GB708566A - Apparatus for indicating the average speed of a vehicle - Google Patents

Abstract

708,566. Speedometers. LINDHOLM, N. G. H., and JUSELIUS, S. O. Dec. 11, 1951 [Dec. 19, 1950], No. 29015/51. Class 106 (3) An apparatus for indicating the average speed of travel of a vehicle comprises in combination, a time clock 6, Fig. 1, including a clockwork, dial and hands 5, 5<SP>1</SP>, a separate pointer 7 mounted for rotation in front of said dial concentrically with the hands of the clock but independently of the clockwork, a transmission for imparting a clockwise rotation to said separate pointer in response to the speed of travel of the vehicle, a change speed mechanism included in said transmission for causing the transmission to rotate the said separate pointer 7 at the same angular velocity as one hand of the clock, when the vehicle is travelling at a given average speed. A shaft 1 rotated at the vehicle speed is cranked at 8 to close once per revolution a switch 9 and so energize an electromagnet 11 the armature 13 of which is moved to the 'left against the pressure of a spring 12. The armature 13 is connected to a lever 17, Fig. 2, pivoted on a shaft 4 and the lever 17 transmits movement to the shaft 4 through a roller 20 located between a flange 21 of the lever 17 and the periphery of a wheel 18 fixed to the shaft 4. A spring 19 urges the roller 20 to abut the flange 21 and the wheel 18. In the return movement of the levers 13, 17 no movement is imparted to the wheel 18 which is locked by a spring-loaded roller 22 located between the periphery of the wheel 18 and a sloping member 23. The stroke of the armature 13 is determined by two steps 15, 16, Fig. 1, one of which is adjustable so that pointer 7 may be made to rotate with the minute hand 5 for any particular vehicle speed. In another embodiment, Fig. 4, the lever 17 is moved by an eccentric 24 on the shaft 1 and the stops 15, 16 are replaced by cams 26, 27 which co-operate with the end 25 of the lever 17. The cam 27 is rotatable to vary the movement of the lever 17. The cam 27 is carried by a drum 28 having a speed scale and a logarithmic distance scale which co-operates with a logarithmic time scale on an adjacent drum 37. The pointer 7 is initially set by a knob 33 through gears 35, 36, 31, 32. If desired, Fig. 5 (not shown), the cam 27 may be replaced by a travelling band which is fed between two rollers at a rate porportional to the speed of the vehicle and which is shaped to automatically vary the movement of the lever 17 in accordance with different desired average vehicle speeds.