Audible indication of vehicle speed - is provided by air entering whistle tube selected for particular speed limit

摘要

To avoid nervous fatigue of a vehicle driver who cannot constantly observe a conventional speedometer an indication of speed is given by emission of sound. Air entering an inlet(5) passes to hollow body(6) containing one or more whistle pipes(1). A selector(2) enables the user to select particular whistles and an adjuster screw(3) permits adjustment of the note. A dial(7) carries markings for speed limits and is adjacent to vehicle panel on which indicator is mounted. A small spring(4) permits accurate setting of the dial.