Sponge compressed to electrically conducting state - has conducting material in sponge pores and conducts when compressed, enabling use as switch pads in valve gear

摘要

The sponge material can be used in switch circuits to indicate the operate state of a piston valve or similar equipment. A singal source (32) has its circuit connections (34,36) connected to a plate (22) and a ring (26) terminal spaced apart on a mat (28) of the sponge conducting material. The mat (28) is supported under its base (30) so that when a valve mechanism (38,40,20) operates to compress the mat (28) contact is made around the signal source circuit (32,34,36) to provide an indicator or similar of the operate state of the valve or device. The sponge material (28) is an aerated synthetic material carrying the contact material but exhibiting high resistance when not compressed. Several mats or pads of the material may be used in a valve mechanism to provide several indications of the operate state of the device.