GB2539505A

GB2539505A - Improvements in or relating to lifting apparatus

Info

Publication number: GB2539505A
Application number: GB1510858.2A
Authority: GB
Inventors: Norman Tolley Keith
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-06-19
Filing date: 2015-06-19
Publication date: 2016-12-21
Anticipated expiration: 2035-06-19
Also published as: GB2539505B; GB201510858D0

Abstract

Lifting apparatus 10 for use in lifting a planar member 12 such as a lid for a railway cabling service duct, a paving slab or a manhole cover which has first and second opposed edge regions 14, 16 comprises: a releasable arrangement 20 to hold the planar member 12; a first pivot portion 22 providing a first horizontal pivot axis 24 for turning the apparatus 10 to raise a first edge region 14 of the planar member 12; and a base member 26 which can move to a position below the raised first edge region 14 to provide a supportive base for the apparatus 10, wherein the base member 26 serves to support the first edge region 14 in the raised position and provides a second horizontal pivot axis 28 for raising the second edge region 16 while the first edge region 14 remains raised. The releasable arrangement 20 may clamp the planar member 12 between relatively pivotable first and second jaws 30, 32 which may be held in position by a lock including a latching, collapsible arm 56. A long arm 52 and grip 54 may form a handle. The base member 26 may include at least one wheel and a foot portion 66 which may fit over a structure such as the wall of a duct 18.

Description

Improvements in or relating to lifting apparatus The present invention relates to lifting apparatus. Examples of apparatus will be described for use in lifting a generally planar member.

Various situations exist in which it is necessary to raise a generally planar member. Examples include lids of service ducts such as are used to contain cabling along railway tracks. Other examples include paving slabs and manhole covers. In each of these examples, and others, the planar member is heavy and is awkward for manual lifting. This creates danger for workmen, particularly a risk of injury. Various proposals have been made for apparatus to assist in lifting these items. These proposals have been unsatisfactory for various reasons, which may include a lack of ease of use, or a lack of convenience, or inadequate safety achieved.

Examples of the present invention provide lifting apparatus for use in lifting a generally planar member which has first and second generally opposed edge regions; the apparatus comprising: a releasable arrangement operable, in use, to hold the planar member; a first pivot portion providing, in use, a first generally horizontal pivot axis for turning the apparatus to raise a first edge region of the planar member; and a base member which, in use, can move to a position below the raised first edge region to provide a supportive base for the apparatus, wherein the base member serves to support the first edge region in the raised position and provides, in use, a second generally horizontal pivot axis for raising the second edge region while the first edge region remains raised.

The releasable arrangement may be operable to clamp the planar member between first and second jaws. The first and second jaws may be pivotally connected to turn relative to one another between a clamp position and a release position. The apparatus may further comprise a lock arrangement operable to lock the releasable arrangement. The lock arrangement may include a collapsible arm connected between the jaws, to control the relative positions of the jaws. The collapsible arm may have an over-centre action to lock the jaws against a planar member. There may be a latch mechanism operable to lock the collapsible arm, thereby locking the relative positions of the jaws.

The first jaw may provide the first pivot portion. The first pivot portion may be an extremity of the first jaw, on which the lifting apparatus can rock. One of the jaws may have an extension which serves, in use, as a handle for rocking the apparatus about the horizontal pivot axes.

The base member may be movable relative to the rest of the apparatus by pivoting.

When the base member has moved below the raised first edge, in use, the rest of the apparatus may be pivotable on the base member to raise the second edge region. The second pivot axis for raising the second edge may be the same as the pivot axis for moving the base member below the raised first edge region.

The base member may have a foot which supports the apparatus when the base member is below the raised first edge. The foot may be shaped to fit over a structure below the raised first edge, to retain the apparatus in position on the structure.

The base member may have at least one wheel which is positioned to engage the 20 ground when the base member is under the raised first edge portion, to allow the apparatus and the planar member to be moved while supported on the wheel or wheels.

The position of the second pivot axis relative to the base member may allow the 25 combined centre of gravity of the apparatus and the planar member to be moved past the second pivot axis.

Examples of the present invention will now be described in more detail, by way of example only, and with reference to the accompanying drawings, in which: Fig 1 illustrates an example apparatus in use, in an initial condition; Fig 2 is a partial plan view of the apparatus of Fig 1; Fig 3 is an elevation view of the base member of the apparatus of Fig 1; Fig 4 is an elevation view of one example of a first jaw of the apparatus of Fig 1; Fig 5 to Fig 8 illustrate the apparatus of Fig 1 in various conditions, to illustrate the sequence of use of the apparatus; and Figs 9 and 10 illustrate an alternative locking arrangement forming part of the apparatus.

Overview The drawings illustrate a lifting apparatus 10 for use in lifting a generally planar member 12 which has first and second generally opposed edge regions 14, 16. In this example, the planar member 12 is a lid of a service duct 18 of the type commonly used alongside railway tracks to contain cables or other services. The planar member 12 and the service duct 18 are cast in concrete for strength. The lid 12 is therefore heavy and may be too heavy for manual handling, or sufficiently heavy to require at least two workmen for safe manual handling.

The apparatus 10 comprises a releasable arrangement indicated generally at 20 and operable, in use, to hold the planar member 12, as will be described. A first pivot portion 22 provides, in use, a first generally horizontal pivot axis 24 for turning the apparatus 10 to raise a first edge region 14 of the planar member 12. The apparatus 10 also has a base member 26 which, in use, can move to a position below the raised first edge region 14 (to be described in more detail with reference to later figures). When moved below the first edge region 14, the base member 26 provides a supportive base for the apparatus 10, as will be described. In this condition, the base member 26 serves to support the first edge region 14 in the raised position and provides, in use, a second generally horizontal pivot axis at 28 for raising the second edge region 16 while the first edge region 14 remains raised.

The planar member 12 will hereafter be referred to simply as a "lid", in the interests of brevity. It is to be understood that the planar member 12 could alternatively be a paving slab, manhole cover or other planar member. In these examples, the planar member 12 will generally be square or rectangular in shape, therefore having generally straight and generally parallel opposed edges. Other shapes of planar member 12 may have non-linear opposed edge regions, such as curved edge regions. It will be readily apparent to the skilled reader, having properly understood the contents of this specification, that the apparatus being described can be simply modified to allow its use with various different shapes and sizes of planar member, including planar members with non-linear opposed edge regions.

Structure of the apparatus The releasable arrangement 20 is here in the form of a clamp having a first jaw 30 and a second jaw 32. The jaws 30, 32 are pivotally connected and in this example, the pivotal connection is at the second horizontal axis 28. Fig. 1 shows the shape of the jaws 30, 32 in elevation. Each of the jaws 30, 32 is formed by two, spaced apart components cut from sheet material, as can be seen in Fig 2 (in which the first jaw 30 is only partially illustrated). The pivotal connection at 28 between the jaws 30, 32 is provided by a nut 36 and bolt 38.

The first jaw 30 has a main limb 40 which, in use, initially extends generally horizontally across the top of the lid 12 (Fig. 1). The main limb 40 carries a first claw 42 which extends down by the second edge region 16 and has a first hook which forms the first pivot portion 22 and can reach under the lid 12. The main limb 40 may also have feet 46, such as rubber bumpers, to rest on the lid 12.

The second jaw 32 has a second claw 48 with a second hook 50. The second claw 48 is shown in a raised condition in Fig 1. The second jaw 32 also has a relatively long arm 52 which extends away from the axis 22 to a grip region 54, providing a handle for manipulating the apparatus 10, as will be described. The arm 52 may be telescopic for length adjustment.

A collapsible arm 56 extends between the jaws 30, 32. The arm 56 is pivotally connected to the jaws 30, 32 at 58 and has a further pivot connection 60, part way along it, allowing the arm 56 to adopt a folded or collapsed condition (Fig. 1) or to be extended to a condition illustrated in Fig 5. As the arm 56 is extended, the jaws 30, 32 turn relative to one another, bringing the claws 42, 48 toward each other. This allows the lid to be releasably held between the jaws 30, 32, as will be described in more detail below.

The base member 26 is illustrated separately in Fig 3 and is formed by two, spaced apart components cut from sheet material (as can be seen in Fig 2). The base member 26 has a pivot arm 62 having a hole 64 at one end for receiving the bolt 38 to mount the base member 26 at the axis 28. The base member 26 has a foot portion 66. In this example, the foot portion 66 includes a generally rectangular cutout 68, having dimensions suitable to receive the wall of the duct 18, as will be described. A set screw arrangement 70 (Fig 3) may be provided to adjust the width of the cutout 68, for example to accommodate different designs of duct 18. The two components of the base member 26 are connected by a handlebar 72 which may conveniently be used for carrying the apparatus 10, when not in use.

The base member 26 is pivotable about the horizontal axis 28, as has been described, but may be provided with a simple catch arrangement 74 to hold the base member 26 in a stowed position against the second jaw 32.

Alternative arrangement for the first jaw In Fig 1 and other drawings, the first jaw 30 is illustrated as having a fixed length. This will allow the apparatus 10 to be used with a single size of lid 12. Fig 4 illustrates an alternative arrangement in which the length of the first jaw 30 is adjustable. In this example, the first claw 42 is slidably mounted on the main limb 40 by means of a sliding pin 76 running in a slot 78, and a fixing bolt or other equivalent arrangement securing the position of the first claw 42 along the limb 40 by engagement with a chosen one of a line of holes 80 formed along the limb 40. This allows the apparatus 10 to be simply adjusted to accommodate a different size of lid 12, by engaging with a different selection of hole 80.

Raising the lid Having described the structure of the apparatus 10, its manner of use in raising the lid 12 can now be described in more detail.

The first step is to rest the apparatus 10 on the lid 12, with the apparatus 10 in the folded condition illustrated in Fig 1. The second jaw 32 is folded down onto the first jaw 30, with the arm 56 in the collapsed condition. This sets the claws 42, 48 apart, which corresponds with a release position of the jaws 30, 32. Consequently, the first claw 42 can readily be brought alongside the second edge region 16 to engage the hook 44 under the edge region 16. While this is done, the base member 26 is held out of the way, by the catch arrangement 74.

Next, the second jaw 32 is raised, for example by gripping the grip region 54 and lifting the arm 52. This also turns the second claw 48 around the axis 28, bringing the second claw 48 against the first edge region 14, with the second hook 50 under the edge region 14. The collapsible arm 56 extends as the second jaw 32 is raised.

When the collapsible arm 56 is fully extended, further movement of the second jaw 32 is arrested. In this example, this will correspond with the claws 42, 48 both engaging their respective edge regions 14, 16 and this allows the collapsible arm 56 to perform an over-centre action to force the claws 42, 48 to grip tightly against the edge regions 14, 16 and to lock the arrangement 20 in this condition by virtue of the over-centre action of the collapsible arm 56. Thus, the collapsible arm 56 serves as a lock arrangement for the releasable arrangement 20.

The apparatus 10 is now mounted on the lid 12 by tightly gripping the lid 12 between 25 the claws 42, 48 and with the hooks 22, 44 under the edge regions 14, 16. This corresponds with a clamp position of the jaws 30, 32.

In reaching the condition illustrated in Fig 5, the catch arrangement 74 has been released to allow the base member 26 to swing down around the axis 28 to lie loosely alongside the duct 18.

Having locked the apparatus 10 into engagement with the lid 12, as has just been described, and with the arm 52 reaching up to position the grip region 54 above the lid 12, the apparatus is now in condition to begin lifting the lid 12 by pushing on the grip region 54 in the direction of the arrow 82. This direction of push is generally away from the second claw 48 and generally toward the first claw 42. In consequence, since the lid 12 will be too heavy to slide on the duct 18, and/or will have engaging lips or the like to maintain alignment on the duct 18 and thus to prevent sliding on the duct 18, this action of pushing on the grip region 54 will cause the apparatus 10 and the lid 12 to begin to rock about the horizontal axis 24 defined by the hook 22 resting on the duct 18. That is, the extremity of the first claw 42, at the hook 24, rests on the top of the duct 18 and serves as a pivot on which the apparatus 10 can rock. This causes the first edge region 14 to be raised to the condition illustrated in Fig. 6.

As the first edge region 14 is raised, the base member 26 is free to swing down further to the position illustrated in Fig. 6, in which the base member 26 has moved to a position below the raised first edge region 14. No manual intervention is necessary in order for this movement of the base member 26 to occur, because the base member 26 is free to turn around the axis 28 and will therefore move to the position of Fig 6 by the effect of gravity.

Once the condition of Fig. 6 has been attained, the first edge region 14 can be lowered gently back toward the duct 18. However, the interposition of the base member 26 will not allow the lid 12 to return to the original position on the duct 18. Rather, as the first edge region 14 is lowered, the foot portion 66 of the base member 26 will come to sit on the wall of the duct 18 (Fig 7), with the top edge of the duct 18 received snugly in the cutout 68.

When the condition of Fig 7 has been attained, the first edge portion 14 is supported by the base member 26, slightly above the duct 18. That is, the lid 12 is slightly inclined. The base member 26 sits securely on the duct 18, by virtue of the cutout 68. The grip region 54 can now be pulled in the opposite direction as compared with the arrow 82 in order to swing the jaws 30, 32 around the axis 28. While this occurs, the base member 26 provides a supportive base for the apparatus 10, sitting securely on the edge of the duct 18. The wide separation of the plates of the base member 26 (Fig 2) contributes to the security of the seating. As the jaws 30, 32 swing around the axis 28, the second edge region 16 is raised. The first edge region 14 remains supported in the raised position by the base member 26.

This movement can continue until the condition of Fig 8 has been reached, in which the apparatus 10 and the lid 12 have turned through an angle of around 135°, until the second jaw 32 again meets the handlebar 72, causing the catch arrangement 74 to engage. The angle of movement is also sufficient for the combined centre of gravity of the apparatus 10 and the lid 12 to have moved from the duct side of the axis 28, to the opposite side of the axis 28. The arrangement is therefore able to sit stably in the condition of Fig 8, partly by virtue of the supportive base provided by the base member 26, partly by virtue of the engagement of the catch arrangement 74, and partly by virtue of the position of the combined centre of gravity. Consequently, the interior of the duct 18 can now be accessed safely, with the lid 12 held stably in the open condition of Fig 8.

Closing the lid When it is desired to close the lid 12, a sequence which is generally the reverse of the sequence described above can be used to achieve a safe and controlled closure of the lid 12. More particularly, with the grip region 54 held by hand, the catch arrangement 74 can be released either by hand or by foot, allowing the apparatus 10 and the lid 12 to swing back from the condition of Fig 8 to the condition of Fig 7. The first edge region 14 can then be raised by pivoting around the first axis 24 to the condition of Fig 6. This allows the base member 26 to be removed from under the first edge region 14 and engaged again with the catch arrangement 74, allowing the lid 12 to return to the closed position of the condition of Fig 5 (but noting that in Fig 5, the base member 26 is shown disengaged from the catch arrangement 74, whereas the base member 26 and the catch arrangement 74 will be engaged when the lid is being replaced).

Finally, the collapsible arm 56 can be released against it over-centre action to fold the apparatus 10 down to the condition of Fig 1 and thus to allow the apparatus 10 to be removed, leaving the duct 18 with the lid 12 replaced in its proper position.

In using the apparatus 10 in the manner which has been described, it can be seen that the lid 12 is maintained in a secure condition at all times and in particular, the operator is not required to grip the lid itself, thus reducing risks of trapped fingers or other injuries, and the movement of the lid 12 is assisted by leverage provided between the grip region 54 and the appropriate axis 24, 28.

Alternative locking mechanism Figs 9 and 10 illustrate part of the apparatus 10, illustrating the incorporation of an 10 optional latch mechanism 86. The latch mechanism 86 comprises a release lever 88 and two latch arms 90, 92. The lever 88 and the arms 90, 92 turn together, around a pivot 94. Each arm 90, 92 is in the form of a hook.

The main limb 40 is provided with a post 96. The collapsible arm 56 is provided with a loop 98. The position of the post 96 is such that when the apparatus 10 is in the folded condition of Fig 9 (corresponding with Fig 1), the latch arm 90 can swing to hook onto the post 96, thereby locking the apparatus 10 in the folded condition by holding the arm 52 close to the main limb 40 and thereby locking the collapsible arm 56 in the collapsed condition. The latch arm 90 can be released from the post 96 by using the release lever 88. This frees the arm 52 to rise.

The collapsible arm 56 straightens as the arm 52 rises and eventually reaches its over-centre position (Fig 10, corresponding with Fig 5). The position of the loop 98 is such that in this condition, the latch arm 92 can hook onto the loop 98. This locks the arm 52 against collapse, thereby locking the arm 52 in the raised position relative to the main limb 40.

The latch mechanism 86 is therefore able to lock the collapsible arm 56 either in the collapsed condition or the fully extended condition, thereby locking relative positions of the jaws 30, 32.

Other latch mechanisms could be used. Separate latch mechanisms could be provided for locking the arm 52 in the folded condition and in the raised condition.

The latch arrangements may serve to lock the arm 52 in the folded condition or in the raised condition, but not both.

Concluding comments Many variations and modifications can be made to the apparatus described above, without departing from the scope of the present invention. In the examples described, the base member 26 has been provided with a foot portion 66, which is expected to be particularly desirable when dealing with the lids of ducts 18. In other examples, such as paving slabs, the base member 26 may be provided with ground-engaging wheels (indicated by broken lines 84, only in Fig 8) so that once the base member 26 has moved under the raised first edge region 14, the first edge region 14 can be lowered until the wheels 84 are engaging with the ground. The second edge region 16 can then be raised in a manner similar to that described above, leaving the whole weight of the apparatus 10 and the planar member 12 supported on the wheels 84, allowing the paving slab to be moved conveniently to a new location.

Many variations in the shapes, sizes and relative shapes and sizes of the various components can be chosen, according to the intended use of the apparatus, the manufacturing techniques used for the apparatus 10 and other factors relating to the use and manufacture of the apparatus.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

CLAIMS1. Lifting apparatus for use in lifting a generally planar member which has first and second generally opposed edge regions; the apparatus comprising: a releasable arrangement operable, in use, to hold the planar member; a first pivot portion providing, in use, a first generally horizontal pivot axis for turning the apparatus to raise a first edge region of the planar member; and a base member which, in use, can move to a position below the raised first edge region to provide a supportive base for the apparatus, wherein the base member serves to support the first edge region in the raised position and provides, in use, a second generally horizontal pivot axis for raising the second edge region while the first edge region remains raised.

LD 15
2. Apparatus according to claim 1, further comprising a lock arrangement I operable to lock the releasable arrangement.
3. Apparatus according to claim 1 or 2, wherein the releasable arrangement is operable to clamp the planar member between first and second jaws.
4. Apparatus according to claim 3, wherein the first and second jaws are pivotally connected to turn relative to one another between a clamp position and a release position.
5. Apparatus according to claim 3 or 4 and claim 2, wherein the lock arrangement includes a collapsible arm connected between the jaws, to control the relative positions of the jaws.
6. Apparatus according to claim 5, wherein the collapsible arm has an over-centre action to lock the jaws against a planar member.
7. Apparatus according to claim 5 or 6, there being a latch mechanism operable to lock the collapsible arm, thereby locking the relative positions of the jaws.
8. Apparatus according to any of claims 3 to 7, wherein the first jaw provides the first pivot portion.
9. Apparatus according to any of claims 3 to 8, wherein the first pivot portion is an extremity of the first jaw, on which the lifting apparatus can rock.
10. Apparatus according to any of claims 3 to 9, wherein one of the jaws has an extension which serves, in use, as a handle for rocking the apparatus about the horizontal pivot axes.
11. Apparatus according to any preceding claim, wherein the base member is movable relative to the rest of the apparatus by pivoting.
12. Apparatus according to any preceding claim, wherein when the base member up has moved below the raised first edge, in use, the rest of the apparatus may be pivotable on the base member to raise the second edge region.
13. Apparatus according to claim 11 or 12, wherein the second pivot axis for co raising the second edge is the same as the pivot axis for moving the base member zo below the raised first edge region.
14. Apparatus according to any preceding claim, wherein the base member has a foot which supports the apparatus when the base member is below the raised first edge.
15. Apparatus according to claim 14, wherein the foot is shaped to fit over a structure below the raised first edge, to retain the apparatus in position on the structure.
16. Apparatus according to any preceding claim, wherein the base member has at least one wheel which is positioned to engage the ground when the base member is under the raised first edge portion, to allow the apparatus and the planar member to be moved while supported on the wheel or wheels.
17. Apparatus according to any preceding claim, wherein the position of the second pivot axis relative to the base member allows the combined centre of gravity of the apparatus and the planar member to be moved past the second pivot axis.
18. Lifting apparatus substantially as described above, with reference to the accompanying drawings.
19. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.