GB2276405A

GB2276405A - An adaptor frame for supporting a rectangular cover on a circular manhole opening.

Info

Publication number: GB2276405A
Application number: GB9306092A
Authority: GB
Inventors: Francis Sidney Clark; Ronald Francis Clark
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-03-24
Filing date: 1993-03-24
Publication date: 1994-09-28
Also published as: GB9306092D0

Abstract

An adaptor frame 16 is provided for supporting a generally rectangular cover 2 above the circular upper opening of a manhole inspection chamber. The adaptor frame comprises a lower circular flange 18 for engagement with the upper part of the inspection chamber, and an upper rectangular flange 20 for engagement with the rectangular cover. The cover may be formed with an upper recess 4 adapted to receive surface material, such as paving blocks. A raised region 6 may be provided around the recess comprising of for triangular areas 8 each having a lifting hole 10. <IMAGE>

Description

"Improvements in or relations to manhole inspection chambers" The invention relates to an adaptor frame and cover assembly for use with manhole inspection chambers.

Manhole inspection chambers allow inspection of underground services, such as sewers, and sometimes comprise a large vertical cylindrical plastic tube which is covered at its upper end by a circular iron or steel manhole cover. The manhole cover is attached to the top of the plastic tube by means of a circular frame which has a lower circular flange for engaging within the upper circular opening of the plastic tube, and an upper circular flange for engaging with the manhole cover. Such manhole covers are often highly conspicuous, and stand out in a noticeable way from the surrounding surface material.

Furthermore, if the surrounding surface is covered using paving blocks, stones or bricks, these must be carefully cut to match the peripheral shape of the manhole cover.

The invention seeks to overcome some of the disadvantages-of the prior art.

According to the invention there is provided an adaptor frame for supporting a generally rectangular cover above the circular upper opening of a manhole inspection chamber, the adaptor frame comprising lower engagement means for engagement with the upper part of the inspection chamber forming said upper opening, and upper engagement means for engagement with the rectangular cover.

It will be appreciated that in many circumstances a rectangular cover is more convenient to use and/or more pleasing to the eye. This is particularly true where the surrounding surface is covered with paving blocks or stones, which are themselves usually rectangular. The use of a rectangular cover can remove the need for surrounding paving material to be cut into awkward shapes. Furthermore, if the rectangular cover is provided with a recess for receiving paving blocks or stones, the surface of the cover can be made to match the surrounding surface material, again without the need to cut the paving material of the cover into awkward shapes.

Preferably, the lower engagement means comprises a downwardly directed flange.

In this case, the flange may be generally circular.

Desirably, the upper engagement means comprises a generally rectangular upwardly directed flange which, when the rectangular cover is located in position so as to close said upper opening, extends around the periphery of the rectangular cover.

In this case, the upwardly directed flange may be supported by a generally rectangular base portion formed with a generally circular aperture for allowing access to the inspection chamber.

The invention also provides a manhole cover assembly comprising an adaptor frame as described above and a generally rectangular cover for covering the upper opening of a manhole inspection chamber.

The rectangular cover may be formed with an upper recess adapted to receive surface material, such as paving blocks.

The upper recess is preferably provided with a plurality of planar side walls.

This has the advantage of allowing the upper recess to be filled with paving blocks which have been cut along straight, rather than curved lines.

The rectangular cover may be formed, for example at its corners, with one or more lifting holes adapted to receive a suitable lifting implement.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a plan view of the top of an inspection chamber, the left half of the figure showing the left half of a rectangular cover in position; Figure 2 shows a section along the line A-A in Figure 1; and Figure 3 shows a section along the line B-B in Figure 1.

The cover 2 is used to cover the upper circular opening of an inspection chamber (not shown), and comprises a central recessed region 4, and an outer raised region 6 which extends around the periphery of the recessed region 4. The raised region 6 comprises four triangular portions 8 located at the corners of the cover 2. Each triangular portion 8 is formed with a recess 10 which acts as a lifting hole in accordance with British Standard No. 497.

The recessed region 4 of the cover 2 is adapted to be filled with block paviors (not shown). In this way the cover 2 can be made to blend in with a surrounding surface 12 which is also covered with block paviors.

Furthermore, since the eight side walls 14 of the recessed region 4 are all flat, the recessed region 4 can be filled with block paviors in a particularly simple and efficient manner. This is because it is only necessary to cut the block paviors along straight lines, rather than along curved lines as would be necessary, for example, if the recessed region 4 were of circular shape.

Furthermore, since the peripheral shape of the cover 2 is generally rectangular, it is also easier and quicker to fit the block paviors of the surrounding surface 12 around the cover 2 for the same reasons.

The cover 2 is supported by an adaptor frame 16 which is connected to the top of a cylindrical plastic inspection chamber (not shown). The frame 16 comprises two downwardly directed circular flanges 18 which engage with the upper circular rim (not shown) of the plastic inspection chamber.

The frame 16 also comprises an upwardly directed peripheral flange 20 which is generally rectangular in shape, and extends around the cover 2 in order to hold the cover 2 in position.

The frame 16 is also provided with a horizontal outwardly projecting flange 22 which helps to anchor the frame 16 in the surrounding surface material. The flange 22 may be regarded as part of a rectangular base portion 23, which also comprises a horizontal portion 24 within the rectangle defined by the upwardly directed flange 20.

The base portion 23 is formed with a central circular aperture 26 for allowing access through the frame 16 to the inspection chamber below.

The frame 16 further comprises four triangular raised portions 28, which are located within the four corners of the upwardly directed flange 20. These raised portions 28 are adapted to support the triangular portions 8 of the raised region 6 of the cover 2. Each raised portion 28 is integrally formed with the upwardly directed flange 20 and also with the base portion 23 of the frame 16.

Suitable materials for the cover 2 and frame 16 are cast grey iron, cast ductile iron, steel, polypropylene, and glass reinforced plastics. The cover 2 and frame 16 are each formed as single integral units.

It will be appreciated that, once the cover 2 is located within the upwardly directed flange 20 of the frame 16, the only parts of the assembly which are visible are the top of the raised region 6 and the top of the upwardly directed flange 20.

Claims

1. An adaptor frame for supporting a generally rectangular cover above the circular upper opening of a manhole inspection chamber, the adaptor frame comprising lower engagement means for engagement with the upper part of the inspection chamber forming said upper opening, and upper engagement means for engagement with the rectangular cover.

2. An adaptor frame as claimed in claim 1, wherein the lower engagement means comprises a downwardly directed flange.

3. An adaptor frame as claimed in claim 2, wherein the flange is generally circular.

4. An adaptor frame as claimed in any one of claims 1 to 3, wherein the upper engagement means comprises a generally rectangular upwardly directed flange which, when the rectangular cover is located in position so as to close said upper opening, extends around the periphery of the rectangular cover.

5. An adaptor frame as claimed in claim 4, wherein the upwardly directed flange is supported by a generally rectangular base portion formed with a generally circular aperture for allowing access to the inspection chamber.

6. An adaptor frame substantially as hereinbefore described with reference to the accompanying drawings.

7. A manhole cover assembly comprising an adaptor frame as claimed in any one of the preceding claims and a generally rectangular cover for covering the upper opening of a manhole inspection chamber.

8. A manhole cover assembly as claimed in claim 7, wherein the rectangular cover is formed with an upper recess adapted to receive surface material, such as paving blocks.

9. A manhole cover assembly as claimed in claim 8, wherein the upper recess is provided with a plurality of planar side walls.

10. A manhole cover assembly as claimed in any one of claims 7 to 9, wherein the rectangular cover is formed with one or more lifting holes adapted to receive a suitable lifting implement.

11. A manhole cover assembly substantially as hereinbefore described with reference to the accompanying drawings.