GB610585A - Improvements in or relating to linear-dimension gauges - Google Patents

Abstract

610,585. Linear-dimension gauges; indicating- apparatus. SIGMA INSTRUMENT CO., Ltd., and BOOSEY, F. R. April 10, 1946, No. 11070. [Classes 106 (ii) and 106 (iv)] The indicating-apparatus of a comparator or other linear-dimension gauge has two pointers 15, 24 of different sensitivity actuated by a lever 8 pivotally mounted on axis 9, 9 and provided with a knife-edge disc 7 in contact with a member 6 secured to a plunger 5 which is in contact with the feeler 2 of the gauge, the pointer 24 indicating to an enlarged scale a small selected range of movement of the pivoted lover 8. The free end of lever 8 contacts a knife-edge member 16 adjustably carried by a cam disc 17 rotatable about axis 19, 19. A strap 20 secured to and passing around the cam 17 is secured to the free end of a leaf spring 21 which tends to turn the cam about its axis so that member 16 follows the free end of lever 8. The pointer 24 is secured to the cam 17. The pointer 15 is connected to a point between the free end and pivot of the lever 8 and follows all movements of the latter: the pointer 24 is actuated only during the time the member 16 engages the free end of the lever 8. Springs 11, 13 maintain the disc 7 in engagement with the member 6. To facilitate zero adjustment of the pointers, the lover 8 is pivoted in a bar 30 which can be flexed by a rod 32 adapted to be moved by rotation of a screw 33. By passing the band 20 around the cam 17, the varying pressure exerted by the deflected leaf spring 21 is compensated, so that there is a substantially constant pressure between member 16 and lever 8.