EP0928769B1 - Jib element for tower crane - Google Patents

Description

The present invention relates to the field of tower cranes and it concerns, more particularly, a lattice boom element for tower crane.

In a generally known manner, an arrow of tower crane is constituted by a succession of elements arrowheads, aligned and assembled to each other to form an arrow of the desired length. Each arrow element is a beam structure latticework, of triangular, rectangular or trapezium, which includes chords defining two at two flat faces, the chords being connected between they, in these faces, by pieces of the bar type forming a triangulation.

In the majority of existing tower cranes, lattice boom elements are made from open or closed sections of the trade, such as tubes of round or square section - see eg demand German patent 2419678. This kind of realization does not does not optimize the arrow elements, especially from the point of view of their weight and the operations of construction.

It is known, in some tower cranes, lattice boom elements of triangular section, whose triangulation is carried out from profiles of round section folded. In addition to the general inconvenience cited above, this particular embodiment presents a real difficulty of manufacture.

We also know a tower crane whose elements lattice boom are composed of a chord upper sheet metal folded, lower chords tubular made of folded sheet metal, and diagonals also in folded sheet.

Moreover, there are tower cranes that have mast elements whose ribs are made of folded sheet with a variable section over the height of these elements, at least as regards the ribs back, the triangulation of the faces of the mast elements being made by bar or tube diagonals - see French Patent 2049423 showing a decrease in steps.

By the French patent application 2478606, know another tower crane whose mast elements have a triangulation carried out by plates full, polygonal and in particular triangular or trapezoidal, these plates being joined to chords also made of folded sheet. This achievement for inconvenience an overabundance of material for the triangulation, resulting in unnecessary weight and cost high. Known variants use plates triangular or trapezoidal openwork - see patent 1560103, which corresponds to the preamble to claim 1.

It should also be noted that the known solutions for masts of tower cranes are not directly transferable to the arrows of the same cranes because the types of efforts which are subject the arrows do not match to the stress on the masts.

In consideration of prior techniques known for the realization of the arrow elements, and the where appropriate tower crane elements, the The present invention aims at providing an arrow element for tower cranes whose structure and method of obtaining allow optimization especially in terms of decrease in the weight of the element, for mechanical characteristics equal or even improved, while simplifying and streamlining manufacturing this element.

For this purpose, the present invention has essentially for object an arrow element in lattice for tower cranes, including chords defining two to two flat faces, and parts interconnecting the chords in each of these faces to form a triangulation, said parts being constituted by triangulation modules made each from a cut sheet metal and possibly folded, the boom element being characterized in that each triangulation module comprises at least two rectilinear segments connected to each other by forming at least one angle and presenting at least two free ends, this triangulation module being assembled to the frames, particularly by welding, to free ends of his segments as well as his or her corner areas.

The different segments of the modules of triangulation may be of constant section or possess, at least for some of them, a section variable on the length of the segment concerned.

Preferably, each triangulation module is made from a folded sheet according to the direction longitudinal segments of this module, or at least some of those segments, so as to constitute shaped segments in angle.

Advantageously, each triangulation module may have, at the free ends of its segments and in one or more corner regions, a cutout creating a lateral clearance, facilitating access for the welding of this module of triangulation on the frames.

Depending on the number and layout of the segments, the triangulation modules may have various configurations.

In the simplest embodiment, each triangulation module has a configuration in "V", resulting from two segments connected in one zone single angle.

According to one variant, each triangulation module has an "M" configuration, resulting from three segments connected in a common corner area.

According to another variant, each module of triangulation has a "Z" configuration, resulting in of three segments successively connected in two zones angle.

Preferably, the members of the element of arrow are, like the triangulation modules, realized from cut and folded sheets. These chords are, advantageously, of variable section over the length of the boom element and, more particularly, section decreasing from one end to the other of the chord.

Thus, an arrow element resulting from the assembly of at least three members, and series of triangulation modules arranged in different faces defined by the chords.

Since chords are, like triangulation modules, made of cut sheet metal and folded, we have great freedom of design in the choice of the shape of the upper frame (s) and lower chords, as well as the thickness of the constituent sheet.

This freedom of design also exists, well heard, for triangulation modules that can thus be adapted to the optimal recovery of efforts. In In particular, the principle of the invention makes it possible for different segments of a triangulation module, the choice a quadratic surface and quadratic moment and possibly variable, for example by realizing segments of variable section by an appropriate cut of sheet metal, or by choosing to make segments in sheet folded or not; folding here makes it possible, in particular, to vary the quadratic moment, while the form of the cutting allows in particular to distribute the material of segments of the triangulation modules so as to remove the lateral shift of the neutral fibers of these modules by relative to the neutral fiber of the frames. The principle of the invention also allows a free choice of the shape of the modules: variable angle between segments, segments of lengths and / or different sections, "V" shapes, "M" or "Z" as previously defined, adaptation of shapes and dimensions of the corner areas used for making welded connections with the members, this to solve fatigue problems and to control the eccentricities of the neutral fibers.

Note also that the entire arrow is feasible from a flat product (sheet steel) available in all shades, including steels to high elastic limit which is especially important for the frames.

Finally, the invention makes it possible to optimize the management of the production of the arrow elements: by allowing this production from the supply of a single type of material, in the form of a flat product; by bringing a significant decrease in the number of parts needed, since only one triangulation module realizes the equivalent of two or more diagonals traditional, each segment of a corresponding module at a diagonal; and by limiting the operations of transformation into three types of operations: cutting, folding and welding, which can be automated.

Figure 1 est une vue d'ensemble en plan par dessus d'un élément de flèche conforme à la présente invention ;

Figure 2 est une vue en plan par dessous de cet élément de flèche ;

Figure 3 est une vue de côté de l'élément de flèche des figures 1 et 2 ;

Figure 4 est une vue en coupe transversale de l'élément de flèche, suivant IV-IV de figure 3 .

Figure 5 est une vue en coupe transversale de l'élément de flèche, suivant V-V de figure 3 ;

Figure 6 est une vue de face d'un module de triangulation de cet élément de flèche, représenté avant pliage ;

Figure 7 est une vue en perspective du module de triangulation de figure 6, dans son état définitif ;

Figure 8 est une vue en perspective d'une variante du module de triangulation ;

Figure 9 est une vue en perspective d'une autre variante de ce module de triangulation.

The invention will be better understood from the description which follows, with reference to the attached schematic drawing showing, by way of example, an embodiment of this boom element for tower crane, as well as some variants:

Figure 1 is an overall plan view over an arrow member according to the present invention;

Figure 2 is a plan view from below of this arrow element;

Figure 3 is a side view of the boom member of Figures 1 and 2;

Figure 4 is a cross-sectional view of the boom element, according to IV-IV of Figure 3.

Figure 5 is a cross-sectional view of the boom member, according to VV of Figure 3;

Figure 6 is a front view of a triangulation module of the boom element, shown before folding;

Figure 7 is a perspective view of the triangulation module of Figure 6, in its final state;

Figure 8 is a perspective view of a variant of the triangulation module;

Figure 9 is a perspective view of another variant of this triangulation module.

Figures 1 to 5 show an arrow element for tower cranes, of triangular section. The element of arrow includes an upper chord 1, and two lower chords 2 and 3, parallel to each other, which define, two by two, two inclined lateral faces, symmetrical with respect to the longitudinal median plane 4 of the boom element, and a lower face, in particular horizontal.

The upper chord 1 is made of sheet metal cut and folded, in particular steel of elastic limit greater than 360 N / mm ² . The upper chord 1 has an inverted "V" section, this section being continuously variable along the length of the chord and, more particularly, decreasing from one of its ends to the other end (see FIG. and compare also Figures 4 and 5).

The two lower chords 2 and 3, forming a tread for a trolley, are also made of cut sheet metal and folded, in particular steel of elastic limit greater than 360 N / mm ² . Each lower chord 2 or 3 has a rectangular section, continuously variable along the length of this chord and, more particularly, decreasing in height from one end to the other end (see FIG. 3, and compare also FIGS. ).

At the ends of the three members 1, 2 and 3 are provided connection ends, for the assembly of the arrow element considered with other elements of similar arrow. The upper chord 1 thus carries, at one end, a connecting end 5 forming a clevis and, the other end, a connecting end 6 forming tenon. Likewise, the lower chords 2 and 3 each carry, at their respective ends, connection ends 7 and 8.

The two lateral faces and the lower face of the boom element are each constituted by a series of triangulation modules 9. In the example considered, each triangulation module 9 comprises two rectilinear segments 10 and 11 connected to each other in 12 at an angle, so that the module of triangulation 9 has a configuration in "V".

Each triangulation module 9 is made of cut and folded sheet, figure 6 showing the shape of the sheet cut before folding, while Figure 7 shows the definitive configuration of the module of triangulation 9, as obtained after folding of the sheet.

The folding of the sheet is made on the first segment 10, along a longitudinal fold line 13 and, on the second segment 11, following a fold line longitudinal 14. After folding, the two segments 10 is 11 and have a conformation angle.

At the free ends of the two segments 10 and 11, as well as in the corner zone 12, the sheet has special cut-outs 15, 16, 17 and 18, angled entering, which define side clearances.

As shown in Figures 6 and 7, more especially for the second segment 11 near his free end, the segments of the triangulation module 9 may have a variable section (with narrowing or enlargement) along their length.

Considering more particularly the faces side of the boom element (see Figure 3), the assembly of triangulation modules 9 is such that the area 12 of each module 9 is connected to the frame superior 1, while the free ends of both segments 10 and 11 of each module 9 are connected to a lower chord, such as chord 2. Some number of triangulation modules 9 are thus successively mounted, along the length of the arrow, the end of the second segment 11 of a module 9 being close to the end of the first segment 10 of next module 9.

Fixing each triangulation module 9 on the frames 1, 2, 3 is made by welding. In particular, the corner area 12 of each module 9 has a width adapted to the welded connection with one of the two wings of the upper chord 1. The side clearances 15, 16, 17 and 18, located at the level connections of each triangulation module 9 with the frames 1, 2, 3, allow easy access for the welding torch.

According to the same principle, for the constitution of underside of the boom element, other modules of triangulation 9 are mounted and welded between the two lower chords 2 and 3 (see Figure 2).

In the example described so far, referring to the FIGS. 1 to 7, each triangulation module 9 possesses two segments 10 and 11 of unequal lengths. Reports lengths of the two segments 10 and 11 can be modified, and in a variant not shown, these two segments 10 and 11 are of equal lengths, the module of triangulation thus being made symmetrical.

Figures 8 and 9 illustrate other variants.

FIG. 8 shows a triangulation module 9 ' in the general form of "M", which has two segments rectilinear lines 10 and 11 interconnected in an area 12, and a third rectilinear segment 19, located between the two previous segments 10 and 11 and connected, also, at the corner area 12, here relatively elongate. The third segment 19 is not folded longitudinally, and thus retains a configuration flat.

Figure 9 shows a 9 "triangulation module in the general form of "Z", which comprises a first segment rectilinear 20 folded longitudinally, a second segment rectilinear 21 connected to the first in a first zone 22 and a third rectilinear segment 23 connected to the previous one in a second corner zone 24.

The triangulation modules 9 'and 9 ", according to these variants, are still made from sheet metal cut and folded.

• par des modifications de formes des modules de triangulation, telles que modification de l'angle de modules en "V", ou constitution de modules en "W", ou encore combinaison des formes précédemment décrites ;
• par une utilisation des mêmes modules de triangulation associée à des membrures classiques (et non pas constituées en tôle découpée et pliée) ;
• par une application de l'invention à des flèches de grue de section non triangulaire, mais rectangulaire ou trapézoïdale, auquel cas les modules de triangulation sont disposés sur les quatre faces de chaque élément de flèche, à savoir les deux faces latérales, la face supérieure et la face inférieure.

One would not move away from the scope of the invention:

• by shape modifications of the triangulation modules, such as modification of the "V" module angle, or constitution of "W" modules, or a combination of the previously described forms;
• by using the same triangulation modules associated with conventional members (and not made of sheet metal cut and folded);
• by an application of the invention to crane arrows of non-triangular section, but rectangular or trapezoidal, in which case the triangulation modules are arranged on the four faces of each boom element, namely the two lateral faces, the upper face and the underside.

Claims (9)

1. A trelliswork jib element for a tower crane, comprising limbs (1, 2, 3) which in pairs define plane faces, and parts which between them connect the limbs in each of said faces in order to form a series of triangles, said parts being formed by triangulation modules (9, 9', 9") which are each produced from cut sheet metal which is optionally folded, characterised in that each triangulation module comprises at least two rectilinear segments (10, 11; 10, 11, 19; 20, 21, 23) which are joined to each other forming at least one angle (12; 22, 24) and which have at least two free ends, said triangulation module (9, 9', 9") being joined to the limbs (1, 2, 3), particularly by welding, at the free ends of the segments (10, 11; 10, 11, 19; 20, 23) as well as at the angle zone or zones (12; 22, 24) thereof.
2. A jib element for a tower crane according to claim 1, characterised in that at least some of the segments (10, 11; 10, 11, 19; 20, 21, 23) of the triangulation modules (9, 9', 9") have a variable cross-section over the length of the segment concerned.
3. A jib element for a tower crane according to claim 1 or 2, characterised in that each triangulation module (9, 9', 9") is produced from cut sheet metal which is folded (at 13, 14) in the longitudinal direction of the segments (10, 11) of said module, or of some of said segments (20, 23), so as to form angle-shaped segments.
4. A jib element for a tower crane according to any one of claims 1 to 3, characterised in that, at the free ends of its segments (10, 11) and in its angle zone or zones (12; 22, 24), each triangulation module (9, 9', 9") comprises a cut-out (15, 16, 17, 18) which creates a lateral gap facilitating access for the welding of said triangulation module (9, 9', 9") to the limbs (1, 2, 3).
5. A jib element for a tower crane according to any one of claims 1 to 4, characterised in that each triangulation module (9) has a V-shaped configuration which results from two segments (10, 11) which are joined in a single angle zone (12).
6. A jib element for a tower crane according to any one of claims 1 to 4, characterised in that each triangulation module (9') has an M-shaped configuration which results from three segments (10, 11, 19) which are joined in a common angle zone (12).
7. A jib element for a tower crane according to any one of claims 1 to 4, characterised in that each triangulation module (9") has a Z-shaped configuration which results from three segments (20, 21, 23) which are joined successively in two angle zones (22, 24).
8. A jib element for a tower crane according to any one of claims 1 to 7, characterised in that the limbs (1, 2, 3) thereof are produced from cut, folded sheet metal, like the triangulation modules (9, 9', 9").
9. A jib element for a tower crane according to claim 8, characterised in that the limbs (1, 2, 3) made of cut, folded sheet metal have a variable cross-section over the length of the jib element, and more particularly have a cross-section which decreases from one end (5, 7) to the other end (6, 8) of the limb (1, 2, 3).

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