Chain tensioner having biased disabling mechanism

A chain tensioner comprising a housing having a bottomed cylinder portion;

• a plunger slidably assembled in the cylinder portion;
• a spring applying a biasing force to the plunger in the direction of projecting the plunger out from the cylinder portion;
• and a check valve supplying a fluid into a hydraulic compartment formed between the bottom of the cylinder portion and the plunger, to thereby prevent the counter-flow of the fluid, the chain tensioner further comprises:
• a stopper plate having a through-hole formed therein, through which the plunger is inserted;
• a check valve fixing hole defined in a radial outer surface of the housing, the check valve fixing hole being in communication with a fluid supply unit via a groove shaped passageway defined in an end face of the housing, the passageway extending from the check valve fixing hole to the fluid supply unit laterally relative to a longitudinal axis of the check valve fixing hole, wherein the check valve is press-fit into the check valve fixing hole and faces an outer circumferential surface of the plunger, an inner face of the check valve defining part of an inner circumferential surface of the cylinder portion along which an outer circumferential surface of the plunger makes direct sliding contact;
• and
• a biasing member disabling movement of the plunger, by applying a biasing force to the end of the stopper plate so as to incline the stopper plate,
• the chain tensioner is configured to apply a hydraulic pressure to the stopper plate, so as to reduce the inclination of the stopper plate against the biasing force applied by the biasing member, to thereby allow movement of the plunger.