US Patent 7434493 Ratchet driving mechanism with two sets of pawls

A ratchet driving mechanism includes a main body, an adjusting ring, and a ratchet wheel. The main body includes a grip-connecting member and a rotary seat connected fixedly to the grip-connecting member. The rotary seat is formed with two parallel insertion slots, in each of which two pawls are biased by a spring to move away from each other. The adjusting ring and the ratchet wheel are sleeved rotatably on the rotary seat. When the adjusting ring is disposed in an anchoring position, the pawls engage the ratchet wheel so as to prevent rotation of the ratchet wheel on the rotary seat. When the adjusting ring is disposed in a first-direction position or a second-direction position, two of the pawls engage the ratchet wheel so as to allow for rotation of the ratchet wheel on the rotary seat in only a corresponding direction.