GB1374710A - Friction material and method of manufacture - Google Patents

Abstract

1374710 Yarns JOHNS-MANVILLE CORP 20 June 1972 [24 June 1971 (2)] 28803/72 Heading D1W [Also in Divisions B5 and F2] In the manufacture of friction facings e.g. for a clutch plate or brake mounting, two or more rovings composed of parallel glass filaments impregnated with a heat-curable cement are grouped together in parallel relation and continuous filaments of metal e.g. non-ferrous such as brass or zinc, are helically wound therearound to retain the rovings in a continuous bundle. The latter is spirally or randomly wound into a desired shape and dimension and then compressed, the cement is cured and the resultant body is ground to a required thickness. Prior to the rovings being wrapped, the cement e.g. 30-40% rubber, 20-30% accelerator and curing agent such as di-orthotolylguaridine, 15-30‹ resin and 20-30% filler, may be at least partially dried to remove volatile materials. As shown in Fig. 1, glass rovings 12 withdrawn from package 10 are maintained apart by a combing device 14 as they pass around a roller 16 in a cement bath 18. Impregnated rovings pass through eyelet 22 which wipes off excess cement, they are separated again in passing through rosette disc 24 (which may also remove any remanent cement) whence they pass through a drying tower 26 through which a counter stream of steam is passed between ports 28 and 30 to drive off volatile hydrocarbon parts of the cement. The partially dried rovings pass over pulleys 32, 34, and through a tower 36 wherein hot air is admitted and exhausted to and from ports 38 and 40, 42, thence through a winding apparatus 60 wherein filaments, supplied from symmetrically disposed spools carried by a continuously revolving platform 62, are wound in spaced helices around the rovings. The wound bundle passing axially through the platform is wound for storage onto a spool 50 by driven friction rollers 54, 56, such action providing the tractive force for passage of the continuous rovings through the apparatus. Subsequently the wound bundle 49, Fig. 7, is spirally or randomly wound from a spool 88 onto a revolving mandrel mould 90 comprising a pair of plates 92 mounted on a rotatable shaft 94 and spaced according to the desired thickness of the disc preform, the latter is removed from the mandrel, compressed between flat platens, initially cured by heat applied thereat and the curing is completed by a subsequent backing under reduced pressure in two stages of temperature conditions. The disc so formed is then ground and drilled to final size and to provide securing means.