LIFTING EQUIPMENT
This invention relates to lifting equipment, and in particular to equipment and its method of use for lifting heavy plant and the like to elevated positions on or in buildings.
An outdoor air conditioning unit is one item of heavy equipment that is often required to be lifted into an elevated position onto wall brackets on the side of a building. Conventionally, such items of heavy equipment are lifted into position using mechanical hoists or towers. Hoists require sufficient space to enable them to be moved into a suitable position for lifting, and towers require sufficient space for their erection. Both hoists and towers require level ground in that space for safe use of the hoist or tower. Furthermore, towers take an appreciable length of time to erect and dismantle. To overcome these problems, others have proposed to use a powered hoist that is fitted to the wall mounting brackets on which the air conditioning unit is to be mounted. The hoist cable is attached to the air conditioning unit, which is raised into position and secured to the wall mounting brackets. The hoist cable is then detached from the air conditioning unit and the hoist removed from the mounting brackets. However, the use of such a hoist involves the lifting of the relatively heavy hoist into position and attaching it to the wall mounting brackets by a person on a ladder. Such an operation is not without its difficulties and risks for the person concerned. In addition, the wall mounting brackets required in order to use such a hoist, steel u-shaped construction channels being used, must be significantly longer than those required for mounting the air conditioning unit only. Such struts are relatively cumbersome, time consuming to fit, are prone to rusting over time and, in extending beyond the air conditioning unit, are unsightly.
It is an object of the present invention to provide lifting equipment and a method of use that overcomes to a significant extent the disadvantages of the known equipment and their methods of use.
The invention provides lifting equipment comprising: a frame adapted to be attached to an elevated surface, a hoist having a hoist cable and attachment means for attachment of a load, the frame being adapted to receive the hoist cable, whereby operation of the hoist to retract the cable causes the hoist and any load attached thereto to be raised towards the frame.
Cable includes rope, wire, chain, band, belt, strap or the like. The frame and the hoist cable may have co-operating connection means whereby a free end of the cable may be connected to the frame. The connection means of the cable may comprise a hook adapted to connect with a connection member of the frame. The frame connection member may be a support link.
The frame may comprise an upright support member and a gibbet member attached to an upper part of the support member. The frame may also comprise bracing means, which may comprise a pair of bracing struts connected to the support member and the gibbet member. The bracing struts may be connected to the support member by a removable pin, whereby the frame may be folded for transportation and storage. The bracing struts may be connected to each other by a bearing plate. Preferably, the frame is of aluminium.
The load attachment means may comprise ratchet straps. The hoist may be electrically driven, and the lifting equipment may have a controller opera le to control operation of the hoist. The controller may be connected to the hoist by means of an electrical cable, or may control operation of the hoist remotely, e.g. by an infrared or radio signal or the like. As a further alternative, the hoist may be hand operated or be adapted to be operated by a battery driven drill.
The invention also comprises a method of lifting a load comprising attaching a frame to an elevated surface, attaching a hoist to a load, connecting a cable of the hoist to the frame and operating the hoist to retract the cable to lift the hoist and load towards the frame.
The method may comprise detaching the hoist from the load after lifting and operating the hoist to deploy the cable and lower the hoist from the frame. The method may comprise detaching the cable from the frame after lowering the hoist.
The method may comprise assembling the frame prior to attaching it to the elevated surface, and may comprise detaching the frame from the elevated surface after detaching the cable from the frame. The method may also comprise folding the frame after detaching it from the elevated surface.
The invention will now be described with reference to the accompanying drawings in which: Fig. 1 is a side view of the lifting equipment ready for lifting, Fig. 2 is a side view of the equipment of Fig. 1 after lifting the hoist and load, and Fig. 3 is a view of the frame in the folded configuration.
Referring now to Fig. 1, there is shown lifting equipment 10 for lifting an air conditioning unit 11. Although the equipment 10 is described in relation to the lifting of an air conditioning unit 11, it could be used for lifting other heavy items of equipment to an elevated position adjacent a wall 12 or other elevated surface. To mount the air conditioning unit 11 on the wall 12, a
conventional a/c unit bracket 13 of channel section is secured to the wall 12. The lifting equipment 10 comprises a frame 14 having an upright support member 15 and a gibbet member 16 attached to angle brackets 17 welded to the upper part of the support member 15. The frame 14 also has a pair of bracing struts 18 connected to the support member 15 and the gibbet member 16 to form the rigid triangular frame 14. The bracing struts 18 are welded to a bearing plate 18a, which in use bears on the wall 12. The bearing plate 18a restrains the bracing struts 18 behind the support member 15 to which they are connected by a removable pin 19. The gibbet member 16 is connected to the brackets 17 and the bracing struts 18 by releasable or removable pins 20. By this means, on removal of the pin 19 and release or removal of the pins 20, the frame 14 may be folded for transportation and storage as shown in Fig. 3. The pins 19, 20 may be bolts if preferred. Preferably, the frame 14 is of aluminium so as to be of light weight for ease of transportation and carrying up a ladder for positioning on the wall 12 or other elevated surface. A hook connection 21 support link is mounted on the gibbet member 16.
After transporting the frame 14 to the site in the form shown in Fig. 3, the frame 14 is assembled to the form shown in Fig. 1 and the pins 19, 20 tightened to render the frame 14 rigid. The lower end of the support member 15 is located centrally of the a/c unit bracket 13 to extend vertically upwardly therefrom. The brackets 17, and hence the frame 14, is then secured to the wall 12 by means of screws and plugs 22. If the standard u-shaped construction channel is used to support the a/c unit bracket 13 without any horizontal cross member, then the frame 14 may be secured laterally by a further screw and plug 22 placed through a hole provided in the bearing plate 18a.
A hoist 23 is secured by means of ratchet straps 24 to the air conditioning unit 11. Preferably the surfaces of the a/c unit 11 are protected by means of padding or the like (not shown). The hoist cable 26 is withdrawn from the hoist 23 and a connection hook 25 at the free end of the cable 26 is connected to the hook connection 21 on the gibbet member 16. The hoist 23 is connected to an electrical supply 27 using a lead 28 that is long enough to allow for the raising of the hoist 23. A remote controller 29 sends an infrared or radio signal 30 to a receiver on the hoist 23 to operate the hoist 23. Operation of the hoist 23 causes the hoist cable 26 to be retracted, thereby lifting the hoist 23 and the a/c unit 11 from the position on the ground shown in Fig. 1. The a/c unit 11 is lifted towards the gibbet member 16 to the position shown in Fig. 2. Other forms of signal 30 may be used, or the controller 29 may be connected to the hoist 23 by means of a sufficiently long electrical cable if preferred. As a further alternative, the hoist 23 may be hand operated or be adapted to be operated by a battery driven drill.
When the a/c unit 11 is slightly higher than the desired position, the hoist 23 is stopped. The support bracket outrigger legs 31 (shown in dashed lines in Fig. 2) are mounted on the a/c unit bracket 13 and the hoist 23 is again operated to lower the a/c unit 11 on to the support bracket outrigger legs 31 and a/c unit bracket 13. When the a/c unit 11 is securely in position on the bracket outrigger legs 31 and a/c unit bracket 13, the hoist 23 is detached from the a/c unit 11 by releasing the ratchet straps 24. The hoist 23 is again operated to lower itself to the ground, whereupon the connection hook 25 of the hoist cable 26 is removed from the hook connection 21 on the gibbet member 16. The frame 14 can then be removed from the wall 12, the pin 19 removed and pins 20 released or removed to allow folding of the frame 14 to the substantially plane configuration shown in Fig. 3. The folded frame 14 can be placed in a bag or other container and transported, for example in the boot of a car, to another location for subsequent use.
The plugs 22, possibly with dummy screws therein, may be left in position in the wall 12 so that the frame 14 may be re-attached for removal of the a/c unit 11 for maintenance or replacement purposes. In the event that a part of the a/c unit 11, for example the compressor, requires removal for maintenance or replacement, the hook 25 of hoist 23 may be attached to the hook connection 21. After removal of an end plate 32 from the gibbet member 16, the hoist 23 may be raised up to the gibbet member 16 and slid over the end of the gibbet member 16 to be supported thereby. For safety, the end plate 32 should then be replaced to prevent the hoist 23 from sliding off the gibbet member 16. The hook 25 may be released from the hook connection 21 and attached to the standard lifting eye on the compressor or other part, which may then be detached from the a/c unit 11 and lowered to the ground. The repaired or replacement compressor is later lifted back into position, the hoist 23 lowered and the hook 25 removed.
By means of the invention, lifting equipment is provided that requires only the relatively light frame to be carried manually up and down a ladder. Lifting of a relatively heavy hoist is largely avoided. No unsightly or rusting members remain in place after installation of the a/c unit. The operator can position him or herself remote from the suspended a/c unit during installation, thereby reducing the risk of accidents and injury. The lifting equipment is more readily handled and transported from location to location than is the case with known lifting equipment.