The present invention relates to a device for locking an object hanging from a cable. The invention makes it possible to position the object at different positions along the cable. The invention finds particular utility in the field of sonar detection and more specifically for airborne sonar often called "dipping sonar" or "dipping sonar" in Anglo-Saxon literature. This particular field consists of immersing a sonar antenna from a helicopter or a drone to a desired depth.

[0002] In the context of anti-submarine warfare activities, in order to be able to detect submarines submerged in a given area, recourse is generally had to the use of sonars, in particular active sonars. In this context, the deployment of sonars from aerial platforms, helicopters or drones, proves to be particularly effective because such platforms have great mobility compared to submarines.

More specifically, helicopters are used to implement sonar transmitters and receivers connected by a cable to their platform, in other words to the helicopter. We then speak of "dipped sonars". Subsequently, the sub-assembly submerged and connected by the cable is called antenna. It includes the actual sonar transmitters and receivers and possibly electronic equipment associated with the transmitters and receivers. It may also include environment sensors.

More generally, the invention relates to any object that one wishes to hang from a wearer, whether in the air or in the water.

[0005] To return to dipped sonars, in a known manner, the launching from the platform, the immersion control as well as the recovery on board of these antennas are carried out by means of a winch located inside the helicopter. The cable is fixed to the antenna and the adjustment of the depth of immersion is achieved by winding or unwinding the cable from the helicopter.

[0006] During the descent and the ascent of the antenna by means of the winch, the cable generates significant drag in the water. This drag increases with the depth reached by the antenna due to the length of cable unwound. The rate of descent and ascent of the antenna is thus limited by the drag generated by the movement of the cable. The greater the depth, the more the speed must be reduced in descent because the antenna is dragged down only by its reduced weight of its own drag and that of the cable. On ascent, the winch must exert on the cable a force equal to the weight of the antenna increased by the overall drag. It would be possible to provide a winch capable of withstanding significant drag. The cable must be sized to withstand the pulling force exerted by the winch.

[0007] In order to limit the drag of the cable during its movements in the water, the applicant has explored the possibility of placing the winch inside the antenna. The problem then arises of locking the antenna on the cable. The winch disposed inside the antenna can easily perform this function by means of a brake making it possible to block the actuator of the winch. This brake can be active, in other words, it is activated as long as the antenna is stationary. Alternatively, the brake can be passive. In other words, the brake is activated when the winch is in motion. In both cases, active brake or passive brake, the energy expenditure of maneuvering the brake extends over a significant period, during the phase of immobility of the antenna for the active brake or during the phases of maneuvering of the winch for the passive brake.

The invention aims to reduce the energy expenditure of the brake by taking advantage of the weight of the antenna. The invention can be implemented even in the absence of a winch in the antenna, for example to cause an antenna to slide and more generally an object which it is desired to position along a cable.

[0009] To this end, the subject of the invention is a device for locking an object hanging from a cable, the device comprising a cable and a clamp, the cable passing through the clamp extending along a substantially vertical axis, the gripper comprising: a fixed part connected to the object, at least two movable jaws, a

first actuator and a second actuator, the two jaws being able to move in translation relative to each other in a direction perpendicular to the axis of the cable, the two jaws coming into contact with the cable to immobilize the cable by clamping in a closed position and moving away from the cable in an open position, the fixed part having as many inclined surfaces as there are jaws, the inclined surfaces being inclined with respect to the axis of the cable, so as to approach the axis of the cable upwards, each of the jaws being configured to slide along one of the inclined surfaces, the sliding allowing the jaws to pass from the open position to the closed position, the gripper further comprising elastic elements configured to move the jaws apart from the cable,the first actuator being configured to move the jaws upwards, to make them slide along their respective inclined surface and to allow the clamp to close, the second actuator being configured to pull the cable relative to the fixed part downwards and allow the clamp to open.

[0010] The elastic elements are advantageously arranged between each of the jaws and tend to separate the jaws from each other.

[0011] The jaws are advantageously regularly distributed radially around the axis of the cable and the movement of the jaws is symmetrical with respect to the axis of the cable.

[0012] The fixed part advantageously comprises as many grooves as there are jaws, each jaw sliding in one of the grooves, the inclined surface associated with the jaw in question forming a bottom of the groove, the groove being configured to provide lateral guidance of the jaw in question in a radial plane around the axis of the cable.

In a radial plane around the axis of the cable, each jaw advantageously has a section substantially in the shape of a rectangular trapezium, a first side of which is bordered by two right angles and is parallel to the axis of the cable and belongs to a first face. of the jaw in question, the first face being configured to come into pressure on the cable and of which a second side, opposite the first side, belongs to a second face of the jaw in question, the second face coming into contact with an inclined surface.

[0014] The inclined surfaces are advantageously inclined at an angle a with respect to the axis of the cable, a coefficient of friction f2 being defined between the jaws and the cable and the coefficient of friction f2 is greater than or equal to the tangent of the angle a so as to make the clamp self-locking under the effect of the weight of the object.

[0015] A coefficient of friction f1 is advantageously defined between each jaw and the corresponding inclined surface, the coefficient of friction f1 being substantially zero.

[0016] Alternatively, the coefficient of friction f2 is greater than or equal to the tangent of the sum of the angle a and the arc-tangent f1 so as to make the gripper self-locking under the effect of the weight of the object.

[0017] The second actuator is advantageously a winch arranged inside the object and configured to wind and unwind the cable.

[0018]Each jaw advantageously comprises a first face coming into pressure on the cable, the first face having a shape complementary to that of the cable.

The fixed part can have a degree of freedom in translation along the axis relative to the object.

The fixed part can be connected to the object by means of a second elastic element.

[0021] The second elastic element is advantageously configured to allow flexibility of the fixed part with respect to the object in translation along the axis and also according to the other degrees of freedom.

The second elastic element is advantageously configured to transform a major part of the kinetic energy of the object into potential energy in the deformation of the elastic element.

[0023] The second elastic element advantageously has properties

damping to dissipate the potential energy resulting from the kinetic energy of the object.

The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, description illustrated by the attached drawing in which:

Figures 1a and 1b show different carriers each equipped with a dipped sonar;

[0026] Figure 2 shows a first alternative embodiment of an antenna of the dipped sonar of Figures 1a and 1b;

Figures 3a and 3b show a second alternative embodiment of an antenna of the dipped sonar of Figures 1a and 1b;

[0028] Figures 4a, 4b, 4c and 4d describe the principle of operation of a clamp entering a locking device according to the invention;

[0029] Figures 5 and 6 illustrate the parameters to be chosen to obtain a self-locking clamp;

Figure 7 shows the clamp in partial section in a plane perpendicular to the axis of the cable supporting the antenna;

[0031] Figures 8a, 8b and 8c illustrate a clamp variant.

[0032] For the sake of clarity, the same elements will bear the same references in the various figures.

The detailed description of the invention is made in relation to a dipped sonar and more specifically to a sonar antenna hanging from a cable attached to a carrier. The invention is not limited to a sonar and can be implemented for any object hanging from a cable capable of sliding along the cable.

[0034] Figure 1a shows a drone 10 hovering above the water, the surface of which bears the mark 11. The drone 10 is equipped with a hardened active sonar comprising an antenna 12 attached to the drone 10 by a cable 14. This type of sonar notably enables the detection and classification of underwater objects. FIG. 1b represents a helicopter 16 also equipped with a dipped active sonar comprising the antenna 12 attached to the helicopter 16 by the cable 14. Any type of carrier capable of positioning itself above the water can be equipped of a dipped active sonar. The wearer is able to lower the antenna to a desired depth of immersion, to control an acoustic detection phase and to raise the antenna in order to complete its mission or in order to carry out other missions.

[0035] Figure 2 shows a first antenna embodiment 20 of a dipped active sonar. The antenna 20 is equipped with acoustic transmitters 22, acoustic receivers 24 as well as a motorized winch 26. The winch 26 makes it possible to wind and unwind the cable 14. A free end 27 of the cable 14 makes it possible to hang the antenna 20 to the carrier such as the drone 10 or the helicopter 16. The antenna 20 extends along an axis 28 which is vertical when the antenna 20 is hung by the cable 14 and is only subjected to gravity. The antenna 20 has a shape substantially of revolution around the axis 28. The acoustic transmitters 22 and the acoustic receivers 24 are arranged radially around the axis 28.

[0036] The acoustic transmitters 22 and the acoustic receivers 24 can be fixed to a box 29 of the antenna 20. The acoustic emitters 22 and the acoustic receivers 24 can be arranged in separate zones of the antenna 20, the zones being superimposed one above the other as represented in FIG. 2. Alternatively, the zones can be nested as for example described in the patent application published under the number WO2015/092066 and filed in the name of the applicant.

The winch 26 is motorized by means of an actuator 30. More specifically, the actuator 30 makes it possible to rotate a reel 32 on which the cable 14 is wound. The actuator 30 can be an electric or hydraulic motor or more generally using any form of energy able to operate in a confined space without air renewal. It is advantageously located inside the reel 32 in order to free up space in the antenna 20. The cable 14, on its unwound part, extends along the vertical axis 28. The antenna 20 hangs under the effect of gravity. In Figure 2, the reel 32 rotates around a horizontal axis 34. Alternatively, the cable 14 can be wound around a reel with a vertical axis. A winding mechanism makes it possible to store the cable 14 on the reel 32. The winding mechanism ensures alternate translation of a cable guide along the axis of the reel in order to store the cable 14 in successive layers on the reel 32. In the case of a reel with a vertical axis, the reel can be stationary and the winding mechanism then rotates around the reel in addition to its translation. Such mechanisms exist in particular in fishing reels. Alternatively, the reel can turn around its axis and the guide of the winding mechanism only moves in translation relative to a housing 29 of the antenna 20. Such mechanisms exist in particular in fishing reels. Alternatively, the reel can turn around its axis and the guide of the winding mechanism only moves in translation relative to a housing 29 of the antenna 20. Such mechanisms exist in particular in fishing reels. Alternatively, the reel can turn around its axis and the guide of the winding mechanism only moves in translation relative to a housing 29 of the antenna 20.

The winch 26 formed of the reel 32 and the actuator 30 is arranged inside the antenna 20, for example in an internal volume 36 located between the acoustic receivers 24.

The antenna 20 also comprises electronic modules 38 allowing in particular the generation of the acoustic signals emitted by the transmitters 22, the processing of the acoustic signals received by the receivers 24 and the control of the actuator 30.

The electrical energy necessary for the operation of all the components of the antenna 20 can come from the carrier and be conveyed by the cable 14. However, this solution requires increasing the section of the cable 14 to be able to convey any the energy needed. In particular, the supply of acoustic transmitters requires a high instantaneous power which can be of the order of several kilowatts. Since the cable 14 can exceed several hundred meters in length, it is then necessary to provide a sufficiently large section of cable to limit the effects of ohmic losses along the cable 14. This tends to increase the dimensions of the reel 32 which must be able to accommodate the cable 14 in almost its entire length. In addition, during the acoustic emission phases,

[0041] To limit the periods of high power transfer in the cable 14, it is advantageous that the antenna 20 is equipped with a battery 40 advantageously arranged in a lower part of the antenna 20 or at least under the volume 36 containing the winch 26 in order to allow the antenna to maintain a better vertical orientation, in particular during the descent when it is hung by the cable 14. The battery 40 can be intended to smooth the transfer of electrical energy in the cable 14, which makes it possible to reduce the section of the electrical conductors of the cable 14. To this end, the battery 40 can supply the acoustic transmitters 22 which usually emit at high power during a small fraction of the duration of a mission. It is also advantageous to completely dispense with energy transfer in the cable 14. The battery 40 then supplies all the electrical loads of the antenna, such as in particular the winch 26, the electronic modules 38, the transmitters 22 and acoustic receivers 24. For recharging the battery 40, the antenna comprises independent recharging means of the cable 14, such as for example a specific connector or a contactless recharging zone 42, for example by induction. The recharging of the battery 40 can be done on board the carrier 10 or 16 by connecting the specific connector or by placing the zone 42 close to a dedicated inductor. the antenna comprises recharging means independent of the cable 14, such as for example a specific connector or a contactless recharging zone 42, for example by induction. The recharging of the battery 40 can be done on board the carrier 10 or 16 by connecting the specific connector or by placing the zone 42 close to a dedicated inductor. the antenna comprises recharging means independent of the cable 14, such as for example a specific connector or a contactless recharging zone 42, for example by induction. The recharging of the battery 40 can be done on board the carrier 10 or 16 by connecting the specific connector or by placing the zone 42 close to a dedicated inductor.

[0042] L’antenne 20 peut également comprendre des capteurs d’environnement comme un sondeur 44 permettant de déterminer la distance de l’antenne 20 au fond et un capteur de température 46 permettant de mesurer l’évolution de la température de l’eau en fonction de la profondeur atteinte par l’antenne 20. En effet, la propagation des ondes sonores dans l’eau est fonction de l’évolution de la température de l’eau. Ces capteurs peuvent également être alimentés par la batterie 40.

Figures 3a and 3b show a second antenna embodiment 50 of a dipped active sonar according to the invention. In this variant during sonar reception, the acoustic receivers 24, possibly placed on arms, are deployed at a distance from the housing 29 of the antenna 50. On the other hand, when the winch 26 is operated, the acoustic receivers 24 are placed against the housing 29 in order to limit the drag of the antenna 50 during the descent and the ascent of the antenna 50 in the water. This type of deployable antenna was developed in the past by the applicant. In this type of antenna, the deployment of the acoustic receivers is carried out by means of an electromechanical mechanism placed in the antenna. This mechanism includes an electric motor moving arms supporting the acoustic receivers. The motor is activated both during deployment and during folding of the arms. This mechanism is heavy and bulky.

It is possible to keep in the antenna such an electromechanical arm maneuver mechanism supporting the acoustic receivers 24. Alternatively, the second variant makes it possible to dispense with this mechanism.

The antenna 50 comprises deployable arms 52 on which the acoustic receivers 24 are arranged. The arms 52 are advantageously distributed evenly around the axis 28 in order to ensure complete acoustic detection around the axis 28 Figure 3a partially shows the antenna 50 in which the arms 52 are folded against the housing 29. Figure 3b also partially shows the antenna 50 in which the arms 52 are deployed at a distance from the housing 29. The arms 52 are articulated with respect to the housing 29 and with respect to a body 54 forming a cover in the form of a washer and mobile in translation with respect to the housing 29 along the axis 28. The body 54 is for example of revolution around the axis 28 and the cable 14 passes through body 54 through the hole in the washer.

[0046] This double articulation allows the arms 52 to move away from or approach the housing 29 when the body 54 moves. More specifically, in the position of the body 54 shown in FIG. 3a, the arms 52 are folded against housing 29 and in the position of the body 54 shown in Figure 3b, the arms 52 are deployed away from the housing 29.

The arms 52 can be articulated directly on the housing 29 and on the body 54 by means of pivot links. Once deployed, the arms 52 extend horizontally or inclined with respect to the axis 28. The kinematics of this type of mechanism is very simple. It is used in particular in sonar buoys where the wearer floats on the surface of the water. However, this orientation of the arms can degrade the acoustic detection when the wearer is a drone or a helicopter. Indeed, in this orientation, the acoustic receivers 24 are disturbed by the noise generated by the wearer. It may therefore be preferable to provide a vertical orientation of the arms 52 when they are deployed. In other words, it may be desirable to keep the arms parallel to the axis 28 during the translation of the body 54. To do this,

via a deformable parallelogram. More specifically, two bars 56 and 58 having parallel sections are articulated on the one hand on an arm 52, respectively by means of links 60 and 62, and on the other hand on the housing 29, respectively by means of links 64 and 66 One of the bars, the bar 58 in the example shown, is articulated to the body 54 by means of the link 68 at a point distant from its articulation to the arm 52 and from its articulation to the housing 29. Thus, when the body 54 is moves in translation, the bar 58 pivots around its articulation to the casing 29 and drives the arm 52. The bar 56 is driven by the arm 52 and also pivots with respect to the casing 29. During this movement, the orientation of the arm 52 relative to the housing 29 does not vary. In the example shown,

The movement of the body 54 in translation relative to the housing 29 can be achieved by means of an electromechanical actuator directly ensuring this movement. The actuator is for example formed of a linear cylinder whose body is fixed to the housing 29 and whose rod, moving in translation with respect to the body of the cylinder, is fixed to the body 54. Reverse mounting is also possible.

Advantageously, it is possible to dispense with an actuator between the housing 29 and the body 54 by using the forces of gravity acting on the housing 29 and on the body 54. Indeed, the housing 29 can contain heavy components that can be used to deploy the arms 52. To do this, the body 54 is provided with a clamp 70 configured to clamp the cable 14 and immobilize it relative to the body 54.

In the open position of the clamp 70, the cable 14 is free relative to the body 54 and its weight, associated with that of the arms 52 via the joint 68, drives the body 54 downwards, c 'that is to say towards the housing 29. In this position, the arms 52 are also driven downwards, that is to say in the folded position against the housing 29. This position, clamp open, is shown on the Figure 3a. [0051] In the closed position of the clamp 70 the cable 14 is immobilized with respect to the body 54. In this position, it is possible to operate the winch 26 so as to unwind the cable and thus allow the housing 29 and the equipment which are fixed to descend relative to the body 54 under the effect of gravity. This relative movement of the body 54 relative to the housing 29 causes the deployment of the arms 52 to reach the position of FIG. 3b. This is possible if the arms 52, and if necessary the bars 56 and 58, are lighter than the housing 29 and all the components attached to it. This condition is generally easily met due to the presence of heavy components in the housing 29, in particular the battery 40 and the winch 26. The operation of the winch 26 to unwind the cable 14 after the clamp 70 is closed is done in a coordinated manner with the relative displacement of the body 54 relative to the housing 29. More specifically, the unwound cable length is substantially equal to the length of the translation of the body 54 relative to the housing 29.

[0052] Comme pour le déploiement des bras 52, la pince 70 met à profit la gravité pour maintenir sa position fermée, ce qui permet de réduire la dépense énergétique de manoeuvre de la pince. Il est bien entendu que la pince 70 peut être mise en oeuvre avec l’antenne 20 décrite sur la figure 2, c'est-à-dire sans bras déployable.

[0053] Les figures 4a à 4d décrivent le principe de fonctionnement de la pince 70 entrant dans un dispositif de verrouillage conforme à l’invention. Les figures 4a, 4c et 4d représentent la pince 70 en coupe dans un plan contenant l’axe 28. La figure 4b représente la pince 70 en coupe dans un plan perpendiculaire à l’axe 28. Plus précisément, les figures 4a et 4b représentent la pince 70 en position ouverte avant sa fermeture. La figure 4c représente la pince 70 en position fermée après sa fermeture. La figure 4d représente la pince 70 en position ouverte après son ouverture.

[0054] Le câble 14 traverse la pince 70 par son axe 28 maintenu sensiblement vertical du fait du poids de l’antenne. Dans la pratique, l’axe 28 peut osciller légèrement autour de la verticale notamment du fait des conditions météorologiques dans lesquelles la mission de détection sonar est effectuée. L’important est que le poids de l’antenne génère une composante selon l’axe 28.

The clamp 70 comprises several jaws 72 which can move in translation relative to each other in a direction perpendicular to the axis 28. The movement of the jaws 72 is carried out relative to the body 54. In other words, the body 54 forms the fixed part of the clamp 70, fixed part integral with the antenna. The jaws 72 form the mobile part of the clamp 70. The jaws 72 come into contact with the cable 14 to immobilize it by clamping in the closed position of the clamp 70 and move away from the cable 14 in the open position of the clamp 70 In the open position, the cable 14 passes freely through the clamp 70 without contact with the jaws 72 and can slide freely between the jaws 72. The jaws 72 are advantageously regularly distributed radially around the axis 28 and their movement is symmetrical with respect to to axis 28. Thus the tightening of the jaws 72 on the cable 14 makes it possible for the cable 14 to retain its axis 28 in the two positions of the clamp 70. The clamp 70 comprises at least two jaws 72 opposite with respect to the axis 28. In the example shown in Figure 4b in section, four jaws 72 appear. Other number of jaws 72 are of course possible.

The body 54 has as many inclined surfaces 74 as jaws 72. The surfaces are inclined with respect to the axis 28, so as to approach the axis 28 upwards. In the example shown on the inclined surfaces 74 are made in two parts, 74a and 74b. Each inclined surface 74 can be made in more than two parts. The corresponding jaw 72 then has as many contacts with the inclined surface 74 as there are parts thereof. The contact(s) of a jaw 72 on its respective inclined surface 74 can be substantially point-like, as shown in FIGS. 4a to 4d. These substantially point-like contacts make it possible to reduce friction in the jaw 72 and its respective inclined surface. Alternatively, the contact(s) of a jaw 72 can be linear by following its respective inclined surface 74. The jaw 72 then comprises a mating inclined surface. Line contacts reduce the contact pressure. Each jaw 72 slides along

of one of the inclined surfaces 74. The sliding allows the jaws 72 to pass from the open position to the closed position of the gripper 70. In practice, the translation of the jaws 72 along their respective inclined surface breaks down into a vertical translation along the axis 28 and a horizontal translation perpendicular to the axis 28. The horizontal translation makes it possible in one direction to tighten the jaws 72 against the cable 14 and to loosen the jaws 72 in the opposite direction.

The clamp 70 comprises a first actuator 75 configured to move the jaws 72 along the axis 28 in the upward direction relative to the body 72. The upward direction is materialized by an arrow 76. Due to the support of the jaws 72 on their respective inclined surface 74, the displacement of the jaws 72 due to the actuator 75 causes the horizontal translation of the jaws 72 towards the cable 14 to tighten them on the cable 14. The tightening of the cable 14 causes the immobilization of the cable 14 relative to the jaw 72 and therefore relative to the antenna 20 or 50. FIG. 4a represents the clamp 70 still in the open position at the start of the maneuver of the actuator 75. FIG. of the actuator 75.

For the antenna 50, when the clamp 70 is in the open position, the body 54 supports only its own weight and possibly part of the weight of the arms 52 due to the joint 68. This weight is materialized by a arrow 77 in Figure 4a. On the other hand, when the clamp 70 is in the closed position, the weight of the antenna, materialized by an arrow 78 in FIG. 4b, is entirely taken up by the body 54 from which all the components of the antenna 50 are suspended.

Under the effect of the inclined surfaces 74, the weight 78 generates a horizontal component tending to increase the tightening of the jaws 72 on the cable 14. The clamp 70 can be self-locking as we will see later. Even without a self-locking configuration, the weight 78 of the antenna 50 contributes to the tightening of the jaws 72. The energy required to tighten the clamp 70 is already reduced.

The actuator 75 can be a linear cylinder, a nut cooperating with a thread made in the body 54, a cam driven by a motor with a horizontal axis and resting on an underside of the jaws 72 or any other means allowing move jaws 72 vertically.

It is possible to provide means for guiding each of the jaws 72 so that it remains in contact with its respective inclined surface. It is for example possible to provide for each of the inclined surfaces 74, a groove 79 for example T-shaped or dovetail-shaped along the inclined surface 74 and maintaining contact between the jaws 72 and its respective inclined surface 74 Alternatively, and in order to simplify the design of the clamp 70, the clamp 70 advantageously comprises elastic elements 80 configured to separate the jaws 72 from the cable 14. The elastic elements 80 allow the jaws 72 to remain permanently in contact with their inclined surface 74 respective. The elastic elements 80 are for example arranged between each of the jaws 72 and more precisely between two consecutive jaws 72.

[0062] The actuator 75 can be double-acting. In other words, the actuator 75 can move the jaws 72 up and down, up to close the clamp 70 and down to open the clamp 70. Due to the presence of the elastic elements 80, the actuator 75 can be single acting. More precisely, the actuator 75 can push the jaws 72 only upwards, the descent of the jaws 72 being ensured by the thrust of the elastic elements which drive the jaws 72 downwards under the effect of the inclined surfaces 74.

[0063] In the presence of elastic elements 80 or of a double-acting actuator 75, it is possible to dispense with the particular shape of the grooves 79 configured to hold the jaw 72 considered bearing against its respective inclined surface 74. However, it is advantageous to provide a groove 79 simply ensuring the lateral guidance of the jaws 72 each in a vertical plane. The inclined surface 74 associated with the jaw 72 considered then forms the bottom of the groove 79.

The clamp 70 includes a second actuator configured to pull the cable 14 relative to the body 54 along the axis 28 in the downward direction. The action of the second actuator is represented by the arrow 81 in Figure 4d. The second actuator allows the opening of the clamp 70. Any type of actuator allowing pulling on the cable 14 can be implemented. When a winch is present in the antenna, the second actuator is advantageously the winch 26. From the closed position of the clamp 70 shown in Figure 4c, by pulling the cable 14 downwards the jaws 72, again tightened on the cable 14, are driven downwards, slide along their respective inclined surface 74 and therefore tend to loosen from the cable 14. Under the effect of the elastic elements 80, the loosening continues to reach the open position of the clamp 70 shown in Figure 4d. The presence of the elastic elements 80 makes it possible to open the clamp 70 as widely as possible in order to avoid as much as possible the risk of the jaws 72 rubbing against the cable 14 when the clamp 70 is in the open position. Furthermore, the presence of the elastic elements 80 makes it possible to simplify the action of the second actuator in its action to open the clamp 70. Indeed, from the start of the traction on the cable 14, the tightening of the jaws 72 on the cable 14 disappears and the jaws 72 are then driven by the elastic elements 80 along their respective inclined surface 74 and the gripper 70 reaches its open position. In practice, during an acoustic detection phase, the clamp 70 is in the closed position. At the end of this phase, when it is desired to raise the antenna towards the wearer, it suffices to actuate the winch 26 to open the clamp 70 and raise the antenna. A single actuator is needed to open the clamp 70 and raise the antenna.

[0065] Les figures 5 et 6 permettent d’illustrer les paramètres à choisir pour obtenir une pince 70 autobloquante. Une telle pince permet de ne manœuvrer l’actionneur 75 que pour atteindre le serrage de la pince 70. Une fois le serrage atteint, il est possible d’interrompre la manœuvre de l’actionneur 75. Le poids 78 de l’antenne suffit à maintenir la pince 70 fermée.

[0066] Sur la figure 5 deux mors 72 sont représentés à l’intérieur du corps 54.

The inclination of the inclined surfaces 74 is represented by an angle α. Clamp 70 is in the closed position. Subsequently it is assumed that the gripper 70 comprises only two jaws 72. The following reasoning applies for a greater number of jaws 72. It is also assumed that the inclined surfaces 74 of the two jaws 72 all have the same inclination a. The weight 78 of the antenna is denoted P. At the level of each inclined surface 74, the weight P breaks down into two forces T each applied to a jaw 72. Due to the inclination a, we have:

T = P/sin a

At the interface between each jaw 72 and the cable 14, the force T breaks down into a clamping force S:

S = T cos a

[0068] hence:

S = P/tan a

The tightening of the cable 14 can cause its immobilization only if a coefficient of friction noted f2 exists between the jaws 72 and the cable 14. By calling V the vertical force exerted on the cable due to the tightening of the jaws 72, we has :

V= f2 . S

[0070] hence:

V = f2 . P/tan a

[0071] For the weight P to be sufficient to maintain the immobilization of the cable 14 due to the tightening of the jaws 72, in other words for the clamp (70) to be self-locking, it is necessary that:

f2 . P/tan a > P

[0072] hence:

P (f2/tan a - 1 ) > 0

[0073] therefore:

f2 > tan a

[0074] The condition providing that the coefficient of friction f2 between the jaws 72 and the cable 14 must be greater than or equal to the tangent of the inclination a of the inclined surfaces assumes the absence of friction at the contact between the jaws 72 and their respective inclined surfaces 74.

Figure 6 illustrates the possibility of implementing a gripper in which the friction, denoted f 1 , at the contact between the jaws 72 and their respective inclined surfaces 74 is not zero. On the left part of FIG. 6, zero friction f1 is considered, which in practice can be achieved by arranging bearings between the body bearing here the mark 54.1 and the jaw 72.1. It is also possible to implement for the surfaces in contact materials with a very low coefficient of friction such as for example polytetrafluoroethylene (PTFE). On the right part of FIG. 6, a non-zero friction f1 between the body 54.2 and the jaw 72.2 is considered. In this second case, the condition stated above allowing the self-blocking of the gripper 70 can be written:

f2 > tan (a + Arc tan f1 )

In order to properly balance the forces undergone by each of the jaws 72, these advantageously each have a section in the shape of a rectangular trapezium in a radial plane around the axis 28 of the cable 14. The radial plane is that of the figures 4a, 4c, 4d, 5 and 6. The rectangular trapezium is clearly visible in Figures 5 and 6. The rectangular trapezium has a side 90 bordered by two right angles is parallel to the axis 28 of the cable 14. The side 90 belongs to a first face 91 of the jaw 72 coming into pressure on the cable 14. The side 92 of the trapezium, opposite the side 90, belongs to a second face of the jaw 72 coming into contact with the inclined surface 74.

[0077] Figure 7 shows in partial section, in a plane perpendicular to the axis 28, the cable 14 clamped between two jaws 72. Figure 7 illustrates an example shape of the face 91 of the jaws 72, face coming in contact with cable 14. Face 91 has a shape complementary to that of cable 14. In the example shown, cable 19 has a circular section. The faces 91 of each of the jaws 72 are therefore in cylindrical portion. The cable 14 could have a section other than a circular section. The faces 91 of the jaws would then follow the section of the cable. The complementary shapes of the jaws 72 and the cable 14 make it possible to reduce the pressure exerted by the jaws 72 on the cable 14. By limiting the pressure, the cable 14 deforms little under the tightening of the jaws 72.

In Figures 4a to 4d, the body 54 forms the fixed part of the clamp 70.

Alternatively, the fixed part of the clamp can be floating relative to the body 54. In the open position of the clamp, the fixed part can retain at least one degree of freedom in translation along the axis 28 relative to the body 54. This degree of freedom facilitates the closing of the clamp when the antenna 50 is descending or ascending. This degree of freedom makes it possible to limit the friction of the movable part on the cable 14 when closing the clamp.

More specifically, in Figures 8a, 8b and 8c, the clamp bears the mark 100 and its fixed part, in which the inclined surfaces 74 are made, bears the mark 102. The fixed part 102 is connected to the body 54 by allowing a translational movement along the axis 28 between the body 54 and the fixed part 102. A spring 104 connects the fixed part 102 to the body 54. The spring 104 can be compressed by bringing the fixed part 102 closer to the body 54. On the Figure 8a, the clamp 100 is in the open position. The fixed part 102 is located under the body 54 at a distance from the body 54. The cable 14 can circulate freely between the jaws 72. FIG. here, moves the jaws 72 to bring them into pressure against the cable 14. At the start of tightening, the spring 104 still remains relaxed as in FIG. 8a. Then, as shown in Figure 8c, gravity acts on the body 54 and the spring 104 compresses bringing the fixed part 102 into abutment against the body 54, via the fully compressed spring 104. Alternatively, it is possible to provide specific stops directly between the fixed part 102 and the body 54. In other words, in the position of FIG. 8c, the degree of freedom in translation of the clamp 100 relative to the body 54 according to the axis 28 is deleted.

The spring 104 also allows flexibility of the fixed part 102 with respect to the body 54 according to the other degrees of freedom. This can improve the centering of the cable 14 crossing the clamp 100. In other words, in addition to the degree of freedom in translation along the axis 28, the other degrees of freedom can have an advantage. Alternatively to the presence of the spring 104, any other slide along the axis 28 allowing a translational movement of the fixed part 102 relative to the body 54 can be implemented. This translation makes it possible to limit the slippage of the cable 14 between the jaws 72 when the clamp 100 is closed. More precisely, it may be desirable to tighten the clamp while the antenna is descending. With a clamp 70 whose fixed part is integral with the body 54 when tightening the clamp, the antenna loses speed and the clamp acts as a brake by rubbing on the cable 14. All of the kinetic energy of the antenna is dissipated by this friction, which leads to wear of the cable 14 and of the jaws 72. On the contrary, with the clamp 100, only the kinetic energy due to the mass of the clamp 100 is dissipated by friction on the cable 14. The clamp 100 having a much lower mass than that of the entire antenna, and at most, less than half the mass of the antenna, most of the kinetic energy of the antenna is transformed into potential energy in the compression of the spring 104, thus limiting the energy dissipated by friction between the jaws 72 and the cable 14 and therefore the wear thereof. If it is desired to close the clamp while the antenna is rising, reverse mounting of the spring 104 is possible.

[0081] The spring 104 can be replaced by other types of elastic elements such as elastomers. The elastic element may have damping properties making it possible to dissipate the potential energy resulting from the kinetic energy of the gripper. It is for example possible to implement a damper instead of or in addition to the spring 104. Some elastomeric materials also have damping properties in addition to their elastic property.

[0082] The compression of the spring 104 to limit the friction on the cable works both when lowering and when raising the antenna. In the example shown in Figures 8a, 8b and 8c the spring 104 compresses when tightening the clamp. Alternatively, it is possible to provide a spring that stretches when the clamp is tightened. The bottom of the fixed element 102 is then fixed to a spring which is itself fixed to the body 54, located this time under the fixed element 102. It is also possible to arrange the fixed element 102 between two springs, each of them being fixed on the one hand to the fixed element 102 and on the other hand to the body 54.

The assembly described using Figures 8a to 8c is described to be implemented with the clamp 70. Such an assembly with an elastic element 104 can be implemented for other types of clamp.

CLAIMS

1. Device for locking an object (20; 50) hanging from a cable (14), the device comprising a cable (14) and a clamp (70), the cable (14) passing through the clamp (70) at s extending along a substantially vertical axis (28), the gripper (70) comprising: a fixed part (54; 102) connected to the object (20; 50), at least two movable jaws (72), a first actuator ( 75) and a second actuator (26), the two jaws (72) being able to move in translation relative to each other in a direction perpendicular to the axis (28) of the cable (14), the two jaws (72) coming into contact with the cable (14) to immobilize the cable (14) by clamping in a closed position and moving away from the cable (14) in an open position, the fixed part (54; 102) having as many surfaces inclined (74) than jaws (72),the inclined surfaces (74) being inclined with respect to the axis (28) of the cable (14), so as to approach the axis (28) of the cable (14) upwards, each of the jaws (72) being configured to slide along one of the inclined surfaces (74), the sliding allowing the jaws (72) to move from the open position to the closed position, the gripper (70) further comprising elastic elements (80) configured to separating the jaws (72) from the cable (14), the first actuator (75) being configured to move the jaws (72) upwards, to make them slide along their respective inclined surface (74) and to allow the closure of the clamp (70), the second actuator (26) being configured to pull the cable (14) relative to the fixed part (54; 102) downwards and allow the opening of the clamp (70).so as to approach the axis (28) of the cable (14) upwards, each of the jaws (72) being configured to slide along one of the inclined surfaces (74), the sliding allowing the jaws (72 ) to pass from the open position to the closed position, the clamp (70) further comprising elastic elements (80) configured to separate the jaws (72) from the cable (14), the first actuator (75) being configured to move the jaws (72) upwards, sliding them along their respective inclined surface (74) and allowing the clamp (70) to close, the second actuator (26) being configured to pull the cable (14) by relative to the fixed part (54; 102) downwards and allow the opening of the clamp (70).so as to approach the axis (28) of the cable (14) upwards, each of the jaws (72) being configured to slide along one of the inclined surfaces (74), the sliding allowing the jaws (72 ) to pass from the open position to the closed position, the clamp (70) further comprising elastic elements (80) configured to separate the jaws (72) from the cable (14), the first actuator (75) being configured to move the jaws (72) upwards, sliding them along their respective inclined surface (74) and allowing the clamp (70) to close, the second actuator (26) being configured to pull the cable (14) by relative to the fixed part (54; 102) downwards and allow the opening of the clamp (70).each of the jaws (72) being configured to slide along one of the inclined surfaces (74), the sliding allowing the jaws (72) to pass from the open position to the closed position, the gripper (70) further comprising elastic elements (80) configured to separate the jaws (72) from the cable (14), the first actuator (75) being configured to move the jaws (72) upwards, to slide them along their respective inclined surface (74 ) and allow the clamp (70) to be closed, the second actuator (26) being configured to pull the cable (14) relative to the fixed part (54; 102) downwards and allow the clamp to be opened (70).each of the jaws (72) being configured to slide along one of the inclined surfaces (74), the sliding allowing the jaws (72) to pass from the open position to the closed position, the gripper (70) further comprising elastic elements (80) configured to separate the jaws (72) from the cable (14), the first actuator (75) being configured to move the jaws (72) upwards, to slide them along their respective inclined surface (74 ) and allow the clamp (70) to be closed, the second actuator (26) being configured to pull the cable (14) relative to the fixed part (54; 102) downwards and allow the clamp to be opened (70).the gripper (70) further comprising elastic members (80) configured to move the jaws (72) apart from the cable (14), the first actuator (75) being configured to move the jaws (72) upwards, sliding them along their respective inclined surface (74) and allow the clamp (70) to close, the second actuator (26) being configured to pull the cable (14) relative to the fixed part (54; 102) towards the bottom and allow the opening of the clamp (70).the gripper (70) further comprising elastic members (80) configured to move the jaws (72) apart from the cable (14), the first actuator (75) being configured to move the jaws (72) upwards, sliding them along their respective inclined surface (74) and allow the clamp (70) to close, the second actuator (26) being configured to pull the cable (14) relative to the fixed part (54; 102) towards the bottom and allow the opening of the clamp (70).102) downwards and allow the clamp (70) to open.102) downwards and allow the clamp (70) to open.

2. Locking device according to claim 1, wherein the elastic elements (80) are arranged between each of the jaws (72) and tend to separate the jaws (72) from each other.

3. Locking device according to one of the preceding claims, wherein the jaws (72) are regularly distributed radially around the axis (28) of the cable (14) and wherein the movement of the jaws (72) is symmetrical with relative to the axis (28) of the cable (14).

4. Locking device according to one of the preceding claims, wherein the fixed part (54; 102) comprises as many grooves (79) as there are jaws (72), each jaw (72) sliding in one of the grooves (79) , the inclined surface (74) associated with the jaw (72) considered forming a bottom of the groove (79), the groove (79) being configured to provide lateral guidance of the jaw (72) considered in a radial plane around the axis (28) of the cable (14).

5. Locking device according to one of the preceding claims, wherein in a radial plane around the axis (28) of the cable (14), each jaw (72) has a section substantially in the shape of a rectangular trapezoid of which a first side (90) bordered by two right angles is parallel to the axis (28) of the cable (14) and belongs to a first face (91) of the jaw (72) considered, the first face (91) being configured to come into pressure on the cable (14) and of which a second side (92), opposite the first side (90), belongs to a second face of the jaw (72) in question, the second face coming into contact with an inclined surface (74) .

6. Locking device according to one of the preceding claims, in which the inclined surfaces (74) are inclined by an angle a with respect to the axis (28) of the cable (14), in which a coefficient of friction f2 is defined between the jaws (72) and the cable (14) and in which the coefficient of friction f2 is greater than or equal to the tangent of the angle a so as to make the gripper (70) self-locking under the effect of the weight of the object (20; 50).

7. Locking device according to claim 6, in which a coefficient of friction f1 is defined between each jaw (72) and the corresponding inclined surface (74), the coefficient of friction f1 being substantially zero.

8. Locking device according to claim 6, in which a coefficient of friction f1 is defined between each jaw (72) and the corresponding inclined surface (74) and in which the coefficient of friction f2 is greater than or equal to the tangent of the sum of the angle a and of the arc-tangent f1 so as to make the gripper (70) self-locking under the effect of the weight of the object (20; 50).

9. Locking device according to one of the preceding claims, wherein the second actuator is a winch (26) disposed inside the object (20; 50) and configured to wind and unwind the cable (14) .

10. Locking device according to one of the preceding claims, wherein each jaw (72) comprises a first face (91) coming into pressure on the cable (14) and wherein the first face (91) has a complementary shape of that of the cable (14).

11. Locking device according to one of the preceding claims, wherein the fixed part (102) has a degree of freedom in translation along the axis (28) relative to the object (20; 50).

12. Locking device according to claim 11, wherein the fixed part (102) is connected to the object (20; 50) by means of a second elastic element (104).

13. Locking device according to claim 12, wherein the second elastic element (104) is configured to allow flexibility of the fixed part (102) relative to the object (50) in translation along the axis (28) and also according to the other degrees of freedom.

14. Locking device according to one of claims 12 or 13, in which the elastic element (104) is configured to transform a major part of the kinetic energy of the object (50) into potential energy in the deformation of the elastic element (104).

15. Locking device according to one of claims 12 to 14, wherein the elastic element (104) has damping properties making it possible to dissipate the potential energy resulting from the kinetic energy of the object (50) .