GB233205A - Improved apparatus for testing hardness by impact - Google Patents

Abstract

233,205. Haas, A. L. July 31, 1924. Testing hardness of materials.-The force of the blow on the test ball or cone producing the indentation is obtained from a spherical or cylindrical weight falling freely by gravity from a known height, which may be varied. A spherical weight impinges directly on the test ball in contact with the specimen, but in the case of a cylindrical weight the ball is preferably housed on the underside of the weight. A tubular casing enclosing the spherical weight M may be in one length, but is preferably in sections A, A, telescopic by means of bayonet connections B, C. The test ball U is housed between diaphragms R, T having slots through which projects screws P fixed on a ring 0 and folding rigid a diaphragm N having a hole Q in the centre through which the test ball projects to receive the blow from the weight M, which is held up in position by an oval garter spring K which is deformed to a circular shape by hand to release the weight. The top of the casing is enclosed by an annular washer H, an indiarubber washer I, and a diaphragm D rigid with the casing by screws F and carrying a spirit level G. The weight is re-positioned for a further test by merely inverting the apparatus. Fig. 4 shows the test ball U housed by a plate 2 on the underside of a cylindrical weight V. In a modified means for releasing the weight horizontal wing-shaped members project through slots in the casing and through corresponding slots in a cylinder surrounding the casing and revoluable thereon, rotating of this cylinder withdrawing the wing-shaped members against spring pressure to release the weight.