GB2428068A

GB2428068A - Stepladder

Info

Publication number: GB2428068A
Application number: GB0513758A
Authority: GB
Inventors: Derek Muir
Original assignee: University of Huddersfield
Current assignee: University of Huddersfield
Priority date: 2005-07-05
Filing date: 2005-07-05
Publication date: 2007-01-17
Also published as: GB0513758D0

Abstract

A stepladder comprising a ladder frame, a support component and a retaining arrangement. The ladder frame comprises first and second substantially coplanar longitudinally extensive side members and at least one step connected there between. The respective side members are arranged such that a lower end of the ladder frame is wider than an upper end of the ladder frame which improves stability against tipping. The ladder frame and the support component are operatively movable with respect to each other between a compact configuration and an extended use configuration, in which the retaining arrangement is operable to retain the stepladder in the use configuration. In the use configuration the stepladder can be placed next to a wall, in such way that the first side member of the ladder frame is substantially coplanar to the vertical plane defined by the wall.

Description

P110707GB spec MY 29-6-05

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IMPROVED STEPLADDER

The present invention relates to stepladders. In particular the present invention relates to a freestanding stepladder having improved stability against tipping.

BACKGROUND

Stepladders are a commonplace item in both household and industrial environments.

They are typically freestanding and comprise a ladder frame hingedly connected along an upper edge of the ladder frame to an upper edge of a support frame of similar size to the ladder frame. In use the lower edge of the support frame is swung away from the ladder frame to stabilise the ladder frame in an upright condition. Restraining means such as a chain or folding rod may be provided to limit the extent to which the support frame may be swung away from the ladder frame.

Stepladders provide a useful platform from which a user may engage in a variety of manual tasks including painting, wallpaper hanging, and installation of wall or ceiling fixtures. When the stepladder is not in use, the support frame is typically folded into juxtaposition with the ladder frame for storage.

Whenever stepladders are used, the possibility of accidental falls from the stepladder inevitably exists. Falls are increasingly likely when the user is distracted by the task at hand. Accident statistics demonstrate that a common accident involves sideways tipping of the stepladder. For example, when the stepladder is positioned in an orientation substantially parallel to a wall, a user may cause the ladder to tip away from the wall, for example during application of pressure to the wall.

US 4798262 discloses a three-legged folding stepladder having outriggertype support extensions on the two front support legs. The support legs contact the ground to form an equilateral triangle when viewed from above. The ladder provides enhanced stability against sideways tipping. However, it is impossible to position the ladder in juxtaposition with a vertical surface in a sideways orientation.

A stepladder as disclosed in DE19637634 is shown in Figure 9. This prior art stepladder is in the form of a tripod arrangement of three upright beams 2, 3, 4 meeting at an apex 6. The ladder has the form of an equilateral triangle when viewed from above. Steps 5 P110707GB spec MY 29-6-05 * . *I I ** S I * I I

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* III III * S I S * I S I S S 2 1 are provided between beams 2 and 3, and between beams 2 and 4. A bracing member 8 is provided between beams 3 and 4. The ladder may be climbed by placing a left foot on a step on the left side of beam 2, and a right foot on a step to the right of beam 2.

However, the nature of the design of the stepladder makes it difficult for a user to work in close proximity to a vertical surface.

Figure 10 illustrates a triangle-shaped ladder A as disclosed in JP8260859, having a pole 5 which is removably connected to a locking part 4 at the upper part of auxiliary ladder 3, forming a tripodal arrangement. The length of the pole 5 is adjustable by leg extension mechanisms 8, 9. The pole 5 projects in a direction substantially perpendicular to steps of the ladder A as viewed from above. With the ladder oriented such that auxiliary ladder 3 is as close as possible to a vertical wall (ie with leg I of the triangle-shaped ladder A and the support member B in juxtaposition with the wall), a user climbing the ladder is required to lean further and further away from the ladder as they climb, in order to reach the wall. This can lead to a tipping instability as the user may thereby apply a sideways component of force to the ladder.

According to the present invention there is provided a stepladder, the stepladder comprising: a ladder frame, the ladder frame comprising first and second substantially coplanar longitudinally extensive sidemembers and at least one step connected therebetween, the respective sidemembers being arranged such that a lower end of the ladder frame is wider than an upper end of the ladder frame; a support component, connected to the ladder frame; and retaining means; wherein the ladder frame and the support component are operatively movable with respect to each other between a compact configuration and an extended use configuration, wherein in the use configuration the first sidemember of the ladder frame lies in a substantially vertical plane and retaining means is operable to retain the stepladder in the use configuration.

The invention has the advantage that the ladder frame may be placed in juxtaposition with a vertical surface such that a sidemember of the ladder frame proximate a vertical wall is disposed substantially parallel to the wall along a substantial portion of the length of the sidemember. Thus, as a user ascends the ladder, the distance between the user P110707GB spec MY 29-6-05 e is.

5* 5 5 I $ I S * S I S I S Ii' SSS S S

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3 I d $ and the wall remains substantially the same. The stepladder may also be folded into a compact configuration for storage purposes.

Preferably, the support component comprises a support frame, the support frame comprising first and second substantially longitudinally extensive sidemembers, the first sidemember of the support frame being substantially in juxtaposition with and connected, preferably by a hinge, to the second sidemember of the ladder frame.

The retaining means may comprise at least one selected from amongst a strap, a chain link, a rigid bar and a hinged bar.

Preferably, in the use configuration the second sidemember of the support frame lies in substantially the same plane as the first sidemember of the ladder frame. This has the advantage of providing increased stability against tipping towards the wall, whilst also allowing the first sidemember of the ladder frame to be positioned in juxtaposition with the wall along at least a portion of the length of the first sidemember.

The stepladder may be in the form of a right-angled triangle when viewed from above.

The ladder frame may be provided with stabilizing means to increase a stability of the ladder against tipping. Alternatively or in addition the support component may be provided with stabilizing means. The stabilising means may comprise a leg, operatively movable between a retracted condition wherein the leg is substantially in juxtaposition with the stepladder, and a deployed use condition wherein the leg is adapted to project from the stepladder to contact a support surface.

The support surface may be a substantially horizontal surface. Alternatively or in addition the support surface may be a substantially vertical surface.

At least one of said ladder frame and said support frame may be of substantially triangular shape.

An upper end of the stepladder may be provided with a ledge. The ledge may be adapted to support at least one handtool of a user.

P110707GB spec MY 29-6-05 4 *4* * 4* g * $ S 4 4 * I I 4 I *4* *44 4 I I * I 4 S *4.

4 III S I S S For a better understanding of the present invention, and to show how it may be carried into effect, reference shall now be made by way of example to the accompanying drawings, in which: FIGURE 1 is a perspective view of a stepladder according to a preferred embodiment of the invention in the extended use configuration with stabilising legs in a retracted condition; FIGURE 2 is a perspective view of a stepladder according to the preferred embodiment with stabilising legs in a deployed configuration; FIGURE 3 is a front elevation of a stepladder according to the preferred embodiment of the invention; FIGURE 4 is a side elevation of a stepladder according to the preferred embodiment of the invention; FIGURE 5 is a rear elevation of a stepladder according to the preferred embodiment of the invention; FIGURE 6 is a plan view of a stepladder according to the preferred embodiment of the invention; FIGURE 7 shows a stepladder according to the preferred embodiment in (a) a partially closed configuration and (b) a closed configuration; FIGURE 8 shows a stepladder according to a second embodiment of the invention; FIGURE 9 shows a stepladder according to the prior art; and FIGURE 10 shows a second stepladder according to the prior art.

According to a first embodiment of the invention, a stepladder 10 comprises a ladder frame 100 and a support frame 200. The ladder frame 100 comprises first and second sidemembers 110, 120 joined together at the apex X of an A' frame, having a series of steps 130 running therebetween. Support frame 200 is similarly in the form of an A' P110707GB spec MY 29-6-05 : :: * a.. I** * . I * S * * III S * S I frame, having first and second sidemembers 210, 220 and a pair of parallel stabilising bars 240 running therebetween. Each of the sidemembers 110, 120, 210, 220 is constructed from aluminium tubing of substantially rectangular cross-section.

The first sidemember 210 of the support frame 200 is hingedly connected to the second sidemember 120 of the ladder frame 100 by upper and lower hinges 190, 195. This allows the support frame 200 to be swung between a compact configuration in which the support frame 200 is in juxtaposition with the ladder frame 100 and an extended use configuration. The position of the ladder frame 100 with respect to the support frame 200 in the use configuration is determined by the length of a strap 300. The strap 300 is connected at one end to a middle portion of the first sidemember 110 of the ladder frame 100, and at the opposite end to a middle portion of the second sidemember 220 of the support frame 200. The strap 300 limits the extent to which the support frame 200 can swing away from the ladder frame 100, thereby enhancing stability and therefore safety of the ladder in the use configuration.

With reference to Figure 6, in the use configuration, the steps 130 and stabilising bars 240 are substantially perpendicular when viewed in plan-view. In plan view, the ladder frame and support frame form a right-angled triangle with corners Al, B and Cl (Figure 6). The angle between side Al-B and side B-Cl is substantially 90 . The first sidemember 110 of the ladder frame 100 is therefore co-linear with the second sidemember 220 of the support frame 200 in the sense that line A1-X-Cl is substantially a straight line.

The first sidemember 110 of the ladder frame 100 and the second sidemember 220 of the support frame 200 are fitted with extendable legs 150, 250. The extendable legs 150, 250 are hinged to a back surface 115, 215 of their respective sidemembers 110, 220 as viewed from the front of their respective frame 100, 200. In a retracted condition (Figure 1, Figure 7(a), Figure 7(b)) the extendable legs 150, 250 are oriented in juxtaposition with their respective sidemembers 110, 220. In an extended condition (Figure 2 to Figure 6) the extendable legs 150, 250 project rearwardly away from their respective sidemembers such that free ends 155, 255 contact the floor surface upon which the stepladder is positioned.

Folding bars 160, 260 restrict the maximum extent to which the extendable legs can be moved. The folding bars 160, 260 each comprise a pair of flat, elongate bars connected P110707GB spec MY 29-6-05 6 1. : together at one end to form a hinge 162 and hingedly connected at opposite ends 264 between an extendable leg 150, 250 and its respective sidemember 110, 220. In the retracted condition the folding bars 160, 260 fold into juxtaposition with their respective leg 150, 250 and sidemember 110, 220; in the extended condition the folding bars 160, 260 unfold and lie in a substantially horizontal orientation.

Whilst a stepladder according to the present embodiment comprises two substantially similar A' frames, each of symmetrical construction (having sidemembers 110, 120, 210, 220 of equal length), in alternate embodiments the sidemembers 110, 120, 210, 220 may be of different lengths. Furthermore, the frames may be truncated A' frames having a substantially flat top portion rather than a substantially triangular profile.

In a second embodiment of the invention the support component comprises a single longitudinally extensive support member 400. The support member 400 is hinged to a back surface 115 of the first sidemember 110 of the ladder frame 100 by a hinge 495. A strap 300 is provided to limit the extent to which the support member 400 can swing away from the ladder frame 100 as in the first embodiment.

In an alternate embodiment, the first sidemember of the ladder frame may be provided with an extendable leg. In a further alternate embodiment, the support member 400 may also be provided with an extendable leg.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of the words, for example "comprising" and "comprises", means "including but not limited to", and is not intended to (and does not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Claims

P110707GB spec MY 29-6-05 * a ** a II.

as 5 I * * * a S I * S S I II * II. *** S I I S * a * * * * * 7 5S* * a I S CLAIMS: 1. A stepladder, the stepladder comprising: a ladder frame, the ladder frame comprising first and second substantially coplanar longitudinally extensive sidemembers and at least one step connected therebetween, the respective sidemembers being arranged such that a lower end of the ladder frame is wider than an upper end of the ladder frame; a support component, connected to the ladder frame; and retaining means; wherein the ladder frame and the support component are operatively movable with respect to each other between a compact configuration and an extended use configuration, wherein in the use configuration the first sidemember of the ladder frame lies in a substantially vertical plane and retaining means is operable to retain the stepladder in the use configuration.
2. The stepladder of claim I wherein the support component comprises a support frame, the support frame comprising first and second substantially longitudinally extensive sidemembers, the first sidemember of the support frame being substantially in juxtaposition with and connected to the second sidemember of the ladder frame.
3. The stepladder of claim 2 wherein the first sidemember of the support frame is connected to the second sidemember of the ladder frame by a hinge.
4. The stepladder of claim I or claim 2 wherein the retaining means comprises at least one selected from amongst a strap, a chain link, a rigid bar and a hinged bar.
5. The stepladder of any one of claims 2 to 4 wherein in said use configuration the second sidemember of the support frame lies in a substantially vertical plane.
6. The stepladder of claim 5 wherein the stepladder is in the form of a right-angled triangle when viewed from above.
7. The stepladder of any one of claims I to 6 wherein the ladder frame is provided with stabilizing means to increase a stability of the ladder against tipping.

P110707GB spec MY 29-6-05 *** * ,,.
S. S * I S S * S S S * S S II * S.. **. S S S S * * S S S S * 8 S 8. The stepladder of any one of claims I to 7 wherein the support component is provided with stabilizing means to increase a stability of the ladder against tipping.
9. The stepladder of claim 7 or claim 8 wherein the stabilizing means comprises a leg, operatively movable between a retracted condition wherein the leg is substantially in juxtaposition with the stepladder, and a deployed use condition wherein the leg is adapted to project from the stepladder to contact a support surface.
10. The stepladder of claim 9 wherein the support surface is a substantially horizontal surface.
11. The stepladder of claim 10 wherein the support surface is a substantially vertical surface.
12. The stepladder of any one of claims ito 11 wherein at least one of said ladder frame and said support frame are of substantially triangular shape.
13. The stepladder of anyone of claims Ito 12 wherein in said use configuration an upper end of the stepladder is provided with a ledge.
14. The stepladder of claim 13 wherein said ledge is adapted to support at least one handtool of a user.
15. A stepladder substantially as herein described with reference to Figures 1 to 8.

15. The stepladder of claim I wherein the support component comprises a longitudinally extensive support member.

16. The stepladder of claim 15 wherein in the use configuration the support member is disposed to lie in a substantially vertical plane.