Patent GB-933855-A (GB)
Title: Improvements in or relating to the manufacture of shoes
IPC: B29C35/00
Filed: 1958-09-05
Abstract: 933,855. Moulding rubber soles on to footwear uppers. BRITISH UNITED SHOE MACHINERY CO. Ltd., R. D. E. ELDRED, and S. E. FRAMPTON. Sept. 7, 1959 [Sept. 5, 1958], No. 28508/58. Class 87(2). A machine for moulding soles of sponge rubber or hard rubber, or a rubber of intermediate hardness such as microcellular rubber or semi-sponge rubber, on to shoe bottoms comprises a last for supporting a shoe upper, a pair of side moulds movable towards and away from each other widthwise of the last, a sole mould, power-operated means for effecting movement of the side moulds towards and away from each other, power-operated means for effecting relative movement heightwise of the last between the side moulds and the last and between the side moulds and the sole mould, and control means for the power-operated means which may be readily adjusted, at the will of the operator, to bring about after closing of the side moulds, the relative movement between the side moulds and the sole mould either before or after the relative movement between the side moulds and the last has taken place. The machine described by way of example is in some respects similar to that disclosed in Specification 892,465 in that it is operated by fluid under pressure, viz. compressed air, and has two stations at each of which is provided a pair of electrically heated side moulds and a last carrier supported on a crosshead 4 mounted for swinging movement between loading and unloading positions on a pair of parallel rods 6 forming part of the mechanism for raising and lowering the lasts. The opening and closing movements of the side moulds are, however, controlled by a different mechanism as will be hereinafter described. At each station an electrically heated sole mould is carried by a carrier 8. Instead of the piston and cylinder arrangement with which the machine of the prior Specification was provided for moving the side mould and the sole moulds, this machine has one piston and cylinder arrangement 10, Fig. 3, for moving the side mould carriers and a separate arrangement 12, Fig. 1, for raising and lowering each sole mould carrier. The arrangement 10 comprises a piston rod 14 movable in a horizontal direction fore and aft in the machine and is connected to a bar 16 pivotally connected to two pairs of links 18 providing a pair of horizontally disposed toggles, the outer ends of which are connected by links 20 with the inner side mould carriers 2. Links 26 assist in guiding the carriers in their movements towards and away from each other. Each arrangement 12 comprises a cylinder 30 and a piston 32, the former being fixedly secured to the machine frame and the latter directly connected with its associated sole mould carrier 8. Valve mechanism is provided for moving the lasts, the side moulds and the sole moulds in the desired sequence as will now be described. The piston and cylinder arrangement 34, Fig. 2 (not shown) associated with the raising and lowering of the lasts is double acting and the air supply to the upper and lower ends of the cylinder is controlled by two valve devices 1, 3, The cylinder of the side mould closing mechanism is single acting, a spring being provided for breaking the toggles and returning the side moulds to open position. Air supplied to this cylinder is controlled by a valve device 5. The cylinders of the sole mould lifting mechanisms are single acting also, the air supply being controlled by a valve device 7. When sponge rubber soles are to be moulded, a trip lever 71 is operated first to swing an actuating member 75 anticlockwise, Fig. 11, which causes the valve 5 to supply air under pressure to the side mould closing cylinder to close the side moulds and also causes, by means of a rocking lever 85, the valve 7 to supply air at reduced pressure through a reducing valve RV and inlet port 17 to the sole mould lifting cylinders. The side moulds close first and the sole moulds rise to trap rubber " skins " (which form the tread surfaces of the soles) previously placed upon the sole moulds against the undersides of the side moulds. The mould cavities are then loaded with the appropriate rubber material and a trip lever 73 operated to cause the lasts to descend. This downward movement of the lasts initiates action of a timer T by depressing a rod 103 which, in turn rocks a bell crank lever 105 connected to the timer T by a cable 107. The timer T is like that of the machine disclosed in said Specification and the cable 107 corresponds to the cable 464 referred to therein. After the time necessary for vulcanising the sponge rubber, the timer T actuates a microswitch M1 which operates a solenoid S1 causing latches 93, 95 to release operating levers 63, 65. Release of lever 63 causes a spring to move it over to a position in which valve 3 is connected to exhaust, the lasts remaining in their lowered position under gravity with a latch 91 retaining a lever 61 in a position in which the upper end of the cylinder controlling movement of the lasts is also connected to exhaust. Release of lever 65 causes springs to move it and lever 67 to positions in which ports 25, 27 are open to exhaust while the air supply to ports 15, 17 is cut off, the cylinders of the side mould closing and sole mould lifting mechanisms thus being connected to exhaust so that the moulds are opened. When the side moulds are opened, latch 91 is automatically caused to release the lever 61 which is returned by a spring to a position in which valve 1 supplies air under pressure to the upper end of the piston and cylinder arrangement 34 (not shown) which raises the lasts to their inoperative positions. Also described is the use of the machine to mould solid rubber soles, the sole moulds rising between the closed side moulds, after the lasts have been lowered, to apply the required pressure to the soles, and to mould microcellular rubber soles, the sole moulds rising to apply pressure during an initial stage of the vulcanising process and then descending to a predetermined level to allow the rubber to expand at a controlled rate and to a predetermined extent. A further procedure, which may be of advantage in the moulding of soles of " semi-sponge " nature in which relatively little blowing agent is used is to " cook " the rubber for a predetermined time without the application of pressure and then to cause the sole moulds to exert a pressure for a further predetermined period.