GB890788A - Method of making machine belts - Google Patents

Abstract

890,788. Making machine belts. PIRELLI S.p.a. March 28, 1958, [May 11, 1957], No. 10077/58. Class 87(2). [Also in Group VIII] A machine belt is made by forming, e.g., on a mandrel, a cylindrical support layer by solidifying and hardening a liquid elastomer to a point at which it will not harden further, laying on the support a reinforcing layer or a number of such layers interspersed with intermediate elastomeric layers, and applying a covering layer of liquid elastomer which is subsequently solidified and hardened. The various elastomeric layers may be of the same or of different materials, for example of differing degrees of hardness. The elastomers used may be natural or synthetic, and may comprise a polyamine, polysulphide, polyvinyl chloride base resin, a polyester, or a polyurethane derived from an ester or ether, preferably a condensation product of naphthalene diisocyanate and glycol adipate. The cylindrical support layer may be east in an annular mould and transferred to the mandrel, or may be spread on the mandrel itself from a trough with the aid of a doctor blade. The reinforcement may comprise filaments or strips, of metal, textile material, or a metal-textile mixture, which may be wound on helically, Fig. 5, or may be a fabric. The outer surface of the support layer may be roughened, e.g., by grinding on the mandrel with a traversed grinding wheel, or by etching, for example with dimethyl formamide, before applying subsequent layers. The completed laminate, removed from the mandrel, may be used as such or divided into narrower belts by cutting in planes normal to the axis. Fig. 7 shows a belt having a support layer 1, moulded with teeth and of hard material, a reinforcing layer 9, and an outer layer 10 of softer material. If teeth are required on the outside, a belt, similarly made but of soft and hard materials respectively, may be turned inside out.