MXPA00004242A - Gable top container with pull tab - Google Patents

Abstract

The invention relates to a boxed end container having one end closed by a transverse ridge seal and carrying a pull tab whereby a separating force can be applied to the ridge seal of the sealed container so as to separate at least part of the ridge seal and thus open the container and allow discharge of its contents, which pull tab comprises a generally planar member having an axially extending shank member with a proximal end portion adapted to be gripped and pulled by a user and a distal end portion having foot members extending transversely to each side of thereof, the shank and foot members being substantially co-planar with one another, the pull tab being secured by the foot members externally to a wall of the container at or adjacent to the ridge seal of the container.

Description

CONTAINER WITH TOP OF GABLETE WITH LENGÜETA PARA JALAR DESCRIPTION OF THE INVENTION The present invention relates to a package, mainly a carton having a pull tab to help open the sealed end of the carton.

BACKGROUND OF THE INVENTION Many materials, especially fluids such as milk or fruit juices, liquid detergents or fabric softeners and mineral or vegetable oils and powders such as powdered detergents (for convenience collectively referred to below as fluids), are poured into sealed containers for transport and storage. Storage before use, when the container is opened and the content is downloaded. Many forms of packaging are used for this purpose, but one form is a thin-walled carton made from a thin card of material with a plastic sheet and having a generally square or rectangular cross section and a general shape similar to a ovoid or partition The contents of such a container are typically supplied to the package by an open top end of the package, the other end being closed by bending over the base portion of the side walls to form a box-shaped end for the package. When the desired amount of the material has been delivered to the package, the open top of the package is closed by forming V-shaped folds directed transversally in the upper portions of the two opposite side walls, with the vertices of the Vs facing inwards, one towards the other. This has the effect of placing the upper portions of the other two side walls of the container together to form a tent-like upper part for the container having a flange which is along the line of indentation of the V-shaped folds. The flange is then heat sealed or otherwise processed so as to secure together the opposite faces of the upper portions of the V-folds and the other side walls in a single linear transverse strip seal closure for the container , at least in a main portion of the container that is placed within the flat area in total cross-section of the container. The sealed ridge is often folded downwardly through a transverse bend line that extends through approximately the midpoint of one of the tent-like top side walls, so that they conform at one end in the form of a flat box for the container. In some forms of such a closure, a tape is included, which can be reinforced with wire at the ridge line, for example during bending on the ridge material.This tape extends beyond the ends of the ridge to provide extensions which can be folded on themselves to secure the flange bent down in position by engaging the free ends of the ribbon under the lip that is formed along the edge of the box-shaped end, where the bent portion is indented V of the container wall Alternatively, the free ends of the extensions can be adhered or otherwise fixed to the side walls of the container once the flange has been folded downward to form a shaped end of box for the container For convenience, the following terms shall have the following meaning herein: containers that can be opened with an end in the form of a ca vases of the general type described above; The flange seal will be used to indicate the transverse linear seal between the opposite faces of the upper end portions of the indented and non-indented side walls of the container; the flange will be used to indicate the exposed upper edge of the flange seal or the edges of the wall material which have been joined before forming the flange seal; Flange structure will be used to indicate the structure formed by joining the upper end portions of the side walls of the container and which have been or will be fixed together by heat sealing, welding, bonding or other means between the opposite sides in the interfaces between these opposite faces to form the flange seal; Gable-shaped end will be used to indicate the structure formed at the upper end of the container by indentating the upper portions of two opposite side walls of the container to form the V-shaped folds in the flange structure; The tent-shaped end will be used to indicate the end of the container with the flange in the raised position either before or after forming the flange seal; Gable-shaped side walls will be used to indicate the upper portions, usually three tubular portions of two opposite side walls of the open end of the container which have been indented to form a V or other axial fold in the upper portion of the side wall of the container. so that the wall is collapsed laterally inward to form the gable-shaped end for the container; gable end triangles will be used to indicate the triangular-shaped walls that constitute the surfaces exposed within the gable-shaped end of the container; tent-like side walls will be used to indicate the two opposite side walls of the container which extend between the gable-shaped side walls of the gable-shaped end of the container; Wet wall will be used to indicate an inner surface of the container which is to be put in contact with the contents of the container, which includes the upper portions of such walls which are to be incorporated within the flange structure; Drywall will be used herein to indicate an outer surface of the container which is not in contact with the contents of the container that includes the upper portions of such walls which are to be incorporated within the flange structure. To open such a container that can be opened at the box end, the seal at the gable end at the interface between the opposite drywall surfaces of the V fold at one end of the linear flange seal are separated.

This forms a pair of fins on the gable end so that the plan view configuration from the top of the flange seal to the container adopts a Y-shaped configuration instead of a single-line seal. The upper edges of the fins form the upper part of the Y that remains sealed so that the container is still sealed when the flange seal adopts this configuration. The fins are then folded back to be in line with each other, i.e., so that the plan view configuration from the top of the flange seal adopts a T-shaped configuration with the fins forming the upper part of the flange. T. The free ends of the fins are then pressed inward, towards the center line of the upper part of the T to apply a force of separation to the seal at the intersection of the head and the vertical part of the T. it is intended to cause the seal between the opposing faces of the wet walls in the upper part of the container to separate at this intersection and to form an opening through which the contents of the container can be discharged. In some cases, it may be desired to bend the fins by overrunning the in-line configuration to form a Y-shaped plan that has an inverted head (the inverted Y configuration) so as to improve the separation force that is applied to the seal in the intersection before the application of pressure on the free ends of the fins. However, the seal separation in. the intersection is often incomplete and / or the fins collapse so that the user can not continue applying the separation force to the seal. Therefore, it is usually necessary for the user to insert a finger, a point, the point of a knife or other implement into the initial opening that forms at the intersection to assist in obtaining a complete separation of seal and so that the opening extends to form a spout outlet for the container.

In many cases, the initial separation of the seal between the wet walls at the intersection of the upper part and the vertical part of the T is insufficient to form an opening in which the user can insert the tip of his finger. It is then necessary for the user to pierce the material of the dry wall in the region of the intersection and to try to pull the wall outwards to cause separation of the seal at the intersection. Such separation of the seal can occur abruptly, which causes the spillage of the contents of the container and the need for such additional operations to separate the seal from the flange is inconvenient. However, these problems in forming the opening of the container, which are particularly serious for the elderly or weak, and for children, the containers that can be opened at the box-shaped end provide a simple and effective container for storage and transport of a wide range of fluids and are still widely used. Many attempts have been made to overcome these difficulties by opening such containers by incorporating pull strips or the like in the linear seal at the gable end of the container, see for example, US Pat. Nos. 4,883,222, 4,821,950 and 4,874,126, European application No. 0 695 264A and British patent application No. 2,010,212A. However, in all cases, one or more additional components must be incorporated into the flange structure. This introduces problems in the precise positioning of this component and its fixation in position. It also introduces an additional member between the walls which are to be sealed together to form the flange seal, which may result in a weakening of the seal in this area, with the concomitant risk of premature failure of the flange seal. In addition, the material from which the additional component is often formed, often experiences thermal fusion with the flange seal that is formed by a heat sealing process. This can cause the additional component to merge together and / or expose it to the container wall surfaces, which causes the component to break violently when pulled and / or to generate an additional seal adjacent to the seal of the container. flange which must be separated in order to open the container. The additional component is often fixed in alignment with what is to turn the spout into the open container. The content of the container then flows over the component which may have been exposed to dust, grease or other materials and therefore causes contamination of the contents. In addition, in order to introduce additional components into the flange seal it is necessary to modify the construction of the carton, the filling and sealing processes considerably, which adds capital and operating costs necessary to implement such proposals . None of these proposals has been adopted commercially.

It has also been proposed, for example in US Pat. No. 3,520,464, PCT applications Nos. W096 / 29253 and 097/44255, and British Patent Application No. 2,253,608A ensure a pull tab or the like on one or more of the surfaces of the triangular gable end wall, of the gable-shaped end of the container. Although such a proposal can solve the problems of securing an additional component within the flange structure, such proposals have not been adopted. This is due to the failure in the anchoring of the pull tab to the container wall when tension is applied thereto to open the container, even when the flange seal is partially separated to adopt the T-shaped configuration, as It is described before. As a result, the pull tab is separated from the container before the flange seal is separated and the container remains sealed. Even if the area of the legs of the pull tab which is anchored to the wall of the container is increased, the maximum area which can be obtained is restricted by the available area of the wall or triangular walls to which the walls are attached. feet and the maximum size of the pull tab which can be accepted before it interferes with the mechanical handling of the carton during filling and transport, and the removal of the pull tab before separation of the carton occurs. flange seal. Instead of the additional components for providing the pull tab, it has been proposed, for example, by European Patent Application No. 0 087 839 A and PCT Application No. WO82 / 03370, to provide the pull tabs as axial extensions from part of the container walls. However, such extensions are usually located in a manner that will cause the pour spout of the container to open, resulting in contamination of the contents as it points outward. In addition, if such axial extensions are bent so that they are in the same plane against the outer wall of the container, so as to prevent them from sticking in the container forming or filling machinery, at least part of the extension is will be incorporated into the flange structure and merged into the flange seal as the container is sealed. This can weaken both the pull tab that breaks away from the flange seal and / or the tab fuse inside the flange seal. This can lead to additional seals that require separation in order to open the container. It has also been proposed to weaken the bonding of adhesive within the flange seal so that less force is required to separate the seal and thus open the container. For example, it has been proposed to apply an adhesive to the wet wall portions within the rim structure so that they do not adhere, or do so only weakly to each other, during the sealing operation of the container. However, the use of adhesives requires an accurate placement of the correct amount of the adhesive at the desired positions within the flange structure so that only a very weak seal forms within the gable end. This introduces additional costs and operations in the production of a sealed package and inherently presents concomitant risks that the seal may fail prematurely during storage, transport or handling by the end user. In order to reduce this risk, a heat sealing bar specially sculpted to omit sealing areas within the flange seal itself has been proposed in US Patent No. 4,946,041. However, this requires the use of complex additional thermal seals and accurate formation of unsealed areas and also presents the inherent risk of premature failure of the flange seal. It has also been proposed, for example in US Pat. No. 3,204,850 and GB Patent No. 689,204, not to form a flange seal by joining opposite faces within the flange structure., but to form a labyrinth mechanical seal when forming on the flange structure and fixing the structure bent in position by means of a wire or adhesive. Such proposals are susceptible to leakage from the container since a united seal is not formed. In addition, such proposals require the use of specialized bending equipment and can not be carried out in conventional packaging manufacturing equipment. Instead of weakening the flange seal or introducing additional components into the flange structure, it has been proposed to form actual weakening lines or cuts through the container wall and cover them with a removable cover strip, see for example the application GB No. 2,253,608A and US patents 3,456,328 and 2,687,840. The removal of the cover strip exposes the cut or weakening line which can then be separated to form an opening of the container. In a variation of such proposals, the container wall is partially cut through so that the wall can be detached at this point to form an outlet spout without the need to separate the flange seal or to form a pull tab from the container wall which can then be used to separate the flange seal, see, for example, US Pat. Nos. 2,470,199, 5,067,613 and 5,516,037. Such deliberate weakening of the container wall presents the inherent risk of premature failure of the container. However, none of the above proposals has proven to be technically or commercially viable and as a result, in commerce there is no satisfactory method for opening the gable-shaped end of a box-end package. Despite the known and widely publicized problems with the opening of a container with a box-shaped end, such containers continue to be widely used because of their simplicity, low cost and ease of production and for their general acceptance by the public.

Surprisingly, we have found that if the legs of a pull tab are fixed to the container wall and secured in a specific manner, problems due to separation of the pull tab from the container wall can be reduced before separation of the flange seal occurs.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, the present invention provides a container with a box-shaped end having a closed end by a transverse flange seal and having a pull tab, whereby a separation force can be applied to the flange seal of the container. sealed so as to separate at least part of the flange seal and therefore open the container and allow discharge of its contents, pull tab which comprises a generally planar member having a rod member extending axially with a proximal end portion adapted to be held and pulled by a user, and a distal end portion having leg members extending transversely to each side thereof, the rod and leg members are substantially coplanar to each other, the The pull tab is attached by the leg members externally to a container wall in or adjacent to the flange seal of the container, characterized in that: to. the leg members are fixed substantially symmetrically about the longitudinal axis of the rod member to a wall of the container and / or to that portion of a wall incorporated within the lip seal; and b. the pull tab has a point of rotation around which the rod member flexes with respect to the leg members when tension is applied to the proximal end of the rod member during the opening of the container, which rotation point is located longitudinally with respect to the rod member substantially in alignment with the union of the rod member and the proximal edges of the leg members; and c. the fixing of each of the leg members to the wall of the container by means of a fixing system which has an edge proximal to the point of rotation, edge which is configured so that at least a portion thereof extends perpendicular to a line extending from the edge proximal to the point of rotation, the line intersects the intermediate edge at the ends thereof. The term edge is used herein with respect to the fixing means to indicate the periphery of the fixing means extending in the plane of the container wall. Preferably, the fixing is by means of a thermal or heat seal between the surface layers of the container wall and the material of the pull tab.

Surprisingly, we have found that such thermal seals can be in the form of line seals instead of seals that extend over all of the plan areas on the opposite sides of the container wall and the leg members of the pull tab . It is more unexpected that reducing the area on which the leg member of the container wall is fixed does not weaken the attachment of the tongue to pull the container. Accordingly, the present invention also provides a container with a box-shaped end having a pull tab externally fixed to a container wall at or adjacent to the container rim structure whereby a separation force may be applied to the flange seal of the sealed container, characterized in that the distal end of the pull tab is externally fixed to an outer wall of the container and wherein the attachment of the distal end is by means of at least two attachment lines, one in each side of the longitudinal axis of the tongue of the pull tab, each of the fastening lines which have at least a portion thereof which are configured so that they extend perpendicular to a line extending from the point of rotation of the rod of the pull tab and intersecting the intermediate fixing line at the ends thereof. We believe that such configuration ensures that the portion of the attachment line is adjacent more closely to the point of rotation of the rod member and is oriented substantially at right angles to the forces transmitted from the rod member to the leg members and by it therefore acts as a stop for any separation by detachment of the fixing of the container wall. In a particularly preferred embodiment, the leg members are fixed to the wall of the container so that the fixing area for each leg extends longitudinally both above and below the point of rotation of the rod of the pull tab. We have found that such a fixation reduces the risk that the fixation will experience a progressive detachment gap as the proximal end of the pull tab rises away from the plane of the container wall and the tension applied thereto. Accordingly, the present invention also provides a container with box-shaped end of the invention, characterized in that the distal end of the pull tab is fixed to a container wall by means of a fixing area or areas, at least one is located on each side of the longitudinal axis of the tongue of the pull tab, the attachment areas extending longitudinally on either side of the pivot point of the tongue of the pull tab. Preferably, the fixing areas extend a distance d above (distally exceeding) the point of rotation, and a distance d 'below (proximally cuts to) the point of rotation and the proportion of d: d' has a value of 10: 1 to 1:10, preferably from about 1: 3 to 3: 1, and notably about 1: 1. We believe that a pull tab that has the configuration required to obtain such a form of attachment to the wall of the container is novel. Therefore, the invention also provides a pull tab for use on a container, pull tab which comprises a generally flat member having a proximal portion adapted to be held and pulled by a user, a rod member extending longitudinally and a distal portion by means of which the tongue can be attached to pull a wall of a package or a preform for use in the manufacture of a package, characterized in that the distal portion is provided with two leg members extending laterally to Each side of the longitudinal axis of the rod member, each leg member extends proximally and distally longitudinally on both sides of the pivot point of the rod member. We have also found that the provision of an area between the leg members which is not fixed to the wall of the container can be advantageous insofar as it allows the rod and the union between the rod and the leg members to rise away of the surface of the walls as the V-shaped folds occur in it, during the sealing of the container. This reduces the severity of bending which must be experienced by the pull tab and minimizes the formation of a set in the pull tab material which may affect the manner in which the pulling force applied to the proximal end of the tab for pull is transferred to the leg members. The lack of a fixation between the leg members also allows the leg members to move laterally towards each other as the pulling force is applied to the proximal end of the pull tab. This causes the leg members to apply two opposing forces acting along the line of the flange so as to develop a detachment by rotation of the flange seal. The application of such a detachment force more easily results in the separation of the flange seal compared to a cutting force. Accordingly, the present invention also provides a container with a box-shaped end having a pull tab externally fixed to a container wall or adjacent to the flange structure whereby a separation force can be applied to the flange seal of the sealed package, characterized in that the distal end of the pull tab is fixed to an external container wall and wherein the fixation of the distal end is by means of two laterally spaced portions of the distal end portion of the pull tab. an intermediate unfixed portion that is located between the fixed portions, so that the pull tab exerts two opposing forces on the flange seal portion axially in alignment with the intermediate portion that is not fixed, when the user pulls on the pull tab. The pull tab for current use comprises a rod member having a proximal end by which a user can grip and pull the tab, and a distal portion by which the rod is fixed to the container. The transverse dimension of the rod enlarges in the distal portion of the rod so as to provide laterally extending leg members which are fixed to the container. The intermediate area of the distal end of the rod may or may not be attached to the container. Typically, the leg members extend from 1 to 5 c on both sides of the tongue of the pull tab and extend at any suitable angle from the rod so as to provide a d: d 'ratio required for the attachment of the areas by which the leg members are fixed to the container wall. We have found that the included angle between the proximal edges of the leg members and the longitudinal edges of the rod member should be less than 90 °, preferably 15 to 80 ° and notably about 45 °, so that the forces exerted on the leg members when the rod is pulled by the user do not act to detach the fixing of the wall of the container. Such an angle also allows the edges of the fixing areas or lines to adopt the desired orientation within the plan area of the leg members. The longitudinal edges of the stem can intercept the line of the proximal edge of each leg member at an acute angle. However, it is preferred to provide a curved intersection extending from 1 to 5 mm from the longitudinal distance of the rod. Such curvature provides a stop for any tearing force of the tongue material to pull in its position and also allows the material of the pull tongue to deform in this area during the formation of the V-shaped folds of the gable-shaped end. of the container and also reduces the lifting of the proximal edge of the leg members and therefore reduces the detachment force acting on the attachment of the leg members to the container wall. When determining the position of the rotation point of the rod member, tolerances for such curvature need to be made. In general, we find that when designing the shape of the pull tongue it is satisfactory to determine the point of rotation which should be in the middle part between the longitudinal points along the axis of the rod member where the curvatures begin and end. . However, it will be appreciated that the point of rotation will move distally towards the end of the bend when the pull tab is raised and pulled by the user so that the point of rotation has a support position and one end in a position of use which is substantially in alignment with the distal end of the curvature. The term rotation point of the rod member is therefore considered to include both the resting and extreme use positions. A particularly preferred form of pull tab is a flat member in generally T-shape having a triangular finger ring at its proximal end joined by the rod member to a pair of generally triangular leg members which extend longitudinally for substantially the same distance on both sides of the point at which the legs meet the rod member. The opposite edges of the finger ring and the leg members are substantially parallel to each other and are inclined substantially 45 ° to the longitudinal axis of the rod member. It is also preferred to provide the proximal portion of the pull tab with a finger hole, a rib or other means during which the user can grasp the pull tab. Such pull tab forms can be made using conventional cutting, stamping or other equipment. The pull tab can be made of numerous materials, depending on the method used to fix the leg members to the container wall. Preferably, the pull tab is fixed by heat or by ultrasonic welding and the pull tab is made of a material which is readily welded to the container wall. Therefore, the pull tab can be cut from a polyethylene sheet or other thermoplastic material that melts at a low temperature. 5 When the pull-tab is fixed to the container wall by an adhesive which melts heat, a pressure sensitive or adhesive tape with adhesive on both sides adhesive, may be desired to subject the polyethylene to corona discharge type or other treatment to make it receptive for the adhesive. Without However, we have found that polyethylene may not have the tensile strength necessary to apply sufficient force to the seal of the package without tearing itself. A particularly preferred material is a laminate material having an exposed face formed of a polyethylene which can be thermally bonded to the material of the container wall, and one or more layers of a highly stress-resistant material, for example a polyester. It is particularly preferred that the other exposed face of the laminate is formed of a material which has a melting point greater than, and preferably at least 40 ° C higher than the melting point of the surface layer of the container wall so that this face does not melt significantly during the forming of the flange seal on the package. Polyester is particularly preferred, which has a melting temperature of about 100 ° C higher than of polyethylene. The use of such a laminated material reduces the risk that the exposed faces of the pull tab are joined together and / or to the container wall during thermal sealing of the flange seal. The pull tab can be fixed to the container at any position on a wall of the container or within the rim structure in which the fixed portions of the pull tab can be the separating force at a portion of the rim seal axially in alignment with the pull tab. However, in order that the forces generated in accordance with the tongue of the pull tab is subjected to being pulled by the user and can exert a sufficient force on the flange seal, it is preferred to secure the pull tab in the following 2.5 cm. from the flange seal legs. Therefore, the pull tab can be attached to a tent-like side wall of the end of the sealed container or to the exposed side wall of the linear flange seal. However, it is particularly preferred to secure the pull tab to a gable-shaped end wall of the container so that the container is opened in a manner similar to a conventional carton package. For convenience, the invention will be described below in terms of this preferred fixing position. The distal end of the pull tab can be incorporated within the flange structure. Since the distal portions of the pull tab are joined to opposite drywall faces of this portion of the flange seal, they do not damage the integrity of the seal between the opposing wet walls of the flange seal. However, fastening the pull tab within the flange structure can result in excessive bending of that part of the distal end of the tongue to pull into the V-fold of the flange seal. This may require provision of adhesive from another means to prevent significant adhesion of that intermediate portion of the tongue to pull the opposite portions of the ridge structure during thermal sealing of the ridge structure during closure of the container, after filling . Therefore, it is preferred that the legs extending laterally of the pull tab be attached to one or more of the gable-shaped end wall portions of the container, below the flange seal itself. The fastening can be to the central triangular portion of the gable-shaped end wall. However, this may require that the fastener be removed axially some distance from the flange seal legs and therefore that the forces generated by the pull tab do not act directly on the flange seal and its effect on the seal is reduced. of flange. Therefore, it is particularly preferred that the pull tab be attached to the triangle walls of the side roof of the gable-shaped end wall and, preferably, not to the central triangular end wall of the shaped end network. of gablete. When fixing the pull tab in this way, once the end of the linear flange seal has been separated as described above during the initial stage of opening the carton to form a seal with a plan view of T or Y, the forces applied by the pull tab The flange seal exerts a detaching action on the flange at the intersection of the vertical part and the upper part of the Y or T which causes the flange seal to easily separate at this point. A force transverse to the flange seal line is also generated, bending the gable end wall outward to form an outlet spout for the container and progressively separating the flange seal on both sides of the intersection. As a result, a pulling tab anchored in this manner is surprisingly more resistant to detachment from the container wall as compared to one anchored to the central triangle wall or within the flange seal structure, as the proposals of FIG. previous technique. Accordingly, from another aspect, the present invention provides a container with a box-shaped end of the invention, characterized in that the leg members of the pull tab are fixed to the triangular end portions in the shape of a gable end. in the form of container gable. Preferably, the distal end portion of the intermediate rod member to the leg members is not fixed to the container wall. The package can be made from a wide range of materials such as wax-coated paperboard, polymer-coated paperboard or a laminated plastic sheet material. However, the invention will be described below in terms of a conventional gable end package made of a cardboard laminated with polyethylene or other thermoplastic polymer. Such containers can be manufactured by folding and securing the appropriate opposite edges of a flat preform using conventional techniques and equipment. Although the pull tab can be applied at any suitable point during the processing of the container or its preform or during the filling and sealing of the assembled container, it is preferred to fix the tab to pull the preform before assembling the container, using a conventional technique of thermal sealing. The invention also provides a preform for use in the construction of an openable container, with a box-shaped end of the invention, preform which comprises a series of connected panels adapted to be bent and fixed to each other so that forming the container, the end portions of two of the panels are adapted to form the gable end walls of the assembled container, characterized in that on or adjacent to the terminal portion of one or more of the wall panels there is a fixed pull tab , comprising a generally planar member having a proximal end adapted to be held and pulled by a user, an axially extending rod member, and a distal end portion having leg members which extend transversely to each side of the same, pull tab which is fixed to a panel of a preform by means of a fixing element, characterized in that the means The fixation has a proximal edge edge to the point of rotation of the rod member and is configured such that at least a portion of the edge extends perpendicular to a line extending from the point of rotation to intersect the intermediate edge to the ends of the same. Preferably, each of the terminal portions of the two panels are for forming the gable end walls of the container and are provided with substantially symmetrical fold lines forming a V having its apex at or adjacent the center point of the terminal edge of the container. panel, and its base on or adjacent to the designed base of the gable end wall, so that it defines two triangular areas laterally outward, and an intermediate triangular area of the terminal portion and the leg members of the pull tab are attached to each of the triangular portions laterally outwardly of at least one of the terminal portions.

Preferably, the pull tab is located axially symmetrical about the center line of the panel and substantially in alignment with that portion of the terminal portion of the panel which will form the apex of the V-fold at the gable end of the assembled container. The pull tab can be applied to the package preform using any suitable technique, for example, a rotary or linear label application technique using adhesion welding, adhesive or other means to secure the pull tab in a position initially; and subsequently apply subsequent full thermal welding to fix the pull tab in position. However, it will usually be desired to fix the pull tab in position with a single complete weld in a single step by a process of applying and fixing the pull tab. For convenience, securing the tab for pulling the package will be described in terms of thermally welding the leg members of the tab to pull the appropriate areas of the preform from which the package is subsequently manufactured. Thermal welding is conveniently produced by a conventional thermal sealing technique. As stated in the foregoing, thermal welding may extend over the plan area of the leg member, but preferably is in the form of one or more welding lines between the leg members and the wall material of the container. The ability to use welding lines to fix the leg members to the container wall and reduce the risk of thermal damage to the pull tab and allows the required pressure to be applied for the thermal welding over small areas, which reduces the requirements of power for thermal welding. Such weld lines may be simple straight lines, continuous or discontinuous, or may form a rectangle or other shape that encompasses the non-welded area. The welds can also follow curved lines and a particularly preferred form of welding line is an arc centered on the pivot point of the pull tab, so that all the forces generated by the pulling action at the proximal end The pull tab is applied substantially perpendicular to the welding line. If desired, several lines of welds can be formed at increasing distances from the point of rotation. As indicated above, the welded areas preferably extend longitudinally both above (this is close to) and below (ie, distally of) the pivot point of the pull tab. Preferably, at least one area welded to each side of the longitudinal axis of the rod of the pull tab extends continuously from the top downward of the point of rotation and has an edge proximal to the point of rotation which is subtended over less a portion of its length at an angle included to the longitudinal axis of the rod which is from 20 to 80 °, preferably approximately 45 °. It is particularly preferred that the edges of the lines or attachment areas be adjacent and substantially parallel to the fold lines defining the boundaries between the three triangular portions of the gable-shaped end of the container so that the forces applied by the tongue of pulled act directly on the flange seal. The optimal shape of the fixation can easily be determined within the previous guide lines using simple trial and error tests. In order to assist in the separation of the flange seal, it may be preferred to provide reduced adhesion between the opposite faces of the drywalls by at least a portion, typically from 10 to 50% of the indentation of the V-folds within the seal. of flange. This can be obtained by applying an adhesive agent to selected areas of the opposite drywall which is incorporated within the flange seal. Alternatively, such weakness of the flange seal can be obtained by extending part or all of the distal end of the rod and / or the side leg members within the flange structure. However, we have found that the position of the pull tab anchor to the triangular roof of the gable end usually allows a sufficient separation force applied to the flange seal without the need for any adhesion or other weakening of the flange seal, so that the risk of premature seal separation and container failure is reduced. The above preferred form of container is easily opened by partially separating one end of the linear rim seal formed by the conventional thermal seal of the container and then applying tension to the proximal end of the pull tab. Accordingly, the invention also provides a method for opening a box-shaped end of an openable container of the invention, which method comprises separating the seal between the dry walls at that end of the flange seal of the container adjacent to the container. the tongue for pulling, or bending the ends of the flange seal, so as to form a flange seal having a curved T or Y configuration and applying tension to the proximal end of the pull tab so as to separate the seal between the wet walls of the seal, preferably at the intersection of the vertical part of the seal head configured in T or Y. We believe that, at least initially, the force applied to the wet walls of the flange seal by the pull tab is a detachment force acting along the line of the flange seal at this point. However, the force will usually also include a component normal or perpendicular to the seal line which acts at least partly upward towards the outer edge of the flange seal and acts imparting a release force upwards on the seal of flange which additionally helps the separation of the flange seal. The continuous application of tension to the pull tab causes the progressive separation of substantially the entire length of seal to form a spout outlet for the container. If desired, the container can be provided with one or more notch or fold lines which assist in the bending of the gable end walls and the associated side wall of the container to assist in the separation of the flange seal and deployment of the spout outlet of the container. Such bending or notching lines can be formed using conventional techniques and equipment. The surfaces of the spout which is contacted by the discharge of the contents of the container, are those of the wet walls which have been joined during the sealing of the container and have not been exposed to external contamination during storage and transport before opening the container. In addition, since the pull tab is externally attached to the container and is not part of the lip of the spout, the material flowing through the spout will not contact the pull tab and will therefore not be contaminated with grease, dust, etc., on the pull tab. The containers of the invention can therefore be used for the packaging of food products or other materials which require them to be handled under sterile conditions and which must be subjected to a minimum of contamination during unloading of the container. In addition, since the container and the pull tab can be manufactured without any metallic component, the containers of the invention can be heated in a microwave oven. The containers of the invention can therefore be used to contain soups or other food products which require heating before consumption. Since the containers can be opened simply and easily, the risk of splashing a hot food product on the user is reduced. Thus, the invention provides a simple and effective solution to the problem of opening a container that can be opened at one end in a box shape without the need to significantly modify the manufacturing or filling process of the container, thereby allowing the invention to be Apply to conventional equipment. Alternatively, the pull tab can be placed in an assembled or sealed container using any suitable machine that is located at the end of the assembly line, sealing or filling the container.

DESCRIPTION OF THE DRAWINGS For help in understanding the invention, a preferred form thereof will now be described by means of an illustration and with reference to the accompanying drawings, in which Figure 1 is a perspective view of the package that can be opened in a box-shaped end, in its completely closed configuration that carries a pull tab; Figures 2, 3 and 4 show the package of Figure 1 with the flange seal partially open, bent back to form the inverted Y configuration and with the separate flange seal to form the spout outlet of the container; Figure 5 shows a plan view of a preform for use in the construction of the container of Figure 1; Figure 6 shows an alternative version of the preform having additional fold lines to assist the formation of a full-length spout to the side wall of the package; Figure 7 shows the relationship of the edge of the heat sealed area securing the legs of the tongue to pull the container wall at the point of rotation of the rod member; and Figures 8 to 10 show alternative forms of line seals for use in the present invention.

DESCRIPTION OF THE PREFERRED MODALITY The package comprises a generally rectangular or square main body portion 1, a lower part has been closed by folds of conventional boxes or other means, and which contains milk, fruit juice and other fluid or a powder that can flow. The package is made of paper coated with wax or plastic or cardboard so that it can be easily bent along the notch lines or the like that form on a preform sheet from which the package is made and the configuration bent it is demanded instead by heat sealing or some other means adhering the overlapping edge portions of the assembled container. Alternatively, the package can be manufactured by blow molding or extrusion of a suitable plastic so that the package is formed as a unitary article with an open top. Either the container is made of a flat preform, which is bent and fixed in its desired erect form by thermal welding, adhesive or other fixing techniques. For convenience, the invention will be described below in terms of using a paperboard coated with polyethylene or other thermoplastic polymer as is conventionally used in the manufacture of such containers. The upper end portions of the side walls of the container have been bent over one another to form a conventional box-shaped end. In such an operation, a V-fold is formed in each of the two opposite side walls with the apex of each V directed towards the central line of the container. This has the effect of placing the upper edges of the other two side walls together, so that they form a tent-like end in the container. The upper edges of the side walls meet against each other forming a flange 2 which lies along a transverse line extending along the line of indentation of the V-bends. The edges are sealed by application of heat and pressure using a conventional heat sealing bar or the like to form a comparatively deep transverse seal seal along the flange 2. The depth of this flange seal is sufficient to incorporate the upper edges of the walls bent in V for ensure a fluid tight seal. The indented portion of the end of the container is the gabled end 3 and carries a tongue 10 for pulling. As shown in Figure 2, the wall A of the gable end has two fold lines 4 and 5 forming a triangle whose apex is the point at which the wall A is bent to form the V fold as it occurs the gable-shaped end of the container. On each side of these lines are inverted triangular areas B which are to form the faces of the gable end of the assembled container, and have their bases along the legs of the upper terminal portion of the wall A , which is incorporated within the flange seal 2. Between these triangular areas B is another inverted triangular area C. These areas can be easily seen in the preforms shown in figures 5 and 6.

A pull tab, cut from a polyethylene / polyester laminate has a ring 11 for pulling on the proximal end of the stem portion 12. Extending laterally from the rod portion are two symmetrical triangular legs 13. These are secured by means of the polyethylene layer to the triangular areas B on either side of the area C by thermal welding or by another means, for example adhesive or riveting. The fixation extends over the shaded areas shown in the drawings and it will be noted that they do not extend into the intermediate portion D of the rod between the legs 13. The central portion of the pull tab formed from the rod 12 and the ring 11 for pulling is not fixed to the wall of the container, but is free to bend away from the container during formation of the gable end for the container and during sealing of the flange seal. If desired, the proximal end of the pulling ring 11 can be welded with adhesive or temporarily fixed in some other way to the container wall for transport and storage before use. As shown in Figure 7, the rod 12 is bent around a point D when the ring 11 is pulled to pull. This point D is the point of rotation. The edge of the thermal seals between the legs 13 and the walls B proximal to the point of rotation D is located adjacent closely and substantially parallel to the fold lines 4 and 5 so that the included angle between the edge of the thermal seal and the axis The length of the tongue of the pulling tongue is approximately 45 °. A line drawn from the point of rotation D perpendicular to the edge of the thermal seal intercepts the edge between its ends and the seal acts in a way that stops or prevents the detachment of the thermal seal. The thermal seal area extends both distally surpassing as proximally close or short to the point of rotation, and the ratio of d: d 'has a value of about 1: 1. Such a container can be assembled from a preform, as shown in Figure 5, using conventional techniques and equipment. In use, the seal between the opposite drywalls along the rim 2 is separated at the end adjacent the tab 10 to pull as with a conventional container to produce a rim which has a flat T-shaped shape, as shown in figure 2, which has a vertical part U and fins towards the upper part of the T-shape. The seal between the opposing wet walls of the fins is still intact and in this way the container remains sealed. If desired, the flange of the head of the part T is bent backwards, as shown in figure 3, to form a planar shape and inverted in the flange. The user then pulls on the ring 11 to cause the flange seal at the intersection X of the vertical part U and the fins to separate and form the spout 15 for pouring. The pull tab 10 remains below the lip of the spout and is not in contact with the contents of the container, whereby the risk of contamination of the contents as it is discharged is reduced. As shown in Figure 4, the spout 15 is comparatively short. Therefore, it may be desired to add additional bending lines 20 as shown in Figure 6, which extend from the apex of area C to the base of the container to allow the sidewall of the container to curve outward to form a spout that extends the full length of the container, so it helps produce a uniform flow of material from the container. Due to the position and orientation of the thermal seals, the legs 13 are not easily separated from the wall material and the user in this way can exert considerable force on the flange seal without the legs detaching from the wall. In contrast, when the pull tab is in the form of a T so that the thermal seals that are attached to the head of the T with the wall of the container still do not extend proximally to the point of rotation D, the pull tab is easily detached from the wall before the flange seal is separated. As shown in FIG. 8, the legs 13 are fixed to the wall by the seals 20 in line and the lines E from the point of rotation perpendicular to the line of the thermal seal interspersed with the intermediate seal line at their ends. Such a form of attachment ensures that the pull tab remains fixed to the container wall while separating the flange seal. Figure 9 shows a set of line seals 30 and 31 that conform to the contour shape of the solid thermal seal used in Figure 1; Figure 10 shows an arched line of a thermal seal. Also shown in dashed lines in FIG. 10 is a shape of the legs 13 which have been cut and detached to conform to the arcuate shape of the thermal seal. All of these variations of the thermal seal of Figure 8 provide good levels of bonding of the tongue to pull the container wall.

Claims (20)

1. A container with a box-shaped end, having one end closed by a transverse flange seal and having a pull tab, whereby a separation force can be applied to the flange seal of the sealed container so as to separate at least part of the flange seal and therefore opens the container and allows the discharge of its contents, pull tab which comprises a generally flat member having an axially extending rod member with a proximal end portion adapted to be held and pulled by a user, and a distal end portion having leg members extending transversely to each side thereof, the rod and leg members are substantially coplanar to each other, the pull tab is fixed by the leg members externally to a wall of the container at or adjacent to the flange seal of the container, the container is characterized in that: a. The leg members are fixed substantially asymmetrically about the longitudinal axis of the rod member to a wall of the container and / or to the wall portion incorporated in the lip seal; and b. The pull tab has a point of rotation about which the rod member is bent with respect to the leg members when tension is applied to the proximal end of the rod member during the opening of the container, which point of rotation is located longitudinally with respect to the rod member substantially in alignment with the union of the rod member and the proximal edges of the leg members; and c. The fixing of each of the leg members to the container wall is by means of a fixing system which has an edge proximal to the point of rotation, which edge is configured so that at least a portion thereof is Extending perpendicular to a line extending from the proximal edge to a point of rotation, the line that intersects the edge is intermediate to the ends of it.

2. The package as described in claim 1, characterized in that the fixing of the leg members is by means of a thermal seal.

3. The package as described in claim 2, characterized in that the thermal seal is in the form of an in-line seal.

4. A container with box-shaped end having a pull tab externally fixed to a container wall at or adjacent to the container flange structure whereby separation force can be applied to the flange seal of the sealed container, the container is characterized in that the distal end of the pull tab is externally fixed to an outer wall of the container and wherein the attachment of the distal end is by means of at least two lines of fixation, one on each side of the longitudinal axis of the rod of the pull tab, each of the fastening lines which have at least a portion thereof which are configured so as to extend perpendicular to a line extending from the point of rotation of the rod to the pull tab and that intercepts the intermediate fixation line at the ends thereof.

5. The package as described in any of claims 1 to 4, characterized in that the distal end of the pull tab is fixed to a container wall by means of a fixing area or areas, at least one is on each side of the longitudinal axis of the tongue of the pulling tongue, the fixing areas extend longitudinally on each side of the rotation point of the tongue of the tongue for pulling.

6. The package as described in claim 5, characterized in that the fixing areas extend a distance d above (distally exceeding) the point of rotation and a distance d1 below (proximally short of) the point of rotation and the ratio of d: d 'has a value of 10: 1 to 1:10.

7. A container with a box-shaped end having one end closed by a transverse flange seal and having a pull tab so that a separation force can be applied to the flange seal of the sealed container so as to separate at least part of the container. of the flange seal and therefore open the container and allow discharge of its contents, pull tab which comprises a generally flat member having an axially extending rod member with a proximal end portion adapted to be clamped and pulled by a user, and a distal end portion having leg members that extend transversely to each side thereof, the rod and leg members are substantially coplanar to each other, the pull tab is fixed by the leg members. Legs externally to the container wall at or adjacent to the flange seal of the container, the package is characterized in that: a. The leg members are fixed substantially symmetrically about the longitudinal axis of the rod member to a wall of the container and / or to that portion of a wall incorporated within the lip seal, - and b. The pull tab has a point of rotation around which the rod member is bent with respect to the leg members when tension is applied to the proximal end of the rod member during the opening of the container, which point of rotation is located longitudinally with respect to the rod member substantially in alignment with the union of the rod member and the proximal edges of the leg members; and c. The fixing of each of the leg members to the wall of the container is by means of a fixing element having fixing areas which extend longitudinally a distance d above (surpassing distally) the point of rotation, and a distance d1 below (proximally short of) the point of rotation, and the ratio of d: d 'has a value of 10: 1 to 1:10.

8. The package as described in any of the preceding claims, characterized in that a portion of the intermediate rod member to the pasta members is not fixed to the container wall.

9. A container with a box-shaped end, having a pull tab externally fixed to a container wall at or adjacent to the flange structure, whereby a separation force can be applied to the flange seal of the sealed container, characterized because the distal end of the pull tab is fixed to an outer wall of the container and wherein the attachment of the distal end is by means of two portions laterally spaced from the distal end portion of the pull tab with an intermediate portion that does not is fixed, which is located between the fixed portions, whereby the pull tab exerts two opposing forces on the flange seal portion axially in alignment with the intermediate portion that is not fixed when the user pulls on the pull tab.

10. The container as described in any of the preceding claims, characterized in that the leg members are fixed to the gable-shaped end triangle walls of the gable-shaped end of the container.

11. A preform for use in the manufacture of a carton, as described in any of the preceding claims, characterized in that the preform comprises a series of connected panels adapted to be folded and fixed together so as to form the container, the portions terminals of two of the panels is adapted to form the gable end walls of the assembled container, defined in that a pull tab comprising a member is attached to or adjacent to the terminal portion of one or more of the wall panels. plane having a proximal end adapted to be held and pulled by a user, a rod member extending axially, and a distal end portion having leg members extending transversely to each side thereof, pull tab which is fixed to a panel of the preform by means of a fastener, wherein the fastener represents a proximal edge edge to the point of rotation of the rod member and configured so that at least a portion of the edge extends perpendicular to a line extending from the point of rotation to intercept the intermediate edge at the ends thereof .

12. A pull tab, for use in a package or preform, as described in any of the preceding claims, pull tab comprising a generally flat member having a proximal portion adapted to be held and pulled by a user, a member of longitudinally extending rod and a distal portion by means of which the tab can be fixed to pull a wall of the package or the preform, for use in the manufacture of a package, the tab is characterized in that the distal portion is provided with two leg members extending laterally on either side of the longitudinal axis of the rod member, each leg member extends proximally and distally longitudinally on both sides of the pivot point of the rod member.

13. The pull tab, as described in claim 12, characterized in that the included angle between the proximal edge of the leg member and the longitudinal axis of the rod member is 15 to 80 °.

14. A container, preform or pull tab, as described in any of the preceding claims, characterized in that the pull tab is made of a laminate of two polymeric materials, one having a melting temperature of at least 40 ° C higher than melting point of the other.

15. The container, preform or pull tab, as described in claim 14, characterized in that the pull tab is made of a polyester and polyethylene laminate.

16. A method for opening a container that can be opened, with a box-shaped end, as described in any of claims 1 to 10, which method comprises separating the seal between the dry walls at that end of the flange seal of the container. container adjacent to the pull tab, or to bend the ends of the flange seal so as to form a flange seal having a curved or T or Y configuration, and apply tension to the proximal end of the pull tab so that Separate the seal between the wet seal walls, preferably at the intersection of the vertical part and the upper part of the seal set to T or Y.

17. The method as described in claim 16, characterized in that the flange seal is initially separated at the intersection of the vertical part and the upper part of the seal configured in T or Y.

18. The method as described in claim 15, characterized in that the method comprises separating the seal between the dry walls at the end of the flange seal of the container adjacent to the pull tab, so as to form a flange seal having a configuration of Y reversed, and tension is applied to the proximal end of the pull tab so that it separates the seal between the wet walls of the upper part of the inverted Y.

19. The method as described in claim 15, characterized in that the arms of the upper part of the Y are inclined 120 to 180 ° each other.

20. The package as described in claim 1, substantially as described above with respect to, and as shown in any of the accompanying drawings.