Abstract:
Self-opening plastic closures having a pouring spout including a flange, a cutting member that is moveable in the spout and a screw cap for actuating the cutting member. In this invention, the cutting member carries out a translatory cutting motion by the rotational movement of the screw cap. In order to open the sealed packaging, to which the plastic closure is attached, different torques are brought to bear. According to this invention, first means and second means engage with one another successively to produce different advance paths for each revolution of the screw cap.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to a self-opening plastic closure including a pour-out spout with a flange for connection to a single-layer or multi-layer packaging foil of a closed packaging, with a cylindrical cutting element movably guided within the pour-out spout, and with a screw cap with a lateral wall having an inner thread and with a cover surface, wherein the screw cap is screw-connected to the pour-out spout with an outer thread, and the screw cap and the cutting element include elements which convert the screw movement of the screw cap into a purely translatory relative movement of the cutting element to the pour-out spout. 
         [0003]    2. Discussion of Related Art 
         [0004]    Self-opening plastic closures are to be understood as closures which are welded or bonded onto a completely closed receptacle of a single-layer or multi-layer packaging foil, and include a cutting element which when screwing open the screw cap for the first time, cuts open the packaging foil and holds it in the opened condition. The re-closure ability of the closure from then on is only effected by the screw cap. 
         [0005]    Plastic closures of this type have been widespread on the market for practically 20 years. Two different types have already been disclosed in one of the earliest application of a closure of this type. In particular, such self-opening plastic closures are either provided with a rotating cutting element or with a cutting element which executes a purely translatory movement, such as known from European Patent Reference EP 0328652. The cutting element is guided axially in the pour-out spout, and on an upper edge includes a ramp-like advance device, which with a corresponding ramp-like end-face of an annular wall segment presses this cutting element downwards when screwing off the cap. Accordingly, the cutting element includes a multitude of perforating teeth which are distributed over the entire periphery, with the exception of a short section without teeth, in order to avoid the packaging foil being completely separated from the packaging and falling into the receptacle. One problem with such a solution is thus the force to be mustered. The complete force to be applied must practically be mustered with only a quarter revolution of the screw cap. These closures could not assert themselves on the market due to the high forces which are necessary in order to open such a closure. 
         [0006]    An earlier version of a self-opening plastic closure with a rotating cutting element is known from PCT Publication WO 95/05996. With this closure, the pour-out spout includes an inner thread, in which the cutting element with an outer thread is mounted. The screw cap which has a peripheral lateral wall and a cover surface, on the inner side of the cover surface has at least one catch which on screwing open cooperates with a catch on the inner wall of the cutting element and then screws the cutting element downwards while the screw cap is screwed away upwards. Here too, the cutting element includes a multitude of perforating teeth which also all act simultaneously upon the packaging foil. Here too, a very large force is required, in order to carry out the opening, wherein here however one requires less force due to a significantly longer screw path. Despite this, it could initially be hardly realized for such a packaging foil to be opened, in particular if the so-called composite foils consist of a plurality of layers of plastic, cardboard, aluminium and once again plastic. Accordingly, it is envisioned to provide the packaging with a punched opening and bonding or welding this opening with a thin foil which can be easily cut open. Such solutions of course are expensive and complicated, and have the great disadvantage that the closures must be welded on in a very precise manner with regard to location, so that only the applied patches need to be severed and that the cutting element does not partially also need to sever the composite foil of the packaging. 
         [0007]    Although one has then alternatively incorporated notches into such composite foils, wherein these notches only went down to the barrier layer, so that the cutting element only needed to sever this barrier layer and the plastic foil lying therebelow, however, clearly this solution once again demands a significantly greater precision of the assembly of the plastic closure onto the packaging. 
         [0008]    A further variant is known from PCT Publication WO 2004/000667. Here, the advance of the cutting element in a first step is effected in a purely translatory manner by way of a drive, as is already known from the mentioned European Patent Reference EP0328652, and on reaching its deepest position, the cutting element from then on only rotates. 
         [0009]    Whereas initially and particularly in the context of so-called cardboard composite packaging, one operated with a multitude of perforating teeth, later one has predominantly departed from this approach. One main reason for this multitude of perforating teeth is to be seen in the fact that the cardboard layer of such packaging requires a relatively high force, in order to be pierced. The multitude of teeth then indeed no longer effects a cutting, but more of a sawing. 
         [0010]    The structure of such cardboard composite foils however has been changed over the years. One the one hand the cardboard layer has become increasingly thinner, and on the other hand several different layers of plastics have been applied, which in principle have again and again placed different demands upon the cutting element. Accordingly, a multitude of patent applications concern themselves with the shape and the arrangement of the perforating teeth and cutting teeth. Typical examples of such designs for example are to be deduced from PCT Publication WO 2004/083055 or European Patent Reference EP 1533240. An even more complex arrangement is shown for example in European Patent Reference EP 1795456. A reason for the many embodiments, as already mentioned, are the different types packaging foils, wherein in particular bag pouches (tubular bags) which have recently become widespread on the market and which are purely of plastic composite foils are a reason. Whereas the perforation is effected relatively reliably with only one or few perforating teeth in many cases, the subsequent cutting activity however is much more of a problem. These two different activities specifically, during the perforation, necessitate a relatively high force with a simultaneously low relative movement, whereas subsequently with the cutting procedure, a significantly reduced force with as large as possible a relative movement of the cutting edge relative to the foil to be severed is necessary. Here, no difference is made with the plastic closures which are obtainable on the market. 
         [0011]    Also, it has been found that with self-opening plastic closures with a rotating cutting element, the foil to be cut, on account of its high elasticity as is practically the case of all polyethylene, leads to the material being drawn out and simultaneously accumulating on the cutting edge in the rotation direction and thus practically rendering the cutting edge ineffective. This then either leads to an incomplete line of cut or to an uncontrolled tearing of the packaging foil. This only partly opened container then only allows for a poor emptying. 
         [0012]    It is thus one object of this invention to provide a self-opening plastic closure of the initially mentioned type, which can be actuated with a different force in dependence on the advance path, in order to master the problems which have been discussed. 
       SUMMARY OF THE INVENTION 
       [0013]    The above object and others are achieved by a self-opening plastic closure as described in this specification and in the claims, wherein envisaged means include a first and a second advance mechanism which engage one after the other and which effect different axial advance paths per revolution. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Further advantageous embodiments of the subject matter of this invention are discussed and deduced in view of the following description and the drawings, wherein: 
           [0015]      FIG. 1  shows a perspective view of an assembled, self-opening plastic closure, in a view from above; 
           [0016]      FIG. 2  shows a view onto a lower side of the plastic closure of  FIG. 1 ; 
           [0017]      FIG. 3  shows a screw cap of the self-opening plastic closure, in an axial vertical section; 
           [0018]      FIG. 4  shows a perspective view onto the lower side; 
           [0019]      FIG. 5  shows an axial vertical section taken through the pour-out spout; 
           [0020]      FIG. 6  shows a perspective view of the pour-out spout of  FIG. 5 ; 
           [0021]      FIG. 7  shows the cutting element in a perspective view; 
           [0022]      FIGS. 8 and 9  show cutting elements and the pour-out spout manufactured as one piece, together before applying the screw cap, in two different perspective views; and 
           [0023]      FIGS. 10-13  show the assembled, self-opening plastic closure, in each case in a diametrical section, at different stages of opening. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    One possible design of the self-opening plastic closure according to the invention and which in its entirety is indicated at element reference numeral  1  is perspectively shown in  FIG. 1 . In this view, one can practically only recognize the screw cap  2  and that part of the pour-out spout  3  which is not covered by the screw cap. This non-covered part of the pour-out spout  3  is practically only the peripheral flange  31  at the end. From the outside, on the screw cap  2 , one can recognize its peripheral lateral wall  20 , on whose lower end a guarantee strip  22  is integrally formed via suitable predetermined breakage bridges which are not visible here. The peripheral lateral wall  20  carries the upper cover surface  21 . A multitude of gripping ribs  29  which increase the gripping ability for the user on handling the screw cap are incorporated at the outside on the lateral wall  20 . 
         [0025]    The same, self-opening plastic closure  1  is represented obliquely from below in the assembled condition in  FIG. 2 . In the position shown here, the self-opening plastic closure  1  is represented in an intermediate position, with which the cutting element  4  with the perforating teeth arranged thereon is represented already projecting slightly out of the pour-out spout  2 , and the cutting element  4  is therefore at least partly visible. The pour-out spout  3  from now on is partly visible from the lower side, so that one now recognizes an energy directing rib  32  on this lower side. The design of the energy directing rib is represented here as a single, peripheral rib, but other design forms or shapes of such energy directing ribs  32  are known, and their design is accordingly adapted to the weld connection which is to be formed, and to the material pairing. 
         [0026]    The three parts which form the self-opening plastic closure are hereinafter described individually and their interaction explained afterwards. The screw cap  2  in the  FIGS. 3 and 4  is represented on its own. As every screw cap, this includes the already mentioned lateral wall (skirt)  20  and the cover surface  21  terminating the screw cap. The likewise already mentioned guarantee strip  22  is integrally formed here via predetermined breakage bridges not specially shown here, below the lateral wall in an aligned manner. Here, one can recognize the inner thread  23  on the lateral wall  20 , in particular in the sectioned view according to  FIG. 3 . This inner thread  23  serves for interacting with an outer thread on the pour-out spout  3 . A first annular wall  24  can be recognized in this sectioned drawing and this in this sectioned drawing has a different height. The first annular wall  24  in this figure at the right side of the middle axis is higher than on the left of the middle axis. The first annular wall  24  in this embodiment is completely peripheral and runs from a lowest point to the highest point, wherein the lowest point represents the starting point on opening for the first time, and the highest point corresponds to an end point after a rotation of 360°, wherein this represents the end point of the advance path of a first advance mechanism. 
         [0027]    The ramp-like first annular wall  24  has a sliding surface  25  which points away from the cover surface  21 . This sliding surface  25  then cooperates with a second sliding surface of a first advance mechanism, wherein this will be dealt with later. A second annular wall  26  is integrally formed on the lower side of the cover surface  21 , concentrically to the first annular wall  24 , offset inwards. This second annular wall  26  has the same height over its entire periphery. The axial length of the second annular wall  26  here is larger than the axial length of the lateral wall  20 . This is thus coherent so that the screw cap  2  in the assembled condition is held with its guarantee strip  22  via the flange  31  of the pour-out spout and distanced to this. An outer thread  27  is integrally formed on the outer side of this second annular wall  26 . This outer thread  27  forms part of a second advance mechanism. 
         [0028]    In principle, four concentric annular walls are integrally formed below the cover surface  21 , wherein the outer annular wall represents the lateral wall  20  and the innermost annular wall forms the so-called second annular wall  26 . Between the second annular wall  26  and the lateral wall  20 , from the inside to the outside follows firstly the first annular wall  24  and thereafter an annular wall forming a so-called sealing olive  28  which in the closed condition of the closure after opening for the first time comes to bear on the inner side of the pour-out spout in a sealing manner. The packaging foil is still closed in the assembled condition before opening for the first time, and the sealing function of the sealing olive  28  is not yet necessary. 
         [0029]    The pour-out spout  3  is shown on its own in each of the  FIGS. 5 and 6 , wherein  FIG. 5  shows a diametrical section and  FIG. 6  a perspective view, viewed from above into the pour-out spout. The pour-out spout  3  includes a cylindrical pour-out  30  of the one lower, edge-side peripheral flange  31 . This flange  31  comprises the mentioned energy directing rib  32  on its lower side serving for being attached onto a packaging receptacle for this. Basically, the flange can be bonded on such a packaging, wherein this is particularly the case with so-called brik packaging, which include multi-layered packaging foils which comprise a cardboard layer, single-layer or multi-layer plastic and at least one barrier layer. The pour-out spout, and thus the complete, self-opening plastic closure can also be welded on such a packaging foil, in particular if the outermost layer of the packaging foil is a plastic layer. Thus, here it is mostly only a welding and hardly a bonding which is considered if the self-opening plastic closure  1  is attached onto a bag pouch which mostly consists of a complex, multi-layered plastic foil with a barrier layer. An axially running guide rib  34  can be recognized on the inner side of the cylindrical pour-out  30 . This axial guide rib runs from approximately the upper edge of the cylindrical pour-out  30  to the lower edge of the pour-out  30 . This axial guide rib  34  serves for the secure axial guiding of the cutting element  4  which is yet to be described, within the cylindrical pour-out  30  of the pour-out spout  3 . Moreover, several detent lobes  35  are arranged on the inner wall of the cylindrical pour-out  30  in the lower region relative close to the plane which defines the peripheral flange  31 . Actually, this is practically two detent lobes  35  which are arranged directly above one another. These serve for holding the cutting element in a defined lowermost position. Moreover, several separated predetermined breakage bridge parts  36  can be likewise recognized on the inner wall of the cylindrical pour-out  30  in the upper quarter which is discussed in more detail later. The abutment ribs  37  which are attached on the outer side of the cylindrical pour-out  30  and which extend down to the peripheral flange  32  serve for interacting with the guarantee strip. Finally, in  FIG. 6  one yet recognizes a notch which is recessed on the outer periphery of the flange  31  and which forms an orientation notch  38  which merely serves for the orientation of the different parts in an assembly plant. 
         [0030]    The cutting element is shown on its own in a perspective view in  FIG. 7  and it comprises a cylinder wall  40  whose upper edge is designed as a ramp-like face wall  41 . This ramp-like face wall with regard to length and gradient is designed the same as the ramp-like annular wall  24  of the screw cap  2 . The ramp-like face wall  41  comprises a sliding surface  42  which in the assembled condition of the self-opening plastic closures  1  lies on the sliding surface  25  of the first ramp-like annular wall  24 . Here, several perforating teeth  43  are integrally formed on this edge in the axial direction of the sliding surface  42 . Each perforating tooth  43  is delimited by perforating edges  44  and together they enclose an acute angle. Cutting edges  45  are subsequent to these perforation edges  44 , at both sides. Two cutting edges  45  which are directed to the same perforating tooth  43  in each case together enclose an obtuse angle. The perforating teeth  43  with the acute angle which the perforating edges  44  enclose, only execute a small cutting function, but practically carry out only a piecing function, in the case of an axial movement. The subsequent cutting edges  45  which run in a relatively shallow manner, with the continued, purely translatory advance of the cutting element which is effected in the axial direction and in the direction of the packaging foil now execute a significantly greater relative movement, with regard to the peripheral line per advance path section. The cutting movement is thus effected immediately after the perforation of the packaging foil with the second advance mechanism. Trials have shown that from now on, the cutting movement immediately continues the incisions which arise on perforation and are in the running direction of the perforating edges, into a cutting line. 
         [0031]    Reinforcement ribs  491  which extend from a peripheral collar  47  to as closely as possible to the tip of the respective perforating tooth  43  are integrally formed on the outer side of the cylinder wall  40  of the cutting element  4 . The peripheral collar  47  runs in a plane perpendicular to the middle axis of the cutting element. The upper edge of the peripheral collar  47  is arranged at the height of the lowermost point of the ramp-like face wall or sliding surface  42 . The peripheral collar  47  comprises a guide recess  49 , at least at those locations, at which the axial guide rib  34  is arranged in the pour-out spout. Also, several separated predetermined breakage bridges  48  which before the assembly connect the cutting element  4  to the pour-out spout  3 , are to be recognized on the outer side of the peripheral collar  47 . These separated predetermined breakage bridges  48  are connected to the separated predetermined breakage bridges  36  before assembly. 
         [0032]    The cutting element  4  and the pour-out spout  3  together form a single-piece construction unit  70  which in the  FIGS. 8 and 9  is shown in a perspective view with different viewing angles in each case. 
         [0033]    The mentioned orientation notch  38  in the flange  31  of the pour-out part  3  is finally of significance, since the pour-out part  3  and the cutting element  4  are preferably manufactured as a single-part unit  70 . The effort on production and assembly is thus reduced. The single-part unit  70  is realized such that the cutting element  4  lies completely within the pour-out  30  of the pour-out spout  3 . In this position, the highest point of the ramp-like face wall  41  of the cutting element  4  at least approximately lies in the plane which is spanned by the upper edge  39  of the cylindrical pour-out  30 . 
         [0034]    Now, on assembly, the screw cap  2  is placed onto the single-part unit  70 , wherein the screw cap is aligned so that the highest point  493  of the ramp-like face wall  41  comes to bear on that point which corresponds to the point which lies closest to the cover surface  21  on the first ramp-like annular wall  24  of the screw cap  2 . On axially pushing together, preferably the predetermined breakage bridges between the peripheral collar  47  and the inner wall of the pour-out  30  are separated preferably at the last moment of the pushing-together, so that only the separated predetermined breakage bridges  36  and  48  continue to be present. 
         [0035]    The cutting element  4  is simultaneously moved slightly axially downwards, so that the point of the cutting element  4  which is lowermost in the axial direction, specifically the tips of the perforating teeth  43  is still above the plane which defines the lower side of the flange  31 . It is thus ensured that the plastic closure  1  does not lie on the packaging foil of the receptacle, on which it is to be fastened, already when welding on the assembled, self-opening plastic closure  1 . This position is now represented in  FIG. 10  in a diametrical section. This position shows the self-opening plastic closure  1  according to this invention, in the assembled position before opening for the first time. The predetermined breakage locations between the screw cap  2  and the guarantee strip  22  which is integrally formed thereon are still intact, but since the diametrical section does not run through a predetermined breakage bridge, this cannot be recognized in the figure. The first advance mechanism  50  is in its starting position in this position. This first advance mechanism  50 , as mentioned, includes the first ramp-like annular wall  24  with its sliding surface  25 , wherein its sliding surface  25  lies on the sliding surface  42  of the annular face wall  41  of the cutting element  40  over the entire periphery. 
         [0036]    The screw cap  2  is now represented rotated by 360° in  FIG. 11 . On the left side one now recognizes the ramp-like face wall  41  which is practically at the highest point, whereas the highest location of the ramp-like annular wall  24  has just been exceeded and therefore is now only represented in a dotted manner. The opposite position on the right side shows the ramp-like annular wall  24  which here is only half as high, since the sliding surface  42  on this side has already moved by just as much downwards. 
         [0037]    The second advance mechanism  60  now assumes its function in this position, in which the first advance mechanism has now reached its maximum advance path. As is evident on the right as well as left of the middle axis, this second advance mechanism  60 , including the outer thread  27  on the second annular wall  26  is meshed with the inner thread  492  on the cylinder wall  40  of the cutting element  4 . In this position, the first advance mechanism  50  as described in  FIG. 10  has now moved the cutting element  4  already so far downwards in the direction of the flange, that the perforating teeth  43  lie below the plane which is spanned by the flange. The perforating teeth  43  have already perforated the closure foil in the case that the self-opening plastic closure is welded on a packaging foil. 
         [0038]    If the screw cap  2  is moved by a further complete revolution, then the cutting element  4  is once again moved further in the direction of the flange  31  and not only the perforating tooth with its perforating edges  44 , but also the adjacent cutting edges  45  just as the fold-over edge  46  now lie below the plane spanned by the peripheral flange, and the packaging on which the self-opening plastic closure  1  is attached, is now completely cut open and only continues to be connected to the packaging in the region of or near the fold-over edge  46 . The cut-open packaging foil is folded over to outside the region of the pour-out  30 . In the shown position, the inner thread  23  is connected to the outer thread  33  of the pour-out spout, as also the outer thread  27  on the second annular wall  26  is still meshed with the inner thread  492  of the cutting element  4 . 
         [0039]    If one now screws the screw cap  2  again by half a revolution, then the position shown in  FIG. 13  is reached. The inner thread  492  is no longer meshed with the outer thread  27  on the second annular wall  26 . However, on the left side in this figure, one simultaneously recognizes that the peripheral collar  47  on the cutting element  4  is snapped in with the detent lobes  35  on the inner side of the pour-out  30 . With this, the cutting element  4  now remains in this position, even if the screw cap  2  is still completely screwed off from the pour-out spout  3 . After one has removed a share of the contents out of the packaging and screwed the screw cap  2  back on, then with each opening and closing procedure, it is now only the screw cap  2  which moves, while the cutting element  4  remains in the unchanged position. 
         [0040]    As previously mentioned, only a preferred embodiment is shown in the drawing. Further embodiments which are not described here are also possible without departing from the inventive concept. Thus of course all  3  components of the self-opening plastic closure  1 , specifically the screw cap  2 , the pour-out spout  3  and the cutting element  4  can all be manufactured separately. Here too, the described sequence of the first and second advance mechanism  50 ,  60  can of course be changed. In other words, the first annular wall can be designed as a normal cylindrical annular wall and be provided with suitable threads, whereas the second annular wall is then designed as a ramp-like annular wall. This second annular wall would then need to interact with the ramp-like face wall of the cutting element. Although this solution is of course also conceivable, the representation of this solution however has been omitted, and this variant is less preferred compared to the represented embodiment, because such a variant reduces the diameter of the cutting element and accordingly, in order to obtain the same opening, the whole self-opening plastic closure would need to be designed larger, which here would entail an increased material consumption. 
         [0041]    Apart from the explicitly described solution and the variants mentioned above, it is possible to realize the first as well as the second advance mechanism both with a thread or both with advance ramps. These with regard to height merely need to be arranged so that both advance mechanisms cannot be engaged simultaneously. 
         [0042]    Also, the first advance mechanism  50 , instead of extending over  360 ° as shown, can be also designed from two ramp-like sections extending over  180 ° . This leads to a symmetrical force transmission, wherein the ratio of the advance path per revolution increases, just as the necessary force effort on opening for the first time. 
         [0043]    Instead of the variant with three perforating teeth which is shown here, also only one or two perforating teeth or more than three perforating teeth can be present. This is made dependent on the diameter of the self-opening plastic closure  1 . If one provides only one perforating tooth  43 , then the adjacent cutting edges  45  extend in a gapless manner about at least two thirds of the periphery. The fold-over edge  46  then lies diametrically opposite the perforating tooth  43 .