Patent GB-417881-A (GB)
Title: Improvements in or relating to a method of and apparatus for testing individual bodies to determine the hardness or bending characteristics thereof or comparing said characteristics with those of a standard body
IPC: G01N3/42
Filed: 1933-04-28
Abstract: 417,881. Testing physical qualities of material. GOGAN, J., 13870, Clifton Boulevard, Lakewood, Ohio, U.S.A. April 28, 1933, No. 12448. [Class 106 (ii).] The hardness or bending characteristics are tested by pressing a member into the material and/or against a surface thereof by an automatically increasing force, the intensity of which is at all times determined or regulated solely by the resistance of the material to the movement of the member, and measuring the distance through which the member has moved when said force reaches a predetermined maximum value. A frame 10 having a base 11 and head 12 is reinforced by two heavy ribs 13 and is mounted on a bed. The work 14 is placed on an anvil 17 mounted on a screw 16 fitted with a clamping unit 18. The penetrator 2 2 which may be a hardened ball or a diamond is carried by a chuck 24 supported in a holder 23 slidable on guideways 25. At the upper end of the head 12 is a cylinder 26 in which is a piston 27 connected with the holder 23 by a hollow rod 28 housing a spring 29 the lower end of which engages an abutment 30 carried by a cross pin 31 secured to the head and passing through slots in the sides of the rod 28. An inlet port 34 admits pressure fluid, for instance oil. Supply of pressure fluid. A motor 38 drives a rotary pump 37 which through a pipe 40 draws oil from a reservoir 39 and discharges it through pipes 41, 42 into a chamber 45 controlled by a spring-pressed valve 46 which normally allows the oil to be byepassed through a passage 47 to the reservoir. Upon depressing the pedal 49 the plunger 46 closes the opening 51 and oil is forced through pipes 58, 59, 36 to the cylinder 26. A pressure regulating valve 60 on the pipe 59 byepasses the oil to the reservoir 39 when a predetermined pressure is attained. The pressure of the spring 68 which acts on the valve 62 may be adjusted by a screw 71. The valve has a reduced portion 72 and below this a head 73 having longitudinal grooves in the edge so that when maximum pressure is reached the oil passes through the grooves and reduced portion into the chamber 65 and back to the reservoir. The pipe 59 also is fitted with an accumulator comprising a piston 100 located in a cylinder 98 and acted upon by three nested springs 101, 102, 103. Depth gauge. A dial indicator 75 is adapted to be actuated by a member 77 of magnetic material releasably connected to the holder 23. The latter is moved down rapidly until the workpiece 14 is engaged by the indentor 22. At this point the spring 29 has been compressed to such an extent that the pressure in the pipe 59 starts to move piston 100 which steadies the load and causes the speed of holder 23 to slow down. The spring acting upon an electric contact 92 is such that the contact 92 is moved to engage a contact 96 just when the penetrator engages the work. The circuit of an electromagnet 78 is then made and the actuator 7 clamped to the holder 23. The subsequent movement of the holder indicated by the gauge 75 is the depth of penetration. In a modification, the actuator for the indicator is frictionally clamped by a spring against which it is retracted by an electromagnet. In a further modification, the actuating member is releasably connected to the holder by a fluid pressure arrangement. A gauge 104 indicates the maximum load and a drain pipe 105 directs fluid leaking past the piston back to the reservoir. In a form shown in Fig. 8, the screw 23 carries a work holder 20 having a mandrel 22 adapted to receive a hollow work piece such as a wheel hub 25 the mandrel carrying a steel support 32 and a ball indentor 30. The load is applied by a member 33 slightly offset from the penetrator towards the button 32. A combined deflection and hardness test is thus made. In a further modification a bending test may be made on an axle by using a part 29 with a flat end engaging the top face of the axle which is carried in two supports spaced apart.