Composite rubber pads for mechanical and acoustic damping - esp. for use between railway line sleepers and particulate track bed

摘要

Pads for damping vibration by steel railroad tracks on solid sleepers supported on a gravel bed are laminates of a layer of closed cell expanded rubber on a layer of solid rubber which protects the former from damage by the gravel surface. The pads are placed under the line of the rails, between the sleepers and the gravel. Pref. the two layers are fabricated and pre-cured separately, then placed in a common hot press mould for simultaneous lamination and post curing. Specifically claims such pads where the material for the solid layer has a hardness of 80-95 Shore A, approximately 200% elongation to break, an elbow tear resistance of 30 daN/cm and an abrasion resistance (DYN 53.516) of about 250. The microcellular material has an apparent relative density of 0.4-1.0, a compressive modulus of 130-300 kg/mm, a compressive yield strain of 40-5% (for materials of 0.4 to 1.0 density respectively) and compression set of 70-10% accordingly. The layers may be 8-20 mm thick. May also be used beneath machine tools, motors, etc., to suppress both mechanical vibration and noise.