Measuring head for hardness testing machine - has force pick-up and displacement pick-up for height independent differential measurement

摘要

The measuring head has a removable point or ball for penetration of the test-piece whose hardness is to be measured. The head is fixed on a force mechanism which applies a load causing the penetration of the point or ball into the test piece. A displacement pick-up and force pick-up (8) are connected to a calculator for obtaining directly the hardness value. The displacement pick-up has the means for differential measurement which makes it independent of the height of the test piece. The differential measurement is made by contact points mounted in a flexible manner on the measuring head, and directly connected to the feeler of the displacement pick-up whose body is fixed on the head. The force pick-up is found on the upper part of the head, the effort exerted by the force mechanism being applied on it. The force pick-up is connected by peripheral columns to a base plate on the lower face of which is found the penetrating point or ball. The displacement pick-up body is fixed on an intermediary plate positioned on the columns.