US Patent 9527380 Cap-installation signal system for filler neck cap

A filler neck cap is adapted to mate with and close a filler neck. The filler neck cap includes a closure configured to engage the filler neck, an outer handle configured to be gripped by a consumer, and a torque-transmission member configured to transmit torque applied to the outer handle by the consumer to the closure to rotate the closure relative to the filler neck during installation of the cap in the filler neck and removal of the cap from the filler neck.