The present invention relates to inspection chambers, manholes, access junctions and similar products which provide access to sewer or drainage systems, and in particular to a stacking aid for such products . The invention also relates to an assembly of such a stacking aid and an inspection chamber.

Drainage and sewer systems generally include underground pipes which, through use, are prone to becoming blocked or damaged.

As pipes may run for a considerable distance underground, it is desirable to provide access to the pipes at various positions, and particularly where the pipe is joined to one or more other pipes . Such access is provided by an inspection chamber. In this application, the term "inspection chamber" is used to include manholes, access junctions and similar products which provide access to sewer or drainage systems .

To transport inspection chambers to building sites, inspection chambers are conventionally packed in cardboard boxes or wrapped in a transparent plastic film and are then placed on palettes ready for transportation. The use of cardboard boxes allows easy stacking of the inspection chambers on a palette , but requires a great deal of cardboard and therefore increases the price of the inspection chamber . Packing the inspection chambers individually in cardboard boxes is also time- consuming . Transparent film is sometimes used to package the inspection chambers as this affords some protection to the inspection chamber whilst facilitating stacking of the product. However, this type of packaging is not ideal in locations where the inspection chambers are stored in their packaging in direct sunlight , as this can cause the inspection chambers to overheat and to eventually deform .

The present invention addresses the problems associated with transportation and storage of inspection chambers as mentioned above by providing a stacking aid for inspection chambers as well as an improved inspection chamber which permits stable stacking for transportation and storage.

According to the present invention in one aspect thereof there is provided an inspection chamber stacking aid for locating between inspection chambers to allow stable stacking of the inspection chambers, the stacking aid comprising at least one support structure configured to extend from an exterior surface of a first inspection chamber into an interior of a second inspection chamber and/or adjacent to an exterior surface of a wall defining the interior of the second inspection chamber to thereby reduce movement of the first and second inspection chambers relative to each other in a direction perpendicular to the direction of stacking.

The stacking aid may be inserted between the chambers during stacking. The stacking aid may be configured to be detachably attached to an inspection chamber. Alternatively the stacking aid may be configured to be permanently affixed to an inspection chamber.

According to the present invention in another aspect thereof there is provided an assembly of an inspection chamber stacking aid and an inspection chamber, the inspection chamber comprising; an interior defined by a wall extending around the side and base of the chamber;

at least two openings, each opening being for connecting to a pipe, the openings being located in the wail,

and the stacking aid comprising;

at least one support structure for locating on, or located on, an exterior surface of the wall of the chamber, the support structure, once so located, protruding from the surface of the wall .

The at least one support structure preferably comprises at least one of the group consisting of: an arcuate portion; a circular portion; an elliptical portion; a rectangular portion; a square portion; a triangular portion; a straight line portion; a discrete portion.

The at least one support structure may be formed integrally with the wall defining the interior of the chamber. Alternatively, the at least one support structure may be formed separately from and may be permanently affixed to or detachably attached to the wall defining the interior of the chamber .

Preferably the at least one support structure is for locating on _. , or is located on, the exterior surface of a portion of the wall defining the base of the chamber.

Where a plurality of support structures is provided, the support structures preferably comprise at least one arcuate portion. Advantageously, two arcuate portions are provided. One or more further support structures, preferably being discrete or straight line portions, may also be provided. The support structures may be connected or arranged together, or may be located separate from each other.

Alternatively, where a plurality of support structures is provided, the support structures may comprise at least three discrete or straight line portions, the support structures being arranged around the exterior surface of a portion of a wall defining the base of the chamber. The support structures may be located adjacent the openings in the wall. Such support structures may be, for example, a rod or a flange which extends from the exterior surface of the wall defining the chamber .

Advantageously, the at least one support structure is sized to fit snugly against the interior surface of the wall of the chamber around at least part of its periphery. Alternatively or additionally, the at least one support structure may be sized to fit against the exterior surface of the wall of the chamber around at least part of its periphery. The periphery of the wall of the chamber defines the entrance to the chamber and is located at the top of the chamber opposite to the portion of the wall defining the base of the chamber, Advantageously, the periphery of the wall defining the entrance to the chamber lies in a plane, and the at least one support structure protrudes from the exterior surface of a portion of the wall defining the base of the chamber, in a direction substantially perpendicular to this plane.

In addition to the at least one support structure described above, an eyelet may also be provided. Advantageously the inspection chamber further comprises at least one eyelet located on an exterior surface of the wall of the chamber. The at least one eyelet is preferably located at a position remote from the position of the at least one support structure .

The eyelet may be formed integrally with the wail defining the chamber. Alternatively, the eyelet may be formed separately from the wall defining the chamber, and ma be permanently affixed to or detachably attached to the wall defining the chamber. The eyelet may be formed, in a flange extending from the exterior surface of the wall defining the chamber.

Advantageously, at least one pair of eyelets is provided, each eyelet of the pair being positioned at opposite sides of the chamber from each other. Several pairs of eyelets may be provided, allowing the eyelets to be positioned around the chamber. Preferably two pairs of eyelets are provided, one pair being positioned together at one side of the chamber, and the other pair being positioned together at an opposite side of the chamber from the first pair.

The present invention also provides a plurality of inspection chambers, the at least one support structure of one of the inspection chambers being configured to abut an interior surface of the wall and/or an exterior surface of the wall of another inspection chamber around at least part of its periphery, to thereby enable stacking of the inspection chambers .

Accordingly, the present invention allows a plurality of inspection chambers to be stacked in a stable manner during transportation and storage. This provides the advantages that the inspection chambers require less storage space and fewer packaging materials. This in turn decreases the cost associated with transporting and storing the inspection chambers .

The present invention will now be described by way of example only, and with reference to the following drawings, of which:

Figure 1 shows an isometric view of an inspection chamber having two openings and two support structures and being in accordance with the present invention.

Figure 2 shows a partial isometric view of an inspection chamber similar to that shown in Figure 1.

Figure 3 shows an isometric view of another inspection chamber having four openings and four support structures and being in accordance with the present invention.

Figure 4 shows an isometric view of yet another inspection chamber having four openings and four support structures and being in accordance with the present invention.

Figure 5 shows an isometric view of an inspection chamber having four openings and three support structures according to another embodiment of the invention.

Figure 6 shows an isometric view of another inspection chamber having four openings and one support structure in accordance with the present invention. Figure 7 shows a plan view of an inspection chamber having two openings and two support structures similar to the inspection chambers shown in Figures 1 and 2.

Figure 1 shows an inspection chamber 1 having two openings 11, each opening being for receiving an inlet pipe (or a connection portion for an inlet pipe) and an outlet pipe (or a connection portion for an outlet pipe) , respectively. A wall 3 surrounds and defines an interior of the chamber (reference numeral 9 in Figure 3) , The wall 3 defines a base 7 of the chamber and a side wall 5, the side wall extending around, the chamber. The openings 11 are formed in the side wall 5 close to the base . Opposite to the base 7 of the chamber is the top of the chamber which has an entrance defined by the rim or periphery 21 of the wall defining the chamber. The entrance provides access to the chamber. In this example, the exterior surface of the wall 19 is provided with reinforcing ribs 13. The ribs 13 are optional and are provided where further strengthening of the inspection chamber is required. Two support structures in the form of arcuate portions ISA and 15B are provided on the exterior surface 19 of the wall 3 at the base portion 7. The arcuate portions 15A and 15B are curved inwardly towards the center of the base of the inspection chamber, and have a radius of curvature slightly greater than the radius of curvature of the periphery 21 of the chamber wall 3, The arcuate portions 15A and 15B are each also provided with side flanges 12 , and a notch 17 extending between the side flanges and the arcuate portions 15A and 15B. This permits several inspection chambers to be stacked one on top of the other in a stable manner, because, when the inspection chambers are stacked, the periphery 21 of the wail 3 of one inspection chamber is located in the notches 17 of another inspection chamber, and the arcuate portions 15A and 15B extend around part of the exterior surface 19 of the periphery of the wall 3. Ideally, the arcuate portions fit snugly around the chamber wall of the adjacent chamber, thereby preventing lateral movement of the inspection chamber when it is stacked on another inspection chamber, and ensuring that the stacked inspection chambers remain in their stacked configuration during transportation. The arcuate portions maybe formed as an integral part of the wail 3, or may alternatively be permanently affixed to or removably attached to the exterior surface 13 of the wall as desired . The arcuate portions may take the form of a solid curved strip as shown in Figure 1, or may take the form of a rail mounted on a plurality of supports as shown in Figure 2.

Turning now to Figure 2, Figure 2 shows an inspection chamber similar to that shown in Figure 1, except that the arcuate portions of the inspection chamber 1 of Figure 2 are in the form of L-shaped flanges or rails 35 mounted on supports 37, The arrangement shown in Figure 2 has the advantage of requiring less material to form the arcuate portions . The L- shaped flange may be detachable from the supports 37, The L- shaped flange 35 of Figure 2 comprises a wall 39 and a base 41. In this example, the radius of curvature of the arcuate portions 15A and 15B is greater than that of the periphery 21 of the wall of the chamber such that, when the inspection chambers are stacked, the wall 39 of the L-shaped flange 35 surrounds the exterior surface 19 of the periphery 21 of the chamber wall 3 whilst the base 41 of the L- shaped flange supports the periphery 21 of the chamber wall 3. Thus it can be seen that the L-shaped flange provides a stable support for a neighbouring inspection chamber, permitting the inspection chambers to be easily and stably stacked together.

The arcuate portions also help to maintain the shape of the periphery 21 of the wall 3 defining the chamber by preventing deformation of the periphery 21 during transportation of the stacked inspection chambers.

It will be appreciated that, although the arcuate portions 15A and 15B of Figures 1 and 2 are shown as having a radius of curvature slightly greater than that of the periphery 21 of the wall of the chamber, the radius of curvature of the arcuate portions could instead be slightly less than the radius of curvature of the periphery of the chamber wall. In this case, when the inspection chambers are stacked, the arcuate portions of one chamber will extend within the adjacent chamber abutting part of the interior surface of the periphery of the chamber wall .

Although Figure 2 shows support structures having the form of an L-shaped flange, it will also be appreciated that support structures having a U-shaped cross -section could be provided instead. In this case, the periphery of the chamber wall of the inspection chambers fits within the central groove of the U-shape and the side portions of the D-shape extend around part of both the interior and exterior surfaces of the chamber wall, thereby providing stable stacking.

Figure 3 shows an inspection chamber 1 having four openings 11, for receiving four pipes. Arcuate portions 15A and 15B similar to those shown in Figure 1 are provided on the exterior surface 19 of the wall 3 in the base region 7. The inspection chamber further includes two more support structures 25 , each of the support structures 25 being located adjacent an opening and. extending away from the exterior surface 19 of the wall 3 in a manner similar to that of the arcuate portions 15A and 15B . The support structures 25 are shown in Figure 3 as being discrete portions having a rectangular cross section, however other cross-sectional shapes are possible . The support structures 25 are provided adjacent the openings which are not provided with an arcuate portion. The support structures 25 provide the stacked inspection chambers with even greater stability .

Figure 4 shows an inspection chamber similar to that shown in Figure 3. As the inspection chamber of Figure 4 is required to be more robust than that of Figure 3 , the inspection chamber of Figure 4 is provided with reinforcing ribs 13. The inspection chamber 1 of Figure 4 further differs from that of Figure 3 in that the openings 11 for receiving the pipes are not configured to be 90° apart from each other, but rather two of the pipes are configured to be offset by 45° rather than 90°. The inspection chamber 1 of Figure 4 is provided, i a similar manner to that of Figure 3, with two further support structures 25, which complement and aid the arcuate portions 15A and 15B in providing enhanced stability during stacking of the product.

Figure 5 shows an inspection chamber similar to that shown in Figure 4, having openings 11 offset by 45° rather than 90°, In this example, no arcuate portions are provided, but instead three support structures 25 are provided, the support structures being in the form of discrete portions. Three support structures, located in the manner shown in Figure 5, allow stable stacking of the inspection chambers. Where four openings are provided, each offset by 90° from each other, four discrete portions can be provided, one above each opening, for improved stacking stability.

Figure 6 shows an inspection chamber similar to that depicted in Figure 3. However, the inspection chamber 1 of Figure 6 does not include two arcuate portions, but instead has a single support structure in the form of a circular portion 12. Circular portion 12 may be sized to fit inside the interior of an adjacent inspection chamber, or may be sized to fit around the exterior of the wall of an. adjacent inspection chamber. The circular portion 12 may comprise an L- shaped flange similar to that of the arcuate portions ISA and 15B shown in Figure 2, to enhance the stability of stacked inspection chambers. Alternatively the circular portion 12 may have a U- shaped cross-section for receiving the periphery of the wall of an adjacent inspection chamber during stacking.

Figure 7 shows an inspection chamber similar to that shown in Figures 1 and 2 (in this example, having no reinforcing ribs 13) in plan view, looking down upon the exterior surface 19 of the base portion 7. A flange 29 is provided on opposite sides of the wall 3 defining the chamber, and eyelets 27 are provided in the flange. The flange 29 may be formed integrally with the wail 3, or may be permanently affixed to or detachably attached to the exterior surface 19 of the wall 3. In this example, two eyelets are provided on each side of the inspection chamber, however it would be equally possible to provide one eyelet on each side of the chamber. Alternatively, just one eyelet may be provided. The function of the eyelet will be described later. The inspection chamber 1 of Figure 7 also includes two arcuate portions ISA and 15B .

The periphery 21 of the wail 3 of the chamber {which defines the rim of the chamber) is not visible in this plan view. However, the rim of the inspection chamber extends within a plane which is parallel to the plane of the surface of the paper on which Figure 7 is drawn, Arcuate portions 15A and 15B protrude from the exterior surface 19 of the wall in a direction perpendicular to the plane of the rim (i.e., in the direction out of the plane of the surface of the paper towards the reader) .

The eyelets 27 are for receiving a strap which is used to bundle together the inspection chambers and helps to keep them stably stacked together and to remain on a palette during transportation. Providing eyelets on both sides of the inspection chamber allows greater flexibility in stacking the products. Furthermore, more than one eyelet may be provided on one side of the product, as is the case in Figure 7. This provides greater flexibility when using straps to tie the inspection chambers together. For example, one of the eyelets might be used to tie the inspection chambers together whilst the other eyelet might be used to strap the inspection chambers to the palette .

From the description and drawings, it will be appreciated that one or more support structures may be provided, and that the support structures may comprise different shapes and configurations, as long as they enable stable stacking of a plurality of inspection chambers as described in this specification.