| 摘要 |
<p>A ratcheting driver has a shaft rotatable (1) relative to a handle (2), and a ratchet mechanism (5) between the handle and the shaft. The ratchet mechanism (51) has a body (52) fixed to the handle (2). A spur gear (57) coaxial with the shaft (1) is mounted in the body (52) so as to be rotatable about a common rotation axis (11) of the shaft and the spur gear. First and second pawls (58a,58b) are mounted on the body (52) so as to be tiltable about axes parallel to the rotation axis and on opposite sides of an imaginary plane containing the rotation axis. Each pawl has a free end between its tilting axis and the said plane, and is tiltable between an engaging position, in which its free end intersects the tip cylinder of the spur gear (57) and can abut against the flank of a gear tooth to prevent rotation of the gear (57) in one direction relative to the body (52), and a non-engaging position, in which its free end lies outside the tip cylinder. A control member (64) having first and second spring legs (76a,76b) is movable to a first ratcheting position, in which the first leg (76a) urges the first paw1 (58) to the engaging position and the second leg (76b) urges the second pawl (58b) to the non-engaging position, a second ratcheting position, in which the first leg (76a) urges the first pawl (58a) to the non-engaging position and the second leg (76b) urges the second pawl (58b) to the engaging position, and an intermediate non-ratcheting position, in which both legs (76a,76b) urge both pawls (58a,58b) to the engaging position. A control sleeve (64) rotatably mounted on the body (52), being captive between the handle (2) and the body (52), is linked to the control member (66) so that rotation of the control sleeve (64) clockwise and anticlockwise from a given position moves the control member (66) from the intermediate non-ratcheting position to the first and second ratcheting positions respectively. <IMAGE> <IMAGE></p> |
