| 摘要 |
A latch arrangement 10 comprising a transmission path 30 which selectively connects a handle 26, 28, or other manually operable member, to a retaining member, such as a pawl, of a latch bolt 12. The transmission path comprises an intermediate member 34 (shuttle), a first part 32 coupled to the handle, a second part 36 coupled to the pawl. The first and second parts have first and second abutment surfaces 40, 44, respectively which are proximate to the intermediate member when it is in a rest position. When the handle is operated whilst the latch is unlocked the abutment of the first part engages the shuttle and moves it from the rest position to a first actuated position in which it abuts and moves the second part which releases the pawl. When operated whilst the latch is locked the first part engages the shuttle which moves from the rest position to a second actuated position in which it does not engage the second part and the latch remains retained by pawl. Preferably in the unlocked position the shuttle is biased to slide in a first direction (fig.5) by abutments (75, 77, fig.5) and torsion spring whereas in the locked position an electromagnet 72 selectively holds a link (68, fig.5) causing shuttle to pivot in a second direction upon operation of the handle (fig.6). |
