AU2003254411B2 - A lifting or transporting means using a reciprocating jack - Google Patents

Description

WO 2004/020766 PCTIAU2003!001112 1 A LIFTING OR TRANSPORTING MEANS USING A RECIPROCATING JACK This invention relates to a lifting or transporting means that uses a reciprocating jack and in particular to an arrangement which enables the lifting or transporting means to move in a particular direction utilising the reciprocating motion of the jack.

The invention will find numerous applications both lifting in vertical or inclined directions, lowering in vertical or inclined directions or moving loads in horizontal directions.

BACKGROUND OF THE INVENTION One particular application is in relation to the building industry for moving protective screens in relation to the building structure. Primarily, screens such as safety screens need to be raised as the building increases in height during the construction process. Patent Application No PCT/AU02/00506 by the current applicant describes a means of lifting safety screens with respect to a building. The disclosure within the specification of PCT/AU02/00506 specification is, by reference, hereby incorporated to this specification.

The lifting mechanism described in the earlier Patent Application makes use of a pair of horizontal beams with an interconnecting screw thread. The screen, which is secured to one of the horizontal beams is raised through rotation of the screw thread which raises the other beam so that the two beams are brought closer together. The screen is then itself supported with respect to the building so as to enable the supporting beam to be moved away from the beam by rotating the screw threads in the opposite direction. The process of lifting the frame can then recommence once the beams are again separated.

WO 2004/020766 PCT/AU2003/001112 2 The lifting means subject of the present application is an alternate arrangement to that described in the earlier Patent Specification. It provides a useful choice which will be advantageous in some applications by comparison to the lifting means described in the earlier specification.

SUMMARY OF THE INVENTION In one aspect, the invention is a lifting means for lifting a frame with respect to a fixed support including: a frame; a reciprocating jack that expands and contracts and which is secured at one end to said fixed support; a first bracket on said jack that slidably engages said frame and that moves due to expansion or contraction of said jack; a second bracket fixed with respect to said fixed support that slidably engages said frame; and latch means on each said first and second bracket engagable with said frame that allows movement of the frame in one direction with respect to the bracket but engages with the frame to prevent its movement in the other direction so that as the jack expands, the latch means on the first bracket engages the frame to move it, and wherein the frame slides through the second bracket until the jack contracts, where upon the latch means on the second bracket engages and holds the frame while the first bracket slides with respect to the frame.

As described above, the invention provides a means for the jack lifting or pushing the frame in one direction as it expands and the frame being held in that position while the jack contracts. When it fully contracts, then it can recommence the lifting and moving operation.

WO 2004/020766 PCT/AU2003/001112 3 As indicated above, the invention can be used to lower a frame where upon the latch means on the lower bracket is disengaged to allow lowering the frame during contraction of the jacking means. The lower bracket latch can be re-engaged to allow the jack to expand.

It will also be apparent that the invention can work for lifting or lowering at inclined angles and will also function in a horizontal direction working against a load applied to the frame.

Preferably, the lifting or moving means uses a pair of reciprocating jacks although a single jack will also satisfactorily operate. In this case, the frame may be no more than an elongate beam.

The reciprocating jack may comprise a conventional hydraulic or screw thread operated jacking system. However, it may also comprise other means which provide a force on expansion and/or contraction. For example, it may comprise a rack and pinion operated mechanism which is electrically driven.

The brackets may comprise any convenient means which enables them to be attached to and slide with respect to the frame. Preferably, the bracket may comprise an assembly which opens so that it can be directly attached to the frame upon closing.

In such an example, one side of the bracket may be hinged so that the bracket can be attached to the frame and held in place by closing the hinged side in a locked position.

The latch means may be any arrangement that allows the bracket to freely slide along the frame in one direction but that engages with the frame so as to prevent it moving from the opposite direction. This may comprise a spring-loaded pin mounted within the bracket that locates in apertures within the frame. The apertures may have WO 2004/020766 PCT/AU2003/001112 4 sloping ramped surfaces in one direction that enable the pin to be compressed against the spring force to gradually cause it to retract. The other end of the aperture may have an abutment surface that engages against the pin to thereby prevent movement of the frame in that direction.

Alternatively, the frame may comprise a pair of posts that are held apart and joined by a plurality of joiners spaced in intervals along the length of the posts. The bracket comprises a pair of channels that engage either side of one of the posts and the latch means is a bar hinged to one of the plates and extends between the posts to abut against the top of the plate on the opposite side. As the bracket moves downwardly, a joiner abuts against the bar and deflects it upwardly. As the joiner passes the bar, it drops into a horizontal position. If the bracket is moved in the opposite direction, then the joiner abuts against the upper surface of the bar and prevents further movement of the bracket. This latch means enables the bracket to move freely in one direction along the frame but is prevented from doing so in the opposite diredction.

It will be readily understood by a person skilled in the art that there will be other designs of latch means which will meet the requirements of the invention.

Preferably, in relation to a vertical lift, the lower end of the jack is secured to a fixed support. In the case of lifting building safety screens, this support would be one of the preformed floors and supports would be located at and extend over the edge of the building. Additional guiding supports may be provided at upper or lower levels to ensure stability of the frame. The guiding supports may also be provided with brackets and associated latch means which allow movement of the frame in one direction but prevent movement in the opposite direction.

In order to fully understand the invention, the preferred embodiment will now be described. However, it will be realised that the invention is not to be restricted to the WO 2004/020766 PCT/AU2003/001112 embodiments described. Other improvements and variations of the invention will be readily apparent to a skilled person.

BRIEF DESCRIPTION OF THE DRAWINGS The embodiment is illustrated in the accompanying drawings in which: Figure 1 shows a safety screen to be lifted by the lifting means; Figure 2 shows a side view of a lifting means installed on a building site and used for lifting safety screens in relation to the edge of the building; Figure 3 shows a side view of a lifting means used for raising safety screens in relation to the building that shows a variation of supporting arrangements by comparison to what was used in the arrangement shown in Figure 1; and Figure 4 shows a plan view of a lifting means showing support beams that are used to support the frame.

DETAILED DESCRIPTION Referring to Figure 1 the lifting means 10 comprises a frame 11, a reciprocating jack which in this embodiment comprises a hydraulic cylinder 12 and brackets 13 attached at either end of the hydraulic cylinder 12 that are inturn secured slidably with respect to elements of the frame 11.

In this embodiment, the lifting means 10 is designed to lift a safety screen 14 in relation to the outside of a building that is being constructed. Figure 1 shows completed floors 15 of the building and the safety screen 14 being raised in relation to floors 15 and to a yet to be completed floor 16. As described in the previous Patent Application referred to above, the safety screen 14 screens the external surface of the building while awaiting final fixing of windows or external walls. This principally prevents objects accidentally falling from the building site and also provides personal safety to the workers.

WO 2004/020766 PCT/AU2003/001112 6 In addition, the safety screen 14 extends above the upper most completed floor 15 to also provide a safe working environment while form-work is being fixed on the upper most floor to create the next floor 16. The screen 14 can be easily raised as required, to enable work to then commence on floor 16 for construction of the next floor.

The frame 11 is supported by beams 17 that are secured to the floor 15. The brackets 13 have a downwardly extending pin (not drawn) that locates within an aperture in the end of the beams 17. This enables rotation of the bracket 13 with respect of the beams 17 to enable the beams 17 to be fixed at an angle with respect of the floor and for the bracket 13 to rotate with respect of the beam 17 to adapt to any minor position variations of the frame 11.

The hydraulic cylinder 12 is attached to the bracket 13 which is secured to beam 17.

A bracket 13 is attached to the upper end of the hydraulic cylinder 12.

In order to provide additional support further beams 18 may be secured at floors above or below the location of the hydraulic cylinder 12. In Figure 1, the additional support beams 18 are located above the hydraulic cylinder 12. It also includes an angle support 19 and a vertical support 20. A bracket 21 is secured to the beam 18 in the same way that bracket 13 is secured to beam 17. The upper ends of the angled and vertical supports 19 and 20 are also secured to a bracket 21. Brackets 21 attach to the frame and function the same way as brackets 13.

As seen in Figure 3, each lifting means 10 uses two hydraulic cylinders 12 and therefore has two sets of beams 17 and 18 and corresponding supports 19 and Although two hydraulic cylinders 12 are shown in the current embodiment, three or more hydraulic cylinders could also be used. In the case of two or more hydraulic cylinders 12, the important requirement is to achieve a reasonably equal rate of WO 2004/020766 PCT/AU2003/001112 7 expansion of each cylinder 12. This is easily achieved by a person skilled in hydraulics. In addition, systems may be provided where a single hydraulic cylinder 12 is used. In this case, additional support beams 18 may be spaced laterally of the hydraulic cylinder 12 either at the same level as the hydraulic cylinder 12 or above or below it.

The frame 11 comprises a bracket post 24 and a screen post 25. As seen in Figure 3, the bracket and screen post 24 and 25 are spaced apart from one another and are connected by plurality of joiners 26 that are evenly spaced along the length of the bracket and screen post 24 and 25. The joiners 26 are narrower than the bracket post 24. The result is a series of elongate slots formed between the posts 24 and 25 and the joiners 26. The function of these elongate slots in relation to the bracket and latch means will be described further below.

The brackets 13 and 21 comprise a pair of side plates 28 that each have flanges 29 on their forward edges that partly locate in front of each of the bracket posts 24. One or each of the side plates 28 are either hinged or can be separated to enable the brackets 13 and 21 to be secured to a bracket post 24. Once located in place, the brackets 13 and 21 can slide in relation to the bracket post 24 but obviously act to retain the frame 11 with respect to the brackets 13 and 21.

Each bracket 13 and 21 are provided with latch means that is designed to enable movement of the frame 11 in only one direction with respect to each of the brackets 13 and 21. The latch means (not drawn) comprises a bar which is hinged to the upper edge of one of the side plates 28. The bar extends across the bracket so that it rests on the upper surface of the opposite side plate 28. The bar is positioned so that it extends through the elongate apertures formed by the spacing of the bracket and screen post 24 and 25 and the joiners 26.

WO 2004/020766 PCT/AU2003/001112 8 In use, when the frame 11 is moving upwardly, a joiner 26 will eventually abut against the underneath surface of the bar. Continued upward movement of the frame 11 will result in the bar hinging upwardly and allowing the joiner 26 to pass where upon the bar will again hinge downwardly to rest on the upper surface of the adjacent side plate 28. The bar will prevent downward movement of the frame 11 when the joiner abuts against the upper surface of the bar.

In operation, as the hydraulic cylinder 12 is expanding, the latch means on the bracket 13 on the upper end of the hydraulic cylinder 12 will abut against the joiner 26 and therefore lift the frame 11. Upward movement of the frame will not be prevented by the remaining bracket 13 and the other brackets 21. The bar will hinge upwardly to allow the joiners 26 to pass as required.

At the maximum extent of expansion of the hydraulic cylinder 12, the joiners 26 are spaced such that a joiner 26 will have only just have passed the latch means on the bracket 13 of the lower end of the hydraulic cylinder and the remaining brackets 21.

Accordingly, contraction of the hydraulic cylinder 12 will result in the frame being held as the joiners 26 abut against the upper surface of the bar on the brackets 21 and bracket 13 on the lower end of the hydraulic cylinder 12. The latch means on the bracket 13 on the upper end of the hydraulic cylinder 12 will operate to allow the bracket 13 to move downwardly with respect to the frame 11 until it reaches its lower most position. Again, this may be designed so that it is conveniently placed in relation to a joiner 26 so that upon commencement of the expansion of the hydraulic cylinder 12, the bar on the bracket 13 on the upper end of the hydraulic cylinder 12 will again engage a joiner 26 to resume lifting the frame 11.

In this way, the frame 11 can be conveniently lifted in relation to the support beams 17 and 18. Obviously, a relatively short stroke hydraulic cylinder can be effectively used to lift the frame.

WO 2004/020766 PCT/AU2003/001112 9 Once the lower edge of the screen 14 reaches its upper most position in relation to the support beam 17, then it is a simple process to re-position the hydraulic cylinder 12 to an upper level. As seen in Figure 2, the hydraulic cylinder 12 can be disconnected from the bracket 13 of its lower end. The upper bracket 13 is disconnected from the bracket post 24. The lower bracket 13 and the lower bracket 21 continue to support the frame 11 while the hydraulic cylinder 12 is disconnected. The support 19 and together with the upper bracket 21 are removed and the hydraulic cylinder and its upper bracket 13 above are put in place. At this stage, the upper floor 16 is likely to be completed where upon the supports 19 and 20 can be located on this floor together with a support beam 18. In this way, the safety screen 14 can continue to advance upwardly in relation to the building as it is being constructed.

As can be seen from the above description, the invention provides a simple and convenient means of lifting a safety screen 14 with respect to a building. However, as mentioned above, the invention is not to be limited to this particular application.

It may also find applications in relation to lowering loads, or alternatively moving loads in a horizontal direction.

Claims (9)

1. A lifting means for lifting a frame with respect to a fixed support including: a frame; a reciprocating jack that expands and contracts and which is secured at one end to said fixed support; a first bracket on said jack that slidably engages said frame and that moves due to expansion or contraction of said jack; a second bracket fixed with respect to said fixed support that slidably engages said frame; and latch means on each said first and second bracket engagable with said frame that allows movement of the frame in one direction with respect to the bracket but engages with the frame to prevent its movement in the other direction so that as the jack expands, the latch means on the first bracket engages the frame to move it, and wherein the frame slides through the second bracket until the jack contracts, where upon the latch means on the second bracket engages and holds the frame while the first bracket slides with respect to the frame.

2. A lifting means according to Claim 1 wherein said lifting means also acts as a lowering means.

3. A lifting means according to either Claim 1 or 2 wherein said frame further comprises a post secured to said frame and where said first and second brackets engage said post.

4. A lifting means according to Claim 3 wherein said post is elongate and extends substantially the full height of said frame.

WO 2004/020766 PCT/AU2003/001112 11 A lifting means according to either Claim 3 or 4 wherein said latching means comprises a restraint between said first and second brackets and said post.

6. A lifting and lowering means for lifting or lowering a frame with respect to a fixed support including: a frame; a reciprocating jack that expands and contracts and which is secured at one end to said fixed support; a bracket located at each end of the jack, said brackets slidably engaging said frame; and latch means on each bracket engagable with the frame that allows movement of the frame in one direction with respect to the bracket but engages with the frame to prevent its movement in the other direction so that as the jack expands, the latch means on the first bracket engages the frame to move it, and wherein the frame slides through the second bracket until the jack contracts, where upon the latch means on the second bracket engages and holds the frame while the first bracket slides with respect to the frame.

7. A lifting means according to any one of the preceding claims further comprising two or more reciprocating jacks.

8. A lifting means according to any one of the preceding claims wherein said reciprocating jacks comprise hydraulic jacks.

9. A lifting means according to any one of the preceding claims wherein said lifting means is used to lift safety screens on a multi-storey building. A lifting means substantially as herein described with reference to the accompanying drawings.