GB2487092A - Oven basket with PTFE tape seams - Google Patents

Abstract

A basket 7 for cooking food is constructed from a sheet of flexible temperature resistant mesh 1, with corners formed by folding the mesh and connecting adjacent sides by means of PTFE tape, welding or other means. The corners may be joined welding a PTFE or similar fluoropolymer patch on one or both sides of the material at the corner, welding a vertical fluoropolymer strip 8 at the corner or welding a horizontal or vertical fluoropolymer strip around the corner, welding a fluoropolymer strip around the entire edge to form a hem, embedding the joined surfaces in a molten material such as silicone or forming a strip of molten material to the same effect, or using separate connecting means such as a helical spring, a clip or by means of weaving a length of heatproof material between the warp and weft of the two adjacent portions of material.

Description

NON-STICK COOKERY BASKETS CONSTRUCTION AND METHOI OF USE

This invention relates to the cooking of food items using a container made from a flexible heatproof material that allows free circulation of air to the surface of the foodstuff.

Any given foodstuff can be heated in either a conventional oven or in a microwave oven. However, a suitable container for loose items such as potato chips that allows air to circulate freely while cooking and is flexible for easy removal of the foodstuff is not evident in the marketplace. Trays available for use in a microwave oven are not capable of withstanding the higher temperatures encountered in a conventional oven. Moreover, they are not designed to allow the free circulation of air around the foodstuff while cooking, which increases the crispness and improves the quality of the finished article.

A further use for the current invention is in connection with open air cooking, whether on a barbecue range or over a campfire. The materiat will withstand the high temperatures encountered provided care is taken not to overexpose said material to direct flame. Burgers, steaks, sausages and many other food items may be successfully cooked in this manner with increased ease of handling near the heat source. A further benefit is the reduced chance of injury from burns due to the low thermal conductivity of the chosen material.

In an earlier application 0B0520391 UNWIN the inventor set forth a basket for use in a conventional or microwave oven that was found to be similar to the prior invention of W02005/065457 TURBOCHEF in that it featured substantially vertical peripheral walls. Said earlier invention is hereby incorporated by reference thereto. Other cited inventions were: GB 1159021 MERGER, US 5232609 PREVOST, GB 2082939 SANYO, FR 2505142 PAVAILLER and GB 2220346 PERKINS.

The current invention differs both in shape and construction from these instances of prior art. There are numerous instances of items that perform the function of containing foodstuffs within an oven but none of which feature the desirable qualities of the invention here set forth. The horizontal and vertical axes of the mesh are aligned in tine with the form of the basket (unlike the tray of TURBOCHEF) in order to give greater flexibility if folded along the main axis of the basket. Being formed as a basket and not as a tray having rigid side walls it provides benefits to the user in transferring the cooked foodstuff to another receptacle by allowing the mesh material to fold along the centre line. The user then may tip the basket so that the foodstuff is able to slide into a further receptacle for service. However, the dimension of the strands of the mesh is sufficiently large that while being lifted the basket maintains adequate rigidity to retain the foodstuff without additional support. The material is formed with a coating of one or a plurality of members of the fluoropolymer family well known for their low friction characteristics such as PolyTetraFluoroEthylene (or PTFE.) It is noteworthy that the mesh shown in the TURBOCHEF patent is indicated at forty-five degrees to the form of the tray.

A search of prior art disclosed W02005/065457 TURBOCHEF and GBI 159021 MERGER, which if taken together would render a tray formed of silicone as known. The few silicone-based mouldings suitable for use in the oven or microwave have a much higher ratio of surface-to air than the loose mesh presented here, thus presenting a restriction to the air circulation that makes the finished food less crisp. In the case of oven chips this can seriously detract from the quality of the finished product. A further benefit of the present invention over existing baking trays and containers is that its low thermal conductivity allows for the early removal of the container from the oven or other heat source without the usual risk of burning the hands.

The method of cooking using the present invention consists of the stages of: placing the foodstuff (e.g. potato chips) into the basket; placing the basket into the heating appliance or environment (e.g. oven or open fire); applying heat thereto for the appropriate length of time and turning the foodstuff therein as required; removal of the basket from the heating means and; removing the foodstuff from the container by allowing the concave form of the basket to fold centrally when holding in both hands thus forming a chute for the food, down which the food will slide when the basket is tipped.

According to the present invention, there is provided a basket formed from a sheet of glassfibre or other temperature resistant mesh having horizontal and vertical warp and weft, coated with PolyTetraFluoroEthylene or other fluoropolymer or silicone compound having high temperature resistance coupled with low friction coefficient and light weight. In order to allow circulation of air the mesh of the substrate must be sufficiently widely spaced that an air gap exists between strands of weft and warp, with an ideal size of 4-5 millimetres. It has been found that an increased air gap greatly increases the air flow over the food product and therefore improves the result, making e.g. chips much crisper. The size of the basket may vary to suit the application but will generally be within the range of sizes suitable for a domestic oven, e.g. less than 400 mm. square and 100 mm. in height, but in general use approximately 300mm. long and 250mm wide. The invention will thus improve the quality of cooked foodstuffs in a variety of high temperature environments by increasing the ventilation afforded to the foodstuff. The product is also both lightweight and has a low thermal conductivity. ln order to optimise the rigidity of the material the individual strands are of a diameter between 1.5 millimetres and 3.5 millimetres and are aligned with the main axes of the basket.

In order to form the basket, a square or rectangular sheet of mesh material having been defined, a notch or slit may be formed in the material a certain number of interstices from each corner by cuffing or removing a number of strands so that the flap thus formed can be rotated to overlap the adjacent side forming a double layer when brought together and conjoined. In this way the corner upstands are formed and the flexibility of the material provides a gentle basket-like side wall giving a gentle curvature from the centre of the basket to the edges thereof. The structure thereby formed may be held together in a variety of ways such as welding a PTFE or similar Fluoropolymer patch on one or both sides of the material at the corner, similarly welding a vertical Fluoropolymer strip at the corner or welding a horizontal or vertical

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Fluoropolymer strip around the corner, welding a Fluoropolymer strip around the entire edge to form a hem, embedding the joined surfaces in a molten material such as silicone or forming a strip of molten material to the same effect, or using separate connecting means such as a helical spring, a clip, rivets or poppers or by means of weaving a length of heatproof material between the warp and weft of the two adjacent portions of material.

A preferred embodiment is formed from a square or rectangular sheet of fibreglass mesh coated with PTFE (PolyletraFluoroEthylene) forming a non-stick sheet which is adapted at its corners by removing a square of material so that when the corners are folded together they will form upstands. These upstands are joined by welding or heat sealing a layer of the same material on one or both sides of the sheet at the corner seam. The sides thus formed may be further strengthened by attaching a ribbon of the same material by similar means along the peripheral edge of the sheet providing a solid border to the basket. The ribbon may be applied on one or both sides of the sheet at its edge.

A further method of attachment of the corners of the side walls comprises a spring or similar helical form which is helically threaded around two co-aligned strands of mesh into the spaces between warp and weft of the material, parallel to the top edge formed as described above. This naturally presumes that the material is cut squarely along the warp and weft of the material, and forms a secure connection between the adjacent sides that enables the formation of raised corners thus creating the three-dimensional form of the basket. The spring or helix will be of a similar pitch to the mesh size of the material, and may be formed of any material, although the preferred material is stainless steel. By this means an effective connection may be formed by simply spinning the spring helically onto the material and if necessary securing the ends of said spring to prevent its release.

Similarly, said connection may be effected by weaving a thread or strand of material through the above mentioned spaces between warp and weft in such a way as to hold the adjacent edges together. It has been found that a length of silicone string of a suitable diameter when threaded through the material will adhere to the said material without further means of securing. The corners of the basket may also be formed by other means. They may be inwardly cut at an angle of 45 degrees, said cut defining the height of the upstand at each corner. In high volume production it is anticipated that welding or similar adhesion of the corner flaps will be utilised in preference to other methods above described.

The present invention provides a means of effectively heating a range of foodstuffs without limiting the flow of air to the surface of the foodstuff. It is also easy to handle with minimal protection and conveniently shaped to move the contents when cooked to a separate bowl or plate. When removing the basket from the heat source with both hands it is sufficiently rigid to support the weight of the foodstuff, yet when unloading the basket it is simple to fold the left-and right-hand sides inwardly and upwardly to let the weight of the foodstuff deform the basket downwardly so that when tipped, the food slides into the desired receptacle.

Specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing, in which: Figure 1 shows a preferred embodiment of the basket; Figure 2 shows the means of forming the corner joint Figure 3 shows other means of securing the corner joints.

Referring to Figure 1, the fabric mesh I is formed into a container by means of creating slits or notches 2 near the corners 3 of the sheet of mesh 1. The edges of the sheet are then drawn together and connected by a patch or tape applied vertically across the seam 4 to form a corner 3 defining an upstand 6 and thereby forming a basket 7. A ribbon 8 of material is also applied to one or both sides of the peripheral edge of the basket 7 to form a border 9 thus providing increased rigidity. As explained in the description, other effective means of conjoining the adjacent edges are not excluded. Because the mesh I is aligned with the edges of the basket 7 the basket is enabled to fold centrally while retaining sufficient rigidity to contain the foodstuff, whereas if the mesh is aligned diagonally the basket will tend to fold from corner to corner.

Referring to Figure 2, as mentioned earlier the sheet of material is cut at each corner along the lines of warp or weft so that when strands 10 of the mesh 1 are removed to form an aperture 2 with edges 11 and 12. When edges 11 and 12 are placed together they form an upstand 6 that may be sealed by applying a patch or tape 5 as described earlier. Alternatively a single cut defined here by e.g. the doffed line 14 may be made to leave a flap 13. The flap 13 so formed may be overlaid onto the adjacent section of mesh land flap 13 is preferably overlaid on the inward side of the other section of mesh I to present a neater finish. It will be obvious that such a manipulation will form a vertical section or upstand 6 at each corner of the proposed basket 7 and providing rigid corner sections while allowing flexibility in the form of said basket 7 and thus permitting easy handling of the foodstuffs. This is of particular utility when removing the foodstuff as this may be achieved by folding and tipping of the basket.

Referring to Figure 3, further methods of forming the corners 3 are shown.

The basket 7 is shown in cutaway form for clarity. As described in Figures 1 and 2 the fabric mesh I is formed into an upstand 6 by means of folding the flap 13 against the adjacent section of mesh I thus bringing the adjacent sides together after cutting said fabric mesh 1 to form a notch 2. The weave will be found to align vertically in such a manner that a spring 15 of suitable pitch may be threaded helically through the gaps between warp and weft to form the corner 3. The spring 15 is preferably inserted vertically but may equally be inserted horizontally or diagonally, being rotated into place within the mesh and thus holding the basket form together. In place of spring 15 a clamp 16 may be utilised, which is crimped around at least two individual strands of material to hold flap 13 in place against the adjacent section of mesh 1. The clamp 16 is also illustrated in its flattened form showing tags 17 which fold round the adjacent strands 10 of mesh 1. Other methods of securing the upstand 6 such as rivets, clamps, poppers or rivet-like pop connectors may also be used to the same end and are not hereby excluded.

Having described the preferred embodiment of the present invention, modifications and improvements thereon will become apparent to those skilled in the art. Accordingly, the scope of the present invention should be construed broadly and only limited by the appended claims.