Anti-theft number plate fixing screw - has head with inclined surfaces in slots to permit tightening only and recess to receive plastics cap edge

摘要

The number plate is fixed to the vehicle by screws which can be tightened but lot loosened. The fixing screw has a threaded section and a section without thread. The threaded section has one part covered with a flexible plastic layer (20). The screw head has a domed shape with a central recess (14) for the screw driver. The recess has two shoulders running in the axial direction of the screw shank. The shoulders have gliding surfaces running upwards in an unscrewing direction. The gliding surfaces make it possible to tighten the screw but impossible to loosen. The screw head has an annular recess (13) to receive the edge of a plastic cap to cover the scre head.