Patent ID: 7600449
Filing Date: 2009-10-13
Classification: B25B

Abstract:
1. A power adjustable wrench comprising a wrench body, an adjustable jaw, a driving control circuit including an electromotor, a power supply, a switch and a gear transmission mechanism, a fixed jaw being provided at the front end of the wrench body, the fixed jaw being connected with the adjustable jaw to form a adjustable jaw space, the adjustable jaw having worm gear teeth on the bottom thereof to engage with a worm for driving the adjustable jaw back and forth, an output end of the gear transmission mechanism being connected with the worm, the gear transmission mechanism being a gear reducer with at least three pairs of reduction gears; wherein the switch for controlling positive and reverse rotation of the electromotor comprises: a button with two return springs at two ends respectively, the button has two parallel conductive contact blocks on the bottom of the button; a circuit board having metal foils on face and back sides thereof is located under the conductive contact blocks; the face metal foil forms a pair of output contact pieces at the upper part, a pair of input contact pieces at the middle and a pair of transmission pieces at the lower part, which are arranged in parallel, a pair of input terminals are riveted on the side of the circuit board against the button; the back metal foil forms a pair of connecting pieces for connecting the pairs of input terminals with the pair of input contact pieces, forms a pair of connecting pieces for reversely switch-connecting the transmission contact pieces with the output contact pieces; thereby, an output is positive when the button moves upwards and an output is negative when the button moves downwards.