IL42821A

IL42821A - Method and device for making a closure capsule for containers

Info

Publication number: IL42821A
Application number: IL42821A
Authority: IL
Original assignee: Remy Ets Pierre
Priority date: 1972-07-28
Filing date: 1973-07-25
Publication date: 1977-10-31
Also published as: IE39004B1; IE39004L; DE2337661A1; AU5865573A; ES216707Y; ES216707U; ES417336A1; GB1420470A; IT1005236B; IL42821A0

Description

Method and device for making a closure capsule for containers ETABLIS3 TS PIERRE REMY 0. 41005 42821/2 or other similar containers , to a method of making such a closure capsule and to a device on which the method is carried out.

For a long time it has been proposed to make such capsules or closure members of thin metal or of a cellulose material which, placed moist on the container, tightly grips the container by shrinking caused in drying. Alternatively it has been proposed that a shrinkable thermoplastic material be used hich after being put into position on the container without heat, is subjected to the action of heat and shrinks tightly, taking the exact shape of the container. For the last mentioned case, it has been proposed to start with a suitable length of tube of thermoplastic material such as polyethylene or polyvinyl chloride to form a tubular blank by placing this length on a frustoconical forming member or mandrel on which the tube is heated, then cooled, and placed on a closed bottle where it is again heated so that it takes exact shape of the container* Such a method is described in French Patent No. 1,424,723 and elsewhere.

Nevertheless, this known method has the drawback of requiring the prior manufacture of tubes in a special set-up; moreover, it requires special precautions and a relatively long time for printing the indicia or decorative markings required on the capsule. In addition, for obtaining a bottle closure member, the disc forming the closed end of the capsule must, in this method, have a diameter equal to that of the smaller base of the truncated cone so as to be able to be 42821/2 positioned between bent-over portions thereof and the forming member, leaving only a small amount of space for tax markings and other indicia which are to be printed on the capsule.

The disc may be of plastics material or metal foil, for example, of aluminium.

The development of technology capping and the government requirements, namely, on the end disc showing an excise tax, have led the applicant to seek to avoid the above-mentioned drawbacs in order to obtain as economically as possible capsules fully answering to the government and commercial requirements.

It has also been proposed to this end to replace the aforesaid tube by strips pre-cut from a sheet or strip of polyvinyl chloride shrinkable in the direction perpendicular to the direction of forward displacement, i.e. in the conditions corresponding exact, to those encountered when starting with a tube of shrinkable polyvinyl chloride or a sheet of aluminium. This so.lution in cutting strips has in fact produced certain advantages, but it was soon determined that it in no way eliminated, among others, the above-mentioned coloration and printing difficulties.

Thus, in French Printed Patent Application No. 2,115,137, a method of making closure capsules was described in which a strip of mono-oriented thermoshrinkable material is provided and blanks are cut out from the strip taking the direction of drawing or stretching the strip as the direction of the circumferential edges of the capsule panel or blank.

By application of heat such a capsule shrinks radially i.e., perpendicular to the axis of the bottle on which it is positioned without shrinking parallel to this axis. ^ In order that such closure capsule ray be made in conventional set-ups, as described hereinabove, the strip must be drawn or stretched perpendicular to its length. In this manner the blanks cut out perpendicular to the length of the strip have the desired orientation.

Means for providing a strip stretched perpendicular to its length are v/ell known to one having ordinary skill in the art, and comprise two flat clips each grabbing one of the edges of the strip over a given length, e.g., one meter, and then subjecting it to a pulling force by moving the clips away from each other.

Such means have the following drawback: owing to stretching it is found that the thickness of the strip varies irregularly , the center being more often thinner than the marginal areas. One might think that such differences in thickness result from the internal nature of the strip before stretching.

In'fact, to provide a strip of plastic material, plastic material in a vessel is generally extruded continuously through an elongated die thereby obtaining a thick strip which is later rolled to reduce its thickness as desired. The central portion of the strip comes from the middle of the vessel through the central portion of the die. One having ordinary skill in the art knows that the central area is less longitudinally oriented than the marginal areas which come from the zones closer to the walls of the vessel and which are subjected to greater stresses Since they pass closer to the edges of the die.

It follows that the quality of such transversely stretched strips is rarely perfect and one even finds holes caused by stressed concentrations provoked by stretching around the irregularities of the central portion undergoing greater deformation. The presence of holes is the reason for discarding material and cause of waste .

Another shortcoming of this method is that, for example, during the drying of the printed indicia, overheating may cause a • contraction of the material; it is not possible to prevent such contraction, because known machines do not enable the strip to be held" under tension up to this point without very substantially modifying the rmchine.

For' the above reasonsj it would appear advantageous to be able to use strips stretched lengthwise, yet such a method has not been described in the prior art literature.

Several possible explanations may be given for this fact: First of all, the strips of thermoshrinkable material stretched lengthwise have not been commercially available. There are several theoretical methsds-for preparing such strips but none is in industrial use, so that potentional users of such strips would have had to manufacture the same themselves, with the incumbent risks, particularly that of obtaining a product which might not be better than pre-existing products.

Secondly, if a lengthwise stretched strip is used in a conventional machine, the resulting capsules tend to shrink parallel, and not perpendicular, to the axis of the bottles on which they are received so that the machine would have to be modified to attain the sought after result.

Lastly, if blanks with part-circular edges are cut out, a wasted scrap results between the straight edge of the strip and the concave edge of the blank.

It is readily understood that for these various reasons no industrial method making use of strips stretched lengthwise has been disclosed in any prior art literature.

The main object of the present invention is to provide a method 1 of making closure capsules of thermoshrinkable plastic material adapted to shrink upon the application of heat towards the axis of the bottle on v/hich it is received and perpendicular to said axis without shrinking parallel to the axis, and having a reduced percentage of rejects and reduced amounts of scraps, and a lower production cost .

Another object of ths present invention consists in a method of making closure capsules as described hereinabove, by^ using a set-up for forming such closures which differs from those, in use, only by minor, inexpensive modifications.

Another object of the present invention is the provision of a method which enables momentary overheating of the material, especially during drying following printing, to be eliminated .

The .applicant then get the idea to manipulate and process the starting strips in the direction of their mono-orientation by taking as the direction of forward displacement or progress in the manufacture of the capsules, the direction of th¾ mono-orientation, i . e . shrinking in the direction of forward movement or progress One aspect, of the invention consists in a method of - 3 - making such a capsule, wherein strips of polyvinyl chloride or other nono-orientated thermo-shrinkable synthetic material are displaced in the direction of their mono-orienta ion, the strips being marked, cut, rolled into truncated cones, closed at their small base by bxi exterior disc on an annular bent-over portion and stored, on any suitable type of machine. It has been found that this method avoids the "transverse" rolling of the strip about itself, that is folding back about the longitudinal axis.

Another aspect of the invention concerns the closure capsule of thermoshrinkable mono-orientated . synthetic material obtained according to the above-defined method, comprising a continuous skirt of which the axis of revolution is perpendicular to the direction of mono-orientation and disc fixed to the outside of the horizontal annular bent-over portion at one end of the skirt.

It should be noted that under the conditions of the invention the pulling in the direction of forward displacement directly compensates for the shrinking to which the strip is subjected ; firstly, it is possible to dry the markings and evaporate the solvents at a higher temperature, and consequently increase the printing rate as well as the overall output of the machines. Preferably, the strips of mono-orientated PVC (polyvinyl chloride) displaced in the direction of the mono-orientation are provided with the desired markings in a trapezoidal shape appropriate for their subsequent rolling into truncated cones, cutting out and then forming the capsules in a known manner. It is also obvious that it is possible to do without the outlines, the cutting device always cutting out the desired shape. j| · The trapezium shaped cutting out from which each capsule is developed produces scraps, but surprisingly it has been found that the invention enables a less expensive and simpler manufacture in spite of the scraps than the manufacturing methods using a strip shrinking perpendicular to the direction df displacement. Further, it has been found that by employing according to the invention a strip shrinkage in the direction of forward progress, the coefficient of shrinkage may reach 80$ whereas,, in the case of a transverse shrinkage (perpendicular to the direction of forward progress) it is difficult to exceed in practice 0 shrinkage .

The method according to the invention may be carried out on conventional stamping or printing machines in which the evaporation temperatures of the printing solvents are set at higher values., therefore the printing rate may be more rapid without the slipping or deformation of the markings on the strip since the pulling force exerted by the forward progress is enough to compensate for the slight lateral shrinkage and resultant deformations of the markings.

Preferably, the base of the forming cone or the small base of the frustoconical mandrel supporting rough shapes of capsules during formation is provided with a slight annular peripheral notch : the portion of the rough shape which extends above the support is thus guided during its heating so as to form a horizontal flange along the small base of the support.

For the source of heat, a gas flame, a hot air generator, an infrared ray source or the like may be used ; the heat emitted is directed towards the end of the truncated cone of shrinkable material projecting beyond the forming cone at an angle which is generally in the,vicinity of 5° as a function of the diameter and length of the capsule.

For securing the sides of the frustoconical rough shape, it is possible to apply a strip of ^ glue, for example, thermoadhesive or self-adhesive. It is also possible to cut out the trapezium elements so as to be able to fix their non-parallel edges by heat sealing. The rough shaped strips may be pre-glued before coiling or rolling.

Another aspect concerns the securing of the end disc on the horizontal inwardly turned flange at the small base of the capsule ; one may easily position and secure the disc with glue or other know means without, as previously having to position it inside the rough shape on the head of the frusto-conical mandrel : a larger surface is therefore available which, for example, is equal to that of the small base of the capsule. The discs can be cut out in a known manner from a metal or plastic strip brought into position in a known manner. The securing of the disc on the flange of the capsule may or may not be simultaneous and is effected by gluing the disc along the lower periphery by the base of the cutter, by securing with dabs of. glue on the inwardly turned flange, or by thermal melding during the end of the cutting path.

According to another aspect of the invention, the outer surface of the skirt of the capsule is provided with bosses, shape, number and arrangement differing from capsule to capsule. of five in number.

These. bosses are' obtained on the forming cones receiving the capsules in the machine, the forming cones having surface or shape,number' •and/or distribution differing from one another and corresponding to the bosses to be obtained.

According to a complementary embodiment, the bosses are extended along the skirt of the capsule by projections or flutes easing the introduction of air at the location for automatic positioning on the bottles.

During the forming of the capsules, the material conforms to the forming cone and the surface irregula- rities of the forming cone furnish the bosses. With a multi-station forming machine, the forming cones differ from one another by the arrangement and/or number and/or shape of their surface irregularities so that the corresponding bosses differ from one capsule to another.

An embodiment of a device is described hereinbelow enabling various aspects of the invention.

In the drawings : Figures la and lb show sectional views of a closure capsule in two steps of closing its small end on a mandrel, according to a particular mode of the method of the invention; Figs. 2a, 2b, 2c, 2d and 2e show five stages of the forming of a closure capsule according to the invention; Fig. 3 shows a capsule having three bosses; and Fig. 4 shows a capsule with three bosses extended by flutes. cone 10 with ... its annular notch 10 ' as well as the roug shape 8 with its small end 8 ' projecting about the small base of the frustoconica^nandrel. The heating device 12 bends the projecting sides of the end 8 ' over the SL_*11 base of the frustoconioal mandrel while forming (figure lb) an annular notch 8" at the flange. The capsule 19 is completed when the disc 16 is secured to the inwardly turned flange.

In the example of figure 2, from left to right is shown a continuous printed strip B which is displaced in the direction of the arrow F. In the vicinity of the mandrel 10, the strip B is cut transversely at B' so as to/orm flat rough shapes 8 (figure 2a ) . By any known means, for example suction, the rough shape 8 is turned through 90 ° and brought to position perpendicular to the direction of displacement F of the strip (figure 2b ) . The edge 9 at the right of the rough shape 8 is then cut as a circular arc 9 ' so that the rough shape can be rolled onto the conical shape of the mandrel 10 (figure 2b ) . The plane 8 is then rolled about the mandrel with its edges 6 glued (figure 2c ) then the projecting portion 8 ' is turned down (figure 2d ) at 8" and the disc 16 put into position so as to complete the capsule 19 (figure 2c ) .

Stored capsules 19 are latter brought in a known manner to a capping station where they are very easily picked up one by one owing to the small notch which connects the frustoconical surface to the disc.

In figure 3, the bosses 20 are adapted to prevent jamming in stacking or nesting the capsules. The number of bosses is a matter of choice. By way of example, a capsule may have three bosses, anothe^ capsule four bosses and a third capsule five bosses. It may also be provided with types of capsules having additional bosses or irregular arrangements of bosses relative to one another.

When the material is applied to the forming cone, it takes the exact shape of the latter and skrinks due to the heat stretching along the relief portions of the forming cones.

In figure a variation of the bosses is shown in which the bosses are extended forming a flute or an 21 elongated flange/facilitating the introduction of air at the location for automatic positioning on bottles.

Therefore, this invention enables to manufacture with a low cost capsules for capping practically in a single pass and without special working for cutting lengths or printing on conical rough shapes but nevertheless satisfying all commercial imperatives (low production cost, clear and fancy markings) and governmental imperatives (exact reproduction of seals, for ensuring the impossibility of re-use) even with starting strips which are thinner than usual.

Claims

CLAIMS : ~

1. A method of making capping or overcapping closure 2 capsules for containers of mono-oriented thermoshlnkable maten 3 having a frustoconical skirt with its axis perpendicular to J+ the direction of mono-orientation and a horizontal annular !3 bent-over portion at the small end of the skirt, said 6 method comprising the steps of : 7 a) providing a strip of (mono-oriented) thermoshrinkable 8 material stretched lengthwise; 9 b) displacing said strip lengthwise while it lies 10 horizontally flat; 11 c) cutting out blanks from said strip; 1 d) rotating each blank through 90° from the direction ->.> of displacement of said strip about a vertical axis; 1·: e) rolling the rotated blank into frustoconical shape; !■-> f) bending over the small end of the frustoconical 17 blank and closing the small end with a disc on the outside of 13 the bent-over portion. 1 2. Method according to claim 1, wherein the strip of ?. thermoshrinkable material provided is unrolled from a roll 3 of said material wound on a reel. 1 2. Method according to claim 1, further comprising

2. The additional steps of printing said strip and drying the

3. Printing medium before cutting out the blanks. - 10 - 42821/2

4. A method according to Claim 1 of making closure material having frustoconical skirt with its axis perpendicular to the direction of mono-orientation, and a horizontal annular bent-over portion at the small end of the skirt, said method comprising the steps of : a) providing a strip of mono-oriented thermoshrinkable material strechcd lengthwise; b) displacing said strip lengthwise while it lies horizontally flat; c) printing said strip and drying the printing medium while said strip is held under sufficient tension for preventing shrinkage thereof; d) cutting out blanks from said strip; e) rotating each blank through 90° from the direction of displacement of said strip about a vertical axis; f) rolling the rotated blank into frustoconical shape; and g) bending over the small end of the frustoconical blank and closing the small & ά with a disc- on the outside of the bent -over portion.

5. A method according to claim , wherein the tension applied to -said strip is provided by a force pulling said strip for displacing it lengthwise.

6. A method according to claim 1, further comprising the additional steps of printing said strip and polymerizing the printing medium before cutting out the blanks. 42821/2

7. A method according to Claim 1 of making closure capsules for containers of mono-oriented thermoshrinkable material, having a frustoconical skir with its axis perpendicular to the direction of mono-orientation, and a horizontal annular bent-over portion at the small end of the skirt, said method comprising the steps of : a) providing a strip of mono-oriented thermoshrinkable material stretched lengthwise; b) displacing said strip lengthwise while it lies horizontally flat; c) printing said strip and polymerizing the printing medium while said strip is held under sufficient tension to prevent shrinkage thereof; d ) cutting out blanks from said strip; e) rotating each blank through 90° from the direction of displacement of said strip about a vertical axis; f) rolling the rotated blank into frustoconical shape; and g) bending over the small end of the frustoconical blank and closing the small end with a disc on the outside of the bent-over portion.

8. A method according to claim 7, wherein the tension applied to said strip is provided by a force pulling said strip for displacing it lengthwise.

9. A method according to claim 1, wherein the mono-oriented thermoshrinkable material is selected from a group consisting of polyethylene and polyvinyl chloride. - 12 - 1

10. A method according to claim 1, further providing1 2 a frustoconical mandrel on which the blank is rolled into j* frustoconical shape, and heating the small end of | frustoconical blank projecting beyond the small base of the mandrel at an angle of 5° for bending over said (> small end of the frustoconical blank. γ

11. A method according to claim 10, wherein the 8 frustoconical mandrel is provided with an annular step 9 at its periphery adjacent its small base for providing 0 a corresponding annular step adjacent the small end of the 1 closure closed with a disc.

12. A method according to Claim 1 for manufacturing an overcapping closure capsule of mono-oriented thermoshrinkable material, the closure capsule having a skirt with an axis of revolution perpendicular to the direction of mono-orientation and an inwardly turned annular bent-over portion at the smaller end of the skirt, said method comprising the steps of : a) providing a strip .of thermoshrinkable synthetic material stretched in the lengthwise direction to achieve a mono-orientation; b) displacing the strip lengthwise in the direction of mono-orientation; c) printing the strip and drying the printing medium while the strip is under a stretching tension sufficient to prevent any substantial lengthwise shrinkage of the strip; d) cutting out blanks from the printed strip; e) rotating each blank through 90° from the original direction of displacement of the strip; g) bending over an annular portion of the smaller ^ end of the frustoconical blank; and h) closing the smaller end of the frustoconical blank with a disc on the outside of the annular bent -over portion.

13. A method according to Claim 1 for manufacturing an overcapping closure capsule of mono-oriented thermoshrinkable material, the closure capsule having a skirt with an axis of revolution . perpendicular to the direction of mono-orientation and an inwardly turned annular bent-over portion at a smaller end of the skirt, said method comprising the steps of : a) providing a strip of thermoshrinkable synthetic material stretched in the lengthwise direction to achieve a mono-orientation; b) displacing the strip lengthwise in the direction of mono-orientation; c) maintaining the strip under a stretching tension sufficient to prevent any substantial lengthwise shrinkage of the strip; d) cutting out blanks from the strip; e) rotating each blank through 90° from, the original direction of displacement of the strip; f) rolling the rotated blank into a frustoconical shape ; g) bending over an annular portion of the smaller end of the frustoconical blank; and h) closing the. smaller end of the frustoponical blank with a disc on the outside of the annular bent-over portion. 1

14. A method according to claim 5, wherein the tens¾pn 2 applied to the strip is provided by a force pulling said for displacing it lengthwise. 1

15. . A device for carrying out the method according to claim 10, comprising a plurality of frustoconical mandrels arranged in a multi-station forming machine, and • having surface irregularities, said surface irregularities 5 being different on each of the frustoconical mandrels.

16. A device according to claim 15 , wherein the number 2 of surface irregularities on the forming cones differs 3 from one another. 1

17. A device according to claim 15 , wherein the 2 arrangement of the bosses on the forming cones differs from J '' one another. 1

18. A devive according to claim 15 , wherein the shape of the bosses on the forming cones differs from . one another. Λ I

19. A device according to claim 15 , wherein the bosses are extended on the capsule skirt with an elongated flange making easier the air introduction at the location of the automatic positionning on bottles. 1

20. A device according to claim 15 , wherein the bosses are extended on the capsule skirt with a flute making easier the air introduction at the location of the I. -t automatic positionning on bottles. For the Applicants