GB2102048A - Surface box lid assembly - Google Patents

Abstract

A lid assembly, suitable for fitting as a replacement for a damaged hinged lid of a surface box, locks to the surface box body by means of a locking member 12 which engages under an internal abutment of the body, e.g. the internal flange on which the lid 1 seats. The locking member 12, made of plastics, has a flexible oval hub 13 from which detainer elements 14 project for engagement under the abutment. A cam member 15 having a complementary part engaging in the hub 13 can be revolved, by a key inserted through a key hole in the lid, between positions in which the complementary part is respectively aligned with and out of alignment with the hub. In the aligned position the detainer elements 14 can engage under the abutment. In the non-aligned position the resultant distortion of the hub draws the detainer elements towards the revolving axis of the cam member to inoperative positions which allow the lid assembly to be fitted to and removed from the body. <IMAGE>

Description

SPECIFICATION Improvements relating to surface boxes This invention relates to surface boxes such as are used in conjunction with water, sewage, gas, electrical and telephone services to gain access, for example, to conduits, taps, controls or cables.

It has been usual hitherto for surface boxes to have hinged lids which are swung open, possibly with the aid of a lifting iron, to gain entry into the bodies of the boxes. The lids are hinged by means of hinge pins, most commonly of metal, retained to the bodies of the boxes.

A problem with this known arrangement is that, because of the manner in which the hinge pins are connected to the lids and retained to the bodies of the boxes, it has often been necessary to replace the complete surface box when the lid has become worn or has been damaged, or the hinge pin has become excessively corroded or has been broken. It is the lids of the surface boxes which are most prone to wear or liable to be broken, because they are exposed at the points of installation of the surface boxes. It can be a difficult, time consuming, and thus costly, exercise to remove a complete surface box from its installation because usually the box has to be excavated out of the installation point.

The present invention seeks to provide a lid assembly which can be readily removed from a surface box body, and may be fitted as a replacement for a hinged lid.

According to one aspect the present invention consists in a lid assembly adapted to be fitted to the body of a surface box, comprising the lid proper which is adapted to locate in or over the entrance of the body and has a key hole extending through it, and retained to an inner part of the lid locking means which comprises a hub element opposite the key hole and a detainer element which projects laterally from the hub element parallel, or generally parallel, to the lid and is adapted releasably to co-operate with an abutment face of the body directed away from the entrance of the body, the hub element being operable by a key inserted through the key hole from the outside of the lid to cause the detainer element to be moved from a locking position to a released position, and the arrangement being such that when the assembly is fitted to the body of a surface box the detainer element engages in its locking position with the abutment face of the body and locks the assembly to the body with the lid closing the entrance of the body, and the detainer element can be moved by means of the key to the released position in which it is disengaged from the abutment face and the assembly is able to be separated from the body.

According to a further aspect the present invention consists in a surface box comprising a body having an entrance and an abutment face or faces internally thereof spaced from and directed away from the entrance, and a lid assembly as set forth which is located in or over the entrance of the body and the detainer element or elements releasably co-operate with the abutment face or faces to lock the lid assembly to the body with the lid closing the entrance.

It is the locking means which retains the lid assembly to the body of the surface box. Thus the troublesome hinged connections of the previously known surface box lids are avoided. Release of the lid assembly for entry into the body is effected readily by means of the key.

Preferably the hub and detainer elements are made of a suitable plastics material which avoids any possibility of their corroding when in use and making the locking means difficult to operate.

It is usual for the bodies of surface boxes to have either internal ledges on their walls inset from the entrances, or internal webs or flanges inset from the entrances at the sides or extending across corners of the bodies. When the lid of the lid assembly now provided is adapted to locate in the entrance of the body of a, or the, surface box it is convenient for it to seat on such a ledge or on such webs or flanges. In the known surface boxes having hinged lids and bodies formed with internal ledges, the ledges are not provided on those walls of the bodies which are adjacent and parallel to the hinge axes of the lids, and in the cases where the bodies have webs or flanges the webs or flanges are provided on the walls other than those which are adjacent and parallel to the hinge axes of the lids, or across those corners of the bodies which are remote from the hinge axes of the lids.

For use with a body of either of these forms the lids of the present lid assembly may be provided with one or more projections on its inner face, adjacent to one side of the lid, adapted to extend into the body adjacent to the wall which does not have the ledge, or the webs or flanges. The projection or projections may rest on a suitable support in or associated with the body when the body is installed for use such that the side of the lid which is not supported by the internal ledge, or by the web or flanges, of the body is supported by means of the seating projection or projections, and the lid cannot be tilted on the body, at least whilst the locking member is locked.Commonly the body of a surface box when installed seats at its end opposite to the entrance on the end of a pipe, sleeve or chamber of a diameter complementary to the width of the body so that segments of the end of the pipe, sleeve or chamber extend across the corners of the end of the body and are exposed to the interior of the body. The projection or projections on the lid may be adapted to rest on the end of the pipe, sleeve or chamber at the appropriate segments.

The lid may alternatively have a hook or hooks at its inner face adapted to engage under the ledge, web or flanges at the wall of the body opposite to that wall which does not have the ledge, web or flanges, and at least one projection at its inner face which extends into the body adjacent to the last-mentioned wall of the body.

The hook or hooks by their engagement under the ledge, web or flanges restrain the lid from being tilted on the body, and the projection or projections restrain the lid from being moved laterally of the body in the direction of the wall adjacent to which the or each projection is disposed, and thereby prevent the hook or hooks from being disengaged from under the ledge, web or flanged by such movement.

There may be more than one detainer element projecting laterally from the hub. There may, for example, be two diametrically opposed detainer elements which are adapted to engage in their locking positions with abutment faces at opposite sides of the body.

The abutment face or faces may be provided by a part or parts of the face of the end of the body opposite to the entrance end of the body. When the body has an internal ledge for the lid to seat on formed by an internal flange the undersurface of the flange may alternatively provide the abutment face or faces.

In a preferred form of the locking means the hub element is flexible and has a non-circular hollow or aperture in which the key is able to engage. The key is movable in the hollow or aperture between a first position in which the key is a free fit in the hollow or aperture and the or each detainer element occupies one of the locking and released positions, and a second position in which the key engages with interference in the hollow or aperture and causes the hollow or aperture, and thereby the hub, to distort and cause the or each detainer element to occupy the other one of the locking and released positions. The hollow or aperture may be of oblong cross-section in which case the detainer element may project from the hub adjacent one end of the oblong cross-section.Where there are two diametrically opposed detainer elements and the hollow or aperture is of oblong cross-section the detainer elements preferably extend from adjacent the opposite ends of the longitudinal axis of the hollow or aperture. When turned the key is arranged to cause the walls of the hub element at opposite sides of the longitudinal axis of the hollow or aperture to be urged outwardly with the result that the walls adjacent the opposite ends of the longitudinal axis are drawn inwardly and move the detainer element or elements inwardly with them. The normal outward position which the or each detainer element can occupy can be the locking position of the detainer element, and the inward position can be the released position.The key may act directly on the walls of the hub element, or it may co-operate with a cam which engages with the walls to urge them outwardly.

The resilience of the hub element automatically returns the or each detainer element to the outward locking position when the key is turned to a position in which the walls of the hub element are not distorted by the key or cam. In this preferred form the hub and detainer elements are conveniently made as integral parts of a one-piece member which conveniently is a moulding of a suitable plastics material.

The key may be a standard lifting iron so that it does not have to be specially made for the assembly. It may, however, be of other suitable forms, if desired, although that would generally add to the cost of the assembly.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a plan view of a lid assembly in accordance with the present invention; Figure 2 is a section on line 2-2 of Figure 1; Figures 3 and 4 are respectively inverted plan and side views of a lid and stem of the assembly; Figure 5 is an underneath plan view of a locking member and cam of the assembly; and Figure 6 is an exploded perspective view of a further form of lid assembly in accordance with the invention.

in these embodiments the lid assembly is intended to be fitted to a standard form of surface box body as used, for example, to provide access in roads and pavements to stop taps of water services. Such a body, which may be of metal or plastics, is rectangular having four side walls and being open at opposite ends, the one end forming the entrance into the body and the other having an external flange which serves to anchor the body securely in position when installed for use. An internal flange inset from the entrance end of the body provides a ledge which extends around three of the walls of the body. The other wall, which would normally be the one adjacent to which a hinged lid would be hinged, has a plain internal surface. When installed the body would normally seat on the upper end of a pipe, sleeve or chamber in the manner previously described.

Referring now to the embodiment as illustrated by Figures 1 to 5 of the drawings, the lid assembly comprises a unitary metal, for example cast iron, casting or plastics moulding, for example of polyvinyl chloride, which includes a substantially rectangular lid 1, Figures 1 and 2, dimensioned to locate inside the entrance end of the body on the internal flange, indicated at F in Figure 2, a stem 2, Figures 3, 4 and 5, depending centrally from the lower, inner face of the lid, and two seating projections 3, Figures 3 and 4, which also depend from the inner face of the lid near to two adjacent corners of the lid. The lid 1 is of slab form and may have a tread pattern on its upper, outer, face. The seating projections 3 are of strip form depending diagonally with respect to the adjacent end corners of the lid. The stem 2 has a generally H-shaped cross-section with a considerably thickened transverse portion which forms the main body 4 of the stem. A key hole 5 extends axially of the stem 2 through the lid. The key hole 5 has a modified regular oval cross-section enlarged to a part-cylindrical shape at its central portion. The longitudinal axis of the cross-section of the key hole extends parallel to the opposite sides of the H-section of the stem. A recess 6 is formed in the stem 2 of a part-cylindrical shape which is co-axial with the stem and larger in diameter than the length of the cross-section of the key hole. The recess 6 breaks through the opposite sides of the stem. Aligned channel section grooves 7 are formed in the bottom end face of the stem and open radially into the recess from the opposite ends of the H-section of the stem.Near their opposite ends the leg portions of the H-section of the stem are thickened by partcylindrical rib formations 8, Figure 3, and in those thickened portions blind plain bores 9 for screws are formed in the bottom end of the stem.

A plastics retainer plate 10, of generally rectangular shape of length corresponding to the length of the H-section of the stem, is secured to the bottom of the stem by self-tapping screws, not shown, passed through holes in the plate and tightened into the blind bores 9. Two drain holes 11 are provided in the retainer plate.

A locking member 12 is retained to the stem by the retainer plate 10. The locking member is a one-piece plastics moulding which comprises a hollow, symmetrical oval hub element 13, Figure 5, and two blade-like detainer elements 14 which are joined to and project in diametrically opposite directions from the ends of the oval shape of the hub 13. The peripheral wall of the hub is flexible.

The detainer elements have sufficient thickness to be substantially rigid. The hub 13 fits in the lower part of the recess 6 of the stem and the detainer elements slidingly engage in the grooves 7 and project from the opposite ends of the H-section of the stem.

Also located in the recess 6 is a cam member 1 5 moulded from plastics material. This member has a cylindrical upper part 16 which is complementary to the recess and an oval-section lower part 17, Figure 5, which is generally complementary to and fits inside the hub 13 of the locking member. The fit of the cam member 1 5 in the recess is such, and the co-operation between the cam member and hub is such, that with the retainer plate 10 secured to the stem movement of the cam member and locking member axially of the stem is prevented. The cam member can, however, revolve in the recess, the hub being sufficiently flexible to allow the oval lower part 1 7 to turn in the hub. The engagement of the detainer elements in the grooves 7 restrains the locking member from rotation with the cam member.An extension of the key hole 5 is formed, as at 18, in the cam member. The cam member has a web 19, Figures 2 and 5, which extends across the enlarged central portion of the key hole extension 1 8 adjacent the bottom of the member. The bottom of the key hole extension 1 8 is closed off by the retainer plate. A ring of lightening holes, not shown, is also formed in the cam member longitudinally of the member.

The retainer plate 10, locking member 12 and cam member 1 5 are preferably formed from a polyacetal plastics.

Since the lower part 17 of the cam member is of generally complementary shape to the hub, as the cam member is revoved away from alignment with the hub it causes the hub to distort, forcing the side portions of its wall outwardly and thereby causing the end portions to be drawn inwardly so that the detainer elements are also drawn radially inwardly, A key, not shown, for operating the locking member may be formed by a standard lifting iron which comprises a shank of round-section metal bar formed into a handle at one end and having a cross-piece of flat metal strip spliced into and welded to its opposite end. The key can be inserted into the key hole and key hole extension 1 8 of the cam member to engage the cross-piece of the key in the key hole extension in order to rotate the- cam member.The web 1 9 acts as a stop with which the key engages when it is properly inserted in the cam member.

For fitting the lid assembly to an installed surface box body as previously described, the cam member is turned by the key to a position in which its oval-section lower part 1 7 is disposed transversely in the hub 1 3 of the locking member and hence the detainer elements are fully withdrawn to an inoperative position. The stem is then inserted into the body until the lid is seating on the internal flange F and the seating projections 3 are resting on segments of the end of the pipe, sleeve or chamber next to the bottom of the plain wall of the body.Upon then turning the key to revolve the cam member so that its lower part 1 7 is brought back into alignment with the hub the detainer elements move outwardly to their normal projecting, locking positions and engage under the flange F at opposite side walls of the body, and thereby prevent the lid assembly from being removed from the body. Whilst the assembly is thus locked the seating projections 3 prevent the lid from being tilted on the body and access being gained into the body in that manner. The subsequent removal of the key without revolving the cam member, which is possible because the key hole extension 1 8 is fully in register with the key hole 5 in the stem when the lower part of the cam member is aligned with the hub, leaves the lid locked to the body. Release is possible only by means of the key.

The further embodiment illustrated by Figure 6 of the accompanying drawings will now be described. Parts of the lid assembly which correspond to those of the embodiment just described are identified by corresponding reference numbers.

The lid 1, which again is of substantially rectangular shape arranged to locate inside the entrance end of the surface box body, is made as a casting of cast iron. Instead of the stem 2, the lid has two block-like protrusions 20 formed integrally with it on its upper face. The protrusions 20 are equally spaced at opposite sides of the central axis of a key hole 5 centrally formed in the lid and of similar shape to that of the key hole in the first-described embodiment. Directly opposed faces 21 of the two protrusions 20 are particularly curved concavely, the radius of curvature being the same for both faces and the centre of the curvature lying on the central axis of the key hole 5.These curved, opposed faces 21 and the portion of the inner face of the lid between the protrusions define a recess 6 of part-cylindrical shape corresponding to the recess in the stem of the first-described embodiment. Aligned channelsection grooves 7 are formed in the bottom end faces of the protrusions and open radially into the recess 6. Plastics channel section guides 22 of complementary depth, width and length to the grooves 7 are located in the grooves. Peg formations 23 on the web-portions of the guides 22 are a tight push fit in complementary sockets 24 in the grooves 7 to retain the guides in the grooves.

A cam member 1 5 is rotatably located in the recess 6 and is of substantially similar form to the cam member of the previous embodiment having an oval-section lower part 17. The cam member has a key hole extension, not shown, in it which is co-axial with and of corresponding shape to the key hole 5 in the lid. At the bottom of the cam member the key hole extension reduces to a narrow slot 25 with enlarged circular ends 25'.

The slot extends along the major diameter of the oval-section lower part 1 7 of the cam member.

A locking member 12 of similar shape to that of the previous embodiment made as a one-piece plastics moulding has its oval hub portion 13 engaged by the complementary lower part 17 of the cam member, and its diametrically opposed, blade-like detainer elements 14 slidingly engage in the guides 22 in the protrusions 20. The detainer elements extend towards two opposite sides of the lid. The cam member is retained in the recess, and the locking member is retained in engagement with the cam member and guides, by means of a rectangular retainer plate 10 secured across the recess and the bottoms of the protrusions by screws 26 which pass through holes in the plate and screw into tapped holes 27 in the protrusions. An oblong drain hole 11 is formed in the retainer plate 10.As before, the hub 1 3 of the locking member 12 is sufficiently flexible to allow the hub to distort as the cam member is revolved out of alignment with the hub and cause the detainer elements to be drawn radially inwardly to an inoperative position.

As in the previous embodiment, the cam member 15, locking member 12 and retainer plate 10 are preferably formed of a polyacetal plastics, and the guides 22 are also preferably formed of that material.

The cam member is revolved by means of a key of the form previously described. Alternatively it may be revolved, for example in an emergency when a key is not available, by means of a screwdriver or like tool by inserting the tool in the key hole and cam member and engaging its driving end in the narrow slot 24.

Depending from the inner face of the lid 1 near to a third side of the lid are two L-shaped hooks 28 which are disposed with their foot portions 29 extending parallel to one another towards the third side of the lid. Adjacent to the opposite, fourth side of the lid there is a central lug 30 which also projects from the inner face of the lid. The hooks 28 are adapted to engage under the internal flange at that side wall of a surface box body which is opposite to the side wall adjacent to which a conventional lid would be, or would have been, hinged, and the lug 30 is adapted to project into the body close to the last-mentioned side wall of the body.

For fitting the lid assembly to a surface box body the cam member is turned, as before, by a key to a position in which the detainer elements are in the inoperative position in which they are fully withdrawn. The lid is inserted in the entrance of the surface box body by tilting its said third side downwards and engaging the hooks 28 under the internal flange at the one side wall of the body, and then swinging the said fourth side of the lid downwards until the lid closes off the entrance.

That movement enters the lug 30 into the body adjacent to the opposite side wall of the body.

When the lid fully closes the entrance it seats squarely on the internal flange of the body. The cam is then turned by the key to engage the detainer elements under the internal flange at the other side walls of the body and so lock the lid to the body. When the lid is locked the engagement of the hooks with the internal flange prevents the lid from being tilted on the body, and the hooks and lug 30 together prevent the lid from being slid on the body in the direction of either of the adjacent two side walls. Hence there is no possibility of manoeuvring the lid out of engagement with the surface box body unless the cam has first been revolved to release the detainer elements from locking engagement with the internal flange of the body.

It will be appreciated that in each of the embodiments described the lid assembly can be readily fitted to an existing surface box body to replace a hinged lid removed from the body.

Claims (21)

1. A lid assembly adapted to be fitted to the body of a surface box, comprising the lid proper which is adapted to locate in or over the entrance of the body and has a key hole extending through it, and retained to an inner part of the lid locking means which comprises a hub element opposite the key hole and a detainer element which projects laterally from the hub element parallel, or generally parallel, to the lid and is adapted releasably to co-operate with an abutment face of the body directed away from the entrance of the body, the hub element being operable by a key inserted through the key hole from the outside of the lid to cause the detainer element to be moved from a locking position to a released positiOn, and the arrangement being such that when the assembly is fitted to the body of a surface box the detainer element engages in its locking position with the abutment face of the body and locks the assembly to the body with the lid closing the entrance of the body, and the detainer element can be moved by means of the key to the released position in which it is disengaged from the abutment face and the assembly is able to be separated from the body.

2. A lid assembly according to Claim 1 wherein a plurality of the detainer elements is provided and each of the detainer elements projects laterally from the hub element.

3. A lid assembly according to Claim 2 wherein there are two detainer elements which are diametrically opposed and adapted to engage in their locking positions with abutment faces at opposite sides of the body.

4. A lid assembly according to any preceding claim wherein the or each detainer element is caused to be moved linearly by the hub element between the locking and released positions.

5. A lid assembly according to Claim 4 wherein the hub element is flexible and has a non-circular hollow or aperture in it in which the key is able to engage and in which the key is movable between a first position in which it is a free fit in the hollow or aperture and the or each detainer element occupies one of the locking and released positions, and a second position in which the key engages with interference in the hollow or aperture and causes the hollow or aperture, and thereby the hub, to distort and cause the or each detainer element to occupy the other one of the locking and released positions.

6. A lid assembly according to Claim 4 wherein the hub element is flexible and has a non-circular hollow or aperture in it in which is a cam with which the key co-operates, the cam being movable by the key between a first position in which the cam is inoperative and the or each detainer element occupies one of the locking and released positions, and a second position in which the cam engages with interference in the hollow or aperture and causes the hollow or aperture, and thereby the hub, to distort and cause the or each detainer element to occupy the other one of the locking and released positions.

7. A lid assembly according to either one of Claims 5 and 6 as dependent from Claim 1 wherein the hollow or aperture is of oblong crosssection and the detainer element projects from the hub adjacent one end of the oblong crosssection.

8. A lid assembly according to either one of Claims 5 and 6 as dependent from Claim 3 wherein the hollow or aperture is of oblong crosssection and the detainer elements project from the hub adjacent the opposite ends of the oblong cross-section.

9. A lid assembly according to any of Claims 6 to 8 wherein the hub and detainer elements are integral parts of a one-piece member.

10. A lid assembly according to Claim 9 wherein the one-piece member is a plastics moulding.

11. A lid assembly according to any preceding claim wherein the or each detainer element cooperates with a guide rigid with the lid which guides the detainer element in its movement between the locking and releasing positions.

12. A lid assembly according to any preceding claim wherein a stem extends from an inner face of the lid, and the hub element and the or each element are retained to the stem.

13. A lid assembly according to Claim 12 wherein the stem is formed in one with the lid.

14. A lid assembly according to Claim 12 or Claim 13 wherein the hub element is accommodated in a recess in the stem opening to the end of the stem remote from the lid, the or each detainer element is engaged in a guide groove in the stem extending laterally from the recess and projects laterally from the stem, and a retainer element secured to the remote end of the stem retains the hub element in the recess and the or each detainer element in its guide groove.

1 5. A lid assembly according to Claim 11 wherein there is a plurality of the detainer elements, there is a corresponding number of protrusions on an inner face of the lid which together define a recess accommodating the hub element and each of which has a guide groove in its end remote from the lid in which a respective one of the detainer elements is engaged, the detainer elements projecting laterally beyond the protrusions, and a retainer element is secured to the remote ends of the protrusions and retains the hub element in the recess and the detainer elements in the guide grooves.

1 6. A lid assembly according to any preceding claim wherein the lid has at least one projection on an inner face thereof which is disposed adjacent an edge of the lid and is adapted to extend into the body of a surface box adjacent a wall thereof to assist the locking means in restraining movement of the lid relative to the body of the surface box when the locking means is operative.

17. A lid assembly according to Claim 16 wherein the or each projection is adapted to seat on a support in or associated with the body of the surface box when the body is installed for use.

18. A lid assembly according to Claim 16 wherein one or more hooks are provided at the inner face of the lid adjacent an edge of the lid opposite to that adjacent to which the or each projection on the lid is disposed, the hook or hooks being adapted to engage under an internal projection or projections at a side wall of the body of the surface box, the arrangement being such that when the lid is located in or over the entrance of the body of the surface box the or each hook by its engagement with said internal projection or projections of the body restrains the lid from being tilted on the body, and the or each projection on the lid restrains the lid from being moved laterally of the body in the direction of the wall adjacent to which the projection is disposed and thereby prevents the hook or hooks from being disengaged from under said internal projection or projections of the body by such movement.

19. A surface box comprising a body having an entrance and an abutment face or faces internally thereof spaced from and directed away fr.om the entrance, and a lid assembly as claimed in any preceding claim which is located in or over the entrance of the body and the detainer element or elements releasably co-operate with the abutment face or faces to lock the lid assembly to the body with the lid closing the entrance.

20. A lid assembly substantially as described herein with reference to and as illustrated by Figures 1 to 5 of the accompanying drawings.

21. A lid assembly substantially as described herein with reference to and as illustrated by Figure 6 of the accompanying drawings.