The Hill Company is proud to offer high-quality Mason Industries INC products. Mason Industries INC is a respected manufacturer of noise and vibration control systems.
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 a 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.
Vibration isolation manufacturer shall furnish integral structural steel bases. Rectangular bases are preferred for all equipment. Centrifugal refrigeration machines and pump bases may be T or L shaped. Pump bases for split case pumps shall be large enough to support suction and discharge elbows. All perimeter members shall be steel beams with a minimum depth equal to 1/10 of the longest dimension of the base. Base depth need not exceed 14”(350mm) provided that the deflection and misalignment is kept within acceptable limits as determined by the manufacturer. Height saving brackets shall be employed in all mounting locations to provide a base clearance of 1” (25mm). Bases shall be type WF as manufactured by Mason Industries, Inc. (courtesy Mason Industries)
Seismic Cable Restraints shall consist of galvanized steel aircraft cables sized to resist seismic loads with a minimum safety factor of two and arranged to provide all directional restraint. Cables must be pre-stretched to achieve a certified minimum modulus of elasticity. Cable end connections shall be steel assemblies that swivel to final installation angle and utilize two clamping bolts to provide proper cable engagement. Cables must not be allowed to bend across sharp edges. Cable assemblies shall have an OPA preapproval from OSHPD in the State of California verifying the maximum certified load ratings. Cable assemblies shall be type SCB at the ceiling and at the clevis bolt, SCBH between the hanger rod nut and the clevis or equipment, or SCBV if clamped to a beam, all as manufactured by Mason Industries, Inc. (courtesy Mason Industries)