GB2623051A - Li tie - Google Patents

Abstract

A thermoplastic bag design and method of manufacture comprising a parabolic perforation between each bag on a roll of said bags, such that a pair of pointed ears are formed at the top of each bag. Said ears are used to tie the bag shut. This has the benefit of each bag being able to tesselate with each other on the roll, thereby reducing waste. Pockets may be created in each of the ears to aid with lifting the bag.

Description

PATENT APPLICATION DESCRIPTION

PARABOLIC TIE BAGS

The claim relates to an environmentally efficient flexible bag design (mainly thermo plastic food bags, sacks, liners and carrier bags) that employs a parabolic shaped cut at the open end of the bag with 2 curved elongate and welded ears that are 'gained 'from the base of the preceding bag in the process. Each bag 'nests' into the next, and the same parabolic shape is employed at the base (welded/perforated end) of the product.

This eliminates the need to remove the large handle cut outs that a traditional tee shirt /carrier bag necessitates, by utilising the parabolic shaping and the largely unused bottom corners cf flat base bags to create the tie ears.

The problem with all existing bags (flat top, drawstring or tee shirt /carrier bag style) is that the products are produced from a flattened tube of film, and with a straight/horizontal base weld. The product is of course then opened into a circular mode. This results in unavoidable wasted areas of material at the bottom corners of said bags, be they gusseted or un-gusseted. The invention produces a rounded base, mirroring the shape of the round receptacles they are used in.

The tie ear length in all variants must be sufficient to provide a double knot capability and thereby to secure the contents of the bag (FIGURE 1, 2 & 7).

The claim then extends to various welding or cut out features to enhance the carry and /or tying of said bags.

DRAWINGS 1-11 (SEE ATTACHED) 1) WELDED TIP VARIANTS (FIGURE 1) This achieves pointed 2 ply ears for extra strength and lift out' pockets or handles beneath each welded area for easier manipulation and tying. and importantly the ability to cffer a slight throat restriction/grip round the rim of bins (FIGURE 9).

The production of this style bag is achieved in one welding process to simplify the manufacturing sequence (base welds and ear tip welds are produced at the same time with one welding bar (FIGURE 3).

With the welded ear 'tip' invention claim (FIGURE 1) the base weld features a similar parabolic shape but recuires a unique broadening of the welding bar profile at the upper end portion (tip) of each ear or top ends of the weld bar (FIGURE 3).

The claimed invention of the welded upper portion of each ear variant (FIGURE 1) also features the same (parabolic) perforation shape applied just below the base weld to cut through the broad welded section at the top I thereby producing a welded ear 'tip' for the next bag in the manufacturing sequence (FIGURE 3).

Alternatively a full cut can be applied to separate each bag entirely for interleaving or other manufacturing options.

It is further envisaged that the ear tip welds can be adjusted in terms of rake angle so as to slightly increase or decrease the size of the bags throat circumference. (FIGURE 8) 2) PUNCH HOLE/HORSESHOE PART CUT VARIANTS (FIGURE 5 &6) This alternative employs welded or un-welded incisions into each ear to perform a similar lift and de function to the ears of the bag.

With the welded variant this again offers the slight throat restriction and 2 ply strength benefits. Also in welding the 2 faces of each ear it results only one hole per ear having to be located to achieve the intended lift and tie function. Another variant of the invention would be to employ a large spot weld to each ear to achieve a similar 2 ply strengthening benefit and lift capability.

These punch out or horseshoe shaped cut variants (FIGURE 5 & 6) can be either welded to provide the throat restriction benefit and 2 ply strengthening of the tie ears (FIGURE 10), or un-welded to offer a simpler lift and tie feature for bin liner or lightweight carrier bag applications (FIGURES).

The only disadvantage of the un-welded versions is that there will then be 4 holes to be gathered together daring the lifting/tying process, and the danger of single holes being engaged in error. It does offer a simpler lift, carry and tie solution in some respects though.

The potential option of securing the bags with the use of rounded handles or hooks, built into the side of the bin itself, to which welded bag cut out or horseshoe shaped part cut versions can be secured (FIGURE 5,6 & 10).

ADDITIONAL CLAIMS/NOTES A further claim is that the welded tips and punch holes or part cut holes can be employed on the same bag (FIGURE 7). This for instance may offer some dispensing benefits if suspended on prongs and presented at point of sale.

The elongate tie handles of the invention must be wider as they curve inwards to intersect the body of the bag, so as to provide sufficient lift strength if the bag is removed from a bin and an overlapping or hooding of contents feature when the elongate tie ears are employed.

The same, or very similar basic dimensions/proportions of the ears in relation to the body of the bag/sack are deemed necessary for any size of product (FIGURE 1 & 7) in order to achieve the required double knotting.

This equates to approximately 20% of the total length of a given bag.

Any thing less than this will result in more of the body of the bag being employed to close the top of the bag over the contents adequately, so counter productive. A large refuse sack needs to cover a bigger span, hence the need for longer ears compared to a small freezer bag product for instance.

There is a further potential material saving with the invention compared to gusseted tee shirt style bags because it is only necessary to double knot the ears of parabolic shaped bags whereas the existing tee shirt handles are obliged to be of sufficient length to enable them to be employed as bin liners, and the gusseting of said bags means taey have to have exceptionally long handles to ensure they can be located over the rim of bins. This equates to a further inefficiency claim with existing bin liner products (tee shirt).

Most bins are themselves wider round the rim than the base of the bin to ease removal of bags from the receptacle, so the narrowing of the lower portion of the bag in the invention matches bin shapes to a great degree (FIGURE 9 & 10) The bottom corners of a conventional flat base bag are very often unfilled because they are being fitted to a circular bin and therefore get folded into the base of the receptacle when it is located in the bin With gusseted style bags the bottom corners produce wasteful external pockets, which in use folds down to produce a shaped base of sorts, but in a very inefficient manner compared to the invention.

PERFORATION PATTERN

A further claim in relation to the invention is with regard to the perforation curve of bags on the roll specifically.

A standard perforation pattern can be employecc(FIGURE 3), beneath the base weld, and this would also mirror the parabolic shaping, at the open end of the bag, however it may be beneficial to have variable spacing/length of cuts of the perforation at the outer and /or central portions of the parabolic shape This would aid removal from the roll and reduce any potential for the ears to tear when the product is being dispensed from the roll.

CARRIER BAG APPLICATION

The final claim in the invention is for a gusseted version (FIGURE 8). The dotted lines in this drawing indicate approximately where the internal gussets would be located.

There is the opportunity to vary the gusset depth to achieve different aperture features and handle configurations.

The handles in this variant would have 4 p[y ears for extra lift and carry strength.

The parabolic perforation bar must be positioned so that it cuts through each gusset just below the welded ears and an aperture is then created below each welded tip.

These apertures, and the welded tips of the ears, achieve a similar carrying feature to existing tee shirt style carrier bags (FIGURE 11), but can be employed as a bin liner as well.

This version of the invention, in its potential carrier bag guise, still avoids the need to recycle the large cut out that is required with existing tee shirt style liners/carrier bags, and significant material savings are achieved with the gaining of the carry handles from the base of the bag and a further reduction is achieved with the tapered ears of the invention in contrast to the'square' ears of existing tee. shirt style carrier bags.

It is alsp clairnpd that the welded ear tip would provide better lift strength than the flat par vir01 that is Currently employed for said tee shirt (carrier) style bags because of the greater depth of claimed parabolic handle tip weld.

Claims (8)

1. PATENT APPLICATION U TIECLAIMS SUMMARYThe invention describes an environmentally efficient thermoplastic bag/sack design that utilizes the bottom corners of the preceding bag in the manufacturing process to form a pair of welded tip or punch hole ears at the open end of the bag.The aperture (open end of the bag) is formed by a parabolic shaped cutter or perforating bar.A similar parabolic shaped weld is employed at the base of the bag, and in the case of the welded tip variant a more complex welding bar is required with 2 triangular extensions at the top (outer edges) of the parabolic base seal to provide the ears for the next bag in the process.The resultant 'nested 'bags' avoid any waste cut outs and thereby claims environmental efficiency status.INDIVIDUAL CLAIMS1) WELDED EAR TIP CLAIM (FIGURE 1) -Elongate ears, produced by the parabolic angled cutting or perforating to form the bag aperture, that are capable of being double knotted.- Pointed twin ears indicate a clear tying function.-Welding of upper portions of each ear provides 2 ply strengthening of each ear and presentation of a narrow tie for an even clearer tie function.- The welding of said ears provides a potential slight throat restriction to the mouth of the bag so that it will grip round the edge of the receptacle and reduce the possibility of the bag sliding into the bin (FIGURE 9).- A potential reduction in the number of manufacturing steps by the combining of the welded parabolic base of the first bag in the process and by utilizing triangular extensions at the top ends of the weld bar simultaneously producing the ears for the next bag using the same welding bar (FIGURE 3).- Lift pockets are created beneath each ear to aid lifting and manipulating of the bag into it's closed mode (FIGURE 2).-The parabolic welded base is also a unique feature of this style of bag and is a claimed part of the invention, and enables the efficient 'nesting' of one bag into the next in the process.
2. 2) WELDED FULL PUNCH OUT EAR APERTURE CLAIMS (FIGURE 5) -The same parabolic shape aperture.- Full punch out holes from each ear utilizing a hot knife to weld the ears into a 2 ply strengthened and narrow tie feature.- Resultant hole provides a clear lift and tie function to aid manipulation. ** * * * * * ** ** * 0 * * * ** * * * * * * * * * * 0 * * * * * * ** * * * * * 0 * * * * * * 0 3) WELDED/RETAINED-PART PUNCH EAR APERTURE CLAIMS (FIGURE 6) - Similar benefits to the full punch out variant 2) above except that the part cut roundel or horseshoe shaping is retained on the bag and thereby avoids mechanical removal in manufacturing.
3. - The retained part punch claimed benefit is that the punch itself is also heated and thereby provides the same 2 ply strengthening and potential throat restriction features.
4. 4) UNWELDED FULL OR PART PUNCH EAR TIP (FIGURE 5' & 6).- This claimed variant offers a simpler manufacturing option while still retaining the unique parabolic shaping to both the aperture and welded base of the bag.- The only downsides are that the ears do not have 2 ply strengthening and that there will be 4 punch apertures created (2 in each ear). This might lead to only one hole being located when assembling the tie ears and potential tear risk. However would be suitable for lightweight appliCations.
5. 5) SPOT WELDED EARS CLAIM - A similar effect could be produced by utilizing a large spot weld on the upper section of each ear to again provide the benefit of 2 ply strength and throat restriction features.
6. 6) GUSSETED VARIANT CLAIMS (FIGURE 8 & 11) -This variant introduces gussets into the mix, which provides 4 ply tie or lift ears.There are two apertures created inside the top of each gusset and beneath each welded ear tip, which offers the same benefits of a traditional carrier bags or indeed tie handle refuse sacks, but avoids the need to remove the large rectangular cut out that is part of the process for this current style of bag.The CO2 emissions calculations are again improved dramatically.-The elongate welded ear tip feature is claimed to improve the lift strength of the invention over current narrow bead carrier bag handle welds.
7. 7) VARIABLE PERFORATION PROFILE CLAIM -While it is quite feasible for a standard perforation profile/pattern to be employed, with the parabolic shaping of course, it may be of benefit in some manufacturing processes, to utilize a variable perforation pattern. This may ease dispensing from the roll and reduce any possible tearing of the ears.
8. 8) COMBINATION WELDED EAR TIP/PUNCH HOLE CLAIM,(FIGURE 12) -It is envisaged that both welded ear tips and punch holes can be utilized on the same bag in some situations.-Possible in store dispensing eyelet holes for hanging at point of sale locations (FIGURE 7).-Would provide the ultimate version of the invention by having the welded strength of the ears tips with an easy lift and tie feature of the full or part punch apertures (FIGURE 12) These can be located either just below the welded tip (FIGURE 7), or actually within the welded ear section itself (FIGURE 12). *O * * * * * ** * * * * * 0* **** * * **** * * * * * ** * * ****S