GB2110286A - Light and extensible ladder - Google Patents

Abstract

The ladder comprises a first set of strong and telescopic elements (1-6); a second set of parts (7-12) each comprising a support surface forming one step of the ladder, each part being transversely connected to one element or group of strong elements of the first set, a set of stopper studs and locking means between the various strong elements of the first set arranged so as to ensure at least the stability of the two extreme positions of the ladder, that is, of the ladder folded up on itself and of the extended ladder. <IMAGE>

Description

SPECIFICATION Light and extensible ladder This invention relates to a ladder which may be folded up on itself such that it occupies a minimum amount of space and volume and may be compared with a small suitcase.

In accordance with the invention the steps of the ladder are superposed on one another when the ladder is folded up and the prismatic or cylindrical elements forming the members which support each step are likewise folded up on themselves in this position.

Each step is connected transversely to at least one of these prismatic elements. These different prismatic elements which support each step are strong and, at the same time, they slide with respect to one another and guide one another.

One embodiment of the ladder according to the invention consists in using elements having a circular or square section, of a telescopic type, which slide into one anothet in successive portions, each supporting one step.

When the ladder is folded up the various elements are successively encased inside each other and the steps are superposed on one another, occupying a minimum amount of space and volume.

In order to prevent the various sliding and guiding elements from being able to come apart during the extension or unfolding process stopper plugs are provided between two successive elements of the assembly.

In order to ensure the stability of the unfolding position of each step-supporting portion with respect to the previous step there is also provided at least one locking element between the two elements or pairs of elements which support two successive steps.

In order to enable two supporting sections of successive steps to be released it is also recommended that releasing means be used, which are either manual or automatic, the latter, for example, having eccentric surfaces acting on one or more of the locking elements of the successive portions of the sliding supporting elements.

By way of non-limiting example the embodiments will be described hereinafter with reference to the attached drawings, in which: Figure 1 shows the ladder according to the invention in the transporting position; Figures 2, 3 and 4 show the ladder in different states of use; Figures 5 and 6 show structural details; and Figure 7 shows a variant of the embodiment.

These various figures aim to combine a first assembly of prismatic elements 1 to 6 which are strong and simultaneously slide with respect to one another and guide one another, with a second assembly of steps 7 to 12 such that each step 7 to 12 is connected to at least one of the strong sliding elements 1 to 6.

When a step 7 to 1 2 is connected to two parallel telescopic elements 1 to 6, a preferred method of operating consists, in accordance with figures 5 and 6, in forming the steps 7 to 12 with vertical flanges 13 and forming the upper ends of the elements 1 to 6 with other similar flanges 14 such that the flanges 1 3 and 14 correspond, are superposed and that they bend and overlap conjointly at 15, thus ensuring that there is a perfect connection between the steps and the two telescopic support elements.

The folding zones 1 5 may advantageously be located at a level which is slightly lower than that of the horizontal plane of the step in order that the superposition of the various steps only provides a minimum amount of separation between the successive superposed steps when the ladder is folded up.

The ladder preferably has two sets of steps 7 to 12 and telescopic elements 1 to 6 which may work together by articulating, along the surface 16, the two upper steps 1 2 of each set.

As these two sets are practically identical it is simple to group them in theirfolded-up positions such that the entire assembly, when suitably folded-up and arranged, mav be contained in a very small space (figure 1).

The first step 12, that is the upper step of each set, may be provided with a handle 1 7 which is articulated with and incorporated in the step, thus making it easier to grasp each set or half-ladder.

The weight of all the elements 1 to 12 facilitates the extension of the latter when a vertical pull is exerted on the said handle 1 7.

In order to be able to easily lock the different portions of the sliding and guiding prismatic elements 1 to 6, resilient studs are mounted on the upper part of each lower portion and in a transverse position with respect to the axis of the prismatic element in question, each locking stud being introduced into a hole or housing of the lower part of the following upper portion.

Likewise the releasing of the different portions may be obtained by acting manually upon the ends emerging from the resilient studs or on small external levers connected to the studs. Automatic releasing may be brought about by providing that each portion formed by one or more prismatic elements 1 to 6 supporting a step 7 to 12 comprises at its lower end an eccentric surface or plug such that this surface or plug determines by displacement the releasing of the studs when the upper element or elements is (are) folded up inside the element(s) located immediately below, this releasing process being performed successively on each portion of the ladder folded up on the previous portion.Thus in this automatic method of operation it only remains for the initial releasing moment of the upper portion to be determined by manual means (small lever acting on the locking elements of the upper portion of the ladder) in order to obtain, after this first movement, the successive releasing of all the other portions, until the entire ladder is folded up.

It is evident that other methods of locking and unlocking the successive portions of the ladder are also possible without departing from the scope of the invention.

The ladder which is the object of this invention may also be produced according to the method indicated in figure 4, such that instead of connecting the two similar sets, which support the steps 7 to 12, by means of a hinge or other upper connecting means, the lower end of one set may be encased in a housing in the first step 1 2 of the other set, in order to double the height of the ladder obtained.

Claims (6)

1. Light and extensible ladder, substantially characterized in that it consists of the combination of a first set of strong elements which simultaneously and in successive portions slide with respect to one another and guide one another, and a second set of parts each comprising a support surface forming one of the steps of the ladder, each part or step being transversely connected to one of the elements or group of strong elements forming a portion of the first set; the whole being combined with a third set of stopper studs and means for locking and releasing, as desired, between the various sliding and guiding portions which support the steps, so as to ensure at least that the unfoided and extended position of the ladder is maintained stable, with the successive steps duly separated as well as the telescopic folding-up of the successive portions until the steps are superposed and occupy positions close to one another, the entirety of the members forming the ladder having minimum dimensions and volume.

2. Light and extensible ladder according to claim 1, characterized in that the successive portions have a length which is equal or approximately equal to the distance between two steps.

3. Light and extensible ladder according to claim 1, characterized in that each step rests and is preferably fixed to the lower portions.

4. Light and extensible ladder according to claim 3, characterized in that the fixing between each step and the corresponding portions is obtained by overlapping the flanges provided for this purpose at the upper end of each portion and around the hole of the passage of the portion into the step.

5. Light and extensible ladder according to claim 1, characterized in that the upper steps are provided with a handle.

6. Light and extensible ladder substantially as described above and illustrated in the attached drawings.