EP3775396B1

EP3775396B1 - A ground surface access assembly frame

Info

Publication number: EP3775396B1
Application number: EP19730878.6A
Authority: EP
Inventors: Barry Turner; Samantha Sarah Elizabeth Evans; Liam Mark Ratcliffe; Simon John Gibson; Stanley Turner; Paul Drummond NIELSON; Simon John TURNER
Original assignee: Wrekin Holdings Ltd
Current assignee: Wrekin Holdings Ltd
Priority date: 2018-03-30
Filing date: 2019-05-20
Publication date: 2024-04-03
Anticipated expiration: 2039-05-20
Also published as: GB2572445B; GB2572445A; EP3775396A1; WO2019186212A1; GB201805327D0

Description

Technical Field

This invention relates to a ground surface access assembly comprising an opening cover and supporting frame, and in particular to the configuration of the frame.

Background Art

Ground surface access assemblies are typically used in road drainage systems, for example, to provide covered access to an underground chamber. Such assemblies principally comprise a mounting frame and a cover that is removable or opening. These assemblies have to withstand heavy loads and impacts as vehicles drive over them. They are typically bedded upon the upper surfaces of an underground chamber by a layer of fast-setting bonding material some of which is poured around and over the frame base portion. The bedding around the base portion of the mounting frame is particularly vulnerable to damage, typically cracking, as a result of these heavy loads and impacts. Known assemblies rely heavily upon the adhesion between the planar faces of the frame base portion and the encapsulating bonding material. Unfortunately, the external surfaces of the frame base portion are often coated in a paint or bitumen type material, which severely compromises the bond with the encapsulating materials. Thus, under load, detachment of the frame, and in particular the base portion, often occurs, due to lack of adhesion. This is then typically followed by unrestrained frame movement, which severely damages the bedding material and normally requires re-installation or replacement of the ground surface access assembly. Further, the base portion of the frame may (if not sufficiently restrained) flex under load due to lack of rigidity. While the bedding or encapsulating material will initially provide such restraint, such flexing will impose undesirable multiple-direction stresses upon the bedding/encapsulating material.
GB2359319A (SAINT-GOBAIN PIPELINES PLC) discloses a frame for supporting a manhole cover where the outer flange (30) has a plurality of grooves located on the flange corners, provided to stiffen the frame and, to enhance anchoring of the flange in a bedding material.
JP 2000 144779A (KUSATAKE SUGIAKI) provides a cover receiving frame with a collar edge (5), which in use, presents an upper exposed non-slip surface of the frame (1), with the aim of reducing user slippage when installed.
An aim of the present invention is to provide a ground surface access assembly support frame that is configured to provide improved adhesion to surrounding bedding/encapsulating material, following installation; and in particular to restrain lateral movement of the base relative to the bedding/encapsulating material, in all directions. A further aim is to provide a support frame that provides interlock between the frame sides and the surrounding bedding/encapsulating material. Another aim is to provide frame with a base portion that is configured to reduce the possibility of cracking and subsequent break-up of the bedding material when subjected heavy loads and impacts from vehicles passing there over. A further aim is to provide a support frame that has improved rigidity and will be less likely to deform when subjected to high loads and impacts.
The aims of the present invention are achieved by independent claim 1.
According to the invention, said smooth protrusions have no sharp edges, and preferably said protrusions comprise a smooth valley portion and a smooth peak with a smooth transition there-between.
Preferably, the location of the protrusions on the support frame are offset (from a regular matrix) in such a way as to avoid straight paths around sides of the protrusions.
Preferably, the upper surface of said base plate/flange of the support frame has many closely adjacent protrusions with no sharp edges that extend outwardly therefrom; such that following installation said protrusions provide improved adherence of the base plate to structural infill bonding material.
Preferably, the support frame further comprises a base plate flange having a series of upstanding flange-portions that define a crest each of which is separated from an adjacent crest by an intermediate valley flange-portion and wherein said closely-spaced smooth projections are located on the upper surface of said upstanding crest. Preferably, the valley flange-portion comprises a substantially flat flange portion. The upstanding crest may comprises two angled planar flange portions
According to the invention, the outer surface of said inclined sidewall of the support frame and/or the upper surface of a flange portion of the support frame has many smooth protrusions, with no sharp edges; such that following installation said smooth protrusions provide improved adherence of the base plate to structural infill bonding material while avoiding stress induced cracks propagating, in the infill bonding material, from said protrusions when the installed ground surface access assembly is subject to severe or repetitive loads/shocks
In a second aspect the invention comprises: a ground surface access assembly support frame surrounding and defining an aperture, and a cover member dimensioned to substantially seal said aperture; said support frame comprising a base plate and flange portion thereof having a series of upstanding crests each of which is separated from an adjacent crest by an intermediate valley portion. Preferably, the valley portion comprises a substantially flat floor portion.
Preferably, the support frame further comprises a reinforcement member/gusset that extends downwardly from the outer surface of a short cylindrical sleeve portion of the frame adjoining and being supported by the peak of crest. Preferably, the upstanding crest comprises two angled planar surfaces connected by a curved peak. Preferably, the lower/underside surfaces of the two planar faces are inclined at an obtuse angle to each other. Preferably, the obtuse angle is in the range 100° to 170°. More preferably the obtuse angle is in the range 120° to 150°.
Preferably, either the upper surfaces of the substantially flat portions and/or the intermediate upstanding crests have many closely adjacent protrusions with smooth surfaces that extend outwardly/upwardly therefrom; and that following installation provide an interlock with structural infill material.
Preferably, the upper surface of an inclined sidewall of the support frame or the outer surface of a flange portion of the support frame have many smooth protrusions with smooth surfaces that extend outwardly; such that following installation said protrusions provide an interlock with structural infill material.
Preferably, the protrusions on the frame are not centred on a rectangular matrix, but rather are offset in such a way as to avoid straight paths around sides of the protrusions.
In a third aspect the invention comprises: a ground surface access assembly support frame surrounding and defining an aperture; and a cover member dimensioned to substantially seal said aperture; where the upper surface of the base plate of said support frame has many closely adjacent protrusions with smooth surfaces that extend outwardly therefrom; such that following installation said protrusions provide an interlock with structural infill material.
In a fourth aspect the invention comprises: a ground surface access assembly support frame surrounding and defining an aperture; and a cover member dimensioned to substantially seal said aperture; where the upper surface of an inclined sidewall of the support frame and/or the outer surface of a flange portion of the support frame has many smooth protrusions with smooth surfaces that extend outwardly; such that following installation said protrusions provide an interlock with structural infill material.
In all of the above aspects of the invention; preferably the minimum separation distance between adjacent protrusions is in the range 0.5D to 5D, where D is the maximum length of the protrusion; and more preferably in the range 0.5D to 2D
Optionally, in all of the above aspects of the invention, adjacent protrusions provide a generally semi-spherical upper surface or a partially or semi-ovoid upper surface.
Advantageously, in all of the above aspects of the invention, the smooth surface of the protrusions has been found to deter the initiation of cracks in the bedding material etc., which may occur when the installed ground surface access assembly is subject to severe loads or shocks that periodically occur in use.
The invention also comprises a method of installing a ground surface access assembly according to claim 9.
Brief Description of Drawings
The present invention is illustrated by the following diagrammatic figures in which:

Figure 1 shows a perspective view of a ground surface access assembly according to a preferred embodiment of the present invention;
Figure 2 shows the assembly of Figure 1 with the circular cover detached from the support frame, in which it is normally housed, and positioned (horizontally) above the support frame;
Figure 3 shows an underside perspective view of the ground surface access assembly of Figure 1;
Figure 4 shows an underside plan elevation of the ground surface access assembly of Figure 1;
Figure 5 shows a cross sectioned perspective view along the line X-X' of Figure 4;
Figure 6 shows a diametric cross sectioned side elevation of the ground surface access assembly of Figure 1;
Figure 7 is similar to Figure 6, but shows the circular cover lifted clear of the support frame;
Figure 8 shows an underside perspective view of the circular cover of the ground surface access assembly of Figure 1;
Figure 9 is an enlarged view of part of the frame base portion of Figure 1 showing upstanding crests with many distributed smooth protrusions thereon;
Figures 10a to 10 show cross sections of smooth protrusions in accordance with the present invention; and
Figure 11 is an enlarged view of part of the frame base portion of Figure 3 showing in particular the underside surface of individual crests including generally corrugated surfaces located in recessed areas.

Detailed Description

Figures 1 to 7 and 9 to 11 illustrate a preferred embodiment of a ground surface access assembly support frame (12) according to the present invention.
In particular, Figure 1 illustrates a ground surface access assembly (10) comprising a square (with rounded corners) support frame (12) with a short cylindrical sleeve (14) that defines a circular aperture configured to house a circular cover (16). In this embodiment an extension portion (20) of the circular cover (16) is detachably mounted within a hinge mount assembly (18); allowing the cover to be pivoted about a pivot member (22) seated within a linear recess (24) that has a curved lower portion configured to match the curvature of the pivot member (22) surface. In use, this combination allows the cover to be moved (pivoted) from the position as illustrated in Figure 1 to an open position, where the upper surface of the circular cover (16) is positioned approximately perpendicular to the base-plate/flange portion (26) of the support frame (12); allowing removal of the circular cover (16) from the support frame (12) by lifting upwardly.
The extension portion (20) is approximately rectangular (in plan view); a first end extends outwardly from the flange sidewall (28) of the cover; and a second end is connected to the pivot member (22). In this embodiment the hinge mount assembly (18) is integrally formed with the short circular sleeve (14) and the frame baseplate/flange portion (26) of the support frame (12).
While the present embodiment illustrates a frame base portion (26) that is square with rounded corners in outline (in plan view) the shape may vary; for example, according to the present invention the base portion may be rectangular with rounded corners or circular in outline. Also, the hinge mount assembly may extend outwardly from the flange sidewall (28) without being connected to the frame base portion (26).
The circular cover (16) also has an aperture (32) located within the planar surface in a position diametrically opposite the hinge members (20, 22, 24); configured to operably engage a standard lifting key - that in use assists an operative when opening and removing the circular cover. That part of the flange sidewall (28) proximate the key aperture (32) also has a locking assembly housing (34) integrally formed with the short circular sleeve (14) and frame base portion (26). The locking assembly housing (34) may extend outwardly from the flange sidewall (28) without being connected to the base portion (26). A locking plate (36), integrally forming part of the circular cover, extends outwardly from the cover flange and cooperates with the locking assembly housing (34) to allow the circular cover to be secured/locked in place when not open for inspection.
Figure 2 shows the ground surface access assembly (10) of Figure 1 with the circular access cover (16) detached, and located slightly above the normally surrounding support frame (12).
The rectangular frame base portion (26) has a pair of securing apertures (48) proximal each corner. The short cylindrical sleeve (14) extends downwardly to join an inclined sidewall (46) and this sidewall also extends downward to join the frame base portion (26). Typically, the short cylindrical sleeve (14); the inclined sidewall (46); and the frame base portion (26) are integrally formed.
The outer surfaces of the inclined sidewall (46) and frame base portion (26) are divided into separate portions/sections by a series of radially extending and integrally formed reinforcement members (44). As the inclined sidewall (46) bridge the short circular sleeve (14) and frame base portion (26) - that in plan view are circular and square with rounded corners in outline, it follows that the outer surface area of individual portions of the inclined sidewall (46) vary accordingly. In the illustrated embodiment the reinforcement members (44) have curved cross sections (see Figure 6). The sidewall (46) is typically inclined at an acute angle (typically of 10-60°) to the plane of the base portion/plate (26).
The raised position of the circular access cover reveals further details of the cover portion of the hinge mount assembly (18), in particular extension portion 20 and pivot member 22. Likewise, Figure 2 also shows further details of the circular cover locking system; the locking plate (36) that extends outwardly from the flange of the circular cover has a central aperture (38) and a pair of downwardly extending flexible arms (40) with integral inwardly-facing protrusions that in use engage internal members of the locking assembly housing (34).
Figure 3 shows an underside perspective view of the surface access assembly (10) of Figure 1; Figure 4 shows an underside plan elevation of the ground surface access assembly of Figure 1; and Figure 5 shows a perspective cross sectioned view of Figure 4 along line X-X'.
The underside of the circular cover is reinforced by a beam that is annular (when viewed from above or below - plan view); has a beam cross section that is substantially a "L-section, and is integrally formed within the overall structure of the circular cover. This circular beam (60) is illustrated in Figure 3, and the "L- shaped" cross section is shown in the cross sectioned view of Figure 5. As the reinforcement member (60) comprises a continuous angled and circular beam it has no end faces, but. The "L- shaped" cross section comprises: a first vertical planar section (62) that adjoins the underside surface of main body portion (30); of the cover (16); a second planar section (64); and an intermediate section (63); where first and second planar sections (62, 64) join at right angles to each other. The second planar section (64) extends inwardly towards the geometric centre of the cover (16) and is generally parallel to the plane of the upper and lower surfaces of said main body portion (30).
The circular cover (16) member and the circular reinforcement beam (60) portion thereof, are typically cast as a single entity, from ductile iron using a traditional casting mould.
Thus, the ground surface access assembly (10) comprises a support frame (12) surrounding and defining an aperture; and a cover (16) comprising a main body portion (30) dimensioned to substantially seal the aperture, with a reinforcement member (60) extending downwardly from on an underside surface of the main body portion (30); the reinforcement member (60) comprising a continuous angled beam (having no end faces) that is integrally formed with the remainder of the cover (16). The continuous angled beam is preferably circular, elliptical or rectangular in plan view.
The inner wall (66) of the first vertical planar section (62) of the beam (60) has a plurality of inner adjoining strengthening ribs (68) that radiate radially inwardly to an integrally formed central upstanding ring (70). Likewise, the outer wall (72) of the vertical planar section (62) has a plurality of adjoining outer strengthening ribs (74) that extend radially outwards adjoining an inner peripheral sidewall (52) of the circular cover (16). The inner peripheral sidewall (52) is configured concentric with and close to the flange sidewall (28). Cylindrical and sealed end undercover (50 - see Figure 3) forms part of the lifting key system.
Figure 5 illustrates that the inner face (76) of the short cylindrical sleeve (14) of the support frame (12) has an integrally formed inwardly extending annular ledge (54) that has a generally "L-shaped" cross section. In use, a resilient non-metallic annular-shaped member (56) fits over and substantially covers the annular ledge (54). In normal use the lower end of the cover flange sidewall (28) rests on part of the resilient member (56); and this combination helps absorb any shock load applied by vehicles etc., passing over an installed ground surface access assembly (10).
Figure 6 shows a diametric cross sectioned view of the ground surface access assembly of Figure 1. The circular cover (16) comprises: the flange sidewall (28); inner peripheral sidewall (52); "L-shaped" (in cross section) circular beam (62, 64); inner strengthening ribs (68); outer strengthening ribs (74); and central upstanding ring (70) - typically, all of these form as a single integral casting of ductile iron. Figure 6 also shows in more detail how, in normal use, the circular cover (16) seats within the support frame (12); and, in particular, that the resilient non-metallic member (56) is supported by the inwardly extending annular ledge (54) of the support frame (12). The gap between the frame flange sidewall (28) and the cover inner peripheral sidewall (52) is selected such that the (outer surface of) inner peripheral sidewall (52) is in close proximity to the outer vertical side surface of the resilient member (56); thereby assisting retention of the resilient member (56) in its correct position, as illustrated in Figure 6.
Figure 7 is similar to Figure 6, but shows the circular cover (16) lifted clear of the support frame (12).
Figure 8 shows an underside perspective view of the circular cover (16) of the ground surface access assembly (10) of Figure 1.
Figure 9 illustrates a part of the support frame (12) and in particular how the upper surfaces of the frame base portion (26) and the inclined sidewall (46) are not smooth, but rather include many smooth protrusions (82a, 82b) that may be approximately hemispherical in shape. The protrusions on the frame base portion (26a) are not centred on a rectangular matrix, but rather are offset in such a way as to avoid straight paths around sides of the protrusions. The protrusions (82b) on the sidewall (46) are spaced apart rather more than the protrusions (82a) on the frame base portion (26) and when the inclined sidewall portion (between bordering reinforcement members (44) is smallest (see item 46a of Figure 2) these protrusions (82c) may comprise just a single row. Smooth-shaped protrusions other than hemispheres are also advantageous; for example, the protrusions may be semi-ovoid shaped or pyramid (but with rounded corners rather than sharp corners) shaped.
The purpose of the protrusions (82a, 82b, 82c) is to provide improved bonding between the support frame (12) and the surrounding bonding materials following installation. Importantly, the protrusions (82a, 82b, 82c) have no sharp edges; and in use (unlike surface protrusions having sharp/angular edges) this has been found to result in the bonding between the support frame (12) and the surrounding road surface being less liable to crack when encountering shock loads from vehicles etc. Thus, the protrusions of the present invention provide the advantage of improved adhesion to bonding materials following installation while avoiding the tendency that sharp-edged protrusions have to propagate stress-induced cracking of the bonding material.
Thus, the ground surface access assembly frame support (12) comprises: a support frame where the exterior surfaces of the frame have clusters of many protrusions therefrom; and that following installation provide an interlock with structural infill material.
The smooth exterior surfaces of the adjacent protrusions (82) promote improved interlocking of the frame exterior with bedding material etc., following installation. Unexpectedly, compared with protrusions having sharp/angled surface features, the smooth surface of the protrusions of the present invention, has been found to deter the formation of cracks in the bedding material etc., which may occur when the installed ground surface access assembly is subject to severe loads or shocks that periodically occur in use. Protrusions with sharp edges do not provide this advantageous effect.
Ground surface access assemblies are typically used to access underground chambers and in normal use are supported by underground chamber walls. The chamber walls commonly comprise pre-fabricated stacked chamber sections or engineering bricks. The frame base portion is typically bonded to upper surfaces of the chamber using a fast-setting Cement or Resin-based settable material; which normally surrounds the upper and lower surface of the frame base portion. Above this first layer there are normally two further layers; a second layer comprising a fast-setting Cement-based settable material with aggregate additions as bulk filler; and a third (top) layer comprising a Bitumen-based Asphalt with aggregate additions for durability and skid resistance.
The ground surface access assembly support frame (12) of the present invention is preferably installed using such a three-layer method. During installation the lower surfaces of the support frame (12) base portion (26) are typically bedded upon the upper surfaces an underground chamber by a first layer of fast-setting Cement or Resin-based settable material. This first layer may initially be poured around and optionally over the frame base portion (26) before it is allowed to set hard. Thus, the first layer may also cover all, or part of, the upper surface of the frame base portion.
Following this a second layer of material is applied on top of the first layer, which will surround and bond to at least a major portion of the inclined sidewall (46) of the frame. This second layer typically comprises a fast-setting Cement or Resin-based settable material. The smooth protrusions (82b) on the inclined sidewall (46) advantageously enhance bonding between said second layer and the support frame (12).
Finally, a third (top) layer typically comprising a Bitumen-based Asphalt, with aggregate additions for durability and skid resistance, will surround, and bond to, the flange portion (14) of the frame (12). Optionally, the outer surface of flange portion (14) of the frame may also have many smooth protrusions (not illustrated). Again, this will advantageously enhance bonding of the sleeve portion (14) of the support frame (12) to the surrounding top layer.
It can be seen that the generally square with rounded corners (in outline and in plan view) frame base portion (26) further comprises a plurality of upstanding crests (80) formed by two angled surfaces (84a, 84b) connected by a curved peak (86); these crests (80) are separated by flat areas 26a (apart from the smooth protrusions 82a) of the frame base portion (26) that are located between adjacent crests (80). Such protrusions (82b) preferably also cover the upper surface (84a, 84b, 86) of the upstanding crests (80) in addition the flat areas (26a) - for example located around the securing apertures (48), as shown in Figure 10. The plurality of upstanding crests (80) advantageously results in improved adhesion between the frame base portion (26) and said first layer of encapsulating material (see above).
Figures 10a and 10b show cross sectional views of various protrusions (82) in accordance with the present invention. In these cases there are no sharp edges; rather, the protrusions comprise a smooth valley portion (100) and a smooth peak (101) with a smooth transition there-between. The valley (100) may comprise a flat portion (as shown in Figures 10a and 10c) or just a curved portion (as shown in Figure 10b). The protrusions (82) may comprise a curved semi-circular portion; a semi-elliptical portion; or they may be asymmetrical (about a vertical centre-line), as shown in Figure 10b.
Figure 11 shows an enlarged view of part of the frame base portion of Figure 3, and in particular the underside surface of individual crests (80) comprising generally corrugated surfaces (88) optionally located in recessed areas (90). These recessed areas (90) are located on a major part of the underside of the two angled surfaces (84a, 84b) and the underside of the curved peak (86). The generally corrugated surface (88) therein in this embodiment comprises five half-cylindrical portions (92) located generally side-by-side. In addition Figure 10 shows smooth protrusions (82d) similar or the same as the protrusions (82a, 82b, 82c) on the upper surface; again housed in underside-recessed areas (94) located in said flat areas (26a).
Thus, the support frame (12) comprises a base portion (26) having a series of substantially flat portions (26a) each of which is separated from an adjacent portion by an intermediate upstanding crest (80). Typically, the series of substantially flat portions (26a) and the intermediate upstanding crests (86) are of approximately similar width, although they typically differ in area.
The upstanding crests (80) confer improved rigidity to the base plate member thereby reducing deflection and flexing of the frame when which occur when the installed ground surface access assembly is subject to severe loads or shocks that periodically occur in use. This advantageously, reduces the possibility of such events damaging the bedding and sealant materials surrounding the frame and securing the frame in the desired position in a road surface.

Claims

A ground surface access assembly support frame (12), forming part of a ground surface access assembly (10), said support frame (12) comprising a base-plate/flange (26), and one or more sidewall portions (14,46), wherein an upper surface of said base-plate/flange (26) of the support frame (12) or the outer surface of an inclined sidewall portion (46) of the support frame (12) has a cluster of closely-spaced smooth-surfaced protrusions (82), wherein said closely-spaced smooth-surfaced protrusions (82) have no sharp edges; such that following installation said smooth-surfaced protrusions (82) provide improved adherence of the base plate (26) to structural infill bonding material while avoiding stress induced cracks propagating, in the infill bonding material, from said protrusions, when the installed ground surface access assembly is subject to severe or repetitive loads/shocks.
A ground surface access assembly support frame (12) according to Claim 1 where the locations of the protrusion (82) on the support frame (12) are offset (from a regular matrix) in such a way as to avoid straight paths around sides of the protrusions.
A ground surface access assembly support frame (12) according to any preceding claim where the minimum separation distance between adjacent protrusions (82) is in the range 0.5 D to 5 D, where D is the maximum length of the protrusion.
A ground surface access assembly support frame (12) according to any preceding claim where the adjacent protrusions (82) comprise a generally semi-spherical upper surface.
A ground surface access assembly support frame (12) according to any preceding claim where the adjacent protrusions (82) provide a partially or semi-ovoid upper surface.
A ground surface access assembly support frame (12) according to any preceding claim wherein the support frame (12) further comprises a base plate/flange (26) having a series of upstanding flange-portions (80) that define a crest, each of which is separated from an adjacent crest (80) by an intermediate valley flange-portion (26a) and wherein said closely-spaced smooth projections (82) are located on the upper surface of said upstanding crest (80)
A ground surface access assembly support frame (12) according to Claim 6 where the valley flange-portion (26a) comprises a substantially flat flange portion.
A ground surface access assembly support frame (12) according to Claim 6 or 7 where the upstanding crest (80) comprises two angled planar flange portions.
A method of installing a ground surface access assembly using a ground surface access assembly support frame according to any of Claims 1 to 8.