GB2299603A

GB2299603A - Manhole cover

Info

Publication number: GB2299603A
Application number: GB9507141A
Authority: GB
Inventors: Barry Turner; David Henry Edmonds
Original assignee: C I S
Current assignee: C I S
Priority date: 1995-04-06
Filing date: 1995-04-06
Publication date: 1996-10-09
Anticipated expiration: 2015-04-06
Also published as: GB9507141D0; GB2299603B

Abstract

A manhole cover is formed from two cover parts 10, each having a substantially planar cover member 12 of triangular configuration which is reinforced on the underside by integral elongate beams 16, 24, 30, 34. The beam 16 is located towards one side of the cover member 12 and is effectively an I section, as are each of the beams 30, 34, while the beams 24 locate towards the other sides and are effectively of L section. The beam 30 extends between the beams 24 while the beam 34 extends between the beam 16 and the beam 30. The use of the beams increases the load bearing characteristics of the manhole cover and provides a more effective and predictable beam stress conveyance to a foundation in which the manhole is formed.

Description

Manhole Arrangements This invention relates to manhole arrangement and more particularly to manhole covers and their supporting frames.

Existing manhole covers are cast with anti-skid patterns on a top surface and reinforcing beams on the lower surface designed to transmit loading on the cover to the frame, and therefrom to the foundation in which the manhole is constructed. Roadway manhole covers and frames presently require to meet the relevant British Standard Load Classification and will soon require to meet a higher European Standard Load Classification.

According to the present invention there is provided apparatus for use as a manhole cover, the apparatus comprising a cover member for seating on a frame arrangement, and reinforcing means positioned on the cover member for providing the latter with desired load bearing characteristics, the reinforcing means comprising elongate members each connected along one side edge to one face of the cover member, the lower face in use, to extend from the latter, and at least one elongate member providing a load distribution flange on the opposed side edge thereof.

Preferably each of the elongate members provides a load distribution flange. Preferably also at least some of the flanges extend to each side of the respective elongate members to effectively form, with the cover member, load bearing beams substantially of I section.

Also, others of the flanges preferably extend to only one side of the respective elongate members to effectively form, with the cover member, load bearing flanges substantially of L section.

Apertures may be formed in the elongate members thereby to reduce the overall weight of the cover member.

The cover member may have a triangular configuration with an L section beam associated with each of two sides thereof, an I section beam associated with the other side of the cover member, and further I section beams optimally extending between the aforesaid beams.

Preferably means for mounting the cover member on the frame arrangement comprises profiled spigots for locating in complementary profiled recesses in the frame arrangement. The spigots may each have a tapering profile, whereby to function as a wedge, and the spigots may be provided at respective apices of the triangular configuration at the ends of respective beams.

Elongate projections may extend from the opposed face of the cover member, the upper face in use, at the locations of the elongate members.

Preferably the cover member is formed integrally with any or all of the elongate members, load distribution flanges, mounting spigots, and elongate projections, and may be formed as a metal casting.

A profiled opening may be formed through the cover member at the location of one of the elongate members, with an aperture being formed in the latter in communication with the opening, the latter being adapted to receive a profiled lifting tool for lifting of the cover member from the frame arrangement. An internal cover for the shaped aperture may be located in the elongate member aperture.

The invention also provides a manhole cover formed by a pair of apparatus as described in any of the eight preceding paragraphs, the cover members thereof being positioned with said other sides in abutment, and means provided for connecting the pair together.

The invention further provides a manhole arrangement comprising cover apparatus as described in any of the nine preceding paragraphs, and a frame arrangement optimally profiled to provide required material at locations where load is dissipated to a foundation, and sufficient material at locations required for fixing to the medium of the foundation.

Preferably the material is principally provided at corners of the frame arrangement, and support members may be provided for the corner material.

An embodiment of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a top plan of a manhole cover within a supporting frame; Fig. 2 is an underneath plan of one of the manhole cover parts of Fig. 1; Fig. 3 shows the cover part of Fig. 2 in elevation in the direction of arrow A; Fig. 4 is a cross-section on X-X of Fig. 2; and Fig. 5 is a cross-section on Y-Y of Fig. 2.

Referring to Figs. 2 to 5 of the drawings, a manhole cover part 10 is formed of a cast metal and comprises a substantially planar cover member 12 having a triangular configuration. At each apex, a profiled spigot 14 extends downwardly from the lower surface of the cover member 12, each spigot 14 having a tapering profile to act as a wedge when the cover member 12 is seated in a supporting frame as hereinafter described.

The cover member 12 is reinforced by a configuration of elongate beams on the underside thereof. A first beam 16 has the form of an elongate web 18 integrally cast along one side edge thereof on the cover member 12, with the other side edge providing a flange 20 extending to either side of the web 18. The latter and the flange 20 effectively form with the cover member 12, a supporting beam of I section. The web 18 reduces in width from a central part 22 towards each end where the beam meets with the respective spigot 14. As shown in Fig. 2, the beam 16 also is angled inwardly of the associated side of the cover member 12 from the respective spigot 14 to the central part 22.

At a location towards, and extending parallel to, each of the other sides of the cover member 12, a further beam 24 has a web 26 cast with one side edge on the underside of the cover member 12, with the other side edge mounting a flange 28 which extends only to the inner side of the web 26. The latter and the flange 28 effectively form, with the cover member 12, a beam of L section. Each beam 24 extends between a respective pair of the spigots 14.

In an optimal arrangement which minimises the length of beams to be used, whilst maximising the load capabilities of the manhole cover, a further beam 30 of I section extends at right angles from each of the beams 24 at a location intermediate the respective ends thereof, and has an arcuate part 32. A further I beam 34 extends between the arcuate part 32 and the central part 22 of the beam 16. The beam 30 provides a web 36 integral with a web 38 of the beam 34, the latter being integral with the web 18 of the beam 16. Similarly a flange 40 of the beam 30 is integral with a flange 42 of the beam 34, the latter being integral with the flange 20 of the beam 16.

The cover member 12 is cast with elongate projections 46 (Fig. 1) on the upper face thereof and extending immediately above each of the beams. To reduce the amount of material used, and therefore the weight of the cover part 10, material is removed from areas selected as hereinafter described, a series of through apertures 44 (Fig. 3) being thereby provided on each beam, the apertures 44 in the beam 16 reducing in size from the central part 22 towards each respective end.

Referring to Fig. 1, a frame 50 is designed to define the upper end of a manhole and provides a seating for a manhole cover 52 formed of two cover parts 10 located with their longer sides in abutment. The frame 50 provides a downwardly tapering recess at each of opposed corners 54, 56 for receiving respective ones of the spigots 14, and a pair of such recesses at each of the other corners 58, 60 for receiving a respective pair of the spigots 14.

The frame 50 has a peripheral, outwardly extending flange 62 which keys the supporting frame to the fixing medium of the foundation in which the manhole is formed.

The flange 62 is so profiled as to avoid using material in areas which do not effectively contribute to dissipation of the loading on the manhole cover and frame to the foundation, but retains sufficient material at the corners 54-60, a pair of supporting fillets 64 being provided at each corner in order to concentrate material in highly stressed zones. Between each pair of corners, an area 66 is formed of material for keying purposes, with a supporting fillet 68 being provided at each of the areas 66.

The cover parts 10 are secured together by suitable fixings through aligned holes 70 in the web 18 of each of the beams 16.

The use of reinforcing beams of I and L section lowers the stress in the material most remote from the point of loading, and therefore reduces the likelihood of progressive work-hardening. Whilst the use of such beams increases the load bearing characteristics sufficient to achieve the European Load Standard Classification, weight is reduced by removing materia i.e. forming the through apertures 44, in areas of the beams not critical to load conveyance from the cover members 12 to the beam flanges. While the design retains all the benefits of existing designs, and meets increased load classification, there is a more effective and predictable beam stress conveyance to the foundation, together with lighter cover parts and supporting frame.The extensions of the beam locations onto the upper side of the covered parts, gains added deflection benefits, while also providing a functional anti-skid pattern. Additional anti-skid patterns may be formed between the respective upper side extensions.

For lift out of the cover parts 10, each is provided with a keyway 72 in the form of a profiled through opening in the cover member 12 at a location above the beam 34. A corresponding aperture is formed in the upper surface of the beam 34 whereby to enable a key to be inserted through the keyway 72 and moved through ninety degrees in that beam aperture in a conventional way, to form a lifting tool. A semi-flexible plastics cover (not shown, may be pushed through the beam aperture to locate therein below the keyway 72.

Various modifications may be made without departing from the invention and yet still maintain the advantages as hereinbefore described. For example, the configurations of the reinforcing beams may differ from those descibed and shown, while the extensions of the beam locations on the upper side of the cover parts may be omitted. Also, the position of the keyways for the lifting tools may differ from those described and shown.

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

aaims:-

1. Apparatus for use as a manhole cover, the apparatus comprising a cover member for seating on a frame arrangement, and reinforcing means positioned on the cover member for providing the latter with desired load bearing characteristics, the reinforcing means comprising elongate members each connected along one side edge to one face of the cover member, the lower face in use, to extend from the latter, and at least one elongate member providing a load distribution flange on the opposed side edge thereof.

2. Apparatus according to Claim 1, wherein each of the elongate members provides a load distribution flange.

3. Apparatus according to Claim 2, wherein at least some of the flanges extend to each side of the respective elongate members to effectively form, with the cover member, load bearing beams substantially of I section.

4. Apparatus according to Claim 3, wherein others of the flanges extend to only one side of the respective elongate members to form load bearing beams substantially of L section.

Apparatus according to Claim 4, wherein the cover member has a triangular configuration with an L section beam associated with each of two sides thereof, an I section beam associated with the other side of the cover member, and further I section beams optimally provided by flanges extending between the aforesaid I section beam and the L section beams.

6. Apparatus according to any of the preceding Claims, wherein apertures are formed in at least one of the elongate members thereby to reduce the overall weight of the cover member.

7. Apparatus according to any of the preceding Claims, wherein means for mounting the cover member on the frame arrangement comprises profiled spigots for locating in complementary profiled recesses in the frame arrangement.

8. Apparatus according to Claim 8, wherein the spigots each have a tapering profile, whereby to function as a wedge, and the spigots are provided at respective apices of the triangular configuration at the ends of respective elongate members.

9. Apparatus according to any of the preceding Claims, wherein elongate projections extend from the opposed face of the cover member, the upper face in use, at the locations of the elongate members.

10. Apparatus according to Claim 9, when dependent on Claim 7 or 8, wherein the cover member is formed integrally with the elongate members, the or each load distribution flange, the mounting spigots, and the elongate projections.

11. Apparatus according to Claim 10, wherein the cover member is formed as a metal casting.

12. Apparatus according to any of the preceding Claims, wherein a profiled opening is formed through the cover member at the location of one of the elongate members, with an aperture being formed in the latter in communication with the opening, the latter being adapted to receive a profiled lifting tool for lifting of the cover member from the frame arrangement.

13. Apparatus according to Claim 12, wherein an internal cover for the shaped aperture is located in the elongate member aperture.

14. A manhole cover formed by a pair of apparatus according to any of the preceding Claims, the cover members thereof being positioned with said other sides in abutment, and means provided for connecting the pair together.

15. A manhole arrangement comprising a manhole cover according to Claim 14, and a frame arrangement optimally profiled to provide required material at locations where load is dissipated to a foundation, and sufficient material at locations required for fixing to the medium of the foundation.

16. An arrangement according to Claim 15, wherein the material is principally provided at corners of the frame arrangement, and support members are provided for the corner material.

17. Apparatus for use as a manhole cover, substantially as hereinbefore described with reference to the accompanying drawings.

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

19. A manhole arrangement substantially as hereinbefore described with reference to the accompanying drawings.

20. 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.