Patent GB-969553-A (GB)
Title: Tire building machine and method of building a tire
IPC: B29D30/36
Filed: 1962-02-16
Abstract: 969,553. Tyre building machines. UNITED STATES RUBBER CO. Feb. 16, 1962 [May 28, 1961], No. 6032/62. Heading B7C. In a tyre-building machine wherein the building drum 1 comprises a flexible, cylindrical, axially inextensible diaphragm 10, formed by one, or a double, ply of rubberized parallel wires extending axially, or at less than 10 degrees thereto, and sealed at its ends to two coaxial, axially movable end-plates 8, 9, the end-plates are movable from extended positions where the diaphragm provides a cylindrical carcase-building surface, to an intermediate position where the diaphragm is inflated to shape the carcase partially for application of the breaker plies and tread strip thereto, and finally to a retracted position where the carcase shaping is completed and the carcase, breaker and tread strip are consolidated pneumatically against the reaction of a split restraining ring 11 encircling the tread, the end-plates then being moved apart, simultaneously with deflation of the drum and pressurizing of the space between the diaphragm and the tye to permit removal of the shaped tyre. The movements of the plates to and from their three positions, together with. the pressurizing or exhausting of the spaces inside and outside the diaphragm, are effected automatically, utilizing limit switches LS1, LS2 and LS3, operated by a cam 13 coupled to the end-plate 9, which determine the retracted, intermediate and extended positions of the end-plates. The building drum 1 has its two end-plates 8, 9 carried respectively on inner and outer telescopic sleeves 25, 24 which are slidably keyed together and are keyed within a tubular shaft 2 journalled in bearings 3, 4 and driven by a reversible motor M2. A shaft 26 having oppositely screw-threaded ends 47, 48 extends through the inner sleeve 25 with its ends engaged in correspondingly screw-threaded nuts 49, 50 attached respectively to the sleeves 25, 24 whereby on rotation of the shaft, simultaneous approach or movement apart of the end-plates is effected. The shaft 26 is driven by a reversible motor M1 through a pneumatic clutch 12. An air supply passage 27 extends axially through the shaft 26 to terminate in a chamber 87 in a valve member 83, of an air distribution valve 80, carried by means of a slip clutch 84 on the end of shaft 26. The air distribution valve 80, Fig. 8, comprises a housing 82, carried by the end-plate 8, within which the valve member 83 is permitted a 90 degree rotation limited by a stud 98 on the housing engaging an arcuate groove 99 in the valve member 83. The valve member has four equi-spaced radical passages 88, 89, 100 and 101, two of which 88, 89 communicate at their inner ends with the chamber 87 and the other two of which terminate at their inner ends in openings 102, 103 which, according to the rotary position of the valve member align either with openings 104, 106 or 107, 105 in the housing 82 all of which are open to atmosphere. In the position shown in Fig. 8, the passages 88, 89 connect the air chamber 87 with two pipes 90, 91 which supply the air to the inside of the diaphragm 10, and the passages 100, 101 connect two flexible pipes 94, 95, leading to the space between the diaphragm and the carcase, with atmosphere via the openings 104, 106. When the valve member is rotated through 90 degrees, which occurs on initial reverse rotation of shaft 26 to extend the plates away from the L.S.I. position, the pipes 94, 95 are placed in communication with the pressure air chamber 87, and the pipes 90, 91 are connected to atmosphere to collapse the diaphragm. The restraining ring 11 comprises two halves 11a 11b each pivoted on a shaft 126 below the drum and boltable together around the drum to encircle the carcase tread after assembly of the latter when the drum is in its intermediate position. The inner surface of the ring is contoured to the shape of the tread. In place of the ring 11, a stitching roller assembly 160, Fig. 19, comprising coaxial, independently rotable sections 161-165 is mounted below the drum for movement by a pneumatic piston and cylinder 173, 174 into consolidating contact with the tyre tread when the carcase is in the partially shaped condition provided by the intermediate condition of the drum. To facilitate removal of a finished carcase, a bead retaining ring 120 associated with endplate 8 is detachably mounted on the plate 8 by a bayonet attachment. To enable use of the drum for manufacturing tyres of smaller crosssection and with the same or larger bead diameters, adaptor rings 184, 185, Fig. 21, or 186, 187, Fig. 22, respectively may be attached to the end-plates 8, 9. The Specification describes a control circuit for automatic electric and pneumatic operation of the machine.