Protective device, particularly for a lock of a door or leaf

A protective device for a lock of a door or leaf, comprising:

• a covering element which is associated slidingly with a plate which can be fixed to said door or leaf and can be positioned selectively so as to close an opening for access to said lock which is provided in said plate;
• one or more pins associated transversely with said plate and adapted to block temporarily sliding of said covering element;
• at least one cam, rotatably mounted freely within a cavity provided in said plate;
• at least one first recess and at least one second recess provided on a lateral surface of said at least one cam;
• and
• said recesses having, in plan view, a mutually different shape and being adapted, respectively, to allow and prevent sliding of said covering element, wherein said at least one cam has a substantially cylindrical shape and is provided, on the lateral surface, along a generatrix, with said at least one first recess and at least one second recess, said recesses being substantially semicircular in plan view,
• said at least one cam being associated with one or more first magnets and having, on the lateral surface, said at least one second recess which differs from said at least one first recess in that said at least one second recess has, in plan view, a semicircular shape with a diameter that is smaller than that of said at least one first recess, and
• blocking means adapted to block or allow sliding of said covering element slidingly associated with said plate, said blocking means interacting selectively with said at least one first recess and said at least one second recess.