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Title:
FOLDABLE LADDER ASSEMBLY
Document Type and Number:
WIPO Patent Application WO/2019/243521
Kind Code:
A1
Abstract:
The current invention concerns an improved ladder assembly.

Inventors:
CALLAERTS SIMON (BE)
Application Number:
EP2019/066379
Publication Date:
December 26, 2019
Filing Date:
June 20, 2019
Export Citation:
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Assignee:
GUAPO VENTURES BVBA (BE)
International Classes:
E06C1/38; B60R3/00; E06C5/24
Domestic Patent References:
WO2000060275A12000-10-12
Foreign References:
US4618027A1986-10-21
US3356180A1967-12-05
FR1076639A1954-10-28
US20170144605A12017-05-25
Attorney, Agent or Firm:
BRANTSANDPATENTS BVBA (BE)
Download PDF:
Claims:
CLAIMS

1. Ladder assembly, comprising :

a. at least two front legs, said front legs being hingedly connected at first ends of the front legs to each other in a shared hinging means; b. at least one back leg, said back leg connected to the hinging means, whereby said back leg is connected at a first end of the back leg to the hinging means;

whereby the front legs are foldable via the hinging means to a substantially parallel position to the back leg, whereby the front and back legs are arranged proximate to and alongside of each other; c. one or more, preferably at least two or three, more preferably two or three, steps, at least one, preferably all, of said steps being hingedly connected to the front legs and to the back legs, and adapted to fold against said front and back legs when said front and back legs are in a substantially parallel position.

2. Ladder assembly according to the preceding claim 1, whereby at least one, preferably all, of said steps are:

i. hingedly attached on an edge of the step to each of the front legs, whereby said hinged attachments are positioned at a fixed position of the front legs, and whereby the hinged attachment is adapted to allow hinged rotation of the step around an axis substantially perpendicular to the front leg; ii. hingedly attached on an edge of the step to the back leg, whereby said hinged attachment is positioned at a fixed position of the back leg, whereby the hinged attachment is adapted to allow hinged rotation of the step around an axis substantially perpendicular to the back leg.

3. Ladder assembly according to the preceding claim 2, whereby said back leg and/or front legs are telescoping legs, adapted for reversibly extending to a predetermined maximal distance, preferably whereby intermediate extended positions are settable.

4. Ladder assembly according to the preceding claim 1, whereby at least one, preferably all, of said steps are: i. hingedly attached on an edge of the step to each of the front legs, whereby said hinged attachments are positioned at a fixed position of the front legs, and whereby the hinged attachment is adapted to allow hinged rotation of the step around an axis substantially perpendicular to the front leg; and

ii. hingedly attached on an edge of the step to a movable connector, said connector being movably attached to the back leg, suitable for hinged rotation of the step around an axis substantially perpendicular to the back leg and whereby the connector is adapted to allow longitudinal movement along said back leg;

ii. whereby said back leg comprises at least one step fixation element for limiting the longitudinal movement of the movable connector in at least one longitudinal direction up to a predetermined position along the back leg.

5. Ladder assembly according to the preceding claim 1, whereby at least one, preferably all, of said steps are:

i. hingedly attached on an edge of the step to a movable connector for each of the front legs, the movable connector being movably attached to the front leg, suitable for hinged rotation of the step around an axis substantially perpendicular to the front leg, and adapted to allow longitudinal movement along said front leg;

ii. whereby said front legs comprise at least one step fixation element for limiting the longitudinal movement of the movable connector in at least one longitudinal direction up to a predetermined position along the front leg, said step fixation elements being positioned at fixed positions on each front leg;

iii. hingedly attached on an edge of the step to the back leg, whereby said hinged attachment is positioned at a fixed position of the back leg, whereby the hinged attachment is adapted to allow hinged rotation of the step around an axis substantially perpendicular to the back leg.

6. Ladder assembly according to the preceding claim 1, whereby at least one, preferably all, of said steps are:

i. hingedly attached on an edge of the step to a movable connector for each of the front legs, the movable connector being movably attached to the front leg, suitable for hinged rotation of the step around an axis substantially perpendicular to the front leg, and adapted to allow longitudinal movement along said front leg; ii. whereby said front legs comprise at least one step fixation element for limiting the longitudinal movement of the movable connector in at least one longitudinal direction up to a predetermined position along the front leg, said step fixation elements being positioned at fixed positions on each front leg;

iii. hingedly attached on an edge of the step to a movable connector, said connector being movably attached to the back leg, suitable for hinged rotation of the step around an axis substantially perpendicular to the back leg and whereby the connector is adapted to allow longitudinal movement along said back leg;

iv. whereby said back leg comprises at least one step fixation element for limiting the longitudinal movement of the movable connector in at least one longitudinal direction up to a predetermined position along the back leg.

7. Ladder assembly according to any one of the preceding claims 1 to 6, wherein each step comprises a first elongate crosslink and a second elongate crosslink and a flexible sheet material, said sheet material being substantially inelastic;

said first crosslink being hingedly attached to a first of the front legs at a first end of the first crosslink, and being hingedly attached to the back leg at the opposite end of the first crosslink, preferably to a movable connector, said connector being movably attached to the back leg and suitable for hinged rotation of the first crosslink around an axis substantially perpendicular to the back leg and whereby the connector is adapted to allow longitudinal movement along said back leg; and said second crosslink being hingedly attached to a second of the front legs at a first end of the second crosslink, and being hingedly attached to the back leg at the opposite end of the second crosslink, preferably to a movable connector, said connector being movably attached to the back leg, suitable for hinged rotation of the second crosslink around an axis substantially perpendicular to the back leg and whereby the connector is adapted to allow longitudinal movement along said back leg;

wherein said sheet material is attached to the first and second crosslinks, and wherein said sheet material is stretched substantially taut between the first and second crosslinks when the crosslinks are unfolded to a deployed position with respect to the back leg.

8. Ladder assembly according to the preceding claim 7, wherein for at least one of the steps, each of the crosslinks comprises an extension component, each substantially parallel to the associated crosslink and substantially extending from the crosslink beyond where said associated crosslink is hingedly attached to the front leg, and wherein the sheet material is attached to said extension components, whereby said sheet material is stretched substantially taut between the extension components when the crosslinks are unfolded to a deployed position with respect to the back leg.

9. Ladder assembly according to any one of the preceding claims 1 to 8, whereby the steps are provided with front hinge elements for the hinged attachment to the front legs or movable connectors attached thereto, and provided with one or more back hinge elements for the hinged attachment to the back leg or movable connector attached thereto, whereby said front hinge elements are separately connected to at least one of the back hinge elements via a rigid, preferably elongate, edge component.

10. Ladder assembly according to any one of the preceding claims 1 to 9, whereby the ladder assembly comprises an elongate extension of the back leg extending from the hinging means, said elongate extension comprising a fixation mechanism for releasably coupling to a roof of a car or a component thereon, or a roof rack, preferably whereby the fixation mechanism comprises one or more hook means.

11. Ladder assembly according to any one of the preceding claims 1 to 9, whereby the back leg is hingedly attached at a first end to the hinging means and/or whereby the back leg is attached at a first end to the hinging means and comprises an internal hinging connection allowing the back end to hinge in at least one plane.

12. Ladder assembly according to the preceding claim 11, whereby the ladder assembly comprises an elongate fixation mechanism extending from the hinging means, said elongate fixation mechanism being adapted for releasably coupling to the roof of a car or a component thereon or a roof rack, preferably whereby the fixation mechanism comprises one or more hook means.

13. Ladder assembly according to any one of the preceding claims 1 to 12, whereby said back leg and/or front legs are telescoping legs, adapted for reversibly extending to a predetermined maximal distance, preferably whereby intermediate extended positions are settable.

14. Ladder assembly according to the preceding claim 13, whereby the fixed positions on the front legs of the step fixation elements or hinged attachments for each step, are equidistant from the hinging means.

15. Ladder assembly according to any one of the preceding claims 1 to 14, whereby said front and/or back legs, preferably both, comprise carbon and/or aluminium.

16. Ladder assembly according to any one of the preceding claims 1 to 15, whereby the steps comprise a plurality of essentially flat sections, whereby each of said sections is hingedly connected to at least one other section, preferably whereby at least one, preferably all, of said hinged connections is adapted to limit the hinged rotation in one rotation sense to horizontal position of the sections.

17. Ladder assembly according to the preceding claim 16, whereby the steps are provided with front hinge elements for the hinged attachment to the front legs or movable connectors attached thereto, and provided with one or more back hinge elements for the hinged attachment to the back leg, preferably at a shared point, or to the movable connector attached thereto, whereby said front hinge elements are separately connected to at least one of the back hinge elements via a rigid, preferably elongate, edge component, and whereby the steps comprise a foothold section, which is hingedly connected to both edge components.

18. Ladder assembly according to the preceding claim 17, whereby the foothold section is substantially symmetrical, and comprises at least two separate foothold subsections, the first subsection being hingedly attached to one of the edge components, the second subsection being hingedly attached to the other second edge component, and the first and second subsection being hingedly attached to each other.

19. Ladder assembly according to the preceding claim 18, whereby the foothold section is substantially symmetrical, and comprises at least three separate foothold subsections, the first subsection being hingedly attached to one of the edge components, the second subsection being hingedly attached to the other second edge component, and the first and second subsection being separately hingedly attached to a third, central subsection.

20. Ladder assembly according to the preceding claim 18, whereby the foothold section is substantially symmetrical, and comprises at least four separate foothold subsections, the first subsection being hingedly attached to one of the edge components, the second subsection being hingedly attached to the other second edge component, the first subsection being hingedly attached to a central third subsection, and the second subsection being hingedly attached to a central fourth subsection, said third and fourth subsection being hingedly attached to each other.

21. Ladder assembly according to the preceding claim 18, whereby the foothold section is substantially symmetrical, and comprises at least five separate foothold subsections, the first subsection being hingedly attached to one of the edge components, the second subsection being hingedly attached to the other second edge component, the first subsection being hingedly attached to a third subsection, and the second subsection being hingedly attached to a fourth subsection, said third and fourth subsection being separately hingedly attached to a fifth, central subsection.

22. Ladder assembly according to any one of the preceding claims 19 to 21, whereby the one or more central subsections is hingedly attached to an elongate connection element on a first end of said connection element, said connection element being hingedly attached to the back leg at the opposite end of the connection element, preferably whereby the central subsection comprises an elongate slot in the plane of said subsection for the hinged connection with the connection element, whereby the connection element is slidably movable along said slot.

23. Ladder assembly according to any one of the preceding claims 17 to 22, whereby the edge components comprise two elongate subsections, whereby the hinge elements extend longitudinally perpendicular to the hinge axes of their respective back and front hinge elements, whereby the two elongate subsections are hingedly attached to each other along a longitudinal edge, and whereby the first foothold subsection is hingedly connected to one of the elongate subsections of a first edge component along the longitudinal edge opposite to the longitudinal edge connected to the other subsection of said first edge component, and whereby the second foothold subsection is hingedly connected to one of the elongate subsections of the second edge component along the longitudinal edge opposite to the longitudinal edge connected to the other subsection of said second edge component.

24. Ladder assembly according to any one of the preceding claims 17 to 23, whereby the edge components are longitudinally extendable.

25. Ladder assembly according to any one of the preceding claims 17 to 24, whereby the foothold section and the edge components are adapted to fold against and partially around the front and/or back legs when said front and back legs are in a substantially parallel position.

26. Ladder assembly according to any one of the preceding claims 17 to 25, whereby the foothold section is provided with a plurality of protrusions extending upwards from the plane of the foothold section, preferably near to the edge or edges of the foothold section directed away from the back leg.

27. Ladder assembly according to any one of the preceding claims 1 to 26, whereby the steps comprise a flexible, substantially inelastic, fabric which is attached to the front and back legs, whereby the fabric is held taut when the front and back legs are folded outwards.

28. Ladder assembly according to any one of the preceding claims 1 to 27, whereby the ladder assembly is provided with a locking mechanism suitable for attaching the ladder assembly to a car roof rack.

29. Ladder assembly according to any one of the preceding claims 1 to 28, whereby the ladder assembly comprises one or more extension elements, suitable for mounting fixedly on a free end of a bar of a roof rack of a car, whereby said extension element is adapted to extend from said bar along the longitudinal axis thereof, and whereby said extended extension element is provided with an attachment element at the free end thereof, and whereby the ladder assembly comprises an elongate fixation mechanism extending from the hinging means, said elongate fixation mechanism being adapted for releasably coupling to the attachment element.

30. Ladder assembly according to the preceding claim 29, whereby the attachment element comprises a loop, and the fixation mechanism comprises a hook for coupling to the loop.

31. Ladder assembly according to any one of the preceding claims 29 or 30, whereby the extension elements comprise an elongate first arm and an elongate second arm, the first arm being suitable for mounting fixedly on the free end of a bar of a roof rack of a car, the second arm being attached to the first arm via at least two separate double hinge connections at separate longitudinal equidistant positions along the first and the second arm, allowing displacement of the second arm with respect of the first arm whereby the first and second arm are held in a parallel position.

32. Ladder assembly according to the preceding claim 31, whereby the first arm has an essentially U-shaped profile, and is adapted to at least partially hold the second arm, whereby the double hinge connections are hinged ly attached at both the first and the second arm, and whereby the first and second arm can be locked in a first and in a second position in which the first and second arm essentially lie in the extension of each other.

33. Ladder assembly according to any one of the preceding claims 29 to 32, whereby the assembly comprises two extension elements for mounting fixedly on two bars of a roof rack of a car at a free end thereof, and whereby the extension elements comprise a locking mechanism for releasably holding the rest of the ladder assembly.

Description:
FOLDABLE LADDER ASSEMBLY

Technical field The invention pertains to the technical field of ladders, specifically for car roof accessibility, and particularly car roof box accessibility.

Background There remains a need in the art for a specific ladder assembly to assist in car roof access, whereby the ladder assembly can be folded to a more compact form, allowing easy use and storage on the car roof of the ladder assembly.

Ladder assemblies are typically very useful in preparation of travelling (or when unpacking) and a car roof box is to be loaded or unloaded, so in situations where cargo space is crucial and highly sought after.

The present invention aims to resolve at least some of the problems mentioned above. In these situations, it is important that the ladder assembly does not take up much space, if any. Therefore, the applicant has developed an assembly which is highly compactable, and even attachable to and storable on a car in certain embodiments, in order to even further conserve cargo space.

Summary of the invention

The present invention provides a compact ladder according to claim 1, and further according to the following claims, for assisting in car roof access, specifically for better accessibility to a car roof trunk of roof box. The advantages of the invention are clear, in that it provides with a compact ladder assembly, which can be compacted in multiple dimensions, and specifically adapted for the purpose of accessing a car roof. Such an assembly, due to its specific functionality, is much safer and more ergonomic than often used alternatives (step stools, generic ladders, etc.).

The tripod structure of the ladder (although additional legs may be present as further support) allows for a very compact folded form (as the legs are placed parallel to and approximate to each other). However, the applicant has further improved on this by providing steps which are hingedly attached to the front and back legs (either directly or indirectly), which can fold against/around the folded in tripod structure of the legs. In this way, a user does not need to remove the steps before folding the tripod of legs against each other, and does not need to place the steps back after folding out the tripod. Such detachable versions are cluttery, can allow loss of parts of the assembly, and besides being highly impractical to a user, also require more cargo space.

Description of figures

Figure 1 shows the back leg and a connector for holding the steps.

Fig ures 2 and 3 show the hinging means on the back leg, and the front legs mounted therein.

Figures 4, 7, 8, 15 and 16A, 16B, 16C show an embodiment of a step of the invention, or parts thereof.

Fig ures 5 and 6 show a partial view of an unfolded step mounted on the ladder assembly

Figures 9A-9B show a view of a folded ladder assembly, with the steps folded around the legs.

Figures 10A-10B-10C show an attachment element according to the invention.

Figure 11 shows a possible embodiment for a folded ladder assembly mounted on extension elements, suitable for coupling to a car roof rack, or bars of said car roof rack.

Figure 12 shows the extension element of Figure 11.

Figure 13 shows an exploded view of a possible embodiment of a ladder assembly according to the invention.

Fig ures 14A-14B-14C show the back leg of a possible embodiment of a ladder assembly according to the invention. Figure 15 shows an exploded view of a step according to a possible embodiment of the invention.

Fig ures 16A-16B-16C show a possible embodiment of a step according to the invention, with an edge component in different stages of extension.

Figures 17A-17B show an extension element according to a possible embodiment of the invention.

Figures 18A-18B respectively show the unfolded ladder assembly attached to a car via the extension element, and the folded ladder assembly mounted on said extension element.

Figures 19A-19B respectively show the unfolded ladder assembly attached to a car via the extension element and provided with a cover, and the folded ladder assembly mounted on said extension element provided under said cover.

Figures 20A-20B respectively show an unfolded and folded ladder assembly according to a possible embodiment of the invention.

Detailed description of the invention

Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

As used herein, the following terms have the following meanings:

"A", "an", and "the" as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more than one compartment.

"About" as used herein referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of +/- 20% or less, preferably +/-10% or less, more preferably +/-5% or less, even more preferably +/-!% or less, and still more preferably +/-0.1% or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention. However, it is to be understood that the value to which the modifier "about" refers is itself also specifically disclosed.

"Comprise", "comprising", and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifiy the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints.

The expression "% by weight", "weight percent", "%wt" or "wt%", here and throughout the description unless otherwise defined, refers to the relative weight of the respective component based on the overall weight of the formulation.

In a first aspect, the invention provides an improved ladder assembly, preferably for car roof accessibility, comprising :

a. at least two front legs, said front legs being hingedly connected at first ends of the front legs to each other in a shared hinging means;

b. at least one back leg, said back leg connected to the hinging means, whereby said back leg is connected at a first end of the back leg to the hinging means; whereby the front legs are foldable via the hinging means to a substantially parallel position to the back leg, whereby the front and back legs are arranged proximate to and alongside of each other; and

c. one or more, preferably at least two or three, more preferably two or three, steps, at least one, preferably all, of said steps being hingedly connected to the front legs and to the back legs, and adapted to fold against said front and back legs when said front and back legs are in a substantially parallel position.

As mentioned, the tripedal structure allows a very compact folded version, while guaranteeing structural stability. Preferably, only a single back leg is present in the ladder. In fact, the back leg provides support directly below a person using the ladder, thus ensuring the safety of said user. The steps or rungs are hingedly connected to each of the legs, which creates a reliable foothold for the user, as the step is thus fixed in 3 out of 4 directions in the plane of the step, and, due to the hinged connection, allows the steps to fold against/around the front and/or back legs when these are folded against each other. The applicant has developed a number of possible renditions that allow the folding of the steps, which are discussed to some extent in what follows.

In general, the front and back legs are connected to allow said legs to be folded against each other in a parallel stance. This can be achieved in a number of fashions, however, the front legs will generally be joined in a common hinging means, although typically with separately articulating or separate jointed connections thereto, as this way the hinging means can be made sturdy as it will need to withstand considerable forces and torque. In preferred embodiments, the back leg will be directly connected to said hinging means, preferably in its turn in a hinged connection. Alternatively, the back leg may have an internal hinged connection, allowing the free end of the back leg to hinge with respect to the end attached to the hinging means.

The steps are connected to the legs so that, when the ladder assembly is fully folded out, the step connection to the legs are at the desired height. This can be achieved via a number of technical measures, as discussed further. Note however, that all of these measures produce a ladder assembly, whereby the steps fold themselves against the legs when the legs are folded alongside each other.

In a first preferred embodiment of the invention, at least one, preferably all, of said steps is:

i. hingedly attached on an edge of the step to each of the front legs, whereby said hinged attachments are positioned at a fixed position of the front legs, and whereby the hinged attachment is adapted to allow hinged rotation of the step around an axis substantially perpendicular to the front leg;

ii. hingedly attached on an edge of the step to the back leg, whereby said hinged attachment is positioned at a fixed position of the back leg, whereby the hinged attachment is adapted to allow hinged rotation of the step around an axis substantially perpendicular to the back leg.

In a possible further embodiment, said back leg and/or front legs are telescoping legs, adapted for reversibly extending to a predetermined maximal distance, though intermediate distances are also settable (as in, locked). The advantage of using telescoping legs, preferably for both the back and front legs, is that the hinged connection between the steps can be fixed with respect to the (longitudinal) position on said legs, so the steps will be guaranteed to be leveled correctly. Also, this way a single action can fully assemble the ladder as is designed. For instance, by extending the legs (one or more), the other legs will extend along with it, and the step(s) will automatically unfold as they are pulled along with the extending legs. Furthermore, the legs will thereby also automatically 'unfold' away from each other.

Alternatively, if the user 'unfolds' the steps, the legs will follow suit as explained above, and the same applies if a user unfolds the legs to diverge away from each other. In short, the assembly is conveniently adapted to allow rapid and efficient assembly through a single action by the user.

Note that the front and/or back legs preferably comprise several telescoping sections. Preferably, the legs are adapted to be extendable via telescoping between the step connections to the legs. Most preferably, the front and/or back legs comprise a distal telescoping section past the most distal step connection, which can allow a user to even further extend the legs when necessary (for instance, when dealing with an uneven terrain).

However, as specified, it is not necessarily so that the legs need to extend (telescopically) in order for the step(s) to unfold. In the most preferred embodiment, this is in fact not the case, though one or more of the front and back legs may still be a telescoping leg.

In a second, alternatively preferred embodiment of the invention, at least one, preferably all, of said steps is:

i. hingedly attached on an edge of the step to each of the front legs, whereby said hinged attachments are positioned at a fixed position of the front legs, and whereby the hinged attachment is adapted to allow hinged rotation of the step around an axis substantially perpendicular to the front leg; and

ii. hingedly attached on an edge of the step to a movable connector, said connector being movably attached to the back leg, suitable for hinged rotation of the step around an axis substantially perpendicular to the back leg and whereby the connector is adapted to allow longitudinal movement along said back leg;

iii. whereby said back leg comprises at least one step fixation element for limiting the longitudinal movement of the movable connector in at least one longitudinal (distally oriented) direction up to a predetermined position along the back leg.

Most of the advantages mentioned for the first embodiment apply here as well. However, in case no telescoping sections are available between each 'segment' of the legs (segment being a length of leg between two steps), a slidable connector may be used to attach the steps to one or more of the legs, whereby the steps are hingedly attached to the slidable connector, whereby the connector slides to allow proper folding of the steps around the legs, and unfolding to the assembled position. Note that the legs are then provided with a 'stopper' to ensure that the connector is positioned correctly (impeding movement along a distal direction along the leg). The fixation element may however be adapted to fully lock the connector in place, in a releasable fashion. In this case, the step is attached to the front legs on fixed positions, but to the back leg via a movable connector, which is the most preferred embodiment of the system, as it allows for easy folding of the steps against the folded front and back legs.

In a third, alternatively preferred embodiment of the invention, at least one, preferably all, of said steps is:

i. hingedly attached on an edge of the step to a movable connector for each of the front legs, the movable connector being movably attached to the front leg, suitable for hinged rotation of the step around an axis substantially perpendicular to the front leg, and adapted to allow longitudinal movement along said front leg;

ii. whereby said front legs comprise at least one step fixation element for limiting the longitudinal movement of the movable connector in at least one longitudinal direction up to a predetermined position along the front leg, said step fixation elements being positioned at fixed positions on each front leg;

iii. hingedly attached on an edge of the step to the back leg, whereby said hinged attachment is positioned at a fixed position of the back leg, whereby the hinged attachment is adapted to allow hinged rotation of the step around an axis substantially perpendicular to the back leg.

We refer to the previously mentioned advantages, which apply here as well.

In a fourth, alternatively preferred embodiment of the invention, at least one, preferably all, of said steps is: i. hingedly attached on an edge of the step to a movable connector for each of the front legs, the movable connector being movably attached to the front leg, suitable for hinged rotation of the step around an axis substantially perpendicular to the front leg, and adapted to allow longitudinal movement along said front leg;

ii. whereby said front legs comprise at least one step fixation element for limiting the longitudinal movement of the movable connector in at least one longitudinal direction up to a predetermined position along the front leg, said step fixation elements being positioned at fixed positions on each front leg;

iii. hingedly attached on an edge of the step to a movable connector, said connector being movably attached to the back leg, suitable for hinged rotation of the step around an axis substantially perpendicular to the back leg and whereby the connector is adapted to allow longitudinal movement along said back leg;

iv. whereby said back leg comprises at least one step fixation element for limiting the longitudinal movement of the movable connector in at least one longitudinal direction up to a predetermined position along the back leg.

We refer to the previously mentioned advantages, which apply here as well.

In a preferred embodiment, each step comprises a first elongate crosslink and a second elongate crosslink and a flexible sheet material, said sheet material being substantially inelastic;

said first crosslink being hingedly attached to a first of the front legs at a first end of the first crosslink, and being hingedly attached to the back leg at the opposite end of the first crosslink, preferably to a movable connector, said connector being movably attached to the back leg and suitable for hinged rotation of the first crosslink around an axis substantially perpendicular to the back leg and whereby the connector is adapted to allow longitudinal movement along said back leg; and said second crosslink being hingedly attached to a second of the front legs at a first end of the second crosslink, and being hingedly attached to the back leg at the opposite end of the second crosslink, preferably to a movable connector, said connector being movably attached to the back leg, suitable for hinged rotation of the second crosslink around an axis substantially perpendicular to the back leg and whereby the connector is adapted to allow longitudinal movement along said back leg; wherein said sheet material is attached to the first and second crosslinks, and wherein said sheet material is stretched substantially taut between the first and second crosslinks when the crosslinks are unfolded to a deployed position.

Note that the latter requirement of the crosslinks being in a deployed position, should be understood as a position wherein the crosslinks are unfolded thereby forming an angle with the back leg of at least 90° with respect to the top part of the back leg, preferably wherein the crosslinks are (releasably) secured in said deployed position. As such, the angle is not necessarily 90°, but can easily be slightly more than 90° with the angle being situated between the top part of the back leg and the crosslink, and in fact preferably is more than 90°. The angle can be expected to lie within the range of about 90° to 135°. Preferably, said angle is at least 95°, more preferably at least 100°, or even 105° and even 110°. Preferably, said angle is at most 130°, more preferably at most 125° or 120°. This can be seen in many of the Figures, for instance Figure 19A.

In a folded position, the crosslinks lie generally parallel to and adjoining the front and/or back legs.

As mentioned in the document, in preferred embodiments, the crosslinks (or edge components in other embodiments) are hingedly attached (typically via a connector) to the back and front leg. In preferred embodiments, the hinged attachment of the crosslinks is via a connector that is provided on the legs. In these embodiments, the connectors on the front and/or back legs are slidably movable with respect to said associated leg (preferably either the connectors on the front leg are movable along a portion of the front leg, with the connectors on the back legs fixed at a position on said back leg, or the connectors on the back leg are movable along a portion of the back leg, and are fixed with respect at a position on the front leg; nevertheless, embodiments may exist where they are movable on both front and back legs). However, in such cases, the movable connector is provided with a limiter to its movement along the leg to which it is attached, whereby said limited matches with a fully deployed ladder assembly. This way, it is ensured that the step is stable to support the user weight.

As can be seen in Figure 20A for instance, the crosslinks are preferably essentially elongate bars or rods, ensuring structural strength thereof, and have hinge connectors on each end that are suitable for hinged coupling to the connectors on the front and back leg.

In an alternative embodiment, the connectors are fixed, and the crosslinks are telescopically extendable. Attachment of the material sheet can be provided at fixed positions, resulting in the sheet being pulled taut as the crosslinks extend to their full length.

In a further preferred embodiment, for at least one of the steps, each of the crosslinks comprises an extension component, each substantially parallel to the associated crosslink and substantially extending from the crosslink beyond where said associated crosslink is hingedly attached to the front leg, and wherein the sheet material is attached to said extension components, whereby said sheet material is stretched substantially taut between the extension components when the crosslinks are unfolded to a deployed position. In some embodiments, the extension component may even be telescopically extendable from the crosslinks themselves. The connection to the sheet material can in such a case be discrete (at the end), or can even extend into a pocket of the sheet material on its edges, thereby pulling it taut.

Note that the above is especially applicable to the higher steps. Considering the front and back legs diverge from each other starting from the point where they connect to each other, it should be understood that they provide a smaller base between them closer to said connection point. As such, it is especially the uppermost (or uppermost 2 or 3) steps that are provided with extension components to enlarge the step surface.

Preferably, the sheet material can be wrapped around the front and back legs when folded substantially parallel against each other. In such a case, the sheet material is provided with a fixation member suitable for 'locking' the wrapped sheet material (see Figures). This can be a hook-and-loop fastener or touch fastener (Velcro tab) for instance, with the sheet material being compatible therewith.

The sheet material can be understood to be flexible, allowing it to be folded to closely wrap around the ladder assembly, but is substantially inelastic. In this context, 'inelastic' is to be understood as not substantially increasing in maximal dimensions when external forces are exerted thereupon. In a preferred embodiment, the sheet material is a woven material, such as textile, as such materials typically show high strength, low elasticity/stretch and high durability.

In a particularly preferred embodiment, the sheet material is provided with a strengthened seam at the free edge connecting the most distal attachment points on the crosslinks (or on the extension components). This ensures the strength of the sheet material and reduces danger of tearing. The strengthened seam can for instance be provided by adding an additional material to said edge and/or by double- folding the sheet material at said edge and essentially forming a looped section there.

The sheet material can be attached to the crosslinks (and optionally to the extension components) either continuously (or essentially continuously), or at a discrete number of points, typically over constant distances from each other.

A particular advantage of using a flexible step surface comprising the sheet material, is that the step does not require a sophisticated folding mechanism, or comprises a multitude of mutually hinging components that fold together. This way, mechanical problems are avoided or at least significantly reduced, as well as the ease of folding and unfolding the assembly, as the sheer act of unfolding effectively stretches the sheet material to its taut condition in which it is suitable to be used as a step.

In a preferred embodiment of the invention, the steps are provided with front hinge elements for the hinged attachment to the front legs or movable connectors attached thereto, and provided with one or more back hinge elements for the hinged attachment to the back leg or movable connector attached thereto, whereby said front hinge elements are separately connected to at least one of the back hinge elements via a rigid, preferably elongate, edge component.

This embodiment ensures a strong connection between the legs, guaranteeing that, when assembled, the legs keep a predetermined distance from each other. Additionally, this connection via the edge component will force the legs apart/unfold the steps when the ladder is set up. Finally, the edge components can serve as anchoring points for the step foothold section to extend from. Such a foothold section may be made from a strong, flexible but inelastic material, for instance a tarp. The flexibility will allow it to be folded when the ladder assembly is folded in, while the inelasticity ensures that it provides proper support when used as footing. Alternatively, the foothold section may be made of metal, plastic, etc., whereby the foothold section is not flexible (though in some embodiments it is self-foldable due to internal hinged attachments).

In a preferred embodiment of the invention, the ladder assembly comprises an elongate extension of the back leg extending from the hinging means, said elongate extension comprising a fixation mechanism for releasably coupling to the roof of the car or a component thereon, for instance (a bar of) a car roof rack, preferably whereby the fixation mechanism comprises one or more hook means.

In order to ensure the safety of the user, the ladder assembly is adapted to connect with the car at an upper section of the ladder. This way, the ladder cannot tilt backwards, and cannot move in general when a user is interacting with it, for instance when handling heavy luggage. As most cars with car roof boxes typically have a mounting system therefore, the ladder assembly preferably has a fixation mechanism specifically adapted for the most common roof box mounting systems. These are typically roof rack bars, so one or more hook mechanisms are the most practical option. Note that the extension is not necessarily parallel with the back leg, though it is preferably so to best transfer force to said back leg. The extension may also lie in the plane of the front legs (typically functioning as a bisector therefor), or be an 'averaged' (weighted or not) extension of all three legs.

Preferably, the elongate extension is parallel to, and telescopically retractable into, the back leg. In general, a locking mechanism will be provided to secure the position of the extension (for instance a screw which locks the position of the extension).

In a preferred embodiment of the invention, the back leg is hingedly attached at a first end to the hinging means and/or the back leg is attached at a first end to the hinging means and comprises an internal hinging connection allow the back end to hinge in at least one plane.

The embodiment above has previously been discussed. Depending on the structure of the ladder assembly, the back leg may need to extend somewhat more along with the front legs in order to achieve the necessary distance from the car itself before folding downwards to the ground when in use. An internal hinging connection of the back leg could thus provide a solution.

In a preferred embodiment of the invention, the ladder assembly comprises an elongate fixation mechanism extending from the hinging means, said elongate fixation mechanism being adapted for releasably coupling to the roof of the car, or a component thereon (for instance a - bar of a - car roof rack), preferably whereby the fixation mechanism comprises one or more hook means.

In a preferred embodiment, the back leg and/or front legs are telescoping legs, adapted for reversibly extending to a predetermined maximal distance (with intermediate positions settable). Preferably, both back and front legs are telescoping legs.

The use of telescoping legs is clear in this case, especially in view of one or more of the previously discussed embodiments. Furthermore, it makes the ladder assembly even more compact in the folded version, which is advantageous due to the limited cargo space that is needed, as well as the easier handling of the assembly that is made possible. However, further advantages are that the ladder assembly is automatically adapted for different situations (uneven terrain, unexpected height differences, different car roof heights, etc.). Lastly, as mentioned before, by providing telescoping sections on the legs between subsequent steps, the ladder can be made to automatically unfold, leading to a correct positioning of the steps.

In a preferred embodiment, the fixed positions on the front legs of the step fixation elements or hinged attachments for each step, are equidistant from the hinging means. This ensures a levelled position for the steps when the ladder is unfolded.

In a preferred embodiment, said front and/or back legs, preferably both, comprise carbon and/or aluminium. Alternatives and/or combinations are of course possible, such as steel (optionally coated, e.g. with chrome/chrome alloy), titanium, and others. Note that this list is not to be considered as limitative, and further material choices which would be considered by the person skilled in the art, are included in the invention.

In a preferred embodiment, the steps comprise a plurality of essentially flat sections, whereby each of said sections is hingedly connected to at least one other section, preferably whereby at least one, preferably all, of said hinged connections is adapted to limit the hinged rotation in one rotation sense to horizontal position of the sections. Note that this can be achieved by one or both of two sections which are hingedly attached to comprise one or more extensions (lying in the same plane as the section from which it traverses), which extensions traverse the shared hinge axis, and can thus serve as a stopper for the other section. Alternatively or in combination, the adjoining sides of the section may be adapted, preferably provided with a flat surface perpendicular to the plane of the section, in order for the adjoining sides to lie against each other when in a parallel position (as can be seen in the Figures), and to thereby limit the hinging of said subsection up to a parallel position, but no further. In a further preferred embodiment, the steps are provided with front hinge elements for the hinged attachment to the front legs or movable connectors attached thereto, and provided with one or more back hinge elements for the hinged attachment to the back leg, preferably at a shared point, or to the movable connector attached thereto, whereby said front hinge elements are separately connected to at least one of the back hinge elements via a rigid, preferably elongate, edge component, and whereby the steps comprise a foothold section, which is hingedly connected to both edge components.

In a first, even further preferred embodiment, the foothold section is substantially symmetrical, and comprises at least two separate foothold subsections, the first subsection being hingedly attached to one of the edge components, the second subsection being hingedly attached to the other second edge component, and the first and second subsection being hingedly attached to each other.

In a second, alternative, even further preferred embodiment, the foothold section is substantially symmetrical, and comprises at least three separate foothold subsections, the first subsection being hingedly attached to one of the edge components, the second subsection being hingedly attached to the other second edge component, and the first and second subsection being separately hingedly attached to a third, central subsection.

In a third, alternative, even further preferred embodiment, the foothold section is substantially symmetrical, and comprises at least four separate foothold subsections, the first subsection being hingedly attached to one of the edge components, the second subsection being hingedly attached to the other second edge component, the first subsection being hingedly attached to a central third subsection, and the second subsection being hingedly attached to a central fourth subsection, said third and fourth subsection being hingedly attached to each other.

In a fourth, alternative, even further preferred embodiment, the foothold section is substantially symmetrical, and comprises at least five separate foothold subsections, the first subsection being hingedly attached to one of the edge components, the second subsection being hingedly attached to the other second edge component, the first subsection being hingedly attached to a third subsection, and the second subsection being hingedly attached to a fourth subsection, said third and fourth subsection being separately hingedly attached to a fifth, central subsection. In preferred embodiments, the plurality of flat sections comprises one or more triangular sections and/or one or more rectangular sections and/or one or more pentagonal and/or one or more hexagonal sections.

In a further preferred embodiment, the one or more central subsections is hingedly attached to an elongate connection element on a first end of said connection element, said connection element being hingedly attached to the back leg at the opposite end of the connection element, preferably whereby the central subsection comprises an elongate slot in the plane of said subsection for the hinged connection with the connection element, whereby the connection element is slidably movable along said slot. Such a connection allows for a more secure footing when the ladder is in use. The distance between the back leg and the step is thus dependent on the state of 'foldedness' of the ladder, as the connection element can slide along said elongate slot. Preferably the elongate slot is provided so that the connection element (partially) extends below (when using the ladder correctly) the plane of the step, and thus serves as a lever to delimit the position of the step (or at least the back portion of the step).

In a further preferred embodiment, the edge components comprise two elongate subsections, whereby the hinge elements extend longitudinally perpendicular to the hinge axes of their respective back and front hinge elements, whereby the two elongate subsections are hingedly attached to each other along a longitudinal edge, and whereby the first foothold subsection is hingedly connected to one of the elongate subsections of a first edge component along the longitudinal edge opposite to the longitudinal edge connected to the other subsection of said first edge component, and whereby the second foothold subsection is hingedly connected to one of the elongate subsections of the second edge component along the longitudinal edge opposite to the longitudinal edge connected to the other subsection of said second edge component.

In a preferred embodiment, the edge components are longitudinally extendable, in a retractable fashion, preferably comprising a spring for automatic retraction. This allows the back legs and front legs to be moved apart from each other. This extendibility can be seen in Figures 16A-C.

Note that this particular embodiment is disclosed in detail in the Figures, and will be further discussed there. In a further preferred embodiment, the foothold section and the edge components are adapted to fold against and partially around the front and/or back legs when said front and back legs are in a substantially parallel position.

In a further preferred embodiment, the foothold section is provided with a plurality of protrusions extending upwards from the plane of the foothold section, preferably near to the edge or edges of the foothold section directed away from the back leg. Said protrusions are provide to create friction when a user's foot is placed on the step, so he or she won't slide off of said step. The protrusions may furthermore be coated with a gripping layer (or the gripping layer, for instance rubber, may be present without protrusions being present).

In a preferred embodiment, the steps comprise a flexible, substantially inelastic, fabric which is attached to the front and back legs, whereby the fabric is held taut when the front and back legs are folded outwards. Instead of a mechanically 'folding' foothold section, the step may be provided via a strong fabric, for instance a tarp. The advantage is that it will easily fold away, but due to its inelastic nature, once the ladder is folded out, it will not stretch further.

In a preferred embodiment, the ladder assembly comprises one or more extension elements, suitable for mounting fixedly on a free end of a bar of a roof rack of a car, whereby said extension element is adapted to extend from said bar along the longitudinal axis thereof, and whereby said extended extension element is provided with an attachment element at the free end thereof, and whereby the ladder assembly comprises an elongate fixation mechanism extending from the hinging means, said elongate fixation mechanism being adapted for releasably coupling to the attachment element. The extension element or elements allow for the roof rack bars to be prolonged artificially, away from the side of the car. This allows the ladder assembly to be mounted on the attachment element of the extended extension element, which ensures that the ladder can be properly supported (with the back leg being generally vertical, as the car on which it is mounted does not block such a position due to the extended extension element). Furthermore, by using such extension elements, the ladder assembly can be positioned under a relatively steep angle (over 60°, preferably over 65°, more preferably over 70°, most preferably about 75°), which is desirable for a ladder. In a preferred embodiment, the attachment element and the fixation mechanism are adapted to be (correctly and securely) attachable under a certain orientation, resulting in the above mentioned orientation with respect to the ground and the car.

In a further preferred embodiment, the attachment element comprises a loop, and the fixation mechanism comprises a hook for coupling to the loop.

In a further preferred embodiment, the attachment element comprises a curved section, preferably a curved internal edge of the loop, on which the hook can be mounted. The advantage is that this curved section allows the hook to be mounted under different angles, in turn allowing the ladder assembly to be placed vertical on inclines (when car is parked on a hill, for instance).

In a preferred embodiment, the extension elements comprise an elongate first arm and an elongate second arm, the first arm being suitable for mounting fixedly on the free end of a bar of a roof rack of a car, the second arm being attached to the first arm via at least two separate double hinge connections at separate longitudinal equidistant positions along the first and the second arm, allowing displacement of the second arm with respect of the first arm whereby the first and second arm are held in a parallel position. The arms are adapted to fold into or against each other in a first parallel position, and to fold out to a second parallel position in order for the arms to lie at least partially in each other's extension, whereby the first arm acts as a lever to hold the second arm into position.

In a further preferred embodiment, the first arm has an essentially U-shaped profile, and is adapted to at least partially hold the second arm, whereby the double hinge connections are hinged ly attached at both the first and the second arm, and whereby the first and second arm can be locked in a first and in a second position in which the first and second arm essentially lie in the extension of each other. Such a locking mechanism can be achieved via the 'knuckle' of the hinge, which can be modified into a slot, which slot comprises a portion in which the 'pin' of the hinge connection can rotate, and a more narrow portion, in which the pin is locked in a certain orientation. Once the arms are positioned in a position where the two lie in each other's extension, the pin can be slid from the rotatable portion, in to the narrow portion.

In a preferred embodiment, the assembly comprises two extension elements for mounting fixedly on two bars of a roof rack of a car at a free end thereof, and whereby the extension elements comprise a locking mechanism for releasably holding the rest of the ladder assembly. In order to accomplish this, the extension elements may comprise a slot which extends transversally, on which the rest of the ladder assembly may rest. The extension element could then comprise one or two locking components which can extend and retract (by the user via a key, code or other means), thereby clamping the rest of the ladder assembly (for instance, at the back leg and/or one or both of the front legs). Additionally, the extension element may furthermore be provided with one or more straps to hold the ladder assembly against the extension element.

In a further preferred embodiment, the distal ends of the front and/or back legs are not perpendicular to their longitudinal axis. This is to ensure maximal contact surface between a support surface and the distal ends of the legs when the ladder assembly is used (note that said skewed orientation is preferably chosen to accommodate 'normal' use situations).

In further preferred embodiment, the front and/or back legs are provided with anti- slippage components at the distal ends thereof to ensure a reliable grip on the ground.

In a preferred embodiment, the ladder assembly may be provided with a handle on at least one of the legs for easy transportation.

In a preferred embodiment, the ladder assembly may be provided with a lock for attachment of the ladder assembly to a car roof rack, while maintaining the folded form of the ladder assembly.

The invention is further described by the following non-limiting examples which further illustrate the invention, and are not intended to, nor should they be interpreted to, limit the scope of the invention.

The present invention will be now described in more details, referring to examples that are not limitative.

Examples

Example 1 : Ladder assembly

As can be seen in the Figures, this particular embodiment of the invention comprises two front legs, a back leg and three steps, as well as an elongate extension of the back leg which comprises a fixation mechanism in the form of a hook on its end for attachment to a car roof (specifically, to a car rack). The two front legs are attached to the back leg via a hinging means, to which the front legs are hingedly attached, allowing rotation in a plane (preferably a separate plane for each front leg). In this version, the back leg is fixedly attached to the hinging means (though in alternate embodiments, it can be hingedly attached itself to the hinging means). On said hinging means, an elongate extension is provided, which essentially defines a continuation of the back leg (again, may differ in other embodiments, thus not being parallel to the back leg). Note that the elongate extension in this case is slidably retractable into the back leg, as a telescoping extension, and can be locked into position via a screw, as seen in the Figures. At the distal end of said extension, a gripping means is provided as fixation mechanism, in the form of a hook. The hook is provided with a protective cover of a softer, more malleable material, such as rubber, in order to avoid damage to a car roof or car roof rack.

The steps are hingedly attached to the front legs at predetermined distances (to ensure a leveled position when unfolded), and at fixed (longitudinal positions). The hinged attachment to the back leg however is not fixed, but via a connector which is slidably movable along the longitudinal axis of the back leg. The back leg is provided with stopper or fixation elements which delimit the movement of the connector (one fixation element for each of the connectors) towards the free end of the back leg, this in order to support the step when a person uses the ladder.

Figure 1 shows a more detailed view of the hinged connection (2, 7) for the steps to the back leg (1). The extension (4) of the back leg, upon which a fixation mechanism is provided, is also visible, and can be telescopically extended. The hinged connection is movable along the length of the back leg (1), and is limited in its movement by a stopper (33) to ensure a proper positioning.

Figure 2 shows the hinging means (25), at which the back leg (1) and front legs (3) are hingedly connected (32). The telescopically extending extension (4) can also be seen, as well as a locking component (5) to longitudinally lock the position of said extension (4). Figure 3 shows an internal view of Figure 2.

Figure 5 and 6 disclose the hinged connection (2, 7, 12, 14, 13) of a possible embodiment of a step (6), with the hinges between the subsections thereof depicted, to the back leg (1) and front legs (3) respectively.

Figure 8 shows an unfolded step (6) connected to the front legs (3) and back leg (1), whereby the step (6) is hingedly connected (13) to the front legs (3) at fixed connection (14) via the edge component (8), which edge component (8) is hingedly connected (12) to the back leg (1) at the movable connector (7). From said edge component (8), the other subsections (9a, 9b, 9c, 9d) of the step are hingedly (11) attached back to back. The step is provided with ridged protrusion (16) at the edges facing away from the back leg thereof, to allow better traction for a user.

Figure 9A and 9B show views on part of the ladder assembly when fully folded in, from different perspectives. It is of particular note that the steps themselves are folded around the collapsed legs (1, 3). Furthermore, two handles (17) are provided for easy manipulation of the assembly.

Figures 10A-10B-10C, and also Figure 11, show the fixation mechanism (18), specifically the hook (19) that is used to attach the ladder assembly to an object, typically a car roof rack, or preferably a specifically adapted extension element (21) with an attachment component (20) that is suitable for the hook (19) to couple with. Figure 11 shows the folded in ladder assembly, along with a kit (21) that is adapted to be mounted on a car roof rack, as extensions for said roof rack, to which the ladder assembly can couple. This Figure perfectly shows the compactness of the invention, and the ease with which it can be stowed away on a vehicle.

Figure 12 shows such an extension element (21) adapted to be mounted on the roof rack bars of a vehicle, from which it can be extended, away from the side of the car. The extension element (21) is provided with an attachment element (20) at its free end, and in this case with a lock (22), which can serve for a number of purposes: fixation to the roof rack bar, allowing/disabling the extension of the extension element, locking the ladder assembly into place in the depression (23) adapted to receive the legs of the ladder assembly. Note that said depression (23) is furthermore provided with hooks (24) on which a strap can be hooked to further clamp a ladder assembly against the extension element (21).

Figure 13 shows an exploded view, in which the elongate extension (4) can be seen to lie parallel to the back leg (1), and is in fact telescopically extendable and retractable therein.

Figure 14A-B-C show the back leg (1), along with the telescopically extendable extension (4) with hook (19), the locking component (5), and the hinging means (7), and a number of connectors (25).

Figures 17A and 17B show the extension element (21) which can be fixedly mounted on the roof rack bars of a car. The attachment element (20) is provided on a second arm (28), which can be extended from the first arm (29) via a double-hinging connection (32, 30, 31) as discussed in the description.

Figures 18A and 18B respectively show the ladder assembly deployed on a car (unfolded and functionally attached), and mounted on a car roof rack (folded).

In a further embodiment according to Figures 19A and 19B, the ladder assembly can be provided with an (aerodynamic) cover (34), which substantially allows storage thereunder of the folded ladder assembly, for protection from external forces and atmospheric conditions (hail, snow, etc.)· The cover can be a flip cover, attached with at least two hingable connections to the car roof or a support structure thereon (car roof rack for instance), allowing the cover to be flipped over an axis along the length of the car, and allowing easy storage and closure for increased protection. By providing a cover, the aerodynamic properties of the car can be increased, and noise is reduced.

Example 2: Step

In what follows, the steps will be discussed mainly in an unfolded form. Should this not be the case, this will be clearly stated. In the particular embodiment of the Figures, the step comprises 9 flat subsections. The step comprises two edge components, each to connect a hinged attachment to the back leg to the hinged attachment to one of the front legs (along a first and second axis). Hinged ly attached to these is a first or second intermediate edge component, with a hinge axis parallel to the first or second axis. To these first or second intermediate edge components, a first or second subsection (depending on the side) is hingedly attached, again along a hinge axis parallel to said first or second axis. Subsequently, the first or second subsection is hingedly attached to respectively a third or fourth subsection, along a hinge axis which is not parallel to the previously mentioned first or second axis. Preferably, the angle between the hinge axis connecting the first and third (or second and fourth) subsections and the first axis (or second axis) is about a quarter of the angle between the first and second axis. Lastly, both third and fourth subsection are hingedly attached to a fifth subsection, whereby the hinge axis between the third and the fifth is parallel to the hinge axis between the fourth and fifth subsection, which is parallel to the bisector of the first and second axis.

The fifth subsection is attached to the back leg in turn, via a connection element which is hingedly attached to both the back leg and the fifth subsection (with the hinge axes being parallel to the plane of the fifth subsection and perpendicular to the back leg). Note that the connection between the connection element and the fifth subsection is movable along an elongate slot at the bottom of the fifth subsection, extending away from the back leg along the bisector of the first and second hinge axes. As can be seen from the other Figures, this setup allows the subsections to fold perfectly against each other, and against/around the front and/or back legs. Figure 4, 15 and 16A-B-C show an embodiment of a step, along with a connector (7) to the back leg (1). The step comprises elongate edge components (8) which connected hingedly (12) to the connector (7), and also have a hinging connection (13) to the front legs. The edge component (8) is hingedly (11) attached to a second intermediate edge component (9a), which are hingedly connected (11) to the first and second subsections (9b), which in turn are hingedly connected (11) to the third and fourth subsections (9c), which are hingedly connected 11) to the central, fifth subsection (9d). Note that said fifth subsection (9d) is hingedly connected in turn to the back leg via an intermediate hinge component (10), which connection is further shown in Figure 7. Here, the elongate slot (16) is seen in which the hinge component (10) is seen to be slidably and hingedly connected.

Note that in Figures 16A-B-C, the edge component (8) is extendable (26) along its longitudinal axis (while remaining rigid) to allow the legs to fold away from each other, while maintaining the hinged connection.

Alternative step:

Figures 20A-20B show an alternative embodiment for a step, wherein the step comprises a sheet material (35) held taut between two crosslinks (37) which serve as mutually hinged (13, 12) connection elements to the back leg (1) and the front leg (3), via the respective connectors (7, 14). In this embodiment, the crosslinks (37) are further provided with an extension component (38) projecting along the length of the crosslinks (37) beyond the connector (14) to the front leg (3), whereby the sheet material (35) is furthermore stretched between said extension components (38), ensuring sufficient surface for footing. Additionally, a fixation member (36) is provided on the sheet material (35), in this case in the form of a touch fastener (Velcro), allowing the sheet material to be fixed after wrapping around the folded legs, as can be seen in Figure 20B.

It is supposed that the present invention is not restricted to any form of realization described previously and that some modifications can be added to the presented example of fabrication without reappraisal of the appended claims. The ladder assembly may just as easily be used for other applications, such as for trees (combined with a specific attachment system to the tree, for instance a tightenable loop to fit around the tree, and a connector for the fixation mechanism of the ladder assembly), or for general use with a suitable fixation mechanism, or even more specific uses in automobiles, such as for vans and small trucks. It is of further note that the extension elements themselves form a further aspect of the invention on their own.