Patent GB-855082-A (GB)
Title: Method and apparatus for building an air spring bellows
IPC: B29D22/02
Filed: 1958-02-18
Abstract: 855,082. Pneumatic springs. GENERAL TIRE & RUBBER CO. Feb. 18, 1958 [Nov. 7, 1957], No. 5277/58. Class 108(3). An air spring is built by assembling rubber plies on a building drum 4, Fig. 2, placing a large bead ring at the left-hand end of the building drum 4, and a smaller bead ring at the right-hand end of the drum 4, folding the plies over the bead rings and stitching the plies down. A tube of uncured rubber which forms. the inner surface of the air spring bellows is placed on a tube 12, Fig. 2. The tube 12 has an inflatable bag which is inflated by compressed air to remove any wrinkles from the rubber tube. The tube 12, which is carried on a turret 11, is aligned with the building drum 4 by rotating the turret. The rubber tube is slid from the tube 12 on to the building drum 4. Plies of cord fabric and an outer sheet of rubber are wound about the tube on the building drum 4. The plies and the sheet are applied to the tube by an endless conveyor belt which presses them against the rotating cylinder 4. The end of the laminated tube is manually nipped inwards and bead rings h, g, Fig. 25, are positioned by a bead ring positioning tube 13 which is also carried on the turret 11. Compressed air is admitted to an air bag carried by the building drum 4 to expand the laminated tube against the interior of the bead ring h, whilst the bead ring is held against axial movement by thrust fingers 125, Fig. 25, and also to expand the portion of the tube between the ring h and the adjacent end of the tube to a diameter greater than that of the ring h. While the bead positioning tube 13 is held in the position shown in Fig. 25 a bag confining sleeve 64 is moved axially towards the bead ring h to cuff the end of the tube over the bead ring h. Before the turret is retracted to withdraw the bead placing unit 13, a second air bag 78, Fig. 28, carried by the building drum 4 is inflated to expand the reduced end of the laminated tube against the interior of the bead ring g, and, when the bead positioning tube carrier 104 Fig. 18 (not shown), is withdrawn to stretch the end of the tube to a diameter greater than that of the ring g. The turret 11 is now turned to bring a unit 14 into axial alignment with the drum 4 and is advanced to engage the unit 14 with the air bag 78. A member 133, Fig. 31, carried by the unit 14 cuffs the end of the tube over the bead ring g by forcing the air bag 78 round over the bead ring g. Air springs of different sizes and with different sized bead rings may be built by interchanging the necessary parts of the machine. The Figures include a schematic diagram of the various air valves and their associated relays which control the movements of the machine and the inflation of the air bags. The completed air spring is moulded and vulcanised in a conventional manner. To build an air spring in which the bead ring differs greatly in diameter it is desirable that the small bead ring be applied before the large bead ring is positioned around the tube. A small bead ring g<SP>1</SP> is positioned by a unit 13a, Fig. 40 and the air bag is expanded within a carrier 104a to fix the bead ring g<SP>1</SP> in position, after which the turret 11 is retracted and turned to bring an air bag confining cone 133a into axial alignment with the building drum so that the cuffing operation over the small bead g<SP>1</SP> may be completed. The air bag confining cone 133a, Fig. 42, carries a bead ring supporting sleeve 106a which positions the bead ring h<SP>1</SP>. The tube is now expanded and cuffed over the large bead ring h<SP>1</SP> as previously described.