EP1667931B1 - Lifting device - Google Patents

Abstract

The machinery has counter-weights (100) moving in a curvilinear guiding path (1) arranged opposite a boom. Slope variation of the path is chosen such that the counter-weights exert a variable traction on the boom through a hold back (11). The traction assists deployment/folding movement of the boom in articulated or inclinable working mode and/or change of conformation of the boom associated to a change of working mode.

Description

The present invention relates to a steerable and articulated steerable load lifting and handling machine, comprising a pylon with a rotating pivot, an articulated boom comprising an articulating boom, articulated at its first end to the top of the pylon by a spindle horizontal rotation, a dart hinged in rotation by a horizontal hinge pin at the second end of the boom foot, an arrow retainer assembly comprising at least one punch, an arrow holding sling, and a movable counterweight connected to the boom by said restraining sling

To enable the handling of loads on construction sites, it is customary to use horizontal directional distributor jib cranes, on which slides a carriage serving as a guide to means for suspending the loads.

In certain circumstances, for example when the construction sites are congested or when the legislation forbids the overflight of parcels adjoining the building site, they are preferred cranes with distributable arrow luffing and orientable. Lifting distributing boom cranes have the advantage over horizontal boom cranes of being able to bring loads to higher heights at comparable tower heights. The dead weight effort of an arrow operating in the liftable working mode varies considerably between the positions of the arrow near the horizontal and the raised position close to the vertical. That is why this type of crane is sometimes equipped with a mobile counterweight, the position of which varies according to the angle that the arrow makes with the horizontal.

The document DE 3438937 describes a luffing jib crane, with a platform at the top of the tower, carrying a counterweight disposed at one end of an oscillating arm. The position of the arm is slaved to the angular position of the boom, attached to the other end of the swingarm, so that the counterweight is in the vicinity of the axis of rotation of the pylon when the boom is raised, and deviates in a pendulum motion when the arrow s' tilts horizontally. This device does not assist the lifting operation for important lifting angles. This type of crane always requires a high torque lifting motor device.

The document EP 379448 discloses a luffing jib crane according to the preamble of claim 1 comprising a rotating pivot, on which is mounted the boom, a platform carrying the boom lift and load lifting mechanisms and a movable counterweight, attached to the back of the pivot, opposite the arrow. The counterweight is mounted rolling on straight members of the platform, which have a slight slope directed towards the axis of the pylon. The counterweight is connected by a boom retaining tie, via a deflection pulley, so as to deviate from the pylon when the boom is lowered to the horizontal and to approach the pylon when the boom is raised. This device makes it possible to compensate the moment of the dead weight of the boom on the pylon structure, but the lifting requires a mechanism providing a very important torque.

It is also possible to use port-type cranes, with articulated, articular horizontal distributing boom, moving the load, respectively moving the latter closer to the pivot axis of the crane by deployment, respectively folding the boom. The moment of the self-weight of an arrow of this type varies considerably between the extended position of the arrow and the position folded towards the pylon. It is difficult to balance these stress variations with a single moving counterweight.

The document DE 1260733 describes a crane of this type and proposes to reduce or even eliminate the counterweight and to resort to a distribution the end of the dart tip, cooperating with an arrow retaining cable acting on the end of the counter-dart via punches and return pulleys, both of these cables being actuated by winches. The implementation of these winches requires engines with very high torque.

The patent FR 2605619 describes a collapsible hoist that combines the effects of an articulated boom booms with those of a luffing jib crane, giving it versatility. However, because of the design of the articulations of the distributing boom, this crane always has a minimum important range. In addition, the hook height gain when the tip of the boom is raised remains relatively low, can not exceed an angular amplitude equivalent to 30 ° relative to the horizontal.

The patent application EP 1057776 of the applicant describes a collapsible lifting gear with directional distributing boom capable of working in articulated mode or in lift mode. The boom consists of an arrow leg whose first end is mounted at the top of the pylon, and a dart mounted in articulation on the second end of the jib foot, this jib being delimited by this two-part hinge, know a counter-dart and a dart tip. The counter-jib and the portion of the jib foot proximate this hinge are shaped so that the jib foot and the jib can align with the luff-work mode, increasing both the horizontal reach and the height. maximum under hook of the machine. This device uses a distribution cable not maintained by guides over a large length when the boom is almost fully deployed, resulting in problems of stability in rotation and distribution under load and headwind.

The patent application WO 02/04336 the applicant describes folding lifting equipment and tower cranes, with arrows adjustable, articulated, tilting and tilting dispensers. The portion of the arrow foot adjacent to the dart and the counter-dart have conjugate shapes allowing the dart tip to align with the boom foot in a work-up mode. A system of jacks is arranged at the joint between the jib foot and the jib to ensure the deployment and folding of the jib in horizontal or tilting articulated working mode. A mobile counterbalance system enables the crane to be balanced in all working positions: this system comprises in combination a fixed counterweight, for example at the end of the platform of the mechanisms, a main counterbalance counterweight and a second oscillating counterweight corrector. The adjustment of the masses and the positions of the three counterweights makes it possible to balance these cranes optimally in the different working modes that can be tilted, tilted and articulated.

However, the operation of such a counterweight system can be tricky to adjust. The length of the pendulum counterbalance arm causes considerable bulk below the platform. Moreover, the mechanism of the articulation of the boom, consisting of jacks, is relatively expensive, its control lacks precision and its weight contributes to weigh down the entire boom.

The object of the present invention is to provide a lifting device of the type defined entry which does not have the disadvantages mentioned above.

The object of the present invention is in particular to propose a hoist having the same versatility of use character as that described in the document WO 02/04336 while lowering the manufacturing cost, simplifying the implementation and, in addition, reducing the footprint below the platform.

These goals are achieved by means of a counterweight controlled by following a variable slope guide (α), integral with the rotating pivot, supporting said counterweight, arranged opposite the arrow, and whose slope variations (α) are chosen so that the counterweight exerts a set of variable forces on said boom and on the structure of said machine, helping to balance the machine during the movements of deployment / folding of the boom articulated working mode.

For this purpose, the present invention relates to a lifting and handling gear articulated directional boom articulated, comprising a pylon with a rotating pivot, an articulated boom comprising an arrow foot, articulated at its first end to the top of the pylon by a horizontal axis of rotation, a dart hinged in rotation by a horizontal hinge pin at the second end of the boom foot, an arrow retainer assembly comprising at least one punch, an arrow retainer and a movable counterweight connected to the boom by said holding sling, and slaved to follow a variable slope guide (α), the guideway being arranged opposite the boom and supporting said counterweight, characterized in that the track guide is rigidly fixed to the pivot pivot, and has in a portion (A) closer to the pylon a slope (α _A ) lower than the slope (α _B ) in at minus a portion (B) further from the pylon, the slope (α _A ) making an angle of 2 ° to 25 ° with the horizontal and the slope (α _B ) making an angle of the order of 15 ° to 85 ° with the horizontal, and in that the variations of slope (α) are chosen so that the counterweight exerts a set of variable forces on said boom and on the structure of said machine, contributing to balance the machine during the movements of Deployment / folding of the boom in articulated work mode.

The movable counterweight exerts, simply by means of the one or more boom retaining slings, a traction on this boom, whose intensity is a function of the local slope of the guide channel at the position of the counterweight. The mobile counterweight also exerts a bearing force on the guideway, which results in a torque exerted on the structure of the machine integral with the guideway, this torque being a function of the distance between the counterweight and the axis of the pylon. , and also from the local slope to the position of the counterweight.

The boom restraint assembly of the hoist according to the invention may comprise only one retaining sling. However, it is preferable to use a set of two slings and two punches with their respective return pulleys, the slings being arranged and attached on either side of the arrow, arranged symmetrically with respect to the plane of symmetry thereof. . The following description describes, for the sake of didactic simplification, a hoist equipped with a retaining sling. It applies mutatis mutandis to a machine equipped with two slings.

The guideway according to the invention is arranged opposite the arrow, that is to say seen in vertical projection on a horizontal plane, it extends in the opposite direction of the projection of the arrow, relative to the axis of rotation of the pylon. On the other hand, in lateral view, it presents a curved profile, the slope variations being chosen by the manufacturer according to the efforts required by the arrow.

The guideway may have two or more portions of constant but different slopes, preferably interconnected by a rounded. The guideway may have a more complex profile. The guideway may have a curvilinear profile, in particular a sigmoidal profile.

Preferably, to minimize frictional forces, the mobile counterweight is provided with rolling means, such as wheels or rollers, and the guideway may comprise one or more rails on which said rolling means roll. Such a rolling path can be achieved by means of a pair of curved rails, parallel to each other, and the counterweight can consist of a roller carriage, movable on these rails, and ballast elements carried by the said carriage.

The guide track could also consist of a plurality of rollers on which the mobile counterweight slides, or any equivalent mechanical system.

A counterweight of weight P placed on the guide track, when it is located at a distance x from the axis of the pylon, in an area where the guideway has an angle α with the horizontal, on the one hand a restoring force F on the boom via the holding sling and the return pulleys, and on the other hand a bearing force on the guideway which generates a torque C acting on the structures of the crane, opposing the torque exerted by the own weight of the boom and the lifting load on the pylon.

$$\mathrm{C}\mathrm{\cong }\mathrm{P}\mathrm{.}\mathrm{x}$$

As a first approximation, these forces correspond to the two components of the vector P, respectively parallel and perpendicular to the guideway, and $$\mathrm{F}\mathrm{\cong }\mathrm{P}\mathrm{.}\mathrm{sina}$$

$$\mathrm{VS}\mathrm{\cong }\mathrm{P}\mathrm{.}\mathrm{x}$$

According to the invention, α varies as a function of x, the function α (x) being determined by the choice of the curvilinear profile of the guideway made by the manufacturer of the crane. The distance x of the counterweight relative to the axis of the pylon itself is a decreasing function of the angle that the foot of the arrow makes with the horizontal, because of the connection via the sling retaining, the choice of profile of the guideway according to the invention allows to modulate a return component of the boom, so that all of the restoring and support forces automatically balance the crane during the movements of the crane in operating mode. articulated work, and can assist the mechanism (s) operating the deployment and the folding of the boom, such as cylinders, motors and winches. If the crane operates in lift mode, this return component automatically assists the boom lift mechanism.

The relations (I) and (II) are given only as an illustration of the principle of the invention. They do not take into account corrective factors related to the elevation positions of the center of gravity of the counterweight, the attachment points of the sling (s) and the return pulleys. These equations can not therefore define limitations of the scope of protection sought.

The use of this variable return component in the tilting, hinged or tiltable work mode allows the use of mechanical lift devices with lower maximum torque and lower power.

The use of this variable return component of the counterweight also allows the use of less powerful devices, lighter and more economical than a system of hydraulic cylinders, such as electric winches, to operate the boom in articulated work mode for horizontal distribution of loads.

The reaction time of an electric motor system is faster than that of a system based on hydraulic cylinders, which is penalized by the long length of the pipes. The use of an electric motor system therefore improves the comfort of the crane operator. Finally, the maintenance is also smaller and easier.

• à des engins de levage à flèche distributrice articulée, ou
• à des engins à flèche relevable, ou
• à des engins à flèche articulée et relevable, ou encore
• à des engins à flèche articulée, relevable et fléchette inclinable.

The counterweight system according to the invention can be applied

• articulated dispensing jib cranes, or
• with luffing jibs, or
• to articulated and liftable boom gear, or
• with articulated, tilting and tilting jibs.

The counterweight system according to the invention can be used not only for tower cranes, but also for lifting machines with folding towers, self-uprights.

The general architecture of such lifting gear, and particularly advantageous structures and shapes of jibs and darts are described in the document WO 02/04336 whose contents are incorporated in this application by reference. The counter-jib and the second end of the jib foot may have conjugate prismatic profiles and come into contact with each other when the jib foot and the jib are aligned. According to other embodiments, the second end of the jib foot can have the shape of a fork with two branches and the counter-jib is housed in the space between the two branches. According to other embodiments, the boom foot consists of two parallel beams and the counter-dart is housed in the spacing between the two beams. When the jib foot is in the form of a fork or in the form of two beams, the jib may comprise an arrow / jib stop device such as those described in the document WO 02/04336 .

According to a preferred embodiment, the rotation of the dart around the second end of the jib foot is performed by means of a system of opposing cables wound and unwound by means of electric winches. According to a particular embodiment, these winches, a portion of the cables and their return pulleys can be housed in the foot of the arrow. More specifically, the winches are housed at the base of the boom foot to obtain a better balance of the crane by reducing as much as possible the own weight of the winches to the center of the tower. This location improves maintenance because the winches are in the vicinity of the revolving pivot, i.e. the platform.

According to another preferred embodiment, the rotation of the dart around the end of the jib foot is carried out by means of a gear system comprising a motor, a pinion and a toothed segment. According to a particular embodiment, the motor is fixed on the jib foot and drives, via a pinion, a circular toothed segment integral with the dart.

• la fig. 1 présente deux vues schématiques, de profil en 1a et de face en 1b, d'une grue de chantier selon l'invention, montée sur un chenillard, flèche repliée et relevée, la fléchette étant rabattue contre le pied de flèche;
• la fig. 2 est une vue schématique de profil, d'une voie de guidage de contrepoids;
• la fig. 3 compare les variations de la force de rappel d'un contrepoids selon l'invention avec celles de contrepoids de l'art antérieur;
• la fig. 4 est une vue de profil d'un contrepoids;
• la fig. 5 est une vue de face d'un contrepoids;
• les fig. 6a et 6b sont deux vues schématiques, de profil, d'une grue à flèche relevable;
• les fig. 7a, 7b et 7c sont trois vues schématiques, de profil, d'une grue à flèche articulée;
• le groupe de fig. 8, c'est-à-dire 8a, 8b, 8c, 8d et 8e, sont des vues de détail illustrant le fonctionnement de la grue des fig. 7a, 7b et 7c;
• les fig. 9a, 9b sont deux vues schématiques de profil d'une grue opérant en mode de travail à fléchette inclinable;
• les fig. 10a 10b et 10c sont trois vues schématiques illustrant un autre mode d'exécution de grue à flèche articulée;
• la fig. 11 est une vue d'ensemble, de profil, d'un exemple de réalisation de grue-tour.

Other features and advantages of the invention will become apparent to those skilled in the art from the following description of particular embodiments in connection with the drawing, in which:

• the Fig. 1 presents two schematic views, of profile in 1a and of face in 1b, of a construction crane according to the invention, mounted on a chaser, folded arrow and raised, the dart being folded against the foot of arrow;
• the Fig. 2 is a schematic side view of a counterweight guideway;
• the Fig. 3 compares the variations of the restoring force of a counterweight according to the invention with those of counterweight of the prior art;
• the Fig. 4 is a side view of a counterweight;
• the Fig. 5 is a front view of a counterweight;
• the Fig. 6a and 6b are two schematic views, in profile, of a luffing jib crane;
• the Fig. 7a, 7b and 7c are three schematic views, in profile, of an articulated boom crane;
• the group of Fig. 8 , ie 8a, 8b, 8c, 8d and 8e, are detail views illustrating the operation of the crane of Fig. 7a, 7b and 7c ;
• the Fig. 9a, 9b are two schematic profile views of a crane operating in tilting jib work mode;
• the Fig. 10a and 10c are three schematic views illustrating another embodiment of articulated boom crane;
• the Fig. 11 is an overview, in profile, of an exemplary tower crane embodiment.

The Fig. 2 is a schematic view, in profile, of an embodiment of the guideway 1 of the counterweight 100. As an illustration, it has been shown with a ballast 110 in two different positions and with the support arms 108, 109 who wears it, the other elements of the crane having been removed for the sake of simplification. The guideway consists of two rails 2, 3 curvilinear and parallel, which are visible both, in section, on the Fig. 5 . However, in all the schematic side views showing the crane, only one rail is shown.

Depending on the overall size of the crane guideway 1 may have a length of the order of 5 to 20 meters. Zone A, the closest to the pylon, has a slight slope, making an angle α _A with the horizontal of 2 ° to 25 °. Moving away from the crane, the slope increases. In the area indicated by B on the Fig. 2 , the guide path can form an angle α _B of the order of 15 ° to 85 ° with the horizontal. Finally, in the area indicated by C, close to the distal end of the guideway with respect to the axis of the mast, the slope decreases again, the path forming an angle α _c of 2 ° to 45 °.

On the Fig. 2 , we have schematized the components of the forces that a mass of ballast exerts on the other parts of the crane. If the weight vector P is decomposed into its components respectively perpendicular and parallel to the axis of the track, we see that in zone A, the parallel component at way F _A is very small. The restoring force of the ballast on the restraining sling is weak, but it is sufficient to keep the sling stretched, the carriage tending to return to the pylon. By way of example, if the ballast mass is 20 tons and if the slope of α _A is 5 °, the restoring force F _A is of the order of 17 kN. The ballast essentially exerts a torque on the structure of the crane, which torque, at a distance x _A , is about Px _A.

In the zone indicated by B, the slope is maximum and, in the embodiment represented on the Fig. 2 , of the order of 50 °. The restoring force that the ballast exerts on the boom retaining sling becomes much larger. Subject to the position of the point of attachment of the restraining sling to the counterweight and the position of the return pulley, which is located near the distal end of the guideway, but which may be arranged on the latter, or above, or below, this restoring force corresponds approximately to the component of the weight P parallel to this guideway, ie F _b .

In zone C, slightly less steep, this restoring force decreases again. Those skilled in the art will readily observe that if in zone C the slope remains constant and equal to the maximum value reached in zone B, the restoring force would retain in zone C the maximum value of F _b reached in the zone B.

The Fig. 3 represents the restoring force as a function of the distance between counterweight and pylon for three different counterweight systems. In all three systems, the total weight of the counterweight is 20 tonnes. Curve (a) represents the restoring force for a rectilinear profile guideway corresponding, for example, to that described in FIG. EP 0379448 with α = 5 °. Curve (b) represents the restoring force of a pendular counterweight hung on the end of a 12-meter long oscillating arm, which is bulky, moving in the space below the platform.

Curve (c) represents the return force obtained by means of a guideway according to the invention similar to that of the Fig. 2 , for which the slope is 3 ° near the pylon, then increases to a maximum of 53 ° at a distance of 9 meters, then decreases, the slope being of the order of 30 ° at the end of the way. The profile of the curve (c) is determined by the choice of the profile of the guide way, that is to say by the variations of slope between the zones A, B and C represented on the Fig. 2 .

The Fig. 4 and 5 represent, respectively of profile and face, an embodiment of the counterweight according to the invention. In these figures, the carriage is generally designated 101. The chassis of the carriage consists of four longitudinal beams, two outer beams 102 and two inner beams 103, connected by four transverse beams 104. Each beam 102, 103 carries two rolling devices. with rollers 105 which roll on the two curvilinear rails 2 and 3 constituting the raceway. The outer longitudinal beams 102 each carry three substantially vertical support beams, namely an upper beam 106 and two lower beams 107, constituting three points of support. Each longitudinal beam 102 also carries two support arms 108, 109. These support arms are preferably mounted inclined to eliminate the play between ballast elements, which are supported against each other, and against the support points. . The support arms, and the corresponding fastening means of the ballast elements are arranged so that the level of the center of gravity of the counterweight is close to, and preferably substantially coincides with the level of the raceway at the location where is the trolley, to avoid swaying movements of the crane.

According to an alternative embodiment, the support arms can be mounted on joints to fold them, in order to reduce the size of the carriage during transport. Each pair of unfolded arms 108, 109 receives one or more weight (s) of ballast 110. As shown by the Fig. 2 and 5 these ballast masses may consist of concrete plates provided with two holes for hanging them on the support arms 108 and 109. The holes 111 may be made in the form of two squares rotated angularly by 90 ° relative to each other. at the other and spaced apart from one another so that the support arms 108 and 109 are placed in the corners as shown in FIG. Fig. 2 . Those skilled in the art will readily understand that this arrangement allows both an easy placement of the weights on the support arms, the dimensions of the holes 111 being significantly greater than the diameter of the support arms 108 and 109, and on the other hand avoids a tilting masses and corresponding shocks when the movable carriage moves between the zone A and the areas B and C of the raceway. The establishment of the weights on the carriage is completed by the establishment of a set of bars 113 and safety cables 112 between the support arm and support beams of the carriage.

The plates of ballast 110 offer to the lateral wind a large surface. The action of the wind on it therefore generates a torque that partially compensates for the torque that the wind exerts on the boom. This arrangement and this conformation of the ballast plates thus assists the horizontal rotation of the rotating part above the pivot, that is to say the distribution of the charges.

The skilled person will also find on the Fig. 5 that the two curvilinear rails 2 and 3 are connected by a set of transverse beams 4 thus constituting a kind of platform which can receive one or more winches 17, punches or tie rods 6.

The Fig. 1a and 1b show an articulated boom crane, with the boom raised to the maximum and the dart folded against the boom foot, on a rolling chassis. In the position where the foot of the boom is fully raised, the ballast masses come very close to the pylon, framing it on both sides, as shown in the diagram. Fig. 1b . In this position, the ballast masses on the one hand and the mass of the boom on the other hand exert relatively low stresses on the tower and the rolling chassis of the crane, so that the displacement of the standing crane is possible on the yard, by means of a chase, without there being need to disassemble the crane to move it. Jacks 33 can raise and adjust the level of the crane during such a displacement.

The Fig. 6a and 6b show the operation of the counterweight on a hoist whose boom operates in working mode. The Fig. 6a shows the machine, the arrow 10 is almost horizontal, in maximum range position. The counterweight 100, represented in a simplified manner by a square ballast and a set of rollers, rolls on the guideway 1 and is connected to the boom only by the sling (s) 11, so that its displacement is enslaved to the displacement of the arrow simply and only by this (these) sling (s) 11. On the Fig. 6a , the counterweight 100 is in the distal zone of the lane 1 relative to the axis of the tower. On the Fig. 6b , the arrow 10 is raised in the minimum range position. The boom retention sling 11 is fixed at its first end to the counterweight 100. It passes over a deflection pulley 9 arranged at the distal end of the guideway and a second deflection pulley 8 arranged at the top of the punch. 7. The other end of the retaining sling 11 is fixed at 12 to the arrow, at the same level as the bridge 13. The bridge 13 serves as a point of attachment to the lifting device. The lifting device may consist of several parts, namely a lifting tie 14, connecting the lifting bridge to a pulley or a block 16, and a lifting cable 15, which can make several strands of muffle. The lifting cable 15 is connected to a winch of lift 17 whose coil is arranged on the platform secured to the guideway.

The boom retaining sling 11 cooperates with the lifting engine device to raise the boom. Referring to the Fig. 3 it will be noted that its contribution is important in the median positions and the positions close to that shown by the Fig. 6a , that is to say when a large lifting torque is necessary, and weak in the positions close to that of the Fig. 6b , that is to say when the lifting motor device needs only a low torque. The counterweight system according to the invention therefore makes it possible to reduce the maximum nominal torque of the lifting device. If it is desired to obtain a return component F assisting the lifting device to the maximum in positions close to that of the Fig. 6a , the guideway may have its steepest slope in its distal portion.

It will be noted that the arrow 10 shown on the Fig. 6a and 6b can be a rigid boom or an articulated boom like that of the Fig. 7c .

The Fig. 7a, 7b and 7c illustrate the operation of an articulated boom operating in horizontal articulated distribution mode. The Fig. 7a , similar to Fig. 1a , shows the arrow in the position of minimum range, dart 18 folded against foot of arrow 19. The Fig. 7c shows the arrow 10 in a position similar to that of the Fig. 6a in the maximum range position, the jib foot and the jib being aligned.

The Fig. 7b shows the arrow in an intermediate deployment position. The skilled person will note in particular that in the position illustrated by the Fig. 7b , the counterweight 100 is about halfway and the traction component on the retaining sling 11 of the boom is important. The arrow lift tie 14 attached to the bridge 13 passes on the end 21 of the counter-dart 20 which returns it. The hinge 32 formed by a horizontal axis of rotation between the foot of the boom 19 and the dart 18 delimits the latter between dart tip 22 and against-dart 20. It is at this level that is attached in 12 the sling 11. The rotation of the dart about the hinge axis 32 is achieved by means of two opposing cables 23 and 24. The attachment point of the cable 23 is located at the end of the counter -flash 20 to obtain the largest lever arm relative to the hinge 32, to reduce the forces in the cable 23 and the required power of the electric winch 25 which actuates. In order to obtain a homogeneous behavior of the two opposing cables, the point of attachment of the cable 24 on the dart 22 is situated approximately at the same distance as the cable 23 with respect to the hinge 32. A pulley 29 of the cables 23, 24 is arranged in the foot of the arrow, in an area close to the articulation 32 between the foot of the arrow and the dart, as illustrated by FIG. figure 7b . The winding winches 25, 26 of the cables 23 and 24 are arranged in the jib foot near the articulation 27 of the first end of the jib foot at the top of the tower in order to obtain a better balance of the crane. bringing as much as possible the dead weight of the various elements of the winches 25 and 26 towards the center of the pylon. This location also improves maintenance because the winches are close to the swivel.

The attachment point 12 of the sling 11, located on the dart 18, describes an arc around the hinge axis 32 to optimize the movement of the counterweight to improve the balance of the crane.

The operation of the horizontal distribution from the minimum range ( Fig. 7a ) to the maximum range, Fig. 7c , in articulated work mode is illustrated in more detail by the Fig. 8a, 8b, 8c, 8d and 8th . The Fig. 8a shows the area of the arrow surrounding the 32 foot joint of arrow / dart in the position of the Fig. 7a . It will be noted that the boom retaining slings (s) pass (s) slightly below and to the right of the articulation 32 foot of arrow / dart; the lifting cable 15 and the lifting lever 14 boom run over the end 21 of the counter-dart and are a little to the left of the hinge 32 between the jib and arrow. The cables 23 and 24 have antagonistic effects. From this position, the upper cable 23 is controlled by the crane operator and the lower cable 24 is unwound. The upper cable 23 is deflected by the upper rod 30.

In the position shown by the Fig. 8b , the upper cable 23 pulls on the counter-dart, in order to continue the deployment operation, the upper rod 30 always deflecting the upper cable 23. The lower cable 24 is then driven by the upper cable 23, the speed being controlled by the crane operator.

At the stage shown by the Fig. 8c , the upper cable 23 always pulls on the counter-dart, in order to continue the deployment movement, but the upper rod 30 no longer deflects the upper cable 23. The lower cable 24 is always carried by the upper cable.

At the stage shown by the Fig. 8d , the upper cable 23 always pulls on the counter-dart, to continue to deploy the boom, and the lower cable 24 is always carried by the upper cable. It will be noted that the lower cable 24 comes into contact with the lower rod 31 and that the retaining sling 11 has passed the hinge 32 between the jib and the jib.

In the position illustrated by the Fig. 8th the lifting tie 14 is no longer in contact with the end 21 of the counter-dart. The lower cane 31 increases the traction angle of the lower cable 24 in order to reduce the efforts of this and to ensure the stability of the elements around the joint 32.

For the fraction of the deployment that lies between Fig. 8d and 8th it may be preferred that the return force contribution F of the boom retaining sling 11 decreases in favor of the torque C. In this case, the distal zone of the guide lane 1 indicated as zone C on the Fig. 2 may have a lower slope than the slope of zone B.

The Fig. 9a and 9b illustrate the tilting jib work mode of the articulated boom previously described in relation to the groups of Fig. 7 and 8 . Between the two positions of Fig. 9a and 9b the boom foot 19 does not move, it bears against an abutment device 33. Such abutment devices are known in the state of the art. The mobile counterweight 100 is located in both positions in a low slope area of the raceway, near the pylon. However, because of the non-zero distance between the attachment point 12 of the boom retaining sling and the hinge 32 between the jib and dart, this attachment point 12 describes an arc around the articulation 32 of the arrow, driving the counterweight in a limited displacement. The resulting momentum variations of the counterweight to the pylon balance the variations in the moment of the weight of the boom due to the rotation of the dart. The rotation of the dart about the hinge 32 with the jib foot is provided by the opposing cable systems 24 and 23 in the same manner as explained above in connection with the group of Fig. 8 .

In all the positions of the range defined by the crane operator, the stability of the end of the boom is provided by a electromechanical brake with no current installed on the motors of the cables 23 and 24.

In another embodiment of the hoist according to the invention, illustrated by the Fig. 10a, 10b and 10c , the set of antagonistic cables 24 and 23 with their winding and unwinding winches 25, 26 arranged in the jib foot is replaced by a gear system 200, consisting of a motor 201, a gear 202 and a toothed segment 203, arranged at the hinge 232 between the jib 204 and the jib 205. The electric motor 201 is fixed on the jib foot, it drives a pinion 202 which itself meshes with a circular toothed segment 203 integral with the dart, to ensure the rotation of the dart around the hinge 232 between the foot of the arrow and the dart. The arrangement and function of the boom retainers 11 and the lift tie 14 are the same as those of the embodiments described above.

Example: versatile tower crane

The Fig. 11 schematically illustrates an exemplary embodiment of tower crane according to the invention. The base frame has an impregnation of 5 x 5 meters and carries a basic weight of 46 tons. The base frame is surmounted by a tower having a cabin height of 31 meters and a rotating pivot. This one carries the platform, the cabin and the arrow as well as the guide way on which the mobile ballast circulates. The total weight of the idling crane in service is 111.6 tons.

The guiding track, integral with the rotating pivot at the top of the pylon, extends from the pylon up to a distance of 12 meters from it. It consists of a pair of rails connected by spacers. Each rail comprises a first straight portion of slope 5 °, extending from the pivot pivot to a distance of 6 meters, a second rectilinear portion of slope 29 °, extending from a distance of 6 meters up to at a distance of 8 meters from the pylon, and a third rectilinear portion of slope 43 °, corresponding to the last two meters of the track. Between the first and second rectilinear portions on the one hand and the second and third rectilinear portions on the other hand are located two intermediate portions curved, forming the rounded rails, which are therefore generally curvilinear.

The guideway, which is also the platform, carries the boom lifting winch which has a power of 22 kW. The guideway is surmounted by a set of punches and tie rods carrying the pulleys. The whole stands at a height of about 41.6 meters.

On this guideway runs a roller carriage carrying on each side respectively two concrete plates weighing 6.5 tons each.

The boom foot, near its articulation with the rotating pivot of the tower, the boom deployment / folding winches in articulated working mode with a power of 7.5 kW and the hoist winch of the load of a power of 45 kW. The corresponding return pulleys are also housed in the foot of the arrow near the joint with the dart. The operating mode of the articulated boom has been described above in relation to the Fig. 6a to 8e .

In articulated work mode, the crane can deliver a maximum load of 12 tons at reduced speed, or a load of 10 tons at normal speed, and this in an area from 2 to 20 meters from the foot of the pylon. The distributable load decreases at a greater distance from the foot of the pylon. The maximum load is 5.6 tonnes at reduced speed and 4.7 tonnes at normal speed at the maximum working range, that is to say 47 meters. The speed of distribution can vary from 0 to 60 meters per minute.

In work-up mode, the maximum distributable load is 12 tonnes when the range is between 5 and 20 meters. The maximum load is reduced to 5.6 tons at a maximum range of 47 meters. The maximum height under hook in lift mode is 80 meters. The movement speed in lift mode can vary from 0 to 30 meters per minute.

When the crane is dismantled, it can be transported in parts by means of five trailers of lengths between 6 and 12 meters, each of the trailers carrying a set of parts from 19.5 to 25 tons.

If the user plans to use the crane exclusively in articulated working mode, in horizontal distribution, the boom lift winch can be removed and the lift block is replaced by two tie rods. This reduces the sale price of the crane and the number of parts.

Claims (18)

1. Loads lifting and handling appliance with an articulated and orientable placing jib, comprising a mast with a rotating pivot, an articulated jib (10) comprising a jib foot (19), articulated at its first end to the top of the mast via a horizontal axis of rotation (27), a fly jib (18) articulated in rotation via a horizontal axis of articulation (32) at the second end of the jib foot, a jib-retaining assembly comprising at least one post (7), a jib-retaining sling (11) and a moving counterweight (100), connected to the jib by said restraining sling, and controlled to follow a guideway (1) with variable slope (α), the guideway (1) being arranged opposite the jib and supporting said counterweight, characterised in that the guideway is rigidly attached to the rotating pivot and has, in a portion (A) closer to the mast, a slope (α_A) smaller than the slope (α_B) in at least one portion (B) farther from the mast, the slope (α_A) forming an angle of 2° to 25° with the horizontal line and the slope (α_B) forming an angle of the order of 15° to 85° with the horizontal line, and in that the variations in slope (α) are chosen in such a way that the counterweight exerts a set of variable forces on said jib and on the structure of said appliance, contributing to balancing the appliance during movements of extension/withdrawal of the jib in articulated work mode.
2. Lifting appliance according to claim 1, characterised in that the sling (11) passes, starting from the counterweight, on a feed pulley (9) positioned at the distal end of the guideway and on a second feed pulley (8) positioned at the top of the post (7).
3. Lifting appliance according to one of claims 1 or 2, characterised in that the guideway (1) has a curved profile.
4. Lifting appliance according to one of claims 1 or 2, characterised in that the guideway (1) has a sigmoidal profile.
5. Lifting appliance according to one of the previous claims, characterised in that the guideway (1) consists of a pair of parallel curved tracks (2, 3) and in that the counterweight comprises a moving trolley (101) comprising rolling means (105) rolling on said tracks and ballast elements (110) carried by said trolley.
6. Lifting appliance according to claim 5, characterised in that the trolley (101) comprises a chassis (102, 103, 104) and, on each of the lateral sides of the chassis, support elements (108, 109) for holding and carrying said ballast elements (110) on either side of the tracks in such a way that the level of the centre of gravity of the counterweight is close to the level of the guideway.
7. Lifting appliance according to one of claims 5 or 6, characterised in that said support elements (108, 109) are pairs of arms arranged in a tilted position and in that said ballast elements (110) consist of plates, each one having holes (111) with upper surface greater than the section of the support arms (108, 109) and configured in such a way that a ballast plate suspended from a pair of associated support arms is maintained in an immobile position in relation to said trolley (101) whatever the position of the trolley on the guideway (1) and parallel to said guideway (1).
8. Lifting appliance according to claim 7, characterised in that said support arms are foldable.
9. Lifting appliance according to any one of the previous claims, characterised in that it comprises a jib raising device (14, 15, 17) making the appliance capable of working in articulated mode and in raisable mode, and in that said fly jib has on either side of its axis of articulation (32) at the jib foot respectively a fly jib tip (22) and a counter fly jib (20), said second end of the jib foot and the counter fly jib having conjugated shapes allowing the fly jib tip to come into an aligned position with the jib foot in the raisable work position and in that the slope variations of the guideway (1) are chosen in such a way that the variable traction on the jib assists the raising device and/or the changes in configuration of the jib associated with a change in work mode.
10. Lifting appliance according to any one of the previous claims, characterised in that the end of said jib-restraining sling (11) is attached to the fly jib.
11. Lifting appliance according to claim 10, characterised in that the point of attachment (12) of the end of the jib-restraining sling (11) is positioned between the fly jib tip (22) and the counter fly jib (20).
12. Lifting appliance according to claim 11, characterised in that said point of attachment (12) is arranged at a distance from the articulation (32) between the jib foot and fly jib such as to describe an arc of circle around the axis of articulation (32), and in that said jib-restraining sling (11) crosses the axis of articulation (32) of the jib foot/fly jib during extension of the jib in articulated work mode between the position of minimal extension and the position of maximum extension.
13. Lifting appliance according to one of the previous claims, characterised in that the rotation of the fly jib (18) around the jib foot/fly jib articulation (32) is driven by means of a system of counteracting cables (23, 24).
14. Lifting appliance according to claim 13, characterised in that the first cable (23) is attached to the end of the counter fly jib (20) and in that the second cable (24) is attached on the tip of the fly jib, at around the same distance from the articulation (32) as the distance from the attachment point of the cable (23) in relation to the articulation (32).
15. Lifting appliance according to claim 13 or 14, characterised in that said system of counteracting cables (23, 24) comprises electric winches (25, 26) and feed pulleys (29) housed in the jib foot (19).
16. Lifting appliance according to claim 15, characterised in that the electric winches (25, 26) are housed in proximity to the first end of the jib foot (19) and the feed pulleys (29) in proximity to the second end of the jib foot (19).
17. Lifting appliance according to one of claims 1 to 12, characterised in that the rotation of the fly jib (205) around the end of the jib foot (204) is performed by means of a gear wheel system (200) comprising an electric motor (201), a pinion (202) and a cogged segment (203).
18. Lifting appliance according to claim 17, characterised in that said electric motor (201) is attached on the jib foot (204) and drives, via said pinion (202), a circular cogged segment (203) integral with the fly jib (205).

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