Abstract:
A pouring nozzle with a flange and an internal thread and an external thread, and also a cutting element having an upper rim and a lower rim formed with teeth. A screw cap with catches acts on catches of the cutting element. To make fitting easier, the cutting element and the pouring nozzle are produced as a one-piece semifinished product, wherein the cutting element is connected to the lower rim by weakened bridges so that the lower rim of the cutting element lies in a plane with the upper rim of the pouring nozzle and the teeth are protected in the pouring nozzle. This structural design allows an easy fitting which also reduces the reject rate.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a closable opening device for a sealed packaging, which includes a flowable medium, wherein the device encompasses a pouring nozzle with a flange, having an internal thread and an external thread, as well as a cylindrical cutting element, which has an upper rim, which defines a planar surface. The lower rim has a tooth or a plurality of teeth, and an internal jacket surface has catches, which act in a radial direction and which interact with catches in a screw cap so that the cutting element pierces the packaging in a screw motion, wherein the pouring nozzle with the flange and the cylindrical cutting element are produced as a one-piece semifinished product. 
     2. Discussion of Related Art 
     A closable opening device of the afore-mentioned type is taught by European Patent Reference EP-A-1,088,764. A principle, which is common in closure technology, wherein multi-part closures are produced so that two parts are arranged on top of one another and are injection molded in one piece to be connected to one another via predetermined breaking points. In this connection, the expenditure of tools is reduced because the fitting is simplified, and because the parts connected to one another via predetermined breaking points are arranged in their accurately aligned relative position to one another and must thus only be pushed together. This sufficiently known technology has also been used for the closures, which are of interest, and is also taught by European Patent Reference EP-A-1,084,060, for example. The opening device disclosed differs from the former opening device taught by European Patent Reference EP-A-1,088,764 because the cutting element does not encompass a planar surface at its upper end, but an inclined surface, which bears on a similarly inclined opposite surface in response to the initial actuation of the closing device and which exerts a straight purely transversal force acting at right angles on the packaging to be pierced. This type of motion is in contrast to the type of motion according to European Patent Reference EP-A-1,088,764, which is of interest, where the cutting element is moved through the packaging in a screw motion. 
     Both documents disclose a semifinished product, which shows a one-piece production of a pouring nozzle including a flange together with a cylindrical cutting element. The cutting element according to European Patent Reference EP-A-1,084,060 does not have a planar surface, neither at the upper nor at the lower rim, which is suitable for being connected to an upper or a lower rim of the pouring nozzle in a revolving manner. A solution is thus disclosed in which the cutting element is produced in an intermediate layer within the pouring nozzle via predetermined breaking points produced as a semifinished product, to be connected to the lower rim of the pouring nozzle via predetermined breaking points. 
     However, the prefitting, where the cutting element must be inserted into the pouring nozzle, is not as trivial in both of the solutions as it may appear. The mentioned packaging made of laminate, onto which the closing devices, which are of interest herein, are mounted, include at least one plastic film layer, which is difficult to cut through because the material is very tough and must be pierced. This requires for the teeth or for at least the one tooth to be correspondingly sharp and to encompass a sufficient solidity. If the pouring nozzle and the cutting element are simply be pushed together without corresponding specific arrangements by pressure applied from the top and the bottom, the highly delicate teeth would bend, break or would at least become blunt. Consequently, the mode of operation of the opening device is no longer guaranteed. To avoid this, correspondingly complicated fitting devices are used, in which the semifinished products are introduced in an accurately positioned manner and are pushed together only thereafter. Such a fitting is not only correspondingly expensive in terms of equipment, but the fitting speed is relatively slow for a bulk material and causes a large amount of rejects. 
     SUMMARY OF THE INVENTION 
     It is one object of this invention to provide a closable opening device of the afore-mentioned type but wherein a semifinished product is used, which can be fitted in a considerably simpler and more cost-efficient manner without having to affect the teeth. 
     It is another object of this invention to provide a method by which the semifinished product of the newly created opening device can be fitted in a particularly cost-efficient manner and with high speed. This object is solved by a method having features described in this specification and in the claims. 
     The seemingly trivial solution of this invention overcomes a preconception of the person of skill in the art. Until now, experts have considered the solution chosen herein, where the cutting element is injection molded with its lower rim to the upper rim of the pouring nozzle via predetermined breaking points, to be unsuitable, because the upper rim of the pouring nozzle cooperates together with a ring-shaped sealing bead at the interior of the cap. The mounting of predetermined breaking points in this region was considered unusable, because this produces defects at the upper rim of the pouring nozzle and experts were convinced that the opening device, which is of interest herein, would no longer be closable to thus form a seal. However, tests have shown that such a solution can be realized without creating hereby an opening device, which is leaky when in a closed state. The residual appendages remaining at the pouring nozzle are so small that the seal is not influenced through this because the predetermined breaking points are designed as discussed in this specification and in the claims. However, this is not a mandatory prerequisite for realizing this invention, but only represents an optimization, while another solution would be for the ring-shaped sealing wall including the revolving sealing bead integrally molded thereon to be designed as slightly longer so that it penetrates further into the spout of the pouring nozzle when in the closed state. Thus, the cutting element should be pushed slightly deeper into the pouring nozzle, such as by a method as discussed in this specification and in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       One exemplary embodiment of this invention is illustrated in the attached drawings and the design thereof as well as the method according to this invention is explained in view of the description below, wherein: 
         FIG. 1  shows a vertical sectional view taken through a semifinished product in a production facility in which the cutting element is held above the pouring nozzle via predermined breaking points; 
         FIG. 2  shows the semifinished product in a fitted state; 
         FIG. 3  shows a closed opening device in a state prior to the initial opening, again in a vertical view; and 
         FIG. 4  shows diagrammatically, in a simplified manner, a fitting station which operates according to the method of this invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 3 , the main components of the opening device are collectively characterized with element reference numeral  1 . The opening device encompasses the three main components, a pouring nozzle  2  as well as a cutting element  3  supported therein in a movable manner and a cap  4 , which close the opening device. The two main components  2  and  3 , namely the pouring nozzle and the cutting element, are produced in one piece in terms of production and form a semifinished product, which is characterized with element reference numeral  5  and which is shown in  FIG. 1  on its own in the production position. 
     The semifinished product  5  including the pouring nozzle  2  and the cutting element  3 , facilitates the fitting of these two parts and also the production of a semifinished product which considerably reduces the tool costs. Because it is not necessary to produce two individual parts, the machine costs are also reduced. 
     The pouring nozzle  2  is formed by a cylindrical pipe section  20 , which encompasses a terminal flange  21  at its lower end. The cylindrical pipe section  20  has an external thread  22  and an internal thread  23 . The external thread  22  can be designed as a so-called fine thread, wherein the cross section of the thread encompasses a rounded shape. This fine thread has the advantage that a cap  4 , which is to be placed thereon, can be pushed open in a ratchet-like manner with a relatively small effort, wherein the appropriate internal thread of the cap slides over the external thread  22 . It is possible with this to fit the cap without performing a rotary motion, which is necessary because the cap itself encompasses an interact with the cutting element  3  so that a twist of the cap causes a rotary motion of the cutting element  2  in the opposite direction. 
     Provision is made for the flange  21  but below the external thread  22  for one or a plurality of separating agents  24 , which have the shape of fingers directed in a radially outward direction. In the fitted state of the opening device, the finger-shaped separating agents  24  engage between predetermined breaking points below the lower rim of the cap  4 , wherein the predetermined breaking points hold a tamper-proof seal, which is integrally molded at the lower rim of the cap  4 . In response to the initial actuation of the opening device  1 , the separating agents  24  shear the predetermined breaking points from the cap  4  and thus separate the tamper-proof seal from the cap  4 . The upper rim of the pouring flange  25  defines a planar surface, which runs parallel to the flange  21 . The interior thread  23  at the pouring nozzle  2  encompasses a considerably greater incline than the fine thread  22  at the outside of the pouring nozzle  2 . The cross section of this internal thread is trapezoidal. With this trapezoidal shape, the cutting element  3  can be pushed into the pouring nozzle  2  with a reduced resistance without destroying the threads. 
     As a whole, the cutting element is characterized with element reference numeral  3  which encompasses a cylindrical tube section  30 , into which an external thread  31  is inserted. The shape of the external thread  31  is matched to the internal thread  23  of the pouring nozzle  2  and meshes with the internal thread in response to the initial actuation of the opening device. The cylindrical pipe section  30  encompasses an upper rim  32 , which defines a planar surface, which in turn runs parallel to the plane defined by the flange  21 . The lower rim of the cutting element  3  is characterized with element reference numeral  33 . In the production facility of the semifinished product  5 , the lower rim  33  is located at least approximately in the region of or near the upper rim  25  of the pouring nozzle  2  and is connected in this state to the pouring nozzle  2  in one piece. The connection establishes a plurality of weakened bridges  34 . Only one weakened bridge  34  is shown in  FIG. 1 , because the weakened bridges  34  in this case are not mounted to be located diametrically across from one another. However, this would also be a possible embodiment. Sensibly, the weakened bridges  34  are arranged evenly distributed across the periphery, wherein the number can be even or uneven. In the instant case, the number is assumed to be uneven, which is why a weakened bridge  34 , which is located diametrically opposite thereto, is not visible. The cutting element  3  has a random number of teeth  35 , which can be arranged to be distributed across the periphery in an even or uneven manner. The teeth  35  have a sharp point  36 , which serves the piercing of the packaging and corresponding cutting edges  37  that follow, which are capable of cutting the pierced packaging film. The teeth  35  are located on an annulus, which is offset inwardly as compared to the cylindrical pipe section  30  by virtually at least half of the wall thickness of the cylindrical pipe section  30 . The result is a revolving shoulder  38 , which protrudes outwardly. In the instant case, the revolving shoulder  38  forms the lower rim  33  of the cylindrical pipe section  33  of the cutting element  3 . 
     With this projection  38 , the weakened bridges  34  can be designed very short and small. The distance between the lower rim  33  of the cutting element  3  and the upper rim  25  of the cylindrical pipe section  20  of the pouring nozzle  2  can thus virtually be reduced to the size of the thread height of the internal thread  23 . Due to the annulus comprising the teeth  35 , which is repositioned to the inside, a sufficient tool wall remains between the teeth  35  and the interior surface of the cylindrical pipe section  20  of the pouring nozzle  2 , so that the injection molding tool is not damaged by being removed from the mold and can also have sufficient cooling. 
     Finally, the cutting element  3  encompasses at least one catch  39 , which runs from the upper rim  32  of the cutting element in axial direction downwards and which is directed at least approximately towards the center. The catch  39 , which substantially has the shape of a longitudinal rib, is sensibly arranged so that it extends from the upper rim  32  to the point  36  of a tooth  35 . Due to the fact that only one such catch is required, the catches are not visible on all of the teeth. 
     With reference to the description of the third main component of the opening device  1 , the cap  4 , reference is made to  FIG. 3 . In this view, the opening device  1  is illustrated in a completely fitted state prior to the initial opening. The cap  4  has a cover surface  40 , surrounded by a marginal revolving jacket wall  41 . On the outside, the jacket wall  41  encompasses chamfers  42 , which increase the grip of the cap  4 . On the jacket interior, a thread  43  is mounted, which is designed as a fine thread  43  meshes with the external thread  22  of the pouring nozzle  2 . On the lower side of the cover surface  40 , a revolving annular bead  44  is available, which can be mounted on the exterior of a ring wall  45 . The ring wall  45  runs concentrically to the jacket wall  41 . Furthermore, at least one catch  46  is integrally molded on the lower side of the cover surface  40  of the cap  4 . The at least one catch  46  is directed or protrudes at right angles from the cover surface axially downwards and also runs slightly in the direction of the center. The catch  46  is integrally designed on an interior ring wall  47  as an extension. The catch  46  interacts with the catch  39  at the cutting element  3 . 
     Also, a tamper-proof seal  48 , which is connected to the lower edge of the jacket wall  41  via weakened bridges  49 , is integrally molded on the cap  4 . The previously-mentioned separating agents  24  reach between two adjacent weakened bridges  49  between the lower edge of the jacket wall and the upper edge of the tamper-proof seal through the corresponding gap. 
     The semifinished product illustrated in  FIG. 1  can be fitted without problems. The weakened bridges  34  will thus tear in the region of the connection point, virtually without causing a residue at the jacket wall interior surface of the cylindrical pipe section  20 , wherein the main part of the weakened bridge  34  remains in the region of or near the lower rim  33  of the cutting element  3 . They thus interfere only marginally because the external thread  31  at the cylindrical pipe section  30  and the internal thread  23  at the cylindrical pipe section  20  of the pouring nozzle  2  do not provide for a multiple use and because a potential scratching of the thread is completely unproblematic in response to the one-time use. The thread itself also does not need to be compact. Contrary thereto, as already mentioned above, the internal surface of the cylindrical pipe section  20  remains virtually undamaged so that a ring wall  45 , which dips into this region during the later use is capable to form an absolute seal with an annular bead  44 . 
     With reference to the fitting method according to this invention, reference is made to  FIG. 4 . The fitting method illustrated herein, which only shows the fitting of the semifinished product is understood to be very diagrammatic and it goes without saying that it is subject to different supplementations or changes by experts. The supply of the semifinished products is characterized with element reference numeral  50 . The semifinished products can reach directly from the injection molding machines via conveyor belts to the fitting station, which is collectively characterized with element reference numeral  500 . The semifinished products can also be supplied to the fitting station  500  by an intermediate storage. 
     The fitting station  500  comprises a first supply surface  51 , which can be designed as a conveyor belt or, as illustrated herein, as a vibrating surface. The semifinished products  5  bear on the supply surface  51  in an unsorted manner as bulk goods and are separated by the vibrating motion so that even adjacent semifinished products  5  with their flange  21  of the pouring nozzle  2  do not reach into the compression region  56  so as to be located on top of one another in an overlapping manner. In the normal case, the semifinished products will come to bear on the supply surface  51  either on their flange  21  or on the upper rim  32  of the cutting element  3 . It may happen sporadically that the semifinished products, as is indicated with  5 ′, bear on the supply surface  51  in a tilted position, wherein provision is made above the supply surface  51  for a crossing arbor  54 , which is arranged above the supply surface  51  to the extent that a semifinished product  5 ′, which is located in such an inclined manner, comes to bear on the crossing arbor  54  with its flange, whereby a torque takes effect on the semifinished product  5 ′ so that the semifinished product performs a tilting motion and comes to rest on the flange  21 . The semifinished products reach the actual compression region  56  through an inlet gap  57 . The compression region  56  is formed by a lower support conveyor belt  58  and by an upper conveyor belt, which acts as a continuous compression surface. The compression surface  52  and the lower support conveyor belt  58 , which is a part and a continuation of the supply surface  51 , merge in the compression region  56  to the extent that they are distanced from one another at the insertion side by at least the height of the semifinished product from the flange lower side  21  to the upper rim  32  of the cutting element  3 , while a distance is available at the end of the compression region  56  between the supply surface in this region and the compression surface, which corresponds to the height of the pouring nozzle  2 . The compression surface  52  and the actual belt of the conveyor belt, respectively, which forms the compression surface  52 , can be provided with a rubber-elastic support so that certain tolerances are compensated for and press the cutting element  3  into the pouring nozzle  2  with a small dipping depth. In this case, the upper rim  32  of the cutting element  3  comes to rest slightly below the upper rim  25  of the pouring nozzle  2 . Preferably, this difference is a few tenth of a millimeter. This distance can also be greater, only if these are semifinished products for relatively large opening devices. To keep the belt from avoiding the compression surface  52 , a counter compression element  53  can be mounted on the leading side of the conveyor belt on the rear side thereof. 
     For the person of skill in the art, instead of a vibrating surface, the supply surface  51  can also be designed as a conveyor belt. In this case, the lower conveyor belt, which is available in the compression region  56 , can simply be designed to extend across the entire length of the fitting station  500 . In this case, the surface also does not need to run so as to be bent, as is illustrated in the drawing. The advantage of the solution shown is that a manual engagement can take place, should a jam arise in the region of the crossing arbor  54 . Both of the parts, which formed the semifinished product, are now directed in fitted state via the guidance  60 . The fitting of the cap on the already prefitted pouring nozzles and cutting elements is performed in a next step, which, however, is no longer the object of this invention.