Safety switch with lock-out device

A safety switch with a lock-out device, adapted to be mounted at an access of a perimeter protection structure of industrial machines or plants, comprising:

• a switching unit (2) adapted to be anchored to a fixed part of the structure and provided with switching contacts adapted to be operatively connected with at least one power supply circuit of the plant to be controlled for the opening/closing thereof;
• an operating unit (3) adapted to be anchored to a movable part of the structure and having an actuating unit (5) interacting with said switching contacts upon the closing of the movable part on the fixed part to enable the closing of the power supply circuit;
• a lock-out device (16) associated with said switching unit (2) and having a guard (17) movable between an inactive position, wherein the interaction between said switching contacts and said actuating unit (5) is allowed and an active position wherein said interaction is avoided;
• wherein said switching contacts and said actuating unit (5) are electronic and are respectively associated with a first communication element (6) and a second communication element (7) remotely communicating therebetween by means of a presence signal to allow said switching contacts to discriminate the presence of said operating unit (3) close to said switching unit (2);
• wherein said movable guard (17) comprises a shielding element (20) interposing itself between said communication elements (6, 7) when said guard (17) is into said active position to avoid the transmission of said signal and the closing of said switching contacts, said operating unit (3) allowing said first communication element (6) and said second communication element (7) to move into a position facing each other both when said movable guard (17) is in said active position and when is in said inactive position for closing the access to be controlled also with said movable guard (17) in said active position;
• wherein said first communication element (6) and said second communication element (7) communicate therebetween only after reaching a predetermined minimum distance sufficient for considering the protection closed, at which distance said first communication element (6) discriminates the presence of said operating unit (3) close to said switching unit (2);
• and
• wherein said lock-out device (16) allows said operating unit (3) to place said second communication element (7) at said minimum distance from the first communication element (6) also with the movable guard (17) in said active position.