EP3466862B1 - Lifting boom crane with boom locking device in raised configuration - Google Patents

Description

The present invention relates to a lifting jib crane, and in particular to a lifting jib tower crane. In addition, the present invention relates to a luffing jib crane provided with a lifting cylinder capable of acting on the jib in order to move it in raising and lowering. Furthermore, the present invention relates to a method for locking a lifting boom in a raised safety configuration.

The present invention applies to the field of tower cranes comprising a lifting boom. The present invention can be applied to several crane structures, for example to structures composed of trellis and members.

It is known, in particular from the document WO 2017/109309 , a lifting jib crane provided with a lifting cylinder, this lifting cylinder comprising a jack body mechanically connected to a structural element of the crane and a movable rod articulated on the lifting jib, where the movable rod is movable in the actuator body enters at least one deployed position and at least one retracted position for moving the lifting boom in raising and lowering between at least one raised configuration and at least one lowered configuration.

For safety reasons, and in particular in the event of strong winds, it is recommended, even compulsory, to make a vane of the boom, by disengaging the boom (in other words by unlocking the orientation brakes) so that '' it is free to rotate to automatically orient itself in the direction of the wind and thus allow the crane to be left without human supervision. In the case of a luffing jib crane, the vane is made with the jib in a raised safety configuration corresponding to a configuration precise enough to minimize the turning radius of the jib and thus prevent the jib, in weather vane, fly over areas near the construction site, such as traffic lanes, buildings, ...

Furthermore, and always for reasons of safety and / or compliance with local standards or regulations, provision can be made for the boom to be maintained in a raised safety configuration even in service, when the crane is handling a load, in order to '' prevent the boom and the suspended load from flying over such areas near the site.

Thus, to comply with such safety requirements, it is essential to guarantee that the boom remains in the raised configuration security, to avoid overflight of prohibited areas, even for very long periods, which can range up to several months without surveillance.

When the boom is placed in a wind vane, the wind pushes from behind on the boom, generating significant forces on the lifting cylinder, and it is therefore essential that the lifting cylinder does not deform, and in particular does not not compress, at the risk of seeing the arrow lower and therefore fly over the prohibited areas.

Furthermore, the lifting or lowering movement of the boom is carried out by the lifting cylinder, which can be a hydraulic or electric cylinder. This lifting cylinder is always connected between the structural element and the boom, which has the consequence of controlling the movement of the boom in the direction of ascent (in lifting) and also in the direction of descent (in lowering).

However, in the particular case of a crane with a hydraulic lifting cylinder, when the boom must be held in the raised safety configuration, the boom is well retained in both directions thanks to the lifting cylinder, but fluid leaks hydraulic and / or hydraulic fluid expansion phenomena can cause compression of the lifting cylinder (in other words a retraction of the movable rod), which would cause an uncontrolled and undesired lowering of the boom which can be particularly detrimental if the boom is weather vane; such hydraulic fluid leaks can be both internal to the lifting cylinder and external to the joints or hoses of the hydraulic system.

The object of the present invention is in particular to solve all or part of the aforementioned drawbacks, by proposing a locking device which guarantees a blocking of the lifting boom in the raised safety configuration, whatever the external conditions, even during long periods where the boom is placed in a weather vane in the raised safety configuration without human control.

Thus, the invention aims to guarantee a fixed reach of the boom to meet the prohibitions on overflying areas near the site, even under high wind conditions.

• une position de libération dans laquelle l'entretoise est déportée vis-à-vis du vérin de relevage de sorte que sa partie distale est écartée du vérin de relevage, autorisant la tige mobile à être déplacée dans le corps de vérin et à agir sur le déplacement de la flèche relevable ; et
• une position de verrouillage dans laquelle l'entretoise est rabattue sur le vérin de relevage de sorte que la butée est apte à venir en appui sur le corps de vérin.

To this end, it offers a crane comprising a lifting boom and a lifting cylinder, this lifting cylinder comprising a cylinder body mechanically connected to a structural element of the crane and a movable rod. articulated on the lifting jib, where the movable rod is movable in the cylinder body between at least one deployed position and at least one retracted position to move the lifting jib in raising and lowering between at least one raised configuration and at least one configuration lowered, this crane being remarkable in that it further comprises a locking device capable of cooperating with the lifting cylinder to mechanically lock the movable rod in a deployed safety position and thus block the lifting boom in a raised safety configuration , where this locking device comprises a spacer provided with a proximal part articulated on the arrow and with a distal part supporting a stop, where this spacer is pivotally movable on the arrow between:

• a release position in which the spacer is offset vis-à-vis the lifting cylinder so that its distal part is spaced from the lifting cylinder, allowing the movable rod to be moved in the cylinder body and to act on the moving the lifting boom; and
• a locking position in which the spacer is folded down on the lifting cylinder so that the stop is able to come to bear on the cylinder body.

• dans une première phase ou phase de service, l'entretoise est en position de libération et la tige mobile est libre d'être déplacée dans le corps de vérin pour agir sur le déplacement de la flèche relevable ;
• dans une deuxième phase ou phase de transition, la tige mobile est déployée jusqu'à une position déployée de transition, au-delà de la position déployée de sécurité, et l'entretoise est déplacée jusqu'à sa position de verrouillage en étant rabattue sur la tige mobile ;
• dans une troisième phase ou phase de verrouillage, la tige mobile est rétractée de la position déployée de transition vers la position déployée de sécurité jusqu'à ce que la butée soit en appui sur le corps de vérin pour que l'entretoise maintienne fixement la tige mobile dans la position déployée de sécurité pour verrouiller la flèche relevable dans la configuration relevée de sécurité.

With the invention, the lifting boom is locked in the safety raised configuration according to the following locking sequence:

• in a first phase or service phase, the spacer is in the release position and the movable rod is free to be moved in the cylinder body to act on the movement of the lifting jib;
• in a second phase or transition phase, the movable rod is deployed to a deployed transition position, beyond the deployed safety position, and the spacer is moved to its locking position by being folded over the movable rod;
• in a third phase or locking phase, the movable rod is retracted from the deployed position of transition to the deployed security position until the stop is in abutment on the jack body so that the spacer fixes the rod securely movable in the deployed safety position to lock the lifting boom in the raised safety configuration.

Thus, this locking device with pivoting spacer makes it possible to precisely block the boom in the raised configuration of safety, so that the crane can in particular be put on a wind vane (that is to say free to rotate to orient itself automatically in the direction of the wind).

• un premier capteur détectant la présence de l'entretoise en position de libération ;
• un deuxième capteur détectant la présence de l'entretoise en position de verrouillage ;
• un troisième capteur détectant la présence de la butée en appui sur le corps de vérin.

Advantageously, the locking device further comprises:

• a first sensor detecting the presence of the spacer in the release position;
• a second sensor detecting the presence of the spacer in the locked position;
• a third sensor detecting the presence of the stop bearing on the cylinder body.

Such sensors will allow the abovementioned locking sequence to be controlled automatically, or at least surely, thereby guaranteeing the precise positioning of the boom in the safety raised configuration and also guaranteeing any false maneuver likely to come out of the locking sequence. with harmful consequences for the boom, the spacer and the lifting cylinder.

Within the meaning of the invention, the third sensor detects that the stop is in abutment on the jack body to a ready tolerance of the order of 0.5 to 5 centimeters. In other words, the third sensor can detect that the stop is actually in abutment on the cylinder body (in this case the tolerance is zero), or that the stop is at a given distance (equivalent to the aforementioned tolerance) from the body of cylinder. Indeed, and as described later, this third sensor can be used to automatically stop a retraction of the movable rod, so that this tolerance will make it possible to take into consideration the latency between the detection made by the third sensor and the actual stop of the movable rod in its retraction movement. This tolerance will depend in particular on the speed of retraction of the movable rod during the locking phase described later.

• en présence de l'entretoise en position de libération, le premier capteur détecte la première cible ; et
• en absence de l'entretoise en position de libération, le premier capteur ne détecte pas la première cible.

According to one characteristic, the first sensor is associated with a first target, where one of the first sensor and of the first target is fixed on the arrow and where the other of the first sensor and of the first target is fixed on the spacer , so that :

• in the presence of the spacer in the release position, the first sensor detects the first target; and
• in the absence of the spacer in the release position, the first sensor does not detect the first target.

• lorsque l'entretoise est en position de libération, ce qui permet automatiquement de laisser la tige mobile libre d'être déplacée dans le corps de vérin pour agir sur le déplacement de la flèche relevable, notamment à vitesse élevée ;
• lorsque l'entretoise n'est plus en position de libération, ce qui permet de stopper automatiquement la tige mobile lors de la séquence de verrouillage jusqu'à ce que l'entretoise atteigne sa position de verrouillage.

This first sensor and this first target thus make it possible to detect:

• when the spacer is in the release position, which automatically allows the free movable rod to be moved in the cylinder body to act on the movement of the lifting boom, especially at high speed;
• when the spacer is no longer in the release position, which automatically stops the movable rod during the locking sequence until the spacer reaches its locking position.

According to a variant, the first sensor is a proximity sensor or presence sensor, such as for example an optical sensor, a mechanical sensor of the contactor type, a capacitive proximity sensor, an inductive proximity sensor, a Hall effect proximity sensor or an infrared proximity sensor.

• en présence de l'entretoise en position de verrouillage, le deuxième capteur détecte la tige mobile ; et
• en absence de l'entretoise en position de verrouillage, le deuxième capteur ne détecte pas la tige mobile.

According to another characteristic, the second sensor is fixed to the spacer or to the stop being turned in the direction of the movable rod, so that:

• in the presence of the spacer in the locked position, the second sensor detects the movable rod; and
• in the absence of the spacer in the locked position, the second sensor does not detect the movable rod.

This second sensor can be associated with a second target placed on the movable rod, and this second sensor makes it possible to detect when the spacer is in the locked position, which automatically makes it possible to retract the movable rod towards the deployed safety position, in particular at a reduced speed.

According to a variant, the second sensor is a proximity sensor or presence sensor, such as for example an optical sensor, a mechanical sensor of the contactor type, a capacitive proximity sensor, an inductive proximity sensor, a Hall effect proximity sensor. or an infrared proximity sensor.

• en présence de la butée en appui sur le corps de vérin, le troisième capteur détecte la troisième cible ; et
• en absence de la butée en appui sur le corps de vérin, le troisième capteur ne détecte pas la troisième cible.

According to another characteristic, the third sensor is associated with a third target, where one of the third sensor and of the third target is fixed on the cylinder body, and the other of the third sensor and of the third. target is mounted in cantilever on the stopper in order to extend beyond the stopper, so that:

• in the presence of the abutment bearing on the cylinder body, the third sensor detects the third target; and
• in the absence of the stop bearing on the cylinder body, the third sensor does not detect the third target.

This third sensor and this third target thus make it possible to detect when the stop is in abutment on the jack body, and therefore when the movable rod is in its deployed safety position, which makes it possible to automatically stop the movable rod and to know that the lockout sequence is complete.

According to a variant, the third sensor is a proximity sensor or presence sensor, such as for example an optical sensor, a mechanical sensor of the contactor type, a capacitive proximity sensor, an inductive proximity sensor, a Hall effect proximity sensor. or an infrared proximity sensor.

According to another variant, the other of the third sensor and of the third target is mounted on a support which is integral with the stop while projecting from the stop in a longitudinal direction of the spacer extending from the part proximal to the distal part. In other words, the support extends beyond the abutment surface (s) offered by the abutment, this or these abutment surface (s) abutting against the jack body at the end of the locking sequence.

In a particular embodiment, the stop is selectively adjustable in position on the spacer in a longitudinal direction extending from the proximal part to the distal part, with the stop which is slidably mounted on the distal part of the spacer and which cooperates with at least one locking member capable of fixedly locking the stop on the distal part in several adjustment positions.

Thus, with the same spacer and the same stop adjustable in position, it is possible to adapt the position of the stop according to the length of the boom, which guarantees a fixed reach of the boom on the ground whatever the boom length.

Indeed, having a fixed reach of the boom to the ground imposes different boom angles depending on the length of the boom. By adjusting the position of the stop on the spacer, it is possible to adjust the length of the movable rod in the deployed safety position and therefore to adjust the angle of the boom.

In a particular embodiment, one of the stop and the distal part of the spacer is provided with at least one first orifice and the other of the stop and the distal part of the spacer is provided with 'at least a series of several second orifices, and the locking member is a finger capable of engaging both in a first orifice and in a second orifice selected from the various second orifices providing several adjustment positions.

According to one possibility of the invention, the movable rod is pivotally mounted on the boom along a main pivot axis and the proximal part of the spacer is pivotally mounted on the boom along this same main pivot axis.

According to another possibility of the invention, the spacer comprises two longitudinal and parallel beams which respectively have proximal ends articulated on the arrow and distal ends between which the stop extends.

According to another advantageous characteristic of the invention, the stop has an arcuate shape suitable for partially surrounding the movable rod in the locking position of the spacer.

The present invention also relates to the characteristic that the locking device further comprises an actuator coupled to the spacer to control its movement between the locking position and the release position.

In a particular embodiment, the actuator comprises a locking winch equipped with a drum on which is wound a locking cable, which passes over at least one pulley disposed on the boom to the spacer.

Thus, the winding of the locking cable on the drum makes it possible to raise the spacer from the locking position to the release position, and the disengagement of the drum allows the unwinding of the locking cable allowing the spacer to be lowered under its own weight from the release position to the locked position.

Of course, other types of actuator can be envisaged, such as for example and without limitation, a linear actuator, a rotary motor coupled to the spacer by cable, belt, chain, link, etc. It is also conceivable to provide a motorized actuator or a manual actuator.

According to one possibility, at the end of the locking phase, the boom is locked in the raised safety configuration and is prohibited from moving both in the direction of a lowering by means of the locking device interposed between the body and the boom, and in the direction of a lifting by means of the lifting cylinder which retains the boom.

Alternatively, the crane is a luffing jib tower crane.

• dans une première phase ou phase de service, l'entretoise est en position de libération et la tige mobile est libre d'être déplacée dans le corps de vérin pour agir sur le déplacement de la flèche relevable ;
• dans une deuxième phase ou phase de transition, la tige mobile est déployée jusqu'à une position déployée de transition, au-delà de la position déployée de sécurité, et l'entretoise est déplacée jusqu'à sa position de verrouillage en étant rabattue sur la tige mobile ;
• dans une troisième phase ou phase de verrouillage, la tige mobile est rétractée de la position déployée de transition vers la position déployée de sécurité jusqu'à ce que la butée soit en appui sur le corps de vérin pour que l'entretoise maintienne fixement la tige mobile dans la position déployée de sécurité pour verrouiller la flèche relevable dans la configuration relevée de sécurité.

The invention also relates to a method for locking a lifting boom in a raised safety configuration, this method being implemented in a crane according to the invention by implementing the following locking sequence:

• in a first phase or service phase, the spacer is in the release position and the movable rod is free to be moved in the cylinder body to act on the movement of the lifting jib;
• in a second phase or transition phase, the movable rod is deployed to a deployed transition position, beyond the deployed safety position, and the spacer is moved to its locking position by being folded over the movable rod;
• in a third phase or locking phase, the movable rod is retracted from the deployed position of transition to the deployed security position until the stop is in abutment on the jack body so that the spacer fixes the rod securely movable in the deployed safety position to lock the lifting boom in the raised safety configuration.

• lorsque l'entretoise est en position de libération, la tige mobile est libre d'être déplacée dans le corps de vérin jusqu'à une vitesse maximale prédéfinie ;
• lorsque l'entretoise est en position de verrouillage et que la tige mobile est dans sa position déployée de transition, la tige mobile est rétractée vers la position déployée de sécurité à une vitesse réduite inférieure à la vitesse maximale.

In a particular realization:

• when the spacer is in the release position, the movable rod is free to be moved in the cylinder body up to a predefined maximum speed;
• when the spacer is in the locked position and the movable rod is in its deployed transitional position, the movable rod is retracted to the deployed safety position at a reduced speed lower than the maximum speed.

According to a variant, the spacer is detected in the release position by means of the first sensor described above.

According to another variant, the spacer is detected in the locked position by means of the second sensor described above.

• lorsque l'entretoise a quitté sa position de libération et n'a pas encore atteint sa position de verrouillage, la tige mobile est automatiquement interdite en déplacement ;
• lorsque l'entretoise a atteint sa position de verrouillage, la tige mobile est à nouveau et automatiquement libre en déplacement ;
• lorsque la butée vient en appui sur le corps de vérin, la tige mobile est automatiquement stoppée dans sa rétractation.

In a particular embodiment,

• when the spacer has left its release position and has not yet reached its locking position, the movable rod is automatically prohibited in movement;
• when the spacer has reached its locking position, the movable rod is again and automatically free to move;
• when the stop comes to bear on the cylinder body, the movable rod is automatically stopped in its retraction.

According to a variant, it is the first sensor which detects that the spacer has left its release position and it is the second sensor which detects that the spacer has not yet reached its locking position and that thereafter l spacer has reached its locking position.

According to another variant, it is the third sensor which detects that the stop is in abutment on the cylinder body and which makes it possible to automatically trigger the stopping of the movable rod in its retraction movement during the locking phase.

In a particular embodiment, once the locking device has locked the lifting boom in the raised safety configuration, there is provided a step of wind vane of the boom consisting of a disengagement of the boom so that it is free in rotation to automatically orient in the wind direction.

According to a variant, it is the third sensor which detects that the locking device has locked the lifting boom in the raised safety configuration.

Advantageously, once the locking device has locked the lifting boom in the raised safety configuration, there is provided, prior to the step of wind vane of the boom, a step of actuating an alarm signaling an authorization of boom vane.

According to a variant, the step of actuating the horn is automatically triggered as soon as the third sensor detects that the locking device has locked the lifting boom in the raised safety configuration.

• dans la phase de service, un premier capteur détecte l'entretoise en position de libération, autorisant automatiquement la tige mobile (31) à être déplacée dans le corps de vérin jusqu'à une vitesse maximale prédéfinie ;
• dans la phase de transition, le premier capteur détecte lorsque l'entretoise (5) a quitté sa position de libération, interdisant automatiquement la tige mobile en déplacement ;
• dans la phase de transition, un second capteur détecte lorsque l'entretoise (5) a atteint sa position de verrouillage, autorisant à nouveau et automatiquement la tige mobile à être libre en déplacement, éventuellement à une vitesse réduite ;
• dans la phase de verrouillage, un troisième capteur détecte lorsque la butée vient en appui sur le corps de vérin, stoppant automatiquement la tige mobile dans sa rétractation et, optionnellement, déclenchant automatiquement l'actionnement d'un avertisseur signalant une autorisation de mise en girouette de la flèche.

The invention also relates to the aforementioned method in which:

• in the service phase, a first sensor detects the spacer in the release position, automatically authorizing the movable rod (31) to be moved in the cylinder body up to a predefined maximum speed;
• in the transition phase, the first sensor detects when the spacer (5) has left its release position, automatically preventing the movable rod in movement;
• in the transition phase, a second sensor detects when the spacer (5) has reached its locking position, again and automatically allowing the movable rod to be free to move, possibly at a reduced speed;
• in the locking phase, a third sensor detects when the stop comes to rest on the cylinder body, automatically stopping the movable rod in its retraction and, optionally, automatically triggering the actuation of an alarm signaling a weather vane authorization of the arrow.

• la figure 1 est une vue schématique de côté et partielle d'une grue à flèche relevable conforme à l'invention, où le dispositif de verrouillage n'est pas visible pour une raison de taille ;
• la figure 2 est une vue schématique en perspective de dessus d'une portion proximale de la flèche de la grue de la figure 1, où le dispositif de verrouillage est visible ;
• la figure 3 est une vue schématique de côté de la portion proximale de la flèche illustrée en figure 2 ;
• la figure 4 est une vue schématique de côté et partielle d'une grue conforme à l'invention, où la flèche est relevée dans une configuration relevée de transition avec la tige mobile du vérin de relevage dans une position déployée de transition, et où l'entretoise est dans une position de libération ;
• la figure 5 est une vue schématique de côté et partielle de la grue de la figure 4, où l'entretoise est cette fois dans une position de verrouillage ;
• la figure 6 est une vue schématique de côté et partielle d'une grue conforme à l'invention, où la flèche est relevée dans une configuration relevée de transition avec la tige mobile du vérin de relevage dans une position déployée de transition, et où l'entretoise est illustrée à la fois dans une position de libération et dans une position de verrouillage (cette grue différant de celle des figures 4 et 5 dans le réglage de la position de la butée sur l'entretoise) ;
• la figure 7 est une vue schématique de côté et partielle de la grue de la figure 6, où la flèche est verrouillée dans une configuration relevée de sécurité avec la tige mobile du vérin de relevage bloquée au moyen de l'entretoise dans une position déployée de sécurité (la tige mobile ayant été rétractée comparativement à la figure 6) ;
• la figure 8 est une vue schématique partielle et en perspective de l'entretoise en position de verrouillage, avec la butée en appui sur le corps de vérin du vérin de levage ;
• la figure 9 est une vue schématique partielle et en perspective de l'entretoise illustrant les moyens de réglage en position de la butée coulissante ;
• la figure 10 est une vue schématique partielle et en perspective de l'entretoise et de sa butée, montrant les plaques de butée de la butée ;
• la figure 11 est une vue schématique partielle et de côté de l'entretoise dans une position de libération ;
• la figure 12 est une vue schématique partielle et de côté de l'entretoise dans une position de verrouillage avec la tige mobile dans une position déployée de transition ;
• la figure 13 est une vue schématique partielle et de côté de l'entretoise dans une position de verrouillage avec la tige mobile bloquée au moyen de l'entretoise dans une position déployée de sécurité (la tige mobile ayant été rétractée comparativement à la figure 12) ;
• les figures 14 et 15 sont des vues schématiques de dessus d'une entretoise, respectivement sans la butée et avec la butée.

Other characteristics and advantages of the present invention will appear on reading the detailed description below, of an example of non-limiting implementation, made with reference to the appended figures in which:

• the figure 1 is a schematic side and partial view of a lifting jib crane according to the invention, where the locking device is not visible for a size reason;
• the figure 2 is a schematic perspective view from above of a proximal portion of the boom of the crane of the figure 1 , where the locking device is visible;
• the figure 3 is a schematic side view of the proximal portion of the arrow illustrated in figure 2 ;
• the figure 4 is a schematic side and partial view of a crane according to the invention, where the boom is raised in a raised transition configuration with the movable rod of the lifting cylinder in a deployed transition position, and where the spacer is in a release position;
• the figure 5 is a schematic side and partial view of the crane of the figure 4 , where the spacer is this time in a locked position;
• the figure 6 is a schematic side and partial view of a crane according to the invention, where the boom is raised in a raised transition configuration with the movable rod of the lifting cylinder in a deployed transition position, and where the spacer is illustrated both in a release position and in a locked position (this crane differing from that of figures 4 and 5 in adjusting the position of the stop on the spacer);
• the figure 7 is a schematic side and partial view of the crane of the figure 6 , where the boom is locked in a raised safety configuration with the movable rod of the lifting cylinder locked by means of the spacer in a deployed safety position (the movable rod having been retracted compared to the figure 6 );
• the figure 8 is a partial schematic perspective view of the spacer in the locked position, with the stop bearing on the cylinder body of the lifting cylinder;
• the figure 9 is a partial schematic perspective view of the spacer illustrating the means for adjusting the position of the sliding stop;
• the figure 10 is a partial schematic perspective view of the spacer and its stop, showing the stop plates of the stop;
• the figure 11 is a partial schematic side view of the spacer in a release position;
• the figure 12 is a partial schematic side view of the spacer in a locking position with the movable rod in a deployed transitional position;
• the figure 13 is a partial schematic side view of the spacer in a locked position with the movable rod locked by means of the spacer in a deployed safety position (the movable rod having been retracted compared to the figure 12 );
• the Figures 14 and 15 are schematic top views of a spacer, respectively without the stopper and with the stopper.

Crane 1 has lifting boom, shown on figure 1 , here is a tower crane which comprises a vertical mast 10 anchored or mobile on the ground, surmounted, by means of an orientation device, of a part rotating 11 mainly comprising a rotating pivot 12, a counter-jib 13 on which is mounted a counterweight 14, and a jib 2 which can be raised.

The rotary pivot 12 can be oriented around the vertical axis of the mast 10 and it supports a driver's cabin 15 of the crane 1.

The counter-jib 13 extends substantially horizontally rearward, from the rotary pivot 12, and it carries in particular a lifting winch 16 for lifting the loads suspended on the jib 2, as well as the counterweight 14. This counter arrow 13 is suspended by means of tie rods 19.

The lifting winch 16 has a drum on which a lifting cable 17 is wound, which passes over pulleys, then is directed towards the point 21 of the arrow 2 and extends to a lifting hook 18, with or without reeving, the loads to be lifted are suspended from the hook 18 when using the crane 1.

The lifting jib 2 is formed by a lattice structure, for example of triangular section, and it has a proximal portion 20 articulated, around a pivot axis 22 horizontal, on the rotary pivot 12. This proximal portion 20 forms the foot arrow 2.

The proximal portion 20 has upper beams 23 and lower beams 24 interconnected by members and by a lower cross member 25 located at the end (that is to say opposite the pivot axis 22) and in the lower part of the proximal portion 20. In the lowered configuration of the arrow 2 visible on the figures 1 and 3 , when the arrow 2 is horizontal, the upper beams 23 extend substantially horizontally, while the lower beams 24 extend obliquely relative to the horizontal.

The crane 1 further comprises a lifting cylinder 3 which may be of the hydraulic linear cylinder or electric linear cylinder type. This lifting cylinder 3 can act on the proximal portion 20 of the boom 2 to move the boom 2 between at least one lowered position (as visible on the figures 1 and 3 ) and at least one raised position (as visible on the figures 4 to 7 ). The lifting cylinder 3 comprises a cylinder body 30 and a movable rod 31.

• une extrémité arrière 33 supportant une articulation, telle qu'une rotule d'articulation, qui relie mécaniquement le corps de vérin 30 au pivot tournant 12 ; et
• une extrémité avant 34 ouverte et à travers laquelle débouche la tige mobile 31, où cette extrémité avant 34 définit une surface d'appui 340 annulaire qui est orthogonale à la tige mobile 31.

The cylinder body 30 is mechanically connected to the rotary pivot 12 by a pivot connection around a horizontal pivot axis 32. As such, the cylinder body 30 has:

• a rear end 33 supporting a hinge, such as a hinge ball, which mechanically connects the cylinder body 30 to the rotary pivot 12; and
• a front end 34 open and through which the movable rod 31 opens, where this front end 34 defines an annular bearing surface 340 which is orthogonal to the movable rod 31.

The jack body 30 may comprise, at this front end 34, a support device which defines this support surface 340.

The movable rod 31 is mechanically connected to the proximal portion 20 of the boom 2 by a pivot connection around a horizontal main pivot axis 35, so that this proximal portion 20 is movable between the lowered position and the raised position. When the crane 1 is in service, the lifting cylinder 3 makes it possible to raise or lower the jib 2, via the proximal portion 20. The movable rod 31 has a front end 36 supporting a hinge, such as an articulation ball, which mechanically connects the movable rod 31 to the proximal portion 20.

The lifting cylinder 3 is a linear cylinder configured so that the movable rod 31 is movable in the cylinder body 30 between at least one deployed position (as visible on the figures 4 to 7 ) and at least one retracted position (as visible on the figures 1 and 3 ) to move the boom 2 up and down between at least one raised configuration (as visible on the figures 4 to 7 ) and at least one lowered configuration (as visible on the figures 1 and 3 ).

The crane 1 further comprises a supply device 37 which is configured to supply energy to the lifting cylinder 3 so as to raise the boom 2. In the case of a hydraulic lifting cylinder 3, the supply device 37 is a hydraulic unit configured to supply the lifting cylinder 3 with hydraulic energy. When it is supplied with energy, the lifting cylinder 3 can raise the jib 2. The supply device 37 is fixed to the counter-jib 13 and it is located relatively close to the lifting cylinder 3, opposite the counterweight 14.

The lifting cylinder 3 extends in a vertical median plane of the arrow 2, so that the articulation of the movable rod 31 on the proximal portion 20 of the arrow 2 is located in a vertical median plane of the proximal portion 20 More specifically, the movable rod 31 is articulated on the lower cross member 25, and more precisely in the middle of this lower cross member 25.

The crane 1 further comprises a locking device 4 capable of cooperating with the lifting cylinder 3 to mechanically lock the movable rod 31 of the lifting cylinder 3 in a deployed safety position (visible on the figure 7 ) and thus block the boom 2 in a raised safety configuration.

• une position de libération (visible sur les figures 2 à 4 et 6) dans laquelle l'entretoise 5 est déportée vis-à-vis du vérin de relevage 3 en étant rabattue en direction de la portion proximale 20 ; et
• une position de verrouillage (visible sur les figures 5 à 7) dans laquelle l'entretoise 5 est rabattue sur le vérin de relevage 3, et plus précisément sur la tige mobile 31.

This locking device 4 comprises a spacer 5 (visible only on the figure 14 ) on which is mounted a stop 6, where the spacer 5 is pivotally movable on the proximal portion 20 of the arrow 2 between:

• a release position (visible on the figures 2 to 4 and 6 ) in which the spacer 5 is offset vis-à-vis the lifting cylinder 3 by being folded towards the proximal portion 20; and
• a locking position (visible on the Figures 5 to 7 ) in which the spacer 5 is folded down on the lifting cylinder 3, and more precisely on the movable rod 31.

Starting from the release position towards the locking position, the stop 6 follows an arc which brings it closer to the movable rod 31 until it comes to bear on the movable rod 31. Conversely, starting from the locking position towards the release position, the stop 6 follows an arc which moves it away from the movable rod 31 and brings it closer to the proximal portion 20 of the arrow 2.

• des extrémités proximales 51 articulées sur la portion proximale 20 de la flèche 2 ; et
• des extrémités distales 52 entre lesquelles s'étend la butée 6.

The spacer 5 comprises two longitudinal beams 50 which are parallel and which respectively have:

• proximal ends 51 articulated on the proximal portion 20 of the arrow 2; and
• distal ends 52 between which extends the stop 6.

Thus, the spacer 5 comprises a proximal part 510 composed of the proximal ends 51 of the two longitudinal beams 50, where this proximal part 510 is mechanically connected to the proximal portion 20 of the arrow 2 by a pivot connection around the pivot axis main 35 which, as a reminder, corresponds to the pivot axis of the movable rod 31 on the proximal portion 20 of the arrow 2. In other words, the pivot axis of the spacer 5 on the proximal portion 20 and the pivot axis of the movable rod 31 on the proximal portion 20 are combined.

In addition, the spacer 5 comprises a distal part 520 composed of the distal ends 52 of the two longitudinal beams 50, where this distal part 520 supports the stop 6.

The two longitudinal beams 50 have sufficient spacing to be able to extend on either side of the movable rod 31 in the locked position.

In the release position, the two longitudinal beams 50 extend obliquely relative to the movable rod 31, and extend in particular parallel to the lower beams 24 of the proximal portion 20 of the arrow 2.

In the locked position, the two longitudinal beams 50 extend parallel to the movable rod 31.

The spacer 5 also comprises crosspieces 53 of arcuate shape, or more precisely of arch shape, so that the crosspieces 53 can match the movable rod 31. These crosspieces 53 are positioned in the central part of the longitudinal beams 50 and connect the two longitudinal beams 50 together. In the example illustrated, the crosspieces 53 are integral with the same central part 530 extending fixedly between the two longitudinal beams 50.

The stop 6 is mounted on the distal ends 52 of the two longitudinal beams 50, extending transversely between the two longitudinal beams 50. This stop 5 has an arcuate shape, or more precisely an arch shape, so that the stop 6 can match the movable rod 31.

• deux coulisses 60 montées coulissantes sur les extrémités distales 52 des poutres longitudinales 50 respectives ; et
• une partie centrale 61 arquée s'étendant entre les deux coulisses 60 et définissant une gorge 63 à l'intérieur de laquelle se positionne la tige mobile 31 en position de verrouillage ;
• deux plaques de butée 64 fixées sur la partie centrale 61, de part et d'autre de la gorge 63, où ces plaques de butée 64 sont tournées en direction de la surface d'appui 340 annulaire de l'extrémité avant 34 du corps de vérin 31 en position de verrouillage.

Stop 6 includes:

• two slides 60 slidably mounted on the distal ends 52 of the respective longitudinal beams 50; and
• a central arcuate part 61 extending between the two slides 60 and defining a groove 63 inside which the movable rod 31 is positioned in the locked position;
• two stop plates 64 fixed on the central part 61, on either side of the groove 63, where these stop plates 64 are turned in the direction of the annular bearing surface 340 of the front end 34 of the body cylinder 31 in the locked position.

These abutment plates 64 thus define two abutment surfaces capable of abutting against the bearing surface 340, in order to lock the arrow 2 in the raised safety configuration.

Each slide 60 is provided with a first orifice 65 passing right through, and each longitudinal beam 50 is provided, at its distal end 52, with a series of several second orifices 55 passing right through. Thus, the stop 6 is selectively adjustable in position on the spacer in a longitudinal direction 59 parallel to the longitudinal beams 50, by using locking members in the form of two locking fingers 7 which engage both in a first orifice 65 and in a second orifice 55 selected from the various second orifices 55 providing several adjustment positions.

Each locking finger 7 can be locked by means of locking elements 70, such as for example a nut, a pin (as illustrated in the figure 9 ), a socket, a circlip, or any other means providing a blocking or locking of the locking finger 7 on the corresponding slide.

Thus, depending on the positioning of the locking fingers 7 in the second orifices 55, the stop 6 is more or less close to the proximal part 510 of the spacer 5 and to the main pivot axis 35. As an illustrative example , the stop 6 is less close - or more distant - from the proximal ends 51 of the longitudinal beams 50 in the production of figures 4 and 5 compared to the achievement of figures 6 and 7 .

This adjustment of the position of the stopper 6 on the spacer 5 will make it possible to adjust the length of the movable rod 31 in the deployed safety position (subsequently described) and consequently adjust the angle of the arrow 2 in the raised configuration safety, which allows an adjustment of the reach of the boom 2 on the ground in this raised safety configuration.

The locking device 4 further comprises an actuator which consists of a locking winch 9 (visible on the figures 2 and 3 ) equipped with a drum 90 on which a locking cable 91 is wound, which passes over pulleys and guides 92 arranged on the proximal portion 20 of the arrow 2 up to the spacer 5.

The spacer 5 comprises an anchoring element 56 on which is fixed one end of the locking cable 91. This anchoring element 56 is integral with one of the crosspieces 53, and in particular of the most transverse 53 remote from the proximal ends 51 of the longitudinal beams 50 to reduce the effort required to raise the spacer 5.

This locking winch 9 is fixedly mounted on the proximal portion 20 of the arrow 2 and the rotation of the drum 90 is carried out either manually by means of a crank 93 (as visible in the example of figures 2 and 3 ) or by means of a motor in a preferred example not illustrated.

• de la position de verrouillage vers la position de libération, en faisant tourner le tambour 90 dans le sens d'un enroulement du câble de verrouillage 91, ce qui permet de relever l'entretoise 5 en tirant dessus ;
• de la position de libération vers la position de verrouillage, en débrayant le tambour 90 pour libérer le tambour 90 dans le sens d'un déroulement du câble de verrouillage 91, ce qui permet à l'entretoise 5 de s'abaisser sous son propre poids.

With this locking winch 9, the spacer 5 is moved as follows:

• from the locking position to the release position, by rotating the drum 90 in the direction of winding the locking cable 91, which makes it possible to raise the spacer 5 by pulling on it;
• from the release position to the locking position, by disengaging the drum 90 to release the drum 90 in the direction of unwinding of the locking cable 91, which allows the spacer 5 to lower under its own weight .

The locking device 4 thus allows the implementation of a locking sequence which results in locking of the liftable jib 2 in the raised safety configuration (visible in figure 7 ). This locking sequence is carried out in three successive phases.

A first phase corresponds to a service phase where the spacer 5 is in the release position (visible on the figures 2 to 4 , 6 and 11 ) so that the movable rod 31 is free to be moved in the cylinder body 30 to act on the movement of the jib 2 which can be raised, whether it is in lowering or in raising. In this service phase, the movable rod 31 is free to be moved in the cylinder body 30 up to a predefined maximum speed. Thus, the movable rod 31 can be moved at the maximum authorized speed. In this service phase, the crane 1 is in service and is used for the distribution of loads.

A second phase corresponds to a transition phase where, starting from the service phase, the movable rod 31 is deployed to a deployed transition position (visible on the figures 4 to 6 ). This transitional deployed position is located beyond the deployed safety position (described below) and is close to a maximum deployed position, or even corresponds to a maximum deployed position (i.e. with the movable rod 31 at its maximum length exiting the cylinder body 30). At the end of this deployment of the movable rod 31 in the deployed transition position, the boom 2 is raised to a raised transition configuration, which is more raised than the deployed safety position.

In this transition phase, and following the deployment of the movable rod 31 in the deployed transition position, the spacer 5 is moved from its release position to its locking position (visible on the figures 5, 6 and 12 ) by being folded down on the movable rod 31.

A third phase corresponds to a locking phase where, following the transition phase, the movable rod 31 is retracted from the deployed transition position (visible on the figures 4 to 6 and 12 ) to the deployed safety position (visible on the figures 7, 8 and 13 ) until the stop 6 is supported on the cylinder body 30 so that the spacer 5 fixes the movable rod 31 securely in the deployed safety position, which results in locking the boom 2 in the configuration security clearance.

In this locking phase, the movable rod 31 is retracted to the deployed safety position at a reduced speed lower than the maximum speed, then is stopped in its retraction movement.

At the end of the locking phase, the stop 6 is therefore in abutment on the jack body 30, and more precisely the two abutment plates 64 are in abutment on the annular bearing surface 340 of the front end 34 cylinder body 31.

Once the locking device 6 has locked the boom 2 in the raised safety configuration, in other words at the end of the locking phase, there is provided a step for wind vane of the boom 2 consisting of a disengagement of the arrow 2 (by unlocking the orientation brakes provided at the rotating pivot 12) so that the arrow 2 is free to rotate along a vertical axis to automatically orient itself in the direction of the wind.

• dans le sens d'un abaissement au moyen du dispositif de verrouillage 4 qui est intercalé entre le corps de butée 30 (avec l'appui de la butée 6) et la flèche 2 (avec l'entretoise 5 articulée sur la flèche 2), notamment en cas de de dilatation ou de fuite d'huile avec un vérin de relevage 3 hydraulique ; et
• dans le sens d'un relevage au moyen du vérin de relevage 3 qui retient la flèche 2 en l'empêchant de monter, notamment en cas de vent tourbillonant qui pousse la flèche 2 par-dessous.

In addition, at the end of the locking phase, the arrow 2 is prohibited from moving in both directions, namely:

• in the direction of a lowering by means of the locking device 4 which is interposed between the stop body 30 (with the support of the stop 6) and the arrow 2 (with the spacer 5 articulated on the arrow 2), especially in the event of expansion or oil leakage with a hydraulic lifting cylinder 3; and
• in the direction of a lifting by means of the lifting cylinder 3 which retains the boom 2 by preventing it from going up, in particular in the event of a whirlwind which pushes the boom 2 from below.

This prohibition is advantageous in the case of a lack of activity and human surveillance, the crane 1 being able to remain in security without surveillance.

The locking device 4 also comprises three sensors 81, 82, 83 which will make it possible to control the locking sequence described above in a reliable, secure and precise manner.

A first sensor 81 is used to detect the presence / absence of the spacer 5 in the release position. This first sensor 81 is fixed on the proximal portion 20 of the arrow 2 and it takes the form of a proximity sensor (or presence sensor).

• en présence de l'entretoise 5 en position de libération, le premier capteur 81 détecte la première cible 57 ; et
• en absence de l'entretoise 5 en position de libération, le premier capteur 81 ne détecte pas la première cible.

This first sensor 81 is associated with a first target 57 integral with the spacer 5. This first target 57 is in the form of a plate projecting from one of the crosspieces 53 in a plane orthogonal to the longitudinal direction 59. When the spacer 5 is in the release position, the plate or first target 57 is located directly opposite the first sensor 81, at a predefined distance less than the range of the first sensor 81, so that:

• in the presence of the spacer 5 in the release position, the first sensor 81 detects the first target 57; and
• in the absence of the spacer 5 in the release position, the first sensor 81 does not detect the first target.

• une face avant sur laquelle est fixé l'élément d'ancrage 56, et
• une face arrière prévue pour être en regard du premier capteur 81 lorsque l'entretoise 5 est en position de libération

In the example illustrated, this plate 57 has:

• a front face on which the anchoring element 56 is fixed, and
• a rear face intended to be opposite the first sensor 81 when the spacer 5 is in the release position

In a variant not illustrated, the first sensor 81 is fixed on the spacer 5 while the first target is fixed on the proximal portion 20 of the arrow 2 (reverse configuration compared to that illustrated).

A second sensor 82 is used to detect the presence / absence of the spacer 5 in the locked position. This second sensor 82 is fixed on the stop 6 and it takes the form of a proximity sensor (or presence sensor).

• en présence de l'entretoise 5 en position de verrouillage, le deuxième capteur 82 se situe directement en face de la tige mobile 31, à une distance prédéfinie inférieure à la portée du deuxième capteur 82, et ainsi le deuxième capteur 82 détecte la tige mobile 31 ; et
• en absence de l'entretoise 5 en position de verrouillage, le deuxième capteur 82 est éloigné de la tige mobile 31 et ne détecte donc pas la tige mobile 31.

This second sensor 82 is turned in the direction of the movable rod 31, so that:

• in the presence of the spacer 5 in the locked position, the second sensor 82 is located directly opposite the movable rod 31, at a predefined distance less than the range of the second sensor 82, and thus the second sensor 82 detects the movable rod 31; and
• in the absence of the spacer 5 in the locked position, the second sensor 82 is distant from the movable rod 31 and therefore does not detect the movable rod 31.

This second sensor 82 is fixed on a plate 66 projecting from the central part 61 of the stop 6, at the rear of the latter (that is to say opposite the stop plates 64 and the body of cylinder 30). Thus, this second sensor 82 is mounted cantilevered on the stop 6 so as to extend behind the stop 6.

In a variant not illustrated, the second sensor 82 is fixed on the spacer 5, and in particular on one of the crosspieces 53.

A third sensor 83 is used to detect the presence of the stop 6 bearing on the cylinder body 30, with possibly a tolerance to take into account the latency between the detection made by this third sensor 83 and the stop of its retraction movement. in the locking phase. This third sensor 83 is fixed to the stop 6 and is in the form of a proximity sensor (or presence sensor).

This third sensor 83 is fixed on a plate 67 projecting from the central part 61 of the stop 6, at the front of the latter (that is to say on the same side as the stop plates 64 and therefore opposite cylinder body 30). Thus, this third sensor 83 is mounted in cantilever on the stop 6 so as to extend in front of the stop 6, and even beyond the stop 6 in the direction where this third sensor 83 s 'extends overhanging beyond the stop plates 64 in the longitudinal direction 59.

• en présence de la butée 6 en appui sur le corps de vérin 30 (comme visible sur la figure 13), c'est-à-dire dans le cas où la butée 6 se situe à une distance inférieure ou égale à la tolérance précitée vis-à-vis du corps de vérin 30, le troisième capteur 83 se situe directement en face du corps de vérin 30 (qui forme une troisième cible), à une distance prédéfinie inférieure à la portée du troisième capteur 83, et ainsi ce troisième capteur 83 détecte le corps de vérin 30 ; et
• en absence de la butée 6 en appui sur le corps de vérin 30, c'est-à-dire dans le cas où la butée 6 se situe à une distance supérieure à la tolérance précitée vis-à-vis du corps de vérin 30, le troisième capteur 83 est éloigné du corps de vérin 30 et ne détecte donc pas le corps de vérin 30.

This third sensor 83 is turned in the direction of the movable rod 31 and of the jack body 30 so that:

• in the presence of the stop 6 bearing on the cylinder body 30 (as visible on the figure 13 ), that is to say in the case where the stop 6 is located at a distance less than or equal to the above tolerance with respect to the cylinder body 30, the third sensor 83 is located directly in front of the body cylinder 30 (which forms a third target), at a predefined distance less than the range of the third sensor 83, and thus this third sensor 83 detects the cylinder body 30; and
• in the absence of the stop 6 bearing on the jack body 30, that is to say in the case where the stop 6 is located at a distance greater than the above-mentioned tolerance with respect to the jack body 30, the third sensor 83 is distant from the cylinder body 30 and therefore does not detect the cylinder body 30.

In the transition phase, and as visible on the figure 12 , the third sensor 83 is located directly opposite the movable rod 31. However, this third sensor 83 is offset upwards compared to the second sensor 82 so that, in this transition phase, the second sensor 82 is close enough to the movable rod 31 for detecting the movable rod 31, while the third sensor 83 is too far from the movable rod 31 to detect it, this in order to avoid false detection by the third sensor 83.

On the other hand, in the locking phase, and as visible on the figure 13 , this third sensor 83 is located directly opposite the cylinder body 30 while being close enough to the cylinder body 30 to detect it.

During the locking sequence described above, these three sensors 81, 82, 83 are used as follows.

The first sensor 81 is used during the service phase to confirm the presence of the spacer 5 in the release position, and thus allow the movable rod 31 to move in the cylinder body 30 to act on the movement of the boom 2.

This first sensor 81 is also used during the transition phase, when the spacer 5 has left its release position and has not yet reached its locking position, to prevent movement of the movable rod 31 and thus maintain it automatically in its deployed transitional position. In other words, once the first sensor 81 has detected the absence of the spacer 5 in the release position, and as long as the second sensor 82 has not yet detected the presence of the spacer 5 in the locking position, then the movable rod 31 is frozen in its deployed transitional position.

Then, and still in the transition phase, the second sensor 82 detects the presence of the spacer 5 in the locking position, which allows the retraction of the movable rod 31 for the following locking phase.

Finally, during the locking phase, the third sensor 83 detects that the stop 6 is in contact with the jack body 30, which makes it possible to automatically stop the movable rod 31 in its retraction. This detection by the third sensor 83 can also be used to automatically activate an alarm (light, visual, audible) indicating the authorization for the vane of arrow 2.

As long as the third sensor 83 detects that the stop 6 is in contact with the jack body 30, the retraction of the movable rod 31 is prohibited, but the deployment of the movable rod 31 is authorized (preferably at reduced speed) to return to the deployed transitional position, and then to raise the spacer 5 and put the crane 1 back into a service phase.

Claims (20)

1. A crane (1) comprising a luffing boom (2) and a lifting cylinder (3), said lifting cylinder (3) comprising a cylinder body (30) mechanically connected to a structural element (12) of the crane (1) and a movable rod (31) hinged on the luffing boom (2), wherein the movable rod (31) is displaceable in the cylinder body (30) between at least one deployed position and at least one retracted position in order to raise and lower the luffing boom (2) between at least one raised configuration and at least one lowered configuration, said crane (1) being characterized in that it further comprises a locking device (4) adapted to cooperate with said lifting cylinder (3) to mechanically lock the movable rod (31) in a deployed safety position and thus block the luffing boom (2) in a raised safety configuration, wherein said locking device (4) comprises a spacer (5) provided with a proximal portion (510) hinged on the boom (2) and with a distal portion (520) supporting an abutment (6), wherein said spacer (5) is pivotally movable on the boom (2) between:

   - a release position wherein the spacer (5) is offset vis-a-vis the lifting cylinder (3) such that its distal portion (520) is spaced apart from the lifting cylinder (3), authorizing the movable rod (31) to be displaced in the cylinder body (30) and to act on the displacement of the luffing boom (2); and

   - a locking position wherein the spacer (5) is folded over the lifting cylinder (3) such that the abutment (6) is able to bear on the cylinder body (30);

   wherein a locking of the luffing boom (2) in the raised safety configuration can be carried out according to the following locking sequence:

   - in a first phase or operating phase, the spacer (5) is in the release position and the movable rod (31) is free to be displaced in the cylinder body (30) to act on the displacement of the luffing boom (2);

   - in a second phase or transitional phase, the movable rod (31) is deployed to a deployed transition position, beyond the deployed safety position, and the spacer (5) is displaced to its locking position by being folded over the movable rod (31);

   - in a third phase or locking phase, the movable rod (31) is retracted from the deployed transition position towards the deployed safety position until the abutment (6) bears on the cylinder body (30) so that the spacer (5) fixedly maintains the movable rod (31) in the deployed safety position in order to lock the luffing boom (2) in the raised safety configuration.
2. The crane (1) according to claim 1, wherein the locking device (4) further comprises:

   - a first sensor (81) detecting the presence of the spacer (5) in the release position;

   - a second sensor (82) detecting the presence of the spacer (5) in the locking position;

   - a third sensor (83) detecting the presence of the abutment (6) bearing on the cylinder body (30).
3. The crane (1) according to claim 2, wherein the first sensor (81) is associated with a first target, wherein one of the first sensor (81) and of the first target is fixed on the boom (2) and wherein the other of the first sensor (81) and of the first target is fixed on the spacer (5), such that:

   - in the presence of the spacer (5) in the release position, the first sensor (81) detects the first target; and

   - in the absence of the spacer (5) in the release position, the first sensor (81) does not detect the first target.
4. The crane (1) according to any one of claims 2 and 3, wherein the second sensor (82) is fixed on the spacer (5) or on the abutment (6) being turned in the direction of the movable rod (31), such that:

   - in the presence of the spacer (5) in the locking position, the second sensor (82) detects the movable rod (31); and

   - in the absence of the spacer (5) in the locking position, the second sensor (82) does not detect the movable rod (31).
5. The crane (1) according to any one of claims 2 to 4, wherein the third sensor (83) is associated with a third target, wherein one of the third sensor (83) and of the third target is fixed on the cylinder body (30), and the other of the third sensor (83) and of the third target is cantilever-mounted on the abutment (6) in order to extend beyond the abutment (6), such that:

   - in the presence of the abutment (6) bearing on the cylinder body (30), the third sensor (83) detects the third target; and

   - in the absence of the abutment (6) bearing on the cylinder body (30), the third sensor (83) does not detect the third target.
6. The crane (1) according to any one of the preceding claims, wherein the abutment (6) is selectively position-adjustable on the spacer (5) in a longitudinal direction (59) extending from the proximal portion (510) to the distal portion (520), with the abutment (6) slidably mounted on the distal portion (520) of the spacer (5) and cooperating with at least one locking member (7) adapted to fixedly lock the abutment (6) on the distal portion (520) in several adjustment positions.
7. The crane (1) according to claim 6, wherein one of the abutment (6) and of the distal portion (520) of the spacer (5) is provided with at least a first orifice (65) and the other of the abutment (6) and of the distal portion (520) of the spacer (5) is provided with at least a series of several second orifices (55), and the locking member is a locking finger (7) adapted to engage both in a first orifice (65) and in a second orifice (55) selected from the different second orifices (55) providing several adjustment positions.
8. The crane (1) according to any one of the preceding claims, wherein the movable rod (31) is pivotally mounted on the boom (2) along a main pivot axis (35) and the proximal portion (510) of the spacer (5) is pivotally mounted on the boom (2) along this same main pivot axis (35).
9. The crane (1) according to any one of the preceding claims, wherein the spacer (5) comprises two longitudinal (50) and parallel beams that respectively have proximal ends (51) hinged on the boom (2) and distal ends (52) between which the abutment (6) extends.
10. The crane (1) according to any one of the preceding claims, wherein the abutment (6) has an arcuate shape adapted to partially surround the movable rod (31) in the locking position of the spacer (5).
11. The crane (1) according to any one of the preceding claims, wherein the locking device (4) further comprises an actuator (9) coupled to the spacer (5) for driving its displacement at least between the locking position and the release position.
12. The crane (1) according to claim 11, wherein the actuator is a locking winch (9) equipped with a drum (90) on which is wound a locking cable (91) that passes over at least one pulley (92) disposed on the boom (2) to the spacer (5).
13. The crane (1) according to any one of the preceding claims, wherein, as a result of the locking phase, the boom (2) is locked in the raised safety configuration and is prohibited from moving both in the direction of a lowering by means of the locking device (4) interposed between the abutment body (30) and the boom (2), and in the direction of a raising by means of the lifting cylinder (3) that holds the boom (2).
14. The crane (1) according to any one of the preceding claims, wherein the crane (1) is a tower crane (1).
15. A method for locking a luffing boom (2) in a raised safety configuration, said method being characterized in that it implements in a crane (1) in accordance with any one of the preceding claims by implementing the following locking sequence:

    - in a first phase or operating phase, the spacer (5) is in the release position and the movable rod (31) is free to be displaced in the cylinder body (30) to act on the displacement of the luffing boom (2);

    - in a second phase or transitional phase, the movable rod (31) is deployed to a deployed transition position, beyond the deployed safety position, and the spacer (5) is displaced to its locking position by being folded over the movable rod (31);

    - in a third phase or locking phase, the movable rod (31) is retracted from the deployed transition position towards the deployed safety position until the abutment (6) bears on the cylinder body (30) so that the spacer (5) fixedly maintains the movable rod (31) in the deployed safety position in order to lock the luffing boom (2) in the raised safety configuration.
16. The method according to claim 15, wherein:

    - when the spacer (5) is in the release position, the movable rod (31) is free to be displaced in the cylinder body (30) up to a predefined maximum speed;

    - when the spacer (5) is in the locking position and the movable rod (31) is in its deployed transition position, the movable rod (31) is retracted towards the deployed safety position at a reduced speed smaller than the maximum speed.
17. The method according to any one of claims 15 and 16, wherein:

    - when the spacer (5) has left its release position and has not yet reached its locking position, the movable rod (31) is automatically prohibited in displacement;

    - when the spacer (5) has reached its locking position, the movable rod (31) is again and automatically free in displacement;

    - when the abutment (6) bears on the cylinder body (30), the movable rod (31) is automatically stopped in its retraction.
18. The method according to any one of claims 15 to 17, wherein, once the locking device (4) has locked the luffing boom (2) in the raised safety configuration, there is provided a step of weathervaning the boom (2) consisting of a disengagement of the boom (2) so that it is free in rotation to be automatically oriented in the direction of the wind.
19. The method according to claim 18, wherein, once the locking device (4) has locked the luffing boom (2) in the raised safety configuration, there is provided, prior to the step of weathervaning the boom (2), a step of actuating an alarm signaling an authorization of weathervaning the boom (2).
20. The method according to any one of claims 15 to 19, wherein:

    - in the operating phase, a first sensor detects the spacer in the release position, automatically authorizing the movable rod (31) to be displaced in the cylinder body (30) up to a predefined maximum speed;

    - in the transitional phase, the first sensor detects when the spacer (5) has left its release position, automatically prohibiting the movable rod (31) in displacement;

    - in the transitional phase, a second sensor detects when the spacer (5) has reached its locking position, authorizing again and automatically the movable rod (31) to be free in displacement;

    - in the locking phase, a third sensor detects when the abutment (6) bears on the cylinder body (30), automatically stopping the movable rod (31) in its retraction.

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