GB329629A - Improvements in or relating to means for measuring the hardness and thickness of objects - Google Patents

Abstract

329,629. Daynes, H. A., Johnson, E. B., and Research Association of British Rubber Manufacturers. Feb. 18, 1929. Testing hardness of material, linear-dimension gauges.-Comprise an indenting member applied to the specimen under a fixed load, and an area near the point of indentation, a rigid contacting surface of another member simultaneously applied, a mea.surment being made of the displacement of the indenting member relative to the contacting member. A base 1 fitted with three feet 2 is provided with two vertical posts 5 located one behind each other on the centre line of the base. Sliding on the base 1 is a dial gauge 6 the pointer of which is actuated by a stem 8 projecting above and below the casing. The top of the stem terminates in a knob 9 while the bottom terminates in an indenting member 10 which may be formed separately and screwed to the stem on which is removably supported a weight platform 13. The platform balances the spring when the stem is depressed correspondingly to an indentation of 1 m.m. A spring 17 holds the case in adjusted position, forked lugs on the back of the case embracing the other pillar to prevent rotation about the pillar. A foot 19 secured to the casing surrounds the indenting member 10. To use the device it is placed on a glass plate and the casing moved down until the foot 19 engages a glass plate. A reading is taken or the scale zeroized. The gauge is then raised and the rubber disc 4 laid on the glass plate. The gauge is again lowered into contact and the platform 13 loaded. The difference in the readings is indentation depths. For use with cylindrical surfaces such as those of rubber covered rollers, the base has machined in it four V-shaped parallel grooves 21 parallel also to the centre line. Cylindrical rods 22 are secured in two symmetrically arranged grooves and the device applied first to a standard roller. It is then applied to the roller to be tested and loaded. The casing of the gauge is formed with a boss 28 and the loading platform 13 may be removed and a 'supporting member 27 mounted rigidly on the boss. The gauge is then raised and supported in the raised position by a pin 26 placed through a lower hole 5<a> formed in the front post 5 which pin is normally in a hole in the upper part of the post. A removable member 30 having contact tees 31 is placed on top of the gauge stem 8 and the device may then be used to gauge thicknesses of rubber &c. rings in the same manner as described in Specification 324,504.