EP0106583A2

EP0106583A2 - Device for mounting on the rung of a ladder-like member

Info

Publication number: EP0106583A2
Application number: EP83305723A
Authority: EP
Inventors: David John Rayment
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-10-14
Filing date: 1983-09-26
Publication date: 1984-04-25
Also published as: AU2016583A; JPS5991289A; GB8326085D0; GB2128239A; EP0106583A3

Abstract

The present invention provides a device adapted to be mounted upon the rungs 3 of a ladder-like member 1 and 2, which device comprises a generally rectangular and planar load-bearing member 10 having, preferably at or adjacent one edge thereof, means 12 for engaging a rung 3 of the ladder-like member 1 and 2 and for locating the planar member 10 on the ladder-like member 1 and 2 so that it can be pivotted about the rung 3 on which it is located, the planar member 10 also being provided with a stay 20 adapted to engage with another rung 3 of the ladder-like member 1 and 2 and to retain the planar member 10 extended from the plane of the ladder-like member 1 and 2 and thus form a platform for a user of the ladder-like member I and 2 characterised in that the stay 20 comprises a pair of arms 21 pivotably mounted on the planar member 10 at or adjacent the edge opposed to the rung engaging means 12, each arm 21 carrying means 25 for engaging a rung 3 of the ladder-like member 1 and 2, the arms 21 being spaced apart by a distance not significantly less than the lateral width of the planar member 10, whereby the arms 21 can be disengaged from the rung 3 to permit the planar member 10 and the arms 21 to lie substantially parallel to the plane of the ladder-like member 1 and 2 with the arms 21 lying to either side of a planar member 10 mounted on a lower rung 3 of the ladder-like member 1 and 2.

Description

The present invention relates to a device for mounting on the rungs of a ladder-like device, notably to an accessory for a ladder.
Ladders are often uncomfortable and unsafe to use since the rungs provide only a small surface area on which a user can stand. This is a particular problem where the user remains in one position on the ladder for a long time, as when painting a window frame, or when working on an area to one side of the ladder. In order to reduce these problems, it has been proposed to mount a step on the rungs of the ladder. The step is in the form of a foot support hooked onto a rung with a brace to an adjacent rung of the ladder. However, such a device has hitherto been of a rigid construction. As a result, different sizes are required for different ladders and it is necessary to remove the device when raising or lowering the sections of an extending ladder or when moving the ladder to a new work position.
It has been proposed, for example in BP 2036152, to form a ladder step which comprised a planar member with locating means at its front edge for fitting onto a rung of a ladder. The rear of the planar member was provided with a stay which hooked onto the rung above that on which the planar member was mounted, so that the planar member extended rearwards of the ladder. Such a device can be adapted to fit a number of ladders. However, the planar member would interfere with the second section of an extending ladder and would therefore have to be removed whenever the ladder was to be retracted or extended, considerably increasing the labour required in handling the ladder. Also, since the rung above the planar member prevents the user putting his foot fully onto the platform, the platform supports only part on the users foot and the user cannot rest his heel upon the platform. This means that the user is effectively standing on the ball of his foot, which is tiring and such a device therefore offers little advantage over the rungs of the ladder.
I have now devised a form of support which reduces the above problems and which can provide a simple device for use on a range of ladders. The device of the invention is also capable of being used to form a temporary staircase or seating arrangement.
Accordingly, the present invention provides a device adapted to be mounted upon the rungs of a ladder-like member, which device comprises a generally rectangular and planar load-bearing member having, preferably at or adjacent one edge thereof, means for engaging a rung of the ladder-like member and for locating the planar member on the ladder-like member so that it can be pivotted about the rung on which it is located, the planar member also being provided with a stay adapted to engage with another rung of the ladder-like member and to retain the planar member extended from the plane of the ladder-like member and thus form a platform for a user of the ladder-like member, characterised in that the stay comprises a pair of arms pivotably mounted on the planar member at or adjacent the edge opposed to the rung engaging means, each arm carrying means for engaging a rung of the ladder-like member, the arms being spaced apart by a distance not significantly less than the lateral width of the planar member, whereby the arms can be disengaged from the rung to permit the planar member and the arms to lie substantially parallel to the plane of the ladder-like member with the arms lying to either side of a planar member mounted on a lower rung of the ladder-like member.
By having the spaced apart arms for the stay, the device can be collapsed to lie on the outer face of the rungs with a minimum of the device lying beyond the depth of the stiles or side pieces of the ladder-like member. Thus, the device will not interfere with the extension or retraction of the ladder and can be left in position on the ladder at all times. Also, since the device extends forwardly of the ladder when erected, a user can rest the whole of his foot upon the planar member. It is possible to mount the device in position on the ladder when the ladder is on the ground and then to erect and extend the ladder into the work position. This is to be contrasted with the earlier devices which could only be put into position once the ladder had been erected, which can be hazardous.
The invention can be applied to a wide range of types of ladder-like structures and the term ladder is used herein to denote a structure which has two generally parallel longitudinal members, or stiles, linked by a series of - transverse bars, rods or similar members, herein denoted as rungs. Suitable ladders for present use thus include step ladders as well as extending multi-section ladders. Whilst the invention is of especial use in providing one or more platforms on a conventional multi-section extending ladder, it is also within the scope of the present invention to mount the devices on cross-members in a temporary or permanent construction so as to form a simple staircase or terraced seating arrangement. For convenience, the invention will be described with particular reference to a preferred form thereof as shown in the accompanying drawings in which:

Figure 1 is a diagrammatic perspective view of a ladder carrying a device of the invention;
Figures 2, and 3 and 4 are vertical sections through the ladder of Figure 1 and two alternative forms thereof;
Figure 5 is a plan view of a collapsed device of Figure 1; and
Figures 6 and 7 are diagrammatic views of alternative forms of the device shown in Figure 1.

A ladder comprises two longitudinal side members 1 and 2, having a series of transverse members, or rungs, 3 between them. The members 1 and 2 and the rungs 3 can be made from any suitable material, eg wood or aluminium, and are of conventional form and size. The rungs 3 can be of rounded, squared, D or other cross-section and typically will have a diameter of from 1.5 to 5 cms. The ladder may have only one section, as shown in the drawings, but the invention is of especial value with multi-section extending ladders where the devices proposed hitherto have been unsuited. Such ladders usually comprise two or more sections which nest longitudinally within one another.
The device of the invention comprises a plate-like member 10 which serves as a foot rest for a user. The member 10 is of a generally square or rectangular plan shape and can be made as a simple flat sheet of metal, wood, plastics or other suitable load-bearing material. However, it will usually be preferred to provide member 10 with ribs 11 or other reinforcing members so that adequate strength can be achieved without making member 10 of unnecessarily massive construction. Thus, box or other shaped sections 11 can be welded or otherwise fixed to the underside of member 10.
Member 10 has means 12 for locating the member on a rung 3 of the ladder. This means can take the form of a simple hook which engages with the rung or a channel-like member on the underside of member 10 into which rung 3 fits. The location means is preferably located at or adjacent one ecge of the member 10, preferably within 0 to 5 cms from the edge. Thus, the planar member extends substantially wholly forward from the ladder with its rear edge substantially over the centre line of the rung when in the erected position; and the rear edge will lie at or below the level of the top of the rung when the device is in the collapsed position, as described below. Preferably, the location means 12 is positioned near, or extends to near, the side edges of member 10 to impart lateral stability to member 10 when mounted on the ladder.
The location means is such that member 10 can be pivotted about the rung on which it is mounted or about an axis generally parallel to the longitudinal axis of that rung. Member 10 can thus lie generally parallel to the ladder in the collapsed position as shown in Figure 5; or can be pivotted to the operating position extending from the plane of the ladder, as shown in Figure 2. Thus, the hook or other locating means 12 can be mounted pivotably on member 10, eg. by mounting the hooks 12 at either end of a bar rotatably mounted in brackets on member 10. However, it is preferred that the means 12 are fixedly mounted directly or via a spacer on the underside of member 10 and are in the form of U shaped members into which the rung 3 of the ladder fits loosely so that member 10 can be pivotted about the rung. If desired, the hooks 12 or other locating means are a spring fit onto rung 3 so that member 10 will not be easily dislodged during extension or moving of the ladder.
It is particularly preferred that the means 12 be located substantially at the rear edge of member 10 or within 0 to 2.5 cms thereof. In this way, the rear edge of member 10 will lie approximately over the centre line of the rung on which it is mounted. Thus, when member 10 is pivotted to adopt the collapsed position shown in Figure 5, the upper edge of the member will lie at or below the level of the top surface of the rung on which it is mounted and there will be a gap between the top surface of the next lower rung and the lower edge of the member. A user of the ladder can therefore tread on the top of the rung carrying the member with his feet projecting through the gap and thus still use the ladder when the device is in the collapsed configuration.
Member 10 is also provided with a stay 20 pivotably mounted thereon which engages with a rung of the ladder other than that engaged by the locating means 12 to support the member in the extended position. The stay comprises two arms 21 which are preferably substantially rigid, eg. they are made from rods or bars of metal, and extend generally parallel to, but at least initially spaced from, the sides of member 10. Each arm carries a hook or other rung engaging means 25 at its free end, similar to the locating means 12 described above, for attaching the stay to a rung of the ladder.
The arms 21 are pivotably mounted on member 10 so that, when member 10 is pivotted to adopt the collapsed position in which it lies generally parallel to the outer face of the ladder, the stay can be pivotted on member 10 so that it too lies generally parallel to the ladder and thus does not obstruct movement of other sections of the ladder during extension or retraction of the ladder. If need be, the arms 21 can be formed with a dog-leg configuration as shown dotted in Figure 2 to carry the free ends of the arms 21 and the hook 25 mounted thereon within the stiles of the ladder, as shown in Figure 3. Alternatively, the locating means 12 can be mounted on member 10 via spacer pieces 30 which are of such height that they carry the member 10 sufficiently clear of the front face of the rungs 3 when in the collapsed position for straight arms 21 to be able to lie against the outer faces of the rungs substantially co-planar with the ladder, as shown in Figure 4.
The arms 21 are spaced apart by a distance which is not significantly less than the lateral width of member 10 so that the arms can be sprung onto member 10 or can be laid as an interference fit with or at a clearance fit to either side of a member 10. The arms 21 can be parallel to one another, but this may require that rod 23 be so long that there is excessive lateral play of the rod 23 in the brackets 24. It is therefore preferred to splay or crank the arms 21, as shown in Figure 5, to give them the desired spacing, whilst retaining a comparatively short length for rod 23 which can be housed within the width of member 10. The increased spacing of the arms will also improve the lateral stability of member 10 when mounted on the ladder. The arms 21 can converge from an initial spacing at the cranked portion which would give a clearance, eg. of 0.5 to 5 mms, to either side of member 10 to a spacing into which member 10 is a spring or interference fit, ie. the clearance is 0 to - 2 mm. In this way, the arms 21 will restrict lateral movement of a member 10 mounted on the rung below when a series of the devices is mounted on a ladder.
The stay 20 is preferably mounted on member 10 within 2.5 cms of the front edge of member 10, notably substantially at that edge, ie. within 1 cm thereof, so as to reduce the risk of member 10 tipping if a user places his weight at the edge of the member.
Stay 20 can extend downwardly from member 10 to a lower rung, as shown in Figures 1 and 2; or can extend upwardly to engage a rung higher up the ladder as shown in Figure 6. In the latter case, the hooks 25 are preferably mounted on arms 21 so that the open ends to the hooks are directed back along arms 21. This causes the load on arms 21 to hold the hooks 25 positively in position on the rung.
The device can be provided with other features, if- desired. Thus, the upper face of member 10 can carry anti-slip material and arms 21 can carry clips 26 which engage with a rung of the ladder to hold arms 21 against the ladder when the device is in the collapsed configuration. If desired, the hooks 25 can be loosely mounted upon arms 21 so that they can adopt a position skewed to the axis of the arms to reduce stress on the arms where arm 21 is not normal to the surface of the rung on which it bears and so that arms 21 can bear directly onto the rung.
In a particularly preferred form, the device comprises a member 10 made from a substantially rectangular metal plate having bracing ribs 11 affixed to its under surface; the member 10 having locating means 12 mounted at or adjacent each corner of the rear underside edge of the plate and adapted to engage the rung of a ladder so that member 10 can be mounted upon the rung of a ladder to extend generally normal to the ladder with its rear edge lying substantially over the centre line of the rung and so that member 10 can be pivotted to lie generally parallel to the ladder; a rod 23 is rotatably mounted transversely across the underside of the front edge of the plate with its longitudinal axis within 1 cm of that edge, the free ends of the rod each carrying an arm 21 extending substantially normally to the the axis of the rod, the arms being spaced at least initially by an amount at least equal to the lateral width of member 10 and preferably converging to be a spring or interference fit upon member 10; the free ends of arms 21 carrying means 25 for engaging a rung of the ladder to mount the arms 21 upon a rung adjacent to that upon which member 10 is mounted.
The device can be of any suitable size, depending upon the ladder on which it is to be used and the desired size of the platform to be provided by member 10. Thus, the width of member 10 should not exceed the spacing between the stiles 1 and 2 of the ladder, so that it will lie within them when it is collapsed. Member.10 will typically have a width of from 20 to 50 cms. Member 10 and the stay are preferably sized so that the stay will engage the rung immediately above or below that on which member 10 is located; and so that the upper surface of member 10 will subtend an angle of between 80 and 140° to the longitudinal axis of the ladder and will thus be approximately horizontal when the ladder is in normal use. If desired, the length of the stay 20 can be made adjustable so that member 10 can be substantially horizontal whatever the inclination of the ladder during use. Typically, the stay will be from 15 to 50 cms long. Member 10 will measure, for example, from 10 to 50 cms from front to back, preferably from 10 to 20 cms. As indicated above, it is preferred that there is a gap between the lower edge of member 10 in the collapsed position and the top of the next rung down, so that a user can still use the ladder when the devices of the invention are in the collapsed position. Typically, this gap will be from 5 to 15 cms and, depending upon the ladder to which the device is fitted, this may impose limitations on the size of the member 10. The arms 21 are spaced apart sufficiently for them to fit to either side of member 10. The fit can be a clearance fit or the arms can be aninterference fit against member 10. The spacing can be tapered from a clearance fit by say 1 to 5 cms adjacent the mounting onto member 10 to an interference or spring fit at the free ends of the arms. Thus, arms 21 are spaced apart at their free ends thereof by from 2mms less than the width of member 10 (to permit the arms to be a spring fit onto the menber) to substantially the width of member 10. The arms 21 will thus locate to either side of a member 10 on a lower rung and grip it to hold it laterally. The hooks 25 on the free ends of arms 21 preferably will lie closely to either side of a member 10 on the rung onto which the hooks engage. It is particularly preferred that the hooks 25 extend under thatmember 10 so that the member will bear onto the hooks 25 and retain them in position. For example, the hooks can be formed by bending or otherwise forming a flat bar of material into the desired U shape, the material having a width greater than the diameter of arm 21 so that the hook will extend radially beyond the arm and thus provide a shoulder upon which member 10 can bear.
In practice, it is possible to provide devices of the invention in two sizes to fit the majority of ladder sizes and types on the market at present. Thus, particularly preferred dimensions for the devices of the present invention are member 10 is 200 or 260 mms wide and 163 mms from front to back; two clips made from 20 mm wide strip formed into U shaped clips are mounted on the underside of member 10, 12 mms in from each side edge of member 10 and extending 10mm clear of the rear edge of member 10; rod 23 and arms 21 are formed by bending 10 mm metal rod into the configuration shown in Figure 5 with the arms being 253 and 270 mms long and spaced 203 or 263 mms at the crank and the spacing tapering to 200 and 260 mms at the free ends of the arms; the arms 21 carry hooks 25 made from 16 mm strip formed into U shaped clips so that the member 10 on a lower rung will overlay the hooks 25 of an upper device by 3 mm at each side.
In operation, a ladder is erected against, say, a wall. A device of the invention is then mounted on the ladder at the desired position by engaging the locating means 12 with the appropriate rung 3 of the ladder. The stay 20 is then engaged with the appropriate rung, usually the next one up or down from the locating means. This causes the member 10 to adopt the extended position shown in Figure 1 and thus form a platform extending outwardly from the ladder. Several of the devices can be positioned at intervals up the ladder, eg. to form virtually a staircase from the ladder. Where the devices are placed upon consecutive rungs, the arms 21 of an upper device serve to provide lateral restraint to the member 10 of a lower device in position on the rung and the member 10 of that device will bear upon the hooks 25 of the upper device to held the hooks in position on the rung, thus providing an interlocking construction.
Members 10 extend forwardly of the ladder and the hooks 12 and 25 can be sized so that they do not foul the rungs of an underlying section of a multi-section extending ladder. Thus, not only can the ladder be used in the normal way without the need to remove the devices whenever it is desired to extend or retract the ladder, but a ladder carrying the devices of the invention can be used in circumstances where earlier proposals for such devices could not be used because they extended behind the plane of the ladder, eg. on a roof.
When it is desired to collapse the devices on the ladder, for example when the ladder is to be put on the roof rack of a vehicle for transport or the ladder is to be put away for storage, the stay 20 is disengaged from its rung and the member 10 is pivotted to lie against the ladder, as shown in Figure 5, with stay 20 extended along the ladder. In some cases, the stay may extend beyond the height of the stiles of the ladder and this may be undesirable for storage or transport purposes. To overcome this, arm 21 can be cranked so that strut 20 will follow the line of the ladder to lie within the height of the stiles 1 and 2 of the ladder, as shown in Figure 3. Alternatively, the location means 12 can be mounted on spacer pieces 30 rather than directly upon member 10, as shown in Figure 4. This will raise member 10 from the outer face of the rung 3 on which it is mounted so that strut 20 can lie along the out faces of the rungs and within the height of the stiles of the ladder. The clip 26 on an arm 21 can be engaged with a rung of the ladder in order to retain the stay against the rung. The ladder thus presents essentially the same profile to a conventional ladder for storage and transport purposes, but has the devices nesting within the stiles of the ladder in position ready for erection again when required.
The device of the invention can also be used to construct a staircase in essentially the same way as described above for use on a ladder. The members 10 may be from 1 to 3 metres wide; and it may be desired to provide a number of locating means and stays across member 10, eg. at 10 to 30 cm intervals. The staircase can be formed on a ladder-like member as described above. If desired, this can be free standing rather than supported. Thus, the side arms 1 and 2 can be attached to a base frame 30, as shown in Figure 7, and the centre and head of the staircase supported by arms 31 linking the side pieces 1 and 2 to the base frame 30. By extending the front to back depth of the members 10 and their length, eg. by mounting them side by side, it is also possible to erect a temporary seating arrangement using the devices of the invention. In this case, the user sits on the platform formed by members 10 rather than standing on it.
The invention thus also provides a ladder-like member having mounted thereon one or more devices of the invention.

Claims

1. A device adapted to be mounted upon the rungs 3 of a ladder-like member 1 and 2, which device comprises a generally rectangular and planar load-bearing member 10 having means 12 for engaging a rung 3 of the ladder-like member 1 and 2 and for locating the planar member 10 on the ladder-like member 1 and 2 so that it can be pivotted about the rung 3 on which it is located, the planar member 10 also being provided with a stay 20 adapted to engage with another rung 3 of the ladder-like member 1 and 2 and to retain the planar member 10 extended from the plane of the ladder-like member 1 ands 2 and thus form a platform for a user of the ladder-like member 1 and 2 characterised in that the stay 20 comprises a pair of arms 21 pivotably mounted on the planar member 10 at or adjacent the edge opposed to the rung engaging means 12 carried by the planar member 10, each arm 21 carrying means 25 for engaging a rung 3 of the ladder-like member 1 and 2, the arms 21 being spaced apart by a distance not significantly less than the lateral width of the planar member 10, whereby the arms 21 can be disengaged from the rung 3 to permit the planar member 10 and the arms 21 to lie substantially parallel to the plane of the ladder-like member 1 and 2 with the arms 21 lying to either side of a planar member 10 mounted on a lower rung 3 of the ladder-like member 1 and 2.

2. A device as claimed in claim 1 characterised in that the means 12 for engaging the rung 3 is provided by one or more U shaped members located at or adjacent the rear edge of the planar member 10.

3. A device as claimed in either of claims 1 or 2, characterised in that the stay 20 comprises a rod-like member 23 substantially parallel to the front edge of the member 10 and rotatably journalled in one or more mountings 24 located at or -adjacent the front edge of the planar member 10 and having the arms 21 formed integrally therewith.

4. A device as claimed in any one of claims 1 to 3, characterised in that the arm 21 carries means 26 for engaging a rung 3 of the ladder-like member 1, 2 when the device is collapsed and planar member 10 lies substantially parallel to the plane of the ladder-like member 1, 2.

5. A device as claimed in any one of claims 1 to 4, characterised in that the arms 21 converge towards their free ends whereby the arms 21 are a clearance fit or a spring fit to either side of the planar member 10 of another device when mounted on an adjacent rung 3 of the ladder-like member l_r 2.

6. A device as claimed in any one of claims 1 to 5 characterised in that the rung engaging means 25 carried by the free end of the arm 21 comprises a U shaped or hook-like member.

7. A device as claimed in claim 1 characterised in that it comprises a member 10 made from a substantially rectangular metal plate having bracing ribs 11 affixed to its under surface; the member 10 having locating means 12 mounted at or adjacent each corner of the rear underside edge of the plate and adapted to engage the rung of a ladder so that member 10 can be mounted upon the rung of a ladder to extend generally normal to the ladder with its rear edge lying substantially over the centre line of the rung and so that member 10 can be pivotted to lie generally parallel to the ladder; a rod 23 is rotatably mounted transversely across the underside of the front edge of the plate with its longitudinal axis within 1 cm of that edge, the free ends of the rod each carrying an arm 21 extending substantially normally to the the axis of the rod, the arms being spaced apart at least initially by an amount at least equal to the lateral width of member 10; the free ends of arms 21 carrying means 25 for engaging a rung of the ladder to mount the arms 21 upon a rung adjacent to that upon which member 10 is mounted.

8. A ladder-like member 1, 2 having mounted thereon a device as claimed in any one of claims 1 to 7 characterised in that the rung engaging means 12 carried by member 10 is located upon a rung of the ladder-like member 1, 2 and the rung engaging means 25 carried by arms 21 is engaged with a rung immediately above or below that engaged by the means 12 whereby the planer member 10 is caused to extend forward of the plane of the ladder-like member 1, 2 so as to provide a platform for a user of the ladder.

9. A ladder-like member as claimed in claim 8 characterised in that it has mounted thereon upon consecutive rungs devices as claimed in any one of claims 1 to 7 with the planar member 10 of one device being located upon a first lower rung 3 with the members 25 of the arms 21 of the device mounted on a second upper rung being disposed in a clearance or spring fit to either side of the planar member 10 located upon the first rung with at least part of the rung engaging means 25 carried by those arms being located beneath that member 10 whereby the device on the lower rung is restrained from lateral movement by the arms 21 of the upper device and the arms 21 of the upper device are restrained from upward displacement from their location on the lower rung 3.