EP2085351A2

EP2085351A2 - Lifting apparatus

Info

Publication number: EP2085351A2
Application number: EP08020419A
Authority: EP
Inventors: Mark Harris
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-01-31
Filing date: 2008-11-25
Publication date: 2009-08-05
Also published as: GB0810941D0; GB0801816D0; EP2085351A3; GB2457064A; GB2449565A; AU2009200054A1; GB2449565B

Abstract

A lifting apparatus comprises a first member (23) having an elongate slot therein and a second member (26) spaced from the first member. A support column (25) extends between the first and second members so as to maintain the first and second members in spaced relationship. First and second securing members (28) are slidably mounted in the slot in the first member on opposite sides of the support column. The securing members include in the region of one end thereof means (33) for engaging with a member (2) to be lifted. The securing members also include in the region of the other end thereof means (31) for engaging with the first member (23). The securing members further include means (29, 30) for adjusting an effective length of the securing member so as to urge the member (2) to be lifted against an underside of the second member (26), the second member being adapted to engage with the member to be lifted between the first and second securing members and in a region beyond each of the securing members.

Description

This invention relates to lifting apparatus, such as may be used to lift a cover of an inspection cover for subsurface drainage and utilities.
It is common practice that subsurface drainage and utilities are accessed by way of inspection chambers, or man entry chambers, which are provided with removable covers to prevent a person or object unintentionally entering such a chamber. Not only does the chamber cover prevent unauthorised access to the chamber, but it also provides a stable surface which allows pedestrians and vehicles to be supported on the cover without any risk of collapse.
Such chamber covers are placed where access is required to subsurface drainage and utilities and are made in many different shapes, sizes, weights and materials. The shape of a chamber cover when combined with its weight can make it difficult safely to lift the cover. In addition, different covers may be lifted in different ways, for example employing different slots and/or depressions in order to engage and lift the cover. For example, some covers have circular holes, others may have two or four lifting slots, and some may be in two pieces. Consequently, it is conventional for a person who requires to lift chamber covers to carry a wide range of ancillary equipment in order to be able to lift a range of covers.
In addition chamber covers are often placed in awkward or hazardous positions where there can be restricted working area. In addition, the surface around the cover can be dangerous, such as uneven, slippery (with water or ice), or sloping.
Various methods are currently used for lifting chamber covers. These include using a pick and shovel, using an array of hand keys which fit into slots and/or depressions in the cover, and employing a range of more sophisticated lifting apparatus. Lifting equipment currently available tends to be relatively heavy, often heavier than the cover itself. Some lifting apparatus also requires assembly at the site of the cover and then must be dismantled in order to be transported to the next site. Often, this also includes lifting the apparatus out of and into a vehicle, which can be difficult and potentially dangerous with heavy equipment. Because of the large range of cover types, it is often necessary to carry additional equipment.
If hand keys are used, two workers will each insert one or more keys into the cover and will then lift the cover, with one worker each side of the cover, using their body strength, probably from a bent or crouched position. This transfers the weight of the cover to the worker's body and can cause injury. The back and knees are at most risk of injury, but almost any part of the body could be injured while lifting or manoeuvring the cover. Moreover, hand keys can slip out of the cover and if this occurs the entire weight of the cover suddenly falls on the worker whose key remains in position.
If a pick and shovel are used, injury can occur if a worker should attempt to grab a slipping cover. Fingers or toes could be crushed or a worker could fall into the inspection chamber, which can be very deep with fast flowing water at its base. Again, the workers tend to be in a bent position in close proximity to the edge of the chamber, and severe stress is placed on the back and knees.
It is therefore an object of the present invention to provide a lifting apparatus which overcomes or at least ameliorates the above drawbacks.
According to the present invention there is provided a lifting apparatus comprising:

a first member having an elongate slot therein;
a second member spaced from the first member;
a support column extending between the first and second members so as to maintain the first and second members in spaced relationship; and
first and second securing members slidably mounted in the slot in the first member on opposite sides of the support column, the first and second securing members including:
- in the region of one end thereof means for engaging with a member to be lifted;
- in the region of the other end thereof means for engaging with the first member; and
- means for adjusting an effective length of the securing member so as to urge the member to be lifted against an underside of the second member,
the second member being adapted to engage with the member to be lifted between the first and second securing members and in a region beyond each of the securing members.

The second member may be substantially in the form of an X-shape. The second member may be provided with stabilising feet which extend at an angle from a central portion of the second member. The stabilising feet may be integral with the central portion of the second member. Alternatively, the stabilising feet may be secured to the central portion of the second member.
The slot may be formed between two separate elongate bars which are secured together in the region of the free ends thereof.
The securing members may be provided with an array of key members for engaging with the member to be lifted. The key members may be rotatable around a substantially horizontal axis to allow selection of a required key member.
The securing members may include a threaded rod secured to the means for engaging with the member to be lifted and a threaded collar engageable with the first member, whereby rotation of the threaded collar relative to the threaded rod adjusts the effective length of the securing means. The threaded collar may be provided with a handle for rotating the collar.
An apertured plate may be arranged between the threaded collar and the first member to serve as the means for engaging with the first member.
The apparatus may include a lifting bar engageable at one end with the first member and having a support means intermediate the ends there of so as to allow the lifting bar to act as a lever. The lifting bar may be engageable with the first member by way of a hook and eye arrangement. The lifting bar may be telescopic in the region of that end engageable with the first member. Additionally or alternatively, the lifting bar may be telescopic in the region of that end thereof remote from the first member.
The support means may comprise a tripod. The tripod may include legs supported on a foot-plate. Alternatively, the tripod may include legs supported on wheels. The length of the tripod legs may be adjustable.
Alternatively, the apparatus may include a handle arranged in the region of each end of the elongate slot for lifting the apparatus.
As a further alternative the apparatus may include a wheeled support arranged in the region of each end of the elongate slot, the wheeled support including means for increasing and decreasing the effective height of the first and second members for lifting an lowering the member to be lifted.
For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which:

Figure 1 is a perspective view of one embodiment of a lifting device according to the present invention;
Figure 2 is a perspective view of a lifting bar forming part of the lifting apparatus of Figure 1;
Figure 3 is a perspective view of a lifting cradle forming part of the lifting apparatus of Figure 1;
Figure 4 is a perspective view of part of the lifting cradle shown in Figure 3;
Figure 5 illustrates the manner in which legs forming part of the lifting bar of Figure 2 are adjusted;
Figure 6 is a perspective view showing a part of the lifting bar of Figure 2;
Figure 7 is a perspective view of part of the lifting cradle shown in Figure 3;
Figure 8 illustrates a modification to legs of the lifting bar shown in Figure 2;
Figure 9 is a perspective view of an embodiment of a modified lifting apparatus according to the present invention;
Figure 10 is a diagrammatic illustration of a modification to the lifting apparatus shown in Figure 1; and
Figures 11 and 12 are plan views of modifications of part of the lifting cradle shown in Figures 1, 3, 7 and 9.

The lifting apparatus shown in Figures 1 to 8 comprises a lifting cradle 3 positioned at an end of a lifting bar 4 which in turn is supported on a tripod 5.
The lifting bar 4 is telescopic on either side of the tripod 5 and comprises a main central section 8, for example of aluminium tube, with a hook bar 7 slidably mounted within one end of the central section and securable at a number of relative axial positions by means of holes passing through both the inner and outer tubes and a locking pin 12 removably inserted through holes in both the inner and outer tubes. A lifting hook 6 is provided in the region of the free end of the hook bar 7. Adjustment of the effective length of the lifting bar 4 allows a worker to ensure that the cover 2 does not hit legs of the tripod when a cover 2 is raised. The cover 2 may be an inspection chamber cover (such as a manhole cover, or a gulley cover, a grating or a similar component that requires to be lifted. A lifting bar 9 is slidably mounted within the other end of the central section 8 and is securable at a number of relative axial positions to allow a worker to adjust the amount of leverage available for lifting the cover 2. The lifting bar 9 can be secured at any one of a number of relative axial positions by means of a locking pin 10 which is removably inserted through holes provided in both the inner and outer tubes. If required, the lifting bar 9 can be removed entirely for storage or transportation purposes. As shown in Figure 6, the outermost ends of the hook bar 7 and/or the lifting bar 9 are provided internally with an elongate bar 13 which extends within and is secured to the tube and is arranged in an upright configuration so as to reinforce the tube and to allow it to resist bending and snapping.
The central section 8 is mounted on the tripod 5 by way of a yoke 14 by way of a removable locking pin 15 which passes through holes provided in both the yoke and the central section 8. The locking pin allows the lifting bar to pivot upwardly and downwardly but can be removed to allow the lifting bar to be separated from the tripod for storage and transportation. The yoke 14 is attached to a head 16 by means of a bolt (not shown) so as to allow the yoke, with the lifting arm attached, to swivel around the tripod through 360 degrees. This provides significant manoeuvrability so that the chamber cover 2, once lifted, can be deposited a safe distance away from the chamber 1 to prevent the cover slipping back into the chamber.
Each tripod leg 17 is attached to the tripod head 16 by way of a bolt 18 or pin which allows pivoting about a generally horizontal axis so as to allow for adjustment of the position of the leg during use and to allow the legs to collapse together for transportation and storage. A safety chain 19 interconnects each of the legs 17 at a level beneath the tripod head 16 to a centrally arranged plate 20 to increase stability and to prevent the tripod legs splaying beyond a predetermined amount. This, in turn, allows greater weights to be lifted safely. Each tripod leg 17 is independently height adjustable as shown in more detail in Figure 5. As can be seen, each tripod leg is provided with a foot-plate 21 which is slidably mounted within the leg and can be secured at a number of different relative positions by way of holes provided through the tripod leg and through the foot-plate to enable a locking pin 22 to secure the tripod leg and foot-plate in position. The base of the foot-plate is substantially flat and serves to distribute the weight of the apparatus to reduce the likelihood of causing marks on surfaces on which the tripod is placed or sinking into relatively soft surfaces.
The lifting cradle 3 is shown in more detail in Figure 3 and comprises a pair of spaced elongate bars 23 so as to create an elongate slot between the two bars. The spaced bars could be replaced by alternative elongate means defining an elongate slot, but the spaced bars have been found to be particularly effective. The length of the spaced bars is chosen to be sufficiently long so as to exceed the maximum dimension of a chamber opening so as to prevent the chamber cover falling into the chamber in the event of slippage. The slot is closed at the free end of the bars by a locking pin arrangement 11 which passes through holes formed through the bars 23. A lifting eye 24 is mounted on the spaced bars substantially midway between the ends thereof and serves to connect the lifting cradle 3 with the hook 6 of the lifting bar 4. In practice, the lifting eye is secured to a plate by way of securing nuts and the plate is secured to the spaced bars by way of rivets. The spaced bars may be of hollow aluminium tube, for example of square cross-section, while the lifting eye may be of high strength plated steel. The lifting eye allows the lifting cradle to swing freely from the lifting bar and therefore allows the cover 2 to become level and balanced so as to facilitate lifting and repositioning of the cover.
Two upright bars 25, for example hollow bars of square cross-section, extend downwardly from the elongate bars, one on each side of the lifting eye 24, and connect the elongate bars to a base plate 26. It should be noted, however, that the number of upright bars can be varied and can be one or more. The base plate is provided with stabilising feet 27 which increase the effective area of the base plate while covering a relatively small proportion of the surface of the cover 2 so as to allow access to the remainder of the surface of the cover. Advantageously, the stabilising feet 27 extend outwardly from corner regions of the base plate, for example at about 30 degrees to an elongate direction of the base plate. The stabilising feet assist in preventing split covers from parting and falling into the chamber 1 when the cover is lifted. Part of the arrangement of the upright bars 25, base plate 26 and stabilising feet 27 is shown in more detail in Figure 7. As can be seen, the stabilising feet are provided with elongate, upwardly extending ribs to reinforce the feet. The stabilising feet are secured to the base plate with blind rivets and the upright bars are secured to the base plate by way of angle brackets which are secured to both the upright bar and to the base plate with blind rivets.
A securing mechanism 28, shown in more detail in Figure 4, is mounted outwardly of each of the upright bars 25 in a manner which allows the securing mechanisms to slide along the slot between the two elongate bars 23 so as to allow the space between the securing mechanisms to be adjusted for different covers. Each securing mechanism comprises an upright threaded bar 29, for example of stainless steel, which has a threaded collar 30 mounted thereon and movable upwardly and downwardly along the bar 29 as a result of rotation of the collar by suitable handle means, such as one or more short bars extending from the collar. An apertured plate 31 is provided beneath the collar 30 for transmitting the load of the securing mechanism to the elongate bars. A handle 32, for example in the form of a closed loop, is provided at the upper end of the threaded bar to facilitate lateral movement of the securing mechanism. The lower end of the threaded bar 29 is provided with a multi-headed key system 33 which includes a plurality of different keys mounted for rotation about a generally horizontal axis so as to allow an appropriate key to be selected for the cover 2 to be lifted. For example, the keys may be made of steel and mounted within an inverted U-shaped member attached to the lower end of the threaded bar. In order to secure the lifting cradle to a cover, the appropriate key is selected for each of the slots in the cover and inserted into the slots. With the securing mechanisms in a desired position along the elongate bars, the collars 30 are then rotated so as to shorten the effective length of the threaded bar so that each threaded bar 29 is in tension, while each upright bar 25 is in compression. In this way, the lifting cradle 3 is effectively clamped to the cover 2.
The securing mechanism may, for example, be provided with three keys, one with a relatively large T-shaped head, one with a relatively small T-shaped head and one with a hook-shaped head. Such a selection of keys has been found to fit the vast majority of covers in common usage.
The arrangement of the base plate 26 and the stabilising feet 27, for example the length of the stabilising feet, is such that the base plate and/or the stabilising feet extend outwardly beyond the securing mechanisms 28 for all commonly available chamber covers. In this way, when the securing mechanisms are tightened, the base plate/stabilising feet arrangement acts in regions of the cover both between the securing mechanisms and in a region beyond each of the securing mechanisms. This arrangement serves to support even a split cover, for example as shown in Figure 1, securely.
In situations where the chamber cover 2 is in an area that has limited space and simply moving the cover to one side is not feasible, then the foot-plate 21 can be replaced with a wheel arrangement 34 which allows the lifting apparatus to be wheeled away from the chamber 1 once the chamber cover 2 has been lifted and to be wheeled back into position when the chamber cover is to be replaced.
In use of the lifting apparatus, the lifting cradle 3 is first secured to the chamber cover 2 by inserting the desired key from the securing mechanism 28 and ensuring the securing mechanisms are in a desired position along the slot between the elongate bars 23. The collar 30 is then tightened until the base plate 26 and stabilising feet 27 are as flat and tight against the cover 2 as possible.
The lifting bar 4 is then attached to the lifting cradle 3 by way of the hook 6 and lifting eye 24.
The tripod is then arranged with all three feet 21 in contact with the ground and the tripod head 16 substantially level and at a suitable distance from the chamber 1. If necessary, the tripod legs 17 can be lengthened or shortened to ensure the tripod is safe and level.
Downward pressure is then applied to the lifting bar 4, with the operator simply using his body weight, with the result that the lifting cradle 3 is raised with the cover 2 attached. In the event the cover is too heavy to lift comfortably, the length of the lifting bar can be increased to increase leverage, but if the cover 2 is jammed or stuck it will need first to be eased with a pry bar and/or hammer.
When the cover has been lifted clear of the chamber 1 the cover 2 and lifting cradle 3 can be pivoted to one side of the chamber and lowered in order that the chamber can be inspected.
Replacement of the cover is essentially a reverse of the removal procedure.
Thus the present invention provides a lifting apparatus which, being made primarily of aluminium, is relatively light. Moreover, the apparatus comprises a number of separate major components (lifting cradle, lifting bar and tripod) which can be assembled and dismantled quickly and easily. The result is that the lifting apparatus can readily be transported in a car or small van and can readily be moved to and away from the site of the chamber cover.
Importantly, because the user employs only body weight to lift the cover, the risk of injury to the user is very significantly reduced.
The lifting apparatus may be modified in a number of ways. For example, as shown in Figure 9 the lifting cradle 3 may be used without the lifting bar 4. Instead, a handle 35 is mounted on the locking pin arrangement 11 at each free end of the elongate bars 23. As illustrated, the handle comprises a bar having an aperture at that end engaging with the lifting cradle and a transverse hand grip at the free end. If desired the handle may be telescopic, for example in the manner previously described for the lifting arm, or the bar may be replaced by a chain or the like.
As shown in Figure 10, a wheel arrangement 36 can be provided at the ends of the elongate bars 23 of the lifting cradle 3 to lift and move the cover 2. The wheel arrangement has a lateral tubular member 37 which fits over the elongate bars 23 and has apertures to receive the locking pin arrangement 11. The wheel arrangement also includes an upright tubular member 38 which has a further tubular member 39 slidably located therein an movable downwardly and upwardly by means of a threaded rod 40 rotatably mounted to the tubular member 39 and a threaded collar 41 mounted on the tubular member 38. The threaded rod 40 is rotatable by a handle 42 mounted securely on the rod. A pair of spaced wheels 43 are mounted at the lower end of the further tubular member 39 to allow movement of the lifting apparatus.
In use, a wheel arrangement is attached at each end of the elongate bars 23 of the lifting cradle 3 with the lifting cradle raised through rotation of the handle 42. The lifting cradle can then be positioned over a cover 2 and lowered so that the base plate 26 contacts the cover. The lifting cradle is then secured in position on the cover as described previously and is raised, not with a lifting bar or handle, but by turning the threaded rod 40 with the handle 42. In this way the cover can be lifted from the chamber without any significant effort and can be moved to a desired location by the wheels 43 simply by pushing the lifting apparatus.
Replacement of the cover is simply a reverse of the lifting procedure.
Figures 11 and 12 show different forms of base plate. In Figure 11 the stabilising feet 27 are integral with the remainder of the base plate 26 with the base plate arrangement being in an X-shape. In Figure 12, the stabilising feet 27 are separate from the base plate 26, the stabilising feet at each end of the base plate being provided by a member of substantially U-shape or substantially horseshoe-shape configuration. Clearly the base plate/stabilising feet arrangement can have many different configurations.

Claims

A lifting apparatus comprising:
a first member (23) having an elongate slot therein;

a second member (26) spaced from the first member;

a support column (25) extending between the first and second members so as to maintain the first and second members in spaced relationship; and

first and second securing members (28) slidably mounted in the slot in the first member on opposite sides of the support column, the first and second securing members including:
in the region of one end thereof means (33) for engaging with a member (2) to be lifted;

in the region of the other end thereof means (31) for engaging with the first member (23); and

means (29, 30) for adjusting an effective length of the securing member so as to urge the member (2) to be lifted against an underside of the second member (26),

characterised in that the second member is adapted to engage with the member to be lifted between the first and second securing members and in a region beyond each of the securing members.
An apparatus as claimed in claim 1, characterised in that the second member (26) is substantially in the form of an X-shape.
An apparatus as claimed in claim 2, characterised in that the second member (26) is provided with stabilising feet (27) which extend at an angle from a central portion of the second member.
An apparatus as claimed in claim 3, characterised in that the stabilising feet (27) are integral with the central portion of the second member (26).
An apparatus as claimed in claim 3, characterised in that the stabilising feet (27) are secured to the central portion of the second member (26).
An apparatus as claimed in any preceding claim, characterised in that the slot is formed between two separate elongate bars (23) which are secured together in the region of the free ends thereof.
An apparatus as claimed in any preceding claim, characterised in that the securing members (28) are provided with an array (33) of key members for engaging with the member (2) to be lifted.
An apparatus as claimed in claim 7, characterised in that the key members are rotatable around a substantially horizontal axis to allow selection of a required key member.
An apparatus as claimed in any preceding claim, characterised in that the securing members (28) include a threaded rod (29) secured to the means (33) for engaging with the member (2) to be lifted and a threaded collar (30) engageable with the first member (23), whereby rotation of the threaded collar relative to the threaded rod adjusts the effective length of the securing means.
An apparatus as claimed in claim 9, characterised in that the threaded collar (30) is provided with a handle for rotating the collar.
An apparatus as claimed in claim 9 or 10, characterised in that an apertured plate (31) is arranged between the threaded collar (30) and the first member (23) to serve as the means for engaging with the first member.
An apparatus as claimed in any preceding claim, characterised in that a lifting bar (4) is engageable at one end with the first member (23) and has a support means (5) intermediate the ends thereof so as to allow the lifting bar to act as a lever.
An apparatus as claimed in claim 12, characterised in that the lifting bar (4) is telescopic in at least one of the region of that end engageable with the first member (23) and the region of that end thereof remote from the first member.
An apparatus as claimed in any one of claims 1 to 11, characterised in that a handle (35) is arranged in the region of each end of the elongate slot for lifting the apparatus.
An apparatus as claimed in any one of claims 1 to 11, characterised in that a wheeled support (36) is arranged in the region of each end of the elongate slot, the wheeled support including means (40, 41, 42) for increasing and decreasing the effective height of the first and second members (23, 26) for lifting an lowering the member (2) to be lifted.