Patent ID: 7992706

Claim:
A tensioning device configured for use in a conveyor system as an idler roller over which a belt is wound under tension, comprising: a housing, an arm disposed in the housing for linear movement into and out of the housing; a roller mechanism mounted at a distal end of the arm, including a roller configured for rolling contact with a belt of a conveyor system; an actuator for extending and retracting the arm from the housing, the actuator including a worm shaft and a lead screw wherein a pinion of the worm shaft engages a gear affixed at one end of the lead screw; a coupling by which rotation of the lead screw results in outward movement of the arm when the worm shaft is rotated in a first direction, and which results in inward movement of the arm when the worm shaft is rotated in a second direction opposite the first direction; and wherein engagement of the worm shaft to the gear is self-locking.