Command or alarm unit e.g. for installing in switchboards

摘要

A command or alarm unit for installation in a switch panel is attached by a threaded shaft with a nut. On its surface, the shaft (2) has contact faces (4) which align with and touch corresponding conducting rails on the front plate of the panel. The contact faces are at right angles to the rails. There is a contact ring(6) joining the contact faces. This is embedded in a recess of the nut. The unit is a push button with a pushrod that interrupts a light barrier, the latter being integrated in the housing. The unit has a transistor-controlled light unit. The rails carry the supply voltage and are also connected to a decoder/encoder device.