Patent ID: 7794345

Claim:
A dual backlash tensioner comprising: a support having a recess therein; a plunger slidable in the recess and connecting with a shoe extending outward from the recess; a first resilient member acting between the support and the plunger and urging the shoe outwardly; an oscillatable stop cam having first and second spaced teeth and engagable with the plunger, said stop cam being pivotally mounted on the support; and a second resilient member urging the first tooth toward engagement with the plunger; said plunger having a control portion opposing the stop cam, the control portion including a toothed rack, and an adjoining depression positioned longitudinally toward the shoe; wherein, a first backlash position includes the stop cam first tooth extending into the control portion depression and the plunger being retracted into the recess such that the plunger is free to move longitudinally relative to the first tooth and without limiting backlash of an associated chain having a first service length; and wherein a second backlash position includes the plunger being extended longitudinally from the recess and the stop cam teeth being operative to engage the toothed rack to form a ratcheting device configured to limit excessive backlash of the associated chain such that a second service length of the chain is greater than the first service length.