Patent GB-696488-A (GB)
Title: Improved apparatus for performing finishing operations on moulded articles
IPC: B29C43/00
Filed: 1950-07-21
Abstract: 696,488. Ornamenting. A.C.I. PLASTICS PROPRIETARY, Ltd. July 21, 1950. [July 25, 1949] No. 18257/50. Class 93. [Also in Groups V and XVI] Apparatus for performing finishing operations on moulded articles comprises a spaced-apart and opposed pair of article-holding members 21, 28, Fig. 1 ; a tubular member 13 open at both ends and adapted to support a moulded article M (e.g. a container or, as shown, an externally screw-threaded cap) ; hydraulic cylinders 24, 30 operable to depress member 21 and raise member 28 to clamp the articles between them and then to move the two members downwardly in unison to separate the article from the tubular member 13; and finishing means which engage the article during movement in unison of the holding members 21, 28, to remove flash from and/or to fill depressions in or colour or emboss the article. The machine shown comprises a disc 12 fixed on a shaft 10 which is oscillated through 180 degrees and back again by rack-and-pinion mechanism 11. To the disc at diametrically-opposite points are fixed two sleeves 13. When a sleeve is at position I it co-operates with dies 15, 16 to produce an article, e.g. a container or, as shown, a screw cap (see Specification 696,487). When the sleeve, with the moulded screw cap M, has been swung to position II, unscrewing heads 21, 28 descend and ascend respectively (being moved by hydraulic cylinders 24, 30) to grip the cap between them, the head 21 passing through the sleeve 13. The head 21 is rotated by worm gearing 25, 27 as it descends (or it may be rotated continuously) and the head 28 is journaled for rotation on its hydraulic piston 29. The rotation of the heads unscrews the cap from the sleeve. Cylinder 24 is somewhat larger than cylinder 30, so head 21 forces down head 28 and the cap, and as the cap descends, still rotating, a cutting tool 34 removes the flash from the cap. The tool 34 may be fixed, as shown, or moved inwardly automatically to engage the cap as the latter descends. A valve 31 is then operated to return heads 21, 28 to their raised and lowered positions respectively, the cap remaining on head 28 whence it is removed to a shoot. Then disc 12 swings to position the other sleeve 13, with its moulded cap, at position II, this cap having been moulded by descent and ascent of dies 15, 16 simultaneously with descent and ascent of heads 21, 28. The head 28 may be supported on a spring, against which it is forced down by head 21, Fig. 5 (not shown). In another modification (not illustrated) the head 21 may descend only through a distance equal to the pitch of the thread on the moulded cap. Fig. 3 shows a head 28 modified to accommodate a stick 36 of wax or other material which is slidably supported in a tubular holder 37 forming an extension of piston 29. As the head 28 is forced down and the flash is removed, the wax etc. is forced by plunger 40 into contact with the underside of the rotating cap, whereby the wax is pressed into grooves which have been moulded in the cap to form designs, words, monograms, etc. Cylinder 37 is restrained against rotation by arm 47 which slides on guide rod 48. The wax-ejecting plunger 40 slides in a cylinder 39 formed in the hydraulic piston 29 that raises and lowers head 28, and is raised by oil pressure through 45, 44, 43 and lowered by spring 40a. Fig. 4 shows a head 28 incorporating a die 49 for impressing the lower surface of the cap, e.g. impressing gold leaf on to the cap. The die is secured to a hub 50 rotatable on piston 29. Head 28 rotates with hub 50 but may slide longitudinally thereon, and is urged upwardly by spring 35. As head 21 descends, head 28 is pushed down against spring 35, uncovering die 49, which is thus pressed against the cap, the heads 21, 28 and die 49, all rotating. The die is heated electrically by means of conductors 52, 53, 58, 59, stationary contact rings 54 and contact strips 56 rotating with hub 50.