GB873386A - - Google Patents

Abstract

873,386. Balancing speedometer drag-cups. GENERAL MOTORS CORPORATION. Nov. 27, 1958 [Dec. 6, 1957], No. 38294/58. Classes 106 (2) and 106 (3). Holes are punched in the drag-cups of eddycurrent speedometers in order to balance them about their rotational axes. Drag-cups 12 are mounted with their shafts 14 horizontally supported on circumferentially spaced pairs of radially aligned bearings spaced around a turntable 28; one or both of each pair of bearings is vibrated to assist the cup 12 to turn about its axis and come to rest with its centre of gravity vertically below the shaft. Three punching stations 72, 74, 76 are spaced around the turntable 28. Each station has an overhead arm 78 to which respective V-shaped cams 80, 82, 84 are attached. Each pair of bearings has associated with it two cam followers 54 and 70, cam follower 54 being associated with punch 40 (Fig. 6) and cam follower 70 with a second punch (not shown). Punch 40 is mounted in such a position relative to the bearings that it punches a hole 62 (position II in Fig. 10) on a radius angularly displaced from the vertical through the axis of the cup 12. The second punch is mounted so that it punches a hole 88 (position VI in Fig. 10) vertically below the axis. When the turntable rotates, first cam follower 54 follows cam 80 and actuates punch 40 (to punch hole 62), at the second station cam follower 54 is moved by cam 82 and actuates punch 40 again to punch a hole 86, Fig. 10, and finally cam follower 70 is moved by cam 84 to actuate the second punch. In between the punching stations the cup turns about its axis assisted by the vibrating bearings so that its new centre of gravity is below the axis. Holes 62, 86, 88 are punched as a result in the positions shown in Fig. 10. Since the distance of the original centre of gravity from the axis due to manufacturing tolerances lies within certain known limits, the weight removed by the punching operations can be arranged so that the equilibrium position of the cup 14 after the first two operations is such that the original centre of gravity is substantially above the axis (see position V, Fig. 10) and the new centre of gravity is on the opposite side of the axis from the old one and considerably nearer to the axis. The final punch 88 moves the new centre of gravity nearer still to the axis.