IMPROVED GASKET

Abstract: A seal (25') comprises a gasket (45'), at least a portion of said gasket being elastically deformable, wherein the gasket comprises an opening to allow for the introduction of an insulation material into the gasket, said seal being manufactured by injection moulding.

Description: IMPROVED GASKET The present invention relates to gaskets and in particular, though not exclusively, to a gasket used to provide a hermetic seal between a door or such like and the main body of a refrigeration apparatus such as a refrigeration (fridge) , freezer, fridge-freezer and drinks cooler (chiller) or the like. Hereinafter the term "door" is used to identify a door, hatch, lid cover or other such member which may be openable to permit access to the interior of a refrigeration apparatus . In order to facilitate a hermetic seal between a door and a main body of a refrigeration apparatus there is normally provided an elastically deformable gasket or sealing member. Such gaskets are necessary to seek to maintain a chosen temperature within the refrigeration apparatus and to seek to prevent ingress of undesirable matter such as airborne particles. Conventional gaskets are manufactured from individual lengths of extruded plastics material which are assembled to provide the required gasket size and shape. This often requires the formation of mitred joints. Once assembled the gasket is normally held between a frame and an inner panel of the door. Assembly of the gasket involves the joining of individual extrusions to one another by the use of adhesives or by plastic welding techniques. Such assembly is time and labour intensive and can result in irregularities in the finished gasket, especially at the interface of two or more individual extrusions. Such irregularities may, in use, reduce the efficiency of the gasket or harbour bacteria. In refrigeration equipment one is faced with a temperature differential, ie, in use the inside is colder than the outside. Hence the expansion of inside surfaces is less than that of the outside surfaces. This can cause distortion and/or bending on the lid or door. It is an object of at least some embodiments of the present invention to obviate or mitigate at least some of the aforementioned problems/disadvantages. According to a first aspect of the present invention there is provided a seal comprising a gasket, at least a portion of said gasket being elastically deformable, wherein the gasket comprises an opening to allow for the introduction of an insulation material into the gasket, said seal being manufactured by injection moulding. Preferably the seal is adapted for use in a refrigeration apparatus. Preferably the seal is adapted for attachment to a door lid of a refrigeration apparatus. Preferably the seal may be manufactured as a single piece moulding. Alternatively, the seal may be manufactured from a number of injection moulded strips joined so as to provide the desired seal configuration. Preferably also the seal may be manufactured from a resilient plastics material. The seal may be provided with magnetic means to enhance its sealing properties. The magnetic means may comprise one or more flexible magnetic strips provided on or within the seal. The seal may comprise an outer face, an inner face, an outer leg and an inner leg, and may preferably be substantially "M" shaped in cross-section. One of the legs, preferably the outer leg, may be provided with a lip in order that the seal may be retained upon a door of the apparatus. The lip may comprise a plurality of spaced lip portions (return legs) . The inner leg may also be provided with a lip. According to a second aspect of the present invention there is provided a door incorporating a seal according to the first aspect of the present invention. The door may be fitted to any apparatus to which access to an interior cavity may be required and within which a controllable stable temperature may be maintained. Preferably such apparatus may comprise refrigeration apparatus such as a refrigerator (fridge), freezer, fridge- freezer or drinks cooler (chiller) . According to a third aspect of the present invention there is provided an apparatus within which a controllable stable temperature may be maintained comprising a cabinet, (carton, chest, container, trunk or like body) and at least one openably closable door, wherein the apparatus includes a seal according to the first aspect of the present invention to provide a seal between the door and cabinet. According to a fourth aspect of the present invention there is provided a method of manufacturing at least a portion of a seal comprising the steps of: providing a first mould; providing a second mould; releasably holding said first and second moulds in association with one another; and injecting a plastics material into a space defined between said first and second moulds, so as to form the at least a portion of a seal. Preferably the first and second moulds are male and female moulds, respectively, coacting one with another. Preferably the seal is adapted for use with a refrigeration apparatus. The seal may be manufactured as a single piece moulding or alternatively may be assembled from a plurality of individual seal portions. Embodiments of the present invention will now be described with reference to the accompanying drawings which show: Fig 1 a cross-sectional representation of a door incorporating a prior art seal; Fig 2 a cross-sectional representation of a door incorporating a seal in accordance with an embodiment of the present invention; Fig 3 a plan view of the seal of Fig 2; Fig 4a-4c plan, underside and longitudinal sectional views of a portion of the seal of Fig 2; Fig 5 an enlarged cross-sectional view of the seal of Fig 2 in accordance with an aspect of the present invention; Fig 6 a perspective view from the front and to one side of a chest freezer employing and seal of Fig 2; Fig 7 a side-view of injection moulding apparatus in an open position capable of manufacturing the seal of Fig 2; and Fig 8 a side-view of the injection moulding apparatus of Fig 7 in a closed position. Referring firstly to Fig 1 there is shown a cross- sectional representation of a door 5 comprising part of a refrigeration apparatus. The door 5 comprises a frame member 10, an inner panel 15, an outer panel 20, and a seal 25. In use, the space 30 defined between the inner panel 15 and the frame member 10 is filled with a thermal insulation material such as foamed polyurethane . The seal 25 is provided with a lip 35 which allows the seal to be retained between the frame member 10 and the inner panel 15. In use the seal 25 extends in a continuous "loop" around the perimeter of an inner surface of the door 5 and, once the door 5 is closed, provides a hermetic seal between the door 5 and a facing perimeter surface of a cabinet of the apparatus to which the door 5 is attached. Conventional seals of the type shown in Fig 1 are assembled from a plurality of elements formed by extrusion. Such elements require to be attached to one another by adhesive or plastics welding operations in order to provide a seal of the required size and shape. Referring now to Figs 2 to 5 there is shown a seal 25' in accordance with an embodiment of the present invention. The seal 25' comprises an inner surface 40', an outer surface 45' , an inner leg 50' and an outer leg 55' . The outer leg 55' is further provided with a lip 60' to permit the seal 25' to be retained between the frame 10' and an inner panel 15' of a door 5', while the inner leg 50' is also provided with a lip 65' . The seal 25' is substantially "M" shaped in cross- section with a longitudinally extending central depression 70' on an upper portion of the outer surface 45' , and a central, longitudinally extending spine 75' on an upper portion of the inner surface 40' . The lip 60' further comprises a plurality of spaced lip portions 61' . The "open" design of the seal 25' , as opposed to the closed seals 25 made by extrusion, allows the seal 25' to be manufactured by an injection moulding process wherein injection points 62' are provided along the spine 75'. Furthermore, as shown in Fig 2, the "open" design of the seal allows the inner panel 15' to be formed with a longitudinal channel 80' , for example by a vacuum forming process. The longitudinal channel extends into the seal between the inner and outer legs 50' 55' . This allows for the introduction of solid insulation such as foamed polyurethane to be introduced not only into the space 30' defined between the inner panel 15' and the outer panel 20' but also into the gasket 45' thereby increasing the amount of insulation provided and improving the overall thermal efficiency of the seal or the cabinet. An advantage of the injection moulding process is that complete seals 25', as shown in Fig 3, may be made and this eliminates the need to join together a plurality of seal elements. The spaced lip portions 61' allow for the provision of spaced injection mounting points 62'. Referring to Fig 6 there is shown a chest freezer unit 110' comprising a main body 115' and a hinged lid 120' . A seal 25' according to an aspect of the present invention is provided between the lid 120' and the main body 115' and thus provides a hermetic seal between the lid 120' and main body 115' . Referring now to Figs 7 and 8 there is shown a mould 80' for the production of seals 25' in accordance with the present invention by an injection moulding process. The mould 80' comprises an upper female mould member 85' and a lower male mould member 90' with a cavity 95' corresponding to the shape of the seal 25' defined therebetween. Injection ports 100' are provided in the lower mould member 90' . The seal 25' may be optionally provided with one or more flexible magnetic strips 76'. Such strips may be integrally moulded into the seal 35' and may be provided at or near the outer surface 45' of the seal 25' . The strips may serve to enhance the sealing properties of the seal 25' by magnetically attaching the seal 25' to a surface facing the seal 25' . The embodiments of the present invention hereinbefore described are given by way of example only, and are not meant to limit the scope of the invention in any way. Particularly, it should be appreciated that a beneficial feature of one or more embodiments of the gasket of the present invention is that such a gasket can be made to compensate for temperature differentials between inside and outside a refrigeration apparatus. Prior art gaskets made by extrusion could not be so made.

Claims: CLAIMS 1. A seal comprising a gasket, at least a portion of said gasket being elastically deformable, wherein the gasket comprises an opening to allow for the introduction of an insulation material into the gasket, said seal being manufactured by injection moulding. 2. A seal as claimed in claim 1, wherein the seal is adapted for use in a refrigeration apparatus. 3. A seal as claimed in claim 2, wherein the seal is adapted for attachment to a door/lid of a refrigeration apparatus. 4. A seal as claimed in any preceding claim, wherein the seal is manufactured as a single piece moulding. 5. A seal as claimed in any of the claims 1 to 3, wherein the seal is manufactured from a number of injection moulded strips joined so as to provide the desired seal configuration. 6. A seal as claimed in any preceding claim, wherein the seal is manufactured from a resilient plastics material. 7. A seal as claimed in any preceding claim, wherein the seal is provided with magnetic means to enhance its sealing properties. 8. A seal as claimed in claim 7, wherein the magnetic means comprises one or more flexible magnetic strips provided on or within the seal. 9. A seal as claimed in any preceding claim, where in the seal comprises an outer face, an inner face, an outer leg and an inner leg. 10. A seal as claimed in any preceding claim, wherein the seal is substantially "M" shaped in cross-section. 11. A seal as claimed in claim 9 when dependent on claim 2, wherein one of the legs is provided with a lip in order that the seal may be retained upon a door of the apparatus. 12. A seal as claimed in claim 11, wherein said one of the legs is the outer leg. 13. A seal as claimed in claim 11, wherein the lip comprises a plurality of lip portions (return legs) . 14. A seal as claimed in any of the claims 11 to 13, wherein the inner leg is also provided with a lip. 15. A door incorporating a seal according to any of the claims 1 to 14. 16. A door as claimed in claim 15, wherein, the door is fitted to any apparatus having an interior cavity to which access to an interior may be required, in use, and within which a controllable stable temperature may be maintained. 17. A door as claimed in claim 16, wherein the apparatus comprises refrigeration apparatus such as a refrigerator (fridge), freezer, fridge-freezer or drinks cooler (chiller) . 18. An apparatus within which a controllable stable temperature may be maintained comprising a cabinet, (carton, chest, container, trunk or like body) and at least one openably closable door/lid, wherein the apparatus includes a seal according to any one of claims 1 to 14 to provide a seal between the door/lid and cabinet. 19. A method of manufacturing at least a portion of a seal comprising the steps of: providing a first mould; Providing a second mould; releasably holding said first and second moulds in association with one another; and injecting a plastics material into a space defined between said first and second moulds, so as to form the at least a portion of a seal. 20. A method as claimed in claim 19, wherein the first and second moulds are male and female moulds, respectively, capable of coacting one with another. 21. A method as claimed in claim 20 or 21, wherein the seal is adapted for use with a refrigeration apparatus. 22. A method as claimed in any of claims 19 to 21, wherein the seal is manufactured as a single piece moulding or alternatively is assembled from a plurality of individual seal portions.

Inventors: GRANT ALEXANDER, GRANT, ALEXANDER
Applicants: GRANT ALEXANDER, NORFROST LTD, GRANT, ALEXANDER, NORFROST LIMITED
Application year: 1997
Main classification: F25D23
IPC codes: B29C45, E05C19, F25D23