EP1873114A1 - Transportable tower crane with a mobile ballast device - Google Patents

Abstract

The crane has lateral guys (9), and a mobile ballast device (15) with counterweight formed of lateral blocks (16). The counterweight is connected to a rear part of a rotating platform (2) and a foldable/unfoldable mast (3) by an articulation axle (19) and connecting rods (20), respectively such that the counterweight is straightened and folded in crane usage and transport positions. The counterweight is articulated at the part by lateral plates (18) and connected to a mast`s upper element (5) by the rods, where the plates are extended perpendicular to a counterweight`s longitudinal direction.

Description

The present invention relates, in general, to the field of tower cranes, and more particularly that of transportable tower cranes, which are foldable for use on a construction site, and foldable for transport from a place of use to a other. Even more particularly, this invention relates to such a crane equipped with a mobile ballast device, the term "ballast" here designating a counterweight placed at the base of the crane, for its balancing and stabilization in position d 'use.

By the document EP 0508907 A1 already known is a transportable tower crane, more particularly a foldable and foldable crane, which is equipped at its base with a mobile ballast device.

In a generally known manner, this tower crane comprises a rotating platform, on which is articulated the lower element of the mast, while the upper element of the mast is hinged to the top of the lower element of the mast. The unfolding of the mast is controlled by an articulated assembly with stay cables and connecting rods which, in the particular case of the aforementioned document, comprises a single stay placed in a central position, that is to say located in the vertical median plane of the platform. rotating form and mast.

The mobile ballast, as provided in this document EP 0508907 A1 , is a counterweight mounted on a frame-shaped support, which is itself hinged around a horizontal axis, at the rear of the rotating platform. The front part of this support is hingedly connected, via two lateral rods, to the lower element of the mast.

The counterweight itself, mounted on the support, is made as a single block, with two massive side parts and with a median recessed portion.

In unfolded position of use of the crane, the counterweight and its support rise vertically, above the rear part of the rotating platform.

In the folded transport position of the crane, the counterweight and its support are folded horizontally on the rotating platform, occupying the free space between this platform and the articulated structures of the crane. The latter then engage, in part, in the median recess of the counterweight.

During operations of unfolding or folding the crane, the connection made by the connecting rods between the ballast support and the lower mast element causes, simultaneously, the deployment of the mobile ballast upwards or its folding on the platform -form.

Such a mobile ballast device already meets the general purpose, which is to place, in the position of use, the counterweight quite far from the axis of vertical orientation of the crane, to produce a moment of high stability, while folding the ballast for the transport of the crane, in particular its transport on road.

However, the particular embodiment described in the document EP 0508907 A1 retains disadvantages or inadequacies.

In particular, the solution proposed by this document is only suitable for an embodiment with a central strut mast training. It is not directly transferable to a crane which, in a more usual way, has two side mast mast shrouds; indeed, in this case, there would be interference between the shrouds and connecting rods, during the lifting of the crane and therefore the mobile ballast.

It also appears that the lowering of the mobile ballast horizontally, as provided for in EP 0508907 A1 is not possible in all cases and, in particular, when the rotating platform also supports, in its central part, a cabinet that contains various equipment, including electrical crane.

Furthermore, the mounting of the counterweight on a support, which is itself articulated to the platform, causes a complication of the structure of the mobile ballast device, without providing any particular advantage. In particular, this method of mounting the counterweight does not optimize, in the lowered transport position, the situation of the mobile ballast relative to the wheels by which the crane is carried and towed on the road.

The present invention aims to avoid all the disadvantages previously described, and is therefore intended to improve the device considered mobile ballast for tower crane, in particular to adapt it to foldable cranes with lateral stays, while keeping a simple structure, and optimizing the raised and lowered positions of the counterweight, taking into account the environment of this counterweight.

To this end, the subject of the invention is a transportable tower crane with a mobile ballast device, of the kind in question here, that is to say constituted of a counterweight connected by articulation to the rear part of a platform. rotating form of the crane and also connected in an articulated manner, via at least one connecting rod, to an element of a foldable and foldable mast of the crane, so that in the unfolded position of use of the crane, the counterweight is straightened substantially vertically above the rear portion of the turntable, while in the folded transport position of the crane the counterweight is folded over the turntable, which tower crane is essentially characterized in that the counterweight is, on the one hand, articulated to the rear part of the rotating platform by means of lateral elements extending substantially perpendicular to the longitudinal direction of said counterweight, and in that this counterweight is, on the other hand, hingedly connected, via the rod or rods, to the upper element of the foldable and collapsible mast.

In one embodiment of the transportable tower crane according to the invention, the counterweight is articulated to the rear part of the rotating platform by means of two elongate triangular side plates, integral with this counterweight, the axis of articulation located at the tip of these plates.

Thus, an essential characteristic of the crane according to the present invention resides the particular mode of articulation of the counterweight on the rotating platform, which allows, in the position of use, to bring the counterweight into a position as far as possible from the axis of rotation of the crane, to produce a moment of high stability. Indeed, the plates by which the counterweight is articulated on the platform allow to shift back the center of gravity of the ballast, relative to their articulation, a distance equal to the sum of the half-height of the counterweight and the length of these plates. Furthermore, the use of such plates allows a direct articulation of the counterweight on the platform, without the need for a particular support shaped frame.

In addition, thanks to the configuration recommended by the invention, in the folded transport position the counterweight is brought back above the crane's running axle on the ground, which limits the load on it and allows to obtain an action of the towing shaft of the crane, exerted on the tractor truck, which is oriented towards the ground.

According to an advantageous characteristic of the crane according to the invention, in the folded transport position, the counterweight has an inclined general orientation, rising from the rear towards the front relative to the rotating platform. In this particular folded position, the counterweight can in particular be folded over a cabinet in the central part of the rotating platform, while occupying a sufficiently low height.

However, in another form of construction, the counterweight can also, in the transport position, be folded horizontally above the rotating platform.

Advantageously, the counterweight is composed of two separate lateral blocks disposed respectively above the two longitudinal sides of the rotating platform, which allows the articulated structure of the crane to lower in the folded position, between these two blocks. . Thus, the inclined transport position of the counterweight does not constitute an obstacle to the complete folding of the crane.

Finally, the fact that the counterweight is connected by connecting rods to the upper mast element (and no longer to the lower mast element) reduces the efforts during folding and unfolding. During these operations, the interference between the connecting rods on the one hand, and the side mast side shrouds on the other hand, which move in parallel vertical planes, is easily avoided for example by providing, on the upper mast member, lateral spacers which are articulated rods which shift outwardly the planes of movement of these rods relative to the mast mast shrouds of travel plans occupy here an "inner" position.

Thus, the mobile tower crane with mobile ballast device, object of the present invention, overcomes all the disadvantages or shortcomings of the device known in the state of the art.

• Figure 1 est une vue partielle, en perspective, d'une grue à tour équipée d'un dispositif de lest mobile, conforme à la présente invention, en position d'utilisation ;
• Figure 2 est une vue de côté de la grue en position d'utilisation, en correspondance avec la figure 1 ;
• Figure 3 est une vue de côté similaire à la figure 2, montrant cette grue en position partiellement repliée ;
• Figure 4 est une autre vue de côté, similaire aux précédentes, montrant la même grue en position repliée de transport, avec le contrepoids rabattu.

The invention will be better understood with the aid of the description which follows, with reference to the appended schematic drawing representing, by way of example, an embodiment of this transportable tower crane with a mobile ballast device:

• Figure 1 is a partial view, in perspective, of a tower crane equipped with a mobile ballast device, according to the present invention, in the use position;
• Figure 2 is a side view of the crane in the use position, in correspondence with Figure 1;
• Figure 3 is a side view similar to Figure 2, showing this crane in the partially folded position;
• Figure 4 is another side view, similar to the previous, showing the same crane in the folded transport position, with the counterweight folded.

In all the figures, the tower crane is shown without indication of its arrow, which is not concerned by the present invention.

This tower crane comprises at its base a fixed frame 1 on which is pivotably mounted, about a vertical axis, a rotating frame or a rotating platform 2.

The crane comprises a folding foldable mast 3, which is composed of a lower mast element 4 and an upper mast element 5. The lower mast element 4 is articulated by its base, about a horizontal axis 6, on the rotating platform 2, towards the front thereof. The upper mast element 5 is articulated by its base, around a horizontal axis 7, at the top of the lower mast element 4. The boom (not shown) of the crane is itself carried, articulated way by the top of the upper mast element 5.

The rotating platform 2 here includes, in its central part, a cabinet 8 between the two lateral parts of which is pivotally mounted the lower mast element 4.

The crane comprises two lateral mast struts 9, mounted between the rotating platform 2 and the mast 3. More particularly, each shroud 9 is hinged, on the one hand, at a point 10 situated on the rear of the mast. the cabinet 8 and, secondly, at a point 11 located on the upper mast element 5.

The two stays 9 are associated with a motorized control device for unfolding and folding the mast 3, which device is composed of a linkage 12 located in the region of the intermediate articulation (axis 7) of the mast 3, and a single cylinder 13 connecting the linkage 12 to an intermediate point 14 of the lower mast element 4. The linkage 12 comprises, on each side of the region of the intermediate hinge of the mast 3, two connecting rods respectively articulated to the two elements of mast 4 and 5.

The crane further comprises a rear tie rod, not shown, which connects the rear portion of the rotating platform 2 to the arrow, to ensure the retention thereof. This rear tie also controls the unfolding of the boom simultaneously with the unfolding of the mast 3 controlled by the device composed of the linkage 12 and the jack 13.

The crane comprises a mobile ballast device, designated as a whole by the reference 15.

The mobile ballast device 15 comprises a counterweight, which consists of two separate lateral blocks 16, arranged respectively above on both longitudinal sides of the rotating platform 2, in a symmetrical arrangement with respect to the vertical median plane of this platform. A central free space 17 is thus formed between the two constituent blocks 16 of the counterweight.

The counterweight, consisting of the two blocks 16, is articulated to the rear part of the rotating platform 2 by means of two lateral plates 18, of elongated triangular shape, which extend substantially perpendicular to the longitudinal direction of this counterweight . The axis of articulation, thus connecting the counterweight to the rotating platform 2, is a horizontal axis 19 which is located at the tip of the plates 18.

The portion of the counterweight furthest from these plates 18 is connected, by two lateral rods 20, to the upper mast element 5. More particularly, the two rods 20 are parallel and each connect one of the side blocks 16 of the counterweight to one side of the upper mast element 5. One end of each rod 20 is hingedly connected at a point 21 to the corresponding side block 9 while the other end of this rod 20 is articulated on a spacer lateral 22 carried by the upper mast element 5, in particular welded to this mast element. The positions of the hinge points 21, and the spacers 22, offset the vertical planes of displacement of the two rods 20 outwardly, relative to the vertical displacement planes of the two shrouds 9. The latter thus occupy an "inner" position , avoiding any interference between the stays 9 on the one hand, and the connecting rods 20 on the other hand.

Thanks to the structure of the mobile ballast device 15, the counterweight consisting of the two blocks 16 is pivotally movable about the axis 19 between a rectified position of use (FIGS. 1 and 2) and a folded position of transport ( FIG. 4), passing through intermediate positions such as that of FIG. 3. Unfolding or folding the mast 3 of the crane, controlled by the jack 13 associated with the linkage 12, is used to straighten the counterweight. (Blocks 16) and bring it to the position of use, or to fold it back to the working position, by means of the connecting rods 20.

More particularly, in the upright position of use (FIGS. 1 and 2), the two triangular lateral plates 18 extend substantially horizontally towards the rear of the hinge axis 19, which shifts the center of gravity counterweight (blocks 16) rearwardly, relative to the hinge axis 19, by a distance equal to the sum of the half height of the 16 blocks and the length of a plate 18. It is therefore understandable to achieve a high counterweight, and long plates 18.

In the folded transport position (FIG. 4), the counterweight (blocks 16) has a general orientation inclined at an angle A, which may be of the order of 30 °, relative to the horizontal, the counterweight rising from the rear towards the front relative to the rotating platform 2. In this inclined position, the blocks 16 constituting the counterweight are folded on the cabinet 8 present in the central part of the rotating platform 2. The articulated structure crane, including its arrow not shown here, is lowered between the two blocks 16, and thus takes place in the central free space 17.

• en modifiant les détails de forme du dispositif de lest mobile, par exemple du contrepoids et de ses plaques d'articulation ;
• en réalisant une inversion de position entre les haubans et les bielles, c'est-à-dire en disposant les deux bielles intérieurement et les deux haubans extérieurement ;
• en positionnant le contrepoids non pas dans une orientation inclinée, mais à l'horizontale, dans la position rabattue de transport, l'orientation inclinée n'étant ici que la conséquence de la position et de la configuration de l'armoire de la plate-forme tournante ;
• éventuellement, en réalisant le contrepoids sous la forme d'un bloc unique, le cas échéant avec une seule bielle reliant ce contrepoids au mât ;
• en appliquant l'invention à des grues transportables pouvant posséder toutes particularités.

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

• by modifying the shape details of the mobile ballast device, for example the counterweight and its hinge plates;
• by performing a reversal of position between the stays and the connecting rods, that is to say by arranging the two connecting rods internally and the two shrouds externally;
• by positioning the counterweight not in an inclined orientation, but horizontally, in the folded transport position, the inclined orientation being here only the consequence of the position and the configuration of the cabinet of the platform. rotating form;
• possibly, realizing the counterweight in the form of a single block, if necessary with a single connecting rod connecting the counterweight to the mast;
• applying the invention to transportable cranes that can have any particularities.

Claims (8)

Portable tower crane with mobile ballast device (15), the device (15) consisting of a counterweight (16) hinged (19) to the rear part of a rotating platform (2) of the crane , and also hingedly connected, via at least one connecting rod (20), to an element of a folding and folding mast (3) of the crane, such that in the unfolded position of use of the crane, the counterweight (16) is straightened substantially vertically above the rear portion of the rotating platform (2), whereas in the folded transport position of the crane, the counterweight (16) is folded over the rotating platform (2), characterized in that the counterweight (16) is articulated on the one hand to the rear part of the rotating platform (2) via side members (18) extending substantially perpendicular to the longitudinal direction of said counterweight (16), and that said counterweight (1) 6) is, on the other hand, connected in an articulated manner, via the rod or rods (20), to the upper element (5) of the folding and folding mast (3). Transportable tower crane according to Claim 1, characterized in that the counterweight (16) is articulated to the rear part of the rotating platform (2) via two elongated triangular side plates (18), integral with each other. counterweight (16), the hinge axis (19) being at the tip of these plates (18). Transportable tower crane according to claim 1 or 2, characterized in that in the folded transport position the counterweight (16) has an inclined general orientation (A) rising from the rear towards the front relative to the rotating platform (2). Transportable tower crane according to claim 3, characterized in that the counterweight (16) is folded over a cabinet (8) in the central part of the rotating platform (2). Transportable tower crane according to claim 1 or 2, characterized in that in the transport position the counterweight (16) is folded horizontally above the rotating platform (2). Transportable tower crane according to one of Claims 1 to 5, characterized in that the counterweight is composed of two separate side blocks (16), respectively arranged above the two longitudinal sides of the rotating platform (2). . Transportable tower crane according to Claim 6, characterized in that two parallel rods (20) are provided, each connecting one of the side blocks (16) of the counterweight to one side of the upper mast element (5). Transportable tower crane according to one of Claims 1 to 7, characterized in that on the upper mast element (5) there are lateral spacers (22) to which the connecting rods (20) are articulated and which offset outwardly the planes of movement of these connecting rods (20), relative to the planes of movement of mast struts (9) which occupy an "inner" position.

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