Method for controlling a crane for selecting and applying a preferential load curve according to the inclination of a boom structural element

Abstract

A crane control method (1) for selecting and applying a preferred load curve adapted to a working configuration of a crane comprising a mast (2) supporting a luffing jib (3) comprising at least one structural jib element (31; 32), with: - a measurement of the actual inclination of the structural jib element in the working configuration by means of an inclinometer (61; 62); - an automated selection of the preferred load curve as a function of the actual inclination of said structural jib element, the latter being selected from a plurality of load curves stored in a memory (50) and calculated beforehand for several inclinations of said structural jib element; - a control step implementing an application of said preferred load curve for lifting and moving maneuvers of a load along the jib in the working configuration.

Description

[Technical field]

[0001] The invention relates to a crane control method for selecting and applying a preferential load curve adapted to a working configuration of a crane. It also relates to a crane comprising a mast supporting a luffing jib and means for implementing such a crane control method.

[0002] The invention finds a preferred, and non-limiting, application for an automated assembly crane with a luffing and folding jib. [State of the art]

[0003] Such a crane comprises a mast, generally of the foldable mast or telescopic mast type, supporting a raisable and foldable boom comprising structural boom elements articulated together. In the context of the present description, such a self-erecting crane is configurable between a transport configuration in which the mast and the boom are brought together or folded on themselves or side by side, and at least one working configuration in which the mast is vertical and the boom is unfolded to allow lifting and moving maneuvers of a load along the boom.

[0004] This type of crane can have several working configurations, including: a configuration in which the boom is fully extended (so that the boom offers its greatest length) and extends substantially horizontally, a configuration in which the boom is fully extended and is inclined relative to the horizontal, in other words the boom is raised relative to the horizontal, such a working configuration being called a fir-tree configuration, the inclination of the boom making it possible to bring the load closer or further away and thus at the same time avoid raising the crane too high; a configuration in which the boom is partially extended, with a boom tip in the retracted or non-extended position (so that the boom offers a reduced length) and extends substantially horizontally;a configuration in which the boom is partially extended, with a boom tip in a retracted or unextended position, and is inclined relative to the horizontal (in other words the boom is raised in a fir tree).;

[0005] These configurations can also be associated with several heights of the boom from the ground, also called height under hook.

[0006] Once the crane is assembled, an assembler then selects a load curve adapted to the working configuration of the crane; it being noted that this load curve will depend on the working configuration of the crane, such as the length of the boom, the height of the boom, the inclination of the boom. Also, an error in the selection by the assembler of the load curve adapted to the actual working configuration of the crane can have serious consequences, such as damage or even collapse of the lifting and handling device.

[0007] The state of the art can also be illustrated by the teachings of document WO2016 / 128122 which proposes a method for monitoring a crane equipped with a luffing jib on which an inclinometer is provided, comprising monitoring the load carried and the angle of inclination of the jib to deduce therefrom the torques exerted on the jib in a clockwise direction, as well as monitoring the guying force to deduce therefrom the guying torque exerted on the jib in an anticlockwise direction, with the aim of determining a difference between these torques and when this difference exceeds a certain given tolerance threshold, then the method provides for emitting an error and / or deactivation signal. [Summary of the invention]

[0008] The present invention aims to resolve all or part of this drawback, by proposing a solution for knowing at least partially the actual working configuration of the crane, and automatically deducing the load curve adapted to this actual working configuration.

[0009] Thus, the invention proposes a crane control method for selecting and applying a preferential load curve adapted to a working configuration of a crane, such a crane comprising a mast supporting a luffing jib comprising at least one structural jib element, this crane control method implementing the following steps: an inclination measurement step implementing a measurement of an actual inclination of the boom structural element relative to a reference axis in the working configuration, by means of an inclinometer mounted on this boom structural element; a selection step implementing an automated selection of the preferred load curve as a function of the actual inclination of the boom structural element, such a preferred load curve being selected from a plurality of load curves stored in a memory and calculated beforehand for several inclinations of this boom structural element; a control step implementing an application of this preferred load curve for lifting and moving maneuvers of a load along the luffing boom in the working configuration of the crane.

[0010] Thus the invention proposes to evaluate the working configuration of the crane from a measurement of the inclination of at least one structural element of the boom, thus making it possible to understand whether the boom is horizontal or raised, and therefore making it possible to adapt the load curve according to such an inclination.

[0011] According to a variant, the structural element of the arrow, the actual inclination of which is measured, is chosen from: either a first structural boom element, forming a boom foot, which is articulated on the mast, or a second structural boom element which is articulated on the first structural boom element.

[0012] According to one feature, the elevating boom is foldable and comprises at least two structural boom elements hinged together, and wherein: the inclination measuring step implements a measurement of the actual inclinations of the two boom structural elements relative to the reference axis in the working configuration, by means of inclinometers mounted on said two boom structural elements; and the selection step implements the automated selection of the preferential load curve as a function of the actual inclinations of these two boom structural elements, the preferential load curve being selected from the plurality of load curves calculated beforehand for several inclinations of these two boom structural elements.

[0013] Such a solution is particularly advantageous because it bases the selection of the preferred load curve on the inclinations of two boom structural elements, thus allowing access to a greater number of crane working configurations, and in particular to working configurations in which the boom is partially extended.

[0014] According to one possibility, the two boom structural elements comprise a first boom structural element, forming a boom foot, which is hinged to the mast, and a second boom structural element hinged to the first boom structural element.

[0015] Alternatively, the luffing jib comprises a third boom structural element, forming a boom tip, which is hinged to the second boom structural element and is movable between two positions including a retracted position in which the third boom structural element is folded and folded towards the second boom structural element, and a deployed position in which the third boom structural element is unfolded and extends in alignment the second boom structural element, wherein a position detection step implements detection of the actual position of the third boom structural element among its two positions, and wherein the selection step implements automated selection of the preferred load curve as a function of the actual inclinations of the two boom structural elements and the actual position of the third boom structural element,said preferential load curve being selected from the plurality of load curves calculated beforehand for several inclinations of the two structural boom elements and for the two positions of the third structural boom element.,

[0016] Thus, the selection of the preferred load curve is based on the inclinations of the first two structural elements of the boom, and also on the position of the third structural element forming the boom tip, which will allow access to an even greater number of working configurations of the crane, and in particular to working configurations in which the boom tip is deployed or retracted.

[0017] Alternatively, the position detection step (for detecting the actual position of the third boom structural element) is implemented by means of a detector selected from: an inclinometer mounted on the third boom structural member, or a position or proximity sensor that is mounted on the second boom structural member or the third boom structural member to detect the presence / absence of the third boom structural member in one of the two positions.

[0018] Thus, for this third structural boom element, it is possible to use an inclinometer (as for the first two structural boom elements), but alternatively it is possible to use a position or proximity sensor, because this third structural boom element is either in the deployed position or in the retracted position, without an intermediate position in the working configuration.

[0019] In a particular embodiment, the crane control method further comprises a height measurement step implementing a measurement of an actual height of the luffing jib relative to the ground in the working configuration, and in which the selection step implements the automated selection of the preferred load curve as a function of the actual inclination of the boom structural element and the actual height of the luffing jib, said preferred load curve being selected from the plurality of load curves calculated beforehand for several inclinations of said boom structural element and for several heights of the luffing jib.

[0020] Thus, the selection of the preferred load curve is also based on the actual height of the luffing jib (similar to the height under hook generally considered in the field of cranes), increasing the range of working configurations for the crane.

[0021] According to one possibility, the mast is a telescopic mast comprising mast structural members mounted in a telescoping manner, and the height measuring step is performed by means of a sensor which measures a level of telescoping between the mast structural members.

[0022] In a particular embodiment, the selection step is carried out by a control / command system, which control / command system is connected to the memory storing the plurality of load curves and to operating actuators of the crane to carry out the piloting step.

[0023] The invention also relates to a crane comprising a mast supporting a luffing jib comprising at least one jib structural element, such a crane further comprising: an inclinometer mounted on the boom structural element for measuring the actual inclination of the boom structural element relative to a reference axis in a working configuration; a control / command system connected to the inclinometer and to a memory storing a plurality of load curves previously calculated for several inclinations of said boom structural element; wherein this control / command system is configured to operate an automated selection of a preferential load curve as a function of the actual inclination of the boom structural element, this preferential load curve being selected from the plurality of load curves stored in the memory; and this control / command system is connected to maneuver actuators and is configured to control lifting maneuvers and movement of a load along the luffing boom in the working configuration of the crane, by applying the preferential load curve.

[0024] According to one feature, the raisable boom is foldable and comprises at least two structural boom elements articulated together and on which respective inclinometers are mounted to measure actual inclinations of the two structural boom elements relative to the reference axis in the working configuration, and the control / command system is configured to operate the automated selection of the preferential load curve as a function of the actual inclinations of said two structural boom elements, said preferential load curve being selected from the plurality of load curves calculated beforehand for several inclinations of said two structural boom elements.

[0025] According to another feature, the raisable boom comprises a third boom structural element, forming a boom tip, which is articulated on the second boom structural element and which is movable between two positions comprising a retracted position in which the third boom structural element is folded and folded towards the second boom structural element, and a deployed position in which the third boom structural element is unfolded and extends in alignment the second boom structural element, and a detector is configured for detecting an actual position of the third boom structural element among its two positions, and the control / command system is configured to operate the automated selection of the preferential load curve as a function of the actual inclinations of said two boom structural elements and the actual position of the third boom structural element, said preferential load curve being selected from the plurality of load curves calculated beforehand for several inclinations of said two boom structural elements and for the two positions of the third boom structural element.

[0026] In a particular embodiment, the crane comprises a height measuring device implementing a measurement of an actual height of the luffing jib relative to a ground in the working configuration, and the control / command system is configured to operate the automated selection of the preferential load curve as a function of the actual inclination of the boom structural element and the actual height of the luffing jib, said preferential load curve being selected from the plurality of load curves calculated beforehand for several inclinations of said boom structural element and for several heights of the luffing jib.

[0027] According to one feature, the mast is a telescopic mast comprising mast structural members mounted in a telescoping manner, and the height measuring device comprises a sensor which measures a level of telescoping between the mast structural members.

[0028] Other height measuring devices are possible, such as a laser rangefinder, an ultrasonic rangefinder, a camera, etc. [Brief description of the figures]

[0029] Other characteristics and advantages of the present invention will appear on reading the detailed description below, of a non-limiting example of implementation, made with reference to the appended figures in which: There Figure 1 is a schematic view of a crane according to the invention, with an illustration of four distinct working configurations; The Figure 2 is a partial schematic view of a first boom element, forming a boom foot, on which a first inclinometer is mounted; The Figure 3 is a partial schematic view of a second boom element on which a second inclinometer is mounted. [Detailed description of one or more embodiments of the invention]

[0030] In reference to the Figure 1, a crane 1 according to the invention comprises a mast 2 mounted on a platform 10 and supporting a luffing jib 3. The mast 2 may be a foldable mast comprising mast elements articulated together, or be a telescopic mast comprising mast structural elements 21, 22 mounted in a telescopic manner as in the example illustrated. The luffing jib 3 is a foldable jib comprising jib structural elements 31, 32, 33 articulated together.

[0031] In the illustrated example, the lifting boom 3 comprises three successive boom structural elements 31, 32, 33, namely: a first boom structural element 31, forming a boom foot, which is articulated on the mast 2, a second boom structural element 32, forming a central element, articulated on the first boom element 31, and a third boom structural element 33, forming a boom tip, articulated on the second boom element 32.

[0032] The first boom structural element 31 and the second boom structural element 32 form the first two boom structural elements 31, 32.

[0033] Crane 1 is configurable in several working configurations including the following four working configurations CW1, CW2, CW3 and CW4 which are shown diagrammatically on the Figure 1 : a first working configuration CW1 in which the luffing boom 3 is horizontal and completely unfolded, with its boom structural elements 31, 32, 33 which are unfolded, to extend substantially horizontally, in other words along a horizontal axis; a second working configuration CW2 (or fir-tree configuration) in which the luffing boom 3 is raised and completely unfolded, with its boom structural elements 31, 32, 33 which are unfolded to extend along an axis inclined relative to the horizontal at a given angle of inclination AN; a third working configuration CW3 in which the luffing boom 3 is horizontal and partially unfolded, with its first two boom structural elements 31, 32 which are unfolded and which extend substantially horizontally, in other words along a horizontal axis, and with its third boom structural element 33 which is folded backwards above the second boom element 32;a fourth working configuration CW4 in which the luffing boom 3 is raised and partially unfolded, with its first two boom structural elements 31, 32 which are unfolded and which extend substantially along an axis inclined relative to the horizontal at a given angle of inclination AN, and with its third boom structural element 33 which is folded backwards above the second boom structural element 32.;

[0034] In the third working configuration CW3 and in the fourth working configuration CW4, the third boom structural element 33 remains folded backwards, above the second boom structural element 32, which is advantageous for working with a shorter luffing boom 3, according to local working needs and conditions. In other words, the third boom structural element 33 is movable between two positions comprising: a retracted position (in the third working configuration CW3 and in the fourth working configuration CW4) in which the third boom structural element 33 is folded and folded towards the second boom structural element, and a deployed position (in the first working configuration CW1 and in the second working configuration CW2) in which the third boom structural element 33 is unfolded and extends in alignment the second boom structural element 32.

[0035] In the different working configurations, the mast 2 is deployed, and more specifically the mast structural elements 21, 22 are unfolded (in the folding mast version) or are deployed (in the telescopic mast version).

[0036] Furthermore, the crane 1 may be of the self-erecting crane type, and may thus also be configurable in a CT transport configuration (not shown) in which the mast 2 and the luffing jib 3 are brought together on themselves or side by side and extend horizontally, in order to form a transportable package, and more specifically in which the mast structural elements 21, 22 are folded on themselves (in the folding mast version) or are retracted on themselves (in the telescopic mast version) and the boom structural elements 31, 32, 33 are both folded on themselves and on the mast structural elements 21, 22.

[0037] The crane 1 is thus equipped with a motorized folding / unfolding system 7 which is coupled to the mast 2 and to the luffing jib 3 to act on the mast 2 and the luffing jib 3 to fold and unfold the crane 1 and thus move it from a working configuration to the transport configuration, and vice versa. In other words, this motorized folding / unfolding system 7 makes it possible to carry out configuration change operations implementing kinematics for folding and unfolding the luffing jib 3, and where appropriate for deploying and retracting the mast 2.

[0038] The crane 1 further comprises a control / command system 5 connected to maneuvering actuators (for example a lifting winch 81 for lowering / raising a lifting hook 9, and a distribution winch 82 for moving a distribution trolley 4 along the boom 3). This control / command system 5 is configured to control lifting and moving maneuvers of a load along the luffing boom 3 in the working configuration of the crane 1, by controlling the maneuvering actuators 81, 82, as a function of pilot commands exercised by a crane pilot on a pilot interface, and by applying a preferential load curve; such a preferential load curve defining maximum operating loads at the spans considered along the luffing boom 3. This control / command system 5 can for example be a microcontroller, a microprocessor, or an electronic control card.

[0039] According to the invention, the crane 1 comprises at least one inclinometer mounted on one of the boom structural elements 32, 32, 33 for measuring actual inclinations of this boom element relative to a reference axis, such as a horizontal axis or a vertical axis. In the example illustrated in the Figure 1 , the crane 1 comprises two inclinometers, namely a first inclinometer 61 and a second inclinometer 62, mounted on the first boom structural element 31 and the second boom structural element 32 respectively, for measuring the actual inclinations of this first boom element 31 and this second boom element 32 respectively.

[0040] In reference to the Figure 2 , the first inclinometer 61, fixed on the first boom structural element 31, can be placed near the articulation of the first boom element 31 on the top of the mast. With reference to the Figure 3, the second inclinometer 62, fixed on the second boom structural element 32, can be placed near the joint between the second boom structural element 32 and the first boom structural element 31.

[0041] Each of the two inclinometers 61, 62 may be an inclinometer with absolute angular measurement relative to the vertical or the horizontal, depending on the model. The inclinometers 61, 62 may be small-sized sensors which are directly mounted in a protected location in the structure of each boom structural element 31, 32.

[0042] It is also conceivable to provide a detector 63 which detects the actual position of the third boom structural element 33 among its two positions (retracted position and deployed position). This detector 63 may be an inclinometer mounted on the third boom structural element 33, or alternatively a position or proximity sensor which is mounted on the second boom structural element 32 or on the third boom structural element 33 to detect the presence / absence of the third boom structural element 33 in one of the two positions.

[0043] As visible on the Figure 1, the control / command system 5 is connected to the two inclinometers 61, 62 and to a memory 50 storing a plurality of load curves calculated beforehand for several inclinations of the first two structural boom elements 31, 32. Thus, the control / command system 5 is configured to operate an automated selection of a preferential load curve as a function of the actual inclinations of the first two structural boom elements 31, 32, the preferential load curve being selected from the plurality of load curves stored in the memory 50.

[0044] Advantageously, the control / command system 5 is connected to the two inclinometers 61, 62 and also to the detector 63, and the memory 50 stores a plurality of load curves calculated beforehand for several inclinations of the first two boom structural elements 31, 32 and for the two positions of the third boom structural element 33. Thus, the control / command system 5 is configured to operate an automated selection of a preferred load curve as a function of the actual inclinations of the first two boom structural elements 31, 32 and the actual position of the third boom structural element 33, the preferred load curve being selected from the plurality of load curves stored in the memory 50.

[0045] Thus, the control / command system 5 selects the preferred load curve which is adapted to the working configuration of the crane 1; this working configuration being dependent on the actual inclinations of the first two structural boom elements 31, 32 and the actual position of the third structural boom element 33. The invention thus makes it possible to select and apply a preferred load curve adapted to the working configuration of the crane 1.

[0046] To enhance this adaptation, it is conceivable to provide a height sensor 64 which allows a measurement of an actual height of the luffing boom 3 relative to the ground in its working configuration. In the context of a telescopic mast 2, this height sensor 64 may be a sensor which measures a telescoping level between the mast structural elements 21, 22. In this improved version, the control / command system 5 is connected to the two inclinometers 61, 62, possibly to the detector 63, and to the height sensor 64, and the memory 50 stores a plurality of load curves calculated beforehand for several inclinations of the first two boom structural elements 31, 32, for the two positions of the third boom structural element 33, and for several heights of the luffing boom 3.Thus, the control / command system 5 is configured to carry out an automated selection of a preferred load curve as a function of the actual inclinations of the first two boom structural elements 31, 32, of the actual position of the third boom structural element 33 and of the actual height of the luffing boom 3, the preferred load curve being selected from the plurality of load curves stored in the memory 50.

[0047] Thus, the control / command system 5 recovers measurement data from the different sensors 61, 62, 63, 64, and automatically applies the preferential load curve which is adapted to the working configuration deduced from this measurement data.

Claims

1. A drive method of a crane (1) for selecting and applying a preferential load curve adapted to a work configuration of a crane (1), said crane (1) comprising a mast (2) supporting a luffing jib (3) comprising at least one jib structural element (31; 32), said crane drive method implementing the following steps: - an inclination measurement step implementing a measurement of an actual inclination of the jib structural element (31; 32) with respect to a reference axis in the work configuration, by means of an inclinometer (61; 62) mounted on said jib structural element; - a selection step implementing an automated selection of the preferential load curve according to the actual inclination of said jib structural element (31; 32), said preferential load curve being selected from among a plurality of load curves stored in a memory (50) and calculated beforehand for several inclinations of said jib structural element (31; 32); - a drive step implementing an application of said preferential load curve for maneuvers of lifting and moving a load along the luffing jib (3) in the work configuration of the crane (1).

2. The drive method according to claim 1, wherein the luffing jib (3) is foldable and comprises at least two jib structural elements (31, 32) articulated with each other, and wherein: - the inclination measurement step implements a measurement of the actual inclinations of the two jib structural elements (31, 32) with respect to the reference axis in the work configuration, by means of inclinometers (61, 62) mounted on said two jib structural elements (31, 32); and - the selection step implements the automated selection of the preferential load curve according to the actual inclinations of said two jib structural elements (31, 32), said preferential load curve being selected from among the plurality of load curves calculated beforehand for several inclinations of said two jib structural elements (31, 32).

3. The drive method according to claim 2, wherein the two jib structural elements (31, 32) comprise a first jib structural element (31), forming a jib foot, which is articulated on the mast (2), and a second jib structural element (32) articulated on the first jib structural element (31).

4. The drive method according to claim 3, wherein the luffing jib (3) comprises a third jib structural element (33), forming a jib tip, which is articulated on the second jib structural element (32) and which is movable between two positions comprising a stowed position in which the third jib structural element (33) is folded and pulled towards the second jib structural element (32), and a deployed position in which the third structural element jib (33) is unfolded and extends in alignment the second jib structural element (32), wherein a position detection step implements a detection of the actual position of the third jib structural element (33) among its two positions, and wherein the selection step implements the automated selection of the preferential load curve according to the actual inclinations of said two jib structural elements (31, 32) and the actual position of the third jib structural element (33), said preferential load curve being selected from among the plurality of load curves calculated beforehand for several inclinations of said two jib structural elements (31, 32) and for the two positions of the third jib structural element (33).

5. The drive method according to claim 4, wherein the position detection step is implemented by means of a detector (63) selected from: - an inclinometer mounted on the third jib structural element (33), or - a position or proximity sensor which is mounted on the second jib structural element (32) or on the third jib structural element (33) to detect the presence / absence of the third jib structural element (33) in one of the two positions.

6. The drive method according to any one of the preceding claims, comprising a height measurement step implementing a measurement of an actual height of the luffing jib (3) with respect to a ground in the work configuration, and wherein the selection step implements the automated selection of the preferential load curve according to the actual inclination of the jib structural element (61; 62) and the actual height of the luffing jib (3), said preferential load curve being selected from among the plurality of load curves calculated beforehand for several inclinations of said jib structural element (61; 62) and for several heights of the luffing jib (3).

7. The drive method according to claim 6, wherein the mast (2) is a telescopic mast comprising mast structural elements (21, 22) telescopically mounted, and the height measurement step is performed by means of a sensor which measures a telescoping level between the mast structural elements (21, 22).

8. The drive method according to claim 1, wherein the selection step is implemented by a control / command system (5), said control / command system (5) being connected to the memory (50) storing the plurality of load curves and to maneuvering actuators (81, 82) of the crane (1) to perform the drive step.

9. A crane (1) comprising a mast (2) supporting a luffing jib (3) comprising at least one jib structural element (31; 32), said crane (1) further comprising: - an inclinometer (61; 62) mounted on said jib structural element (32; 32) for a measurement of the actual inclination of the jib structural element (31; 32) with respect to a reference axis in a work configuration; - a control / command system (5) connected to the inclinometer (61; 62); said crane (1) being characterized in that the control / command system (5) is connected to a memory (50) storing a plurality of load curves calculated beforehand for several inclinations of said jib structural element (31; 32); and in that said control / command system (5) is configured to implement an automated selection of a preferential load curve according to the actual inclination of said jib structural element (31; 32), said preferential load curve being selected from among the plurality of load curves stored in said memory (50); and said control / command system (5) is connected to maneuvering actuators (81, 82) and is configured to drive maneuvers of lifting and moving a load along the luffing jib (3) in the work configuration of the crane (1), by applying said preferential load curve.

10. The crane (1) according to claim 9, wherein the luffing jib (3) is foldable and comprises at least two jib structural elements (31, 32) articulated with each other and on which are mounted respective inclinometers (61, 62) for measuring the actual inclinations of the two jib structural elements (31, 32) with respect to the reference axis in the work configuration, and wherein the control / command system (5) is configured to implement the automated selection of the preferential load curve according to the actual inclinations of said two jib structural elements (31, 32), said preferential load curve being selected from among the plurality of load curves calculated beforehand for several inclinations of said two jib structural elements (31, 32).

11. The crane (1) according to claim 10, wherein the two jib structural elements (31, 32) comprise a first jib structural element (31), forming a jib foot, which is articulated on the mast (2), and a second jib structural element (32) articulated on the first jib structural element (31).

12. The crane (1) according to claim 11, wherein the luffing jib (3) comprises a third jib structural element (33), forming a jib tip, which is articulated on the second jib structural element (32) and which is movable between two positions comprising a stowed position in which the third jib structural element (33) is folded and pulled towards the second jib structural element (32), and a deployed position in which the third structural element jib (33) is unfolded and extends in alignment the second jib structural element (32), wherein a detector (63) is configured for a detection of an actual position of the third jib structural element (33) among its two positions, and wherein the control / command system (5) is configured to implement the automated selection of the preferential load curve according to the actual inclinations of said two jib structural elements (31, 32) and the actual position of the third jib structural element (33), said preferential load curve being selected from among the plurality of load curves calculated beforehand for several inclinations of said two jib structural elements (31, 32) and for the two positions of the third jib structural element (33).

13. The crane (1) according to claim 12, wherein the detector (63) is selected from: - an inclinometer mounted on the third jib structural element (33), or - a position or proximity sensor which is mounted on the second jib structural element (32) or on the third jib structural element (33) to detect the presence / absence of the third jib structural element (33) in one of the two positions.

14. The crane (1) according to any one of the claims 9 to 13, comprising a height measurement device for implementing a measurement of an actual height of the luffing jib (3) with respect to a ground in the work configuration, and wherein the control / command system (5) is configured to implement the automated selection of the preferential load curve according to the actual inclination of the jib structural element (61; 62) and the actual height of the luffing jib (3), said preferential load curve being selected from among the plurality of load curves calculated beforehand for several inclinations of said jib structural element (61; 62) and for several heights of the luffing jib (3).

15. The crane (1) according to claim 14, wherein the mast (2) is a telescopic mast comprising mast structural elements (21, 22) telescopically mounted, and the height measurement device comprises a sensor which measures a telescoping level between the mast structural elements (21, 22).