EP1752584A2 - Access cover - Google Patents
Access cover Download PDFInfo
- Publication number
- EP1752584A2 EP1752584A2 EP06254026A EP06254026A EP1752584A2 EP 1752584 A2 EP1752584 A2 EP 1752584A2 EP 06254026 A EP06254026 A EP 06254026A EP 06254026 A EP06254026 A EP 06254026A EP 1752584 A2 EP1752584 A2 EP 1752584A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- reinforcement part
- cover according
- main
- auxiliary
- cover
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 230000002787 reinforcement Effects 0.000 claims abstract description 95
- 238000012360 testing method Methods 0.000 claims description 54
- 230000001419 dependent effect Effects 0.000 claims 3
- 238000013461 design Methods 0.000 description 11
- 239000000463 material Substances 0.000 description 8
- 230000001105 regulatory effect Effects 0.000 description 7
- 238000004458 analytical method Methods 0.000 description 3
- 238000005266 casting Methods 0.000 description 3
- 230000032258 transport Effects 0.000 description 3
- 229910001141 Ductile iron Inorganic materials 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000000712 assembly Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 238000011960 computer-aided design Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D29/00—Independent underground or underwater structures; Retaining walls
- E02D29/12—Manhole shafts; Other inspection or access chambers; Accessories therefor
- E02D29/14—Covers for manholes or the like; Frames for covers
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D29/00—Independent underground or underwater structures; Retaining walls
- E02D29/12—Manhole shafts; Other inspection or access chambers; Accessories therefor
- E02D29/14—Covers for manholes or the like; Frames for covers
- E02D29/1454—Non-circular covers, e.g. hexagonal, elliptic
Definitions
- the deformation reducing means are arranged so that under load a deformation of one part of the cover acts against a deformation of another part of the cover, to reduce the overall deformation of the cover and hence reduce the permanent set recorded.
- the first and second mountings are the mountings at each end of the longer side.
- Fig. 3 shows one of the covers 12 on its own for clarity.
- Each cover 12 includes a planar part 20 which in use forms an upper surface of the cover 12.
- the shape of the planar part 20 is a right angled triangle, having a longer edge 50 and two shorter edges 52 of substantially equal length.
- the angle between the longer edge 50 and each of the shorter edges 52 is approximately 45°
- the angle between the two shorter edges 52 is approximately 90°.
- Extending downwardly in use from each of the 45° corners 64 are first and second mountings 54, 55 respectively, and extending downwardly in use from the 90° corner 66 is third mounting 56.
- Each of the mountings 54, 55, 56 is in the form of a protrusion, the mountings 54, 55, 56 together forming a non rock three point mounting for the cover 12.
- the maximum length of the auxiliary beam 24 could be between 30 and 50% of the maximum length of the main beam 22, and in one example was approximately 40% of the maximum length of the main beam 22.
Landscapes
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Protection Of Pipes Against Damage, Friction, And Corrosion (AREA)
- Details Of Indoor Wiring (AREA)
- Catching Or Destruction (AREA)
- Devices Affording Protection Of Roads Or Walls For Sound Insulation (AREA)
Abstract
Description
- The present invention relates to access covers, and in particular to ground surface access covers such as manhole covers.
- Access covers undergo a variety of tests which are related to the type of application in which the access cover will be used, in accordance with regulatory standards. Currently, access covers are specified in accordance with European Standard EN124. This standard specifies that the cover is subjected to a permanent set test to test permanent deformation of the cover under load, followed by an ultimate load test. In the permanent set test, the cover is subjected to five load cycles up to two-thirds of the ultimate load, after which the permanent deformation is recorded. In the ultimate load test, a specified ultimate test load is applied for a specified period of time.
- Conventionally, the design of access covers has been relatively crude, but as the cost of raw materials has increased, designers have increasingly sought to match the design of the cover to the requirements of the regulatory standard. The use of sophisticated design techniques such as finite element analysis (FEA) and computer aided design using three dimensional models has helped designers to minimise material requirements while maximising the strength of the covers, in particular in meeting the ultimate load test specification. However as designs become more complex, the ability of computer aided design and FEA programmes to accurately model the performance of the designs of the covers is reduced, and in particular, such techniques are generally poor in modelling and predicting permanent set.
- Typically covers are provided as component parts of access assemblies, each assembly comprising a cover or pair of covers which is received within and supported by a frame. In testing the assembly is arranged to simulate a roadway installation with the cover or covers supported within the frame.
- For certain applications the or each cover must be prevented from rocking in the frame during trafficking, and a common means of achieving a non rock support is for the cover to be supported on a three point mounting. This has led to the use of triangular covers, and "double triangular" pairs of covers within rectangular or square frames.
- Each cover conventionally includes a main reinforcement beam which spans between two of the mountings and beneath the area over which the load is applied. Simple examples of such beams can be relatively easily modelled and designed to provide sufficient strength for the covers when tested to meet the ultimate load test specification. However, it can be difficult to model the performance of more complex beams such as curved beams and more difficult still to model the permanent deformation of more complex beams. In such situations, the designer often resorts to scaling the design of the beam by a factor to allow for the permanent set requirements. However such designs are not optimal in that material requirements may be higher than necessary. In the case of covers formed of ductile iron, failure more commonly occurs in the permanent set test due to deformation rather than the ultimate load test.
- Testing has shown that the use of a curved main beam is relatively efficient, and allows a weight saving in material. However the curved beam is relatively "springy" and tends to have a relatively high permanent set in comparison with a linear beam. As the amount of material used is reduced, it has been found that the initial effect is upon an increase in permanent set rather than a reduction in the ultimate load.
- According to the present invention, there is provided a ground surface access cover, the cover including a substantially planar part and a reinforcement arrangement, the reinforcement arrangement being located on an underside in use of the planar part and including an elongate main reinforcement part, the reinforcement arrangement further including deformation reducing means which are arranged so that when the cover is tested in accordance with regulatory standards, the permanent set recorded falls within the regulatory requirements.
- Preferably, the deformation reducing means are arranged so that when the cover is tested in accordance with regulatory standards, the permanent set recorded is substantially zero.
- Preferably, the deformation reducing means are arranged so that under load a deformation of one part of the cover acts against a deformation of another part of the cover, to reduce the overall deformation of the cover and hence reduce the permanent set recorded.
- Preferably, the deformation reducing means connect the one part of the cover to the other part of the cover, to permit the deformation of the one part to act against the deformation of the other part.
- The one part of the cover may be the main reinforcement part. The other part of the cover may be the planar part.
- Preferably, the deformation reducing means include an elongate auxiliary reinforcement part. Preferably, the main and auxiliary reinforcement parts are located substantially alongside each other.
- Further according to the present invention, there is provided a ground surface access cover, the cover including a substantially planar part and a reinforcement arrangement, the reinforcement arrangement being located on an underside in use of the planar part and including an elongate main reinforcement part, the reinforcement arrangement further including deformation reducing means, the deformation reducing means including an elongate auxiliary reinforcement part, the main and auxiliary reinforcement parts being located substantially alongside each other.
- Preferably, the main and auxiliary reinforcement parts are aligned substantially in the same direction.
- Preferably, a test load area is defined on an upper side in use of the planar part, over which area in use a test load is applied. The main reinforcement part and auxiliary reinforcement part may both extend directly underneath the test load area.
- Preferably, the cover includes a plurality of mountings, and may include three mountings. Preferably, the main reinforcement part extends substantially between first and second mountings. Preferably, the auxiliary reinforcement part is aligned between the first and the second mountings.
- Each of the mountings may be located at a corner of a right angled triangle. The triangle may have a longer side and may have two shorter sides, which may be of substantially the same length. Preferably, the planar part has a shape in plan which corresponds to that of the triangle.
- Preferably, the first and second mountings are the mountings at each end of the longer side.
- The main reinforcement part may be non linear in a longitudinal direction, and may be curved in the longitudinal direction. Preferably, the main reinforcement part curves convexly towards the third mounting, which may be the mounting between the two shorter sides. Preferably, the auxiliary reinforcement part is located on the side of the main reinforcement part away from the third mounting.
- Preferably, the auxiliary reinforcement part lies along a chord of the curved main reinforcement part. The auxiliary reinforcement part may extend along only part of the chord.
- Preferably, the main and/or auxiliary reinforcement parts are symmetrical about an axis, and may be symmetrical about the same axis. Preferably, the axis of symmetry extends through the third mounting, and may substantially bisect the longer side.
- Preferably, the deformation reducing means include a web, which may extend between the main and the auxiliary reinforcement parts. More preferably, the deformation reducing means include a pair of spaced substantially parallel webs, which may extend between the main and auxiliary reinforcement parts. Preferably, the depth of the web at one end is substantially the same as the depth of the auxiliary reinforcement part. Preferably, the depth of the web at the other end is substantially the same as the depth of the main reinforcement part.
- Preferably, a fillet extends between the main reinforcement part and the planar part. Preferably, the fillet extends transversely from the main reinforcement part. Preferably, the fillet extends from the main reinforcement part towards the mounting between the two shorter sides.
- Preferably, the cover is formed of a ductile material, and may be formed of ductile iron, and may be formed by casting. Preferably, the cover is formed integrally in one piece.
- Preferably, the main reinforcement part tapers in thickness downwardly in use from the planar part. Preferably, the auxiliary reinforcement part tapers in thickness downwardly in use from the planar part.
- Preferably, the auxiliary reinforcement part is shallower in depth than the main reinforcement part. Preferably, the auxiliary reinforcement part is between 40% and 60% of the depth of the main reinforcement part, and may be approximately 50% of the depth of the main reinforcement part.
- Preferably, the auxiliary reinforcement part is substantially similar in length to the test block. Preferably, the auxiliary reinforcement part is shorter in length than the main reinforcement part. Preferably, the auxiliary reinforcement part is between 30% and 50% of the length of the main reinforcement part, and may be approximately 40% of the length of the main reinforcement part.
- Preferably, the regulatory standard to which the cover is tested is European Standard EN124.
- Further according to the present invention, there is provided a surface access assembly, the assembly including a frame defining an opening and at least one cover as defined in the preceding statements, which in use is supported by the frame in the opening.
- Preferably, the assembly includes a pair of substantially similar covers which may be supported side by side. Preferably, the assembly is arranged so that in use, the test load is applied substantially equally to each of the covers.
- An embodiment 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 perspective view of an access assembly according to the present invention;
- Fig. 2 is a perspective view of the access assembly of Fig. 1 with a test block in position;
- Fig. 3 is a perspective view of a cover according to the invention with the test block in position;
- Fig. 4 is a perspective view from below of the cover of Fig. 3;
- Fig. 5 is a view from below of the cover of Figs. 3 and 4 with the test block in position;
- Fig. 6 is a view from one side of the cover with the test block in position;
- Fig. 7 is a sectional view of two covers with the test block in position as indicated by the section line in Fig. 2;
- Fig 8 is a schematic sectional view along an axis of symmetry of part of a cover not according to the invention undergoing testing; and
- Fig 9 is a schematic sectional view along an axis of symmetry of part of the cover of Figs 1-7 undergoing testing.
- Fig. 1 shows a ground
surface access assembly 10 including a pair ofcovers 12 which are seated in aframe 14. The general arrangement of thecovers 12 andframe 14 is relatively conventional, each cover 12 being substantially triangular in plan and being seated within a substantially square opening defined by theframe 14. - Fig. 3 shows one of the
covers 12 on its own for clarity. Eachcover 12 includes aplanar part 20 which in use forms an upper surface of thecover 12. In plan, the shape of theplanar part 20 is a right angled triangle, having alonger edge 50 and twoshorter edges 52 of substantially equal length. Atcorners 64, the angle between thelonger edge 50 and each of the shorter edges 52 is approximately 45°, and at corner 66, the angle between the twoshorter edges 52 is approximately 90°. Extending downwardly in use from each of the 45°corners 64 are first andsecond mountings 54, 55 respectively, and extending downwardly in use from the 90° corner 66 is third mounting 56. Each of themountings mountings cover 12. - Figs. 4 and 5 are views of the
cover 12 from below. Thecover 12 includes areinforcement arrangement 16 which is located on an underside in use of theplanar part 20. Thereinforcement arrangement 16 includes a main reinforcement part in the form of a curvedmain beam 22. As shown in Fig. 6, themain beam 22 is deeper in section at its middle, and as shown in Fig. 7 the section thickness reduces with the depth away from theplanar part 20. - The
reinforcement arrangement 16 includes deformation reducing means including an auxiliary reinforcement part in the form of a linearauxiliary beam 24, which is located close to and parallel with thelonger edge 50. As shown in Fig. 6, theauxiliary beam 24 is relatively short in comparison with the length of themain beam 22, and also relatively shallow in depth in comparison with the depth of themain beam 22. Theauxiliary beam 24 includes a lowermost substantiallyflat face 70, at each end of which a slopingface 72 extends upwardly to theplanar part 20 at an angle of approximately 45°. - The
main beam 22 and theauxiliary beam 24 are located substantially alongside each other, and are aligned in the same direction, and both extend directly beneath atest load area 42 defined on an upper side in use of theplanar part 20, over which area in use a test load is applied through thetest block 40. - The
main beam 22 extends between the first andsecond mountings 54, 55, and theauxiliary beam 24 is aligned between the first andsecond mountings 54, 55, on the side of the main beam away from the third mounting 56. Theauxiliary beam 24 lies along a chord of the curvedmain beam 22. - The
main beam 22 and the auxiliary beam are both symmetrical about an axis ofsymmetry 44 which bisects thelonger edge 50 and extends through the 90° corner 66. - The deformation reducing means include a pair of spaced, substantially
parallel webs 26, each of which extend between theauxiliary beam 24 and themain beam 22 to connect theauxiliary beam 24 to themain beam 22. Each of thewebs 26 includes alowermost face 74 which extends from the lowermostflat face 70 of theauxiliary beam 24 to a lowermostconcave edge 76 of themain beam 22. Thus the depth of each of thewebs 26 at one end is substantially the same as the depth of theauxiliary reinforcement beam 24 and the depth of each of thewebs 26 at the other end is substantially the same as the depth of themain beam 22. - The
cover 12 includes a pair of projectingnibs 32 which project from the underside of theplanar part 20 and are located on thelonger edge 50. Each of the projectingnibs 32 defines anaperture 34 for receiving a fastener such as a bolt (not shown) to loosely connect onecover 12 to asecond cover 12 in use. - A
fillet 28 extends between themain beam 22 and theplanar part 20 via akeyway compartment 30 on the side of themain beam 22 away from theauxiliary beam 24. Thefillet 28 extends from substantially the full depth of themain beam 20 at its deepest point. - The reinforcement arrangement includes a pair of curved
lateral beams 36 extending from the side of themain beam 22 away from theauxiliary beam 24 to the 90° corner mounting 56, the lateral beams 36 being of lesser depth relative to themain beam 22. These lateral beams 36 provide some stiffness but because of the mode of failure of thecover 12 in testing are of relatively little consequence in reducing the permanent set. - In use, the
frame 14 is installed over, for instance, an inspection chamber and thecovers 12 located in theframe 14. In a typical construction in situ, only the top most edge of theframe 14 and the upper surfaces of thecovers 12 will be visible. In a roadway, thecovers 12 will be subjected to a range of dynamic loads as vehicles pass over the covers. The forces transmitted include both horizontal and vertical components as the vehicles brake, turn, and/or accelerate over the covers. - The approach to setting test specifications for access cover assemblies has been to not to try and attempt to simulate such varying load conditions in a test situation, but to apply a simple static load to the access cover assembly, the load including factors of safety to account for the different loading conditions experienced in practice. Thus, for example, a 38 tonne heavy goods vehicle having five axles with a total of 12 wheels will only apply a load of a little over 3 tonnes per wheel. However, the EN124 test specification for a cover suitable for use in a roadway for trafficking by heavy goods vehicles specifies five loading cycles up to 270kN after which the permanent set is measured, followed by loading to an ultimate test load of 400 kN, or approximately 40 tonnes, for a period of 30 seconds.
- EN124 specifies that the permanent set after the five loading cycles should be no more than 0.2% of the opening. Thus, for example, for a 600mm opening, the limit for permanent set is 1.2mm.
- Fig 2 shows the
access assembly 10 with thetest block 40 in position on the upper surface of thecovers 12. Thetest block 40 transmits the test load substantially equally to each of thecovers 12. Fig 7 is a sectional view of twocovers test block 40 in position with the section taken along line VII-VII of Fig 2, which is also the axis ofsymmetry 44 as shown in Fig 5. Along this section line, themain beams test load area 42. - A cover similar to that described above but without the
auxiliary beam 24 and thus not in accordance with the invention was tested in accordance with the EN 124 test specification. After the permanent set load cycling test, the permanent set was measured at 1.8mm, exceeding the allowable limit of 1.2mm. Ultimate load failure occurred at 480kN, in comparison with the allowable limit of 400kN. Thus the cover exceeded the requirements for ultimate load, but failed the permanent set test. The use of simple 45° fillets on each side of the main beam appeared to make little difference to the permanent set recorded, even when those fillets extended to the full depth of the main beam. - The
cover 12 according to the invention and including theauxiliary beam 24 andwebs 26 was then subjected to testing. Some reduction in the permanent set was anticipated, and had been predicted by finite element analysis methods, but the effect of theauxiliary beam 24 andwebs 26 exceeded expectations, in that the permanent set measured was around approximately zero mm. The ultimate load was similar to before. The test was repeated with alternative covers of similar design, with similar results. - The reason for this result is not yet clearly understood, and permanent set is not accurately predictable by finite element analysis methods. It will be noted however that the
auxiliary beam 24 extends directly underneath thetest load area 42 and is of substantially similar length to the diameter of thetest load area 40. The intention was that rather allowing thecover 12 to deform progressively along the length of thelonger edge 50 to a maximum at the mid point of thelonger edge 50, the extra stiffening of theauxiliary beam 24 would reduce the deformation directly underneath thetest block 40. - However there also appears to be an interaction between the
auxiliary beam 24 and themain beam 22 via thewebs 26. Figs 8 and 9 attempt to illustrate what might be happening. Fig 8 shows a cover 11 not in accordance with the invention, without anauxiliary beam 24. Thetest block 40 applies a load over atest load area 42 on the upper surface in use of theplanar part 20. The load as indicated by arrows A is evenly distributed over thearea 42. The load causes theplanar part 20 to deform by (as it were) creasing along the axis ofsymmetry 44, theplanar part 20 in the region of the axis ofsymmetry 44 deforming downwardly relative to theplanar part 20 in the region of the mountings as shown by arrow B. - As this deformation occurs, the
main beam 22 deforms so that the middle region of theconcave edge 76 of themain beam 22 moves towards thelonger edge 50 to flatten the curve of theconcave edge 76 and accommodate the deformation of theplanar part 20, the deformation of this region of themain beam 22 being shown in Fig 8 by dotted lines and indicated by arrow C. - Fig 9 shows the
cover 12 of the invention undergoing a similar load test to that described in Fig 8. The load acts to deform theplanar part 20 andauxiliary beam 24 downwardly as shown by arrow B, and to deform the middle region of theconcave edge 76 towards thelonger edge 50 as shown by arrow C. Thewebs 26 transmit these deformations towards each other to act against each other to reduce the overall deformation of the cover and hence the permanent set recorded. Careful design (or happy accident) can result in the deformations substantially cancelling each other out, and there being no permanent set recorded. In another example, a negative permanent set was recorded. Thus theauxiliary beam 24 and thewebs 26 form deformation reducing means. - The depth of the
auxiliary beam 24 could be between 40 and 60% of the greatest depth of themain beam 22, and in one example could be approximately 50% of the maximum depth of themain beam 22. - The maximum length of the
auxiliary beam 24 could be between 30 and 50% of the maximum length of themain beam 22, and in one example was approximately 40% of the maximum length of themain beam 22. - Various modifications may be made without departing from the scope of the invention. The main beam could be of any suitable design, and could be of any suitable height, degree of curvature and section shape. The auxiliary beam could be of any suitable length, height and section shape. The webs between the main beam and auxiliary beam could be of any suitable design. A different number of webs could be provided. The main beam, auxiliary beam and webs could be configured differently, and could be located in different positions under the planar part. The planar part could be of different shape. For example, the planar part could be circular.
- There is thus provided a cover which meets the requirements of the regulatory test specifications for ultimate load and deformation, with a reduction in the material used in manufacture. In one example, for a casting weighing 90 kilograms, a reduction of 6 kilograms was achieved, a reduction in material usage of just over 6%. For heavy items such as iron castings, transport costs can be significant, and therefore the cover of the invention allows a saving not only in the cost of material, but also provides a reduction in the cost of transportation.
- 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 (24)
- A ground surface access cover (12), characterised in that the cover includes a substantially planar part (20) and a reinforcement arrangement (16), the reinforcement arrangement being located on an underside in use of the planar part and including an elongate main reinforcement part (22), the reinforcement arrangement further including deformation reducing means (24, 26), the deformation reducing means including an elongate auxiliary reinforcement part (24), the main and auxiliary reinforcement parts being located substantially alongside each other, and aligned substantially in the same direction.
- A cover according to claim 1, in which a test load area (42) is defined on an upper side in use of the planar part, over which area in use a test load (40) is applied, the main reinforcement part and auxiliary reinforcement part both extending directly underneath the test load area.
- A cover according to claims 1 or 2, in which the main reinforcement part extends substantially between first and second mountings (54, 55).
- A cover according to any of the preceding claims, in which the auxiliary reinforcement part is aligned between the first and the second mountings.
- A cover according to claims 3 or 4, in which the cover includes three mountings (54, 55, 56), each of the mountings being located at a corner of a right angled triangle, the triangle having a longer side and two shorter sides, the first and second mountings (54, 55) being the mountings at each end of the longer side and the third mounting (56) being the mounting between the two shorter sides.
- A cover according to any of the preceding claims, in which the main reinforcement part is curved in the longitudinal direction.
- A cover according to claim 6 when dependent on claim 5, in which the main reinforcement part curves convexly towards the third mounting.
- A cover according to claim 7, in which the auxiliary reinforcement part is located on the side of the main reinforcement part away from the third mounting.
- A cover according to any of claims 6 to 8, in which the auxiliary reinforcement part lies along a chord of the curved main reinforcement part.
- A cover according to claim 9, in which the auxiliary reinforcement part extends along only part of the chord.
- A cover according to any of the preceding claims, in which the deformation reducing means include a web (26), which extends between the main and the auxiliary reinforcement parts.
- A cover according to claim 11, in which the deformation reducing means include a pair of spaced substantially parallel webs (26), which extend between the main and auxiliary reinforcement parts.
- A cover according to claims 11 or 12, in which the depth of the or each web at one end is substantially the same as the depth of the auxiliary reinforcement part.
- A cover according to claim 13, in which the depth of the or each web at the other end is substantially the same as the depth of the main reinforcement part.
- A cover according to any of the preceding claims, in which the cover is formed integrally in one piece.
- A cover according to any of the preceding claims, in which the auxiliary reinforcement part is shallower in depth than the main reinforcement part.
- A cover according to claim 16, in which the auxiliary reinforcement part is between 40% and 60% of the depth of the main reinforcement part.
- A cover according to claim 17, in which the auxiliary reinforcement part is approximately 50% of the depth of the main reinforcement part.
- A cover according to claim 2 or any claim dependent thereon, in which the auxiliary reinforcement part is substantially similar in length to the test load area.
- A cover according to claim 2 or any claim dependent thereon, in which the auxiliary reinforcement part is shorter in length than the main reinforcement part.
- A cover according to claim 20, in which the auxiliary reinforcement part is between 30% and 50% of the length of the main reinforcement part.
- A cover according to claim 21, in which the auxiliary reinforcement part is approximately 40% of the length of the main reinforcement part.
- A surface access assembly (10), characterised in that the assembly includes a frame (14) defining an opening and at least one cover (12) as defined in any of the preceding claims, which in use is supported by the frame in the opening.
- A cover according to claim 23, in which the assembly (10) includes a pair of substantially similar covers (12) which are supported side by side.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0515846A GB2429228B (en) | 2005-08-02 | 2005-08-02 | Access cover |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1752584A2 true EP1752584A2 (en) | 2007-02-14 |
EP1752584A3 EP1752584A3 (en) | 2008-05-14 |
Family
ID=34983915
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP06254026A Withdrawn EP1752584A3 (en) | 2005-08-02 | 2006-08-01 | Access cover |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP1752584A3 (en) |
GB (1) | GB2429228B (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2468480A (en) * | 2009-03-06 | 2010-09-15 | Wrekin Welding & Fabrication E | Ground surface access assembly with reinforcements |
CN114150706A (en) * | 2021-11-29 | 2022-03-08 | 安徽省飞龙新型材料有限公司 | Deformable dual-purpose manhole cover and using method thereof |
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FR1480364A (en) * | 1966-03-31 | 1967-05-12 | Sambre & Meuse Usines | Stamp for gaze and gaze with this pad |
GB2116611A (en) * | 1982-02-26 | 1983-09-28 | Brickhouse Dudley Mfg | Manhole frame and cover assembly |
EP0507708A1 (en) * | 1991-04-05 | 1992-10-07 | Societe Anonyme Dite : Sodif | Safety device for hinged manhole cover |
EP0533533A1 (en) * | 1991-09-16 | 1993-03-24 | Pont-A-Mousson S.A. | Locked manhole cover |
EP0541350A2 (en) * | 1991-11-06 | 1993-05-12 | W.J. Furse & Co. Ltd. | Inspection pit, lid and inspection pit assembly |
GB2299603A (en) * | 1995-04-06 | 1996-10-09 | C I S | Manhole cover |
GB2360807A (en) * | 2000-04-01 | 2001-10-03 | Atlanta Impex Ltd | Access Cover Component and Assembly |
EP1229173A1 (en) * | 2001-02-06 | 2002-08-07 | Karl Kortmann | Cover device for pipes, particularly man-holes |
JP2002348895A (en) * | 2001-05-23 | 2002-12-04 | Asahi Tec Corp | Underground structure cover |
US20040042849A1 (en) * | 2002-08-15 | 2004-03-04 | Bescal, Inc. | Utilities access closure |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB0330271D0 (en) * | 2003-12-31 | 2004-02-04 | Saint Gobain Pipelines Plc | A covering for an access aperture,and related assemblies |
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2005
- 2005-08-02 GB GB0515846A patent/GB2429228B/en active Active
-
2006
- 2006-08-01 EP EP06254026A patent/EP1752584A3/en not_active Withdrawn
Patent Citations (10)
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FR1480364A (en) * | 1966-03-31 | 1967-05-12 | Sambre & Meuse Usines | Stamp for gaze and gaze with this pad |
GB2116611A (en) * | 1982-02-26 | 1983-09-28 | Brickhouse Dudley Mfg | Manhole frame and cover assembly |
EP0507708A1 (en) * | 1991-04-05 | 1992-10-07 | Societe Anonyme Dite : Sodif | Safety device for hinged manhole cover |
EP0533533A1 (en) * | 1991-09-16 | 1993-03-24 | Pont-A-Mousson S.A. | Locked manhole cover |
EP0541350A2 (en) * | 1991-11-06 | 1993-05-12 | W.J. Furse & Co. Ltd. | Inspection pit, lid and inspection pit assembly |
GB2299603A (en) * | 1995-04-06 | 1996-10-09 | C I S | Manhole cover |
GB2360807A (en) * | 2000-04-01 | 2001-10-03 | Atlanta Impex Ltd | Access Cover Component and Assembly |
EP1229173A1 (en) * | 2001-02-06 | 2002-08-07 | Karl Kortmann | Cover device for pipes, particularly man-holes |
JP2002348895A (en) * | 2001-05-23 | 2002-12-04 | Asahi Tec Corp | Underground structure cover |
US20040042849A1 (en) * | 2002-08-15 | 2004-03-04 | Bescal, Inc. | Utilities access closure |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2468480A (en) * | 2009-03-06 | 2010-09-15 | Wrekin Welding & Fabrication E | Ground surface access assembly with reinforcements |
EP2246483A1 (en) * | 2009-03-06 | 2010-11-03 | Wrekin Welding & Fabrication Engineering Limited | Ground surface access assemblies |
GB2468480B (en) * | 2009-03-06 | 2014-01-08 | Wrekin Holdings Ltd | Ground surface access assemblies |
CN114150706A (en) * | 2021-11-29 | 2022-03-08 | 安徽省飞龙新型材料有限公司 | Deformable dual-purpose manhole cover and using method thereof |
Also Published As
Publication number | Publication date |
---|---|
EP1752584A3 (en) | 2008-05-14 |
GB0515846D0 (en) | 2005-09-07 |
GB2429228B (en) | 2011-03-30 |
GB2429228A (en) | 2007-02-21 |
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