AU727064B2 - Device for mounting an access cover - Google Patents

Abstract

The present invention relates to a device for mounting an access cover (60) in a wearing surface, for example a road surface, having a wear course (7) overlying a base course (8), the device comprising a service frame (50) in which the cover is removably received and a main frame (20) for mounting below the base course, wherein the service frame is movable to a plurality of positions relative to the main frame including a first position at which, in use, a top surface (62) of the access cover is substantially flush with the top surface (11) of the wearing course and a second position at which, in use, the top surface of the access cover is substantially flush with the bottom surface of the base course. A method of resurfacing a road or the like is also provided.

Description

WO 97/37086 PCT/GB97/00887 1 DEVICE FOR MOUNTING AN ACCESS COVER The present invention relates to a device for mounting an access cover, such as a manhole cover, in a wearing surface.

For the avoidance of doubt by the term wearing surface is meant any surface, such as roads and pavements, which require periodic resurfacing.

Access covers are a common feature of road and pavement surfaces and provide access to underground services and installations, such as sewage, telephone, electrical, gas and water installations. The access cover generally resides in a supporting frame which is formed from cast iron and extends down into the foundations beneath the road or pavement and may be set therein with concrete or a similar material.

The level at which the frame is set into the foundation is chosen such that, with the access cover residing in the frame, the upper surface of the access cover lies substantially flush with the road surface.

Due to wear from traffic, road and pavement surfaces require periodic resurfacing.

Resurfacing of the wearing surface may be effected either by planing down the original surface followed by laying a new surface at substantially the same level as the original surface or by simple laying a new surface on the existing surface.

SUBSTITUTE SHEET (RULE 261 WO 97/37086 PCTGB97/00887 2 In the former case the cutting gear of the planing apparatus may collide with the upper part of the support frame, damaging both the cutting gear and the support frame. It will be appreciated that it is also difficult to work around the protruding parts.

Furthermore, once the road or pavement surface has been planed, parts of the supporting frame which stand proud of the surface pose a major safety hazard to traffic. In the latter case, in order to raise the access cover to the level of the new road or pavement surface, the support frame needs to be dug up and reset at the new higher level. This is clearly time consuming and expensive.

Accordingly, the present invention provides a device for mounting an access cover in a wearing surface, for example a road surface, having a wear course overlying a base course, the device comprising a service frame in which the cover is removably received and a main frame for mounting below the base course, wherein the service frame is movable to a plurality of positions relative to the main frame including a first position at which, in use, a top surface of the access cover is substantially flush with the top surface of the wearing course and a second position at which, in use, the top surface of the access cover is substantially flush with the bottom surface of the base course.

SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 -3- Preferably the service frame is supported on the main frame by support means. The support means are preferably adjustable and/or removable. In this case, adjustment and/or removal of the support means enables the service frame to be moved relative to the 'main frame to a plurality of positions including the first and second positions.

In a preferred embodiment of the present invention there is provided a device for mounting an access cover in a wearing surface, for example a road surface, having a wear course overlying a base course, the device comprising a service frame in which the cover is removably received, a main frame for mounting below the base course, and support means to support the service frame on the main frame at a first position at which, in use, a top surface of the access cover is substantially flush with the top surface of the wearing course, wherein removal and/or adjustment of the support means enables the service frame to be moved relative to the main frame to a second position at which, in use, the top surface of the access cover is substantially flush with the bottom surface of the base course.

The service frame is preferably an open annular or rectangular frame having at a base thereof an outwardly extending flange. The service frame typically has a height of from about 8cm to 18cm, more SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 4 typically from about 10cm to about 16cm. The access cover is preferably removably received in the service frame, but may also be hingedly connected thereto.

The main frame is preferably an open annular or rectangular frame having at a base thereof an inwardly extending flange. Advantageously the main frame surrounds the service frame at the second position.

More than one main frame may be provided depending on the depth of the access hole. In this case the two or more main frames are preferably designed to be stackable on top of one another. It will be appreciated that the distance the main frame extends vertically may be adjusted by providing grout, cement or other packing material between a bottom surface thereof and the ground therebelow.

Preferably the support means comprises one or more collars, preferably disposed between an upper surface of the flange of the main frame and a lower surface of the flange of the service frame. The height of the one or more collars relative to the main frame may be adjusted by providing grout, cement or other packing material between a bottom surface thereof and the upper surface of the flange of the main frame. The one or more collars may comprise separable segments.

The height of the service frame relative to the support means may be adjusted by providing grout, SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 5 cement or other packing material between a bottom surface thereof and an upper surface of the support means.

The support means preferably further comprises a height-adjustable spacer element. In this case, the height-adjustable spacer element preferably comprises a collar and wedge arrangement, a collar having one or more adjustable screws running therethrough, or one or more hydraulic jacks or rams or a combination thereof.

The device according to the present invention may further comprise one or more extension collars located on a top portion of the main frame and/or one or more spacer elements located on a top portion of the service frame.

The vertical distance between the top surface of the access cover at the first position and the top surface thereof at the second position is preferably from about 6cm to about 14cm, more preferably from about 8cm to about 12cm, still more preferably about 10cm. Accordingly, in moving from the first position to the second position, the service frame is displaced by a vertical distance of preferably from about 6cm to about 14cm.

The present invention also provides for a method of resurfacing a wearing surface having a wear course overlying a base course, wherein a device as herein described is sited in the wearing surface, the method SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 6comprising the steps of: moving the service frame to the second position; planing down the wear and base courses to the desired depth; moving the service frame relative to the main frame to a position such that the top surface of the access cover will be substantially flush with the top surface of the base course to be laid; laying the base course; moving the service frame such that it will be at substantially the first position when the wear course is laid; and laying the wear course.

In an alternative embodiment, the present invention provides a method of laying a new wear surface on a wearing surface having a wear course overlying a base course, wherein a device as herein described is sited in the wearing surface, the method comprising the steps of: moving the service frame to a level at which the top surface of the access cover will be substantially flush with the top surface of the new wear course to be laid; and laying the wear course.

The present invention also provides for a method of resurfacing a wearing surface having a wear course overlying a base course, wherein a device as herein SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 7 described and comprising support means is sited in the wearing surface, the method comprising the steps of: adjusting and/or removing the support means such that the service frame is in the second position; planing down the wear and base courses to the desired depth; adjusting and/or reinserting the support means such that the top surface of the access cover will be substantially flush with the top surface of the base course to be laid; laying the base course; adjusting the support means such that the service frame will be at substantially the first position when the wear course is laid; and laying the wear course.

In an alternative embodiment, the present invention also provides for a method of laying a new wear surface on a wearing surface having a wear course overlying a base course, wherein a device as herein described and comprising support means is sited in the wearing surface, the method comprising the steps of: adjusting the support means to raise the service frame to a level at which the top surface of the access cover will be substantially flush with the top surface of the new wear course to be laid; and laying the wear course.

It will be appreciated that the device as herein SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 8 described can be substituted for existing conventional devices when the time comes to resurface a road or pavement, for example. All that is required is for a template to be placed over the existing manhole frame and for the road or pavement layers to be cut to the desired depth. Thereafter, the manhole brickwork and arisings can be removed and the new device positioned in place in the manner as described above.

The present invention will now be further described with reference to the following drawings in which: Figure 1 is a schematic vertical cross-sectional half view of a device according to the present invention; Figure 2 is a plan view of a collar of the height-adjustable spacer element of the support means; Figure 3 is a vertical cross-section through line AA' of the plan view illustrated in Figure 2 showing tapered recesses in the collar of the heightadjustable spacer element; Figure 4 is a plan view of an alternative base collar of the support means; Figure 5 is a vertical cross-sectional illustration of a main frame for use with the base collar of Figure 4; Figure 6 is a plan view of an alternative main frame according to the present invention which is SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 9 adapted to be stackable; Figure 7 is a vertical cross-section through line BB' of the plan view illustrated in Figure 6; and Figure 8 is a plan view of an alternative support means collar for use with the main frame illustrated in Figures 6 and 7.

In Figure 1, a device 1 according to the present invention is shown sited in a road 5. The vertical cross-sectional view shows one half of the device 1 and the other half is simply a mirror image of this half about the dashed centre line of the access hole The device 1 comprises a main frame 20 formed from concrete and having an open rectangular form with an upwardly extending wall portion 21 and an inwardly extending flange portion 22 at its base. The main frame 20 has a squarish/rectangular horizontal crosssection (not shown) and the wall portion 21 thereof surrounds the access hole 15. A ridge 23 extends around the upper surface 24 of the wall portion 21 of the main frame 20 such that the outer top edge 25 is at a higher level than the inner top edge 26.

The main frame 20 sits on a service chamber 6 and the remainder of the road 5 consists of a wear course 7 (approximately 4cm depth) overlying a base course 8 (approximately 6cm depth), beneath which is a sub-base course 9. It will be appreciated that the wear 7, SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 10 base 8 and sub-base 9 courses may themselves each comprise a plurality of layers.

A first extension collar 30 is located on the upper surface 24 of the wall portion 21 of the main frame 20. The first extension collar 30 extends upwards from the sub-base course 9 to the top 10 of the base course 8 and has a similar horizontal crosssection (not shown) to that of the main frame 20. The first extension collar 30 is removably located on the main frame 20 by virtue of a ridge 31 provided around its base 32, which cooperates with the ridge 23 on the upper surface 24 of wall portion 21. A ridge 33 around the upper surface 34 of the first extension collar 30 is also provided.

Removably located on the upper surface 34 of the first extension collar 30 is an optional second extension collar 40, again of similar horizontal cross-section (not shown) to that of the main frame The second extension collar 40 has a similar form to that of the first extension collar 30 and extends upwards from the base course 8 to a position adjacent to the top 11 of the wear course 7. The second extension collar 40 has a ridge 41 around its base 42 which cooperates with the ridge 33 on the upper surface 34 of the first extension collar 30. A ridge 43 around the upper surface 44 of the second extension collar 40 is also provided. Both the first 30 and SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 11 second 40 extension collars are formed from concrete.

The main frame 20 and the two extension collars and 40 surround a service frame 50, which is formed from cast iron and is an open rectangular frame having an upwardly extending wall portion 51 and outwardly and inwardly extending flange portions, 52 and 52a, respectively, at its base. Accordingly, the service frame 50 has an inverted T-section. The service frame has a squarish horizontal cross-section (not shown) and the wall portion 51 thereof defines the access hole 15. The service frame 50 has a plurality of strengthening members 53 which join the outside surface 54 of the wall portion 51 to the upper surface of the flange portion 52.

Removably received in the service frame 50 is an access cover 60 which comprises a horizontally extending cover portion 61 and a downwardly extending wall portion 63. The horizontal cross-section (not shown) of the cover portion 61 can take a variety of forms, such as circular or square, but is preferably tailored to suit the service frame 50. The base of the downwardly extending wall portion 63 rests on the upper surface 57 of flange portion 52a, and hence the access cover 60 is supported on the service frame The purpose of the access cover 60 is to prevent objects falling into the access hole 15. The cover portion 61 of the access cover 60 has a top surface 62 SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 12 which is substantially flush with the top surface 11 of the wear course 7.

Support means 70 are positioned between the top surface 27 of the flange portion 22 of the main frame 20 and the bottom surface 58 of the flange portion 52 of the service frame 50. The support means 70 is removable and comprises a base collar 71 and a heightadjustable spacer element 80. The base collar 71 has a squarish horizontal cross-section (not shown) and a top surface 72. The aperture in the base collar 71 coincides substantially with the access hole 15. The base collar 71 is removably located in this position by means of sand grout 100. Positioned on top of the base collar 71 is the height-adjustable spacer element 80. This also comprises a collar 81 having a squarish horizontal cross-section (not shown) and an aperture coinciding substantially with that of the base collar 71. Around the upper surface 82 of collar 81, there are one or more tapered recesses, such as that shown at 85. One or more wedges are inserted into these recesses, such as the wedge shown at 86, whereby the taper of the wedge 86 cooperates with the taper of the recess 85. The tapered recess 85 and wedge 86 are shaped such that the top surface 87 of the wedge 86 remains substantially horizontal. Lateral movement of wedge 86 in the tapered recess 85 (and the lateral movement of the other wedges in the other tapered SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 13 recesses which are not shown) enables the height of the service frame 50 to be carefully adjusted.

Furthermore, tilt can be catered for by laterally moving the wedges independently of one another. The bottom surface 58 of the flange portion 52 of the service frame 50 rests on the top surface 87 of the wedge 86 (and also on the top surfaces of the other wedges not shown). It will be appreciated that the service frame 50 may also be moved laterally within the main frame When the service frame 50 is at the desired height, that is when the top surface 62 of the cover portion 61 of the access cover 60 is substantially flush with the top surface 11 of the wear course 7, the service frame 50 is semi-permanently fixed in place by inserting grout, cement or other packing material in the gap between the bottom surface 58 of flange portion 52 and the top surface 82 of collar 81.

Once set, wedge 86 (and the other wedges not shown) can either be removed or left in place.

In Figure 2 a plan view of the collar 81 of the height-adjustable spacer element 80 is shown. The collar 81 has four walls 83a-d which define a central squarish aperture 84. In a region in the middle of the upper surface 82 of each of the four walls 83a-d, there are tapered recesses 85a-d, respectively. The recesses 85a-d extend from the outer edges 86a-d to SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 14 the inner edges 87a-d of the four wall 83a-d, respectively.

Figure 3 is a vertical cross-section through line AA' showing the tapered recesses 85a and c in opposing walls 83a and c, respectively, and also the tapered recess 85d in wall 83d. The height of the tapered recesses at 83a and c decreases from the outer edges 86a and c to the inner edges 87a and c, respectively.

Figure 4 shows a plan view of a base collar for use in an alternative embodiment of the removable support means 70. The base collar 90 in this embodiment of the present invention is similar to the collar illustrated in Figure 2, but with the tapered recesses removed, hence resulting in four equal and separate collar quarters 91a-d. When the collar quarters 91a-d are positioned as shown, they define a central squarish aperture 92 with regular gaps 93a-d between the collar quarters.

In Figure 5 a vertical cross-section of a main frame 20 for use with the base collar 90 of Figure 4 is shown. Four equally spaced raised sections, only three shown at 29a-c, are provided on the top surface 27 of the flange portion 22. The dimensions and positions of the raised sections 29a-c are such that they cooperate with the gaps 93a-d between the collar quarters of the base collar 90 shown in Figure 4.

Accordingly, the four collar quarters 91a-d are SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/0088 7 15 removably located on the top surface 27 of the flange portion 22 of the main frame 20. Jacks, such as of the hydraulic type or of the spring return ram variety, can now be positioned on the top surface of each of the three raised sections 29a-c (and also on the fourth raised section not shown) and flange portion 52 of the service frame 50 rested thereon.

The service frame 50 can then be raised or lowered to the desired level. With the jacks in place, grout, cement or other suitable packing material is inserted in the space between the bottom surface 58 of flange portion 52 and the top surfaces of the four collar quarters 91a-d. Once the grout or cement has set, the jacks may be removed. If the level needs to be changed again, all that is required is for the jacks to be reinserted into their former positions and for the service frame 50 to be jacked up during which process the grout or the cement is fractured and can be removed. Once at the desired new level, fresh cement or grout is inserted. As an alternative to using jacks to raise the service frame, pulling or lifting apparatus located above the service frame and releasably attached thereto may be used.

When the time comes to resurface the wearing surface, the following step are taken with reference to Figures 1 and 2. First, the support means 70 are removed, to allow the service frame 50 to be lowered SUBSTITUTE SHEET (AULE 26) WO 97/37086 PCT/GB9700887 16 down the access hole 15 and positioned on the top surface 27 of the flange portion 22 of the main frame The service frame 50 and access cover 60 are consequently conveniently located under the road surface without disturbing the road. Next, the road is planed down up to and including the base course 8.

In this process, the first 30 and second 40 extension collars are either removed or broken-up. The presence of the access cover 60 prevents objects and debris from falling down into the access hole Once the surface has been planed down to the depth required, the service frame 50 and access cover 60 are removed from the main frame 20 and the base collar 71 of the removable support means 70 is relocated on the top surface 27 of the flange 22 of the main frame The service frame 50 and access cover 60 are then placed back into the main frame 20, the bottom surface 58 of the flange portion 52 resting on the top surface 72 of the base collar 71. The top surface 62 of the access cover 60 is now at substantially the height of the new base course to be laid. A replacement first extension collar 30 up to this height is now added to the main frame Once the new base course has been laid, the service frame 50 and access cover 60 are once more removed or raised from the main frame 20 and the height-adjustable spacer element 80 is relocated on SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 17 the top surface 72 of the base collar 71. The service frame 50 and access cover 60 are then placed back into the main frame 20, the bottom surface 58 of the flange portion 52 resting on the top surface 82 of collar 81 or on the top surface 87 of wedge 86 (and the top surfaces of the other wedges not shown) depending upon whether or not the wedges have been inserted in the recesses. A second extension collar 40 is added to the first extension collar 30 to bring the main frame to substantially the new level of the wear course to be laid. The wear course is then laid and the height of the service frame 50 can be adjusted if necessary via the wedges, such as that shown at 86, so that the top surface 62 of the access cover 60 lies substantially flush with the newly laid wear surface.

It will be appreciated that tilt of the road can be catered for by adjusting the wedges by differing amounts.

When the level is correct, grout or cement or other packing material is inserted in the gap between the bottom surface 58 of the flange portion 52 of the service frame 50 and the upper surface 82 of the collar 81 of the height-adjustable spacer element When this material has set, the wedges are either removed or left in place.

When the time comes again for the road to be resurfaced, the wedges are reinserted into their SUBSTITUTESHEET (RULE 26) WO 97/37086 PCTIGB97100887 18 former positions and the service frame 50 is raised.

By this process the grout or cement in the gap between the service frame 50 and collar 81 and also the base and wear course material in the space between the vertical wall 51 of the service frame 50 and the extension collars 30 and 40 are fractured. The use of the extension collars 30 and 40 obviates the need to fracture material not lying in this space, which would require significant additional force.

Alternatively, if the road is to simply have another wear layer laid over the existing wear course 7, all that is required is for the service frame 50 to be raise up to and set at the new level and this is achieved in the manner as detailed above.

With regard to the support means as shown in Figures 4 and 5, the wearing surface is resurfaced in a similar manner to that described above. The adjustment of the height of the service frame however, is effected through the use of hydraulic jacks, rams, pulling or lifting apparatus as hereinbefore described and the height-adjustable spacer element 80 may accordingly be dispensed with.

Referring now to Figures 6 and 7 which show an alternative embodiment of a main frame 100 which may be stacked on top of another such frame. Accordingly, depending upon the depth of the access hole, one or more of the frames 100 may be used. Like the main SUBSTITUTE SHEET RA1E -26) WO 97/37086 PCTGB97/00887 19 frame illustrated in Figures 1 and 5, main frame 100 has an upwardly extending wall portion 101 and inwardly extending flange portion 102 at its base.

The main frame 100 has a squarish horizontal crosssection and the wall i01 and flange 102 portions define a central squarish aperture 103. Compared to the main frame shown in Figures 1 and 5, frame 100 is adapted to be stackable by virtue of a recess 104 formed around its outer lower edge, which, it will be appreciated, can cooperate with the upper part of a wall portion of another such frame.

Four equally spaced recesses 105a-d are provided in flange portion 102 at positions approximately midway along the four sides and these facilitate lifting of the support means and service frame (not shown) by the use of one or more levers for example.

Figure 8 shows an alternative support means collar 110 for use with the stackable main frame 100 of Figures 6 and 7. The collar 110 in this embodiment of the invention comprises four equal and separate collar quarters llla-d. When the collar quarters llla-d are positioned as shown, they define a central squarish aperture 112 which corresponds substantially with aperture 103 (see Figure In contrast to the collar quarters of the base collar illustrated in Figure 4, collar quarters llla-d are not diagonally symmetrical. Cut-out portions 113a-d are provided in SUBSTITUTE SHEET (RULE 26) WO 97/37086 PCT/GB97/00887 20 collar quarters llla-d respectively to facilitate lifting of the service frame (not shown) by the use of one or more levers for example. Cut-out portions 113a-d are positioned away from the centre of the four sides of the collar and, accordingly, are out of alignment with respect to recesses 105a-d (see Figures 6 and In contrast to the support means illustrated in Figure 1, no height-adjustable spacer element is provided. Consequently, in this embodiment of the invention, the service frame is moved from the first position to the second position simply by removal of collar 110. Fine adjustment of the height of the service frame may be achieved by the use of grout or cement or other packing material between the various mating surfaces. Screw holes 114a-d and screws (not shown) may also be provided to enable further height and/or tilt adjustment.

The device and method of the present invention address many of the problems associated with the prior art, for example the hazard of parts of the supporting frame standing proud of the surface. The device of the present invention may be used in a variety of differently sized access holes. Inspection of the access hole is relatively simple and the device is easy to dismantle. Fine adjustment and tilt of the access cover is provided.

SUBSTITUTE SHEET (RULE 26) P:\OPER\GMP2 29 86- 9 7 p2oAd.27/09/OO Throughout this specification and the claims which follow, unless the context requires otherwise, the word comprise", and variations such as comprises" and "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

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Claims (6)

1. A device for mounting an access cover in a wearing surface, for example a road surface, having a wear course overlying a base course, the device comprising a service frame in which the cover is removably received, a main frame for mounting below the base course, the main frame being made up of one or more stackable frames each frame having an upwardly extending wall portion and an inwardly extending flange portion at a base thereof and a recess formed around an outer lower edge, which recess is co- operable with the upper part of a wall portion of another stackable frame, and support means to support the service frame on the main frame at a first position at which, in use, a top surface of the access cover is substantially flush with the top surface of the wearing course, wherein removal and/or adjustment of the support means enables the service frame to be moved relative to the main frame to a second position at which, in use, the top surface of the access cover is substantially flush with the bottom surface of the base course.

2. A device as claimed in claim 1, wherein the main frame has a squarish horizontal cross-section and 4 wherein four equally spaced recesses are provided in AMENDED SHEET ro IPEA/EP 22 the flange portion thereof at positions approximately midway along the four sides.

3. A device as claimed in claim 2, wherein the support means comprises four equal and separate diagonally asymmetrical collar quarters, each collar quarter having a cut-out portion, wherein the cut-out portions are out of alignment with respect to the recesses in the flange portion of the main frame.

4. A device as claimed in any one of the preceding claims, wherein the service frame is an open rectangular frame having at a base thereof an outwardly extending flange. A device as claimed in any one of the preceding claims, further comprising one or more extension collars located on a top portion of the main frame.

6. A device for mounting an access cover in a wearing surface, for example a road surface, having a wear course overlying a base course, the device comprising a service frame in which the cover is removably received, a main frame for mounting below the base course, and support means to support the service frame on the main frame at a first position at which, in use, a top surface of the access cover is AMENDED SHEET IPEA/EP P:APER\GCP2U 2 9

86-97 sp.doc-27/09/00 -23- substantially flush with the top surface of the wearing course, wherein removal and/or adjustment of the support means enables the service frame to be moved relative to the main frame to a second position at which, in use, the top surface of the access cover is substantially flush with the bottom surface of the base course, wherein one or more extension collars is/are located on a top portion of the main frame, and wherein the service frame is an open annular or rectangular frame having at a base thereof an outwardly extending flange. 7. A device as claimed in claim 6, wherein the main frame is an pen annular or rectangular frame having at a O. base thereof an inwardly extending flange. S- 8. A device as claimed in any one of the preceding claims, wherein the main frame surrounds the service frame at the second position. 20 9. A device as claimed in any one of the preceding claims, wherein the support means comprises one or more collars or one or more height-adjustable spacer elements or a combination thereof. 10. A device as claimed in claim 4 or claim 5 or any one of claims 7 to 9, wherein the support means comprises one or more collars disposed between an upper surface of the flange of the main frame and a lower surface of the flange of the service frame. 11. A device as claimed in claim 9 or claim n wherein the one or more collars comprise separable segments. P:AOPERGCP\2 9 86- 9 7 spc.doc-27/09/00 -24- 12. A device as claimed in any one of claims 9 to 11, wherein the support means further comprises a height- adjustable spacer element. 13. A device as claimed in claim 12, wherein the height-adjustable spacer element comprises a collar and wedge arrangement, a collar having one or more adjustable screws running therethrough, or one or more hydraulic jacks or rams or a combination thereof. 14. A device as claimed in any one of the preceding claims, wherein grout, cement or packing material is provided between a bottom surface of the main frame and the 15 ground therebelow. 15. A device as claimed in any one of the preceding claims, wherein grout, cement or packing material is provided between the support means the main frame. 16. A device as claimed in any one of the preceding claims, wherein grout, cement or packing material is provided between the service frame and the support means. 17. A device as claimed in any one of the preceding claims, further comprising one or more spacer elements located on a top portion of the service frame. 18. A device as claimed in any one of the preceding claims, wherein the vertical distance between the top surface and the access cover at the first position and the 9 top surface thereof at the second position is from 6 cm to P:\OPER\GCB22986-97 spedoc-27/0900 14 cm, preferably from 8 cm to 12 cm, more preferably approximately 10 cm. 19. A device as claimed in any one of claims 6 to 18, wherein the main frame is made up of one or more stackable frames each having an upwardly extending wall portion and an inwardly extending flange portion at a base thereof and a recess formed around an outer lower edge, which recess is co-operable with the upper part of a wall portion of another stackable frame. A method resurfacing a wearing surface having a wear course overlying a base course, wherein a device as claimed in any one of the preceding claims is sited in the 15 wearing surface, the method comprising the steps of: removing and/or adjusting the support means such that the service frame is in the second position; planing down the wear and base courses to the desired depth; 20 reinserting and/or adjusting the support means such that the top surface of the access cover will be substantially flush with the top surface of the base course to be laid; laying the base course; adjusting the support means such that the service frame will be at substantially the first position when the wear course is laid; and laying the wear course. 21. A method of laying a new wear surface on a wearing S surface having a wear course overlying a base course, wherein a device is claimed in any one of claims 1 to 19 is P:kOPERGCPX2 2 9 6-97 spe.doc-27/09/0 -26- sited in the wearing surface, the method comprising the steps of: adjusting the support means to raise the service frame to a level at which the top surface of the access cover will be substantially flush with the top surface of the new wear course to be laid; and laying the wear course. 22. A device for mounting an access cover in a wearing surface substantially as hereinbefore described with reference to the accompanying drawings. 23. A method of laying a new wear surface on a wearing surface substantially as hereinbefore described with 15 reference to the accompanying drawings. 0 DATED this 2 9 t h day of September, 2000 CSR LIMITED 20 by its Patent Attorneys 4 DAVIES COLLISON CAVE 0 000*