Abstract: A belt take-up for a conveyor is provided with an internal compression spring to adjustably bias the bearing support tube to control tension on the conveyor belt. A scale on the bearing tube can provide a readout of the tension. A load cell can be employed to control a circuit to stop the conveyor motor when extreme high or low tensions of the belt are sensed.

Abstract: A tensioner is provided for a power transmission belt comprises a tensioning roller with which the belt cooperates, a return spring for controlling the displacement of said roller when the tension of the belt decreases and means for damping the vibrations likely to occur in the belt and comprising two variable volume chambers filled with a liquid and communicating together at one of their ends through a valve device through which the passage of the liquid entering and/or leaving said chambers introduces the damping effect, wherein the sidewall at least of one of the chambers is a membrane made from an elastomer material, such as rubber, having a general bell-shape and without spring, and the return spring associated with the other chamber is formed by a coil spring working under compression, prestressed in its rest state.

Abstract: A compact fluid actuated working cylinder is disclosed having a cam driven by a piston via a flexible tension member. At the ends of the cylinder housing there are deflection pulleys for providing continuous tension for the tension member. The pulleys are each mounted on pulley supports which extend from secondary bores in the main cylinder housing. The pulley supports are spring loaded and urge the two pulleys away from the cylinder housing and each other. The pulley supports are preferably rectangular in cross-section to protect against torsion.

Abstract: A tensioning device is provided for a flexible belt wound around the pulleys of a drive mechanism. The tensioning device includes an elastic biasing element and a damping mechanism. The biasing element applies a force on the belt in a predetermined direction to oppose belt slackenings. The damping mechanism dampens movements of the belt. The biasing element and the damping mechanism constitute a single unit wherein both exert on the belt forces which act on the belt at the same time in a predetermined direction to maintain a predetermined tensioning. The biasing element acts independently of the damping mechanism in the presence of considerable slackenings of the belt and functions as part of the damping mechanism to dampen thrusts of the belt acting on the device in the direction opposite to the predetermined direction. A connection unit connects the damping mechanism to the biasing element.

Abstract: In a tensioner in which a tension rod advances from the casing to apply a tension to a chain or timing belt, the advancement of the rod is locked by inserting a pin into a penetrated hole formed at the drawing out portion of the rod. The penetrated hole is sealed to prevent the loss of lubricating oil when the pin is removed.

Abstract: In a tensioner, a friction brake locks the advancement of a tension rod by a friction force provided and a tension rod advances from a casing by the pressurizing of the compression spring to maintain a belt, chain or the like in a suitable tension state. A coil portion is outwardly inserted through the tension rod in a closely contacted state and one end of the coil portion is latched to the casing, while another end forms a friction brake which is an operation end to cause an enlargement or the shrinkage of the diameter of the coil portion, by which the advancement and the removal of the tension rod is performed.

Abstract: A belt tensioning apparatus using a spring to provide the proper tension in a belt. A belt/pulley assembly is disclosed with one pulley slidably mounted on a bracket. A spring compressed to a fixed distance to provide a known force is attached to the bracket by a screw. The bracket, being initially free to move, transfers the force to the belt/pulley assembly for providing the optimum tension in the belt/pulley assembly. Once the proper tension in the belt is obtained, the bracket can be securely fixed, preventing movement between the pulleys in the assembly. Re-tensioning, when necessary, is accomplished easily by simply loosening and resecuring the bracket.

Abstract: A hydraulic actuating element particularly for a belt tightener having a pressure chamber arranged behind a piston guided in a cylinder, a reservoir separated from the pressure chamber by a check valve, the cylinder and the reservoir being completely oil filled, the outside of the reservoir being defined by a bellows, a leakage gap between the piston and the cylinder being open towards the reservoir and at its one side towards the pressure chamber, whereby a compression spring acts to urge apart the piston and cylinder, characterized in that the reservoir (13) surrounds the cylinder (2) and being limited by the bellows (12) at its outside, the bellows (12) being sealingly secured at one end to a base element (10) secured to the cylinder (2) and at its other end to a base element (11) secured to the piston (1), and that the leakage gap (3) at its other side (17) is externally shielded by the bellows (12) and open to the reservoir (13).

Abstract: A slack adjuster (500) is provided that is particularly advantageous for use in tensioning vehicular timing belts or chains. Adjuster (500) has substantially coaxially aligned status plunger (48), dynamic plunger (74), and sleeve (66). A first check valve (56) controls fluid flow between a first low pressure fluid reservoir or chamber (50) on plunger (48) and a second fluid chamber (84) in plunger (74). A second check valve (80) controls fluid flow between chamber (84) and a third fluid chamber in sleeve 66 includes a passageway (84) and also operates to prevent air from re-entering chamber (82) from passsageway (84).

Abstract: In a tensioner in which a male screw member and a female screw member are mounted in a casing of the tensioner in a screwed state and the female screw member advances in an axial direction by the rotation of the male screw member with the spring force, a cap is attached at the top end of the female screw member and further an oil sump storaging a lubricant oil is formed in an axial direction of the cap.

Abstract: The disclosure relates to a tensioning system for a drive belt (17). The system includes a tensioner (19) which is mounted to slide towards, and away from, the belt. An idler roller (22) is resiliently mounted in the tensioner (19) and is forced against the belt by means of springs, for example (84 and 85) in FIG. 8 or (102 and 103) in FIG. 9. The springs are arranged so that they increase the force applied by the roller to the belt as the tensioner is moved towards the belt until the force reaches a predetermined value, whereafter further movement over a limited range does ot further increase the force.The invension provides a tensioning system which will provide a predetermined lateral pressure on the belt without the necessity for using measuring apparatus during the adjustment of the static belt tension.

Abstract: A continuously variable transmission system having a fixed variable diameter pulley connected by a drive belt to at least one other pulley. A tensioner pulley maintains the tension on the drive belt within predetermined limits as the effective diameter of the variable diameter pulley changes. The effective diameter of the variable diameter pulley is determined by a balance between a resilient force biasing a plurality of belt engaging members in a predetermined direction and a radial force acting on the plurality of belt engaging members in the opposite direction. In a first embodiment, the resilient force biases the plurality of belt engaging members outwardly and the radial forces are generated by displacing the tensioner pulley to increase the tension on the drive belt. In an alternate embodiment, the plurality of belt engaging members are biased inwardly by a resilient force and are displaced outwardly by centrifugal forces.

Abstract: A tensioning device for chain or belt drives comprising a damping piston guided in a cylindrical housing and loaded in the chain tensioning direction by a compression spring located in the housing, wherein a high pressure chamber for hydraulic fluid is situated between the housing bottom and the damping piston and is open via a leakage gap formed by the guide bore of the housing and the damping piston and closed with respect to an oil reservoir by a non-return valve, the hydraulic pressure in the high pressure chamber during the operation of the tensioning device being higher in the cold state than in the heated state due to differences in viscosity, characterized in that the high pressure chamber is delimited by an additional piston acting as an overpressure piston on which a second compression spring acts in the direction of the high pressure chamber, the overpressure piston being able to bear against a fixed stop and the spring force of the second compression spring and the effective surface of the overpre

Abstract: In an electrophotographic system, a compact, space-efficient device is provided which allows adjustment and quick release of a photosensitive belt. An idler roller supporting the belt is used in conjunction with a cam which provides a take-up feature. A configuration is provided which allows the cam to be disengaged, and the idler roller retracted to facilitate removal of the belt.

Abstract: In a tensioner in which a tension rod advances from a casing to provide a tension to a chain or the like, the advancement of the tension rod is locked by inserting a pin into a hole formed in a portion where the rod is drawn out and further the drawn out portion of the tension rod is supported by a bearing portion formed at the bottom of the casing to stabilize the advancement of the rod.

Abstract: In a tensioner, in which a rotary body and an urged body are attached within a casing in a screwed portion and the urged body advances in an axial direction by the rotation of the rotary body with a spring force, a portion where an inner space of the casing and its outside interconnects is isolated with a selective transmission material which prevents oil penetration but allows air transmission.

Abstract: The invention is directed to a tensioning device for a portable handheld tool machine such as a grinding machine or cutting and grinding machine. Such machines have an arm which includes two component sections axially displaceable toward each other and between which a belt tensioning device is mounted. The displaceable component must be displaced against the force of the tensioning device toward the component fixed on the housing of the machine when mounting a new belt. This is inconvenient and leads to difficulties when mounting a new belt. A setting device is provided which acts upon the belt tensioning device. The setting device is movable between first and second positions and blocks the tensioning force in its first position and releases the tensioning force in its second position.

Abstract: An apparatus is proposed for tensioning V-belts, especially for automotive vehicles, said apparatus comprising a length-variable link member (6) for tensioning a pulley against the V-belt. The link member comprises a casing (10) carrying a connection bearing (9), and a piston rod (8) guided within the casing and carrying a further connection bearing (7), and a helical compression spring (18) fixed between a spring rest (19) of the casing and a spring rest (20) of the piston rod.

Abstract: An advancement and the advancing state of a tension rod which maintains a belt or a chain in a tension state is maintained by a coil spring. The coil spring deflects against an excess of opposite force from the belt or the chain to go back the tension rod and prevents the excess tension of the belt or the chain.The coil spring having a non-linear characteristic attached within the casing so as to be a range of the use including a changing point of a load deflection characteristic changes the number of active turns of the coil spring at the time of the resonance of the belt or the chain with changing point as the boarder.The above resonance decreases according to the change of the natural frequency of the vibration of the coil spring.The advancement of the tension rod can also be performed by the coil spring formed by the stranded wires.

Abstract: An automatic tensioning device for drive belts is equipped with a friction damper with low damping action against vibrations transmitted by the drive belt. A hydraulic shock damper has with high damping action is provided for large surge pulses. Preferably, the hydraulic shock damper an idle stroke in which the friction damper is active.

Abstract: The belt tensioning apparatus is comprised of a generally elongated housing having a first section and a second section. The second sections includes a lengthwise slot formed therein. A slide member having a roller rotatively mounted at one end and a tab formed at the other end is slidably mounted in the housing such that the slide member tab is located in said slot. A spring is mounted in the housing second section for applying a biasing force on the tab.

Abstract: A tensioner is provided with a female screw member for the tension adjustment of a belt or a chain screwed with a male screw provided a rotation force by a spring and a bearing in which the female screw member is inserted and constrains the rotation of the female screw member.In this tensioner, an outer form of the female screw member is formed so as to correspond to a bearing hole of the bearing. By this, an approximately whole length of the female screw member is able to slide through the bearing hole, and the stroke length of the female member can be secured sufficiently even if the size of the device in a tension controlling direction is shortened.

Abstract: A tensioner is provided for a power transmission belt comprising at least one return spring associated with the shaft of a tensioning roller with which the belt cooperates for controlling the displacement of said roller under the action of said spring, and two variable volume chambers each defined by an elastomer sheath, filled with a liquid and communicating with each other at one of their ends through a valve device through which the liquid flows into or out of said chambers and which introduces a damping effect of the vibrations likely to occur in the belt, wherein said sheath and a first spring portion associated with one of the chambers are fast with each other, by enveloping said first spring portion in said sheath, and said sheath and said second spring portion associated with the other chamber are independent of each other, said second spring portion surrounding the sheath and working under extension.

Abstract: An autotensioner includes a cylinder having its bottom closed and filled with a hydraulic oil and air, an oil seal mounted in the cylinder to seal the hydraulic oil and air, a rod slidably extending through the oil seal, and a piston slidably mounted in the cylinder with its top end abutting the bottom of the rod. The interior of the cylinder is separated into an upper reservoir chamber and a lower pressure chamber by the piston. Both chambers communicate with each other through a channel formed in the piston. The rod is biased by a spring mounted in the reservoir chamber in such a direction as to protrude from the cylinder. A check valve is provided in the pressure chamber near the bottom of the piston to open the channel in the piston only when the pressure in the pressure chamber is lower than the pressure in the reservoir chamber. The cylinder may have an outer casing and an inner sleeve so that the piston can slide on the inner surface of the sleeve.

Abstract: An autotensioner for adjusting the tension of a timing belt used with an automotive engine. It includes a cylinder case filled with a hydraulic oil, a piston partitioning the interior of the cylinder case into a pressure chamber and a reservoir chamber and a push rod having its bottom end coupled to the piston and the top end adapted to protrude from the cylinder case. A spring is provided to bias the piston and the push rod upwardly. The pressure chamber communicates with the reservoir chamber through a channel formed through the piston. A plate-shaped check valve is provided in the pressure chamber to open and close the bottom of the channel. The plate-shaped valve can respond quickly to the fluctuation of pressure in the pressure chamber because of its reduced mass.

Abstract: A tensioner device is provided with a rotary body energized the rotation by a spring and an urged body restricted the rotation by a bearing are inserted into a casing in a screwed state.The inner part of the casing is tightly closed by being covered with a bellows between the above casing and the urged body, and the torque of the rotary body is converted into a propelling force in a rod direction.In this case, an excess in pressurized air which compensates the change of an inner pressure caused by propelling of the urged body, is sealed within the casing.

Abstract: For preventing very small amplitude vibrations of the rod in a tensioner during high speed movement of a belt to be tensioned by the tensioner, a tube which is connected to a plunger which moves together with the rod is overlapped with a stationary member so as to define an annular clearance therebetween in an operating chamber of the tensioner. By filling an operating fluid in the clearance, shear strain is generated upon high speed movement of the plunger, which resists movement of the plunger.

Abstract: A hydraulically damped tensioner for a belt transmission system. A piston slidable with clearance in a cylinder form front and rear oil-filled chambers communicating through a passage in the piston with a check valve for restricting flow from the rear chamber to the front chamber. A piston rod is urged through the front chamber and against a roller by a spring in the rear chamber imparting tension on the belt. An opening, sealed by a removable plug, communicate with the front chamber to provide access for filling oil in both chambers.

Abstract: A tensioner is provided with a female screw member for the tension adjustment of a belt or a chain screwed with a male screw provided a rotation force by a spring and a bearing in which the female screw member is inserted and constrains the rotation of the female screw member.In this tensioner, an outer form of the female screw member is formed so as to correspond to a bearing hole of the bearing. By this, an approximately whole length of the female screw member is able to slide through the bearing hole, and the stroke length of the female member can be secured sufficiently even if the size of the device in a tension controlling direction is shortened.

Abstract: A resilient cage (100) is provided for retaining a check-valve (56) in registration with a passageway (54) through an end wall of the static plunger (48) for controlling fluid flow from a first fluid chamber (50) into a second fluid chamber (60). Static plunger (48) includes an annular groove (52) in its outer surface proximate the end wall and cage (100) includes a radially inwardly extending flange (6) that is adapted to extend into groove (52) and secure cage (100) in the manner of an end cap about the end of static plunger (48). Cage (100) also serves to retain static plunger (48) together with a dynamic plunger (28) containing chamber (60) against the force of a spring (64) tending to separate plungers (28 and 48) after assembly.

Abstract: A hydraulic ball-type check valve tensioner includes a plunger internally provided with an oil chamber and slidably fitted in a housing in association with a spring biasing the plunger in a protruding direction, and a ball-type check valve between the housing and oil chamber to permit oil flows into the oil chamber while blocking oil flow in the reverse direction. A relief valve includes a sleeve slidably fitted in an auxiliary oil chamber in communication with the oil chamber, a spring biasing the sleeve into a depressed position, and a discharge port to be opened when the sleeve is slided against the biasing spring action. A no-return mechanism includes a rack formed on the outer surface of the plunger, and a ratchet rotatably supported in the housing in meshing engagement with the rack and biased by a spring in a direction opposite to the protruding direction.

Abstract: A hydraulic ball-type check valve tensioner includes a plunger internally provided with an oil chamber and slidably fitted in a housing in association with a spring biasing the plunger in a protruding direction, and a ball-type check valve between the housing and oil chamber to permit oil flows into the oil chamber while blocking oil flow in the reverse direction. A relief valve includes a sleeve slidably fitted in an auxiliary oil chamber in communication with the oil chamber, a spring biasing the sleeve into a depressed position, and a discharge port to be opened when the sleeve is slided against the biasing spring action. A no-return mechanism includes a rack formed on the outer surface of the plunger, and a ratchet rotatably supported in the housing in meshing engagement with the rack and biased by a spring in a direction opposite to the protruding direction.

Abstract: An auto-tensioner for a belt has a cylindrical body having a bottom. A nut formed with female threads on its inner periphery and having a rod integrally formed at one end is slidably mounted in the body. A bolt is mounted in the body so that its male threads will engage the female threads on the nut. A belt loading spring is mounted between the nut and the bottom of the body to urge the nut in such a direction as to increase the tension to the belt. A bolt turning spring is mounted between the nut and the bolt to urge and turn the bolt in such a direction as to be pressed against the bottom of the body or in a direction away from the nut. Thus the nut and the bolt are moved either toward or away from each other according to the load from the belt which acts on the rod so as to automatically adjust the tension to the belt.

Abstract: Variable speed operation for the accessories of a prime mover (such as an engine) is obtained by a flat belt coupling a variable diameter flat belt driving pulley to flat belt pulleys attached to each of the accessories. The variable diameter pulley assembly includes a shaft and a pair of pulley sheaves each having a pair of relatively movable guideway disks lying alongside each other. Inner and outer guideway disks of each pair include, respectively, first and second series of spiral guideways extending in opposite directions such that the guideway intersections locate bearing ends of a circumferential array of belt engaging elements extending between the pulley sheaves. Thus, mutual angular change between the guideway disks causes corresponding change in the effective diameter of the pulley assembly.

Abstract: The hydraulic tightener includes a body defining a cylindrical cavity, a piston slidably mounted in the cavity and a pressure-applying shoe for applying pressure against an endless connection such as a chain. Associated with the piston there is a high pressure chamber defined by part of the cavity and the piston, the high pressure chamber being connected to a source of hydraulic fluid under pressure through a check-valve. This high pressure chamber is fluidtight and has no orifice other than the orifice provided with the check-valve. The tightener also serves to lubricate the endless connection or chain by spraying the hydraulic fluid thereon.

Abstract: A device for tensioning the cords of curtains, blinds or the like comprises a housing 1 and cover 3 defining a chamber 2 in which is slidably mounted a carriage 8 which has a boss 9 on which is rotatably mounted a pulley 10 for the cord 11 and a wheel 13 around which is wound a constant torque spring 17 the other shaped end of which is secured in a correspondingly shaped slot 18 formed in the end wall of the housing. The device is fixed to a wall or joinery by a screw 7 passing through a universally bore toggle 6.

Abstract: A belt tensioner has a shaft having an external thread and rotatably mounted in a body, a torsion spring provided between the body and the shaft so as to urge the shaft in a rotational direction, and a cylindrical rod having an internal thread engaged with the external thread of the shaft. A lower end of the rod is projected from the body so as to be operatively connected to a tension pulley for a belt. The torsion spring and both the threads are arranged to project the rod by the rotation of the shaft urged by the torsion spring. The rod is secured to the body so as to be adjusted in angular disposition.

Abstract: A hydraulically operated chain or belt tensioner is provided which in a preferred embodiment (500) features a piston or dynamic plunger (56) slidably received within a bore (54) of a housing (52) that includes a fluid chamber (65) that is vented by at least one air vent (76) extending through housing (52) that is oriented relative bore (54) such that tensioner (500) can be rotated a predetermined angular amount alpha relative horizontal with vent (76) maintaining a slope (B) greater than zero enabling entrapped air to escape from chamber (64) and preventing a substantial amount of fluid to drain therefrom by gravity when unpressurized.

Abstract: A self-contained type automatic belt tensioner adjusts a tension of an engine timing belt for automobiles. The tensioner comprises a body, a plunger slidably mounted in the body, a reservoir chamber located in the plunger, a pressure chamber disposed between the plunger and a closed wall of the body, a rod member fixed to the plunger, a bellows shaped elastic diaphragm located in the reservoir chamber with one end thereof being fixed to the rod member and the other end being fixed to the body, a check valve allowing a fluid flow only from the reservoir chamber to the pressure chamber, and a return spring interposed between the plunger and the closed wall of the body so as to bias said plunger in the direction of the rod member.

Abstract: A chain tightener with a dampening piston guided in a housing and axially acted upon by a spring in the chain tightening direction, and a radially resilient stop ring which cooperates with recesses of the housing and the dampening piston and limits its stroke while allowing a return movement of the dampening direction opposite to the chain tightening direction, wherein the housing (1) has a receiving groove (10) and the dampening piston (3) has an insert edge (25) for the stop ring (26) wherein during sliding of the dampening piston (3) into the housing (1) the insert edge (25) shifts the stop ring (26) until the latter radially snaps into the receiving groove (10), that a locking groove (18) for the stop ring (26) is provided at the dampening piston (3) which is defined on the one hand by a stop end face (19) and on the other hand by a stop ramp (20) wherein the stop ramp (20) fits under the stop ring (26) snapped in the receiving groove (10), that the stop end face (19) shifts the stop ring (26) under the a

Abstract: A free piston type auto-tensioner adjusts a tension of an engine timing belt for automobiles. The auto-tensioner includes a body, a plunger slidably disposed in the body to form a first oil chamber, a free piston slidably disposed in the body to form a second oil chamber, a first seal member disposed between the body and the piston, a second seal member disposed between the piston and a rod of the plunger, an oil passage formed in the plunger to establish an oil communication between the first and second oil chambers, a check valve disposed in the oil passage, a first spring biasing the plunger, and a second spring biasing the piston.

Abstract: A mechanical-hydraulic actuating element for a belt tightener especially for internal combustion engines comprising a piston (11) guided in a cylinder (10) between which a spring (14) acts so that piston (11) and cylinder (10) are urged apart wherein a pressure space (19) as defined by piston (11) and cylinder (10) is separated from an oil reservoir (16) by a check valve (20) which allows the free oil passsage from the oil reservoir (16) into the pressure space (19) while the annular gap between piston (11) and cylinder (10) is dimensioned so that oil can flow under pressure which counteracts the force of the spring (14) from the pressure space (19) into the oil reservoir (16) through the annular gap, characterized in that the oil reservoir (16) is designed as a circular ring-shaped hollow space which surrounds the cylinder (10) and is defined toward the outside by a hollow cylindrical cup-shaped housing (15) which is sealed at its open end by an elastic bellows seal (29) attached to the housing (15), on the

Abstract: A tensioner is provided for a power transmission belt comprising a return spring associated with the axis of a tensioner roller co-operating with the belt to control the displacement of said roller under the action of said spring with hydraulic type means for the dampening of vibrations generated in the belt. The spring is covered with an elastomer forming a sleeve closed at one of its ends by an obturator for defining said hydraulic dampening means which comprise at least one variable volume chamber filled with a liquid and closed at one of its extremities by a dissymmetrical valve device.

Abstract: In a chain tightener with a dampening piston guided in a housing and axially acted upon by a spring in the chain tightening direction wherein the dampening piston is retainable by a mounting ring within the housing in a blocking position which is released through axial pressure in the direction opposite to the chain tightening direction, the inprovement comprising the mounting ring (30) snaps into a groove (29) which is located at the forward end of the dampening piston (3) and is provided with a bevelled surface (28) and an adjacent latch surface (27), and that the mounting ring (30) is shiftable onto the latch surface (27) via the bevelled surface (28) with a tool insertable in a gap (31) between the housing (1) and the dampening piston (3) wherein the mounting ring (30) engages in a notch (13) of the housing (1) thereby blocking a movement of the dampening piston (3) relative to the housing (1).

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

Abstract: A chain tensioning device for chain and belt drives, comprising a tensioning head resiliently connected to a base and provided with a non-return device, wherein at least one pneumatic spring extends between the base and the tensioning head.

Abstract: A tensioning arrangement for a drive belt includes a support, a tension roller rotatably mounted on one end of the support, a swivel bearing arranged on the support at a distance from the tension roller, a swivel-damping element in the form of a linear-acting frictional damper having a master piston and a slave piston arranged in and separately frictionally engaging a cylinder, a spring arranged concentrically around the cylinder and coupled to the master piston, and a spring arranged inside the cylinder and coupled to the slave piston. The displacement of the master piston in one direction is opposed by the frictional forces separately acting on both pistons, whereas the displacement of the master piston in the other direction is opposed by the frictional forces acting on only the master piston.

Abstract: A belt tensioner has a shaft having an oil reservoir in a lower portion thereof and having an external thread and rotatably mounted in a body, a torsion spring provided between the body and the shaft so as to urge the shaft in a rotational direction, and a cylindrical rod having an internal thread engaged with the external thread of the shaft. A lower end of the rod being projected from the body so as to be operatively connected to a tension pulley for a belt. The torsion spring and both the threads are arranged to project rod by the rotation of the shaft urged by the torsion spring. An oil passage is provided in the shaft so as to communicate the oil reservoir with the bore above the internal thread of the rod.

Abstract: A belt or chain tension producing apparatus comprises a tension head engageable with a chain, belt or the like of a chain or belt drive and a tension piston on which the tension head is carried. The tension piston is guided longitudinally slidable in a guide body which is simultaneously a mounting element and is acted on by at least one tension spring engaged with it which is supported at its other end on the base of the guide body. In order to provide a particularly compact structure and thus also a more universal structure, at least a part of one side of the tension piston projects laterally from the guide body and the tension head is mounted laterally on a mounting surface on that projecting part. A recess may be provided in the tension head to better mount it on the tension piston.

Abstract: In a tension providing device having a rotary shaft which rotates the spring force in an inserted casing, a pushing body which slide in an axial direction by the aid of the rotation of the rotary shaft, a seal bolt screwed with the base end portion of the casing, and a boot which covers between casing and pushing body, the mixing of dust and foreign matters from outside and the leakage of the lubricant coated or filled in the inner portion are prevented due to the covering of the boot and seal with bolt.