A pressure-responsive variable electrical resistive rubber material including at least one inorganic filler selected from a group consisting of conductive carbon black, short fibers of nonmetallic inorganic material, powder, and whiskers. The filler is dispersed in a matrix formed of an electrically...http://www.google.de/patents/US4765930?utm_source=gb-gplus-sharePatent US4765930 - Pressure-responsive variable electrical resistive rubber material
