GB2376495A

GB2376495A - Frame arrangement for ground surface access assembly

Info

Publication number: GB2376495A
Application number: GB0114469A
Authority: GB
Inventors: Barry Turner
Original assignee: Wrekin Welding and Fabrication Engineering Ltd; Atlanta Impex Ltd
Current assignee: Wrekin Welding and Fabrication Engineering Ltd; Atlanta Impex Ltd
Priority date: 2001-06-14
Filing date: 2001-06-14
Publication date: 2002-12-18
Anticipated expiration: 2021-06-14
Also published as: GB0114469D0; GB2376495B

Abstract

The frame arrangement 12, for use with manholes, gully gratings etc., includes a support portion for mounting a cover member 14 and a flange 30 extending outwardly from the support portion, wherein the support portions includes side portions 32 and corner portions joining the side portions and wherein the flange extends further outwardly from one diagonally opposite pair of corners 34a than it does from another diagonally opposite pair of corners 34b. The support portion is preferably rectangular in plan view with four straight side portions and four curved corner portions. A cover member is preferably supported on one or more seats that extend inwards from an upstanding wall 26 which forms the support portion while the flange extends outwards from the lower part of the upstanding wall. The corner portions may form foot portions which include openings that pass through them and an elongate, circular bead 44 may extend around the full extent of the outer edge of the flange. The frame may support two triangular cover members 16 which each have a main support beam 17 along their longest sides which align with the corners with the largest flanges. The frame may also include a number of projections that are provided on the underside of the flanges.

Description

Ground Surface Access Assemblies The invention relates to ground surface access assemblies, such as manhole assemblies and gully gratings. Such assemblies allow access to sewers, water hydrants and other below surface installations, via openings in the roads, pavements, etc. , above.

A manhole assembly typically includes a generally rectangular frame and a cover member mountable on the frame. The cover member can be lifted from the frame or pivoted relative to the frame in order to allow access to the below surface installation. The frame may include an upstanding wall which is approximately rectangular in plan view, and a flange extending outwardly from a base of the wall. Conventionally, the flange is mounted in a mortar bed to retain the manhole assembly in place.

According to the invention, there is provided a frame arrangement for a ground surface access assembly, the frame arrangement including a support portion for mounting a cover member and a flange extending outwardly from the support portion, wherein the support portion includes side portions and corner portions joining the side portions, and wherein the flange extends further outwardly from one diagonally opposite pair of corner portions than it does from another diagonally opposite pair of corner portions.

Preferably the support portion is generally rectangular in plan view, including four side portions and four corner portions joining the side portions. The side portions are preferably substantially straight and the corner portions curved.

The support portion may include an upstanding wall. The wall may be provided with one or more seats protruding inwardly therefrom. A cover member supported on the support member may be supported on the seats, inwardly of the upstanding wall.

The flange may extend outwardly from a lower part of the upstanding

wall. The flange may be generally planar and may lie approximately parallel to a cover member mounted on the support portion. The flange may have a thickness of between 10mm and 20mm.

The portions of the flange which extend outwardly from the corners of the support portion may comprise foot portions, which may be linked by edge portions extending outwardly from the side portions of the support portion.

The edge portions may extend outwardly from the support portion by between 5mm and 50mm. The smaller foot portions may extend outwardly from the support portion by between 20mm and 100mm. The larger foot portions may extend outwardly from the support portion by between 30mm and 150mm. The smaller foot portions may extend outwardly by the same amount as the edge portions. Alternatively the smaller foot portions may extend further outwardly than the edge portions.

Each foot portion may include one or more openings passing therethrough. Preferably each foot portion includes three openings passing therethrough.

The foot portions may include curved outer edges. An elongate bead may extend around at least a part of the outer edges of the foot portions and preferably extends around the whole outer edge of the flange. The bead may protrude outwardly beyond the upper surface of the flange. The bead is preferably of a smooth curved shape in section and may be substantially circular in section, having a radius of between 5mm and 20mm and preferably about 10mm.

The frame arrangement may be adapted to support a generally rectangular cover member comprising two substantially triangular parts, a main support beam for each triangular part being defined generally along its long side, adjacent to the other triangular part.

Preferably the larger foot portions are provided at the corners of the support portion which are aligned with and support the main beams of the

cover member. The seats of the support portion may be shaped to prevent a cover member being mounted on the frame arrangement with its main beams aligned with the smaller foot portions.

An undersurface of the flange may be provided with a plurality of projections. The projections may be provided in discrete areas, which may be separated by smooth areas. Preferably areas of projections are provided on the undersurfaces of the foot portions.

Preferably the projections do not extend right to the outer edges of the flange, but terminate smoothly in a region spaced from the edge of the flange.

Preferably the projections merge smoothly into the bead.

Preferably the projections have a smooth profile. Preferably the projections result in the profile of the undersurface having alternating peaks and troughs in each of any two mutually perpendicular directions. Preferably the projections provide a resistance to movement of the frame arrangement within mortar in any direction substantially parallel to the general plane of the flange.

Preferably the projections have an undulating profile. The undulations may be regular or periodic. The undersurface of the flange may be provided with a plurality of protruding nodules. The nodules preferably protrude in a direction substantially perpendicular to the general plane of the undersurface of the flange. The nodules may be substantially conical in shape, with blunt or curved peaks. The peaks of the nodules may be between 5mm and 15mm apart and the peaks may extend between 1. 5mm and 5mm, and preferably about 3mm, beyond the troughs.

According to the invention there is further provided a manhole assembly including a frame arrangement according to any of the preceding nine paragraphs and a cover member for mounting on the frame arrangement.

Preferably the cover member is generally rectangular, comprising two

substantially triangular parts, a main support beam for each triangular part being defined generally along its long side, adjacent to the other triangular part.

Preferably the larger foot portions are provided at the corners of the support portion which are aligned with and support the main beams of the cover member. The seats of the support portion may be shaped to prevent a cover member being mounted on the frame arrangement with its main beams aligned with the smaller foot portions.

An embodiment of the invention will be described for the purpose of illustration only with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic plan view of a manhole assembly according to a first embodiment of the invention; Fig. 2 is a diagrammatic plan view of a manhole assembly according to a second embodiment of the invention; and Fig. 3 is a diagrammatic partial cross section through a corner of the manhole assembly of figure 1.

Referring to Fig. 1, there is illustrated a manhole assembly 10 including a frame 12 and a cover 14. The manhole assembly is of type D400, meaning that it is rated to take forces of up to 400kN. The cover 14 is formed of cast metal and comprises two substantially planar triangular parts 16 provided with projections 18 on their upper surfaces. The projections 18 provide for a high friction upper surface of the cover member 14, to allow traffic to pass over the manhole assembly 10 without skidding. Each triangular part 16 includes a main support beam 17 provided along its long side, adjacent the other triangular part. The beam is indicated with dotted lines in Figs. 1 and 2.

The cover 14 is supported at its edges 20 or corners by the frame 12.

Referring to Fig. 3, the frame 12 includes an upstanding wall 26, provided

with seats 28 projecting therefrom in an inward direction. The edges 20 or corners of the cover member are supported on the seats 28.

Referring also to Fig. 1, the wall 26 is generally square in plan view including sides 22 and curved corner regions 24. The seats in one pair of corner regions 24a are aligned with and support the main support beams 17 of the cover member 14.

Extending outwardly from a base region of the upstanding wall 26 is a generally planar flange 30. The flange has a thickness of about 8mm and has upper and lower surfaces 31 and 33 respectively (see Fig. 3). The lower surface 33 is provided with protruding smooth nodules 42. The nodules 42 are generally conical in shape, but have curved peaks. The nodules allow the flange to key into a mortar bed 40 so that the grip between the flange 30 and the mortar bed 40 is not solely reliant on friction between the flange and the mortar, but also on the shear, tensile and compression properties of the mortar.

Friction is also significantly increased by the increase in effective contact area between the mortar and the flange undersurface.

At a perimeter of the flange 30, a generally circular cross section bead 44 is provided. The circular section of the bead 44 helps to minimise the likelihood failure of the mortar. The bead has no corners to concentrate stress or form initiation sites for cracks.

The flange 30 includes relatively narrow side portions 32, extending about 30mm to 40mm outwardly from the upstanding wall 26, and splayed corner portions 34. One pair of diagonally opposite corner portions 34b each extend outwardly from the upstanding walls about 100mm and the other diagonally opposite pair of corner portions 34a each extend outwardly from the upstanding wall 26 by about 120mm.

The manhole assembly illustrated in Fig. 2 is generally similar of that Fig.

1, except that the flange 30 includes only one diagonally opposite pair of splayed corner portions 34a. In this case, the relatively narrow side portions 32

are somewhat wider, being perhaps 40mm to 60mm wide and the corner portions 34b are of the same width. However, the corner portions 34b again extend further outwardly, being about 120mm wide. Each corner portion 34 includes three openings 36 passing therethrough.

In each of the Fig. 1 and Fig. 2 embodiments, the larger corner portions 34a are aligned with the main diagonal beam 17 of the multiple triangular cover. The main beam seats are provided in the corners 24a of the upstanding wall 26 adjacent to the enlarged corner portions 34b. The seats are designed such that the cover 14 can only be mounted with the main beam 17 aligned with the larger corner portions 34a.

The applicant has realised that manhole assemblies are unevenly loaded because the main diagonal beam in all multiple-triangular cover arrangements attracts a predominant proportion of the applied vehicular load and more effectively transfers this load to its frame seating position. In the manhole assembly accordingly to the invention, this vehicular load is transferred more efficiently to the mortar foundation by increasing the area of the flange in the regions where the main diagonal beam of the cover sits on the frame. Thus, the compression stress in the mortar is reduced. It is not necessary to increase the size of the flanges in the other corner portions away from the main beam.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

CLAIMS 1. A frame arrangement for a ground surface access assembly, the frame arrangement including a support portion for mounting a cover member and a flange extending outwardly from the support portion, wherein the support portion includes side portions and corner portions joining the side portions, and wherein the flange extends further outwardly from one diagonally opposite pair of corner portions than it does from another diagonally opposite pair of corner portions.
2. A frame arrangement according to claim 1. wherein the support portion is generally rectangular in plan view, including four side portions and four corner portions joining the side portions.
3. A frame arrangement according to claim 2, wherein the side portions are substantially straight and the corner portions curved.
4. A frame arrangement according to any of claims 1 to 3, wherein the support portion includes an upstanding wall.
5. A frame arrangement according to claim 4, wherein the wall is provided with one or more seats protruding inwardly therefrom.
6. A frame arrangement according to claim 5, wherein a cover member supported on the support member is supported on the seats, inwardly of the upstanding wall.
7. A frame arrangement according to any of claims 4 to 6, wherein the flange extends outwardly from a lower part of the upstanding wall.
8. A frame arrangement according to any of the preceding claims, wherein the flange is generally planar.

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9. A frame arrangement according to any of the preceding claims, wherein the flange lies approximately parallel to a cover member mounted on the support portion.
10. A frame arrangement according to any of the preceding claims, wherein the flange has a thickness of between 10mm and 20mm.
11. A frame arrangement according to any of the preceding claims, wherein the portions of the flange which extend outwardly from the corners of the support portion comprise foot portions and wherein the foot portions are linked by edge portions extending outwardly from the side portions of the support portion.
12. A frame arrangement according to claim 11, wherein the edge portions extend outwardly from the support portion by between 5mm and 50mm.
13. A frame arrangement according to any of claims 11 or 12, wherein the

smaller foot portions extend outwardly from the support portion by between 20mm and 100mm.
14. A frame arrangement according to claim 13, wherein the larger foot portions extend outwardly from the support portion by between 30mm and 150mm.
15. A frame arrangement according to claims 13 or 14, wherein the smaller foot portions extend outwardly by the same amount as the edge portions.
16. A frame arrangement according to claims 13 or 14, wherein the smaller foot portions extend further outwardly than the edge portions.
17. A frame arrangement according to any of claims 11 to 16, wherein each foot portion includes one or more openings passing therethrough.
18. A frame arrangement according to any of claims 11 to 17, wherein the

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foot portions include curved outer edges.
19. A frame arrangement according to claim 18, wherein an elongate bead extends around at least a part of the outer edges of the foot portions.
20. A frame arrangement according to claim 19, wherein the elongate bead extends around the whole outer edge of the flange.
21. A frame arrangement according to claims 19 or 20, wherein the bead protrudes outwardly beyond the upper surface of the flange.
22. A frame arrangement according to any of claims 19 to 21, wherein the bead is of a smooth curved shape in section.
23. A frame arrangement according to claim 22, wherein the bead is substantially circular in section.
24. A frame arrangement according to claim 23, wherein the bead has a radius of between 5mm and 20mm.
25. A frame arrangement according to claim 24, wherein the bead has a radius of about 10 mm.
26. A frame arrangement according to any preceding claim, wherein the frame arrangement is adapted to support a generally rectangular cover member comprising two substantially triangular parts, a main support beam for each triangular part being defined generally along its long side, adjacent to the other triangular part.
27. A frame arrangement according to claim 26 when dependent on claims 11 to 25 wherein the larger foot portions are provided at the corners of the support portion which are aligned with and support the main beams of the cover member.

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28. A frame arrangement according to claim 27, wherein the support portion is shaped to prevent a cover member being mounted on the frame arrangement with its main beams aligned with the smaller foot portions.
29. A frame arrangement according to any of the preceding claims, wherein an undersurface of the flange is provided with a plurality of projections.
30. A frame arrangement according to claim 29, wherein the projections are provided in discrete areas.
31. A frame arrangement according to claim 30, wherein the discrete areas are separated by smooth areas.
32. A frame arrangement according to any of claims 29 to 31, wherein areas of projections are provided on the undersurfaces of the parts of the flange which extend outwardly from the corners of the support portion.
33. A frame arrangement according to any of claims 29 to 32, wherein the projections do not extend right to the outer edges of the flange, but terminate smoothly in a region spaced from the edge of the flange.
34. A frame arrangement according to any of claims 29 to 33, wherein the projections have a smooth profile.
35. A frame arrangement according to any of claims 29 to 34, wherein the projections result in the profile of the undersurface having alternating peaks and troughs in each of any two mutually perpendicular directions.
36. A frame arrangement according to any of claims 29 to 35, wherein the projections provide a resistance to movement of the frame arrangement within mortar in any direction substantially parallel to the general plane of the flange.
37. A frame arrangement according to any of claims 29 to 36, wherein the projections have an undulating profile.

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38. A frame arrangement according to claim 37, wherein the undulations are regular or periodic.
39. A frame arrangement according to any of claims 29 to 38, wherein the undersurface of the flange is provided with a plurality of protruding nodules.
40. A frame arrangement according to claim 39, wherein the nodules protrude in a direction substantially perpendicular to the general plane of the undersurface of the flange.
41. A frame arrangement according to claims 39 or 40, wherein the nodules are substantially conical in shape, with blunt or curved peaks.
42. A manhole assembly including a frame arrangement according to any of the preceding claims and a cover member for mounting on the frame arrangement.
43. A manhole assembly according to claim 42, wherein the cover member is generally rectangular, comprising two substantially triangular parts, a main support beam for each triangular part being defined generally along its long side, adjacent to the other triangular part.
44. A manhole assembly according to claim 43, wherein the larger foot portions are provided at the corners of the support portion which are aligned with and support the main beams of the cover member.
45. A manhole assembly according to claim 44, wherein the seats of the support portion are shaped to prevent a cover member being mounted on the frame arrangement with its main beams aligned with the smaller foot portions.
46. A frame arrangement substantially as hereinbefore described with reference to Figs. 1 and 3 of the accompanying drawings.
47. A frame arrangement substantially as hereinbefore described with

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reference to Fig. 2 of the accompanying drawings.
48. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating io the same invention as any of the preceding claims.