BACKGROUND OF THE INVENTION Existing elevators typically require the construction of a robust well which in addition to the weight of the cage is capable of carrying the hoisting apparatus located on top.

Accordingly elevator installations are expensive and the well structure has to be put in place at the time of building construction. Therefore lower cost residential housing has generally not benefited from this convenience.

SUMMARY OF THE INVENTION It is an object of this invention to ameliorate the aforementioned disadvantages and accordingly an elevator is disclosed for conveying passengers or goods between floors of a building, said elevator including a well and a cage movable vertically therein on roller means engaging in corner rails of said well, lifting means for said cage acting from the base of said well whereby the weight of said cage is carried at said base and said well being constructed substantially from non load-bearing components.

Preferably said well is constructed from panels of sheet metal fixed one upon another in a stacked configuration between said corner rails.

It is further preferred that said lifting means comprise hydraulic ram (s) acting on said cage from the base of said well.

BRIEF DESCRIPTION OF THE DRAWINGS One currently preferred form of this invention will now be described with reference to the attached drawings in which: Figure 1 is a schematic perspective view of the base of an elevator well according to this concept, Figure 2 is an exploded view of part of the well structure of figure 1, and Figures 3 and 4 are perspective views of parts of the elevator cage and well showing the corner roller arms, and Figure 5 is a schematic plan view of the roller arm and corner rail of figure 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to figures 1 and 2 the elevator well may be constructed from sheet metal panels 1 of preferably 1.5 mm thickness which bolt between vertical corner rails 2. A rectangular structure is thus built up according to the number of panels used which extends from the ground to the top story of a building (not shown). The well structure comprises side walls 3, a back wall 4 and an open front 5 for entrance though doors to a passenger cage (not shown).

Although for simplicity of illustration only two sets of vertically stacked panels are shown the well in practice would be built to any required height by extending the length of the corner rails and fitting additional panels.

In accordance with this invention a novel fastening system is proposed for assembling the panels and corner rails. The abutting edge flanges 6,7 of the panels and rails are formed with keyhole shaped apertures 8 which align when the components are assembled as shown figure 2 and 5. Carriage bolts or the like 8A with nuts threaded thereon are initially fitted inserted through the enlarged upper portions of the keyhole apertures and then moved down into and tightened across the narrow portions to hold the panels and rails together. This method has been found to greatly speed up the on-site assembly of the well. In order to improve access for fitting the bolts ports 9 may be provided adjacent the top of each panel as shown. This enables direct access to the keyhole apertures from the outside of the structure.

As will also be noted from figures 1 and 2 the corner rails 2 comprise a novel cross-section which in addition to the aforementioned flanges 7 includes inner facing slots 10 which open into vertical channels 11.

Turning now to figures 3 to 5 the floor or base 12 of the elevator cage is constructed with roller arms 13 extending diagonally out at or near each corner. These arms as shown in figures 4 and 5 extend into the aforementioned slots 10 of the corner rails so that the rollers 14 run in the vertical channels 11. Although not shown in the drawings a correspondingly placed set of four corner roller arms would also be fitted on or adjacent the top of the elevator cage.

This arrangement has been found to provide an efficient stable track for the cage which is cheaper to construct than prior art elevators requiring centrally disposed rollers guides along each side. With the embodiment shown the cage is operated by hydraulic rams located to each side 15. These react against the base or support structure 15A of the elevator well so that no significant load is carried by the wall panels 1 or corner rails 2.

It will thus be appreciated that this invention at least in the form of the embodiment described provides an improved form of elevator particularly suited to low cost residental and commercial construction. The novel substantially non load-bearing construction of the well and the provision of corner rollers for tracking the cage enables a low cost installation that can be assembled on site from light weight modular components. This substantially reduces costs with new construction and also allows such elevators to be added to existing buildings without expensive structural modifications. Clearly however the example disclosed is only the currently preferred form of the invention and a wide variety of modifications may be made which would be apparent to a person skilled in the art. For example the shape and configuration of the elevator well, the construction materials used and the design of the hydraulic lifting mechanism may be changed. In particular the non load-bearing cage and wall components of the well may be constructed from light weight materials other than sheet metal such as plastics, fibreglass or the like.