GB2203405A - Lifting device for hollow articles - Google Patents

Abstract

A device for engaging an article to be lifted, eg a gulley (11), comprises a rigid elongate member (12) having a recess (19) at one end of a first part (15) thereof and facing axially of the member, a second abutment part (14) with a rounded end (21) at the other end of the member (12), and attachment means (18) for connecting the member (12) to a lifting chain (13) from which the device may be suspended. The member (12) is adjustable in length by the part (14) being slidable or screw threaded into part (15). The attachment between the chain and member (12) may be adjustable by forming a cross-piece (23) at the end of the chain which can enter a slot (28) in the member and then be turned through 90 DEG so that ridges (25a, 26a) engage in a selected one of a plurality of U-shaped grooves (29). <IMAGE>

Description

LIFTING TACKLE The present invention relates generally to lifting tackle, and particularly to a device for use in lifting hollow and/or fragile objects.

When manoeuvring heavy objects into position it is very often necessary to use a crane or other lifting mechanism capable of exerting the required lifting force. The function of a crane can often be performed by a mechanical excavator since this has an articulated arm capable of being.raised and lowered, with the articulation allowing the free end of the arm to perform substantially vertical movements rather than arcuate movements, should this be desired.

It is known to provide a crane of the type having a jib and a suspended flexible chain or other linear lifting member with gripping members capable of engaging externally the perimeter of an object to be lifted. One such gripping assembly comprises a parallelogram linkage the lower limbs of which are extended as jaws, and the upper articulation point of which is used as a suspension point connecting the assembly to the chain. The gripping assembly is placed over an object to be lifted and, upon the application of upwardly directed tension, the parallelogram tends to close causing the jaws to approach one another until they grip the article to be lifted. This works well on regularly shaped articles, such as stacks of blocks or bricks mounted on pallets, because the centre of gravity of the stack can be anticipated when positioning the gripper.There are articles, however, the complexity of the shape of which or the fragile nature of which makes it difficult if not impossible to use such conventional grippers. It is also possible to encounter situations when the article or object to be lifted also has to be lowered into a narrow space, and the external projection of grippers could prevent the object from entering the space into which it is to be lowered.

Further, clamping grippers cannot be used on fragile articles if the force exerted upon clamping is likely to be sufficiently great as to fracture the article in the act of lifting.

The present invention seeks, therefore, to provide means for replacing known lifting tackle assemblies with a simple engagement member which can be used on a wide range of objects to be lifted, either directly or by means of suitable modifications.

One job which is frequently encountered during the laying of drains is that of the provision of large gulleys or sediment traps which comprise substantially cup-shape bodies made from baked clay or concrete, and having a spigot projecting from one curved wall of the body. These are lowered into preliminarily formed holes which, in order to economise on their production, are made no larger than is absolutely necessary to receive the gulley. Further, because of the fragile nature of the large cup-shape body, and because it is too heavy to lift by hand, it is often raised using a chain by means of a mechanical excavator.Chains fitted around the outside of the body, hqwever, frequently slip, or if securely fitted, result in the body being lifted at an inconvenient angle to be lowered directly into the hole, necessitating the use of many levers and additional labourers to position the gulley over the hole before it can be lowered, and to orientate it properly to fit the hole.

The present invention seeks to provide a lifting device by means of which such an inconveniently shaped object, as well as other hollow and/or fragile objects, can be lifted easily.

According to one aspect of the present invention, therefore, a device for engaging an object to be lifted comprises a rigid elongate member having a recess or cavity at one end thereof facing axially of the member, an abutment portion at the other end of the member and attachment means for connecting the member to a lifting chain or other such suspension element from which the device can be suspended. By positioning the attachment means between the ends of the member this can adopt an approximately horizontal or slightly inclined orientation when allowed to hang freely.In these circumstances, the device can be lowered into an open or hollow object to be lifted, and by positioning the recess or cavity against any convenient inward projection and applying tension to the suspension member, the other end can be swung into contact with a facing interior wall whereupon further tension on the lifting or suspension member causes frictional engagement providing the length of the lifting device is greater than the maximum dimension across the interior space of the object to be lifted. Then, the assembly can be raised easily with the object being held from the inside by the engagement of the two opposite ends of the lifting device.

Providing the lifting device is longer than the diameter or appropriate internal dimension of the object being lifted there is no risk of it falling because the engagement does not rely on friction, but rather is a type of form engagement. In order to ensure that the object suspended by the lifting device adopts a convenient orientation it is preferable that the attachment means are adjustable in position along the'length of the member whereby to adjust the point of application of the lifting force by the suspension member.

Adjustment may be provided in any one of a number of ways. For example adjustment may be provided by means of a plurality of preliminarily formed interconnection means to a selected one of which the associated connector at the end of the suspension member may be fitted. This may be achieved, for example, by means of a plurality of loops or holes formed along the length of the lifting device into which a ring or pin can be fitted to interconnect the lifting device with the suspension member. Alternatively, the adjustment may be achieved by means of an elongate slot in the said engagement member and clamping means for fixing the connector at the end of the suspension member in any selected position along the slot.Another appropriate arrangement for effecting rapid adjustment would be by providing a T-shape slot, that is one having undercut sides, with a plurality of asperities or parallel corrugations in the form of triangular section grooves transversely of the length of the slot. An appropriate connection member comprises a T-shape element the cross-bar of which has a triangular cross-section matching that of the grooves in the underside of the slot so that, when the chain is slack, the connector can be displaced along the length of the slot, but when the chain is tight the ridge on the underside of the cross-bar of the T-shape connector member engages in a selected groove to prevent displacement of the connector longitudinally of the slot even if an inclined orientation of the lifting member is adopted, which would result in a component of force along the length of the slot.

Instead of a single ridge, of course, the T-shape member may be provided with a plurality of such ridges.

In order to be usable on a wide range of different objects the engagement member may be adjustable in length, such adjustment being achieved by forming the engagement member in two parts which are telescopically slidable with respect to one another and adjustable either in an infinitely variable manner, such as by screw means, or in discrete steps, for example by means of a ribbed or ridged construction similar to that described hereinabove in relation to the adjustment of the connector along the length of the engagement member.

In a preferred embodiment of the invention the recess or cavity at the said one end of the engagement member is a generally V-shape notch or indentation. In other embodiments, however, this recess or cavity may have a different configuration.

One embodiment of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic side view illustrating a lifting member formed in accordance with the principles of the present invention, showing the device in use; and Figure 2 is an enlarged perspective view, partly cut away, showing an alternative embodiment of the invention.

Referring first to Figure 1, a device for lifting heavy hollow fragile objects, such as a gulley 11 is generally indicated with the reference numeral 12. This device comprises a rigid elongate member formed in two parts and suspended from a chain 13. The two parts of the member 12 are identified with the reference numerals 14 and 15, and the part 14 is adjustable longitudinally of the part 15. This is achieved by means of the provision of a plurality of holes 16 in the part 15, which can receive a pin (not shown) passing through a selected hole 16 and a single hole (not shown) with which the member 14 is provided. The member 15 is formed as a generally box-sectibn element with the member 14 a similar, but smaller section, slidable within it.

The chain 13 is secured to the part 15 by means of a pivotal connection generally indicated with the reference numeral 18 which is off-set towards one end of the first part 15, identified with the reference numeral 17, remote from the second part 14 and formed with a V-shape notch or recess 19 which, in use of the lifting device, can engage an interior corner such as that presented by the spigot 20 which projects from the cylindrically curved wall of the cup-shape gulley 11.

At the end remote from the V-shape notch 19 the second part 14 of the device 12 is provided with a rounded free end 21. In use of the device the chain 13 is lowered with a device 12 suspended from its lower end until it enters the interior of the gulley 11. The notched end 19 can then be positioned so that it engages a suitable projection such as the corner of the spigot 20, and upon application of a tension to the chain 13 the device 12 is caused to turn about its contact with the corner of the spigot 20 until the nose end 21 of the inner part 14 comes into contact with the facing opposite inner wall of the gulley 11.Further rotation is prevented because the length of the device 12, suitably chosen by adjustment of the inner part 14, is greater than the transverse dimension of the gulley 11 and consequently further tension on the chain 13 results in the gulley 11 being bodily lifted by the engagement of the device 12. In the embodiment of Figure 1 the position of the anchorage of the chain cannot be changed and accordingly if the gulley 11 does not hang entirely conveniently, as illustrated in Figure 1, no adjustment is available.

The embodiment of Figure 2 differs from that of Figure 1 by the provision of such adjustment. In this embodiment the chain 13 has a connector generally indicated 22 in the form of a T-shape body having a transverse cross piece 23 with two limbs 24, 25 projecting in opposite directions from a main body 26 having a loop 27 by which the body is attached to the chain 13.

The two limbs 24, 25 have a generally triangular cross-section with a respective ridge 24a, 25a facing in the direction of the chain 13.

The lifting device 12, like the embodiment of Figure 1 has a box-section and is formed in two parts, namely a telescopically outer part 15 and a telescopically inner part 14. The upper wall of the outer part 15 is formed with a longitudinal elongate slot 28 and is formed on the inner surface of the wall having the slot 28 with a plurality of transverse, V-section grooves 29. The width of the slot 28 is slightly greater than the width of the limbs 24, 25 of the cross-piece 23 of the T-shape connector body 22. By turning this so that the limbs 24, 25 extend parallel to the slot 28, therefore, the body 22 can be introduced into the interior of the outer part 15, whereupon it can be turned through 900 so that the limbs 24, 25 then lie orthogonally of the length of the slot 28.

The ridge 24a, 25a can then be engaged with one of the triangularsection grooves 29 to define a non-slip engagement between the connector 22 and the lifting device 12. In use the device of Figure 2 is positioned in the same way as that of Figure 1, with the exception that there is the additional option of adjusting the point at which the force is applied by the chain 13 to the device 12 so that if the gulley 11 does not hang in a convenient orientation, for example if it is tilted to one side or the other, it is possible by lowering it and allowing the chain a little slack, to re-position the connector 22 to one direction or the other along the slot 28 so that the gulley 11 will hang straight when lifted.

When the gulley has been lowered into the preliminarily formed hole it is a simple matter to depress the nose end 14 of the device allowing the notched end 17 to be released from its engagement with the corner of the spigot 20 whereupon the device as a whole can be extracted leaving the gulley in position.

Claims (10)

1. A device for engaging an object to be lifted, comprising a rigid elongate member having a recess or cavity at one end thereof, facing axially of the member, an abutment portion at the other end of the member and attachment means for connecting the member to a lifting chain or other such suspension element from which the device can be suspended.

2. A device as claimed in Claim 1, in which the said attachment means are adjustable i position along the length of the member whereby to adjust the point of application cf the lifting force by the suspension member.

3. A device as claimed in Claim 2, in which adjustment is provided by means of t plurality of preliminarily formed interconnection means to a selected one of which an associated connector at the end of the suspension member can be fitted.

4. A device as claimed in Claim 2, or Claim 3, in which the adjustment s achieved by means of an elongate slot in the said engagement member and clamping means for fixing a connector at the end of the suspension member at any selected position along the slot.

5. A device as claimed in any preceding Claim, in which the engagement member is adjustable in length.

6. A device as claimed in Claim 5, in which the length adjustment is achieved by forming the engagement member in two parts which are telescopically slidable with respect to one another.

7. A device as claimed in Claim 5 or Claim 6, in which the length adjustment is continuously or infinitely variable such as by screw means.

8. A device as claimed in Claim 5 or Claim 6, in which the length adjustment can be made in discrete steps.

9. A device as claimed in any preceding Claim, in which the recess or cavity at the said one end of the member is a generally V-shape notch or indentation.

10. A device for engaging an object to be lifted, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.