GB561168A - Improvements in or relating to mechanism for controlling the movement of the indicator needle of a dial gauge - Google Patents

Abstract

561,168. Dial gauges. WOODALL, F. J. Sept. 14, 1942, No. 12932. [Classes 106 (ii) and 106 (iv)] The needle of a dial gauge is controlled by means of a pivoted abutment member or cam associated with the needle and a pin element carried by the displaceable element of the gauge, the needle and pin element having springs which act to press the pin element against a contact face of the abutment member. As shown in Fig. 1, the casing 1, which is adapted for attachment to the swinging arm of a stand, has a depending part 9 housing a sleeve 8 formed with cheeks 11, Figs. 3 and 4, through which pass bearing pins 12 engaging bosses in the end flanges 14 of a semicircular cam-shaft 15. Mounted on one of the bosses is an indicating needle 7 to which is attached one end of a control spring 18. The needle 7 is formed with an arcuate slot 22 in which is a set screw to limit the movement. The plunger 26, Figs. 4 and 7, which is to engage the workpiece is formed at its upper end with a bracket 25 which carries an adjustable bush 24 with a pin 23 engaging the cam 15. The upward movement of the plunger acts against a tension spring 30 that is stronger than the spring 18. In the upward movement the pin 23 will free the cam 15 which will follow under the action of the loading spring 18. In a downward movement of the plunger, the pin 23 will cause the cam 15 to rotate in the opposite direction. In a modified form, Fig. 10, the indicating needle is mounted on a spigot pin 34 and carries a pin 36 (not shown) for co-operation with the edge 37 of a lever arm 38 connected to the cam-shaft 15. The lower end of the engaging pin 23 may be formed with a blade edge instead of a point.