FR2587320A1 - METHOD FOR CONTROLLING THE STABILITY OF A MOBILE CRANE. - Google Patents

Abstract

THIS PROCESS IS IMPLEMENTED ON A CRANE INCLUDING A COLUMN5 ARTICULATED AROUND A VERTICAL AXIS ON THE CHASSIS3 OF A VEHICLE AND ARMS6, 8 ARTICULATED ON ONE ON THE OTHERS AROUND HORIZONTAL AXLES7, 9, THE LAST ARM8 BEING EQUIPPED OF A TELESCOPIC ARROW 10. THE PROCEDURE CONSISTS OF EQUIPPING THE CHASSIS OF THE VEHICLE OR THE BASE OF COLUMN5 WITH TWO TILT DETECTORS D1, D2 WHOSE CELUID2 CORRESPONDS TO A MAXIMUM TOLERABLE STATE BEFORE THE INSTABILITY AND OF WHICH CELUID1 MATCHES A LOWER THRESHOLD. THE PROCESSING OF INFORMATION PROVIDED BY PARD1 ALLOWS THE PROHIBITION OF CERTAIN MOVEMENTS AND THE CONTINUATION OF OTHER MOVEMENTS THE OPPORTUNITY OF WHICH IS INVALIDATED IF THE THRESHOLD2 IS REACHED.

Description

I

  METHOD FOR CONTROLLING THE STABILITY OF A MOBILE CRANE

  The present invention relates to a method of controlling the stability of a mobile crane comprising a column whose lower end is pivotally mounted about a vertical axis on the chassis of a vehicle, and at the upper end of which is articulated around a horizontal axis, an arm at the other end of which at least one arm can be articulated, the end arm being able to be equipped with an arrow

  telescopic provided with means for hooking the load.

  Figure 1 of the accompanying schematic drawing shows a vehicle 2 whose chassis 3 shown schematically by two beams is equipped with a crane 4 comprising a column 5 capable of being rotated in two opposite directions about a vertical axis, an arm 6 articulated around a horizontal axis 7 on the column 5, an arm 8 articulated around a horizontal axis 9 on the arm 6, the arm 8 being equipped with an arm

  telescopic 10, the end of which is provided with a hook 12 for hooking

charge of a charge.

  This crane comprises means for carrying out the various movements independently of each other, allowing rotations H and G of the column 5 in two opposite directions. A cylinder 13 allows the modification of the angle formed by the arm 6 and the column 5 in a direction of opening of the angle during movement A and closing of the angle during movement B. A cylinder 14 allows modification of the angle formed by the arms 6 and 8 in a direction of opening of the angle during movement C and closing of the angle during movement D. Finally, the jack 15 ensures the movement of the telescopic boom in a direction of exit thereof during movement E and re-entry thereof during movement F. In addition to the natural supports of the vehicle at its wheels T, U, V, W, the stability, in period d crane use can be increased by adding additional supports such as crutches X, Y. The set of ground supports T, U, V, W, X, Y in the case shown in the drawing, defines a polygon of lift on which the mass of the assembly is applied and forms the resistant moment opposing overturning under the request of a couple whose the moment is constituted by the product P x L in which P is the weight PI of the part of the cantilever lifting device, increased by the weight P2 of the load and L is the distance between the center of gravity of these two masses and the point of application of the resulting torque on

the lift polygon.

  This couple generates stresses, and consequently deformations varying the angle of the plane of the support polygon.

  relative to a generally horizontal reference plane.

  The object of the invention is to provide a control method

  the stability of a crane aimed at prohibiting all operations which

  should exceed a predetermined maximum superelevation value beyond

  from which the stability of the whole would become very precarious.

  This critical state can result, on the one hand, from operations carried out in a vertical plane when modifying the distance between the point of application of the load and the pivot axis of the column on the chassis, but also of the angular position of the column on the

  chassis, depending on the constitution of the support polygon, i.e.

  say the shape of it and the supports it understands.

  This is how Figure 2 schematically, in top view,

  the lift polygon of the vehicle in figure I shows which

  There could be Z zones in which the stability could be reduced more. The method according to the invention consists in equipping the chassis of the vehicle near the center of gravity of the support polygon and / or of column 5, or the base

  the column of a two-threshold tilt detector, or two detectors

  slope superiors DI, D2 at a threshold, the lower threshold of which corresponds to a position close to a state of instability and the upper threshold of which corresponds to a maximum tolerable state before instability, to arrange the control means of the various movements in such a way that it is not possible to simultaneously perform the rotation G, H of the column and a movement A, B, C, D, E, of the arms in a vertical plane, to be detected if the reaching of the first threshold DI is obtained by a rotational movement G, H of column 5 in one direction or in

  the other, or by a movement A, B, C, D, E, of the arms in a vertical plane

  cal, to prohibit, upon reaching the first DI threshold, the exit

  E of the arrow 10 of the telescope, then in a predetermined manner but arbi-

  milk, the rotational movements A, C in one direction of the arms relative to the column and of the arms between them then, if the second threshold D2 is reached by continuing authorized movements, 5. to carry out an inversion of the authorizations B, D and prohibitions

  A, C movements of the arms in a vertical plane.

  The detection of the first DI threshold makes it possible to know the monitoring

  imminent instability, the processing of this information

  mation to prohibit the company or the continuation of operations

  which, in any case, would aggravate the situation of instability.

  Reaching this first threshold also makes it possible to arbitrarily ban the company or the pursuit of certain operations. If the authorized operations lead to reaching the second superelevation threshold D2, the operations known to be aggravating remain prohibited, while the passage from the first threshold to the second threshold allows

  to determine, irrevocably, the sequence of operations to be carried out.

  Obtaining a signal indicating the direction of rotation of

  the column is particularly interesting because it ensures a different

  ciation among the possible movements of the apparatus between those which affect the moment of overturning and those which have a

  impact on the variable stability zone.

  Each direction of rotation of the column is determined in a simple way by an opening and closing contactor placed on each

control unit.

  In any case, the invention will be well understood using the

  description which follows, with reference to the appended schematic drawing representing

  so much. by way of nonlimiting examples, two positions of the crane during two operating phases, this type of crane having been chosen on purpose for its complexity: FIG. 3 is a very schematic view of the crane in the case where the movements A, C increase the reach of the crane Figure 4 is a view of the crane in the case where the movements

  A, C decrease the range of the crane.

  On the equipment shown in Figures 3 and 4, the normal operating movements are A, B, C, D, E, F, G, H, movements J and K only used for the static positioning of the chassis during the output of the crutches X and Y. As indicated previously, it is possible to identify two families of movements contained in orthogonal planes, namely movements G, H in a horizontal plane and movements A,

  B, C, D, E, F in a vertical plane.

  The different movements produce the following effects E always increases the range of the crane and, consequently, the torque, F always decreases the range of the crane and, consequently, the torque, 10. A and C increase or decrease the range according to that one is in one or other of the situations of figure 3 and figure 4, B and D decrease or increase the range according to whether one is in one or the other of situations of figure 3 and FIG. 4, G which can bring in or out the plane of the overturning torque of a zone with reduced stability,

  H has the same effects as G in reverse.

  It is important to note that G and H can leave the plane of the overturning torque of a zone of reduced stability then, by

  their pursuit, re-reach this area.

  In the embodiment shown in the drawing, the crane is equipped, at its base, with two superelevation detectors DI and D2, the value D2 corresponding to a maximum tolerable value of superelevation before the instability and the value Dl corresponding at a value

  more acceptable superelevation, the DI superelevation value corresponding to

  lay, for example, 95% of the cant value of D2.

  During the operation of the crane, reaching the DI threshold can result either from one of the movements A, B, C, D, E, or from one of the

  rotations G or H of column 5 on the chassis.

  Knowing that we detect the rotations G and H, it will be possible,

  when the threshold Dl is reached, to determine if this results from a rotation

  tion G in which case the information obtained will be DI Gm, of rotation H in which case the information obtained will be DI Hm, or of a movement

  A, B, C, D, E, in which case the information obtained will be DI.

  The distinction between these different events is made possible.

  ble because it is not possible to control a rotation G or H simultaneously with a movement A, B, C, D, E. - If the first threshold DI is reached during a rotation of column 5 in direction G, the electronic processing system, either with microprocessors or combinatorics, receives the information DI Gm. This system prohibits the continuation of the rotation G which caused the DI to be reached, as well as the movement E of exit from the telescopic boom which is always aggravating.

  In a predetermined and arbitrary manner, the system also prohibits

  movements A and C. As a result, movements B, D,

F and H are allowed.

  F can always be undertaken because it is aggravating.

  10. H can be undertaken since it is the reverse of the movement G which allowed the DI threshold to be reached. The consequences of H can be known, since its execution prohibits that of movements B and D. Although H systematically worsens the situation since it is the reverse of G, it can allow reaching, by its pursuit beyond

  from the normal DO stability state a new DI threshold, the information should

  nant, in this case there, Dl Hm whose treatment is explained below.

  If a B or D movement is undertaken, it is possible to assess the consequences. If this movement is aggravating, it erases

  the DI signal and the system returns to its normal DO state.

  If B or D is aggravating, the second threshold will be reached, this

  information being provided by the detector D2 which will prohibit movement

  elements B and D, prohibit movement H, maintain movement G prohibited and re-authorize movements A and C. A return to normal situation is therefore possible by acting on movements A, C or F,

  the latter always remaining authorized because it is deteriorating.

  It is interesting to note that, while declining, the movement

  H is prohibited. Indeed, this movement H brings the stability back to the threshold Dl, then to the threshold DO then, if continued, can, by changing the zone, bring the crane to the first instability threshold DI Hm. But, insofar as DI would be reached by a movement B or D, if movement H was authorized when the threshold D2 was reached, the change

  could lead to an uncontrolled tilt situation.

  The execution of the reverse A or C movements of B or D, which led to reaching the threshold D2 necessarily brings back the crane

  at least at the DI threshold, or even, depending on the kinematics of the crane, at the

  normal ation DO. If movements A, C or F bring the device back only to the first threshold DI, the normal situation DO is returned by rotation

258.7320

H from column 5.

  - If the DI threshold is reached by a rotation H of the column, the DI Hm information is: supplied to the logic system. The logical system prohibits movements H, E, A and C and authorizes movements G, B, Det F. The solutions to the situations arising therefrom are identical to those resulting from the information DI Gm, developed previously with inversion of the movements H and G. - The threshold Dl can also be reached by movement of the

  arms 6, 8 and 10 in a vertical plane.

  * If the threshold DI is reached by a movement A or C, which is only possible in the case shown in Figure 3, reaching this threshold prohibits movements A, C and E, movements B, D,

F, G and H remain authorized.

15. F is always deteriorating,

  B or D is deteriorating since these are reverse movements

  its from A and C having led to the DI situation, G is either aggravating or deteriorating,

  It is either aggravating or aggravating.

  If you execute the H movement and it is aggravating, the device

  will reach threshold D2. Reaching this threshold results in the inter-

  diction of E, B, D, G, H, however, this situation having been reached by a movement H, the control system will receive the signal D2 Hm. By its processing, this signal will re-prohibit A, C, by reversing the prohibition of B, D resulting from D2. Similarly, this information will re-authorize G. The process is identical with inversion between movements G and H if the second threshold is reached by a movement G. * If the threshold DI is reached by a movement B or D, which

  is possible only in the situation shown in figure 4, the

  shade of this threshold prohibits movements A, C and E, movements

  B, D, F, G and H remain authorized.

  F is always aggravating, B or D are aggravating, but authorized, 35. G is either aggravating or aggravating,

  It is either aggravating or aggravating.

  If movements G and H are performed and they are aggravated

  the threshold D2 will be reached and we will be in the same situation as that previously envisaged by supplying a signal D2 Gm

or D2 Hm.

  If the aggravating but authorized movements B or D are undertaken or continued, the threshold D2 will be reached which will cause the prohibition of movements E, B, D, G, H, and the authorization of movements A and C. If after the occurrence of DI, but before reaching the threshold D2 by a movement B or D, movement B or D is interrupted, the system finds itself in an already analyzed situation of Dl without other information, resulting in the prohibition of E, A and C and the authorization of H, G, B, D and F. The execution of G or H will have the consequences already seen in

this eventuality.

  The execution of B or D will lead to the reaching of the threshold D2 resulting in the prohibition of E, B, D, G, H, and the authorization of A

  and C, inverse of B and D by which the second threshold was reached.

  The devices targeted by the process according to the invention are mature, using either hydraulic circuits with manual or electrical control,

  either fully electric circuits.

  Prohibitions can be easily obtained by means known to those skilled in the art and generally used to cut such circuits with return to the initial position in the absence

cutoff signal.

  The signals delivered by the tilt detector, and by the

  rotational movements G and H are delayed both when they occur

  tion of their disappearance, in order to ensure a well-established situation

before dealing with them logically.

  According to another characteristic of the invention, the apparatus comprises

  takes a third stability detector reacting to a threshold lower than that of the other two detectors, controlling an audible and / or optical warning device, informing the operator of the imminent occurrence of the first DI threshold and enabling him to avoid being in one of the situations mentioned above which includes prohibitions on

movements.

  In addition, the device is equipped with a synoptic table informing the operator of the equilibrium situation of the assembly, and indicating to him

  prohibited and authorized operations at all times.

  This process is very interesting to implement in combination with

  sound with a system to oppose the overload of a lifting device. In this case, a complete system is obtained which controls the state of charge and stability of the carrier vehicle-apparatus assembly.

lifting.

  It goes without saying that the invention is not limited to the sole embodiment of this method, described above by way of example.

  on the contrary, it embraces all of its variant embodiments.

  It is thus in particular that it would be possible, after reaching the first threshold DI, to authorize the movements A, C of pivoting of the arms in a vertical plane opposite to those B, D which were authorized

  in the description above, these movements remaining reversed at

  during the course of each subsequent phase of the process.

Claims (6)

  1. - Method for controlling the stability of a mobile crane   taking a column whose lower end is pivotally mounted about a vertical axis on the chassis of a vehicle, and at the upper end of which is articulated, around a horizontal axis, an arm at the other end which can be articulated around a horizontal axis at least one other arm, the end arm may include a telescopic arm whose free end is equipped with means for hooking the load, the telescope may be located on the first articulated arm, this crane comprising means for driving the column in rotation in the chassis in two opposite directions, as well as means, independent of each other, making it possible to vary the different angles formed by the column and the arms, as well as the position of the telescopic boom, characterized in that it consists:  15. to equip the vehicle chassis near the center of gravity of the lift polygon and / or the column (5), or the base   the column of a two-threshold tilt detector, or two detectors   slope superiors (Dl, D2) at a threshold, whose lower threshold corresponds to a position close to a state of instability and whose upper threshold corresponds to a maximum tolerable state before instability, to arrange the control means different movements in such a way that it is not possible to simultaneously perform the rotation (G, H) of the column and a movement (A, B, C, D, E) of the arms in a vertical plane, 25. to detect whether the achievement of the first threshold (Dl) is obtained by a rotational movement (G, H) of the column (5) in one direction or the other, or by a movement (A, B, C, D, E) arms in a vertical plane, to prevent, when reaching the first threshold (Di), the exit (E) of the arrow (10) of the telescope, then in a predetermined but arbitrary manner, the movements of rotation (A, C) in one direction of the arms relative to the column and the arms between them then, if the second threshold (D2) is reached by continuing the authorized movements, to carry out an inversion authorizations (B, D) and prohibitions   (A, C) movements of the arms in a vertical plane.   2. - Method according to claim 1, characterized in that, in so far as the first instability threshold (D1) is reached by rotation of the column (5) in one direction (G), it consists in prohibiting the pursuit rotation in this direction, the output (E) of the telescopic boom (10), and in a predetermined and arbitrary manner the rotational movements (A, C) in one direction of the arms relative to the column (5) and arms between them, the other movements (B, D, F, H) remaining authorized then, if these movements cause the reaching of the second threshold, to carry out an inversion of the authorizations (B, D) and prohibitions (A, C) of arm movements in a vertical plane and, in addition, the prohibition of the rotation (H) of the column in the opposite direction of   the one that caused the first threshold to be reached.   3. - Method according to claim 1, characterized in that, insofar as the first instability threshold (D1) is reached by movement of the arms in a vertical plane, then o the second threshold (D2) is reached by rotation of the column in one direction (G), reaching this second threshold prohibits rotation of the column in the direction that caused the second threshold to be reached and authorization to   the rotation (H) of the column in the opposite direction.   4. - Method according to any one of claims 1 to   3, characterized in that the signals delivered by the detector (DI, D2)   and by the rotational movements of the column are tempo-   laughed at both when they appeared and when they disappeared, in order to   ensure a well-established situation before dealing with them logically.   5. - Method according to any one of claims 1 to   4, characterized in that the slope detector comprises a third threshold corresponding to a superelevation situation situated below the first, _-- reaching - of - this-third threshold actuating an audible and / or optical warning device informing the operator of the imminent occurrence of the first cant threshold.   6. - Method according to any one of claims 1 to   , characterized in that it is used on an equipped crane, in   in addition, a load lifting limitation device.