Improvements relating to the manufacture of pneumatic tyres

922,396. Building pneumatic tyres. DUNLOP RUBBER CO. Ltd. Aug. 27, 1959 [Sept. 27, 1958], No. 30930/58. Class 144 (1). A rubber side wall is shaped from a flat band 16 by being expanded on a drum 1 into contact with an annular surface 8 of dished form which is complementary to the contour of the sides of a pre-shaped carcase 17, the side wall being held in contact with the surface 8 by vacuum means during application to the carcase side. As shown, the drum 1 carries an annular inflatable tube 3 to expand two flat bands 6 respectively against frusto-conical surfaces 8 of two shaper rings 4 which locate coaxially one at each end of the drum 1. Each ring 4 has a series of passages extending therethrough from its surface 8 to a vacuum chamber 7 provided on its axially outer face, and the two rings 4 are bridged by a cylindrical shroud 14 to define an annular cavity 15 into which the tube 3 expands to effect shaping of the bands 16. With the bands 16 vacuum held against the surface 8, each ring 4 is located coaxially with the appropriate bead 18 of the shaped tyre carcase 17, Fig. 3, the sides of which are then stitched, by means of rollers 19, to the shaped side wall 16. To ensure that the outer peripheral edge of the shaped band 16 is coaxial with the carcase, an annular knife edge 9 defines the outer edge of the shaping surface 8 to sever excess rubber during the shaping operation.