GB160963A - Improvements in or relating to speedometers - Google Patents

Abstract

160,963. Speigrht, A. Jan. 8, 1920. Periodic-counter speed indicators.-Relates to apparatus driven through an epicyclic gear, and consists in a gear comprising a pair of sun-wheels of slightly different diameters. On a shaft D slotted to receive a flexible lead is mounted a carrier arm E with planet pinions e<1>, e turning in one with each other on a pin e<2>, and gearing with sun wheels F, G, the wheel G having about one tooth more than the wheel F, on sleeves f, g, respectively. The sleeve g carries a ratchet-wheel L, and to the sleeve f is fixed a returning-spring h<1>, and a disc H with a driving-pin engaging a spring-pressed pin j on a ratchet-disc J attached to a pointer K and a return spring j<1>. The wheels L, J, are freed by pawls actuated from cams N, N<1>, driven from a clock B. In operation, if the sun-wheel G is held by the cam N<1> and ratchet L, the drive from the shaft D is transmitted to the wheel F and thence to the pin h and pointer K, until at the end of a predetermined time the disc J is freed by the cam N and turned back, in the event of falling speed, by the spring j<1>; the wheel L is then freed, the epicyclic gear thus being rendered ineffective, and the wheel F is returned to its zero position by the spring h<1>, the disc j and the pointer K remaining at their maximum reading. The spring-pressed pin prevents the pointer K from indicating in the event of a reversal of motion of the shaft D.