EP0188970B1 - Actuating device to be used in a high-pressure fluid - Google Patents

Description

The present invention relates to an actuating device of the pusher type usable in a fluid under high pressure, for example on board an underwater vehicle capable of working at great depth.

Many submarine equipment and devices require the use of actuators with a mechanical effect, either to transmit a force (release of ballast, seizure of objects, etc.), or to effect locking or unlocking. Most systems are based on the amplification of forces using levers driven by mechanical or hydraulic systems; in the latter case, a hydraulic unit must be loaded on board the vehicle. These various devices must be used at extremely variable immersion levels, for example at a depth of 0 to 11,000 meters in the case of underwater use, or in a liquid which can be charged with solid suspensions. The main problem is to maintain the best level of reliability (especially in the case of a ballast width), which makes the design of these devices very delicate.

The object of the present invention is precisely to remedy these drawbacks by proposing a device which can operate independently of the pressure, the corrosive action and the turbidity of the ambient medium by using the linear displacement of a piston, this displacement being effected with very high reliability and requiring little energy.

The actuating device object of the invention is defined in claim 1, and comprises, in a conventional manner, a pusher movable relative to a structure and connected to it by elastic means, for example a spring, as well as means for locking the pusher relative to this structure. According to the invention, at least part of the pusher, said elastic means and the locking means are inside a frame containing a second fluid and the device comprises means allowing the pressure of the fluid contained in the frame to constantly adapt to that of the external fluid.

For the sake of simplification, the expression “first fluid” will be used in the remainder of this text to designate the fluid in which the entire device works and “second fluid” to designate the fluid which is inside the built.

• - une jupe souple ayant une première extrémité fixée de manière étanche au poussoir mobile et une deuxième extrémité fixée de manière étanche au bâti, cette jupe souple séparant les premier et deuxième fluides, et
• - au moins un manchon déformable fixé de manière étanche au bâti et dont l'intérieur communique avec l'espace intérieur de ce bâti, ledit manchon séparant les premier et deuxième fluides et étant apte à se déformer sous l'effet des variations de la pression du premier fluide.

In the preferred embodiment, the means allowing the pressure of the second fluid to constantly adapt to that of the first include:

• a flexible skirt having a first end fixed in sealed manner to the movable pusher and a second end fixed in sealed manner to the frame, this flexible skirt separating the first and second fluids, and
• - At least one deformable sleeve tightly fixed to the frame and the interior of which communicates with the interior space of this frame, said sleeve separating the first and second fluids and being able to deform under the effect of variations in pressure of the first fluid.

According to another aspect of the invention, there is provided inside the frame at least one partition pierced with a conduit allowing the passage of the second fluid. Indeed, it moves inside the frame when the device is put into operation and the diameter of the duct (s) is calculated according to the force which must be exerted by the pusher during the operation of the device.

• - une pièce de verrouillage mobile entre une position de verrouillage du poussoir et une position de déverrouillage,
• - un électroaimant, et
• - un plongeur mobile à l'intérieur du bâti et relié à celui-ci par des moyens élastiques, ce pion- gueur pouvant venir en contact avec l'électro aimant et coopérant avec ladite pièce de verrouillage.de manière à maintenir celle-ci en position de verrouillage lorsque le plongeur se trouve en contact avec l'électroaimant.

According to another characteristic of the device which is the subject of the invention, the means for locking the pusher comprise:

• a movable locking part between a position for locking the pusher and an unlocking position,
• - an electromagnet, and
• - A movable plunger inside the frame and connected to it by elastic means, this pioneur being able to come into contact with the electromagnet and cooperating with said locking part. so as to maintain the latter in locking position when the plunger is in contact with the electromagnet.

The locking piece can be either a rocker movable in rotation about a fixed axis relative to the frame or a free rocker or even be constituted by a set of movable balls inside a housing provided in the frame.

In a first embodiment, the electromagnet creates a magnetic field, and therefore only attracts the plunger, when it is traversed by an electric current. In a second embodiment, the electromagnet comprises a coil with permanent magnetization, this magnetization being canceled by the passage of a current in the coil: thus, in this version, the plunger is only attracted by the electromagnet when the supply circuit is open. Finally, one can provide inside the frame a screw-nut system controlled by a motor for returning the pusher to its locked position.

• - la figure 1 est une vue schématique montrant un engin sous-marin travaillant au fond de la mer et équipé d'un dispositif d'actionnement conforme à l'invention,
• - la figure 2 est une vue schématique en coupe du dispositif d'actionnement objet de l'invention lorsque le poussoir est en position verrouillée,
• - la figure 3 est une vue schématique simplifiée semblable à la figure 2 et illustrant la position de l'ensemble après le fonctionnement du dispositif,
• - la figure 4 est une vue schématique en coupe illustrant le système vis-écrou permettant de ramener le poussoir en position de verrouillage,
• - la figure 5 est une vue schématique partielle illustrant le cas où la pièce de verrouillage est constituée par un ensemble de billes, et
• - la figure 6 est une vue schématique semblable à la figure 5 illustrant le cas où la pièce de verrouillage est constituée par un basculeur libre.

The invention will appear better on reading the description which follows, given purely by way of illustration and in no way limiting, with reference to the appended drawings in which:

• FIG. 1 is a schematic view showing an underwater vehicle working at the bottom of the sea and equipped with an actuating device according to the invention,
• FIG. 2 is a schematic sectional view of the actuating device which is the subject of the invention when the pusher is in the locked position,
• FIG. 3 is a simplified schematic view similar to FIG. 2 and illustrating the position of the assembly after the device has operated,
• FIG. 4 is a schematic sectional view illustrating the screw-nut system making it possible to return the pusher to the locked position,
• FIG. 5 is a partial schematic view illustrating the case where the locking piece is constituted by a set of balls, and
• - Figure 6 is a schematic view appeared ble in Figure 5 illustrating the case where the locking piece is constituted by a free rocker.

If we refer to Figure 1, we see an underwater vehicle 2, for example a nodule pickup machine, which moves on the seabed while being either remote controlled from a ship 4 or autonomous . Egin 2 is moved using Archechedes screws 6 and may include one or more tanks such as 8 containing a ballast 10. In some cases of operational incidents, it may be necessary to release the ballast 10 so that machine 2 rises to the surface. This can be done for example by opening a door or a hatch 12 using an actuating device 14 such as that which is the subject of the invention.

This device appears better on the detailed sectional view of Figure 2. We see that this device consists of a sealed frame 16 inside which can move a pusher 18. The frame 16 is filled with a fluid called "Second fluid" as opposed to the first fluid which is the one in which the machine is immersed. The rear part 20 of the pusher 18 is hollow and contains a spring 22, one end of which is fixed to the pusher 18 while its other end is fixed to a part 24 integral with the frame 16. A flexible skirt 26, the rote of which will be explained later , is fixed in a sealed manner, on the one hand to the front part of the pusher 18 and on the other hand to the frame 16. FIG. 2 illustrates the locking position in which the pusher 18 is held using a rocker 28 which can pivot about an axis 30 fixed relative to the frame 16. The rocker 28 carries at one of its ends a rounded part 32 which, in the locking position illustrated in FIG. 2, is in contact with a flange 34 provided on the rear part 20 of the pusher 18 and thus prevents any movement of the latter. In this position, the spring 22 is in the compressed state.

The rotation of the rocker 28 is prevented by a plunger 36 also movable inside the frame 16. This plunger 36 consists of a body 38 and a head 40 which can come into contact with an electromagnet 42. The latter is connected to a supply device (not shown) by a set of wires contained in a cable 43. A spring 44 has one of its ends fixed to the body 38 of the plunger 36 and the other end fixed to the part 24 integral with the frame 16. It can be seen in FIG. 2 that the head 40 of the plunger 36 has dimensions such that, when it is in contact with the electromagnet 42, it abuts against a rounded part 36 provided at the end of the rocker 28 opposite the rounded part 32, which prevents any pivoting of the rocker in the anticlockwise direction seen in FIG. 2 and keeps the pusher 18 in the locked position.

We also see in Figure 2 two deformable sleeves 48 fixed in sealed manner to the frame 16 so that their interior space communicates with the interior space of this frame via conduits such as 50: thus, the second fluid contained in the frame 16 is also located inside the sleeves 48.

We will now describe the operation of this device with reference to FIGS. 2 and 3. In a first embodiment, the electromagnet 42 is permanently excited and therefore attracts the head 40 of the plunger 36, which causes the rocker 28 and the pusher 18 are held in the locking position. When we want to drop ballast, we cut the power to the electromagnet 42 which therefore ceases to attract the plunger 36. Under the effect of the spring 44, it is pushed to the right of Figure 2 and arrives in the position illustrated in FIG. 3. The rounded part 46 of the rocker 28 is no longer maintained and the latter can pivot around the axis 30. This pivoting has the effect of lifting the rounded part 32 which is no longer in contact with the abutment face 34 of the pusher 18. The latter can therefore move under the action of the spring 22 and control a mechanism which is not shown in FIGS. 2 and 3. Thus one arrives at the final position illustrated in FIG. 3 in which the pusher 18 and the plunger 36 have moved to the right of the figure while the rocker 28 has pivoted anticlockwise as seen in FIG. 2.

Note that this also had the effect of displacing the flexible skirt 26 and offering in this part of the device a greater space for the fluid contained in the frame 16. At the same time, the flexible sleeves 48 are crushed under the effect of sea water pressure. In fact, it can be seen in FIGS. 2 and 3 that the sleeves 48 are located inside a compartment 52 communicating with the ambient medium through openings such as 54. Thus, the pressure of seawater has the effect of crushing the sleeves 48 so that the volume available for the fluid contained inside the frame 16 constantly adapts to pressure variations due to the ambient environment.

It can also be seen that a number of conduits 56 have been provided which act as dash-pots, the diameter of which has been determined in order to control the speed of the second fluid when the device is put into operation, that is to say when the skirt 26 is deployed and the sleeves 48 are crushed: it is thus possible to control the force with which the pusher 18 acts on the elements which it has to move. Apart from the use of this device on board an underwater vehicle where the arming is carried out outside the first fluid by compressing the piston by an appropriate means, the arming can be carried out using a device incorporated into the device.

Figure 4 illustrates one of these devices. A screw-nut system is used to return the pusher 18 to the locked position once the system has operated. This device consists of a micromotor 58, fixed relative to the frame 16, and controlling a threaded rod 60 movable in rotation and immobilized in translation. A nut 62, immobilized in rotation but free in translation, can move along the rod 60. The nut 62 carries a rocker 64 movable in rotation about an axis 66 carried by this nut 62, the rocker 64 being stressed towards the rod 60 by a spring 75. The rocker 64 also carries a pawl 68 movable in rotation about an axis 70 carried by the rocker, the pawl 68 being able to come into contact with a pawl stop 72. It should be noted that the pawl 68 is free, its stroke being limited by the stop 72. In its starting position, the rocker 64 is located in the vicinity of the micromotor 58 and is in the raised position thanks to a stop 74 controlled by the motor. When the pusher 18 has operated, it is in position 18a (FIGS. 3 and 4), that is to say on the right side of FIG. 4. When it is desired to return it to the locking position, it is started. the motor 58, which has the effect on the one hand of erasing the stop 74 and of bringing the rocker 64 in a horizontal position, and on the other hand of rotating the rod 60. The nut 62 therefore moves towards the right of the figure to position 62a shown schematically in phantom. During this movement, when the pawl 68 meets the external face of the rear part 20 of the pusher 18, it switches anticlockwise as seen in FIG. 4, then returns to its normal position when it is located opposite an orifice 76 provided in part 20 of the pusher 18. The pawl 68 is then in contact with one of the faces of this orifice and the motor 58 is started so as to bring the pusher 18 back from position 18a in the locked position. At this moment, the nut 62 has returned to its starting position and the control of the stop 74 has the effect of rotating the rocker 64 clockwise as seen in FIG. 4. The pawl 68 is then extracted from the orifice 76 and no longer hinders the movement of the pusher 18 during the next start-up thereof.

FIG. 5 illustrates a variant in which the rocker 28 of FIG. 2 is replaced by a set of balls 80 movable inside a housing 82. The end balls 84 and 86 play the same role as the rounded parts 32 and 46 of rocker 28 respectively. The balls 80 can either be embedded in a flexible material such as rubber, or are free to move inside the housing 82. In order to prevent the end balls 84 and 86 from escaping, provision has been made for stroke of the pusher 18 sufficiently short that its rear part prevents the ball 84 from falling while the ball 86 is retained by a stop 88.

Finally, in the example of FIG. 6, the pivoting rocker 28 of FIG. 2 is replaced by a free rocker 90, which comprises at its two ends rounded parts 92 and 94 which play the same role as the rounded parts 32 and 46 of the rocker 28 of Figure 2. The rocker 90 is a free rocker, that is to say that it is not mounted on a fixed axis like the rocker 28 but can move freely inside its housing when the device is started. However, as in the case of Figure 5, the stroke of the pusher 18 and the plunger 36 and the shape of the housing of the rocker 90 are determined so that it does not escape.

Thus, the device which is the subject of the invention has interesting advantages since it is simple to produce and of safe and reliable operation. In addition, it involves a limited mechanical action determined by the calibration of the springs 22 and 44 and by the diameter of the conduits such as 56. On the other hand, the fact that the entire mechanism is located inside d A sealed frame filled with fluid avoids all the problems due to corrosion and turbidity of the ambient environment. Finally, the presence of the skirt 20 and the sleeves 48 means that the interior space of the frame 16 is permanently completely filled with a fluid, the pressure of which automatically adjusts to that of the surrounding medium. It is thus possible to work at any depth, that is to say either close to the surface with low pressure, or in the deep seabed (of the order of 11,000 meters for the largest ocean trenches) where the pressure is very high.

Finally, it is understood that the invention is not limited to the single embodiment which has just been described, but that it is possible to envisage variants without thereby departing from the scope of the invention. For example, the operation of the device has been described in the case where the electromagnet is permanently energized, the interruption of the supply causing the plunger 36 to detach from the electromagnet 42. However, this would not go beyond the scope of the invention using a reverse system where the electromagnet comprises a coil which attracts the head 40 of the plunger 36 thanks to its permanent magnetization, this magnetization being canceled when the coil is energized. Finally, it would not go beyond the scope of the invention using other systems than that described in FIG. 4 to return the pusher to the locked position or by using other systems than balls or rockers to keep the pusher in the locked position.

Claims (10)

1. Actuator usable in a fluid under a high pressure, called the «first fluid», of the type having a plunger (18) which is mobile with respect to a structure and connected thereto by elastic means (22), as well as means (28) for locking the plunger (18) with respect to said structure, characterized in that at least part of the plunger (18), the elastic means (22) and the locking means (28) are located within the closed frame (16) containing a second fluid and in that the actuator has means (26, 48) enabling the pressure of the second fluid in the frame (16) to constantly adapt to that of the first fluid.

2. Actuator according to claim 1, characterized in that the means enabling the pressure of the second fluid to constantly adapt to that of the first fluid incorporate a flexible skirt (26) having a first end tightly fixed to the mobile plunger (18) and a second end tightly fixed to the frame (16), said flexible skirt (26) separating the first and second fluids and at least one deformable sleeve (48) tightly fixed to the frame (16) and whose interior communicates with the space within the frame (16), said sleeve (48) separating the first and second fluids and being able to deform under the effect of variations in the pressure of the firstfluid.

3. Actuator according to either of the claims 1 and 2, characterized in that the space within the frame (16) has at least one partition traversed by a pipe (56) permitting the passage of the second fluid, the diameter of said pipe (56) determining the force exerted by the plunger (18) during the operation of the actuator.

4. Actuator according to any one of the claims 1 to 3, characterized in that the plunger (18) locking means comprise a locking member (28) mobile between a plunger (18) locking position and a plunger (18) unlocking position, an electromagnet (42) and a ram (36) mobile within the frame (16) and connected thereto by elastic means (44), whereby said ram (36) can come into contact with the electromagnet (42) and cooperates with the locking member (28) so as to maintain the latter in the locked position when the ram (36) is in contact with the electromagnet.

5. Actuator according to claim 4, characterized in that the locking member is a rocking lever (28) mobile in rotation about a spindle (30) fixed with respect to the frame (16).

6. Actuator according to claim 4, characterized in that the locking member is a free rocking lever (90),

7. Actuator according to claim 4, characterized in that the locking member is constituted by a plurality of balls (80) mobile within a recess (82) provided in the frame (16).

8. Actuator according to any one of the claims 4 to 7, characterized in that the electromagnet (42) only produces a magnetic field when an electric current passes through it.

9. Actuator according to any one of the claims 4 to 7, characterized in that the electromagnet (42) has a permanent magnetization coil, the magnetization being cancelled out by a current passing through the coil.

10. Actuator according to any one of the claims 1 to 9, characterized in that it also has a nut-screw system (60, 64) controlled by a motor (58) for returning the plunger (18) to the locked position.

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