WO1994022721A1

WO1994022721A1 - Improved tabs and manufacture thereof

Info

Publication number: WO1994022721A1
Application number: PCT/GB1994/000721
Authority: WO
Inventors: John David Wood; Alan Kenney; Ian Michael Daines Gaylor
Original assignee: Cambridge Consultants Limited
Priority date: 1993-04-07
Filing date: 1994-04-05
Publication date: 1994-10-13
Also published as: AU6384294A; GB9307287D0; PL311004A1; EP0691915A1

Abstract

A tab for attachment to a product such as a tea bag comprises a paper envelope (30) which is separable into two portions (40a, 40b) by tearing along a line of perforation (7). The envelope accommodates a length of thread (14) which adheres lightly to the facing surfaces of the envelope and is attached more firmly to the strip on respective sides of the line of perforation (7). One (40b) of the portions is heat sealed to the tea bag so that when the portions are pulled apart the line of perforation (7) tears and the thread (14) is unravelled from within the opened envelope but the ends of the thread remain attached to the now separated portions. An apparatus and method are disclosed for continuously producing tabs from a length of carrier strip and for applying them to products such as tea bags.

Description

Titler Improved Tabs and Mannfactnre Thereof

This invention relates to tabs made primarily of sheet material such as paper or card and incorporating a thread, string or similar filamentary material.

The most familiar application of tabs of this sort is in tea bags which are commonly provided with a tag and thread by which the spent tea bag can be extracted from a tea cup or tea pot. One end of the thread is generally attached to the tag by a staple or by adhesive tape, and the other end of the thread is attached to the tea bag by being included in the edge seal of the bag or by means of a staple or adhesive tape. The exposed length of thread between bag and tag produces problems in handling and packaging because of the propensity for the lengths of thread to become entangled with their surroundings and with one another. The invention aims to provide a novel construction of tab in which the problems posed by exposed lengths of thread are overcome. The invention also provides a method of and apparatus for manufacturing such a new tab.

Disclosure of the Invention

According to one aspect of the invention there is provided a tab separable into two portions interconnected by a length of thread, comprising an envelope having a line of weakening, the envelope accommodating the thread in a folded or coiled condition, the thread being detachably adhered to each of two facing surfaces of the envelope with ends of the length of thread being secured in the envelope on respective sides of the line of weakening whereby, when the tab is separated into the two portions by rupturing along the line of weakening, the thread is detached from the facing surfaces of the envelope and the two resulting portions of the tab are interconnected by the length of thread. The term "thread" is used herein to include any suitable filamentary material (whether of natural or synthetic material, or a mixture thereof) including string, fibre or yarn.

The tab is thus extensible by virtue of the ability of the thread to unfold or uncoil from within the ruptured envelope.

The tab may be attached to a product, typical examples being domestic cleaning goods (eg toilet deodorisers), food products (eg boil-in-the bag foods), beverages and infusions (eg tea and coffee bags) or personal hygiene products (eg tampons). The tab on each product can lie in a compact manner against the product, the thread being neatly enclosed in the envelope. Alternatively, the tab may itself incorporate the useful product. For example, the thread could be dental floss which would be kept hygienically packed within its envelope until the user ruptures the envelope along the line of weakening and pulls out the floss ready for use. The attached tab portions would provide a convenient aid to using the floss.

Of these products, it is thought that infusion packages, particularly round infusion packages (for example made as disclosed in WO 90/13487 and WO 92/14649) are likely to be the most important commercial application of the invention.

According to another aspect of the invention there is provided a method of making a tab separable into two portions interconnected by a length of thread, comprising detachably adhering the thread to one surface of a carrier strip and folding the latter back onto itself to enclose the thread, in a folded or coiled condition, within an envelope having a line of weakening, the two ends of the length of thread being secured on respective sides of the line of weakening, whereby when the envelope is separated into two portions by rupturing along the line of weakening the two resulting portions of the envelope can be pulled apart, with attendant unfolding of the length of thread, to an extent dependent on the unfolded length of thread which interconnects the two portions of the envelope.

Preferably, the thread is applied, in a serpentine shape, to said one surface of the carrier strip such as paper or card. In a preferred method, the thread and the carrier strip are fed in a continuous process which produces a series of tabs. Where the tabs are to be applied to a product, the speed of production of the completed tabs conveniently matches the speed of passage of the products past a station at which the tabs are attached to the products.

Preferably, the carrier strip has fold and cut lines applied thereto at- appropriate intervals along its length, after which the thread is lightly adhered to one surface of the carrier strip and more firmly adhered at locations where the ends of the thread are to be secured in the - A - envelope, the strip and the attached thread then being folded, cut and sealed to form the envelopes.

According to a further aspect of the invention apparatus for making tabs each separable into two portions interconnected by a length of thread comprises first feed means for feeding carrier strip to an adhering station, second feed means for delivering thread to the adhering station and for applying the thread, in a folded, coiled or serpentine formation, to one surface of the carrier strip at the adhering station where the thread is caused to adhere to said one surface of the carrier strip, folding means for folding the carrier strip and the adhered thread so that areas of said one surface are brought together, and means for cutting and sealing the carrier strip with the thread applied thereto to form a plurality of envelopes each having a transverse line of weakening separable to form said two portions interconnected by a length of thread.

The first feed means preferably apply fold lines and lines of weakening to the carrier strip in alternate sequence, the fold lines and lines of weakening being applied at a predetermined spacing to suit the size of the required envelopes.

The adhering station preferably includes two rollers cooperating to form a nip between which the carrier strip and thread are fed in a continuous process, and in a preferred embodiment one or both rollers are heated to cause the thread to adhere lightly to the surface of the carrier strip, means being provided for increasing the strength of attachment of the thread to the carrier strip at spaced locations along the carrier strip where the thread is required to remain attached to the respective portions of the tabs. The attachment may be further enhanced locally by adding adhesive material at this stage in the process.

According to a yet further aspect of the invention there is provided a method of making tagged infusion packages in a continuous process, comprising placing a thread on one surface of a carrier strip, cutting the strip and folding the latter back onto itself to enclosse the thread, in a folded or coiled condition, within envelopes each joined to a projecting tab portion along a line of weakening extending transversely across the strip, and adhering the projecting tab portions to the infusion packages to provide the tagged infusion packages.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of apparatus for making the tabs and applying them to individual products.

Figure 2 is a diagram showing a length of carrier strip and applied thread prior to folding and cutting, and

Figure 3 shows an individual product with a tab attached thereto, the tab having been separated into its two portions interconnected by a thread.

Referring to Figure 1 , the apparatus is equipped with a reel 1 of a flexible substrate carrier strip such as paper, woven or non-woven fabric or thermoplastic film. The surface 2 of the carrier strip which is exposed as it is unwound from the reel 1 is coated with a hot melt material such as polyethylene, Surlyn or other lacquer. The carrier strip passes over three rollers providing a tension control loop 3 and then passes through the nip between two rollers 4, 5. The upper roller 4 has spaced ridges a first series 6 of which impart transverse lines of perforation 7 to the carrier strip and a second series 8 of which apply fold lines 9 across the strip. The two series of ridges 6 and 8 are arranged alternately in sequence around the roller 4 so that the fold lines 9 and perforated lines 7 are applied to the strip alternately in sequence, at spacings which suit the size of the eventual envelope to be made from the strip material.

The carrier strip then advances to an adhering station 10 where the strip passes into the nip between a pair of rollers 12, 13. A supply of thread 14, from a reel 15, is also delivered to the adhering station, the thread 14 passing through an eye on the end of an oscillating lever 16 before entering the nip between the rollers 12, 13. The oscillating movement imparted to the thread 14 by the lever 16 causes the thread 14 to be applied to the surface of the carrier strip in a serpentine pattern along the central region of the adhesive surface 2 of the strip, as illustrated in Figure 1. Instead of the oscillating lever 16, the thread 14 could be given its serpentine shape by means of a rotating guide.

One or both of the rollers 12, 13 are heated to heat the hot melt material on the carrier strip to near its softening point, with the result that the thread 14 is attached lightly to the surface 2 of the carrier strip in the zig-zag or serpentine form shown. The carrier strip, with the thread lightly adhered to one surface thereof. then passes into the nip between a second pair of rollers

17, 18 the purpose of which is to apply, at predetermined spaced intervals along the carrier strip, patches of tape 19. A supply of the tape from a reel 20 is delivered to the surface of the roller 18. The surface of the tape indicated at 22 in Figure 1 is coated with hot melt adhesive.

A rotating cutter 23, positioned adjacent the peripheral surface of. the roller 18, cuts the tape into the small patches 19 which are carried by the roller 18 into the nip between the rollers 17 and 18. The roller 18 is heated and the pressure in the nip between the roller 18 and the counter roller 17 causes the patches 19 to adhere to the carrier strip so that, when the carrier strip emerges from the nip between the rollers 17 and 18, the patches 19 overlie the thread at predetermined intervals along the length of the carrier strip. The thread is thus more firmly attached to the carrier strip at the locations of the patches 19.

Instead of having the pair of rollers 17, 18, the roller 13 may have around its periphery spaced pads which provide an increased heating effect and therefore cause the thread to be more firmly heat sealed to the strip at a series of regularly spaced locations. If required, additional adhesive material may be added at this point.

After emerging from the nip between the two rollers 17,

18, the strip, (after passing around a guide roller 24) passes a rotating cutter 25 carrying a blade and then encounters a roller 26 which causes the leading edge of the cut length of carrier strip to be folded back onto itself along a fold line 9. Figure 2 illustrates the surface 2 of the carrier strip with the applied thread 14 immediately prior to cutting by the cutter 25 and folding by the roller 26. The thread 14 is firmly attached to the carrier strip at spaced locations (corresponding to the patches 19) which straddle the positions 27 at which the strip will be cut by the cutter 25. Each leading edge 27a of the strip (with its applied thread 14) is folded about the leading fold line 9a to bring the edge 27a into register with the leading perforated line 7a, leaving an uncovered flap portion 28 between the line 7a and the immediately succeeding line of cut 27. Hence, the flap portion 28 is positioned on the end of the tab when the resulting envelope is cut along the next cut line 27. It will be appreciated that the leading fold line 9a is equidistant from the leading cut edge 27a and the leading perforated line 7a.

The resulting folded packages pass a roller 29 having spaced flanges which seal the side edges of the folded strip so as to form envelopes 30, each having a defined length of thread extending between the respective attachment points at locations 27. Each envelope 30 is then applied to the surface of the product. In the example of Figure 1, the products are circular tea bags 32 which are delivered in a continuous web 33 travelling at a constant speed in the direction of arrow 34. The envelopes 30 are attached to the tea bags by a heated roller 35, using the uncovered adhesive flap portions 28 of the envelopes. The speed of production of the envelopes matches the constant speed of passage of the tea bags passing the tab application station.

Each envelope is applied to the corresponding tea bag so that the adhesive flap portion 28 is adjacent the curved periphery of the corresponding bag overlying the peripheral heat seal of the bag. The advancing web 33 then encounters a roller 36 which folds each tag back upon itself about a fold line corresponding to the line of perforation 7. After folding, the web passes into the nip between a rotating cutting roller 37 (having circular cutting knives) and a rotating anvil roller 38 which act together to separate each circular tea bag, with its attached tag, from the surrounding waste tissue 39 of the web. This cutting operation removes corners of the tab, but leaves sufficient of the central portion of each line of perforation 7 for the tab to remain intact.

Each tea bag therefore has adhered to its surface a tab formed by the envelope with its corresponding length of thread 14 therein. The resulting tagged tea bags are compact and are ready for packaging. When a tea bag is used, the free, projecting end of the tab is pulled, the tab breaks along its transverse line of weakening defined by the corresponding perforated line 7, resulting in the tab separating into two portions 40a, 40b (Figure 3). Pulling the two portions 40a, 40b apart uncoils the length of thread 14, from within the now opened envelope, but the length of thread 14 remains attached to the respective portions because the ends are firmly sealed at the locations corresponding to the half patches 19. Each thread end is attached by means of half a patch 19, because each cut line divides a complete patch 19 into two halves. The tea bag 32 is immersed in water and the spent tea bag is retrieved by use of the portion 40a and thread 14.

Where the inventive tab constitutes or includes the useful product (for example where the thread is dental floss), two end portions of the strip (with attached thread) are preferably folded inwardly towards one another, meeting at a perforated line, typically producing an envelope having two separable portions of the same size. As before, the two portions are separated by tearing along the line of weakening and pulling apart, to uncoil the thread from within the envelope portions which remain interconnected by the uncoiled thread.

Claims

1. A tab separable into two portions interconnected by a length of thread, comprising an envelope having a line of weakening, the envelope accommodating the thread in a folded or coiled condition, the thread being detachably adhered to each of two facing surfaces of the envelope with ends of the length of thread being secured in the envelope on respective sides of the line of weakening whereby, when the tab is separated into the two portions by rupturing along the line of weakening, the thread is detached from the facing surfaces of the envelope and the two resulting portions of the tab are interconnected by the length of thread.

2. A tab according to claim 1, wherein the two ends of the thread are secured to respective surfaces of the envelope at locations adjacent to, and on respective sides of, the line of weakening.

3. A tab according to claim 2, wherein the thread is detachably adhered to each of the two facing surfaces of the envelope in a serpentine fashion.

4. A tab according to any of the preceding claims, wherein one of the portions is a projecting tab portion by which the tab is attachable to a product.

5. A tab according to claim 4 and in combination with a product in the form of an infusion package.

6. A method of making a tab separable into two portions interconnected by a length of thread, comprising detachably adhering the thread to one surface of a carrier strip, and folding the latter back onto itself to enclose the thread, in a folded or coiled condition, within an envelope having a line of weakening, the two ends of the length of thread being secured to the strip on respective sides of the line of weakening, whereby when the envelope is separated into two portions by rupturing along the line of weakening the two resulting portions of the envelope can be pulled apart, with attendant unfolding of the length of thread, to an extent dependent on the unfolded length of thread, which interconnects the two portions of the envelope.

7. A method according to claim 6, wherein the thread is detachably adhered in a serpentine shape to the surface of the carrier strip.

8. A method according to claim 6 or 7, wherein the thread and carrier strip are fed in a continuous process which produces a series of tabs.

9. A method according to claim 8, wherein the tabs are applied to a product and the speed of production of the completed tabs matches the speed of passage of the

-products past a station at which the tabs are attached to the products.

10. A method acording to any of claims 6 to 9, wherein the carrier strip has fold lines and weakening lines applied thereto at appropriate intervals along its length, after which the thread is detachably adhered to the surface of the carrier strip and more firmly adhered at locations where the ends of the thread are to be secured to the strip, the strip and the attached thread then being cut, folded and sealed to form the envelopes.

11. A method according to claim 10, wherein the strip is folded back onto itself to bring a cut line into register with a line of weakening so as to leave a projecting tab portion for the attachment of each tab to a product.

12. A method according to claim '11, wherein the tabs are applied to a moving web which incorporates the products, each tab portion being adhered to the web in such a position that the corresponding line of weakening lies adjacent an edge of the product, with the envelope projecting forwardly from the line of weakening with reference to the direction of movement of the web, the envelope subsequently being folded about said line of weakening so that the envelope overlies the tab portion and the corresponding product.

13. A method according to claim 12, wherein after the envelope is folded back about the line of weakening the web is cut to detach each product, carrying its corresponding tab, from waste areas of the web.

14. A method according to claim 13, wherein the products are round infusion packages and the cutting of the web cuts through end portions of the line of weakening leaving a central length of the line of weakening intact, ready to be ruptured when the user pulls the envelope away from the tab portion adhered to the product.

15. A method of making tagged infusion packages in a continuous process, comprising placing a thread on a carrier strip, cutting the strip and folding the latter back onto itself to enclose the thread., in a folded or coiled condition, within envelopes each joined to a projecting tab portion along a line of weakening extending transversely across the strip, and adhering the projecting tab portions to the infusion packages to provide the tagged infusion packages.

16. A method according to claim 15, wherein after adhering the tab portions to the infusion packages the envelopes are folded back to overlie the tab portions and the infusion packages to provide a compact arrangement.

17. A method according to claim 16, wherein the infusion packages are circular and are delivered in a moving web to a tab applying station where the tab portions are adhered to the web with each line of weakening closely adjacent to an edge of a circular infusion package, after folding back of the envelopes the circular infusion packages being cut from a web in a cutting operation which also trims the corners of the envelopes and the tab portions to leave the central portion of each line of weakening intact.

18. Apparatus for making tabs each separable into two portions interconnected by a length of thread, comprising first feed means for feeding carrier strip to an adhering station, second feed means for delivering thread to the adhering station and for applying the thread, in a folded, coiled or serpentine formation, to one surface of the carrier strip at the adhering station where the thread is caused to adhere to said one surface of the carrier strip, cutting means for cutting the strip, folding means for folding the carrier strip and the adhered thread so that areas of said one surface are brought together, and means for sealing the carrier strip with the thread applied thereto to form a plurality of envelopes each having a transverse line of weakening separable to form said two portions interconnected by a length of thread.

19. Apparatus according to claim 18, wherein the first feed means applies fold lines and lines of weakening to the carrier strip in alternate sequence, the fold lines and lines of weakening being applied at a predetermined spacing to suit the size of the required envelopes.

20. Apparatus according to claim 18 or 19, wherein the adhering station includes two rollers cooperating to form a nip between which the carrier strip and thread are fed in a continuous process.

21. Apparatus according to claim 20, wherein at least one of the rollers is heated to cause the thread to adhere lightly to said surface of the carrier strip.

22. Apparatus according to claim 21, wherein means are provided for increasing the strength of attachment of the thread to the carrier strip at spaced locations along the carrier strip where the thread is required to remain attached to the respective portions of the tabs.

23. A tagged infusion package having a tab produced by a method as claimed in any of claims 6 to 14.

24. A tagged infusion package manufactured by a method as claimed in any of claims 15 to 17.