GB760828A - Improvements in or relating to hardness testing instruments - Google Patents

Abstract

760,828. Hardness testers; gauges. DEAKIN, J. 0., [trading as DEAKIN & CO., J. 0.]. Feb. 2, 1955 [Feb. 2, 1954], No. 3087/54. Class 106 (2). A hardness testing instrument comprises a diamond 1, Fig. 1, a retractable mount 1a for the diamond and a spring 14 permitting retraction of the mount 1a under a predetermined minimum load together with a gauge 10 and a direct mechanical linkage between the gauge and the mount. The mount 1a is pressed into a sleeve 3 sliding against the spring 14 rated at fifteen pounds in an outer sleeve 4. The linkage comprises a steel ball 4a supporting a push-rod 6 in turn supporting at its upper end a block 7 abutting a second ball on which rests the lower end member 8 of the gauge 10. Movement of the member 8 is transmitted to a pivoted lever 31, Fig. 6, causing increment of a block 33 secured to a sliding rack whose teeth 38 engage the first pinion 39 of gearing 39, 40, 42, 43, driving the needle spindle 44. A spring- loaded back-lash wheel 45 also engages the pinion 43. A collar 17 loaded with a five pound spring 18 and sliding on the outer sleeve 4 forms a base and the instrument is operated by a press-member 24 secured to a collar 21 loaded with a thirty pound spring 22 to slide on a sleeve 20 secured to the sleeve 4.