"Ladder stabiliser"

The present invention relates to an accessory for a ladder. More particularly it relates to a device for stabilising a ladder, thereby improving the safety of the ladder user.

Many building, decorating and repair jobs require the use of a ladder but it is often found that the • ideal conditions for ladder use are not available. Most ladders have only two small points of contact with the ground, at the base of each stile, and it is therefore essential that the ground line is entirely level and unyielding. Uneven or soft ground can allow the ladder to slip, and it is particularly dangerous if the base of the ladder slips outwards away from the wall . Even on hard, level ground the base of the ladder can slip outwards if its angle to the vertical is greater than 20-30° and it is usually recommended that the distance of the ladder foot from the wall or other vertical surface should be as near as possible to one quarter of the height reached by the top of the ladder. Such safety requirements impose severe limitations on the situations where the safe use of a ladder is possible and tends to invite the use of unsafe practices.

The problems of safe ladder use are well appreciated and a number of safety devices are known in the art. These include simple boards on which the ladder is stood, having an upwardly directed lip to prevent outward movement of the ladder base, rope stays tied at one end to a ladder stile or rung and secured at the other end either to the vertical working surface or

to a stake driven into the ground beneath the ladder, and a wide variety of permanent or detachable ladder feet.

Such ladder feet may take the form of suction pads, simple serrated base plates or articulated feet intended to compensate for a slightly uneven ground line. None of these devices provides a perfect solution to the problem and most require either a fairly permanent attachment to the ladder or some form of adjustment and readjustment each time the ladder is moved.

Published British Patent Application No. 2166793 discloses a device comprising two brackets welded to the upper ends of respective box-section leg parts, interconnected at their lower ends by a rod, each bracket having two hook parts which engage the respective opposite edge faces of the ladder stiles. This type of ladder stabiliser is simple to attach and detach from the ladder. However, this device will safely fit only a single size and shape of ladder stile which necessitates its production in a number of designs and sizes in order to fit different types of ladder. This is a major disadvantage both for the manufacturer and retailer, who must deal with the problems and expense of several manufacturing lines, multiple packaging designs, and ordering and stocking a range of similar products, and for the final user who must purchase the correct size and design of stabiliser for the intended ladder use. Users may well have access to more than one type of ladder and may need separate stabilisers for each one. In addition, the rod connecting the lower ends of the two leg parts makes the device unwieldy and prevents the positioning of the legs at different levels, as may

be desirable, for example, on very uneven ground or where one ladder stabiliser has to be placed at a higher level, such as on a step. •

Published British Patent Application No. 2195693 discloses a stabiliser device for attachment to a ladder, having an attachment portion adapted to be attached to a stile of a ladder and a leg portion connected to and extending away from the attachment portion. The attachment portion is provided with two projections of adjustable length extending outwardly therefrom and positioned such that the stile can pass freely therebetween when the axis of the stile, the projections, and a line joining the projections are generally mutually perpendicular, and such that the projections engage the respective edge faces of the stile when the device is rotated about an axis generally parallel to the rungs of the ladder.

In operation the adjustable projections of GB 2195693 allow the device to be attached to a ladder stile sufficiently firmly to provide safe support for the ladder, but the attachment does not prevent the device from sliding down the stile until the device firmly engages both the ground and the edge faces of the ladder stile. This provides great convenience in use, since the device may be fitted to the ladder above its desired position and then simply allowed to settle down to its final position.

Essentially, the downward force caused by a user placing his weight on the ladder causes the device to twist and lock against the stile, allowing around a quarter of the force placed on the ladder to be

transmitted to the leg portion. This greatly increases the stability of the ladder.

In one form the device is an anchor for attachment to a ladder stile near the bottom of the ladder and operates such that forces on the ladder in use cause an increase in the force of engagement of the projections with the respective edge faces . In another form, the device is a ladder stay adapted to be attached to a ladder stile near the top of the ladder for holding the top of the ladder away from the wall. Again the force of the ladder on the device and the reaction of the wall on the device cause an increasing engagement between the projections and the edge faces of the stile.

Each projection comprises a pin which is slidably fitted into a corresponding receiving hole in the attachment portion and clamped into position.

While the length of the pins can be adjusted to allow for different stile thicknesses, the pins are at a fixed distance from one another, defined by the receiving holes within the attachment portion. This limits the range of stile widths (i.e. the distance from one stile edge to the other) that the device can safely be applied to.

If a thin stile is used with the ladder stabiliser of GB2195693 the projections may not engage with the stile until the device has rotated so far about the axis that it no longer assists in stabilisation. Further, if the device is used with a particularly thick stile it is possible the device will lock straight away and hence the adjustability of the device is lost.

In order to allow the stabiliser to be used .with narrow stiles a number of separate collars and spacers

are provided. The collars are slid onto the pins together with the required number of spacers to increase the length of the collar stem to match the stile thickness . This has the effect of increasing the diameter of the pins so that they engage the stile edges at a smaller rotational angle.

This technique therefore requires the manufacture of a number of additional parts, increasing the cost and complexity of the device. The user must store and transport these components until such time as they are required, leading to the possible loss or damage of these pieces. Finally, when required the collars and spacers must be correctly assembled by the user, which is time consuming and inconvenient. It is possible that many users would simply decide not to bother adding the collars to the pins and use the stabiliser without these, leading to unsafe ladder use.

Therefore a more simple, cost effective means of adjusting the stabiliser for different, in particular narrow, stile widths is required which can be operated quickly and simply by the user without the need for excess parts .

Viewed from one aspect the present invention provides a stabiliser device for attachment to a ladder, comprising an attachment portion adapted to be attached to a stile of a ladder and a leg portion connected to and extending away from the attachment portion, the attachment portion being provided with two projections extending outwardly therefrom and positioned such that a stile receiving gap is formed between the projections, such that when a stile is positioned within the stile receiving gap and the device is rotated about an axis

generally parallel to the rungs of the ladder, the projections engage the respective edge faces of the stile, wherein at least part of at least one projection is repositionable with respect to the attachment portion such that the width of the stile receiving gap can be altered through repositioning of the projection.

Within this specification the ' sides ' of a ladder are the directions to the left and right of a user standing on the ladder, so the side faces of the stiles are the faces normally intersected by the axes of the rungs . The front and rear of the ladder are the portions facing towards and away from the user respectively and the edge faces of the stiles are thus the front and rear faces of the stiles, which are generally perpendicular to the side faces.

By allowing one or both of the projections to be at least partially repositioned relative to the attachment portion the stile receiving gap can be altered without the need for additional components. As the projections are always in use there is no possibility of these becoming lost or forgotten and therefore the user is much more likely to adjust the stabiliser for correct use.

In some embodiments the projection is repositionable linearly with respect to the attachment portion, for example slidable along a groove or slit. In such embodiments the locking mechanism used to hold the projection in place simply needs to be loosened and, once the projection has been moved to its new position, retightened. Alternatively the projection (s) can be moved by a ratchet and pawl or other incremental means integrated with the attachment means .

It is preferred however that at least part of the projection is angularly repositionable in order to alter the width of the stile receiving gap. In order to achieve this at least part of the projection must be shaped such that, as its angular orientation is altered, the width of the stile receiving gap changes. The proj.ection must therefore have surfaces at different distances from the axis about which, during use, the orientation of the projection is adjusted. Preferably therefore the at least one projection comprises an engagement portion for engaging the stile, the engagement portion comprising at least two engagement surfaces angularly spaced from each other such that by adjusting the angular orientation of the engagement portion relative to the attachment portion different engagement surfaces are aligned with the stile receiving gap to alter its width.

An engagement surface is said to be aligned with the stile receiving gap when the surface faces the gap such that, when a stile is positioned within the stile receiving gap and the device is rotated about an axis generally parallel to the rungs of a ladder, it is the aligned engagement surface which engages the ladder stile. This preferred embodiment allows the width of the stile receiving gap to be altered simply by adjusting ^■ the angular orientation of the engagement portion of the projection relative to the attachment portion. The engagement portion could be a collar permanently and rotatably fastened to an inner core of the projection, the inner core being fixed in relation to the attachment portion. In this way only part of the projection has to

be repositioned in order to adjust the stile receiving gap. However, preferably the engagement portion is integral with the projection such that alteration of the angular orientation of the engagement portion is achieved by altering the angular orientation of the projection.

Preferably the attachment portion comprises housing means for holding the protrusions in a desired orientation relative to the attachment portion. Preferably this housing means comprises a receiving hole for slidably receiving said at least one projection and means for securing the projection in position. This allows the length of the projection to be adjusted to account for a variety of stile thickness. The securing means can be any device which can fix the projection in relation to the attachment portion. For example, the projection could comprise a number of through holes spaced along its length and extending radially through the projection and the securing means a pin that can be slid through a particular through hole and corresponding holes in the housing means to fix the projection in place. Preferably the securing means is in the for of clamping means which hold the projection in place by compression or bracing. Preferably the clamping means comprises a pad bolt having a cut-away region which may engage with the projection and which engagement may be tightened by pulling the pad bolt in a direction generally perpendicular to the longitudinal axis of the projection and fastening said pad bolt in position.

Preferably each projection has a portion at its free end which extends in a direction perpendicular to

its longitudinal axis to define a retaining means which can engage the inner side face of the stile to prevent the device from becoming detached during use.

In some embodiments the projection can be placed in any orientation by the user. In such embodiments it is preferred however that the user is given an indication of when each engagement surface has been correctly aligned, e.g. the housing means could comprise a biasing member arranged to press against the projection, the projection containing grooves or indents into which the biasing member is forced when an engagement surface is aligned with the stile receiving gap. This also helps to provide some resistance to further radial movement, preventing the accidental displacement of the projection. However it is preferable that the housing means can only receive the projection when in number of limited orientations.

Having finite, discrete positions in which the projection can be held ensures the engagement surfaces are correctly aligned with the stile receiving gap. The user must move the projection into one of a number of limited allowed orientations and cannot accidentally place the projection in an intermediate position which would create an incorrect size of stile receiving gap. Preferably the at least one projection comprises a pin having a head and a shaft, wherein the engagement portion is formed by at least part of the shaft and the head forms the retaining means .

This allows a projection to be formed in which the engagement portion comprises only part of the shaft. In such an embodiment another portion of the protrusion, to be slidably received within the receiving hole, can be

circular. This allows the orientation of the projection to be altered by rotating the projection whilst this is still held within the housing means. In such embodiments the projection can be held at any orientation.

However, as mentioned previously it is preferred that the projection can only be held in a limited number of orientations and so preferably the engagement portion runs the length of the shaft. In other words, the engagement portion comprises the entire pin shaft. This eases production of the pin shaft and has advantages for ensuring the projection can only be housed in certain orientations .

Preferably the shaft is cylindrical and comprises a protrusion, said cylindrical shaft forming a first engagement surface and said protrusion forming a second engagement surface. The protrusion extends beyond the radius of the cylinder and thus, when aligned with the stile receiving gap, decreases the width of the stile receiving gap in relation to when the first engagement surface is in alignment. The protrusion preferably subtends an angle of less than 180°, preferably less than 90° and most preferably less than 45°.

When only two engagement surfaces are desired only a single protrusion is necessary. If more engagement surfaces are required further protrusions can be included at different angular positions around the shaft. Preferably the projection and housing means are arranged such that the orientation of the projection must be adjusted by around 90° to alter the stile receiving gap. When the projection comprises a single protrusion this ensures a smooth, uniform section of the

shaft is presented to the clamping means in both orientations of the projection.

As well as the above configuration the projection could also be many other shapes. For example, the projection may have a planar shape which can be fitted into a cross shaped receiving hole in either an upright or horizontal position.

Preferably at least part of both projections are repositionable to alter the width of the stile receiving gap. This allows a greater variation in stile receiving gap widths with a simpler design of projection.

When each projection has two engagement surfaces, as described above, three different sizes of stile receiving gap can be created. Firstly when both projections are in a first position, with first engagement surfaces facing the stile receiving gap, secondly when both are in a second position, with second engagement surfaces facing the stile receiving gap, and thirdly when one projection is in the first position and the other is in the second.

The dimensions of the protrusions and their ^' positioning in relation to the attachment portion can be adjusted depending on the sizes of ladder stile the device is intended for use with. Preferably the projections are arranged to provide stile receiving gaps suitable for stile widths of between 50-90πtm more preferably 54-84mm. Preferably the difference between maximum and minimum stile receiving gap widths is between 10 and 20mm, more preferably 14mm. It has been found that this provides a wide enough range of stile receiving gap to accommodate most domestic, DIY and light trade ladders. However, it is of course possible

to adjust these dimensions to create stabilisers having stile receiving gaps of any width, e.g. larger widths for larger trade ladders .

The invention is not limited to use with ladders having stiles of a rectangular cross-section: it may be used with virtually any cross-section.

The attachment and leg portions may be constructed of metal such as, for example, steel or aluminium alloy, or of moulded plastics or of composite materials, and preferably are an integral metal die casting. The projections may also be of metal or plastics material and are preferably _, of glass-filled nylon.

The inner face of the attachment portion which engages the outer side face of the ladder stile may be further provided with a relieved channel running generally transversely to a line joining the two projections. Preferably the recessed channel has a hollow dome region generally central to its longitudinal axis . The inner face of the attachment portion between and immediately adjacent to the two projections would lie in parallel contact with the outer side face of the ladder stile when the device is In use whirlst the recessed channel may pass freely over any protrusions projecting from the approximate midline of the stile face. The central region of the inner face of the attachment portion may be the base of a generally hollow dome. The absence of material at this central region further aids in avoiding projections.

The leg portion connected to the attachment portion is preferably directed slightly outwardly in use so that the area enclosed by the four points of ground contact, i.e. the two ladder anchor feet and the two ladder

stiles, is large, thus improving stability by increasing the moment required to tilt the ladder sideways.

The leg portion may be of uniform cross-section or may taper to provide a point to embed in soft ground or may provide a wider contact area with the ground if it is preferred that the leg should rest on the surface of the ground. Any known kind of ladder foot may be attached to the 'leg, such as friction or suction pads or an articulated foot. The two ladder stabilisers for attachment to the respective stiles of a ladder are preferably mirror images of each other.

Some embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Fig. 1 is a front view of a pair of ladder stabilisers according to the invention attached to the stiles of a ladder;

Fig. 2 is an exploded view of the left-hand ladder stabiliser of Fig. 1;

Fig. 3 is a perspective view of the projection of the present invention in the form of a pin;

Fig. 4 is a view of the assembled ladder stabiliser of Fig. 2 with the pin heads removed; Figs . 5A-B are views of alternative orientations of pins within the stabiliser;

Fig 6 is a front view of the attachment portion;

Fig. 7 is an outside side view of the right-hand stabiliser anchor of Fig. 1; Fig. 8 is a cross-sectional view of the stabiliser of Fig. 7 through the plane X-X;

Fig. 9 is a perspective view of the stabiliser of Fig. 7 from the direction Y; and

Fig. 10 is a perspective view of a preferred embodiment of a stabiliser foot. Stabilisers 1 and 2 are intended to be used in pairs as shown in Figure 1. Each pair comprises a left- hand stabiliser 1 for attachment to the left-hand ladder stile 3 and its mirror image comprising the right-hand stabiliser 2. Each stabiliser comprises an attachment portion 5 and a leg portion 4. The leg portion 4 of each stabiliser extends outwardly from the attachment portion 5 such that the distance between the two points of contact of the stabiliser legs with the ground is greater than the distance between the ladder stiles . This enhances the stabilising effect.

Each attachment portion is attachable and moveable independently of the other. This provides excellent benefits when using the ladder on uneven ground or awkward spaces as each stabiliser can be positioned at different heights or against different surfaces without effecting the positioning of the other stabiliser. Each attachment portion is provided with two projections 6 which engage the opposite edge faces 10, 11 of the ladder stile when the device is attached thereto . In a preferred embodiment the attachment portion 5 and leg portion 4 are formed as an integral metal die casting whilst the projections 6 are of moulded plastics material such as, for example, glass- filled nylon. Figure 2 shows an exploded view of left hand stabiliser 1. In this preferred embodiment the two projections 6 comprise pins with shafts 7 which fit

slidably into corresponding holes 17 within the attachment portion 5. A stile receiving gap is formed between the pins when these are inserted into the holes 17. The pins may be of solid design or may be hollow optionally with, for example, a number of interior reinforcing ribs extending radially from a central core for improved strength. Each pin is provided at one end with a retaining means in the form of a flattened head 9 which may be an integral part of the pin or separately manufactured and fastened to the pin shaft by any conventional means .

Shafts 7 are cylindrical in shape with a protrusion 8 extending along the entire length of the shaft 7. Holes 17 are cylindrical with two cavities 17a, 17b. The holes 17 are shaped in this way to allow the pins to be inserted in two positions, firstly with the protrusions 8 facing downward, fitting within cavity 17a, and secondly with the protrusions 8 facing towards the centre of the attachment portion 5, within cavity 17b. This allows different engagement ^' surfaces of the pins to be positioned facing the stile receiving gap.

Figure 3 shows a pin in isolation. In this embodiment the pin shaft 7 is hollow. Protrusion 8 can clearly be seen. Head 9 is shaped to indicate the position of the protrusion 8 so that this can easily be known by a user from a visual inspection of the stabiliser. An edge 80 of the protrusion forms a second engagement surface while an edge 70 of shaft 7 forms the first engagement surface. While the second engagement surface will always be formed by edge 80, the edge which forms the first engagement surface will depend on which side of the stabiliser the pin is inserted.

Figure 4 shows the pins in position within the stabiliser 1, however the heads 9 have been omitted for clarity. Here one pin has been fitted within hole 17 with the protrusion 8 within cavity 17b such that the second engagement surface 80 is facing the stile receiving gap 20 while the other has been inserted with the protrusion in cavity 17a such that edge 70 and hence the first engagement surface is facing the stile receiving gap 20. The distance between these pins forms the stile receiving gap 20.

The positions of the pins can be altered to adjust the width of the stile receiving gap. This is shown in Figures 5A-B. Figure 5A shows both pins inserted with protrusion 8 in cavity 17a such that edges 70 are facing the stile receiving gap 20. This creates the largest gap and is used for ladders with stile widths between 65mm and 82mm. In Figure 5B the pins have been removed from holes 17, rotated in the direction of the arrows and reinserted with the protrusions 8 in cavity 17b. Therefore, edges 80 now face the stile receiving gap and the stabiliser is now suitable for use with stiles with a width of less than 65mm. The pin heads 9 are shaped to indicate the position of the protrusion 8 for ease of reference. The pins are also adjustable along their longitudinal axis by a sliding motion guided within holes 17. This allows the pins to be adjusted to account for stile thickness, see Figure 6. The effective length B of the pin shaft 7 protruding from the attachment portion 5 can be adjusted to be slightly longer, for example 1-2 mm longer, than the width of the stile edge 10, 11. The device is thereby securely

attached to the ladder but remains sufficiently loose to slide freely on the stile so that it can adjust itself on contact with the ground, wall or any solid surface whereupon the device is rotated slightly about an axis generally parallel to the rungs of the ladder. The positioning of the flattened heads 9 adjacent to the inside face of the ladder stile prevents the device from becoming detached by moving sideways away from the ladder stile. A recessed channel 12 on the inner face of the attachment portion 5 (see Figs 2 and 7) allows freedom of movement even where protrusions are present on the outer side face of the stile, such as rivets or the ends of the rungs . The preferred clamping mechanism is shown in Fig 2 and comprises a pad bolt 13 having a threaded region at one end 14 and a cut-away radius 15 of a diameter corresponding to the diameter of the pin shaft 7. The pad bolt 13 fits into a blind cylindrical bore 16 in the attachment portion 5 and the pin shaft 7 is then fitted into the perpendicular receiving hole 17. The pin is clamped into position by screwing a nut 18 and washer 19 onto the threaded region of the pad bolt which pulls the pad bolt in a direction generally perpendicular to the longitudinal axis of the pin and fastens the pin in position. Nut cover 21 provides an aesthetic and smoothed finish. Alternatively a wing nut could be used in place of nut 18.

Figures 7, 8 and 9 show a right-hand stabiliser in greater detail. In a preferred embodiment the stabiliser leg 4 is provided with webbing 28 to provide greater strength. It may be seen that the attachment

portion is formed generally as a hollow dome so that the face (visible in Fig. 2) which engages the outer side face of the ladder stile is free of material in a central circular region. Figure 10 shows a rubber foot 22 which connects to a suitably dovetail- and wedge-shaped plate 23 fixed to the lower end of leg 4.

It is unnecessary to release the device each time the ladder is moved: the device may remain attached to the ladder stile and simply readjusts itself when the ladder is repositioned. However after the pins have been adjusted to fit a particular stile width the stabiliser can be clipped onto and removed from the ladder in seconds without any adjustment. One pin is fitted over one end of the stile after which the other pin is pushed over the other end to attach the stabiliser. This process is reversed to remove the stabiliser. Because of this ease of attachment the device can be removed after use and only re-attached to the ladder once this has been correctly positioned.

This prevents the stabilisers interfering with correct ladder placement.

The adjustability of the device provides for simple fitting of a standard design of stabiliser to almost any size or shape of ladder.

Many modifications can be made to the device if desired: the leg portion may be tapered towards its free end if it is desired to fix it into soft ground. Alternatively, if it is preferred for the leg portion to rest on the surface of the ground, it may be thickened at its free end to provide a flat or serrated portion or pad, or an articulated foot could be provided.