Know Your Speed.

Progress, Volume I, Issue 5, 1 March 1906, Page 107

Know Your Speed.

An effective and accurate speed indicator is an accessory that undoubtedly adds much to the pleasures of the push-pedal and the motor bicycle. Such an instrument is illustrated herewith, the originator being Mr. Robert Goodlad, an experienced English chronometer maker. The indicator is attached to the cycle by means of a strong clamp fastening on the front fork, just below the crown. The mechanism comprises a miniature centrifugal fan, revolving m an air-tight compartment. The air pressure created impinges on a small arm like a ■windmill sail, which is free to revolve and turn a pointer on an indicating dial, showing the various speeds, according to the velocity of the fan. Between the windmill arm and the pointer intervenes a fine hair spring, fitted on an eccentric cam, by which its pressure is raised to bring the pointer back to normal, as the speed of the fan is varied by the speed of the road wheel. The transmission is by friction pulley, which is held m contact with the rim of the road wheel by suitable clips, and thence by encased flexible shaft to indicator, which may be clipped in any convenient position to the handle bar.