Patent GB-161597-A (GB)
Title: Improvements in or relating to the manufacture of tyres
IPC: B29D30/06
Filed: 1919-07-31
Abstract: 161,597. Dunlop Rubber Co., Ltd., and Macbeth, C. July 31, 1919. Moulding india-rubber tyres. -In apparatus for moulding and vulcanizing pneumatic tyres and tubes &c., especially by the internal pressure system described in Specification 150,373, the mould parts are maintained closed by means of the medium, preferably steam, which is used for vulcanizing the tyres or for applying internal pressure thereto. In the form shown in Fig. 1, the lower mould A is integral with a cylinder A<1>, a heating space. A<2> being provided. The upper mould B has a diaphragm B<1> and a heating space B<2>, and is hinged on the lower mould by a pin C. The cylinder A' contains a piston D with a transverse rod D', to the ends of which are pivoted links D<2> the upper ends of which are pivoted to lugs on the upper mould B. Steam admitted to the cylinder through the valve A<4> enters the space within the moulds through the perforated diaphragm A<3>, and may be used to apply internal pressure to the tyres if that system is used, and also enters the heating spaces A<2>. B<2>, to vulcanize the tyres. The area of the piston D is greater than the area of the upper mould acted upon by the steam, so that the two moulds are firmly held together. To open and close the mould a hydraulic cylinder E may be used, a balance weight E<4> being provided. Alternatively, the piston D may be secured to the upper mould B by a central rod. In a modification two additional mould shells or rings are interposed between the upper and lower moulds, and hinged at different points round the circumference. Fig. 8 shows a press for tubes, in which the internal pressure system is not used, but in which the tube is pressed against a solid core or moulded with a tube in place which is filled with steam or air under pressure. The upper mould B is in the form of a ring, and the diaphragm A<3> of the lower mould forms the closed top of the cylinder, which may be put into communication with the interior of the mould through a pipe A<3>x. The heating spaces A<2>, B<2> also communicate with the cylinder through passages A<5>, B<5>x, the latter through the hollow hinge-pin C<x>. Figs. 9 and 10 show an apparatus adapted to take a pile of mkulds Ax which can be moved bodily into or out of the press. The annular support A forms the top of the cylinder A<1> containing the piston D. To the ends of the pin D<1>, which exteud through openings A<6> in the cylinder A<1>, are secured rods D<2> sliding in guides A<7> on the cylinder, and to the rods D<2> are secured supports G on which are rails G<1> adapted to be brought into alignment with fixed rails G<2>, G<3>, Fig. 10, to enable the wheeled carrier H bearing the pile of moulds to be run into the press, the piston D, rods D<2>, and supports G being raised for this purpose by steam admitted under the piston D<5> in the auxiliary cylinder D<6>. On steam being admitted above the piston D<5>, the pile of moulds is lowered until the carrier H rests on the plate A, after which the upper member B makes contact with the top mould. The flange of one of the wheels H<2> then depresses a trigger G<5> which unlocks the main steam valve and permits steam admission to the main cylinder A'. In the modification shown in Fig. 13, the support A for the moulds is connected by rods D<2> to the cylinder A, which is above the press and is formed with an auxiliary cylinder D<6>. The main piston has a hollow rod D<9> which carries at its lower end the clamping member B. The moulds Ax are piled on a wheeled carrier H, running on rails G<1> which may be lowered by a hand lever M<2> through cams M to allow the carrier to rest on the support A. Steam admitted to the cylinders D<6> depresses the piston D<5> and the main piston D until the member B bears on the top mould; steam is then admitted to the main cvlind.er A<1> and passes through openings D<10>, D" in the hollow rod D<9> to the space within the moulds. At the end of the operation the member B is raised by counterweights L<1>. The apparatus shown in Fig. 15 is used where great pressure is required, as for solid tyres. The upper part of the clamping member B is formed with inclined surfaces N. Within the cylinder A' is an auxiliary cylinder P, the piston P<1> of which is provided with rods P<2> carrying at their outer ends rollers P<4>, P<5>, bearing respectively against horizontal portions of the cylinder A<1>, and the inclined surfaces of the member B, whereby when steam is admitted to the cylinder P great pressure is exerted on the moulds. The moulds are wheeled into the press on a carriage H running on movable rails G<1> as in Fig. 13. Steam for curing and applying internal pressure to the tyres is introduced within the moulds through the pipe R<2> from the pipe R supplying the cylinder P. Other arrangements for obtaining a mechanical advantage may be used so as to apply a clamping pressure on the moulds greater than the pressure within them.