Rubber pad

The circular rubber pad.

The circular rubber pad is the oldest form of bonded rubber spring. In design it is characterised by the diameter and the height. In practice it is given the name of “metalatic” pad mounting. Its range of application is very large. There are manufacturer who make circular rubber pad in over 100 different size and each in five different rubber grade for loading ranges up to 100 kN per rubber spring. In the moulding process the rubber pad are bonded to adjoining metal insert etc. Some design the rubber pad have metal plates bonded on both ends or have plates only at one end.

The hollow rubber pad.

The ejector spring which are required in cutting and formimg press tools for sheet metal work are frequently designed with hollow rubber pad instead of metal spring. They are cheap and reliable in operation and make simple assemblies. The German AWF Committee of the press manufacturers has published a set of guidelines for the choice, calculation and arrangement of hollow rubber pad. Polychoroprene, nitrile and natural rubber have become the eatablished material. Nitrile rubber is stable under the influence of oil, polychoroprene are reasonably stable, and natural rubber is unstable but natural rubber does not tend to creep as much as nitrile rubber. Creep is understood to be the relaxation of the spring force under continuous stress.