GB2460435A - Thermal guard for an oven shelf - Google Patents

Abstract

A thermal guard 1 comprises a tube slit linearly along its length in a sinusoidal 3 or dovetail (7, fig.4) pattern, so as to enable the thermal guard to be attached to an item which is to be thermally isolated. The thermal guard is also provided with a plurality of annular rings or radial fins (2, fig.2) arranged along the length of the tube so as to form an accordion or concertina-like pleated outer surface. This form of outer surface is designed to reduce the contact surface area and therefore minimise the heat transferred when the guard is touched by a person using the thermally isolated item. The guard can be made from a fluorosilicone polymer or other heat resistant insulating material. The guard may be formed integrally with the item to be protected, during its manufacture. Preferably, the thermal guard is used for thermally isolating an oven shelf 5, where the tube is of sufficient length to fit over the front bar 4 and support bars 6 forming parts of the shelf. In use, the thermal guard is designed to reduce or prevent personal injury by thermally isolating the front bar of an oven shelf.

Description

IMPROVEMENTS TO OVEN SAFETY

THERMALLY ISOLATING OVEN SHELF GUARD

This invention relates to protective coverings for oven shelves or racks to prevent burns.

Background to the invention. The danger of placing one's hands into an oven need not be overestimated, and there are few people who have cooked food in an oven who have not burned their hands or forearm. The current invention makes the front rail of any individual shelf within the oven cool enough to touch without damage. It will therefore find favour with many uáers of ovens and will improve the safety of using them. Indeed it may become a requirement under the Health and Safety laws of the UK that such protection be provided as due diligence on the part of the employer towards their staff.

There is little prior art in the field, but the lapsed patent GB 2373308 BILLETT claims a thermal guard for at least partially isolating a member about which it is installed, formed from an elongate spiral. This wraps around the front face of the tray or shelf within the oven and thereby protects the user from damage from the hot metal of the shelf. In use it would not be completely effective, however, and would be time consuming and awkward to put in place on the shelf. In GB 2412428 PIKE a similar approach to the problem is made using a tube formed of heat resistant silicone which is horizontally split in a zigzag formation and formed with lengthwise

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raised portions in the manner of a star shaped extrusion, to lessen the surface contact with the user's skin. This is intended to be wrapped around the front face of the shelf to the same effect as the former invention. The star shaped extrusion presents a greater protected area than that of BILLETT but also a greater surface area than the annular rings proposed herein. The greater surface area increases the amount of heat transferred to the user in case of accidental contact. In an earlier appiication by the surrent inventor GB2434202 UNWIN proposed a shelf protector that covered the entire surface of the shelf. In a subsequent application GB0724293.6 UNWIN an invention was proposed that formed the basis for one embodiment contained herein and is incorporated by reference thereto. The current invention is an improvement in terms of efficiency and versatility, distinguished from the instances of prior art by virtue of the surface features of annular rings arranged along its length and the form of the gap or slit whose form co-operates with the circular bars of the shelf where they meet and are attached to the transverse front or leading bar. The form of the gap or slit may be sinusoidal in character or formed in a dovetail pattern familiar to those skilled in woodwork, being a pattern of interlocking wedge shapes. In addition said gap or slit may be formed with its median line tangential to the inner circle of the tube or along the median line parallel to the axis of the tube or in any position between these extremes. The current invention provides for the annular rings to be circular in shape or alternatively in a second embodiment the rings are extended to form vestigial ribs in the manner of a comb on one side of the above mentioned gap or slit. Said vestigial ribs may further be linked by a thin sheet of material in the form of a web similar to the foot of an aquatic bird.

In this embodiment it is preferred that the gap or slit is formed in a straight line tangential to one side of the inner diameter of the hollow tube of heat resistant material. -According to the present invention there is provided a means of reducing or preventing personal injury by thermally isolating the front or leading bar of an oven shelf, wherein there is provided a tube formed of a material having high temperature resistance. The invention consists of a tube of sufficient length to encase the front or leading bar of a typical oven shelf from side to side, having an outer surface covered with annular rings forming radial fins to reduce surface contact between a user and the material. The invention is further equipped with a lengthwise cut, slit or gap formed either in a sinusoidal or dovetail pattern to enable attachment to the front or leading bar of the shelf by substantially conforming to the spacing of the linear support bars of the shelf where they attach to the transverse front bar. This enables a greater portion of the tubular form to bear upon the bar of the shelf and thus remain in position thereon. In a further embodiment as described above the annular rings are extended on one or both sides of the said gap or slit in order to increase the protection provided to the user. The extended ribs thus formed project from the tube towards the rear of the shelf when fitted to the leading rail of the shelf.

Therefore by covering the leading portion of the longitudinal rails of the oven shelf where they attach to the leading transverse rail the user is less likely to contact any of said leading portion of the shelf rails. In this embodiment it will not be necessary to form the gap or slit in dovetail or sinusoidal form on the tube as the provision of a gap or slit tangential to the inner diameter of said tubular form serves to hold the guard in place upon the leading rail in most cases. The alternative is to position said gap or slit towards the centreline of the tubular form. The extended ribs may in addition be linked by a thin sheet of material in the manner of a webbed foot.

The material forming the covering has the properties of chemical inertness and heat resistance, low friction co-efficient and easy cleaning coupled with resistance to chemical corrosion, moisture, mildew and fungus, Ultra-Violet, Infra-Red, and microwave radiation with outstanding electrical, insulative and di-electric properties.

This material would typically have an inner diameter of 8 millimetres and an outer diameter of 12 millimetres, with radial fins or annular rings extending typically a further 3 millimetres making a typical outer diameter of 18 millimetres. The typical length of the invention to suit a conventional domestic oven will be 360 millimetres, but this may vary in production for different applications, and ideally the oven would be provided with a thermal guard for each individual shelf therein. Said radial fins are arranged side-by-side lengthwise along said tube in the manner of accordion pleats in order to improve the ability of the length of tube to conform to any given shape of rail while presenting a very low surface area to transmit heat, thereby protecting the user of the oven. Further protection is provided by extending the annular ribs in a rearward direction as described above, and optionally linking them with a thin sheet to form a web as described above.

While a gap in the tubular form is required to affix said form to the leading rail of the oven shelf the versatility of the invention is improved by forming said gap or slit in a * sinusoidal or dovetail shape along its entire length. This provision effectively conforms to the support bars of the oven shelf where they attach laterally to the transverse front bar, usually offset above or below the said front bar. The sinusoidal or dovetail shapes each conform to differing arrangements of said support bars to enable the maximum adhesion between the guard and the heated metal. In the specific embodiments featuring extended annular rings said gap or slit may be formed in a straight line tangential to the inner circle of the tube. However, each of these embodiments refer to a guard that is designed as an accessory to an item such as an oven shelf. The invention applies equally to such a guard made integrally with the item prior to sale, e.g. when the guard is moulded in situ upon the oven shelf, perhaps as a complete covering. Such a development would naturally occur if the invention was widely accepted by the public and should fall within the ambit of

this patent if not prefigured by prior art.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows the basic method of arranging the covering around the shelf: Figure 2 shows the essential features of the invention: Figure 3 shows the co-operation between the sinusoidal curves of the lengthwise slit and the circular bars of theshelf.

Figure 4 shows the dovetail form of the lengthwise slit.

Figure 5 shows a sectional side view of the invention where the annular rings have been extended axially to one side of the s'it or gap.

Figure 6 shows a plan view of the extended annular rings linked by a web of material.

Referring to the drawings, Figure 1 shows the guard 1 in place upon the front bar 4 of the shelf 5. Support bars 6 attach laterally to the front bar 4 and are accommodated by the sinusoidal slit 3 that also permits the guard to be attached to the front bar 4 of the shelf 5 by opening and elastically closing to revert to its original shape thereby encasing the front bar 4 and the ends of the support bars 6.

Figure 2 shows the guard I equipped with annular rings 2 and sinusoidal slit 3 lengthwise. While the guard 1 is shown in a straight form it will be understood that the flexible nature of the material, and the annular rings 2 provided will enable the guard 1 to conform to a wide variety of shapes.

Figure 3 shows the method of arranging the guard I around the front bar 4 of the shelf 5 wherein the longitudinal support bars 6 forming the shelf are attached to the transverse front bar 4. The sinusoidal slit 3 conforms to the circular form of the support bars 6 where they attach to the front bar 4, whether the said support bars 6 attach above, below or at the same level as the front bar 4.

Figure 4 shows the guard I and annular rings 2 as in Figure 3 attached to the front bar 4 of the shelf 5 but in this case said guard I features a dovetail slit 7 wherein the co-operating wedge shaped portions 11 of the guard 1 interlock in order to hold the guard 1 firmly in place upon the bar 4. The bars 6 of the shelf 5 (not shown) are accommodated by the wedge shaped portions in a similar fashion to Figure 3.

Figure 5 shows a sectional side view of the guard I where the annular rings 2 have been extended axially to one side of the gap or slit 9 to form extensions 8 to the annular rings 2. Said annular rings 2 may equally be extended on both sides of the said gap or slit 9 to attach above and below the bar 4. The front bar 4 and side bar of the shelf 5 have been shown for clarity. In this embodiment the gap or slit 9 is indicated as a straight line form. The said gap or slit 9 may be positioned in any position between that shown on the centreline of the guard I and a position tangential to the inner diameter of the guard 1.

Figure 6 shows a plan view of the top of the guard 1 shown in Figure 5 featuring annular rings 2 extended on one or both sides of the gap or slit 9 to form extended annular rings 8. In this case the extended annular rings 8 are joined on one or both sides of the gap or slit 9 by a web 10 of the same material as the guard 1 in order to increase the protection afforded by the guard 1. The guard I is shown attached to the front bar 4 of the shelf 5 and the lateral rails 6 of the sheff 5 are shown emerging beneath the web 10 between the extended annular rings 8. It is thus shown that several embodiments of the same invention are to be envisaged.

While the invention has been disclosed in its preferred forms, it is to be understood that the specific embodiments thereof, as described and illustrated herein, are not to be considered in a limited sense, as there may be other forms or modifications of the invention which should also be construed to come within the scope of the appended claims.