Patent Application
20130284769
This application claims priority to German Application No. 20 2012 003 293.3, filed Mar. 30, 2012.
The present invention relates to a welded-in spout for connecting to a container, in particular for connecting to two foil walls of a plastic container.
By way of example, an object of the type in question is disclosed in DE 20 2006 013 587 U1. Comprehensive tests have shown that this object is not suitable for joining to the foil walls of a foil pouch or other container by means of ultrasound. This applies equally to spouts made of PE, for example, and to pouches or spouts made of polypropylene.
Typically, the welded-in spout (hereinafter also “spout”) has a base, also referred to as “boat”, the side walls of which have outer side surfaces which merge with one another at their end regions. The side surfaces are joined, in particular welded, to and between the two foil walls of the container. A collar-like region, which merges into a neck which has a pouring channel which has a vertical longitudinal central axis, is formed on the boat or side surfaces, typically in one piece. Such a neck is often provided with a thread on the outside in order to seal a filled foil pouch with a cap before emptying through the pouring channel. Alternatively, the neck can also merge, at least partially, directly into the boat. The side surfaces of the boat can be flat, rough or provided with or without ribs and/or with welding lines. In addition, the neck can have guide webs which can be used for guiding in a filling or sealing machine.
In order to stiffen the side walls of the boat, a welded-in spout of the type in question has a plurality of, i.e. at least two, stiffening webs on the inside which form corner transitions with the respective side wall, wherein, viewed in a plane perpendicular to the longitudinal central axis, a corner transition is defined by a contour of the welded-in spout located between two intersecting straight lines, wherein the one straight line constitutes the main extension of the surface of the side wall and the other straight line the main extension of the surface of the stiffening web (in each case viewed in the plane formed). In the plane viewed, when the stiffening webs run in a straight line, the straight lines are coincident with the edge of the web; the same applies in a similar manner for side walls which run in a straight line. If the side walls are curved, the straight line constitutes an asymptote to the edge side wall which touches the side wall where a straight line of the stiffening web starts to cut the side wall. If the stiffening web is curved where it meets a side wall, the straight line can also be replaced by an asymptote matched to the curvature of the stiffening web which then cuts the straight line of the side wall accordingly.
Comprehensive tests with welded-in spouts of the type in question which have web widths between 0.5 and 0.9 mm have shown that these cannot cope with the loads incurred during an ultrasonic welding process in which mechanical energy acts on the side walls as a result of the sealing jaws resting against the side surfaces of the boat. The stiffening webs break off. This must be avoided.
The objective of the present invention is therefore to design a welded-in spout of the type in question for use in an ultrasonic sealing station.
According to the invention, it is provided that the contour of at least one corner transition for stabilizing the welded-in spout during an ultrasonic welding-in process has a curvature of≦10/mm. In particular, the magnitude of the curvature which is less than or equal to 10/mm is considered. Surprisingly, in particular with the web widths between 0.5 and 0.9 mm used, it has been shown that the introduction of the energy transferred from the side walls into the webs has proved to be uncritical when the contour in the corner transition has a sufficiently shallow or small curvature. This phenomenon is not yet exactly understood, however it has been shown that no energy peaks occur at critical points as a result of not using thicker corners and therefore the introduction of energy from the side walls into the stiffening webs is “smoother”. The curvature or curvatures here are usually viewed from a point which, with respect to the straight lines of the side wall, is located on the side which lies on the inside of the welded-in spout. In particular, viewed from the (curvature center) point, the contour can be described by one or more adjacent circles of curvature or osculating circles.
Instead of stiffening for ultrasonic welding, such a boat can of course also advantageously be used for other vibration welding processes or welding processes based on similar principles. The boat can be used for welding processes with which energy pulses which lead to mechanical loads within the spout material are applied particularly repeatedly, e.g. in a pulsed manner, to the outside of the boat.
While a sufficiently smooth introduction of energy on only one side can be adequate without critical load peaks, it is advantageous to design corner transitions on both sides of the stiffening web in an appropriately rounded manner and provide them with a curvature, the magnitude of which is≦10/mm. In the following, when referring to values of the “curvature”, its magnitude is always considered.
The contour is always considered starting from a curvature center point which, as described above, is in each case arranged on the inside of the side walls between side wall and web in each case.
An embodiment of the invention is particularly advantageous when the contour of the corner transition forms a circular arc, which is easier to calculate when producing the mold for the welded-in spout.
An almost reject-free production of welded-in spouts which can be used for an ultrasonic welding process results when the contour of a circular arc section or the contour of the whole corner transition is in the form of a circular arc and has (a magnitude of) a curvature≦8/mm, preferably≦6.7/mm. The latter corresponds to a radius of an associated circular arc section of around 0.15 mm. Preferably, the radius of an associated circular arc section which constitutes the contour in the corner transition is at least 0.15 mm.
Advantageously, at least one stiffening web which reaches from the one side wall to the opposite side wall viewed in a bottom view in the direction of the longitudinal central axis is provided with a curvature≦10/mm, in particular≦6.7/mm in all four corner transitions. Preferably, such a stiffening web has a width between 0.7 and 0.55 mm.
A further improved introduction of the ultrasonic energy into the welded-in spout results when the stiffening webs of width between 0.55 and 0.7 have at least one corner transition with (a magnitude of) a curvature of≦3.5/mm.
Stiffening webs, which are provided with a width of 0.6 mm, for example, and are attached to only one side wall, also preferably have a curvature of≦10/mm, preferably≦6.7/mm.
It has been shown that, other than expected, the thicker stiffening webs with widths of 0.7 or 0.8 mm, for example, in particular must be provided with smaller curvatures, i.e. larger radii of curvature, in order to make a welded-in spout suitable for ultrasonic welding.
As well as the transitions to the side walls, the boat of a welded-in spout also has a collar-shaped section, also referred to as cover, in the transition region to the neck. The stiffening webs are also attached to this section where they form cover transitions. These are preferably provided with a curvature≦10/mm, preferably with a curvature≦6.7/mm.
In a similar way to the corner transitions, the cover transitions are defined as a contour of the spout between intersecting straight lines which run in the side surface of the stiffening web and in the cover. A plane in which the central longitudinal central axis lies is considered here. The cover transition is preferably designed in the form of a circular arc or in sections in the form of a circular arc.
The objective set in the introduction is likewise achieved by preferably small welded-in spouts (i.e. provided with a pouring channel diameter of less than 8 mm) which have no stiffening webs but with which the transition of cover and side wall is stiffened. The cover-side transition of these welded-in spouts is defined in a similar way to the transitions described above, namely based on straight lines which cut the respective surface in an osculating manner. According to the invention, such a cover-side transition is provided with a curvature which is less than 10/mm, wherein the curvature center point is in turn located in the material-free region between cover and side wall. The developments of the other transitions described above or below also apply to these welded-in spouts.
In particular, such a cover-side transition in one of the spouts described above or below which are provided with stiffening webs, can also lead to developments according to the invention. In a further advantageous exemplary embodiment of the invention, as well as the corner transition described above, a cover-side transition of the side wall to the cover is also provided with a curvature less than 10/mm. This also ensures that the side wall is attached to the cover in the best possible manner. Here too, the cover-side transition is defined in a similar way to the further corner or cover transitions.
Both the various cover and cover-side transitions and the corner transitions between stiffening web and side wall can preferably be provided with a radius r in such a way that, for the radius r of the circular-arc-shaped corner, cover or corner-side transition:
r=m*φ+b
where
φ=angle [°] between the respective parts of the welded-in spout (stiffening web, side wall and cover),
1.5*10−3 mm/°≦m≦7*10−3 mm/°,
−0.3 mm≦b≦0.2 mm.
This simple dependency has been crystallized from a multiplicity of comprehensive tests, wherein the optimum parameters are considered approximately as the actual effective correlation has not yet been clarified. The curvature center points of the cover transitions and the side-cover transitions are located between web and cover and between cover and side wall respectively.
These aspects are merely illustrative of the innumerable aspects associated with the present invention and should not be deemed as limiting in any manner. These and other aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the referenced drawings.
Reference is now made more particularly to the drawings, which illustrate the best presently known mode of carrying out the invention and wherein similar reference characters indicate the same parts throughout the views.
In the figures, in schematic form:
In the following detailed description numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. For example, the invention is not limited in scope to the particular type of industry application depicted in the figures. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.
Similar or similarly acting parts are—where appropriate—provided with identical reference numbers. Individual technical features of the exemplary embodiments described below together with the features of the exemplary embodiments described above can also lead to developments according to the invention.
According to
Corner transitions 7.1, 7.2, 8.1, 8.2, 9.1, 9.2, which are defined in more detail below, are formed between the side walls 12 and 11 respectively and the stiffening webs 7, 8, 9 (cf.
The following straight lines 7.3, 7.4, 8.3, 8.4 and 9.3, 9.4 are associated with each stiffening web 7, 8 and 9, in each case with the main extension of the stiffening web, in its respective side surfaces in the defined plane perpendicular to the vertical longitudinal central axis 1. In addition, a straight line 10.1 runs along and coincident with the main extension of the surface 10 of the side wall 11.
The straight lines 7.3, 7.4, 8.3, 8.4 and 9.3 and 9.4 cut the straight line 10.1 in the surface 10.10. As can be seen, the contour of the spout runs offset from these straight lines, as a result of which the corner transitions 7.1, 7.2, 8.1, 8.2, 9.1, 9.2 are formed by this contour of the welded-in spout. The contours in each case correspond to circular arc sections of an imaginary circle, the radius of curvature of which, in the case of corner transitions 7.1, 8.1 and 9.2, is 0.15 mm (radius of curvature). Correspondingly, the corner transitions have a curvature of around 6.7/mm.
The corner transitions 7.2, 8.2 and 9.2 have a curvature of around 3.3/mm and therefore a radius of curvature of 0.3 mm.
As a result of this embodiment of a welded-in spout according to the invention, it is suitable for an ultrasonic welding-in process.
Preferably the radii belonging to the individual circular arc sections have a length of at least 20%, preferably of at least 25% of the associated width 8 of a stiffening web.
In a similar manner to the corner transitions defined and explained in
13 and viewed in a plane 15 can be defined. In this case, the plane 15 includes the central longitudinal central axis, but can also lie parallel thereto. The cover 13 is part of the collar 5. The cover transitions provided here (for example 8.5 and 8.6,
Guide webs 14 are used for feeding to a sealing station or to a filling station for example.
Two further transitions 8.7 and 8.8, which are provided between the side wall 11 and 12 respectively and the cover and are defined in a similar way, are shown in the exemplary embodiment according to
A further welded-in spout according to the invention is shown in a bottom view in the exemplary embodiment of
The preferred embodiments of the invention have been described above to explain the principles of the invention and its practical application to thereby enable others skilled in the art to utilize the invention in the best mode known to the inventors. However, as various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by the above-described exemplary embodiment, but should be defined only in accordance with the following claims appended hereto and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202012003293.3 | Mar 2012 | DE | national |
