| abstract |
1413130 Moulding vehicle friction elements ABEX CORP 29 Dec 1972 [17 Jan 1972] 60147/72 Heading B5A [Also in Division C3] A method of producing a vehicle frictional element such as a brake lining or clutch pad from a mixture of phenol formaldehyde resin, fillers and asbestos fibres (at least 5%) comprises placing the dry mixture 10 in a mould cavity defined by a die 15 and a plunger 20, and compressing without heat to densify the mixture into a coherent body, which is thereafter removed from the mould and baked at 150-230‹ C. to cure the resin; to facilitate egress of air from the mould cavity during compression, the plunger is provided with grooves 32 in the side and end walls and face, (Figs. 1A and 1B) and perforated screens 34, 35 having perforations which are smaller than the grooves 32 are interposed between the plunger and the material. A sheet of kraft paper 36 between the screens and the material prevents blocking of the perforations by the material. A steel backing member 12 is placed in the die before the material 10, and is coated with an adhesive to aid bonding of the back to the material 10. The fillers used are cast iron, graphite, alumina, coke and barytes. Brass chips may be used instead of iron. In an alternative arrangement, the die 15 may have passages instead of the plunger 20.n[GB1413130A] |