GB467276A - Improvements in or relating to apparatus for testing the hardness of materials - Google Patents

Abstract

467,276. Testing hardness of materials. RULE, J., and HOLMAN BROS., Ltd. Dec. 27, 1935, No. 35882. [Class 106 (ii)] Comprises opposed members for bearing a workpiece under test, a C-shaped spring support for the members, and means to stress the support and thereby load the members to produce indentation of the workpiece in combination with means for indicating the consequent relative movement of the end parts of the support. The extremities 2, 3 of a stiff C- spring 1 are extended into parallel arms 4, 5 of which the former carries a dial gauge 8, the plunger 12 of which is adapted to engage an adjustable screw 49 carried by the latter. The arm 5 is in one with a bracket forming a guide 16 for an anvil 17, the other guide 18 for which is formed on the inner end of a handle 19 fixed to the spring. The anvil is guided by a sleeve 21 on a bolt through a slot in which the spring 1 passes. Diametrically opposite the anvil a bracket 27 is clamped to the spring. This bracket carries a strut 26 with indenting ball 48, and also the pivot pin 30 of a lever 32 which pin has formed on it an eccentric or cam 31 engaging a recess in the spring 1. A link 36 pivoted to handle 19 has a notch which engages over a pin 35 on the lever 32. In use, the specimen 25, a rock drill, is placed in the anvil and the dial indicator brought to zero by manipulating the screw 49. The small lever 41 is then grasped to turn. the plate 38, a pin on which knocks out the link 36 releasing the lever 32 which is moved down until abutment 24 engages the abutment 33. This movement turns the eccentric and in effect lengthens the strut 26 forcing the ball into the specimen and separating the jaws 4, 5 thus causing the dial indicator to operate. Fixed pointers 54, 55 may be set at desirable limits of hardness.