GB2061223A - Load lifting apparatus - Google Patents

Abstract

The invention relates to load lifting apparatus, in particular for use in building or building repair work. The invention provides apparatus comprising a ladder 10 and a separable hoist structure 9. The hoist structure 9 has a track 17 along which a load carrier 14 is moved by a pulley and cable system. The load carrier 14 is guided along the track 17 by means of mutually opposed pairs of rollers 22 which grip the track 17. The hoist structure is attached to the ladder 10, which is an extensible ladder consisting of two portions 11 and 12, by upper and lower brackets 18 and 16. The pulley and cable system is powered by a detachable power unit 20. The hoist structure 9 is wholly supported by the ladder 10 and thus can be made of a light metal which allows it to be light and easily portable. Therefore, hoist structures weighing as little as 30kg or less may be made which could be easily carried around a building site by a single worker. <IMAGE>

Description

SPECIFICATION Load-lifting apparatus The present invention relates to load-lifting apparatus and is particularly applicable to apparatus for use in building and/or building repair work.

A common problem in the building trade, which for the purposes of the Specification will be regarded as including building repair, is the effort involved in lifting and lowering bricks, roofing tiles, mortar and other heavy materials. When the carrying of such materials, for example roofing tiles, is done by hand, the main problems to be encountered are that only a few tiles can be carried at one time, thus slowing the rate of working, and that the fatigue produced by strenuous effort can lead to dangerous accidents. At the same time, anyone climbing a ladder carrying building materials has only one hand free to support himself, with an increased safety hazard.

Buildings' elevators of different types are known, to overcome the above problems. For example, there is known a buildings' elevator having a boom, the angle of inclination of which is adjustable. The carrying portion consists of an endless, moving flat belt, having metal cleats at intervals along the belt to support the material being carried. The boom is supported by a base support which also supports the engine which drives the flat belt. The total weight of the machine is in excess of 800 kgs.

A telescopic elevator is known, which has an extensible rail system upon which a carriage runs.

The rails are lightweight, being made of aluminium, and the carriage is fitted with nylon rollers which run on top of the rails. The carriage is winched up and down the rails. The rail system is supported by a base support which also carried the engine which drives the winch rope. The total weight of such an elevator is in excess of 400 kgs.

The above-mentioned elevators have the disadvantage of being bulky and heavy. They have to be towed to the site and manoeuvring of such elevators into position can be difficult, particularly when there is little room for manoeuvre. Accessibility to some parts of a house may be limited and in some cases the size of the elevator may mean that parts of a house are completely inaccessible to the elevator. Another disadvantage is that the size of the base support may in some cases be large enough to involve damage to gardens and property.

There is also known, for example, from British Patent Specification No. 1 119 460, hoists in the form of ladders provided with tracks along which a load carrying carriage may move. However, such proposals still have the disadvantage of being heavy due to the need of structural strength to supportthe carriage and the load being carried.

The present invention seeks to mitigate at least some of the above disadvantages.

According to the present invention there is provided a load-lifting apparatus comprising a ladder and a separable hoist structure, the hoist structure comprising a track along which a hopper is guided, a pulley and cable system for winching the hopper up the track, and means for attaching the hoist structure to the ladder, wherein the hoist structure is light and portable and is strengthened by attachment to the ladder.

In the description and claims, the expression "light and portable" is taken to mean sufficiently light to be carried by a building site worker. Since the hoist structure does not provide its own strength, but obtains its structural strength from the ladder, it may be made of a very light metal, such as aluminium or light steel. Preferably, the hoist structure may weigh at little as 30 kg or less.

Apparatus embodying the invention may be easily set up on site, simply by using a ladder which is on site in any case and attaching the hoist structure to the ladder. In this way, any part of the house which is accessible to a ladder is also accessible to an apparatus embodying the invention. The invention also has the advantage that whereas many known building and elevators have to be towed to a building site, the hoist structure of the invention may be carried to the site, for example, on a roof rack of a small car or a van.

The track of the hoist structure may be telescopically extensible so that the length of the hoist structure may be adjusted to be attached to any length of ladder.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevational view of one embodiment of the present invention; Figure 2 is a side elevational view of a hoist structure; and Figure 3 is a section through the track and part of the hopper in one embodiment of the invention.

In Figure 1, a load-lifting apparatus comprises a hoist structure generally designated 9 and a telescopically extensible ladder generally designated 10.

The ladder 10 has two portions 11 and 12, and is shown resting against a building 13. The hoist structure 9 comprises a track 17 along which a hooper 14 is guided. The track 17 is connected to the top rung of the ladder 10 by means of a bracket 18 and rests against the ladder, the bottom of the track 17 being bolted around the bottom rung of the ladder 10 easing a further bracket 16. In this way, the hoist structure is wholly supported by the ladder 10.

In Figure 1, the track 17 is not extensible, but consists of a plurality of portions 19 which are bolted together. The length of the track 17 can be increased or decreased by the inclusion or removal of one of the portions 19. By using a plurality of small track portions 19, a track of any desired fixed length can be assembled quickly and easily on the building site.

The hopper 14 is winched up and down the track 17 by means of a pulley and cable system, the cable being indicated by reference numeral 15 in the drawings. The pulley and cable system is powered by a detachable power unit 20, but it is possible that in some circumstances the pulley and cable system could be operated manually.

The hopper 14 is guided along the track 17 by means of pairs of rollers 22, each pair of rollers being mutually opposed in such a manner that the track 17 is between each pair. The positioning of the rollers is described below with reference to Figure 3.

The brackets 16 and 18 serve to attach the hoist structure 9 securely to the ladder 10 and the hoist structure is wholly supported by the ladder. Since the hoist structure 9 is supported in this way, it can be made from a light metal such as light steel or aluminium and is therefore easily portable. Hoist structures of less than 30 kg may be designed. This compared favourably with the weight of prior art apparatus. A particular advantage of the lightness and portability of a hoist structure is that no special machinery or support means os required, since the supportforthe loads is provided, not by the hoist structure, but by the ladder which is an article which would be on a building site in any case. Any conventional ladder could be fitted with the hoist structure quickly and easily.

In Figure 2, there is shown a telescopic extensible hoist structure separate from the ladder. The hoist structure, generally designated at 21 comprises mutually slidable track portions 24 and 26 which allow the height of the hoist structure to be adjusted to suit a particular need. A hopper 14 is winched up and down the track 24,26 by means of a pulley and cable system comprising a cable 28 which runs over a pulley 29, the cable being winched by a detachable power unit 30 which is here shown as attached in the region at the top of the hoist structure. This serves to reduce loss of energy due to friction between the cable and the pulley. The hoist structure 21 is provided with brackets 32 and 34 which enables it to be attached to a ladder.The tips of the uprights may project, for example beyond the top of a wall orthe edge of a roof, to allow the power unit 30 to rest on the wall or roof.

As shown in Figure 3, the hopper 14 is unable to move smoothly from one portions of the track to the next by means of tapering of one of the tracks. In Figure 3, a pair of mutually opposed rollers 22 of the hopper 14 are at the transistion points between two portions 54 and 56 of an extensible track. The rollers are preferably made of nylon or rubber and are of large diameter compared with the thickness of the track. The outer portion 56 of the track is tapered as shown to allow the rollers run smoothly between the two portions 54 and 56.

Any of the above described hoist structures may be provided with a roof extension which in use rests on the roof of a building. This will facilitate the carrying of tiles, for example, up the roof.

The hopper may be designed in a number of different way to suit different materials to be carried.

Claims (12)

1. A load-lifting apparatus comprising a ladder and a separable hoist structure, the hoist structure comprising a track along which a hopper is guided, a pulley and cable system for winching the hopper up the track, and means for attaching the hoist structure to the ladder, wherein the hoist structure is light and portable and is strengthened by attachment to the ladder.

2. An apparatus as claimed in Claim 1 wherein the track of the hoist structure is made of aluminium.

3. An apparatus as claimed in Claim 1 or Claim 2 wherein the hoist structure weighs less than 30 kg.

4. An apparatus as claimed in any preceding claim wherein the track is telescopically extendable.

5. An apparatus as claimed in Claim 4wherein one end of each telescopic portion is tapered to allow the hopper to pass smoothly up and down the track.

6. An apparatus as claimed in any preceding claim wherein the hopper is guided along the track by means of rollers.

7. An apparatus as claimed in Claim 6 wherein the rollers are arranged in pairs which are mutually opposed so as to retain the track between each pair of rollers.

8. An apparatus as claimed in Claim 6 or Claim 7 wherein the rollers are made of nylon.

9. An apparatus as claimed in any of Claims 6 to 8 wherein the diameter of the rollers is large compared with the thickness of the track.

10. An apparatus as claimed in any preceding claim wherein the means for attaching the hoist structure to the ladder comprises a bracket at one end of the track for attachment to the top rung of the ladder and a second bracket at the other end of the track for attachment to the bottom rung of the ladder.

11. An apparatus as claimed in any preceding claim in which the pulley and cable system is powered by a detachable power unit.

12. A load-lifting apparatus substantially as herein before described with reference to and as illustrated in the accompanying drawing.