Patent ID: 8814233

Claim:
A machine installation comprising: a machine capable of being operated in an automated manner, said machine defining a hazardous area during operation in said automated manner, a guard door for safeguarding the machine, said guard door having an open position providing access to the hazardous area and a closed position preventing access to the hazardous area, said guard door abutting on a mating door piece in the closed position, a safety switch for generating a system enable signal when the guard door is in the closed position, and a safety switching controller for controlling operation of the machine as a function of the system enable signal; said safety switch comprising: a door part fastened to the guard door and comprising a bolt movable between a first position and a second position, and a frame part fastened to the mating door piece and connected to the safety switching controller via multi-channel redundant signal lines, the frame part comprising a recess formed in said frame part and in which the bolt engages in the second position, a locking element movable between a third and a fourth position and designed to latch the bolt in the second position for locking the guard door in the closed position, an actuator for moving the locking element from the third to the fourth position, said locking element latching said bolt when in the third position, a first position sensor designed to detect when said bolt is in at least one of the first and second positions and to transmit via said multi-channel redundant signal lines a first sensor signal to the safety switching controller in dependence thereon to indicate when the guard door is in the closed position and said bolt is in said at least one of the first and second positions, and a door release unit integral to the frame part and configured to transmit via said multi-channel redundant signal lines a door release request signal in addition to the system enable signal, said door release request signal signaling to the safety switching controller a request to provide a drive signal that operates the actuator to move the locking element from the third position to the fourth position.