WO1990001015A1

WO1990001015A1 - A hoist

Info

Publication number: WO1990001015A1
Application number: PCT/AU1989/000304
Authority: WO
Inventors: Brian Ross Klopper
Original assignee: Brian Ross Klopper
Priority date: 1988-07-21
Filing date: 1989-07-21
Publication date: 1990-02-08

Abstract

The invention relates to a hoist having upper and lower hollow members (14, 12) which are arranged so that the lower members (12) remain stationary whilst the upper members (14) move upwardly. A deck (32) is attached to the upper member and is arranged to hoist a load. The movement of the upper members (14) is under the influence of pressurised fluid such as a mains water supply fed through conduits (24) into the lower members (12).

Description

TITLE A HOIST DESCRIPTION The present invention relates to a hoist for lifting an object.

FIELD OF THE INVENTION In the context of the present invention the term hoist (and hoisted) is chosen to mean raised and/or lowered. In particular, the hoist of the present invention is intended for use at a building site. Previously, hoists of the prior art have relied upon a motor or an on site source of hydraulic pressure to effect lifting of a load. The motor has typically been of the electric or petrol driven type while a source of hydraulic pressure has typically been a compressor of known type.

Generally, these prior art devices have been dependant on the reliability of the motor or compressor.

SUMMARY OF THE INVENTION The present invention provides a hoist utilising a remote supply of hydraulic pressure, conveniently a mains water supply.

In accordance with one aspect of the present invention there is provided a hoist comprising at least one first, lower hollow upright member sealingly inserted into a corresponding second, upright upper hollow member, the or each first hollow member being arranged to communicate with a source of hydraulic pressure, a deck attached to the or each second upper hollow member and' disposed to receive a load to be hoisted, the or each secor hollow member being arranged to be moved reciprocably relative to the or each corresponding first hollow member by hydraulic pressure, fro the source thereof so as to hoist the deck. Preferably, the first and the second hollow members are tubes in fluid tight engagement.

Preferably, said source of hydraulic pressure is a pressurised mains water supply, more preferably comprising an inlet and an outlet valve. In accordance with a further aspect of the present inventio there is provided a method of hoisting a load which comprises placing the load on a deck of a hoist in front according to the present invention with the or each second upright hollow member in a position below its uppermost position, connecting each pair of upper and lower upright hollow members to a supply of pressurised mains water so as to supply water into the pair of members and cause the uppe hollow member to move upwardly away from the ground, ceasin to supply pressurised mains water when the deck has reached a desired height, removing the load from the deck, and allowing fluid to be released from the pair of upper and lower upright hollow members so that the upper member and the deck can fall under the influence of gravity back to a desired lower portion.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a side view of a hoist in accordance with the present invention in a lowered condition; Figure 2 is a side view similar to Figure 1 from the opposite side with the hoist in a raised position; Figure 3 is a schematic front vertical sectional view of a modified hoist of the present invention in a raised position;^~and

Figure 4 is a plan view of the hoist of Figures 1 and 2.

DESCRIPTION OF THE INVENTION Shown in Figures 1 to 4 is a hoist 10 comprising a plurality of first, lower upright hollow members in the form of tubes 12. Each tube 12 has an open end 13 inserted into a corresponding second, upper upright hollow member in the form of a tube 14.

Each tube 14 has an open lower end 16 and a closed upper end 18 and is capable of telescoping movement particularly as can be seen in Figure 2.

At the upper end 18 there is a bleed valve 20 to allow the escape of air in the embodiment of Figures 1 and 2. In the embodiment of Figure 3, the upper ends 18 have a balance arm 21 with a central bleed valve 21a. Each tube 12 is sealingly engaged with the corresponding tube 14.

Preferably, the tubes 14 are provided with an internal liner (not shown) having a smooth surface to contact the tubes 12. Such a liner may typically be plastics material pipes located internally of the tubes 14.

Further, the tubes 12 communicate with each other adjacent their lower ends via a plurality of conduits 24. The conduits 24 may also form a base to support the tubes 12. The conduits 24 are attached to and communicate with a conduit 26 having an inlet valve 28 and an outlet valve 30. Attached to the tubes 14 at or adjacent the open ends 16. is a deck 32 typically comprising a plurality of timber beams. A plurality of bracing members in the form of sloping bars 34 extend between pairs of tubes 14 and are each attached at one end to a tube 14 near the end 18 thereof and at another end to a point intermediate of the ends 16 and 18 as can be seen in Figure 3. A plurality of additional bracing members in the form of horizontal bars 36 also extend between pairs of tubes 14 and are each attached to the tubes 14 near the ends 18 or at a lower level intermediate of the ends 16 and 18 as can be seen in Figure 3. As may be seen in Figure 3, there is also provided a plurality of flexible bracing members in the form of chains 38 which are attached at one end to the deck 32 and at another end to a conduit 24. When the hoist 10 is in the raised position shown in Figure 3, the chains 38 are taut and thereby brace the hoist 10. The chains 38 may be adjustable by known means (not shown).

The tubes 14 may have a plurality of holes adjacent the open ends 16.

In use, the hoist 10 is disposed upon a surface, typically the ground 100, such that the conduits 24 are adjacent the ground 100. A supply of hydraulic pressure (not shown) is connected to the inlet valve 28. Such a supply may be a mains pressure water supply and the hydraulic fluid could be water. The bleed valves 20 or 21a are then opened and the valve 28 is opened to admit a supply of fluid. The fluid displaces any air trapped in the tubes 12 and 14. The bleed valves 20 or 21a are closed once all the air has been bled from the tubes 12 and 14 usually indicated by the egress of fluid from the bleed valves 20 or 21a. The inlet valve 28 is then closed to prevent raising of the deck 32, to be described hereinafter.

A load 102 is then placed on the deck 32 and the inlet valve 28 is opened. Hydraulic pressure acts on the ends 18 of the tubes 14 and forces the tubes 12 and 14 to telescope apart whilst the sealing engagement inhibits fluid escaping and consequent loss of pressure. The tubes 14 thus lift the deck 32 away from the ground 100. When the deck 32 has reached a desired height, the valve 28 is closed and hydraulic pressure can no longer act on the ends 18 of the tubes 14 to further raise the deck 32. The deck 32 is thus held at this height and the load 102 may be removed. If for some reason the valve 28 cannot be closed, the tubes 14 could be raised to such a height that the holes in the tubes 14 would be above the tubes 12. Hydraulic fluid would then be able to escape through the holes 39 and the tubes 14 would no longer be able to be raised. This is a safety feature to prevent the tubes 14 from departing from telescopic engagement with the tubes 12 and thereby collapsing the hoist 10.

It is preferred that the chains 38 be taut and thereby brace the tubes 12 and 14 as the load 102 is removed and/or placed onto the deck 32, The deck 32 is then lowered by opening the outlet valve 30.

Hydraulic fluid escapes through the valve 30 and the tubes

14 fall under the influence of gravity so that each pair of tubes 12 and 14 telescope together thus lowering the deck 32. When the deck 32 has reached a desired height, the valve 30 is closed and hydraulic fluid can no longer escape. The sealing engagement of the tubes 12 and 14 inhibit any loss of hydraulic fluid and the deck 32 is held at the desired height. The present invention provides a hoist having a simple construction and able to utilise a mains pressure water supply for operation. Further, operation of the hoist only requires th'e use of two valves.

By virtue of the present invention expensive and complicated hydraulic means such as hydraulic compressors or motors are not required. Instead a readily available source of hydraulic fluid is used.

It is envisaged that the valves 28 and 30 could be located on or about the deck 32 to allow an operator to also ride on the deck 32. Preferably, the outlet valve 30 is arranged so that the hoist cannot fall quickly or suddenly when the valve 30* is opened.

The balance arm 21 interconnects two tubes 14 so that the fluid pressure therein is equalised. Modifications and variations such as would be apparent to a skilled addressee are deemed within the scope of the present invention.

Claims

1. A hoist characterised in that it comprises at least one first, lower hollow upright member sealingly inserted into a corresponding second, upright upper hollow member, the or each first hollow member communicating with a source of hydraulic pressure, a deck attached to the or each second, upper hollow member and disposed to receive a load to be hoisted, the or each second hollow member being arranged to be moved reciprocably relative to the or each corresponding first, lower hollow member by hydraulic pressure from the source thereof so as to hoist the deck.

2. A hoist according to Claim 1, characterised in that it comprises at least two of the first, lower hollow upright members each sealingly inserted into corresponding second, upright upper hollow members, the first and second upright members being spaced apart and having the deck disposed between them.

3. A hoist according to Claim 2, characterised in that it comprises four of the first, lower hollow upright members each sealingly inserted into corresponding second, upright upper hollow members and arranged at respective corners of a general rectangular shape with the deck disposed between them.

4. A hoist according to any one of the preceding Claims, characterised in that the or each first lower hollow upright member is connected to a conduit means arranged to be connected via an inlet valve to a mains water supply.

5. A hoist according to Claim A , characterised in that there is also provided an outlet valve arranged to release liquid from the first and second hollow members.

6. A hoist according to any one of the preceding Claims, characterised in that the second upright upper hollow members are braced together adjacent their upper ends.

7. A hoist according to any one of the preceding Claims, characterised in that the deck is inter connected to the first lower hollow upright members by means of flexible bracing members.

8. A hoist according to any one of the preceding Claims, characterised in that the second upright hollow members hav holes such that when the hoist is in elevated position excess fluid may be released through the holes to prevent excessive raising of the hoist.

9. A hoist according to any one of the preceding Claims, characterised in that the or each second, open hollow membe has an upper closed end and a lower open end disposed about a first lower hollow member.

10. A hoist according to any one of the preceding Claims, in which the or each second upright hollow member has a bleed valve located adjacent its upper end.

11. A method of hoisting a load which comprises placing th load on a deck of a hoist as claimed in any one of the preceding Claims with the or each second upright hollow member in a position below its uppermost position, connecting each pair of upper and lower upright hollow members to a supply of pressurised mains water so as to supply water into the pair of members and cause the upper hollow member to move upwardly away from the ground, ceasin to supply pressurised mains water when the deck has reached a desired height, removing the load from the deck, and allowing fluid to be released from the pair of upper and, lower upright hollow members so that the upper member and the deck can fall under the influence of gravity back to a desired lower portion.