FR2642223A1 - IMPROVED SOLENOID ACTUATOR - Google Patents

Abstract

A solenode actuator having a moving part 28 associated with a permanent magnet 40. When the electromagnet 12 is put to work, the electromagnet 12 pushes the permanent magnet 40 away, moving the permanent magnet 40 away from the part. movable 28 to put it in a second position, under the influence of a mass of ferro-magnetic material 42 in the form of a cup which is placed next to the second position. In a preferred embodiment, the poles of the permanent magnet 40 of the moving part 28 are aligned coaxially with the winding 14 and the core of the electromagnet 12. In another embodiment, the mass of ferro-magnetic material 42 can be omitted and the actuator can be provided with magnets or tandem windings.

Description

1 -

IMPROVED SOLENOID ACTUATOR

  This invention relates to solenoid actuators for switches and the like

electrical appliances.

  Although much progress has been made recently in the technology of fully electronic switching devices, electromagnetic actuators are still needed in many applications for which fully electronic devices are not suitable. Consequently, there is a need for reliable electromagnetic actuators, in particular in applications where the apparatus is subjected to vibrations, to strong shocks, to high accelerations as well as to variable temperatures and humidity.

  In the past, electrical switchgear

  which, like the relays, could withstand this difficult environment often had a complex internal structure. As a result, many of these old devices are expensive and difficult to manufacture. For example, a typical old relay is a 412 K Series TO-5 model manufactured by Teledyne Corporation. This relay consists of a clamp armature comprising two small pushers and an insulating glass bead which pushes a relay blade, from a first position to put it in a second position, when the electromagnetic force attracts the armature and a large return spring to return the armature to its first position when the electromagnet is put to rest. The construction of the frame as well as the complex arrangement of the contact elements make this relay difficult to manufacture. This model is also characterized by a relatively high number of moving parts and welded joints which can break down. Consequently, the reliability of this relay limits its 2 -

  useful in many applications.

  In another earlier model, the system consisting of the spring and the armature is replaced by a sliding actuator in the form of a bar mechanically coupled to the contact blade. The moving part is equipped with a remote permanent magnet which is usually attracted towards the stirrup and the core of the electromagnet. Thus, the moving part and the contact blade are held in a first position. Putting the electromagnet to work repels the permanent magnet, which has the effect of moving the moving part and the blade to put them in a second position. Although this model is an improvement compared to the T0-5 relay mentioned above, it has only one stable position and it consumes a lot

  of energy to repel the permanent magnet.

  In another model, a frame made of a

  ferro-magnetic material is placed under an electro-

  magnet. To increase resistance to shock and vibration, a permanent magnet is placed so that the armature is held in a position

  by the force of attraction of the permanent magnet.

  When the electromagnet of the actuator is put to work, the force of attraction of the electromagnet becomes stronger than that of the permanent magnet and the armature is brought to a second position. This model also consumes substantial energy

to overcome the permanent magnet.

  According to yet another design, an armature coupled to movable conductors slides coaxially in the core of the electromagnet coil. The magnetic field of the electromagnet, when excited exceeds the force of attraction of a permanent magnet

  fixed, moving the frame and the movable conductor.

  This arrangement also consumes substantial energy. - 3 - An object of the present invention is to provide an improved solenoid actuator which, in practice, makes it possible to avoid the limitations mentioned above,

  in particular thanks to a relative mechanical mounting

  uncomplicated. Another object of the invention is to provide a solenoid actuator which is both very reliable, of simple construction, relatively inexpensive to manufacture and capable of withstanding the environmental conditions typical of applications requiring

such actuators.

  An actuator according to a preferred embodiment of the present invention consists of a movable part provided with a permanent magnet placed coaxially under the core of an electromagnet. The moving part is coupled to the element to be actuated and is held in a first position by the force of attraction of the permanent magnet on the electromagnet. When the electromagnet is put to work, it pushes back the permanent magnet, moves the moving part and the actuated element to put it in a second position. In a preferred embodiment, the actuator

  also consists of a mass of ferro-

  magnetic cup-shaped, placed next to the second position. When the electromagnet is put to work, the attraction of the permanent magnet of the moving part on the ferro-magnetic mass combines with the repulsive force of the electromagnet to move the moving part and put it to the second position. The cup-shaped mass is made of a material

  magnetic, to close the magnetic circuit.

  We have realized that this arrangement reduces the importance of the repulsive force that the electromagnet must provide and therefore results in a reduction in the

  power consumption of the actuator.

  - 4 - In another embodiment, the moving part can also include a frame magnetically coupled to the permanent magnet of the moving part. The armature also participates in the closing of the magnetic circuit when the permanent magnet is in the second position, next to the ferro-magnetic mass. Similarly, when the permanent magnet is in the first position, next to the electromagnet core, the armature participates in the

  closing of the electromagnet's magnetic circuit.

  In another embodiment, the actuator can have permanent magnets in tandem aligned coaxially with the core of the electromagnet, as it appears in the illustrated embodiment. These permanent magnets can be coupled to each other in order to move in tandem, between the first position and the second

  position, and depending on the direction of the field of the electro-

  magnet. A moving part coupled to one of the permanent magnets activates the moving conductor, in accordance with the movement of the magnets. This assembly can be

  bistable type with locking or monostable.

  Alternatively, one of the permanent magnets can be removed to allow the system to work in

monostable.

  In another embodiment, a permanent magnet can be placed between coaxially aligned windings and adapted to move between these two windings. By suitably exciting the windings, in order to produce the desired magnetic fields, the permanent magnet and a moving part coupled to the permanent magnet can be actuated, between first and second positions, in bistable or in

monostable, as appropriate.

  The other advantages as well as the structure of the invention will be better understood by reading the

  detailed description which follows as well as the drawings

joints.

- 2642223

  - 5 - Figure 1 is a section of a solenoid actuator according to an embodiment of the present invention, and illustrating the position of the moving part

  when the electromagnet is at rest.

  Figure 2 is a section of the actuator of Figure 1, illustrating the position of the moving part

  when the electromagnet is at work.

  Figure 3 is a section of an actuator according to another embodiment, it illustrates the position of o10 the moving part and the electromagnet when this

the latter is at rest.

  Figure 4 is a section through a lockable bistable actuator which conforms to another embodiment

  equipped with a couple of tandem magnets.

  Figure 5 is a section of an actuator according to another possible embodiment and having a single permanent magnet, illustrating the position of the part

  mobile when the electromagnet is at rest.

  Figure 6 is a section through a bistable locking actuator according to another embodiment

  alternative fitted with tandem windings.

  Figures 1 and 2 show a solenoid actuator 10 according to a preferred embodiment of the present invention. Illustrated in section, the actuator 10 25 is practically symmetrical (round) with respect to the central axis A-A. Actuator 10 can be used to

  operate any number of electro-

  mechanical like HF and DC relays as well as flexible reed switches and HF attenuators,

  power dividers and more.

  The actuator 10 consists of an electromagnet 12 composed of a winding of conductive wire 14 wound around a coil of cylindrical shape (not shown). Centered in the winding 14 is a core 18 made of a ferromagnetic material. The magnetic circuit is completed by a bracket 20 or

  cylinder head also made of ferro-magnetic material.

  The actuator 10 actuates a moving part like the carrying member 22 of FIG. 1 which illustrates a first position (open position). The conductive strip 22 can be moved to come into contact with fixed contacts 24 in order to define a

  second position (closed) (Figure 2).

  To actuate the conductive blade (or another mobile element) of a relay or of another electrical device, the actuator 10 also has a movable cylindrical part 28 adapted to move in an opening 32 of the body 34 of the actuator . In the illustrated embodiment, the outer surface of a finger 36 of the movable part 28 and the inner surface of the opening 32 are of cylindrical shape, the outside diameter of the finger 36 being slightly smaller than the inside diameter of the opening 32, in order to allow free axial movement of the moving part 28 in the opening 32. Of course, it is obvious that the moving part 28 can also have

other forms.

  The finger 36 couples the moving part 28 to the movable element to be actuated. In the illustrated embodiment, the finger 36 is made of a non-magnetic insulating material so that the finger 36 can, if necessary, directly engage electrically conductive elements,

for example flexible blades.

  A permanent magnet 40 is integrated in an upper insulated part 39 of cylindrical shape of the moving part 28. In an illustrated embodiment, the magnet 40 is preferably a raw material, for example cobalt samarium, neodymium iron or neodymium iron. boron. The horizontal section of the magnet 40 is square, but other shapes, for example a rounded shape, can also be used. As it appears by locating the symbols "N" 'and "S" the north and south poles of the magnet 36 are aligned coaxially with the central axis AA of the winding and the core of the electromagnet of the actuator. When the winding 14 of

  the electromagnet 12 is no longer energized, that is to say

  say is put to rest, the permanent magnet 40 is attracted by the core 18 of the electromagnet 12, bringing the moving part 28 to the "first" position.

  the actuator 10, as it appears in FIG. 1.

  Thus, the movable element coupled to the movable part 28 by the finger 36 of the movable part, is maintained in a "first" position which corresponds to the first position of the movable part which is illustrated in the

figure 1.

  When energized, the electromagnet exerts a coaxial electromagnetic force on the permanent magnet 40 of the moving part 28, pushing the permanent magnet 36 relative to the core 18 of the electromagnet and moving the moving part 28 axially to bring it to the "second" position illustrated in FIG. 2. To further reduce the magnitude of the repulsion force (and therefore the electrical energy) required by the electromagnet, the actuator 10 of the illustrated realization includes

  also a mass or stirrup 42 of ferro- material

  soft magnetic, for example iron, placed next to the second position of the moving part 28. The permanent magnet 40 of the moving part 28 is attracted towards the ferro-magnetic mass 42 and this force of attraction

  combines with the repulsive force of electro-

  magnet to move the moving part and bring it to the second position in FIG. 2. In this way, the moving element coupled to the moving part 28 by the

  finger 12 is put in a second position (closed).

- 8 -

  In the illustrated embodiment, the ferro-

  magnetic 42 has the general shape of a cup and is centered relative to the central axis A-A. The section of the mass 42 has the shape of an "IU ', it comprises a basic position 44 and a raised wall position 48. This shape should improve the closing of the

  magnetic circuit of the permanent magnet 40.

  Of course it is quite possible that the mass 42 has other forms. In one embodiment, the ferromagnetic mass 42 is dimensioned and placed so that, in the second position of FIG. 2, the force of attraction of the permanent magnet 40 on the core 18 and the stirrup 20 of the electromagnet 12 either

  greater than the force of attraction on the ferro- mass

  magnetic 42. Consequently, when the electromagnet is put to rest, the moving part 28 returns to the first position illustrated in FIG. 1. In this arrangement, the actuator 10 is considered to be

  "normally" open at the first position.

  Alternatively, the size of the ferro-

  magnetic 42 can be increased so that the attraction of the permanent magnet 40 for the ferro-magnetic mass 42 is greater than the attraction for the core 18 and the stirrup 20 of the electromagnet when the moving part 28 is in the second position of FIG. 2. Consequently, when the electromagnet is put to rest, the

  moving part 28 remains in this second position.

  To bring the moving part 28 back to the first position in FIG. 1, the electromagnet can be returned to work, the current passing through the winding 14 being reversed, thus causing the poles of the electromagnet to be reversed. As a result, the permanent magnet 40 of

  the moving part 28 is also attracted towards the electro-

  magnet by the electromagnetic force exerted by the electromagnet, overcoming the attraction of

  the permanent magnet 40 on the ferro-magnetic mass 42.

  -9- Depending on the dimensions and the respective distances of the core 18, the stirrup 20 and the stirrup 42, this actuator can function as a switch

  normally open or normally closed.

  Preferably, the range of admissible movements of the movable element coupled to the movable part 28 is limited so that the permanent magnet 40 of the movable part 28 cannot come into contact with the core of the electromagnet 12 when the movable part is at the first position in FIG. 1. This arrangement also reduces the amount of energy required to move the movable part 28 later in order to bring it to the second position in FIG. 2. In a similar manner, the second position of the movable part 28 of FIG. 2 can be defined by limiting the possibilities of displacement of the movable element towards its second position. For example, a movable element such as a flexible blade can bear alternately on two contact terminals which define the first and second positions and,

  there the interval of movement of the flexible blade 40.

  Since the moving part 28 is coupled to the conductive blade by the sliding finger 36, the first and the second position of the movable part are defined by the first and the second position of the conductive blade. Consequently, the actuator 10 adjusts itself. In other words, the moving part 28 always moves the conductive blade so that it actually bears on one of the two contact terminals, ensuring a good electrical connection between the blade

conductive and the associated terminal.

  In addition, the actuator can selectively be made monostable, in its first position or in its second position, by appropriately setting the authorized attraction of the permanent magnet between on the one hand the upper bracket 20 and the core 18 and,

- 10 -2642223

  on the other hand, the lower bracket 42. Thus, for example, the actuator 110 of FIG. 3 locks in the second position (normally closed) since the distance 8 between the armature 158 and the lower bracket 142 is much smaller than the distance between

  armature 158 and upper bracket 120.

  It should also be noted, from the above, that the actuator 10 has only one movable part, the movable part 28, apart from the movable element which is actuated. The minimum number of moving parts means that the reliability of the actuator 10 is increased. In addition, the ease of manufacture is itself increased and also includes a corresponding reduction in the cost price. Even more, it appears that the actuator 10 of the illustrated embodiment is capable of working at higher speeds than many old actuators. The simplicity of the design also ensures high resistance to degradation caused by extreme environmental conditions such as shock, acceleration, vibration, variations in the

temperature and humidity.

  Similar advantages can be obtained by the other embodiments described in Figures 3 to 6. Figure 3 illustrates an actuator 110 similar to the actuator 10 of Figures 1 and 2, except that the actuator 110 is equipped with an armature 150 coupled

  to a permanent magnet 140 of the moving part 128.

  The frame 140 has the general shape of a disc, it defines a central opening 152 sized to allow the admission of the extension 154 of the core of the electromagnet 118. As it appears in FIG. 3, the armature 150 comprises a roughly cylindrical part 156 coupled to the magnet 140 coaxially aligned and a roughly flat part 158 which extends between the stirrup 142 of the moving part 128 and

- 11 -

  the stirrup 120 of the electromagnet 112. The armature 150 of the illustrated embodiment has a shape which facilitates the closing of the magnetic circuit by the permanent magnet and the stirrup 142 of the moving part 128 when the moving part 128 (and the movable element 122) are in the second position illustrated in FIG. 2. Conversely, when the movable part 128 is in the first position next to the core 118, the armature 150 participates in the realization of the magnetic circuit of the electromagnet 112. This arrangement also leads to a reduction in the energy consumed and an increase in reliability. It is recognized that the caliper 150 can also

have other forms.

  In the illustrated embodiment, the space 160 which is between the movable element 122 and the body 134 is preferably less than the space 162 which separates

  the armature 150 and the core and the stirrup of the electro-

  magnet 112. This ensures that the movable element 122 comes into contact with the body 134 before the armature 158 can come into contact with the electromagnet 112, which prevents the existence of real contact between the armature 158 and the stirrup 120. This arrangement reduces the force necessary to magnetically disengage the permanent magnet 140 from the core and the stirrup from the electromagnet when the moving part 128 is brought back from the first position to the second position. illustrated in Figure 3. Similarly, the contacts 124 are positioned to allow the existence of an interval

  163 between the frame 158 and the lower bracket 142.

  Figure 4 shows another possible embodiment characterized by two permanent magnets 340 and 364 in tandem. The permanent magnet 340 is fixed to one end of a moving part 328 similar to the moving part 28 in FIG. 1. The magnets 340 and 364 are held at a predetermined distance from one another, by a rod 366 of non-ferromagnetic material which is

- 12 -

  adapted to slide in a central opening 368 of the core 318 of the winding 314 of an electromagnet 312. As it appears in FIG. 4, the magnetic poles of the permanent magnets 340 and 364, the opening 368 of the core 318 and the rod 366 are

aligned coaxially.

  FIG. 4 illustrates the actuator 310 in the second position in which the movable element 322 engages the fixed contacts 324 (closed position). To bring the movable member 322 to the first position (open position), the winding 314 is energized to produce a magnetic field which repels the permanent magnet 364 and attracts the permanent magnet 340. If the movable member 322 allows the permanent magnet 340 to approach fairly close to the core 318 of the electromagnet 312, the actuator 310 "locks" in the first position, even after the winding 314 has been put to rest . To bring the movable element 322 to the second position illustrated in FIG. 4, the winding 314 is excited in the opposite direction, in order to produce a magnetic field which repels the permanent magnet 340 driving the movable part 328 and the movable contact 322 so that there is engagement with the fixed contacts 324. In the illustrated embodiment, a space is preferably provided between the non-magnetic material 369 which is

  found around the permanent magnet 364 and the electro-

  magnet 312, to ensure good contact between the movable element 322 and the fixed contacts 324 in the second

position.

  It can be seen that the central rod 366 does not necessarily have to be physically coupled to the permanent magnet 340 or 364. Since the rod 366 can only move in coaxial translation in the core 318 of the electromagnet 318 of the illustrated embodiment, fixing the permanent magnets to the rod

- 13 -

  366 also provides coaxial guidance of the magnets

permanent and moving parts.

  The operation of the actuator 310 has been described above as that of a bistable locking actuator. Of course, it can be seen that this operation can be modified to become monostable, so that the locking is done only at the first or at the second position, by adjusting for this the space which has been left between the permanent magnets and the electromagnet, to produce a

  imbalance between the respective forces of attraction.

  For example, actuator 310 can be configured as a normally closed actuator, limiting the

  displacement of the permanent magnet 340 towards the electro-

  magnet 312 so that, in the first position, the attraction of the permanent magnet 364 on the core 318 is greater than that of the permanent magnet 340 on the core 318, when the winding 314 is put to rest. Consequently, the actuator 310 automatically returns to the second position (normally closed position) illustrated in FIG. 4, from the first position, when the winding is put

at rest.

  Figure 5 illustrates an embodiment which is similar to the embodiment of Figure 4 but in which one of the permanent magnets in tandem has been removed. Thus, the actuator 410 of FIG. 5 is equipped with a permanent magnet 470 on one side of the core 418 with a winding 414 of an electromagnet 412 and

  a moving part 428 on the other side of the core 418.

  As shown in FIG. 5, the moving part 428 has no permanent magnet and is coupled to the permanent magnet 470 which is located on the other side of the core 418, by a rod 466 similar to the rod 366 of Figure 4. The actuator 410 of Figure 5 is monostable in the second position (that is to say the

- 14 - 2642223

- 14 -

  closed position) illustrated in Figure 5.

  The excitation of the winding 14 produces a magnetic field which repels the permanent magnet 470 by attracting the rod 466 and the moving part 428 with the permanent magnet 470, then causing the disengagement of the mobile element 422 from the contacts. fixed 424. When the winding 414 is de-energized, the permanent magnet 470 returns the rod 466, the movable part 428 and the movable contact 422 to their respective positions

illustrated in figure 5.

  FIG. 6 illustrates another possible embodiment which, in practice, combines two actuators similar to the actuator 410 of FIG. 5, in order to obtain a locking actuator 510 of the bistable type. Also, the actuator 510 has two coaxial electromagnets 512 and 572 coupled by a sleeve 574 made of non-magnetic material. Between the two electromagnets 512 and 572, there is a pair of permanent magnets 570 and 576 whose poles are coaxially aligned respectively with the windings 518 and 578 of the electromagnets 512 and 572. It is obvious that this actuator can be equipped with a single magnet, but it appeared that this realization is a little easier to manufacture with the

  two elements which are represented in the figure.

  In the illustrated embodiment, the magnets 570 and 576 are guided between the first position and the second position by two guide rods 566 and 580 which are adapted to ensure a sliding translational movement in the coaxial openings of the cores 518 and 582 of the electro- magnets 512 and 572. Figure 6 shows the actuator 510 in the first position for which the movable contacts 522 are released from the fixed contacts 524. To actuate the movable contacts 522 in order to put them in the second position (closed), the winding higher 578 can be excited to produce a magnetic field that repels

- 15 -

  magnets 570 and 576 to the lower winding 514 until the movable contacts 522 engage

  the fixed contacts 524 in the second position (closed).

  When the upper winding 578 is put to rest, the actuator 510 remains in the second position (locked) if the attraction of the magnets 570 and 576 for the core 518 of the lower electromagnet 512 is greater than that of the magnets for core 582 of

the upper electromagnet 572.

  When it has been locked in this second position, the actuator 510 can be brought back to its first position by exciting the lower electromagnet 512 which produces a magnetic field repelling the magnets 570 and 576 towards the core 582 of

  the electromagnet 572, as it appears in figure 6.

  Here, the actuator 510 remains locked in its first position if the attraction of the magnets 570 and 576 for the core 582 of the upper electromagnet 572 is stronger than the attraction of the magnets for the core 518 of the electro lower magnet 512. Although the operation described for the actuator 510 is that of a bistable locking device, it is obvious that the actuator 510 can work in monostable mode by unbalancing the magnetic forces of attraction. In addition, the windings can be put to work one at a time or together, depending on the needs of the intended application. Of course, many modifications can be made to the present invention, in its various aspects, and these variants will be obvious to those who are familiar with this technique, some only becoming apparent after study and others being

  than usual aspects of electro-

  mechanical. For example, sizes and shapes other than those described may be used. Other modifications and variations are also possible,

- 16 -2642223

  each specific design depending on a particular application. Consequently, the field of the invention must in no case be limited by the particular embodiments described above, it must

  on the contrary be defined by the claims which

follow and their equivalents.

- 17 -

Claims (32)

CLAIMS:   1. A solenoid actuator characterized in that it is composed of: a winding (314) with a core (318); a first permanent magnet (340) disposed on one side of the core (318) and movable between a first position and a second position; a second permanent magnet (364) disposed on the other side of the core and movable between the first position and the second position; and a conductor (322) coupled to one of said magnets and movable between the first and second positions. in which the working of the winding (314) produces an electromagnetic field which causes the displacement of the first magnet (340) and the second magnet (364) which will go to their second position respectively, causing the displacement of the   conductor (366) which moves to its second position.   2. The solenoid actuator according to claim 1 characterized in that the first magnet is spaced from the   second magnet from a predetermined distance.   3. The solenoid actuator according to claim 2 characterized in that it also comprises a rod   (366) separating the first magnet from the second magnet.   4. The solenoid actuator according to claim 3 characterized in that the rod (366) is coupled to the   first (340) and second (366) magnets.   5. The solenoid actuator according to claim 1 characterized in that the first magnet (340) and the second magnet (364) can only move in translation between the first position and the second position. 6. The solenoid actuator according to claim 2 characterized in that the core (318) defines a cylindrical opening in which the rod (316) is - 18 -   adapted to move in translation between the   first position and second position.   7. The solenoid actuator according to claim 1 characterized in that it also comprises a passage (368) and a movable part (366) adapted to move in translation in the passage, between the first position and the second position, said movable part being provided with one of said permanent magnets (340, 364) at one of its ends and carrying, so   insulator, the conductor (322), at its other end.   8. The solenoid actuator according to claim 3 characterized in that the rod (366), the core (318) and the poles of the permanent magnets are aligned coaxially. 9. A solenoid actuator characterized in that it comprises: a winding (314) having a core (318) defining a centrAl passage (368) coaxial; a rod (366) adapted to move in translation in the central passage (368), between a first position and a second position; a first permanent magnet (364) disposed on one side of the core (318), fixed to the rod (366) and movable between the first and second positions, the magnetic poles of said first permanent magnet (364) being aligned coaxially with the winding core; a movable part (328) at the end of which a second permanent magnet (340) is fixed, then with a coupling at the other end of the rod (366), said second permanent magnet (340) having its magnetic poles aligned coaxially with the core and the magnetic poles of the first permanent magnet; and a conductive blade (322) insulatively coupled to the other end of the moving part (328) and movable between the first position and the second   position, according to the movements of the moving part. - 19 -   10. A solenoid actuator characterized in that it comprises: a permanent magnet (40, 140, 470) movable between a first and a second position; a winding (14, 114, 414) having a core (18, 118, 418) disposed adjacent to the first position of the magnet (40, 140, 470) and aligned coaxially with the movements of the magnet; a cup-shaped stirrup (20, 120, 420) made of a magnetically permeable material (42, 142), next to the second position of the permanent magnet and aligned coaxially with the core; and a conductor (36, 466) coupled to the permanent magnet (40, 140, 470) and movable between the first position and the second position, according to the movements of the permanent magnet; wherein the working of the winding (14, 114, 414) produces a magnetic field which moves the magnet (40, 140, 470) to its second position,   to bring the driver to his second position.   11. A solenoid actuator for moving a movable element (22, 122, 422), characterized in that it comprises: a movable part (28, 428) with a permanent magnet (40, 140, 470), the movable part being coupled to the movable member (22, 122, 422) and being placed in the first position, said movable part (28, 428) and said movable member (22, 122, 422) being movable between said first position and a second position; -   an electromagnet (10, 110, 410) whose core (18, 118, 418) is placed so as to attract the permanent magnet (40, 140, 470) from the moving part (28, 428) up to the first position and to push the permanent magnet (40, 140, 470) of the moving part when the electromagnet (10, 110, 410) is put to work; and - 20 -   a mass (20, 120, 420) of ferro- material   cup-shaped magnetic placed next to the second position and aligned coaxially with the core (18, 118, 418) and the permanent magnet (40, 140, 470) and adapted to receive and attract the permanent magnet; wherein the moving part (28, 428) is brought to the second position by the repelling force of the permanent magnet (40, 140, 470) of the moving part when the electromagnet (10, 110, 410) is put at   work and by the force of attraction of the ferro- mass magnetic (14, 114, 414).   12. The actuator according to claim 11 characterized in that the mass (14, 114, 414) of ferro-magnetic material is not of sufficient size to maintain the permanent magnet (40, 140, 470) of the part movable (28, 428) in the second position after the electromagnet (10, 110, 410) has been put to rest.   13. The solenoid actuator according to claim 11, characterized in that the movable element (22, 122, 422) is a flexible blade.   14. The solenoid actuator according to claim 11 characterized in that the ferro-magnetic mass (14, 114, 414) is centered around the path of the magnet   permanent (40,140,470) of the moving part.   15. The solenoid actuator according to claim 14 characterized in that the ferro-magnetic mass (414) defines a central opening in which the moving part (466) can slide.   16. The actuator according to claim 11 characterized in that it also comprises an armature (150) supported by the movable part (360) and magnetically coupled to the permanent magnet (140), said armature (150) being positioned so as to close the magnetic circuit with the electromagnet (110), when the permanent magnet (140) is in the first position, and to close the magnetic circuit with the electromagnet (110) when '' permanent magnet (140) is in second position.   17. The actuator of claim 16 characterized in that the armature (150) has the general shape of a disc and extends above the mass in the form of section (120).   18. An actuator for actuating an element   mobile (22) characterized in that it comprises: -   a movable part (28) with a permanent magnet (40), the movable part (28) being coupled to the movable element (22) and being disposed in a first position, said movable part (28) and said movable element (22 ) being movable in translation between said first position and a second position; an electromagnet (10) having a core (18) aligned coaxially with the poles of the permanent magnet (40) of the moving part (28) to attract the permanent magnet (40) of the moving part to the first position and to repel the permanent magnet of the moving part using a magnetic field when the electromagnet (10) is at work, in order to bring the permanent magnet (40) of the moving part in the second position; and a stirrup (46) of ferro-magnetic material in the form of a cup, placed next to the second position of the magnet (40).   19. A solenoid actuator characterized in that it comprises: a winding (414) with a core (418); a first permanent magnet (470) disposed on one side of the core (418) and movable between a first position and a second position; and a conductor (422) disposed on the other side of the core and coupled to said magnet (470) and movable between the first position and the second position; - 22 -   wherein putting the winding (414) to work produces an electromagnetic field which moves the magnet (470) to its second position, also causing the conductor (422) to move to its second position. 20. The solenoid actuator according to claim 19 characterized in that the magnet (470) and the contact   mobile (422) are spaced a pre-   determined. 21. The solenoid actuator according to claim characterized in that it also comprises a rod (466) disposed in the core (418) of the winding (414) and coupling the magnet (470) and the movable contact (422).   22. The solenoid actuator according to claim 19 characterized in that the magnet (470) can only move in translation between the first position and the second position.   23. The solenoid actuator according to claim 21 characterized in that the core (418) defines a cylindrical opening in which the rod (466) is adapted to move in translation between the   first position and second position.   24. The solenoid actuator according to claim 19 characterized in that it also comprises a passage in its core (418) and a movable part (428) -adapted to move in translation in said passage, between the first and the second positions, said movable part (428) being provided with said permanent magnet (470) at one of its ends and carrying   isolated conductor (422) at its other end.   25. The solenoid actuator according to claim 23 characterized in that the rod (466), the core (418) and the poles of the permanent magnet are aligned coaxially.   26. A solenoid actuator characterized in that - 23 -   that it comprises: a winding (414) having a core (418) defining a central coaxial passage; a suitable rod (466). to move in translation in the central passage, between first and second positions; a permanent magnet (470) disposed on one side of the core (418), fixed to one end of the rod (466) and movable between the first position and the second position, the magnetic poles of said permanent magnet being aligned coaxially with the core (418) of the winding (414); a conductive strip (422) insulatingly coupled to the other end of the rod (466) and movable between the first position and the second position, in accordance with the movements of the magnet (470).   27. A solenoid actuator characterized in that it comprises: a first winding (514) with a core (518); a second winding (578) with a core (582); a first permanent magnet (570, 576) disposed between the cores and movable between first and second positions; and a conductor (522) coupled to said magnet (570, 576) and movable between the first and second positions; in which the selective use of   windings (514, 578) produces an electro-   magnetic which brings the magnet (570, 576) to its second position, thus moving the conductor (522) which comes get into its second position.   28. The solenoid actuator according to claim 27 characterized in that the magnet (570, 576) can only move in translation between the first position and the second position. - 24 -   29. The solenoid actuator according to claim 28 characterized in that it also comprises a pair of guide rods (566, 580) coupled to the magnet (570, 576) and in which each core (518, 582) defines a cylindrical opening in which a rod (566, 580) can move in translation between the first position and the second position.   30. The solenoid actuator according to claim 27 characterized in that it also comprises a passage and a movable part (528) adapted to move in translation in the passage, between the first and second positions, said movable part ( 528) carrying a permanent magnet (570, 576) at one of its ends and carrying the conductor in isolation (522) at its other end.   31. The solenoid actuator according to claim 29 characterized in that the rods (566, 580), the cores (518, 582) and the poles of the permanent magnet   (570, 576) are aligned coaxially.   32. A solenoid actuator characterized in that it comprises: a pair of windings (514, 578) each of which has a core (518, 582) defining a central coaxial passage; a pair of rods (566, 580), each rod being adapted to move in translation in an associated central passage, between first and second positions; a permanent magnet (570, 576) disposed between the cores (518, 582), coupled to the rods (566, 580) and movable between the first position and the second position, the magnetic poles of said permanent magnet (570, 576) being aligned coaxially with the cores (518, 582) of the windings; and a conductive blade (522) insulatingly coupled to a rod (566) and movable between the - 25 -   first position and second position, in accordance displacements of the rod (566).