GB1168860A - Improvements in or relating to Tamper-Proof Screw Closures for Containers - Google Patents

Abstract

1,168,860. Making tamper-proof closures. JOHNSEN & JORGENSEN Ltd. 27 Dec., 1967 [30 Dec., 1966], No. 58654/67. Heading B3A. [Also in Division B8] A screw cap 20 is rendered tamper-proof by a frangible ring 50 whose upper and lower inwardly projecting flanges 52, 54 engage respectively an annular bead 28 rolled at the extremity of the skirt 24 of the cap 20 and an annular projection 16 on the neck of the container. As unscrewing of the cap is initiated the circumferential stress set up in the ring leads to fracture at one of a number of weakening longitudinal score lines (56), Fig. 3 (not shown), continued unscrewing dividing the ring into sections which pivot at neighbouring score lines and are easily removed to leave a simple screw cap. Rings 50 are formed from a continuous strip of material. Scoring is carried out by a device Ss comprising rolls 80, 82, the latter having peripheral scoring elements 83, and the strip is fed into a cutting and sealing station Sc by rollers 94 through a slotted guide opening 92 in a work head 85. The strip is bent to circular shape between the walls of a circular opening 90 in the work head 85 and a mandrel 89, and a reciprocating cutter 96 cuts off a predetermined length of strip. Before the cutter 96 reaches its fully extended position a seating rod 100 which is normally held in a retracted position is actuated inwards to press the leading end of the strip segment against the mandrel 89 so that the ends of the strip segment overlap when the cutter 96 descends and may be sealed together by the pressure of a heating element 102, a coating of bonding material having been initially applied at least to one surface of the strip. The turret mounting 87 supporting the ring on the mandrel 89 is then rotated 90 degrees to convey the ring to a rolling station Sr where the upper annular flange of the ring is formed by a rolling mechanism 110, the mandrel 89 being partly retracted so that its upper edge forms a die, controlling the profile of the rolled flange of the ring, Figs. 10-12 (not shown). The turret is then turned through a further 90 degrees to a discharge station Sd where the finished ring is ejected by an airjet 120. The ring is then placed over a cap in the fully screwed down position on a container with the upper flange 52 seating on the bead 28 of the cap, and the lower edge 54 of the ring is rolled under the projection 16 on the container.