GB277855A - Improvements in a pendulum hardness tester - Google Patents

Abstract

277,855. Leeson, E. von. Jan. 17, 1927. Testing hardness of materials-Relates to apparatus of the type in which a pivoted pendulum hammer in rebounding from a fall against the specimen pushes a pointer over a scale to indicate the hardness, and consists in providing a spirit level perpendicular to the front wall of the device, or parallel to the direction of movement of the hammer at the instant of rebound, in order that the indicating apparatus may be correctly set up. The spirit level 2 is lodged in a block 4 cast on the case 3. The hand or pointer 5 passes under a stretched wire 6 and over the scale 5a rubbing against both sufficiently to be frictionally held in any position. The hammer is adapted to swing through an aperture 12 in the casing, and two prismatic grooves 14, 15 at right angles cross each other in the centre of the aperture for the purpose of centering the curved surface of a specimen in order to secure a radial rebound of the hammer. A protecting flap 19 covered with felt to keep dust out of the casing is secured to a spindle 23 turned by a milled head 24 when withdrawn from the slot 17 against the influence of a spring 25. The hammer, is returned to the highest position by moving a milled head at the back of the case to turn a stud 29 on which is a disc 31 carrying an arm 30 with a bent end 30<a> adopted to engage the hammer rod 36. The disc is connected to the casing by a spiral spring. The needle 5 is returned to zero by a spring lever. The pendulum is locked after use by a U-shaped lever 27. The hammer is released for a test by the spring latch 27a.