GB767146A - Injection-moulding machine - Google Patents

Abstract

767,146. Injection-moulding machines. KEMP, K. W. LEE-. July 8, 1954, No. 20045/54. Class 87(2). The injection cylinder 1 is slidably mounted in a neck 29 of a hopper 26, being held in the raised position shown by a compression spring 23 disposed between flanges 20 and 24 on the neck and cylinder respectively. A ring 22 seated in a groove in the nozzle determines the upper limit of travel of the cylinder. The lower end of the cylinder carries a valve which is held closed by the pressure in the cylinder and by a spring 18 and is opened by being pressed against the mould. The valve comprises a stem 9 having an axial bore 12 communicating with an annular recess 14 in the stem. When the valve nozzle 10 is pressed against the mould the spring 18 yields, the stem rises and the recess 14 registers with ports 7 formed in a stationary sleeve 5, whereupon plastic material issues from the nozzle. Sleeve 5 is secured to a stem guide 3, and has fins 6 which touch the inside of the nozzle. The upper end of the cylinder is slidably mounted in the lower end of a sleeve 28 seated in a removable top 26<SP>1</SP> of the hopper 26. Within the sleeve 28 slides a member 31 carrying an injection plunger 30, this member being vertically reciprocable by a handle 34, shaft 32 and rack-and-pinion mechanism (not shown). To guard against excessive application of force to plunger 30 a friction disc or torsion spring may be disposed between handle 32 and shaft 34. Heaters 46, 47 surround the hopper neck 29 and the cylinder. The mould is secured between a fixed jaw 37 and a movable jaw 38 which is adjustable upwardly along inclined surfaces 40, against the pull of a spring 44, by means of a cam 42 turned by handle 45 and shaft 43. In a modification the jaw 37 may be movable. The surfaces 40 are formed on keys disposed in a slot 39 in jaw 38. The machine may be disposed horizontally.