Bolt Isolation Washer-Bushing
Up until the 1950’s most rubber mountings were designed to take the load in shear. Mountings were circular or sold in long strips, so the capacity could be controlled by size and durometer, or durometer and the cut off length.
Shear loading curves are straight line similar to steel springs. The deflection can be used directly in the frequency equation after dynamic stiffness correction. Unfortunately, shear mountings could and did fail because of bond failure between the rubber and metal. When overloaded, the mountings would bottom out. Compression mountings are less expensive for a given capacity and when overloaded, there is still a cushion. When loaded conservatively, the load deflection curve is similar to the straight line shear.
|Size||Rod Dia. Load (in)||Hole Dia. Required (in)
|125||1 1/4||1 1/2|
|150||1 1/2||1 3/4|