GB2376494A

GB2376494A - Frame arrangement for a ground surface access assembly

Info

Publication number: GB2376494A
Application number: GB0114452A
Authority: GB
Inventors: Barry Turner; David Edmonds
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: GB2376494B; GB0114452D0

Abstract

The frame arrangement, primarily for use with manhole covers, gully gratings etc., includes a support member 12 for mounting a cover member 14 and a flange 30 that extends outwards from a base of the support member, wherein the support member includes a wall upstanding from the general plane of the flange with at least part of the wall including a sloping portion 38 which slopes at an angle of between 15 and 75 degrees to the general plane of the flange. The flange is preferably generally planar and lies approximately parallel to a cover member mounted on the support member. The sloping portion preferably slopes outwardly from its top to its base and may be planar, convex or concave.

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 belowsurface installation. The frame may include an upstanding wall 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 member for mounting a cover member and a flange extending outwardly from a base of the support member, wherein the support member includes a wall upstanding from a general plane of the flange, at least a part of the wall including a sloping portion, which slopes at an angle of between 15'and 75'to the general plane of the flange.

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

Preferably the sloping portion of the wall slopes at an angle of between 30 and 60 , and most preferably about 40'to 50', to the general plane of the flange.

The wall may be generally rectangular in plan view, including side portions joined by curved corner portions.

Preferably the corner portions of the upstanding wall are substantially

perpendicular to the general plane of the flange. Preferably the wall is provided with an inwardly directed seat in each corner portion, for supporting a corner of the cover member. Preferably the part of the wall which includes a sloping portion embraces a mid-point of at least one side portion of the wall. Most preferably the sloping part extends an equal distance to each side of this midpoint. The sloping part may constitute between 50% and 75% of the length of the side portion.

A sloping part may embrace a mid part of each of the side portions of the wall. Alternatively the sloping part may extend along substantially the whole length of each side portion of the wall.

The sloping portion may extend the whole height of the part of the wall including that portion. Alternatively the slope may extend up a fraction of the height of the wall. Preferably a top portion of the upstanding wall is substantially perpendicular to the general plane of the flange, the sloping portion being provided below the top portion. The top portion may constitute between 5% and 40% of the height of the wall.

Preferably the top portion of the wall merges smoothly into a top of the sloping portion. Preferably a base of the sloping portion merges smoothly into the flange.

Preferably the sloping portion slopes outwardly from its top to its base.

The sloping part is preferably planar, but may be concave or convex.

An elongate bead may extend around an 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.

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 portions of the flange which extend outwardly from the corner portions of the wall.

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.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic perspective view of a manhole assembly including a frame arrangement according to the present invention mounting a cover member; Fig. 2 is a diagrammatic plan view of the manhole assembly of Fig. 1; Fig. 3 is a diagrammatic section on line A-A through the manhole

assembly of Fig. 2; Fig. 4 is a diagrammatic section on line B-B through the manhole assembly of Fig. 2; and Fig. 5 is a diagrammatic perspective view of the manhole frame of Fig. 1.

Referring to the drawings, a manhole assembly 10 includes a frame 12 and a cover member 14. The manhole assembly is of type D400, meaning that it is rated to take forces of up to 400kN.

Referring to Figs. 1 and 2, the cover member 14 of the manhole assembly 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.

The frame 12 is generally square in plan view, including straight side regions 22 and curved corner regions 24. Referring to Figs. 3 and 5 the frame 12 includes an upstanding wall 26 provided with seats 28 in the corner regions 24 of the frame 12. These seats 28 project inwardly from the wall 26 and support the corners of the cover member 14.

Extending outwardly from the base region of the upstanding wall 26 is a generally planar flange 30. The flange 30 has a smooth upper surface 32 and a lower surface 34 which is provided with smooth, protruding nodules 35 (see Figs. 3 and 4). At an outer edge of the flange 30, a generally circular crosssection bead 36 is provided.

The upstanding wall 26 is generally rectangular in plan view, including sides 37 joined by curved corners 39. At its corners 39, the wall 26 extends upwardly from the flange 30, generally perpendicular to the flange. Thus at its corners 39, the wall is approximately vertical when the manhole assembly is installed in a horizontal surface. Strengthening fillets 43 extend between the

corners 39 of the wall and the flange 30.

In central regions 41 of its sides 37, the upstanding wall 26 includes an upper, generally vertical portion 40, and a sloping portion 38. The sloping portion extends at an angle of about 45 from a lower end of the vertical portion 40 of the upstanding wall 26 and continues until it merges smoothly into the flange 30. In this region 22 the flange 30 is narrower than in the corner regions 24 of the frame 12.

The central regions 41 of the straight sides 22, which incorporate the sloping portions 38, make up between 50% and 75% of the lengths of the sides 37.

In use, the flange 30 is embedded in a mortar bed which holds the manhole assembly in place in the road. When a vehicle travels over the manhole assembly, a force is applied to the cover member 14, and hence to the frame 12 via the seats 28 in a downward direction. The Applicant has realised that the downward force applied to the flange 30 is essentially concentrated around the areas close to the seats 28.

Therefore the flange 30 does not need to be wide around the whole of the frame 12. Instead the present invention provides increased stability against vertical movement of the frame 12 as a vehicle passes over the manhole assembly 10, as explained below.

If the manhole frame is slightly proud of its surrounding surface, the top edge of the upstanding wall 26 nearest to the oncoming traffic is exposed to an impact force from the vehicle tyres. This force has a significant horizontal component. In a prior art manhole cover, having a generally"L"section frame, the base of the vertical upstanding wall 26 tends to act as a pivot point as the horizontal force is applied to the top of the wall. This causes the horizontal flange 30 to be subjected to a f6rce- which pivots it upwards, about the pivot point. This force thus tries to lift the flange and prize open its encapsulating

mortar. This is particularly damaging in the middle regions of the frame, remote from the corners, because the corners tend to stabilise the frame.

In the manhole frame according to the invention, the sloping wall 38 minimises the damaging pivotal movement discussed above. The horizontal force can be transmitted down the sloping wall, to exert a horizontal force (rather than a vertical force) on the flange 30. The flange 30 is bedded into the mortar in such a way that the mortar is well able to withstand such horizontal forces. Further, the lack of a clear pivot point, and the minimal width of the flange 30, means that any vertical forces applied to the flange are small.

As the force transmitted through to the flange 30 is reduced, the risk of a passing vehicle causing damage to the mortar bed (for example by causing cracks to appear) is reduced. This increases the effective lifetime of the manhole assembly 10.

Various modifications may be made without departing from the scope of the present invention. For example, there may be provided a number of short sloped sections along the length of the wall instead of one long sloped section.

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

1. A frame arrangement for a ground surface access assembly, the frame arrangement including a support member for mounting a cover member and a flange extending outwardly from a base of the support member, wherein the support member includes a wall upstanding from a general plane of the flange, at least a part of the wall including a sloping portion, which slopes at an angle of between 15 and 75 to the general plane of the flange.

2. A frame arrangement according to claim 1, wherein the flange is generally planar.

3. A frame arrangement according to claim 1 or claim 2, wherein the flange lies approximately parallel to a cover member mounted on the support member.

4. A frame arrangement according to any of the preceding claims, wherein the flange has a thickness of between 10mm and 20mm.

5. A frame arrangement according to any of the preceding claims, wherein the sloping portion of the wall slopes at an angle of between 30'and 60 to the general plane of the flange.

6. A frame arrangement according to claim 5, wherein the sloping portion of the wall slopes at an angle of between 40 and 50 to the general plane of the flange.

7. A frame arrangement according to any of the preceding claims, wherein the wall is generally rectangular in plan view, including side portions joined by curved corner portions.

8. A frame arrangement according to claim 7, wherein the corner portions of the upstanding wall are substantially perpendicular to the general plane of the flange.

9. A frame arrangement according to claim 7 or claim 8, wherein the wall is provided with an inwardly directed seat in each corner portion, for supporting a corner of the cover member.

10. A frame arrangement according to any of claims 7 to 9, wherein the part of the wall which includes a sloping portion embraces a mid-point of at least one side portion of the wall.

11. A frame arrangement according to claim 10, wherein the sloping part extends an equal distance to each side of this mid-point.

12. A frame arrangement according to claim 10 or claim 11, wherein the sloping part constitutes between 50% and 75% of the length of the side portion.

13. A frame arrangement according to any of claims 10 to claim 12, wherein the sloping part embraces a mid part of each of the side portions of the wall.

14. A frame arrangement according to any of claims 1 to 11, wherein the sloping part extends along substantially the whole length of each side portion of the wall.

15. A frame arrangement according to any of the preceding claims, wherein the sloping portion extends the whole height of the part of the wall including that portion.

16. A frame arrangement according to any of claims 1 to 14, wherein the slope extends up a fraction of the height of the wall.

17 A frame arrangement according to claim 16, wherein a top portion of the upstanding wall is substantially perpendicular to the general plane of the flange, the sloping portion being provided below the top portion.

18. A frame arrangement according to claim 17, wherein the top portion constitutes between 5% and 40% of the height of the wall.

19. A frame arrangement according to claim 17 or claim 18, wherein the top portion of the wall merges smoothly into a top of the sloping portion.

20. A frame arrangement according to any of claims 17 to 19, wherein a base of the sloping portion merges smoothly into the flange.

21. A frame arrangement according to claim 20 when dependent on claim 19, wherein the sloping portion slopes outwardly from its top to its base.

22. A frame arrangement according to any of the preceding claims, wherein the sloping part is planar.

23. A frame arrangement according to any of claims 1 to 21, wherein the sloping part is concave or convex.

24. A frame arrangement according to any of the preceding claims, wherein an elongate bead extends around an outer edge of the flange.

25. A frame arrangement according to claim 24, wherein the bead protrudes outwardly beyond an upper surface of the flange.

26. A frame arrangement according to claim 24 or claim 25, wherein the bead is of a smooth curved shape in section.

27. A frame arrangement according to claim 26, wherein the bead is substantially circular in section, having a radius of between 5mm and 20mm.

28. A frame arrangement according to claim 27, wherein the bead has a radius of about 10mm.

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 tA liame arra.. g, ^. , ^,", + are separated by smooth areas.

32. A frame arrangement according to claim 30 or claim 31, wherein areas of projections are provided on the undersurfaces of the portions of the flange which extend outwardly from the corner portions of the wall.

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 claim 29 when dependent on any of claims 24 to 28 or any of claims 30 to 33, wherein the projections merge smoothly into the bead.

35. A frame arrangement according to any of claims 29 to 34, wherein the projections have a smooth profile.

36. A frame arrangement according to any of claims 29 to 35, wherein the projections result in the profile of the undersurface having alternating peaks and troughs in each of any two mutually perpendicular directions.

37. A frame arrangement according to any of claims 29 to 36, 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.

38. A frame arrangement according to any of claims 29 to 37, wherein the projections have an undulating profile.

39. A frame arrangement according to claim 38, wherein the undulations are regular.

40. A frame arrangement according to claim 38, wherein the undulations are periodic.

41. A frame arrangement according to any of claims 32 to 40, wherein the undersurface of the flange is provided with a plurality of protruding nodules.

42. A frame arrangement according to claim 41, wherein the nodules protrude in a direction substantially perpendicular to the general plane of the undersurface of the flange.

43. A frame arrangement according to claim 41 or claim 42, wherein the nodules are substantially conical in shape, with blunt or curved peaks.

44. A frame arrangement according to claim 43, wherein the peaks of the nodules are between 5mm and 15mm apart.

45. A frame arrangement according to claim 43 or claim 44, wherein the peaks extend between 1.5mm and 5mm beyond the troughs.

46. A frame arrangement according to claim 45, wherein the peaks extend about 3mm beyond the troughs.

47. A frame arrangement substantially as hereinbefore described with reference to figures 1 to 5 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 to the same invention as any of the preceding claims.