| 主权项 |
1. A ratchet wrench comprising:
a body having a handle, a function head connected to an end of the handle, the function head having a first recess defined therethrough, a second recess defined in an inner periphery of the first recess, a center of the second recess being located within the first recess, the second recess having a closed top and a close bottom, a third recess defined in an inner periphery of the second recess, the third recess communicating with a top of the function head, the third recess having a center at a center thereof, an opening defined in the top of the function head and communicating with the third recess, the opening located between a first plane face and a second plane face, an extension line from the first plane face and an extension line from the second plane face intersecting at an intersection point, a distance between the intersection point and the first recess being shorter than a distance between the center and the first recess, the function head having an end face on a top thereof, a first angle defined between the first and second plane faces, the first angle being within a range between 60 to 80 degrees, a groove defined in an inner periphery of the first recess; a ratchet wheel rotatably received in the first recess and having a toothed portion defined in an outer periphery thereof, the toothed portion having multiple teeth, an engaging groove defined in the outer periphery of the ratchet wheel, the ratchet wheel having a mounting portion formed at a center thereof; a pawl movably located in the second recess and having a driving portion formed in a front side thereof, the driving portion having multiple teeth and multiple curved teeth, the teeth of the driving portion of the pawl engaged with the teeth of the ratchet wheel, when the curved teeth are located between two of the teeth of the ratchet wheel, the curved teeth are tangent to the two teeth of the ratchet wheel, a bottom of each of the teeth and the curved teeth of the pawl being located along a second curve, two to four curved teeth being located at each of two ends of a row of the teeth of the pawl, a top of each of the teeth of the pawl being located along a first curve, the first curve, the second curve, the first recess and the ratchet wheel sharing a common center, a third curve located between the first and second curve, a top of each of the curved teeth being tangent to the third curve, a curved recess defined in a rear side of the pawl and a protrusion located on an upper portion of the curved recess, the protrusion having a contact face at an underside thereof, the pawl having a first height and the protrusion having a second height which is smaller than a half of the first height, a radius of the third curve is a half of a sum of a radius of the first curve and a radius of the second curve; a switch unit located in the third recess to control a movement of the pawl in the second recess, the switch unit having a switch member, an end piece and a resilient member, the switch member having a cylindrical member which is rotatably located in the third recess, the cylindrical member having a restriction groove which is located corresponding to the curved recess, the switch member having a second end face on a top thereof, the second end face being in flush with the first end face, a lever extending from the switch member and located in the opening, the lever having a third plane face and a fourth plane face respectively formed on two sides thereof, the third plane face contacting the first plane face, the fourth plane face contacting the second plane face, the end piece and the resilient member located in the restriction groove, the resilient member located between the end piece and the restriction groove, the end piece being biased by the resilient member and contacting against an inner side of the curved recess, an outside of the end piece contacting the contact face of the pawl to position the switch unit in the third recess, the end piece being restricted by the second height of the protrusion to make the end piece aim a central portion of the pawl and a mediate portion of the first height, and a C-shaped clip being engaged with the groove of the body and the engaging groove of the ratchet wheel to position the ratchet wheel in the first recess. |
