EP1927570A1 - Crane tower with counterweight - Google Patents

Abstract

The mast (4) has a ballast jib (15) with a rigid jib arm (16) articulated around a vertical axis on the mast. A slanted tie rod (17) connects the mast to a vertical end cap (22) of the arm, where the cap carries a pulley (25) for the passage of a cable (41) utilizable for lifting a concrete ballast block (14). The arm is coupled to an oriented hydraulic jack (31) possessing power supply such as hydro-electric power station (36), for allowing the jib to be motorized, autonomous and dismountable. A gas spring (23) pivots a rigid bar (19) relative to the arm in a predetermined direction.

Description

The present invention relates, in general, to the field of folding cranes. More particularly, this invention relates, for such cranes, an assembly consisting of the crane mast and a weight bracket associated with the mast, that is to say a bracket provided for the introduction and withdrawal, on the frame of the crane, stackable ballast blocks for stabilizing and balancing the crane in use thereof.

It is generally known to stabilize a construction crane by stacking more or less concrete ballast blocks on its fixed or rotating chassis.

In the case here considered folding cranes, automated assembly, the usual mode of transport of these cranes in the folded state is road transport on a trailer or a semi-trailer, which limits the total transportable weight. Thus, it is necessary to remove the ballast from the crane for transport, and to replace this ballast before commissioning the crane. These operations require dismantling or reassembly, one by one, the different ballast blocks.

To mount or dismount the ballast blocks without using an auxiliary crane independent of the crane concerned, various techniques have already been proposed.

A first solution, disclosed in the patent French FR 2306927 in the name of the Applicant, consists of a weight bracket that is mounted on the rotating platform of the crane, and which is connected by a halyard to the collapsible assembly constituted by the mast and the boom of the crane. Thus, the weight bracket uses here the driving force of the crane usually used for folding and unfolding the assembly consisting of the mast and the boom, and the device can not be considered as autonomous.

Another solution, described in the patent French FR 2490609 , consists of a ballast bracket attached to the mast of the crane, near its base, the mast being here telescopic. The cable and the winch which control the telescoping of the mast of the crane are, in this case, also used to operate the stem and thus manipulate the ballast blocks. Here again, the device is not autonomous. In addition it is necessary to position the ballast blocks by hand.

Also known is a self-erecting crane marketed by the Applicant under the name IGO28, and described in the documentation POTAIN 363-0200-032-0-FR, provided with a gallows weighting the cable is moved by the crane winch hoist, and which is equipped with a hydraulic steering mechanism. The steering mechanism is connected to the hydraulic power unit of the crane, which involves the realization of a long and complicated hydraulic circuit to take into account the folding of the crane and the telescoping of the mast. In addition, the steering cylinder of the stem being a small diameter cylinder while the hydraulic unit of the crane is designed to deliver a large fluid flow necessary to lift the crane, the rotating operation of the ballast bracket is somewhat progressive, which requires installing a flow limiter.

The present invention aims at eliminating the disadvantages of the various known solutions mentioned above, and its purpose is therefore to provide a device which makes it possible to automate as much as possible the weighting of a folding crane of the kind in question here, avoiding any manual intervention painful and dangerous, and also make the gallows self-ballast, so easily removable, and finally make the operation of this gallows more progressive, especially in its orientation movement.

For this purpose, the subject of the invention is essentially a crane mast with a ballast bracket, in particular for a collapsible construction crane, the weighting bracket intended for the handling of ballast blocks being, at least during use, fixed. to the mast or to an element thereof, said weighting bracket comprising a jib arm articulated about a vertical axis on the mast, and a tie rod which connects the mast to the front end of the jib arm, end which carries at least one pulley for the passage of a cable usable for lifting at least one ballast block, this assembly being characterized by the fact that, being of autonomous and removable design, the stem arm is coupled to a jack orientation with a power supply of its own.

In a preferred embodiment of the invention, the steering cylinder is a hydraulic cylinder, and its power supply is performed by a hydraulic unit belonging to the ballast bracket. The hydraulic unit can be carried by the rear end of the stem arm, for example by a hinge yoke provided at this end of the stem arm.

Thus, the steering movement of the ballast bracket is motorized by means of a jack which is made independent of the hydraulic unit and the hydraulic circuit of the crane, in particular by using a integrated hydraulic power station at the weighting bracket and sized according to the energy requirements of this stem. The hydraulic hoses that connect the control unit to the orientation cylinder can therefore be very short, and this cylinder operates very gradually. As the hydraulic unit is carried by the jib arm, disassembly of the ballast bracket, that is to say its separation from the mast of the crane, is also facilitated. The stem thus made easily removable can be used on several identical cranes.

According to an advantageous embodiment of the invention, the tie rod which connects the mast of the crane to the front end of the stem arm is composed of a flexible cable attached to the mast of the crane, and a rigid bar which extends the cable and is hinged to the front end of the stem arm. Advantageously, spring means, such as a gas spring, are associated with the articulation of the rigid bar of the tie rod with the front end of the arm of the bracket, said spring means tending to rotate the bar relative to the arm of gallows in a predetermined direction. Thanks to these provisions, a folding of the tie is effected and is even easier, during the folding of the crane, so as to simultaneously fold the arm of the bracket against the mast of the crane.

• Figure 1 est une vue d'ensemble, de côté, d'une grue repliable équipée d'un mât avec potence de lestage conforme à la présente invention ;
• Figure 2 représente, à échelle agrandie, un détail de la grue de figure 1, incluant une portion du mât et la potence de lestage ;
• Figure 3 représente, en vue de côté, un détail de l'extrémité antérieure du bras de potence ;
• Figure 4 représente, en perspective, un détail de la zone d'articulation du bras de potence sur le mât ;
• Figure 5 est une vue en perspective du mât et de la potence de lestage, celle-ci étant en cours d'utilisation ;
• Figure 6 est une vue de côté de la grue au cours d'une phase intermédiaire de repliage ;
• Figure 7 est une vue similaire à la figure 6, mais illustrant une phase ultérieure de repliage de la grue, la potence de lestage étant alors elle-même en cours de repliage.

The invention will be better understood from the description which quit, with reference to the attached schematic drawing showing, by way of example, an embodiment of the crane mast with ballast bracket.

• Figure 1 is an overall view, from the side, of a folding crane equipped with a mast with weighting bracket according to the present invention;
• Figure 2 represents, on an enlarged scale, a detail of the crane figure 1 , including a portion of the mast and the ballast bracket;
• Figure 3 represents, in side view, a detail of the front end of the jib arm;
• Figure 4 represents, in perspective, a detail of the articulation zone of the jib arm on the mast;
• Figure 5 is a perspective view of the mast and the weight bracket, the latter being in use;
• Figure 6 is a side view of the crane during an intermediate folding phase;
• Figure 7 is a view similar to the figure 6 but illustrating a subsequent phase of folding the crane, the weighting bracket then itself being folded.

The figure 1 represents, in side view, a folding tower crane, which comprises a fixed base frame 2, a rotating frame 3 which can be rotated relative to the fixed frame 2, a telescopic and foldable mast 4 made in two elements 5 and 6, and an arrow collapsible 7 made, in the example, in three successive deflection elements 8, 9 and 10. The lower element 5 of the mast 4 is hingedly connected to the rotating frame 3 by two front stays 11 and two rear shrouds 12 , while the rear end of the boom 7 is hinged to the top of the upper element 6 of the mast 4. An arrow retainer 13, here not detailed, holds the boom 7 in the horizontal position, in the working position crane that is to say when the mast 4 is erected vertically.

In the unfolded working position, the crane is stabilized and balanced by a ballast which results from the stacking, on the rotating frame 3, of a number of concrete ballast blocks 14, one of which is shown (in progress handling) on the figure 5 . To set up the ballast blocks 14 before the crane is put into service, and to remove these ballast blocks 14 before folding and transporting the crane, a ballast bracket 15 is provided which is associated with the mast 4 and, more particularly, to the lower element 5 of this mast.

The figures 2 , 3 and 4 represent, in particular, the structure of the weighting bracket 15.

This weighting bracket 15 comprises a rigid stem arm 16 whose rear end is hingedly connected to the mast element 5 and whose front end is connected by an oblique tie rod 17 to the same mast element 5. .

The tie rod 17 is composed of a flexible cable 18 and a rigid bar 19. The cable 18 is attached at a fixed point 20 to the mast element 5, in the upper part of this mast element. The bar 19, which extends the cable 18, is articulated about a horizontal axis 21 on a vertical end cap 22 of the stem arm 16. The end of the bar 19, which extends beyond the axis 21, is connected by a gas spring 23 to a point of the end yoke 22. This end cap 22 of the jib arm 16 carries a horizontal axis 24, on which is mounted freely rotatable a first pulley 25 (see in particular the figure 3 ).

At its posterior end (see in particular the figure 4 ), the jib arm 16 comprises another vertical clevis 26, which is articulated by a horizontal axis 27 on a support 28, itself pivotally mounted along a vertical axis 29 on the lower mast element 5, close to the one of the corner members 30 of this mast element 5.

A hydraulic steering cylinder 31, arranged horizontally on one side of the mast element 5, has a cylinder body 32 articulated at a fixed point 33 of this mast element 5, and a cylinder rod 34 which is hinged in a point 35 on a lateral arm of the pivoting support 28.

The rear clevis 26 of the jib arm 16 carries, in its upper part, a hydraulic unit 36 which comprises a pump unit with an electric motor powered by alternating current available on the crane or on the construction site. Two hydraulic hoses 37 and 38 connect the hydraulic unit 36 to the two chambers of the orientation cylinder 31. Thus, the actuation of the cylinder 31, made as a double-acting cylinder, makes it possible to orient the stem arm 16 by rotating its support 28 in one direction or the other around the vertical axis 29.

The rear clevis 26 of the jib arm 16 also carries a horizontal axis 39, on which is mounted freely rotating a second pulley 40.

For the use of the weighting bracket 15, as illustrated by figure 3 and especially the figure 5 , a cable 41 passes over the pulleys 25 and 40, the end of the cable 41 which hangs under the first pulley 25 having a hook 42 to which can be suspended, by means of slings 43, a block of ballast 14.

After passing over the second pulley 40 of the bracket 15, the cable 41 is directed downwards and then returned upwards by two other pulleys 44 and 45 located in the lower part of the mast element 5. Finally, The other end of the cable 41 is connected here by a hauling pulley 46 to the existing hoisting rope 47 of the crane, which is wound in a known manner around a drum of a hoist winch (not shown). The actuation of this winch moves the hoisting rope 47, which itself moves the cable 41 of the weighting bracket 15, so as to raise or lower the ballast block 14 suspended from the hook 42.

Thus, the combined operation of the hoist winch, and the orientation jack 31, makes it possible to move the ballast blocks 14 successively, for stack them on the rotating frame 3 of the crane or to remove them from this frame 3. In particular, the weighting bracket 15 makes it possible to remove all the ballast blocks 14, before proceeding to fold the crane itself prior to the transporting the crane on a trailer or semi-trailer.

In addition, Figures 6 and 7 illustrate, in two successive phases, the folding of the crane which is here accompanied by a folding of the weighting bracket 15. For folding the crane, after retracting the telescopic mast 4 and folding the arrow 7 on it -and even against the mast 4, we rock the assembly consisting of the arrow 7 and the mast 4 on the back, that is to say to the side previously occupied by the ballast, as illustrated by the figure 6 . The jib arm 16 then abuts against one of the rear shrouds 12.

As the tilting movement continues, the rigid bar 19 of the tie rod 17, pushed by the gas spring 23, tends to pivot about the axis 21 and finally comes into abutment on the jib arm 16, as shown in FIG. figure 7 . Then (in a manner not shown), the cable 18 of the tie rod 17 relaxes, and it is finally possible to complete the folding of the crane, the jib arm 16 being placed parallel to the mast 4 fully lowered.

Note also that, if desired or necessary, the ballast bracket 15 can be quickly dismantled, that is to say separated from the mast 4 of the crane, since it is linked to the mast 4 only at the level the point of attachment 20 of the cable 18 and at the level of the steering cylinder 31, this by means of connecting pins.

Although the invention has been described and illustrated in connection with a telescopic mast crane 4, it is readily conceivable that the same ballast device 15 may similarly be mounted on the lower member of a mast. folding crane, that is to say a mast consisting of two or more mast elements superimposed, articulated between them.

• en modifiant les détails de forme du dispositif, tels que les détails du bras de potence ;
• en ayant recours à tous moyens équivalents de ceux précédemment décrits, ceci concernant notamment le type d'énergie utilisable par le vérin d'orientation de la potence de lestage ; en particulier, si cette potence est prévue démontable, la seule énergie utilisable est en pratique l'électricité et l'on peut donc aussi envisager ici l'utilisation d'un vérin électrique ;
• en destinant une telle potence de lestage à des grues de tous types, et en utilisant cette potence avec tous moyens de suspension ou de préhension des blocs de lest à manipuler.

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

• modifying the shape details of the device, such as the details of the stem arm;
• by using any equivalent means of those described above, this particularly concerning the type of energy used by the steering cylinder of the ballast bracket; in particular, if this bracket is intended to be dismountable, the only usable energy is in practice electricity and we can also consider here the use of an electric cylinder;
• by destining such a weight bracket for cranes of all types, and using this bracket with any means of suspension or gripping of ballast blocks to handle.

Claims (5)

Crane mast with weighting bracket, in particular for collapsible construction crane, the weighting bracket (15) intended for the handling of ballast blocks (14) being, at least during use, fixed to the mast (4) or at a mast element (5) near the base thereof, said weighting bracket (15) comprising a jib arm (16) hinged about a vertical axis (29) on the mast (4), and a tie rod (17) which connects the mast (4) to the front end of the stem arm (16), which end carries at least one pulley (25) for the passage of a usable cable (41) for lifting at least one ballast block (14), characterized in that , the ballast bracket (15) being of autonomous and removable design, the stem arm (16) is coupled to an orientation cylinder ( 31) having a power supply (36) of its own. Crane mast with weighting bracket according to claim 1, characterized in that the steering cylinder is a hydraulic cylinder (31), and in that its power supply is provided by a hydraulic power unit (36) belonging to the stem ballast (15). Crane mast with weighting bracket according to Claim 2, characterized in that the hydraulic unit (36) is carried by the rear end of the jib arm (16), for example by a hinge clevis (26) provided in this end of the gallows arm (16). Crane mast with weight bracket according to one of claims 1 to 3, characterized in that the tie rod (17) connecting the mast (4) to the front end (22) of the stem arm (16) is composed of a flexible cable (18) attached to the mast (4) of the crane, and a rigid bar (19) which extends the cable (18) and which is articulated to the front end (22) of the jib arm (16). Crane mast with weight bracket according to Claim 4, characterized in that spring means, such as a gas spring (23), are associated with the hinge (21) of the rigid rod (19) of the tie rod (17) with the front end (22) of the jib arm (16), said spring means (23) tending to pivot the rod (19) relative to the jib arm (16) in a predetermined direction.

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