GB584246A - Improvements in or relating to machines for measuring the hardness of metals or other materials - Google Patents

Abstract

584,246. Testing hardness of materials. BOLLEE, P., and BOLLEE, M. Jan. 25, 1940, No. 1544. Convention date, Oct. 20, 1939. [Class 106 (ii)] The indentor is carried on a bracket or arm which is depressed when the specimen lying on a table is moved against it, dial indicators separately supported from the base engaging by their plungers the table and bracket respectively, and the difference of their readings giving the indentation. A plate 6 on which the specimen rests bears upon the upper end of a screw 8 through which a shank fixed to the table passes and bears at the lower end against an eccentric moved by a handle 10 frictionally engaging a sector 11. The screw is raised and lowered by a rotatable nut 12 which forms a rough adjustment while the eccentric operated by the handle 10 gives the fine adjustment. The indentor 3 is carried by a bent arm 1 which is solid or comprises blade springs, rigidly mounted on the base 2 of the machine. Pillars 15, 16 rising from the base have slidably adjustable thereon arms 19, 20 carrying dial indicators 17, 18. The plunger of the indicator 17 engages an adjustable screw 22 on a lug 21 on the arm 1, while the plunger of the indicator 18 engages a screw 23 on the table 6. In use, the specimen and table are raised by the screw 8 until the needle of indicator 17 moves, the screw 23 already contacting the plunger of indicator 18. The two indicators are now zeroized and the specimen moved further by using the handle 10 and eccentric until the needle of 17 indicates the required pressure. The handle 10 is now moved to lower the specimen until the indicator 17 reads zero. The reading of indicator 18 lags behind by an amount representing the depth of the impression. By mounting the indicator 18 on the arm 1, the test may be carried out by measuring the load to give a standard depth of impression. The arm 1 may be detachably mounted and others substituted for it. The Specification as open to inspection under Sect. 91 comprises also a modification wherein the arm is mounted on a sliding carriage mounted on a second carriage moving at right angles. This machine is also equipped for friction tests. The penetrating member may have substituted for it a rubbing member for wear tests, and the table be replaced by a rubbing table. An electrical pick-up including a lamp circuit detects the alteration in the rubbing surfaces due to seizing &c. The table may be raised automatically to compensate for wear on the specimen. Surface finish of specimens may be tested by the pick-up device. This subject-matter does not appear in the Specification as accepted.