Fire alarm signalling unit - automatically sends signal when transparent panel is broken by release of switch lever under spring pressure

摘要

The unit has a tray-shaped housing and a cover plate with a window aperture. A T-shaped transparent panel is supported and held in place by pillars and a groove so that a weakening groove in the panel is centred in the window. When installed, the edge of the panel retains the spring-loaded lever of a switch assembly, which is mounted on pillars in the housing. An alarm is generated by a manual blow to the panel which cracks along the groove. The switch lever is then forced out by spring pressure and becomes visible in the window. The switch is connected via a circuit board and cable to an external alarm system.