Patent ID: 8137225

Claim:
A chain tensioner device comprising: an endless chain; a main arm pivotably supported by a first support shaft and brought into slide contact with the endless chain to apply a predetermined tension to the endless chain, the endless chain being wrapped around a drive sprocket provided on a driving shaft and a follower sprocket provided on a follower shaft; a tensioner lifter that generates a biasing force for biasing the main arm toward the endless chain; and a sub-arm pivotably supported by a second support shaft, the sub-arm transferring the biasing force of the tensioner lifter to the main arm, wherein a first slide surface provided on the main arm and a second slide surface provided on the sub-arm slidably abut against each other to increase a stroke of the tensioner lifter and transfer the stroke to the main arm, wherein the main arm has a first bump and the sub-arm has a second bump, the first slide surface being defined along the first bump and the second slide surface being defined along the second bump, and wherein the first slide surface of the main arm abuts against the second slide surface of the sub-arm from a side of the second support shaft.