SAFETY DEVICE FOR USE IN POWER OPERATED APPARATUS ESPECIALLY DOORS GUARDS AND THE LIKE

摘要

A safety device for use in detecting an obstruction in a power operated door comprises a signaller arranged to detect an obstruction. The signaller includes a pair of electrodes and the device is arranged so that a quiescent current flows from one electrode to the other. If the signaller is damaged the current is reduced or interrupted. If the signaller is compressed to indicate an obstruction the current is increased. Malfunction of the safety device may thus be detected.