Apparatus for measuring the hardness properties of materials

Improved apparatus for measuring the hardness properties of materials comprising a frame for supporting said apparatus and the material to be tested;

• a tester head assembly mounted on said frame for applying predetermined measuring forces to said material and a clamp assembly mounted on said frame for supporting said material and for applying a clamping force to clamp said material against said tester head assembly prior to said application of said predetermined measuring forces;
• said tester head assembly including housing means attached to said frame;
• a penetrator assembly carried by said housing, including an axially reciprocal penetrator shaft at the lower end of which is a penetrator member for contact with said material;
• operating means for applying a first predetermined force and a second and greater predetermined force to said penetrator shaft for indentation of said material by said penetrator member and means for measuring the difference of indentation of said material by said first and second predetermined forces;
• wherein the improvement comprises:
• an electronic load cell for measuring said first and second predetermined forces attached between and connecting a first shaft portion, being the lower end of said penetrator shaft, and a second shaft portion, being the upper end of said penetrator shaft;
• said housing means comprising a lower housing portion in which said penetrator shaft is carried, an intermediate housing portion and an upper housing portion, said operating means including first and second piston members carried in said upper and intermediate housing portions, respectively, and responsive to fluid pressures applied thereto for applying said first and second predetermined forces to said penetrator shaft.