GB644354A - Improvements connected with the injection moulding of small articles - Google Patents

Abstract

644,354. Injection-moulding of small articles. MAZZONI, L. Aug. 27, 1946, No. 25640. Convention date, June 24, 1943. [Class 87 (ii)] Beads, thin plates, buttons, &c. are made by injecting moulding material through channels 9, Fig. 3, formed in superposed mould parts 5, 6, 7 to cavities 1 formed in opposite faces of two parts 4, 5, the cavities 1 being so shaped as to form a depression in one or both sides of each moulded article and the channel outlets being of small diameter and located at points in the cavities corresponding to the bottoms of the depressions in the moulded articles. After solidification of the material in the cavities and injection channels, the upper part 7, Fig. 4, of the mould is raised, then the part 6, Fig. 5, is raised, carrying the sprues 10 with it to fracture the connection of the sprues to the moulded articles, and finally the parts 4, 5 are separated to release the articles. The parts 4-7, Fig. 8, are held between upper and lower pressureplates 12, 11, the upper part 7 carrying the injection orifice 14 leading to the channels 9. The mechanism for opening the mould comprises a tubular push-rod 16 rigidly connected to a plate 17 located in a chamber 18 in the lower plate 11, the plate 17 carrying four pushrods 19 fixed to the part 6. The rods 19 pass freely through sockets 20 in the part 5, the sockets being freely slidable in the part 4, and shoulders 21 on the rods 19 abut against recesses in the sockets 20 when the rods 19 are raised, this moving the part 5. The tubular push-rod 16 is traversed by a push-rod 22 secured to a plate 23 carrying rods 24 which pass through the parts 4, 5, 6 and form rejectors for the sprues in the part 6. A strong spring 25 tends to retain the push-rods 16, 22 in the extended position whilst springs 26 on the pushrods 19 tend to raise the part 6 with respect to the part 5. On opening the part 7, the spring 25 retains the plates 17, 23 at the bottom of the chamber 18 against the action of the springs 26 which tend to raise the part 6 with the pushrods 19. The push-rod 22 is then progressively raised carrying with it the plate 23 and rods 24 and permitting the plate 17 to rise under the action of the springs 26 taking with them the part 6 which raises with it the sprues which are torn from the moulded articles. The part 6 ceases to rise when the shoulders 21 abut against the sockets 20 and then the rods 24 continuing their upward movement effect the sprues. As the upward movement of the rod 22 continues, the tubular rod 16 is eventually carried with it and the plate 17 then resumes its upward movement raising the rods 19 which by means of the sockets 20 raise the part 5 and permit the moulded articles to be removed. The beads &c. may be moulded on a cord or braid or on a series of parallel cords to form a pseudo-fabric, the mould having grooves to accommodate the cord &c. Beads may be moulded in successive lots on braid, the braid being advanced to a new moulding position after the moulding of one lot of beads.