Abstract:
A push-pull closure which includes a base for securing to a container and which base includes an upper plug which seats within an opening in a valve lifter which is moveable with respect thereto between a closed position and an open position and wherein a cap is provided for covering the valve lifter when in a closed position. A tamper indicating seal is applied over a portion of the top of the valve lifter and the plug of the base in order to provide a seal therebetween and to provide evidence of tampering or of first opening of the valve lifter from the closed position to the open position.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to push-pull type closures which make it possible to drink directly from a neck of a bottle. 
     2. Description of the Related Art 
     Such closures are conventionally composed of a base, a valve lifter and a protective cap, as is seen, for example, in U.S. Pat. No. 5,813,575. 
     The cap and/or the valve lifter may be provided with tell-tales or tamper indicating components for showing tampering. Such tamper indicating components complicate the manufacturing of molds, molding and assembly of the three parts. 
     SUMMARY OF THE INVENTION 
     The invention has for its object to provide a closure system of the type set forth hereinabove comprising a perfect sealing means before opening and forming a tamper indicator upon first opening. 
     To this end, the invention relates to a push-pull closure which includes a base provided with an internal thread, a valve lifter associated with the base and movable relatively to the base between a closing position and an opening position, and a cap covering the valve lifter before the closure is opened for a first time, and wherein the closure comprises a tamperproof inner seal welded or adhered on a top part of the valve lifter. 
     An outer lateral skirt of the base is extended along its lower part by a tamperproof band connected by frangible lugs to a lower edge of the skirt. 
     The frangible bridges or lugs are separated from one another by zones of abutment abutting against the lower edge of the outer lateral skirt when the closure is positioned on a neck of a recipient or container. 
     The valve lifter comprises a convex top extended, in its lower part, by an annular wall of which the shape of the inner surface corresponds substantially to an outer surface of an upper part of the base. The wall of the valve lifter comprises an inner shoulder abutting, when the valve lifter is in a closed position, against a surface of a shoulder of the base. The inner surface of the wall is, in its upper part, in contact with a bead defining an end zone of the base. Clips inside a cap are in register with the bottom wall of the valve lifter so as to secure the cap upon reclosure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Other objects and advantages of the invention will be more clearly understood in the course of the following description of an embodiment with reference to the accompanying Drawing FIGURE which is a longitudinal cross section of a closure system according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the following text, the terms “upper”, “lower”, “top”, “outer”, “inner” will be employed, unless mentioned to the contrary, with reference to a point P located at a center of the closure system. 
     The closure system shown comprises three parts, a base  1 , a valve lifter  2  and a cap  3 . The assembly is a revolution about a vertical axis  4 , in the embodiment shown. 
     The base  1  comprises an outer lateral skirt  5  provided with an internal thread  6 . At the top of the outer lateral skirt there extends a substantially horizontal annular wall  7  which is perpendicular to the outer, lateral skirt. The annular wall  7  is inwardly limited by a substantially vertical wall  8  which is concentric to the outer lateral skirt  5 . 
     The wall  8  extends upwardly over a height h 8  and extends downwardly, below the surface formed by the wall  7 , to form an inner annular skirt  9  concentric to the outer lateral skirt  5 . The inner skirt  9  comprises, in its lower end, an outer annular bead  10  forming a sealing lip. In the embodiment shown, the bead  10  extends over a height h 10  of the order of half of the vertical dimension h 9  of the inner skirt  9  or of height h 8 . 
     The outer and inner skirts define, over height h 9 , an annular space E limited upwardly by wall  7  and open downwardly. An upper surface  11  of the wall  8 , which is substantially horizontal, forms a surface of abutment for a lower edge of a skirt of cap  3 . 
     An upper part  12  of the base  1  comprises two cylindrical zones  13 ,  14  of decreasing diameter, from bottom to top, separated by a shoulder  15 . The shoulder  15  defines a truncated outer annular surface  16 , abutting against a complementary surface  31  of the valve lifter  2 , when the closure is in a closed position. The zone  14  includes, near its free edge  17 , an outer annular sealing bead  18 . 
     The outer lateral skirt  5  of the base  1  is extended in its lower part by a tamperproof band  19 . This tamperproof band  19  is connected by frangible bridges or lugs  20  to a lower edge  21  of the skirt  5 . An upper part of the frangible bridges  20  are of reduced cross section compared to their lower part. These frangible bridges  20  are, in the embodiment shown, substantially triangular. The bridges are limited inwardly by a substantially vertical surface  22  and, outwardly, by a surface  23  inclined with respect to the vertical. 
     The geometry of the bridges  20  facilitates their rupture or fracturing in a vicinity of their areas of attachment with the tamperproof band  19 , when the closure is initially opened. 
     Bearing surfaces  24  separate the frangible bridges  20  from one another. These bearing surfaces  24  form crenelations. A distance between the lower edge  21  of the skirt  5  and the bearing surfaces  24  is very small and much less than a height of the frangible bridges  20 . 
     Consequently, when the closure is positioned on the neck of a recipient or container (not shown), the bearing surfaces  24  abut against the lower edge  21  of the skirt  5 . In this manner, premature rupture of the frangible bridges  20  is prevented. 
     An annular lip  25  extends a lower portion of the tamperproof band  19 . The lip  25  is turned inwardly, in manner known per se, when the closure is positioned on the neck of the recipient. 
     The base  1  may be made of a plastic material such as polypropylene or polyethylene. 
     The cap  3  comprises a body formed by a transversal top wall  26  and a lateral annular skirt  27  which is slightly truncated, widening downwardly. A maximum internal diameter D 27  defined by the skirt  27  is slightly larger than an internal diameter D 9  defined by the inner skirt  9  of the base  1 . 
     In one embodiment, the cap  3  comprises outer grooves or recesses  28  to facilitate gripping. In another embodiment, at least a part of the outer surface of the cap  3  is granite like. 
     The valve lifter  2  comprises a convex top wall  29  extended, at its lower part, by an annular wall  30 . An inner surface of the wall  30  is of a shape substantially corresponding to the outer surface of zones  13  and  14  of the base  1 . In particular, a shoulder  31 , inside the wall  30 , comes into abutment, when the valve lifter  2  is in a closed position, against the surface  16  of the shoulder  15  of the base  1 . However, a lower edge  32  of the wall  30  does not abut the surface  11  of the wall  8  of the base  1  when the valve lifter  2  is in the closed position. Similarly, an inner surface  33  of the wall  30  is, at its upper part, in contact with the outer bead  18  of the zone  14  of the base  1 . 
     Consequently, the valve lifter  2  is mounted on the upper part of the base  1  so as to create a seal in closed or pushed in position and to permit flow in a pulled or open position. 
     In order to secure the cap  3  upon reclosure, clips  42  inside the cap  3 , or equivalent, engage with an annular edge of the top wall  29  of the valve lifter  2 . 
     A seal with the neck of the bottle (not shown) is ensured by the annular sealing lip  10 . 
     In order to increase a hold of the caps  3  during screwing of the caps on a production line, notches may be made at the base of the caps so that they are in register with other notches made on the surface of the bases which function as bearing surfaces for the skirts  27  of the caps. Such notches make it possible to prevent rotation of the caps with respect to the bases when the closures are being screwed to containers, on the production line. The notches do not hinder rotation of the caps in the sense of opening, for example anti-clockwise, but prevent rotation in the sense of screwing the caps to containers. 
     The caps  3  may be made of translucent or semi-transparent material so as to allow the color of the valve lifters to appear. The color may be associated, for example, with contents of a receptacle on which the closures are applied. 
     A plurality of ribs made on the bases and on the caps, prevents mutual rotation of these two pieces. 
     A peelable inner seal  36  is secured, by adhesion, heat-sealing or any other equivalent process, above a plug  34  and the upper face  38  of the convex bottom wall  29  of the valve lifter  2  to therefore form a seal  39  between an opening  35  in the valve lifter  2  which is normally sealed by the plug  34 . 
     This upper face and the upper face of the plug  34  are, before first opening, substantially in the same plane, which facilitates the positioning of the peelable inner seal. The plug is integrally formed with the base  1  and extends above the outer bead  18  thereof. A plurality of peelable materials, known per se, may be used for making the peelable secondary seal; such as aluminum polyethylene complexes, multilayers or laminates including ethylene-vinyl alcohol copolymer resin (EVOH) and the like. 
     The seal with the neck of the container is conserved when the closure is unscrewed until the bridges  20  joining the tamperproof band  19  to the outer lateral skirt  5  are broken. The seal of the closure is also accomplished by the plug  34  of the base  1 . Lateral surfaces of the plug seat and seal with the walls defining the opening  35  in the valve lifter  2 . 
     In the embodiment shown, the inner surfaces of the opening  35  includes a substantially vertical inner annular wall, a first substantially horizontal annular lower wall, a truncated upwardly tapering annular wall inclined by an angle included between 10 and 20 with respect to the vertical, a second substantially horizontal outer annular wall, and a substantially outer vertical annular wall. 
     The second substantially horizontal wall lies in a plane placed above the plane including the first substantially horizontal wall. 
     The plug includes from its upper edge towards its lower edge, a substantially vertical lateral surface, a first substantially horizontal lateral surface, a truncated annular surface inclined by an angle included between 10 and 20 with respect to the vertical, a second substantially horizontal lateral surface, a joining surface, and a substantially vertical surface. The truncated surface, second horizontal surface outer vertical surface form a lateral annular portion of the plug. 
     When the valve lifter  2  is closed, the outer annular recess of the opening  35  receives the lateral annular portion of the plug  34 . Thus, the truncated annular wall of the opening  35  comes into abutment against the truncated surface of the plug  34  and the first substantially horizontal annular wall of the opening comes into abutment against the first substantially horizontal surface of the plug. Further, the substantially vertical lateral surfaces of the plug are substantially in contact over their whole of their length with the substantially vertical annular walls of the opening  35 . 
     The bridges  20  joining the tamperproof band  19  to the lateral skirt  5  may be broken when the user desires for example to fill the container again. Consequently, the closure system is doubly tamperproof. First, the tamperproof nature is associated with the presence of a peelable, inner secondary seal  36 , and second, the tamperproof nature is associated with an initial unscrewing of the base  1  with respect to the neck of the container to rupture the lugs  20 .