GB733206A - Improvements in or relating to the manufacture of vehicle tyres - Google Patents

Abstract

733,206. Building tyres. CONTINENTAL GUMMI-WERKE AKT.-GES. Dec. 8, 1952, No. 31073/52. Class 144 (1). Vehicle wheel tyres are made by the flat band process on a rotary building drum 1 the surface of which has a circumferential groove 10 at each end for locating the bead rings 19 after application of the tyre plies or bands 20 on the drum, the drum being radially expansible, one stage only, to stretch the band 20 into holding engagement with the bead rings 19 prior to folding of the end portions of the band over the bead rings by means of axially movable segmented drums 12 located one on each side of the building drum 1. As shown the surface of the building drum 1 comprises a plurality of segments urged radially inwardly by rubber-block springs 2 against an inflatable annular bag 5 supplied with pressure air via tubes 6, 7 extending through a shaft 4 on which the drum 1 is mounted. The ends of the drum 1 slope radially inwaidly from the locating grooves 10 to provide a cam surface for the adjacent ends of the cylindricallyarranged segments forming the ply-folding drums 12. The said adjacent ends, which are provided with stirrups to support helical springs 18 serving as stitching rollers, are spring-urged radially inwardly to maintain stitching pressure on the band 20 during the ply-folding process. The axially outer ends of the folding-drum segments are pivoted to bell-crank levers 13 operable by axially movable setting-rings 14 to move the axially outer ends of the folding- dium segments radially outwardly. Axial displacement of the folding drums also is effected by the setting-rings 14, each of which is connected by a biacket 15 to a separate pistonoperated rod 16. In operation the left-hand folding drum 12 is moved to the left away from the building drum, Fig. 2, to allow placing of the bead rings 19 in holders, not shown. This folding drum 12 is then moved back, ready to receive carcase plies or bands applied to the drum 1 to form the flat band 20 and the bead rings are sited over the drum grooves 10, Fig. 5. The building drum 1 is then expanded by inflation of the air bag 5 to unite the band with the bead rings 19, Fig. 6, and with drum 1 still expanded, the left-hand setting ring 14 is operated first to expand the axially outer ends of the segments of the folding drum 12, Fig. 7, and then to move the segments over the drum 1 to effect turnover, Fig. 8. The left-hand drum 12 is then retracted and the process repeated for the right-hand drum 12. In the construction shown, the folded end portions of the band 20 overlap in the centre region of the band and if desired a tread band, or additional plies may be wrapped round the band 20 before collapsing of the drum for removal of the tyre band.