GB1189480A - Improvements in or relating to Speedometers - Google Patents

Abstract

1,189,480. Speed-responsive switches. C.N.M. ROUNTREE. 22 July, 1968 [8 Aug., 1967], No. 36471/67. Heading H1N. [Also in Division G1] A speedometer includes means, enabling a signal to be given when a predetermined speed is reached, which comprise a transparent plate 1 replacing its usual cover glass and, between the dial and plate 1, a pointer 2 which is coupled to an external setting knob 7 and carries contacts 8 arranged to be pressed together or bridged by the speed indicator 12 or by a contact 13 carried thereby when the set speed is indicated. The contact 13 may be as long as a portion of the scale representing 5 m.p.h. With an arcuate scale on a rectangular dial, Fig. 1, the pointer is guided for manipulation over the scale by slots 4, 5 in the plate 1 cooperating with a pin or cam 6 on the pointer 2 and a threaded stud extending upwardly therefrom on to which the knob 7 can be screwed so that it can be clamped and unclamped. Connected to the contacts 8 on its under surface, the pointer 2 carries contacts 9 on its upper surface to sweep arcuate conducting strips 10 on the under surface of the plate 1 which are connected through terminals 11 to a source of power and a warning device, which may be visual, audible or both. Modifications to suit speedometers with linear scales and tape indicators and with circular dials are described with reference to Figs. 2 and 3 (not shown). A vehicle driver may set the pointer 2 upon entering a new speed restricted zone and a switch may be provided for inhibiting the warning device in unrestricted areas. The contacts 8 may be metal rollers embedded in the pointer 2 or metal strips projecting from the pointer 2 towards the dial and slightly curved convexly towards one another.