Patent ID: 7252307

Claim:
A tension detecting device detecting tension applied in a longitudinal direction of a strip-shaped belt member, the device comprising: a detected base plate formed in a shape of a plate having a hole passing therethrough in a direction of thickness thereof, the detected base plate having, at a position set apart from the hole, a belt member attachment region to which the belt member is attached, and due to an edge portion of the hole, which edge portion is at a side opposite the belt member attachment region, engaging with an engaging member, the detected base plate resists tension applied to the belt member; a first strain gauge mounted to the detected base plate between the hole and the belt member attachment region, and causing its own electrical resistance value to increase in accordance with extension of the detected base plate due to tension; and a second strain gauge mounted to a region of the detected base plate which region is at a side of the hole opposite a side where the belt member attachment region is located, and causing its own electrical resistance value to decrease in accordance with contraction of the detected base plate due to the tension.