A ladder

Field of the Invention The present invention relates to ladders, and in particular to ladders that may be folded and unfolded for use as stepladders and as straight extension ladders.

Background to the Invention

Self-supporting folding ladders, or stepladders, are well known and are typically used for household tasks such as painting, cleaning, hedge-clipping etc.

Straight extension ladders are also well known. This type of ladder is typically used outdoors for painting, joinery, building maintenance and repair etc.

Combination ladders constructed to be used as both stepladders and straight extension ladders are also well known. One example of such a ladder is described in US Patent No. 4,182,431. This document describes a combination step and extension ladder. Hinges are provided on each of the side rails of the ladder so that the ladder may be folded and unfolded from a stepladder configuration to a straight extension configuration and vice versa. Additional side rails are provided which are telescopically mounted so that the ladder can be extended to increase its height in either of the stepladder or extension ladder configurations.

There are a number of disadvantages associated with the narrow steps or rungs such as those provided on the ladder described above. In particular, people who are required to use ladders for extended periods of time may find that these narrow steps or rungs become extremely uncomfortable to stand on, and in extreme cases may result in chronic foot pain or injury.

Thus, for many applications, it is desirable to use a ladder with wide platform steps, as these are more comfortable to stand on than traditional ladder rungs or narrow steps. In addition, platform steps may also be used to support a workpiece, a can of paint, tools or other such items. Platform steps are also useful to allow the user of the ladder a wider range of movement than a regular ladder rung. The combination step and extension ladder described above may be provided with a wide platform step by clipping on a platform accessory to one of the ladder rungs to allow that rung to be used as a platform step. However, this is not ideal, as in order to vary the height of the platform, the user must unclip the platform from the rung and clip it onto another rung, or must purchase a large number of the clip-on platforms for use on multiple rungs.

Summary of the Invention

The present invention relates to a ladder comprising: a first pair of side rails; at least one platform step pivotably attached at a front end to the each of the first pair of side rails and pivotably attached at a rear end to each of a second pair of side rails, and wherein the first pair of side rails is moveable relative to the second pair of side rails to move the or each platform step between a substantially horizontal position and a folded position; and a third pair of side rails, having at least one rung provided therebetween, the third pair of side rails mounted to permit extension of the ladder.

In a preferred embodiment, the third pair of side rails is slideably mounted with respect to the first pair of side rails. In an alternative embodiment, the third pair of side rails may be pivotably mounted with respect the first pair of side rails.

The first and second pairs of side rails may be pivotably connected by means of the or each platform step. When the steps are in the horizontal position, the first and second pairs of side rails are arranged in a substantially parallel spaced-apart relationship. When the steps are in the folded position, the first and second pairs of side rails are arranged substantially parallel and adjacent to one another.

An advantage of the present invention is that one or more platform steps are provided as an integral part of the ladder. Thus, there is no need for the user to purchase or attach additional accessories to the ladder in order to provide a platform step. Another advantage is that multiple platform steps may be provided at a range of heights. Additionally, the telescopic or hinged extension arrangement provided by the third pair of side rails allows the height at which the platform steps are arranged to be varied. The ladder of the present invention may thus provide safe and comfortable steps and work platforms at one or more desired heights. A further advantage of the present invention, is that, when folded, the platform steps are substantially flat and parallel to the side rails of the folded ladder.

Suitably, the ladder comprises locking means to lock the platform steps in the horizontal position. This allows the steps to be used safely and securely by a user.

In one embodiment, the ladder further comprises: a fourth pair of side rails having at least one rung provided therebetween, the fourth pair of side rails pivotably attached at a top end thereof to a top end of the second pair of side rails.

The ladder may further comprise a fifth pair of side rails, having at least one rung provided therebetween, the fifth pair of side rails mounted to permit extension of the ladder.

In a preferred embodiment, the fifth pair of side rails is slideably mounted with respect to the fourth pair of side rails. In an alternative embodiment, the fifth pair of side rails may be pivotably mounted with respect the fourth pair of side rails.

Preferably, the fourth pair of side rails is pivotably attached to the second pair of side rails by means of a first set of hinges, whereby the hinges permit the ladder to be used as a stepladder and as a straight extension ladder. Preferably, the hinges permit the fourth pair of side rails to pivot in an arc of at least 180° relative to the second pair of side rails. Thus, the ladder may be used as a stepladder, by arranging the ladder such that the fourth pair of side rails forms an acute angle, ideally an angle of about 30 to 40°, with the second pair of side rails. The ladder may be used as a straight extension ladder by arranging the ladder such that the fourth pair of side rails forms an angle of about 180° with the second set of side rails. In the present context, the terms "top" and "upper" are used to indicate portions of the ladder which are uppermost when the ladder is in a stepladder configuration, and the terms "bottom" and "lower" are used to indicate portions of the ladder which are lowermost when the ladder is in a stepladder configuration. The term "substantially horizontal" is used to indicate that the steps are substantially horizontal when the ladder is in the stepladder configuration.

Each of the third pair of side rails may be substantially U-shaped in cross-section, such that a longitudinal channel is provided therein. The third pair of side rails may be mounted on the first pair of side rails, such that the first side rails are slidably received within the longitudinal channels. Thus, the ladder may be extended and retracted telescopically by sliding the third pair of side rails relative to the first pair of side rails. In an embodiment, locking means is provided to lock the third pair of side rails in a selected position relative to the first pair of side rails. Preferably, the selected position is one of a number of available positions, and in an available position, a rung on the third pair of side rails is substantially aligned with a step on the first pair of side rails. Ideally, in an available position, a top rung on the third pair of side rails is substantially aligned with a step on the first pair of side rails.

Similarly, each of the fourth pair of side rails may be substantially U-shaped in cross- section, such that a longitudinal channel is provided therein. The fifth pair of side rails may be mounted on the fourth pair of side rails, such that the fourth side rails are slidably received within the longitudinal channels. Thus, the ladder may be extended and retracted telescopically by sliding the fifth pair of side rails relative to the fourth pair of side rails. In an embodiment, locking means is provided to lock the fifth pair of side rails in a selected position relative to the fourth pair of side rails. Preferably, the selected position is one of a number of available positions, and in an available position, a rung on the fifth pair of side rails is substantially aligned with a rung on the fourth pair of side rails. Ideally, in an available position, a top rung on the fifth pair of side rails is substantially aligned with a rung on the fourth pair of side rails. The sliding telescopic arrangement provided by the third and fifth pairs of side rails allows the height of the ladder to be varied in both the step ladder and straight extension ladder configurations.

The ladder may be foldable adjacent a lower end of the first pair of side rails. In an embodiment, the ladder comprises a second set of hinges provided adjacent a lower end of the first pair of side rails, to allow the first pair of side rails to be folded at the hinges. The second set of hinges is dimensioned to allow the third pair of side rails to slide past or over them, so that the hinges do not interfere with extension of the ladder. When the ladder is in the step ladder or straight ladder configurations, a portion of the third pair of side rails is arranged adjacent the second set of hinges, such that the first pair of side rails is braced and prevented from folding at the second set of hinges. In addition, the third pair of side rails is slideable to a fully extended position, in which a top end thereof is positioned below the second set of hinges, such that the ladder is foldable at the hinges.

The ladder may be folded into a bench configuration by: moving the first pair of side rails relative to the second pair of side rails to bring the platform steps into the folded position; sliding the third pair of side rails to the fully extended position, such that a top end thereof is positioned below the second set of hinges; folding the ladder at both sets of hinges.

In the bench configuration, the platform steps form a substantially continuous planar surface, which may be used as a bench or as a work platform or scaffold.

In certain embodiments, the ladder may further comprise a handrail. The handrail may be configured such that it may be used in either the stepladder or straight ladder configurations. In an embodiment, the handrail is mounted on one or both of the first pair of side rails. The handrail may be detachably mounted on the first pair of side rails. In one embodiment, the handrail is arcuate in shape such that when the ladder is in the straight ladder configuration, a central portion of the handrail is substantially flush with a rung provided between the fourth pair of side rails. Brief Description of the Drawings

Figure 1 is a side elevation view of an embodiment of a ladder according to the present invention, in a folded configuration;

Figure 2 is a side elevation view of the ladder of Figure 1 in a stepladder configuration; Figure 3 is a side elevation view of the ladder of Figure 1 in a straight extension ladder configuration;

Figure 4 is a side elevation view of the ladder of Figure 1 in a bench configuration;

Figure 5 is a side elevation view of the ladder of Figure 1 in a stepladder configuration for uneven surfaces; Figure 6 is a perspective view of a second embodiment of a ladder according to the present invention, in a folded configuration;

Figure 7 is a perspective view of the ladder of Figure 6 in a stepladder configuration;

Figure 8 is a perspective view of the ladder of Figure 6 in a straight extension ladder configuration; and Figure 9 is a perspective view of the ladder of Figure 6 in a bench configuration.

Detailed Description of the Drawings

A first embodiment of a ladder 100 according to the present invention is shown in Figures 1 to 5. The ladder 100 comprises five pairs of side rails 1-5 and four platform steps 6. Each of the platform steps 6 is pivotably attached at a front end 7 to each of the first pair of side rails 1 and pivotably attached at a rear end 8 to each of the second pair of side rails 2. The top step 6a is pivotably connected at its front end 7a to a top end 18 of the first pair of side rails 1 by means of hinges 17. The hinges 17 contain a spring- loaded locking mechanism which allows them to be locked in position. The lower steps 6 are journaled for pivotal movement to the first pair of side rails 1 by means of pins 19. Each of the steps 6 is journaled for pivotal movement to the second pair of side rails 2 by means of pins 20.

The third pair of side rails 3 is slideably mounted relative to the first pair of side rails 1. Each of the third pair of side rails 3 is substantially U-shaped in cross-section, such that a longitudinal channel is provided therein. The third pair of side rails 3 is mounted on the first pair of side rails 1 , such that the side rails 1 are slidably received within the longitudinal channels. A set of rungs 9 is provided between the third pair of side rails 3. The fourth pair of side rails 4 is hingedly connected at a top end 11 thereof to a top end 12 of the second pair of side rails 2, by means of a set of hinges 10. The hinges 10 permit the fourth pair of side rails 4 to pivot in an arc of at least 180° relative to the second pair of side rails 2. The hinges 10 contain a spring-loaded locking mechanism which allows the ladder to be locked into any of several configurations, as described below. A set of rungs 13 is provided between the fourth pair of side rails 4.

The fifth pair of side rails 5 is slideably mounted with respect to the fourth pair of side rails 4. Each of the fifth pair of side rails 5 is substantially U-shaped in cross-section, such that a longitudinal channel is provided therein. The fifth pair of side rails 5 is mounted on the fourth pair of side rails 4, such that the side rails 4 are slidably received within the longitudinal channels. A set of rungs 14 is provided between the fifth pair of side rails 5.

The ladder 100 further comprises a set of hinges 15 provided adjacent a lower end 16 of the first pair of side rails 1. This allows the first set of side rails 1 to be folded at the hinges 15.

The telescopic arrangement provided by the third and fifth pairs of side rails 3, 5 allows the height of the ladder 100 to be varied by sliding the third and fifth pairs of side rails relative to the first and fourth pairs of side rails 1, 4, respectively.

In Figure 1, the ladder 100 is shown in a folded configuration, in which the first, second and fourth pairs of side rails 1 , 2, 4 are arranged substantially parallel and adjacent to one another. The third and fifth pairs of side rails 3, 5 are arranged in their retracted positions. The steps 6 are folded to form a substantially continuous surface parallel to the side rails.

In Figure 2, the ladder 100 is shown in a stepladder configuration. To convert the ladder from the folded configuration to the stepladder configuration, the fourth pair of side rails 4 is pivoted by means of hinges 10 so that it forms an angle of about 30 to 40° with the second pair of side rails 2, and the first pair of side rails 1 is pivoted relative to the second set of side rails 2 by means of hinges 17 and pins 19 and 20 to bring the steps 6 into a substantially horizontal position and the first and second pairs of side rails 1 , 2 into a substantially parallel spaced-apart relationship. As shown by the dotted lines in Figure 2, the height of the stepladder, and thus the height of the platform steps, may be varied by sliding the third and fifth pairs of side rails 3, 5 relative to the first and fourth pairs of side rails 1, 4, respectively. Locking means are provided to lock the third and fifth pairs of side rails 3, 5 into a selected one of a number of available positions. In each available position, a rung 9, 14 provided on the slideable pair of side rails is substantially aligned with a step 6 or rung 13, respectively. When the ladder is in the stepladder configuration, the first pair of side rails 1 is braced and prevented from folding at hinges 15 by the third pair of side rails 3.

In Figure 3, the ladder 100 is shown in a straight extension ladder configuration. To convert the ladder from the stepladder configuration to the straight extension ladder configuration, the fourth pair of side rails 4 is pivoted by means of hinges 10 so that it forms a an angle of about 180° with the second pair of side rails 2. The height and position of the ladder relative to a wall or other vertical surface may be adjusted by sliding the third and fifth pairs of side rails 3, 5 relative to the first and fourth pairs of side rails 1, 4, respectively. Locking means are provided to lock the third and fifth pairs of side rails 3, 5 into a selected one of a number of available positions. In each available position, a rung 9, 14 provided on the slideable pair of side rails is substantially aligned with a step 6 or rung 13, respectively. In Figure 3, each of the third and fifth pairs of side rails have been extended relative to the first and fourth pairs of side rails, respectively, so that the top rungs 9a, 14a are aligned with the bottom step 6d and the bottom rung 13b, respectively. When the ladder is in the straight extension ladder configuration, the first pair of side rails 1 is braced and prevented from folding at hinges 15 by the third pair of side rails 3.

In Figure 4, the ladder 100 is shown in a bench configuration. To convert the ladder from the straight extension ladder configuration to the bench configuration, the fifth pair of side rails 5 is retracted fully relative to the fourth pair of side rails 4 and the fourth pair of side rails 4 is pivoted relative to the second pair of side rails 2 by means of hinges 10, so that it forms an obtuse angle (of about 100 to 110°) therewith. The first and second pairs of side rails 1, 2 are pivoted so that they are adjacent and parallel (as in the folded configuration), thereby folding the steps 6 flat, so that they form a substantially continuous surface parallel to the first and second pairs of side rails 1, 2. The third pair of side rails 3 is extended fully, so that a top end 21 thereof is arranged below hinges 15. The lower end of the first pair of side rails is then folded by means of hinges 15, to form an obtuse angle (of about 100 to 110°) with the surface formed by the steps 6.

The configuration of the ladder 100 shown in Figure 5 is similar to that shown in Figure 2, except that the third pair of side rails 3 has been extended and the fifth pair of side rails 5 retracted to allow the stepladder to be used on an uneven surface, in this case stairs.

A second embodiment of a ladder 200 according to the present invention is shown in Figures 6 to 9 of the accompanying drawings. The ladder 200 comprises five pairs of side rails 1 to 5 and four platform steps 6, arranged as described above with reference to the first embodiment of the invention. As before, the top step 6a is pivotably connected at its front end 7a to a top end 18 of the first pair of side rails 1 by means of hinges 17.

The hinges 17 comprise a spring-loaded locking mechanism which allows them to be locked in position. A handle 23 is provided on each side of the top step 6a. The handles

23 allow the locking hinge 17 to be released and the ladder to be folded or unfolded easily.

The third pair of side rails 3 is slideably mounted relative to the first pair of side rails 1 as previously described with reference to the first embodiment. Each of the third pair of side rails 3 is substantially U-shaped in cross-section, such that a longitudinal channel 21 is provided therein. The third pair of side rails 3 is mounted on the first pair of side rails 1 , such that the side rails 1 are slidably received within the longitudinal channels 21.

The fourth pair of side rails 4 is hingedly connected at a top end 11 thereof to a top end 12 of the second pair of side rails 2, by means of a first set of hinges 10, again as previously described with reference to Figures 1 to 5. The hinges 10 comprise a spring- loaded locking mechanism that allows the ladder to be locked into any of several configurations, as described below. Each hinge 10 is provided with a release mechanism actuated by a push-button 24 provided at the centre of the hinge 10. In alternative embodiments, the release mechanism may comprise a release lever or handle or any other suitable mechanism.

The fifth pair of side rails 5 is slideably mounted with respect to the fourth pair of side rails 4, as previously described with reference to Figures 1 to 5. Each of the fifth pair of side rails 5 is substantially U-shaped in cross-section, such that a longitudinal channel 22 is provided therein. The fifth pair of side rails 5 is mounted on the fourth pair of side rails 4, such that the side rails 4 are slidably received within the longitudinal channels 22.

The ladder 200 further comprises a second set of hinges 15 provided adjacent a lower end 16 of the first pair of side rails 1. This allows the first set of side rails 1 to be folded at the hinges 15. The hinges 15 comprise a spring-loaded locking mechanism. Each hinge 15 is provided with a release handle 25 to release the hinge lock when the ladder is to be folded or unfolded.

In Figure 6, the ladder 200 is shown in a folded configuration, in which the first, second and fourth pairs of side rails 1, 2, 4 are arranged substantially parallel and adjacent to one another. The third and fifth pairs of side rails 3, 5 are arranged in their retracted positions. The steps 6 are folded to form a substantially continuous surface parallel to the side rails.

In Figure 7, the ladder 200 is shown in a stepladder configuration. To convert the ladder from the folded configuration to the stepladder configuration, the hinges 10 are released by means of push-buttons 24 so that the fourth pair of side rails 4 may be pivoted so that it forms an angle of about 30 to 40° with the second pair of side rails 2. Hinges 17 are released by gripping the handles 23 and squeezing them inwards, towards the top step 6a. The front ends of the handles 23 are arranged to unlock the spring- loaded locking mechanism in hinges 17. The handles are then used to pivot the first pair of side rails 1 relative to the second set of side rails 2 by means of hinges 17 and pins 19 and 20 to bring the steps 6 into a substantially horizontal position and the first and second pairs of side rails 1, 2 into a substantially parallel spaced-apart relationship. The handles are then released so that the hinges 17 lock in position, thereby locking the steps 6 in the substantially horizontal position. Thus, the handles are used as a "push-twist- unlock-lock" mechanism. In alternative embodiments, where no handles are provided, the hinges 17 may be unlocked (for example, by means of push-buttons or release handles) and the steps unfolded simultaneously. However, the handles provide a user- friendly means of unlocking the hinges and folding or unfolding the ladder in one movement, without risk of the user pinching his fingers.

The height of the step ladder, and thus the height of the platform steps, may be varied by sliding the third and fifth pairs of side rails 3, 5 relative to the first and fourth pairs of side rails 1, 4, respectively. Locking bars 26 are provided to lock the third and fifth pairs of side rails 3, 5 into a selected one of a number of available positions. One end of a C-shaped locking bar 26 is spring-mounted at each end of the top rungs 9a and 14a. The other end of each locking bar 26 extends through a hole 27 provided in each of the third and fifth pairs of side rails. Corresponding holes 28 are provided at intervals along each of the first and fourth pairs of side rails 1, 4. In each available position, a rung 9, 14 provided on the slideable pair of side rails is substantially aligned with a step 6 or rung 13, respectively. The step ladder may be locked at a selected height by aligning the holes 27 with a set of holes 28, so that the locking bar extends through both sets of holes, thereby locking the side rails in place relative to one another. When the ladder is in the stepladder configuration, the first pair of side rails 1 is braced and prevented from folding at hinges 15 by the third pair of side rails 3.

In Figure 8, the ladder 200 is shown in a straight extension ladder configuration. To convert the ladder from the stepladder configuration to the straight extension ladder configuration, the hinges 10 are released by means of push-buttons 24 so that the fourth pair of side rails 4 may be pivoted so that it forms a an angle of about 180° with the second pair of side rails 2. The height and position of the ladder relative to a wall or other vertical surface may be adjusted by sliding the third and fifth pairs of side rails 3, 5 relative to the first and fourth pairs of side rails 1, 4, respectively. The ladder may be locked at the desired height by means of locking bars 26 as described above. In each available position, a rung 9, 14 provided on the slideable pair of side rails is substantially aligned with a step 6 or rung 13, respectively. In Figure 8, each of the third and fifth pairs of side rails have been extended relative to the first and fourth pairs of side rails, respectively, so that the top rungs 9a, 14a are aligned with the bottom step 6d and the bottom rung 13b, respectively. When the ladder is in the straight extension ladder configuration, the first pair of side rails 1 is braced and prevented from folding at hinges 15 by the third pair of side rails 3.

In Figure 9, the ladder 200 is shown in a bench configuration. To convert the ladder from the straight extension ladder configuration to the bench configuration, the fifth pair of side rails 5 is retracted fully relative to the fourth pair of side rails 4 and the lower end of the fourth pair of side rails 4 is pivoted relative to the second pair of side rails 2 by means of hinges 10, so that it forms an obtuse angle (of about 110°) therewith. The first and second pairs of side rails 1, 2 are pivoted so that they are adjacent and parallel (as in the folded configuration), thereby folding the steps 6 flat, so that they form a substantially continuous surface parallel to the first and second pairs of side rails 1, 2. The third pair of side rails 3 is extended fully, so that a top end 21 thereof is arranged below hinges 15. A relatively short extension portion 29 of each of the first pair of side rails 1 is provided below the hinges 15. An additional locking hole may be provided in the extension portions 29 so that the third pair of side rails may be locked in position relative to the extension portion by means of locking bars 26. The hinges 15 are then released by means of release handles 25 and the first pair of side rails 1 is folded to form an obtuse angle (of about 110°) with the surface formed by the steps 6.

The platform steps 6 may be locked in the folded or bench position by means of a locking mechanism 30 provided on the bottom step 6d. The locking mechanism 30 comprises a pair of bars 31 arranged beneath the bottom step 6d. The inner ends of the bars are connected to a lever 32. The bars may be spring-biased, such that when the ladder 200 is in the folded or bench configurations, the outer ends of the bars are urged by the spring bias so that they extend beyond the sides of the step 6d. The outer ends of the bars are received in recesses or holes 33 provided in the first pair of side rails 1. This holds all of the steps 6 in the folded (bench) position, thereby allowing the ladder to be safely used as a bench. Similarly, the mechanism may be used when the ladder is in the folded configuration. A key-operated lock 34 may be provided to lock the lever in the selected position, thereby locking the steps 6 in the folded/bench position. In alternative embodiments, the locking mechanism 30 may be provided on any of the platform steps. The key-operated lock may be used to prevent unauthorised use of the ladder by preventing the ladder from being unfolded for use. When the ladder is to be unfolded for use in the stepladder or straight extension ladder configurations, the lever is twisted against the spring-bias to retract the bars 31 , thereby allowing the steps to be moved into the substantially horizontal (stepladder) position. In alternative embodiments, a pair of bolts may be provided instead of a lever-operated locking mechanism. In other embodiments, a clip may be provided to retain the steps in the folded/bench position.

The words "comprises/comprising" and the words "having/including" when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.