GB2463666A

GB2463666A - Manhole cover and frame assembly

Info

Publication number: GB2463666A
Application number: GB0817154A
Authority: GB
Inventors: Justin Meese
Original assignee: STEELWAY FENSECURE Ltd
Current assignee: STEELWAY FENSECURE Ltd
Priority date: 2008-09-19
Filing date: 2008-09-19
Publication date: 2010-03-24
Anticipated expiration: 2028-09-19
Also published as: GB0817154D0; GB2463666B

Abstract

A cover and frame assembly 10 in which the cover 12 has a cover surface 18 and is moveable relative to the frame 14 between a closed condition in which the cover closes an opening 16 afforded by the frame and the cover surface faces outwardly of the frame, and an open condition in which the opening is substantially unobstructed by the cover, the assembly including a retaining structure 25 for retaining the cover in the closed condition, the retaining structure including a first engagement formation 20, and a second engagement formation 21, the first engagement formation being carried by a cover part 24 which is moveable relative to the remainder of the cover, between a retaining position in which a surface part 29 of the cover part is substantially contiguous with the remainder of the cover surface, and a released position in which the cover part is moved relative to the frame so that the surface part is non-contiguous with the remainder of the cover surface, and the second engagement formation being provided by the cover, the first and second engagement formations being interengageable as an interference fit when the cover is in its closed condition and the cover part is moved to its retaining position. The first engagement formation may comprise a cam surface with a detent and the second engagement formation may comprise a cam follower. The assembly may further comprises a first locking formation on the frame and a second locking formation on the cover which may be lockable together and may preferable be concealed beneath the cover.

Description

Title: Cover and Frame Assembly

Description of Invention

This invention relates to a cover and frame assembly and more particularly to a cover and frame assembly in which the cover may be retained relative to the frame in a closed condition to deter unauthorised opening of the cover.

More particularly but not exclusively the assembly is provided in a ground surface such as a pavement, road or decking, and the cover is movable to an open condition so that access may be gained to services in an access opening, chamber, culvert etc. beneath the assembly, and/or to enable egress of a person through an opening afforded by the frame of the assembly.

It is known to provide a retaining structure to retain the cover in a closed condition. In one example, the retaining structure has included a turnbuckle type locking formation provided on the underside of the cover, which is rotatable through an opening in the cover, using a key. Such a retaining structure is concealed, apart from the opening in a surface of the cover. In another example, a locking device such as a padlock has been proposed to be used, with the padlock engaging a staple which is provided by the frame, which projects through an opening in the cover when the cover is moved to the closed condition.

In the first of these prior proposals, a special key is required to turn the turnbuckle, but the opening in the cover can, where the assembly is provided in a walkway for example, present a trap for the heels of shoes and the like. * 2

In the second of the prior proposals described, the padlock presents an obvious point of attack to a person determined to open the cover. Both the prior proposals therefore have drawbacks.

According to a first aspect of the invention we provide a cover and frame assembly in which the cover has a cover surface and is moveable relative to the frame between a closed condition in which the cover closes an opening afforded by the frame and the cover surface faces outwardly of the frame, and an open condition in which the opening is substantially unobstructed by the cover, the assembly including a retaining structure for retaining the cover in the closed condition, the retaining structure including a first engagement formation, and a second engagement formation, the first engagement formation being carried by a cover part which is moveable relative to the remainder of the cover, between a retaining position in which a surface part of the cover part is substantially contiguous with the remainder of the cover surface, and a released position in which the cover part is moved relative to the frame so that the surface part is non-contiguous with the remainder of the cover surface, and the second engagement formation being provided by the cover, the first and second engagement formations being interengageable as an interference fit when the cover is in its closed condition and the cover part is moved to its retaining position.

Thus the invention provides an assembly in which moving of the cover from the closed condition is resisted by the interference fit between the first and second engagement formations of the retaining structure. However by moving the cover part to the released position, resistance to moving the cover from the closed condition is released so that the cover may be opened.

The present invention enables an assembly to be provided which does not require any specialist tools to engage or disengage the interengaging formations. There need be no opening in the surface of the cover and so heel traps may be avoided. The retaining structure may be concealed by the cover part of the retaining structure and so no obvious attack point is provided to a person determined to open the cover, thus providing a robust deterrent to unauthorised opening of the cover.

The retaining structure does not lock the cover in the closed condition, but the degree of resistance to opening of the cover provided by the interengaged first and second engagement formations, will depend on the force required to be exerted to establish the interference fit, which needs to be overcome to release the interengagement of the first and second engaging formations.

Throughout this specification, by "contiguous" we mean that when the cover part if is in its retaining position, the surface part of the cover part and the surface of the remainder of the cover, are in or are substantially in the same plane.

In one embodiment one of the first and second engagement formations includes a cam surface with a detent, and the other of the engagement formations includes a cam follower which may be moved along the cam surface and into co-operation with the detent when the cover part is moved towards its retaining position with sufficient force.

In one embodiment, the cover part may be hinged to the remainder of the cover, for movement between the retaining and released positions, for example by means of a pivot device, such as an axle for example. Desirably the first engagement formation is provided at or adjacent to the hinge. The cover part may extend from the hinge by a distance to enable sufficient leverage to be exerted between the first and second engagement formations as the cover part is moved to its retaining position to establish the interference * 4 fit, and to enable the interference fit to be released with a suitable prising tool, when it is desired to release the interengagement of the engagement formations, to permit the cover to be opened.

The position of at least one of the first and second engagement formations may be adjustable relative to the other engagement formation, so that the force required to establish the interference fit and to release the interference fit may be adjusted. Desirably the or each engagement formation which is adjustable is adjustable in at least two mutually perpendicular directions, If desired, beneath the cover part, when the cover is in its closed position, the frame may be provided with a first locking formation, and the cover may be provided with a second locking formation which are lockable together by a locking device, such as a padlock, so that even with the retaining structure released, the cover may not be moved to its open position, at least until the locking device is released.

By providing the locking formations beneath the cover part, it will be appreciated that the locking formations are concealed until the cover part is moved to its released position when access may be gained to the locking formations.

In one embodiment the cover may be hinged to the frame for movement between its open and closed conditions, but in another example, the cover may be removable from the frame when moved from its closed condition.

According to a second aspect of the invention we provide a cover and frame assembly in which the cover has a cover surface and is moveable, relative to the frame between a closed condition in which the cover closes an opening afforded by the frame and the cover surface faces outwardly of the frame, and an open condition in which the opening is substantially unobstructed by the cover, the assembly including a cover part which is moveable relative to the remainder of the cover, between one position in which a surface part of the cover part is substantially contiguous with the remainder of the cover surface, and another position in which the cover part is moved relative to the frame so that the surface part is non-contiguous with the remainder of the cover surface, and the frame providing a first locking formation and the cover a second locking formation which are lockable together by a locking device, and wherein the first and second locking formations are provided beneath the cover part and are concealed by the cover part when the cover part is in the one position when the surface part thereof is contiguous with the surface of the remainder of the cover.

Embodiments of the invention will now be described with reference to the accompanying diagrammatic drawings in which: FIGURE 1 is a perspective view of part of an assembly in accordance with the invention showing a cover part in a released position due to prising by a prising tool; FIGURE 2 is a side sectional view through part of the assembly of figure 1 showing a cover part in a retaining position; FIGURE 3 is a view similar to figure 2 but showing the cover part in its released position; FIGUIRE 4 is an alternative cross sectional view of part of the assembly of figure 1 with a cover part in a retaining position, taken on the line 2-2 of figure 2.

Referring to the drawings there is shown a cover and frame assembly 10 which includes a cover 12 and a frame 14, the assembly 10 in use, being located in a ground surface such as a pavement, road or decking, and the * 6 cover 12 is movable to an open condition so that access may be gained to services in an access opening, chamber, culvert etc. 15 beneath the assembly 10, and/or to enable egress of a person through an opening 16 afforded by the frame 14 of the assembly 10.

The cover 12 has an upper cover surface 18 which in this example is provided by a pressed and/or fabricated metal e.g. steel plate, and may be integrally formed with anti-slip formations or outerward provided with an anti-slip finish.

The cover 12 further has a supporting structure of ribs and bars beneath cover surface 18. In another example, the cover 12 could be provided in another material such as aluminium, cast/ductile iron or even a suitable synthetic material as required or a mixture if any of these.

In another example, the cover 12 may be a framework construction with an infill of concrete, blocks or the like, as desired, which concrete or blocks will provide the upper surface 18, and although in the example the cover 12 is shown as a single piece construction, in another example, the cover 12 may be provided by a plurality of cover pieces, preferably joined or interlocked to provide the cover 12.

The frame 14 of the assembly 10 is provided in this example by four sides 14a, 14b, 14c, 14d which may be e.g. formed by pressing in metal such as steel, but the frame 14 may have three or more than four sides or may even be round or part round, and may be a rolled or cast rather than being a fabricated structure, in metal or a suitable synthetic material. Each side may have an "L" or generally a channel section, and the sides 14a, 14b, 14c, 14d may be connected to form the frame 14, by welding and/or fasteners and/or otherwise as required. * 7

The cover 12 is receivable by the frame 14 in a closed condition in which the cover 12 closes the frame opening 16 and the cover surface 18 faces outwardly of the frame 14. Thus the cover 12 is of a configuration corresponding to that of the frame 14. The cover 12 will thus overlie substantially the entire frame 14.

The cover 12 is movable relative to the frame 14 from the closed condition to an open condition in which the opening 16 is substantially unobstructed by the cover 12.

In the example, the cover 12 is hinged to the frame 14 for movement relative to the frame 14 about a pivot axis A. This may be achieved by there being an axle or a pair of stub axles. tn another example though, the cover 12 need not be hinged to the frame 14 but may be connected by an alternative pivot structure which allows the cover 12 movement described. In yet another embodiment, the cover 12 need not be connected to the frame 14 at all, but may be movable from the closed condition to the open position by removing the cover 12 from the frame 14 e.g. by lifting or sliding out.

The assembly 10 includes a retaining structure 25 for retaining the cover 12 in the closed condition, the retaining structure 25 including a first engagement formation 20, and a second engagement formation 21. The first engagement formation 20 is carried by a cover part 24 which is moveable relative to the remainder of the cover 12, between a retaining position as seen in figure 2, in which a surface part 29 of the cover part 24 is substantially contiguous with the remainder of the cover surface 18 i.e. lies in a substantially common plane, and a released position seen in figure 3 in which the cover part 24 is moved relative to the remainder of the cover 12 so that the surface part 29 is non-contiguous with the remainder of the cover surface 18.

The cover part 24 is provided at or towards an edge of the cover 12 so as to overlie the frame 14 beneath.

The second engagement formation 21 is provided by the frame 14 beneath the cover part 24, the first and second engagement formations 20, 21 being interengageable as an interference fit when the cover 12 is in its closed condition and the cover part 24 is moved to its retaining position.

The cover part 24 is movable relative to the remainder of the cover 12 between its retaining and released positions about a hinge axis B, the hinge being provided by a hinge pin 26 which extends between two bars 19a, 19b of the cover support structure 19 and a pair of ribs (one of which is seen at 27 in figure 1) beneath the surface part 29 of the cover part 24. The first engagement formation 20 also extends between the ribs 27 (see figure 4) and is in this example in the form of a bar.

The second engagement formation 21 is in the form of a cam 22 which includes a slight detent 23. The second engagement formation 21 is secured relative to the frame side indicated at 14b. The position of the second engagement formation 21 is adjustable both side-to-side and up and down i.e. in two generally mutually perpendicular directions by means of adjustment fasteners 21a, 21b, so that the cam 22 and first engagement formation 20 can be relatively positioned to provide an interference fit when the cover part 24 is moved from the released position shown in figure 3 to the retaining position shown in figure 2.

The cam 22 of the second engagement formation 21 is shaped so that a considerable downwards force about the pivot axis B of the cover part 24, needs to be imposed on the surface 29 of the cover part 24 to interengage the first engagement formation 20 in the detent 23 of the cam 22. For example, a sufficient force may be established by a person stamping on the cover part 24.

Thus with the cover 12 of the assembly 10 in its closed condition, when the first and second engagement formations 20, 21 are thus interengaged, a considerable force will be needed to disengage the formations 20, 21 subsequently to permit the cover 12 to be moved to its open condition.

Desirably a pair of such retaining structures 25 are provided at two separated positions around the frame 14, for example on two opposite sides of the frame.

More than two retaining formations 25 may be provided as required.

In figure 1, the method of disengaging the first and second engagement formations 20, 21 is illustrated.

It will be appreciated that when the cover part 24 is in its retaining position (figure 2) the surface part 29 of the cover 12 will lie substantially contiguously with the surface 18 of the remainder of the cover 12. A small slot 31 is provided between the cover part 24 and the remainder of the cover 12 this slot 31 being just sufficient to receive a prising tool 33 such as a screw driver -i.e. not a specialist tool, by means of which the cover part 24 may be prised upwards to disengage the first and second engagement formations 20, 21. By virtue of the slot 31 being spaced from the hinge axis B of the cover part 24, maximum leverage may be applied to prise the cover part 24 to its released position.

The cover part 24 includes a bar 40 adjacent the slot 31 against which the prising tool 33 may be brought to bear to protect a lip of the cover part 24 by the slot 31, from distortion. * 10

The retaining structure 25 will provide a considerable deterrent to unauthorised opening of the cover 12. The retaining structure 25 is hidden from view and a prising tool of the right size and strength is required to release the retaining structure(s) 25. However where extra security is required, the frame 14 may be provided with a first locking formation 35 and the cover 12 with a second locking formation 37 indicated in figures 2 and 3.

Each locking formation 35, 37 has a through opening 35a, 37a through which part of a locking device such as a padlock staple may be passed. Thus only an authorised person with the appropriate padlock key can release the locking device to enable the cover 12 of the assembly to be moved to its open condition.

The first and second locking formations 35, 37 are located beneath the cover part 24 some distance from the cover part hinge axis B, and when the cover part 24 is in its retaining position, the padlock or other locking device will be concealed.

Various modifications are possible without departing from the scope of the invention.

In another example the first engagement formation 20 provided by the cover part may be a cam with a detent and the second engagement formation 21 provided by the frame 14, may be a cam follower such as a bar. In each case though, no detent is essential but, when the cover part 24 is moved to its retaining position, considerable force preferably is needed to be exerted to establish the interference fit between the first and second engagement formations 20, 21, and a considerable prising force will be required subsequently to move the cover part 24 to its released position where the first and second engagement formations 20, 21 will be disengaged.

In another example, the cover part 24 need not be hinged to the remainder of the cover 12 but may otherwise be mounted to, or may be separable from the remainder of the cover 12, to permit the cover part 24 to be moved between its retaining and released positions.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof. * 12