GB1343572A - Containers with safety closures - Google Patents

Abstract

1343572 Safety closures W LEEDS and L A MICALLEF [trading as LEEDS & MICALLEF] 1 May 1972 20137/72 Heading B8T A safety closure .includes a cap 22 having thread elements 36a-36d and a container neck having two threaded zones 38 and 52. When the cap is fully applied, the thread elements 36a- 36d are in the position shown in Fig. 3. In order to remove the cap, it is unscrewed until thread element 36a comes into contact with cam surface 46 which raises the element up into an interference zone 42 where the thread elements 36a- 36d form interference fits in the gaps between corresponding projections 54a-54d on the container neck, Fig. 5 (not shown). The cap must then be both pulled and twisted to clear the interference: further twisting causes the trailing end of the thread element 36d to cam up the surface 48 on the container neck, until the elements 36a-36c engage the under-side of the thread 40, the thread element 36d being the first to disengage as the cap is screwed off. In a modification, Figs. 9-12 (not shown), the thread element (36a<1>) is obstructed.by a vertical surface (46<1>) so that the cap must be pulled axially to force the element (36a<1>) into the interference zone (42<1>) after which further screwing causes the element (36d<1>) to abut a vertical surface (48<1>). The cap must then be screwed in a reverse direction in order to clear the trailing end of the element (36d<1>) from a projection 56 on the thread of the container neck. The thread elements are then in position, Fig. 12 (not shown), for the cap to be screwed off with the element (36d<1>) leading. The container and closure may be made from plastics or glass, and a seal is provided either by a liner (34), Fig. 2a, (not shown), or by an annular lip depending from the inside of the end wall 30 of the cap.