GB368765A - Improvements in frictional materials for brakes, clutches, variable friction gearingand the like - Google Patents

Abstract

368,765. Compound fabrics ; brakes; clutches ; friction gearing. ROBERTSON, J. H., ROBERTSON, J., and GUTTERIDGE, L., 1, Albemarle Street, Piccadilly, London. Dec. 10, 1930, No. 37258. [Class 140.] A frictional material for variable friction gearing, brakes, clutches, &c. consists of a non-combustible fibrous material, such as woven asbestos fabric, treated with a binder, e.g. a phenol-formaldehyde resin, and combined with cork or a composition of granulated cork or cork flour also treated or impregnated with a binder, the two materials being made up in alternate layers so that both components are exposed at the wearing surface. Preferably, compressed granulated cork is treated with the binder, spread under heat and pressure on a linen &c. backing, similarly treated with the binder, and combined in alternate layers with the treated asbestos fabric as shown in Fig. 2, in which a, a<1>, a<2> are the asbestos layers and b, b<1> the cork ; the cork layers are preferably thicker than the asbestos and the inner layers of the asbestos are thinner than the outer. When the material is to be built into the form of a ring, the sheets a, b are wound one over the other on a former, the ends of the sheets secured, the whole placed in a mould and heated under pressure to harden the binder. The composite block or ring may be cut into sheets, blocks, segments, or annuli so that the individual layers extend at right-angles to the wearing surface. In Fig. 5, the composite ring produced is shown in cross section ; a bevelled surface e<1> may be formed thereon to engage with a conical disc f to form a variable speed friction gearing. The Provisional Specification states also that the asbestos may be used in the pulverized or finely ground form, rolled out or pressed into a sheet after incorporation with the binder, and glue, gelatine, and casein products may be used as binding-material. Alternatively, other fibrous materials, such as ramie, cotton, silk, wool, or flax in yarn form, may be employed.