Abstract:
An anchoring harpoon intended in particular for an aircraft, capable of cooperating with an anchoring grate of a platform, includes jack elements including a cylinder element containing mobile piston elements provided with a rod that extends beyond the cylinder element, the free end of which includes a harpoon head ( 7 ) that is hooked in the grate and includes retaining fingers ( 8, 13, 14 ) that can be moved between a retracted position and an active position by control elements ( 9 ). The control element ( 9 ) for controlling the movements of the fingers include a control piston ( 18 ) which can slide inside the rod of the jack and which is associated with a bistable actuator ( 19 ) of the fingers, capable of moving between a retracted position and an active position in which the fingers are deployed with the application of successive pressure pulses in the jack elements.

Description:
The present invention concerns an anchoring harpoon intended in particular for an aircraft able to cooperate with an anchoring grate of a platform, and an anchoring system including one such harpoon. 
     Such harpoons and such anchoring systems are already generally known in the state of the art. 
     Thus for example, document FR-A-2 701 689 describes a harpoon intended to equip a rotocraft such as a helicopter, for example, and that can be pulled towards a landing platform of a vessel so that the head of the harpoon attaches on the grate and thus forms an anchoring point of the aircraft, in particular facilitating the landing operation thereof. 
     The anchoring harpoon described in the aforementioned document includes cylinder means wherein piston means move provided with a shaft extending beyond the cylinder means and the free end of which includes a harpoon head for hooking in the grate. This harpoon head is in fact provided with retaining fingers for retention in the grate, radially movable between a retracted position and an active position using control means. 
     Such harpoons have already been successfully implemented on a number of vessels to ensure anchoring in particular of helicopter-type aircrafts. 
     For some time, a number of attempts have also been made to land drone-type rotocrafts on platforms, in particular military ones. 
     The applicant has also successfully developed and tested an automatic landing and take-off system for a rotary-wing drone on and from such a vessel. 
     The implementation of these drones also requires the use of harpoons and anchoring grates. 
     Studies have shown that adapting already known anchoring harpoons for helicopters directly on rotary-wing drones could not be done successfully. 
     Indeed, these studies have shown problems related to size, power, maintenance, etc. 
     The aim of the invention is therefore to resolve these problems. 
     SUMMARY OF THE INVENTION 
     To that end, the invention concerns an anchoring harpoon, intended in particular for an aircraft, able to cooperate with an anchoring grate of a platform, including jack means comprising cylinder means containing mobile piston means provided with a rod that extends beyond the cylinder means and the free end of which includes a harpoon head that is hooked in the grate, provided with retaining fingers for retention therein, that can be moved between a retracted position and an active position by control means, characterized in that the means for controlling the movements of the fingers comprise a control piston that can slide inside the rod of the jack and that is associated with a bistable actuator of the fingers, capable of moving between a retracted position and an active position in which the fingers are deployed with the application of successive pressure pulses in the jack means. 
     According to other features of the invention, considered separately or in combination: 
     the bistable actuator is a rotary mechanical jack, 
     the bistable actuator includes a wheel with beveled teeth inserted between the control piston and a rod for actuating the fingers, positioned in a sleeve connected to the jack rod, the end of the piston opposite the wheel with beveled teeth itself including teeth, so as, when pressure pulses are applied in the jack means and therefore the control piston moves, to cause the beveled toothed wheel to rotate in the sleeve, the teeth of the wheel also being adapted to cooperate with successive notches having different heights of the sleeve, in order to define stable positions, active and retracted, of the rod for actuating the fingers, 
     it includes a spring for stressing the rod for actuating the fingers in the retracted position, 
     the cylinder means of the jack include at least two cylinder portions telescoping one in the other and capable of being moved between a retracted position one in the other and an active position with one protruding relative to the other, 
     the jack means are connected to a pressurized fluid source through control means and said pressurized fluid source includes a consumable gas cartridge, 
     the gas is CO 2 , 
     the control means comprise solenoid valve means steered upon opening and closing to feed the jack means, 
     the corresponding end of the jack means is associated with the aircraft and a helical return and pressing spring is inserted between said end of the jack and the harpoon head, 
     the helical spring is arranged around the jack means, 
     it includes trigger means for prohibiting the movement of the fingers towards their active position when the harpoon head is not positioned abutting in the anchoring grate. 
     The invention also concerns an anchoring system, in particular for a drone-type rotocraft comprising an anchoring harpoon as previously described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood using the following description, provided solely as an example, and done in reference to the appended drawings, in which: 
         FIGS. 1 and 2  show cross-sectional views of an anchoring harpoon according to the invention in the retracted and active anchoring positions, respectively, in an anchoring grate of a platform, 
         FIG. 3  illustrates an exploded perspective view of a hooking harpoon head included in a harpoon according to the invention, 
         FIG. 4  shows a summary diagram illustrating the pressurized fluid supply of a harpoon according to the invention, and 
         FIG. 5  illustrates the operation of such a harpoon. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     These figures, and in particular  FIGS. 1 and 2 , illustrate an anchoring harpoon, intended in particular for an aircraft on a platform of the military vessel type or another type. 
     The aircraft can for example be a rotary-wing drone. 
     This harpoon is designated by general reference  1  in these figures and is adapted to cooperate with an anchoring grate of the platform, this grate being designated by general reference  2  in these figures. 
     Indeed, the harpoon includes jack means designated by general reference  3 , including cylinder means designated by general reference  4 , wherein piston means designated by general reference  5  move. 
     These piston means are provided with a rod  6  extending beyond the cylinder means and whereof the free end includes a harpoon head that hooks in the grate, said harpoon head being designated by general reference  7 . 
     In fact and as described in the aforementioned prior art document, this harpoon head is provided with retaining fingers for retention in the grate, capable of being radially moved between a retracted position and an active position by control means, as will be described in more detail hereinafter. 
     In these figures, one of the fingers is designated by general reference  8  and the control means thereof by general reference  9 . 
     The structure of these control means will also be described in more detail relative to  FIG. 3 . 
     Returning to  FIGS. 1 and 2 , the fingers and the control means are shown in the retracted position in  FIG. 1  and the active position in  FIG. 2 , when the harpoon is deployed, the control means being movable in the rod to cause a radial movement of the retaining fingers between the retracted position, in  FIG. 1 , in the head of the harpoon, and the active retaining position in  FIG. 2 , radially protruding relative to said head to lock it in the grate. 
     To resolve the various problems of integration in a drone, in particular as previously described, in the anchoring harpoon according to the invention, the cylinder means of the jack comprise at least two cylinder portions telescoping one in the other and capable of being moved between a position with one retracted in the other and an active anchoring position with one protruding relative to the other, as illustrated in  FIGS. 1 and 2 , respectively. 
     In these figures, the two cylinder portions telescoping one in the other are designated by references  10  and  11 , respectively. 
     The upper cylinder portion  10  is then associated with hooking means for hooking on the drone, said means having any suitable traditional structure, while the other end of this upper cylinder portion  10  is adapted to receive the lower cylinder portion  11 , which itself supports the rod  6  whereof the free end supports the harpoon head  7 . 
     The jack means are then connected to a pressurized fluid source through control means to control their operation, i.e. the deployment of the anchoring harpoon and its hooking or unhooking relative to the anchoring grate. 
     To that end, a helical return and pressing spring  12  is inserted between the end of the upper cylinder portion associated with the aircraft and the harpoon head to ensure, as illustrated in  FIG. 2 , when the harpoon head is anchored in the grate, correct pressing of the drone on the platform. 
     The harpoon head  7  can be similar to that already described in the document previously mentioned and for example include three retaining fingers arranged 120° from each other and for example designated by general references  8 ,  13  and  14  in  FIG. 3 . These fingers can then be moved between a retracted position and an active position radially protruding relative to the rest of the head in order to anchor the harpoon in the grate under the control of the control means designated by general reference  9  in  FIGS. 1 ,  2  and  3 . 
     Also traditionally, the harpoon head  7  can include an arming trigger for these control means  9  to prohibit the movement of the fingers towards their active position when the harpoon head is not positioned abutting in the anchoring grate, i.e. in the correct anchoring position in the grate. 
     This trigger was also previously described and is designated by general reference  15  in  FIG. 3 . 
     This trigger  15  is then positioned transversely in the harpoon head  7 , protrudes radially from the head, and is associated with a spring  16  and a stop member  17  to be pushed back in the harpoon head when the latter is in its correct position in the anchoring grate as illustrated in  FIG. 2 , and to allow the control means  9  and the retaining fingers to move. 
     The control means  9  comprise a piston designated by general reference  18  capable of sliding in the rod of the jack and associated with a bistable actuator of the fingers, capable of being moved between retracted and active, deployed positions of the fingers with the application of successive pressure pulses in the jack means. 
     This bistable actuator of the fingers is designated by general reference  19  and includes several pieces forming what is commonly called a rotary lock. 
     This bistable actuator in fact includes a wheel with beveled teeth that is designated by general reference  20  in  FIG. 3 , inserted between the control piston  18  and an actuating rod of the fingers designated by general reference  21  in  FIG. 3 . 
     The piston  18  and the beveled toothed wheel  20  are arranged in a sleeve designated by general reference  22  connected to the rod  6  of the jack for example through a pin designated by general reference  23 . 
     A spring for stressing the actuating rod  21  of the fingers in the retracted position is also provided, said spring being designated by general reference  24  in  FIG. 3 . 
     The end of the piston  18  opposite the beveled toothed wheel itself includes teeth like the tooth designated by general reference  25  in that figure, so as, when pressure pulses are applied in the jack means and therefore corresponding movements of the piston  18  occur, to make the beveled toothed wheel  20  rotate in the sleeve  22 . The beveled teeth  20  of the wheel are also adapted to cooperate with successive notches having different heights of the sleeve  22  in order to define stable positions, active and retracted, in the actuating rod  21  of the fingers and therefore of said fingers. 
     Two successive notches with different heights of the sleeve are for example designated by general references  26  and  27  in that figure. 
     In the retracted position of the control means  9 , the teeth of the wheel  20  for example bear against the notches such as the notch  26 . When pressure is applied in the jack means, the piston  18  causes the toothed wheel  20  and the actuating rod  21  to move against the elastic stress of the spring  24  if the trigger  15  is armed, i.e. pushed back, the head being in the correct position in the grate. 
     During this pushing, the teeth  25  of the piston  18  also tend to cause the toothed wheel to rotate. However, this rotational movement of the wheel is prevented by the cooperation of the teeth of the wheel with the edges of the sleeve  22  of each side of the notch  26  until the beveled teeth of the wheel  20  can cross the corresponding end of the sleeve  22  to cooperate with the notch  27  for maintaining the teeth and therefore of the actuating rod  21  in the active deployed position of the fingers of the hooking head. 
     Locking in position is thus ensured by stressing the spring  24 , which pushes the actuating rod  21  and the toothed wheel  20  to remain in position against the notch  27 . 
     The fluid pressure can then be released in the jack means while keeping the aircraft anchored in the grate. 
     A new application of a fluid pressure pulse in the jack means causes a new angular movement of the beveled toothed wheel opposite the following notch corresponding to the retracted position of the rod of the actuating means under the action of the spring  24  in order to unlock the head. 
     It of course goes without saying that other embodiments of this bistable actuator controlled by applying successive pressure pulses in the jack means can be considered. 
     It can thus be conceived that the use of such a bistable mechanical lock can make it possible to use only pressure pulses in the jack means and no longer requires that pressure be maintained therein as was the case with the jack means of the prior art. 
     A single pressure pulse indeed makes it possible to deploy the fingers, and a single additional pressure pulse makes it possible to retract them back in. 
     Moreover, it also makes it possible to modify the pressurized fluid supply means of the jack means. 
     A summary diagram of these supply means is provided in  FIG. 4 . 
     Indeed, the supply means can include a pressurized fluid source for example assuming the form of a consumable gas cartridge, for example such as a consumable CO 2  cartridge, designated by general reference  30  in that figure. 
     This gas cartridge  30  is then removed at the inlet of the solenoid valve means  3 / 2  that are normally closed, designated by general reference  31 , itself connected to adjustable restricting means making it possible to limit the gas flow rate during harpooning and bleeding, designated by general reference  32 . 
     A pressure relief valve adjusted to a pressure slightly higher than the desired harpooning pressure is also provided, said valve being designated by general reference  33 , the harpoon still being designated by general reference  1 . 
     The control upon opening and closing of the solenoid valve means thus makes it possible to steer the supply of the jack means in the form of pressure pulses. 
     This pulse-based operation is illustrated in  FIG. 5 , which shows that the harpooning and release of harpooning are done through successive applications of pressure pulses in the jack means, which makes it possible on one hand to deploy the telescoping harpoon, which remains in the deployed position as long as the anchoring head is locked in the grate, and which also makes it possible to obtain a force pressing the aircraft on the platform. 
     Applying a pressure pulse by controlling the opening of the solenoid valve means  31  previously described can allow cylinder portions of the jack means to deploy in order to make the hooking head of the harpoon penetrate the grate. 
     The harpoon head is then housed in a cell of the grate, which makes it possible to push back the arming trigger  15  and therefore the piston  18 , under the action of the pressure of the fluid in the jack means, to push the actuating rod  21  of the fingers  8  towards the deployed position of said fingers in order to lock the head in the grate. 
     The rotary bistable mechanical lock makes it possible to lock the rod and the fingers in said active position anchoring the head in the grate and the fluid pressure can then be released in the jack means, the helical return and pressing spring  12  making it possible to keep the drone pressed in position on the grate. 
     When a new pressure pulse is applied in the jack means, the piston  18  causes the beveled toothed wheel  20  to rotate to unlock the rotary mechanical lock, which allows, when the fluid pressure is released in the jack means, the spring  24  to push the actuating rod  21  of the fingers back, towards a retracted position, and allows said fingers to return to a position retracted in the anchoring head, which releases said anchoring head from the grate and makes it possible, via the helical spring  12 , to return the jack means towards a retracted position ( FIG. 1 ). 
     It is then seen that such a structure has a certain number of advantages relative to the harpoons of the state of the art. 
     The use of a telescoping jack in fact makes it possible to double the deployment travel of the harpoon for a same folded length and therefore considerably decrease the length of the harpoon in the folded position, which makes it possible to adapt to the bulk constraints related to placing it on board a drone. 
     The use of a pressing and return spring placed outside the jack means also makes it possible to obtain a correct pressing force against the grate. 
     The use of a bistable actuator with a rotary mechanical lock makes it possible to maintain the harpoon in its position between two pulse orders to change state, i.e. folded or locked in the grate. 
     The transition from one state to the other is done by applying a pulse of the pressurized fluid in the jack means. This then makes it possible to use a consumable cartridge, for example a gas cartridge, associated with solenoid valve control means to ensure the supply. 
     Of course, different embodiments of the described parts can be considered and other applications can also be considered, for example for anchoring aircrafts on oil or other platforms.