GB2538852A

GB2538852A - A stabilising device

Info

Publication number: GB2538852A
Application number: GB1605819.0A
Authority: GB
Inventors: Akhtar Mubashir
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-04-09
Filing date: 2016-04-05
Publication date: 2016-11-30
Anticipated expiration: 2036-04-05
Also published as: GB2538852B; GB2537143B; GB2537143A; GB201506016D0

Abstract

A stabilising device 100 for a ladder, comprises a body 102, a leg member 104 coupled to the body, which can rotate about an axis 106 extending from the body, and a locking mechanism. The locking mechanism comprises first (110, Fig. 11) and second (112, Fig. 9) components, where the first component is moveable relative to the second component between two different positions, in a direction which is parallel to the axis. When the first blocking component is in the first position, the strut is free to rotate about the axis and when it is in the second position the locking elements are engaged to prevent rotation of the leg member about the axis. The device may comprise attachment means which may include a protruding element 118 for insertion into a hollow rung. A number of devices may be provided as a kit.

Description

A STABILISING DEVICE

Technical Field

The present invention relates to devices to stabilise devices, in particular to stabilising devices for ladders, more particularly but not exclusively stabilising legs attachable to a ladder in use.

Background

It is known to stabilise ladders against slipping, in particular on uneven, sloping or slippery ground. A variety of devices are known to achieve this, typically comprising a leg that is attachable to the ladder that will provide extra footing and friction against movement parallel to the ladder -i.e. the feet of the ladder slip backwards from the wall or building -or movement transverse to it -i.e. the ladder sways sideways.

11520120048647 discusses a system which allows for stabilizing a ladder on multiple surfaces without the need for a second person or a great deal of setup time. The collapsible ladder system includes a larger ladder section and a smaller ladder strut section which are pivotally connected at a point which is at or below the midpoint of the larger ladder section. The larger ladder section and smaller ladder strut section are connected by a rigid adjustable linkage, or spreader, at a point that is below the pivotable connection. The ladder further includes a means for stability on a variety of surfaces. At the ground contact point, the point where the ladder side rail ends and the ground meet, there are adjustable gripping feet, which can be independently or in combination vertically or angularly adjusted for maximum stability.

This device requires a permanent fixture to the ladder and needs modification -i.e. holes drilled in the side rails of the ladder to fix the device to the side rails, which means it is suitable only for inclusion at the manufacturing stage.

1JS20140131541 discusses a ladder safety device that can include one or more stabilizing legs configured to be removably or permanently attached to a ladder. An attachment mechanism of the ladder safety device removably attaches to the ladder through rung holes already present in the ladder. The stabilizing legs are preferably secured in the attachment mechanism such that they can be securely oriented at a desired angle extending away from the ladder legs and can be independently extended to have a desired length.

This device has legs that may be extended transversely from the ladder, but which do not extend in the direction parallel to the ladder. Therefore they only protect against transverse slippage of the ladder.

Summary

According to a first aspect of the present invention, there is provided a stabilising device for a ladder comprising: a body, a leg member coupled to the body for rotation about an axis extending from the body, and a locking mechanism. The locking mechanism comprises first and second locking components and the first locking component is movable relative to the second locking component in a direction substantially parallel to the axis between a first position and a second position. When the first locking component is in the first position, the leg member is free to rotate about the axis and when the first locking component is in the second position the first and second locking components are engaged to prevent rotation of the leg member about the axis.

Such a device provides additional stability to an upright item, such as a ladder, from slipping during use. The leg member is rotatable about the axis, this allows the leg member to be moved into a position where a free end is engaged with a surface, such as the ground in use. When the first locking component is in the second position, rotation of the leg member about its rotational axis cannot occur. This provides improved safety because the leg member is locked in position by the locking mechanism. The leg member is therefore locked in place and is no longer free to rotate.

The first and second locking components being "engaged" may also be referred to as the first and second locking components being mated, or interlocked.

The device of the present invention allows the user to easily adjust the rotational position of the leg member and then lock it in that position. For example, the locking mechanism can be easily operated to allow the user to rotate the leg member to a desired position engaged with the ground or other surface in use, and then lock the leg member in place.

Reference to "in a direction substantially parallel to the axis" includes moving in a direction along the axis as well as in a direction substantially parallel to the axis but offset from the axis. The movement of the first locking component in a direction substantially parallel to the axis provides a further benefit that the axis will generally be in a direction which experiences relatively small forces in use, enhancing safety because the ladder locking mechanism is less likely to become disengaged accidentally. An example ladder comprises two side rails substantially parallel to each other, and a plurality of rungs spanning between the side rails. The rungs are substantially perpendicular to each of the side rails and are therefore generally horizontal when the ladder is used on flat ground. In one example, the ladder has an upper and a lower end.

A ladder is placed with its upper end against a surface and its lower end against the ground. A stabilising device according to the invention is "in use" if it is attached to the ladder.

In some embodiments the first and second locking components are coaxial about the axis. Or in other embodiments one of the first and second locking components is coaxial with the axis. Such a configuration can allow the locking mechanism of the stabilising device to have a smaller profile making it less bulky.

In some embodiments when the first locking component is in the second position the relative distance between the first locking member and the body is smaller than when the first locking component is in the first position. This lowers the profile of the locking mechanism. A further advantage is obtained if the first locking component is attached to the leg member, in that case the torque applied to the body by the leg member is reduced. Torque will be minimised if the leg member is closer to the body during use (i.e. when in the locked configuration).

In some embodiments the axis extends from the body in a direction parallel to an axis defined by a ladder rung in use (i.e. the axis is perpendicular to an axis defined by the ladder rails). In this configuration, the leg member can rotate about the axis in a plane that is perpendicular to the axis defined by ladder rungs in use. Here reference to in use means that the body of the stabilising device is attached to a side rail of the ladder.

The leg member may be straight. A straight leg member may be beneficial for storage purposes by reducing the space taken up by the stabilising device, when the leg member is aligned with a side rail of a ladder.

The leg member may also be curved, bent or otherwise extend in the direction of the axis. For example, at least a portion of the leg member may extend in the direction of the axis. Such constructions can allow the leg member to provide transverse support to the ladder to prevent lateral motion of the ladder in use because the extension in the direction of the axis means that the free end of the leg member is offset from the side rail in use.

The axis may extend from the body at an angle, such that in use the axis is disposed at an acute angle to an axis defined by a rung of the ladder. Again, reference to in use here means that the stabilising device is attached to a side rail of the ladder.

This configuration allows an end of the leg member to splay outwards from a side rail when the free end of the leg member is close to the ground. This increases the footprint defined by area between the legs of ladder and leg members of two stabilising devices attached to the ladder when compared a stabilising device whose leg members only rotate in a plane perpendicular to the ladder rungs. This increased footprint, due to the angled axis, provides support against sideways or transverse forces. However, when the leg member is in a position for storage, parallel to a side rail of the ladder, the angled axis means that rather than the free end being positioned some distance from the side rail, the free end is positioned substantially flush with the side rail. A low storage profile for the stabilising device and a splayed profile for improved safety in use may both be achieved.

For example, when the ladder is placed on a flat surface, the rungs of the ladder are generally horizontal. In that case an angled axis means that the axis either points upwards away from the ground, downwards towards to the ground, towards a wall against which the ladder is resting, or away from a wall (or any combination of these directions). The angle is measured between the axis defined by a rung (or an axis parallel to a rung) and the axis extending from the body of the stabilising device about which the leg member rotates. It may be advantageous for the angled axis to point in a direction that would be generally towards a wall when in use.

In some embodiments the locking mechanism further comprises a retaining member configured to maintain the first locking component in the second position to prevent rotation of the leg member about the axis. The use of a retaining member allows the first and second members to be locked in the engaged position for safety purposes,

S

meaning that the leg member is not free to rotate. In some embodiments the retaining member is biased to maintain the first locking component in the second position. The retaining member may be a knob, a nut, or any other suitable means to prevent the first locking component from moving relative to the second locking component, so that they are retained engaged in the locked position.

In some embodiments the stabilising device further comprises a rod member that defines the axis, wherein the rod member extends through a through hole in the leg member, and the retaining member is attached to the rod member and is moveable along a length of the rod member. This can to allow the first locking component to be retained in the second position. The use of a rod member allows the leg member to rotate about the rod member. The retaining member may move along the rod member to stop the first locking member from moving relative to the second locking member in a direction parallel to the axis. In some embodiments one or both of the first and second locking components also comprise a through hole through which the rod member extends. Such a construction allows easy adjustment using the retaining member to allow the first and second locking components to be transitioned between engaged and disengaged positions.

In some embodiments the second locking component is attached to the body, the leg member comprises a recess and the first locking component is attached to the leg member within the recess. When the first locking component is in the second position, the second locking component is received in the recess. When the first and second locking components are contained within the recess when in the engaged configuration, the locking components are concealed and protected. The recess further allows the leg member to be locked in a position closer to the body reducing the torque exerted on the body by the leg member in use.

A projection may extend from the body and the second locking component may be mounted on the projection. The projection comprises a projection surface. In some embodiments the axis is perpendicular to a plane defined by the projection surface. In the embodiments where the axis is angled, the projection surface may also be angled, and the second locking component is also angled. The projection surface may provide a base on which to mount the second locking component and a surface to engage a portion of the leg member. This can enhance the overall stability of the device when the locking mechanism is locked.

In some embodiments, the first locking component comprises gear teeth and the second locking component comprises corresponding gear teeth. When the first locking component is in the second position, the gear teeth and corresponding gear teeth engage to prevent rotation of the leg member. The use of gear teeth provides an effective way to lock the first and second locking component in the second position. Furthermore, gear teeth allows the leg member to be rotated and secured in defined, discrete locations allowing a range of angular positions. The first and second locking components may therefore be gears. In one embodiment one of the locking components may be an internal gear with gear teeth on its inner circumference, the other locking component may be an external gear with teeth on its exterior circumference. The external gear fits within the internal gear and the corresponding gear teeth engage. In other embodiments only one of the first and second locking components is a gear, and the other component engages with one or more of the gear teeth to prevent rotation. While gear teeth are referred to, the first and second locking components may engage in other ways, for example, the first and/or second locking components may have a generally castellated form or have corresponding recesses and protrusions. In one embodiment the body comprises recesses, forming the second locking component, and the first locking component comprises one or more protrusions to engage the recesses and prevent the leg from rotating about the axis. In some embodiments the first and second locking components may be keyed elements that engage when first locking component is in the second position.

The stabilising device may be permanently or removably attached to a ladder, for example to a side rail of the ladder. Attachment means may be provided for attaching the device to the ladder. The device may be attached to abut a side rail of the ladder. The attachment means could comprise one or more nuts and bolts and/or one or more rivets. In other embodiments the attachment means may allow the device to be easily removed from the ladder when not in use.

In some embodiments the attachment means comprises a channel formed in the body, wherein the channel is configured to receive a side rail of the ladder in use. For example, the channel may comprise a channel floor and first and second channel walls.

The channel floor abuts the outer surface of the side rail, which is generally perpendicular to an axis defined by a ladder rung. The two channel walls, which are generally perpendicular to the channel floor, abut two side surfaces of the side rail. This channel helps reduce the likelihood of the stabilising device from sliding laterally when viewing the ladder side on. A channel may also reduce production costs as it is relatively easy to manufacture. The width ofthe channel (i.e. the distance between the two channel walls) is chosen to match the width of the ladder side rail. In some embodiments the stabilising device may be manufactured according to varying specifications to match varying width ladder rails. The channel walls may be positioned further apart than the side rail dimensions, for example lmm, 2mm, or 3mm further apart; in that case the channel provides additional stability to reduce relative movement between the body and the ladder. Alternatively the channel walls may be positioned substantially the same distance apart as the side rail dimension, to provide an element of friction fit in addition to increased stability.

In some embodiments, the attachment means comprises a side rail clamping mechanism. The side rail clamping mechanism may comprise first and second clamp members, and an adjustment means for adjusting a distance between the first and second clamp members. The first and second clamp members may have clamp surfaces and can be moved towards and away from each other to receive a portion of the ladder side rail between them. The adjustment means controls the movement of the first and second clamp members. Such a clamp mechanism is therefore adjustable for many different width ladder rails and can be adjusted to increase the grip with the ladder side rail. In some embodiments, the attachment means comprises a protruding device extending from the body. The protruding device may be configured to be received within a rung of a hollow rung ladder in use. The protruding device protrudes into the rung to help secure the stabilising device to the ladder. The protruding device helps reduce movement of the stabilising device from its attachment position. Furthermore, this construction provides a low profile attachment solution for hollow rung ladders. In some embodiments, the length of the protruding device is such that it extends into less than half of the distance of a rung of the ladder in use. In this way a stabilising device can be attached to each side rail of the ladder and the protruding devices from each stabilising device can be inserted into the same ladder rung. The protruding device may be a gripping device to grip the inside of the rung. In some embodiments the protruding device is tubular, such as a rod. The protruding device may be constructed from one or more sections, each of which could be made from different materials.

In some embodiments at least a portion of the protruding device is actuatable to increase a cross sectional dimension of the protruding device over at least a portion of its length. Increasing a cross sectional dimension of the protruding device (such as its diameter) can increase the grip within the rung to provide additional stability. Increasing the cross sectional dimension once the protruding device is inserted into a rung means that it can be easily inserted due to the relatively small diameter, then have its diameter increased to provide grip once inserted.

In some embodiments the protruding device is an expandable element configured to engage a hollow rung in use. At least a portion of the protruding device may be deformable.

In some embodiments the protruding device comprises a hollow cylindrical body extending from the body, a deformable hollow bung mounted around the outside of the cylindrical body and movable with respect to it, a nut connected to an end of the bung, a clearance hole extending through the body and aligned coaxially with the cylindrical member and a bung bolt arranged to pass through the clearance hole and the nut. In some embodiments the nut and the bung are rotatably fixed with respect to one another. In some embodiments the nut is connected to a distal end of the bung. This configuration allows the protruding device to be actuated to increase its cross sectional dimension to increase the grip inside the rung. By screwing the bung bolt, the nut is drawn towards the body which causes the hollow bung to deform. This expansion of the bung forces the bung to contact the inside of the rung increasing or providing grip.

In other embodiments the protruding device comprises a support member extending from the body and adapted to pass inside the rung, a nut free to slide within the support member but not to rotate with respect to the support member, a wing member pivoted to the support member and pivoted to the nut, a clearance hole extending through the body and aligned coaxially with the nut and a bung bolt arranged in use to pass through the clearance hole and the nut. In some embodiments the nut is a distal nut.

In some embodiments the body comprises a rotation stop configured to prevent rotation of the leg member beyond a first angle relative to the body in a clockwise direction and beyond a second angle relative to the body in an anticlockwise direction. In this way the rotation stop sets a maximum angular distance between the leg member and the upper portion of side rail of the ladder. Here, the upper portion of the side rail refers to the side rail above the point at which the stabilising device is attached to the ladder when the ladder is in the generally upright position against a wall. In other words, the angular separation between the leg member and the lower portion of the side rail must be greater than a defined angle. This is beneficial to provide adequate support to the ladder. To adapt the stabilising device for the opposite side rail, the leg member is rotated. The rotation stop therefore prevents rotation of the leg member beyond a second angle in the opposite direction which provides the same benefit when the stabilising device is used on the other side rail. In some embodiments the rotation stop is a protrusion extending from the body. It may comprise first and second surfaces to abut the leg member to limit or stop the rotation in each direction. In some embodiments the rotation stop is positioned below the axis.

In some embodiments a rotatable, or free, end of the leg member is rotatable about the axis to a substantially inverted position with respect to the ladder. Here "substantially inverted position" means that the end of the leg member that is usually in contact with the ground in use is rotated towards the upper portion of the side rail of the ladder. The leg member may therefore be considered to be upside down. This position is beneficial for storage purposes, allowing the leg member to be rotated upwards to minimise the space occupied during storage.

In embodiments where the rotation stop is positioned below the axis, the rotation stop would not allow the leg member to rotate beyond the first or second angles relative to the body. This means that the leg member must be stored in an upright/inverted position because the leg member cannot be rotated any further towards the lower portion of the side rail. The rotatable end of the leg member can therefore rotate between a position defined by the first angle, the substantially inverted position and a position defined by the second angle. The leg member may also be locked at other positions within this range. The substantially inverted position may be at a midpoint between the positions defined by the first and second angles. Such a construction allows the safety benefits of the rotation stop to be used without compromising the benefits of storage. In some embodiments the leg member is separable from the body. This may be useful for storage because the stabilising device can be dismantled.

In some embodiments a ladder is provided which comprises a stabilising device.

A ladder may be supported by one or more stabilising devices, for example two stabilising devices. A stabilising device may therefore be located on each side rail. The two stabilising devices may be identical. For example, the example stabilising devices described can be used on either side rail by rotating the leg member about the axis and rotating the body so that it can abut the opposite side rail. This means that the same stabilising devices can be used for each side rail, regardless of whether it is on a left or right side in use. This reduces manufacturing costs.

The locking mechanisms on each separate stabilising device can be individually operated so that each respective leg member can be locked in different angular positions. This may be desirable when the ladder is placed on uneven ground so that adequate support can be provided for the ladder. In other uses, the leg members can be locked at the same angular positions.

In some embodiments a ladder stabilising kit is provided which comprises two stabilising devices.

According to another embodiment there is provided a stabilising device for a ladder comprising two side rails joined by hollow tubular rungs, the device comprising: a clamp body having a first clamp surface and an opposed second clamp surface, the first surface adapted to mount adjacent to a side rail of the ladder; a clamp mechanism adapted to move first and second clamp surfaces to clamp the clamp body onto a portion of the side rail; a rung grip device extending from the clamp body adapted to be received within the interior of a tubular rung; and an elongate leg mounted at a first end onto the second clamp surface of the clamp body such that a second opposed end of the leg is rotatable about an axis extending substantially perpendicular to the second clamp surface.

In some embodiments the leg comprises a locking means operable to lock the leg at a chosen angular position with respect to the clamp. In some embodiments the locking means comprises the first and second locking components In some embodiments the leg is separable from the clamp In some embodiments the rung grip device comprises an actuation device adapted to expand within the rung to grip the internal surface of the rung. The rung grip device may be substantially the same as the protrusion device In some embodiments the clamp body comprises a leg rotation stop to control the range of angular rotation of the leg relative to the clamp body, such that in use the stop determines a minimum angle at which the leg may be set relative to the side rail.

In this way the rotation stop ensures a large enough angle relative to the side rail to provide an acceptable degree of stabilisation in use, such that the device comprises a safety means to prevent the leg from being set at too narrow an angle relative to the side rail when in use.

In some embodiments the apparatus comprises a first and a second device comprising a first and second assembly, each assembly comprising a clamp, a leg and a locking means, wherein the first (left) and second (right hand) assemblies are configured to mount on and to stabilise the first and the second side rails of the ladder.

In some embodiments the device is configured such that the leg is mountable in a first angular orientation with respect to the clamp body to adapt the device for use on the right side rail and a second angular orientation with respect to the clamp body to adapt the device for use on the left side rail.

In this way the device may be adapted to mount securely on a side rail of a ladder standing on the ground, with the rung grip device within the inside of a hollow tubular rung and actuated to grip the inside of the rung, and the first and second clamp faces on opposing sides of the side rail and clamped to the rail, the leg is mounted on the clamp and locked at a chosen angle such that the second end of the leg distal from the first is in contact with the ground to stabilise the ladder. A first and a second device may be used to stabilise both legs The variable angle of the leg with respect to the clamp, and hence with respect to the side rail allows the leg to stabilise the side rail at a chosen angle of the ladder with respect to the ground, and to compensate for variable height or slope of the ground.

The clamp mechanism may comprise a rotatable knob and a gear mechanism to connect rotation of the knob to movement of the clamp faces towards or away from each other, for example comprising a rotating gear connected to the knob and one or more linear racks attached to one or both clamp faces and engaging with the gear.

The rung grip device may comprise: a hollow cylindrical body extending from the first clamp surface of the clamp body, a deformable hollow bung mounted around the outside of the cylindrical body and movable with respect to it, a nut connected to the distal end of the bung such that the nut and the bung are rotatably fixed with respect to one another, a clearance hole extending through the clamp body and aligned coaxially with the cylindrical member, and a bung bolt arranged to pass through the clearance hole and the distal nut.

In this way, tightening of the bung bolt may cause the distal nut to be drawn towards the clamp body, so compressing the bung and causing it to expand outwards to grip the internal surface of the rung.

In some embodiments the rung grip comprises: a support member extending from the first clamp surface of the clamp body and adapted to pass inside the rung, a distal nut free to slide within the support member but not to rotate with respect to the support member, a wing member pivoted to the support member and pivoted to the distal nut, a clearance hole extending through the clamp body and aligned coaxially with the distal nut, and a bung bolt arranged in use to pass through the clearance hole and the distal nut.

In this way, tightening of the bung bolt causes the distal nut to be drawn towards the clamp body, so causing the wing to pivot with respect to the support member and causing it to expand outwards to grip the internal surface of the rung.

In some embodiments the locking means comprises a twist grip knob mounted fixedly on a screw thread, the leg comprises a clearance hole for the screw thread and the clamp body comprises a threaded hole provided on its second face to receive the In screw thread. In this way the screw thread may be passed through the clearance hole in the leg and into the threaded hole, tightening the screw thread using the twist grip knob then acting to clamp the leg to the second face of the clamp body. In some embodiments the second face comprises a substantially cylindrical projection arid the threaded hole is coaxial with the projection, and the first end of the leg comprises a substantially cylindrical recess to receive the projection. In this way in use the leg may be located correctly with respect to the clamp body and force on the leg parallel to the clamp body may be taken in use by contact between the projection and the inner wall of the recess. In some embodiments the projection and the recess may comprise one or more stepped profiles around their circumference. The stepped profiles may act to provide friction against rotary movement of the leg relative to the clamp body. The stepped profiles may be configured such that the leg may move axially relative to the clamp body between a first, outward position in which the leg is free to rotate relative to the clamp body and a second, inward position adjacent to the second surface of the clamp body in which the stepped profiles engage to prevent rotation of the leg relative to the clamp body. In this way the leg may be fitted to the clamp body, rotated to the correct angular position, and then moved towards the clamp body to hold it in place against rotation. The twist grip knob may then be tightened to lock the leg in place.

In some embodiments the device comprises a foot articulated to the second end of the leg.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

Brief Description of the Drawings

Figure 1 shows an isometric embodiment of two devices according to a first embodiment of the invention in place on each side rail of a ladder.

Figure 2 shows an isometric view of the two devices as shown in figure 1 Figure 3 shows a front elevation of a device according to the first embodiment of the invention.

Figure 4 shows an exploded view of the device shown in figure 3.

Figure 5 shows an exploded view of the device according to the first embodiment ready to mount onto the rung and side rail of a ladder.

Figure 6 shows an exploded view of the clamp body of a device according to the first embodiment of the invention Figure 7 shows a side elevation of a device according to another embodiment of the invention.

Figure 8 shows perspective view of a leg member and body of the device of Figure 7.

Figure 9 shows a perspective view of part of the device according to the embodiment of Figure 7.

Figure 10 shows a side view of a leg member and body of the device of Figure 7, with the leg member in a generally downward position relative to the body.

Figure 11 shows a plan view of a part of the leg member according to the embodiment of Figure 7.

Detailed Description

Referring to figures 1 to 6, a first embodiment 10 of the invention comprises: A clamp 12 to configured to mount on a side rail 14, 16 of a ladder 18 having two side rails joined by hollow tubular rungs 20, the clamp comprising: A clamp body 22 having a first surface 24 adapted to mount adjacent to the side rail when the clamp is in position on the side rail and an opposing second surface 26, A first 28 and second 30 clamp faces slidably mounted on the first surface of the clamp body and movable towards and away from each other to receive a portion of the side rail between them, A clamp mechanism 32 mounted on the clamp body adapted to move the first and second clamp faces towards and away from each other to clamp onto the side rail, and A rung grip device 34 adapted to pass into the interior of a tubular rung 20, the rung grip device being mounted on the first surface 24 of the clamp body and extending from it, the rung grip device comprising an actuation device adapted to expand within the rung to grip the internal surface of the rung, and An elongated leg 40 mounted at its first end 42 on the second surface 26 of the clamp body and rotatable about an axis 44 substantially perpendicular to the second surface, and A locking means 46 operable to lock the leg at a chosen angular position with respect to the clamp.

In this embodiment the leg 40 is separable from the clamp 12.

In this embodiment the clamp body 22 comprises a leg rotation stop 48 to control the range of angular rotation of the leg relative to the clamp body, such that in use the stop determines a minimum angle at which the leg may be set relative to the side rail. In this way the rotation stop ensures a large enough angle relative to the side rail to provide an acceptable degree of stabilisation in use, such that the device comprises a safety means to prevent the leg from being set at too narrow an angle relative to the side rail when in use.

In this embodiment the device is configured such that the leg may be mounted in a first angular orientation with respect to the clamp body to adapt the device for use on the right side rail and a second angular orientation with respect to the clamp body to adapt the device for use on the left side rail. The clamp body comprises a first leg rotation stop 48, to control the range of angular rotation of the leg relative to the clamp body when in use on the right hand rail 14 and a second leg rotation stop 50, to control the range of angular rotation of the leg relative to the clamp body when in use on the left hand rail 16.

In this way the device is adapted to mount securely on a side rail of a ladder standing on the ground, with the rung grip device within the inside of a hollow tubular rung and actuated to grip the inside of the rung, and the first and second clamp faces on opposing sides of the side rail and clamped to the rail, the leg is mounted on the clamp and locked at a chosen angle such that the second end of the leg distal from the first is in contact with the ground to stabilise the ladder. A left and a right hand device may be used to stabilise both legs The variable angle of the leg with respect to the clamp, and hence with respect to the side rail allows the leg to stabilise the side rail at a chosen angle of the ladder with respect to the ground, and to compensate for variable height or slope of the ground.

The clamp mechanism 32 comprises a rotatable knob 52 and a gear mechanism 54 to connect rotation of the knob to movement of the clamp faces 28, 30 towards or away from each other, for example comprising a rotating gear connected to the knob and one or more linear racks attached to one or both clamp faces and engaging with the gear.

The rung grip device 34 comprises: a hollow cylindrical body 60 extending from the first face 24 of the clamp body, a deformable hollow bung 62 mounted around the outside of the cylindrical body and movable with respect to it, a nut 64 connected to the distal end of the bung such that the nut and the bung may not rotate with respect to one another, a clearance hole 66 through the clamp body coaxial with the cylindrical member, and a bung bolt 68 passing through the clearance hole and the distal nut.

In this way, tightening of the bung bolt 68 causes the nut 64 to be drawn towards the clamp body, so compressing the bung 62 and causing it to expand outwards to grip the internal surface of the rung.

In this embodiment the locking means 46 comprises a twist grip knob 70 mounted fixedly on a screw thread 72, the leg 40 comprises a clearance hole 74 for the screw thread and the clamp body comprises a threaded hole 66 (also the clearance hole for the bung bolt 68) provided on its second face to receive the screw thread. In this way the screw thread may be passed through the clearance hole 74 in the leg and into the threaded hole 66, tightening the screw thread using the twist grip knob then acting to clamp the leg to the second face of the clamp body. In this embodiment the second face 26 of the clamp body comprises a substantially cylindrical projection 76 and the threaded hole is coaxial with the projection, and the first end 42 of the leg comprises a substantially cylindrical recess to receive the projection 76. In this way in use the leg may be located correctly with respect to the clamp body and force on the leg parallel to the clamp body may be taken in use by contact between the projection and the inner wall of the recess. In this embodiment the projection 76 and the recess comprise a stepped profile 78 around their circumference. The stepped profiles acts to provide friction against rotary movement of the leg relative to the clamp body. In some variants of the embodiment the stepped profile may be configured such that the leg may move axially relative to the clamp body between a first, outward position in which the leg is free to rotate relative to the clamp body and a second, inward position adjacent to the second surface of the clamp body in which the stepped profiles engage to prevent rotation of the leg relative to the clamp body. In this way the leg may be fitted to the clamp body, rotated to the correct angular position, and then moved towards the clamp body to hold it in place against rotation. The twist grip knob may then be tightened to lock the leg in place.

In this embodiment the device comprises a foot 80 articulated to the second end 82 of the leg. In other embodiments the foot 80 may be omitted.

It is an advantage of the device that the leg 40 may be moved to a position parallel to, and pointing in the direction upwards alongside, the side rail, and locked in place so that the ladder may be stored with the device in place.

A stabilising device 100 according to another embodiment is shown in Figure 7. The stabilising device 100 comprises a body 102, a leg member 104 coupled to the body 102 for rotation about an axis 106 extending from the body 102, and a locking mechanism 108. The locking mechanism may be substantially similar to the locking means described earlier with reference to Figures 1 to 6. This device is for releasable attachment to a ladder and includes a protruding device 118 to engage a hollow rung of a ladder in use. The body also defines a channel (described in more detail with reference to Figure 8 below) having channel walls 132, 134 to engage a side rail of a ladder. The channel helps to prevent rotation of the device about an axis of the protruding device in use Also visible in Figure 7 is a retaining member 126.

The construction and operation will now be described further with reference to Figures 8, 9, 10 and 11 that show parts of the embodiment of Figure 7 to assist understanding.

Referring now to Figures 9 and 11, the locking mechanism comprises first locking component (see Figure 11) attached to or integral with the leg member 104, comprising an internal gear 110. The locking mechanism also comprises a second locking component 112 (see Figure 9). The second locking component 112 is an external gear, attached to the body 102. The first locking component 110 is movable relative to the second locking component 112 in a direction substantially parallel to the axis 106, between a first position and a second position. For example, in this embodiment the first position is further along the axis 106 in the direction away from the body 102 than the second position. When the first locking component 110 is in the first position, the leg member 104 is free to rotate about the axis 106 and, when the first locking component 110 is in the second position the first and second locking components 110, 112 are engaged to prevent rotation of the leg member 104 about the axis 106.

Axis 106 extends from the body 102 at an angle 114 (shown in Figures 9 and 10). In use, the axis 106 is disposed at an acute angle 114 to an axis 116. The axis 116 is defined in use by a rung of the ladder which receives the protruding device 118.

Figure 10 shows the axis 116 defined by a rung which receives the protruding device 118 and an axis 116' parallel to axis 116, which intersects axis 106 at a point on the body 102. Figure 10 shows the acute angle 114' with respect to axis 116', which is the same as angle 114 shown in Figure 9.

The axis 106 is disposed at an acute angle 114 to an axis defined by a rung of the ladder, so that an end 120 of the leg member 104 rotates away from the side rail of the ladder when close to the ground. (End 120 may also be referred to as a free end or a rotatable end.) Therefore an offset distance between the body 102 and the end UO of the leg member 104 along the axis 116 varies during the rotation of the leg member 104. This means that the leg member splays outwards, providing lateral (or transverse) support to the ladder as well as parallel support when the leg member 104 contacts the ground in use. As depicted in Figure 10, an offset distance 119 is present between the body 102 and the leg member 104 when the leg member is positioned in a generally downward position in use.

Referring again to Figure 9, the stabilising device comprises a threaded rod member 122 that defines the axis 106. The leg member 104 comprises a through hole 124 shown in Figure 10, and the rod member 122 extends through the through hole 124. The leg member 104 rotates about the rod member 122 when the first and second locking components are disengaged or in the first position.

Referring now to Figure 7, a retaining member or knob 126 is attached to an end of the rod member 122. The knob 126 has a threaded recess to receive the threads of the rod member 122. To adjust the position of the leg member 104 about its rotational plane, or to lock the leg member 104 in a desired position, the knob 126 can be moved. A user may rotate the knob 126 along the thread in a direction along the rod member 122 towards the body 102 of the stabilising device 100. The first locking member 110 may be moved towards the second locking component 112 into the second position where they become engaged. The knob 126 then secures the locking components in these positions and the leg member 104 is no longer free to rotate.

Rotating the knob 126 in the other direction moves the knob 126 in a direction away from the body 102 along the rod member 122. The leg member 104 and/or the first locking member 110 can then be moved in a direction parallel to the rod member, away from the body 102 and into the first position such that the first and second locking components 110, 112 are disengaged, which allows the leg member 104 to be rotated about the axis 106 to a new position.

The first and second locking components are coaxial about the axis 106 and comprise through holes, the rod member 122 extends through both through holes. The first and second locking components are located between the body 102 and the leg member 104. In this embodiment, the second locking component 112 is attached to the body 102 as shown in Figure 9 and the first locking component is attached to the leg member 104 within a recess in its inner surface. Therefore when the first and second locking components are engaged, the second locking component is also received within the recess. Because the first and second locking components 110, 112 are received within a recess of the leg member 104, the components 110, 112 are not exposed. Figure 7 depicts the device with the first and second locking components in the second position, concealed within a recess in a leg member and therefore the first and second locking components cannot be seen.

As can be seen most clearly in Figure 9, the second locking component 112 is mounted on a projection 127. The projection 127 may also be received within the recess of the leg member 104. A surface of the projection 127 is perpendicular to axis 106 and is therefore also angled relative to the axis 116. A planar surface 125 defined by the second locking component 112 is also perpendicular to axis 106 and therefore angled relative to axis 116.

First and second locking components 110, 112 are gears comprising gear teeth. The gear teeth interlock when the first and second locking components are engaged to prevent rotation of the leg member 104. The first locking component 110 is an internal gear, the second locking component 112 is an external gear, such that the exterior gear teeth of the second locking component 112 interlock with the corresponding internal gear teeth of the first locking component 110 when the second locking component 112 is received within the inner circumference of the first locking component 110.

The stabilising device 100 comprises attachment means for attaching the device 100 to a ladder, which comprise a combination of a channel 128 to engage a side rail of a ladder and a protrusion 118 to engage a hollow rung of the ladder. As can be seen in Figure 8, a channel 128 is formed in the body 102 which is configured to receive a side rail of the ladder in use. In this embodiment, the channel comprises a channel floor 130 and first and second channel walls 132, 134. The channel floor 130 abuts the outer surface of the side rail in use, which is generally perpendicular to the axis 116 defined by a ladder rung. The two channel walls 132, 134, which are generally perpendicular to the channel floor 130, are positioned to generally abut respective side surfaces of the side rail. This channel 128 helps secure the device 100 in place.

The protnading device 118 extends from the body and is configured to be received within a rung of the ladder in use. This protruding device may be substantially the same as the rung grip device 34 described above.

In other embodiments, a clamp may also be used as well as, or instead of the channel 128 to attach the device 100 to the ladder. For example the clamp may comprise a clamp body 22 and a clamp mechanism 32 as described above.

A clamp, channel and protruding device may be also be used in any combination as an attachment means in other embodiments.

The device 100 also comprises a rotation stop substantially similar to the leg rotation stop 48 described above to limit the range of angular rotation of the leg member 104 relative to the body 102. For example Figure 8 shows the leg member 104 that has been rotated through an angle 140 relative to the body. The rotation stop (obscured from view in Figure 8), prevents the leg member 104 from rotating beyond a first angle relative to the body. This ensures that a minimum angular separation is set between the leg member 104 and the lower portion of the ladder side rail.

The leg rotation stop is positioned below the axis. To move the leg member into a storage position from the position depicted in Figure 8, the leg member 104 is rotated in the direction of the arrow A until the axis 136 defined by the leg member is substantially aligned with the axis 138 defined by the body, such that the angle 140 is zero degrees. The axis 138 may be generally parallel to an axis of a side rail when the stabilising device is attached to a ladder. This constmction is beneficial so that a ladder with one or more devices 100 attached can be easily stored.

The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of invention. Firstly it will be understood that any features described in relation to any particular embodiment may be featured in combinations with other embodiments. Furthermore features described in relation to any particular embodiment may be identical or substantially similar to features of other embodiments. With respect to the specification therefore, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention, with variation and implementation obvious and clear on the basis of either common general knowledge or of expert knowledge in the field concerned. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as set out in the accompanying claims.

Claims

CLAIMS1. A stabilising device for a ladder, the stabilising device comprising: a body; a leg member coupled to the body for rotation about an axis extending from the body; and a locking mechanism comprising first and second locking components, the first locking component movable relative to the second locking component in a direction substantially parallel to the axis, between a first position and a second position; wherein, when the first locking component is in the first position, the leg member is free to rotate about the axis and, when the first locking component is in the second position, the first and second locking components are engaged to prevent rotation of the leg member about the axis.
2 A stabilising device according to claim 1, wherein the first and second locking components are coaxial about the axis
3. A stabilising device according to claim 1 or 2, wherein the axis extends from the body at an angle, such that in use the axis is disposed at an acute angle to an axis defined by a rung of the ladder.
4. A stabilising device according to claim 1, 2 or 3, wherein the locking mechanism further comprises a retaining member configured to maintain the first locking component in the second position.
5. A stabilising device according to claim 4, further comprising a rod member that defines the axis, wherein the rod member extends through a through hole in the leg member, and the retaining member is attached to the rod member and is moveable along a length of the rod member. 2.3A stabilising device according to any one of claims 1-5, wherein: the second locking component is attached to the body; the leg member comprises a recess and the first locking component is attached to the leg member within the recess; and when the first locking component is in the second position, the second locking component is received in the recess.A stabilising device according to any one of claims 1-6, wherein: the first locking component comprises gear teeth and the second locking component comprises corresponding gear teeth; and when the first locking component is in the second position, the gear teeth and corresponding gear teeth engage to prevent rotation of the leg member.8. A stabilising device according to any one of claims 1-7, comprising attachment means for attaching the device to the ladder.9 A stabilising device according to claim 8, wherein the attachment means comprises a channel formed in the body, wherein the channel is configured to receive a side rail of the ladder in use.10. A stabilising device according to any one of claims 8 to 9, wherein the attachment means comprises a side rail clamping mechanism, the side rail clamping mechanism comprising first and second clamp members and an adjustment means for adjusting a distance between the first and second clamp members.1 1. A stabilising device according to any one of claims 8 to 10, wherein the attachment means comprises a protruding device extending from the body, the protruding device being configured to be received within a rung of the ladder in use.12. A stabilising device according to claim 11 wherein at least a portion of the protruding device is actuatable to increase a cross sectional dimension of the protruding device over at least a portion of its length.13. A stabilising device according to claim 11 or 12, wherein the protruding device comprises: a hollow cylindrical body extending from the body; a deformable hollow bung mounted around the outside of the cylindrical body and movable with respect to it; a nut connected to an end of the bung, a clearance hole extending through the body and aligned coaxially with the cylindrical member; and a bung bolt arranged to pass through the clearance hole and the nut.14. A stabilising device according to claim 11 or 12, wherein the protruding device comprises: a support member extending from the body and adapted to pass inside the rung, a nut free to slide within the support member but not to rotate with respect to the support member, a wing member pivoted to the support member and pivoted to the nut, a clearance hole extending through the body and aligned coaxially with the nut, and a bung bolt arranged in use to pass through the clearance hole and the nut.15. A stabilising device according to any one of claims 1-14, wherein the body comprises a rotation stop configured to prevent rotation of the leg member beyond a first angle relative to the body in a clockwise direction and beyond a second angle relative to the body in an anticlockwise direction.16. A stabilising device according to claim 15, wherein the rotation stop is positioned below the axis in use.17 A stabilising device according to any one of claims 1-16, wherein, in use, the leg member is rotatable about the axis to a substantially inverted position with respect to the ladder.18. A stabilising device according to any one of the claims 1-17, wherein the leg member is separable from the body.19. A ladder comprising a stabilising device according to claims 1-18.20. A ladder stabilising kit comprising two stabilising devices according to any one of claims 1-18.21. A stabilising device substantially as hereinbefore described, with reference to figures 1-6 of the accompanying drawings.22. A stabilising device substantially as hereinbefore described, with reference to figures 7-11 of the accompanying drawings.