GB2271602A

GB2271602A - Ladder feet

Info

Publication number: GB2271602A
Application number: GB9321116A
Authority: GB
Inventors: Ian Spencer Clark
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-10-14
Filing date: 1993-10-14
Publication date: 1994-04-20
Anticipated expiration: 2013-10-14
Also published as: GB9221571D0; GB2271602B; GB9321116D0

Abstract

A ladder extension assembly comprising a sleeve 30 which is lockable, in a number of positions, to the lower end of a ladder rail 20, 24 enabling the ladder rail to be extended and a foot portion which supports the extended rail on uneven ground. The foot portion comprises a bar which is pivotally connected 21 at one end to the sleeve and at the other end to a base support member 74 such that the foot portion can move about two mutually transverse axes 71, 76 and thereby provide an improved support for the ladder user. <IMAGE>

Description

Improvements Relating to Ladders This invention relates to ladders, and addresses a problem which arises in connection with the use of ladders.

The main application of the invention is undoubtedly in relation to ladders, but as the explanation of the invention and the specific embodiment thereof are given herein, it will be seen that the invention may have application to other structures which comprise legs forming a support means.

Examples of such other structures are tripods and stepladders.

As is well known, a ladder comprises basically a pair of rails between which extend rungs or steps and ladders are used to enable people to gain access to locations which are normally out of reach. Mainly, ladders are used against the walls of buildings and are used by painters, window cleaners, decorators, builders and the like. Older forms of ladders comprise a pair of parallel wooden rails, and wooden or metal rungs or steps, whilst more modern ladders, and the majority of which are produced today, comprise metallic rails, specifically aluminium and rungs and steps of similar material.

The present invention has application to all forms of ladder, but it is particularly suitable for use in connection with the metallic ladders referred to above.

The problem which the present invention addresses is one concerned with the stability of the ladder when it is in use.

When a ladder is placed against for example a building wall its top end rests against the wall, and its bottom end rests on the ground. The angle at which the ladder lies to the wall is referred to herein as the resting angle, and the resting angle is chosen so that the ladder will remain stable as a user of the ladder climbs up and down same. The ladder will be naturally stable as long as the ground surface is horizontal, but should the ground surface slope such that the lower end of one of the ladder rails does not engage the ground when the ladder rests against the wall and is positioned vertically, then the ladder becomes particularly unstable, depending on the degree of slope.

In order to stabilize the ladder in such circumstances, it is common practise either to request a second person to hold the ladder steady and/or to apply his weight thereto, whilst a first person climbs the ladder, or alternatively a block or wedge is positioned under the appropriate lower end of the rail so that the lower ends of both rails will be stably supported.

The provision of a second person means extra expense and inconvenience and that person may not in fact be sufficiently strong to keep the ladder stable, depending upon the degree of slope and depending upon the height to which the ladder extends, and the use of a block or wedge is also not satisfactory because it can be dangerous, insofar as the block or wedge may move whilst the ladder is being used.

Ladder levelling devices which are intended to enable a ladder to be situated upright on an inclined or irregular ground or support surface are well known.

Devices which can be attached to one rail and devices provided to be attached to both rails of a ladder have been described for example in US Patent Nos 5107958, 5064024 and 4209078 and GB Patent No 2055943.

All these documents describe apparatus which serve to increase the length of one ladder rail relative to the other in order to compensate for an uneven surface.

Most of the prior art devices are complex and both difficult to manufacture and use. Although the majority of these ladder extenders have movable support feet, these supports are only able to pivot about a single axis, usually the axis parallel to the surface on which the ladder rests.

Hence it is unlikely that the base surface of each support foot of a device will support the weight of the ladder and its user whilst being in full contact with the surface upon which the ladder rests.

When considering this aspect of the prior art devices it is suggested that rather than preventing the ladder from rocking the devices may even increase the rocking action on the ladder because of the combined effect of the base of the feet not standing firmly on the support surface and movement caused by unsecure locking of the device to the ladder.

The present invention seeks to address this stability problem, and in accordance with the invention there is provided, a rail length extender assembly adjustably mounted on or adapted to be adjustably mounted on the lower end of a ladder rail so as to effectively extend the length of the rail, wherein a foot of the assembly which res.ts on the ground in use is so coupled to the remainder of the assembly as to be capable of articulation about at least two mutually transverse axes.

In a further aspect of the invention there is provided in or for a ladder, a pair of rail length extender assemblies which are adjustably mounted or adapted to be adjustably mounted on the lower end of the rails of a ladder so as to effectively extend the lengths thereof, wherein a rod member extends between said rails to lock the respective assemblies to some rails.

It can be seen by the invention that if the ladder rail length at one side of the ladder at least can be extended, then by appropriately positioning the extender assembly, the ladder can be made to stand vertical and stable in relation to a building wall or other surface against which the ladder rests, enabling the ladder to be used, without requiring the use of a separate block cr without requiring the presence of a second person to hold the ladder steady.

The or each extender assembly may comprise a sleeve portion and a foot portion, the sleeve portion being adapted to slip onto the end of the appropriate rail, and the foot portion being for engaging the ground.

The sleeve portion is preferably of a C-shaped cross section, so that the slot defined thereby provides a means through which the ladder rungs or steps can pass as the sleeve is adjustably positioned along the length of the ladder rail.

Preferably the assembly further comprises a member which is, at one end, pivotally interconnected to the sleeve and at the other end is pivotally interconnected to the foot of the assembly.

Preferably the member and the foot are pivotally interconnected for pivotal movement about an axis which in use will lie parallel to the wall or other surface against which the ladder rests and wherein the member and the sleeve are pivotally interconnected for pivotal movement about an axis which in use will lie perpendicular to the wall or other surface against which the ladder rests.

Preferably wherein the member and the foot are pivotally interconnected for pivotal movement about an axis which in use will lie perpendicular to the wall or surface against which the ladder rests and wherein the member and the sleeve are pivotally interconnected for pivotal movement about the wall or surface against which the ladder rests.

Preferably the invention provides two of said extended assemblies, one for each ladder rail. By providing two assemblies, the aesthetic appearance of the ladder when provided with the assemblies will be improved.

The or each assembly is adapted to be locked in adjusted position relative to the ladder rail by means of a pin and hole arrangement, the sleeve having a row of holes extending in the direction of the sleeve length, and the ladder rail being provided with at least one hole which can align with any of the holes in the sleeve, the pin serving to lock the rail and sleeve together by the insertion of the pin through aligned holes in the sleeve and rail.

The pin may in fact be a rod which extends across the width of the ladder and the rod may have a locking formation at one end thereof whereby, once the rod has been inserted to lock the extender assemblies in position, the end formation can be made to engage one of the assemblies to prevent the rod accidentally from being extracted. Alternatively the pin may be an elongate rod which is threaded at both ends and is longer than the distance between the outer faces of the ladder rails. In such a case the assemblies may be secured by the rod on to rails by threading a locking means such as a wing nut onto each end of the rod once the rod has been inserted through the aligned holes.This locking means has the added advantage that if only one assembly on a first rail requires adjustment the wing nut adjacent the first rail may be removed, the rod may be drawn towards the second rail, thereby releasing the first assembly, which can be adjusted to align an appropriate alternative hole on the sleeve with the hole on the rail. The rod is subsequently reinserted and the wing nut threaded onto the rod thereby securing the extender in its new position.

The invention applies where the extender assemblies are supplied for the retrofitting to existing ladders, or where they are embodied in new ladders. In the latter case the extender assemblies may be adapted so as to remain permanently connected to the ladder rails, although positionally adjustable thereon.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, wherein: Fig 1 is a side view showing how a conventional ladder is used by being positioned against a building wall; - Fig 2 is a front view of the arrangement of Fig 1; Fig 3 is an enlarged view showing the lower end of the ladder of Fig 1 but with extender assemblies according to an embodiment of the invention connected thereto; Fig 4 is a detail sectional view on the line IV-IV in Fig 3; Fig 5 is a detail sectional view taken on the line V-V in Fig 3; Fig 6 is a perspective view of the arrangement shown in Fig 3; Fig 7 is a perspective view of the locking bar which is also shown in Fig 3; Fig 8 is a view of a second locking bar; locking the sleeve portions to their respective rails Fig 9 is a view of a foot portion; and Fig 10 is a perspective view of the foot position in Fig 9.

Referring to the drawings, and firstly to Fig 1 and 2, reference numeral 10 represents a vertical building wall, and 12 represents the ground surface adjacent wall 10. A ladder 14 is shown as resting.against the wall 10 and standing on the ground 12. The resting angle of the ladder is indicated by reference 16.

As long as the ground 16 is horizontal, the ladder 14 will remain stable when a person climbs the ladder.

However, referring to Fig 2, should the ground 16 slope as indicated by a slope angle 18, then if the ladder 14 is positioned vertically as shown, at the lower end of the right hand rail 20 of the ladder, there will be a gap which typically in conventional practise will be filled by means of a block or wedge 22. The other rail 24 of course engages the ground as shown.

Even if block 22 is used as shown in Fig 2, upon the climbing of the ladder 14 by a person, the ladder may or could become unstable, and there is always a possibility that the block 22 might slip when a person is using the ladder, which is extremely dangerous especially if the ladder is particularly long.

The present embodiment of the invention seeks to overcome this difficulty, and if reference is made to Fig 3, it will be seen that the rails 20 and 24 are provided with a pair of extender assemblies 26, 28. These assemblies are of identical construction, except that they are "handed" insofar as assembly 28 is for connection to the left hand rail 24, whereas assembly 26 is for connection to the right hand rail 20. Because the assemblies are otherwise identical however, only one will be described in detail.

The assembly 26 is chosen for description, and it will be seen to comprise a sleeve portion 30; a member 70 and a foot portion 74. The sleeve portion 30 as shown in Fig 4 is of Cshaped cross section, and preferably it is an aluminium extrusion. The slot 32 provides a means whereby the rungs 34 of the ladder do not interfere with the sliding movement of the assembly 26, it being noted that the assembly 26 is slidable on the rail 20 as indicated by arrow 36.

Member 70 has a U-shaped bracket 71 as shown, One of the limbs 40 of bracket 71 extends into the interior of the sleeve portion 30, whilst the other limb 42 lies to the outside as shown. A bolt extends between the limbs 40 and 42, and the outer wall 44 of the sleeve 30 so that the member can pivot about the bolt axis 72 as shown clearly in Figs 3 and 9.

Member 70 has a second U shaped bracket 73, which is transverse to bracket 71, into which extends foot portion 74.

Foot portion 74 has a base pad 38 of rubber or the like friction material. A bolt 76 extends between limbs 82 and 84 and the foot portion 74 so that the foot portion can pivot about bolt axis 76 as shown in Figs 5 and 10.

Hence foot portion 74 is able to move about two mutually transverse axes relative to the assembly sleeve 30.

Reverting to Fig 3, the positioning of the extender assemblies relative to the ladder rails 20 and 24 enables the ladder with the assemblies to be stably positioned even when the ladder is used on ground such as ground 16 which lies at a slope 18 relative to the horizontal. This is achieved by the axial displacement of the extender assemblies relative to the rails 20 and 24, and as shown in Fig 3, the assemblies 26 and 28 are positionally adjustable as indicated by arrow 36 downwardly as shown by dotted lines and reference 50 in Fig 3 or upwardly again as shown by dotted lines at 52 in Fig 3.

To lock the extender assemblies in any adjusted position, a row of holes 54 is provided in the outer wall 44 of each sleeve portion 30, and the lower end of each rail 20 and 24 is provided with a through bore 56 and 58 which are aligned with each other, and which can be brought into successive alignment with the holes 54 in the sleeve portions. 30.

As a means for locking the extender assemblies in adjusted position there is provided a locking rod 58 which has at one end a formation 60 for locking to the adjacent extender assembly of ladder rail as described in relation to Figs 6 and 7.

Fig 6 shows the lower end of the ladder provided with the extender assemblies 26 and 28. The locking rod 58 is also shown in position in Fig 6, and Fig 7 is indeed a perspective view of a locking rod. In order to adapt the ladder for use on a slope as indicated in Fig 2, the assemblies 26 and 28 are relatively positioned on the rails as described hereinbefore, and then the locking rod 58 is simply threaded through the sleeve portions 30 via an aperture 54 in each sleeve portion, and the through bores 56 and 58 in the ladder rails. When the rod 58 is thus in position, it is twisted or rotated about its axis so that the formation 60 locks around the sleeve portion 30 or, in the case of Fig 6, the extender assembly 28.It will be understood that in Fig 3 the locking rod 58 is shown to the right-hand side of the ladder, whereas in Fig 6 it will be understood that the bar 58 has been inserted from the left-hand side of the ladder.

An alternative locking rod is shown in Fig 8. In this instance elongate locking rod 62 is inserted through assemblies 26 and 28 and their respective rails 20 and 24.

Rod 62 extends outwardly from assemblies 26 and 28 and is threaded enabling wing nuts 64 and 66 to be secured to the rods, thereby securing assemblies 26 and 28 to rails 20 and 24 respectively. If a single assembly say 26 requires adjustment, wing nut 64 is removed, rod 62 is pulled towards rail 24 releasing assembly 26. The assembly 26 is repositioned relative to rail 20 and rod 62 is inserted into newly aligned holes in rail 20 and assembly 26. It can clearly be seen that the same operation can be carried out to adjust assembly 28 relative to rail 24.

The present invention can take many forms, and it will be understood that a similar effect can be achieved by using only one extender assembly. The or each extender assembly may be formed as an integral part of new ladders, or they may be supplied as retrofit items.

It will also be understood that the basic idea can be applied to other stands such as tripods and step ladders which may have more than two support legs.

Claims

1. A rail length extender assembly adjustably mounted on or adapted to be adjustably mounted on the lower end of a ladder rail so as to effectively extend the length of the rail, wherein a foot of the assembly which rests on the ground in use is so coupled to the remainder of the assembly as to be capable of articulation about at least two mutually transverse axes.

2. An assembly in accordance with Claim 1 comprising a sleeve which is adjustably mounted or adapted to be adjustably mounted on the lower end of the rail.

3. An assembly in accordance with Claim 2 wherein said sleeve has a C-shaped cross-section such that the slot defined thereby provides a means through which the ladder rungs or steps can pass as the sleeve is adjustably positioned along the length of the ladder rail.

4. An assembly in accordance with Claims 2 or 3 and further comprising a member which is, at one end, pivotally interconnected to the sleeve and at the other end is pivotally interconnected to the foot of the assembly.

5. An assembly in accordance with Claim 4 wherein the member and the foot are pivotally interconnected for pivotal movement about an axis which in use will lie parallel to the wall or other surface against which the ladder rests and wherein the member and the sleeve are pivotally interconnected for pivotal movement about an axis which in use will lie perpendicular to the wall or other surface against which the ladder rests.

6. An assembly in accordance with Claim 4 wherein the member and the foot are pivotally interconnected for pivotal movement about an axis which in use will lie perpendicular to the wall or surface against which the ladder rests and wherein the member and the sleeve are pivotally interconnected for pivotal movement about the wall or surface against which the ladder rests.

7. The invention in accordance with Claims 2-6 wherein the assembly is adapted to be locked in adjusted position relative to the ladder rail by means of a pin and hole arrangement, the sleeve having a row of holes extending in the direction of the sleeve length and the ladder rail being provided with at least one hole which can align with any of the holes in the sleeve, a pin serving to lock the rail and sleeve together by the insertion of the pin through aligned holes in the sleeve and rail.

8. The invention in accordance with any preceding claim wherein two assemblies are provided, one for each ladder rail.

9. The invention in accordance with Claim 8 wherein there is a pin for each assembly.

10. The invention in accordance with Claims 8 wherein the pin is a rod which extends across the width of the ladder to lock both assemblies to the rails surrounded by the assembly sleeves.

11. The invention in accordance with Claim 10 whereas said rod further comprises an end formation which is engageable to one of the assemblies to prevent the rod from being accidently extracted.

12. The invention in accordance with Claim 10 wherein said rod is elongate and threaded at each end thereof, so as to extend outwardly from each rail/assembly combination, when in the locked position to enable securing means to be threaded onto each end of the rod to secure the said rail/assembly combinations.

13. The invention in accordance with Claim 12 wherein said securing means are wing nuts.

14. A ladder comprising at least one assembly in accordance with any of Claims 1-13.

15. An assembly in accordance with any of Claims 2-14 wherein said sleeve comprises an aluminium extrusion.

16. In or for a ladder, a pair of rail length extender assemblies which are adjustably mounted or adapted to be adjustably mounted on the lower end of the rails of a ladder so as to effectively extend the lengths thereof, wherein a rod member extends between said rails to lock the respective assemblies to said rails.

17. One or more assemblies substantially as hereinbefore described with reference to the accompanying drawings.