DEVICE FOR DETECTION OF INTRUSION Russian patent published in 1998 - IPC

FIELD: security systems. SUBSTANCE: device has two cups, inner cup is inserted into outer cup from its open end and is connected to outer cup by spring lock which is designed as at least one strip projecting from piece of wall of open end of inner cup in perpendicular to cup axis and separated by its length from adjacent wall by groove which comprises projection which is made from piece of wall of external cup is shaped as triangle in cross section which bottom face and lateral faces form acute or right angle with respect to side wall of cup. Bottom part of inner cup and outer cup side adjacent to it have greater diameter. EFFECT: increased reliability of design. 2 dwg