| 摘要 |
The cam switch mechanism which is particularly appropriate for use in a pullkey where one must be able to initiate two separate switching operations, i.e. lockout and signal, enables a pull on a wire at either end of the unit to trigger a first response, e.g. lockout, but still permits further pulls on the wire to trigger repeated second responses, e.g. signal. First and second microswitches are actuated via independent cam followers whose movement is controlled by linear sliding cams connected respectively to the pullwires at opposite ends of the unit. Each cam comprises two parallel cam plates with the four plates interleaved so that recessed zones in the plates control movement of the cam followers. A manually controllable actuator, such as a lockout knob, may be provided to actuate the first microswitch independently of the movement of the linear cams without inhibiting subsequent sliding movement of the linear cams. In the case of a latching pullkey the lockout knob has pins projecting into holes in the linear cams so that relative movement of the cams automatically causes mechanical latching of the lockout knob in a position in which it can only be reset manually. For a non-latching pullkey the pins are omitted. |
