Patent GB-964301-A (GB)
Title: Injection moulding apparatus for footwear
IPC: B29C45/20
Filed: 1962-04-24
Abstract: 964,301. Injection moulding soles. H. LUDWIG, [trading as DEUTSCHE SPEZIALMASCHINEN CO. H. LUDWIG K.G.]. April 24, 1962 [May 8, 1961; Oct. 5, 1961], No. 15478/62. Heading B5A. An apparatus for automatically injection moulding plastics material soles to uppers comprises a plurality of moulds 11 adapted to be automatically supplied to an injection unit 12 by means of a turntable, each mould having associated with it two. or more lasts 14 displaceable independently thereof, permitting successive location of each last in the injection position, and each mould being in two halves 13, movable at right angles to their junction line to close around the last 14. The last 14 is mounted to be vertically adjustable on a stand 16 and pivoted about a horizontal axis. Two examples are given: (i) The injection unit 12 comprises an injection head 20, displaceable vertically by a piston drive 21 and having a nozzle pin 22 displaceably mounted on it. The mould 13 comprises a bottom ram section 23 and two frame sections 24 having a closure device 25 for the injection passage 26. The injection head is upwardly displaced, guided by conical guides 31 into the recess of the frame sections 24. Plastics material from a pressure container is supplied via a passage 38 in a housing 33 on the head 20. As the closure cap 35 on the nozzle sleeve 34 of the housing 33 abuts against the frame sections 24, the nozzle pin 22 is displaced upwardly and pushes a stop member 29 of the closure device 25, thereby exposing the injection passage 26 and lifting the valve plate 22b of the nozzle pin from the injection nozzle 27, thus filling the mould cavity 49. At the opposite end of the mould cavity is a passage 51 through which excess material can pass working a cut-out device 50 for terminating the injection process. The injection head is displaced downwards causing the sudden closure of the passage 26 and the injection nozzle. The circular turntable is moved by one stroke and the injection process repeated, released either automatically or manually. The injection head is mounted so as to be readily exchangeable. (ii) (Fig. 9) The injection unit 12 comprises an injection head 20 and a device 61 preferably constructed as a piston drive, the head being displaceable relative to the drive by a second piston drive 62 which serves as a suction and pressure unit for supplying plastic material from a storage container 63 to the injection nozzle 64 which carries a nozzle pin 85. The injection head 20 and connecting socket 81 both have spring-loaded ball non-return valves 83, 84. On terminating an injection process, the piston 61a, with the valve 84 closed, is pushed back by compressed air from pipe 76 and thus the piston 62a is moved to the right by connecting rod 61c, and engages the cylinder 62b together with the injection head 20. Thus the nozzle pin 85 is withdrawn from two sealing bolts 90 mounted on the mould 13, closing the injection passage 89. When the cylinder 62b abuts the cylinder cover 72 of cylinder 62b the piston 62a moves relative to the cylinder, thus opening the non- return valve 83 and inducing plastic material into the cylinder 62b via connecting socket 81. When it (62a) abuts the cylinder cover 78 of cylinder 62b the non-return valve 83 is closed automatically through spring 83a. When a new injection station 11 is in position, pressure medium is fed via pipe 75, and the piston 61a moves to the left, thus moving the piston 62a via rod 61c. The piston 62a engages the cylinder 62b and the injection head 20 and they move together, both non-return valves being closed until the head 20 abuts the mould 13, the nozzle pin 85 then opening the injection passage 89. The piston 62a now moves to the left and relative to the cylinder 62b, the valve 84 opens and the plastic material is injected.