GB2414031A

GB2414031A - Drainage channel element

Info

Publication number: GB2414031A
Application number: GB0410475A
Authority: GB
Inventors: Ben Hardman
Original assignee: Hepworth Building Products Ltd
Current assignee: Hepworth Building Products Ltd
Priority date: 2004-05-11
Filing date: 2004-05-11
Publication date: 2005-11-16
Anticipated expiration: 2024-05-11
Also published as: GB0410475D0; GB2414031B

Abstract

The drainage channel element 1 comprises a body 8 with a first end region 3 and a second, opposite end region 5, each of which comprise a pair of opposed side walls 2 interconnected by a base 4. The first end region is provided with a generally radially outwardly directed flange 7 or recess and the second end region with a seat that comprises a generally radially inwardly directed flange or recess 9 adapted to engage with the outwardly directed flange of an adjacent drainage channel element so as to constrain relative axial movement between the two elements yet allow rotation of one element relative to the other about an axis which extends transversely to at least one of the channel elements when the two are connected. The inwardly directed flange/recess may extend around the entire periphery of the respective end region or may only extend down the upper, in use, portions of the end regions. An axially extending tongue may be provided that extends from the first end region which is designed to be received in an axially extending slot 13 in the second end region of an adjacent element. A fulcrum point in the form of a projection may be provided on one of the flanges. Also claimed is a drainage channel system and a method of connecting drainage channel elements.

Description

241403 1 )

DRAINAGE CHANNEL SYSTEM

The present invention relates to a drainage channel system. More particularly, the invention relates to a drainage channel system that allows a drainage channel assembly to be constructed from a plurality of drainage channel elements.

Drainage channels of the type referred to herein are typically located in the ground as gutters for rainwater or any other liquid that needs to be drained away.

EP 0 542 701 describes a known modular drainage channel system, for use as a gutter assembly. The described assembly incorporates a plurality of drainage channel sections, which are fitted together to form a length of "uttering. The drainage channel sections each comprise a first end region provided with a radially outwardly directed flange and a second end region provided with a radially inwardly directed channel. In order to connect sections together, a flange from one section is fitted into a channel in an adjacent section. The accommodation of the flanges within the channels provides a relatively secure resistance against axial displacement between adjacent sections.

Such known drainage channel systems suffer from the disadvantage that they do not readily accommodate ground irregularities during installation or ground displacement once in use. The present invention therefore sets out to overcome these problems by providing a drainage channel system which is more adaptable to local ground conditions at all times.

According to a first aspect of the present invention there is provided a drainage channel element comprising a body having a first end region and a second, opposite end region, each said end region comprising a pair of opposed side walls interconnected by a base, wherein the said first end region is further provided with a generally radially outwardly directed flange or recess and the said second end region is further provided with a seat, the said seat comprising a generally radially inwardly directed flange or recess which is adapted to engage with a said flange or recess provided in the first end region of another drainage channel element in such a manner as to constrain relative axial displacement between the two elements, yet allow rotation of one element relative to the other about an axis which extends transversely to at least one of the said element and the said another element when the two are so connected.

A drainage channel assembly formed from such elements is able to accommodate both irregularities in the ground in which it is being installed and also movement in the ground after installation. This is as a consequence of the relative rotation permitted by the connection between adjacent drainage channel elements.

The said first end region preferably comprises a said generally radially outwardly directed flange and the said second end region preferably comprises a said generally radially inwardly directed recess adapted to receive a said radially outwardly directed flange from another drainage channel element.

It is further preferred that the said second end region comprises a pair of opposed said radially inwardly directed recesses, each said recess being located so as to be in an upper region of a respective one of the side walls of the second end region when in use.

Each said recess may be defined on an axially inner side by an axially outwardly facing shoulder and an axially outer side by a radially inwardly directed projection.

The said axially outwardly facing shoulder defining each recess may be part of a single axially outwardly facing shoulder extending around substantially the entire periphery of the second end region.

Preferably the said radially inwardly directed projections are each configured so as to extend downwardly from an upper portion of a respective one of the said side walls of the said second end region and terminate above the said base of the said second end region when in use. i

In an alternative embodiment, the said second end region may comprise a said generally radially inwardly directed flange and the said first end region may comprise a said generally radially outwardly directed recess adapted to receive a said radially inwardly directed flange from another drainage channel element. In such a case the said first end region may comprise a pair of opposed said radially outwardly directed recesses, each said recess being located so as to be in an upper region of a respective one of the said side walls of the said first end region when in use.

Each said recess may be defined on an axially inner side by an axially outwardly facing shoulder and an axially outer side by a radially outwardly directed projection. The said axially outwardly facing shoulder defining each recess may be part of a single axially outwardly facing shoulder extending around substantially the entire periphery of the first end region.

The said radially outwardly directed flange may extend around substantially the entire periphery of the said first end region.

It is particularly preferred that the said seat comprises a formation in a part thereof that is defined by the said base of the second end region, the said formation being adapted to co-operate with a formation provided in a said first end region of another drainage channel element in such a manner as to assist relative lateral andlor circumferential alignment between the two elements when connected together, yet allow the said rotation of one element relative to the other about the said transverse axis. The said seat may then be provided with an axially extending slot for receiving an axially extending tongue provided in a first end region of another drainage channel element.

It is also particularly preferred that the said base of the first end region comprises a formation which is adapted to co-operate with a formation provided in a said seat of another drainage channel element in such a manner as to assist relative lateral and/or circumferential alignment between the two drainage channel elements when connected together, yet allow the said rotation of one element relative to the other about the said transverse axis.

The said first end region may be provided with an axially extending, radially outwardly projecting tongue for entering an axially extending slot provided in a said seat of another drainage channel element.

Either the said first end region or the said second end region may comprise a fulcrum formation for defining the said transverse axis. The said fulcrum formation may take the form of a projection. The said projection defining the fulcrum formation may be situated on an axially facing end surface of the said drainage channel element that is located in the said first end region.

The said element may be a drainage channel section or a sump unit.

According to a second aspect of the invention there is provided a drainage channel system comprising a first drainage channel element and a second drainage channel element, the said first element comprising a body having a first end region and the said second element comprising a body having a second end region, each said end region comprising a pair of opposed side walls interconnected by a base; wherein the said first end region is further provided with a generally radially outwardly directed flange or recess and the said second end region is further provided with a seat, the said seat comprising a generally radially inwardly directed flange or recess which is adapted to engage with the said flange or recess provided in the first end region in such a manner as to constrain relative axial displacement between the two elements, yet allow rotation of one element relative to the other about an axis which extends transversely to at least one of the said elements when the two are so connected.

The said first end region preferably comprises a said generally radially outwardly directed flange and the said second end region preferably comprises a said generally radially inwardly directed recess adapted to receive the said radially outwardly directed flange.

The said second end region may comprise a pair of opposed said radially inwardly directed recesses, each said recess being located so as to be in an upper region of a respective one of the side walls of the second end region when in use.

Preferably the said radially inwardly directed projections are each configured so as to extend downwardly from an upper portion of a respective one of the said side walls of the said second end region and terminate above the said base of the said second end region when m use.

The said second end region may comprise a said generally radially inwardly directed flange and the said first end region may comprise a said generally radially outwardly directed recess adapted to receive the said radially inwardly directed flange.

The said first end region may comprise a pair of opposed said radially outwardly directed recesses, each said recess being located so as to be in an upper region of a respective one of the said side walls of the said first end region when in use.

Each said recess may be defined on an axially inner side by an axially outwardly facing shoulder and an axially outer side by a radially outwardly directed projection.

Preferably the said axially outwardly facing shoulder defining each recess is part of a single axially outwardly facing shoulder extending around substantially the entire periphery of the first end region.

It is particularly preferred that the said seat comprises a formation in a part thereof that is defined by the said base of the second end region, the said formation being adapted to co-operate with a formation provided in the said first end region in such a manner as to assist relative lateral and/or circumferential alignment between the two elements when connected together, yet allow the said rotation of one element relative to the other about the said transverse axis. The said seat is preferably provided with an axially extending slot for receiving an axially extending tongue provided in the first end region.

It is also preferred that the said base of the first end region comprises a formation which is adapted to co-operate with a formation provided in the said seat in such a manner as to assist relative lateral and/or circumferential alignment between the two drainage channel elements when connected together, yet allow the said rotation of one element relative to the other about the said transverse axis.

Preferably the said first end region is provided with an axially extending, radially outwardly projecting tongue for entering an axially extending slot provided in the said seat.

At least one of the said elements may be a drainage channel section or a sump unit.

A third aspect of the invention provides a drainage channel assembly comprising a drainage channel element according to the first aspect of the invention or comprising a drainage channel system according the second aspect of the invention.

A fourth aspect of the invention provides a method of connecting a first drainage channel element according to the second aspect of the invention to a second drainage channel element according to a second aspect of the invention, the said method comprising: laying the said second drainage channel element in position; presenting the said first end region to the said seat; lowering the said first end region into the said seat, so as to effect engagement between the said radially outwardly directed flange or recess and the said radially inwardly directed flange or recess; and rotating the said second drainage channel element relative to the said first drainage channel element about the said transverse axis.

Preferred embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a perspective view of an embodiment of a drainage channel element in accordance with the invention, the said drainage channel element being a drainage channel section fitted with a slotted cover; Figure 2 is a perspective view of a first end region of the drainage channel section of Figure 1; Figure 3 is a close-up partial view of the first end region of the drainage channel section of Figure 1; Figure 4 is a perspective view of a second end region of the drainage channel section of Figure 1; Figure S is a perspective view of end portions of two drainage channel sections such as shown in Figure 1 being presented to one another for jointing; Figure 6 corresponds to Figure 5, but shows the two drainage channel sections in the process of being jointed; Figure 7 is a view corresponding to Figures 5 and 6, but showing the drainage channel sections after they have been connected together; Figure 8 is a view of a second embodiment of a drainage channel element in accordance with the invention, the said drainage channel element being a drainage channel section fitted with a slotted cover; and Figure 9 is a view of a third embodiment of a drainage channel element in accordance with the invention, the said drainage channel element being a sump unit comprising a filter bucket.

Referring to Figure 1, a drainage channel element 1 in accordance with a first embodiment of the invention takes the form of a drainage channel section. The section 1 comprises an elongate body 8 defined by side walls 2 interconnected by a base 4.

Although the base 4 is arcuate in cross-section in this particular embodiment, it is not limited to this shape and may assume any convenient shape, many examples of which are well known in the art.

The elongate body 8 is provided with a series of large ribs 14 and small ribs 15 which each extend radially outwardly from the body 8 at intervals. The large ribs 14 have generally mutually perpendicular lower and side surfaces, so that together they give a somewhat rectangular crosssectional shape to the maximum periphery of the body 8.

The large ribs 14 are used for supporting the section 1 when installed, in a generally conventional manner.

A first end region 3 of the body 8 is provided with a radially outwardly extending flange 7, which extends around substantially the entire outer periphery of the side walls 2 and base 4, as can be seen in Figure 2. Figure 3 shows a close-up partial view of the upper portion of one end of the flange 7; the other side corresponds. As will be seen from this figure, the flange 7 is provided with an axially projecting fulcrum pad 22A,B on each axial side in each of two opposite distal end regions. Fulcrum pads 22A are directed axially outwardly and fulcrum pads 22B are directed axially inwardly.

At an opposite, second end region 5, the body 8 is provided with a radially inwardly directed seat 6. The seat 6 is provided with a pair of opposed recesses 9, which are each directed radially inwardly. The recesses 9 each extend from a region that is intended to be generally uppermost when the drainage channel section 1 is installed for use, down to a point where the side walls 2 join the base 4.

The recesses 9 are each defined on an axially innermost side by an axially outwardly facing shoulder 10 and on an axially outermost side by a respective elongate projection 11. The shoulder 10 is common to both recesses and extends around substantially the entire inner perimeter of the side walls 2 and base 4.

A keel 16 extends axially along substantially the entire length of the body 8, in the middle of the base 4, equidistant the two side walls 2.

The seat 6 is provided with a central, axial slot 13 at a location midway between the two side walls 2, and in substantially the same lateral position as the keel 16.

The distal ends of the side walls 2, which are intended to be located at ground level in use, are provided with respective elongate rebates 18, which extend along the entire length of the body 8. The rebates 18 receive a slotted cover 20 in a generally conventional manner.

The procedure for jointing an element such as section 1 to another (in this case identical) drainage channel element 1, to form part of a drainage channel assembly, will now be described with particular reference to Figures 5-7. Although the two drainage channel sections shown in Figures 5-7 are identical to the one shown in Figure 1, they will be referred to as "Sections A and B" for the purpose of describing their connection together.

Referring initially to Figure 5, it will be seen that the first end region 3 of Section A is presented to the second end region 5 of Section B in an elevated condition, with its base 4 above the uppermost part of the recesses 9 of Section B. Section A is moved axially towards Section B until the flange 7 of Section A is substantially axially aligned with the recesses 9 of Section B. Once this axial alignment has taken place, the first end region 3 of Section A is lowered gradually into the second end region 5 of Section B. as shown in Figure 6. For this to be possible, the lateral separation of the side walls 2 in the region of the seat 6 is greater than the outer periphery of the side walls in the first end region 3. Similarly, the radially inner diameter of the base 4 in the second end region 5 is greater than the radially outer diameter of the base in the first end region 3.

The first end region 3 of Section A is further lowered until the end of its keel 16 addresses the axial slot 13 provided in the seat 6 of the second end region of Section B. Further lowering of the first end region 3 of Section A introduces the keel 16 into the slot 13, until the base 4 of Section A rests in the seat 6 of Section B. as shown in Figure 7.

Figure 7 shows the completed junction between Sections A and B where the first end region 3 of Section A is completely received within the seat 6 of Section B. with the keel 16 of the Section A fully accommodated within the axial slot 13 of Section B and the flange 7 of Section A fully received within the recesses 9 of Section B. In each of the above embodiments, the axial thickness of the flange 7 is 4.5mm, whilst the axial width of the recesses is 6.5mm. This gives an axial clearance of 2mm in total.

The fulcrum pads 22A,B each project axially by a distance of 0.75mm, which means that the total axial clearance between the walls of the recesses and the flange/fulcrum pads combination is 0.5mm. These values are not an essential requirement of the invention and other values will suit different circumstances. It has however been found that an axial clearance of 1-3mm is particularly beneficial. It has further been found that it is beneficial if the fulcrum pads have an axial projection in the range of 0.5- l.Smm. The distribution of the axial clearance on either side of the flange 7 need not be uniform - it could even be located entirely on one axial side (in the region of the fulcrum pads), depending upon how the elements are located relative to one another by the fitter. It is further the case that not all the fulcrum pads need have that same degree of axial projection, although it is preferred that they do.

Because the recesses 9 extend only partly around the perimeter of the seat 6, the flange 7 is not constrained at all in the region of the bases 4. There is therefore a stepped, downward decrease in the amount of axial constraint imposed upon the flange 7 within the seat 6. This allows a degree of axial rotation of one element relative to another about a transverse axis situated generally in the region of the fulcrum pads. The precise location of the axis used for any particular rotation will depend upon the relative axial positions of the two elements at the time of rotation. For example, if fulcrum pads 22A of section A are abutted against the axial shoulder 10 of Section B (as shown in Figure 7), then the axis of rotation will be T1. This will allow rotation as shown generally by arrow R. However, if fulcrum pads 22B are abutted against elongate projection 11, then the axis of rotation will be T2. These represent extremes and the axis could be located between T1 and T2 depending upon the relative axial positioning of the two elements prior to rotation. It is also the case that rotation can occur about axes that are located lower down in the region of the overlap between the two end regions, due to the nature of the axial clearances between the flange and the recesses. In each case the arc of rotation will be slightly different, but there will be at least general correspondence with arrow R in Figure 7.

During rotation, the relative circumferential positions of the two elements are secured by the reception of the keel 16 of Section A within the axial slot 13 of the seat 6 of Section B. The nature of the junction between the two Sections A, B is such that relative axial movement is substantially constrained, but a range of upward and downward rotation of one relative to the other is allowed. This imparts a degree of flexibility to the drainage channel assembly, once a series of sections are connected together such as shown in Figures 5-7 and described above. Consequently, the assembled structure can accommodate irregularities in the ground upon which it is being laid and also accommodate ground movement after installation. By accommodating irregularities in the ground, installation is made considerably more easy and by accommodating ground movement, the drainage channel assembly is made much more resistant to failure.

It will be noted that the small ribs 15 each have a configuration that is substantially identical to the flange 7. This means that the channel section can be cut adjacent one of the small ribs 15 to form a section of a shorter length, because the small rib 15 becomes a new flange 7 in a new first end region.

Although the described embodiment is in the form of a channel section, the invention is not limited to channel sections and may include a wide range of other drainage channel elements. Examples of two of these are shown in Figures 8 and 9, but it should be understood that these are mere examples of elements which can embody the invention, there being many more in practice.

Figure 8 shows a different type of drainage channel section to those shown in Figures 1 to 7. It is longer and includes a vertical outlet towards one end. Figure 9 shows a sump unit fitted with a filter bucket. The section of Figure 8 has a first end region and a second end region that are exactly the same as those of the first embodiment described above and other elements in the system share this feature. This means that each such element may be connected anywhere in a drainage channel assembly by connecting each of its ends with a respectively adjacent element from the system, regardless of what type of element the adjacent one is. However, not all elements of this drainage channel system according to the invention need have both a first end region and a second end region as described above. Some elements may have just one or the other or even two of the same kind. The sump unit of Figure 9 is such an element, in that it is provided with two second end regions, but no first end region. Other types of such elements include adaptors, which are to be connected to something not forming part of the system.

As will be apparent from the foregoing, if the element is not generally channel-shaped, it will still include an essentially channel-shaped portion in each first and/or second end region that it might have. In such a case, each end region will include its own respective side walls and base portion.

It is preferred that drainage channel elements according to the invention are injection moulded using polypropylene, but PVC and polyethylene are viable alternatives. The cover may also be made from steel or even cast iron, particularly if a heavy-duty use is envisaged.

Although there are many possible variations within the scope of the invention, one preferred alternative embodiment reverses the radial orientation of the flange 7 and the recesses 9. In this case, the flange is directed radially inwardly and is located in the seat and the recesses are directed radially outwardly and are situated in the element's second end region. It should also be understood that although the recesses 9 terminate above the base in the above embodiments, a similar effect could be achieved by terminating the flange 7 in a similar fashion. In such a case the recesses could have any desired length, even extending around the entire periphery of the end region, so as to form a single continuous recess.

In other embodiments the fulcrum pads are omitted or replaced with alternative formations that serve to assist to relative rotation between adjacent elements. Numerous further variations are possible by varying the relative dimensions of the recesses and/or flanges (or equivalent formations) - one effect of this being a variation in the degree of relative element rotation afforded by the system.

Many further modifications and variations will suggest themselves to those versed in the art upon making reference to the foregoing illustrative embodiments, which are given by way of example only and which are not intended to limit the scope of the invention, that being determined solely by the appended claims.

Claims

CLAIMS: 1. A drainage channel element comprising a body having a first end

region and a second, opposite end region, each said end region comprising a pair of opposed side walls interconnected by a base, wherein the said first end region is further provided with a generally radially outwardly directed flange or recess and the said second end region is further provided with a seat, the said seat comprising a generally radially inwardly directed flange or recess which is adapted to engage with a said flange or recess provided in the first end region of another drainage channel element in such a manner as to constrain relative axial displacement between the two elements, yet allow rotation of one element relative to the other about an axis which extends transversely to at least one of the said element and the said another element when the two are so connected.
2. A drainage channel element according to Claim 1, wherein the said first end region comprises a said generally radially outwardly directed flange and the said second end region comprises a said generally radially inwardly directed recess adapted to receive a said radially outwardly directed flange from another drainage channel element.
3. A drainage channel element according to Claim 2, wherein the said second end region comprises a pair of opposed said radially inwardly directed recesses, each said recess being located so as to be in an upper region of a respective one of the side walls of the second end region when in use.
4. A drainage channel element according to Claim 3, wherein each said recess is defined on an axially inner side by an axially outwardly facing shoulder and an axially outer side by a radially inwardly directed projection.
5. A drainage channel element according to Claim 4, wherein the said axially outwardly facing shoulder defining each recess is part of a single axially outwardly facing shoulder extending around substantially the entire periphery of the second end region.
6. A drainage channel element according to Claim 4 or Claim S. wherein the said radially inwardly directed projections are each configured so as to extend downwardly from an upper portion of a respective one of the said side walls of the said second end region and terminate above the said base of the said second end region when in use.
7. A drainage channel element according to Claim 1, wherein the said second end region comprises a said generally radially inwardly directed flange and the said first end region comprises a said generally radially outwardly directed recess adapted to receive a said radially inwardly directed flange from another drainage channel element.
8. A drainage channel element according to Claim 7, wherein the said first end region comprises a pair of opposed said radially outwardly directed recesses, each said recess being located so as to be in an upper region of a respective one of the said side walls of the said first end region when in use.
9. A drainage channel element according to Claim 8, wherein each said recess is defined on an axially inner side by an axially outwardly facing shoulder and an axially outer side by a radially outwardly directed projection.
10. A drainage channel element according to Claim 9, wherein the said axially outwardly facing shoulder defining each recess is part of a single axially outwardly facing shoulder extending around substantially the entire periphery of the first end region.
11. A drainage channel element according to any one of Claims 2 to 6, wherein the said radially outwardly directed flange extends around substantially the entire periphery of the said first end region.
12. A drainage channel element according to any preceding claim, wherein the said seat comprises a formation in a part thereof that is defined by the said base of the second end region, the said formation being adapted to co-operate with a formation provided in a said first end region of another drainage channel element in such a manner as to assist relative lateral and/or circumferential alignment between the two elements when connected together, yet allow the said rotation of one element relative to the other about the said transverse axis.
13. A drainage channel element according to Claim 12, wherein the said seat is provided with an axially extending slot for receiving an axially extending tongue provided in a first end region of another drainage channel element.
14. A drainage channel element according to any preceding claim, wherein the said base of the first end region comprises a formation which is adapted to co-operate with a formation provided in a said seat of another drainage channel element in such a manner as to assist relative lateral andlor circumferential alignment between the two drainage channel elements when connected together, yet allow the said rotation of one element relative to the other about the said transverse axis.
15. A drainage channel element according to Claim 14, wherein the said first end region is provided with an axially extending, radially outwardly projecting tongue for entering an axially extending slot provided in a said seat of another drainage channel element.
16. A drainage channel element according to any preceding claim, wherein either the said first end region or the said second end region comprises a fulcrum formation for defining the said transverse axis.
17. A drainage channel element according to Claim 16, wherein the said fulcrum formation takes the form of a projection.
18. A drainage channel element according to Claim 17, wherein the said projection defining the fulcrum formation is situated on an axially facing surface of the said flange.
19. A drainage channel element according to any preceding claim, wherein the said element is a drainage channel section.
20. A drainage channel element according to any one of Claims 1 to 1 S. wherein the said element is a sump unit.
21. A drainage channel system comprising a first drainage channel element and a second drainage channel element, the said first element comprising a body having a first end region and the said second element comprising a body having a second end region, each said end region comprising a pair of opposed side walls interconnected by a base; wherein the said first end region is further provided with a generally radially outwardly directed flange or recess and the said second end region is Farther provided with a seat, the said seat comprising a generally radially inwardly directed flange or recess which is adapted to engage with the said flange or recess provided in the first end region in such a manner as to constrain relative axial displacement between the two elements, yet allow rotation of one element relative to the other about an axis which extends transversely to at least one of the said elements when the two are so connected.
22. A drainage channel system according to Claim 21, wherein the said first end region comprises a said generally radially outwardly directed flange and the said second end region comprises a said generally radially inwardly directed recess adapted to receive the said radially outwardly directed flange.
23. A drainage channel system according to Claim 22, wherein the said second end region comprises a pair of opposed said radially inwardly directed recesses, each said recess being located so as to be in an upper region of a respective one of the side walls of the second end region when in use.
24. A drainage channel system according to Claim 23, wherein each said recess is defined on an axially inner side by an axially outwardly facing shoulder and an axially outer side by a radially inwardly directed projection.
25. A drainage channel system according to Claim 24, wherein the said axially outwardly facing shoulder defining each recess is part of a single axially outwardly facing shoulder extending around substantially the entire periphery of the second end region.
26. A drainage channel system according to Claim 24 or Claim 25, wherein the said radially inwardly directed projections are each configured so as to extend downwardly from an upper portion of a respective one of the said side walls of the said second end region and terminate above the said base of the said second end region when in use.
27. A drainage channel system according to Claim 21, wherein the said second end region comprises a said generally radially inwardly directed flange and the said first end region comprises a said generally radially outwardly directed recess adapted to receive the said radially inwardly directed flange.
28. A drainage channel system according to Claim 27, wherein the said first end region comprises a pair of opposed said radially outwardly directed recesses, each said recess being located so as to be in an upper region of a respective one of the said side walls of the said first end region when in use.
29. A drainage channel system according to Claim 28, wherein each said recess is defined on an axially inner side by an axially outwardly facing shoulder and an axially outer side by a radially outwardly directed projection.
30. A drainage channel system according to Claim 29, wherein the said axially outwardly facing shoulder defining each recess is part of a single axially outwardly facing shoulder extending around substantially the entire periphery of the first end region.
31. A drainage channel system according to any one of Claims 22 to 26, wherein the said radially outwardly directed flange extends around substantially the entire periphery of the said first end region.
32. A drainage channel system according to any preceding claim, wherein the said seat comprises a formation in a part thereof that is defined by the said base of the second end region, the said formation being adapted to co-operate with a formation provided in the said first end region in such a manner as to assist relative lateral and/or circumferential alignment between the two elements when connected together, yet allow the said rotation of one element relative to the other about the said transverse axis.
33. A drainage channel system according to Claim 32, wherein the said seat is provided with an axially extending slot for receiving an axially extending tongue provided in the first end region.
34. A drainage channel system according to any preceding claim, wherein the said base of the first end region comprises a formation which is adapted to co-operate with a formation provided in the said seat in such a manner as to assist relative lateral and/or circumferential alignment between the two drainage channel elements when connected together, yet allow the said rotation of one element relative to the other about the said transverse axis.
35. A drainage channel system according to Claim 34, wherein the said first end region is provided with an axially extending, radially outwardly projecting tongue for entering an axially extending slot provided in the said seat.
36. A drainage channel system according to any of Claims 20 to 35, wherein either the said first end region or the said second end region comprises a fulcrum formation for defining the said transverse axis.
37. A drainage channel system according to Claim 36, wherein the said fulcrum formation takes the form of a projection.
38. A drainage channel system according to Claim 37, wherein the said projection defining the fulcrum formation is situated on an axially facing surface of the said flange.
39. A drainage channel system according to any preceding claim, wherein at least one of the said elements is a drainage channel section.
40. A drainage channel system according to any one of Claims 21 to 38, wherein at least one of the said elements is a sump unit.
41. A drainage channel assembly comprising a drainage channel element according to any of Claims 1 to 20 or comprising a drainage channel system according to any of claims 21 to 40.
42. A method of connecting a first drainage channel element according to any of Claims 21 to 40 to a second drainage channel element according to any of Claims 21 to 40, the said method comprising: laying the said second drainage channel element in position; presenting the said first end region to the said seat; lowering the said first end region into the said seat, so as to effect engagement between the said radially outwardly directed flange or recess and the said radially inwardly directed flange or recess; and rotating the said second drainage channel element relative to the said first drainage channel element about the said transverse axis.
43. A drainage channel element substantially as hereinbefore described with reference to figures 1 to p; or figure 7; or figure jofthe accompanying drawings. ) 1