In an aspect, a tensioner is provided for tensioning a belt on an engine, and includes a base mountable to a stationary member, and a first tensioner arm pivotably connected to the base. The first tensioner arm is biased in a first pivot direction. The tensioner includes a first bumper on one of the base and the first tensioner arm, which is engageable with a first travel limiter on the other of the base and the first tensioner arm to limit travel of the first tensioner arm in a second pivot direction, and a first pulley rotatably mounted to the first tensioner arm and positioned to engage a first section of the belt. The first bumper and the first travel limiter together have a selected first combined spring rate during engagement. The first combined spring rate increases progressively with compression between the first bumper and the first travel limiter.

Ring tensioners having a plurality of rungs that extend from a first side to an opposite second side of the ring tensioner, in use, the rungs engaging between the teeth of a toothed belt. Both the first side and the second side of the ring tensioner are not continuous but have gaps. The gaps on the first side alternate with the gaps on the second side. The ring tensioners may be formed from a single length of wire.

A crusher belt tensioning apparatus is arranged for being mounting on a crusher having a driven crusher pulley to actuate a crusher, a drive pulley drivable by a power unit, a belt extending between the crusher pulley and the drive pulley to transfer drive from the power unit to the crusher, and a tension drum mounted on a tension arm for applying a tension force to the belt. The tension arm includes a first relatively short arm portion and a second relatively long arm portion connected to the first relatively short arm portion. The tension drum is movable by a hydraulic cylinder, attached to the relatively short arm portion, between a first belt tensioning operating position in which the tension drum applies tension to the belt and a second belt non-tensioning maintenance position in which the belt is removable from the tensioning apparatus.

A chain tensioner (50; 500) for a conveying device (70) of a machine (1; 1) for processing elements in the form of sheets (10), the conveying device (70) includes two lateral chain sets connected to the ends of transverse gripper bars (75) able to grasp the elements (10) and at least one chain-guiding device (90) configured to guide a respective chain set (80); the chain tensioner (50; 500) includes: an actuator (9) controlled by a control unit (8), a movable support (11), a transmission element (12) borne by the movable support (11), a rotary element (13) rotated by the actuator (9) and cooperating with the transmission element (12) in order to exert a thrust force on the movable support (11), the rotary element (13) being rotatable, to adjust the tension of the chain set (80). The actuator (9) is controlled in synchronism with the machine angle (MA). A machine (1; 1) for processing elements and a method for tensioning the chain sets (80) of the conveying device (70) are disclosed.

To provide a chain tensioner capable of constantly providing an appropriate reaction force and damping characteristics for a variety of tension fluctuations irrespective of chain elongation, and capable of accommodating the tension fluctuations. The chain tensioner includes a distal end plunger 130 slidably inserted in a distal end bore 121 of a plunger 120, and a distal end biasing means 141 accommodated inside a second oil pressure chamber 102 such as to be able to expand and contract and to urge the distal end plunger 130. The chain tensioner further includes a check valve unit 150 that stops oil flowing from an oil pressure chamber 101 into the second oil pressure chamber 102, and a first relief valve unit 160 that releases oil toward the oil pressure chamber 101 when the pressure reaches or exceeds a predetermined high level.

A belt tensioner (1) for a belt drive for auxiliary units in an internal combustion engine, including a tensioner housing (2), a tensioner lever (3) and a plain bearing for radially mounting the tensioner lever (3) in the tensioner housing (2) in order to allow the tensioner lever (3) to pivot; a bearing partner associated with the tensioner lever (3) is in sliding contact with a second bearing partner associated with the tensioner housing (2). One of the two bearing partners is suspended in a radially elastic manner on the associated part that supports the bearing partner in a rotationally fixed manner.

A tensioner uses a low rate torsion spring in a first stage and a high rate torsion spring in a second stage to maintain tension in a chain or belt. The first stage is connected to the second stage by a torque coupling. The high rate torsion spring is maintained in an energized state between a ground and a dead stop to store energy and to provide tension under high loads. In some embodiments, the torque coupling is a damper. In other embodiments, the torque coupling is a clutch. A method stores energy in a high rate torsion spring of a tensioner.

Provided is a simple-structured tensioner that can reduce processing and assembling workload as well as increase the degree of design freedom. A tensioner 10 includes an oil supply hole 33 formed in a sleeve bottom 32 and a check valve 50 disposed on a front face of the sleeve bottom 32. The check valve 50 includes a check ball 51 and a retainer 52. The sleeve bottom 32 includes a ball seat 34 which protrudes in a cylindrical shape toward the front side integrally with and continuously from the edge of the oil supply hole 33 and on which the check ball 51 is seated.

A tensioner comprising a base having a base aperture, the base aperture disposed to receive a driven component, a rotary arm pivotally engaged with the base, an axis of rotation of the rotary arm aligned with a base aperture center, a first pulley journalled to the rotary arm, a swing arm pivotally engaged with the rotary arm about a shaft, the shaft and swing arm each having cooperating frustoconical portions, a torsion spring biasing the pivot arm, a second pulley journalled to the swing arm, a bushing having a frustoconical portion in frictional engagement with the swing arm frustoconical portion, the bushing in fixed relation to the shaft or pivot arm, and a first damping ring frictionally engaged between the rotary arm and the base, a Belleville spring in pressing engagement whereby a normal force is applied to the first damping ring.

The invention relates to a tensioning device for a traction drive, comprising a receiving housing, a roller carrier which is pivotably connected to the receiving housing, a helical tension spring which is supported at the receiving housing and at the roller carrier in circumferential and axial direction, wherein the roller carrier and the receiving housing are axially fixed relative to one another by the helical tension spring, a bearing arrangement by which the roller carrier is supported in the receiving housing so as to be rotatable around a rotational axis, a damping arrangement for damping a rotational movement of the roller carrier relative to the receiving housing, wherein the damping arrangement is arranged so as to be axially spaced from the bearing arrangement and is axially loaded by a tensile load of the helical tension spring.