| 摘要 |
A piston operated by a cable stretched out within hand reach along a dangerous zone actuates a tappet whose movements are transmitted to a slider. The slider in turn compresses a spring until in a first phase, before any switch actuation, a pawl engages a groove in the slider. This prevents return of the tappet to its rest position, whereby any attempt to simulate a machine breakdown by fraudulent actuation of the device leaves a trace in the device even before effective switch actuation has occurred. In a second phase the force of the spring exceeds the force necessary to retract locking pins of a striker which is therefore released abruptly to operate the switch. To restore the device to its standby state, a lock plug carrying a cam adapted to release the pawl from the groove in the slider is rotated by means of a key.
|
