This present invention relates to a drain cover and methods for using and removing a drain cover, a drain cover carrier, a set of drain cover carriers and a method for moving a drain cover.

BACKGROUND OF THE INVENTION Drain covers are commonly used to form a lid over the opening of a drain, manhole or other underground access point to prevent people, vehicles or other objects from falling in. They are often removable to allow access for maintenance or other such purposes. Examples of drain covers include manhole covers. Manhole covers are typically manufactured from cast iron of sufficient thickness to be strong enough to withstand heavy loads being placed on them or passing over them. Commonly, manhole covers feature holes or other means into which a hook or other tool may be inserted to lift the cover when access is required.

Another example of a drain cover is a recessed drain cover. Typically, this comprises a tray, into which bricks, paving, concrete or other ground surface or building material may be placed. The tray may then sit on a base portion of a frame positioned around the periphery of the drain such that the surface of the material inside the tray is level with the surrounding ground material. The ability to accommodate material in the tray means that the presence of the drain cover may be hidden to some extent, allowing conformity with the surrounding ground material.

It is often desirable for recessed drain covers to be strong enough to withstand heavy objects, such as vehicles, moving over them. If the tray is not strong enough, it may distort under the overlying weight, damaging the tray or the ground surface material in the tray. The trays are typically manufactured from steel sheet of sufficient thickness to withstand loads in use. In addition, the floor of a tray is often pressed or moulded from steel sheet to include corrugations or ridges to add strength to the structure. A consequence of making the tray strong means that it is also heavy, particularly when filled with ground surface material it is difficult for the user to install, remove and replace the drain cover.

In conventional recessed drain covers, a sand or concrete bedding is often placed in the tray with ground surface material being placed on top of the bedding. This mirrors the laying of the ground surface material on the ground surrounding the drain cover, which may be paviors or paving slabs laid on compacted sand or on concrete.

To ensure that the ground surface material is level within the tray, the installer must take time to ensure that the bedding is of the correct depth within the tray and that the bedding is also flat.

Conventional recessed drain covers may be lifted using tools, such as hooks, which are insertable into corresponding holes formed in the drain cover. However, it is also known that recessed drain covers may have handles built into them. Such handles are often manufactured from plastic and may be retractable into a housing in the drain cover. For example, when the drain cover is in position, the handles may be retracted so they do not protrude above ground level. When lifting of the drain cover is required, the handles may slide out of their housings. However, a drain cover (installed outdoors) is typically exposed to the weather and to dirt and sand which may collect on the ground in the area of the drain cover. In addition, it may be exposed to vehicles and pedestrians passing over it. A drain cover is often exposed to a harsh environment. Consequently, after a period of time, dirt and other material may collect in the housings and prevent the handles from fully retracting or sliding out for use. Furthermore, if the handles are manufactured from plastic, they have a tendency to break, especially in colder temperatures.

The lifting of drain covers may also be made more difficult if the frame surrounding the drain, into which the tray is inserted, becomes distorted. This is a common occurrence, particularly but not exclusively when the frame is manufactured from plastic. For example, the ground surface material surrounding the drain may be compacted and compressed by passing traffic, particularly vehicular traffic. The ground surface material may then press against the frame and distort it, forcing it against the drain cover which has been placed within it. This can result in the cover being even more difficult to remove. The difficulty of removing the drain cover may reach such an extent that the only solution is to dig up the paving or other ground surface material from the tray and possibly also in the vicinity of the drain in order to gain access to the drain, and then to reinstall the ground surface material and a new frame and drain cover.

When access to a drain is required, conventional practice is to lift one side of the drain cover and then to drag the drain cover away from the drain. However, the act of dragging the drain cover may cause damage to the ground surface surrounding the drain. This may be acceptable where a drain is surrounded by a robust surface material, such as tarmac, but is of particular concern for drain covers in places such as indoor shopping centres, where flooring around a drain is often more delicate and intended to be more aesthetic. Damage caused by drain cover removal may be unsightly and potentially dangerous. In addition, the act of dragging a heavy drain cover may be particularly strenuous for the user, potentially leading to injury.

Consequently, there is a desire to provide a drain cover which is easier to manufacture, transport and install, and to remove from over a drain. There is also a desire to provide a more convenient way of moving drain covers towards and away from drains.

SUMMARY OF INVENTION

The invention relates to a recessed drain cover, a platform for use in a recessed drain cover, a tray for use in a recessed drain cover, a tool for lifting a recessed drain cover, a method for accommodating ground surface material within a tray of a recessed drain cover, a removable drain cover, a tool for lifting a drain cover, a method for removing a drain cover, a drain cover carrier, a set of drain cover carriers and a method for moving a drain cover, as defined in the appended independent claims to which reference should now be made. Advantageous or preferred features are set forth in dependent claims. A recessed drain cover according to the present invention, for covering a surface opening of an underground drain, may advantageously comprise: a removable tray for accommodating ground surface material, positionable over the opening; and a platform or scaffold mountable within the tray. In use, the platform may be positioned beneath the ground surface material in the tray. The surface opening may be, for example, a drain or a manhole or any other opening to which access may be required, such as underground electrical or gas maintenance access. The platform may be prefabricated in a size corresponding to a tray of predetermined size, or may be cut to size on installation of the drain cover. Preferably, the platform is mountable and removable as a single unit, and may substantially maintain its structure independently of the tray. The platform may be mountable in and removable from the tray when the tray is positioned over the drain.

The ground surface material may comprise, by way of non-limiting example, paviors, slabs, tiles, gravel, tarmacadam, concrete and/or cement-based aggregate mixed materials. The ground surface material in the tray may comprise more than one layer, for example comprising an upper surface material such as paviors, slabs, tiles, gravel, tarmacadam, concrete and/or cement-based aggregate mixed materials, mounted on a substrate such as concrete, cement or sand.

Preferably, the platform is sufficiently rigid to support the weight of the ground surface material and other loads applied to the drain cover during use, such as the weight of pedestrians or vehicles. This may ensure that the drain cover does not deform or bow under the weight, and consequently, may also ensure that damage to ground surface material accommodated in the tray is reduced or eliminated. The tray, without the platform in place, need not be sufficiently rigid to support the weight of the ground surface material and other loads applied to the drain cover during use, such as the weight of pedestrians or vehicles. A possible consequence of this may be that the tray can be manufactured with a reduced requirement for supporting loads. This could mean that the tray is lighter, may be made of thinner metal sheet and does not need to contain reinforcing features such as corrugations or ridges. The tray may therefore be easier and cheaper to manufacture.

The platform advantageously bridges the surface opening. Thus, the platform may be arranged such that it spans across the surface opening and is supported at either side, for example opposing sides, of the surface opening. To achieve this, edges of the platform may be positioned, in use, such that they sit above a fixed surface at the periphery of the surface opening. The recessed drain cover may be positionable within a frame which is securable around the periphery of the opening of the drain. The frame is preferably manufactured from metal. The frame may comprise side walls extending upwardly from a horizontal base, such that the tray is positionable on the base and within the space defined between the side walls. The recessed drain may be arranged such that when the drain cover is positioned within the frame, an edge of the platform overlies the base of the frame.

The tray may comprise a floor, with the platform being more rigid than the floor. The tray may comprise side walls extending upwardly from the edges of the floor, with the platform resting on the floor. Preferably the platform simply rests on the floor without the need for clamping or other forms of fastening. This arrangement may allow for easy installation and removal of the platform and allow it to be installed and removed independently from the tray. Alternatively or additionally, a cavity may be defined between the platform and the floor, which may allow more efficient draining of water through the tray (where the tray is formed with one or more drain holes). The tray may comprise a reinforced shelf portion adjacent to an edge of the floor, on which the platform is mountable. The floor may be continuous such that it extends substantially across the drain opening or it may not be continuous by for example, forming a lip or sill on which the edges of the platform rest. Preferably the floor is continuous such that ground surface material is substantially prevented from falling through the tray and into the drain.

In a preferred embodiment, the platform could be perforated. If the perforations are through the thickness of the platform, this may allow drainage of water or other fluids through the platform. Alternatively or additionally, the platform may comprise a lattice structure. A lattice structure could allow for a reduction in weight of the platform and also allow for more efficient drainage of fluids. A bedding material such as sand or cement or concrete may be positioned on top of the platform to provide a base for laying a surface material such as paviors or tiles. The upper surface of the platform, and any perforations through the platform, may be designed to receive such a base layer of sand or cement or concrete, for example allowing the cement to key into and bond to the surface of the platform. The platform may define substantially square or rectangular perforations, which preferably have a side length of 20-50 millimetres (mm). The recessed drain cover may also comprise a fluid-permeable membrane overlying the platform. This may help to protect the surface of the platform whilst allowing fluid- drainage. In addition, a fluid-permeable membrane may allow material such as sand or cement or concrete to rest on top of the platform especially if the platform contains perforations or is a lattice structure.

If the floor of the tray is non-continuous, then the drain cover may advantageously comprise a fluid permeable membrane which overlies the platform, or the platform may not be perforated such that ground surface material is prevented from falling down into the drain.

The upper surface of the platform, on which the ground surface material may rest, is preferably substantially planar. Consequently, there is likely to be no need for the installer of the drain cover to ensure that the platform is level such that any ground surface material placed in the tray is also level. This is likely to reduce the time taken to install the recessed drain cover.

A platform which is mountable within the tray may significantly reduce the time taken to install the recessed drain cover. There may be no requirement to construct a bedding of, for example, sand or concrete on which surface material is to be placed. In a conventional recessed drain cover, the construction of the bedding and ensuring that it is the correct depth and is level, can take a significant amount of time.

The platform may comprise any suitable material but may advantageously comprise a fibre-reinforced material, such as fibreglass. Such a material could give high levels of strength and rigidity and with reduced weight compared to, for example, equivalently rigid platforms manufactured from metal. The thickness of the platform could preferably be between 5mm and 50mm, 10mm and 30mm, or 15mm and 20mm. In a preferred embodiment, the lateral dimension of the cover may be between 30 centimetres (cm) and 150cm, depending on its intended use.

The thickness of a platform may be selected in view of parameters such as the lateral dimensions of the cover (and the size of the drain opening), the expected maximum load to be carried by the cover, the rigidity of the material of the platform and the amount of deformation, or flexing, of the platform that is acceptable under load. For example, a platform for use in a drain cover for use indoors in a domestic environment to cover a small (say 30cm) drain opening, for example in a tiled floor, could be relatively thin as the bending moments applied as people walk over the cover would be small. By contrast, a platform for use outdoors in an industrial environment to cover a large (say 1.5 metre (m)) drain opening, would need to be thicker to withstand the bending moment applied by a vehicle, such as a lorry, driving over the cover.

The thickness of the platform may also be selected depending on the space available in the tray, bearing in mind the depth of the tray and the depth required above the platform for installing the ground surface material.

Preferably, the tray is manufactured from metal. Most preferably, the tray is manufactured from steel. Preferably the side walls of the tray flare, or taper, outwardly towards their upper edges away from the base, to prevent the drain cover from jamming in the frame surrounding the drain opening.

In a preferred embodiment of the invention, a drainage hole is defined through the tray. Consequently, water or other fluids may be prevented from accumulating in the tray.

In a preferred embodiment, the recessed drain cover comprises a threaded sleeve or bore secured to the tray for receiving a correspondingly threaded shaft of a tool for lifting the drain cover. The threaded bore is positioned above a jacking opening, which may be defined in a floor of a tray, such that, in use, rotation of the tool causes an end of the threaded shaft to pass through the jacking opening and to abut a fixed surface beneath the floor. Further rotation of the tool may then lift the tray away from the fixed surface. Such a jacking system could provide an easy method for lifting the drain cover. This is particularly advantageous if the drain cover is heavy and/or the drain cover has become jammed over the surface opening. Jacking may help to break a seal which has formed around the edges of the drain cover (for example due to accumulation of dirt, or due to corrosion, or due to deformation of the frame in which the drain cover is mounted, caused by compaction of the ground around the frame) which was hindering the lifting of the drain cover. Preferably, the threaded bore is not obstructed by the ground surface material, such that the threaded bore is accessible to the tool even when the ground surface material has been positioned in the tray. Advantageously, a lifting-point cover may be insertable into the threaded bore such that when the tool is not inserted into the bore, dirt and other material may not accumulate in the bore, which could prevent future insertion of the tool into the bore. The lifting point cover may be a screw-in cap to secure it in place over the bore. An upper portion of the lifting point cover may cover the ground surface material around the lifting point such that, for example, any unsightly cutting of the ground surface material in this area is hidden. Alternatively or additionally the lifting point cover, in use, may be positionable below the edge of the tray to a top surface level no higher than the immediately adjacent filling materials or ground surface material, such that it is flush with the surrounding ground surface material. The lifting point cover may be round and may be compatible with a screwdriver head and/or may be square or hexagonal, so that a spanner or socket set may be used for removal. The cover may have a central socket compatible with an alien key.

The tool used for lifting the recessed drain cover may further comprise a handle which is substantially perpendicular to the axis of rotation of the shaft. This could allow greater torque to be applied when rotating the tool in the corresponding threaded bore. Furthermore, a handle which is substantially horizontal in use could make it easier for the user to lift the drain cover once the threaded shaft of the tool is secured in the bore (the bore typically being vertically oriented in use).

Where a drain cover is positionable within a frame which is securable around the periphery of the opening of the drain, such that the fixed surface beneath the floor of the tray is a portion of the frame, the frame may provide a robust surface for contact with the end of the threaded shaft of the tool. The tool may then be used to lift the drain cover away from the frame, with the end of the tool braced against the frame, thus minimising any risk of dislodging the frame from the drain. The frame may advantageously comprise features as described above, for example, the frame may comprise a base which is substantially horizontal in use and the drain cover may be positionable over the surface opening by supporting it on the base of the frame. The portion of the frame forming the fixed surface against which the threaded shaft of the jacking tool abuts may be the base of the frame. Platforms as described above could be used in existing recessed drain covers. A platform may be cut to size for an existing drain cover tray, or prefabricated for a tray of predetermined dimensions, and installed in a conventional tray as described above.

In addition, drain covers embodying the invention may be used for existing drain openings comprising frames for receiving conventional drain covers. Such drain covers embodying the invention may be sized to be compatible with existing frames.

A method for accommodating ground surface material within a tray of a recessed drain cover, according to a further aspect of the invention, may comprise: mounting a platform in the tray, the platform being more rigid than a floor of the tray; and placing the ground surface material into the tray, covering the platform. The ground surface material used in the method could comprise an upper surface material, such as paviors, slabs or tiles, mounted on a substrate, such as cement, concrete or sand. The platform may be mounted on the floor of the tray, or may be mounted on a shelf portion of an interior wall of the tray. A removable drain cover according to a further aspect of the invention may comprise a threaded bore for receiving a correspondingly threaded shaft of a tool, in which the threaded bore is positioned above a jacking opening defined in the drain cover such that, in use, rotation of the tool causes an end of the threaded shaft to pass through the jacking opening and to abut a fixed surface beneath the drain cover. Further rotation of the tool may lift the drain cover away from the fixed surface. The removable drain cover may be a recessed drain cover, a manhole cover or any other type of cover for a surface opening to which access may be required.

The drain cover may further comprise a lifting-point cover which is insertable into the threaded bore, such that when the tool is not inserted into the bore, dirt and other material may not accumulate in the bore, which could prevent insertion of the tool into the bore. The lifting point cover may be a screw-in cap to secure it in place over the bore. The removable drain cover may also be positionable within a frame which is securable around the periphery of the opening of the drain, such that the fixed surface beneath the floor of the tray is a portion of the frame. In this arrangement the tray could be lifted relative to the frame and the frame may provide a robust surface for contact with the threaded bore of the tool. The frame may also comprise a base which is substantially horizontal in use and the drain cover may be positionable over the surface opening by supporting it on the base of the frame. The portion of the frame forming the fixed surface against which the threaded shaft of the jacking tool abuts may be the base of the frame.

Preferably, the removable drain cover comprises a tray for accommodating a ground surface material, the tray having a floor in which the jacking opening is defined. Even more preferably, the threaded bore is not obstructed by the ground surface material.

The removable drain cover may also comprise a prefabricated platform as described above.

The tool used for lifting the removable drain cover may further comprise a handle which is substantially perpendicular to the axis of rotation of the shaft.

A method for removing a drain cover, according to a further aspect of the invention, may comprise: inserting a threaded shaft of a tool into a corresponding threaded bore of the drain cover, the threaded bore being positioned above a jacking opening defined in the drain cover; and rotating the tool such that an end of the threaded shaft passes through a jacking opening, to abut a fixed surface beneath the drain cover, such that the drain cover is lifted away from the surface. Preferably, the fixed surface is a portion of a frame secured around the periphery of the drain for receiving the drain cover, such that rotating the tool lifts the drain cover from the frame.

A drain cover carrier according to a further aspect of the present invention may advantageously comprise: a means for releasably securing the carrier to a drain cover; and a rolling member such as a wheel connected to but spaced from the means for securing the carrier to the drain cover, such that when the carrier is secured to the drain cover, and the drain cover is positioned over a drain, the wheel contacts a surface alongside the drain. Consequently, once the carrier is secured to the drain cover, the cover may simply be rolled away from a drain. Similarly, when the drain cover is to be replaced, it may be rolled into position directly over a drain before being lowered into position. The term "drain" as used herein, in relation to drain cover carriers, encompasses any surface opening to which access may be required. For example, this may include a manhole, or underground electrical or gas maintenance access points.

The means for releasably securing the carrier to the drain cover is preferably a clamp. Alternatively, or in addition, the means for releasably securing the carrier to the drain may comprise a hook, a platform on which the drain cover can sit or may even comprise a magnet.

In a preferred embodiment, a clamp is provided which comprises a first arm positionable over an upper side of the drain cover and a second arm for contacting or supporting a lower side of the drain cover. Consequently, the clamp may be positioned such that a portion or edge of the drain cover is located between the two arms.

The clamp may be releasably securable to a drain cover in any convenient way, for example using a clamp tightening element. For example, the clamp may comprise an over-centre clamping mechanism, a sliding clamping mechanism, a ratchet mechanism or a mechanism using a screw thread. With the latter arrangement, the clamp may comprise a threaded bore defined through the first arm for receiving a correspondingly threaded shaft of a tightening element, such that in use, rotation of the tightening element causes the shaft (or other portion of the clamp urged by the tightening element) to abut the drain cover, sandwiching the drain cover between the tightening element and the opposing, second arm. The adjustable tightening element may allow different sizes and thicknesses of drain cover to be accommodated in the clamp.

Preferably, a protective spacer is positionable between the tightening element and the drain cover. This may be in the form of a washer or a disc of rubber material which helps to absorb or dissipate the pressure exerted by the tightening element. The spacer may be permanently attached to the tightening element, and/or may be rotatably attached to the end of the tightening element. If the clamp comprises first and second arms as described above, it is also advantageous for the first arm to be joined to or spaced from the second arm by a cross-support or brace which is substantially perpendicular to the first and second arms. This may result in a U-shaped arrangement between the two arms and the cross-support. The arms may be arranged differently in relation to the cross-support depending on the shape of the drain cover but most commercially available drain covers have substantially flat upper and lower surfaces, in which case the first and second arms may conveniently be parallel to each other. Preferably, the first arm is spaced from the second arm by a distance of 10 to 200mm, 50 to 150mm, 75 to 120mm or 90 to 110mm; such that the thicknesses of most commercially-available drain covers may be accommodated within the clamp. The first and second arms may be the same or different lengths, and the lengths of each arm may vary depending on, for example, the dimensions and weight of the drain cover, or range of drain covers, with which a carrier is intended to be used. Advantageously, a carrier may be designed to accommodate a range of different sizes and weights of drain cover, but more than one size of carrier may be needed to accommodate all sizes and types of drain cover. In a preferred embodiment, the length of the first and/or second arm is 50 to 100mm, 60 to 90mm or 65 to 75mm.

In a preferred embodiment, a carrier is arranged such that when it is secured to a drain cover, the rolling member, or wheel, is spaced from an edge of the drain cover by a distance of 50 to 100mm, 60 to 90mm or 70 to 80mm. If the carrier has a cross- support as described above, the rolling member is preferably mounted on a mounting arm which extends from the cross support. The mounting arm may extend in a direction which is substantially opposite to the direction in which the first and second arms extend from the cross-support.

The rolling member is preferably a wheel although it may comprise a ball, mounted for rotation in any direction. If a wheel is used, preferably the wheel is mounted as a jockey wheel or castor capable of travelling in any direction to allow greater manoeuvrability. The wheel may comprise a releasable brake to prevent rotation of the wheel, for example, if the drain cover is being moved on a slope. Preferably, the carrier comprises a single wheel.

Advantageously the rolling member and clamp may be arranged such that in use, a lowest portion or bottom of the clamp is higher than a lowest part or bottom of the rolling member. Consequently, if the drain cover is being supported on the carrier, and the rolling member of the carrier is on the ground or other surface alongside the drain, the lowest portion of the clamp may clear the edge of the drain and may not drag or scrape on the surface alongside the drain. Preferably, the lowest portion of the clamp, in use, is maintained at a height greater than 1 , 2, 5, 10, 20 or 50mm above the lowest part of the rolling member.

A set of drain cover carriers according to a further aspect of the present invention may advantageously comprise three or more carriers as described above, which are releasably securable to a drain cover so that the drain cover is rollably supported on the rolling members of the carriers. A set of drain carriers secured to a drain cover may allow greater stability and they may be securable to the drain cover independently of each other providing flexibility with respect to, for example, different shapes and sizes of drain covers. For example, heavier drain covers may require a greater number of rolling members to move the drain cover and a substantially rectangular drain cover may be sufficiently stabilised by a set of four drain cover carriers secured to opposite sides of the drain cover, arranged in pairs.

In a further aspect of the invention, a drain cover may comprise a threaded bore defined within the drain cover for receiving a correspondingly threaded shaft of a lifting tool, or jacking tool, such that, in use, rotation of the tool causes an end of the threaded shaft to abut a fixed surface (such as a portion of a rim of the drain) beneath the drain cover. Further rotation of the tool then lifts the drain cover away from the fixed surface, and therefore from the drain, sufficiently to secure one or more carriers, as described above, to the drain cover. Thus, this jacking system may provide a means for lifting the drain cover, making it easier to position the clamp or other means for securing the carrier, to the drain cover. Using this lifting mechanism, the user may not be required manually to lift the drain cover at any point during removal or replacement.

The lifting tool may need to be partially withdrawn, or unscrewed, after the drain cover has been lifted and a set of carriers attached, in order to allow the drain cover to be rolled away from the drain. The lifting tool may then, however, be used as a brake, by rotating the lifting tool until it extends downwardly from the drain cover sufficiently to contact the ground. The lifting tool may also be used as a handle for guiding the drain cover during rolling. In a further aspect of the invention, one or more carriers (for example two carriers) may be secured at or near one end, or one corner, of a drain cover. The carrier or carriers may then support the weight of the drain cover and allow the drain cover to be pivoted or rolled about a pivot point near an opposite end or corner of the drain cover, so as to rotate the drain cover away from the drain. Such an arrangement may advantageously allow moving of the drain cover using fewer carriers then would otherwise be needed.

This aspect of the invention may be particularly advantageous where a drain cover comprises a threaded bore for receiving a lifting tool, as described above. The lifting tool, contacting a fixed surface of a rim of the drain beneath the drain cover, may then advantageously be used as a pivot. It would be advantageous for the fixed surface to which the tool abuts to have a means for preventing slippage of the tool during pivoting. This may, for example, be a dimple or welded-on washer.

In a preferred embodiment of this arrangement, a drain cover may comprise two threaded bores for receiving lifting tools at opposite sides, ends or corners of the drain cover. The two lifting tools may then be used to lift the drain cover, and one or more carriers secured to the drain cover near one of the lifting tools. That lifting tool may then be unscrewed, or retracted, until the wheels of the carriers are in contact with the ground and the end of the lifting tool is clear of the rim of the drain. The other lifting tool may remain extended so as to act as the pivot.

A method for moving a drain cover according to a further aspect of the invention may comprise: lifting the drain cover; releasably securing a drain cover carrier, as described above, to the drain cover; and rolling the drain cover using the rolling member, or wheel, of the drain cover carrier.

Preferably, lifting the drain cover involves rotating a threaded shaft of a lifting tool in a correspondingly threaded bore defined within the drain cover such that an end of the threaded shaft abuts a fixed surface beneath the drain cover.

The drain cover carrier may comprise a clamp, and releasably securing the drain-cover carrier to the drain cover may involve clamping the drain-cover carrier to the drain cover using the clamp. In a preferred embodiment this may be achieved by rotating a threaded shaft of a tightening element within a correspondingly threaded bore defined through a first arm positioned adjacent to the upper side of the drain cover, such that the tightening element abuts the drain cover, clamping the drain cover between first and second arms of the carrier. The method may also comprise preventing rolling by applying a releasable brake to the rolling member or by rotating a threaded shaft of a tool in a correspondingly threaded bore defined within the drain cover, such that an end of the threaded shaft contacts a surface on which the drain cover is being rolled. The tool may dig into the ground or even lift the rolling member off the ground.

In a preferred aspect, a method according to the invention may be carried out by a single user. Thus, a drain cover may be lifted and moved, without risk of injury, by a single user. This is particularly advantageous for large or heavy drain covers.

SPECIFIC DESCRIPTION OF THE PREFERRED EMBODIMENT

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 recessed drain cover according to an embodiment of the invention, mounted in a frame.

Figure 2 is a vertical section, on A-A, of the recessed drain cover shown in Figure 1.

Figure 3 is a three-quarter view of a tray from the recessed drain cover as shown in Figures 1 and 2.

Figure 4 is a three-quarter view of a prefabricated platform from the recessed drain cover as shown in Figures 1 and 2.

Figure 5 is a three-quarter view of the frame as shown in Figures 1 and 2.

Figure 6 is a sectional side view of a recessed drain cover according to an embodiment of the invention. Figure 7 is a sectional side view of a recessed drain cover according to another embodiment of the invention.

Figure 8 is a sectional side view of a recessed drain cover according to yet another embodiment of the invention.

Figure 9 is a view of the top of a removable drain cover according to an embodiment of the invention, mounted in a frame. Figure 10 is a section, on B-B of the recessed drain cover shown in Figure 9. Figure 11 is a side view of a jacking tool.

Figure 12a is a side view of a drain cover carrier according to an embodiment of the invention.

Figure 12b is an oblique view of a drain cover carrier similar to that shown in Figure 1a. Figure 13 is an isometric view of a recessed drain cover to which four drain cover carriers, as shown in Figure 1a, have been attached.

Figure 14 is a side view of the recessed drain cover shown in Figure 2, positioned over a drain during raising or lowering of the drain cover.

Figure 15 is an isometric view of a drain cover to which two drain cover carriers have been secured, according to an embodiment of the invention.

Figure 16 is a top view of a drain cover to which two drain cover carriers have been secured, according to another embodiment of the invention.

Figure 17 is a three-dimensional view of a drain cover carrier according to a further embodiment of the invention. A recessed drain cover 1 as shown in Figures 1 to 5, has a removable steel tray 2 for accommodating ground surface material 5, which is positionable over a surface opening 3 of an underground drain. The tray comprises a floor 4 and side walls 6 extending upwardly from the edges of the floor. The floor of the tray has a drainage hole 18 or passage defined through it. Water which collects in the tray can then pass through the drainage hole into the drain beneath.

A sleeve comprising a vertical threaded bore 10 is welded to a side wall of the tray above a jacking opening 11 , defined in the floor of the tray. The threaded bore is not obstructed by the ground surface material 5 because it penetrates through or between the material. Consequently, when ground surface material is placed in the tray, the bore opening 13 is visible and accessible to a jacking tool (not shown). The bore opening is coverable by a lifting point cover 12, in the form of a screw-in cap. An enlarged head of the screw-in cap sits over the ground surface material whilst a lower part of the cap screws into the threaded bore. The drain cover also comprises a prefabricated platform 8 which rests on the floor of the tray and is positioned in the tray such that it bridges or spans the surface opening. The platform is manufactured from fibreglass and is more rigid than the floor of the tray. It forms a lattice structure which advantageously makes the platform lighter than if it otherwise would be, without significantly compromising its rigidity. The upper surface of the platform is flat or planar and the lower surface of the platform which contacts the floor of the tray is also flat. At each end of the platform, a section 7 is cut out to fit around the jacking sleeves 10 and to allow the unhindered passage of the jacking tool to the base of the tray and the jacking opening. The recessed drain cover 1 is positionable within a frame 14 which is secured around the periphery of the drain opening 3. The frame is manufactured from metal, specifically steel, and has a base which is horizontal in use such that the drain cover is positioned over the surface opening by supporting it on the base. The frame has side walls 17, which extend upwardly from the horizontal base such that the drain cover is accommodated within the space defined between the side walls of the frame and such that the edges of the platform overlie the base of the frame. Furthermore, the base of the frame forms the fixed surface which the threaded shaft of the tool abuts or contacts. Thus, the tray is positioned within the frame such that the jacking opening 11 of the tray is situated over the base of the frame. The drain cover sits within the frame such that the top of the ground surface material in the tray is level with the surrounding ground material 24. In use, ground surface material is accommodated in the tray 2 of the recessed drain cover by first mounting the prefabricated platform 8 in the tray and placing the ground surface material 5 into the tray such that it is placed on top of the platform and is supported by the platform. The ground surface material may be laid directly on to the platform or it may comprise a bedding or support layer 5a, for example of sand or cement, and a surface layer 5b, for example of paving or tiles. A membrane, such as a water permeable membrane (not shown), may, if required, be positioned between the platform and the ground surface material. The mounting of the platform and/or ground surface material in the tray may take place when the tray is either already positioned within the frame or when the tray is outside of the frame. If the drain cover is not accommodated within the frame, then it may be lifted into the frame by inserting a jacking tool (not shown) into one or both of the threaded bores by winding the tool such that the threaded shaft engages with the threaded bore, and using the handle of the tool to lift the drain cover into position.

The ground surface material is cut or shaped as required to fit around, and not obstruct, the threaded bores. If the drain cover is required to be removed, such as during maintenance, then the threaded shaft of the tool is inserted into a threaded bore and is rotated such that the end of the threaded shaft passes through the jacking opening 11 and contacts the base of the frame 16, underneath the drain cover. As the tool is wound by the user, the drain cover is lifted away from the base of the frame.

Figure 6 shows another embodiment of a recessed drain cover. Features similar to those in Figures 1 to 5 have been given like reference numerals. The drain cover is substantially the same as that shown for the embodiment in Figures 1 to 5, except that the floor 4 of the tray 2 is not continuous and instead forms a sill on which the edges of the platform 8 sit. Advantageously, less material is required to manufacture the tray and so the drain cover is lighter than if the floor was continuous. However, in order to prevent ground surface material falling through the tray and into the drain, the platform used with such a tray should be continuous and not perforated. Figure 7 shows another embodiment of a recessed drain cover. Features similar to those in Figures 1 to 5 have been given like reference numerals. The drain cover is substantially the same as shown for the embodiment in Figures 1 to 5, except that there exists a shelf portion 22 connected to the walls 6 of the tray 2. The shelf portion is adjacent to an edge of the floor 4 but is positioned such that when the platform 8 is mounted on top of the shelf portion, a cavity 20 exists between the floor and the platform.

Figure 8 shows another embodiment of a recessed drain cover. Features similar to those in Figures 1 to 5 have been given like reference numerals. The drain cover is substantially the same as shown for the embodiment in Figures 1 to 5, except that a cavity 20 exists between the floor 4 of the tray and platform 8. The platform at its edges is formed with legs or with a downwardly-extending peripheral flange 9, which sits on the floor of the tray.

Figures 9 and 10 show an embodiment of a removable drain cover 25 in the form of a circular manhole cover. Features similar to those in Figures 1 to 5 have been given like reference numerals. The manhole cover has a threaded bore 10 for receiving a correspondingly threaded shaft of a tool (not shown), in which the threaded bore is positioned above a jacking opening 11 defined in the drain cover. A lifting point cover 12, in the form of a plug is insertable into the top portion of the threaded bore.

The manhole cover is positionable within a fixed circular frame 14, which is secured around the periphery of an opening of a drain 3. The cover sits in the frame, on top of the base of the frame 16, such that the top surface of the cover is level or flush with the surface of the surrounding ground material 24. The base of the frame forms a fixed surface against which the threaded shaft of the tool abuts or contacts. Thus the jacking opening is positioned such that it is above but directly adjacent to the base of the frame.

In use, the manhole cover is removed by inserting the tool into the threaded bore and rotating the tool such that the end of the threaded shaft of the tool passes through the jacking opening and contacts the base of the frame, underneath the manhole cover. As the tool is wound by the user, the drain cover is lifted away from the base of the frame and consequently, is lifted away from the opening of the drain. Figure 11 shows a jacking tool 26 which is suitable for use with the recessed drain cover shown in Figures 1 to 5 or the removable drain cover shown in Figures 9 and 10. The tool has a threaded shaft 28 and a handle 30. The handle is perpendicular to the axis of rotation of the threaded shaft C.

In use, the threaded shaft is inserted into a threaded bore (not shown) and the tool is rotated about axis C such that the end of the threaded shaft passes through a jacking opening (not shown) in the drain cover to abut a fixed surface (not shown) beneath the drain cover. Further rotation of the tool lifts or jacks the drain cover away from the fixed surface. A drain cover carrier 101 as shown in Figures 12a, 12b, 13 and 14 has a means for securing the carrier to a drain cover in the form of a clamp 104. The clamp has a first, upper arm 106 and a second, lower arm 108. The two arms are parallel to each other and are joined by a cross-supporting bridge or brace 118, which is perpendicular to the first and second arms. The length of the arms measured from where they are attached to the bridge is about 70mm and the width of the arms is about 60mm. The arms are spaced from each other by a distance of approximately 100mm.

A tightening element in the form of a bolt 110 with a T-shaped handle and threaded shaft 112 engages with a threaded bore or hole 114 defined within the first arm.

A jockey wheel 120 is attached by a pin 122 to a mounting arm 124 such that it may swivel or rotate freely about the pin. The mounting arm extends from the cross-supporting bridge 118 such that it is perpendicular to the bridge but protrudes in the opposite direction to the first and second arm. The wheel is thus spaced from the bridge and from the first and second arms of the clamp.

In use, the carrier 101 attaches to the edge of the drain cover (as shown in Figures 13 and 14) by placing the upper arm 106 over the upper side of the drain cover and by supporting or resting the lower side of the drain cover on the lower arm 108. The bolt 110 is then tightened such it contacts or abuts the upper surface of the drain cover, sandwiching the drain cover between the bolt and the lower arm. A solid rubber disc 116 attached to the bolt may be placed between the threaded shaft of the bolt and the upper surface of the drain cover to spread the pressure exerted by the threaded shaft and so prevent damage. The wheel 120supports the weight of the drain cover and is Tollable on the surface alongside the drain or any surface on which the drain cover is required to be moved. The bottom arm of the clamp 8 is at a height of about 10 millimetres higher than the bottom of the wheel.

After use, removal of the carrier is achieved by loosening the bolt 110 such that it no longer exerts pressure on the upper side of the drain cover.

The carrier 101 as shown in Figures 12a and 12b is typically used as one of a set of carriers to support and move drain covers. Figure 13 shows an arrangement of four such carriers secured to a recessed drain cover 2. The recessed drain cover has a tray 129 which houses ground material 130. The recessed drain cover has threaded bores 126 which can receive a threaded shaft of a jacking tool (not shown). The bottom of the tray 129 defines holes through which the tool is able to pass and subsequently contact a fixed surface of the drain beneath the drain cover. This provides a mechanism for lifting the drain cover relative to the fixed surface.

The set of carriers is spaced around the edges of the drain cover such that there are two opposing pairs of carriers. The upper arm 106 of the clamp 101 of each carrier is placed over the ground material and the bottom of the tray rests on the lower arm of the clamp. The bolt 110 contacts the ground material such that the drain cover is held securely in place between the bolt and the lower arm of the clamp. The weight of the drain cover is then distributed between the wheels 101 of the carriers.

In use, the drain cover 102 can be rolled in any direction along the ground and the wheels 120 are spaced from the edges of the drain cover by approximately 75 millimetres owing to their positioning on the mounting arms. The spacing of the wheels from the edge is such that that if the drain cover is located directly over a drain (not shown), the wheels will support the drain cover on the surrounding ground to allow movement away from the drain. Rolling of the drain cover can be prevented by turning the jacking tool or tools (shown in Figure 3) such that it/they protrude from the base of the drain cover to such an extent that it/they contact(s) the ground underneath the drain cover.

Figure 14 shows the drain cover of Figure 13 being lifted from a drain 136. A jacking tool 128 is engaged with each threaded bore 126 and protrudes from the base of the tray 131, through an exit hole (not shown). Each tool contacts the base 138 of the frame 132, on which the drain cover rests when covering the drain. The wheels 120 of the carriers are positioned over the surface of the ground 134 alongside the drain, although not contacting the surface. In this position, the weight of the drain cover is being supported by the jacking tools.

Figure 14 therefore shows the arrangement at a point during raising or lowering of the drain cover when the carriers can be secured to the drain cover, or can be removed from the drain cover. For the carriers to be secured to the drain cover, the jacking tools 128 are rotated in the threaded bores lifting the drain cover relative to the base 138 of the frame 132. The drain cover is lifted sufficiently (as shown in Figure 14) so that the carriers 101 can be secured, with the base of the tray 131 resting on the lower arm 8 of each clamp and the upper arm 106 of each clamp being placed over the upper surface of the drain cover. The bolt 110 of each clamp is then tightened as described above. The jacking tools are then rotated to lower the drain cover towards the drain, so that the weight of the tray becomes supported by the wheels 120, resting on top of the ground or floor 134 surrounding the drain 136. The jacking tools can then be removed completely, if desired, or they can be left in place to serve as handles for a user to use when rolling the drain cover, or as brakes as described above by screwing them downwards into contact with the ground or floor. The drain cover can then be wheeled away from the vicinity of the drain.

For the carriers to be removed and the drain cover to be replaced, the drain cover is rolled such that it is positioned directly over the drain 136 and the jacking tools 128 are rotated or screwed downwards until they abut the base 138 of the frame 132 and lift the drain cover, taking the weight off the wheels 120 (as shown in Figure 14). The carriers are then removed by loosening the tightening elements. Once all the carriers have been removed, the jacking tools are rotated, or unscrewed, lowering the drain cover into the frame such that it sits on top of the base 138, covering the drain.

Figure 15 shows a drain cover 102 to which two drain cover carriers have been secured. Similar features to those in Figures 12 to 14 have been given like reference numerals. The drain cover has two threaded bores 126 for retaining jacking tools 128. These are situated at opposite corners of the drain cover. As shown in Figure 15, two jacking or lifting tools have been used to lift the drain cover, and two drain cover carriers 101 have been secured to the drain cover in the vicinity of one of the tools.

The jacking tool has been removed from the threaded bore in the vicinity of the two carriers such that this corner of the drain cover is supported by the carriers. At the opposite corner, it is supported by the remaining jacking tool, which protrudes from the base of the drain cover to abut a fixed surface beneath the drain cover (not shown). The fixed surface has a dimple or depression in which the end of the tool sits to prevent slippage.

The drain cover can then be pivoted about the remaining tool, while the wheels of the carriers roll along the ground, until the drain is uncovered.

Figure 16 shows a similar arrangement to Figure 15, but the threaded bores 126 are arranged at opposite ends, rather than corners, of the drain cover as shown in Figures 13 and 14, and the two carriers 101 are secured to the same edge, rather than different edges of the drain cover 102. However, the pivoting method as described for Figure 15 also applies to the arrangement in Figure 16.

It is important that the wheels 120 are situated far enough away from the drain cover so that when pivoting occurs, they do not roll into the drain. The mounting arms 124 of the carriers are sufficiently long to achieve this, by spacing the wheels sufficiently far from the edge of the drain cover.

Figure 17 shows an adjustable skate which can be adapted to fit a variety of sizes of drain cover. Similar features to those in previous embodiments have been given like reference numerals.

In this embodiment the upper arm 106 and the lower arm 108 are not fixedly connected by a cross-supporting bridge. The cross-supporting bridge is separated into an upper cross-support 118a and a lower cross-support 118b. The upper arm and upper cross-support are movable relative to the lower arm and lower cross- support. The upper cross-support has attached to it a guide tube 154 defining a threaded passageway or bore with which a threaded bar 150 engages. The threaded bar extends downwardly towards the mounting arm 124. The mounting arm defines an aperture 158, through which the threaded bar passes. A fixed bolt or washer (not shown) is connected to the bottom of the bar positioned underneath the mounting arm.

The threaded bar 150 has a wing nut or handle 160 fixed to its upper end for allowing rotation of the threaded bar.

A pair of parallel rods 152 is attached to the upper cross-support 118a. A pair of parallel, tubular rod receivers 156 is fixed to the mounting arm 124, which are able to receive the rods, such that the rods are slidable within the receivers along their longitudinal axis. The cooperating rods and receivers act to maintain alignment of the upper arm 106 and lower arm 108. The carrier is manufactured from 4mm mild steel.

The length of the upper and lower arms 106, 108 measured from where they attach to the upper and lower cross-supports 118a, 118b respectively is about 75mm. The width of the arms, cross-supports and mounting arm 124 is about 50mm. The length of the mounting arm is about 110mm. The length of the upper cross-support is about 30mm and the length of the lower cross-support is about 65mm. The rod receivers 156 have a length of about 100mm of which 30mm protrudes above the mounting arm. There is also approximately a 20mm clearance between the bottom of the castor wheel 129 and the bottom edge of the lower arm 108.

In use, the distance between the upper arm 106 and the lower arm 108 is adjustable such that the carrier 101 may fit a variety of drain cover dimensions. The distance between the arms is adjustable between about 65 to 155mm. This is achieved by turning the wing nut 160 which turns the threaded bar within the threaded passageway of the guide tube 154, enabling the upper arm to move up or down relative to the lower arm. The adjustable clamp, as described in this embodiment, may be applicable to a wide range of embodiments of the invention.