WO2014123411A1

WO2014123411A1 - Apparatus for pre-applying a strap handle to a continuous web

Info

Publication number: WO2014123411A1
Application number: PCT/NL2014/050066
Authority: WO
Inventors: Hendrik Jan Van Den Berg; Ronald Batenburg; John DUINMEIJER
Original assignee: Otium Packaging Technology Bv
Priority date: 2013-02-05
Filing date: 2014-02-05
Publication date: 2014-08-14
Also published as: NL2010246C2

Abstract

An apparatus is disclosed for adhering a strip of a first flexible material to a continuous web of a second flexible material. The apparatus comprises a means for gripping the strip; a means for folding the end portions of the strip; and a means for adhering the folded end portions of the strip to the continuous web. The end portions are folded so as to become perpendicular to a center portion of the strip. The end portions of the strip are adhered to the continuous web while the strip is being held by the gripping means. The first flexible material can be a strap handle material; the second flexible material can be a bag-making material. The means for gripping may engage the end portions of the strip, in which case the means for gripping may also be the means for folding. In an alternate embodiment the means for gripping may engage the center portion of the strip.

Description

APPARATUS FOR PRE- APPLYING A STRAP HANDLE TO A CONTINUOUS

WEB

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The invention relates generally to an apparatus for attaching a strip of a first flexible material to a continuous web of a second flexible material, and more particularly to applying a strap handle to a film of bag-making material.

2. Description of the Related Art

[0002] In our earlier patent application NL 2008045, filed December 27, 2011, entitled "Bag with Pre- Applied Strap Handle" we disclose a bag having a strap handle that crosses the top seal of the bag. Our earlier invention is particularly suitable for implementation on a horizontal or vertical form-fill-seal machine. The strap handle is flush against the bag forming material during the forming and sealing stages, so that is does not interfere with the forming, filling or sealing of the bag. Upon completion of the bag the strap handle pops up across the top seal of the bag, so it may fulfill its handle function. The strap handle may be pre-applied during the manufacture of the film material, or on the fill-form-seal machine during the bag making process.

[0003] The pre-applied strap handle has a central portion extending in the cross machine direction of the web, and two end portions extending in the machine direction of the web, or v.v. Thus, the end portions are at a 90° angle to the central portion. The end portions are adhered to the web material; the central portion is substantially unadhered to the web material.

[0004] Our earlier patent application describes methods for pre-applying the strap handles to the bag-forming material. It is desirable to automate the process, preferably in a way to meet the normal speeds of film manufacture or bag making. Although technologies and apparatuses are available for adhering strips of a flexible material, such as labels and reinforcement strips, to a continuous web, the need for partially adhering strips at end portions that are at an angle from a central portion poses particular challenges. [0005] EP 2 397 318 Al discloses a handle-forming machine that applies handles to a continuous web of paper or plastic film. Strips of handle material are folded into a U- shape in a cradle, and then transferred to a loader. During this transfer grippers associated with the cradle release the handle, while grippers associated with the loader grab it. This transfer requires delicate synchronization of the loader with the cradle, and is a source of potential mishaps. [0006] Thus, there is a particular need for an apparatus for applying strips of a flexible material to a continuous web that does not require a transfer from a folding station to a loading station.

BRIEF SUMMARY OF THE INVENTION

[0007] The present invention addresses these problems by providing an apparatus for attaching a strip of a first flexible material to a continuous web of a second flexible material, said strip having a center portion and two end portions, said apparatus comprising: means for gripping the strip; means for folding the end portions of the strip into a direction that is substantially perpendicular to the center portion of the strip; means for adhering the folded end portions to the continuous web while the strip is being held by the gripping means.

[0008] In an embodiment the gripping means grip the end portions of the strip, so that the gripping means can carry out the folding action. [0009] In an alternate embodiment the gripping means grip the strip at the central portion, for example near the areas where the strip is to be folded. In this embodiment the means for folding the end portions is separate and distinct from the gripping means.

[0010] The means for adhering the folded end portions to the continuous web can be any suitable means known in the art. Adhesion may be accomplished by welding, adhesive, in particular hot melt adhesive, two-sided adhesive tape, and the like.

[0011] The apparatus can be adjusted to handle between 5 and 100 strips per minute, preferably from 30 to 80 strips per minute.

[0012] The apparatus can be integrated with film manufacturing equipment, or with a bag forming machine. BRIEF DESCRIPTION OF THE DRAWINGS [0013] The features and advantages of the invention will be appreciated upon reference to the following drawings, in which:

[0014] FIG. 1 is a perspective view of an apparatus according to the invention.

[0015] FIG. 2 shows the apparatus of Figure 1 after it has just received a strip of flexible material.

[0016] FIG. 3 shows the apparatus of Figure 2 after end portions of the strip have been folded.

[0017] Figure 4 shows the apparatus of Figure 2 from an opposite angle, when the strip reaches means for adhering.

[0018] Figure 5 shows the apparatus of Figure 4 with some of the means for adhering removed for clarity.

[0019] Figure 6 shows the apparatus of Figure 4 as the adhered strip is leaving the apparatus.

[0020] Figure 7 A shows an alternate embodiment of the invention.

[0021] Figure 7B shows the apparatus of Figure 7 A as a means for adhering applies heat and pressure to end portions of a strip.

[0022] Figure 7C shows the apparatus of Figure 7A as an adhered strip is leaving the apparatus.

[0023] Figure 8A is a perspective view of an alternate embodiment of the invention.

[0024] Figure 8B is a side view of the apparatus of Figure 8 A.

[0025] Figure 8C is a top view of the apparatus of Figure 8 A.

DETAILED DESCRIPTION OF THE INVENTION

[0026] The following is a detailed description of the invention.

[0027] In its broadest aspect the present invention relates to an apparatus for attaching a strip of a first flexible material to a continuous web of a second flexible material, said strip having a center portion and two end portions, said apparatus comprising:

means for gripping the strip;

means for folding the end portions of the strip into a direction that is substantially perpendicular to the center portion of the strip;

means for adhering the folded end portions to the continuous web while the strip is being held by the gripping means. [0028] The means for gripping the strip can be any suitable means known in the art. Examples include clamps, pincers, suction cups, and the like. The gripping action may be mechanical (as in clamps or pincers), magnetic, pneumatic, adhesive, and the like. As will become more clear in the following discussion, the gripping action must be amenable to be controllably released.

[0029] The strip has a central portion and two end portions. The end portions must be folded so as to extend at a 90° angle from the central portion, in the plane of the strip. The folded end portions are to be adhered to a continuous web of bag-forming material. The bag-forming material can be any material known in the bag-forming art. The material may be a polymer film, for example polyolefin, in particular polyethylene (PE) or polypropylene (PP); or polyester, such as polyethylene terephtalate (PET), or comprise bands or strips of such film material.

[0030] The strip is suitably made of a polymer film material. The width of the strip must be such as to comfortably fit a person's hand when the strip is used as a carrying handle. The strip must be strong enough to support the weight of the bag and its contents, which may vary from less than 100 grams (in the case of lifestyle bags) to a kilogram or several kilograms (in the case of agricultural products, such as potatoes, oranges, onions, etc., or bulk household products, such as powder detergents, flour, and the like) to 5 kilograms or more (in the case of potting soil, fertilizer, cat litter, and the like). Because of the need to provide sufficient strength, the strip material may be relatively stiff, which poses particular challenges for the folding action.

[0031] In an embodiment, the gripping means engages the strip at the end portions. Suitably the gripping means comprises a pair of grippers, each gripper of the pair engaging one end portion of the strip. The two grippers may engage the strip simultaneously or sequentially. In this embodiment the gripping means provide the folding action, for example by rotating over 90°, thereby folding the gripped end portion of the strip over 90°. During the folding action the two grippers move toward each other over a distance substantially equal to the width of the strip. In this embodiment the means for gripping are also the means for folding.

[0032] Preferably, in this embodiment the gripping means press the end portions of the strip onto the continuous web of bag-forming material at the start, and optionally also during the step of adhering the end portions of the strip to the continuous web. To make this possible the grippers should engage the strip on only one side, being the side facing away from the continuous web. Examples of suitable grippers for this purpose include magnets, adhesive pads, suction cups, and the like. As such one-sided grippers offer less control over the end portions of the strip than do two-sided grippers, such as clamps or pincers, one sided grippers are more suitable for relatively flexible strip materials, as less force is required for making the 90° fold.

[0033] In an alternate embodiment the gripping means comprises one gripper, which is capable of traveling back and forth between the two end portions of the strip. The gripper first engages a first end portion of the strip, applies the fold and presses the first end portion to the continuous web for adhesion. The gripper then moves to the second end portion, and applies the fold and adhesion to it. In this embodiment it is desirable to control the central portion of the strip, for example by adhering it to the continuous web with a glue bead, or by holding it in a clamp.

[0034] Instead of engaging the end portions of the strip, the gripping means can be designed to engage the central portion of the strip, leaving the end portions free. In this embodiment two-sided gripping means are preferred, as these offer greater control over the strip than do one-sided gripping means. Preferably the gripping means engages the central portion near the end portions, so that the gripping means assists in the folding action.

[0035] The folding may be accomplished by moving the end portions over forming surfaces. For example, the gripping means may engage the strip in a position perpendicular to the plane of the continuous web. The gripping means then rotate over a 90° arc to position the strip in a plane parallel to plane of the continuous web. During this 90° rotation the end portions are guided over forming surfaces to accomplish the desired folding.

[0036] After the folding action the end portions are adhered to the continuous web by applying pressure and/or heat, using means for adhering well known in the art.

Adhesion may be accomplished by welding, pressure sensitive adhesive, hot melt adhesive, two-sided tape, and the like.

[0037] Strips of handle material can be fed to the apparatus by any suitable means. For example, pre-cut strips may be provided in a cassette, and fed from the cassette to the apparatus by means well known in the art. In an alternate embodiment, strip material may be provided as a continuous ribbon from a reel, and cut to the desired length just prior to being fed to the apparatus. In yet another embodiment the strips are cut transversely from a continuous web, the web having a width corresponding to the desired length of the strip. This embodiment is preferred, as it allows for a large number of strips to be provided from a single reel, thereby reducing the changeover frequency.

[0038] Adhesion may be accomplished by any method suitable for the materials used. Examples include the use of welding, hot melt adhesive, pressure sensitive adhesive, two-sided tape, and the like.

[0039] Conveniently the apparatus comprises a drum having gripping means, means for folding and means for adhering associated therewith. The apparatus may have two gripping means positioned at 180° from each other. A full rotation of the drum contains two full cycles of the strip adhesion process. If the drum rotates at a speed of R rpm, the production rate of the apparatus is 2 x R strips per minute. The cycle time is 60/(2 x R) seconds. Thus, if R is 30 rpm the production rate is 60 strips per minute, and the cycle time is 1 second. The adhesion step desirably has a duration of at least 0.1 second, preferably at least 0.15 seconds. Thus, a production rate of up to 100 strips per minute is possible. Generally the production rate is from 5 to 100 strips per minute; preferably from 30 to 80 strips per minute.

[0040] It may be desirable to register the position of the strip with respect to the continuous web. Any suitable means may be used for this purpose. Methods known in the art for controlling the position of labels, reinforcement strips and the like are particularly suitable. Examples include the provision of visible or invisible markers on the web, which are tracked with laser pulse, visible light, u.v. light, or the like.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS/EXAMPLES

[0041] The following is a description of certain embodiments of the invention, given by way of example only and with reference to the drawings.

[0042] Referring to FIG. 1, an apparatus 40 is shown for adhering a strip 10 to a continuous web 20 of a bag-forming material. The web 20 is depicted as being fully transparent, so as to not obscure underlying features. It will be understood that the web may be made of an opaque material, and/or covered with printed text and pictures.

[0043] Continuous web 20 is guided by drum 30, which rotates in clock-wise fashion, as seen from left to right. The direction of rotation is shown by arrow 31. Strip 10 is shown after it has been adhered to web 20, and is about to leave apparatus 40. [0044] Drum 30 drives the other moving components of apparatus 40 via drive belt 32. Axis 33, driven by drive belt 32, drives left hand part 50 of a strip feeding mechanism. On the opposite side of apparatus 40 belt 32a drives right hand part 51 of the strip feeding mechanism.

[0045] Belt 32 also drives axis 34, which drives gripping means 60 (not shown in Figure 1). Another belt (not shown) drives axis 35 of sealing mechanism 70. Sealing mechanism 70 is designed to travel along with drum 30 guided by guide slots 71 and 72. Drum 30 is driven by an external motor (not shown) by means of drive shaft 36.

[0046] Figure 2 shows the apparatus of Figure 1, at the same point in its cycle. For clarity Figure 2 does not show drum 30 or strip feeding mechanism 50, 51.

[0047] At the depicted stage of the cycle, strip 10 has been adhered to web 20 and is about to leave apparatus 40. Strip 11 has just been picked up from strip feeding mechanism 50, 51 (not shown in Figure 2) by grippers 61 and 62. Strip 11 has central portion 14, and end portions 12 and 13. At this stage end portions 12 and 13 still extend longitudinally from central portion 14. At this stage also, the plane of strip 11 is perpendicular to the surface of drum 30 (not shown in Figure 2). Cam disc 63 is about to commence a clockwise rotation (as seen from left to right) of gripper 62. At the opposite side of apparatus 40 is an identical cam disc (not shown), which is about to commence a clockwise rotation of gripper 61.

[0048] At this stage also, strip 11 is immediately in front of forming surfaces 81 and 82. End portions 12 and 13 are about to be pulled into the spaces defined by drum 30 (not shown) and forming surfaces 81 and 82, respectively.

[0049] Figure 3 shows the apparatus of Figures 1 and 2, at a slightly later stage of the cycle. Grippers 61 and 62 have made a 90° turn, and have also moved backwards (from the perspective of the viewer) along with drum 30 (not shown). End portions 12 and 13 have been folded as a result of their having been pulled along forming surfaces 81 and 82, respectively, and are now pointing towards the viewer, perpendicular to the central portion (not shown). The plane of strip 11 (not shown) is now parallel to the plane of drum 30 (not shown).

[0050] Figure 4 shows the apparatus of Figures 1-3, but from an opposite angle. Strip 11 has just reached the position of sealing beam 73. Axis 35 starts rotating in clockwise direction, thereby pressing sealing beam 73 against strip 11, via action of levers 76, 77 and adjustable rods 74, 75. Rotation of axis 35 also starts movement of sealing beam in sync with the surface of drum 30 (not shown), along guiding slots 71, 72. Sealing beam 73 has heated pressure pads (not shown) at the positions of the end portions of strip 11 (not shown).

[0051] Figure 5 shows the apparatus of Figure 4, but with sealing beam 73 removed so that strip 11 is now fully visible.

[0052] Figure 6 shows apparatus 40 at the stage of the cycle where sealing beam has almost reached the end of its travel along guiding slots 71 and 72. Strip 11 (not shown) is now adhered to web 20 (not shown). Grippers 61, 62 are releasing strip 11 (not shown). At the opposite side of the drum (not shown) a second pair of grippers (not shown) are about to receive a new strip from strip feeding mechanism 50, 51 (see Figure 1), and the cycle recommences.

[0053] Figure 7 shows a semi-exploded view of an alternate embodiment. Apparatus 140 comprises a drum 130, driven by drum axis 136. Continuous web 120 is transported over drum 130. Figure 7A shows strip 110 clamped in gripping means 160.

[0054] Gripping means 160 comprises two strips of metal shaped like the intended shape of the central portion of strip 110, including diagonal edges 161 and 162. Axis 134 of gripping means 160 is rotated around drum 130 by means of arms 163, 164. Opposite from gripping means 160, at a 180° angle relative to drum axis 136, is a second gripping means (not shown).

[0055] Cam follower 161 is rotatably connected to axis 134. In the starting position shown in Figure 7A strip 110 is perpendicular to drum 130. As cam follower 165 moves around cam disc 131 in clockwise fashion, cam follower imposes a 90° rotation onto axis 134, so that strip 110 becomes parallel to drum 130. During this rotation strip 110 is pulled over the forming surfaces 181, 182 (only forming surface 181 is shown in Figure 7A, for clarity).

[0056] Discs 171, 172 press web 120 against drum 130. Discs 171, 172 are mounted on an axis (not shown), the rotation of which is synchronized with that of drum axis 136 by a mechanism that is not shown. Discs 171, 172 comprise heated portions 173, 174 [0057] Figure 7B shows strip 110, the folded end portions 112, 113 are engaged by heated portions 173, 174 of discs 171, 172. The pressure and heat supplied by discs 171, 172 provides adhesion of end portions 112, 113 to web 120. [0058] Figure 7C shows strip 110 with its folded end portions 112, 113 firmly adhered to web 120. At the opposite side of drum 130 a corresponding gripping means just received the next strip (not shown in Figure 7C).

[0059] Figure 8A shows a perspective view of apparatus 240. Apparatus 240 comprises a rectangular box 241; each side of rectangular box 241 supports two suction cups 242, 243. Suction cups 242, 243 are movable in transverse direction along slots 244, 245. In addition, each suction cup is rotatable around its axis, in stepped rotations of 90°. Box 241 is rotatable around its axis 246, in stepped rotations of 90°.

[0060] Each suction cup is connected to a vacuum source and to a compressed air source. In use, a pair of suction cups receives a strip of flexible material (not shown) so that the end portions of the strip are engaged by the suction cups. At this stage vacuum is applied to the suction cups. So that the suction cups grip the strip.

[0061] Figure 8B shows a side view of apparatus 240. Box 241 supports suction cups 242a, 242b, 242c, and 242d (suction cup 242d is not visible). Suction cup 242a receives an end portion of a strip (not shown), which it engages by means of vacuum applied to suction cup The other end portion of the strip is engaged in like fashion by corresponding suction cup 243a (not shown) at the opposite end of box 241. After gripping the strip, box 241 rotates clockwise over 90° around its axis 246, so that suction cup 242a takes up position 242b (while suction cup 242b takes up position 242c, etc.). During this rotation suction cup 242a rotates around its own axis over 90°, and suction cup rotates 243a rotates around its axis over 90° in opposite direction. At the same time suction cups 242a and 243a move toward each other over a distance equal to (or slightly in excess of) the width of the strip. During this time vacuum continues to be applied to suction cups 242a and 243a, so that the end portions of the strip continue to be gripped by the suction cups. The respective rotations of suction cups 242a and 243a, combined with their movements toward the center of box

241results in the desired folding of the end portions of the strip.

[0062] When this movement is complete, suction cups 242a and 243a (having taken the positions of suction cups 242b and 243b, respectively) are pressed against a continuous web (not shown). Heating blocks on the opposite side of the web apply heat, so that the end portions of the strip are adhered to the continuous web. After the adhesion step is complete, compressed air is applied to the suction cups in positions 242b and 243b, so that the strip is released. [0063] In the meantime the suction cups that are now in positions 242a and 243a take up the next strip, starting the next cycle. As these suction cups rotate to positions 242b and 243b, suction cups 242b and 243b move to positions 242c and 243c. At the same time these suction cups slide outward toward the ends of box 241, so that they are once again in the correct positions to receive the end portions of a strip.

[0064] Figure 8C shows a top view of apparatus 240. Suction cups 242a and 243a have just received a strip (not shown). Box 241 starts rotating, so that suction cups 242a and 243a will take up positions 242b and 243b, respectively. During this rotation suction cup 242a will be pushed toward the center of box 241 through slot 244, and suction cup 243a will be pushed toward the center of box 241 through slot 245. This lateral movement causes suction cup 242a to rotate counter-clockwise over 90° by the action of chain 247. At the same time suction cup 243a is rotated clockwise over 90° by the action of chain 248.

LEGEND to FIGURES

10, 11 strips

12, 13 end portions of strip 11

14 central portion of strip 11

20 continuous web

30 forming drum

31 arrow showing direction of rotation

32 first drive belt

32a second drive belt

33 axis of strip feeding mechanism

34 axis of gripping means

35 axis of seal mechanism

36 drive shaft of drum 30

40 the apparatus

50 left hand part of strip feeding mechanism

51 right hand part of strip feeding mechanism

60 gripping means 61 left hand gripper

62 right hand gripper

63 cam disc

70 sealing mechanism

71, 72 guide slots

73 sealing beam

74, 75 adjustable rods

76, 77 levers

81, 82 forming surfaces

110 strip

1 12, 113 end portio s of strip

120 continuous web

130 drum

131 cam disc

134 axis of gripping means

136 drum axis

140 apparatus

160 gripping means

161, 162 diagonal edges

163, 164 arms for moving gripping means

165 cam follower

171, 172 means for adhering

173, 174 heated portions

181, 182 forming surfaces

240 apparatus

241 rectangular box

242, 243 suction cups

242a,b,c,d suction cup positions

243a,b,c,d suction cup positions

244, 245 slots

246 axis of box 241

247, 248 chains for rotating suction cups [0065] Thus, the invention has been described by reference to certain embodiments discussed above. It will be recognized that these embodiments are susceptible to various modifications and alternative forms well known to those of skill in the art. For example, the gripping means can be given any convenient form. Many ways are known in the art to accomplish folding of a flexible strip. Adhesion may be accomplished by applying heat and pressure (for example in case adhesion involves welding or a hot melt adhesive), or by applying pressure alone (for example in case adhesion involves pressure sensitive adhesive or two-sided tape). Other modifications may be apparent to those skilled in the art, and are considered part of this invention.

[0066] Many modifications in addition to those described above may be made to the structures and techniques described herein without departing from the spirit and scope of the invention. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. Apparatus for attaching a strip of a first flexible material to a continuous web of a second flexible material, said strip having a center portion and two end portions, said apparatus comprising"

a. means for gripping the strip;

b. means for folding the end portions of the strip into a direction that is substantially perpendicular to the center portion of the strip;

c. means for adhering the folded end portions to the continuous web while the strip is being held by the gripping means.

2. The apparatus of claim 1 wherein the gripping means engage the strip at the end portions. 3. The apparatus of claim 2 wherein the gripping means comprises a pair of

grippers, each gripper gripping one end portion of the strip.

The apparatus of claim 3 wherein the grippers serve the function of the means for folding.

The apparatus of claim 4 wherein the grippers move toward each other while folding the end portions of the strip.

The apparatus of claim 4 or 5 wherein the grippers rotate over 90° while folding the end portions of the strip.

7. The apparatus of any one of claims 2 to 6 wherein the gripper comprises suction cups.

8. The apparatus of claim 1 wherein the gripping means engages the center portion of the strip, leaving the end portions free.

9. The apparatus of claim 8 wherein the means for folding the end portions comprises forming surfaces that fold the end portions as the strip is moved over the forming surfaces.

10. The apparatus of claim 9 wherein the gripping means grip the strip in a position perpendicular to the continuous web, and moves the strip to a position parallel to the continuous web, thereby moving the end portions over the forming surfaces to fold the end portions.

11. The apparatus of any one of the preceding claims wherein the means for

adhering press the end portions of the strip against the continuous web.

12. The apparatus of claim 11 wherein the means for adhering apply heat to the end portions of the strip.

13. The apparatus of claim 11 or 12 wherein the means for adhering apply pressure and/or heat to the end portions during a time of at least 0.1 seconds.

14. The apparatus of claim 13 wherein the means for adhering apply heat and

pressure to the end portions during at least 0.15 seconds.

15. The apparatus of any one of the preceding claims which operates in a

continuous fashion.

16. The apparatus of claim 15 which attaches strips of a first flexible material to a continuous web of a second flexible material at a rate of from 5 to 100 strips per minute. Preferably from 30 to 80 strips per minute.

17. The apparatus of any one of the preceding claims wherein the end portions of the strip are adhered to the continuous web using welding, hot melt adhesive, pressure sensitive adhesive, or two-sided tape.