Patent GB-785782-A (GB)
Title: Improvements in or relating to dial gauges for measuring differences in dimensions
IPC: G01B3/22
Filed: 1956-05-14
Abstract: 785,782. Dial gauges. DROZ, R., and MEYER, H. May 14, 1956 [May 17, 1955], No. 14929/56. Class 106 (2). [Also in Group XXXVIII] A linear dimension dial type gauge has two co-operating smooth tracked rolling bodies, and movement of the feeler of the gauge causes a change in the hinge spacings of-these bodies with a resulting swinging movement thereof, there being means for ensuring a positive relative movement of the rolling bodies. The feeler 41 of the dial gauge shown in Fig. 1 acts on one arm of a lever 17 pivoted at 18, the other arm of the lever carrying a pivot 16 on which a body 5 is mounted, the body 5 having a surface 7 that is an arc of radius R<SP>2</SP> from a centre displaced by an amount e from the pivot 16. The surface of the body 5 rolls against a surface 6 of a body 4 mounted on a fixed pivot 8, the surface 6 being on an arc of radius R<SP>1</SP> with its centre at the pivot 8. A positive relative movement between the arcuate surfaces 6 and 7 is ensured by bands 29 and 30, Fig. 3, that are disposed in grooves in the arcuate surfaces 6 and 7 and couple the bodies 4 and 5 together such that the bands 29 and 30 cross at the point of contact of the surfaces 6 and 7. A toothed segment 20, secured to the body 4, actuates a toothed pinion 21 carrying a pointer, the pinion 21 being rotatable against the action of a helical spring. In operation, when the feeler 41 is depressed against a spring 37, the lever 17 is turned anticlockwise and causes the pivot 16 to move away from the pivot 8. The arcuate surfaces 6 and 7 therefore tend to move apart but since this is not possible, by virtue of the interconnecting bands 29 and 30, the body 5 is forced to turn anticlockwise about its pivot 16 so as to move its centre of curvature towards the fixed pivot 8. The necessary turning movement is transmitted to the pointer via the body 4, toothed segment 20 and pinion 21. In a modification the toothed segment 20 and pinion 21 are not used, the indicating. pointer being mounted on a roller disposed between the arcuate surfaces 6 and 7. Alternative embodiment. In Fig. 6, the body 64 is mounted on a pivot 71 carried by the feeler 68, the body 64 having a surface that is an arc with the pivot 71 as its centre. The body 63 is mounted on a fixed pivot 65 and has a surface 77 that is an arc with its centre at some point below the pivot 65. A positive relative movement between the arcuate surfaces 76 and 77 is ensured by toothed segments 74 and 75 secured thereto by screws. When the feeler 68 is pressed into the dial gauge the pivot 71 is moved towards the fixed pivot 65 with the result that the body 63 turns clockwise, moving the eccentric centre of curvature of its arcuate surface 77 to the left. The amount of turning movement of the body 63 may be measured electrically by a resistance 82, Fig. 8, associated with the arcuate surface 77 pressing against a co-operating contact member on the arcuate surface 76. Both bodies may be provided with resistances. It is also possible to provide at least one of the bodies with one or more contacts which are operated successively as the bodies rotate.