GB2055943A - Ladder-levelling device - Google Patents

Abstract

In order to level a ladder standing on uneven ground, an extension sleeve (1) is provided which fits over the lower end portion of the down- slope stile (13) of the ladder. The degree of insertion of the stile (13) into the sleeve (1) is adjusted to compensate for the unevenness of the ground and the sleeve (1) is then clamped to the stile (13). Aligned holes (10) provided in opposite walls (3) of the sleeve (1) serve to allow the insertion of a safety rod (11) just below the bottom of the clamped stile (13). The sleeve (1) can be press formed from a single piece of metal (1'). <IMAGE>

Description

SPECIFICATION Ladder-levelling device The present invention relates to a ladderlevelling device for compensating for any unevenness in the surface on which the ladder is standing.

It is common practice when using a ladder on uneven ground to underpin the down-slope stile of the ladder by using a convenient piece of wood.

However, such an expedient is generally unsafe and many accidents occur each year due to ladders coming off such temporary supports and toppling sideways.

According to the present invention, there is provided a ladder-levelling device comprising a sleeve into which the lower end portion of a stile of a ladder can be inserted, and clamping means for clamping the sleeve to the inserted stile, the extent of insertion of the stile being settable as required to compensate for any unevenness in the surface on which the ladder is standing.

The sleeve, which is preferably made of galvanised steel, acts as an extension, of adjustable length for the down-slope stile of the ladder. The device can be fitted to a ladder to enable its use not only on sloping ground but also on stairs. It will be appreciated that the device can be readily transferred between the two stiles of the ladder to compensate for either direction of slope of the surface on which the ladder is standing. Furthermore, since no special fitments are required to the ladder, the device can be used on most normal ladders now in use.

In one preferred embodiment, the sleeve of the device comprises two side walls interconnected by a back wall, and a front wall joined to the side walls. The front wall is angled to diverge from the back wall away from the zone of joining of the front and side walls. The clamping means takes the form of a screw clamp extending through the back wall of the sleeve. In use, the screw clamp clamps the stile of a ladder between its head and the front wall of the sleeve. Upon a load being put on the ladder, the stile inserted in the sleeve will tend to pivot about the head of the screw clamp and force itself into the narrowing space provided by the angling of the front walls. In this manner a safety jamming action is provided.

Advantageously, opposite sides of the sleeve are formed with aligned holes through which a safety rod can be inserted at a height to lie just below the bottom of a ladder stile positioned within the sleeve. This further increases the safety of the device.

A ladder-levelling device, embodying the invention will now be particularly described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a perspective view showing a ladder stile inserted in the device; Figure 2 is a developed view of a metal sleeve of the device; Figure 3 is a side elevation of the device; and Figure 4 is a section on line IV--IV of Figure 3.

As shown in the drawings, the ladder-levelling device comprises a sleeve 1 made, for example, from 14 gauge galvanised mild steel by press forming the metal piece 1' (Figure 2). The sleeve 1 comprises a back wall 2, two side walls 3, a bottom wall 4, and a front wall 5 joined to the side walls 3. In the present example, the front wall 5 is formed by two flanges which together define a central slot in the front of the sleeve 1; however, the wall 5 can alternatively be made to extend all the way between the side walls 3. Whichever form of front wall 5 is provided, the front wall 5 is angled to diverge from the back wall 2 away from the zone of joining of the front wall 5 with the side walls 3 (see Figure 4), A screw-threaded hole 6 is formed in the back wall 2 and a screw clamp 7 in the form of an eye bolt with a head 8 is engaged in the hole 6.

Alternatively to threading the hole 6, a metal nut 9 can be welded to the inside of the back wall 2 in alignment with the hole 6.

Respective series of holes 10 are formed in the side walls 3 of the sleeve 1 with each hole 10 in one series aligning with a corresponding hole 10 of the other series. A safety rod 11, attached by a polythene or wire line 12 to the clamp 7, is insertable through aligned ones of said holes 10.

The front end portion of the rod 11 can be made pivotal so that after insertion of the rod through the holes 10, this front end portion can be moved into a position in which it extends perpendicularly to the main portion of the rod 11 and thereby serves to secure the rod 11 against accidental removal. When not in use the rod 11 can be stowed in the eye of the eye bolt of the screw clamp 7.

In use of the device, the sleeve 1 is fitted over the lower end portion of the down-slope stile 13 of a ladder to be levelled. The extent of the insertion of the stile 13 into the sleeve 1 is adjusted to that required to level the ladder and the screw clamp 7 is then tightened up against the stile. The rod 11 can be used to aid tightening of the clamp 7. The safety rod 11 is then inserted through the holes 10 to lie just below the bottom of the stile 13.

Any loading of the ladder is transmitted to the surface upon which the ladder is standing both directly through the up-slope stile and indirectly through the down-slope stile 1 3 and the sleeve 1.

In addition to the clamping action provided by the clamp 7, there exists a jamming action of the stile 13 in the sleeve 1 due to the fact that loading of the ladder will tend to cause the stile 1 3 to rotate about the head 8 of the clamp 7 and move the stile into the narrowing space provided by the angling of the front wall 5. This gives increased safety in operation of the ladder-levelling device.

The provision of the safety rod 11 ensures that should the screw clamp 7 fail for any reason, the stile 13 can only move a very iimited amount into the sleeve 1.

By appropriately dimensioning the sleeve 1, the device can be arranged to fit most of the conventional wooden or aluminium round rung ladders now in use so that one device can be interchanged between several ladders as required.

The provision of the central slot in the front of the sleeve 1 enables the device to be used even for ladders having a bottom rung very close to the bottom of the ladder stiles. The device is stowable on a ladder stile by fully inserting the stile into the sleeve. With the device thus stowed, the ladder can be used normally.

A minimum insertion of the ladder stile 13 into the sleeve 1 of about 1 5 cm is desirable to ensure safe operation. The amount of extension provided by the sleeve 1 can be of the order of 23 cm which would enable the device to be used to level a ladder on stairs as well as on sloping and uneven ground.

The above-described ladder-levelling device is of simple construction and provides for increased safety at low cost. Furthermore, the device is highly versatile and easily used which is of great importance in achieving its acceptance by a labour force.

Claims (7)

1. A ladder-levelling device comprising a sleeve into which the lower end portion of a stile of a ladder can be inserted, and clamping means for clamping the sleeve to the inserted stile, the extent of insertion of the stile being settable as required to compensate for any unevenness in the surface on which the ladder is standing.

2. A device according to claim 1, in which the sleeve is press formed from a single metal piece.

3. A device according to claim 1 or claim 2, in which the sleeve comprises two side walls interconnected by a back wall, and a front wall which is joined to the side walls, the front wall diverging from the back wall away from the zone of joining of the front and side walls.

4. A device according to Claim 3, in which the front wall is formed by two flanges which are joined to respective ones of the side walls and which define a central slot in the front of the sleeve.

5. A device according to claim 3 or claim 4, in which said clamping means is a screw clamp extending through the back wall of the sleeve to clamp the said inserted stile between a head of the clamp and the front wall of the sleeve.

6. A device according to any one of the preceding claims, in which two opposite walls of the sleeve are formed with respective series of holes with each hole in one series aligning with a corresponding hole of the other series, the device including a safety rod insertable through aligned ones of said holes to lie in a position just below the bottom of a stile inserted in the sleeve.

7. A ladder-levelling device, substantially as hereinbefore described with reference to the accompanying drawings.