GB595016A - Improvements in and relating to micrometer screw devices - Google Patents

Abstract

595,016. Gauging-devices. MOORE & WRIGHT (SHEFFIELD), Ltd., and MORRISON, A. E. March 28, 1945, No. 7827. [Class 83 (iii)] [Also in Group XIX] A micrometer device has a screw-threaded spindle which is rotated by means of a drum provided with Braille graduations on its periphery which co-operate with a datum mark, perceptible by touch, on a stationary member adjacent to the drum. In a machine tool slide, a base 51 carries a slide 54 which is engaged and traversed by a nut 55 on a feed screw 50, on which are mounted three drums 16, 17, 18. The drum 18 is secured to the screw 50 and the drum 17 is held against rotation by means of a bracket 52. The drums 16 and 17 have toothed inner peripheries engaged by two planet wheels carried by a spindle mounted in a bearing formed as a radial extension of a sleeve secured to the screw 50 and, in this manner, the drum 16 is caused to rotate, for example, one-fortieth of a revolution for each complete revolution of the drum 18. Raised graduations on the peripheries of the drums 16 and 18, on which the zero marks are preferably raised lines, cooperate with a raised datum line on the centre stationary drum 17, which is also provided with a set of vernier graduations. The drums 16 and 18 have forty and twenty-five graduations indicated by Braille characters respectively, those on the drum 16 being indicated in ten groups of four and those on the drum 18 in five groups of five. A micrometer and a micrometer comparator (see Group XIX) incorporating the device are also described.