EP0331098B1 - Ladder - Google Patents

Abstract

A ladder (10) has rails (11) and wide rungs (12). The wide rungs (12) are designed as C profiles which are open at the bottom and have a treading surface (16) which is protected against slipping. The rails (11) in the traction zone have either a simple, correspondingly dimensioned limb or a box profile which increases the moment of resistance. In this case, it is possible for identical wide rungs (12) to be employed in ladders of different design. An optimised modular production can be provided. <IMAGE>

Description

The invention relates to a modular ladder system from which ladders can be assembled, the spars and rungs of which are formed from thin-walled metal profiles which are connected to one another by rivets, welding or the like, and wherein the spar profile is an external web and has integrally attached front legs and rear legs pointing towards the other spar.

A distinction is made between step and rung ladders. Rung ladders are installed or installed at angles from 65 ° to 75 ° and step ladders at angles from 60 ° to 70 °. Rungs are calculated up to a step depth of 80 mm. In practice, however, rungs are only 20 to a maximum of 60 mm wide.

In the case of step ladders and stairs, it is already known to insert the profile parts adapted to the respective purpose for the steps, mostly light metal extruded profile parts, between inwardly open U-profiles or C-profiles of the spars and to fasten them therein.

From DE-GM 71 28 163 a step ladder is known in which the steps are fastened between the inwardly open profiles of the side rails. To fasten the steps, incisions corresponding to the profile of the steps are provided in the inner legs of the cross-section C-shaped side rails, into which the steps are inserted and connected to the rails by spot welding. The making of the incisions is extremely complex and shows that one has not recognized, by sensible design of the spar cross-sections, to increase their section modulus so that flat spar surfaces for the attachment of the steps can also be achieved by spot welding, riveting, clinching or the like. creates.

From DE-GM 73 12 308 a metal ladder, in particular an aluminum ladder, has become known, in which the spars, seen in cross section, consist of three self-contained, coherent chambers formed by the metal walls, with the rungs on or in the middle chamber are used. The height of one outer chamber can be greater than the height of the other outer chamber in order to facilitate the nesting of the conductors without the stability of the bars being impaired. Furthermore, the middle chamber can be formed by recessed webs, so that the rungs can be inserted and welded more easily. The spars are obviously always the same and designed for certain rungs and ladders, so that this solution does not improve series production of ladders with different loads. The closed box profiles require the rungs to be welded on because there are no contact surfaces and access options for point fixings, such as rivets or clinching.

From DE-GM 72 40 786 a metal rung ladder is known, which also consists of aluminum and on the one hand shows spars made of rectangular, longitudinally open aluminum profiles with inwardly angled flanges, and on the flanges mentioned that made of aluminum profiles existing rungs are welded. An outside depression can be provided for stiffening and the flanges can extend as far as the depression in order to achieve an additional lattice girder effect. The result is approximately the same box-shaped profiles as in the aforementioned construction. This ladder is also designed for welding and does not provide that, in order to improve the manufacture of ladders with different loads, the same rungs but corresponding, differently designed bars are used. The rungs can be diamond-shaped. The rungs are relatively narrow and therefore have the problems of the usual rung ladders.

From DE-GM 77 37 792 a rung of about 30 x 30 mm square box profile is known, which has a vertical transverse wall and an inner screw channel to allow screws from the outside for fastening in wooden or aluminum bars. The entire rung profile is designed as a light metal extrusion. From the drawing it can be seen that the top and bottom are slightly curved and provided with longitudinal ribs. It is not possible to connect the front legs and the rear legs of bars that extend laterally across the rung because the square box profile, which is closed on all sides, is not easy to get into with the connecting tools, especially since the usual small rung of only 30 mm in size is also suitable for others simple routing and is not intended for optimized wide rung ladders.

The German utility model 1 768 014 deals with steps for ladders in which triangular ribs are provided on the treads, which are interrupted by rib-free surfaces. From the drawing it can be seen that the profiles of the steps are C-shaped and open at the bottom and with edge reinforcements. Fixings with bars and suitable adaptation to ladders that are not to be used as step ladders but as rung ladders are not covered. Because of the relatively large width to the height and the lack of curvature, they cannot be used as universal steps.

A ladder is known from German utility model 74 38 125, in which light metal bars between the inwardly directed edge profiles have separately formed webs which are spaced apart from one another. The rungs are welded between them. An attempt is always made to arrange the relatively narrow rungs in the center with the corresponding material accumulation in the area of the rung attachment. This accumulation of material does not optimally benefit the section modulus of the spars for the bending load.

A step ladder is known from US Pat. No. 4,655,320, in which C-shaped steps, which are open at the bottom, bear against the inner walls of the inwardly open spar profiles and are welded on. The front leg of the steps is longer or higher than the rear leg to improve the conditions for automatic welding. It has not been seen that the use of the ladder is made worse because the foot entry space is reduced. No measures have been taken or aspects are apparent for conductors with different loads.

A standing and single ladder with riveted rungs is known from DE-GM 73 01 574. Notched tube ends of the ladder rungs are guided through receiving holes in the webs of the spar profiles and riveted from the outside. This minimizes the weakening of the bars of the bars. Double-T profiles, U-profiles or rectangular tube profiles can be considered as spar profiles, although no suitable solution method is specified for the latter. No information is given or suggestions are given for the sensible cross-sectional design of spars with different load capacities and the attachment of C-shaped wide rungs that are open at the bottom.

The mass of the ladder has relatively thin rungs inserted into the spar profile and provided with a small tread, for a simple reason. While the step ladder or staircase can obviously only be installed in one direction and cannot be used in the other direction of installation, the rung ladder is designed symmetrically so that the direction of adjustment is not important. Accordingly, both outer areas of the spars must be designed so that they can be considered as tension zones and that the rungs or steps can be arranged centrally in the spars.

From FR-A-2 356 801 ladders are known which are composed of bars and rungs. Relatively thin, cylindrical round rungs or round rungs with flat tread surfaces and downwardly projecting legs are connected to the spars. The spars have profiles that are oriented for fastening to the dimensions of the round rungs or the round supporting parts of the rungs with flat treads. The rungs pass through the spar walls or they are equipped with other round connecting means that extend through the spar walls. A larger number of different spar profiles is presented, in which box-like spar reinforcements with the same size cross section are also provided on both sides of the round central connection. A box profile can also be attached to a C-profile be molded, the special thing is that the box profile is about the same size, even if the profile receiving the rungs has a different size. With such ladder concepts, a different ladder-spar basic cross-section is required for each rung size and the production rationalization cannot be based on a broad rung intended for ladders of different lengths and different loads, which can be based on the safety requirements during use.

If you want to produce ladders of different lengths, in which the steps are inserted between the legs of the C-profiles forming the spars, spars of different widths and steps corresponding to the depth of step are generally used. That means a lot of effort.

For ladders with rungs inserted in the middle, several, e.g. T. complicated operations required for assembly.

In the case of step ladders and rung ladders, it is customary to provide corner braces which, as a rule, protrude at least somewhat into the step space to be kept as free as possible for the feet.

The lateral stiffness and torsional stiffness of the spar profiles must also be taken into account, particularly with longer conductors.

Although ladders have been manufactured for a very long time, there is still a need to optimize manufacturing and usage conditions.

Accordingly, the invention is based on the object of proposing a ladder concept which allows the same rungs to be used in modular construction with a relatively large tread depth for different spar cross-sections, and in which the spar cross-sections can nevertheless be readily adapted to the respective strength requirements.

Accordingly, the invention provides a modular ladder system, from which ladders can be assembled, in order to optimize production, create modular construction and warehousing and to enable other rationalization measures.

Using the partial features already listed above for the introduction of the general description part, the invention as a whole is defined by the following features:
Modular ladder system from which ladders can be assembled, the spars and rungs of which are formed from thin-walled metal profiles which are connected to one another by rivets, welding or the like, and wherein the spar profile is an external web and attached to it in one piece , has front legs and rear legs pointing in the direction of the other spar, and the rungs as wide rungs with the same size, which are the same size for different conductors, and which are open to the bottom and have a lying C profile
Tread depth of at least 45 mm are formed, the
Front legs rest directly on the inner walls of the straight front legs of the spars, which are the same for different conductors
and where
the distance between the front leg and rear leg or, if appropriate, between the front leg and a rung contact wall formed on the web corresponds to the width of the rungs
and where
the rear legs of the spars have a cross-sectional design and / or extension corresponding to the load conditions in the direction of the spar axis and corresponding strength requirements of conductors of different lengths and different loads.

By using broad rungs, i.e. rungs with appropriate tread depths of 35, 40, 50 or 60 mm for the use, but not using the deeper steps, which are not necessary for many purposes, the overall weight of the ladder can be significantly reduced, even with long lengths. By dimensioning the cross-section of the spar only in those places where it is actually necessary to absorb the forces in such a way that it can absorb them, but otherwise only executes them in dimensions such as those required for bending stress, torsional rigidity and Rung attachment is absolutely necessary and arranges the material accumulations where they are not disruptive when climbing and handling, you can significantly reduce the amount of material used and thus the weight, and also improve the torsional rigidity of the ladder.

Since you can also design a ladder program with certain usage lengths and for certain types of use with wide rungs suitably designed in the above-mentioned range, the total weight of especially long ladders is considerably reduced, which is particularly important for handling during transport, installing ladders and assembly and disassembly of scaffolding and the like is of great importance and also enables a considerably cheaper production.

Since the rungs are designed as broad rungs, the installation direction is always visible to the sensible user, so that the risk that the long ladder, which is only reinforced in the pulling zone, is incorrectly applied, is relatively low. Thus, in a particularly expedient embodiment of the invention, the broad rungs can be arranged off-center in the spars, the tensile zones of which are reinforced. Within the framework of the modular program, however, the same broad rungs can be attached in the same way with the features that are dealt with in the rest, also in the middle of bars which are designed symmetrically or only with legs extended on one side. The associated advantages of the modular system, the assembly and the like are also achieved.

However, since the weight saving is particularly important for conductors of greater length, a further expedient design according to the invention provides that the tension zones of the spars are formed by box-shaped, rolled and / or folded profile parts. As a result, the amount of material required for the section modulus can be easily accommodated in the tension zone at points that do not interfere with climbing, working and handling, and still has a very cheap manufacturing option, regardless of which raw materials you want to use.

With rolled-up and / or folded profile parts, additional welding can be carried out. The box profile does not necessarily have to be completely closed, although this is expedient. The box profile has a rectangular profile in a particularly clear and easy to manufacture manner. This creates a good contact surface for inserting the broad rungs with their legs protruding downwards. However, differently shaped profiles with curves, indentations, diagonals, multiple developments and curls or the like, and multiple rectangles are also conceivable. An expedient embodiment of the spars provides that the rectangular box profile formed in tension zones of the spars has a wall box wall located in the extension of the web, an inner wall offset inward from it at a distance, and a rung system wall connected at right angles thereto and a wall running parallel to and at a distance from it Has outer wall.

With a simpler design and corresponding requirements, only the rear legs of the bars located in the tension zones can be wider than the front legs. This also improves the possibilities of riveting.

To reinforce and protect the smooth surfaces, the edges of the spars can be designed with preferably partially cylindrical corner ribs.

Since the conductors have broad rungs and can be used with different angles of attack, it is expedient if the tread surfaces of the broad rungs are slightly arched upwards, preferably partially cylindrical, with anti-slip ribs. Then they offer favorable appearance options for the user in every possible angular position.

Since equally deep broad rungs are to be used for different conductors, it is expedient to improve the stability if reinforcing ribs or reinforcing legs directed inward are formed on the lower edges of the vertical legs of the broad rungs. The reinforcement legs can have a greater depth extension for wider conductors and conductors with greater load capacity than for conductors with less stress. In this way, wide rungs of the same depth and height can be designed with different moments of resistance and torsional stiffness. You can also make the back legs of the rungs higher than the front legs of the same. Even so, there is a possibility for a sensible distribution of the materials and possibly for improving the riveting.

You can also make the rear legs of the broad rungs taller than their front legs. This also improves riveting and sensibly distributes the material.

So that the user notices when the ladder is erected incorrectly that he has to turn it over for safety reasons, one expediently provides that the profiles of the treads of the broad rungs in the rear area are conspicuously designed when they occur. Since one usually gets up relatively far forward on the broad rung with the ball of the foot, it is sufficient if the toe area notices an increase that the ladder is standing correctly. However, if the user climbs on a sharp pointed edge, for example, he will notice that the ladder is standing incorrectly due to the unfavorable support of his weight. For this purpose, the rear edge of the tread surface of the broad rung can have a tip formed on it.

The conductors can be made in whole or in part from all the metals in question, in particular the spars and / or the broad rungs can be formed from extruded light metal profiles. Profiling is then possible in a wide range and you get corrosion protection by yourself. In many cases, however Advantages to achieve when the spars and / or broad rungs are formed from corrosion-protected sheet steel parts and / or light metal sheet parts. With the appropriate selection and composition of materials, taking into account the profile suggestions made above, the optimal combination within the framework of the modular system can be realized simply and inexpensively in order to make the ladder as user-friendly as possible.

Broad rungs and spars can also be connected in an advantageous manner by means of clinching connections. Special attention should also be paid to the angular stability of the ladder, especially if the broad rungs are not welded but riveted. For this purpose, stiffening angles are provided in at least individual corners of the ladder between the spars and broad rungs, the leg width of which corresponds to the inner leg width of the broad rungs in which they are inserted. The stiffening brackets are connected to the rungs and the spars at a stable angle, preferably riveted. Depending on the design of the ladder, such insertion angles, which are no longer visible and no longer impede the entry areas, only need to be inserted at different points and are then connected in a suitable manner, preferably at least partially riveted to the rung attachment. The stiffening angles are expediently formed as flat angle parts in the manner of window frame angles. So they only need to be punched out and offer great stability in the corner. The leg of the stiffening angle lying in the rung can be longer than the front leg or rear leg of the associated spar. So he stands hidden over it and the lever arms can be extended. Depending on the requirements, the stiffening angles can be unequal or, in particular, isosceles. The broad rung can also be riveted to the easily accessible front leg of the respective spar and welded to the square profile of the rear leg of the respective spar. Further details, configurations, features, advantages and aspects of the invention are also dealt with in the following description part, which is dealt with on the basis of the drawings.

Embodiments of the invention are described below with reference to the drawings.

Fig. 1

Die Schrägansicht von oben auf eine Ecke einer Leiter, bei der eine Breitsprosse in einem Cförmigen Holm eingenietet ist;

Fig. 2

eine Schrägansicht auf die Anordnung nach Fig. 1, jedoch schräg von unten mit Darstellung des Versteifungswinkels;

Fig. 3

eine der Fig. 1 entsprechende Darstellung einer ersten Ausführungsvariante aus dem zusammengehörigen Leiternprogramm nach dem ersten Ausführungsbeispiel wobei der Hinter-Schenkel des Holmes in der Zugzone durch ein Kastenprofil verstärkt ist;

Fig. 4

eine der Fig. 2 entsprechende Darstellung der Lösung nach Fig. 3 schräg von unten;

Fig. 5

einen Holmquerschnitt für die Ausführungsvariante nach den Figuren 1 und 2;

Fig. 6 und 7

Holmquerschnitte für die Ausführungsvariante nach Fig. 3 und 4;

Fig. 8

eine der Fig. 1 entsprechende Darstellung der ersten Ausführungsvariante des zusammengehörigen Leiternprogramms des zweiten Ausführungsbeispieles;

Fig. 9

eine der Fig. 2 entsprechende Darstellung der Leiter nach Fig. 8;

Fig. 10

eine der Fig. 3 entsprechende Darstellung der ersten Ausführungsvariante des Leiternprogramms des zweiten Ausführungsbeispieles mit Kastenprofil hinten am Holm;

Fig. 11

eine der Fig. 4 entsprechende Darstellung des Ausschnittes einer Leiter nach Fig. 10;

Fig. 12

eine der Fig. 5 entsprechende Darstellung des Holmquerschnittes der Leiter nach den Fig. 8 und 9;

Fig. 13

eine erste Variation des Holmquerschnittes mit einem Kastenprofil;

Fig. 14

eine weitere Variation des Holmquerschnittes, wie er für die Leiter nach den Fig. 10 und 11 benutzt ist;

Fig. 15

einen Querschnitt mit der Darstellung des Profils einer ersten Variante für die Breitsprossen;

Fig. 16

eine der Fig. 15 entsprechende Darstellung einer weiteren Ausführungsvariante;

Fig. 17

eine den Fig. 15 und 16 entsprechende Darstellung einer weiteren Ausführungsvariante des Profils für die Breitsprossen und

Fig. 18

eine Darstellung einer Leiter nach der Erfindung.

Show it:

Fig. 1

The oblique view from above onto a corner of a ladder, in which a broad rung is riveted into a C-shaped spar;

Fig. 2

an oblique view of the arrangement of Figure 1, but obliquely from below showing the stiffening angle.

Fig. 3

1 a representation of a first embodiment variant from the associated ladder program according to the first exemplary embodiment, the rear leg of the spar being reinforced in the tension zone by a box profile;

Fig. 4

one of FIG 2 corresponding representation of the solution of Figure 3 obliquely from below.

Fig. 5

a spar cross-section for the embodiment variant according to Figures 1 and 2;

6 and 7

Spar cross sections for the embodiment variant according to FIGS. 3 and 4;

Fig. 8

a representation corresponding to FIG 1 of the first embodiment of the associated ladder program of the second embodiment.

Fig. 9

one of FIG 2 corresponding representation of the conductor of FIG. 8.

Fig. 10

a representation corresponding to Figure 3 of the first embodiment of the ladder program of the second embodiment with box profile at the rear of the spar;

Fig. 11

one of the 4 corresponding representation of the section of a ladder of FIG. 10;

Fig. 12

5 a representation of the cross-section of the ladder according to FIGS. 8 and 9;

Fig. 13

a first variation of the spar cross section with a box profile;

Fig. 14

a further variation of the cross-section of the spar, as used for the ladder according to FIGS. 10 and 11;

Fig. 15

a cross section showing the profile of a first variant for the broad rungs;

Fig. 16

a representation of another embodiment variant corresponding to FIG. 15;

Fig. 17

15 and 16 corresponding representation of a further embodiment of the profile for the broad rungs and

Fig. 18

an illustration of a ladder according to the invention.

The first embodiment, which comprises three design variants belonging to a ladder program, is shown in FIGS. 1 to 7 and is initially dealt with in a coherent manner with the basic points of variation.

A ladder 10 consists of two spars 11 and broad rungs 12 attached therebetween. The broad rungs 12 have a C profile which is open at the bottom and has an entrance wall 13, a front leg 14 and a rear leg 15. They are made from extruded aluminum -Profil or from folded sheet metal profile made of light metal or galvanized steel sheet or the like. The upper tread surface 16 is equipped with anti-slip ribs 17. On the trailing edge 18, a raised tip or other profiling, not yet shown, can be provided. The tread depth T of the broad rungs 12 is at least 35 mm, but preferably approximately 40-50 mm. As a result, they ensure a secure stand and, above all, satisfy the special purpose that wide rungs 12 of the same profile can always be used with a wide variety of ladders with different spars and different lengths.

The spars 11 here consist of an inwardly open C-profile with an outer web 20, a front leg 21 and a rear leg 22. These can either be the same width or it can be useful - as can be seen in FIG. 5 - the rear leg 22 should be somewhat wider, so that the larger amount of material runs in the pull zone and the forces are absorbed cheaply.

Such a simple C-profile for ladder stiles is known per se. It is also known to interpose levels. However, the aim here is to show, in the context of the optimization of a modular production, that the same broad rungs can also be used in such known, simple C-profile spars that are open inwards. However, the previously known C-profiles have the same front leg and rear leg. According to the invention, the rear leg can advantageously be equipped with a larger material cross section.

The steps are expediently fastened by rivets 23 which are guided in a known manner through the legs of spars and broad rungs.

It can be useful - as can be seen in particular from FIG. 2 - to provide a stiffening angle 25 which has two legs 24.1 and 24.2. These have a width that is less than the height or width of the front leg 14. They are of a suitable length. The horizontal legs 24. 1 are covered by the front legs 14 and protrude beyond the front legs 21, so that there is still a rivet point 26 which does not extend through the cross-section of the spar, but extends the length of the holding lever. Another rivet point 27 is only in the front leg 21 of the spar profile and also offers one here Good support base for the vertical leg 24.2 of the stiffening angle 25, which projects downward in the spar. The rivet in the corner point 28 connects the spar 11, wide rung 12 and stiffening angle 25. Thus, the connection between spars, wide rungs and stiffening angles can be made with a few rivet points. It should be taken into account that the stiffening angle, on the one hand, is easy to produce because of its flat, simply punched-out design and, on the other hand, has great stability and that the riveting does not result in any heat loads on the profiles which may be made of light metal, which would reduce their strength. In addition, the rivet connection can be made inexpensively in large numbers. Bracing angles need not be used in every step. Depending on the length of the ladder, they are to be distributed over the length.

Instead of a rivet connection using punched holes and inserted rivets, in which only the material of the rivets is deformed, other point-like joint connections, such as screws, can also be used. Depending on the material, spot-weld connections or the like can be used. A particularly advantageous possibility for the point-like connection of the materials to be processed for conductors, such as rolled or bent steel profiles or extruded light metal profiles, consists in the use of clinching connections. Suitable matrices and stamps are used to press the material of one flat part into a recess in the immediately adjacent other part, so that the components are positively connected to one another by permanent deformation of their materials. Such connections can be used like conventional riveted connections at the locations designated by 23, 26, 27, 28, 28.1, 28.2 and indicated by dots. As a rule, the same or similar materials with very related material properties, such as light metal bars and light metal rungs, will preferably be connected to one another by means of clinching connections. However, steel and light metal can also be connected to one another with suitable design of the clinching connections with regard to dimensions and tools.

3 and 4, the same parts are provided with the same reference numerals. The rear leg is designed here according to the invention in a special embodiment as a box profile 32 so that the web 20 has a web box wall 20.1 in a linear extension and the rear leg is formed with a rung contact wall 33 which is the rear leg 22 of the first ladder configuration with regard to the installation and fastening of the broad rung, but not only with regard to the load capacity. An outer wall 34 lies at a distance A 2 from the rung contact wall 33 shown in FIG. 7. Both are connected via the inner wall 35. It can this box section 32 can be formed by folding alone, by folding and welding together in the corner 36 or as a light metal extrusion profile. It clearly has a much greater section modulus than a simple leg and can thus help to design a long, yet rigid and quite well torsion-resistant ladder in a simple manner, with the same broad rungs resting on a straight surface, namely the rung contact wall 33 and with the aid of a suitable one Fastener are attached. Screwing in a screw from the inside or through a bore 38 in the outer wall 34 is an option, it being possible to cover the bore 38 with a cap if so desired.

By having a box section 32 in the pull zone, the ladder can be optimized considerably with regard to the use of material, weight and use.

6 and 7 illustrate that the distances A 1 and A 2 can be different and thus the section modulus - depending on the needs with regard to bending and torsional strength - can be made larger or smaller, with the same spaces between the front leg 21 and rungs System wall 33 for the broad rungs 12 remain so that the wide rungs 12 optimized for use can be used for a wide range of conductors. Also on this broad rung is expediently provided with a tip or the like clarifying the direction of adjustment at the rear. By varying the material cross-sections and the leg lengths and box sizes, it is very easy to adapt to the respective needs for smaller, larger, wider, longer, lighter or heavier conductors and can all equip them with stiffening angles in the same way.

The embodiment of FIGS. 8 to 17 corresponds in its basic structure to the first embodiment with its design variants. Accordingly, the same parts are provided with the same reference numerals. Only the shape of the profiles is slightly varied, both with regard to the dimensions as well as the edge designs and corner designs. Only these deviations are described below.

The cross section of the spars 11.1 always has the same width of the front leg 21 and the rear leg 22. However, partially cylindrical corner ribs 40.1 to 40.4 are provided on all longitudinal edges of the spars 11. On the one hand, these improve stability and make the profile more comfortable to hold. To a certain extent, they also prevent scratching smooth surfaces when they are placed against one another and the like.

To connect the broad rungs 12.1 with the spars 11.1, two rivets 28.1 and 28.2 are provided in the variant according to FIGS. 10 and 11.

The wide rungs 12.1 are shown in FIGS. 8 to 11 with relatively low front leg 14.1 and rear leg 15.1. They have partially cylindrical reinforcing ribs 45 on their lower edges.

The broad rungs according to FIGS. 8 to 11 correspond approximately to the profile of FIG. 15, only in the latter the legs are somewhat higher.

In both the tread surface 16 is arched upwards and has the anti-slip ribs 17 and on the rear edge 46 a clearly protruding pointed rib 47, while the front tread edge 48 is slightly rounded. This means that when you step with your foot, you notice which side of the broad rung you are standing on and whether the ladder is placed the wrong way round.

To further reinforce the broad rungs, reinforcement legs 50.1 and 50.2 can be provided on the lower edges of front leg 14.1 and rear leg 15.1. 16 have a relatively small width and increase the section modulus accordingly. In the embodiment variant according to FIG. 17, the reinforcement angles 50.3 and 50.4 are designed with a greater width, so that the section modulus is increased accordingly without the step space would be hindered. This allows you to produce wider rungs with an otherwise slim profile. All of these profile parts are made of extruded aluminum profile and are only cut, joined and riveted. They can also be at least partially welded.

Fig. 18 shows an entire ladder in which the profile parts described above are used. Other conductor shapes can also be formed in the manner according to the invention.

The summary printed below is part of the disclosure of the invention:
A ladder (10) has bars (11) and broad rungs (12). The wide rungs (12) are designed as C-profiles which are open at the bottom and have a non-slip tread (16). The spars (11) have either a simple, appropriately dimensioned leg in the tension zone or a box profile which increases the section modulus. The same broad rungs (12) can be used for differently designed ladders. An optimized modular production can be created

Reference symbol list:

10th

ladder

11

Spar

11.1

Spar

12

Broad rungs

12.1

Broad rungs

13

Step wall

14.

Front leg

14.1

Front leg

15.

Back leg

15.1

Back leg

16

Tread

17th

Anti-slip rib

18th

Trailing edge

20th

web

20.1

Dock wall

21

Front thigh

22

Hind legs

23

rivet

24.1

Horizontal leg

24.2

Vertical leg

25th

Stiffening angle

26

Rivet point

27

Rivet point

28

Corner point

28.1

rivet

28.2

rivet

32

Rear leg / box profile

33

Rung system wall

34

Outer wall

35

Interior wall

36

corner

38

drilling

40.1

Corner rib

40.2

Corner rib

40.3

Corner rib

40.4

Corner rib

45

Reinforcement rib

46

Trailing edge

47

pointed rib

48

Leading edge

50.1

Reinforcement leg

50.2

Reinforcement leg

50.3

Reinforcement leg

50.4

Reinforcement leg

T

Depth of appearance

A1

Distance / dimension

A2

Distance / dimension

Claims (17)

1. Modular ladder system from which ladders (10) can be assembled whose longitudinal members (11; 11.1) and rungs (12, 12.1) are made of thin-walled metal sections connected to to one another by rivetting, welding or the like, and wherein the longitudinal member section comprises an external web (20) and front (21) and rear (22) flanges joined integrally thereto and directed in the direction towards the other longitudinal member, and wherein the rungs are constructed as downwardly open wide rungs (12; 12.1) having a tread surface depth (T) of at least 45 mm which have a cross-section in the form of a lying C and are of the same size for different ladders, and whose front flanges (14; 14.1) abut directly on the inner walls of the straight front flanges (21) of the longitudinal members (11; 11.1), which latter flanges are identical for different ladders, and wherein the spacing between the front flange (21) and rear flange (22) or where appropriate between the front flange (21) and a rung abutment wall (33) formed on the web (20) corresponds to the width of the rungs (12), and wherein the rear flanges (22; 32) of the longitudinal members (11, 11.1) have a cross-sectional form and/or extent appropriate to the load circumstances in the direction of the longitudinal member axis and corresponding strength needs of ladders (10) which are of different lengths and are to accept different loads.
2. Ladder using the modular ladder system according to claim 1, characterised in that the wide rungs (12; 12.1) are arranged eccentrically in the longitudinal members (11; 11.1), and the tension zones (22,32) thereof are reinforced.
3. Ladder using the modular ladder system according to claim 1 or 2, characterised in that the tension zones of the longitudinal members (11; 11.1) are formed of box-shaped, rolled-in and/or bent-over section parts (32).
4. Ladder using the modular ladder system according to claim 3, characterised in that the box section (32) is a rectangular section.
5. Ladder using the modular ladder system according to claim 4, characterised in that the rectangular box section (32) formed in tension zones of the longitudinal members (11; 11.1) comprises a web box wall (20.1) situated in prolongation of the web (20), an inner wall (35) situated inwardly offset at a spacing relatively thereto, and a rung abutment wall (33) joined thereto at right angles, and an outer wall (34) disposed parallel thereto and at a spacing (A 1; A 2).
6. Ladder using the modular ladder system according to claim 1 or 2, characterised in that the rear flanges (22) of the longitudinal members (11), which are situated in the tension zones, are wider than the front flanges (21).
7. Ladder using the modular ladder system according to at least one of claims 1 to 6, characterised in that the edges of the longitudinal members (11.1) are provided with corner ribs (40.1 to 40.4) preferably of part-cylinder shape.
8. Ladder using the modular ladder system according to at least one of claims 1 to 7, characterised in that the tread surfaces (16) of the wide rungs (12.1) are given a shape which is slightly upwardly arched and preferably similar to part of a cylinder, with slip-obviating ribs (17).
9. Ladder using the modular ladder system according to at least one of claims 1 to 8, characterised in that reinforcing ribs (45) or inwardly directed reinforcing flanges (50.1 to 50.4) are formed on the lower edges of the vertical flanges (14.1; 15.1) of the wide rungs (12.1).
10. Ladder using the modular ladder system according to at least one of claims 1 to 9, characterised in that the rear flanges (15) of the wide rungs (12; 12.1) are higher than the front flanges (14).
11. Ladder using the modular ladder system according to at least one of claims 1 to 10, characterised in that the tread surface (16) of the wide rungs (12.1) is profiled to have a noticeable projection (47) in the rear region when the user steps-on.
12. Ladder using the modular ladder system according to claim 11, characterised in that a pointed tip (47) is formed on the rear edge (46) of the tread surface (16) of the wide rungs (12.1).
13. Ladder using the modular ladder system according to at least one of claims 1 to 12, characterised in that longitudinal members (11; 11.1) and/or wide rungs (12; 12.1) are formed from light metal extruded sections.
14. Ladder using the modular ladder system according to at least one of claims 1 to 12, characterised in that longitudinal members (11; 11.1) and/or wide rungs (12; 12.1) are formed from corrosion-protected sheet steel parts and/or light metal sheet parts.
15. Ladder using the modular ladder system according to at least one of claims 1 to 14, characterised in that the longitudinal members (11; 11.1) and the wide rungs (12; 12.1) are connected at the connection points (23, 26, 27, 28, 28.1 28.2) by means of forced-penetration joints.
16. Ladder using the modular ladder system according to at least one of claims 1 to 15, characterised in that in at least individual corners of the ladder there are provided between longitudinal members (11; 11.1) and wide rungs (12; 12.1) reinforcing angle elements (25) whose leg width corresponds to the inner flange width of the wide rungs (12; 12.1) into which they are placed, and the reinforcing angle elements (25) are connected so as to be angularly stable, preferably by rivetting, to the wide rungs (12; 12.1) and the longitudinal members (11; 11.1).
17. Ladder using the modular ladder system according to claim 16, characterised in that the reinforcing angle elements (25) are formed as flat angle pieces in the manner of window frame angles.

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