NZ260544A - Bag forming; tape with reclosable elements affixed during bag formation from film material - Google Patents

Description

260544 Patents Form # 5 NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION TITLE : BAG ATTACHABLE SUPPORT AND RECLOSEABLE ELEMENT TAPE f APPLICATION#: 260544 FILING DATE: 17 May 1994 v ^ I ""ty'iiiss $ We,: Minigrip Flexible Packaging Limited Address: 27 Ross Reid Place, East Tamaki, Auckland, New Zealand Nationality: New Zealand > hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: PF05.JWP FEE CODE - 1050 26 0 5 a 4 This invention relates to apparatus and methods of fabricating plastic film bags in particular as part of and/or for utilisation in automatic bag forming and charging apparatus.

Traditionally bags having recloseable elements have been made in either of two ways. In a first method recloseable elements are integrally moulded with the Him from which the bags are subsequently formed. This approach involves blown film moulding techniques and thus tends to be limited to utilising polythene type plastics suitable for blow film moulding. In a second approach the recloseable elements are moulded as a separate strip which is attached to a parent film prior to bag fabrication. While this enables other plastic materials to be utilised for the film generally it also requires that the strips be moulded by an extrusion process. At least as a matter of capital expenditure this tends to be considerably more expensive than blow film moulding.

Difficulties have been encountered in adapting bags having an originally separate recloseable element strip to some vertically formed continuous bag forming and charging apparatus. With such apparatus the bags are fabricated as a first stage or alternatively simultaneously to the bags being charged. Design constraints within the charging apparatus have prevented or at least limited the use of such bags. Traditionally the strips are narrow and welded onto the appropriate faces of the material from which the bags are to be formed. To some extent the aforesaid problem has been overcome by extruding the separate strips with a substantially wider base. For convenience in distinguishing these wider strips from the traditional strips they are hereinafter referred to as tapes.

The tapes thus have extensive lateral flaps to either side of the recloseable elements. A tape tends to be more easily handled than a strip, the flaps being welded onto the bag film to become the top of the bags, that is, as an extension of each bag rather than onto the side of the bags as in the case with the strips. A draw-back with this tape approach is the expense as an even larger extrusion die is necessary than those required to form the strips. On the other hand to blow-form separate tapes with integral recloseable elements is not practical. This comes about as the constraints, in particular the practical minimal diameter of a blow-forming die, limits this being carried out effectively.

In a modification of this construction bag support means and/or recloseable elements May 199S/81S0CS.595/09 260544 are provided which are extruded as part of the bag to interconnect the bags adapting them for use in particular in what, for convenience, may be called vertical bag forming and charging apparatus. The support means interconnect a series of plastic bags, often referred to as a bag-chain, incorporating recloseable elements. The bag-chain is fed to an automatic charging and sealing apparatus following which the individual bags are severed from the chain. Typically the support means linking the bags includes at least one rail or similar means formed integrally with the bags to support the bags in their passage through the apparatus. The support rails may be adjacent either the top or bottom of the bags enabling the bags to be charged from the associated end.

Thus an object of this invention is to provide a method and apparatus of interconnecting and supporting a series of plastic bags rendering them suitable for utilisation within an automatic vertically disposed bag charging and sealing apparatus. While this invention is particularly directed to bags having recloseable elements it is envisaged it would also be suitable for utilisation with non-recloseable bags.

Accordingly in one aspect the invention consists in a method of forming a chain of interconnected bags or bag preforms comprising the step of providing one of a series of bags or material from which a series of bags will be formed and adhering at least one elongate element on said series of bags or material from which a series of bags will be formed to provide an interconnected chain of bags, the elongate element being shaped so as to provide a rail by which the bags can be passed through filling apparatus.

In a further aspect the invention consists in an interconnected chain of bags or bag preforms when formed by a method according to the preceding paragraph.

In a still further aspect the invention consists in an interconnected chain of bags or bag preforms, said bags or bag preforms having a pair of sides upon each of which is mounted an elongate member by which said bag may be supported, at least during filling of said bag or a bag made from said bag preform.

In a still further aspect the invention consists in a method filling a bag comprising the steps of forming a bag or bag preform as described above and/or providing an interconnected chain of bags or bag preforms as described above, supporting said bag or bag preform by means of said elongate member or members, opening said bag or bag ^ fcw T preform, closing and sealing said bag and optionally removing said elongate memberfc^ V\v J r>r JUL 1396 "I B1EOIPG1 7 96/CW/iv 260544 Preferred forms of the invention which will be considered in all its novel aspects will now be described with reference to the accompanying drawings which is given by way of example only and in which; Figure 1 is a diagrammatic side elevation of a series of interconnected bags according to one preferred form of the invention, Figure 2 is a diagrammatic cross-sectional view of the interconnected bags of 10 figure 1, Figure 3-7 are views of part of the bag of figure 2 in alternative constructions, Figure 8 is a diagrammatic perspective view showing the bags of figure 1, 15 for example, in use in one type of machine, Figure 9 is a view of part of the construction of figure 8 in an alternative view, and Figure 10 is a view as in figure 8 of a further alternative construction in use.

Referring to the drawings.

In the construction of figure 1 a series of interconnected bags 1 are provided. The series of interconnected bags 1 comprises a series of individual bags 2. The bags 2 may be formed from two sheets of plastic film or from a folded over single sheet in the known manner. A tape 3 carrying recloseable elements 4 is provided so that, for example, on one face of the bag a bulbous rib is provided and on the other tape a narrow mouthed channel so that the rib may be forced into the channel or pulled therefrom to allow the bag to be opened and closed.

The sheet is also interconnected by a tape 5, there being one tape 5 on each face of the bag. The tape 5 may be provided by two single tapes or alternatively the tape may be a single tape folded as shown pecked at 6 in figure 2. The tape carries at least one rail 35 and preferably a pair of rails 7 from which in the filling step the bag may be suspended and manipulated. In the construction shown in figure 2 the recloseable elements 4 are Hay 1995/B150CS.595/QA 260544 connected and the bag opened at the end carrying the rails 7. Where the tape is provided as a single tape the folded portion 6 is removed just prior to the bag being opened for filling. In the construction of figure 3 the bag is similar save that rails 8 are provided on the exterior surface of the tape 5.

^ In the construction of figure 4 strips 10 are provided rails 11 being provided on the strips 10. The construction of figure 5 is again similar save that the strips 10 and rails 11 are provided on the exterior surface of the bag.

In the construction of figure 6 rails 13 are adhered directly onto the bag walls. Again in figure 7 the construction is similar save that the rails 13 are provided on the exterior surface of the bag.

It will also be apparent that in like constructions, not shown, the tapes 5, strips 10 or rails 13 can be provided at the opposite end of the bag, that is to say adjacent what in the filled bag will be the mouth, that being the end carrying the recloseable elements 4. In such a construction the end of the bag remote from the recloseable elements 4 will be closed prior to filling.

In other embodiments of the invention the recloseable elements 4 themselves may fulfill the function of the rails 7, 8,11 or 13. The tapes 5, strips 10 or rails 13 are affixed to the film longitudinally as the film advances. Suitable welding techniques are provided with possibly both the tape strip or rail and the associated part of the film 25 being preheated prior to nip rollers pressing the two together. Once the tape 5 strip 10 or rail 13 has been applied the bags may be sealed and severed as at 16. It is desirable that the slit formed at 16 extend at least a short distance into the tape S where such a tape is provided. Thus a series of interconnected bags are provided which can be stored, for example, by zig-zag folding or rolling into a roll and which may then be 30 used on a filling machine as desired. It will be apparent that the filling machine and bag forming could take place in the same process line in which case the interconnected construction could be considered as an interconnected bag preform.

In use in the construction shown in figures 2-7 once the bag has been filled the parts of the bag substantially above the pecked line 18 are severed and the bag sealed.

Kay X995/8150CS.395/90 260544 Referring to figure 8 the bags may be used as follows. The chain of bags generally indicated at 1 are suspended from a rail 20 by means of the rails 7,8, 11 or 13. Indexing may be achieved, for example, by providing a mark 21 on the bag which is 5 sensed by a mark sensor 22. At station 23 the bag is opened and charged. The bag is then reclosed and passes between indexing drive conveyors 24 which take the charge bags to seal bars 25 to close the bag and past a knife conveyor 26 to remove, in the case of the bag of figure 2, for example, the tapes 5, rail 7 and unwanted parts of the bag walls as indicated at 27. In the construction of figure 8 the bags are held substantially 10 vertical. In the construction of figure 9 the apparatus is substantially the same save that at station 23 the bag is swung to a substantially horizontal position for charging before being returned to a vertical position for passing between the indexing drive conveyors 24.

In the construction of figure 10 the interconnected chain of bags 1 is supported initially by conveyors 30 so that at the charging station 23 the bag is horizontal before passing on to a further conveyor 31 and passing seal bars 25. In each case any required vacuum or gas flushing can be affected and the trimmed off tape is in many instances able to be returned for recycling.

The invention is used substantially as above described thus a chain of interconnected bags is provided which are able to be used as formed or stored for later use, the use comprising filling and sealing of the bags with associated vacuum or gas flushing as desired.

The preformed bags or bags are they are formed are able to be filled on appropriate equipment in a simple yet effective manner.

Thus it can be seen that a method of forming a chain of interconnected bags or bag 30 preforms and/or an interconnected chain of bags or bag preforms and/or a method of filling a oag are provided which have the advantage that the bags are able to be suspended particularly in vertical positions for charging but also in horizontal positions in a secure fashion. The supporting construction is able to be removed from the bag if desired in a simple yet effective manner.

K«y 1995/B150CS.595/00

Claims (16)

WHAT WE CLAIM IS: 260 544

1. A method of forming a chain of interconnected bags or bag preforms comprising the step of providing one of a series of bags or material from which a series of bags will be formed and adhering at least one elongate element on said series of bags or material from which a series of bags will be formed to provide an interconnected chain of bags, the elongate element being shaped so as to provide a rail by which the bags can be passed through filling apparatus.

2. A method as claimed in claim 1 wherein at least two elongate elements are adhered on said series of bags or material from which a series of bags will be formed, said elongate elements being positioned so as to provide at least one elongate strip on each side of said bag and in like positions.

3. A method as claimed in either claim 1 or claim 2 wherein said elongate element or elements are adhered directly > nio said bag material.

4. A method as claimed in either claim 1 or claim 2 wherein said elongate element or elements are provided on a strip of material (as herein defined) which strip of material is adhered to said bag.

5. A method as claimed in either claim 1 or claim 2 wherein said elongate element or elements are provided on a tape of material (as herein defined) which tape of material is adhered to said bag or bag preform.

6. A method as claimed in claim 5 wherein said tapes are positioned as an extension to the mouth or foot of said bag or bag preform.

7. A method as claimed in any one of the preceding claims wherein said elongated members are positioned adjacent, either the mouth of said bag or bag preform or the foot of said bag or said bag preform.

8. A method as claimed in any one of the preceding claims wherein said elongate members are formed of plastics material. ^ ^ r . •y'-V . B150ICLM. 996/CW/iv _ ' - 0 .. 260 54

9. A method as claimed in any one of the preceding claims wherein at least two elongate members are formed at least two elongate members being recloseable elements.

10. A method of forming a chain of interconnected bags or bag preforms substantially as herein described with reference to the accompanying drawings.

11. An interconnected chain of bags or bag preforms when formed by a method according to any one of the preceding claims.

12. An interconnected chain of bags or bag preforms, said bags or bag preforms having a pair of sides upon each of which is mounted an elongate member by which said bag may be supported, at least during filling of said bag or a bag made from said bag preform.

13. An interconnected chain of bags or bag preforms substantially as herein described with reference to the accompanying drawings.

14. A method of filling a bag comprising the steps of forming a bag or bag preform as claimed in any one of claims 1 to 10 and/or providing an interconnected chain of bags or bag preforms as claimed in any one of claims 11 to 13, supporting said bag or bag preform by means of said elongate member or members, opening said bag or bag preform, closing and sealing said bag and optionally removing said elongate members.

15. A method of filling a bag as claimed in claim 14 when dependent on claim 5 wherein said tape is removed from said bag.

16. A method of filling a bag substantially as herein described with reference to the accompanying drawings. JAMES W PHPER & CO Attorneys foi^Ehe Applicant Minigrip EJerable Packaging Limited B150ICLM.996/CW/lv