CA1124477A

CA1124477A - Method and arrangement for fastening a stabilizing arrangement on a container

Info

Publication number: CA1124477A
Application number: CA301,017A
Authority: CA
Inventors: Kjell M. Jakobsen
Original assignee: PLM AB
Current assignee: Rexam AB
Priority date: 1977-05-02
Filing date: 1978-04-12
Publication date: 1982-06-01
Also published as: IT7867984A0; FR2389474B1; ES469839A1; IT1107198B; JPS6139896B2; AU523592B2; SE406291B; GB1597802A; JPS53136075A; AT380828B; DE2817059C2; DK190678A; FR2389474A1; SE7705037L; BE866600A; CH628586A5; ZA781911B; AU3556378A; BR7802648A; DE2817059A1

Abstract

ABSTRACT OF THE DISCLOSURE

A method of welding a stabilizing arrangement of plastics material onto a container of plastics material com-prising the following steps: applying a force against the middle portion of the bottom of the stabilizing arrangement in order to cause it to lie against a middle portion of the bottom of the container; transmitting energy by means of an element towards a region in which the middle portion of the bottom of the stabilizing arrangement lies against the middle portion of the bottom of the container, thereby welding the stabilizing arrangement to the container in the middle portions of the arrangement and container respectively.

Description

~ 7 7 The present invention relates to a method and an arrangement for fastening a stabilizing arrangement on a con-tainer particularly for fastening a foot onto a bottle. The invention is suitable for application where both the stabilizing arrangement and the container consist of plastics material.
There is great interest in the ability to make con-tainers of plastics material for storing beverages. This inter-est is due, in part, to the desire to reduce the weight of the packing used to as great an extent as possible, while simul-taneously utilizing the good properties of plastics material,particularly ;ts impact strength. The types of plastics material used for this purpose are, however, relatively expensiye. Accordingly, it is also necessary for economic reasons to employ the smallest possible wall thickness of the containers used, thereby saving on materials.
In order to withstand the loads to which the material packed in the containers is exposed, the parts of the containers which are subjected to these stresses, for example, the bottom of a bottle, must be so constructed as to make the most effec-tive possible use of the strength of the material. This isparticularly important when containers of plastics material are used to store materials under pressure, for example, beverages containing carbon dioxide. Because of the requirements explain-ed above, this means that the bottom of a container should have a mainly circular shape.
For a container such as a bottle for storing materials, it is essential that it should be possible to store the container in an upright position. With a container having a bottom of semi-spherical shape, this is impossible. As a result, such containers are equipped with supporting arrangements, such as feet. Various types of feet have been used, including parts projecting from the bottom of the bottle or separate parts fixed ~3.,~

to the containers, In the last-mentioned case, these parts are applied to the container by snap engagement, riveting, or comparable methods.
According to the present invention, a method and an arrangement are provided for fastening a separate member, which consists of a supporting arrangement, to a container of plastics material. According to the invention, the supporting arrangement is welded to the container. The invention can be applied to combinations of plastics material when the plastics material in the supporting arrangement and container are weld-able. Examples of such plastics materials are polyethylene, polyethylene terephthalate, acrylonitrile, and polyvinyl chloride.
According to the present invention, the stabilizing arrangement is guided into a position in which it lies against the container. The material of the stabilizing arrangement is thus pressed against the material of the container.
According to one embodiment of the invention, the inclination of the bottom of the container to become deformed during the fastening of the arrangement is compensated for by subjecting the internal volume of the container to pressure.
This embodiment is often suitable for use with thin-walled containers. As an alternative, the application of pressure is replaced by a mechanical holding means. A mandrel for trans-mitting energy, for example, ultrasound, is brought into a position in which the mandrel transmits energy to the materials of the stabilizing arrangement and the container in a region which corresponds substantially to that where the stabilizing arrangement lies against the container. The stabilizing arrange-ment is thus welded to the container. When this has been done, the welded container and stabilizing arrangement are cooled.
After the stabilizing arrangement and the container have been welded together, a bending moment is produced in the ~.2~47~7 stabilizing arrangement and results from displacing the mid-dle bottom portion of the stabilizing arrangement in relation to the other parts of the latter before the welding is carried out. This displacement is achieved by moving the middle bottom portion in the direction of the bottom of the container so that after application to the container, an upper edge of the stabilizing arrangement disposed in this form presses against the container.
An arrangement according to the invention for fast-ening stabilizing arrangements on containers consists of a supporting member which continuously receives the stabilizing arrangements in unison at a rate at which the stabilizing arrangements are to be welded to the containers. A gripping means acts on the containers in such a manner that each in-dividual container lies against the stabilizing arrangement under the action of compressive forces when the stabilizing arrangement lies in the supporting means. A means of giving up energy, for example, an ultrasonic welding means, is brought by driving means into contact with the material of the stabilizing arrangement and transmits energy to the region of contact between the material of the stabilizing arrangement and the container. The materials are thereby heated and the stabilizing arrangement is welded to the container. If necessary, the container is given a stable shape during welding utilizing a holding-up means which assumes a position against the inner surface of the container in the welding region. Alternatively a pressure application element can be employed to hold the internal volume of the container under increased pressure.

Two concentrically disposed rings are provided in the supporting element for the stabilizing arrangement. The outer ring preferably has a beaker-like appearance and is adapted to the outside dimensions of the stabilizing arrangement. In certain embodiments, the ring is disposed on a number of relative-~ .2 ~477 ly soft springs.
The inner ring has an inside diameter which is adapted to the outside diameter of a mandrel which transmits energy.
In this arrangement, it is possible for the mandrel to slide through the ring in order to bear against a stabilizing arrange-ment when the latter rests against the inner ring.
When a stabilizing arrangement has been introduced into the supporting means, a middle portion of the bottom thereof rests against the upper surface of the inner ring and is, at the same time, centered in the supporting means by the outer ring. In the embodiment where the outer ring is suspended on springs, it is situated in an upper position under the action of the springs.
A gripping means acts in sequence on the containers by bringing them into a position with bottom parts thereof, dis-posed in the stabilizing arrangement. The latter more or less embraces the bottom part of the container. The gripping means then acts on the container in such a manner that it is moved in the direction of the stabilizing arrangement. The middle portion of the bottom of the stabilizing arrangement is fixed in position in the supporting element with respect to the inner ring, whereas the outer parts of the stabilizing arrangement are displaced relative to the middle portion of the bottom through the action of the container. If necessary, this is per-mitted by the previously mentioned spring suspension of the outer ring. Through this displacement of the container, reliable contact is also obtained between the middle portion of the bottom of the container and the middle portion of the stabiliz-ing arrangement.
In one embodiment of the invention, an arrangement simultaneously embraces the mouth p~tion of the container in such a manner that the latter forms a closed space. Pressure is applied to the interior of the container, whereby it is stabilized against mechanical displacement. The element used for embracing the mouth portion of the container preferably consists of the previously-mentioned gripping element.
The above-noted assistance in the displacement of the container for a relative movement of the material of the stabilizing arrangement is preferably provided by the gripping element. In one embodiment, the gripping element is displaced with a roller lying against a cam so that when a relative displacement occurs between the roller and the cam, the gripping element is displaced in the direction of the stabilizing arrange-ment.
With the stabilizing arrangement and the container fixed in relation to one another in the manner described above,, a mandrel is thereupon guided through the inner ring, into con-tact with the material in the middle portion of the bottom of the stabilizing arrangement so as to transmit ultrasonic energy thereto. Ultrasonic energy is given up to the material of the stabilizing arrangement and container, and the stabilizing ` 20 arrangement is thus welded in this region to the bottom of the container. With the stabilizing arrangement and the container also fixed in relation to one another by external elements, the welded part is then cooled, the internal excess pressure (where applied) is relaxed or the holding-up means used is removed, whereupon the external fastening element is taken away, and the container, together with the stabilizing arrangement welded to it, is carried away from the production unit.
The inner ring is preferably mounted for sliding in the supporting element, so that the distance of the container in the axial direction between the upper surface of the inner ring and the upper surface of the outer ring is adjustable.

The relative displacement between the middle portion ~.2~9~77 of the bottom of the stabilizing arrangement in relation to the remainder of the latter is effected in an alternative embodiment of the invention through the displacement of the inner ring, optionally in conjunction with the displacement of the outer ring.
The positioning of the individual stabilizing arrange-ment in the supporting element and also the displacement of the containers with or without the stabilizing arrangements can be effected in accordance with a known technique. For example, a suction means may be used to secure the stabilizing arrange-ment, and a vacuum tube may be employed for bringing the com-pleted containers to a storage site.
In one aspect of the present invention there is provided a method of securing a stabilizing arrangement of plastics material onto a container of plastics material, said stabilizing arrangement having a bottom middle portion and a peripherally extending rim portion and said container also having a bottom middle portion, said method comprising the steps of: a) placing said container within said stabilizing arrangement such that there is contact therebetween at their respective bottom middle portions and while in such position slidable engagement may occur between said rim portion and - said container and b) securing said container to said stab-lizing arrangement at said respective bottom middle portions only thereby permitting said slidable engagement between said rim portion and said container to remain possible.
In a further aspect of the present invention there is provided an arrangement for securing a stabilizing arrange-ment of plastics material onto a container of plastics material, the arrangement comprising: a supporting element for receiving and carrying a stabilizing arrangement to be secured to the bottom of a container; a gripping element to ~L~ Z~477 cause a container to lie with a bottom surface thereof against a stabilizing arrangement in the supporting element an element for transmitting energy operatively connected to drive means, the drive means adapted to bring the element into contact with the material of the stabilizing arrangement adjoining a region where the material of the stabilizing arrangement lies against the material of the container, the element for transmitting energy adapted to transmit energy to the material of the stabilizing arrangement, and to the material in the container in the aforesaid region thereby securing the stabilizing arrangement to the container.
In drawings which illustrate a preferred embodi-ment of the present invention:-FIGURE 1 is a perspective view of an arrangement operating in accordance with the present invention, and FIGURE 2 is a partial vertical section illustrat-ing how the element for welding the stabilizing arrangement to the container is mounted.
In Figure 1, a plate 100 is mounted on a shaft driven by a mechanism 101. The plate is rotatable stepwise so as to assume fixed stopping positions. A number of supporting elements 20 are disposed on the plate. The supporting elements 20 conform to the dimensions of the stabilizing arrangements 30 which are to be joined to the container 10. Control elements 21 corresponding to the dimensions of the containers are connected to the support-ing elements. An element 50 for transmitting energy, for example, for ultrasonic welding, is situated at one of the positions for the supporting elements 20, The element 50 is equipped with a mandrel 51 which can be displaced from a lowered position lying under the plate -6a-~ Z~ 7 100 to an upper position -6b-in which the mandrel is situated in the supporting element 20.
A cooling element 53 is located at a downstream position relative to the element 50. The cooling element 53 is provided with a mandrel 52 which can be moved from a position beneath the plate 100 and an operative position situated within the supporting element 20.
A gripping element 40 associated with each individual supporting element 20 is arranged to assume a position in which it secures the individual containers 10 to the supporting elements 20. In one embodiment of the invention, the gripping elements are connected to a pressure application means 81, which consists of a container for compressed air and is equipped with valves for connecting and disconnecting the gripping element to and from the pressure application means. The gripping ele-ments are arranged to make sealing connection with the mouth portions of the containers, so that when the valve connected to the pressure application means is opened, an excess pressure is produced in the containers.
A supporting disc 80 is arranged to cooperate with the gripping elements 40. In one embodiment, the gripping elements are provided with a roller 41 lying against the support-ing plate 80. The direction and shape of the supporting plate are so selected that when it performs a relative movement with respect to the supporting disc 80, the gripping element 40 is moved in the direction of the supporting elements 20.
The stabilizing arrangement is fed with the aid of a magazine 60 containing individual stabilizing arrangements, a feed means 61, such as a worm, and a suction element 62. The suction element 62 secures a stabilizing arrangement fed by the feed means, and brings it into the desired position in the supporting elements 20. The suction element 62 is movable between a position under the plate 100 and a position above the supporting means 20. The suction element is common to all the supporting elements 20. Finished containers with stabilizing arrangements welded to them can be discharged with the aid of a suction discharge pipe 70, as shown in the drawing.
Figure 2 shows in detail how the supporting elements 20 are mounted in one emboaiment of the invention. The plate 100 and a mandrel can be seen in the drawing, the mandrel being either a mandrel 51 for transmitting energy, for example, for ultrasonic welding, or a mandrel 53 for cooling. In addition, the bottom part of the container 10 is shown, as well as the stabilizing arrangement 30. In addition to these parts, Figure 2 also shows an outer ring 22, preferably of metal, and an inner ring 23. The outer ring is mounted on a number of springs 24 so that the ring can be moved between a raised initial position some distance above the plate 100 and a lowered position close to the plate. The inner diameter of the outer ring 20 conforms to the outside diameter of the stabilizing arrangement 30, so that the outer ring lies against the stabil-izing arrangements.
The inner ring 23 is joined to the plate 100, and is usually displaceable with respect to the plate 100, for example, by being screwed into the plate by means of a screw-thread. The inside diameter of the ring enables the mandrel 51 or 53 to pass through it. It can also be seen that the plate 100 also permits the passage of the mandrel. The upper surface of the inner ring lies approximately flush with the bottom surface of the outer ring 22.
In Figure 2, it can be seen how the middle portion of the bottom of the container 10 is situated some distance from the middle portion of the bottom of the stabilizing arrangement 30. This is the starting position for the container when the latter has first been brought into a position for welding to 7~

the stabilizing arrangement. In the following stage of the pro-cess, the container is subjected to forces which are directed towards the stabilizing arrangement, so that the container to-gether with the outer parts of the stabilizing arrangement is displaced towards the plate lO0. The middle portion of the bottom of the container lO thus reaches a position in which the material of that portion is pressed against the material in the ' middle portion of the bottom of the stabilizing arrangement.
Since it is suspended on springs 24, the outer ring 22 can follow the stabilizing arrangement during this movement. The welding and cooling of the welded region are effected with the container - and stabilizing arrangement lying in the position close to the plate lO0.
The mode of operation of an arrangement according to the description given above is explained below. With the aid of the feed means 61, the stabilizing arrangements are fed individually from the magazine 60 to the supporting elements 20. This takes place with the supporting elements 20 in the position designated position 1. The final positioning of the stabilizing arrangement in the supporting element is effected by the suction element 62, which takes over the stabilizing arrangement 30 after the latter has been delivered by the feed means 61. The control element 21 assists the suction element in the correct directing of the stabilizing arrangement.
The plate 100 is thereupon turned one step in its direction of rotation and a container 10 is placed on the supporting element 20' by means not shown in the drawing, thus also being placed on the stabilizing container in the supporting element. The control element 21' ensures the correct orientation of the container. The gripper 40' is brought into the position for closing the mouth portion of the container 10'.

The plate lO0 is rotated one step further. If necessary, 7~

pressure is then applied to the interior of the container. The roller 41l' of the gripping element 40" is operated during the movement of the supporting plate 80 in such a manner that the container 10" is moved in the direction of the supporting element 20l'. The stabilizing arrangement 30" is thus acted on by the container 10" in such a manner that the stabilizing arrangement and the container assume correct positions relative to one another for the subsequent welding.
The plate 100 is now rotated one step further. The mandrel 51 on the element 50 for the supply of energy, for example, for ultrasonic welding, is moved upwardly towards the middle portion of the bottom of the stabilizing arrangement 30"'.
Ultrasound energy is transmitted by the mandrel and the material in the middle portion of the bottom of the stabilizing arrange-ment, and also the corresponding parts in the bottom of the container, are heated and the container is thereby welded to the stabilizing arrangement. The mandrel 51 then returns to its position below the plate 100.
The plate 100 is now advanced a further step. The mandrel 53 of the cooling means 52 then assumes a position in which it lies against the middle portion of the bottom of the stabilizing arrangement 30 and thus cools the material in this region and also in the region of the middle portion of the bottom of the container. This cooling lasts until the necessary strength has been achieved in the bond between the stabilizing arrangement and the container.
The plate 100 is advanced one more step, the roller 41 on the gripping element 40 thus being freed from engagement with the supporting plate 80. The application of pressure to the interior of the container, in cases where pressure is applied, then ceases. The gripping element can thus return to its starting position. The container, together with the stabilizing arrangement welded to it, is released for removal from the production unit. This can be achieved by means of an ejection device or utilizing a suction pipe 70.
' With the construction described, a number of positions may be provided for the supporting element 20 between the position for cooling the welded region and the position for removal from the production unit. These positions may, for example, be utilised for inspecting the products and also for ejecting any which do not pass this inspection.
The arrangement described also makes it possible for a central control system for the sequence of production operation to be provided, for example with the aid of a micro-; dator. The latker attends to all the control functions and ;~ pulses necessary for enabling the operating elements to make the movements necessary for the sequence of operations.
'~ In some applications, the outer ring 22 may have a fixed orientation in relation to the plate 100. This arrange-ment is expedient when the additional security provided through the movable suspension of the outer ring 22 in respect of the orientation of the bottom of the container in relation to the stabilizing arrangement is not necessary.
The foregoing text describes an arrangement working in accordance with the principle of the invention and consist-ing of a number of working stations which are positioned on a plate 100, which performs a circular movement during the course of the operation. It is obvious that the invention is not restricted to the use of an apparatus arranged in this manner, but may also be applied with a more or less linear movement of production elements. In accordance with the principle of the invention, it is equally possible for the separate production stations to be fixed in position and for the containers and supporting elements to be moved between the various production

2~x ,~7 stations. A combination of the two alternative arrangements may be found economical in certain cases.
An advantage of the invention which has not so far been mentioned consists in that when fastened to the container, the stabilizing arrangement is assured of accurate orientation in relation to the vertical axis of the container. Problems in connection with the filling of the container are thus over-come. Previously known foot constructions in which the foot clips on the container do not provide the accurate orientation achieved here.
In addition to the above description, the invention is characterized by the following patent claims.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of securing a stabilizing arrangement of plastics material onto a container of plastics material, said stabilizing arrangement having a bottom middle portion and a peripherally extending rim portion and said container also having a bottom middle portion, said method comprising the steps of:
a) placing said container within said stabilizing arrangement such that there is contact therebetween at their respective bottom middle portions and while in such position slidable engagement may occur between said rim portion and said container; and b) securing said container to said stabilizing arrangement at said respective bottom middle portions only thereby permitting said slidable engagement between said rim portion and said container to remain possible.

2. A method according to claim 1, wherein during the securing to the container, a bending moment is produced in the stabilizing arrangement due to the application of force against the middle portion of the bottom of the stabilizing arrangement which displaces that portion relative to the other parts of the stabilizing arrangement so as to cause it to lie against the middle portion of the bottom of the container, the middle portion of the bottom of the stabilizing arrangement remaining substantially in this position in which it is dis-placed relative to the other parts of the arrangement after securing.

3. A method according to claims 1 or 2, including the step of placing the interior of the container under pressure during the securing operation in order to increase the mechanical stability of the container.

4. A method according to claims 1 or 2, including the step of applying a mechanical holding-up means against the inner surface of the container adjoining the region where the middle portion of the bottom of the stabilizing arrangement lies against the container during the securing operation in order to increase the mechanical stability of the container.

5. A method as defined in claim 1 wherein said securing comprises welding.

6. An arrangement for securing a stabilizing arrange-ment of plastics material onto a container of plastics material, the arrangement comprising: a supporting element for receiving and carrying a stabilizing arrangement to be secured to the bottom of a container; a gripping element to cause a container to lie with a bottom surface thereof against the stabilizing arrangement in the supporting element; an element for transmitting energy operatively connected to drive means, the drive means adapted to bring the element into contact with the material of the stabilizing arrangement adjoining a region where the material of the stabilizing arrangement lies against the material of the container, the element for transmitting energy adapted to transmit energy to the material of the stabilizing arrangement, and to the material in the container in the aforesaid region thereby securing the stabilizing arrangement to the container.

7. An arrangement according to claim 6, wherein the element is an ultrasonic welding element.

8. An arrangement according to claim 6, wherein the gripping element causes the container to lie with a bottom surface thereof against the stabilizing arrangement through the action of compressive forces between the bottom and the stab-lizing arrangement.

9. An arrangement according to claim 6, including an element for cooling the heated material after the securing of the bottom of the container and the stabilizing arrangement is pro-vided.

10. An arrangement according to claim 9, including a pressure element for placing an interior of the container under pressure, whereby the container is mechanically stabilized during the welding and cooling processes.

11. An-arrangement according to claim 9, wherein a mechani-cal holding-up means is provided for lying against an inner sur-face of the container, in the region where the container is heated, during the securing and cooling processes.

12. An arrangement according to claim 6, wherein the supporting element is provided with an outer beaker-shaped ring matching the outside dimensions of the stabilizing arrangement and with an inner tubular part which is arranged with one end portion thereof lying against the middle portion of the bottom of the stabilizing arrangement, the tubular part being so shaped as to permit passage of the element transmitting energy, thereby enabling the element to bear against the middle portion of the bottom of the stabilizing arrangement.

13. An arrangement according to claim 12, wherein the beaker-shaped ring is connected by means of springs to a plate which carries the supporting element, the inner tubular part being adjustably fixed in the plate, whereby when forces are applied to an edge of the stabilizing arrangement in a direction of the plate, outer portions of the stabilizing arrangement can be displaced in relation to the middle portion of the bottom of the stabilizing arrangement lying against the tubular part.

14. An arrangement according to claims 6, 8 or 9, including a magazine for stabilizing arrangements, whereby the stabilizing arrangements are fed individually by a feed means to the support-ing element.

15. An arrangement according to claims 6, 8 or 9, wherein the container is aligned by a control element in relation to a supporting element in order to cause the container to lie against a supporting arrangement positioned in the supporting element.

16. An arrangement according to claims 6, 8 and 9, wherein upon completion of the securing of the stabilizing arrangement to the container, a suction tube moves the container, together with the stabilizing arrangement secured to it, from the supporting element.

17. An arrangement according to claims 6, 8 and 9, wherein the container can be moved between a number of positions, the container remaining stationary for the period of time in each position.

18. An arrangement according to claims 6, 8 or 9, wherein the container is moved substantially continuously for the pur-pose of joining the container to the stabilizing arrangement.