifurcated part inserted into a groove in which a pivoted ratchet pawl is situated. The bifurcated part is sandwiched between the pivoted ratchet pawl and a part of the tensioner housing, with the bifurcated part straddling a ratchet pawl-biasing spring in the groove. A grip, which is integral with the bifurcated part protrudes outside the tensioner housing so that it can be grasped manually for removal.

Abstract: A belt transmission apparatus capable of changing a tension of a belt by the action of belt tension adjuster 9, 30 from a first optimal value of higher tension suitable for the starting of engine 1 to a second optimal value of lower tension suitable for driving an accessory after 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 engine 1; engine pulley 2 for transmitting starting power to engine 1 and rotation power of engine 1 to accessories; auxiliary pulleys 3, 4, 5 rotated by the power from engine pulley 2 to drive the accessories belt 10 wrapped around rotating electric machine pulley 8, engine pulley 2 and auxiliary pulleys 3, 4, 5: and belt tension adjuster 9, 30 for urging belt 10 to set tension in a plurality of stages.

Abstract: The present invention comprises a hydraulic tensioner for applying tension to a chain without external fluid pressure supply. The hydraulic tensioner includes a piston assembly comprising a piston with a hollow interior and a piston bore surrounding the piston. An end of the piston assembly is submerged in fluid. An inlet check valve, which controls an entry of fluid into the piston, is located below the fluid level. An outlet check valve, located at an opposite end of the piston assembly from the inlet check valve, controls an exit of fluid from the piston. A non-return mechanism is coupled to the piston such that the piston extends but does not retract more than an included backlash amount. Utilizing the motion allowed within this backlash amount, the tensioner acts as a self-priming pump.

Abstract: A chain tensioner is provided, in which the design conditions of a register ring are optimized in compliance with the required functions so as to improve the durability, the operational stability and the like of the chain tensioner. A register ring is formed of a steel material having a tensile strength of 1000 to 3500 N/mm2. At the same time, an overlapping allowance of the register ring with respect to engagement grooves of a plunger is set within the range of 30 to 50% of a wire diameter of the register ring. Furthermore, a bending stress generated in the register ring when the register ring is made to slide between the engagement grooves to increase its diameter is set within the range of 500 to 1700 N/mm2.

Abstract: In a tensioner for a timing belt or chain in an engine, a plunger, which is spring-biased in a protruding direction, is temporarily held in a retracted condition by a pivoted U-shaped or L-shaped wire spring. The spring has a locking portion engageable with a pin or groove on the plunger, and two arms having ends remote from the locking portion. The ends are pivoted to the housing on laterally displaced pivot axes. The lateral displacement of the pivot axes causes the wire spring to be under stress when its locking portion is engaged with the plunger, and the stress urges the locking portion toward a disengaged position. Thus, the plunger is held in its retracted condition during assembly by the locking portion of the wire spring, but is automatically released by disengagement of the locking portion from the plunger when the plunger is moved farther in the retracting direction.

Abstract: A hydraulic automatic tensioner for adjusting the tension of a bell includes a first member with a piston formed integrally, a second member combined with the first member and axially movable relative to the first member, a cylinder formed integrally with the second member, together defining a fluid-reservoir chamber for hydraulic fluid, axially slidably receiving the piston, and a spring pushing the members apart. The piston and cylinder form a pressure chamber filled with hydraulic fluid. The second member has a leak passage through which fluid flows from the pressure chamber into the fluid-reservoir chamber. A control valve is placed in the leak passage, inhibiting flow of fluid from the pressure chamber into the fluid-reservoir chamber. A control device moves the control valve to close the leak passage when activated and makes it ineffective when deactivated so that the pressure chamber communicates with the fluid-reservoir chamber via the leak passage.

Abstract: A continuously variable transmission having an endless V belt running across a driving pulley and a driven pulley, 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 for pressing the belt to obtain belt tension. The tension-adjusting unit includes a tension roller coming into pressure contact with the slack side of the belt from outside, a swing arm having an end rotatably supported on a transmission case, a link member having an end rotatably supporting a shaft of the tension roller and another end rotatably coupled with another end of the swing arm, and an urging member for swingingly urging the swing arm so that the tension roller presses the belt. A linkage structure having two degrees of freedom is used for supporting the tension roller, so that the tension roller can automatically move to a position where it does not interfere with either pulley at any transmission ratio.

Abstract: A hydraulic tensioner that applies tension to a chain is comprised of a hollow plunger slidably received in a bore of the housing having an inner space defining a fluid chamber with the bore and a rack member provided slidably in an axial direction in a groove on the outer circumference of the plunger. The hydraulic tensioner further comprises a spring biasing the plunger in a protruding direction, a ratchet member provided slidably in a ratchet hole extending in an inclined direction intersecting an axis of the plunger having cylindrical head portion with an outer circumferential edge portion adapted to engage rack teeth of the rack member, permitting travel of the plunger in a protruding direction but preventing retraction of the plunger in a backward direction, and a coil spring that biases the ratchet member in an engaging direction of the rack teeth.

Abstract: In a ratchet-type hydraulic tensioner for use with a timing chain of an internal combustion engine, two or more oil reservoirs gradually receive oil fed under pressure from an external source, and supply the oil through a hydraulic valve mechanism to a high pressure oil chamber formed by a plunger and a housing in which the plunger is slidable. Throttle holes, formed in partition walls separating the reservoirs, control the flow of oil from one reservoir to another. An excess oil discharge hole is optionally provided in one of the reservoirs. The invention prevents abnormal protrusion of the plunger, reduces chain noise and component damage due to wear, and rapidly re-establishes proper tension on engine start-up.

Abstract: In a ratchet-type hydraulic tensioner for a chain transmission, having a plunger and a housing forming a high pressure oil chamber, an excess supply oil discharge passage is provided. The discharge passage communicates with an oil supply passage leading from an oil supply opening, which receives oil under pressure from a oil pump, to a hydraulic check valve mechanism in the housing, which delivers oil to the high pressure oil chamber. Excess oil is discharged to the exterior of the tensioner housing and directed toward the chain. Excessive chain tension is avoided, and smooth and reliable chain travel, and suppression of whistling sounds, are achieved.

Abstract: The invention relates to a tensioner (1) for a traction drive with a rotationally fixed housing (2) to a side of which a rotatable swivel arm (10), provided with a rotatable tension roller, is associated. A torsion spring (7) is placed between the housing (2) and the swivel arm (10) for loading the swivel arm (10) in the direction of an end position. Support of the tension spring (7) is realized by an insert (17a) placed in a circular ring shaped space (16) radially defined by a housing portion and the torsion spring (7).

Abstract: A hydraulic chain or belt tensioner includes a ratchet-pawl interface on the piston skirt that can be reset to a locked position by rotating the piston and compressing it until locked. The tensioner preferably includes at least one flat on the piston. The flat prevents the piston from rotating axially and locks the piston into place. The locked position is especially useful for shipping the tensioner.

Abstract: An engine chain or belt tensioning system includes a tensioner pivot arm with a ratcheting means that includes backlash in an engine timing system. The tensioner system includes a tensioner pivot arm having a fixed pin, ratchet teeth, and a connection for a rotation-causing device, all being spaced radially outward from a pivoting feature. The pivoting feature and the fixed pin are positioned between two strands of a chain. An arm carrying a shoe extended outside the strands of chain and positioned to contact an outside portion of chain is pivotally mounted to the fixed pin. Rotation of the pivot arm causes the arm and shoe to draw inwards, imparting tension to the chain strand. The ratchet teeth allow free rotation of the tensioner arm in one direction, but not the other.

Abstract: A plunger 4 and a spring 6 biasing the plunger 4 outwardly are mounted in a cylinder chamber 2 formed in a housing 1. The housing 1 is provided with an oil supply passage 8 communicating with a pressure chamber 7 formed in the back of the plunger 4. The housing 1 has an outer diameter that is substantially constant over the entire axial length, so that such housings can be mass-produced by pressing. It is thus possible to lower the cost of the chain tensioner.

Abstract: A belt tensioner (10) includes a housing part (12). The housing part (12) includes an elongated cylinder tube (18) in which a piston (14) is displaceably arranged. The belt tensioner (10) also includes a drive (16) which can exert a driving force onto the piston (14). The housing part (12) is constructed in a T-shape with a foot section (20) extending transversely away from the cylinder tube (18). The cylinder tube (18) is constructed in one piece with the cylinder tube and forms an accommodation space (30) for the drive (16). In a method for manufacturing such a belt tensioner (10), the foot section (20) forming the accommodation space (30) for the drive (16) is constructed in the housing part (12) by internal high pressure deformation.

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 belt driven starter motor system used to start an internal combustion engine. The system comprises a starter motor having a rotor and a pulley, a crankshaft pulley, and a belt tensioner, which are connected by a belt. The belt tensioner has a pulley that is movable between a first position and a second position. The tensioner pulley in the first position applies tension to the belt and the pulley in the second position corresponds to a condition wherein there is generally no tension on the belt. The starter motor begins rotation prior to the initial rotation of the crankshaft pulley, whereby the starter motor partially uses rotational energy to rotate the crankshaft pulley, which results in starting the internal combustion engine.

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: A check valve for a hydraulic chain tensioner comprising a substantially cylindrical body, a first ball, a second ball, and a spring. The cylindrical body has a first aperture at one end and a second aperture at an opposite end. The first aperture in the cylindrical body connects the hydraulic chain tensioner to a pressurized fluid source and the third aperture allows pressurized fluid to flow out of the hydraulic tensioner. The first ball is seated in a first aperture and the second ball is seated in a second aperture. The spring is located between the first and the second ball, biasing the first ball to seat and block fluid from returning from the hydraulic chain tensioner to the pressurized fluid source.

Abstract: A hydraulic tensioner includes a housing with a piston bore. A hollow piston with rack teeth on an outer circumference is inserted slidably in the piston bore, forming a fluid chamber. A piston spring urges the piston to extend. A retraction blocking member such as a pawl is provided in a retraction blocking member opening. The pawl has teeth engageable with the piston rack teeth, and a pawl spring that urges the teeth of the pawl member to engage the rack teeth. The width of the pawl member is greater than the width of the tip portion of the rack teeth of the piston. In one embodiment, a pawl retainer is mounted at a retainer hole and houses the pawl. In this embodiment, the width of the axial portion of the pawl retainer is greater than the width of the tip portion of the rack teeth of the piston.

Abstract: In ratchet type tensioner, low cost, high strength and excellent wear resistance, are realized by utilization of a pawl composed of a sintered alloy having a density of 6.8 g/cm3 or more, and containing 5-15 wt % Co, a total of 2.0-10 wt % of at least one metal from Ni, Cr and Mo, and the balance Fe and impurities.

Abstract: A hydraulic chain or belt tensioner includes a ratchet-pawl interface on the piston skirt that can be reset to a locked position by rotating the piston and compressing it until locked. The tensioner preferably includes at least one flat on the piston. The flat prevents the piston from rotating axially and locks the piston into place. The locked position is especially useful for shipping the tensioner.

Abstract: A hydraulic tensioner that decreases the number of components, secures an adequate backlash, and prevents backward movement of a plunger. The hydraulic tensioner includes a hollow plunger having rack teeth formed on a portion of an outer circumferential surface, slidably received in a bore of the housing, where the plunger has an inner space to form a fluid chamber with the bore. A slider housing portion, having an inclined surface, located in the housing, receives a wedge-shaped slider having a ratchet portion adapted to engage with the rack teeth of the plunger and a second side surface. The wedge-shaped slider being slidable along the inclined surface of the slider housing portion in a direction crossing an axial centerline of the plunger. The hydraulic tensioner further includes a first spring biasing the plunger in a protruding direction, and a second spring biasing the slider such that the slider moves along the inclined slide surface of the slider housing portion.

Abstract: A chain tensioner has a spring-biased plunger with rack teeth engageable with teeth of wedge-shaped cam chips cooperating with a spring-biased cam-receiving ring in a recess formed in a tensioner housing. A seal plate, having a central hole through which the plunger extends, is provided as a closure for the recess to hold the cam chip assembly in place. A wire loop, for temporarily engaging a pin protruding laterally from the plunger, is pivoted in tube formed by rolling a portion of a seal plate. The wire loop holds the plunger in its retracted state while the tensioner is being installed, and automatically disengages the laterally protruding pin when the plunger is pushed inward by a tensioner lever, thereby releasing the plunger for normal operation.

Abstract: An idler or tensioning assembly for an electronically controlled sanding/polishing machine is provided, the sanding/polishing machine utilizing a plurality of exchangeable polishing wheel assemblies of which the idler assembly is one. Each polishing wheel assembly interfaces with the sanding/polishing machine through a coolant manifold and a polishing wheel shaft receptor. The idler assembly is operative to provide releasable tension to a sanding/polishing belt that is situated around the idler and the associated sanding/polishing wheel. The idler assembly has a pivoting idler that is actuated by a hydraulic cylinder. The hydraulic cylinder utilizes coolant tapped from the coolant manifold of the idler assembly for actuation. Coolant is provided to the hydraulic cylinder in response to a valve signal. The idler assembly thus has a tensioned mode and an untensioned mode.

Abstract: The invention is directed to a tensioner assembly for providing tensile force from a floating vessel at the surface of the ocean to the blowout preventer stack, or production tree, which is connected to the wellhead at the sea floor. The tensioner assembly compensates for vessel motion induced by wave action and heave and maintains a variable tension to the riser string alleviating the potential for compression and thus buckling or failure of the riser string. The tensioner assembly of the present invention includes a cylinder, a stop tube disposed with the cylinder, and a ram slidably engaged within the stop tube. The tensioner assembly also includes at least one gas, or air, transfer tube to create a pressurized air over hydraulic fluid arrangement to provide tensile force to the tensioner assembly.

Abstract: In a ratchet type tensioner comprising a housing, a plunger slidable in, and protruding from, the housing, and biased in a protruding direction, a ratchet mechanism comprising a rack formed on a side surface of the plunger, and a pawl provided on the housing and engageable with the rack to prevent the return movement of the plunger, the pawl is composed of a sintered alloy having a density of at least 7.2 g/cm3. The sintered alloy is formed by warm molding, high temperature sintering, recompression, or combinations thereof, and preferably contains a total of 0.5 to 8 weight % of at least one element from the group consisting of Nickel, Copper and Molybdenum. The balance of the composition of the sintered alloy consists of Iron and impurities. The invention provides a ratchet type tensioner having a high strength and excellent wear resistance at a low cost.

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 present invention relates to a hydraulic type plastic tensioner comprising a body of the tensioner, which is made of plastics, a hollow metallic cylinder fit into a circular hole formed in the body, a plunger and a check valve mechanism. A ball seat in the check valve mechanism is provided on a bottom portion of the circular hole, and a retainer in a retainer-integrated type cylinder is press-fit onto the check ball to hold the cylinder in the circular hole.

Abstract: A piston rod position detecting mechanism is proposed which can detect continuously or in a multiple-point manner that the piston rod position has changed due to increase or decrease in the protruding amount of the piston rod due to aging. The protruding amount from a cylinder end wall is detected by a position detecting mechanism comprising a detecting coil housed in a bobbin provided at the cylinder end, a flange portion formed on the piston rod, and a coil spring. Also, an autotensioner and an electromagnetic valve with such a position detector are proposed. Further, a belt tension adjusting device is provided with a detector for detecting the position of a tension pulley which is pivotable with increase or decrease in the belt tension.

Abstract: A tensioner, in which an inner body and an outer body, which can deal with tensioner mounting forms and tension imparting functions required from various engines can be assembled and its efficient production and reliable assembling without wobbling and clattering can be performed. A body 22 of a tensioner 21 is composed of plastic outer and inner bodies 23 and 24 formed by different members respectively. The outer body 23 is provided with a tensioner mounting means and an inner body fitting hole 23a, the inner body is provided with a plunger accommodating hole 24a, a plunger 26 biased by a compression spring 27 is slidably fitted into the plunger accommodating hole 24a, a bottom portion of the plunger accommodating hole 24a is provided with a check valve 31, and at least the inner body 24, the check valve 31, the compression spring 27 and the plunger 26 form an inner body side unit 33, which imparts proper tension.

Abstract: A tensioner, in which an outer body and an inner body, which can deal with a tensioner mounting form required from various engines and a tension-imparting function, can be assembled, the inner body and a movement backward preventing mechanism, which form an inner body side unit, can be unitized in a shape by which press-fitting and assembling is easy, and its efficient assembling production can be performed. A body 22 of a tensioner 21 is composed of outer and inner bodies 23 and 24 of different members. The outer body 23 is provided with a tensioner mounting means and an inner body fitting hole 23a. The inner body 24 is provided with a plunger accommodating hole 24a into which a plunger 26 biased by a compression spring 27 was slidably fitted, and a movement backward preventing mechanism 32 for preventing the backward movement of the plunger 26 is incorporated into the inner body 24.

Abstract: In a belt tensioner, a cylinder is mounted to a side of a stationary member positioned in an upper side. A plunger is mounted to a side of a pulley positioned in a lower side. An outer tube sectioning an oil reservoir forming a gas chamber in an upper portion is provided in an outer periphery of the plunger and the cylinder. A first oil passage communicating the gas chamber with a high pressure oil chamber is provided in an upper portion of the cylinder. A second oil passage communicating the high pressure oil chamber with the oil reservoir is provided in the plunger. An orifice hole is provided in the first oil passage. A first check valve closing at an expansion time is provided in the first oil passage, and a second check valve closing at a compression time is provided in the second oil passage.

Abstract: It is desired to improve the wear resistance of the valve seat of the check valve in a hydraulic tensioner. The hydraulic tensioner includes a cylinder having a hollow space filled with hydraulic oil. A plunger is slidably mounted in the cylinder. A pushrod is mounted in the hollow space so as to be axially movable together with the plunger with one end thereof protruding from the cylinder. A spring is mounted in the cylinder to bias the plunger and pushrod outwardly of the cylinder. The plunger is formed with a passage through which the pressure chamber and the reservoir chamber communicate with each other. The passage is formed with a valve seat. A check ball is arranged so as to be moved into and out of contact with the valve seat. The check ball is adapted to contact the valve seat when the pressure in the pressure chamber exceeds the pressure in the reservoir chamber, thereby closing the passage. The valve seat is formed of a steel for carburizing and has a surface carbon concentration of 0.55-0.

Abstract: The present invention comprises a hydraulic tensioner for applying tension to a chain without external fluid pressure supply. The hydraulic tensioner includes a piston assembly comprising a piston with a hollow interior and a piston bore surrounding the piston. An end of the piston assembly is submerged in fluid. An inlet check valve, which controls an entry of fluid into the piston, is located below the fluid level. An outlet check valve, located at an opposite end of the piston assembly from the inlet check valve, controls an exit of fluid from the piston. A non-return mechanism is coupled to the piston such that the piston extends but does not retract more than an included backlash amount. Utilizing the motion allowed within this backlash amount, the tensioner acts as a self-priming pump.

Abstract: The present invention relates to a tensioner for endless driving elements, such as chains, belts etc., comprising a tensioning piston provided with locking means, and a locking piston which is implemented such that it is adapted to be engaged with and disengaged from said locking means so as to arrest or release the movement of said tensioning piston, said locking piston comprising an operating section causing said locking piston to move to the arresting position and to the release position, and a locking area used for engagement with said locking means of the tensioning piston and arranged separately from said operating section.

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 relieve hydraulic pressure when the operating loads exceed the maximum limit of the prescribed range. The pressure relief system 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: The invention provides for a guide system (10) for tensioning a belt. The guide system (10) comprises an endless belt (12); at least two guides (14, 16) for guiding the belt (12); and tensioning means (18) for tensioning the belt (12) between the guides (14, 16), the tensioning means (18) being movable between a tensioned and a substantially non-tensioned position such that in the tensioned position it is biased to the non-tensioned position to compensate for a loss in belt tension. The guide system (10) also comprises self-adjusting regulating means that is operatively associated with the tensioning means (18) and that is adapted for moving the tensioning means (18) towards its tensioned position upon occurrence of belt slacking for effecting substantially immediate tensioning of the belt (12) while the belt (12) is running and without the necessity of manual intervention.

Abstract: A drive unit of a carriage has a drive wheel and a deflector, offset parallel to a racks both of which are implemented as gearwheels, around which a closed elastic toothed belt with teeth on both sides is guided, whose inner teeth engage with the wheels described and whose outer teeth engage with the rack. A pressure block relocatable relative to the rack is positioned between the wheels, which exercises an elastic force on the part of the toothed belt facing the rack by means of a pressure surface under the influence of the part facing away from the rack, which presses the first part mentioned against the rack. In this way, a snug engagement with the rack and low-noise and uniform movement of the carriage are always ensured. A pressure wheel implemented as a pinion and engaging with the inner teeth of the toothed belt can also be used instead of the pressure block.

Abstract: A self-adjusting contact mechanism is provided for a belt drive system which mechanism includes a contact shoe having a low friction surface in contact with the belt and a mechanism for biasing the low friction surface of the contact shoe against the belt with a controlled force profile which may be constant or may vary within a selected range over the permitted movement for the shoe. The shoe is preferably mounted to a lever arm through a pivot joint to permit the shoe to remain substantially parallel to the belt and in contact with the belt over the entire low friction surface of the shoe regardless of lever arm position. Force on the lever arm is provided by a compression mechanism which may include a pair of counterbalancing springs, with the spring biasing the lever arm toward the belt being stronger than the counterbalancing spring and preferably with the force for at least one of the springs being adjustable.

Abstract: In a chain tensioner comprising a plunger having toothed racks engageable with wedge-shaped cams which cooperate with oblique cam-guiding surfaces, the cam-guiding surfaces are formed on a cam-receiving ring disposed in an enlarged part of the cam-receiving hole adjacent the front end of the tensioner housing, and axially movable, through a limited distance, in a space between a shoulder and a seal cap. The axially movable cam-receiving ring increases both the minimum and maximum backlash distances of the plunger, thereby making it possible for the tensioner to accommodate different chain conditions by changing the axial dimensions of the cam-receiving ring, or the space in which it moves, instead of, or in addition to, modifying the angle of the cam-guiding surfaces.

Abstract: A chain tensioner comprising a housing, a plunger having racks formed on its opposite sides, a protrusion biasing spring, cams arranged in oblique guide grooves in the housing and engageable with the racks of the plunger, and a spacer supporting a cam biasing spring. The minimum backlash distance X is equal to h/tan &thgr;, where h is the height of the rack teeth, and &thgr; is the angle of the cam guide surfaces relative to the protruding direction of the plunger. The angle &thgr; is between 15° and 70°. The tensioner prevents wobbling noises produced by a timing chain on starting an engine, prevents whistling sounds due to excess tensioning of the chain, and allows backlash to be readily set to accommodate the requirements of a wide variety of engines.