GB687434A - Improvements in or relating to hardness tester - Google Patents

Abstract

687,434. Testing hardness of metals. AMERICAN PULLEY CO. Sept. 25, 1950, No. 23424/50. Class 106 (ii). A device for testing the hardness of magnetizable metals comprises a magnet, for attachment to the test specimen S<SP>2</SP>, in which is held an adjusting element 25a connected by a spring element 29a to a penetrator 19a. The load applied is indicated by a gauge 38a actuated through flexure of the spring element, and the depth of penetration indicated by means 42a, 46a operated through movement of the element 25a. As shown, a permanent horseshoe magnet 10a, bifurcated at 60 so as to have three-point contact with the specimen S<SP>2</SP>, has a central bore in which is secured a non-magnetic tube 62. The element 25a is screw-threaded in the tube and carries a hand wheel 28a with a sleeve extension 67 on which is adjustably held by a spring-urged ball 68 the graduated indication collar 42a which co-acts with a mark 46a on a fixed transparent member 41a. In operation, the wheel 28a is rotated to bring the penetrator 19a into contact with the specimen until the gauge pointer registers " Set." The collar 42a is rotated to the zero position and the wheel is further rotated until the indicated load is 15, 30 or 45 Kg. The wheel is then turned back until the gauge pointer again registers " Set," when the collar 42a will indicate the penetration depth. After the test, the magnet 10a may be forced away from the specimen by screws such as 78 engaged in non-magnetic straps 75 secured to the inner surface of the magnet. Alternatively, an electromagnet may be used, the screws and straps then being unnecessary.