Patent GB-650163-A (GB)
Title: Apparatus for packaging articles
IPC: B65B9/04
Filed: 1948-01-17
Abstract: 650,163. Packaging by wrapping up. DUNLOP RUBBER CO., Ltd., HOGG, W. H., GRAY, T. E. H., and HYTCH, A. H. M. Jan. 17, 1948, No. 1509. [Class 94(i)] [Also in Group XI] Apparatus for packaging articles in a wrapping of thermoplastic material, comprises two relativelymovable members having cavities in opposed faces adapted to register with each other and form a chamber for an article to be wrapped when the faces are brought together, means for setting up a high frequency alternating electric field between the faces over an area surrounding the cavities, and means for holding sheets of thermoplastic material over the cavities in contact with the faces, comprising air passages in the members surrounding the cavities and adapted to be connected to a vacuum line. Each upper and lower member 1, 2, Figs. 5, 6 has a hemispherical wrapper-shaping recess 13 connected with a vacuum line by a passage 15, and surrounded by a sponge rubber ring 16 which is connected by an annular passage 11 to a vacuum pump (not shown). The lower passage 15 is formed in an ejector member 14. An annular ridge 28, Fig. 6, projects from a facing 27 of insulating material on the member 1 to form a cutter and there are additional slidable cutters 18, 18a. A ring 17 of electrically conductive material is embedded in the insulating material 27. Sheets of thermoplastic wrapping material, which may be plasticized polyvinyl chloride, a mixed polymer of vinyl acetate and vinyl chloride, or a polyvinyl-butyral, are pro-. vided by webs passing from rolls 28a (the upper roll only, shown in Fig. 5) over the opposed faces of the members 1, 2 and on to an intermittently rotating roller (not shown), common to upper and lower webs. The upper web passes through a slot 22 in a slidably-mounted feed guide 21. Rip tape is fed from a roll 30 (not shown) through a narrow slot 23 in the guide 21. Feed and delivery shoots and an articledischarging piston, Fig. 4, (not shown) are described. In operation, vacuum is applied to the pipes 10, 15, a ball passes from the delivery shoot to the lower recess 13 and the opposed faces of the members 1, 2 are moved into engagement. A high frequency electric field is applied between the ring 17 and the lower member, to seal the thermoplastic material around the ball, and the material around the seal is severed by the cutter 28. The rip tape which passes around the ball beneath the upper wrapping sheet, is severed by the action of the cutters 18, 18a. The tape is sealed to the webs by an extension 20, Fig. 5, of the ring 17, so that it is drawn off its roll on the subsequent rotation of the common feedroll when it draws the webs into position for the subsequent package. The package is ejected by the pin 14 and displaced by the discharging piston into the delivery shoot. The various operations described above may be effected by compressed air mechanisms and their sequence controlled by a timing mechanism. In another construction, the upper member, Fig. 1, is formed with a cylindrical cavity 3 vented to atmosphere at 6. Vacuum is applied to the sheets by a circumferential-series of holes 12 connected by an annular chamber 11. Printed matter may be applied to the wrapping material before or after the wrapping process, allowance in the former case being made for distortion of the material during wrapping. According to the Provisional Specification means to prewarm the sheet material may be provided. Specification 620,912 is referred to.