Patent ID: 7527572

Claim:
A chain tensioner comprising: a housing having a cylinder chamber; a plunger slidably mounted in said cylinder chamber and defining a pressure chamber in said cylinder chamber in the back thereof; a spring mounted in said cylinder chamber and biasing said plunger outwardly of said cylinder chamber; wherein said housing is provided with an oil supply passage communicating with said cylinder chamber for supplying hydraulic oil into said pressure chamber to damp a force applied to said plunger against the force of said spring; wherein said plunger has a radially extending locking pin at its lower portion near its front end; wherein said housing includes a protrusion disposed below said cylinder chamber near the front end thereof and having first and second opposite sides disposed opposite each other in a transverse direction with respect to an axis of said cylinder chamber; wherein a pin hole extends through said protrusion in said transverse direction with respect to the axis of said cylinder chamber from said first side to said second side of said protrusion; wherein a support pin is inserted in said pin hole so as to extend through said protrusion below said cylinder chamber in said transverse direction with respect to the axis of said cylinder chamber, and a locking lever is supported on said support pin so as to be pivotable about said support pin, said locking lever being capable of engaging said locking pin when said plunger is sufficiently pushed into said cylinder chamber, thereby keeping said plunger pushed in said cylinder chamber; wherein said locking lever comprises a pair of parallel side members each having a front end and a rear end, and pivotally supported at the rear ends thereof on said support pin, and a bar extending between and coupling the front ends of said side members so as to be substantially perpendicular to said side members; and wherein said side members of said locking lever are disposed on said first and second opposite sides, respectively, of said protrusion.