EP1024106B1 - Method and device for mounting of the top of the tower of tower cranes - Google Patents

Description

The present invention relates to a method and a device for assembly of the constituent elements of the rotating part of a tower crane, this invention is particularly interested in the constitution and mounting the masthead of tower cranes.

Large capacity tower cranes used on construction sites construction and public works, are generally "Rotating at the top", that is to say that they have a fixed mast, of height adjustable by means of additional mast elements, and a part rotating upper, orientable about a vertical axis, which includes a distributing arrow and a counterflange constituting counterweight support.

More particularly, the rotating part of such a crane comprises usually a rotating pivot, surmounted by a masthead also called "Arrow-holder", the arrow and the counter-arrow being situated on both sides of the masthead. The arrow is articulated, by its posterior end, to the face front of the boom carrier, and is maintained in substantially horizontally by means of one or more lines of arrowheads, connecting each obliquely the top of the arrow holder at a point of the arrow. Of analogously, the counterfleche is articulated, by its anterior end, to the rear face of the boom carrier, and it is maintained in substantially horizontally by means of one or more lines of counter-bolts, connecting each obliquely the top of the arrow holder to a point of the camber.

European Patent Application EP 0 635 450 A1, in the name of Applicant, describes a method for mounting the dispensing boom and the counterfleche of such a tower crane. According to this process, the elements of arrow are lined up and assembled on the ground with their tie rods, then one raises and align the tie rods, and possibly those of the counter-arrow, using an auxiliary assembly machine such as a mobile crane. Then, using the same machine, the whole of the arrow or the counterfleche is raised with the tie rods, and the arrow or counter-arrow is presented in front of the masthead previously mounted, so that the free ends of the tie lines correctly at the top of the masthead, thus allowing direct stitching of the tie rods at the top of the masthead.

• Dans une première phase, on assemble par brochage la contreflèche à la base de la tête de mât, précédemment montée, on lie l'extrémité du tirant de la contreflèche à une bretelle de montage fixée provisoirement sur la tête de mât, on relève la bretelle jusqu'à l'alignement du tirant par l'intermédiaire d'un câble de montage formant un mouflage entre cette bretelle et le sommet de la tête de mât précédemment montée, et on broche le tirant de la contreflèche au sommet de la tête de mât.
• Dans une deuxième phase, il est procédé de façon analogue pour le ou les tirants de la flèche, c'est-à-dire que l'on assemble par brochage la flèche à la base de la tête de mât, du côté opposé à la contreflèche, on lie l'extrémité libre du ou des tirants de flèche à une bretelle de montage, fixée provisoirement sur la tête de mât, on relève cette bretelle jusqu'à l'alignement du tirant, ou des tirants reliés les uns aux autres, par l'intermédiaire du câble de montage précité formant un autre mouflage entre ladite bretelle et le sommet de la tête de mât précédemment montée, et on broche le ou les tirants de la flèche au sommet de la tête de mât.

Also known from the European patent application EP 0 846 650 A1 in the name of the Applicant, a method for mounting tie rods tower cranes, of the kind in question, according to which:

• In a first phase, the pinch is attached to the base of the mast head, previously assembled, the tie rod end is connected to a mounting strap temporarily fixed to the masthead, the ramp is lifted. until the drawbar is aligned by means of a halyard mounting cable between this ramp and the top of the previously mounted masthead, and the tie rod is pinned to the top of the masthead. .
• In a second phase, the method is similarly carried out for the tie rod or tie rods, that is to say that the arrow at the base of the mast head is assembled by pinning, on the opposite side to the counterfleche, the free end of the tie rod or tie rods is connected to a mounting strap, provisionally fixed on the masthead, the ramp is raised up to the alignment of the tie rod, or tie rods connected to each other, by means of the aforementioned mounting cable forming another haul between said ramp and the top of the mast head previously mounted, and the pin or the tie rods are pinned to the top of the masthead.

This process is also implemented by aligning and assembling before the ground the elements of arrow, and by using an auxiliary machine hoist to present the counterfleche, then the arrow, facing the masthead previously mounted.

This solution is more advantageous than that of the demand for EP 0 636 450 A1, in particular for tower cranes large capacity whose arrows are provided with several tie rods. However, it still retains some disadvantages.

In particular, the method of EP 0 846 650 A1 requires have a special engine, with auxiliary winch and hauling or with lever and halyard, to perform the alignment and stitching of the tie rods of the arrow and counterfleche, hence a certain constructive complication for the device for implementing the method.

The realization of the hauling, necessary for the alignment and the broaching Tie rods and counterflash also require time. This process also immobilizes for a relatively long time the machine lifting aid, which must be used not only for the operations handling, but also during intermediate operations what is the lifting of the tie rods of the counterfleche and the tie rods of the arrow to using the aforementioned hauling. Finally, the process under consideration requires the execution "In the air" of several manual assembly operations by broaching, with a certain risk for the interveners who have to move on crane parts temporarily held by the auxiliary hoist.

Moreover, this kind of process involves a realization in three "Package" of the rotating part of the crane, namely the "arrow" assembly, the "counterflash" assembly, and the "boom carrier with haulage" assembly. This requires a large volume for storage and transport of constituents of the rotating part, and also implies that the auxiliary lifting gear must successively mount the three "packages".

• de réduire le volume nécessaire pour le stockage et le transport des constituants de la partie tournante, en recherchant la possibilité d'imbriquer les éléments ;
• de réduire le nombre de pièces et parties annexes, spécifiques aux opérations de montage de la grue, en particulier par suppression du mouflage et de sa motorisation, dédiés précédemment à ces opérations ;
• de simplifier et limiter les opérations d'assemblage « en l'air » des éléments constitutifs de la partie tournante, et de rendre ces opérations plus sûres pour les intervenants, en réduisant le nombre des manutentions et des opérations d'assemblage « en l'air » notamment en réduisant le nombre de colis principaux ;
• de réduire le temps d'utilisation de l'engin auxiliaire de montage, tel que grue mobile.

The present invention aims to avoid these drawbacks, and is therefore intended to provide a method and a device for mounting the constituent elements of the rotating part of a tower crane, of the kind concerned, which allow both:

• to reduce the volume necessary for the storage and transport of the constituents of the rotating part, by looking for the possibility of nesting the elements;
• to reduce the number of parts and ancillary parts, specific to the assembly operations of the crane, in particular by deleting the hauling and its motorization, previously dedicated to these operations;
• simplify and limit assembly operations "in the air" of the components of the rotating part, and make these operations safer for stakeholders, reducing the number of handling and assembly operations "in the air "in particular by reducing the number of main packages;
• to reduce the time of use of the auxiliary assembly machine, such as mobile crane.

• à assembler au sol un ensemble formé par la contreflèche, son ou ses tirants et une partie arrière du porte-flèche réalisé en deux parties séparables, à savoir une partie avant et la partie arrière, et à assembler aussi au sol un autre ensemble formé par la flèche, son ou ses tirants et la partie avant du porte-flèche ;
• à l'aide d'un engin de manutention ou de levage, à lever l'ensemble prémonté formé par la contreflèche, son ou ses tirants et la partie arrière du porte-flèche, et à assembler par brochage cet ensemble, suivant un axe horizontal, sur le pivot tournant ou sur un élément de mât ou mât-cabine lié à ce pivot tournant ;
• à l'aide de l'engin de manutention ou de levage, à lever l'ensemble prémonté formé par la flèche, son ou ses tirants et la partie avant du porte-flèche, et à assembler par brochage cet ensemble, suivant un axe horizontal, sur le pivot tournant ou le mât-cabine ;
• à lier entre eux par au moins un axe de brochage les sommets respectifs des parties avant et arrière du porte-flèche.

For this purpose, the method according to the invention essentially consists, for a tower crane whose rotating part comprises a masthead or boom holder, a distributing boom articulated by its rear end to the front face of the boom carrier and connected at the top of the boom carrier by one or more tie rods, and a counter-beam articulated by its anterior end to the rear face of the boom carrier and connected to the top of the boom carrier by one or more tie rods:

• to assemble on the ground an assembly formed by the counterfleche, its or its tie rods and a rear part of the boom carrier made in two separable parts, namely a front part and the rear part, and also to assemble on the ground another assembly formed by the boom, its tie rods and the front part of the boom carrier;
• using a handling or lifting machine, to lift the pre-assembled assembly formed by the counterfleche, its tie rod or rods and the rear part of the boom-carrier, and to assemble by stitching this assembly, along a horizontal axis , on the revolving pivot or on a mast element or mast-booth linked to this rotating pivot;
• using the handling or lifting equipment, lifting the pre-assembled assembly formed by the boom, its tie rod or rods and the front part of the boom carrier, and assembling this assembly together by a horizontal axis , on the revolving pivot or the mast-cabin;
• to link together by at least one pin axis the respective vertices of the front and rear portions of the arrow holder.

Thus, the invention is essentially based on the initial separation of the arrow holder in two parts, respectively a front part and a part rear, which allows to premount the ground two separate sets, including the one against the arrow and the rear part of the arrow holder, and the other the arrow and the front part of the arrow holder. These two pre-assembled sets are then successively raised and assembled at the turning pivot or at the top of the mast-cabin by broaching. The two component parts of the arrow carrier are also linked together by broaching, in their upper portions, of in order to finally constitute a complete and rigid triangular or polygonal (seen from the side).

Advantageously, the assembly on the ground of the assembly formed by the arrow, its tie rods and the front part of the arrow holder is made by binding hingedly the base of the front part of the arrow holder at the end posterior of the foot of the arrow, and also binding the front part of the arrow-holder at the foot of an arrow by a means limiting the pivoting, forwards and towards the back of the front part of the arrow holder relative to the arrow. The angular movement thus allowed, for example of the order of 5 °, facilitates the final binding operation of the vertices of the front and rear parts of the boom carrier.

In a particular embodiment, the assembly operation on the ground of the assembly formed by the boom, its tie rods and the front part of the arrow holder also includes, for the or each pulling of the arrow, the attachment from a rear part of the tie rod to the top of the front part of the boom carrier, the fixing a front part of the same tie at an intermediate point of the arrow, bringing the rear and front parts closer together with a sling pulled by an auxiliary handling or lifting equipment, and the pinning of the front end of the rear part of the tie rod on the rear end from the front part of the tie rod. The tie rods are thus stitched together, by ground operations, and they find themselves in an aligned position.

The lifting operation of the assembly formed by the counterfleche, its or its tie rods and the rear part of the bow carrier is feasible, according to a first mode of implementation, using slings including front slings attached to the base of the rear part of the arrow holder, and passing over a deflection member carried by this rear part, and rear slings attached to the structure of the counterfleche, so as to maintain the structure of substantially horizontal counterfleche during the lifting of this together with its stitching on the rotating pivot or the mast-cabin, the tie rods of the counterflash being aligned and stretched.

In another embodiment, constituting a variant of the preceding, the lifting operation of the assembly formed by the counterfleche, its or its tie rods and the rear part of the bow carrier is made using slings including front slings attached to the base of the rear section of the arrow holder, but not under any deflection, and rear slings attached to the structure of the counterfleche, the slings being of length adapted to maintain the structure of the counterfleche in an inclined position by horizontally, during the lifting of this assembly and its broaching on the revolving pivot or the mast-cabin, the rear part of the boom carrier being pivoted backwards and in abutment so that the tie rods remain relaxed; the structure of the counterfleche is brought back to the horizontal, and the the tie rods are put in tension, after broaching said assembly on the pivot rotating or the mast-cabin.

Since the assembly is first assembled including the counterfleche and the rear part of the boom holder, then the assembly of the assembly comprising the boom and the front part of the boom carrier, the still advantageously comprises, after the broaching operation of the first of these sets on the swivel or the mast-cabin, the realization of a provisional connection with play now the rear part of the arrow holder in erected position, pending the pinning of the top of the front part of the arrow holder on the top of said rear portion. This temporary liaison with play, not involved in the work of the crane, is achievable by means of retaining rods and lights, connecting the top of the rear part of the boom holder with rotating pivot or mast-cabin.

The lifting operation of the assembly formed by the boom, its or tie rods and the front part of the boom carrier, is also carried out using slings preferably by keeping the arrow substantially horizontal to its pinning on the rotating pivot or the mast-cabin, then by rotating the arrow slightly upwards around the axis performing this broaching, to achieve a approach pinning with game between the top of the front part and the top the rear part of the boom holder. Then, it is pivoted reverse of the arrow leading to the rear part of the arrow holder, and to the realization of a definitive broaching. More particularly, the pivoting reverse of the arrow, driving forward thanks to its dead weight more important the rear part of the arrow holder, makes move the pinhole the end of said rear portion following an arc of a circle, the center corresponds to the pinning axis of the counter-arrow and the rear part the boom holder on the rotating pivot or the mast-cabin. At the same time, the final broaching hole from the top of the front part of the arrow holder is moves along another arc of a circle whose center corresponds to the axis of pinning of the boom and the front part of the boom holder on the rotating pivot or the mast-cabin. Through these movements, the final pinning holes respective vertices of the two parts of the arrow holder are sure to find a common axis, at the point of intersection of the two mentioned arcs of circle, whatever the starting geometrical position of these pin holes, and thus the realization of the definitive broaching is always possible. As we includes, this final broaching ensures the stiffening of the arrow holder, necessary to ensure that it performs its function during the work of the crane.

• une partie avant de porte-flèche, comportant des montants liés rigidement entre eux et pourvus à leurs extrémités inférieures de tenons ou chapes, coopérant avec des chapes ou tenons prévus à l'extrémité postérieure du pied de flèche, ainsi qu'avec des chapes ou tenons prévus sur le pivot tournant ou le mât-cabine,
• une partie arrière de porte-flèche, séparable de la partie avant et comportant des montants liés rigidement entre eux et pourvus à leurs extrémités inférieures de tenons ou chapes, coopérant avec des chapes ou tenons prévus à l'extrémité antérieure de la structure de la contreflèche, ainsi qu'avec des chapes ou tenons prévus sur le pivot tournant ou le mât-cabine,
• les parties avant et arrière du porte-flèche étant encore pourvues, à leurs sommets respectifs, d'organes complémentaires tels que tenon et chape, pour la liaison par brochage entre ces deux parties.

For the implementation of the previously defined editing method, the invention also relates to a device which essentially comprises, in combination:

• a front part of the boom carrier, comprising uprights rigidly connected to each other and provided at their lower ends with pins or clevises, cooperating with clevises or pins provided at the rear end of the boom foot, as well as with clevises or pins provided on the swivel pivot or mast-cabin,
• a rear part of the boom carrier, separable from the front part and having uprights rigidly connected to each other and provided at their lower ends with pins or clevises, cooperating with clevises or tenons provided at the front end of the counterflight structure; , as well as with clevises or tenons provided on the rotating pivot or the mast-cabin,
• the front and rear portions of the boom carrier being further provided, at their respective vertices, complementary members such as tenon and clevis for the connection by broaching between these two parts.

According to one embodiment of this device, the front part of the arrow holder is connected, via a crutch consisting of two sections unequal joints between them, in the posterior part of the foot of arrow, one of the sections of the crutch including a support member on the foot of the mast, in order to limit the forward and backward pivoting of the front of the arrow holder relative to the arrow.

According to another advantageous arrangement, the tenon and the clevis complementary, provided at the vertices of the front and rear parts of the boom carrier, have corresponding front and back holes, respectively for carrying out approach pinning with clearance, and for final broaching, between the post and the screed.

• Il n'est plus nécessaire de prévoir une motorisation (avec son alimentation en énergie) et un mouflage, pour effectuer l'alignement et le brochage des tirants de la flèche et éventuellement de la contreflèche, d'où simplification et économie.
• Par la suppression de la réalisation d'un mouflage pour l'alignement et le brochage des tirants de flèche, l'invention procure aussi un gain de temps dans les opérations de prémontage et de montage.
• La plupart des opérations de prémontage, concernant notamment l'ensemble formé par la flèche, son ou ses tirants et la partie avant du porte-flèche, et l'ensemble formé par la contreflèche, son ou ses tirants et la partie arrière du porte-flèche, sont réalisées au niveau du sol, donc en toute sécurité, à l'aide d'un engin de manutention de faible capacité.
• Seuls deux « colis », à savoir d'une part l'ensemble formé par la flèche, son ou ses tirants et la partie avant du porte-flèche, et d'autre part l'ensemble formé par la contreflèche, son ou ses tirants et la partie arrière du porte-flèche, doivent être successivement manutentionnés par un engin de levage de forte capacité (au lieu de trois « colis » dans les solutions antérieures).
• Les opérations de manutention de ces deux ensembles, à l'aide de l'engin de levage de forte capacité, sont effectuées directement l'une à la suite de l'autre, sans qu'il soit nécessaire de réaliser, entre ces opérations, d'autres opérations intermédiaires telles que relevage des tirants de flèche et de contreflèche ; le temps d'immobilisation de l'engin de levage de forte capacité est donc minimisé.
• Toutes les opérations de brochage, qui restent à exécuter « en l'air », s'effectuent à l'aplomb du mât de la grue, donc sans risque pour les intervenants qui, en particulier, n'ont pas à se déplacer en hauteur sur des parties de grue maintenues seulement par l'engin de levage.
• Etant réalisé en deux parties séparables, chacune de forme sensiblement plane, le porte-flèche offre un encombrement minimal, pour le transport et le stockage.
• Cette structure en deux parties du porte-flèche en facilite aussi la fabrication, en évitant tout assemblage mécanosoudé en volume, chaque partie étant un simple treillis plan, avec deux montants réunis par des traverses.
• La liaison entre l'extrémité postérieure de la flèche, la base de la partie avant du porte-flèche et le sommet du mât-cabine s'effectue en un seul point, plus particulièrement suivant le même axe de brochage, permettant ainsi une triangulation simple et évitant, de ce fait, tous les moments (couples) internes de flexion.
• De même, la liaison entre l'extrémité antérieure de la contreflèche, la base de la partie arrière du porte-flèche et le sommet du mât-cabine s'effectue en un seul point, plus particulièrement suivant le même axe de brochage, permettant ainsi une triangulation simple et évitant de ce fait tous les moments (couples) internes de flexion.

In general, the method and the device for mounting the mast head of tower cranes, objects of the invention, have the following advantages, with regard to the prior art:

• It is no longer necessary to provide a motor (with its power supply) and a haul, to perform the alignment and pinning of the tie rods and possibly the counterfleche, resulting in simplification and economy.
• By eliminating the realization of a haul for the alignment and the broaching of the tie rods, the invention also provides a saving of time in the pre-assembly and assembly operations.
• Most of the pre-assembly operations, in particular concerning the assembly formed by the boom, its tie rods and the front part of the boom carrier, and the assembly formed by the counterflash, its tie rod or rods and the rear part of the carrier boom, are made at ground level, so safely, using a low capacity handling equipment.
• Only two "packages", namely on the one hand the assembly formed by the boom, its or its tie rods and the front part of the boom carrier, and on the other hand the assembly formed by the counterfleche, or its tie rods and the rear part of the boom carrier, must be successively handled by a high capacity hoist (instead of three "packages" in the previous solutions).
• The handling operations of these two sets, using the high capacity lifting gear, are carried out directly one after the other, without it being necessary to perform, between these operations, other intermediate operations such as lifting of the tie rods and the counterfleche; the downtime of the high capacity hoist is therefore minimized.
• All broaching operations, which remain to be performed "in the air", are carried out directly above the mast of the crane, thus without risk for the workers who, in particular, do not have to move up on crane parts held only by the hoist.
• Being made of two separable parts, each of substantially planar shape, the boom holder provides a minimal bulk, for transport and storage.
• This two-part structure of the boom carrier also facilitates the manufacture, avoiding any mechanically welded assembly in volume, each part being a simple planar mesh, with two uprights joined by crosspieces.
• The connection between the rear end of the boom, the base of the front part of the boom carrier and the top of the mast-cabin is made at a single point, more particularly along the same pinning axis, thus allowing a simple triangulation and thus avoiding all internal bending moments (couples).
• Similarly, the connection between the anterior end of the counterfleche, the base of the rear part of the boom carrier and the top of the mast-cabin is made at a single point, more particularly along the same axis of broaching, thus allowing a simple triangulation and thus avoiding all the internal moments (couples) of flexion.

Figure 1 est une vue d'ensemble de côté, à l'état monté, d'une grue à tour à laquelle s'applique le procédé de la présente invention ;

Figure 2 est une vue en perspective éclatée de la tête de mât et des parties adjacentes, notamment de la flèche et de la contreflèche ;

Figure 3 est une vue de détail , de côté, de la partie arrière du pied de flèche et d'une portion inférieure de la partie avant du porte-flèche ;

Figure 4 est une vue de détail, de côté, de l'extrémité avant de la contreflèche et d'une portion inférieure de la partie arrière du porte-flèche ;

Figure 5 est une vue de détail, de côté, des portions supérieures des parties avant et arrière du porte-flèche, réunies entre elles ;

Figure 6 représente, en vue de côté, l'ensemble formé par la flèche et ses tirants (représentés partiellement) et par la partie avant du porte-flèche, en phase initiale d'assemblage au sol ;

Figures 7 et 8 sont des vues de côté similaires à figure 6, illustrant deux phases ultérieures de l'assemblage au sol dudit ensemble ;

Figure 9 est une vue de côté illustrant dans son principe le montage, sur le mât-cabine, de l'ensemble formé par la contreflèche, ses tirants et la partie arrière du porte-flèche ;

Figure 10 représente plus en détail l'opération de la figure 9, particulièrement sous l'aspect manutention dudit ensemble, dans un premier mode de mise en oeuvre ;

Figure 11 est une vue similaire à figure 10, illustrant un deuxième mode de mise en oeuvre de la manutention dudit ensemble ;

Figures 12, 13 et 14 illustrent les phases successives d'un troisième mode de mise en oeuvre de l'assemblage et de la manutention de cet ensemble ;

Figure 15 est une vue de côté illustrant la première phase du montage, sur le mât-cabine, de l'ensemble formé par la flèche, ses tirants et la partie avant du porte-flèche ;

Figures 16 et 17 sont des vues de côté similaires à la figure15, illustrant deux phases ultérieures du montage dudit ensemble sur le mât-cabine ;

Figure 18 est une vue similaire aux précédentes, montrant la phase finale de montage de la partie tournante de la grue ;

Figure 19 est une vue de côté illustrant une phase de montage, dans une variante de l'invention ;

Figure 20 est une vue en perspective éclatée de la région du sommet du porte-flèche, relative à cette variante ;

Figures 21 et 22 sont des vues de côté similaires à figure 19, illustrant des phases ultérieures du montage pour la même variante.

The invention will in any case be better understood with the aid of the description which follows, with reference to the appended schematic drawing which, by way of example, illustrates embodiments of this method for mounting the head of the mast tower cranes, and represents embodiments of the device for the implementation of this method:

Figure 1 is an overall side view, in the assembled state, of a tower crane to which the method of the present invention applies;

Figure 2 is an exploded perspective view of the masthead and adjacent portions, including the arrow and the counter-arrow;

Figure 3 is a detail view, from the side, of the rear part of the jib foot and a lower portion of the front part of the boom holder;

Figure 4 is a detail view, from the side, of the front end of the counterfleche and a lower portion of the rear portion of the boom holder;

Figure 5 is a detail view, from the side, of the upper portions of the front and rear portions of the arrow holder, joined together;

Figure 6 shows, in side view, the assembly formed by the boom and its tie rods (shown partially) and the front part of the boom holder, in the initial phase of assembly on the ground;

Figures 7 and 8 are side views similar to Figure 6, illustrating two subsequent phases of assembly on the ground of said assembly;

Figure 9 is a side view illustrating in principle the mounting on the mast-cabin, the assembly formed by the counterfleche, its tie rods and the rear portion of the boom holder;

Figure 10 shows in more detail the operation of Figure 9, particularly in the handling aspect of said assembly, in a first embodiment;

Figure 11 is a view similar to Figure 10, illustrating a second embodiment of the handling of said assembly;

Figures 12, 13 and 14 illustrate the successive phases of a third embodiment of the assembly and handling of this assembly;

Figure 15 is a side view illustrating the first phase of assembly, on the mast-cabin, of the assembly formed by the boom, its tie rods and the front part of the boom holder;

Figures 16 and 17 are side views similar to Figure 15, illustrating two subsequent phases of mounting said assembly on the mast-cabin;

Figure 18 is a similar view to the previous, showing the final phase of mounting the rotating part of the crane;

Figure 19 is a side view illustrating a mounting phase, in a variant of the invention;

Figure 20 is an exploded perspective view of the region of the top of the arrow holder, relating to this variant;

Figures 21 and 22 are side views similar to Figure 19, illustrating subsequent phases of the assembly for the same variant.

Some figures have enlarged details, designated by the letters A, B, C, etc ...

The tower crane shown in FIG. 1 comprises, in a known manner, a base frame 1 fixed or rolling, a mast 2 height adjustable topped a fixed pivot 3 and a rotating part 4, orientable about a vertical axis, which itself includes a masthead or "arrow holder" 5, an arrow dispenser 6 along which moves a carriage 7, and a counter-arrow 8 carrying a counterweight 9. In the example under consideration, the arrow holder 5 overcomes a short section of mast 10, called "mast-cabin", also belonging to the part rotating 4 and on which is fixed laterally the driving cabin 11 of the crane.

In a manner also known per se, the arrow 6 is composed of several aligned elements, with lattice structure, including a first element 12 "foot of arrow", articulated by its posterior end at the base of arrow holder 5 and on the mast-cabin 10, about a horizontal axis. Arrow 6 is maintained in a substantially horizontal position by two oblique tie-rods 13 and 14, both connected to the top 15 of the arrow holder 5, and also linked, respectively, at two intermediate points 16 and 17 (spaced from each other) of the arrow 6. The tie rods 13 and 14 are themselves formed, each by several successive elements articulated between them, and can thus be also referred to as "tie lines".

The counterfleche 8 is, relative to the masthead 5, the opposite side at the arrow 6, the anterior end of the counter-arrow 8 being articulated, around a horizontal axis 18, at the base of the boom holder 5 and on the mast-cabin 10. This counterfleche 8 is maintained here in a substantially horizontal position by a double oblique pulling 19, which connects two symmetrical points 20 of the part posterior of the structure of the counterfleche 8 at the top 15 of the arrow holder 5. Like the tie rods 13 and 14, the tie rods 19 are composed of several successive elements, articulated between them. The counterfleche 8 also has a lattice structure (see Figure 2).

The arrow holder 5 consists of two removable and separable parts one of the other, namely a front portion 21 and a rear portion 22, shown separated from each other in FIG. front portions 21 and rear 22 converge at the top 15 of the arrow holder 5.

The front portion 21 of the arrow holder 5 is associated with the arrow 6 and, more particularly, at the foot of arrow 12. This front portion 21 comprises two convergent amounts 23, joined together at their apex, and connected between them, respectively, at their base and at an intermediate height, by two horizontal crosspieces 24 and 25. The lower ends of the two uprights 23 have respective tenons 26, each pierced with a pinhole 27. The closer upper ends of the two uprights 23 are assembled to another post 28, pierced with two holes 29 and 30, the one before and the other posterior.

The posterior end of the jib foot 12 comprises, on each side, a clevis 31 with opening directed downwards, receiving one of the tenons lower 26 of the front part 21 of the arrow holder 5. A boss 32 on each of these tenons 26, and a safety axis 33 (see detail in FIG. the uncoupling between each clevis 31 and the corresponding tenon 26.

Referring again to FIGS. 2 and 3, the front portion 21 of the boom carrier 5 is also connected to the foot of arrow 12 via a crutch 34, consisting of two unequal sections 35 and 36, hinged together around them an intermediate axis 37. The first section 35, of greater length, is articulated by one end to a yoke 38 connected to the cross member 25 of the part before 21 of the arrow holder 5; it has, at its opposite end, a plate support 39 intended to rest on the upper chord 40 of the boom foot 12. The second section 36, of shorter length, is articulated around an axis 41 at the posterior end of the upper chord 40 of the boom foot 12. In Figure 3, the stand 34 is shown in the folded position, position in which it limits the forward pivoting of the front portion 21 of the 5. In the unfolded position, the same stand 34 limits the pivoting towards the rear of the front part 21 of the arrow holder 5. The angle between the two limit positions of this front portion 21 of the arrow holder 5 is of the order of 5 °.

The rear portion 22 of the arrow holder 5 is associated with the counterfleche 8. This rear portion 22 comprises two convergent main uprights 42, gathered at one another at their summit, and connected to each other, respectively to their base and at an intermediate height, by two horizontal crosspieces 43 and 44. The lower ends of the two uprights 42 comprise tenons 45, each pierced with an opening 46. The upper ends the two uprights 42 are assembled to a yoke 47, of which each branch has two holes, one anterior and the other posterior. The rear portion 22 of the boom holder 5 further comprises two retaining rods 48, articulated by their upper ends under the yoke 47. The end lower of each connecting rod 48 carries a clevis 49.

The anterior end of the counterfleche 8 comprises, on each side, a clevis 50 with opening directed downwards, receiving one of the tenons 45 of the rear part 22 of the arrow holder 5. A boss 51 on each of these tenons 45, and a safety pin 52, prohibit the uncoupling between each clevis 50 and the corresponding pin 45 - see Figures 2 and 4.

In a particular embodiment (see Figure 10), the part rear 22 of the boom holder 5 has a strap 53 hinged on the uprights 42, and intended to deport the point of attachment of the slings of handling, as detailed below.

Optionally, the rear portion 22 of the boom carrier 5 comprises at least a connecting bar 81, articulated on the crosspiece 44. This bar is fixed on the front portion 21 of the boom carrier, once the crane is fully assembled, and serves as triangulation bar reinforcing the connection between the front parts 21 and rear 22 of the arrow holder 5.

Referring again to FIG. 2, the cabin mast 10 includes, at its top, two clevises 54 located respectively on both sides of the mast-cabin and facing forward, two other yokes 55 located respectively both sides of the mast-cab and facing rear, and two legs 56 located respectively on both sides of the mast-cabin and facing upwards. The two front clevises 54 of the mast-cabin 10 are provided to receive the lower tenons 26 of the front portion 21 of the arrow holder 5, as well as the posterior clevises 31 of the foot of arrow 12. The two rear clevises 55 of the mast-cabin 10 are provided to receive the lower tenons 45 of the part rear 22 of the boom carrier 5, as well as the previous clevis 50 of the 8. Finally, the two legs 56 of the mast-cabin 10, each pierced of a light, are provided to receive the lower clevises 49 of the connecting rods retainer 48 of the rear portion 22 of the boom holder 5.

It will be noted that in the permanently mounted state, the upper screed 47 of the rear portion 22 of the arrow holder 5 receives the upper pin 28 of the front portion 21 of the same boom holder, the nesting of these two elements being illustrated by Figure 5 which shows the region of the top 15 of the head of mast.

We will now describe the procedure followed for the assembly of the tower crane.

A first phase consists of assembling, on the ground, the elements of the counterfleche 8 and associated parts, using a handling machine low capacity (maximum load for example less than or equal to 4 tons). The elements of the double pulling 19 of the counterfleche 8 are then put in place, as well as the rear portion 22 of the arrow holder 5, so as to constitute a triangular-shaped structure, formed of the counterfleche 8, the double pull 19 and said rear portion 22.

A second phase consists of assembling, on the ground, the elements of arrow 6 and associated parts, still using a handling machine low capacity. The successive elements of the arrow 6 are aligned and assembled together and the carriage 7 is also put in place. The front part 21 arrow carrier is brought, its crutch 34 being folded and resting, by its support plate 39, on the upper chord 40 of the boom foot 12 - see figure 6. The two lines of tie rods 13 and 14 of the arrow 8 are also installed: the rear parts 13a or 14a of these tie rods 13 and 14 are joined by a double rod 82, which hangs on a boss 83 formed around the hole front 29 of the pin 28 located at the top of the front portion 21 of the arrow holder (see Figure 5), the double rod 82 being held in the hooked position by a clamping member. The front portion 13b or 14b of each tie 13 or 14, still separated from the rear part, is linked to point 16 or 17 at the chord upper 40 of the arrow 6. As shown by the enlarged details A and B of FIG. 6, for the longer tie rod 14, the front end of the rear portion 14a has a yoke 57, and the rear end of the part before 14b of this tie rod has a pin 58 preferably with light or vice versa. It is also provided a roller 59 mounted at the front end of the rear portion 14a of the line of tie rods 14, the roller 59 being able to roll on the upper chord 40.

To bring the two parts of each tie 13 or 14 of the arrow 6, a sling 60 is used passing over two movable pulleys 61, and on the hook 62 of the aforementioned handling machine - see detail C of Figure 6.

By means of the sling 60, it is first of all carried out the approximation of the two portions 14a and 14b of the upper tie line 14, larger length, and these parts are stitched together by an axis linking the yoke 57 with tenon 58, whose light allows a game to remain - see Figure 7.

Using the same sling 60, and the same movable pulleys 61, it is then proceeded to bring together the two parts 13a and 13b of the line lower tie rods 13, of smaller length, these two parts being also finally stitched together - see figure 8.

All the operations described so far are performed on the ground.

The next phase consists, using a heavy lifting gear capacity (eg maximum load equal to or greater than 10 tonnes), and the use of slings adapted to perform a handling of the assembly formed by the counterfleche 8, by the double tie 19 and by the rear portion 22 of the arrow holder 5, to lift this assembly and bring it to the mast-cabin 10, as shown generally in Figure 9.

Then, along the horizontal axis 18, a pinning binding the end is carried out front of the counterfleche 8 and the base of the rear portion 22 of the arrow holder 5 with the mast-cabin 10. As shown in detail D of Figure 9, it is also pinning process, by an axis 63, clevises 49 located at the ends lower two retaining rods 48 of the rear portion 22 of the boom carrier 5 on the corresponding legs 56 of the upper part of the mast-cabin 10. This connection having a vertical clearance, thanks to the light 64 formed in each leg 56, the assembly thus set up is finally released backwards by pivoting about the axis 18, using the machine of used, until the abutment of the broaching pin 63 at a stop end of light 64.

This phase is feasible, in a first mode of implementation illustrated in Figure 10, using a set of special slings, consisting of two slings before 65 and two rear slings 66, predefined length, suspended on the same hook 67 of the hoist. The two slings before 65 are attached at a point 68, at the base of the rear portion 22 of the boom holder 5, and they pass on the ramp 53 deployed, so as to be deflected on the end 69 of this ramp 53 which constitutes thus a deported attachment point. The two rear slings 66 are attached at symmetrical points 70, located towards the rear of the structure of the 8. When lifting the assembly, the double tie 19 of the counterfleche 8 is aligned and taut, and the structure of the counterfleche 8 remains in substantially horizontal position which is maintained during the previously described operations of broaching this assembly on the mast-cabin 10.

According to a second mode of implementation, illustrated by FIG. 11, the handling of the whole considered is carried out using another set slings, consisting of two slings before 71 and two rear slings 72, of predefined length. The two slings before 71 are attached to point 68, at the base of the rear portion 22 of the boom carrier 5, and undergo here no deviation between the hook 67 and the attachment point 68. two rear slings 72 are attached to the points 70, located towards the rear of the 8. When lifting the assembly, the two slings before 71 maintain the rear portion 22 of the boom carrier 5 pivoted to the rear relative to the structure of the counterfleche 8, in the stop position against the clevis 50 by the axis 52, so that the elements 73, 74 and 75 of the line of tie rods 19 form a broken line. The structure of the counterfleche 8 is handled by forming, relative to the horizontal, an angle at important, for example equal to or greater than 15 °. This inclination of the counterfleche 8 is preserved during the operations (previously described) of stitching of the assembly on the mast-cabin 10. Once this stitching done, the counterfleche 8 is pivoted about its axis 18 of broaching on the mast-cabin 10, until coming to a substantially horizontal position, the elements 73, 74 and 75 double pull 19 then being aligned and put in tension.

FIGS. 12 to 14 illustrate a third mode of implementation, respecting the assembly and handling of the assembly formed by the counterfleche 8, the tie rods 19 and the rear portion 22 of the arrow holder 1.

FIG. 12 illustrates the stitching operation of the tie rods 19, carried out at ground. For this operation, the rear part 22 of the arrow holder 5 is put into place in its articulation at the front of the structure of the counterfleche 8, and maintained in a substantially vertical position (for example with a slight tilt towards the rear, the angle β being approximately 87 °), with the aid of the low capacity handling. It is then proceeded to the broaching of the each line of tie rods 19.

Then, as shown in Figure 13, it is proceeded, using the same handling machine, tilting forward of the rear portion 22 of the arrow holder 5, to a position inclined towards the front (the angle γ being equal for example at about 9 °). In its tilting, the rear part 22 of arrow holder 5 drives with it the tie rods 19, which are thus put in "pre-tension". This tilting position of the rear portion 22 of the boom carrier 5 is held by a backstop, put in place at the level of the articulation, to maintain the pre-tension of the tie rods 19 - see detail K of Figure 13.

Then, using the high capacity lifting gear, and slings front 71 and rear 72 of current length, whose attachment points respective 68 and 70 are located on the structure of the counterfleche 8, it is lifting the assembly, as shown in Figure 14. The weight distribution then leads to obtaining an angle of inclination α of the order of 6 °, for the counterfleche 8, relative to the horizontal (the rear portion 22 of the boom holder 5 inclining forwardly by an equal angle δ at about 15 °).

Like the previous one, this last mode of implementation renders useless any deflection member for the slings 71 and 72. In addition, the angle of inclination has of the counterfleche, of the order of 6 °, is here more reassuring angle of 15 ° or more reached in the previous mode of implementation artwork. This lower angle avoids introducing horizontal forces on the masthead and on the mast 2, during the disassembly of the counterfleche 8.

Then, the assembly constituted by the arrow 6, by the tie rods 13 and 14 and by the front portion 21 of the boom carrier 5 is handled, using a high capacity lifting gear, this assembly being lifted and brought to the mast-cabin 10, in the extension of the assembly with counterfleche 8 previously mounted. This operation is illustrated by Figure 15, on which the slings used with the hoist are indicated in 76. During the operation, as shown by the detail E of Figure 12, the stand 34 remains folded. The two tie rods 13 and 14 remain relaxed.

It is then a pinning, along a horizontal axis 77, for bind the posterior end of the jib foot 12 and the base of the front part 21 from the boom holder 5 to the cabin mast 10.

With the aid of the hoist, the arrow 6 is then slightly rotated upwards around its axis of broaching 77 with the mast-cabin 10 (position visible in FIG. 15), the front part 21 of the boom carrier 5 then performing a corresponding pivoting backwards. The upper tenon 28 of the part before 21 of the boom holder 5 and engages in the upper yoke 47 of the rear portion 22 of this arrow holder 5. As shown in detail F of the figure 15, it is then proceeded to an approach pinning, with clearance, between the pin 28 and the yoke 47, by means of an axis 78 which passes through the posterior hole 30 of the tenon and the corresponding holes of the yoke 47, the diameter of the hole 30 being greater than that of axis 78.

In the next phase, illustrated in Figure 16, arrow 6 is lowered and brought substantially horizontally, by reverse pivoting around its axis of broaching 77 with the mast-cabin 10, with the aid of the lifting. The rear portion 22 of the boom carrier 5 is driven forward by the previously approached approach pinning, the top of this back part 22 describing a circular arc centered on the axis 18, while the top of the front portion 21 of the arrow holder 5 moves in a circular arc centered on the axis 77, the movement continuing until alignment of the anterior hole 29 of the pin 28 with the corresponding holes of the yoke 47, to the point intersection of the two aforementioned arcs. At the same time, the tie rods 13 and 14 of the arrow 6 line up and stretch, while the crutch 34 unfolds (see detail H of figure 16).

It is then the final binding binding the vertices of the parties front 21 and rear 22 of the boom carrier 5 between them, and the double rod 82 connecting rods 13 and 14, by introducing a pin 79 through the hole front 29 of the pin 28 and corresponding holes of the yoke 47 - see detail G of Figure 16, as well as Figure 5. The arrow holder 5 is then constituted in a rigid structure, of triangular shape, whose three sides are formed respectively by the top of the mast-cabin 10, by the front part 21 (in particularly the uprights 23) and by the rear part 22 (in particular the amounts 42).

A small platform 80 with guardrail, carried by the rear part 22 of the arrow holder 5, allows the workers to safely carry out the broaching operations previously described, linking the respective vertices front 21 and rear 22 parts of the boom holder 5.

It will be noted that after completion by axis 79 of the definitive pinning, linking the vertices of the front portions 21 and rear 22 of the arrow holder 5, the connecting rods of retaining 48 are released from any effort, the broaching axis 63 coming to a point intermediate length of each light 64 - see detail J of the figure 16.

The slings 76 can now be detached from the arrow 6, this one being maintained in a substantially horizontal position by the single rods 13 and 14, stretched between the top 15 of the arrow holder 5 and the points 16 and 17 - see figure 17.

Finally, using the lifting gear now released, it is proceeded to weighting of the counterfleche 8, by bringing and fixing, at the rear of the structure of this counterfleche 8, the blocks constituting the counterweight 9 - see FIG. The crane is then ready to enter service.

Optionally, as illustrated in Figures 15 to 17, one or more constituent blocks of the counterweight 9 can be already set up on the counterfleche 8 in intermediate phases of the assembly of the crane.

Figures 19 to 22 illustrate, as a variant of what has just been described, another version of the broaching of the upper part of the arrow holder 5. This variant implements the following means, clearly visible in FIG. only on the details N and R:

The front portion 21 of the boom holder 5 comprises, at its top, a tenon 28 having a rear hole 30 for the stitching of the line of tie rods 19 of the counterfleche 8, and a hole before 29 for the final broaching of the two parts, respectively before 21 and rear 22, of the boom holder 5.

The rear part 22 of the boom carrier 5 has, at its top, a clevis 47 provided with a hole 84 for the final broaching of the two parts 21 and 22 of the arrow holder 5. The yoke 47 is also provided, externally, with side washers 85 coaxial with the aforementioned hole 84; these washers 85, welded on the yoke 47, have an inner diameter equal to that of the axis of final broaching.

The line of tie rods 19 of the counterfleche 8 has at its end former, two connecting rods 86 and 87. The first rod 86 is a double rod, consisting of two symmetrical plates, which ensures the connection between the end of the line of tie rods 19 and the side washers 85 carried by the upper yoke 47 of the rear portion 22 of the arrow holder 5. The second connecting rod 87, in particular in the form of a clevis, is housed inside the double rod 86, and is connected to the end of the line of tie rods 19, same point as the first rod 86. The center distance of the second rod 87 is slightly lower, for example 2 mm, than that of the double rod 86.

The broaching of the counter-flap 8 is done by connecting the double tie 19 at the upper end of the rear portion 22 of the boom holder 5 by means of the first connecting rod (double connecting rod) 86, the second connecting rod 87 being on standby.

The pinning of the arrow 6 is done by connecting the triangulation of this arrow, at its upper end and more particularly the hole rear 30 of the tenon 28, at the end of the double tie 19 of the counterfleche 8, via the second rod 87.

These broaching operations are performed in the position of the arrow 6 shown in Figure 18 (arrow slightly rotated upward), so analogous to what has already been illustrated in FIG.

In the next phase (Figure 20), the arrow 6 is lowered, and the tie rods 13 and 14 of the arrow 6 are put in tension. Simultaneously; the tie line 19 of the counterfleche 8 is driven forward by the second rod 87, and the rear portion 22 of the boom holder 5, held by the first rod 86, is driven forward by its own weight. The relative movement between rear portion 22 and the front portion 21 of the boom holder 5, which then occurs, corresponds substantially to the difference in distances between the first connecting rod 86 and the second connecting rod 87, and this allows the perfect alignment of the holes of final pinning 29 and 84 of the two parts 21 and 22 of the boom carrier, during the tensioning of the tie rods.

It is then proceeded to definitive pinning, binding the vertices of the parts before 21 and rear 22 of the arrow holder 5 between them, by introduction of an axis 79 through previously aligned holes - see detail R of the FIG. 21. The holding rods 48 are then released from any effort, and that the crutch 34 - compare the details L and M of Figure 19 respectively with the details P and Q of Figure 21.

Finally, the slings 76 can be detached from the arrow 6, maintained by the only tie rods 13 and 14 stretched, this final phase being shown on the figure 22.

This variant has the advantage, in comparison with the version previously described, no longer require a very precise realization centers of the holes at the vertices of the front 21 and rear 22 parts of the arrow holder 5, so to overcome a dimensional constraint.

Disassembly of the rotating part 4 of the crane is feasible, by a series of inverse operations of those previously described, separating first the two parts 21 and 22 of the arrow holder 5, then by handling on the one hand the assembly consisting of the arrow 6, the front portion 21 of the arrow holder 5 and tie rods 13 and 14, and on the other hand the compound consisting of the 8, the rear portion 22 of the arrow holder 5 and the double tie 19. Once separated, the two parts 21 and 22 of the arrow holder 5 offer a minimal space for transport and storage.

• en modifiant l'ordre des opérations de prémontage au sol de l'ensemble avec flèche et de l'ensemble avec contreflèche, voire même en réalisant ces opérations simultanément pour les deux ensembles .
• en appliquant le même procédé, avec les adaptations nécessaires, à des grues avec flèches et/ou contreflèches possédant des tirants en nombre différent de celui considéré dans les exemples précédemment décrits, et illustrés au dessin ;
• en constituant le porte-flèche, toujours par réunion d'une partie avant et d'une partie arrière séparables, mais avec la forme d'un polygone à quatre côtés, tel que rectangle ou trapèze, au lieu d'une forme triangulaire (en vue de côté) ;
• en modifiant la constitution des deux parties du porte-flèche, ou de l'une d'elles, la partie avant ou arrière du porte-flèche étant réalisable sous la forme d'un seul montant, au lieu d'une structure en treillis à deux montants.

One would not depart from the scope of the invention, as defined in the claims:

• by modifying the order of the pre-assembly operations on the ground of the assembly with arrow and the assembly with counterfleche, or even by performing these operations simultaneously for both sets.
• by applying the same method, with the necessary adaptations, to cranes with arrows and / or counterflanges having tie rods in a number different from that considered in the previously described examples, and illustrated in the drawing;
• by constituting the arrow holder, always by meeting a separable front and rear part, but with the shape of a polygon with four sides, such as rectangle or trapezium, instead of a triangular shape (in side view) ;
• by modifying the constitution of the two parts of the boom carrier, or one of them, the front or rear part of the boom carrier being feasible in the form of a single amount, instead of a lattice structure to two amounts.

Claims (24)

1. A method for mounting the revolving part, more particularly the masthead of a tower crane, the revolving part (4) of which comprises a masthead or jib bearer (5), a delivery jib (6) which is articulated by its posterior end to the front face of the jib bearer (5) and connected to the top (15) of the jib bearer (5) by one or more tie rods (13, 14), and a counterjib (8) which is articulated by its anterior end to the rear face of the jib bearer (5) and connected to the top (15) of the jib bearer (5) by one or more tie rods (19), characterized in that it consists:

   in assembling, on the ground, an assembly formed by the counterjib (8), its tie rod or rods (19) and a rear part (22) of the jib bearer (5) which is made in two separable parts (21, 22), namely a front part (21) and the rear part (22), and in also assembling on the ground another assembly formed by the jib (6), its tie rod or rods (13, 14) and the front part (21) of the jib bearer (5) ;

   using a handling or lifting device, in lifting up the pre-built assembly formed by the counterjib (8), its tie rod or rods (19) and the rear part (22) of the jib bearer (5) and in assembling this assembly, by pinning along a horizontal axis (18), on the revolving pivot or on a mast element or mast-cab (10) connected to this revolving pivot;

   using the handling or lifting device, in lifting up the pre-built assembly formed by the jib (6), its tie rod or rods (13, 14) and the front part (21) of the jib bearer (5), and in assembling this assembly, by pinning along a horizontal axis (77), on the revolving pivot or the mast-cab (10) ;

   in using at least one pin (78, 79) to connect the respective tops (28, 47) of the front part (21) and the rear part (22) of the jib bearer (5) together.
2. The method as claimed in claim 1, characterized in that the assembling on the ground of the assembly formed by the jib (6), its tie rod or rods (13, 14) and the front part (21) of the jib bearer (5) is performed by connecting the base (26) of the front part (21) of the jib bearer (5) in an articulated manner to the posterior end (31) of the jib root (12) and by also connecting the front part (21) of the jib bearer (5) to the jib root (12) by a means (34) which restricts the forward and backward pivoting of the front part (21) of the jib bearer (5) with respect to the jib (6).
3. The method as claimed in claim 2, characterized in that the angle between the two limit positions of the front part (21) of the jib bearer (5) is of the order of 5°.
4. The method as claimed in any of claims 1 to 3, characterized in that the operation of assembling on the ground the assembly formed by the jib (6), its tie rod or rods (13, 14) and the front part (21) of the jib bearer (5) comprises, for the or each tie rod (13, 14) of the jib (6), attaching a rear part (13a, 14a) of the tie rod to the top (28) of the front part (21) of the jib bearer (5), attaching a front part (13b, 14b) of that same tie rod to an intermediate point (16, 17) of the jib (6), bringing the rear part (13a, 14a) and the front part (13b, 14b) of the tie rod (13, 14) closer together using a sling (60) pulled by an auxiliary handling or lifting device, and pinning the front end (57) of the rear part (13a, 14a) of the tie rod to the rear end (58) of the front part (13b, 14b) of the tie rod.
5. The method as claimed in any of claims 1 to 4, characterized in that the lifting of the assembly formed by the counterjib (8), its tie rod or rods (19) and the rear part (22) of the jib bearer (5) is performed using slings comprising front slings (65) secured to the base (68) of the rear part (22) of the jib bearer (5) and passing over a deflecting member (53) borne by this rear part (22), and rear slings (66) secured (at 70) to the structure of the counterjib (8) so as the keep the structure of the counterjib (8) raughly horizontal while this assembly is being lifted and pinned to the revolving pivot or the mast-cab (10), the tie rod or rods (19) of the counterjib (8) being aligned and taut.
6. The method as claimed in any of claims 1 to 4, characterized in that the lifting of the assembly formed by the counterjib (8), its tie rod or rods (19) and the rear part (22) of the jib bearer (5) is performed using slings comprising front slings (71) secured to the base (68) of the rear part (22) of the jib bearer (5), but which are not deflected in any way, and rear slings (72) secured (at 70) to the structure of the counterjib (8), the slings (71, 72) being of an appropriate length to keep the structure of the counterjib (8) in an inclined position with respect to the horizontal while this assembly is being lifted and pinned to the revolving pivot or the mast-cab (10), the rear part (22) of the jib bearer (5) being pivoted backward in such a way that the tie rod or rods (19) remain slack, and wherein, after said assembly has been pinned to the revolving pivot or the mast-cab (10) , the structure of the counterjib (8) is returned to the horizontal and the tie rod or rods (19) are tensioned.
7. The method as claimed in claim 6, characterized in that the structure of the counterjib (8) forms, with respect to the horizontal, an angle (α) equal to or greater than 15°, while the assembly concerned is being lifted up and pinned.
8. The method as claimed any of claims 1 to 4, characterized in that, after the tie rod or rods (19) of the counterjib (8) have been pretensioned by tilting the rear part (22) of the jib bearer (5) forward, the assembly formed by the counterjib (8), its tie rod or rods (19) and the rear part (22) of the jib bearer (5) is lifted up using slings comprising front slings (71) and rear slings (72) secured (at 68, 70) to the structure of the counterjib (8) so as to keep the structure and the counterjib (8) roughly horizontal, or at least slightly inclined to the horizontal, while the assembly concerned is being lifted and pinned.
9. The method as claimed in claim 8, characterized in that the structure of the counterjib (8) forms, with respect to the horizontal, an angle (α) of the order of 6° while the assembly concerned is being lifted and pinned.
10. The method as claimed in any of claims 1 to 9, characterized in that it further comprises, after the operation of pinning (at 18) the assembly comprising the counterjib (8) and the rear part (22) of the jib bearer (5) to the mobile pivot or the mast-cab (10), making a temporary connection (48, 49, 56, 63), with play, to hold the rear part (22) of the jib bearer (5) in an upright position while waiting for the top (28) of the front part (21) of the jib bearer (5) to be pinned (at 78, 79) to the top (47) of said rear part (22)
11. The method according to any of claims 1 to 10, characterized in that the lifting of the assembly formed by the jib (6), its tie rod or rods (13, 14) and the front part (21) of the jib bearer (5) is performed using slings (76), keeping the jib (6) rough horizontal until such time as it is pinned to the revolving pivot or the mast-cab (10), then by pivoting the jib (6) upward slightly about the pin (77) used for this pinning so as to approximately pin, with play (at 78), the top (28) of the front part (21) to the top (47) of the rear part (22) of the jib bearer (5).
12. The method as claimed in claim 11, characterized in that, after carrying out the approximate pinning (at 78), the jib (6) is pivoted in the opposite direction, bringing the rear part (22) of the jib bearer (5) forward and performing a definitive pinning operation (at 79) to stiffen the jib bearer (5) , the definitive pinning operation being performed at the point of intersection of an arc of a circle centered on the axis of pinning (18) of the counterjib (8) to the revolving pivot or the mast-cab (10), along which the hole (84) for the definitive pinning of the top (47) of the rear part (22) of the jib bearer (5) travels and another arc of a circle centered on the axis of pinning (77) of the jib (6) to the revolving pivot or the mast-cab (10), along which the hole (29) for the definitive pinning of the top (28) of the front part (21) of the jib bearer (5) travels.
13. A device for implementing the method for mounting the revolving part of a tower crane as claimed in any of claims 1 to 12, characterized in that it comprises, in combination:

    a front part (21) of a jib bearer (5), including uprights (23) joined rigidly together and fitted at their lower ends with tangs (26) or with yokes, collaborating with yokes (31) or with tangs provided at the posterior end of the jib root (12) and with yokes (54) or with tangs provided on the revolving pivot or the mast-cab (10)

    a rear part (22) of a jib bearer (5), separable from the front part (21) and comprising uprights (42) connected rigid together and fitted at their lower ends with tangs (45) or with yokes, collaborating with yokes (50) or with tangs provided at the anterior end of the structure of the counterjib (8) and with yokes or with tangs (55) provided on the revolving pivot or the mast-cab (10),

    the front part (21 ) and the rear part (22) of the jib bearer (5) also being provided, at their respective tops, with complementing members such as tang (28) and yoke (47) so that these two parts (21, 22) can be pinned together.
14. The device as claimed in 13, characterized in that the front part (21) of the jib bearer (5) is connected, by a prop (34) made up of two unequal portions (35, 36) articulated together (at 37), at the posterior part of the jib root (12), one of the portions (35) of the prop (34) including a member (39) for bearing against the mast root (12) so as to limit the forward and backward pivoting of the front part (21) of the jib bearer (5) with respect to the jib (6)
15. The device as characterized in that in claim 13 or 14, characterized in that the or each tie rod (13, 14) of the jib (6) comprises a rear part (13a, 14a) pinned to the top of the front part (21) of the jib bearer (5) and a front part (13b, 14b) separable from the rear part and connected to a point (16, 17) of the jib (6), the front end of the rear part (13a, 14a) comprising a yoke (57) and the rear end of the front part (13b, 14b) comprising a tang (58), preferably with a slot, or vice versa, and means comprising a sling (60) and pulleys (61) being provided for bringing the rear part (13a, 14a) and the front part (13b, 14b) of the tie rod closer together so that they can be pinned together by a pin connecting the yoke (57) to the tang (58)
16. The device as claimed in claim 15, characterized in that in the case of a jib (6) with two lines of tie rods (13, 14), the rear parts (13a, 14a) of the two lines of tie rods are joined together by a double link (82) which fastens onto a boss (83) formed around a hole (29) of the tang (28) situated at the top of the front part (21) of the jib bearer (5).
17. The device as claimed in any of claims 13 to 16, characterized in that the rear part (22) of the jib bearer (5) comprises retaining link rods (48) designed to connect the top (47) of this rear part (22) to the mobile pivot or to the mast-cab (10), the lower end of each link rod (48) preferably bearing a yoke (49) designed to collaborate with lugs (56) of the mast-cab (10), via a pin (63) passing through a slot made in each lug (56).
18. The device as claimed in any of claims 13 to 17 for implementing the method as claimed in claim 5, characterized in that the rear part (22) of the jib bearer (5) includes a strap (53) articulated to its main uprights (42) and designed to offset the point of attachment of the handling slings (65).
19. The device as claimed in any of claims 13 to 18 for implementing the method as claimed in claim 8 or 9, characterized in that said device is fitted with a rear stop which keeps the rear part (22) of the jib bearer (5) in its tilted position to maintain the pretension in the tie rod or rods (19) of the counterjib (8).
20. The device as claimed in any of claims 13 to 19, characterized in that the complementing tang (28) and yoke (47) provided at the tops of the front part (21) and rear part (22) of the jib bearer (5), have corresponding anterior and posterior holes (29, 30) for, respectively, the approximate pinning (pin 78), with play, and the definitive pinning (pin 79) of the tang (28) and the yoke (47)
21. The device as claimed in claim 20, characterized in that the tie rod or rods (19) of the counterjib (8) comprise, at the anterior end, two mounting link rods (86, 87), namely a double link rod (86) providing the connection with lateral washers (85) borne by the yoke (47) provided at the top of the rear part (22) of the jib bearer (5), and another link rod, particularly in the form of a yoke (87), housed inside the double link rod (86) and having a distance between centers slightly shorter than that of the double link rod (86), the other link rod (87) being designed to be connected to a rear hole (30) of the tang (28) provided at the top of the front part (21) of the jib bearer (5), prior to definitive pinning.
22. The device as claimed in any of claims 13 to 21, characterized in that there is also provided, at an intermediate height along the jib bearer (5), at least one bar (81) for connecting the front part (21) and the rear part (22) of the jib bearer (5)
23. The device as claimed in any of claims 13 to 22, characterized in that the base of the rear part (22) of the jib bearer (5) , the anterior end of the counterjib (8) , and the top of the mast-cab (10) are joined together at a single point, along the same pinning axis (18).
24. The device as claimed in any of claims 13 to 23, characterized in that the base of the front part (21) of the jib bearer (5), the posterior end of the jib (6) and the top of the mast-cab (10) are connected together at a single point, along the same pinning axis (17).

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