This patent application claims priority from Italian patent application no. 102019000024307 filed on December 17, 2019.

The present invention relates to a ladder.

In particular, the present invention relates to a ladder of the type comprising two uprights on which a plurality of steps are applied crosswise and adapted to enable overcoming differences in height with a minimum horizontal bulk.

Furthermore, the present invention also relates to an assembly kit for the ladder wherein the steps and the two uprights are disassembled.

As is known, ladders are provided by producers already assembled, and the plurality of steps are fastened to the two uprights by means of suitable irreversible fixing operations such as welding.

Unfortunately, this type of assembly procedure leads to an increase in manufacturing, maintenance and shipping costs.

Further ladders are known such as for example those described in DE 22 26 213 A, FR 819 114 A and US 4 204 587 A.

The applicant has thus developed an assembly procedure of the components of the ladder of simple production, easy to carry out also by the end user. The procedure requires only the use of common tools/instruments such as hammers and/or screwdrivers, without having to resort to dedicated tools, thus enabling the shipping of the ladder dismantled, reducing the transportation costs thereof.

This object is achieved by the present invention as it relates to a ladder and to an assembly kit for the ladder, according to what defined in claim 1 and preferably, but not necessarily, in any one of the claims depending thereon.

The present invention will be described with reference to the accompanying drawings, which illustrate a nonlimiting embodiment thereof, wherein:

• Figure 1 is a perspective view of a ladder manufactured according to the present invention;
• Figure 2 shows, on an enlarged scale for clarity, the interlocking which is enabled between an end of a step and an upright illustrated in Figure 1;
• Figure 3 shows, on an enlarged scale for clarity, one of the outer holes obtained on the outer wall of each upright illustrated in Figure 1;

• Figure 4 shows, on an enlarged scale for clarity, one of the inner holes obtained on the inner walls of each upright for enabling the passage of the step illustrated in Figure 1;
• Figure 5 illustrates one of the steps, and shows the toothed slits made on both side walls of each step illustrated in Figure 1.

The present invention will now be described in detail, with reference to the accompanying figures, so as to enable a person skilled in the art to manufacture it and use it. Various modifications to the described embodiments will be immediately apparent to those skilled in the art and the general principles described can be applied to other embodiments and applications without thereby departing from the scope of protection of the present invention, as defined in the appended claims. Therefore, the present invention is not to be understood as limited to a preferred embodiment described and illustrated, but it is to be understood as having the widest scope of protection compliant with the principles and with the characteristics described and claimed herein.

With reference to Figure 1, reference numeral 1 indicates, as a whole, a ladder.

The ladder 1 comprises two vertical uprights 2 parallel to one another and a plurality of horizontal steps 3 supported by the uprights 2.

The various steps 3 are arranged crosswise between the two uprights 2 and are preferably arranged at a constant step between one another.

In the example illustrated in Figure 1, each upright 2 has a vertical longitudinal axis A and each step 3 has a horizontal longitudinal axis B.

According to the preferred embodiment illustrated in Figures from 1 to 4, each upright 2 is composed of a section bar, i.e. a bar having a constant cross-section, preferably made of metal but optionally also of plastic material.

With reference to Figures from 2 to 4, each upright 2 is formed by: a vertical outer wall P1, two vertical side walls P2 which branch off from opposite ends of the outer wall P1, and two vertical inner walls P3 which are parallel to the outer wall P1 and which branch off from the two distal ends of the side walls P2, and are arranged at a certain distance from one another. According to a different embodiment not illustrated, one single inner wall P3 is present which extends between the two distal ends of the side walls P2; i.e., in this embodiment, the two inner walls P3 are joined to one another in a seamless manner forming one single inner wall P3.

According to the preferred embodiment illustrated in Figures 2, 3 or 4, each upright 2 is provided with two vertical wings P4, which branch off from the two distal ends of the inner walls P3 and are parallel to the side walls P2.

According to the invention illustrated in Figure 5, each step 3 is made by means of a constant C-shaped cross-section bar, preferably made of metal but optionally also of plastic material; each step 3 has a horizontal upper wall P5 and two vertical side walls P6 (thus parallel to the side walls P2 of the uprights 2) which branch off from opposite ends of the upper wall P5.

According to the invention illustrated in Figure 3, each upright 2 is provided with a plurality of outer holes 4, made on the outer wall P1, which enable the insertion of the steps 3 therein.

Preferably, the outer holes 4 have a shape that reproduces in negative and by excess the cross-section (i.e. orthogonal to the longitudinal axis B) of each step 3.

According to the invention illustrated in Figure 3 each outer hole 4 is further provided with a tongue 7, which branches off from the lower side L1 of each outer hole 4 and is adapted to prevent the accidental slipping out of the step 3, once bent, after having completed the interlocking between each step 3 and the two uprights 2.

Each tongue 7 is initially parallel to the outer wall P1 of each upright 2; each tongue 7 is then bent by 90° with respect to the corresponding outer wall P1, so as to be in abutment against the upper wall P5 of the relative step 3, once completely assembled.

Furthermore, each tongue 7 is preferably provided with a hole 8, adapted to facilitate the bending operation of the tongue 7, favouring the deformation of each tongue 7 in the ideal point.

According to the preferred embodiment illustrated in Figure 4, the inner walls P3 and the wings P4 of each upright 2 are provided with inner holes 5 (open on one side, i.e. through holes, slots) which enable the insertion of the step 3 therein.

Preferably, each inner hole 5, made on the inner walls P3 and on the wings P4, is arranged at a height such that, once completely assembled, the upper wall P5 of the corresponding step 3 is at the same height of the lower side L1 of the outer hole 4 of each upright 2, as illustrated in Figure 2.

Preferably, each inner hole 5 is made in such a manner that the distance between the two vertical profiles L2 and L3 obtained on the inner walls P3 of each upright 2 is equal to the width of each step 3, so as to prevent the translation of the step 3 in a longitudinal direction, orthogonal to the plane defined by the longitudinal axis A of each upright 2 and to the longitudinal axis B of each step 3, once completed the interlocking between the components.

It is understood that the section bar of each upright 2 could have a closed section (i.e. could have one single inner wall P3 which extends between the two distal ends of the side walls P2) and thus the inner holes 5 could be closed.

According to the invention illustrated in Figure 5, both side walls P6 of each step 3 are provided with two vertical slits 6 at their ends, adapted to enable the insertion and the interlocking of each step 3 with the inner walls P3 of each upright 2.

Preferably, the slits 6 made on the side walls P6 of each step 3 have a toothed profile, as illustrated in Figure 5; furthermore, the slits 6 made on the side walls P6 of each step 3 are press-fitted into the inner walls P3 of each upright 2.

Preferably, each slit 6 is made at a distance, measured parallel to the longitudinal axis B, from the corresponding end of each step 3, such that the end of each step 3 is in abutment against the inner surface of the outer wall P1 of each upright 2, once completely assembled.

Preferably, each section bar 6 is made at a distance, measured parallel to the longitudinal axis B, from the corresponding end of each step 3, such that the end of each step 3 presses against the corresponding inner wall P3, further away from the outer wall P1, thus causing a deformation of the inner wall P3.

The present invention further relates to an assembly kit for the ladder 1, wherein the steps 3 and the two uprights 2 are disassembled.

The present invention further relates to an assembly method of the assembly kit for the ladder 1.

The assembly method provides for arranging the two uprights 2 parallel to one another and spaced by a distance D equal to the length (longitudinal dimension) of each step 3, then for inserting each step 3 through a corresponding outer hole 4 of an upright 2 until reaching and engaging a corresponding outer hole 4 of the other upright 2, and lastly for interlocking each step 3 with the inner walls P3 of the two uprights 2 at the slits 6. Once carried out the interlockings of each step 3 with the inner walls P3 of the two uprights 2, the tongues 7 are bent inwards (with a plastic deformation of the material) until they are brought into abutment against the respective steps 3.

The ladder 1 described above has numerous advantages.

Firstly, the ladder 1 described above can be transported, stored and delivered disassembled thus occupying a minimum space (if compared to the space occupied by the assembled ladder 2).

Furthermore, the ladder 1 described above can be assembled by the end user in a simple (thus without requiring particular manual skills), intuitive (thus without requiring particular training), quick manner, and without requiring particular tools at disposal (if not a common hammer).

Lastly, the ladder 1 described above is of simple and cost-effective production since the uprights 2 and the steps 3 are easy to manufacture by means of the square bending (i.e. by 90°) of corresponding sheared flat plates.

1

ladder

2

uprights

3

steps

4

outer holes

5

inner holes

6

slits

7

tongue

8

hole

L1

lower side

L2

left side of inner hole

L3

right side of inner hole

A

longitudinal axis

B

longitudinal axis

P1

outer walls

P2

side walls

P3

inner walls

P4

wings

P5

upper walls

P6

side walls