Anti-theft device for shoes

Anti-theft device to be applied to a shoe, comprising a sensor element (52) of an alarm system, a first clamp plate (11) and a second clamp plate (12), a screw mechanism (21, 24) operatively connected to said clamp plates for tightening said plates against opposite sides of the upper leather of the shoe with said device straddling the edge of the upper leather, defining the insert opening for the user's foot, and means (36) preventing operation of the screw mechanism for displacement of the clamp plates from the tightened position, which can be actuated by means of a special tool only, characterized by a housing (10) receiving the screw mechanism including a screw bolt (21, 21') and a nut (24) threadingly engaging the screw bolt, said nut being non-rotatably guided in the housing to be axially displaced by rotation of the screw bolt, said first clamp plate being fixedly connected with said housing to be located together with the housing on the outside of the upper leather, and a sleeve (14) on said second clamp plate, mounting said second clamp plate to be located on the inside of the upper leather, for pivotal movement towards and away from said first clamp plate about an axis of said screw bolt.