EP0536061A1 - Automatically foldable tower crane - Google Patents

Abstract

This crane can be automatically folded, particularly with a view to transporting it on the road. It comprises a tower (6) which can be folded into two parts (7, 8), a jib (10) which is articulated at the top of the tower (6) and supported by a jib tie (20), connected to the top of a rigid upright (24) which is itself articulated on the rear part of the jib (10), and a rear retaining device (26) connecting the top (23) of the upright (24) to the rear part of a rotating frame (3) which carries a cantledge (4). The jib tie (20) is formed by several rigid elements (28, 29, 30, 31) which are articulated to each other. The rear retaining device (26) is formed by a rigid lower element (36), extended at its upper part by a cable (37) and connected by a connecting rod (39) to the lower part (7) of the tower (6). A motorised member (46) connects together the two parts (7, 8) of the tower (6). <IMAGE>

Description

The present invention relates to an automatically foldable tower crane, in particular for transport on the road, to its place of use and from one site to another. This invention relates more particularly to the overall design of the crane, which makes it possible to avoid any manual intervention during the folding of the machine.

In the field of foldable tower cranes, there are telescopic mast cranes, foldable mast cranes and mast cranes made of a single element. The invention relates to tower cranes of the foldable mast type, that is to say a mast consisting of at least two elements connected to one another by a joint and which can thus be folded one on the other for the transport of the crane, cranes for which it is difficult to automatically eliminate the "slack" of cable appearing during the folding in transport position.

Cranes of this type generally have a jib articulated at the top of the mast and supported by a cable tie connected to the top of a rigid punch, also articulated at the top of the mast and held in position by a cable forming a rear retaining device connecting the top of the punch at the rear part of a rotating chassis which is located at the base of the mast and which carries a ballast of balancing - see for example French patent No. 2,548,646. When the mast folds, the arrow and the punch rotate around their articulation on the mast under the action of the weight of the arrow, the cables constituting the tie rod and the rear retaining device remaining taut during this phase. In the next phase of folding, the boom comes into contact with the upper part of the mast, and gradually the cables of the tie rod and the rear retaining device relax and take "slack" which should be eliminated or compensated if we want to prevent the cables from deteriorating quickly, for example by forming loops.

According to a first known type of embodiment, the cables are manually removed from their end fixings, then are stored by winding on a reel or are coiled on the ground for transport with the lifting machine. This realization requires several manual interventions which significantly increase the duration of the shifting and change of position of the crane, operations which with the industrialization of construction sites, are more and more frequent for this type of machine.

According to a second type of embodiment which is becoming more and more widespread, the cables are motorized, either directly or by means of hauling, and the excess cable length, appearing when the cranes are folded up, are automatically wound on a drum. - see French patent No. 2,636,616 and its first certificate of addition No. 2,643,625. From the point of view of the problem to be solved, this embodiment is entirely satisfactory, but the design is complex and expensive.

The present invention overcomes the drawbacks set out above, by providing an automatically foldable tower crane, that is to say with the elimination of any manual intervention, and the design of which remains simple and economical.

To this end, an automatically foldable tower crane according to the invention comprises, in a known manner, a mast foldable in two parts, one lower and the other upper, interconnected by articulation around a horizontal axis, an articulated boom at the top of the mast and supported by an arrow rod connected to the top of a rigid punch itself articulated at the top of the mast or on the rear part of the boom, and a rear retaining device connecting the top of the punch to the part rear of a rotating chassis which is located at the base of the mast and which carries a balancing ballast, the lower part of the mast being articulated around a horizontal axis on the front of the rotating chassis, while a motorized member such that the cylinder controls the folding / unfolding of the mast; this crane is essentially characterized in that the jib tie rod is formed of at least two rigid elements articulated to one another, and in that the rear retaining device is formed of a rigid element at its lower part , connected by articulation to a fixed point on the rear part of the rotating chassis and extended at its upper part to the arrow punch by a cable, a connecting rod connecting the rigid element of the rear retaining device to the lower part of the foldable mast , and the motorized member connecting together the two parts of the mast.

According to a preferred embodiment of the invention, the tie rod is formed of four successive rigid elements, articulated to each other around horizontal axes, elements the length of which is determined so that the punch being folded over the boom, all four rigid elements are also folded down on the boom and said elements are perfectly folded over each other to occupy the minimum space in height. In addition, the design is such that the crane being fully folded, so in the transport position, the connecting rod and the rigid element of the rear retaining device are aligned, while the cable forming the upper part of this rear retaining device is tense.

Advantageously, the rear part of the boom is provided with a first guide roller, while a second guide roller is disposed at the retractable end of a rear lifting punch whose base is rigidly fixed to the rear. from the top and the upper part of the mast, so that, when the crane is folded, the cable of the rear retaining device comes to rest and is guided on the two rollers while remaining permanently taut.

According to a particular embodiment, in the case of an arrow composed of at least two elements elements, including an arrowhead and an arrowhead, the front part of the arrowhead is of reduced height compared to the current height of the arrow, to provide during its folding on the arrowhead a space where come fit, folded over the rigid arrow punch, the folded part of the arrow tie rod and the upper part of the cable for the rear retaining device.

Whatever the construction details, a tower crane is folded automatically, that is to say without manual intervention, especially for its transport on the road, by solving the problem posed by the "slack" of the cables without resort to the complex and expensive solution of motorizing these cables.

• Figure 1 montre, en vue de côté, une grue à tour repliable automatiquement conforme à la présente invention, en position de travail ;
• Figure 2 montre la même grue, vue de côté, en position repliée de transport ;
• Figure 3 est une vue de côté partielle de cette grue, à plus grande échelle, montrant le détail de la flèche avec son tirant et son poinçon en position relevée ;
• Figure 4 est une vue similaire à la figure 3, montrant la flèche en position repliée en illustrant la disposition de son tirant et de son poinçon dans cette position ;
• Figure 5 est une vue de détail en plan pardessus, montrant partiellement le tirant de flèche ;
• Figure 6 représente une section droite du mât repliable.

In any case, the invention will be better understood, and other characteristics will be highlighted, with the aid of the description which follows, with reference to the appended schematic drawing representing, by way of nonlimiting example, a form d of this automatically foldable tower crane:

• Figure 1 shows, in side view, a foldable tower crane automatically according to the present invention, in the working position;
• Figure 2 shows the same crane, side view, in the folded transport position;
• Figure 3 is a partial side view of this crane, on a larger scale, showing the detail of the boom with its tie rod and its punch in the raised position;
• Figure 4 is a view similar to Figure 3, showing the arrow in the folded position illustrating the arrangement of its tie rod and its punch in this position;
• Figure 5 is a detail view in overcoat plan, partially showing the arrow;
• Figure 6 shows a cross section of the folding mast.

The tower crane shown schematically in Figure 1 comprises in known manner a fixed or rolling base chassis 1 supporting, by means of an orientation device 2, a rotating chassis 3 which carries a counterweight 4 at the rear and at the front of which is articulated, around a horizontal axis 5, a foldable mast 6 composed of a base mast 7 and an upper mast 8 connected to each other by articulation on their rear face around a horizontal axis 9. This crane is provided with a distributing jib 10, unfoldable and foldable, produced here in three successive elements, designated respectively as jib foot 11, intermediate jib folding element 12 and jib tip 13 , articulated together around horizontal axes 14,15, arranged at their lower members (the concept of "lower" member being defined by reference to the arrow in the unfolded working position).

The upper mast 8 is connected to the rotating frame 3 by means of two straightening stays 16 arranged symmetrically on either side of the mast 6 and articulated respectively around a horizontal axis 17 located at the base of the upper mast 8 and around a horizontal axis 18 disposed at the rear part of the rotating chassis 3.

The jib 10 is articulated at the top of the mast 6 about a horizontal axis 19 and is held in position by a jib tie 20 connecting a fixed point 21 of the upper chord 22 of the jib foot 11 to the top 23 of a punch rigid jib 24 inclined towards the rear of the crane and articulated at the base of the jib foot 11 about a horizontal axis 25, said punch 24 being itself held in position by a rear retaining device 26 connecting the top 23 of the arrow punch 24 at a fixed point 27 disposed at the rear part of the rotating chassis 3. The crane is motorized for its mounting, that is to say for raising the mast 6, lifting and unfolding the arrow 10, a hydraulic cylinder 46 connecting for this purpose the base mast 7 to the upper mast 8.

• L'élément supérieur 28 est une double bielle formant un tenon entre son articulation au sommet 23 du poinçon de flèche 24 et son articulation autour d'un axe horizontal 32 sur l'élément suivant 29 ; l'élément suivant 29 est constitué de deux fers plats identiques percés à leurs extrémités et reliés entre eux par des entretoises, l'ensemble des deux fers plats formant une chape pour son articulation en 32 sur l'élément précédent 28 et pour son articulation autour d'un axe horizontal 33 sur l'élément suivant 30 ; l'élément 30 est une double bielle formant un tenon pour son articulation en 33 sur l'élément précédent 29 et formant unechape pour son articulation autour d'un axe horizontal 34 sur l'élément suivant 31 ; enfin, ce dernier élément 31 constituant la plus grande partie du tirant de flèche 20 est constitué d'un profilé en U ouvert en direction de la flèche 10, profilé dont la première extrémité est constituée de deux fers plats soudés symétriquement de part et d'autre du profil et percés de deux alésages 34,35 décalés longitudinalement. le premier alésage 34 assurent la liaison avec l'élément précédent 30, et le deuxième alésage 35 assurant la liaison directement avec l'élément 29 lorsque le tirant de flèche 20 est raccourci en supprimant la double bielle 30 pour obtenir une grue à flèche relevée (voir le tracé en traits mixtes de la figure 5). La longueur du dernier élément 31 du tirant de flèche 20 est du même ordre que celle de la membrure supérieure 22 du pied de flèche 11 située sous ledit tirant 20. La longueur de l'ensemble assemblé et aligné des trois premiers éléments 28,29,30 du tirant de flèche 20 est, quant à elle, du même ordre que la longueur du poinçon de flèche 24.

As shown in detail in FIGS. 3,4 and 5, the tie rod 20 is formed of four successive rigid elements 28,29,30,31:

• The upper element 28 is a double connecting rod forming a tenon between its articulation at the top 23 of the arrow punch 24 and its articulation around a horizontal axis 32 on the following element 29; the following element 29 consists of two identical flat bars pierced at their ends and connected together by spacers, the assembly of the two flat bars forming a yoke for its articulation at 32 on the preceding element 28 and for its articulation around a horizontal axis 33 on the next element 30; the element 30 is a double connecting rod forming a tenon for its articulation at 33 on the preceding element 29 and forming a cap for its articulation around a horizontal axis 34 on the following element 31; finally, this last element 31 constituting the largest part of the tie rod 20 consists of a U-shaped profile open in the direction of arrow 10, the profile of which the first end consists of two flat irons symmetrically welded on either side other of the profile and pierced with two bores 34, 35 offset longitudinally. the first bore 34 ensures the connection with the preceding element 30, and the second bore 35 ensuring the connection directly with the element 29 when the jib tie 20 is shortened by removing the double connecting rod 30 to obtain a jib crane raised ( see the dashed line in Figure 5). The length of the last element 31 of the jib tie rod 20 is of the same order as that of the upper chord 22 of the jib foot 11 located under said tie rod 20. The length of the assembled and aligned assembly of the first three elements 28, 29, 30 of the arrow rod 20 is, in turn, of the same order as the length of the arrow punch 24.

The rear retaining device 26 consists on the one hand of a rigid lower element 36 of profiled U open towards the outside of the crane and connected by articulation to the fixed point 27 disposed at the rear part of the rotating chassis 3, and on the other hand a flexible cable 37 of constant length connecting the top 23 of the arrow punch 24 at the free end 38 of the rigid element 36. A double rigid connecting rod 39 also connects by articulation around horizontal axes the end 38 of the rigid element 36 of the rear retaining device 26 at two fixed points 40 located on either side of the upper part of the base mast 7, a short distance from the articulation 9 of the latter to the upper mast 8.

The crane is also equipped with a first cable guiding device 41 arranged at the rear part of the jib 10 and a second cable guiding device 42 disposed at the retractable end 43 of a rear lifting punch 44 the base 45 of which is rigidly fixed to the rear of the top of the upper mast 8. The two cable guide devices 41 and 42 can in particular be produced in the form of guide rollers, with horizontal axes.

Finally, as clearly shown in FIG. 6, the two parts 7 and 8 of the foldable mast 6 are both constituted by boxes of octagonal section, having anterior 48 and posterior faces 49 parallel to the various axes. articulation, such as articulation 27 and axes 32, 33, 34; this configuration is advantageous in that it approximates the ideal circular section, while offering parallel and perpendicular faces with respect to each other, adapted to the various assemblies and joints required.

• En commandant par le vérin 46 le repliage du mât 6, on provoque le pivotement du mât de base 7 vers l'avant autour de son axe d'articulation 5 sur le châssis tournant 3, tandis que le mât supérieur 8 pivote vers l'arrière, autour de son axe d'articulation 9 sur le mât de base 7, sous l'action des haubans de dressage 16 qui le retiennent. Au cours de ce mouvement, le dispositif arrière de retenue 26 reste sous tension sous l'action du poids de la flèche 10 qui pivote autour de son axe d'articulation 19 par rapport au mât supérieur 8, tandis que simultanément le tirant de flèche 20 reste également sous tension et que le poinçon de flèche 24 pivote autour de son axe d'articulation 25 par rapport au mât supérieur 8. Le mouvement se poursuivant, le câble arrière de retenue 37 vient s'appuyer progressivement sur le dispositif de guidage 42 du poinçon arrière de relevage 44 de telle façon que le câble 37 soit guidé et que les efforts restent admissibles. Lorsque la flèche 10 se trouve rabattue contre le mât supérieur 8, le tirant 20 se replie sur lui-même sous l'action de son propre poids tandis que le poinçon de flèche 24 se rabat sur la flèche 10 en maintenant toujours en tension le dispositif arrière de retenue 26. En fin d'opération, la grue se trouve dans la position repliée de transport montrée à la figure 2.

From the working position shown in Figure 1, the folding of the crane previously described is carried out as follows:

• By controlling the folding of the mast 6 by the jack 46, the base mast 7 is pivoted forwards around its articulation axis 5 on the rotating frame 3, while the upper mast 8 pivots backwards. , around its axis of articulation 9 on the base mast 7, under the action of the dressing stays 16 which hold it. During this movement, the rear retaining device 26 remains under tension under the action of the weight of the boom 10 which pivots about its axis of articulation 19 relative to the upper mast 8, while simultaneously drawing the boom 20 also remains under tension and the arrow punch 24 pivots about its articulation axis 25 relative to the upper mast 8. The movement continuing, the rear retaining cable 37 comes to bear progressively on the guide device 42 of the rear lifting punch 44 so that the cable 37 is guided and the forces remain admissible. When the boom 10 is folded back against the upper mast 8, the tie rod 20 folds back on itself under the action of its own weight while the arrow punch 24 folds back on the boom 10 while still keeping the device in tension rear retaining 26. At the end of the operation, the crane is in the folded transport position shown in FIG. 2.

According to an advantageous arrangement, the element 31 with a U-shaped profile of the jib tie 20 comes, in the folded transport position, to cover the upper chord 22 of square section of the jib foot 11, thus reducing the height of the assembly formed by the arrow 10 and the tie rod 20 folded. According to another advantageous arrangement, the element 36 of U-profile of the rear tie rod 26 serves for guiding the part of the cable 37 passing between the base mast 7 and the upper mast 8 when the crane is folded. According to yet another characteristic, the retractable end 43 of the rear lifting punch 44 can, when the crane is folded, be itself partially folded to limit the overall dimensions of the crane during its transport.

It goes without saying that during the unfolding of the crane, from its folded transport position, the movements are opposite to those previously described, the jack 46 being controlled in the opposite direction.

In the example described here, where the jib 10 is composed of several elements 11, 12, 13 articulated to each other at their lower members, a device 47 allows the folding of this jib 10 independently of the general folding of the crane previously described. According to an advantageous arrangement, in the case where the arrowhead 13 is folded over the entire length of the arrowhead 11, the front part of the arrowhead 13 is of reduced height compared to the current height of the arrow 10, in order to provide in the folded position a space in which are housed, plumb with the folded rigid punch 24, the folded part of the jib tie rod 20 and the upper part of the rear retaining cable 37.

Finally, the crane being folded, it is easy to remove the double connecting rod 30 and to pin the axis 33 of the element 29 of the jib tie rod 20 directly on the axis 35 of the element 31 to form a tie rod arrow 20 shorter, in which the axis 34 is also eliminated. An unfolded boom crane is thus obtained in the unfolded state.

• - par l'utilisation d'un tirant de flèche réalisé en un nombre quelconque d'éléments rigides articulés entre eux, ces éléments étant au nombre de deux au moins ;
• - par l'utilisation d'un dispositif arrière de retenue différent de celui décrit par ses détails constructifs ;
• - en remplaçant le vérin 46 par tout organe motorisé équivalent ;
• - par l'utilisation d'un mât en caisson ou en treillis de section différente de la forme octogonale;
• - par une adaptation du même principe de repliage à des grues de conception différente, en ce qui concerne la structure de la flèche et son dispositif de repliage.

As is obvious, and as follows from the above, the invention is not limited to the sole embodiment of this automatically foldable tower crane which has been described above, by way of example; on the contrary, it embraces all the variants of implementation and application based on the same principle. Thus, one would not depart from the scope of the invention:

• - By the use of a tie rod made of any number of rigid elements hinged together, these elements being at least two in number;
• - by the use of a rear retaining device different from that described by its construction details;
• - by replacing the actuator 46 by any mo equivalent torized;
• - by the use of a box or truss mast with a section different from the octagonal shape;
• - By adapting the same folding principle to cranes of different design, as regards the structure of the boom and its folding device.

Claims (11)

1. Self-folding tower crane, in particular for transport on the road, of the type comprising a foldable mast (6) in two parts, one lower (7) and the other upper (8), interconnected by articulation around a horizontal axis (9), an arrow (10) articulated at the top of the mast (6) and supported by a tie rod (20) connected to the top of a rigid punch (24) itself articulated to the top of the mast (6) or on the rear part of the boom (10), and a rear retaining device (26) connecting the top (23) of the punch (24) to the rear part of a rotating frame (3) which is located at the base of the mast (6) and which carries a balancing ballast (4), the lower part (7) of the mast (6) being articulated around a horizontal axis (5) on the front of the rotating frame (3), while a motorized member (46) such as a cylinder controls the folding / unfolding of the mast (6), characterized in that the jib tie rod (20) is formed from at least two e rigid elements (28, 29, 30, 31) articulated to one another, and in that the rear retaining device (26) is formed by a rigid element (36) at its lower part, connected by articulation at a fixed point (27) of the rear part of the rotating frame (3) and extended at its upper part to the arrow punch (24) by a cable (37), of constant length, a connecting rod (39) connecting the rigid element (36) of the rear retaining device (26) at the lower part (7) of the foldable mast (6), and the motorized member (46) connecting the two parts (7,8) of the mast ( 6). 2. Automatically foldable tower crane according to claim 1, characterized in that the jib tie rod (20) is formed by four successive rigid elements (28, 29, 30, 31) articulated to each other around horizontal axes ( 32.33.33). 3. Automatically foldable tower crane according to claim 2, characterized in that the first three elements (28, 29, 30) of the jib tie rod (20) consist of double connecting rods. 4. Automatically foldable tower crane according to claim 2 or 3, characterized in that the last element (31), constituting the largest part of the jib tie rod (20), consists of a U-shaped profile open in the direction of the arrow (10). 5. An automatically foldable tower crane according to any one of claims 2 to 4, with a jib (10) composed of at least two elements including a jib foot (11) and an jib tip (13), characterized in that the length of the last element (31) of the jib tie (20) is of the same order as that of the upper chord (22) of the jib foot (11) located under said tie rod (20), and in that the length of the assembled and aligned assembly of the first three elements (26,29,30) of the arrow tie (20) is of the same order as the length of the arrow punch (24). 6. Automatically foldable tower crane according to claim 5, characterized in that the front part of the jib tip (13), which folds down over the entire length of the jib foot (11), is of reduced height relative to at the current height of the boom (10), to provide in the folded position a space where are housed, plumb with the rigid punch (24) folded, the folded part of the drawbar (20) and the upper part of the cable (37) of the rear retaining device (26). 7. Automatically foldable tower crane according to any one of claims 2 to 6, characterized in that the jib tie rod (20) is designed to be shortened by deleting one of its elements (30), to obtain a jib crane (10) raised. 8. An automatically foldable tower crane according to any one of claims 1 to 7, characterized in that the rear part of the boom (10) is provided with a first guide roller (41) for the cable (37) of the rear retaining device (26), while a second guide roller (42) for this cable (37) is disposed at the retractable end (43) of a rear lifting punch (44) whose base (45 ) is rigidly fixed to the rear of the top of the upper part (8) of the mast (6). 9. Automatically foldable tower crane according to any one of claims 1 to 8, characterized in that the rigid lower element (36) of the rear retaining device (26), connected by articulation to the fixed point (27) of the chassis rotating (3), has a U-shaped profile open towards the outside of the crane. 10. Automatically foldable tower crane according to any one of claims 1 to 9, charac characterized in that the connecting rod, connecting the rigid element (36) of the rear retaining device (26) to the lower part (7) of the foldable mast (6), is a double connecting rod (39) connected by articulation at two points fixed (40) located on either side of the lower part (7) of the foldable mast (6), a short distance from the joint (9) with the upper part (8) of the mast (6). 11. Automatically foldable tower crane according to any one of claims 1 to 10, characterized in that the two parts (7,8) of the foldable mast (6) are, one and the other, by boxes of octagonal section, having anterior (48) and posterior (49) faces parallel to the axes of articulation (32, 33,34) of the rigid elements (28,29,30,31) of the arrow rod (20) and the hinge pin (27) of the rigid lower element (36) of the rear retaining device (26) to the rear part of the rotating chassis (3).

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