Abstract: A tensioner, for a timing chain, belt or the like in an internal combustion engine, has a projection-preventing hook that secures a spring-urged plunger in a withdrawn condition prior to installation of the tensioner, but releases the plunger during operation so that the plunger can exert a force on a pivoted chain- or belt-engaging tensioner lever. A resisting member is provided on a fulcrum pin on which the hook is pivoted, in order to exert a frictional force on the hook, thereby preventing the hook from unexpectedly returning to its plunger latching condition and preventing vibration noise to movements of the hook. The tensioner can be mounted without regard to its direction, and therefore a threaded mounting can be used, simplifying mounting and demounting of the tensioner.

Abstract: A toothed belt power transmission system includes a toothed belt having evenly spaced teeth adapted to mesh with evenly spaced teeth on a toothed pulley for power transmission. The belt teeth have a curved engagement surface including a convexly arcuate tip portion and a concavely arcuate root portion that come in sliding contact with a concavely arcuate root portion and a convexly arcuate tip portion, respectively, of a curved engagement surface of the pulley teeth in such a manner that a space is defined between the confronting engagement surfaces of the belt and pulley teeth. By virtue of the space thus formed, air confined between the belt tooth and pulley tooth is allowed to escape in the transverse direction of the belt and does never produce bursting sound at the mesh of the belt tooth with the pulley tooth. In this instance, the air serves also as a pneumatic damper and thus suppresses the impact force.

Abstract: A tensioner, for a timing chain, belt or the like in an internal combustion engine, has a projection-preventing hook that secures a spring-urged plunger in a withdrawn condition prior to installation of the tensioner, but releases the plunger during operation so that the plunger can exert a force on a pivoted chain- or belt-engaging tensioner lever. A resisting member is provided on a fulcrum pin on which the hook is pivoted, in order to exert a frictional force on the hook, thereby preventing the hook from unexpectedly returning to its plunger latching condition and preventing vibration noise to movements of the hook. The tensioner can be mounted without regard to its direction, and therefore a threaded mounting can be used, simplifying mounting and demounting of the tensioner.

Abstract: A toothed belt power transmission system includes a toothed belt having evenly spaced teeth adapted to mesh with evenly spaced teeth on a toothed pulley for power transmission. The belt teeth have a curved engagement surface including a convexly arcuate tip portion and a concavely arcuate root portion that come in sliding contact with a concavely arcuate root portion and a convexly arcuate tip portion, respectively, of a curved engagement surface of the pulley teeth in such a manner that a space is defined between the confronting engagement surfaces of the belt and pulley teeth. By virtue of the space thus formed, air confined between the belt tooth and pulley tooth is allowed to escape in the transverse direction of the belt and does never produce bursting sound at the mesh of the belt tooth with the pulley tooth. In this instance, the air serves also as a pneumatic damper and thus suppresses the impact force.

Abstract: A tensioner lever for applying tension to an endless power transmission in the form of a chain, belt or the like, comprises an elongated arm made of aluminum and having I-shaped cross-sections in section planes transverse to its direction of elongation.

Abstract: A device for applying tension to an endless chain, belt or the like comprises a ratcheted plunger having a substantially planar face disposed in substantially perpendicular relationship to the axis of movement of the plunger, and a chain or belt-engaging lever having a pad with a convex face arranged to contact the substantially planar face of the plunger. Vibrational forces exerted by the lever on the tensioner are substantially parallel to the axis of movement of the plunger, so that wear of the plunger and plunger guide are significantly reduced.

Abstract: A tensioner lever for applying tension to an endless chain, belt or the like comprises an elongated arm and a plastic shoe, having at least one L-shaped element engaging both the back face and one side edge of the arm, at least one projection engaging the opposite side edge of the arm, and a U-shaped end hook engaging an end of the arm.