GB2279326A

GB2279326A - Paving stone lifter

Info

Publication number: GB2279326A
Application number: GB9412960A
Authority: GB
Inventors: Patrick Joseph Walsh; John Gibbons
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-06-29
Filing date: 1994-06-28
Publication date: 1995-01-04
Also published as: GB9313385D0; GB9412960D0

Abstract

A lifting device comprises a carriage 10 which supports a pair of pivotable arms 16, each of which has an L-shaped engagement portion 18 at its lower end. In use, an object 21 (such as a block) to be lifted is frictionally engaged on its side faces 20 by the engagement portions 18. The weight of the object 21 pulls the arms 16 downwardly and urges these to pivot, thereby urging the portions 18 into even closer engagement with the side faces 20. In this way, the weight of the object 21 itself provides the means whereby it is held securely between the arms 16. Preferably both arms are adjustable in size, suspended by chains 19 and have a remotely released retaining mechanism 22. <IMAGE>

Description

Title: Lifting Device This invention relates to a device for lifting heavy objects.

According to the present invention, there is provided a device for lifting an object having a pair of opposed, outwardly-facing side faces, the device comprising a wheeled carriage, and a pair of arms supported by the carriage for pivotal movement relative to one another about a generally horizontal axis, each arm having at its lower end an engagement portion for frictionally engaging a respective one of said side faces of the object, the object being suspended in use beneath the arms such that its weight pulls downwardly on the latter and thereby urges the engagement portions into closer contact with said side faces.

Advantageously, the distance between the engagement portion and the pivot is adjustable in at least one (and preferably in both) of the arms.

Conveniently, each engagement portion comprises a member of generally L-shaped cross-section.

Desirably, each arm is suspended from the carriage by means of a respective elongate flexible member (such as a chain) attached at or adjacent to its end remote from the engagement portion.

Preferably, the device further comprises a manually graspable handle, which is disposed on a side of the rotation axis of the wheels which is remote from the arms.

Advantageously, the device further comprises a release mechanism which normally retains the arms in a predetermined pivotal position relative to one another but which can be released to permit the arms to engage the object.

Conveniently, the release mechanism comprises a retaining member which is mounted on one of the arms and which is slidable into and out of engagement with an aperture in the other arm.

Desirably, the release mechanism is operable remotely from the arms, preferably by way of an elongate flexible member connected to the retaining member.

The invention will now be further described, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is a perspective view of a lifting device according to the present invention; and Figure 2 is a perspective view showing the lifting device in use.

Referring first to Figure 1, the illustrated lifting device comprises a carriage 10 supported on a pair of wheels 11 which are rotatable about a common axis X. The carriage 10 comprises a pair of box-shaped side frames 12 connected together by a series of cross-members 13. Extending forwardly from the upper parts of the side frames are a pair of spaced arms 14, these arms being connected together at their free ends by means of a crosspiece 15.

Suspended from the carriage 10 are a pair of arms 16 which are connected together for relative pivotal movement about a generally horizontal pivot 17. Each arm 16 has at a lower end thereof an engagement portion 18 in the form of a member of Lshaped cross-section, while its other end is attached to a respective end of the cross-piece 15 by way of a respective length of heavy duty chain 19.

Referring now also to Figure 2, the engagement portions 18 are adapted frictionally to engage respective outwardly-facing side faces 20 of an object 21 to be lifted, such as a block as illustrated. The weight of the object 21 pulls down on the arms 16 and thereby urges these about the pivot 17 to urge the engagement portions 18 into even closer contact with the side faces 20. Thus, the weight of the object itself provides a means whereby it is held securely between the arms 16.

In order that different sizes of objects can be accommodated, each arm 16 is made adjustable in length, i.e. the distance between the engagement portion 18 and the pivot 17 can be varied.

The device also includes a release mechanism 22 for holding the arms 16 in a predetermined pivotal position while not in use.

The mechanism 22 comprises a retaining element in the form of a bolt 23 which is slidably housed in a housing 24 on one of the arms 16, and which is movable into and out of engagement with an aperture 25 in a plate 26 secured to the other arm 16. When the two arms 16 are both disposed generally horizontally, the bolt 23 is aligned with the aperture 25 and can be slid into engagement with the latter. The arms are thereby held in these positions, enabling the device to be manoeuvred into position to lift an object. When the engagement portions 18 have been generally aligned with the side faces 20 of the object 21, the bolt 23 can be retracted from the aperture 25 by pulling on a chain 27, thereby allowing the arms 16 to pivot under gravity and bring the engagement portions 18 into contact with the object.

For strengthening purposes, a pair of gussets 28 are provided respectively between the arms 14 and the side frames 12.

Reference numeral 29 denotes a manually graspable handle which extends from the carriage on the opposite side of the wheel axis X to the arms 16, and which enables the device to be manipulated by an operator 30. The chain 27 extends to a position adjacent to the handle 29, in order that the release mechanism 22 can be operated remotely by the operator.

The device described above can be used for lifting and manipulating heavy objects of a variety of different kinds, and is particularly applicable to paving slabs. By using the device, it is possible for paving slabs to be lifted, positioned and laid by one person only.

Claims

1. A device for lifting an object having a pair of opposed, outwardly-facing sides, the device comprising a wheeled carriage and a pair of arms supported by the carriage for pivotal movement relative to one another about a generally horizontal axis, each arm having at its lower end an engagement portion for frictionally engaging a respective one of said side faces of the object, the object being suspended in use beneath the arms such that its weight pulls downwardly on the latter and thereby urges the engagement portions into closer contact with said side faces.

2. A device as claimed in claim 1, wherein the distance between the engagement portion and the pivot is adjustable in at least one of the arms.

3. A device as claimed in claim 2, wherein the distance between the engagement portion and the pivot is adjustable in both of the arms.

4. A device as claimed in claim 1, 2 or 3, wherein each engagement portion comprises a member of generally L-shaped cross-section.

5. A device as claimed in any preceding claim, wherein each arm is suspended from the carriage by means of a respective elongate flexible member attached at or adjacent to its end remote from the engagement portion.

6. A device as claimed in any preceding claim, further comprising a manually graspable handle, which is disposed on a side of the rotation axis of the wheels which is remote from the arms.

7. A device as claimed in any preceding claim, further comprising a release mechanism which normally retains the arms in a predetermined pivotal position relative to one another but which can be released to permit the arms to engage the object.

8. A device as claimed in claim 7, wherein the release mechanism is operable remotely from the arms.

9. A device as claimed in claim 7 or 8, wherein the release mechanism comprises a retaining member which is mounted on one of the arms and which is slidable into and out of engagement with an aperture in the other arm.

10. A device as claimed in claim 9, wherein the release mechanism is operable remotely from the arms by way of an elongate flexible member connected to the retaining member.

11. A lifting device substantially as hereinbefore described with reference to the accompanying drawing.