Provided is a simple-structured tensioner that can reduce processing and assembling workload and maintain the tensioner performance constant, as well as store a sufficient amount of oil. The tensioner includes a plunger 20, a housing 30, an inner sleeve 40, a check valve 50, and a biasing unit 60. The inner sleeve 40 includes a cylindrical body 41 having an inner part that serves as an oil reservoir chamber 13, a sleeve bottom 42 formed at one end of the cylindrical body 41, an oil hole 43 formed in the sleeve bottom 42, and a ball seat 44 which protrudes in a cylindrical shape toward an oil pressure chamber 12 integrally with and continuously from an edge of the oil hole 43 and on which a check ball 51 is seated.

An integrated valve for a hydraulic tensioner includes a pressure relief valve with an integrated disk check valve surrounding the pressure relief valve. A hydraulic tensioner includes a housing with a bore and a hollow piston slidably received within the bore. A piston spring biases the piston in a direction toward a power transmission device. The tensioner also includes an integrated check valve in a body of the housing. The integrated check valve includes a pressure relief valve mechanism and a disk check valve mechanism surrounding a circumference of the pressure relief valve mechanism. The pressure relief valve mechanism permits transfer of pressurized fluid from a piston chamber formed by the hollow piston to the source of pressurized fluid and the check valve mechanism permits transfer of pressurized fluid from the source of pressurized fluid to the piston chamber.

A drive system for an agricultural work machine having a primary drive system configured to drive a performance system for performing a crop preparation or handling operation including a fluid motor, a fluid pump and a tensioner system. The fluid motor is configured to produce a drive force and to be driven by a flow of fluid moving through the motor. The fluid pump is operatively connected to the fluid motor and is configured to drive the fluid motor. The tensioner system is operatively connected to the fluid motor and to the fluid pump, wherein the direction of fluid flow through the fluid motor adjusts the application of at least one force applied to a belt in the drive system. The fluid motor is configured to adjust the force applied to the belt by regulating a belt tension in proportion to a torque provided by the fluid motor.

In one aspect the invention relates to a tensioner that is capable of precognitively anticipating when it is desirable to increase the tension in a belt or other endless drive element so as to prevent belt slip prior to events that would raise the risk of it.

A tension roller assembly includes a tension roller, a pivotable support arm, a tension arm, a compression spring, a rod, first and second spring stops, a mounting plate, and an overcenter assembly connected to an end of the tension arm. The overcenter assembly connects the tension arm to the mounting plate. The overcenter assembly is configured to make a pivoting movement over a pivot trajectory between engaged and disengaged positions. The overcenter assembly further has a center position located between the engaged and disengaged positions. The pivot trajectory between the center position and the disengaged position is divided into a tensioned section in which the end stop does not engage the stop surface and the spring exerts a force on the overcenter assembly, and a free-moving section in which the end stop engages the stop surface and the spring does not exert any force on the overcenter assembly.

The present invention relates to a belt installation tool which is to be installed so as to cover at least a part of a first side surface of a pulley, including an attaching part attached along an outer peripheral part of the pulley, an installation part brought into contact with at least a part of the first side surface, a protection part covering at least a part of the first side surface without coming into contact therewith, and a belt holding part protruding on the protection part or on the installation part, in which the protection part covers at least a part of a part having a largest distance in a vertical direction in an area located inside the part with which the installation part comes into contact in the first side surface.

To provide a tensioner which can circulate a sufficient amount of oil even if there is a long time lag until pressurized oil starts to be supplied, and which exhibits a lower level of leak of oil stored therein, and which is structured simply without increasing the number of components therefore. The tensioner includes: a tensioner body having a plunger bore; a cylindrical plunger slidably inserted into the plunger bore; and biasing means for urging the plunger outward. When the tensioner is fixed to a wall surface, a body hole that extends from the wall surface up to a circumferential surface of the plunger bore is located lower than an oil discharge hole in the wall surface.

A tensioner which adjusts the mean tensioner force to keep the chain tension as low as possible without sacrificing chain control, significantly improving drive efficiency as the chain wears and is subject to low dynamic loads.

A tensioner (10) for an endless loop power transmission member can induce a piston (12) operably engageable with an endless loop power transmission member, and a cylinder (14) guiding include a piston (12) for sliding coaxial movement in a direction of the endless loop power transmission member. The piston (12) and cylinder (14) defining an oil reservoir or pressure chamber (26) for receiving hydraulic fluid. A bearing (28) has bearing balls (30) located in a counter bore (32) coaxial with cylinder bore (34). The counter bore (32) has a steep taper (36) on which the bearing balls (30) ride. As the cylinder (14) moves in an extending direction, the bearing balls (30) move out of the counter bore (32) allowing free extending movement of the cylinder (14). As the cylinder (14) moves in a retracting direction, the bearing balls (30) are driven down into the steep taper (36) preventing the cylinder (14) from retracting.

A load-applying device is provided that includes a spiral spring that is formed from a thin strip that is wound multiple times in a spiral shape; a movable body; and a fixing member. The spiral spring is disposed between the movable body and the fixing member, in a manner capable of performing a diameter reduction operation and a diameter expansion operation, and an outer-circumference part of the spiral spring contacting the movable body and the fixing member directly, or indirectly.