Abstract:
A packaging unit has a container closed by a safety plug which has a maximum diameter equal to the outer diameter of the container opening and a smooth exterior to avoid any gripping surface. A cylindrical lip adjacent to the peripheral edge of the plug cooperates with the inner surface of the container opening to seal the opening. A slide is movable along a radial direction of the plug to extend beyond the edge of the container opening to provide a gripping surface for removing the plug. Safety detents may be provided which must be manipulated to permit movement of the slide.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a packaging unit which prevents or restricts access to the contents. Such packaging units are widely used for medicinal preparations, paints, varnishes, cleansing agents, rust removal agents and the like. These units generally include a container having a closure or plug which is designed to be difficult to open or remove. The closure or plug is often termed &#34;safety closures&#34; or &#34;safety plugs&#34;, and inasmuch as primarily children make up the group of people to whom unwarranted opening is to be denied, they are often called &#34;childproof closures&#34;. 
     A known design for a safety closure consists essentially of an internal cylinder provided with a sealing lip or bead and a flange-like continuation of the cylinder which mounts on the edge of the container opening. If desired, a retaining means for the contents may be provided which projects into the interior of the container. 
     An object of the invention is to provide a packaging unit with a safety closure which is simple and cheap to produce and which can be filled and sealed on standard automated packing lines such as are in existence in industry, and in the pharmaceutical industry in particular, without the need for significant modification. 
     This object is attained by the present invention in which a flange-like part of the safety closure projecting above the edge of the container opening has a maximum external diameter equal to the external diameter of the opening and tapers from the edge of the opening to the center so that no grippable peripheral area is provided and in which a slide is mounted in a flange-like part of the closure to move radially to provide a surface which may be used to remove the closure from the opening. 
     The invention is described in greater detail by means of example embodiments and reference to the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal section through a packaging unit according to the invention, in the area of the container opening. 
     FIG. 2 is a top view of the unit shown in FIG. 1. 
     FIG. 3 is a side view, partly cut away, of the slide shown in FIGS. 1 and 2. 
     FIG. 4 is a longitudinal section through a modified embodiment of the packaging unit. 
     FIG. 5 is a top view of the unit shown in FIG. 4. 
     FIG. 6 is a side view, partly cut away, of the slide shown in FIGS. 4 and 5. 
     FIG. 7 is a top view of a third embodiment of a safety closure according to the invention (without slide). 
     FIG. 8 is a top view of the slide for the embodiment of FIG. 7. 
     FIG. 9 is a longitudinal section through the unit shown in FIG. 7. 
     FIG. 10 is a longitudinal section through the slide shown in FIG. 9. 
     FIG. 11 is a section along line XI--XI in FIG. 9, with the slide inserted. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Only the upper part of the container 2 of the packaging unit directly adjoining the mouth or opening 1 is shown in the embodiments exemplifying the invention. The exterior surface of the container 2 adjacent to the opening 1 is free of any radial projections or protruberences. 
     The safety closure, or plug, generally designated as 3, includes an internal cylinder 5 provided with sealing means in the form of a torus 4, and a flange-like part 7 projecting above the edge 6 of the opening 1. The maximum external diameter of the flange-like part 7, as shown in FIGS. 1 through 6, is equal to the external diameter of the container 2 at the opening 1, and the thickness decreases in the direction away from the centerline M so that a sloped surface 8 is formed, (tapered in cross section), with the result that no peripheral surface is created which can be gripped for removal of the plug, for which reason the container cannot be readily opened. 
     Another internal cylinder 9 in the safety closure 3 can accommodate a contents retaining means in the form of a bellows 10. 
     Opening of the container is made possible by a slide 11 which can be displaced radially so that a portion extends over the outer edge of the opening 1 (FIGS. 1 through 3), 12 (FIGS. 4 through 6) or 22 (FIGS. 7 And 11) to permit removal of the safety closure 3. 
     The slide 11 is movably mmounted in a slot 13 provided within the safety closure 3, and the outer end portion 14 of the slide is accessible from above, making it possible to move the slide in the direction of arrows A, from the closed position (solid lines, FIG. 2) to the open position (broken lines, FIG. 2) or to return it to the closed position. To facilitate this movement, the outer end portion 14 of the slide 11 is provided with an indentation or recessed portion 15 into which the user can insert a fingernail. 
     Complete withdrawal of the slide 11 is prevented by lateral projections 16 acting in conjunction with a lateral extension 17 of the slot 13. A slot 18, in the form of a circular sector, in the sloped surface 8 is provided for the insertion of the slide 11 into the slot 13 during manufacture of the safety closure 3. The slide 11, like the closure 3, is preferably made of a plastic material, and being flexible can be bent slightly until its projections 16 are locked in the extension 17. 
     The embodiment illustrated in FIGS. 4-6 differs from that shown in FIGS. 1-3 primarily in that the slide 12 is not mounted in a closed slot, but is mounted in an open groove 19 having a cross-sectional shape of a swallowtail. The cross section of the slide 12 is accordingly not rectangular, as in the case of the slide 11 (see FIG. 1), but rather, as shown in FIG. 4, is adapted to the shape of this groove. The lateral projections 16 on the slide 12 and the lateral extension 17 of the groove 19, by means of which accidental complete withdrawal of the slide from the groove is prevented, are present in this embodiment as well. 
     As indicated by broken lines in FIGS. 2, the portion of the slide 11 projecting beyond the flange-like part 7 forms a handle which makes it possible to lift the closure 3 upward and at the same time to overcome an undercut 20 on the inner surface 21 of the container 2, adjacent to the opening 1. This is true also for the embodiment shown in FIGS. 4-6. 
     An especially childproof and thus preferable embodiment of the invention is illustrated in FIGS. 7 through 10. The slide 22 in this case has a T-shaped cross section, for example, and is mounted in a groove 23 of corresponding shape. The depth of the groove 23 is greater in the rear or inner area 24 of the groove than in the forward or peripheral edge area. Groove 23 is provided with lateral undercuts 25 which correspond to the T-arm of the groove, to receive the corresponding projections 26 of the slide 22. The depth of the undercuts 25, which is greater in the area 24 of the groove than in the forward area, is reduced to approximately the depth present in the forward part of the undercuts by strips 27 projecting downward into the undercuts. 
     Working in conjunction with the strips 27 are slots 28 in the lateral projections 26 of the slide 22, into which slots the strips 27 project when the slide 22 is fully inserted to block withdrawal of the slide into the open position indicated by the broken lines in FIG. 2. Such withdrawal is possible only when the rear part 30 of the slide 22, marked by an indentation 29, is pressed downward into the deeper rear area 24, to free the slots 28 from engagement with the strips 27 by elastically deforming the slide. The elastic deformation of the slide 22 is facilitated by a transverse groove 31 in the bottom surface 32 of the slide. After the part 30 of the slide 22 has been depressed, it is then possible to pull the slide into its outer position. 
     Complete withdrawl of the slide 22 from the groove 23, in this embodiment is prevented by a lip 33 projecting from the bottom surface 32 of the slide. When the slide 22 is withdrawn, the lip 33 strikes against a step 34 in an indentation 35 in the groove 23 to prevent further movement of the slide. 
     An additional safety feature impeding undesired opening of the packaging unit is illustrated in FIGS. 9 and 11. It is to be understood that this feature can also be provided in the embodiments discussed above. As shown in the drawings, the flange-like part 7 of the safety closure 3 projecting above the edge of the filling hole 1 has an external diameter which is slightly smaller than that of the container opening and engages an annular recess 36 in the lip of the container. This feature prevents insertion of a flat object, such as the blade of a knife or a screwdriver, into the gap between the upper edge 6 of the container and the bottom annular surface of part 7 mounted on this upper edge in the embodiments illustrated in FIGS. 1 through 6 and prying the safety closure 3 out of the container 2. 
     It is understood that stop means similar to the lateral projections 16 and extensions 17 shown in the embodiment of FIG. 5, could be substituted for the cooperating lip 33, step 34 and indentation 35 illustrated in FIGS. 7-11, and vice versa. 
     Of course variations of the specific construction and arrangement of the safety packaging unit disclosed above can be made by those skilled in the art without departing from the invention as defined in the appended claims.