Patent GB-689148-A (GB)
Title: Improvements relating to methods and apparatus for the manufacture of pneumatic tyres
IPC: B29D30/06
Filed: 1951-05-15
Abstract: 689,148. Tyre-moulding machines. FRANK, P. A. May 15, 1951, No. 11356/51. Class 87 (ii). A machine in which a flat-built tyre is shaped into tyre form by a diaphragm and then vulcanized, has the diaphragm 29, Fig. 15, arranged to be moved out of the space between the mould halves 23, 24, when the press is open, to facilitate positioning of the flat tyre and the removal of the finished tyre. The mould halves 23, 24 may be fixed to plates 21, 27, Fig. 1. Insulating boards 22, 22<SP>1</SP> are interposed between the moulds and the plates. The lower plate 27 is fixed to the base 1, and the plate 21 is adjustably connected to a head 4 which is reciprocated on columns 2 by means of levers 7 connected to geared cranks 8. The diaphragm is closed by upper and lower heads 30, 31, the lower head being supported on a seat 38 on a member 37 fixed to a piston 40. The heads are urged apart by a spring 58. The member 37 has notches which receive locking plungers 45. Curing medium under pressure is supplied .to the diaphragm through a passage 48 and removed through a passage 49. In a modification, Fig. 4 (not shown), the spring 58 is replaced by a spring between the two heads, and the construction of the piston arrangement for moving the lower head is modified. In a further modification (Fig. 5, not shown), the upper head is moved upwardly with the upper mould for a predetermined distance and is then automatically disengaged; the locking plungers 45 engage in slots instead of notches in the member 37 to allow an additional upward movement of the member 37, which movement allows the lower beads of the tyre to be lifted off the lower mould; and the upper diaphragm head is axially aligned with the upper mould by an interengaging recess and projection. On operation, a tyre band T is placed between the moulds, the diaphragm is raised and inflated, and the mould closed, Fig. 11. The tyre is then cured and at the end of the curing period, the curing medium is exhausted from the diaphragm and the diaphragm flooded with a chilling medium. After removing the chilling medium, the diaphragm is again inflated to keep the beads of the tyre in engagement with the mould. The upper mould is raised and then, as shown in Figs. 14 and 15, the diaphragm is evacuated, the plungers 45 are withdrawn, and the diaphragm lowered. Alternatively the diaphragm may be lowered simultaneously with its evacuation. The tyre is then removed laterally from between the moulds. In a modification, Fig. 17, as the upper mould is raised after curing, a piston member 119 is raised to lift the tyre slightly and two or more jacks 126 are brought into operation by limit switches to move shoes 130 into engagement with the tyre. The shoes hold the tyre in this position until it is removed by the operator. Prior to removal the member 119 is lowered to remove the diaphragm from the tyre as in the previous modifications. A cable 131 may be attached to the diaphragm heads to prevent the diaphragm from being unduly stretched by the spring or springs holding the heads apart. The assembly comprising the diaphragm and its heads may be unscrewed from the top of the piston member for repair. Specifications 522,521 and 554,858, and U.S.A. Specifications 1,389,442, 1,942,797, 2,243,532, 2,296,800, and 2,337,857 are referred to.