Fence unit for a prison compound has a jib projecting at the top of the upright carrier, with a signal transmitter between it and a projecting stretch metal component to generate an alarm signal for a sensor on detecting a weight

摘要

The fence unit (1) has an upright carrier (2,5), with a jib (6) to carry a stretch metal (7) component projecting over the end of the jib. A signal transmitter (19) is between the jib and stretch metal cover, which is activated by pressure on the projecting end (13) against the jib to generate a signal. The signal transmitter is at the free end of the jib, and the signal sensor (21) is at the free end of the jib or the foot (3) of the supporting carrier.