GB2427431A

GB2427431A - Ladder stabiliser accessory

Info

Publication number: GB2427431A
Application number: GB0512661A
Authority: GB
Inventors: Martin Pettit
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-06-22
Filing date: 2005-06-22
Publication date: 2006-12-27
Also published as: GB0512661D0

Abstract

An accessory for a ladder comprises a first arm 9 and a second arm 10, the first arm 9 being mounted by a first pivot 13 at one end to a first attachment means 11, the second arm 10 being mounted by a second pivot 15 at one end to a second attachment means 12, the other end of the first arm being connected by a third pivot 15 to the other end of the second arm, the attachment means 11, 12 being adapted for mounting to eg a stile 3 of a ladder, the pivotal mounting of the first arm and the second arm to its respective attachment means including a releasable fastening 23-26 enabling the respective arm to be locked to its respective attachment means at a desired angle. The accessory can act as a stay, stand-off or extension to a ladder stile at the top or the bottom.

Description

LADDERS AND LADDER ACCESSORIES

Field of the Invention The invention relates to ladders and to accessories adapted to be fitted to ladders, for example to ensure stability, accessibility and safety. Background to the Invention Ladders have been known for many years and are an invaluable means of reaching otherwise inaccessible positions, such as on or in buildings and in relation to other structures. The "standard" ladder is extremely versatile but various specific types have been developed for specific purposes. Some are articulated for use on staircases, for example. Others have one or more extensions to permit access to higher locations. However, all designs suffer from one serious drawback, namely that of stability when in use. Some ladders are designed with rubber feet to prevent slippage. Others are wider at the base than at the top in order to reduce the risk of sideways movement. In more recent designs, stays or stand-offs of one kind or another have been provided. These are intended to be fixed, permanently or temporarily, to a ladder so as to rest against a vertical surface against which the ladder is to be used. These can enable a ladder to pass over an obstruction and/or can steady a ladder where access is awkward. There are nevertheless many occasions when a ladder fitted with such a stay or stand-off is still not usable with any real sense of stability, security, comfort and reliability. The present invention therefore aims to overcome these difficulties.

Summary of the Invention According to the invention, an accessory for a ladder comprises a first arm and a second arm, the first arm being mounted by a first pivot at one end to a first attachment means, the second arm being mounted by a second pivot at one end to a second attachment means, the other end of the first arm being connected by a third pivot to the other end of the second arm, the attachment means being adapted for mounting to a ladder, the pivotal mounting of the first arm and the second arm to its respective attachment means including a releas- able fastening enabling the respective arm to be locked to its respective attachment means at a desired angle. The pivotal mountings are preferably arranged to permit rotation through at least 180 degrees. The first and second attachment means may be adapted to be releasably fastened to a ladder. Alternatively, the accessory may be permanently attached to a ladder. The attachment means are preferably adapted to be clamped at a selected location to a stile of a ladder. The third pivot may be variable in position along one or both said first and second arms. It may comprise a pivot pin adapted to be fitted into a selected hole of a series of holes provided along at least part of the length of one or both of the first arm and the second arm. The first attachment means preferably comprises a first portion pivotally connected to a second portion, the first portion adapted to be mounted to the ladder and the second portion adapted to be pivotally connected to the first arm. Similarly, the second attachment means preferably comprises a first portion pivotally connected to a second portion, the first portion adapted to be mounted to the ladder and the second portion adapted to be pivotally connected to the second arm. Conveniently, the first and second portions of each respective attachment means are pivotally connected by a pivot pin. Each first portion and second portion may have inter-fitting castellations provided with a through bore adapted to receive a respective pivot pin. A gap is preferably provided between adjacent castellations of a respective first and second portion, and a spring is located in the gap arranged to bias abutting surfaces of the castellations into engagement with one another. A lever with over-centre action may be provided so that, when in an operative position, the abutting surfaces are forced into engagement with one another. The abutting surfaces of the castellations may be provided with serrated or ribbed portions, whereby relative pivotal movement is prevented when the lever is in the operative position. Alternatively, the first and second portions of each respective attachment means may be pivotally connected by a bolt or similar fastening, which can be tightened when the first and second portions are in a desired disposition, whereby to prevent undesired relative movement. The invention also provides a ladder provided with at least one accessory according to any of the preceding paragraphs. A said accessory may be deployed to the side of the ladder. A said accessory may be deployed in a direction out of the plane of the ladder. A said accessory may be deployed in line with a stile of the ladder to act as an extension to the stile. The ladder may be provided with at least one accessory that is permanently attached to it. Brief Description of the Drawings The invention will now be described with reference to the following drawings, in which: Figure 1 is a general representation of a ladder fitted with four accessories according to the invention; Figure 2 is a more detailed representation of an accessory according to the invention; Figure 3, 4 and 5 represent various optional dispositions of the accessory; Figure 6 illustrates a combination of dispositions and orientations of a number of accessories in a particular exemplary situation; Figure 7 is a side view of another disposition; Figure 8 is a perspective view of a further configuration; and Figure 9 is a front elevation of yet another configuration. Detailed Description of the Illustrated Embodiments First, a general outline of the accessory in a variety of typical situations will be described in outline by way of introduction to the versatility of the invention. Figure 1 shows a typical ladder 1 having parallel stiles 2, 3 (preferably fitted with rubber or other "non-slip" ends) and a plurality of rungs 4. The rungs may be of any cross-sectional shape and do not affect the present invention. Four accessories 5-8 in accordance with the invention are represented generically at the top and bottom of the ladder. In this particular configuration, the two top accessories 5, 6 can be deployed as steadies or stand-offs. These would be spread out to the sides so as to contact a vertical (say) surface against which the ladder is being used.However, it is not necessary for the ladder itself to contact the surface at all: this can all be done by the accessories, as will become clear later. Two accessories 7, 8 at the bottom can be deployed for stability. They will likewise be spread sideways and can contact the ground or other horizontal surface to improve stability and security for the user. They may be spread into the same plane as the ladder or can form a multi-point contact with the ground to provide stability in different directions. Bottom accessories could be deployed to contact the ground at points nearer the upright surface that the ladder is intended to reach. In this way the ladder can be placed near the surface but it does not need to make physical contact with it at all. Turning now to Figure 2, one embodiment of an accessory in accordance with the invention consists of a pair of arms 9, 10 and a pair of mounting connections 11, 12. One arm 9 is pivoted at 13 to a first one of the connections 11 and the second arm 10 is likewise pivoted at 14 to the other connection 12. The two arms 9, 10 are pivoted to one another at 15. The arms 9, 10 may be of equal length but are preferably unequal to enable the accessory to cope with different situations. The arm 9 may be around one metre in length whereas the shorter arm 10 may be around 800mm, for example. Both arms are preferably of cast aluminium for strength and lightness but other materials may be used instead. The longer arm 9 is preferably fitted with a rubber or other grip 16 to prevent slipping on a smooth surface. Each mounting connection is substantially the same, so only one will be described in detail. Figure 2 includes an inset on an enlarged scale to assist the description. Each connection has a mounting portion 17 adapted to be fitted to a stile of a ladder shown in phantom at 3 in Figure 2. The fitting may take any convenient form, such as a clamping device, whose detail is not shown since there are a large number of possible connections available to the skilled person. However, since the accessory is intended for rapid deployment on site, it would be preferable for the fixing to be simple and to permit easy attachment and removal as well as adjustment along the length of a stile once in the generally required position. Some form of U-clamp with a securing bolt or an overcentre mechanism with gripping surfaces would be satisfactory.Alternatively, the accessory can be fitted permanently to a ladder at the stage of manufacture of the ladder. The mounting portion 17 is formed with castellations 18, 19 that interfit with complementary castellations 20, 21 on a second portion 22. The castellations are each formed with a through hole to receive a pivot pin 23, which thereby connects the two portions 17, 22 together but allows relative pivotal movement. One end of the pin is formed with a head 24 to prevent its removal. The other end is formed with a shaped section 25 for co-operation with an overcentre action lever 26. In a gap between the castellations 19, 20 is located a spring 27. The mating surfaces of castellations 19, 21 and 18, 20 are formed with corrugations, serrations or the like, radial or otherwise, so that when they are pushed together, the two portions 17, 22 cannot rotate about the axis of the pin 23. In operation, the portion 22 can be swung around the axis of the pin 23 until the corresponding arm 9 or 10 is in the correct position for suitable deployment against a wall or the ground, for example. The overcentre action lever 26 is then lifted over a neutral position until the spring 27 snaps the castellations together and the serrated formations inter-engage, thereby locking the attachment device in its selected position. Of course, other methods may be used for securing the two portions 17, 22 in their chosen position. For example, the pin 23 may be replaced by a bolt that can simply be tightened to fix the portions together. If desired, a ratchet and cam mechanism may be added to prevent movement in an undesirable direction when the accessories have been deployed and are in use. Instead of a fixed position for the pivot 15, the arms 9, 10 may be provided with a plurality of holes designed to receive a removable pivot pin ena- bling the arms 9, 10 to be pivoted to one another at a variety of relative positions. This option will add even more versatility to the accessory of the invention. Taking into account the pivots pins and the other pivots 13, 14 and 15 described earlier, and the fact that the two attachment devices 11, 12 may be located anywhere along a ladder stile, each accessory provides at least 7 degrees of freedom, enabling an accessory to be deployed in a wide range of applications. Some examples of conventional and extreme situations will now be described. In Figure 3, the upper end of a ladder 30 is shown with a pair of accessories 31, 32 extended outwardly to act as a stand-off against a wall shown schematically by the broken line 33. Alternatively, the Figure could be inverted to represent the base of a ladder with the accessories acting as extensions to elevate the ladder beyond its natural extent. In Figure 4, one accessory 41 attached to the upper end of a ladder 40 is deployed in the same way as for Figure 3 but the other 42 is disposed out to one side. The ladder can then be safely used against a wall having parts 43 and 44 that are not in the same plane as one another. Figure 5 is similar to the arrangement in Figure 3 except that the arms 51, 52 are splayed out more to the sides so as to bring the upper end of the ladder 50 closer to the surface 53. Figure 6 illustrates a more complex situation. Here, the ladder 60 is provided with four accessories. The first, 61, is deployed as a stand-off so as to rest against a first wall portion 63. The second accessory, 62, is deployed as another stand-off to the opposite side of the ladder and rests against another wall portion 64. The second accessory is used to avoid an obstruction, such as a window 65, which would otherwise prevent the ladder itself from resting against the wall portion 64. It is to be noted that the wall portions 63, 64 are not co-planar, such as when the building of which they form part has an extension.Figure 6 represents that scenario and shows how accessory 62 can be deployed more to the side than accessory 61, since the latter has a greater gap to cover between the ladder 60 and its neighbouring wall portion 63. At the foot of the ladder, accessory 66 is deployed as an extension to raise the base of the right hand stile (as viewed in Figure 6) above ground level 67. The other bottom accessory 68 is splayed out to the side to rest on a step, which may be part of a flight of stairs 69 or simply a change in ground level. The ladder 60 can safely be used in the position illustrated. Finally, in Figure 7, a ladder 70 is in use against a building having an upper storey that does not extend outwardly as much as the lower storey. Upper accessory 71 rests against the wall 72 of the upper storey, enabling the ladder to avoid contact with an obstruction, such as window 73. In practice, there are likely to be two upper accessories 71. The lower end of the ladder 70 is fitted with one or more accessories 74. In the illustrated scenario, the ground at 75 may be hard enough for the ladder to stand but it stops too short from the building. The feet of the ladder would not then be able to rest on the ground at 75 and the upper end of the ladder to reach the wall 72 of the upper storey.Just to add to the difficulties facing the user of the ladder in this hypothetical but not unusual scenario, the ground level at 76 may be lower than that at 75 and may be too soft to rest the feet of the ladder. Although blocks or boards could be used to support the ladder's feet, they would still rest on the soft ground. It is even conceivable that the "ground" level at 76 is in fact a pond or the like, where resting the ladder's feet would be impossible. Instead, the bottom accessories 74 can act as the feet of the ladder in such a way that they rest on the hard ground at 75. In this way, the feet of the ladder are not actually touching the ground at all. The accessory of the invention may be employed to join two conventional ladders together in the form of a stepladder, as shown in Figure 8. The ladders 80 and 81 are joined at their heads by means of a first of the accessories 82, with a further two, 83 and 84, serving as stabilising supports as hereinbefore described. A fourth accessory 85 serves as a bracing strut between the two ladders 80 and 81. Since the accessories 82 and 85 are pivoted, the arrangement can be folded in the manner of a stepladder to permit it to be moved. Figure 9 illustrates yet another application for the accessories of the invention, where two ladders 90 and 91 are being used side-by-side for tandem working. By joining the ladders together near to the top and to the bottom with the accessories 92 and 93, the use of the ladders is made substantially safer and more secure. Although the invention has been described solely in terms of accessories for attachment to ladders, it is equally possible for them to be attached to other structures, such as scaffolding, scaffold towers, and staging etc. It should therefore be noted that the term "ladder" as used in the description and claims is intended to include such structures. Particular applications and uses of the invention have been described above but it should be clear that the permutations are virtually endless. The invention is universally attachable to virtually all manner of ladders etc and does not require any adaptation of an existing ladder at all. There is therefore no longer any need for articulated ladders or ladders of other unusual construction, to enable them to be used in non-conventional situations: the accessories of the present invention can provide all the versatility that is required under virtually all circumstances.

Claims

1. An accessory for a ladder, comprising a first arm and a second arm, the first arm being mounted by a first pivot at one end to a first attachment means, the second arm being mounted by a second pivot at one end to a second attachment means, the other end of the first arm being connected by a third pivot to the other end of the second arm, the attachment means being adapted for mounting to a ladder, the pivotal mounting of the first arm and the second arm to its respective attachment means including a releasable fastening enabling the respective arm to be locked to its respective attachment means at a desired angle.

2. An accessory as claimed in Claim 1, wherein the first and second attachment means are adapted to be releasably fastened to a ladder.

3. An accessory as claimed in Claim 2, wherein the attachment means are adapted to be clamped at a selected location to a stile of a ladder.

4. An accessory as claimed in Claim 1, wherein the third pivot is variable in position along one or both said first and second arms.

5. An accessory as claimed in Claim 5, wherein the third pivot comprises a pivot pin adapted to be fitted into a selected hole of a series of holes provided along at least part of the length of one or both of the first arm and the second arm.

6. An accessory as claimed in any preceding claim, wherein the first attachment means comprises a first portion pivotally connected to a second portion, the first portion adapted to be mounted to the ladder and the second portion adapted to be pivotally connected to the first arm.

7. An accessory as claimed in any preceding claim, wherein the second attachment means comprises a first portion pivotally connected to a second portion, the first portion adapted to be mounted to the ladder and the second portion adapted to be pivotally connected to the second arm.

8. An accessory as claimed in Claim 6 or Claim 7, wherein the first and second portions of each respective attachment means are pivotally connected by a pivot pin.

9. An accessory as claimed in Claim 8, wherein each first portion and second portion have inter-fitting castellations provided with a through bore adapted to receive a respective pivot pin.

10. An accessory as claimed in Claim 9, wherein a gap is provided between adjacent castellations of a respective first and second portion, and a spring is located in the gap arranged to bias abutting surfaces of the castellations into engagement with one another.

11. An accessory as claimed in Claim 10, wherein a lever with overcentre action is provided so that, when in an operative position, the abutting surfaces are forced into engagement with one another.

12. An accessory as claimed in Claim 11, wherein the abutting surfaces of the castellations are provided with serrated or ribbed portions, whereby relative pivotal movement is prevented when the lever is in the operative position.

13. An accessory as claimed in Claim 6 or Claim 7, wherein the first and second portions of each respective attachment means are pivotally connected by a bolt or similar fastening, which can be tightened when the first and second portions are in a desired disposition, whereby to prevent undesired relative movement.

14. An accessory substantially as described with reference to the drawings.

15. A ladder provided with at least one accessory as claimed in any of the preceding claims.

16. A ladder as claimed in Claim 15, wherein a said accessory is deployed to the side of the ladder.

17. A ladder as claimed in Claim 16, wherein a said accessory is deployed in a direction out of the plane of the ladder.

18. A ladder as claimed in Claim 15, wherein a said accessory is deployed in line with a stile of the ladder to act as an extension to the stile.

19. A ladder as claimed in Claim 15, wherein at least one accessory is permanently attached to the ladder.