SEALING GASKET

Abstract: A sealing gasket (30) for sealing a joint between two substantially perpendicular members. The gasket has an anchor (31) for insertion in the joint between the two members and two resilient portions (40, 50) of bearing on the surfaces of each of the members to provide a sealed joint. The sealing gasket has particular application in the sealing of a wall to a roof of a refrigerated freight container.

Description: SEALING GASKET This invention relates to a sealing gasket. The invention has particular, although not exclusive, application in sealing a junction between an inner skin of a double-skinned wall of a refrigerated freight container and an inner skin of a double-skinned roof of the container. Known insulated freight containers are produced from panels of steel/ foam/ stainless steel sandwiches or aluminium/foam/stainless steel sandwiches, having foam cores in both cases. These sandwich panels are produced as individual items in a foam press and then joined together to form a container in an assembly jig. Once the panels have been assembled, the joints between the panels are sealed and foam is injected into the voids between the foam cores of the sandwich panels, for example, a wall and a roof. In this way, the insulated container is provided with insulation in the walls, floor and roof of the container. The joints between the panels need to be as secure and watertight as possible to prevent the ingress of water and moisture, to retain the insulating properties of the foam, and because water causes the sandwich panels to delaminate. In the prior art, most attention has been given to the bottom joint between the side panels and the floor, where a combination of manufacturablility and watertightness are essential. The top joint, on the other hand, generally needs to be simple, watertight and reliable. Manufacturing tolerances of the sandwich panels are such, that is impossible to build a joining member into the panels themselves, and therefore, the joining member is applied over the ends of the stainless steel inner skins. A second fundamental requirement for the joints is that they should be reasonably flexible. Insulated containers flex as they are loaded and transported, which places a strain on the joint between the side panels and the roof panel. Seals in the form of cover panels applied over the inner liner ends are liable to become detached unless some form of mechanical fixture is used to hold them in place. Cover panels are used in the prior art to cover the joint in combination with a sealant used to keep the joint watertight. Although, in principle, adhesives could be used to replace the sealant, manufacturers and users at present are not content to rely on a bonded joint. It is an object of this invention to provide a sealing gasket which substantially mitigates the difficulties found in the prior art. According to a first aspect of the invention there is provided a sealing gasket for sealing a joint between a first member and a second member joined perpendicularly to the first member, the gasket comprising an anchor means for insertion between the joint between the first member and the second member: a first resilient portion joined to the anchor means and adapted to bear on the first member and a second resilient portion joined to the anchor means adapted to bear on the second member, wherein, in a free state, the first resilient portion diverges from the second resilient portion, subtending an obtuse angle therebetween. According to a second aspect of the invention there is provided a sealing gasket having a longitudinal axis, the gasket being for sealing a junction between an inner skin of a double-skinned wall of a refrigerated freight container and an inner skin of a double-skinned roof of the container, the gasket comprising anchor means for insertion within one of the wall and the roof for anchoring the gasket to one of the wall and roof, a resilient first portion joined to the anchor means for bearing against an internal surface of the inner skin of the wall and a resilient second portion joined to the anchor means for bearing against an internal surface of the inner skin of the roof to form a flexible watertight seal between the inner skin of the wall and the inner skin of the roof. According to a third aspect of the invention there is provided a method of sealing an inner skin of a double-skinned wall of a freight container to an inner skin of a double-skinned roof of the container, the method comprising the steps of: a) providing a sealing gasket having anchor means, a resilient first portion and a resilient second portion; b) forming the double-skinned wall such that the anchor means is anchored within the wall at an end of the wall to be joined to the roof, with the first portion bearing resiliently on a surface of the wall; c) fixing the double-skinned roof to the end of the wall so that the surface of the wall on which the first portion bears forms an inner surface of the wall of a freight container and such that the second portion resiliently bears on an inner surface of the roof of the container. According to a fourth aspect of the invention, there is provided a freight container including a seal according to the first or second aspects of the invention. The sealing gasket of the present invention provides a flexible water-tight joint, without the need for sealant or mechanical fastenings. The gasket is applied to a side panel prior to assembly and is sufficiently flexible to take up tolerances encountered in the manufacture of insulated containers. The gasket is also sufficiently flexible to maintain a seal between a wall and roof as a container flexes in use. The invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a cross-section of a seal of the prior art; Figure 2 shows a cross-section of another seal of the prior art; Figure 3 shows a transverse cross-section of a first embodiment of a sealing gasket according to the invention in a free state; Figure 4 shows the transverse section of figure 3 and shows in outline, the shape taken up by the gasket in use; Figure 5 shows the gasket of figure 3 installed on a side wall of a container; Figure 6 shows an enlarged partial view of the upper end of the wall of figure 5 with the gasket installed; Figure 7 shows a sectional view of the wall and gasket of figure 6 together with an end of a roof panel joined to the wall section; and Figure 8 shows a perspective view of a second embodiment of a gasket in accordance with the invention in use at a joint between a wall panel and a roof panel. In the figures like reference numerals denote like parts. As shown in figures 1 and 2, known insulated freight containers are produced from panels of steel/foam/stainless steel sandwiches or aluminium/foam/stainless steel sandwiches 17, 18;27,28, having foam cores 13;23 respectively. These sandwich panels are produced as individual items in a foam press and then joined together to form a container in an assembly jig. Once the panels have been assembled, the joints between the panels 17,18;27,28 are sealed and foam is injected into the voids between the foam cores 13;23 of the sandwich panels, for example, a wall and a roof. In this way, the insulated container is provided with insulation in the walls, floor and roof of the container. A known seal 10 for sealing the roof panel 17 to the wall panel 18 is formed by a moulding which snaps over the steel ends of the internal lining of a wall or, as illustrated in figure 1 , relies on an outer moulding 1 1 which is riveted to an inner lining 15 of the side wall 18 and an inner lining 16 of the roof panel 17 to which a cover 12 is clipped. A further seal 20 of the prior art is shown in figure 2, which includes a cover 21 held in place over a join between a roof panel 27 and a wall panel 28 by fixing the cover 21 to an inner lining 25 of the wall panel 28 and an inner lining 26 of the roof panel 27 with fixings 22. A transverse cross-section of a sealing gasket 30 of the present invention is shown in figures 3 to 7. The transverse cross-section shown in figure 3 shows the shape taken by the gasket in free space. The gasket has an anchor 31, and a first portion 40 and a second portion 50 joined by a junction 60 to the anchor 31. The transverse cross-section of the anchor is generally L-shaped, having a horizontal portion 32 in use and a downwardly dependent portion 33 in use located at an end of die horizontal portion 32 remote from the junction 60 with the first portion 40 and the second portion 50. The first portion 40 and the second portion 50 each have an arcuate transverse cross-section tapering towards ends 41,51 respectively remote from the joint junction 60 with the anchor 31. The second portion 50 in the free-state is upwardly (as shown in figures 3 and 4) concave so that a concave surface 52 is presented to an internal surface 71 of a roof panel 70 in use and the first portion is concave towards the anchor so as to present a concave surface 42 towards a surface 81 of a wall panel 80 in use, as shown in figure 7. The second portion 50 and first portion 40 are therefore arcuately divergent in a free state. A longitudinal stress-relieving groove 61 is provided at a junction of the first portion 40 and the second portion 50. In the embodiment shown in figures 3 to 7, the arcuate portions 40,50 are of substantially the same length as each other, whereas in the embodiment shown in figure 8, the second portion 350 is longer and has a smaller cross-sectional area than the first portion 340. As shown in figure 4, in use, the first portion 40 is forced by the wall into a position 40' in which a wall abutting surface 42' of the first portion 40' is perpendicular to the horizontal portion 32 of the anchor 31 and the second portion 50 is forced into a position 50' by the roof panel 70 in which a roof abutting surface 52' of the second portion 50' is substantially co-planar with an upper surface 34 of the horizontal portion 32 of the anchor 31. As shown in figures 5, 6 and 7, the gasket is applied to a side panel 80 prior to assembly of the container wall to the roof 70. The upper end of the wall 80 is provided with a recess 82 in the inner skin 85 and partially into the foam core 83. The downwardly dependent portion 33 of the anchor 31 is embedded in the foam core 83 of the side wall sandwich panel 80 and the wall abutting surface 42 of the first portion 40 abuts a surface 81 of the inner skin 85 of the wall panel 80 with an upper end 84 of the wall inner skin 85 located in a vertex 62 (see figure 4) between the first portion 40 and the horizontal portion 32 of the anchor 31 so that a lower surface 35 of the anchor 31 abuts a lower surface of the recess 82 formed in the wall 80. As shown in figure 7, in assembling the roof 70 to the wall 80, the end of the foam portion 72 and the inner skin of the roof are located in the recess 82 in the wall 80 so that an inner surface 71 of the inner skin 76 of the roof 70 bears on the upper surface 34 of the horizontal portion 32 of the anchor 31. The roof abutting surface 52 of the second portion 50 bears on the inner surface 71 of the roof 70. In doing so, the horizontal portion 32 of the anchor 31 is stretched so that a gap 63 is opened between the vertex 62 between the first portion 40 and the anchor 32 and the wall 80 so that the first portion 40 is held in tension, both by its natural curvature and by tension in the anchor 31, against the wall 80 and similarly the second portion 50 is held in tension against the roof 70 both by the tension within the anchor 31 and by being forced against its natural curvature.

Claims: CLAIMS: 1. A sealing gasket for sealing a joint between a first member and a second member joined substantially perpendicularly to the first member, the gasket comprising an anchor means for insertion in the joint between the first member and the second member: a first resilient portion joined to the anchor means and adapted to bear on the first member and a second resilient portion joined to the anchor means adapted to bear on the second member wherein in a free state, the first resilient portion diverges from the second resilient portion, subtending an obtuse angle therebetween. 2. A sealing gasket as claimed in claim 1 , wherein a portion of the anchor means is resilient such that the resilient portion of the anchor means is held in tension in use. 3. A sealing gasket as in any of the preceding claims wherein, the first portion and second portion are arcuately divergent. 4. A sealing gasket having a longitudinal axis, the gasket being for sealing a junction between an inner skin of a double-skinned wall of a refrigerated freight container and an inner skin of a double-skinned roof of the container, the gasket comprising anchor means for insertion within one of the wall and the roof for anchoring the gasket to one of the wall and the roof, a resilient first portion joined to the anchor means for bearing against an internal surface of the inner skin of the wall and a resilient second portion joined to the anchor means for bearing against an internal surface of the inner skin of the roof to form a flexible watertight seal between the inner skin of the wall and the inner skin of the roof. 5. A sealing gasket as claimed in claim 4 wherein, in a free state, the first portion and second portion are divergent, subtending an obtuse angle therebetween. 6. A sealing gasket as claimed in claims 4 or 5, wherein transverse to the longitudinal axis, the first portion has an arcuate cross-section, being concave towards the anchor means in the free state. 7. A sealing gasket as claimed in any of claims 4 to 6, wherein the first portion tapers from a junction with the anchor means and the second portion towards an opposed remote end of the first portion. 8. A sealing gasket as claimed in any of claims 4 to 7, wherein the second portion tapers from a junction with the first portion and the anchor means towards an opposed remote end of the second portion. 9. A sealing gasket as claimed in any of claims 4 to 8, wherein a longitudinal portion of the anchor is resilient so that in use, the longitudinal portion is in tension. 10. A method of sealing an inner skin of a double-skinned wall of a freight container to an inner skin of a double-skinned roof of the container, the method comprising the steps of: a) providing a sealing gasket having anchor means, a resilient first portion and a resilient second portion; b) forming the double-skinned wall such that the anchor means is anchored within the wall at an end of the wall to be joined to the roof, with the first portion bearing resiliently on a surface of the wall; c) fixing the double-skinned roof to the end of the wall so that the surface of the wall on which the first portion bears forms an inner surface of the wall of a freight container and such that the second portion resiliently bears on an inner surface of the roof of the container. 11. A freight container including a seal as claimed in any of claims 1 to 9. AMENDED CLAIMS [received by the International Bureau on 26 May 2000 (26.05.00); original claim 1 amended; remaining claims unchanged (1 page)] 1. A sealing gasket for sealing a joint between a first member and a second member joined substantially perpendicularly to the first member, the gasket comprising an anchor means for insertion within one of the first member and the second member for anchoring the gasket to one of the first member and the second member; a first resilient portion joined to the anchor means and adapted to bear on the first member and a second resilient portion joined to the anchor means adapted to bear on the second member wherein in a free state, the first resilient portion diverges from the second resilient portion, subtending an obtuse angle therebetween. 2. A sealing gasket as claimed in claim 1 , wherein a portion of the anchor means is resilient such that the resilient portion of the anchor means is held in tension in use. 3. A sealing gasket as in any of the preceding claims wherein, the first portion and second portion are arcuately divergent. 4. A sealing gasket having a longitudinal axis, the gasket being for sealing a junction between an inner skin of a double-skinned wall of a refrigerated freight container and an inner skin of a double-skinned roof of the container, the gasket comprising anchor means for insertion within one of the wall and the roof for anchoring the gasket to one of the wall and the roof, a resilient first portion

Inventors: HATTON JOHN, HATTON, JOHN
Applicants: HATTON JOHN, SEA CONTAINERS LTD, HATTON, JOHN
Application year: 1999
Main classification: F16J15
IPC codes: F16J15, F25D23