GB1521980A - Speedometer and odometer apparatus - Google Patents

Abstract

1521980 Speedometers JAEGER 30 Dec 1975 [30 Dec 1974] 53189/75 Heading G1K A speedometer and odometer instrument comprises a drive input shaft 1, an eddy current speedometer mechanism 6-10, and an odometer assembly including main and trip odometers 25, 29, Fig. 10, and a zero resetting means 34-39, Fig. 3, for the trip odometer, the components being mounted in a frame comprising two separable parts 2, 5, the lower part 2 carrying the drive input shaft 1 and the upper part 5 enclosing the odometer assembly, with the speedometer mechanism held between the two frame parts. The speedometer comprises a disc magnet 6 secured to the input shaft 1 to rotate within a drag cup 8 secured to a pointer shaft 10. A spiral spring 45 resists rotation of the cup 8 when the magnet 6 is rotated, and is connected to the shaft 10 by a collar 46 which extends into a cup 47 of the frame 5 containing a damping liquid. The outer end of the spring 45 is secured to the frame 5 by a peg 48. A yoke 13, Figs. 1 and 4, surrounding the drag cup 8 carries a resilient bar 12 which passes below a raised cross-bar portion 14 of the yoke 13. The shaft 24 of the main odometer 25 is driven from a gear 67 integral with the input shaft 1 via a shaft 21, Fig. 6, and a shaft 22, Fig. 9. Resilient combs 33, Fig. 10, bear on the number wheels of the odometers to resist rotation thereof. To prevent reverse drive of the odometers, the shaft 21 is axially movable so that when the input shaft 1 rotates in a reverse direction the shaft 21 moves against a return spring 41 to disengage a worm 40 on the shaft 21 from a worm wheel on the shaft 22. The shafts 24, 31 of odometers 25, 29 are coupled together by gears 26, 27, 30. The trip odometer reset mechanism, Fig. 3, comprises a shaft 34 axially movable against a spring 36 to bring a gear 38 thereon into mesh with a gear 39 on the odometer shaft 31.