Machine for blowing bottles and other hollow articles from organic plastic materials

摘要

805,834. Blow-moulding hollow plastic articles. SHIPTON & CO. Ltd., E. April 9, 1956 [April 12, 1955 ; Oct. 24, 1955], Nos. 10459/55 and 30347/55. Class 87(2). [Also in Group XL(b)] In a machine for blowing hollow articles by extruding a tube of plastic material into a tow-part mould 55, and then blowing the tube in the mould, the drive to the extrusion screw 3 is stopped, when a desired length of tube has been extruded, by a photo-electric cell 78 which disengages a clutch 28, In operation when the light from a source 74 is interrupted by the tube, the cell 78 energises a coil causing the clutch 28 to be disengaged, and operating a valve 83 which allows air to be supplied to a cylinder 44. The piston-rod 43 of the cylinder 44 rotates a valve 11 to allow the plastic material to be fed to a desired nozzle. At the same time, a boss 46 on the rod 43 operates valves as follows : (a) valve 19R to cut off the air supply to the right extrusion nozzle (b) valve 73L to prevent the left ejecting cylinder 72L from operating (c) valve 58L to close the left mould around the extruded tube (d) valve 58R to open the right mould (e) valve 19L to supply air to the left nozzle to blow the hollow article, and (f) valve 73R to eject the hollow article suspended on the right nozzle. After a predetermined time, the valve 83 is restored, the clutch 28 is re-engaged, and the extrusion begins from the other nozzle. The electrical timing circuit (see Fig. 7, not shown) may include a counter and relays to stop the supply to the motor if the light fails. The invention may also be applied to a single nozzle machine which may operate with several moulds successively moved into position on a rotary table as described in Specification 564,350. Different sizes of bottles may be made by adjusting the position of the light and the cell. The position of the cell may be adjusted automatically in a controlled sequence or by cams. The moulds 55, Fig. 3, are fixed on adjustable tables 22. Openings 80 are provided to prevent the moulds interrupting the light beam. The mould halves are mounted on pivoted links, and are provided with walls 69, to close the lower end of the tube, and cutting parts 70. The formed bottles are ejected by forked members 71. Flow regulators may be fitted to the various cylinders to control e.g. the speed of the piston rod 43, and the mould opening and closing speeds. Specifications 700,984 and 794,730 also are referred to.