EP2845988B1 - Ladder provided with a tongue-and-groove reinforcement device - Google Patents

Description

The invention relates to the field of ladders, steps, stepladders, U-section uprights, and more particularly to devices for strengthening the structure thereof.

Ladders, steps, uprights with U-section uprights have the advantage of lightness, compared to ladders, step, stepladders with closed-section uprights (typically rectangular). But these ladders, steps, stepladders have the disadvantage of insufficient rigidity, because of the open profiles used, it is necessary to strengthen.

Document is known US 4,949,811 a ladder provided with u-section uprights and steps, and also provided with squaring brackets mounted at the junction between the steps and the uprights to stiffen the assembly.

In practice, it is found that this type of assembly does not go without inconvenience. More specifically, it is found that the torsional rigidity, at the interface between the step and the console, is insufficient.

A goal is therefore to provide a ladder with reinforcements designed to have increased torsional stiffness.

For this purpose, a scale according to claim 1 is proposed.

The reinforcement device of this ladder makes it possible to improve the scalability of the shear forces to which the step is subjected in use, at its interface with the uprights.

• la languette est formée en saillie à partir d'une face inférieure d'une âme de la marche ;
• la console comprend un boîtier propre à venir s'emboîter dans la marche, la rainure étant formée en creux dans une paroi supérieure du boîtier ;
• la console comprend un étai reliant le boîtier au montant ;
• l'étai présente une extrémité supérieure fixée au boîtier, et une extrémité inférieure fixée au montant ;
• l'extrémité supérieure de l'étai est munie d'une échancrure emboîtée sur la languette ;
• la console se présente sous forme d'une pièce monobloc comprenant une paroi supérieure dans laquelle est formée la rainure, et deux parois latérales sensiblement triangulaires fixées à la marche et au montant ;
• la console se présente sous forme d'une pièce monobloc comprenant une paroi supérieure sur un bord libre de laquelle est formée la rainure, et une paroi latérale sensiblement triangulaire fixée à la marche et au montant ;
• en variante, la languette est formée en saillie à partir d'une face interne d'un rebord de la marche, la console présentant une section supérieure dans laquelle est creusée la rainure ;
• la marche présente une lèvre qui s'étend en regard du rebord, propre avec celui-ci à enserrer la section supérieure de la console.

Various additional features may be provided, alone or in combination:

• the tongue is projecting from a lower face of a walking core;
• the console comprises a clean housing to fit into the step, the groove being recessed in an upper wall of the housing;
• the console includes a forestay connecting the housing to the amount;
• the strut has an upper end attached to the housing, and a lower end attached to the upright;
• the upper end of the strut is provided with a notch fitted on the tongue;
• the console is in the form of a single piece comprising an upper wall in which is formed the groove, and two substantially triangular side walls fixed to the step and the amount;
• the console is in the form of a one-piece piece comprising an upper wall on a free edge of which is formed the groove, and a substantially triangular side wall attached to the step and the amount;
• alternatively, the tongue is formed protruding from an inner face of a rim of the step, the bracket having an upper section in which is hollowed the groove;
• the step has a lip that extends opposite the rim clean with it to grip the upper section of the console.

• la figure 1 est une vue en perspective, de dessous, montrant une échelle munie de consoles d'équerrage selon un premier, un deuxième et un troisième mode de réalisation, dont les détails respectifs sont montrés en médaillons ;
• la figure 2 est une vue en coupe d'une marche et d'une console de l'échelle de la figure 1 ;
• la figure 3 est une vue en perspective de dessous montrant une échelle munie de consoles d'équerrage selon un quatrième et un cinquième mode de réalisation, dont les détails respectifs sont montrés en médaillons ;
• la figure 4 est une vue de détail en perspective montrant une échelle munie d'une console d'équerrage, selon un sixième mode de réalisation ;
• la figure 5 est une vue partielle en section, selon le plan de coupe V-V de la figure 4 ;
• la figure 6 est une vue de détail en perspective montrant une échelle munie d'une console d'équerrage, selon un septième mode de réalisation ;
• la figure 7 est une vue partielle en section, selon le plan de coupe VII-VII de la figure 6 ;
• la figure 8 est une vue de détail en perspective montrant une échelle munie d'une console d'équerrage, selon un huitième mode de réalisation ;
• la figure 9 est une vue partielle en section, selon le plan de coupe IX-IX de la figure 8.

Other objects and advantages of the invention will become apparent in the light of the description of embodiments, given below with reference to the accompanying drawings in which:

• the figure 1 is a perspective view, from below, showing a ladder provided with squaring brackets according to a first, a second and a third embodiment, the respective details of which are shown in medallions;
• the figure 2 is a sectional view of a step and a console of the scale of the figure 1 ;
• the figure 3 is a perspective view from below showing a ladder provided with squaring brackets according to a fourth and a fifth embodiment, the respective details of which are shown in medallions;
• the figure 4 is a detailed perspective view showing a ladder provided with a squaring console, according to a sixth embodiment;
• the figure 5 is a partial view in section, according to the sectional plane VV of the figure 4 ;
• the figure 6 is a detailed perspective view showing a ladder provided with a squaring console, according to a seventh embodiment;
• the figure 7 is a partial view in section, according to section plane VII-VII of the figure 6 ;
• the figure 8 is a detailed perspective view showing a ladder provided with a squaring console, according to an eighth embodiment;
• the figure 9 is a partial view in section, according to the IX-IX section plane of the figure 8 .

There is shown in the figures a scale 1. This scale 1 can be used alone or be integrated in a step or stepladder, the latter two terms can be considered synonymous. The ladder 1 comprises a rise plane 2 having a pair of uprights 3 substantially parallel or converging towards an upper end, and one or more steps 4 connecting the uprights 3 transversely .

In the examples illustrated on the figures 1 and 3 , scale 1 comprises four steps 4. Alternatively, scale 1 could include a lower number of steps (nevertheless greater than or equal to one) or greater. At lower ends, the uprights 3 are preferably provided with anti-slip pads.

The uprights 3 are formed of metal profiles (for example aluminum or aluminum alloy, or composite material, typically fiberglass or flax embedded in a thermosetting resin, in which case the uprights 3 are preferably made by pultrusion), with U section. Each upright 3 thus has a bottom wall 5 and two returns 6 at right angles.

Each step 4 has in section a U-shaped profile, and comprises a core 7 and two flanges 8 which border the core 7. As can be seen in the section of FIG. figure 2 , the flanges 8 are not necessarily at right angles to the core 7, but can extend obliquely, so that in the horizontal position of the core 7 the uprights 3 can be inclined to improve the ergonomics of the 2 climb plan. This configuration is particularly suitable for the realization of running boards.

The steps 4 are formed of metal profiles (for example aluminum or aluminum alloy).

The realization of uprights 3 and steps 4 in the form of U-section profiles is advantageous because of the weight savings achieved. However, it is necessary to consolidate the assembly, by nature less solid than that ladders and steps (or bars) section closed profile, typically assembled by bouterollage. This is why the scale 1 comprises, for each step 4, at least one squaring bracket 9 which joins each step 4 to at least one of the uprights 3 (and preferably a console 9 for each upright 3) .

In addition, in order to stiffen the assembly of the steps 4 and the uprights 3, the scale 1 comprises at least one reinforcing device 10 with a groove 11 and tongue 12 between the step 3 and the console 9.

The tongue 12 may be formed protruding on the step 4. In this case, the groove 11 is hollowed out complementary to the tongue 12 in the console 9. The first seven embodiments, illustrated in FIGS. Figures 1 to 7 , correspond to this configuration.

Conversely, the tongue 12 may be formed protruding on the bracket 9, in which case the groove 11 is hollowed out complementary to the tongue 12 in the step 4. An eighth embodiment illustrated in FIGS. Figures 8 and 9 , corresponds to this configuration.

In the first five embodiments ( Figures 1 to 3 ), the tongue 12 is formed protruding from a lower face 13 of the core 7 of the step 4.

In a first embodiment, illustrated by the top medallion on the figure 1 , the console 9 is in the form of a housing 14 having in section ( figure 2 ) a closed contour, here in the form of parallelogram. The casing 14 is of complementary shape to the step 4, in which it fits at the junction with the upright 3. The casing 14 comprises an upper wall 15 , a lower wall 16 and two lateral walls 17 which connect the latter. . As seen in the medallion and on the figure 2 , the side walls 17 are provided with rabbets 18 in which the flanges 8 of the step 4 are engaged . In addition, the groove 11 of the reinforcement device 10 is hollowed out in the upper wall 15 at the right of the tongue 12. During the engagement of the step 4 on the housing 14, the tongue 12 is housed in the groove 11, preferably with a play of a few tenths of a millimeter at most, to allow an assembly that is both easy and sufficiently rigid .

The attachment of the console 9 to the upright 3 is achieved by riveting and / or screwing. In the illustrated example, a riveting is carried out to fix together a right-angle return 6 of the upright 3, a flange 8 of the step 4 and a lateral wall 17 of the casing 14. In addition, a screw-fastening complement can be realized by means of a screw 19 which is caught in the bottom wall 5 of the upright 3 through a bore 20 projecting from the bottom wall 16 of the housing 14.

In a second embodiment, illustrated by the middle medallion on the figure 1 , the console 9 comprises not only a housing 14 as described above in the first embodiment (mounted in the same way at the junction between the step 4 and each upright 3 ), but also a strut 21 fixed a part to the housing 14 and secondly to the amount 3.

More specifically, the strut 21, which is preferably in the form of a metal strip (for example spring steel), has a body 22 which extends obliquely between the housing 14 and the upright 3, one end 23 upper integral housing 14, and a lower end 24 secured to the upright 3.

The upper end 23 , folded relative to the body 22, is fixed to the housing 14 by means of the screw 19 for fixing the housing 14 to the upright 3. In other words, the upper end 23 of the stay 21 is pinched between the head of the screw 19 and the housing 14. The lower end 24 , also folded relative to the body 22, is fixed to the bottom wall 5 of the amount 3 by screwing or, as illustrated, by riveting.

As can be seen in the medallion, the upper end 23 is provided with a notch 25 which is fitted on the tongue 12 to consolidate the assembly, and in particular to make it stiffer in torsion.

In a third embodiment, illustrated by the bottom medallion on the figure 1 , the console 9 comprises a housing 14 as described above in the first embodiment, and a strut 21 similar to that of the second embodiment. However the housing 14 is mounted not at the junction between the step 4 and the upright 3, but substantially in the center of the step 4. The fixing of the housing 14 to the step 4 is performed by means of a rivet 26 which secures each side wall 17 of the housing 14 to a flange 8 of the step 4. The or each strut 21 (in this case, two struts 21 are provided on either side of the housing 14 ) obliquely connects each end face from the housing 14 to the amount 3 opposite. The upper ends 23 of the struts 21 and the housing 14 are jointly secured by means of a screw 19 passing through the bore 20 formed in the lower wall 16 of the housing 14. The fixing of the lower ends 24 of the struts 21 to the bottom walls 5 respective amounts 3 is preferably made by riveting. As in the second embodiment, the indentations 25 of the upper ends 23 of the struts 21 are engaged, on either side of the housing 14, on the tongue 12, to the benefit of the torsional rigidity of the assembly.

In a fourth embodiment, illustrated by the bottom medallion on the figure 3 , the console 9 is in the form of a one-piece piece square, and comprises an upper wall 15 , in which is formed the groove 11 of the device 10 of reinforcement, and two substantially triangular side walls 17 , which are fixed at a time at the edges 8 of the step 4 and the returns 6 at the right angle of the upright 3 (in particular by riveting). In the example shown, the console 9 is closed by a song 27 which connects the edges of the side walls 17 .

The groove 11 comes to fit on the tongue 12, and consolidates the assembly in torsion.

In a fifth embodiment, illustrated by the top medallion on the figure 3 , the console 9 has an upper wall 15 in which is practiced the groove 11 of the reinforcing device 10 , and a substantially triangular side wall 17 , fixed to one of the flanges 8 of the step 4 (in particular by riveting). As we see on the figure 3 , the groove 11 extends on a free edge of the upper wall 17 . This configuration has the advantage of lightness and economy of material, while offering a good compromise in terms of torsional stiffness.

In a sixth embodiment, illustrated on the Figures 4 and 5 , the tongue 12 is formed protruding from an inner face of a flange 8 of the step 4.

The console 9 is reduced substantially to a metal plate having a substantially rectangular upper section 28 in which is formed the groove 11, and a lower section 29 which, as in the example shown, can have (for reasons of lightness and ergonomics) a substantially triangular outline. The bracket 9 can be fastened by riveting. A first rivet 30 thus makes the joint assembly of the step 4, a return 6 of the upright 3 and the upper section 28 of the console 9. A second rivet 31 accomplishes the assembly of the lower section 29 of the console 9 and the return 6 of the upright 3. A third rivet 32 performs the assembly of the upper section 28 of the console 9 and the rim 8 of the step 4. As can be seen on the figure 5 , the upper section 28 of the console 9 can be made rabbet with respect to the lower section 29 , to facilitate the mounting of the step 4 and properly marry the flange 8 thereof.

In a seventh embodiment, illustrated on the Figures 6 and 7 and variant of the sixth embodiment, the console 9 is similar to that of the latter. The step 4 differs by the presence of a lip 33 formed internally projecting opposite the rim 8, to grip the upper section 28 of the console 9. This lip 33, which extends from a junction between the l 7 and the rim 8, to the vicinity of the tongue 12 (but without reaching it), ensures a rigid pinching of the console 9, which allows the economy of the third rivet, as can be seen well on the figure 6 .

The eighth embodiment, illustrated on the Figures 8 and 9 , corresponds to an inversion of the sixth embodiment. The console 9 is in the form of a metal plate having a section 28 upper end provided with an inner face from which the tongue 12 is formed internally projecting, and a lower section 29 of substantially triangular shape. The groove 11 is hollowed out in an outer face of the flange 8 of the step 4. The flange 8 then extends slightly recessed relative to the core 7, a distance substantially equal to the thickness of the console 9, so as to allow the mounting thereof between the return 6 square of the upright 3 and the flange 8 of the step 4, with the tongue 12 fitted in the groove 11.

The joint fixing of the step 4, the bracket 9 and the upright 3 is preferably made by riveting, in this case by means of a pair of rivets 30, 31. A third rivet 32 also provides a complementary fastening of the upper section 28 of the console 9 on the rim 8 of the step 4.

Whatever the embodiment chosen, the reinforcement device 10 by groove 11 and tongue 12 allows to consolidate the assembly by making the on-console interface more resistant to torsional forces.

The embodiment of the tongue 12 in the form of a projecting material blade makes it possible to save material. This design also makes it possible to produce the part carrying the tongue 12 (the step 4 or the console 9 ) by spinning. Similarly, the groove 11, of small width and shallow, consumes little material and can be derived from spinning.

Claims (10)

1. Ladder (1) comprising:

   - a pair of U-section uprights (3), having a bottom wall (5) and two right-angle returns (6);

   - at least one step (4) transversely connecting the uprights (3), this step (4) having a U-section profile and having a web (7) and two flanges (8) flanking the web (7);

   - at least one squaring bracket (9) joining the step (4) to at least one of the uprights (3), each bracket (9) being fixed to a right-angle return (6) of an upright (3) and to a flange (8) of the step (4);
   and also a tongue (12) and groove (11) reinforcing device (10) between the step (4) and the bracket (9),
   this ladder being characterized in that the tongue (12) is formed by a strip of material which extends transversely as a projection from the step (4) or from the bracket (9), and in that the groove (11) is formed as a recess that complements the tongue (12) in a wall of the bracket (9) or, respectively, in a wall of the step (4), in the form of a U-shaped part of this wall of the bracket (9) or, respectively, of the step (4), this U-shaped part accepting the tongue (12).
2. Ladder (1) according to Claim 1, characterized in that the tongue (12) is formed as a projection from a lower face of a web (7) of the step (4).
3. Ladder (1) according to Claim 2, characterized in that the bracket (9) comprises a box housing (14) capable of fitting into the step (4), and in that the groove (11) is formed as a recess in an upper wall (15) of the box housing (14).
4. Ladder (1) according to Claim 3, characterized in that the bracket (9) also comprises a stay (21) connecting the box housing (14) to the upright (3).
5. Ladder (1) according to Claim 4, characterized in that the stay (21) has an upper end (23) fixed to the box housing (14) and a lower end (24) fixed to the upright (3).
6. Ladder (1) according to Claim 5, characterized in that the upper end (23) of the stay (21) is provided with a notch (25) fitted over the tongue (12).
7. Ladder (1) according to Claim 2, characterized in that the bracket (9) takes the form of a one-piece component comprising an upper wall (15) in which the groove (11) is formed, and two substantially triangular lateral walls (17) which are fixed to the step (4) and to the upright (3).
8. Ladder (1) according to Claim 2, characterized in that the bracket (9) takes the form of a one-piece component comprising an upper wall (15) on a free edge of which the groove (11) is formed, and a substantially triangular lateral wall (17) fixed to the step (4) and to the upright (3).
9. Ladder (1) according to Claim 1, characterized in that the tongue (12) is formed as a projection from an internal face of a flange (8) of the step (4), and in that the bracket (9) has an upper section (28) in which the groove (11) is hollowed.
10. Ladder (1) according to Claim 9, characterized in that the step (4) has a lip (33) extending facing the flange (8) and able with the latter to grip the upper section (28) of the bracket (9).

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