EP0073147A1

EP0073147A1 - Scaffold structure and levelling foot

Info

Publication number: EP0073147A1
Application number: EP82304396A
Authority: EP
Inventors: Andras Szucs
Original assignee: GKN Mills Building Services Ltd
Current assignee: RMD Kwikform Ltd
Priority date: 1981-08-28
Filing date: 1982-08-20
Publication date: 1983-03-02
Also published as: GB2104580A; GB2104580B

Abstract

A levelling foot for a scaffold structure comprises a ground engaging tubular member (28) having an axially adjustable rod (36) contained therein which carries the weight of the scaffold structure thereon. The rod (36) includes a bracket and spigot (38, 40) at its lower end projecting through a slot (32) in the tubular member (28) and adjustment means in the form of a link chain or a coarse pitch screw. The weight of the scaffold structure is supported on the rod bracket and spigot (38, 40) so that the rod (36) is only under tensile loading whilst the tubular member (28) is under compressive loading.

Description

This invention relates to a levelling foot for supporting builders scaffolding structure above the ground and wherein the foot is adjustable vertically to level the scaffold structure relative to the ground.
Conventionally, screw jacks are used to level scaffold structures. Such a screw jack usually comprises a threaded tubular member having a ground engaging foot and a rotatable part in screw-threaded engagement with the tubular member and with a lower end of the scaffold structure. Such a type of jack is thus subject to compressive loading under the weight of the scaffold structure and hence must be manufactured to a standard capable of safely accommodating the compressive loads applied to it in use.
It is an object of the present invention to provide a new or improved form of levelling foot for builders scaffolding structures which is quick and easy to operate and which is more economical of manufacturing costs than the screw jacks known in the art.
In accordance with the invention there is provided a levelling foot for a scaffold structure wherein the foot comprises a first elongate support member having a lower end engagable with the ground and a second elongate support member upon which the scaffold structure is supportable; the second support member being secured to the first support member by an adjuster for selectively varying the overall height of the foot, and hence enabling levelling of the scaffold structure, and whereby a tensile load is applied to the second support member by the weight of the scaffold structure.
The first support member is conveniently of tubular form and the second support member is telescopically adjustable therein. The second support member may have a support thereon extending out of the first support member through an axially extending slot therein; the lower end of the scaffold structure being supported on the support.
In one embodiment the second member may have a chain adjuster connected thereto for selective engagement with the tubular member. Such adjuster may comprise a length of link chain secured to the second member and wherein a link of the chain is selectively engagable within a recess in the top of the tubular member.
Alternatively the second member may have a coarse pitch helically-threaded external surface engaged with a complimentarily threaded nut carried on the tubular member for effecting axial adjustment of the second member relative to the tubular member.
In any of these embodiments the support conveniently comprises a bracket projecting through an axially extending slot in the tubular member and having a spigot on the bracket for engagement within an end of a scaffold tube of the scaffold structure to be supported thereon.
Other features of the invention will become apparent from the following description given herein solely by way of example with reference to the accompanying drawings wherein

Figure 1 is a diagrammatic perspective view of a ladder-type triangular access scaffold structure supported at each of its three corners on levelling feet constructed in accordance with the invention;
Figure 2 is a front elevation of one embodiment of levelling foot having a tubular first member and a second member in the form of a rod contained within the tubular member, the adjustment means being omitted;
Figure 3 is a side elevation of the members shown in Figure 2;
Figure 4 is a side elevation of the rod of the Figure 2 embodiment showing a link chain adjuster secured to the top end of the rod;
Figure 5 is a scrap perspective view of the top end of the tubular member showing the link chain engaged therewith;and
Figure 6 is a scrap side cross-sectional view of the upper end of an alternative embodiment of levelling foot in accordance with the invention.

Referring to Figure 1 of the drawings there is shown an item of builders scaffold structure in the form of the lowermost lift 10 of a ladder-type triangular access tower. Normally a plurality of such lifts will be assembled one above the other by spigot and socket connectors to provide an access tower to a required height. As illustrated, the lowermost lift comprises three uprights 12, 14 and 16 defining the three corners of the tower, two of which uprights 12 and 14 are interconnected by scissor bracing 18-20 and being connected to the third upright 16 by horizontal transoms 22. Such an item of scaffold structure can be formed of either steel or aluminium having standard diameter scaffold tubes and can be folded for compact storage and/or transportation by disconnecting the joint 24 at the point of intersection of the scissor bracing 18-20.
As illustrated in Figure 1, a levelling foot 26 constructed in accordance with the present invention supports the scaffold structure at each of its corners for effecting levelling of the structure relative to the ground on which the feet rest. As shown in more detail in Figures 2 to 5, each levelling foot 26 comprises a first member in the form of an elongate tube 28 having a ground engaging foot 30 at its lower end and a slot 32 extending axially of the tube upwardly from the foot. Part of the wall of the tube 28 is cut away at its upper end to provide a recess 34 for a purpose which will be further described.
The foot 26 also includes a second member in the form of an elongate rod 36 axially movable within the tube 28 and having a bracket 38 at its lower end which projects outwardly of the tube 28 through the slot 32. The bracket 38 carries an upstanding spigot 40 thereon for engagement within the lower end of an upright standard scaffold tube of the scaffold structure, such as one of the uprights 12, 14 or 16 of Figure 1. The upper end of the rod 36 has a link chain 42 connected thereto, any link of which is selectively engagable within the recess 34 at the upper end of the tube 28.
Thus the rod 36 is axially adjustable within the tube 28 and securable in position by manual selective engagement of a link of the chain 42 within the recess 34. Since the lower end of a scaffold tube of the scaffold structure is supported on the spigot 40 of the bracket 38 secured to the lower end of the rod 36, the foot can be used to selectively adjust and level the scaffold structure relative to the ground. In the case of the triangular tower structure 10 of Figure 1, the three feet 26 can be adjusted to raise or lower the associated uprights 12, 14 and 16 and level the structure.
As will be seen from Figure 4 the rod 36 is provided with two spaced discs 37 and 39 welded to the rod at its lower end. The outside diameter of the discs 37 and 39 matches the inside diameter of the tube 28. Thus, in use, the discs 37 and 39 bear on the inside surface of the tube 28 generating horizontal forces which constitute a restraining couple at the lower end of the rod 36. This couple is necessary to balance the bending moment which is created by the offset of opposing vertical forces whose lines of action are along rod 36 and spigot 40 respectively. Without the provision of these discs 37 and 39, the rod 36 would bend and the bracket 38 would tilt downwards.
Although not shown in detail, each levelling foot 26 is also provided with guide means for engagement with the associated upright scaffold tube of the scaffold stucture. Such guide means are conveniently in the form of sleeves attached to the tube 28 or to the uprights 12, 14 and 16 through which the upright or foot respectively is guidable to rest on and be supported by the bracket and spigot 38-40 on the rod 36.
An alternative form of adjuster for a levelling foot in accordance with the invention is shown in Figure 6 wherein the first member of the foot is again in the form of an elongate tube 28 having a ground engaging foot and a slot extending axially upwardly of the tube from the foot. In this embodiment the second member is in the form of a rod 36 having a coarse pitch helically-threaded surface engaged within a complimentarily threaded nut 44 rotatably carried in the open top of the tube 28. A set screw 46 projects through an aperture in the upper end of the tube 28 to be engagable with the nut 44 for preventing rotation thereof and preventing axial movement of the rod 36. Axial adjustment of the rod 36 relative to the tube 28 is effected by releasing the set screw 46 and permitting rotation of the nut 44 relative to the rod 3-6. The lower end of the rod 36 will carry a bracket and spigot to project through the slot in the tube similar to that described with reference to the first embodiment herein and similar guide sleeves for the uprights of an associated scaffold structure supported by the foot may also be provided. The lower end of the rod 36 will also carry bearing discs to co-operate with the tube 28 for the same purpose as has been described with reference to the first embodiment herein.
Thus in both of the embodiments described herein the weight of the scaffold structure is transmitted to the tube 28 comprising the first member through the rod 36 comprising the second member of the levelling foot in such manner that tensile loading is applied to the rod 36. It is known that comparatively greater loads can be carried in tension than in compression and hence the levelling foot in accordance with the invention may be constructed more economically of lighter stength materials than would be the case if all the elements of the foot were being used in compression. Of course compressive loads are applied to the tube 28 comprising the first member of the foot but the rod 36 comprising the second member only has tensile loads applied thereto.

Claims

1. A levelling foot (26) for a scaffold structure (10) characterised in that the foot (26) comprises a first elongate support member (28) having a lower end (30) engagable with the ground and a second elongate support member (36) upon which the structure (10) is supportable; the second member (36) being secured to the first member (28) by an adjuster (42, 44) for selectively varying the overall height of the foot (26) and hence enabling levelling of the structure (10) and whereby a tensile load is applied to the second member (36) by the weight of the scaffold structure (10).

2. A levelling foot as claimed in Claim 1 further characterised in that the first member (28) is of tubular form and the second member (36) is telescopically adjustable therein.

3. A levelling foot as claimed in Claim 2 further characterised in that the second member (36) has a support (38, 40) thereon extending out of the first member (28) through an axially extending slot (32) therein; the lower end of the scaffold structure (10) being supported on the support (38, 40).

4. A levelling foot as claimed in any one of Claims 1 to 3 further characterised in that the adjuster (42) comprises a length of link chain secured to the second member (36) with a link of the chain (42) being selectively engagable within a recess (34) in the first member (28).

5. A levelling foot as claimed in any one of Claims 1 to 3 further characterised in that the adjuster (44) comprises a helical coarse pitch internally threaded nut carried by the first member (28) and engaged with a complimentary external thread on the second member (36).

6. A levelling foot as claimed in Claim 5 further characterised in that the nut (44) is non-rotatably carried by the first member (28).

7. Builders scaffold structure (10) including at least one levelling foot (26) characterised in that tne foot (26) is constructed as claimed in any one of Claims 1 to 6.