| 摘要 |
A ratchet wrench comprises a wrench body having a handle portion and a pawl engaging surface. A ratchet gear is removably engaged with a fastener such that torque applied to the gear is transmitted to the fastener to effect rotation. The gear is mounted to the body such that the gear and the body are rotatable relative to one another about a gear axis. The gear has a plurality of gear teeth having opposing tooth surfaces. A pawl has first and second tooth engaging surfaces and a load receiving surface. The pawl is mounted to the body for pivotal movement about a pawl axis with the load receiving surface engaging the pawl engaging surface. The pawl is movable to a gear driving position wherein the first and second tooth engaging surfaces are positioned for driving engagement with respective tooth surfaces of a pair of the gear teeth. A manual force applied in a torque applying direction to the handle portion is transmitted from the body to the pawl via the engagement between the pawl engaging surface and the load receiving surface and from the pawl to the gear via the engagement between the tooth engaging surfaces and the tooth surfaces of the pair of the gear teeth so as to apply torque to the gear. In the gear driving position, a first portion of the manual force is transmitted through the pawl from the load receiving surface to the first tooth engaging surface for application to one of the gear teeth and a second portion of the manual force is transmitted through the pawl from the load receiving surface to the second tooth engaging surface for application to the other of the gear teeth with the first and second portions of the manual force being in a balanced relation with respect to the pawl axis so that the first and second portions of the manual force offset each other about the pawl axis and the pawl is compressed between the pawl engaging surfaces and the first and second tooth engaging surfaces. A biasing element is engaged with the pawl and biases the pawl to the gear driving position. A manual force applied in a ratcheting direction to the handle portion opposite the torque applying direction causes rotation of the body relative to the gear with the pawl repeatedly ratcheting over the gear teeth against the biasing of the biasing element.
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