Abstract: A tensioner unit comprises a tensioner body, a gasket in overlapping relationship to the tensioner body whereby the gasket can be sandwiched between the tensioner body and a mounting surface to which the tensioner body is to be secured, and a threaded mounting bolt inserted through a mounting hole in the tensioner body for securing the tensioner body to the mounting surface. A bolt hole is provided in the gasket, and the mounting bolt also extends through the bolt hole. The gasket grips the bolt and holds the mounting bolt, the gasket, and the tensioner body, in fixed relationship to one another, and maintains the gasket in a predetermined aligned relationship with the tensioner body when the gasket is in overlapping relationship with the tensioner body during mounting of the tensioner body on the mounting surface.

Abstract: In a ratchet tensioner, a linearly moving ratchet for engagement with rack teeth on a plunger is operated a piston that is spring-biased in a direction to engage the ratchet teeth with the rack, and movable by oil pressure in a direction to disengage the ratchet teeth from the rack. The piston is located within a hole in the housing and, with that hole, forms a second high pressure oil chamber that can receive oil through an oil supply path independent of the oil supply path that carries oil to a first high pressure oil chamber formed by the plunger and the tensioner housing.

Abstract: In a ratchet-type tensioner, a rocking ratchet pawl is released from a rack of teeth on a tensioner plunger following engine start-up by a hydraulically operated pin slidable in a pin hole and caused to protrude therefrom by oil under pressure received directly from an external oil supply, or alternatively from the tensioner's high pressure oil chamber through a passage in the tensioner housing. Optionally, an orifice can be provided within the pin hole to control flow of oil when the supply is excessive and to avoid leakage when the supply is insufficient.

Abstract: In a tensioner for a timing chain, a spring-biased plunger for urging a shoe into sliding engagement with the chain is temporarily held in a retracted condition, prior to installation of the tensioner, by a stopper having a pin that extends through a hole in the tensioner housing and engages a grove formed in the plunger. The stopper is bent so that its handle extends away form the pin axis at an angle greater than zero but not greater than 90°. Removal of the stopper from the tensioner can be carried out by rotating the handle to avoid interference with engine components in the vicinity of the tensioner.

Abstract: In a sliding contact chain guide of the kind used in the timing transmission of an internal combustion engine, the guide body is formed by injection molding of a synthetic resin. The guide body includes reinforcing ribs of substantially uniform width, forming a Y-shaped truss structure.

Abstract: In a tensioner for a timing chain, a spring-biased plunger for urging a shoe into sliding engagement with the chain is temporarily held in a retracted condition, prior to installation of the tensioner, by a stopper having a pin that extends through a hole in the tensioner housing and engages a grove formed in the plunger. The stopper is bent so that its handle extends away form the pin axis at an angle greater than zero but not greater than 90°. Removal of the stopper from the tensioner can be carried out by rotating the handle to avoid interference with engine components in the vicinity of the tensioner.