GB2113827A

GB2113827A - Stretch gaskets

Info

Publication number: GB2113827A
Application number: GB08300612A
Authority: GB
Inventors: Anthony Peter Lewis; Thomas Shakeshaft
Original assignee: SILICONE FABRICATIONS Ltd
Current assignee: SILICONE FABRICATIONS Ltd
Priority date: 1982-01-23
Filing date: 1983-01-11
Publication date: 1983-08-10
Also published as: GB8300612D0; GB2113827B

Abstract

For ease of fitting to an oven or other door 27 or door frame, the hollow extruded elastomer strips 14, 15, 16, 17 which provide surfaces 22, 23, 24, 25 for sealing against the door 27 and a confronting body frame or surface are integrally connected at respective mitred joints 18 to provide a one-piece stretch gasket 13. A fastener, e.g. in the form of an integrally moulded deformable button 19 or a curved hook carried by a right- angled metal strip inserted within the elastomer strips, projects from each corner of the gasket 13 for engagement in a respective hole 26 in the door 27. <IMAGE>

Description

SPECIFICATION Stretch gaskets This invention concerns stretch gaskets such as are used, for example, in the sealing of oven doors, and the like movable components, relative to the oven or like structures on which they are pivotally mounted.

It is already known to fit stretch gaskets to oven and like doors or, as is more often the case, to faces of ovens or similar bodies onto which said doors close. These gaskets comprise individual lengths of extruded hollow heat-resistant elastomer stripping, four such lengths being provided one adjacent each edge of the door. Each stripping length is provided, for example, in its ends with a hook-like fastener for engagement into a respective hole in the oven door, or the body frame of the oven onto which the door may close.

The length of each strip between the fasteners thereof is just very slightly less than the spacing between the corresponding holes, with the result that each strip has to be stretched in order to fit it in place, and after fitting, tension in each strip serves to ensure that the fasteners remain hooked in their holes.

It will readily be understood that with these known arrangements, each of the four lengths of stripping has to be cut to length and then fitted with its fasteners prior to fitting which involves the engagement of eight fasteners into their respective holes. Moreover, of course, the fasteners have to be appropriately shaped, or other means such as adhesive has to be provided, to ensure the fasteners remain anchored in their stripping lengths. Moreover, at each corner, one stripping length has to extend past the other to achieve a seal at the corner. This can involve substantially design problems.

An object of the present invention is to provide a stretch gasket construction whereby the abovediscussed difficulties are obviated or minimised only a single component, involving the engagement of only one fastener at each corner thereof, being required to seal a door, so that the actual fitting of the gasket is simplified and can be achieved quickly and does not involve any sealing problems at the corners.

With this object in view, the present invention provides a stretch gasket for an oven or other door or for the body frame of an oven or other structure onto which the door closes, comprising a piurality of hollow extruded elastomer strip members of cross-section providing surfaces for sealing against a door surface and the confronting body frame surface, characterised in that the said strip members meet and are integrally moulded at each corner of the gasket and in that a respective fastener projects from the gasket, at each corner thereof, for engagement into a respective hole in the door.

Each fastener is preferably in the form of a button which is integrally moulded with the gasket and is deformable so that it can be snapped into its respective hole. The form of each button is advantageously such as to provide a relatively narrow stem on which is a frusto-conical head.

Alternatively, however, each fastener may be in the form of a hook projecting from a corner of the gasket. Each such hook is conveniently integral with a retainer located within a hollow gasket and projects through a hole in the wall of the gasket intended to abut the door or the body frame.

The form of each retainer is preferably bifurcating so as to provide a part or prong extending through each of the two hollow strip members which adjoin at each corner of the gasket.

The cross-section of each strip member is preferably of oval configuration providing walls which are approximately parallel to one another and face the door and the oven or other structure, the fasteners projecting from the wall which is intended to be firmly attached to the door or the body frame.

The cross-section is preferably also such as to provide, along each edge of the aforesaid attachment wall, flexible narrow lips for engagement with the abutting surface of the door or body frame and/or along one edge of the other wall a wide tongue for engagement with the body frame or door respectively on which the gasket is not to be permanetly fitted.

The invention will be described further, by way of example, with reference to the accompanying drawing, in which: Fig. 1 is a fragmentary perspective view illustrating an oven of which the door is fitted with a first practical embodiment stretch gasket of the invention; Fig. 2 is an enlarged view of the stretch gasket of Fig. 1; Fig. 3 is a diagrammatic sectional view, enlarged as compared with Fig. 2, illustrating the cross-section of same embodiment of the stretch gasket and the manner of its fitting to the oven door, the section corresponding approximately to the line Ill-Ill of Fig. 1;; Fig. 4 is a diagrammatic sectional view, enlarged as compared to Fig. 3, illustrating a cross-section of a second practical embodiment of a stretch gasket according to the invention, at a corner thereof, and the manner of its fitting to the oven door by way of a hook member; Fig. 5 is a front view of one embodiment of a hook member to a reduced scale as compared with Fig. 4; and Fig. 6 is a front view of another embodiment of a hook member also to a reduced scale as compared with Fig. 4.

Referring firstly to Fig. 1, the oven shown therein comprises an open-fronted body structure 10 to which a door 11 is swingably connected by hinges 1 2. For sealing the door 11 relative to the body 10, a first practical embodiment of the stretch gasket of the invention, indicated generally by the reference numeral 13, is provided on the inner surface of the door 11 so as to extend along the four sides of the door 11 at a small spacing from the edges thereof.

As can be seen in detail in Fig. 2 the stretch gasket 1 3 comprises four hollow extruded strip members 1 4, 1 5, 1 6 and 1 7 which together form a rectangle, the ends of each said member being integrally connected to its neighbour at a respective mitred joint 1 8. This connection can be achieved by established techniques, for instance by locating the abutting mitred strip member ends into an appropriately shaped mould (not shown) and causing fusion at the confronting or abutting faces, if appropriate with additional material being added. In the moulding, a respective fastener in the form of a button, indicated generally by the numeral 19 in Figs. 2 and 3, is caused to be integrally-moulded with the corner of the gasket.

The strip members 14 to 17 and the button 19 are made of the same material, more particularly a heat-resistant elastomer, and as can be seen each button 1 9 comprises a narrow stem or neck 20 provided at its free end with a frusto-conical head 21 which tapers away from the strip members The cross-section of each strip member is approximately elliptical or oval in configuration (see Fig. 3) providing approximately planar and parallel rear and front walls 22 and 23 respectively and a central enclosed space 29. In the fitted condition of the gasket, the rear wall 22 faces the confronting inner surface of the oven door 11 and the front wall 23 faces away therefrom. The buttons 1 9 project from the rear walls 22 and serve to secure the gasket in place as will be described shortly.

The said cross-section is also such as to provide, along the two edges of the rear wall 22, respective resiliently deformable narrow lips 24 which seal with the door 11 by pressing thereagainst. Along the outer edge of the front wall 23 is a relatively wide tongue 25 which resiliently overhangs the adjacent oval portion and is of arcuate configuration providing a curved outer surface for abutting against and sealing with the front of the oven body structure 10.

The manner of fitting the stretch gasket 1 3 to the inner surface of the oven door 11 will readily be understood from the foregoing. For such fitting, four holes 26 (Fig. 3) are provided through an inner panel 27 of the door 11, on near each corner thereof. The lengths selected for the four strip members 14, 1 5, 16 and 1 7, are such that the spacing between the buttons 1 9 is slightly less than the corresponding spacings between the respective holes 26. As a consequence, the strip rembers have to be stretched very slightly during the fitting, which is effected simply by pressing each of the four buttons 1 9 through its respective hole 26.In each case the head 21 deforms to snap through the hole 26 and thereafter holds the respective corner of the gasket in place.

Fig. 4 is an enlarged sectional diagram corresponding generally to Fig. 3 but illustrating a second practical embodiment of the stretch gasket of the invention. In this embodiment, a fastener in the form of a hook member 30 is provided at each corner of the gasket in place of each button 1 9 of the above-described embodiment. In other respects, however, this gasket is identical to the foregoing and is fitted to a door in a similar manner. The same reference numerals are therefore used for corresponding parts which do not require further description.

Each hook member 30 comprises a retainer 31 located within the central space 29 and a hook 32 extending therefrom and projecting through a hole 33 in the rear wall 22 of the gasket for engagement with a corresponding hole 26 in the door 27 when the gasket is fitted onto the door 27.

A practical embodiment of the hook member 30, as shown in Fig. 5 comprises a bifurcating or two-pronged retainer 31 in the form of a rightangled metal strip and an integral curved hook 32 extending from the retainer 31 in a plane perpendicular thereto. In production of this embodiment of the stretch gasket, each of the two prongs of the retainer 31 is seated in the central space 29 of respective adjoining strip members and the strips are subsequently moulded together so that the hook 32 projects at 33 through the wall 22 at the corner of the gasket. Such a hook member is of course, designed for use in a gasket wherein the strip members are moulded together to form substantially right-angled corners.

A further embodiment of the hook member 30 is shown in Fig. 6. In this case the bifurcating retainer 31 is in the form of a symmetrical angled metal strip provided with apertures 34 for lightness. Such a hook member, is designed for use in a gasket wherein the strip members adjoin at gently curving corners.

The invention is not confined to the precise details of the foregoing examples and variations may be made thereto. Thus, the cross-sections of the strip members and the shapes of the buttons or hook members may vary from what has been illustrated and described. For instance, one or both of the lips 24 may be omitted, as also may the tongue 25, in which case resiliance would be placed upon the resilience of the oval or elliptical strip itself for the door sealing. The head on the button 119 could be round or disc shaped, and the holes 26 can, if desired, be of key-hole-like configuration. Moreover, the fasteners could be in the form of hooks moulded integrally with the gasket. It sould also be appreciated that, although in the embodiments described above the gasket of the invention is fitted to an oven door, it could equally well, and indeed may more commonly be, fitted to the body frame of the oven onto which the door closes. Also, of course, the invention is not limited in application to ovens, and could be applied to a wide variety of structures and door therefor.

Claims

1. A stretch gasket for an oven or other door or for the body frame of an oven or other structure onto which the door closes, comprising a plurality of hollow extruded elastomer strip members of cross-section providing surfaces for sealing against a door surface and the confronting body frame surface, characterised in that the said strip members meet and are integrally moulded at each corner of the gasket and in that a respective fastener projects from the gasket, at each corner thereof, for engagement into a respective hole in the door.

2. A stretch gasket as claimed in claim 1 wherein each fastener is in the form of a button which is integrally moulded with the gasket and is deformable so that it can be snapped into its respective hole.

3. A stretch gasket as claimed in claim 2 wherein the form of each button is such as to provide a relatively narrow stem on which is a frusto-conical head.

4. A stretch gasket is claimed in claim 1 wherein each fastener is in the form of a hook projecting from a corner of the gasket.

5. A stretch gasket as claimed in claim 4 wherein each said hook is integral with a retainer located within the hollow gasket and projects through a hole in the wall of the gasket which is intended to abut the door or the body frame.

6. A stretch gasket as claimed in claim 5 wherein the form of each retainer is bifurcating so as to provide a part or prong extending through each of the two hollow strip members which adjoin at each corner of the gasket.

7. A stretch gasket as claimed in any preceding claim wherein the cross-section of each strip member is of oval configuration providing walls which are approximately parallel to one another and face the door and the oven or other structure, the fasteners projecting from the wall which is intended to be firmly attached to the door or the body frame.

8. A stretch gasket as claimed in claim 7 wherein the cross-section is such as to provide, along each edge of the wall intended to be firmly attached to the door or the body frame, flexible narrow lips for engagement with the abutting surface of the door or the body frame.

9. A stretch gasket as claimed in claim 7 or 8 wherein the cross-section is such as to provide, along one edge of the wall, a wide tongue for engagement with the body frame or door respectively on which the gasket is not to be permanently fitted.

10. A stretch gasket for an oven door or other door hinged to a body or other structure substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 3 or Figs. 4 and 5 or Figs. 4 and 6.