GB740860A - Improvements relating to moulds for recapping or retreading motor tyres - Google Patents

Abstract

740,860. Retreading tyres. HAMILL PROPRIETARY, Ltd., B. A. Oct. 9, 1953 [Oct. 13, 1952], No. 27887/53. Class 87 (2). A tyre, retreading mould comprises complementary segmented sections 6, 7, 8, the section 8 being fixed to a base support 11 and the sections 6 and 7 being hinged at their lower ends upon horizontal axes 9, 10 so that air cylinders 30 having piston rods 33 attached to lugs 39, 40 on sections 6, 7 open them to the position shown in Fig. 4. The tyre is ejected by the upward movement of bar 63 operated from air cylinders 67 and guided by shaft 61 attached to rectangular plates 73, 74 moving on spaced roller pairs 77 on parallel upright members 71a, 71b and having further rollers 79 located within the space 71d so as to contact laterally the members 71a, 71b. The members 71a, 71b have an upstanding bracket 71f to which is attached a transverse bolt 32 to which projecting lugs 31 of cylinders 30 are pivoted. Each mould section has three annular mould cavities 80 each containing a matrix 81 with removable segmental members 82, fitting the cavity 20a defined by a steam chamber 20, which are retained in place by end flanged member 83. Steam is fed to the chamber 20 via feed pipes 21, 22 connected to swivel couplings 23 so that sections' 6, 7 may be fed via pipes 24, 25, the steam then passing to section 8 via pipes 26b, 26d and swivel coupling 26c. The air is controlled by valve 50, pipe 51 communicating with a source of pressure air which is fed to parts 43, 44 to open the mould segments 6, 7 and to ports 46, 47 to close the segments. In operation, the segments 6, 7 are opened by valve 50 which admits air to the cylinders 30 to open the segments 6, 7. The tyres T to be retreaded are then placed in the mould cavities over the tyre engaging bar 63 and the valve 50 operated to close the mould, bolts 55 retaining the sections in place. Steam is then admitted to vulcanize the retread, the mould opened and the valve 50 further operated to feed air to cylinder 67 which moves shaft 61 and thus bar 63 upwards to disengage the tyre. Hydraulic means may replace the air pressure means, and electrical heating replace the steam heating.