A drive arrangement is provided which includes: a first and second rotatable members; an endless loop member, extending around the first and second rotatable members, arranged to convey drive from the first rotatable member to the second rotatable member; a first support, arranged to support the first rotatable member and the second rotatable member, having at least one aperture therein; a guide member, defining at least part of a path of the endless loop member between the first rotatable member and the second rotatable member; and a second support, arranged to support the guide member, the second support being connected to the guide member through the at least one aperture in the first support such that guide member is movable, via the at least one aperture, to engage and disengage drive from the first rotatable member to the second rotatable member.

Provided is a chain tensioner that can always provide a suitable reaction force and damping force to various tension fluctuations of the chain, has a simple structure, is easy to produce, and also enables a reduction in the production cost. The chain tensioner 100 has a plunger 120 inserted in a plunger bore 111, and biasing means 140 for biasing the plunger in a protruding direction of the plunger. A plurality of biasing means 140 are accommodated so as to freely expand and contract inside a high pressure chamber 101 and arranged in series along the protruding direction of the plunger 120, with a separator plate 130 interposed therebetween. The separator plate 130 has one or more oil passages that adjust oil flow.

A linear tensioner is provided for tensioning a traction mechanism provided in a drive system with a first adjustment element that has a hollow-cylindrical construction and a second adjustment element that is guided so that it can be moved longitudinally on this first element, wherein contact surfaces are formed on facing end surfaces of the adjustment elements, on which a compression spring actuating at least one of the adjustment elements in the tensioning direction is supported. A transport securing device is provided that prevents, in a specified locked position, a movement of the adjustment elements relative to each other by at least one locking element.

An earth working machine (10), encompassing a drive motor (42) and a working apparatus (22) drivable by the drive motor (42) so as to move rotationally, the drive motor (42) being connected to the working apparatus (22), for transfer of a torque, with interposition of a shiftable transmission (50; 150) comprising at least two gearing stages having different torque transfer ratios, is characterized in that by means of a first gearing stage of the shiftable transmission (50), an input shaft (48), coupled on the input side to the drive motor (42), of the shiftable transmission (50) is connectable in torque-transferring fashion directly to an output shaft (52), coupled on the output side to the working apparatus (22), of the shiftable transmission (50) so as to rotate together at the same rotation speed; and by means of a second gearing stage of the shiftable transmission (50), the input shaft (48) is connectable in torque-transferring fashion, with interposition of a transmission assemblage (64), to the output shaft (52) so as to rotate together at different rotation speeds.

An earth working machine (10), encompassing a drive motor (42) and a working apparatus (22) drivable by the drive motor (42) so as to move rotationally, the drive motor (42) being connected to the working apparatus (22), for transfer of a torque, with interposition of a shiftable transmission (50; 150) comprising at least two gearing stages having different torque transfer ratios, is characterized in that by means of a first gearing stage of the shiftable transmission (50), an input shaft (48), coupled on the input side to the drive motor (42), of the shiftable transmission (50) is connectable in torque-transferring fashion directly to an output shaft (52), coupled on the output side to the working apparatus (22), of the shiftable transmission (50) so as to rotate together at the same rotation speed; and by means of a second gearing stage of the shiftable transmission (50), the input shaft (48) is connectable in torque-transferring fashion, with interposition of a transmission assemblage (64), to the output shaft (52) so as to rotate together at different rotation speeds.

To provide a simple-structured tensioner that can maintain good sliding properties of and hydraulic pressure for the plunger. The tensioner 10 includes a sleeve 30 inserted into a cylindrical body hole 21, a plunger 40 inserted in the sleeve 30 such as to be able to advance and retract along an axial direction of the sleeve 30, and biasing unit 60 for biasing the plunger 40 toward a front side. The sleeve 30 has, at a front end of a sleeve body 31 thereof, a flange part 33 extending radially outward.

A tensioner for tensioning a chain or belt span which uses two pistons. The movement of the two pistons may be coupled together. The first piston provides damping to the chain span and a second piston provides variable, dominant and automatically adjusting spring force to the chain span. The tensioner automatically adjusts the mean tension force to keep the chain or belt tension as low as possible without sacrificing chain or belt control, significantly improving drive efficiency at new chain or belt conditions and conditions with dynamic loads.

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 drive belt compensating tensioning device, comprising: a base frame portion comprising a square or rectangular planar bottom surface and a top surface; a vertical frame portion affixed to the base frame portion forming about a 90 degree angle with the base frame portion thereof; a pivot assembly affixed to a top end of the vertical frame portion; a tensioner arm horizontally pivotally affixed to the pivot assembly; a belt tensioning wheel rotatably affixed to the tensioner arm; a lower pivot arm rotatably affixed to the base frame portion; a cam adjustment portion rotatably affixed to a first aperture of the lower pivot arm; a first horizontal frame portion comprising an lower pivot arm engagement portion; and a spring comprising a spring first end and a spring second end.

An assembly comprising: a fixed support such as an engine block, a plurality of pulleys mounted rotatably on the support a belt mounted on said pulleys a tensioner comprising: a plate a rotary element mounted on the plate via a rotating shaft fixed relative to said plate, the tensioner being capable of turning relative to the support, in a predefined direction of rotation, between an idle position in which the rotary element is separated from the belt and an operating position in which the rotary element is in contact with the belt, it being specified that, in the operating position, the belt exerts a force on the rotary element, the direction of said force tending to rotate the tensioner in said same predefined direction of rotation; at least one stop for preventing the tensioner from rotating in the predefined direction of rotation beyond the operating position of same, the latter thus being defined by the stop; wherein in order to rotate the tensioner relative to the support between the idle position and the operating position of the tensioner, the assembly comprises: at least one closed port arranged on the plate of the tensioner or on the support at least one means for engaging with the or each closed port, said engaging means being fixed relative to the support when the closed port is located on the plate or fixed relative to the plate when the closed port is located on the support.