GB600847A - Improvements in or relating to micrometers - Google Patents

Abstract

600,847. Micrometer gauges. GILMORE, G. E. H. Jan. 15, 1946, No. 1329. [Class 106 (ii)] A micrometer gauge, having means whereby the setting of the gauge to a definite position according to an " inches " scale will permit the corresponding metric measurement to be read off, is characterised by having its thimble geared to an adjoining thimble rotatably mounted on a second sleeve secured to the frame. The two sleeves H and M<1> are secured to a frame A and co-operate with rotatable thimbles G and M which are connected by means of gearing G of suitable ratio. The primary sleeve and thimble Hand G control the micrometer spindle F and are calibrated in English measure, while the auxiliary sleeve and thimble are calibrated in metric units. The micrometer anvil B may be secured with a set - screw E to the frame A, in any of four positions determined by lugs B', one of which is held against the inner face of the frame A by a spring D. The lugs B<1> are spaced one inch apart and for this reason, the metric sleeve has four longitudinal scales-from 0-25 mm., 25-50 mm., 50-75 mm. and 75- 100 mm.-each scale being spaced 0.4 of the circumference of the sleeve from the consecutive scale and being longitudinally displaced by 0.4 mm., since 25.4 mm. equal one inch. Each longitudinal scale line on this sleeve is doubled to act as a simple vernier. Means for taking up wear (not described) may be employed and a locking-nut for the spindle F is provided which acts on the frame A, the latter being split to form two eccentric semi-circular flanges which are relatively moved by rotation of the locking-nut to clamp the spindle.