A tensioning bar assembly for a tensioning assembly of a drive system of an agricultural machine includes a longitudinal bar having a longitudinal axis, a top end, and a bottom end. An attachment device is attached to the top end of the longitudinal bar. A compression spring has first and second ends, and is located around a portion of the longitudinal bar. A first spring retainer engages with and retains the first end of the spring. The longitudinal bar has a bolt section, and the bolt section has a threaded portion, an engagement head, and a sleeve section. The sleeve section includes an internally threaded hollow section for receiving the bolt section. The sleeve section is fixed and rotationally attached to the attachment device.

An orbital tensioner comprising an annular base, a ring journalled to the annular base on a ball bearing, said ring having a ring axis of rotation (A-A), a first pulley journalled to the ring, a first pulley axis of rotation (B-B) offset from the ring axis of rotation (A-A), a pivot arm pivotally mounted to the ring, a pivot arm pivot axis (C-C) offset from the ring axis of rotation (A-A), a second pulley journalled to the pivot arm, a torsion spring biasing the pivot arm in a first direction, the ball bearing having a first race and a second race, the ring fixed to the first race, the annular base fixed to the second race, and a damping mechanism frictionally disposed between the ring and the base.

Described embodiments include a reconfigurable belt tensioner that can be used to add, remove, and/or reposition peripheral accessories of an engine installation, for example, in an automobile or another vehicle. The tensioner has a housing, an arm with an axle, and a spring installed in the housing. The axle is inserted into and fastened to the housing. The arm rotates around the axle. When the arm is rotated, the spring provides the force that tends to return the arm and the housing to the original position. The tensioner can be reconfigured by repositioning the spring relative to the housing and/or the arm, changing the angle between the housing and the arm. The tensioner may be used, for example, on an LS-based GM small-block engine, and allow operation with and without the air conditioning compressor or other accessories.

A tensioner comprising a base having a base aperture, the base aperture having an axis A-A and capable of receiving a driven component, a rotary arm rotatably engaged with the base and encircling the base aperture, a swing arm pivotally engaged with the rotary arm, a first torsion spring biasing the swing arm, a first pulley journalled to the swing arm, a rotary ring rotatably encircling the base aperture and disposed between the rotary arm and the base, a second pulley journalled to the rotary ring, a second torsion spring engaged between the rotary ring and the rotary arm for biasing the rotary ring, and a wave spring in pressing engagement between the base and the rotary ring.

A tensioner includes a movable section, a fixed section, a flat spiral spring, and a back-up spring. The movable section receives load from an entrained transmission body through a tension member. The fixed section supports the movable section so as to be capable of displacing. The flat spiral spring biases the movable section so as to resist the tension member. The flat spiral spring unwinds in a state in which there is a small inter-plate friction force in cases in which there is a large biasing force applied to the tension member to counter load acting from the tension member. The flat spiral spring winds-up in a state in which there is a large inter-plate friction force in cases in which there is a small biasing force applied to the tension member to counter load acting from the tension member. The back-up spring limits wind-up of the flat spiral spring.

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).

A tensioning bar assembly for a tensioning assembly of a drive system of an agricultural machine, including a longitudinal bar having a longitudinal axis, a top end and a bottom end, an attachment device attached to the top end of the longitudinal bar, a compression spring having first and second ends, the spring located around a portion of the longitudinal bar, and a first spring retainer for engaging with and retaining the first end of the spring, where the longitudinal bar has a bolt section, and the bolt section has a threaded portion, an engagement head, and a sleeve section, and the sleeve section includes an internally threaded hollow section for receiving the bolt section, and the sleeve section is fixed and rotationally attached to the attachment device.

To provide a tensioner that has a simple structure and is easy to assemble, and is configured to smoothly relieve pressure during oil release with reduced flow resistance so that the oil pressure in an oil pressure chamber is kept stable in a favorable manner. A relief valve unit includes a cap member that fits with a seat member to retain a stopper member inside the seat member. An external relief hole, which causes a relief-side space in a plunger hole to communicate with the outside of a plunger, opens radially in an outer circumferential surface of the plunger.

A tensioner comprising a base having a base aperture, the base aperture having an axis A-A and capable of receiving a driven component, a rotary arm rotatably engaged with the base and encircling the base aperture, a swing arm pivotally engaged with the rotary arm, a first torsion spring biasing the swing arm, a first pulley journalled to the swing arm, a rotary ring rotatably encircling the base aperture and disposed between the rotary arm and the base, a second pulley journalled to the rotary ring, a second torsion spring engaged between the rotary ring and the rotary arm for biasing the rotary ring, and a wave spring in pressing engagement between the base and the rotary ring.

A chain transmission device for driving camshafts includes a chain including a loose side chain portion, and the chain is trained around the crank sprocket and the cam sprockets. A chain guide is mounted on the outer side of the loose side chain portion so as to be pivotable about one of the two end portions of the chain guide, and the chain guide has a plurality of rotatable rollers. An adjustment force is applied to the other of the two end portions of the chain guide by a chain tensioner such that the chain guide is biased toward the chain, so that the rollers of the chain guide can guide the chain by rolling. The winding angle of the portion of the chain located on the outer periphery of the roller located closest to the crank sprocket is set to be 170 degrees or greater so as to reduce noise.