GB2493852A - Device for keeping manhole cover in open position - Google Patents

Abstract

A device 30 for maintaining a manhole cover in an open position, the device having means 20 for engaging with a surface 18, 19 at a perimeter of a manhole opening and means 40 for engaging with the manhole cover 10. There is a means 30 for maintaining a separation between the surface engaging means and cover engaging means. The surface engaging means may be a right angled or L-shaped plate 23, 24 and may be rotatably coupled to the separation means, the cover engaging means may be a clamp 42 which may rotatably coupled to the separation means. The device may also be shaped like a truncated triangle (figure 9a) with parallel clamp plates (903, figure 9a) which engage with the cover, and a base portion (955, figure 9a) which engages with the ground. A second invention in has cover engaging means coupled to a base portion.

Description

Manhole Cover Support Device The present invention relates to a device such as a prop or other support, and more particularly to a prop for maintaining a manhole cover, especially a hinged manhole cover, in an open position with respect to a manhole opening.

Manholes allow access to a system or installation, and are usually provided at an upper opening of the system. Common examples include manholes provided to allow access to sewer systems.

Existing manhole covers are commonly located on roads, and therefore must be able to withstand both people and/or vehicles resting on or passing over them.

Consequently, the covers are often made from thick metal or concrete, and therefore are therefore generally heavy and cumbersome to open.

Hinged manhole covers, such as the exemplary manhole cover illustrated in simplified form in Figures IA to 1C, are widely used. Generally, these include a specially designed hinge that is configured to maintain the manhole cover in an open position with respect to the manhole opening once opened past a certain point. This is intended to allow a worker to enter and exit a manhole safely.

However, manhole covers are often not replaced for several years, or potentially longer, and over time the hinges are known to wear resulting in their failure to secure the cover in an open position safely. There have been several known occasions in which the hinges have been known to fail, resulting in the manhole cover dropping unexpectedly and in some cases injure a worker seriously, for example resulting in the loss of a limb.

The present invention seeks to alleviate this issue by providing a manhole cover supporting device for maintaining a manhole cover in an open position.

According to one aspect of the present invention there is provided a manhole cover support device for maintaining a manhole cover in an open position with respect to a manhole opening, said manhole cover support device comprising: means for engaging with a surface proximate to a perimeter of a manhole opening; means for engaging with the manhole cover in the open position; means for maintaining a separation between the surface engaging means and the cover engaging means such that, in operation, said manhole cover is maintained in said open position.

The manhole cover engaging means may comprise a clamp for clamping to the manhole cover to secure the device to the manhole cover. The manhole cover engaging means may comprise means for supporting the manhole cover in the open position without the need for clamping.

The manhole cover engaging means may be rotatably coupled to said separation maintaining means. The surface engaging means may be rotatably coupled to the separation maintaining means. The surface engaging means may comprise means for adjustably restricting the extent to which the separation maintaining means and the surface engaging means can rotate relative to one another.

The surface engaging means may comprise a portion for engaging a surface extending into the manhole opening at its perimeter and/or may complise a portion for engaging a surface extending away from the manhole at the perimeter of the manhole opening.

The separation maintaining means may comprise a plate, which may be generally triangular in shape.

The surface engaging means may comprise an edge of the plate.

The surface engaging means may comprise a lip extending from said plate (e.g. extending substantially perpendicularly from said plate).

The cover engaging means may be disposed on one face of said plate.

The device may comprise means for displaying signage (e.g. a warning sign), which may be disposed on a face of the piate.

The soparation maintaining moans may comprise an elongate member and may be adjustable in length. Specifically, the separation maintaining means may comprise a first portion and a second portion coupled to the first portion, and configured for movement relative to the first portion, whereby to provide said adjustability in length. Further, the first portion may comprise a first elongate member and the second portion may comprise a second elongate member received by said first elongate member for movement in a longitudinal direction relative to the first elongate member whereby to provide said adjustability in length.

The device may comprise means for limiting the extent to which said second portion can move relative to said first portion to provide said adjustability in length. The limiting means may comprise means for limiting the maximum extent to which said second portion can move relative to said first portion to provide an increased length. The limiting means may comprise means for limiting the maximum extent to which said second portion can move relative to said first portion to provide a shortened length. The means for limiting the maximum extent to which said second portion can move relative to said first portion to provide a shortened length may be adjustable to change the extent to which said second portion can move relative to said first portion to provide a shortened length.

The device may further comprise means for anchoring the device to an anchor point, for example, a cable connected to the device and means for releasably connecting the cable to the anchor point.

The manhole cover may be hingedly connected to a hinged edge of the perimeter of the manhole opening.

The surface engaging means may be configured to engage with a further edge of the perimeter other than the hinged edge. The further edge may be an edge of the perimeter extending from said hinged edge and the further edge may be substantially perpendicular to the hinged edge. The further edge may opposite the hinged edge and it may be substantially parallel to the hinged edge.

The surface engaging means may be configured to engage along a substantial length of the perimeter.

The surface engaging means may be configured to engage along a substantial length of said edge. In particular, the surface engaging means may be configured to engage along more than half of said edge.

The device may further comprise means for bracing the surface engaging means in a position proximate to the perimeter, wherein said bracing means is coupled to the surface engaging means and configured to engage with the manhole cover at a point proximate to the hinged connection, whereby to brace the surface engaging means.

The surface engaging means may comprise a base portion shaped to engage with the surface.

The device may be removably engageable with the manhole cover. The device may also be portable.

According to another aspect of the invention there is provided a device for maintaining a manhole cover in an open position with respect to a manhole opening located in a surface (e.g. a road), said device comprising: a base portion shaped to engage with the surface; and means for securely engaging with the manhole cover in the open position, said cover engaging means being coupled to said base portion and configured to be maintained in a fixed position relative to said base portion, whereby to maintain a manhole cover in an open position with respect to a manhole opening.

According to another aspect of the invention there is provided a method comprising using a device of any aspect herein disclosed to maintain a manhole cover in an open position. A kit comprising parts to assemble a device of any aspect herein disclosed.

Embodiments of the invention will now be described by way of example only with reference to the attached figures in which: Figures IA, lB and 1C show, in simplified form, an exemplary system in which the present invention can be utilised; Figures 2 and 3 show, in simplified form, a manhole cover supporting device; Figure 4 shows manhole cover supporting device in use supporting a manhole cover; Figure 5 shows variation of the of the manhole cover supporting device; Figures 6A and 6B show another variation of the manhole cover supporting device; Figure 7 shows show another variation of the manhole cover supporting device; and.

Figure 8 shows another variation of the manhole cover supporting device; Figure 9a illustrates a view of a manhole cover supporting device according to another embodiment, from a rear view; Figure 9b illustrates the device of Figure 9a from top view; Figure 9c illustrates the device of Figure 9a from side view; Figure 10 illustrates the device of Figure 9a from front view; Figure 11 illustrates the device of Figure 9a attached to a manhole cover; Figure 12 shows another variation of the manhole cover supporting device.

Figures IA, lB and 1C show, in simplified form, an exemplary system in which the present invention can be utilised, comprising a manhole opening 5, a manhole frame 14 and a manhole cover 10. When installed, the manhole frame 14 defines the internal perimeter of the manhole opening 5 and is generally reGtangular. A lip 16 is provided against whiGh the cover 10 may be received when the cover is in a closed position. The lip 16 may be an integral part of the frame 14 or may be formed by the manhole opening 5 into which the frame 14 and cover 10 are installed.

The cover 10 is generally rectangular and is hingedly connected to the frame 14 such that the cover can occupy a closed position, as illustrated in Figure 1A, and an open position, as illustrated in Figure lB. In this simplified example, the cover comprises two projections 12 which are received by a complementary recess in the frame 14, providing a hinge connection, as shown in Figure 1G.

The cover 10 comprises an inner side 101 which is located inside the manhole openingS when the cover lois in a closed position, and an outer face 103 which is located outside the manhole opening 5 when the manhole cover 10 is in the closed position. Although the cover 10 is illustrated as being rectangular cover, the cover 10 can take any shape. It is common for covers to be square, triangular and circular.

Figures 2 to 4 show a preferred embodiment of a manhole cover supporting device 2, respectively in a side view, an isometric view and operation. The manhole cover supporting device 2 comprises a perimeter engaging portion 20, a manhole cover engaging portion 40 and a supporting member 30.

The perimeter engaging portion 20 comprises a portion 23 having a generally L-shaped cross section. The L-shaped portion 23 comprises a first plate 22 and a second plate 24, each plate being substantially rectangular and being joined, substantially perpendicular to one another, at an edge.

As shown in Figure 4, in operation, the first plate 22 of the perimeter engaging portion 20 engages with a side surface 19 of the manhole frame 14, and the second plate 24 engages with an upper surface 18 of the manhole frame 14 and/or the surface region surrounding the manhole opening 5 into which the frame 14 is installed. This arrangement ensures that the perimeter engaging portion 20 and hence the whole manhole cover supporting device 2 remains substantially stationary and stable with respect to the manhole frame 14. The lengths of the first and second plates are substantially equal to (or lightly less than) the depth of the manhole frame 14 to the upper surface of the lip 16.

In this embodiment, the perimeter engaging portion also comprises a coupling portion 26 attached to the L-shaped portion 23. The coupling portion 26 comprises two substantially semicircular plates in a parallel arrangement with respect to each other (as seen in Figure 3). The coupling portion 26 can be attached to the first plate 22, second plate 24, or both.

The coupling portion 26 and the supporting member 30 are rotatably coupled to one another at a pivot point 29. The two semicircular plates of the coupling portion 26 define a space into which the supporting member extends, such that the plates are disposed either side of the supporting member, and the support member can rotate in a plane that is substantialty parallel to the paraltel to the semicircular plates.

Each of the semicircular plates comprises a plurality of holes 28 each passing through its respective plate and located in axial alignment with a corresponding hole 28 in the other plate. These holes 28 are shaped to accommodate a removable blocking means (such as a rod or bolt) extending from a hole 28 in one semicircular plate to the corresponding hole 28 in the other semicircular plate. Placing such a blocking means through holes of the coupling portion allows the rotation of the supporting member 30 about the pivot point 29 to be restricted.

This is particularly useful for preventing the supporting member from undergoing significant movement relative to the perimeter engaging portion 20 once the cover supporting device 2 is in place supporting the manhole cover 10.

The supporting member 30 comprises two elongate members 31, 32 configured such that one of the elongate members 32 may be slidably received by the other 31 in operation. In this embodiment, the receiving elongate member 31 is coupled to the perimeter engaging portion 23 and the received elongate member 32 is coupled to the cover engaging portion 40.

This allows the overall length of the supporting member to be adjusted, which is useful when using the device 2 to hold different sized drains in an open position.

The supporting member 30 also includes a moveable stopper 33, which is adjustable, in an axial direction along the received elongate member 32, between any number of different fixed positions. The stopper 33 has a cross section wider than an internal diameter of the receiving elongate member 31. Therefore, when the stopper is positioned at a point on the received elongate member 32, the received elongate member 32 may only be received by the receiving elongate 31 member up to the point where the receiving elongate member 31 abuts the stopper 33. In operation, this ensures that the supporting member 30 remains at a constant position when supporting a manhole cover 10.

In this embodiment, the elongate members 31, 32 of the supporting member 30 are generally cylindrical, the received member 32 is threaded about its external surface, and the stopper 33 comprises a complementary internal thread allowing the stopper 33 to be threaded onto received member 32 and positioned appropriately.

The cover engaging portion 40 comprises a clamp portion 42 including a securing clamp bolt 46. The clamp portion 42 is configured to receive an edge pad of the manhole cover which it is intended to support. In this embodiment the clamp portion comprises three substantially rectangular plates, including two outer plates 42a, 42b each attached at an edge to an edge of a connecting plate 42c.

Each of the outer plates 42a, 42b is attached to an opposing edge of the connecting plate 42c. The clamp portion 42 therefore has a generally C-shaped cross section, of a size and shape such that the edge part of a manhole cover 10 can be received by the clamp portion 42. The securing clamp bolt 46 is threaded and, in operation, may be received through the outer plate 42b, via a hole having a complementary thread.

As seen in Figure 4, therefore, the securing clamp bolt 46 is positioned such that, in operation, its end surface 47 can engage with a surface of the manhole cover and an opposing surface of the manhole cover engages with an internal surface of outer plate 42a. This ensures that the manhole cover is held securely by the cover engaging portion 40. Thus, in operation to secure the clamp portion 42 to a manhole cover, the edge part of the manhole cover may be received in the C-shaped cross-section and the clamp bolt 46 tightened to secure the edge pad of the manhole cover in the clamp portion 42.

The clamp portion 42 of the cover engaging portion 40 is pivotally coupled to the supporting member 30 at pivot point 49 via a spacing arm 48 in a plane generally parallel to the plane in which the spacing arm 48 rotates about the perimeter engaging portion 20. Beneficially, the presence of the spacing arm allows the cover engaging portion 40 to rotate about the pivot point 49 with a greater range of motion than if the clamp portion 42 was directly attached to the supporting member.

Modifications and alternatives A detailed embodiment has been described above. As those skilled in the art will appreciate, a number of modifications and alternatives can be made to the above embodiments and variations whilst still benefiting from the inventions embodied therein.

Figure 5 shows a variation in which the cover supporting device is provided with a chain 52 and a securing cable 54. One end of the chain 52 attached at the pivot point 29 and the other end of the chain 52 is attached at pivot point 49. The chain 52 is of a length such that the supporting member 30 can be extended to a maximum desired length but prevents the received elongate member 32 of the supporting member 30 from being fully extracted from the receiving elongate member 31.

One end of the securing cable 54 is attached to the cover supporting device 2 at pivot point 49, and at the other end of the securing cable 54 is disposed a karabiner for coupling 55 the securing cable to a suitable anchor point, like a vehicle or a tree.

It will be appreciated that any suitable retaining mechanism may be used although use of a chain is particularly beneficial. Further, either the chain 52 or the securing cable 54 and attaching means 55 can be omitted from the embodiment illustrated in Figure 5. The chain 52 may comprise any means for attaching the receiving elongate 31 member to the rec&ved elongate member 32.

For example, the chain 52 may comprise a cable. Also, the ends of the chain can be attached at any suitable point, for example one end of the chain could be directly attached to the L-shaped portion.

The securing cable 54 may comprise any suitable means for securing the device to an anchor point (for example a spring clip, hook or other such device). The cable 54 can be provided without the attaching means 55. The securing cable 54 can be attached to any part of the cover supporting device. For example, the securing cable can be attached to the supporting arm of the cover engaging portion 40.

Figures 6A and 6B shows another variation in which the cover engaging portion comprises a foot 62 coupled to the supporting member 30 at the pivot point 49 via a connecting arm 64. The foot 62 comprises a first part 61 and a second part 63, each part consisting of a substantially rectangular plate. The first and second parts 61, 63 are joined to the other at an edge and lie in a plane oriented perpendicularly to the other, to form a substantially L-shaped cross section. The L-shaped foot 62 is connected to the connecting arm 64 such that at least one of the outer surfaces of the foot 62 can engage with the manhole cover 10, as illustrated in Figure 6B. This has the advantage of versatility in that it could be used for a wider range of cover types. The main embodiment, however, provides greater stability and security. It will be appreciated that a plurality of different replaceable cover engaging portions may be provided which can be exchanged depending on the type of manhole cover to be supported.

It will be appreciated that, in some embodiments, the foot 62 of cover engaging portion 40 illustrated in Figures 6A and 6B may be shaped to be received by a complementary recess or protrusion disposed on the manhole cover.

The manhole cover supporting device described above and below may be used to support items other than manhole covers. For example, the device can be used to securely support drain covers and the like in an open position.

With reference to Figure 2 in particular, the perimeter engaging portion 20 may be configured to receive an edge of a manhole opening which is shaped differently to the manhole frame described previously. For example, the perimeter engaging portion 20 may engage directly with the ground, or with another fixed object. In this case the perimeter engaging portion may have appropriately shaped features, for example a fIat foot for engaging with the ground. Alternatively, the perimeter engaging portion 20 may be shaped to engage with the frame of a round manhole, and therefore the surfaces which come into contact with the edge of the manhole would be curved to accommodate the manhole frame.

The first and second plates 22, 24 of the L-shaped portion may lie in planes oriented at any angle with respect to one another depending on requirements. It will be appreciated that a plurality of different replaceable ground engaging portion may be provided which can be exchanged depending on the type of manhole cover to be supported.

The L-shaped portion may have a different configuration. For example, the L-shaped portion may have any form comprising a pair of surfaces arranged perpendicularly or at another angle to each other. The L-shaped portion and coupling portion may be formed as one continuous body. ii

The coupling portion 26 may in fact have a different shape, for example curved, rectangular etc. The coupling portion 26 may simply comprise a pivot point provided directly on the perimeter engaging portion 20 as shown in Figure 7.

The two elongate members 31, 32 may be coupled to one another in any way that allows the overall length of the supporting member to be varied. For example, the elongate member 31 may be internally threaded and the elongate member 32 may be externally threaded, such that the elongate member 32 can be inserted into the elongate member 31 by rotational motion about an axis running parallel to the length of the support member.

Either of the elongate members 31 and 32 may slidably receive the other.

Alternatively, the supporting member may not be configured to allow adjustment of its total length. As shown in Figure 5, the supporting member can be made from a single elongate member, or elongate members making up the supporting member may be fixed with respect to one another. A plurality of different replaceable supporting members, for example of different lengths, may be provided for different applications, e.g. for use with different sizes of manhole cover.

The securing bolt 46 may not be received by the clamp portion 42 in a threaded engagement, but may be otherwise held. For example, the securing bolt 46 may be biased to move towards the inner space defined by the clamp portion via a spring.

The securing bolt 46 may be disposed at either one of the outer plates 42a, 42b, or a securing bolt could be provided in both outer plates 42a, 42b.

Alternatively, the clamp portion may not comprise a securing bolt. In alternative embodiments, the clamp portion may be formed from a resilient material which is configured to securely receive the manhole cover.

The clamp portion 42 of the cover engaging portion 40 is pivotally attached to the supporting member 30 at pivot point 49 via a spacing arm 48. However, the clamp portion may be directly connected to the supporting member.

The perimeter engaging portion 20 may be coupled to the supporting member 30 in an inverted orientation in which the roles of the first plate 22 and second plate 24 are effectively reversed, as illustrated in Figure 8, and in which the coupling portion now extends into the manhole opening 5 with the plate 24 to which it is attached.

It will be appreciated that the cover engaging portion 40 and/or the perimeter engaging portion may be rotatably coupled to the support portion such that it can move in one or more other planes of rotation, for example in a plane substantially perpendicular (or at some other appropriate angle to) the longitudinal axis of the support portion, thereby providing greater manoeuvrability.

An alternative embodiment for a device for maintaining a hinged manhole cover in an open position is herein described with reference to Figures 9a to 9c, 10 and 11.

Figure 9a illustrates a view of a manhole cover support device 900 according to this embodiment, from a rear view. Figures 9b and 9c illustrate the device 900 from top and side views respectively, and Figure 10 illustrates the device 900 from a front view.

As shown, the device comprises a plate 901, the shape of which is generally triangular with truncated corners. A cover engaging portion 903 is attached to a rear face 913 of the plate 901.

The cover engaging portion 903 forms a clamp adapted to securely engage with an inner side 101 and an outer side 103 of a manhole cover 10 when the manhole cover 10 is in an open position. The cover engaging portion 903 includes two protruding clamp plates 903-1 and 903-2 which extend outwards, generally perpendicularly, from the rear face 931 of the plate 901. A gap 905 is defined between the two clamp plates 903-1, 903-2, into which part of the manhole cover 10 can be received. Clamp plate 903-2 is adapted to receive bolts 909 which are movable towards and away from the other clamp plate 903-1, to allow movable engagement of the bolts 909 with the manhole cover to secure the manhole cover 10 in place between the two clamp plates 903-1, 903-2. In this embodiment, the clamp plate 903-2 comprises two threaded holes 940 each able to receive a complementary threaded bolt 909. When part of the manhole cover is located within the gap 905, the bolts 909 can be screwed into the threaded hole, towards the protrusion 903-1, until one side of the manhole cover 10 (e.g. the inner side 101) is in engagement with the clamp plate 903-1 and an opposing side of the manhole cover 10 (e.g. the outer side 103) is in engagement with the bolts 909. In this way, the cover engaging portion 903 is able to securely engage with the manhole cover 10, and maintain the manhole cover in a fixed plane with respect to the cover engaging portion 903.

In this embodiment, the gap 905 is a channel with a generally U-shaped cross section. Shaping the gap in this way allows an edge of a manhole cover 10 to be located within the channel, with the edge running the length of the channel end extending out of each of two opposing ends 905-1 and 905-2 of the channel.

Generally, when the cover engaging portion 903 is engaged with the cover 10, a force will be exerted on the cover 10 by the cover engaging portion 903 and therefore an equal and opposite force will be exerted on the cover engaging portion 903 by the manhole cover 10. In order to help maintain the shape and structural integrity of the engaging portion 903 when under such a force, projection supports 907 are provided, attached to clamp plates 903-1, 903-2 on a side of the respective protrusion which faces away from the gap 905.

One function of the plate 901 is to support the cover engaging portion 903 in a stationary position when the cover engaging portion 903 is engaged with the manhole cover 10. In order to achieve this, the plate 901 includes a base portion 955 for engaging with the ground and/or the manhole frame 14. In this embodiment the base portion 955 is disposed along an edge of the plate 901, and is elongate and substantially straight, allowing engagement with the ground along its length, as the ground it rests upon (usually a road or pavement) will be substantially flat.

The angle defined between the direction in which the base portion 955 extends and the direction which the channel 905 extends dictates the angle at which the manhole cover 10 will be held at with respect to the ground. In this embodiment, the angle between the channel 905 and the base portion 955 is fixed at substantially 90 degrees. However, it will be appreciated that any angle between 0 and 180 degrees may be used, and that the cover engaging portion 903 may be rotatably attached to the plate 901 in order to allow the angle at which the manhole cover 10 is held with respect to the ground to be varied. However, it is preferred that the angle between the channel 905 and the base portion 955 is between 45 degrees and 135 degrees, and more preferably greater than 60 degrees in order to allow easy access to the manhole opening.

In this embodiment, the base portion extends not only along the length of an edge of the plate 901, but also outwards from a front face 933 of the plate 901, forming a lip running around part of the perimeter of the plate 901. The lip, extending outwards from the front face 933, continues around the edge of the plate 901, via truncated corners 951-1 and 951-2 which are each located proximate to the base portion 955. The lip of each truncated corner 951-1 is attached to the lip of the base portion 955, forming an apex 953 defined by the plate 901, the lip of the base portion 955 and the lip of the truncated corner 951-1. A complementary apex is formed at truncated corner 951-2. This construction improves the flexural rigidity and strength of both the plate 901 and base portion 955, while only using a minimal amount of additional material and minimising additional weight of the device 900.

Figure 11 shows the device 900 attached to a manhole cover 10. As shown, the device is located to the side of manhole opening 5, and generally only a small part or none of the device 900 would be located directly above the opening 5.

This allows maximum accessibility to the manhole opening 5. This is particularly the case where the angle between the channel 905 and the base portion 955 is substantially 90 degrees.

Advantageously, the cover engaging portion 903 is aligned with a central point of the base portion 955. This means that, regardless of which side of the manhole cover 10 the cover engaging portion 903 engages with, the base portion will extend in a direction towards the manhole opening 5, inhibiting movement of the manhole cover 10 towards the manhole opening Sand thus maintaining the cover in an open position.

It will be appreciated that the exact form of the base portion 955 can be varied S from the embodiments described. As the function of the base portion is to maintain the position of the cover engaging portion 903 with respect to the ground (or any surface in which the manhole opening is located), the base portion is generally configured to make contact with the ground at points offset from the plane in which the manhole cover is held by the cover engaging portion 903.

In an alternative embodiment, the cover engaging portion 903 is aligned with a point proximate to an end of the base portion 955. This means that the base portion will only extend in a direction towards the manhole opening 5 if the cover engaging portion 903 is in engagement with a particular side (e.g. inner side 101) of the cover 10. However, this embodiment is advantageous because the device 900 can be made smaller, lighter and using less material.

The plate 901 includes three holes 911 each located proximate to an edge of the plate 901. The holes are generally rectangular with rounded ends, and serve as handles for carrying the device 900 by hand. The holes 911 additionally provide attachment points, for example for attaching a safety rope to the device 900.

Furthermore, the holes allow for a reduction in the weight of the device without compromising its structural integrity.

The front face 933 of the plate 901 includes a signage area 961 for attaching or printing signage, in particular affixing warning signs.

The generally triangular shape of the plate 901 is advantageous because the triangle shape is typically used on warning signs, therefore workmen and members of the public will associate the shape with a potential hazard. The combination of a triangular shape and edges including a lip means that the device is adapted to accommodate road signs, for example a triangular "men at work" sign as typically used on British roads. The holes 911 provide attachment points for these road signs, and the lip of the base portion 955 supports the road sign in a fixed position.

While it is stated above that the cover engaging portion 903 may be rotatably attached to the plate 901 in order to in order to allow the angle at which the manhole cover 10 is held with respect to the ground to be varied, this may alternatively or additionally be achieved by the base portion 955 being rotatably attached to the plate.

The base portion 955 may be directly attached to the cover engaging portion 903 without the inclusion of a plate 901. This reduces the overall weight of the device, allowing for easier portability. Additionally, the base portion 955 may be rotatably mounted to the cover engaging portion 903 allowing the angle at which the manhole cover 10 is held to be varied and optionally allowing the device 900 to be folded into a more compact shape for storage and transport purposes.

Figure 12 shows another variation of the manhole cover supporting device, based on the device 2 of Figures 2 to 4. In this alternative embodiment, the device 2 includes a locking bar 120 which is coupled, preferably rotatably, to the L-shaped portion 23 at pivot point 29 of the coupling portion 26, or at another point of the coupling portion 26 or of the L-shaped portion 23.

The locking bar 120 comprises a first elongate member 121 which is configured to slidably receive a second elongate member 122, whereby the length of the locking bar 120 can be varied. Alternatively, the locking bar 120 is variable in length using other means, or is fixed in length.

The locking bar 120 includes a foot 123 disposed at an end of the locking bar 120 distal from the point of connection to the coupling portion 26 (or alternatively the point of connection to the L-shaped portion 23). The foot 123 is provided to allow engagement with an inner side 101 of the manhole cover 10, generally at a point of the inner side 101 proximate to the hinged connection 12 between the manhole cover 10 and the manhole frame 14. The locking bar 120 is configured to brace the device 2 against the manhole cover 10 in order to prevent the device 2 from falling into the opening 5. Alternatively, the locking bar may engage with the manhole frame 14 or another object in order to support the device 2.

Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

Each feature disclosed in this specification (which term includes the claims) and/or shown in the drawings may be incorporated in the invention independently (or in combination with) any other disclosed and/or illustrated features. In particular but without limitation the features of any of the claims dependent from a particular independent claim may be introduced into that independent claim in any combination or individually.

The description of the invention with reference to the drawings is by way of

example only.

Claims (1)

1. <claim-text>Claims 1. A device for maintaining a manhole cover in an open position with respect to a manhole opening, said device comprising: means for engaging with a surface at a perimeter of a manhole opening; means for engaging with the manhole cover in the open position; means for maintaining a separation between the surface engaging means and the cover engaging means such that, in operation, said manhole cover is maintained in said open position.</claim-text> <claim-text>2. A device according to claim I wherein the cover engaging means comprises a clamp for clamping to the manhole cover to secure the device to the manhole cover.</claim-text> <claim-text>3. A device according to claim I wherein the cover engaging means comprises means for supporting the manhole cover in the open position without the need for clamping.</claim-text> <claim-text>4. A device according to any preceding claim wherein the cover engaging means is rotatably coupled to said separation maintaining means.</claim-text> <claim-text>5. A device according to any of claims I to 3 wherein the cover engaging means is fixedly coupled to said separation maintaining means.</claim-text> <claim-text>6. A device according to any preceding claim wherein the surface engaging means is rotatably coupled to said separation maintaining means.</claim-text> <claim-text>7. A device according to claim 6 wherein the surface engaging means comprises means for adjustably restricting the extent to which the separation maintaining means and the surface engaging means can rotate relative to one another.</claim-text> <claim-text>8. A device according to any of claims I to 5 wherein the surface engaging means is fixedly coupled to said separation maintaining means.</claim-text> <claim-text>9. A device according to any preceding claim wherein the surface engaging means comprises a portion for engaging a surface extending into the manhole opening at its perimeter.</claim-text> <claim-text>10. A device according to any preceding claim wherein the surface engaging means comprises a portion for engaging a surface extending away from the manhole at the perimeter of the manhole opening.</claim-text> <claim-text>11. A device according to any preceding claim wherein said separation maintaining means comprises a plate.</claim-text> <claim-text>12. A device according to claim 11 wherein said plate is generally triangular in shape.</claim-text> <claim-text>13. A device according to claim 11 or 12 wherein said surface engaging means comprises an edge of said plate.</claim-text> <claim-text>14. A device according to claim 11 or 12 wherein said surface engaging means comprises a lip extending from said plate (e.g. extending substantially perpendicularly from said plate).</claim-text> <claim-text>15. A device according to any of claims 11 to 14 wherein said cover engaging means is disposed on one face of said plate.</claim-text> <claim-text>16. A device according to any of claims 11 to 15 wherein the device comprises means for displaying signage (e.g. a warning sign).</claim-text> <claim-text>17. A device according to claim 16 wherein the signage displaying means is disposed on a face of the plate.</claim-text> <claim-text>18. A device according to any of claims 1 to 10 wherein said separation maintaining means comprises an elongate member.</claim-text> <claim-text>19. A device according to claim 18 wherein the separation maintaining means is adjustable in length.</claim-text> <claim-text>20. A device according to claim 19 wherein the separation maintaining means comprises a first portion and a second portion coupled to the first portion, and configured for movement relative to the first portion, whereby to provide said adjustability in length.</claim-text> <claim-text>21. A device according to claim 20 wherein the first portion comprises a first elongate member and the second portion comprises a second elongate member received by said first elongate member for movement in a longitudinal direction relative to the first elongate member whereby to provide said adjustability in length.</claim-text> <claim-text>22. A device according to any of claims 20 or 21 further comprising means for limiting the extent to which said second portion can move relative to said first portion to provide said adjustability in length.</claim-text> <claim-text>23. A device according to claim 22 wherein said limiting means comprises means for limiting the maximum extent to which said second portion can move relative to said first portion to provide an increased length.</claim-text> <claim-text>24. A device according to claim 22 or 23 wherein said limiting means comprises means for limiting the maximum extent to which said second portion can move relative to said first portion to provide a shortened length.</claim-text> <claim-text>25. A device according to claim 24 wherein said means for limiting the maximum extent to which said second portion can move relative to said first portion to provide a shortened length is adjustable to change the extent to which said second portion can move relative to said first portion to provide a shortened length.</claim-text> <claim-text>26. A device according to any preceding claim further comprising means for anchoring the device to an anchor point.</claim-text> <claim-text>27. A device according to claim 26 wherein the means for anchoring the device to an anchor point comprises a cable connected to the device and means for releasably connecting the cable to the anchor point. 2!</claim-text> <claim-text>28. A device according to any preceding claim wherein said manhole cover is hingedly connected to a hinged edge of the perimeter of the manhole opening.</claim-text> <claim-text>29. A device according to claim 28 wherein said surface engaging means is configured to engage with a further edge of the perimeter other than the hinged edge.</claim-text> <claim-text>30. A device according to claim 29 wherein said further edge is an edge of the perimeter extending from said hinged edge.</claim-text> <claim-text>31. A device according to claim 30 wherein said further edge is substantially perpendicular to the hinged edge.</claim-text> <claim-text>32. A device according to claim 29 wherein said further edge is opposite the hinged edge.</claim-text> <claim-text>33. A device according to claim 32 wherein said further edge is substantially parallel to the hinged edge.</claim-text> <claim-text>34. A device according to any preceding claim wherein the surface engaging means is configured to engage along a substantial length of the perimeter.</claim-text> <claim-text>35. A device according to any of claims claim 29 to 33, wherein the surface engaging means is configured to engage along a substantial length of said further edge.</claim-text> <claim-text>36. A device according to claim 35 wherein the surface engaging means is configured to engage along more than half of said further edge.</claim-text> <claim-text>37. A device according to claim 28 wherein said device further comprises means for bracing the surface engaging means in a position proximate to the perimeter, wherein said bracing means is coupled to the surface engaging means and configured to engage with the manhole cover at a point proximate to the hinged connection, whereby to brace the surface engaging means.</claim-text> <claim-text>38. A device according to any preceding claim wherein the surface engaging means comprises a base portion shaped to engage with the surface.</claim-text> <claim-text>39. A device according to any preceding claim wherein said device is removably engageable with the manhole cover.</claim-text> <claim-text>40. A device according to any preceding claim wherein said device isportable.</claim-text> <claim-text>41. A device for maintaining a manhole cover in an open position with respect to a manhole opening located in a surface (e.g. a road), said device comprising: a base portion shaped to engage with the surface; and means for securely engaging with the manhole cover in the open position, said cover engaging means being coupled to said base portion and configured to be maintained in a fixed position relative to said base portion, whereby to maintain a manhole cover in an open position with respect to a manhole opening.</claim-text> <claim-text>42. A method comprising using a device of any preceding claim to maintain a manhole cover in an open position.</claim-text> <claim-text>43. A kit comprising pads to assemble a device according to any preceding claim.</claim-text>