EP2123592B1 - Vorrichtung zum Einstellen der freien Drehfunktion eines Turmdrehkranes - Google Patents

Abstract

The mechanism has an orientation geared motor (8) including an internal main brake (12) that is deactivated when a tower crane is deactivated. Additional braking units are activated when the tower crane is deactivated for exerting a brake torque on a turning part (2) of a tower crane to avoid an uncontrolled rotation of the turning part, during setting vane. The additional braking units are incorporated in the geared motor, where the braking units are in a form of an internal annex brake (15) i.e. single brake disc, intercalated between a motor (10) and a reducer (11).

Description

The present invention relates, in general, to the technical field of tower cranes. More particularly, this invention relates to the steering mechanism of the rotating part of a tower crane, and even more specifically the device for winding the tower crane, which device is associated with the steering mechanism and which, in the case of the present invention, aims to facilitate the winding of the crane in a disturbed wind.

A tower crane is usually composed of two main parts, which are on the one hand a non-rotating vertical pylon also designated as "mast", and on the other hand a rotating upper part, that is to say orientable around a vertical axis of rotation. The rotating upper part, mounted at the top of the mast, is itself composed of an arrow, which extends on one side of the vertical axis of rotation of this rotating part, and a counter-flange equipped with a ballast, which extends on the other side of the vertical axis of rotation, so opposite the arrow. The rotation of the rotating part about this vertical axis is controlled by a motorized assembly, here designated as the orientation mechanism.

To mount the rotating part at the top of the mast of a tower crane, it is usually provided, interposed between the arrow and the counterpart of the rotating part, an orientation ring consisting of two concentric rings, with a ring stationary connected to the top of the mast and with a movable ring secured to the rotating part, rings between which are mounted rolling cylindrical balls or rollers.

To control the rotation of the thus mounted rotating part, the orientation mechanism usually comprises at least one electric geared motor integral with this rotating part, the moderator driving in rotation a pinion of vertical axis which is engaged with a gear wheel cut into the fixed ring of the orientation ring. Depending on the mechanical power to be transmitted to rotate the rotating part, one can mount one, two or more geared on the rotating part. The slewing ring is designed to allow rotation of the rotating part with minimal drive torque; nevertheless, it is necessary to exert between the considered parts of the crane a sufficient torque to overcome the friction of the balls or cylindrical rollers interposed between the fixed ring and the movable ring of the crown.

The geared motor orientation usually has an internal brake, controlled by an electromagnet. When the geared motor is stopped, the coil of the electromagnet is not electrically powered, and a braking torque is exerted. On the other hand, when the electromagnet is electrically powered, no braking torque is exerted by this brake. In case of plurality of orientation geared motors, at least one of them is equipped with such a brake, which occurs during the crane's working periods.

Outside of her work periods, so when she is "out of service", a tower crane is usually placed in a wind vane, that is to say that the rotating part of the crane is allowed to move freely according to the direction of the wind. The counterfleche is then placed against the wind, while the arrow is oriented in the direction of the wind, because the surface of the arrow which is exposed to the wind is greater than that of the counterfleche. Optionally, the surface of the arrow exposed to the wind is increased, for example by adding vertical plates in the arrow. To allow the crane to go into a wind vane, the operator cranks the brake on the steer motor when he leaves his workstation.

Such systems are described, for example, in patent documents FR 2135689 and EP1422188 .

However, when the tower crane is installed in a disturbed environment, with respect to the wind conditions, the speed and strength of the wind that hits the counter-flap can be very different from the speed and force of the wind that strikes simultaneously. the arrow. The difference between the torque applied to the boom and the torque applied to the counterfleche then becomes much greater than the friction torque of the slewing ring, so that the rotating part of the crane, instead of positioning itself in the direction of the wind, will start to turn in a certain direction, without stopping. As a result, the crane fails to prop up properly, and its rotating part is driven in an uncontrolled rotation. Under such conditions, there is a risk of falling of the crane, especially if a gust of wind hits the rotating part when this part is oriented perpendicular to the direction of the wind.

Such disturbed conditions may arise in particular if the crane is located in an urban site in which neighboring high-rise buildings create an influence, or in natural sites such as near a cliff or in a steep valley, or still near power plant cooling towers, and other similar situations.

To prevent the uncontrolled rotation of the rotating part of a tower crane when it is installed on such a site, subject to disturbed winds, so to avoid the risk of the crane falling, it has already been proposed a a solution which consists in inserting an additional brake in the steering mechanism which, when placing the crane in the wind vane, exerts a permanent braking torque, sufficient to prevent uncontrolled rotation of the rotating part, while leaving the canvassing possible. This solution has been described in the French patent application 07.05817 of 10 August 2007, published under number FR 2 919 853 , and in the corresponding European patent application 08356064.9 of 24 April 2008, published under number EP 2025637 , in the name of the Applicant.

According to these documents, the proposed solution consists, in the case of an orientation mechanism comprising at least two geared motors, to provide a geared motor with main brake used for the normal work of the crane, and another geared motor that is equipped with the brake additional for braking the rotating part when the crane is out of service, to ensure proper wind vane.

This solution has the disadvantage of being unique for a construction site and for a crane and, because it imposes modifications of a crane resulting from mass production, it makes it necessary to bring the crane into conformity with the crane. end of a construction site. In addition, this solution is not suitable for the case of a single gear motor orientation, unless to add to the output of the gearmotor an additional external brake which, too, requires a significant transformation of the crane.

The present invention aims to eliminate these disadvantages, and is therefore intended to provide an alternative solution to the problem of the uncontrolled rotation of the rotating part of the crane in case of disturbed wind, a solution that does not require any modification of a crane. series and which is easily transposable from one site to another, and which is also a suitable solution for cranes whose orientation mechanism has a single geared motor.

To this end, the subject of the present invention is a mechanism for orienting the rotating part of a tower crane, with a device for vane winding of the tower crane, the mechanism comprising at least one Geared motor gearbox with motor and gearbox, and with internal main brake deactivated when the crane is taken out of service, as well as additional braking means that can be activated when the crane is put out of operation to operate on the rotating part of the crane. a braking torque preventing an uncontrolled rotation of said rotating part during winding, this orientation mechanism being essentially characterized by the fact that the additional braking means are incorporated in the geared motor or in one of the geared motors, under the form of an internal auxiliary brake interposed between the motor and the gearbox.

In a preferred embodiment of the invention, the internal secondary brake, interposed between the motor and the gearbox, is a single disc brake controlled by an electromagnet, this brake being electrically powered so as not to slow the rotation. of the rotating part of the crane when the crane is in service, but exerting a braking torque by means of spring means when not electrically powered, so as to avoid the uncontrolled rotation of the rotating part of the crane. the crane when it is put in wind vane.

Thus, the solution of the invention consists in the addition, in the single geared motor or in one of the geared motors of the orientation mechanism, of an electromechanical assembly possibly dismountable composed of a brake, its electrical box and its wiring harness, the device being able to brake an internal shaft of the gearmotor, thus to brake the rotating part of the tower crane, being operational when the crane is put in wind vane. Conversely, this auxiliary brake must not slow the rotation of the rotating part when the crane is in service, only the main brake occurring during the work of the crane. The choice of a single disk brake with electromagnetic control constitutes here a particularly advantageous solution from the point of view of the constructive simplicity, the bulk and the control.

Advantageously, the auxiliary brake is designed to exert an adjustable braking torque. In particular, if it is a disc brake controlled by an electromagnet and biased in the direction of braking by spring means, these means preferably take the form of compression springs acting axially on a disc reinforcement, the compression of the springs or of certain springs being adjustable by screwing an adjusting ring. Thus, the solution according to the present invention is easily transposable from one site to another site also involving a risk of uncontrolled rotation of the rotating part of the crane, because it allows easy adjustment of the braking torque exerted on this rotating part when the crane is out of service. The device of the invention even allows use on a construction site without disturbed wind, this without disassembly of the auxiliary brake, if the braking torque of the auxiliary brake can be set to zero, ie if the springs can be relaxed to such point that they no longer solicit the brake disc.

• Figure 1 est un schéma illustrant, dans une vue en plan par dessus, l'action du vent sur la partie tournante d'une grue à tour;
• Figure 2 est une vue partielle, de côté, de la partie tournante et en particulier du mécanisme d'orientation d'une grue à tour, équipée du dispositif selon l'invention ;
• Figure 3 représente, très schématiquement, le dispositif de l'invention et en particulier le motoréducteur équipé du frein annexe ;
• Figure 4 est une vue de détail, en coupe, de ce frein dans une forme de réalisation particulière.

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 device for vane winding a tower crane;

• Figure 1 is a diagram illustrating, in a plan view from above, the action of the wind on the rotating part of a tower crane;
• Figure 2 is a partial view, from the side, of the rotating part and in particular of the steering mechanism of a tower crane equipped with the device according to the invention;
• Figure 3 represents, very schematically, the device of the invention and in particular the geared motor equipped with the auxiliary brake;
• Figure 4 is a detail view, in section, of this brake in a particular embodiment.

Referring to figures 1 and 2 , the rotating part 2 of a tower crane consists of an arrow 3 and a counter-flange 4, aligned on either side of an orientation ring 5 of vertical axis which overcomes the vertex 6 of the mast (not shown itself) of the crane. The ring 5 itself consists of two rings, a fixed ring connected to the top 6 of the mast, and a movable ring connected to the rotating part 2, the fixed ring forming an outer gear 7. A geared motor 8, secured to the rotating part 2, is coupled to a pinion 9 of vertical axis A, which meshes with the toothed wheel 7 - see also the figure 3 .

In a known manner, as shown by figure 3 , the geared motor 8 comprises an electric motor 10, a gear reducer 11 and an internal main brake 12, placed here above the motor 10. Above the main brake 12 is provided a wind vane device 13, itself surmounted by An encoder 14. The wind vane device 13 makes it possible to mechanically lock the main brake 12 in the unbraked position, when the crane is out of service, so that the rotating part 2 can orientate itself. in the direction of the wind. When the crane is in operation, the main brake 12 is automatically actuated while the engine 10 is not powered, and thus constitutes a service brake.

According to the invention, an auxiliary brake 15 is interposed between the output of the electric motor 10 and the input of the gear 11 inside the geared motor 8. The auxiliary brake 15 comes into action only when the crane is put out of service, to exert a braking torque on the rotating part 2, and thus avoid an uncontrolled weather vane in case of disturbed wind. In practice, at the end of his working day, the crane operator puts the crane in a wind vane by disabling the main brake 12 of the geared motor 8 and then activating the auxiliary brake 15 to allow him to exert his braking torque.

• un couple Cfl appliqué par le vent sur la flèche 3, et
• un couple Ccf appliqué par le vent sur la contreflèche 4.

Referring again to the figure 1 , a wind of a certain speed and direction, indicated by the arrow V, exerts on the rotating part 2 of the crane considered two pairs of opposite directions, namely:

• a torque Cfl applied by the wind on the arrow 3, and
• a Ccf couple applied by the wind on the counterfleche 4.

In addition, a friction torque Ccou is to be considered at the level of the crown 5 of orientation of the rotating part 2.

dans laquelle Cfl₁ et Ccf₁ représentent les couples appliqués par un vent de vitesse V1 respectivement à la flèche 3 et à la contreflèche 4.The main brake 12 must take the difference in torque between the arrow 3 and the counter-flap 4, taking into account the friction torque, up to a maximum wind speed V1 defined by the standards, for example a speed of 72 km / h. . Thus, the braking torque Cfr ₁ for such a wind speed V1, to be exerted by this brake 12, must satisfy the relation: $${\mathrm{cf.}}_1>{\mathrm{cfl}}_1-{\mathrm{ccf}}_1-\mathrm{Ccou}$$

in which Cfl ₁ and Ccf ₁ represent the couples applied by a wind of speed V1 respectively to the arrow 3 and to the counterfleche 4.

dans laquelle :

• Cfl₂ représente le couple appliqué à la flèche 3 par un vent d'une certaine vitesse V2 inférieure à la vitesse maximale V1,
• Ccf2 représente le couple appliqué à la contreflèche 4 par le même vent de vitesse V2 inférieure à la vitesse maximale V1,
• Ccou représente comme précédemment le couple de frottement de la couronne 5.

The braking torque noted Cfr ₂ , exerted by the auxiliary brake 15 to prevent the uncontrolled rotation of the rotating part 2 of the crane in a disturbed wind, is given by the following formula: $$\mathrm{<figure-callout\; id="2"\; label="Cf\; \; r"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">Cf\; </figure-callout>}{\mathrm{r}}_{}{\mathrm{}}_{\mathrm{2}}=\mathrm{Cf}{\mathrm{l}}_{\mathrm{2}}\mathrm{-}\mathrm{CC}{\mathrm{f}}_{\mathrm{2}}\mathrm{-}\mathrm{Ccou}$$

in which :

• Cfl ₂ represents the torque applied to the boom 3 by a wind of a certain speed V2 lower than the maximum speed V1,
• Ccf2 represents the torque applied to the counterfleche 4 by the same wind velocity V2 lower than the maximum speed V1,
• Ccou represents as previously the friction torque of the crown 5.

The wind speed V2 is for example equal to 55 km / h (whereas, in the case taken here for example, the speed V1 is equal to 72 km / h).

To obtain the braking torque Cfr ₂ respecting the relationship indicated, it is sufficient to use an auxiliary brake 15 provided with one or more springs whose expansion force gives the desired torque value.

The figure 4 illustrates in more detail the structure of the internal auxiliary brake, and allows to understand its operation, in the case of a particular embodiment where the brake 15 is a single disc brake and electromagnet controlled.

On the figure 4 , reference 16 designates an internal shaft to the geared motor 8, constituting both the output shaft of the motor (not shown - located on the right) and the input shaft of the gearbox (not shown - located on the left). The shaft 16 passes freely through a flange 17, and carries a rotor 18 composed of a central hub 19, wedged on the shaft 16, and an annular disc 20 provided with gaskets 21 at its periphery, on both sides.

On the side facing the engine, the auxiliary brake 15 comprises, coaxially with the shaft 16, an electromagnet 22 comprising a coil 23 and a fixed inductor body 24, which is assembled by means of hollow screws 25 to the flange 17 A non-rotating armature disc 26 is mounted between the inductor body 24 and the disc 20 around the hub 19, the armature disc 26 being freely traversed by the hollow screws 25.

Springs 27 and 28 are housed in bores of the inductor body 24. The springs 27, at "external" disposition, are compression coil springs housed in blind bores and supported, at one end, on one face of the disk of The other springs 28, in "internal" disposition, are compression coil springs housed in through bores and supported, at one end, on the same face of the armature disk 26 as the preceding springs 27.

An adjusting ring 29, located on the motor side, has a threaded hub 30 screwed into the central opening of the inductor body 24, and a flange 31 which, by means of small pistons 32, presses on the ends (opposite the disc 26) of the springs 28.

The hollow screws 25 make it possible to adjust the air gap E which separates, in the braked position, the armature disk 26 from the inductor body 24, so that the coil 23 can correctly attract this disk 26 and release the brake 15. The adjustment ring 29 allows adjustment of the braking torque to the desired value. By screwing this adjusting ring 29 into the inductor body 24, the length of the "inner" springs 28 is reduced, the springs 28 being further compressed. Consequently, these springs 28 apply a greater force to the armature disk 26, which itself transmits this force to the disk 20 of the rotor 18, so that the braking torque is increased.

When the crane is in wind vane, the coil 23 of the electromagnet 22 is not powered, so that the armature disk 26 is no longer attracted magnetically to the inductor body 24. The springs 27 and 28 axially pushing the armature disc 26 towards the disc 20 of the rotor 19, so that the shaft 16 is braked. Any rotational movement of the rotating part 2 of the crane tends to be transmitted by the toothed wheel 7 and the gear 11 to the shaft 16 but the latter is braked by the auxiliary brake 15. When the crane is in use, the electromagnet 22 of this brake 15 is activated and it attracts the armature disc 26 by compressing the springs 27 and 28, thereby loosening the disc 20 of the rotor 19. The steering torque produced by the motor 10 "crosses Then the brake 15, through the shaft 16, to be transmitted to the gear 11.

Adjustment of the auxiliary brake 15, made by screwing or loosening more or less the adjusting ring 29, makes it possible to cover a wide range of braking torques, for example between 4 Nm and 40 N.m. According to an advantageous possibility, the braking torque of the auxiliary brake 15 can be canceled, which allows a use of the device on a construction site where there is no risk of disturbed wind. The adjustment of the braking torque is also possible, in part, by modifying the number of springs acting on the armature disc 26.

• en remplaçant le frein annexe interne à disque, et à commande par électro-aimant, par un frein d'un autre type, également capable d'exercer un couple de freinage sur la partie tournante mise en girouette ;
• en appliquant l'invention à un mécanisme d'orientation de grue à tour possédant des motoréducteurs en nombre quelconque, auquel cas le frein annexe équipe soit un seul des motoréducteurs, soit plusieurs de ces motoréducteurs.

It is not departing from the scope of the invention, as defined in the appended claims:

• by replacing the internal brake disc brake, and electromagnetically controlled by a brake of another type, also able to exert a braking torque on the rotating part set in wind vane;
• by applying the invention to a tower crane steering mechanism having geared motors in any number, in which case the auxiliary brake equips either a single geared motor or several of these geared motors.

Claims (5)

1. A mechanism for slewing the rotating part (2) of a tower crane, with a device for placing the tower crane in weathervaning mode, the mechanism comprising at least one slewing geared motor unit (8) with a motor (10) and a reduction gear (11), and with an internal main brake (12) which is deactivated when the crane is placed out of service, and also additional braking means (15) which can be activated when the crane is placed out of service in order to exert on the rotating part (2) of the crane a braking torque (Cfr₂) which avoids uncontrolled rotation of said rotating part when placed in weathervaning mode, characterized in that the additional braking means are incorporated in the geared motor unit (8) or in one of the geared motor units in the form of an internal auxiliary brake (15) interposed between the motor (10) and the reduction gear (11).
2. The slewing mechanism as claimed in claim 1, characterized in that the internal auxiliary brake (15), interposed between the motor (10) and the reduction gear (11), is a single disk brake (20) controlled by an electromagnet (22), this brake (15) being supplied electrically so as not to brake the rotation of the rotating part (2) of the crane when the crane is in service, but exerting a braking torque by way of spring means (27, 28) when it is not supplied electrically, thereby avoiding uncontrolled rotation of the rotating part (2) of the crane when it is placed in weathervaning mode.
3. The slewing mechanism as claimed in claim 1 or 2, characterized in that the auxiliary brake (15) is designed to exert an adjustable braking torque (Cfr₂).
4. The slewing mechanism as claimed in claims 2 and 3 together, characterized in that, with the auxiliary brake (15) being a brake controlled by an electromagnet (22) and urged in the direction of braking by spring means, these means take the form of compression springs (27, 28) acting axially on an armature disk (26), the compression of the springs or of certain springs (28) being adjustable by screwing an adjusting ring (29).
5. The slewing mechanism as claimed in claim 3 or 4, characterized in that the braking torque (Cfr₂) of the auxiliary brake (15) can be canceled.

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