GB2146378A

GB2146378A - Safety device for a ladder

Info

Publication number: GB2146378A
Application number: GB08324356A
Authority: GB
Inventors: Michael Charles Jenkins
Original assignee: Terence Lee
Current assignee: Terence Lee
Priority date: 1983-09-12
Filing date: 1983-09-12
Publication date: 1985-04-17
Also published as: GB8324356D0; GB2146378B

Abstract

A safety device for inhibiting the lower end of a ladder (38) from slipping away when the ladder (38) is in use, comprises at least one leg (12) which has attachment means (10) at one end to enable it to be attached to a lower end region of a ladder (38). When the device is in use, the or each leg (12) extends from the attachment means (10) to a position on the ground which is spaced from the ladder, and has, with a lower part of the ladder (38), a triangular construction to inhibit rotation of the leg relative to the ladder (38) in a sense opposite to that in which the ladder (38) would rotate relative to the ground were its lower end to slip away. <IMAGE>

Description

SPECIFICATION Safety Device for a Ladder The present invention relates to a safety device for inhibiting the lower end of a ladder from slipping away when the ladder is in use.

Hitherto, means for achieving this may comprise simply rubber feet at the base of a ladder to reduce the likelihood of slipping of the ladder. In many instances this has proved inadequate, and many accidents have arisen when the base of the ladder has not been firmly secured to an anchor point or has not been "footed" by a colleague.

The present invention seeks to overcome this problem by providing a device which positively holds the lower end region of a ladder against slipping.

Accordingly, the present invention is directed to a safety device which is attached to the lower end of a ladder when the device is in use and extends behind that lower end, to contact the ground and thus inhibit the lower end from slipping away when the ladder is in use. Such a device comprises at least one leg which has attachment means at one end to enable it to be attached to a lower end region of a ladder and to extend therefrom to a position where it contacts the ground when the device is in use, the device being so constructed as to inhibit, when the device is in use, rotation of the leg or legs relative to the ladder in a sense opposite to that in which the ladder would rotate relative to the ground were its lower end to slip away.

In one particular form of this construction, there is a frame to which are attached hooks so spaced apart relative to one another that they can hook underneath two rungs at the lower end of a ladder when the ladder is propped up against a wall or other object, and two legs which are spaced apart and which extend rearwardly of and downwardly from the frame to the ground, when the device is in use, the legs being rigidly secured to the frame against upward rotation about the frame.

It will be appreciated that when such a device is in use, it actively holds the lower end of the ladder against slipping away. The principle of its operation can be understood if one considers what would happen were sufficient force to be exerted on the base of a ladder for it to slip away. Such slipping would result in a rotation of the ladder relative to the ground which would urge the legs of the device into the ground. Since the legs will not yield, owing to their rigid attachment to the frame of the device against upward relative rotation thereabout, the only way in which the base of the ladder can slip away is by an upward lifting of the bottom end of the ladder from the ground. Clearly, if a man is standing on the ladder at the time, this would require a considerable force.Certainly the horizontally directed force required to move the base of the ladder away from the wall in this way would greatly exceed any horizontal component of the force which the user himseif exerts on the base of a ladder owing to his standing on the ladder or climbing the ladder. In this way, the safety device positively holds the ladder against slipping away. To provide even greater security, holes or recesses may be provided at the base of the legs through which spikes or other fixing means may be driven if the device is rested on soft ground or other ground that will receive such fixing means.

One example of a safety device in accordance with the present invention is illustrated in the accompanying drawings in which: Figure lisa perspective view of the device resting on the ground; and Figure 2 is a perspective view of the device in use attached to the lower end of a ladder which is propped up against a wall (not shown), for example.

The device shown in Figure 1 comprises an aluminium frame 10 and two legs 12 extending rearwardly and downwardly from the frame 10 to the ground.

The frame loins made up of two generally upright mutually-parallel bars 14firmly held with this relative positioning by upper and lower cross-bars 16 and 18 bolted to the uprights 14. The frame is provided with an upper and a lower pair of hooks 20, the hooks of each pair being spaced apart horizontally. The lower hooks 20 may be formed by curved bottom ends of the uprights 14. The upper pair of hooks may be formed separately and bolted respectively to the uprights 14. An L-shaped bar 22 is releasably bolted to the centre 24 of the uppercrossbar 16.

Each leg 12 comprises two bars 26 and 28 having respective ends bolted to upper and lower ends of one of the uprights 14, the other ends of the leg bars 26 and 28 being bolted together to define the lower end of the leg. Each leg 12 is therefore part of a triangle defined by two bars 26 and 28 and one of the uprights 14 and is therefore rigid against upward relative rotation about the frame 10. The lower end of each leg 12 is provided with a plate 30 which has an L-shaped cross-section and which has an upwardly extending part of the "L" pivotally secured to the lower end of the leg 12. The plates 30 can thereby act as feet with a horizontally extending part of the "L" lying flat on the ground, substantively irrespectively of the relative angle of the safety device relative to the ground. Fixing holes 31 are provided in the plates 30.

The legs 12 are splayed apart so that they diverge in a direction away from the frame 10, thereby to give greater lateral stability to the device. They are firmly held in this manner by means of a cross-bar 32 which is bolted to respective lower end regions of each bar 26 of the legs 12.

The frame 10 is shown in Figure 1 slanting backwardly slightly with an angle relative to the ground which matches the desired angle of a ladder when it is propped up correctly against a wall or other object.

With the safety device positioned in this way, a ladder 38 may now be propped up against a wall or other upright surface or object (not shown) with its bottom two rungs 40 and 42 slid into the hooks 20 as shown in Figure 2.

It can be seen that the upright bars 14are positioned directly behind the bottom two rungs in this way, and not behind the two uprights 44 and 46 of the ladder. Consequently a ladder of substantially any width can be held by the safety device. The spacing between rungs of different ladders in the United Kingdom is generally of a fixed standard distance. Nonetheless, different spacings of rungs of different ladders may be accommodated by means of a number of holes 48, shown in Figure 1, in the uprights 14 which can be used selectively to attach the upper hooks 20 at different vertical positions.

The device will remain in this position relative to the ladder, but for additional security, particularly in the event that the ladder is lifted to be moved along, the L-shaped bar 22 may be secured with its shorter length hooked over the top of the rung 40 of the ladder.

The safety device is then in its operative position in which it actively holds the ladder from slipping away.

If the device is resting on soft ground, spikes for example may be driven through the holes 31 in the plates 30 to hold the device even more firmly in position.

Different heights or angles for the frame 10 may be selected by having the upper bars 26 of each leg 12 made of two lengths 26a and 26b. Along mutually overlapping portions of these two lengths are a number of spaced apart locating holes 50, as shown in Figure 1.

Numerous modifications are possible without departing from the scope of the present invention. A differentA4rame structure may be used. In one possible, although less desirable, construction the device may comprise simply at least one wide leg which is held at the bottom end of the ladder and extends rearwardlytherefrom along the ground, this leg being held in such a manner that it can not rotate upwardly towards the ladder. A strong plastics material with high tensile strength may be used for the device instead of aluminium. Also, an industrial form of the device would use thicker material, possibly thick mild steel for example, and would have basically a longer frame with larger feet.

Claims

1. A safety device for inhibiting the lower end of a ladder from slipping away when the ladder is in use, the device comprising at least one leg which has attachment means at one end to enable it to be attached to a lower end region of a ladder and to extend therefrom, when the device is in use, to a position on the ground which is spaced from the ladder, the device being so constructed as to inhibit, when the device is in use, rotation of the leg or legs relative to the ladder in a sense opposite to that in which the ladder would rotate relative to the ground were its lower end to slip away.

2. A safety device according to claim 1, in which the or each leg comprises first and second elongate members which are joined to one another at a position which, when the device is in use, is spaced from the ladder and which are also fixed at positions on the ladder which are spaced from one another, so that the said first and second elongate members and a lower portion of the ladder define a triangle when viewed from the side.

3. A safety device for inhibiting the lower end of a ladder from slipping away when the ladder is in use, the device being substantially as described herein with reference to the accompanying drawings.