A Brake Travel Indicator for use on a vehicle having a plurality of air brake assemblies secured to the undercarriage of the vehicle and stationary with respect thereto, responsive solely to the linear movement of the push rod clevis of each air brake assembly to provide a visible indication of excess...http://www.google.com/patents/US5226509?utm_source=gb-gplus-sharePatent US5226509 - At-a-glance brake travel indicator
