GB2372762A

GB2372762A - Sealed gutter joint

Info

Publication number: GB2372762A
Application number: GB0201731A
Authority: GB
Inventors: Geoffrey Quinnell
Original assignee: Marley Extrusions Ltd
Current assignee: DHM Plastics Ltd
Priority date: 2001-01-25
Filing date: 2002-01-25
Publication date: 2002-09-04
Anticipated expiration: 2022-01-25
Also published as: GB0201731D0; GB2372762B; GB0102007D0

Abstract

A gutter jointing system comprises a union member 2 and a length of gutter (Fig 4a, 26), said union member being provided with a resilient seal 12 circumferentially on its outer surface 8 for making a watertight seal with the gutter member 26, as shown in Fig 6. Fig 3 shows the profile of the seal 12 with a generally flat central portion 22 with wings 24 at either edge, extending at approximately 45 degrees. Upon assembling the union member with the gutter member, the wings 24 of the seal are bent and somewhat flattened outwards, placing at least a portion of the seal in tension, creating a sealing effect between the two components to prevent liquid leaking from the joint.

Description

Sealed Joints This invention relates to joints between pipes and especially roof gutters and the like, which are required to be sealed to prevent leakage of water or other liquid being carried thereby.

Gutters are typically produced in standard lengths which are joined together to form a continuous run of the desired length. Other elements such as downpipe junctions, endstops etc. which are familiar to those skilled in the art are also fitted to gutters. All of these joints must be reliably sealed to prevent leaks and the seals must maintain their integrity for a reasonable lifetime.

Conventionally two extruded lengths of gutter are joined together using a union member which fits over the two adjacent ends to be joined and is clamped tightly to the outer surface of the gutters in order to clamp seals between the inner surface of the union and the outer surfaces of each length of gutter. Each seal is typically received in an internal groove in the union member and may be attached thereto in a variety of ways such as adhesive, dovetail mounting etc.

More recently it has been proposed in GB-A-2323866 and WO 00/20704 to use a spigot fitting to join gutter elements together and to provide a seal on the spigot to seal against the internal surface of the gutter being joined. Clearly in such arrangements a loose seal would be inappropriate and a deep groove of the sort used in external union members would give rise to an undesirable restriction on the inside of the gutter. Also adhesives tend to dry out over time and thus become ineffective.

One way to get round the problems mentioned above would be to bond the seal onto the spigot by co-moulding. However it has been found that seal

materials possessing the properties to bond sufficiently strongly to PVC, from which plastics gutter systems are usually made, also exhibit a high compression set. This is the name given to the tendency of resilient materials to lose their resilience when placed under compression for a prolonged period. In the context of gutters this is clearly undesirable since it means that inevitable small movements of the gutter-e. g. due to thermal expansion and contraction-are likely to result in the seal being breached.

The present invention aims to provide an improved arrangement and when viewed from a first aspect provides a gutter jointing system comprising first and second gutter elements to be joined together, said first gutter element being provided with a resilient seal for sealingly engaging the second gutter element, wherein said seal is so shaped that, upon assembly together of the two elements, at least a portion of the seal is placed in tension.

Thus it will be seen that in accordance with the invention, in contrast to all known seals which function by compression, a seal is provided which seals under tension. The invention stems from a realisation that whilst the sealing materials mentioned above with good bonding characteristics have poor compression properties, they are significantly more durable under tension. Thus in accordance with preferred embodiments, a suitable seal material may be chosen for its reliable bonding properties without the quality of the seal being hampered by a poor performance under compression.

It will be appreciated that no modification is necessary to the gutter element without the seal and therefore that the invention extends to the gutter element with the seal, alone. When viewed from a second aspect therefore, the present invention provides a gutter element for engaging with another gutter element and comprising a resilient seal for sealingly engaging

said other gutter element, wherein said seal is so shaped that upon assembly of the gutter element to the other gutter element, at least a portion of said seal is placed in tension.

The required tension in the seal is preferably brought about by bending a portion thereof from its natural position. Many different shapes for the seal may be envisaged which will result in a portion thereof being bent out of position when the gutter is assembled. Preferably the seal comprises a base portion attached to the gutter element and a portion protruding outwardly therefrom such that the protruding portion is made to bend by contact with the sealing surface of the cooperating gutter element. Such bending creates the desired tension in the seal material and biases the protruding portion against the cooperating gutter surface to form a seal therebetween as it tries to return to its natural position.

In a particularly preferred embodiment the protruding portion is in the form of a wing which extends at about 4s'to the longitudinal axis of the gutter element to which the seal is attached. This ensures that the wing is the first part of the seal to contact the opposing gutter surface when the gutter joint is being assembled, whilst allowing space for the wing to be bent towards the gutter element to which the seal is attached as assembly of the joint is completed.

Although a single wing may be provided, it is preferred to provide at least two. This enables the two wings to balance one another which can help to prevent unwanted pivoting of the joint under load. Most preferably the two wings extend in opposite longitudinal directions. This helps to ensure that if any relative longitudinal movement of the two joined gutter elements, e. g. due to thermal expansion/contraction, reduces the degree of flexing of one of the wings, the other will still be able to maintain an effective seal. Of course,

more than two wings or other protrusions may be provided.

The seal may be attached to the gutter element in any suitable manner. Preferably it is moulded onto a surface of the gutter element. This gives a strong, durable attachment. Furthermore, materials are available which may be co-moulded with PVC, from which it is preferred that the gutter element is made, and which make suitable seals in accordance with the invention.

The seal should be made from, or include, a suitable resilient material, i. e. one which exhibits suitable properties in tension resulting from bending.

In preferred embodiments of the invention the seal is made from a synthetic thermoplastic polymer. Preferably a partially cross-linked, chlorinated olefin interpolymer alloy is used. An example of a suitable such material is Alcryn (registered trade mark) Melt-Processible Rubber available from Advanced Polymer

Alloys of Wilmington, Delaware, USA. In another

exemplary embodiment, the seal is made from Vaycron (KTM)

VA2010 available from Hydro Polymers, Newton Aycliffe, Co. Durham and having a tensile strength of 1. 1 x 107 Pascals at 500 mm/min and other properties similar to EN 681/2. It has also been found that nitryl rubbers may be used with satisfactory results.

The gutter element in accordance with the invention could be an otherwise conventional union member, length of gutter, downpipe junction, endstop etc. Preferably gutter element comprises a spigot on which the seal is provided. This could a gutter length, as disclosed in GB-A-2323826 or a separate union member as disclosed in WO 00/20704, or indeed any other gutter element. As was explained previously, it is particularly beneficial to be able to mould a seal onto the spigot of a gutter element, since other fixing techniques are less satisfactory. In accordance with the invention this may

be done without prejudicing the ability of the seal material to form a reliable seal.

It will be appreciated by those skilled in the art that whilst the present invention has been discussed in terms of joints between gutter elements, in fact the advantage of the invention are applicable more widely than just to gutters and the principles of the invention may be usefully employed in any application where two pipes or conduits, especially plastics, e. g. PVC ones, need to be joined together. Thus when viewed from a further broad aspect the present invention provides an element of a pipe or conduit for conveying a fluid and a seal provided at one end of said element for sealing against another element when coupled thereto, wherein said seal is so shaped that upon assembly of the elements together at least a portion of the seal is placed in tension.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a close-up perspective view of one half of a double spigot gutter union member in accordance with the present invention; Figs. 2a to 2c are respectively side, plan and end elevations of a union member very similar to that in Fig. 1 prior to moulding the seal on; Fig. 3 is an enlarged cross-sectional view of the seal; Figs. 4a and 4b are respectively end and side elevations of a length of gutter to which the union member of Fig. 1 is fixed; Fig. 5 is a perspective view of the seal member; and Fig. 6 is an enlarged cut-away view of the assembled joint.

Turning firstly to Figure 1, an enlarged view of a double spigot gutter union member 2 may be seen. A

smaller side view of a very similar union member (without the seal) may be seen in Figure 2a. The union member 2 generally comprises a pair of spigots 4 separated by a stop ridge 6. The spigots 4 are designed such that the basic cross-section of the outer surface 8 thereof substantially matches the inner cross-section of a length of gutter. Further details of this arrangement are given in WO 00/20704. It may be seen that the outer surface 8 has a circumferentially extending recessed portion 10 and that a seal member 12 is attached thereto. This will be explained in more detail later.

Four corner tabs 14 project upwardly beyond the top edge 16 of the spigot 4 at each corner of the union member 2 (only one of which may be seen in Fig. 1).

MTMÝ The union member 2 is made by uPVC and the seal jy member 12 is made from VAYCRON^V 2010 which is available member 12 is made from VAYCRONAVA2010 which is available from Hydro Polymers, Newton Aycliffe, Co. Durham.

Figures 2a to 2c show respectively side, plan and end views of a gutter union identical to that in Fig 1 except for a slight difference in the positioning of the upwardly projecting tabs 14. Regarding these Figures, the uPVC union member 2 is first moulded without the seal 12. As well as the features of the union member 2 mentioned in relation to Figure 1, it may further be seen from Figure 2a that a pair of parallel ribs 18 extending circumferentially around the spigot 4 are integrally moulded in the recessed portion 10 of the outer surface 8. The seal 12 is formed by moulding it onto the spigot 4 over the ribs 18. As may be seen from the isolated view of the seal in Figure 5, by moulding the seal 12 over the circumferential ribs 18 on the spigot, two corresponding parallel grooves 20 are formed in the seal material. The ribs 18 thus serve to increase the surface area over which the seal 12 is in contact with the surface 8 of the spigot, thus increasing the strength of the bond between the seal 12 and the spigot 4.

It will be seen from Figures 3 and 5 that the seal 12 has a generally flat portion 22 in the centre part of its profile and wings 24 at either edge extending outwardly at approximately 450. The function of these wings is described hereinbelow.

It may further be seen, from Figure 2c, that three longitudinal ribs 19 are provided in the lower region of the spigot 4.

Turning to Figures 4a and 4b, there may be seen end and side elevations respectively of a length of extruded uPVC gutter 26 which the gutter union member is designed to join to a similar length of gutter. With reference to Figure 4a the gutter 26 has a generally U-shaped profile, the inner surface 27 of which has a cross-section that substantially matches the cross-section of the outer surface 8 of the spigot 4.

At its top edges the gutter has elongate hook portions 28 which are shaped to fit over the top edges 16 of the spigot 4. The edges of the hooks 28 are formed as inclined camming surfaces 30 to facilitate clipping the gutter length 26 over the spigot 4 of the union member 2. An elbow 34 is formed at the proximal edge of each to secure the clip in place.

Longitudinal slots 32 are formed in the upper edges of the gutter (see Figure 4b) to receive the protruding tabs 14 although the slots 32 are longer than the width of the tabs 14.

The fitting of the union member 2 to the length of gutter 26 and the function of the seal 12 will now be described with reference to Figure 6 in addition to the previously described Figures. In order to fit the union member 2 to the length of gutter 26, the hook 28 on one side of the gutter 26 is hooked over the corresponding edge 16 of the spigot 4 such that the corresponding protruding tab 14 is located in the notch 32 in the top edge of the gutter. The gutter 26 is then pulled around the opposite top edge 16 of the spigot 4. As further

pressure is applied, the inclined camming surface 30 will move over the top edge 16 of the spigot 4 and thus clip into place with the top edge hook 28 of the gutter hooked over the top edge 16 of the spigot. The elbows 34 ensure that the gutter 26 remains tightly clipped over the spigot 4.

Considering Figure 6, it may be seen that when the inner surface 27 of the gutter 26 is pressed against the outer surface 8 of the spigot 4 by the above-mentioned clips, the two wings 24 of the seal 12 are bent and somewhat flattened. The reaction of the resilient seal material gives rise to the sealing force between the seal and the inner surface 27 of the gutter. By stretching rather than compressing the material of the seal 12, potential problems associated with compression set are avoided.

By virtue of the longitudinal ribs 19 on the lower portion of the spigot 4, the wings 24 of the seal in this region are prevented from being over-stretched since the ribs 19 prevent the spigot 4 and the gutter 26 from being pressed completely together in this region.

This is important since, with the clip arrangement for retaining the gutter onto the spigot for the union member, the lower portions thereof are subjected to the greatest pressure. The ribs 19 are preferable to making the wall of the spigot 4 thicker, since this would make it more difficult to clip the gutter over the spigot as described above.

Inevitably, thermal expansion and contraction will occur in the length of gutter 26 and, to a lesser extent, the union member 2. When this occurs, relative longitudinal movement is allowed by the projecting tab 14 moving within the notches 32 in the upper edges of the gutter. Since the two wings 24 of the seal project in opposite longitudinal directions, longitudinal movement in either direction which might adversely affect the seal between one of the wings 24 and the

outer surface of the gutter 26, will act in the opposite direction on the other wing 24.

By spreading the area over which the seal 12 contacts the gutter 26, a degree of balancing between the two wings 24 is achieved which makes pivoting of the gutter length 26 relative to the union member 2 less likely. Furthermore, any such pivoting which does occur which might reduce the sealing force of one of the wings 24, will increase it on the other.

It will be appreciated by those skilled in the art that the foregoing is a description of just one possible embodiment of the invention applied to gutters and that many different applications of the invention in other fields are also possible. For example, the sealing arrangement in accordance with the invention may be used to seal any sort of closed circumference pipe or conduit which needs to be joined together and sealed.

Claims

Claims :

1. A gutter jointing system comprising first and second gutter elements to be joined together, said first gutter element being provided with a resilient seal for sealingly engaging the second gutter element, wherein said seal is so shaped that, upon assembly together of the two elements, at least a portion of the seal is placed in tension.

2. A gutter element for engaging with another gutter element and comprising a resilient seal for sealingly engaging said other gutter element, wherein said seal is so shaped that upon assembly of the gutter element to the other gutter element, at least a portion of said seal is placed in tension.

3. A gutter element or jointing system as claimed in claim 1 or 2 wherein the required tension in the seal is brought about by bending a portion thereof from its natural position.

4. A gutter element or jointing system as claimed in claim 3 wherein said seal comprises a base portion attached to the gutter element and a portion protruding outwardly therefrom such that the protruding portion is made to bend by contact with the sealing surface of the cooperating gutter element.

5. A gutter element or jointing system as claimed in claim 5 wherein the protruding portion is in the form of a wing which extends at about 450 to the longitudinal axis of the gutter element to which the seal is attached.

6. A gutter element or jointing system as claimed in claim 5 wherein the seal comprises at least two wings.

7. A gutter element or jointing system as claimed in claim 6 wherein both or two of said wings extend in opposite longitudinal directions.

8. A gutter element or jointing system as claimed in any preceding claim wherein the seal is attached to the gutter element by being moulded onto a surface of the gutter element.

9. A gutter element or jointing system as claimed in any preceding claim wherein the gutter element is made from or contains PVC or the like.

10. A gutter element or jointing system as claimed in any preceding claim wherein said seal is made from a synthetic thermoplastic polymer.

11. A gutter element or jointing system as claimed in claim 10 wherein said synthetic thermoplastic polymer comprises a partially cross-linked, chlorinated olefin interpolymer alloy.

12. A gutter element as claimed in any of claims 2 to 11 comprising a spigot on which the seal is provided.

12. An element of a pipe or conduit for conveying a fluid and a seal provided at one end of said element for sealing against another element when coupled thereto, wherein said seal is so shaped that upon assembly of the elements together at least a portion of the seal is placed in tension.

13. A gutter element or jointing system substantially as hereinbefore described with reference to the accompanying drawings.