GB2313353A

GB2313353A - A hoist transportable by towing

Info

Publication number: GB2313353A
Application number: GB9709420A
Authority: GB
Inventors: David Albert Wheelwright
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-05-22
Filing date: 1997-05-10
Publication date: 1997-11-26
Anticipated expiration: 2017-05-10
Also published as: GB9709420D0; GB2313353B; GB9610713D0

Abstract

A portable hoist comprises a substantially L-shaped frame (1) to which is attached at least one wheel (21) and a hitch (23) by means of which the hoist can be transported by towing in a first position thereof. A jib (6) is pivotally attached to a first arm (5) of the Lshaped frame (1) and a hydraulic ram (11) is provided for rotating the jib (6). The hoist is adapted to be tipped out of its first, towing position into a second position suitable for lifting loads. In this second position a second arm (4) of the frame lies adjacent to the ground and the jib (6) can be rotated to extend outwardly of the first arm (5) and above the second arm (4) which thereby forms a load bearing support for the hoist when in use. Preferably, a pair of wheels (21) is attached to the frame (1) and the wheels (21) are arranged only to be in contact with the ground in the first, towing position of the hoist. Conveniently, the hoist can be adapted by the provision of an adaptor to provide a fork-lift hoisting capability.

Description

A HOIST The present invention relates to a portable hoist and in particular to a hoist which can be transported by towing.

The hoist of the present invention has been designed with a view to providing a hoist which is of simple yet strong construction, which can be easily manoeuvred when in use, and which can be readily transported by towing.

According to the present invention there is provided a portable hoist comprising a substantially L-shaped frame to which is attached at least one wheel and a hitch by means of which the hoist can be transported by towing in a first position thereof, a jib pivotally attached to a first arm of the Lshaped frame, and means for rotating the jib, the hoist being adapted to be tipped out of said first position into a second position suitable for lifting loads wherein a second arm of the frame lies adjacent to the ground and the jib can be rotated to extend outwardly of the first arm and above the second arm which thereby forms a load bearing support for the hoist when in use.

Preferably, a pair of wheels is attached to the frame, one at each side thereof, which wheels are arranged only to be in contact with the ground in the first position of the hoist.

Preferably also, the pair of wheels are attached to the frame adjacent to the angle of the L-shaped frame and the hitch is attached at the end of the first arm of the frame.

Preferably also, the frame is fabricated from a pair of tubes which have each been bent into an L-shape and which are fastened together by a tie located adjacent to the angle of the L-shaped frame.

Preferably also, the frame is provided with castors which support the frame in the second position to permit it to be maneouvred into a position for use.

Preferably also, the end of the second arm of the frame means is provided with support wheels which together with the castors support the frame in its second position.

Preferably also, the jib comprises a boom in which slides an extension arm.

Advantageously, the hoist comprises an adaptor enabling it to provide a fork-lift hoisting capability.

Preferably, the adaptor comprises a pair of fork-lift prongs, a plate to the one side of which the prongs are attached projecting normally therefrom and which can be rotatably secured to the jib, and at least one support arm which is rotatably attached at one end to the plate and at its other end to the first arm of the frame.

Preferably also, the support arm and the first arm of the hoist define a parallelogram whereby on rotation of the jib, the plate is raised but remains in a substantially vertical plane and thereby retains the prongs in a substantially horizontal position.

Conveniently, the means for rotating the jib comprises a hydraulic pump means.

The present invention will now be described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a perspective side view of a hoist according to the invention in a first position wherein it can be transported by towing; Fig. 2 is a view in the direction of arrow A in Fig.l; Fig. 3 is a perspective view of the hoist in a second position with the jib thereof in a raised position ready for use; Fig. 4 is a view in the direction of arrow B in Fig.

2; and Fig. 5 is a view similar to Fig. 3 but with the jib in a lowered position and showing the hoist modified to provide a fork-lift hoisting capability.

The hoist comprises a substantially L-shaped frame 1 which is fabricated from a pair of tubes 2, typically steel tubes, which have each been bent into an L-shape.

The tubes 2 are similarly oriented and are connected together at the angle of the L-shape by a tie 3 comprising a box fabrication to which other parts of the hoist are also connected, as is described below. Along one arm 4 of the frame 1, the tubes 2 extend parallel to one another but are spaced apart to form load-bearing members for the hoist. Along the other arm 5 of the frame 1 the tubes 2, are curved inwardly along approximately half their length to lie contiguous with one another at the end of the arm 5.

A jib 6 is pivotally attached between the contiguous tubes 2 at the end of the arm 5 of the frame 1. The jib 6 comprises a main boom 7 in which slides an extension arm 8 that can be fixed relative to the arm by means of a pin or bolt 9. At the end of the extension arm 8 is formed an integral hook 10.

The jib 6 is preferably rotated and locked in position by means of a hydraulic ram 11 or other hydraulic pump means. The cylinder 12 of the ram 11 is attached to the tie 3 and its movable piston 13 is attached to the boom 7. Preferably, the ram 11 is attached to both the tie 3 and the boom 7 by means of bolts 14 which engage through holes 15 in the tie 3 and the boom 7. By providing a series of holes 15 in both the tie 3 and the boom 7, the position of the ram 11 can be adjusted so that the degree to which the jib 6 can be rotated relative to the frame 1 can be varied. The hoist can therefore be adapted for use according to the requirements of the job in hand.

A hydraulic pump 16 for the ram 11 is also attached to the tie 3 along with a pressure gauge 17, which is calibrated to indicate the load being supported by the jib 6 when in use. The hydraulic lines linking the pump 16 with the ram 11 can be located within the tubes 2 of the frame, which protects them from injury. Operation of the pump 16 is controlled by a lever 18 which can be rotated within the confines of a C-shaped stop bar 19 fastened to the tubes 2 forming the arm 5 of the frame 1. The stop bar 19 also serves as a guard for the lever 18 and a grip to assist in manoeuvring the hoist into the correct position for use.

At each end of the tie 3 is attached a stub axle 20 for a tyred wheel 21 with a mudguard 22 for use in transporting the hoist. In this regard, a towing hitch 23 is attached to the boom 7 of the jib 6 adjacent to its pivot point. The hitch 23 is positioned so that it is only when the jib is in its lowermost position with the ram 11 fully withdrawn that it is orientated suitable for use.

In a first position of the hoist, as shown in Figs 1 and 2, wherein the arm 6 of the frame lies adjacent to the ground, the hoist is supported by the wheels 21 can can be attached to a vehicle via the hitch 23 for transportation by towing.

In order to use the hoist for lifting loads, however, it is necessary to tip it through 90" into a second position, as shown in Figs 3 and 4. This is accomplished by lifting the end of the arm 5 of the frame 1 by means of a handle 24 which is attached to one of the tubes 2 adjacent the hitch 23. As the arm 5 of the hoist rises and the arm 4 lowers, a pair of castor wheels 25 which are attached to the tie 3 each adjacent to one the wheels 21 respectively come into contact with the ground. Further rotation of the hoist, conveniently using both the handle 24 and a footrest 27 located adjacent the pump 16, then causes the wheels 21 to be lifted off the ground and the ends of the tubes 2 forming the arm 4 of the frame to contact the ground. In this regard, the ends of these tubes 2 are provided with small solid, support wheels 26 so that the hoist is supported in its second position by the castor wheels 25 and these support wheels 26.

The hoist can now be maneouvred into a position for use using the the stop bar 19. The jib 6 can be raised via the ram 11 and the boom 7 of the jib 6 extended in length by means of the arm 8 so that the hook can be connected to a load. The jib 6 can then be further raised or lowered, as appropriate and the position of the hoist adjusted. It will be appreciated that in this position whilst carrying a load, the jib 6 extends above the tubes 2 forming the arm 4 of the frame 1 which thereby bear the load.

One major advantage of the L-shape of the frame of the hoist in this second position is that it can be maneouvred very close to the load to be lifted. The tubes 2 forming the arm 4 of the hoist can be placed on either side of the load or, for example, beneath a vehicle or other carrier which is supporting the load prior to lifting. After the load has been lifted by the jib 6, the hoist is stable and, in view of the weight being carried, unable to tip easily out of position. The hoist can then be maneouvred on the wheels 25, 26 using the stop bar 19.

When the load has been removed from the hook 10, the hoist can be readily tipped back into the first position for transportation. First the arm 8 must be retracted and locked into the boom 7 and the jib 6 rotated into its lowest position. By using the handle 24 and the footrest 27, the arm 4 of the frame 1 can be raised until the tyred wheels 21 contact the ground. The hoist can then be wheeled to a towing vehicle and attached thereto via the hitch 23.

In a modification as shown in Fig. 5, the hoist is adapted to provide a fork-lift hoisting capability by the addition of a pair of horizontal prongs 28 which form part of a bolt-on adaptor means 29. These means 29 comprise the prongs 28, a plate 30, which in use is intended to be retained in a vertical plane, as shown in Fig. 5, and at least one but preferably a pair of support arms 31. The hoist can otherwise remain as previously described although preferably in the second, lifting position shown in Fig. 5, the arms 5 are substantially vertically orientated rather than over-centre as shown in Figs. 1 to 4. In addition, the hook 10 may be dispensed with and the extension arm 8 adapted to be secured to the plate 30 by defining at least one bolt hole.

The prongs 28 are rigidly secured to the lower edge of one side of the plate 30 in order to project outwardly on each side of the hoist parallel to the arms 4 and substantially normal to the plate 30. As is conventional, the prongs 28 may be spaced apart a predetermined distance which is typically that suitable for lifting standard size pallets but this is not a requirement of the means 29.

At the centre of its upper edge and on the opposite side to that of the prongs 28 is located a pair of pierced lugs 32. These lugs 32 are used to bolt or pin the plate 30 to one of the bolt holes defined by the extension arm 8 in such a manner that as the jib 6 rotates, the plate swivels around the bolt or pin to remain always in a substantially vertical plane.

Similarly, at the lower corners of the plate 30 and again on the opposite side to the prongs 28 are pierced lugs 33. These lugs 33 are respectively rotatably secured by bolts or pins to one end of one of the support arms 31.

The other ends of the support arms 31 are respectively rotatably secured to one of the arms 5 of the hoist. It will be appreciated that the extension arm 8 should project from the boom 7 so that the total length of the boom 7 and arm 8 is similar to the length of the arms 31.

In addition, the position of securement of the arms 31 to the arms 5 will depend on the height of the plate 30, which should be sufficient to permit the prongs 28 to lie very close the the ground in the lowermost position of the boom 7. In any event, as shown in Fig.5, all these components define a parallelogram whereby raising the boom 7 by means of the ram 11, the plate 30 is raised but remains in a substantially vertical plane so that the prongs 28 are raised and remain substantially horizontal.

It will be appreciated that the maximum height to which the prongs 28 may be raised is equal to the height of the arms 5. The prongs 28 cannot be raised above the level of the hoist, as would be the case in a conventional fork-lift truck lifting arrangement, but the adaptor means 29 can be employed when convenient for the load in question. These means 29 can be attached to the hoist when required and removed and carried separately when the hoist is being towed.

Claims

1. A portable hoist comprising a substantially L-shaped frame to which is attached at least one wheel and a hitch by means of which the hoist can be transported by towing in a first position thereof, a jib pivotally attached to a first arm of the Lshaped frame, and means for rotating the jib, the hoist being adapted to be tipped out of said first position into a second position suitable for lifting loads wherein a second arm of the frame lies adjacent to the ground and the jib can be rotated to extend outwardly of the first arm and above the second arm which thereby forms a load bearing support for the hoist when in use.

2. A hoist as claimed in Claim 1, wherein a pair of wheels is attached to the frame, one at each side thereof, which wheels are arranged only to be in contact with the ground in the first position of the hoist.

3. A hoist as claimed in Claim 2, wherein the pair of wheels are attached to the frame adjacent to the angle of the L-shaped frame and the hitch is attached at the end of the first arm of the frame.

4. A hoist as claimed in any one of Claims 1 to 3, wherein the frame is fabricated from a pair of tubes which have each been bent into an L-shape and which are fastened together by a tie located adjacent to the angle of the Lshaped frame.

5. A hoist as claimed in any one of Claims 1 to 4, wherein the frame is provided with castors which support the frame in the second position to permit it to be maneouvred into a position for use.

6. A hoist as claimed in Claim 5, wherein the end of the second arm of the frame means is provided with support wheels which together with the castors support the frame in its second position.

7. A hoist as claimed in any one of Claims 1 to 6, wherein the jib comprises a boom in which slides an extension arm.

8. A hoist as claimed in any one of Claims 1 to 7, comprising an adaptor enabling the hoist to provide a fork-lift hoisting capability.

9. A hoist as claimed in Claim 8, wherein the adaptor comprises a pair of fork-lift prongs, a plate to the one side of which the prongs are attached projecting normally therefrom and which can be rotatably secured to the jib, and at least one support arm which is rotatably attached at one end to the plate and at its other end to the first arm of the frame.

10. A hoist as claimed in Claim 9, wherein the jib, the plate, the support arm and the first arm of the hoist define a parallelogram whereby on rotation of the jib, the plate is raised but remains in a substantially vertical plane and thereby retains the prongs in a substantially horizontal position.

11. A hoist as claimed in claimed in Claim 9 or Claim 10, wherein a pair of support arms are provided which are respectively attached to opposite edges of the plate and to each side of the first arm of the frame.

12. A hoist as claimed in any one of Claims 1 to 11, wherein the means for rotating the jib comprises a hydraulic pump means.

13. A portable hoist substantially as described herein with reference to Figs. 1 to 4 or Fig. 5 of the accompanying drawings.