Safety switch for guarding accesses

A safety switch, comprising:

• a switching device (2) adapted to be anchored to a fixed part of the access to be monitored and housing there inside switching means for controlling one or more command and/or service circuits of a machine or plant;
• a driving device (3) adapted to be anchored to a movable part of the access and adapted to interact with said switching means at an opening/closing of the access for opening/closing the one or more command and/or service circuits of the machine or plant;
• locking/releasing means (23) of said driving device (3) adapted to lock said driving device (3) with respect to said switching device (2) to prevent opening of the access;
• wherein said driving device (3) comprises at least one interaction element (17) adapted to fit into at least one slot (20) of said switching device (2) to interact with said locking/releasing means (23);
• wherein said locking/releasing means (23) are provided with a locking element (40) adapted to translate in said switching device (2) along a predetermined axis (A) to engage said interaction element (17) at least in a locking position wherein said interaction element (17) is locked on said switching device (2) and in a holding position in which said interaction element (17) is removable from said switching device (2);
• wherein said locking element (40) comprises at least one pair of mutually fastened and relatively translatable elements along said axis (A),
• wherein a first one of said pair of mutually fastened and relatively translatable elements is a locking pin (24) adapted to engage said interaction element (17) at least in said locking position,
• wherein said locking pin (24) is movable at least between a first non-operative release end position in which said locking element (40) does not engage said interaction element (17) and a second locking operative end position of said interaction element (17) corresponding to said locking position of said locking element (40),
• wherein said at least one pair of mutually fastened and relatively translatable elements is movable in an intermediate position corresponding to the holding position of said locking element (40),
• wherein a retaining force exerted by said locking pin (24) on said interaction element (17) in said second locking operative end position is higher than a force exerted by said at least one pair of mutually fastened and relatively translatable elements on said interaction element (17) in said intermediate position.