Technical Field

The present invention relates to ground surface access assemblies.

Background

Conventionally, ground surface access assemblies comprise a frame defining an opening and one or more covers which locate onto the frame in or above the opening. The or one or each cover is openable or removable to permit access to underground services via the opening. Traditionally, during installation, the frame is laid on a bed of bedding material such as mortar on top of a chamber structure formed of concrete or brick. Surround material (which could comprise underlying foundation material, bedding material, haunching material, sub base material, road base material and surfacing material) is then installed up to ground surface level, substantially to the top of the frame, so that the sides of the frame are fully covered.

Investigations have shown that nowadays, for a variety of reasons (primarily the increased use of ductile iron), it is more often installation failure which occurs rather than failure of the covers and frame. In installation failure, the access assembly remains intact and functional, but the surround material degrades and breaks up. This in itself can present a hazard to road users. Furthermore this can result in the access assembly becoming loose and dislodged, presenting a further hazard to road users.

In this specification, the terms inner, outer, inwardly and outwardly, when used in relation to the frame, are used with respect to the opening, which is inward of the frame, and the terms upward and downward are used in relation to the in use orientation of a ground surface access assembly, in which downward means down into the ground. In this specification, the term cover has been used to mean solid and/or gridded covers (gratings).

Statements of Invention

According to a first aspect of the present invention, there is provided a ground surface access assembly frame for cooperation with an upper part of a chamber structure, the frame defining an opening and including a mounting for a cover, which is arranged so that, in use, the cover locates in the opening, wherein, in an assembled condition, the frame locates on and is supported by the upper chamber part.

According to a second aspect of the present invention, there is provided an upper part of a chamber structure for cooperation with a ground surface access assembly frame, the frame defining an opening and including a mounting for a cover, which is arranged so that, in use, the cover locates in the opening, wherein, in an assembled condition, the frame locates on and is supported by the upper chamber part.

According to a third aspect of the present invention, there is provided a ground surface access assembly, the assembly including a frame defining an opening, the frame including a mounting for a cover, which is arranged so that, in use, the cover locates in the opening, the assembly including an upper part of a chamber structure, wherein, in an assembled condition, the frame locates on and is supported by the upper chamber part.

Possibly, in the assembled condition, the frame is only supported by the upper chamber part.

Possibly, in the assembled condition, the frame does not extend outwardly beyond an outward extremity of the upper chamber part. Possibly, in the assembled condition, the frame directly contacts the upper chamber part, with no intermediate material therebetween.

Possibly, the frame includes a seating surface. Possibly, the upper chamber part includes a mounting surface. Possibly, in the assembled condition, the frame seating surface locates directly on the mounting surface of the upper chamber part with no intermediate material therebetween.

Possibly, the frame and the upper chamber part each include a mutually cooperating interlock feature, which, in use and in the assembled condition, interlock to resist lateral (side to side) relative movement between the frame and the upper chamber part.

The interlock features may be a sliding fit together and may be an interference fit together. One of the interlock features may be tapered in cross section profile to provide the interference fit.

Possibly, one of the interlock features includes a projection and one of the features defines a recess in which, in the assembled condition, the projection locates to provide the interlock.

Possibly, the upper chamber part interlock feature defines the recess and the frame interlock feature includes the projection.

Possibly, the interlock feature projection defines one or more apertures, which may be through apertures.

Possibly, the interlock feature projection reduces in cross-sectional width, and may be stepped, and may comprise a plurality of parts which are progressively narrower in width. Possibly, the interlock feature projection comprises three parts. Possibly, the interlock feature projection comprises a step between each part. Possibly, the upper chamber part includes outer side wall surfaces. Possibly, the frame includes outer side wall surfaces. Possibly, in the assembled condition, the upper chamber part outer side wall surfaces and the frame outer side wall surfaces are substantially aligned, possibly substantially vertically.

Possibly, in the assembled condition, no part of the frame projects laterally outwardly beyond the outer side wall surfaces of the upper chamber part.

Possibly, the frame includes one or more side members. Possibly, each side member includes an upstanding frame side wall. Each frame side wall may include one of the outer frame side wall surfaces. Possibly, each frame side wall includes an inner frame side wall surface.

Possibly, each side member includes a base wall. The or some or each base wall may comprise a flange part. Possibly, each flange part projects inwardly from a lowermost part of one of the frame side walls.

Possibly, no part of the base wall or the flange part projects outwardly (ie away from the opening) from any of the side walls.

Possibly, the frame seating surface comprises an in-use downwardly directed surface of the base wall.

Possibly, the frame interlock projection projects downwardly from the base wall and may project downwardly from the frame seating surface.

Possibly, the frame seating surface includes an outer portion which is located adjacent to an outer side of the frame interlock projection and may include an inner portion which is located adjacent to an inner side of the frame interlock projection. Possibly, the frame seating surface includes both the outer portion and the inner portion. Possibly, the or one or each portion is in the form of a strip, which may extend continuously around the opening.

Possibly, the frame interlock projections extend longitudinally along the base wall. Each frame interlock projection may be in the form of a fin or rib. Possibly, each base wall has one frame interlock projection projecting therefrom.

Possibly, the frame interlock projections are intermittent and spaced apart and may be in the in the form of studs, pegs, nodules or the like. Possibly, each base wall has a plurality of frame interlock projections projecting therefrom, which may be aligned in a row.

Possibly, the upper chamber part defines a plurality of the interlock recesses which may correspond in number to the number of frame interlock projections, and may correspond in shape.

Possibly, the or one or each interlock recess receives, in the assembled condition, a plurality of the frame interlock projections.

Possibly, the upper chamber part includes one or more chamber side walls. Possibly, each side wall includes an upwardly directed chamber side wall upper surface. Possibly, the chamber side wall upper surfaces comprise the mounting surface.

Possibly, the or one or some or each of the chamber side wall upper surfaces define the or one or more of the interlock recesses.

Possibly, the or one or each interlock recess extends longitudinally along one or more of the chamber side wall upper surfaces. Possibly, the or one or some or each interlock recess is in the form of a slot or channel. Possibly, in the assembled condition, the assembly includes fixing material which is located between the frame interlock projection and the chamber part. The fixing material may be a settable material which is movable between a relatively fluid condition, in which the fixing material can flow between the frame interlock projection and the upper chamber part, and a relatively solid condition, in which the fixing material substantially does not flow but is substantially solid.

Possibly, in the assembled condition, the fixing material substantially fills spaces defined in the recess between the frame interlock projection and the chamber part.

Possibly, the fixing material is a cementitious material, a polymer modified cementitious material, an epoxy grout or the like.

Possibly, the assembly includes an adjustor, for adjusting the height of the frame relative to a fixed chamber structure. Possibly, the fixed chamber structure is that part of the chamber structure on which the ground surface access assembly is installed in use.

Possibly, the assembly is movable from an adjustment condition, in which the adjustor is operable to adjust the height of the frame, to a fixed condition, in which the frame height is fixed.

Possibly, the adjustor comprises part of the frame and may comprise at least one adjustor member, which may be threaded, and which may extend through a threaded adjustor hole, which may be defined by the frame base wall.

Possibly, the adjustor member extends downwardly, possibly substantially vertically, into the chamber interlock recess, possibly to a chamber recess base wall, which may define the recess and may comprise part of the upper chamber part. Possibly, in the adjustment condition, the adjustor member is operable by rotation to adjust the relative height of the frame.

The frame base wall may define a plurality of the adjustor holes and the adjustor may comprise a plurality of the adjustor members. The adjustor holes may be arranged in pairs, with one pair being defined by one, some or each frame base wall.

Possibly, in the fixed condition, the adjustor member is fixed to prevent to rotation.

Possibly, the adjustor includes a first adjustor chamber member and a second adjustor chamber member, each of which may comprise part of the upper chamber part, and which, in the adjustment condition, may movably inter- engage to permit adjustment of the height of the frame relative to the fixed chamber structure.

Possibly, in the adjustment condition the first adjustor chamber member is movable relative to the second adjustor chamber member.

Possibly, the first and second adjustor chamber members each include a mutually cooperating adjustment feature, which, in the assembled condition, may permit adjustment of the height of the frame.

Possibly, one of the adjustment features includes an adjustment projection and one of the adjustment features defines an adjustment recess in which, in the assembled condition, the adjustment projection may locate.

Possibly, the first adjustor chamber member includes the interlock feature of the upper chamber part, and may define, at an upper end, the interlock recess(es). Possibly, the first adjustor chamber member includes the adjustment projection, which may extend downwardly, which, in the assembled condition, may be received in the adjustment recess, which may be defined by the second adjustor chamber member.

Possibly, in the fixed condition, the first adjustor chamber member is fixed relative to the second adjustor chamber member. Possibly, the adjustor includes a locking device for locking the assembly in the fixed condition.

Possibly, the locking device includes a locking member which extends, possibly substantially horizontally, through locking holes defined in the first and second adjustor chamber members. The locking device may include a plurality of locking members. Some or all of the locking holes may be pre-formed, possibly during manufacture, or possibly prior to installation. Some or all of the holes may be formed in situ. Some locking holes may be pre-formed and some may be formed in situ. Some of the holes may be elongate and may be in the form of slots, which may have a longitudinal axis which may be aligned substantially vertically.

Possibly, the adjustor includes adjustor fixing material which is located between the adjustment projection of the first adjustor chamber member and the second adjustor chamber member. The adjustor fixing material may be a settable material which is movable between a relatively fluid condition, in which the adjustor fixing material can flow, and a relatively solid condition, in which the fixing material substantially does not flow but is substantially solid.

Possibly, in the assembled condition, the adjustor fixing material substantially fills spaces defined in the adjustment recess between the adjustment projection of the first adjustor chamber member and the second adjustor chamber member.

Possibly, the adjustor fixing material comprises a cementitious material, a polymer modified cementitious material, an epoxy grout or the like. The adjustor may include one or more packing members. Possibly, the or each packing member is located between the frame and the upper chamber part.

Possibly, the or each packing member is located between the adjustment features, and may be located between the adjustment projection of the first adjustor chamber member and the second adjustor chamber member. Possibly, the or each packing member comprises the locking device.

Possibly, the frame includes mounting projections, which may project inwardly from the side wall, for mounting the cover. Possibly, the mounting projections are spaced upwardly from the base walls and/or the flange part.

Possibly, the ground surface access assembly includes a plurality of covers. Possibly, the or each cover is mounted so that it contacts the frame at three points, to provide non-rock mounting.

Possibly, the upper chamber part defines a passage which communicates with the opening.

Possibly, the frame is formed of a metallic material and may be formed by casting. Possibly, the frame is formed of cast iron, possibly, ductile iron.

Possibly, the or each cover is formed of a metallic material and may be formed by casting. Possibly, the or each cover is formed of cast iron, possibly, ductile iron.

Possibly, the upper chamber part is formed of concrete and/or resin.

According to a fourth aspect of the present invention, there is provided a method of providing access to underground services, the method including providing a ground surface access assembly, the assembly including a frame defining an opening, the frame including a mounting for a cover, which is arranged so that, in use, the cover locates in the opening, the assembly including an upper part of a chamber structure, wherein, in an assembled condition, the frame locates on and is supported by the upper chamber part.

Possibly, the assembly includes any of the features described in any of the preceding statements or following description. Possibly, the method includes any of the steps described in any of the preceding statements or following description.

Figures

Embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:-

Fig. 1 is a plan view of a prior art ground surface access assembly;

Fig. 2 is a side cross sectional view of a part of the prior art ground surface access assembly of Fig. 1 in an installed condition;

Fig. 3 is a side cross sectional view of a part of a first embodiment of a ground surface access assembly according to the invention in the installed condition;

Fig. 4 is a relatively enlarged, slightly exploded detail taken from Fig. 3 as indicated by the part label IV;

Fig. 5 is a cross sectional side view of a portion of the part of the first embodiment as indicated by the section line and arrows V in Fig. 3;

Fig. 6 is a cross sectional side view similar to that of Fig. 5, but somewhat exploded for clarity, of a part of a second embodiment of a ground surface access assembly according to the invention;

Fig. 7 is a side cross sectional view of a part of a third embodiment of a ground surface access assembly according to the invention in the installed condition;

Fig. 8 is a side cross sectional view of a part of a fourth embodiment of a ground surface access assembly according to the invention in the installed condition; Fig. 9 is a side cross sectional view of a part of a fifth embodiment of a ground surface access assembly according to the invention;

Fig. 10 is a side cross sectional view of a part of a sixth embodiment of a ground surface access assembly according to the invention;

Fig. 11 is a side view of a frame only of a seventh embodiment of a ground surface access assembly according to the invention; and

Fig. 12 is a side cross-sectional view of a frame only of an eighth embodiment of a ground surface access assembly according to the invention.

In the drawings, where multiple instances of the same or similar features exist, only a representative one or some of the instances of the features have been provided with numeric references for clarity.

Description: Prior Art

Figs. 1 and 2 show a prior art ground surface access assembly 10. The assembly 10 includes a frame 12 defining an opening 14. The frame 12 includes a mounting 16 for a cover 18, which is arranged so that, in use, the cover 18 locates in the opening 14.

In the example shown, the frame 12 includes four side members 94. Each side member 94 includes an upstanding side wall 40. Each side wall 40 includes an outer side wall surface 38 and an inner side wall surface 42.

Each side member 94 includes a base wall 44. Each base wall 44 includes a flange part 90, which projects outwardly from a lowermost part of one or more of the side walls 40.

In the example shown, the ground surface access assembly 10 includes a pair of covers 18. The mounting 16 includes mounting projections 17, which project inwardly from the side walls 40, for mounting the cover 18. The mounting projections 17 are spaced upwardly from the base walls 44.

In the example shown, each cover 18 is mounted so that it contacts the frame 12 at three points, to provide non-rock mounting.

Typically, the frame 12 and the covers 18 are formed by casting of cast iron, which could be ductile iron.

Fig. 2 shows the prior art ground surface access assembly 10 in an installed condition. The frame 12 is laid on a layer 88 of bedding material 78 (such as mortar) on top of an upper part 22 of a chamber structure 80, which defines a passage 24 which communicates with the opening 14. The chamber structure 80 could be formed of concrete or brick. The upper chamber part 22 includes outer side wall surfaces 36. Surround material 82 (which could comprise underlying foundation material, bedding material, haunching material, sub base material, road base material and surfacing material) is then installed up to ground surface level 84, substantially to the top of the frame 12.

The outwardly extending base walls 44 extend laterally outwardly beyond the outer side wall surfaces 36 of the upper chamber part 22. This provides the advantage that the span distances between the mounting projections 34 for the covers 18 are minimised, which assists in reducing product weight. However, the Applicant has realised that, in practice, this arrangement causes a number of disadvantages.

In one failure mode, in use, under traffic loads, vertical loads (arrows Fv, Fig. 2) are applied to the covers 18 which cause flexing of the frame 12. This in turn results in a relatively high load concentration on the inward edge of the bedding material layer 88, which over time can degrade and fall into the passage 24. The loss of the bedding material layer 88 can result in the frame 12 dropping (arrow D), leading to a void forming above the flange part 90. Further trafficking can then cause failure of the surround material 82 above the flange part 90. Flexing of the frame 12 under traffic loading also causes movement of the base walls 44 projecting beyond the upper chamber part 22 which causes degradation of the surround material 82.

In another failure mode, in use, braking forces apply horizontal lateral loads (arrow FH, Fig. 2) to the covers 18 and the frame 12, resulting in horizontally extending shear stress planes being formed in the bedding layer 88, between the bedding layer 88 and the frame 12 and between the bedding layer 88 and the upper chamber part 22. The stress planes can cause failure planes resulting in lateral movement of the frame 12 relative to the upper chamber part 22 (arrow L).

In another failure mode, loading on the surround material 82 (for example, by road surfacing machinery) can be transmitted through the surround material 82 to dislodge or distort the chamber upper part 22 of the chamber structure (arrows FR).

Description: Embodiments of the Invention

Figs. 3 to 5 show a first embodiment of a ground surface access assembly 1 10 according to the invention, many features of which are similar to those already described in relation to the prior art arrangement of Figs 1 and 2. Therefore, for the sake of brevity, the following embodiment will only be described in so far as it differs from the arrangement already described. Where features are the same or similar, the same reference numerals have been used and the features will not be described again.

The assembly 1 10 includes a frame 1 12 defining an opening 14. The frame 1 12 includes a mounting 16 for a cover 18, which is arranged so that, in use, the cover 18 locates in the opening 14. The assembly 1 10 includes an upper chamber part 122 of a chamber structure 80, wherein, in an assembled condition, the frame 1 12 locates on and is supported by the upper chamber part 122.

The frame 1 12 and the covers 18 could be formed by casting of cast iron, which could be ductile iron.

The upper chamber part 122 could be formed of concrete and/or resin.

The frame 1 12 includes a seating surface 20. The upper chamber part 122 includes a mounting surface 26.

The upper chamber part 122 defines a passage 24 which communicates with the opening 14.

The frame 1 12 and the upper chamber part 122 each include a mutually cooperating interlock feature 28, 30 respectively, which, in use and in the assembled condition, interlock to resist lateral (side to side) relative movement between the frame and the upper chamber part.

One of the interlock features 28, 30 includes a projection 34 and one of the interlock features 28, 30 defines a recess 32 in which, in the assembled condition, the projection 34 locates.

In the example shown, the frame interlock feature 28 comprises the projection 34 and the upper chamber part interlock feature 30 defines the recess 32.

As seen most clearly in Fig. 4, in one example, the projection 34 is tapered in cross section profile and the recess is correspondingly shaped. In one example, the projection 34 could be a sliding fit in the recess 32. In another example, the projection could be an interference fit in the recess 32. The upper chamber part 122 includes outer side wall surfaces 36. The frame 1 12 includes outer side wall surfaces 38. In the assembled condition, the upper chamber part outer side wall surfaces 38 and the frame outer side wall surfaces 36 are substantially vertically aligned.

The frame 1 12 includes one or more side members 194. In the example shown, the frame 1 12 includes four side members 194. Each side member 194 includes an upstanding side wall 40. Each frame side wall 40 includes one of the outer side wall surfaces 38 and an inner side wall surface 42.

Each side member 194 includes a base wall 144, which comprises a flange part 92. Each flange part 92 projects inwardly from a lowermost part of one of the side walls 40.

No part of the base walls 144 or the flange parts 92 projects outwardly (ie away from the opening) from any of the side walls 40.

The frame seating surface 20 comprises in-use a downwardly directed surface of the base wall 144.

The frame interlock projection 34 projects downwardly from the base wall 144 and from the frame seating surface 20.

The mounting 16 includes mounting projections 17, which project inwardly from the side walls 40, for mounting the cover 18. The mounting projections 17 are spaced upwardly from, and on the same inward side of the side walls 40 as, the base walls 144. Each mounting projection 17 is in the form of a projecting ledge 76.

In the example shown, the frame seating surface 20 includes both an outer portion 46, which is located adjacent to an outer side of the frame interlock projection 34, and an inner portion 48 which is located adjacent to an inner side of the frame interlock projection 34. Each portion 46, 48 is in the form of a strip. In one example, each portion 46, 48 extends continuously around the opening 14.

In the example shown in Figs. 3, 4 and 5, the frame interlock projections 34 extend longitudinally along the base wall 144. Each frame interlock projection 34 could be in the form of a fin, rib or blade.

In one example, each base wall 144 has one frame interlock projection 34 projecting therefrom.

The upper chamber part 122 includes four chamber side walls 96. Each side wall 96 includes an upwardly directed chamber side wall upper surface 98. The chamber side wall upper surfaces 98 comprise the mounting surface 26.

In the example shown in Figs. 3, 4 and 5, each chamber side wall upper surface 98 defines one of the interlock recesses 32. Each interlock recess 32 extends longitudinally along the respective chamber side wall upper surface 98. Each interlock recess 32 is in the form of a slot or channel.

In the assembled condition, the assembly 1 10 includes fixing material 50 which is located between the frame interlock projection 34 and the upper chamber part 122. The fixing material 50 is a settable material which is movable between a relatively fluid condition, in which the fixing material 50 can flow between the frame interlock projection 34 and the upper chamber part 122, and a relatively solid condition, in which the fixing material 50 substantially does not flow but is substantially solid.

In use, the frame 1 12 is located on to the upper chamber part 122 so that the frame 1 12 directly contacts the upper chamber part 122. In the assembled condition, the frame seating surface 20 locates directly on the mounting surface 26 of the upper chamber part 122 with no intermediate material therebetween. The frame 1 12 does not extend outwardly beyond an outward extremity of the upper chamber part 122. No part of the frame 1 12 projects laterally outwardly beyond the outer side wall surfaces 38 of the upper chamber part 122.

In the assembled condition, the frame interlock projections 34 locate in the chamber interlock recesses 32. The fixing material 50, which could be a cementitious material, a polymer modified cementitious material, an epoxy grout or the like, is located between the frame interlock projection 34 and the upper chamber part 122 so that it substantially fills spaces 52 defined in the recess 30 between the frame interlock projection 34 and the upper chamber part 122. The fixing material 50 could be located before and/or after location of the frame 1 12 on to the upper chamber part 122.

With the frame 1 12 in the assembled condition on the upper chamber part 122, the surround material 82 is located against the side walls 96 of the upper chamber part 122 and the frame side walls 40 up to the ground surface level 84.

It is a feature of the invention that, in the assembled condition, the frame 1 12 is in direct contact with the upper chamber part 122, with no intermediate layer of relatively weak bedding material 78 therebetween. Advantageously, flexing of the frame 1 12 under traffic loading does not transmit movement to layer 88 of the intermediate bedding material 78, which in conventional arrangements can result in the formation of horizontal planes of weakness in the relatively weak intermediate material, which can in turn result in lateral movement between the frame 1 12 and the upper chamber part 122, loss of the bedding material 78, dropping of the frame and degradation of the surround material 82.

It is a feature of the invention that, in the assembled condition, the frame 1 12 is only vertically supported by the upper chamber part 122, which permits the frame 1 12 to move separately relative to the surround material 82. Advantageously, flexing of the frame 1 12 under traffic loading does not transmit movement to the surround material 82 via a projecting flange which, in conventional arrangements, can result in degradation of the surround material 82.

The mutually cooperating interlock features 28, 30 of the frame 1 12 and the upper chamber part 122 interlock to resist lateral (side to side) relative movement between the frame 1 12 and the upper chamber part 122, reducing the risk of installation failure due to the transmission of lateral forces to and from the surround material 82.

The mutually cooperating interlock features 28, 30 are shown in cross section in Figs. 3 and 4 and could take a number of differing forms in longitudinal shape. As mentioned above, one example has been shown and described in Fig. 5. In this example, the interlock features 28, 30 could extend the whole length or the majority of the whole length of each side wall 96 of the upper chamber part 122 and each frame side member 194, so that each frame side member 194 has one frame interlock projection 34 projecting downwardly therefrom and each chamber side wall 96 defines one chamber interlock recess 32.

In a second embodiment of the invention, an assembly 210, shown in Fig. 6, a plurality of interlock features 28, 30 are intermittent along the length of each side wall 96 of the upper chamber part 122 and each frame side member 194. Each frame side member 194 includes a plurality of frame interlock projections 34 projecting downwardly therefrom, which are aligned in a row. The frame interlock projections 34 are intermittent and spaced apart and could be in the in the form of studs, pegs, nodules or the like.

Each chamber side wall 96 defines a plurality of interlock recesses 32, which correspond in number to the number of the frame interlock projections 34, and correspond in shape. Advantageously, the interlock features 28, 30 of Fig. 6 provide lateral interlock in two mutually horizontal orthogonal directions (eg X-Y).

The Applicant has further realised that the interlocking features 28, 30 could be provided on one, some or all of the sides of the frame 1 12 and the upper chamber part 122. For example, in the case of gully gratings which are commonly located against a kerb at the side of a road, the interlocking features 28, 30 might only be provided on the three sides subjected to traffic in the roadway.

In another example (not shown), one or the or each interlock recess 32 could receive, in the assembled condition, a plurality of the frame interlock projections 34.

Other Embodiments

Figs. 7 to 12 show other embodiments of the invention, many features of which are similar to those already described in relation to the embodiments of Figs 3 to 6. Therefore, for the sake of brevity, the following embodiments will only be described in so far as they differ from the embodiments already described. Where features are the same or similar, the same reference numerals have been used and the features will not be described again.

Fig. 7 shows a third embodiment, a ground surface access assembly 310. The assembly 310 includes an adjustor 54, for adjusting the height of the frame 1 12 relative to a fixed chamber structure 86. The fixed chamber structure 86 is that part of the chamber structure on which the ground surface access assembly 310 is installed in use.

The assembly 310 is movable from an adjustment condition, in which the adjustor 54 is operable to adjust the height of the frame 1 12, to a fixed condition, in which the height of the frame 1 12 is fixed. The adjustor 54 comprises part of the frame 112 and comprises at least one adjustor member 56. In the example shown, the adjustor member 56 is threaded, and extends through a threaded adjuster hole 58 (shown in dashed lines in Fig. 7) defined by the frame base wall 144. The adjustor member 56 extends downwardly, substantially vertically in use, and alongside the frame interlock projection 34 to a chamber recess base wall 60, which comprises part of the upper chamber part 122 and defines the chamber interlock recess 32.

The frame base walls 144 could define a plurality of the adjustor holes 58 and the adjustor 54 could comprise a plurality of the adjuster members 56. The adjustor holes 58 could be arranged in one or more pairs, with one pair being defined by one, some or each frame base wall 144. Each of the adjuster holes 58 could be located in the vicinity of or towards one of the corners of the frame 112.

In use, the frame 112 is located on to the upper chamber part 122 so that the frame 112 directly contacts the upper chamber part 122 with no intermediate material therebetween. The frame interlock projections 34 locate in the chamber interlock recesses 32.

The adjustor members 56 are then located through the adjustor holes 58 and, in the adjustment condition, are adjusted by rotation until the adjustor members 56 contact the chamber recess base wall 60 and the frame 112 is at the required height relative to the finished ground surface level 84.

The adjustor members 56 could be fixed at this position by the use of, for example, thread locking adhesive, locknuts etc. which prevent rotation of the adjustor members 56.

At the required height, the frame 112 could contact the upper chamber part 122 via the frame seating surfaces 20, one or some of the adjustor members 56, or a combination thereof. The fixing material 50 is then located in the space 52 and allowed to set, fixing the frame 1 12 in the fixed condition at the required height above the fixed chamber structure 86.

The surround material 82 is then located against the side walls 96 of the upper chamber part 122 and the frame side walls 40 up to the ground surface level 84. In this embodiment, it is an advantage for the frame interlock projections 34 to extend substantially continuously along the side members 194, to act as a barrier or shuttering for the surround material 82.

Fig. 8 shows a fourth embodiment, a ground surface access assembly 410. In this embodiment, the adjustor 54 includes first and second adjustor chamber members 62, 66 respectively, which together comprise the upper chamber part 122.

In the adjustment condition, the first adjustor chamber member 62 and the second adjustor chamber member 66 movably inter-engage to permit adjustment of the height of the frame 1 12 relative to the fixed chamber structure 86. In the adjustment condition, the first adjustor chamber member 62 is movable relative to the second adjustor chamber member 66.

The first and second adjustor chamber members 62, 66 each include a mutually cooperating adjustment feature 102, 104 respectively, which, in the assembled condition, permits adjustment of the height of the frame 1 12.

One of the adjustment features 102, 104 includes a projection 64 and one of the adjustment features 102, 104 defines an adjustment recess 68 in which, in the assembled condition, the projection 64 locates.

The first adjustor chamber member 62 includes the interlock feature 30 of the upper chamber part 122. In the example shown, the first adjustor chamber member 62 defines, at an upper end, the interlock recess(es) 32. In the example shown, the first adjustor chamber member 62 includes the adjustment projection 64 which extends downwardly and, in the assembled condition, is received in the adjustment recess 68 which is defined by the second adjustor chamber member 66.

The adjustor 54 includes a locking device 70 for locking the assembly 410 in the fixed condition.

In the example shown, the locking device 70 includes a plurality of locking members 72 which extend, in use substantially horizontally, through locking holes 74 defined in the first and second adjustor chamber members 62, 66. The locking holes 74 could be pre-formed or formed in situ, or some combination thereof.

Some of the holes 74 could be elongate, in the form of slots, with a longitudinal axis which is aligned substantially vertically.

In one example, in use, the first adjustor chamber member 62 is located at a required height relative to the second adjustor chamber member 66, with the adjustment projection 64 located in the adjustment recess 68. The locking holes 74 are then formed by drilling through the second adjustor chamber member 66 and the adjustment projection 64 and the locking members 72 located through the locking holes 74.

The adjustor 54 includes adjustor fixing material 100 which is located in the adjustment recess 68 between the adjustment projection 64 of the first adjustor chamber member 62 and the second adjustor chamber member 66. The adjustor fixing material 100 is a settable material which is movable between a relatively fluid condition, in which the adjustor fixing material 100 can flow, and a relatively solid condition, in which the fixing material 100 substantially does not flow but is substantially solid. The adjustor fixing material 100 could be a cementitious material, a polymer modified cementitious material, an epoxy grout or the like. In the assembled condition, the adjustor fixing material 100 substantially fills adjustment spaces 106 defined in the adjustment recess 68 between the adjustment projection 64 of the first adjustor chamber member 62 and the second adjustor chamber member 66.

Fig. 9 shows a fifth embodiment, a ground surface access assembly 510. This embodiment is similar to the embodiment shown in Fig. 7, except that, rather than the adjustment member 56, the adjustor 54 comprises one or more packing members 108, which, in use, are located vertically between the frame interlock projection 34 and the chamber recess base wall 60.

Fig. 10 shows a sixth embodiment, a ground surface access assembly 610. This embodiment is similar to the embodiment shown in Fig. 8, except that, rather than the locking members 72, the adjustor 54 comprises one or more packing members 108, which, in use, are located vertically between the adjustment projection 64 of the first adjustor chamber member 62 and the second adjustor chamber member 66.

Fig. 1 1 shows a frame 1 12 only of a seventh embodiment, a ground surface access assembly 710. In this embodiment, the frame interlock projection 34 defines a plurality of interlock apertures 1 14, which in this example are through apertures.

In use, the fixing material 50 locates in the apertures 1 14. Advantageously, this increases interlock between the frame 1 12 and the fixing material 50 and in particular, vertical interlock between the frame 1 12 and the fixing material. Also, the apertures 1 14 reduce the weight of the frame 1 14 which reduces the frame cost and reduces manual handling risk.

The apertures 1 14 could be of any suitable number, spacing, size and shape, and could be in the form of recesses rather than through holes, or a combination thereof. Fig. 12 shows a frame 112 only of an eighth embodiment, a ground surface access assembly 810. In this embodiment, the frame interlock projection 34 reduces in cross-sectional width. In the example shown, the frame interlock projection 34 is stepped in cross-section. The frame interlock projection 34 comprises an upper part 34A, a middle part 34B and a lower part 34C, with a step 116 between each part. The middle part 34B is narrower in cross-section width than the upper part 34A and the lower part 34C is narrower in cross-section width than the middle part 34B, so that the projection 34 progressively reduces in cross-sectional width.

The reduced width parts 34B, 34C reduce the weight of the frame 114, which reduces the frame cost and reduces manual handling risk.

The frame interlock projection 34 could reduce in cross sectional width in other ways. For example, the frame interlock projection 34 could be tapered, or both tapered and stepped.

The steps 116 and the reduced width parts 34A, 34B, 34C could be of any suitable number, spacing, size and shape.

Other Modifications

Various other modifications could be made without departing from the scope of the invention. The ground surface access assembly and the various components thereof could be of any suitable size and shape, and could be formed of any suitable material (within the scope of the specific definitions herein).

For example, the upper chamber part could be formed of a metallic material, such as mild steel, or of a cast material, or of a combination of materials, such as mild steel, concrete, glass fibre and/or resin, polycarbonate, resin composite and/or glass reinforced materials. In some embodiments the upper chamber part could comprise a metal upper part and a lower part formed of plastics materials such as polycarbonate, resin composite and/or glass reinforced materials.

The frame could be circular, triangular, square or rectangular in plan shape. The ground surface access assembly could comprise one, two or more covers. The ground surface access assembly could comprise a manhole frame and cover(s), or a gully and grating(s).

The interlock feature of the frame could define a recess and the interlock feature of the upper chamber part could comprise a projection. The interlock features of both the frame and the upper chamber part could include both recesses and projections.

The adjustment feature of the first adjustor chamber member could define a recess and the adjustment feature of the second adjustor chamber member could comprise a projection.

Any of the features or steps of any of the embodiments shown or described could be combined in any suitable way, within the scope of the overall disclosure of this document.

There is thus provided a ground surface access assembly with a number of advantages over conventional arrangements. The ground surface access assembly provides direct contact between the frame and the chamber structure eliminating the risk of degradation of an intermediate bedding layer. The frame is only vertically supported by the upper chamber part, reducing the degradation of the surround material caused by movement of the frame. The mutually cooperating interlock features of the frame and the upper chamber part interlock to resist lateral relative movement of the frame and the upper chamber part, reducing the risk of installation failure.