GB2506848A

GB2506848A - Manhole cover lifter

Info

Publication number: GB2506848A
Application number: GB201216305A
Authority: GB
Inventors: John Albinson
Original assignee: Hawksley & Sons Ltd
Current assignee: Hawksley & Sons Ltd
Priority date: 2012-09-12
Filing date: 2012-09-12
Publication date: 2014-04-16
Anticipated expiration: 2032-09-12
Also published as: GB2506848B; GB201216305D0

Abstract

A manhole cover lifter 10 comprises a main body portion 12, a lifting key 14 connected to the main body portion 12 adapted for releasable connection to a key-receiving aperture 24 of a manhole cover 28, a fulcrum 36 for engaging a surface 29 adjacent a peripheral edge of the manhole cover 28, and a mechanical lift-assist device 52, 54, 62, 66, 70 urging the main body portion 12 away from the manhole cover 28 to cause the main body portion 12 to rotate about the fulcrum 36 and to prise the manhole cover lifter 10 away from the surface 29. The position of the fulcrum 36 may be adjustable, and may comprise a pair of spaced-apart pins the position of whose ends can be adjusted relative to the main body portion 12. The mechanical lift-assist device may comprise a jacking screw 52 or a cam (92 fig. 5) and a lever 62.

Description

Title: Manhole cover lifter

Description:

This invention relates to a cover lifter, and in particular, but without limitation, to a cover lifter that is suitable for lifting manhole covers.

Manholes exist in a variety of places and provide a convenient means of access to underground utilities, such as pipes and cables. Manholes generally comprise a hole in the ground whose upper periphery is delimited by a surround, usually manufactured from cast concrete or cast iron. To enable pedestrians and vehicles to pass safely over the manhole when not in use, a manhole cover, also known as a manlid, is used to close off and/or seal the hole.

The manhole cover normally comprises a plate or disc of cast iron having a peripheral lip that seats against a corresponding rebated lip of the surround. The upper surface of the manhole cover can be flat, ridged or contoured (where grip is required) or apertured where the manhole cover is designed to allow for ventilation or the passage of rainwater etc. In addition, the upper surface of the manhole cover is normally designed to lie flush with the upper surface of the surround and also the surrounding floor surface.

A manhole cover is usually provided with a number of key apertures located near to its edges for receiving a key, i.e. a tool that comprises a handle at one end and a connector at the other end that can be releasably locked into the key aperture. Manipulation of the key handle whilst engaged with the key aperture of the manhole cover can enable the cover to be lifted and dragged away from the surround.

In certain situations, such as on aircraft runways, taxiways and aprons the manhole cover needs to seat tightly within the surround to inhibit/prevent lifting/displacement of the manhole cover as heavy vehicles and/or aircraft pass over it. As such, the clearance between the manhole cover and the surround can be very small, which can give rise to the cover jamming in the surround.

In addition, where a manhole cover has not been lifted for some time, it is possible for the cover to corrode and/or weld to the surround and/or for the gap between the cover and surround to become clogged by moss, mud and other accumulated debris, thereby making it difficult to lift the cover. This problem can be alleviated, to an extent, by the application of a bead of grease or release agent between the cover and surround, but this practice is not universal and is not always effective over extended periods of time.

Large manhole covers, especially those used in runway, taxiway and aircraft apron applications are necessarily heavy to inhibit and/or prevent lifting of the cover in the wash of fast vehicles and aircraft. In many cases, manhole covers can weigh in excess of 140kg, making them extremely difficult to lift and/or drag by hand.

It should also be borne in mind that two operations are often involved in lifting and manoeuvring a manhole cover, namely: a lifting operation, which often requires very high forces to overcome the jamming/sticking problems previously described; and a manoeuvring operation which requires a lesser force, but generally involves greater amounts of movement.

A tool is therefore required that can operate in two modes, i.e. a first, "high force" mode and a second, "high movement" mode. One example of a known cover lifter is described in US patent number 4126297. This device comprises a main body portion having a handle that serves as a lever for manipulating 5 a key that engages a key aperture of a manhole cover. This device has a pair of fulcrums that engage the floor at different distances from the key, thereby providing two lever ratios. When the handle is pivoted about a first fulcrum located relatively close to the key, a high lifting force can be applied to the key, which provides the first mode of operation mentioned above.

However, if the whole device is rotated, the device can be used in a second mode of operation whereby the second fulcrum can be made to engage the floor at a relatively greater distance from the key than the first fulcrum, thereby providing a lower mechanical advantage than the first mode, but a correspondingly greater range of movement of the key.

In the cover lifter described in US patent number 4126297, a first mode of action, mode 1".

is realised when the key of the cover lifter is inserted into engagement with the socket in the cover and rotated 90 degrees about the socket vertical axis to lock the key into engagement with the cover. In this position a solid fulcrum heel engages on the frame of the cover presenting a very short distance between engaged key and frame. The combination of this short distance of fulcrum heel to the key engagement socket coupled to the long operator handle of the cover lifter results in a significant breaking' force available to debond the cover and surround. In order to achieve the second mode of action, "mode 2", that is to achieve a combined lifting and sliding action to remove the cover from out of the frame, it is necessary to first detach the cover lifter from the cover. The cover lifter and key are rotated back 90 degrees about the socket key vertical axis to unlock the key from cover engagement enabling the cover lifter's key to be removed from the manhole cover.

After rotating the cover lifter to an orientation half a turn away from the original "Mode 1" insertion position, the key of the cover lifter is again inserted into engagement with the socket in the cover and rotated 90 degrees about a vertical axis to lock the key into cover engagement. In this position a wheeled fulcrum heel comes into alignment in such a way that a combined downwards and pulling force on the long handle of the cover lifter causes the cover to rise and slide out of the surround.

Despite the provision, for example, in US4126297, of manhole cover lifters having two lever ratios, it is often the case that the "mode 1" or "high lever ratio" mode provides insufficient force to enable the manhole cover to be lifted from its surround. In particular, a known manhole cover lifter can be capable, through the mechanical advantage effect described above, of providing a vertical lifting force of up to 2 tonnes at the lifting key. However, where the manhole cover has become welded or bonded to the surround through corrosion, even a 2 tonne force can be insufficient to debond the cover from the surround.

A need therefore arises for a manhole cover lifter that is capable of exerting much higher forces to the manhole cover than is currently possible through the use of a hand-operated lever system.

It is an object of this invention to provide such a manhole cover lifter, that provides a "mode 1" lifting facility, a "mode 2" manoeuvring facility and a further mode of operation, namely a "mode 3" operation, in which much higher forces can be applied to break a bonded manhole cover from its surround.

According to a first aspect of the invention, there is provided a cover lifter comprising a cover lifter that is operable in an extreme lifting mode.

The cover lifter is preferably operable in a plurality of modes, the plurality of modes including an extreme lifting mode and either a lifting mode or a manoeuvring mode.

The cover lifter may be operable in the extreme lifting mode by the use of a mechanical assist device, as described generally herein, as distinct from the other modes of operation that rely on manual force exerted directly through a lever.

According to a second aspect of the invention, there is provided a manhole cover lifter comprising: a main body portion; a lifting key connected to the main body portion adapted for releasable connection, in use, to a key-receiving aperture of a manhole cover to be lifted; a fulcrum for engaging, in use, a surface adjacent a peripheral edge of the manhole cover to be lifted, and a mechanical lift-assist device adapted, in use, to cause the main body portion to rotate about the fulcrum to prise the manhole cover lifter away from the said surface, wherein the mechanical lift-assist device cooperates between, and is adapted to urge, the said main body portion away from the said manhole cover to cause the main body portion to rotate about the fulcrum.

Preferably, the lifting key is interposed between the mechanical lift-assist device and the fulcrum: the selection of the distance between the lifting key and the mechanical lift-assist device relative to the distance between the lifting key and the fulcrum determining the mechanical advantage of the manhole cover lifter.

The lifting key is preferably pivotally connected to the main body portion. Advantageously, this enables the lifting key to be folded out of the way when not in use, but also enables the lifting force to be transmitted substantially along the longitudinal axis of the lifting key even as the main body portion is rotated. Such an arrangement can reduce the bending moment on, and hence the likelihood of snapping, in use, the lifting key.

The fulcrum is preferably adjustable. In a preferred embodiment of the invention, the fulcrum comprises a pair of spaced-apart pins the position of whose ends can be adjusted relative to the main body portion. Such a configuration may provide a stable three-point engagement to be obtained between the lifting key acting on the manhole cover and the two fulcrums engaging the surface adjacent the manhole cover.

The mechanical lift-assist device is adapted to cooperate between the main body portion of the manhole cover lifter and the manhole cover. Such a configuration differs in two respects from known manhole cover lifters. Firstly, there is provided a mechanical lift assist device, as opposed to using manually applied forces to the main body portion, for example via a handle or lever. Secondly, the mechanical lift assist device acts between the main body portion and the manhole cover, as opposed to in known manhole cover lifters whereby the lifting force is applied primarily to the lifting key and fulcrum. Whilst the invention and known manhole cover lifters work by canting the main body portion about the fulcrum to raise the lifting key, the invention differs from known manhole cover lifters in that the force is applied to act between the manhole cover and the main body of the manhole cover lifter, rather than applying force to a handle or lever.

The mechanical lift-assist device can be any mechanism that acts to urge a point of the main body portion away from the manhole cover. In other words, the mechanical lift-assist device imparts an expansion force between the main body portion of the lifter and the cover, which can be achieved in any one of a number of ways. For example, the mechanical lift-assist device may comprise a lever-operated cam pivotally connected to the main body portion, such that the cam can be pivoted into engagement, for example using a lever, with the manhole cover to cant the main body portion about the fulcrum. In a preferred embodiment of the invention, the mechanical lift-assist device comprises a jacking screw associated with the main body portion that can be rotated, for example, using a spanner, tommy bar, or other similar tool to bear down on the manhole cover, thereby canting the main body portion about the fulcrum.

The mechanical lift-assist device may optionally include an intermediate member interposed between the jacking screw, cam or other mechanism and the manhole cover, which intermediate member is preferably adapted to encourage or ensure correct application of the lifting force. The provision of an intermediate member may be important, for example, where the manhole cover has an uneven surface, which could lead to slippage of the jacking screw, cam or other mechanical device, which, during the application of very high lifting forces, may present a hazard to operators of the cover lifter. The intermediate device may comprise a slipper that is moveably connected to the main body portion and which comprises means for securely locating and/or restraining the jacking screw, cam or other mechanical device. The slipper may additionally comprise a curved or contoured surface that abuts, in use, the manhole cover, such that forces can be exerted smoothly and/or continuously to the manhole cover during the application of the lifting force as the slipper moves relative to the main body portion.

The cover lifter may additionally comprise a handle such that it can be canted about its fulcrum using manually-applied forces in a similar manner to a conventional manhole cover lifer.

The handle is preferably elongate and preferably extends from the main body portion in a direction that places the handle on the opposite side of the fulcrum to the lifting key.

The manhole cover lifter may additionally comprise tool retainers that can be used for storing tools required for the operation of the cover lifter. For example, a spanner (wrench) retaining clip may be provided for retaining the spanner that operates the jacking screw or the fulcrum adjusters, where either are provided, and or for a tool that can be used for scraping debris from between the manhole cover and its surround. Providing secure tool retainers can ensure that the necessary tools for the correct operation of the manhole cover lifter are always readily available, and can ensure that the said tools are not lost or mixed with other tools that operators may have at the time of use.

The key is preferably adapted to engage a key-receiving aperture of a manhole cover. The key may comprise a generally cylindrical portion and a pair of radially extending tabs that engage with a correspondingly shaped keyhole of the manhole cover to be lifted.

The main body portion of the cover lifter can be manufactured from any suitable material, although a welded steel plate construction may provide the necessary strength, toughness and longevity. The body may comprise a main body portion, e.g. a spine, that provides rigidity and which transmits, in use, the main operating forces between the key and fulcrum. Flexing and/or torsion of the main body portion may be inhibited by additional reinforcing ribs or formations, e.g. webs extending from the main body portion.

The manhole cover lifter may additionally comprise an auxiliary key, which key may be hingedly connected to the main body portion of the lifter so that it can be stowed in a "parked" position when not in use. The auxiliary key may be similar in shape to the main key, although its radial projections may be oriented at right angles to those of the main key.

Preferred embodiments of the invention shall now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of a first embodiment of a manhole cover lifter in accordance with the invention; Figure 2 is a close-up perspective view of the lifter of Figure 1 with one of the side plates removed; Figure 3 is a side view of the lifter of Figure 1 prior to use in an extreme lifting mode; Figure 4 is a side view of the lifter of Figure 4 during an extreme lifting mode opreration; and FigureS is simplified, schematic side view of a second embodiment of a manhole cover lifter in accordance with the invention.

S

In Figure 1, a first embodiment of a manhole cover lifter lOin accordance with the invention is shown, which comprises a main body portion 12, a lifting key 14 and a mechanical lift-assist device 16. The main body portion 12 is formed from a pair of spaced-apart, side plates 18 that provide a gap therebetween within which the mechanical lift-assist device 16 is contained. The use of a pair of spaced-apart side plates 18 serves to create a stiff structure, which is necessary for the application of very high forces to the lifting key 14. The side plates 18 are interconnected by a top plate 20 and an end plate 22, that are connected to the side plates 18 to form a rigid, open-bottomed box-like construction.

The lifting key 14 comprises an elongate shaft 24 having a pair of radially-outwardly extending key formations 26 that form a bayonet-type connector that can releasably engage with a complimentarily-shaped key-receiving aperture 27 of the manhole cover 28. The key 14 can be inserted into the key-receiving aperture 27 and rotated through substantially 90 degrees to interlock therewith in a known manner.

The manhole cover lifter 10 additionally comprises a pair of wheels 30 that can be used to assist dragging the lifter 10 into position using an elongate handle 32 that extends upwardly and away from the body at an angle of approximately 50 degrees. The handle 32 terminates in a curved grip portion 34 at its free end, which enables an operator to grip the handle 32 with the lifter 10 oriented through a range of orientations.

The lifter 10 additionally comprises a pair of downwardly-extending screws 36 whose tips can be adjusted up or down to engage the floor surrounding the manhole cover 28 or its surrounding frame 38. The screws 36 can be adjusted such that they both come into contact with the floor or surround, thereby forming, in conjunction with the key 14, a stable three-point location.

All of the screws and bolts are additionally secured in place using circlips so that they are prevented or inhibited from complete removal, which is an important consideration, in relation to Foreign Object Damage (FaD) when the lifter is used at an airport.

In a first mode of operation, the lifting key 14 is simply inserted into the key-receiving aperture 26 of the manhole cover 28 with the wheels 30 resting on the ground, or surround, adjacent the manhole cover 28. The handle 30 can be pulled upwards, as indicated by arrow 40, to cause the main body 12 of the lifter to cant about the wheels 30, thereby lifting and dragging the manhole cover 28 up and out of its surround. The lifter 10 can then be used, still connected to the manhole cover 28, to facilitate dragging the manhole cover 28 away from the surround. Due to the relatively large horizontal distance between the wheels 30 and lifting key 14, compared to the length of the handle 32, the first mode of operation provides a relatively small amount of mechanical advantage, but conveniently provides a relatively large amount of lifting key 14 movement, which is useful for dragging operations.

An a second mode of operation, the lifting key 14 is inserted into the key-receiving aperture 26 of the manhole cover 28 with the fulcrum screws 36 resting on the ground, or surround, adjacent the manhole cover 28. In this mode of operation, the handle 30 is pulled in the opposite direction, as indicated by arrow 42, thereby causing the main body portion 12 of the lifter to cant about the fulcrum screw tips 36, thereby prising the manhole cover 28 up and out of its surround. In this mode of operation, it will be noted that the horizontal distance between the lifting key 14 and the fulcrums 36 is much smaller than the distance between the lifting key 14 and the wheels 30. Thus, the second mode of operation provides a relatively higher amount of mechanical advantage, which can be used to "break" a jammed manhole cover from its surround.

The invention differs from known manhole cover lifters inasmuch as it provides a yet further mode of operation, an extreme cracking operation mode, which can be used when the manhole cover 28 has become jammed or welded to its surround 29. In such a situation, extreme forces need to be applied to break the manhole cover 28 free from its surround -forces that are impractical to attempt using a conventional manually actuated lever system.

To provide the third mode of operation, the manhole cover lifer 10 of the invention comprises a mechanical lift-assist device 50 that acts between the main body 12 of the lifter 10 and the manhole cover to cant the lifter 10 about the fulcrum screws 36 to provide a much higher prising or lifting force to the manhole cover 28 via the lifting key 14.

In Figure 3 and 4, in particular, it will be seen that the mechanical lift-assist device 16 comprises a jacking screw 52 that is pivotally connected to the main body portion 12 of the lifter 10 via a rotatable trunnion 54. The trunnion 54 comprises a cylindrical steel bar that locates in circular through holes 56 machined into the side plates 18 of the main body 12 of the lifter. The trunnion 54 additionally comprises an internally screw-threaded through aperture, whose thread engages the external thread of the jacking screw 52. The trunnion 54 is inhibited from disengaging the through holes 56 by being prevented from sliding axially by the jacking screw 52. The upper end of the jacking screw 52 emerges from the top of the main body portion 12 of the lifter 10 via a slotted aperture 58 machined into the top plate 20, thus the jacking screw 52 is able to pivot about the centre 60 of the trunnion 54.

The lower end of the jacking screw 52 comprises a rounded end that seats in a curved recess 63 of a slipper 62, which slipper is biased into contact with the tip of the jacking screw 52 by a tension spring 64 affixed at one end to the tip to the slipper 62 and at its other end to a through hole 64 in the main body portion 12 of the lifter 10.

The slipper 62 is pivotally connected, at its opposite end to the jacking screw, to the main body portion via a pin 66 that extends through the side plates 18 of the lifter 10. Thus, by rotating 52 the jacking screw 52, the tip of the slipper 62 moves up, or down into engagement with the upper surface 68 of the manhole cover 28.

The lower tip surface 70 of the slipper 62 is rounded to provide a smooth abutment at it slides over the upper surface 68 of the manhole cover 28 during operation.

In use, lifting key 14 is located in, and engaged with, the key-receiving aperture 27 of the manhole cover 28 and the height of the fulcrum screws 36 adjusted to put the lifting key 14 into slight pre-tension. Then, and as can be best seen in Figure 4, rotation of the jacking screw 52 causes the slipper 62 pivot down and eventually to bear against the upper surface 68 of the manhole cover 28 at a point located on the opposite side of the lifting key 14 to the fulcrum screws 36. The jacking screw 52 is then tightened using a spanner (wrench) and the force causes the lifter 10 to cant about the tips of the fulcrum screws 36 thereby breaking the straight-line relationship between the fulcrums 36, lifting key 14, manhole cover 28 and surrounding surface.

In some instances, it may additionally be necessary to strike the manhole cover 28 with a hammer to cause a shock wave to break the bond, but it will nevertheless be appreciated that the combined mechanical advantages of the spanner (wrench) acting as a lever on the jacking screw 52, the thread of the jacking screw 52 itself and the "class 2" lever effect of the slipper 62 acting on the lifter 10 enables forces many times higher to be applied to the lifting key 14 (with relative ease) than can be accomplished using the "mode 2" operation described above.

The lifting key 14 is able to be folded away, when not in use, by virtue of a friction dished washer that acts between the side of the lifting key 14 and the main body of the lifter 10. The pivotal connection of the lifting key 14 to the main body of the lifter 10 also ensures that the tension in the lifting key 14 is transmitted axially, thus reducing any bending moments that might otherwise snap the key 14.

A yet further mode of operation is possible by using an auxiliary key 90 that is hingedly connected to the body 12 of the lifter 10. It will be noted that the radial projections 26 of the auxiliary key 90 are oriented at right angles to those of the main key lifting 14. The auxiliary key 90 can be used to engage a side pocket of the cover 28 to facilitate the cover's handling. The auxiliary key 90 is connected to the main body of the lifter 10 via a bolt which retains a dished washer and which provides friction between the face of key 90 and the main body 10 so that the key may be stowed in a parked' position.

A second embodiment of the invention is shown schematically in Figure Sin which the mechanical lift-assist device 50 comprises a cam 92 mechanism, rather than a jacking screw 52 as previously described. Identical features have been identified with identical reference signs to avoid repetition. In this case, instead of a jacking screw 52, a cam 92 is provided that can be rotated to cause the slipper 62 to pivot down into engagement with the manhole cover 28. The cam 92 is integrally formed with an elongate handle 94 that lies adjacent the main handle 32 of the lifter when not in use. However, the cam handle 94 can be pivoted about the cam pivot point 96 to cause the cam's surface to bear against the slipper 62 thereby exerting an expanding force between the lifter 10 and the manhole cover 28 to cause the lifter to cant about the fulcrum screws 36 in a manner previously described. Whilst a cam-type lift-assist device may not provide the same mechanical advantage as a jacking screw 52, it can nevertheless, in conjunction with the operation of the slipper 62, provide an increased breaking force to debond the manhole cover 28 from its surround. One of the main advantages of a cam-based mechanical lift-assist device is that it does not require tools, such as a spanner, to operate, and so could, in certain situations, be easier to use.

The invention is not restricted to the details of the foregoing embodiments, which are merely exemplary. For example, the materials and methods of construction could be varied and the geometry of the components changed without departing from the scope of the invention.

Furthermore, whilst the invention has been described with respect to a screw-or cam-based mechanical lift-assist device, any other suitable configuration may be provided.

Claims

Claims: 1. A manhole cover lifter comprising: a main body portion; a lifting key connected to the main body portion adapted for releasable connection, in use, to a key-receiving aperture of a manhole cover to be lifted; a fulcrum for engaging, in use, a surface adjacent a peripheral edge of the manhole cover to be lifted, and a mechanical lift-assist device adapted, in use, to cause the main body portion to rotate about the fulcrum to prise the manhole cover lifter away from the said surface, wherein the mechanical lift-assist device cooperates between, and is adapted to urge, the said main body portion away from the said manhole cover to cause the main body portion to rotate about the fulcrum.
2. A manhole cover lifter as claimed in claim 1, wherein the lifting key is interposed between the mechanical lift-assist device and the fulcrum.
3. A manhole cover lifter as claimed in claim 1 or claim 2, wherein the lifting key is pivotally connected to the main body portion.
4. A manhole cover lifter as claimed in any of claims 1, 2 or 3, wherein the position of the fulcrumis adjustable.
5. A manhole cover lifter as claimed in claim 4, wherein the fulcrum comprises a pair of spaced-apart pins the position of whose ends can be adjusted relative to the main body portion.
6. A manhole cover lifter as claimed in any preceding claim, wherein the mechanical lift-assist device comprises a mechanism that acts to urge a point of the main body portion away from the manhole cover.
7. A manhole cover lifter as claimed in any preceding claim, wherein the mechanical lift-assist device comprises a lever-operated cam pivotally connected to the main body portion, the cam being pivotable, either directly or indirectly, into engagement with the manhole cover to cant the main body portion about the fulcrum.
8. A manhole cover lifter as claimed in any of claims ito 6, wherein mechanical lift-assist device comprises a jacking screw associated with the main body portion that can be rotated bear, either directly or indirectly, on the manhole cover to canting the main body portion about the fulcrum.
9. A manhole cover lifter as claimed in claim 8, further comprising a rotatable trunnion for pivotally connecting the jacking screw to the main body portion.
10. A manhole cover lifter as claimed in claim 9, wherein the trunnion comprises a substantially cylindrical bar that locates in circular through holes in side plates of the main body portion of the lifter, and wherein the trunnion additionally comprises an internally screw-threaded through aperture, whose thread engages an external thread of the jacking screw.
11. A manhole cover lifter as claimed in any of claims 8,9 or 10, wherein an end of the jacking screw extends beyond the main body portion via a slotted aperture to permit, in use, the jacking screw to pivot about the trunnion.
12. A manhole cover lifter as claimed in any of claims 7 to 11, further comprising an intermediate member interposed between the jacking screw, cam or other mechanism, and the manhole cover.
13. A manhole cover lifter as claimed in claim 12, wherein the intermediate member comprises a slipper that is moveably connected to the main body portion and which comprises means for securely locating and/or restraining the jacking screw, cam or other mechanical device.
14. A manhole cover lifter as claimed in claim 13, wherein the slipper is pivotally connected to the main body portion.
15. A manhole cover lifter as claimed in claim 12 or claim 13, wherein the slipper additionally comprises a curved or contoured surface that abuts, in use, the manhole cover.
16. A manhole cover lifter as claimed in any of claims 12 to 15, wherein the intermediate member is biased into contact with the tip of the jacking screw or cam by a spring.
17. A manhole cover lifter as claimed in any of claims 12 to 16, when dependent on any of claims 8 to 11, wherein an end of the jacking screw comprises a rounded portion that seats in a curved recess the intermediate member.
18. A manhole cover lifter as claimed in any preceding claim, further comprising a handle.
19. A manhole cover lifter as claimed in claim 19, wherein the handle is extends from the main body portion in a direction that places the handle on the opposite side of the fulcrum to the lifting key.
20. A manhole cover lifter as claimed in any preceding claim, further comprising one or more tool retainers
21. A manhole cover lifter as claimed in any preceding claim, wherein the key comprise a generally cylindrical portion and a pair of radially extending tabs that engage, in use, with a correspondingly shaped keyhole of the manhole cover to be lifted.
22. A manhole cover lifter as claimed in any preceding claim, further comprising an auxiliary lifting key.
23. A manhole cover lifter as claimed in any preceding claim, further comprising a wheel adapted, in use, to facilitate dragging the lifter into position and as a secondary fulcrum.
24. A manhole cover lifter comprising a cover lifter that is operable in an extreme lifting mode.
25. A manhole cover lifter according to any of claims ito 23, comprising a cover lifter that is operable in an extreme lifting mode.
26. A manhole cover lifter according to claim 24 or claim 25 being operable in a plurality of modes, the plurality of modes including an extreme lifting mode and either a lifting mode or a manoeuvring mode.
27. A manhole cover lifter substantially as hereinbefore described, with reference to, and as illustrated in, the accompanying drawings.