GB559143A - Improvements relating to devices for gauging dimensions - Google Patents

Abstract

559,143. Linear dimension gauges. WILKINSON, S., and GREEN, A. April 16, 1943, No. 6782/42. [Class 106 (ii)] A linear-dimension gauge of the kind comprising a pair of gauging members, one of which is movable, indicating means, and motion magnifying means whereby a small change in the dimension of the article to be tested is readily measured and observed, is characterized in that a lost motion connection is provided between the movable gauging member and the indicating means, means being provided for adjusting the position of the movable gauging member relative to the gauge at which said lost motion is taken up and movement transmitted from the gauging member to said indicating means, whereby irrespective of variations in the dimension to be tested, motion may be transmitted to said indicating means only when the movable gauging member approaches the surface of the article to be tested. A calliper gauge has a primary gauging member 51 slidable in a tubular body 10, the outer end of which is stepped as at 15 and closed by a cap 17 held in place by a flanged tubular member 21, the thread 22 of which engages the incomplete thread 16 of body 10. The end of the slide 51 abuts against an adjustable screw 68 in a push button 60 slidable in the member 21 and having a screw engagement with the split portion 54 of a collar 52, frictionally adjustable on the slide 51. A pin 56 projects from the collar 52 through a slot in a plate 31, secured to the body, and acts on a lever 37 which actuates a lever 35 of spring metal having its end fixed in a groove 34, so that when the lost motion existing between the pin 56 and the lever 37 has been taken up by movement of the button 60, any further movement of the pin 56 is greatly magnified on a scale 42. Adjustable clips 46 may indicate permissible tolerance. In use, members 21 and 26 are unscrewed to allow adjustment of the collar 52 along the slide 51, and are then replaced. A secondary gauging member 64 is adjusted until with the test piece in position and the push-button 60 pressed in, the needle indicates zero. Variation from standard of subsequent articles are shown on the scale. The device may be adapted, Fig. 2 (not shown), for use as a depth gauge, a second scale 45 being provided with plus and minus reversed. In a modification, Fig. 8 (not shown), the member 64 is replaced by an ordinary micrometer gauge, the scale being modified in this case to read from 0 to 10. In a further modification, Fig. 9 and Fig. 10 (not shown), the body 10 is secured to a micrometer shank, the slide 51 passing through. In use, the body 10 is turned until the micrometer has been set with a line 78 exactly opposite a whole scale division 77. Operation of the button 60 then gives the equivalent of a vernier reading.