Abstract: A one way isolator for high torque devices, such as alternator-starters, driven by a flexible drive means includes a hub and a sheave each of which includes at least one stop member. The hub and sheave are linked by a isolating spring and, via a bearing and/or bushing, can rotate with respect to each other to provide isolation, through the spring, from torque variations when torque is transferred from the flexible drive means to the device. When substantial amounts of torque are transferred from the device to the flexible drive means, the sheave rotates with respect to the hub to bring the stop members into contact such that the isolator then acts like a solid pulley to facilitate the transfer of the torque from the device.

Abstract: A tensioner for tensioning a flexible drive means, such as a timing belt or chain, includes a pulley to contact the belt. The pulley is mounted on a tensioner arm and the tensioner arm can be rotated about a pivot shaft mounted to the tensioner by a spring. The axis about which the pulley rotates is spaced from the axis of the rotation of the tensioner arm with respect to the pivot shaft and the spacing of these axes of rotation results in the pulley moving through an eccentric towards or away from the belt when the tensioner arm is rotated. A stop is used to limit the range of movement of the tensioner arm between a desired range of movement defined by a free arm stop and a backstop. The position of the stop is adjustable by an installer. The angular range of movement of the tensioner arm is adjustable from a position suitable for installation of the tensioner to a position suitable for operation of the installed tensioner.

Abstract: A tensioner enables easy and reliable reinstallation of the tensioner and belt in the field service while simultaneously making it possible to utilize a one-way clutch device to ensure continuous belt tension control without cumbersome manual alignment and/or realignment procedures. The tensioner has a pivot shaft configured for mounting on an engine surface. A tensioner arm is mounted on the pivot shaft for pivotal movement between a free arm stop position and premount stop position. A belt-engaging pulley is mounted for rotation on the tensioner arm. A base cup is rotatably mounted around an end of the pivot shaft. The base cup has an arcuate slot having a free arm stop end and a premount stop end. The tensioner arm cooperates with the arcuate slot limiting the pivotal movement of the tensioner arm. A spring is coupled between the tensioner arm and the base cup biasing the tensioner arm in a belt-tensioning direction.

Abstract: A belt tensioning device having an improved damping mechanism for damping movements of the pivoted structure rotatably carrying the pulley with respect to the fixed structure. The damping mechanism includes a strap and a ring mounted on their respective fixed and pivoted structures and with respect to one another such that the strap engages the ring with a gripping action sufficient to provide (1) a relatively high resistance to frictional sliding movement between the strap and ring in one direction correspond to the direction of untensioning of the belt with the pulley and (2) a relatively low resistance to frictional sliding movement between the strap and ring in an opposite direction corresponding to the direction of belt tensioning.

Abstract: A belt tensioner in which the bearing for mounting the pulley carrying pivoted structure on the fixed structure comprises a frustoconical sleeve bearing having a frustoconical exterior surface and a frustoconical interior surface engaged between annular portions of the two structures. The frustoconical surface of one of the annular portions is (1) formed on the exterior periphery thereof and (2) disposed in engagement with the interior bearing frustoconical surface. The one annular portion has a load center point disposed on the pivotal axis of the pivoted structure. The other annular portion has a load center point disposed on a line disposed within a plane passing through the pivotal axis of the pivoted structure and the rotational axis of the pulley corresponding to the one line of the two lines of intersection of the bearing frustoconical surface with the plane through which the radially inward force component transmitted by the pivoted structure is applied to the sleeve bearing.

Abstract: In a belt tensioning device comprising a fixed structure, a pivoted structure mounted with respect to the fixed structure for pivotal movement about a first axis between first and second limiting positions, a belt engaging pulley rotatably carried by the pivoted structure for rotational movement about a rotational axis parallel with the pivotal axis, a spring acting between the fixed and pivoted structures for resiliently biasing the pivoted structure to move in a direction away from the first limiting position toward the second limiting position so as to tension a belt engaged by the pulley, and a damping mechanism for damping the pivotal movements of the pivoted structure about the pivotal axis. The damping mechanism includes a stack of damping elements having interengaging pairs of surfaces disposed transversely with respect to the pivotal axis so as to be slidable with respect to one another in spaced planes of revolution about the pivotal axis.

Abstract: A timing belt tensioning device comprising a fixed structure having a spring pressed pivoted structure mounted thereon for pivotal movement about a first axis between first and second limiting positions. The pivoted structure carries a timing belt engaging pulley for rotational movement about a second axis parallel with the first axis. A one-way clutch mechanism is provided for permitting pivotal movement of the pivoted structure in a direction toward a second limiting position and for limiting the pivotal movement of the pivoted structure in an opposite direction toward the first limiting position beyond a predetermined distance measured from the nearest position of the pivoted structure to the second limiting position.

Abstract: In a belt tensioning device of the type including a fixed structure, a pivoted structure mounted with respect to the fixed structure for pivotal movement about a first axis between first and second limiting positions, a belt engaging pulley rotatably carried by the pivoted structure for rotational movement about a second axis parallel with the first axis and a torsional coil spring acting between the fixed and pivoted structures for resiliently biasing the pivoted structure to move in a direction away from the first limiting position toward the second limiting position with a spring force which decreases as the pivoted structure is moved in a direction away from the first position toward the second position.