Lifting device

Abstract

 A mobile lifting device comprises a dismantlable frame (10) mounted on wheels (19,19') and supporting an elevated horizontal beam (15) which projects out beyond the perimeter of the frame (10). A load (44) is raised or lowered by means of a chainwinch (30) depending from a trolley (27) running along the projecting part of the beam (15). The support framework (10) is ballasted with any convenient material to counterbalance the load; in a development, one or more containers (36) of water are used as ballast.

Description

[0001] This invention relates to lifting devices.

[0002] It is a frequent requirement in many industries to lift and manipulate heavy or bulky loads, and the prior art provides a variety of solutions.

[0003] In the building industry, loads may be carried up the side of a building by means of a platform travelling up and down within an enclosed, vertical cage, and supported by scaffolding or the like. Where scaffolding is in place on the outside of a building, a pulley wheel may alternatively be attached to an outwardly extending member thereof at a high point, and loads raised or lowered by hauling on a rope passing over the pulley wheel.

[0004] The methods described above suffer from a number of disadvantages.

[0005] Where scaffolding or the like is employed to provide lifting means for moving loads on the outside of a building, it will typically comprise a temporary structure which is fixed in one location, and may be heavy, bulky, expensive and inconvenient to transport. Such lifting means also typically require the operator to manually haul in the load on a swinging rope, or manipulate it in the confined space of a lift, involving an awkward and potentially hazardous operation.

[0006] It is the object of the present invention to provide movable lifting means which is quicker and cheaper to install and operate and safer and easier to use.

[0007] According to the present invention there is provided a movable lifting device composed from a plurality of separate elements which may be readily assembled and disassembled to and from each other, and comprising support means supporting a load suspension member, together with load movement means supported by said load suspension member; and
characterised in that said load suspension member projects outwardly beyond the perimeter of said support means, and by mounting means for mounting a ballast mass on said support means so as to counterbalance a load attached to said load movement means.

[0008] In a development, water containing means may be used as ballast means.

[0009] A specific embodiment of the invention will now be described by way of example and with reference to the accompanying drawings in which:

Figure 1 shows a side elevation of a lifting device without ballast;

Figure 2 shows an end elevation of the lifting device shown in Figure 1, with load movement means shown partly in cross section;

Figure 3 shows a perspective view of a lifting device as shown in Figures 1 and 2 in use on a building;

Figure 4 shows a side elevation of the lifting device shown in Figure 1 with additional ballast support means supporting water retaining means; and

Figure 5 shows a perspective view of water retaining means for use with a lifting device as shown in Figure 1.

[0010] Corresponding parts in each Figure are indicated by the same reference numbers.

[0011] Referring to Figures 1 and 2, a support framework 10 comprises a base 12 and intermediate support members 13, 13', the intermediate support members 13, 13' supporting a load suspension member 15, said load suspension member projecting outwardly beyond the ground area defined by the base 12 to form a load suspension portion 16. The load suspension portion 16 is additionally supported by support arms 17 and a crosspiece 18, which transfer part of the load from the load suspension portion 16 to the intermediate support members 13'.

[0012] The support framework 10 comprises a plurality of rigid, lightweight elements which are conveniently joined to each other and to the load suspension member 15 and other parts by means of readily dismantlable attachment means, such as nuts and bolts. In the embodiment, the lifting device is disassembled into the base 12, the intermediate support members 13, 13', the support arms 17, the crosspiece 18, the load suspension member 15, and a flat platform 20 comprising ballast support means. The base 12 is further disassembled into its component struts 24, 33. In use, the lifting device may be dismantled into component elements small enough to be readily manhandled into position, for example, on the roof of a partially constructed building, where they are reassembled ready for use.

[0013] The base 12 is supported on the ground by wheels 19, 19' and supports ballast support means 20, said ballast support means comprising a flat platform disposed upon the framework of an end portion 21 of the base 12, said end portion 21 being that portion of the base 12 situated furthest away from the load suspension portion 16. The base 12 is further provided with an additional, swivelling wheel 22, located at the midpoint of an end member 24 of the base 12, which wheel 22 may be raised or lowered by rotating a handle 23. In use, the handle 23 is rotated to lower the swivelling wheel 22 into a ground-engaging position, and further rotated to raise the end member 24, raising the wheels 19' clear of the ground. The support framework 10 is then supported by wheels 19 and the swivelling wheel 22, allowing it to be rolled along the ground and steered into any desired position. The swivelling wheel 22 may then be raised by reversing the above described procedure until the support framework 10 is lowered to rest on all four wheels 19, 19'.

[0014] The load suspension portion 16 of the load suspension member 15 provides load suspension surfaces 25, which load suspension surfaces 25 define a substantially horizontal track supporting rollers 26 of load transfer means 27, said rollers being retained in a housing 28 of the load transfer means 27 by axle and bearing means (not shown for simplicity) of known design. The load transfer means 27 is retained by the load suspension portion 16 and able to travel therealong between end stops 31, 32, said end stops being fixed to the load suspension portion 16 such that they respectively abut against the load transfer means 27 at the limits of its travel. The housing 28 is further provided with an attachment point 29, which may be a fixed or swivelling ring, from which a load raising and lowering means is suspended. Said load raising and lowering means is conveniently a chainwinch 30 of known design, said chainwinch comprising a body 40, which body is attached to the attachment point 29; said chainwinch further comprising a loop of chain 41, and a load attachment member 42.

[0015] Referring to Figure 3, showing the lifting device deployed ready for use on the roof 45 of a building, the ballast support means 20 is loaded by the user with conveniently available ballast 43 such that the downward force exerted by the ballast 43 upon the ballast support means 20 is substantially greater than the opposing upward force generated by a working load 44 when said working load 44 is lifted off the ground by the chainwinch 30. The working load 44 is attached to the load attachment member 42, and the chain 41 is hauled by the user, the chainwinch 30 typically multiplying the force exerted by the user to draw the load attachment member 42 towards the body 40, until the working load 44 is raised to the desired height.

[0016] The working load 44 may then be drawn in safely by the user over the edge of the roof 45, the load transfer means 27 travelling along the load suspension portion 16 between the end stops 31, 32. The working load 44 may then be moved across the roof 45 into a desired position by rolling the lifting device along on the wheels 19, 19'; alternatively, greater manoeuvrability may be achieved by deploying the additional wheel 22 using the abovedescribed procedure.

[0017] At least some of the wheels 19, 19' may be provided with braking means (not shown for simplicity) to retain the lifting device in a fixed position during operation.

[0018] Referring to Figures 3 and 4, in a development support framework 10 is provided with additional ballast support means 35, comprising a cradle wherein a plurality of water containers 36 are placed containing water which provides additional or alternative ballast to ballast 43.

[0019] Referring to Figures 3 and 5, in a further development a tank 50 for containing water ballast is provided for use as an alternative or addition to ballast 43. Said tank 50 is adapted to rest upon ballast support means 20, and comprises tank body 51, provided on an upper surface 56 thereof with removable filler cap 52 screwed over filling aperture 53, and further provided adjacent the base 54 thereof with tank emptying valve means 55.

[0020] The tank 50 may conveniently be constructed from plastics material, making it light in weight, although in order to contain a substantial mass of water it will be bulky. Where the lifting device is to be deployed, for example, on the roof 45 of a partially constructed building, the lifting device may therefore first be assembled in the desired position, and then used with little or no ballast to lift the tank 50 into position on the roof 45 of the building.

[0021] To facilitate this procedure, upper surface 56 of the tank 50 is further provided with attachment means 57 to which, in use, the load attachment member 42 may be attached prior to lifting the tank 50 as described above.

[0022] In use, the tank 50 is placed upon the ballast support means 20 and filled with water, for example by means of a hosepipe. In order to provide the user with an accurate indication of the safe working load which may be applied to the lifting device, a level gauge 60 is provided, comprising a transparent plastics tube 61 arranged in a substantially vertical orientation on an outer surface 58 of the tank 50. The tube 61 communicates with the inside of the tank 50 through attachment points 62, 62', respectively adjacent the upper surface 56 and base 54, and contains floating on the water surface within the tube 61 a brightly coloured plastics marker 63. The outer surface 58 is further provided with a scale 64 adjacent the tube 61, said scale being marked in divisions indicating the safe working load of the lifting device. In use, the tank 50 is filled with water until the marker 63 reaches a point on the scale 64 corresponding with the desired working load to be raised by the lifting device.

[0023] The present invention is not limited to the embodiments herein described, and it is to be understood that it may be practised other than as described above, and may take the form of any dismantlable, movable lifting device as disclosed herein for deployment on rooftops, platforms or elsewhere for lifting loads thereto. Other advantages and features of the present invention will become evident to those skilled in the art upon perusal of the description, claims and drawings herewith provided.

Claims

1. A movable lifting device composed from a plurality of separate elements (24, 33, 15, 13, 13', 17, 18, 20, 35) which may be readily assembled and disassembled to and from each other, and comprising support means (10) supporting a load suspension member (15), together with load movement means (27, 30) supported by said load suspension member; and characterised in that said load suspension member projects outwardly beyond the perimeter of said support means, and by mounting means (20, 35) for mounting a ballast mass (43, 36, 50) on said support means so as to counterbalance a load (44) attached to said load movement means.

2. A lifting device as described in Claim 1 wherein said ballast support means comprises a platform (20) upon which a heavy mass of material (43, 50) may be disposed.

3. A lifting device as described in Claim 1 wherein said load movement means may move along said load suspension member between defined limits of travel (31, 32).

4. A lifting device as described in any preceding claim wherein said load movement means includes load raising-and-lowering means (30).

5. A lifting device as described in Claim 1 wherein said support means rests at least partially on a plurality of wheels (19, 19') or the like.

6. A lifting device as described in claim 5 wherein at least some of said wheels are provided with braking means.

7. A lifting device as described in Claim 5 wherein a steerable wheel (22) is provided.

8. A lifting device as described in Claim 7 wherein said steerable wheel is disposed in a triangular relationship with two other wheels (19).

9. A lifting device as described in Claim 1 wherein said lifting device is of lightweight construction.

10. A lifting device as described in Claim 1 wherein said ballast support means support water containing means (36, 50).

11. A lifting device as described in Claim 10, wherein said water containing means are constructed from lightweight material.

12. A lifting device as described in Claim 10 wherein said water containing means (50) is equipped with gauge means (60) indicating the amount of water contained therein.

13. A lifting device as described in Claim 12 wherein scale means (64) is provided adjacent said gauge means, said scale means being marked in divisions indicating the safe working load which may be applied to said load raising and lowering means.

Drawing