GB391921A - Improvements in or relating to process and apparatus for making brake linings and other fibre containing products - Google Patents

Abstract

391,921. Plastic compositions; vulcanization moulds; extrusion moulding-machines. WORLD BESTOS CORPORATION, 52, Courtland Street, Paterson, New Jersey, U.S.A.-(Assignees of Nanfeldt, W. ; 57, East 5th Street, Clifton, New Jersey, U.S.A.) Feb. 1, 1932, No. 2988. Convention date, Feb. 2, 1931. [Classes 70 and 87 (ii).] Laminated products useful as brake-lining material are manufactured from a moist mixture of fibrous material and a binder by separating the mixture into a number of relatively thin layers, and recombining the layers surface to surface while they are still moist. The mixture may comprise asbestos, rubber, sulphur, graphite, litharge, iron oxide, kaolin and magnesium oxide, and in preparing the mixture crude smoked rubber sheets mav be macerated with addition of magnesium oxide, litharge and sulphur and the mixture mixed with a rubber solvent to produce a cement ; the latter is mixed in turn with asbestos and a little rubber latex, and the other ingredients specified are then added and the whole mixture worked in a roll mill. The manufacture of the laminated products may be effected by forcing the mixture through a nozzle carrying a number of transverse partitions of substantial length in the direction of flow of the mixture, the nozzle also having an unobstructed portion beyond the partitions ; the mixture is divided by the partitions into layers, which are recombined surface to surface in the unobstructed portion. As shown in Fig. 2, the mixture is introduced into the pressure chamber 25 of a hydraulic press by forcing it from a transportable cylinder 10, one end of which is adapted to register with the chamber 25 and the other end of which has a moveable base 11 adapted to be engaged by the plunger 14 of a hydraulic press 15. When the chamber 25 is charged, the cylinder 10 is removed and a perforated screen plate 40, Fig. 3, fitted over the end of the chamber. A base cap 41, Fig. 3, is then slid into position over the screen plate. The cap 41 is attached to an L-shaped conduit 48, this conduit being frusto-conical in cross section at the end next to the plate 40, so that the mixture is compressed as it passes through the conduit. At the end remote from the plate 40 the conduit 48 is attached to a nozzle 51. As shown in Fig. 7, the nozzle 51 comprises two members 53, 54 bolted together to form a rectangular channel which tapers slightly between the points 60, 61. Above the point 60, partitions 62, 68, 69 are arranged in the nozzle, for the purpose described above. Fig. 12 shows an alternative method of arranging partitions 80 in the nozzle. The material extruded from the nozzle is delivered on to a travelling band which carries it through a drying oven to calendering rolls and thence to an edge grinder. The material is then pressed and vulcanized in a press 99, Fig. 16, comprising a number of pressure plates 101 and spaced grooves or channels adapted to receive predetermined lengths 100 of the material. The material may be treated in the press for 15 mins. at 325‹ F. and a pressure of 1500 lb. per sq. in. After pressing and vulcanizing, one face of the material is removed by grinding, and finally the material is bent by passage between a set of three rollers, to increase its flexibility. Reference is made to the use of cotton, wool, hemp and shredded leather instead of asbestos. Specification 367,176 is referred to.