| 摘要 |
<p>This specification discloses an adjustable spanner (10) comprising a handle (12) provided with a first jaw (16) at one end. A lever (22) is pivotally connected to the handle (12) and has coupled at one end a second jaw (24). The jaw (24) is coupled to the lever (22) by a link (36). The link (36) is pivotally connected at one end to the second jaw (24) and pivotally connected at another end to the lever (22). A cam (38) is carried in slot (46) formed in link (36). An elongate slot (40) is cut in a head portion (14) of the handle (18). As the lever (22) is pivoted with respect to the handle (12) the cam (38) rides in slot (40) and the jaws (16 and 24) move linearly with respect to each other. The cam (38) and slot (40) cooperate to form a locking means. The locking means has a free state corresponding to the cam (38) being disengaged from the slot (40) in which the jaws are able to move relative to each other and the locking state in which the cam (38) engages the slot (40) whereby the jaws are locked against movement away from each other. The locking means remains in the free state until the lever (22) is pivoted in a first direction relative to the handle (12) to a position where the jaws (16, 24) can grip a nut (30) or the like placed therebetween. Upon further movement in the first direction, the lever (22) then operates via the link (36) to rotate the cam (38) into engagement with the slot (40) thereby locking the jaws against movement away from each other. Upon releasing the handle, a return spring (58) rotates the cam (38) in an opposite direction lifting it away from slot (40) so as to return the locking means to the free state.</p> |
