A manual drive assembly for a manually-operated window treatment based on a drive chain formed as a loop, may incorporate one or more intermediate tensioners disposed between two ends of the loop. The loop may be formed between a manual clutch mechanism coupled to the window treatment and an end tensioner. The one or more intermediate tensioners may serve to limit slack in the loop such that sides of the loop cannot be pulled to create a large loop, for example, having a gap of four inches or greater, between the hanging sides of the cord.

A hydraulic tensioning device for a chain device, having a housing and having a clamping piston guided displaceably in a housing bore of the housing, the clamping piston having a piston cavity with a hardened inner circumferential surface, and also having a pressure relief valve unit arranged in the piston cavity. The pressure relief valve unit (12) is a preassemblable unit and includes a spring (18), a closing body (17) and a valve seat (16) and also a receptacle (15, 26) at least partially enclosing the valve seat (16), wherein the valve seat (16) is made of a metal material, has an at least partially hardened surface and wherein the receptacle (15, 26) forms a press-fit with the inner circumferential surface of the clamping piston (3).

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 coupling system can include an energy transfer device and a load mitigation system. The energy transfer device can include a shaft, gear, chain or piston-cylinder arrangement to transfer the energy from a power supply to an object to be moved. The load mitigation system can be used to limit or prevent the transfer of forces from the object to the drive unit as a result of external loads being applied to the object. The load mitigation system can be pre-loaded such that external loads on the object having an excessive impulsive or resonant cyclic force greater than the pre-load force on the load mitigation system are reduced and only partially transferred to the energy transfer device and power supply. The load mitigation system can dampen both resonant loads and impulsive impact loads occurring at the object thereby preventing damage and extending life.

A product for applying tension is disclosed. The product may include a block with a first bore opening into to the block. A body may be provided having a second bore substantially larger in diameter than the first bore. The body may be positioned against the block so that the first bore is open to the second bore. The body may have a passage for providing fluid to a pressure chamber from the second bore. The passage may be arranged to open to the second bore and form a tangent to the second bore. Fluid may flow from the first bore to the pressure chamber through the second bore and the passage substantially unimpeded. Fluid flow is impeded from the passage to the first bore as a result of the configuration of the first bore, second bore and passage.

A contact guard for a belt drive, in which a filling space formed between two pulleys and the belt is filled by a filling body, which includes two sub-bodies that can be moved relative to one another.

A quick-release automatic tensioning motor base for supporting a motor. The motor is operably coupled to a device to be driven via a drive belt. The motor base includes base brackets and at least one guide rail fixedly coupled between the base brackets. A platform assembly, which supports the motor, is slidably coupled to the guide rail. A spring assembly is selectively coupled between the base brackets and fixedly coupled to the platform assembly. The spring assembly applies a biasing force to the platform assembly to maintain a belt tension along the drive belt. A quick-release assembly selectively engages the spring assembly and base brackets to permit movement of the quick-release assembly between a fastened position and a released position. A spring compression retention assembly is operably coupled to the spring assembly to maintain spring compression on the spring assembly even when the quick-release assembly is in the released position.

A driving apparatus includes an endless belt, a belt roller which engages the endless belt, a steering member and an adjustment member. The belt roller has a rotation shaft. The steering member contacts the endless belt at the inner side of the endless belt. The adjustment member is supported rotatably. The adjustment member receives a force in response to the endless belt moving in a longitudinal direction of the rotation shaft of the belt roller, and generates a pressing force that tilts the steering member via a rotational movement of the adjustment member.

An autonomous hydraulic expansion and contraction apparatus comprises a fixing unit, a cylinder unit, a support unit, a piston unit, a valve unit and oil supply parts. By controlling the expansion and contraction length of the support part by a simple manipulation of the valve part by moving the lever, the autonomous hydraulic expansion and contraction apparatus can be easily expanded and contracted to the combined length of the expansion and contraction equipment, and additionally, the convenience of use can be enhanced.

An agricultural harvester has a header and feeder drive system including a forward belt drive arrangement and a reverse belt drive arrangement. The forward belt drive arrangement includes a forward drive belt and a forward belt drive tensioner operated by an actuator. The reverse belt drive arrangement includes a reversing motor and a reverse drive belt selectively engaged with the feeder drive system by operation of the same actuator.