FR2479034A1 - ELECTROMAGNETIC VIBRANT SYSTEM THAT CAN OPERATE AT GREAT AMPLITUDES - Google Patents

Abstract

THE INVENTION RELATES TO AN ELECTROMAGNETIC VIBRATING SYSTEM CAPABLE OF OPERATION AT LARGE AMPLITUDES. THIS SYSTEM INCLUDES A COMBINATION OF ELECTRO-MAGNET 16 AND ARMATURE 14 GENERATING VIBRATIONS AND INCLUDING AT LEAST A FIRST AND A SECOND ELEMENTS DEFINING BETWEEN THEM A GAP 18, A BASE 10 SUPPORTING THE FIRST ELEMENT, A BODY TO BE VIBRATED 12 CONNECTED TO THE SECOND ELEMENT AND A NONLINEAR SPRING DEVICE ASSOCIATED WITH BASE 10 AND WITH THE BODY TO BE VIBRATED 12 AND INCLUDING MEANS ALLOWING TO STORE A NOTABLE ENERGY FROM THE COMBINATION OF ELECTRO-MAGNET AND ARMATURE TO MEASURE THAT IT APPROACH ITS MINIMUM GAP AND CONVERT IT INTO KINETIC ENERGY OF THE ORGAN TO BE VIBRATED. APPLICATION IN PARTICULAR TO SORTING, SIEVING OR TRANSPORT OF BULK MATERIALS.

Description

The invention relates to vibrating systems in general

  and more particularly vibrating electronic systems

  magnetic. Vibrating systems are known and are used in a wide variety of forms for various functions, for example to carry, transport, screen, sort, shake and unload bulk materials. The source of vibration of these systems can be mechanical, such as an electric motor rotating eccentric masses, or hydraulic, pneumatic or electromagnetic. Electromagnetic systems are in favor in most vibrating systems because they allow to use relatively simple and inexpensive constructions, requiring no bearings, in the case of electric motors, joints or valves, as in hydraulic systems and pneumatic tires and they simplify the control

and adjusting the amplitude.

  Despite these advantages, vibrating electronic systems

  Magnetic have a serious inherent flaw that will now be explained: Two types of electromagnetic vibrating structures are commonly used. One uses a movable permanent magnet that passes through an AC coil. This structure, normally used in loudspeakers, is inefficient

  energy wise because it wastes magnetic flux.

  The second commonly used structure employs a reinforcing plate that is drawn abreast by a wound core. This structure avoids inefficiency

  of the movable magnet structure described above.

  above it and is capable of generating relatively large forces. A limitation inherent in this structure # which is commonly used in the manipulation of materials, is that its amplitude is limited by

  the maximum air gap allowed between the armature and the coil.

  The gap is limited by the amount of current that

  can be communicated by the coils of the electromagnet.

  If the air gap is increased, the current is increased accordingly. Thus, for a given air gap, although relatively intense currents can be used and magnetic energies can be drawn from the magnet, the operating current and therefore the energy flow of the magnet are maintained. deliberately weak to prevent the armature from hitting the nucleus when the amplitude reaches the dimensions of the gap. It is therefore understandable that electromagnetic systems are significantly limited in their operation due to limitations

physical of the gap.

  In order to solve this problem, it has been proposed to use an electronic system to decrease the current supplied.

  to the electromagnet as the gap between the electro-

  magnet and the frame decreases. This is not desirable because it decreases the magnetic force and the available energy

  to keep the system moving.

  It was also suggested to use springs

  in combination with electronic systems

  magnets to adjust the vibration of these. It is contrary to the objects of the invention to provide damping springs as this prevents large amplitudes from being reached and this reduces the force and energy available to operate the vibrating system. Therefore, as far as possible, according to the invention, springs having a

relatively small depreciation.

  It is known from US Pat. No. 2,187,717 to use a non-linear spring in association with an electromagnetic vibrating system. The role of this spring in the described system is to regulate the natural frequency of the system and to keep the system close to resonance

  despite the variations of the load.

  The frequency of such a system is given by the expression: frequency = 1 a = f (1) -3- in which c is the stiffness, m being the ratio of the variation of force to the variation of displacement at any point given along the force / displacement curve of a spring. It is thus understood that the constant frequency can be maintained by suitably choosing the amplitude range of a nonlinear spring where there are desired force / displacement characteristics for a given mass. The previously cited US Pat. No. 2,187,717 suggests providing selectable preloading means responsive to mass variation so as to harmonize the force / displacement characteristic with the variable mass and thereby maintain the natural frequency in accordance with equation (1). Variations of the

  frequency of these vibrating systems are undesirable.

  It is also understood that to harmonize the force / displacement characteristic with a variable mass in the manner suggested in the aforementioned US Pat. No. 2,187,717, it is necessary that the non-linearity of the spring be moderate enough to maintain a constant stiffness c in the

  range of system amplitude for any given mass.

  As will be explained below, according to the invention, the stiffness c is not kept constant in the amplitude range of the system. According to one embodiment of the invention, the stiffness c varies by at least twice its magnitude at rest (zero amplitude) and only in the sense of an increase in stiffness when the gap decreases. If the electromagnet only acts on one side of the armature, the non-linearity is only along part of the armature path. On the other hand, the aforementioned US Pat. No. 2,187,717 assures non-linearity.

  along the entire margin of movement of the frame.

  It will also be noted that the non-linear spring of the system according to US Pat. No. 2,187,717 is a highly damping spring due to its great internal friction due to the friction between its blades. On the other hand, the invention

2479034-

  -4- provides springs with low damping characteristics. US Pat. No. 4,235,153 discloses a linear motion electromagnetic force motor using a non-linear spring to counteract an increasing magnetic force so as to stabilize the system. This patent does not describe a vibratory system but rather deals with a positioning apparatus that operates in a DC mode. As a result, it does not address the problem described above, namely the physical shock between a vibrating element entrained by an electromagnet and another element

  in conditions of great amplitude.

  Note in this connection that in a DC system, reducing the gap greatly increases the magnetic force. In an AC vibratory system, it has been found that this increase in force does not occur because, as the air gap closes,

  the inductance opposing the passage of the current increases.

  Thus, vibratory electromagnetic systems present

  a generally constant magnetic force.

  According to one embodiment of the invention, there is provided an apparatus which overcomes the above difficulties and which ensures a large amplitude operation at a power

relatively weak.

  It is therefore proposed, according to one embodiment of the invention,

  an electromagnetic vibratory system characterized in that it comprises a combination of electromagnet and armature generating vibrations and comprising at least first and second elements defining between them an air gap, a base supporting the first element, a vibrating member connected to the second member and a nonlinear spring device associated with the base and the member to be vibrated and comprising means for storing a significant energy of the electromagnet combination and frame as it approaches its minimum air gap and converts it into energy - 5-

  kinetics of the organ to vibrate.

  In addition, according to one embodiment of the invention, there is also provided a linear spring device associated with the base and the member to be vibrated and the combination of electromagnet and armature has the effect of 'generating, in the organ to vibrate, vibrations close to

  the resonance of the linear spring device.

  In addition, according to the invention, the energy of the combination of electromagnet and armature, stored by the nonlinear spring device, comprises a kinetic energy

of the organ to vibrate.

  O will understand more fully the invention thanks

  to the detailed description below, considered in parallel

  to drawings in which: Figures LA, 1B and 1C are displacement curves as a function of time, illustrating the operation of

  the apparatus is constructed and operated according to a mode of

  DESCRIPTION OF THE INVENTION FIGS. 2A and 2B are representations of a vibrating system constructed and operating according to an embodiment of the invention; FIGS. 3A to 3E are representations of variants of a vibrating tray type system constructed

  and operating according to another embodiment of the invention.

  FIGS. 4 to 11 show examples of types of nonlinear spring constructions useful in vibrating systems constructed and operating according to the invention; Figures 12 and 13 show two vibratory plate type systems constructed and operating according to one embodiment of the invention and using a Kappa spring; Fig. 14 shows a Kappa spring useful in the invention: Figs. 15A and 15B are representations of a modified Kappa spring useful in the invention, and Fig. 16 shows a nonlinear spring structure useful in vibrating systems built and

operating according to the invention.

  Before going on to the detailed description of

  The invention will briefly explain the problem of shock in electromagnetic systems of the mobile armature type, with reference to Figures LA, 1B and 1C. Figure lA

  shows a displacement curve of an electronic system

  movable armature magnet in which the displacement amplitude A is equal to the maximum air gap G1. FIG. 1B shows a theoretical amplitude that could be achieved with the electromagnetic system of FIG. 1A, if there was not the physical limitation imposed by the shock of the armature against the electromagnet. FIG. 1C shows the amplitude of an electromagnetic system constructed and operating according to the invention, in which

  the amplitude of the electromagnetic system during the half

  cycle away from the frame is increased beyond the limits of the gap. Techniques to obtain the

  desired result will be described below.

  The invention will now be described with particular reference to the drawings. Note that, although most of the drawings relate to a particular type of vibrating system, the type of vibrating platters or vibrating screens, the invention is not limited to these types and is applicable

  to all appropriate electromagnetic vibrating systems.

  FIG. 2A shows a vibrating system whose general construction comprises a base 10. A mass to be vibrated 12 is mounted on the base 10, for example by leaf springs 11. An armature 14 is fixedly mounted on the mass 12 On the base 10 is also mounted an electromagnet 16 disposed opposite the armature 14 and defining with it an air gap 18. Two low damping coil springs 20 are mounted on the base opposite the mass 12, but are separate of it -7- at rest by a distance L. The distance L represents

  typically one third of the air gap at rest.

  A particular feature of the invention is that the springs 20 do not touch the mass 12, except when it approaches the electromagnet 16, that is to say when the gap 18 is minimal. Thus, it is understood that the springs 20 may be linear springs which, in this construction, constitute a nonlinear spring system because they are in action only

  during a part of the relative displacement of the organs.

  In the embodiment of FIG. 2A, the two springs 20 have the same length and touch the mass 12

approximately at the same time.

  Figure 2B shows a variant in which are provided, instead of two identical springs 20, springs 21 and 23 of different length. The spring 21 is longer than the spring 23 and touches the mass 12, along its travel path, more t8t than the spring 23. It is therefore understood that by using several springs acting on the vibrating system along different parts of the travel route, one can

  achieve a desired force / displacement characteristic.

  Instead, or in addition, combinations can be used

  springs with different characteristics.

  The operation of the apparatus shown in FIG. 2A will be better understood by considering the displacement curve of FIG. 1C which, as mentioned above, indicates that the amplitude is limited in one direction but not in the other. This limitation is ensured by the action of a non-linear spring system formed of the springs 20 of the embodiment of FIG. 2A. The non-linear spring system prevents the armature from striking the magnet and has the effect of storing the kinetic energy at high speed of the moving elements as well as the electromechanical energy of the magnet until the armature stops momentarily at its minimum air gap. Immediately thereafter, the armature is repelled by the electromagnet while the non-linear spring system releases the stored energy so that the armature is projected in force in the opposite direction with a large amplitude. The linear springs 11 return the armature to its zero position and the next cycle begins. It is understood that the force generated by the linear springs 11 increases rather slowly with the displacement, while the force generated by the springs 20, which is applied only after a displacement L starting from the zero position, during the contact between the springs 20

  and the mass 12, increases rapidly with the displacement.

  It is therefore obvious that the resulting force of the system comprising the springs 11 and 20 substantially corresponds to the force required to absorb the kinetic energy of the moving parts and the magnetic energy of the electromagnet and front armature combination. than

the air gap does not cancel.

  In the embodiment shown in Figures 2A and 2B, a nonlinear spring system is formed by the combination of two linear springs. It is also possible to use one or more non-linear springs, only

  or in combination with linear springs.

  A general condition is that throughout the system displacement cycle, the natural frequency of the vibrating system including the springs and masses generally corresponds to the desired frequency of the electromagnet. The existence of the system comprising the springs 20 is a main feature of the invention since these springs act to prevent "knocking" of the apparatus at large amplitudes and to store electromagnetic and kinetic energy as the gap is approaching zero and accelerating mass

  vibrating in the other direction at high speed.

  For the sake of clarity and to distinguish the invention from the prior art, the following terms will be used throughout the text msystem of nonlinear springs "and" nonlinear spring device "to designate a system or device of springs in which the stiffness c varies in the range of service range of the springs at any given time.This definition thus excludes the structure described in US Patent 2,187,717.

  constant in any given range of service amplitude.

  A main feature of the invention is that the spring system has only low internal damping or low friction, so that the spring system has the effect of converting substantially all of the magnetic energy it

  absorbs the kinetic energy of the mass to vibrate.

  Thus, the spring system does not need to act as a damper, which would be a waste of energy. In practice, it can be seen that to match the force required to decelerate the mass to zero speed without striking the magnet, the spring system

must be nonlinear

  It should be noted that for the sake of clarity, although the above discussion concerns a system in which an electromagnet is stationary and an armature is moving relative thereto, the invention is equally applicable to the inverse system in which frame is fixed and the electromagnet moves. In general, the invention as described above is applicable to the relative movement between the electromagnet and its armature, which includes the movement of the armature, the electromagnet or all

both.

  Reference will now be made to FIGS. 3A to 3E, which illustrate various constructions of an electromagnetic vibrating system of the type of vibrating tables. For clarity and conciseness, the elements common to all the various constructs will be described only with reference to FIG. 3A and the same references will be used.

  for the identical parts in all Figures 3A to 3E.

  The electromagnetic vibrating system of the type of vibrating tables that is shown comprises a vibrating base 22 mounted by means of weak springs 24 on a fixed support 26, such as the ground. A plate 28 which is to be vibrated along an axis 30 is mounted on the vibrating base 22 by means of leaf springs 32 and 34

  which generally satisfy equation (1).

  An electromagnet 36 is mounted on the vibrating base 22 and an armature 38 is mounted on the plate 28, in front of the electromagnet 36 from which it is separated by an air gap 39. A nonlinear spring system 40 indicated schematically, is associated with the vibrating base 22 and the plate 28 so as to virtually store the magnetic energy generated as the gap decreases to a minimum. Various embodiments of nonlinear spring systems 40 will be described in detail

  thereafter with reference to Figures 4 to 11.

  The embodiment represented by FIG. 3A is characterized by the fact that the magnet 36 and the armature 38 are arranged along an axis parallel to the axis of

movement 30 of the vibratory plate 28.

  On the other hand, the embodiment of FIG. 3B is characterized by the fact that the magnet and the armature are aligned horizontally and thus make an angle P with the axis 30. The advantage of this construction is that it is simple to manufacture and another important advantage is that the gap is kept relatively small. This can be understood by considering that for a maximum displacement of 2A of the plate 28, the maximum air gap between the magnet and the armature will be 2A cosp in the embodiment of FIG. 3B, against a maximum of 2A for the fashion

of Figure 3A.

  The embodiment of FIG. 3C is similar to

* - 2479034

  that of Figure 3B except that it comprises two electromagnets 42 and 44 disposed on either side of the armature 38 from which they are separated by respective gaps 46 and 48. An electronic control 50 is designed to direct the current to one or other of the electromagnets when using a soft iron frame0 Or again, when the armature is a permanent magnet, the electronic control successively changes the polarity

electromagnets.

  The embodiment of FIG. 3D is similar to that of FIG. 3A and illustrates an example of a virtually non-damping spring system, constructed

  and operating according to an embodiment of the invention.

  Here, a leaf spring 52 is mounted on the base 22. The spring 52 can be considered as being linear and

  having a very low internal friction.

  A shock member 54 is associated with the plate 28 and adapted to apply to the spring 52 only during the part of the movement cycle of the apparatus where the air gap 39 approaches its minimum. During this part of the cycle, the spring 52 absorbs practically all the magnetic and kinetic energy generated and converts it almost completely into the kinetic energy of the vibrating elements according to the invention. It will be especially noted that in this embodiment, a linear spring is used to form a non-linear discontinuous spring system. It will also be noted that the shock member 54 may be formed of an elastomer

  such as rubber in order to reduce the impact noise.

  The embodiment of FIG. 3E is in fact a combination of the embodiments of FIGS. 3D and 3C, in that it uses two magnets 42 and 44. In this embodiment, the analogy with FIG. The spring system of FIG. 3D is a substantially non-damping bilateral spring system 56, typically comprising low-friction inner rubber cushions associated with first and second shock members 58

and 60 mounted on the plate 28.

  It will be noted that the use of two magnets as in the embodiments of FIGS. 3C and 3E has the effect of effectively limiting the vibration amplitude of the armature to the total distance between the two magnets. However, this arrangement does not have the advantage that one of the magnets, far from the zero line, can be energized only to assist the other magnet for large amplitude operation without the need for additional reinforcement. In this way a very symmetrical oscillation can be obtained, which is particularly desirable for certain operations.

such as sieving.

  It will be understood, with reference to all the embodiments shown in FIGS. 3A to 3E, that the plate 28 can also be a sieve or any other desired element and that the springs used can also be of any other type, for example coil springs, elastomeric springs or leaf springs. All these various constructions are also examples of other types of

  vibrating systems in which the invention can be used.

  Reference will now be made to FIGS. 4 to 11 which illustrate various exemplary embodiments of spring systems useful in the invention. FIG. 4 shows a conventional leaf spring 60 associated with a curved support 62. When the plate 28 deflects in the direction of the arrow in solid lines 64, the leaf spring 60 bears against the curved support 62 so that its Free length decreases by a distance "s" as shown in Figure 6, so that the spring is effectively stiffened. A deflection of the plate 28 in the opposite direction does not cause this stiffening. This gives a spring system that is not

  linear acting as a linear spring in one direction.

  FIG. 5 shows a variant of the embodiment of FIG. 4, in which first and second curved supports 66 and 68, which are applicable, are provided.

- 13 -

  both to the leaf spring 60 during its deflection in the direction of the arrow in solid lines 64 and none of which applies to the leaf spring 60 when it deflects in

opposite.

  Figures 7 and 8 show a nonlinear coil spring 67, respectively in the compressed state and at rest. As seen in Figure 8, the spring 69 is variable pitch. Under compression, the lower pitch coils are initially compressed until they are contiguous, which reduces the active length of the spring, thus increasing the stiffness of the spring along a portion of the spring.

of its deviation cycle.

  Figure 9 shows a conical spring which is also variable pitch. Here, the larger and therefore more flexible turns are compressed initially and rest against a support 70 and there remain the smaller turns which

define a stiffer spring.

  Fig. 10 shows another embodiment of a non-linear spring system comprising an elastomeric cushion 72 made of rubber, polyurethane or any other suitable material. The cushion 72 is housed in a generally conical bowl 74. The elastomeric materials used in the cushion have the property of being elastic in one direction as long as they can expand in another perpendicular direction. When the cushion is not compressed it is placed freely inside the bowl 74. When a compressive force is applied to the cushion along an axis 76, the cushion is pushed against the inner walls of the bowl, which effectively stiffens the system

of spring.

  The spring system of Figure 10 has the advantage of being simple in construction and having a very large

  energy storage capacity for a relative volume

  small. Its disadvantage is that its stiffness depends on the temperature and the aging of the material

- 14 -

  elastomer. Figure 11 shows a non-linear spring system similar to the embodiment of Figure 4 and intended to crimp with a vibrating system with two magnets as shown for example in Figure 3C. The spring system uses first and second curved supports 78 and mounted on either side of a leaf spring 82 so as to reduce the effective length thereof.

  function of moving in one direction or the other.

  FIG. 12 shows an electromagnetic vibrating system of the type of vibrating plates in which the non-linear spring system without damping constitutes a Kappa spring. The structure of the Kappa springs is described in US Pat. No. 4,129,290. This particular Kappa spring has the structure indicated generally in FIG. 14, having a central blade 85 and two lateral blades 87 and 89 connected to the central blade 85 by elements of Binding 91 and 93. L1 indicates the free length of each of the side blades 87 and 89 and L2 is half of the free length of the central blade 85. B indicates the free length of the connecting member 91 or 93, those are typically identical, this length being measured as indicated. When L1 + L2 = 3B, we get

a linear spring.

  According to the invention, 3B is chosen larger than L1 + L2. This gives a Kappa spring whose stiffness increases with the displacement in compression and decreases

with the displacement in traction.

  Referring now to Figure 13 which shows a vibrator comprising a vibrating base 84 mounted on a bearing surface by means of weak springs 86 and supporting an electromagnet 88. A first vibrating mass 90 is supported by several springs Kappa no Linear springs 92 of the type described above, on the base 84. Several linear coil springs 94 are also mounted on the base 84 and move towards the mass 90 from which they are separated by a spacing 96 which is equal, at rest, to approximately one third of the gap 98 defined between the electromagnet 88 and a frame facing it and supported by the mass 90. Another vibrating mass 94 is mounted on the mass 90 by means of springs 100. The vibrator shown may have many possible uses, for example the clamping of cast concrete and is an example of various uses of modes of execution

of the invention.

  Note that the nonlinear spring device shown in Figures 4 to 6 and 11 is a preferred embodiment of nonlinear spring device used with the invention. These constructions can be characterized as comprising a curved support surface defining a circular section. The force / displacement characteristic of such systems provides a linear range that allows them to satisfy equation (1) and, at larger displacements, a nonlinear range that allows them to match

force / displacement required here.

  It will be understood that the introduction of a nonlinear spring having the characteristics indicated in FIG. 1C gives a system whose natural frequency is linked to the amplitude. This is not the case with linear springs. However, in practice, the impact of amplitude has no effect on performance because in most applications there is a constant change in mass which in any case provides a non-linear element whose result is a same incidence of amplitude on the

frequency.

  It may be desirable in some applications to provide an electronic trigger circuit for applying electrical pulses to the magnet so that the system operates automatically at resonance with maximum amplitude at a minimum current. The addition of an appropriate reaction circuit can make it possible to use

- 16 -

  this device to adjust the amplitude.

  Reference will now be made to FIGS. 15A and 15B which show a modified version of the Kappa spring of the

  Figure 14, respectively at rest and in the compressed state.

  For convenience, common references are used for the common elements also appearing in FIG. 14. The variant represented by FIGS. 15A and 15B comprises elastomer shock cushions 102 and 104.

  placed face to face on the connecting elements 91 and 93.

  These shock cushions provide an additional device for storing and converting energy that comes into action only at a predetermined compression level,

  at the initial contact of the cushions.

  If the springs of Figs. 15A and 15B were used to replace the springs 92 in the vibrating system of Fig. 13, for example, the elastomeric cushions would only provide storage of kinetic and magnetic energy during the motion cycle portion. o The air gap is minimal. In this way, they ensure

  desired non-linearity of the system.

  It is understood that instead of a pair of elastomeric cushions comne shown, one could use one for the shock against a rigid element. The cushions may be formed of rubber or any other suitable material. According to another variant, they can be replaced by other types of springs characterized by the fact that they make a compression contact only on

  part of the movement margin of the vibrating system.

  FIG. 16, which shows an embodiment of a nonlinear spring system comprising a linear coil spring 110 fixed at one end to a rubber cushion 112 and a second end to a support surface 114. FIG. a generally cylindrical rubber cushion 116 is placed inside the coil spring 110 and is positioned, in a selectable manner, on a support stud

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  adjustable 118 which is screwed into a locknut 120 to mount the cushion 116 in a selectable manner relative to the cushion 112. The rubber cushion 116 may be retained in place by means of a protruding protrusion 122 protruding outside the stud 118. It can be understood that the structure of Fig. 16 provides an adjustable nonlinear spring system. By properly adjusting the position of the stud 118, one can choose the portion of the movement margin of the cushion 112 on which the cushion 116 plays the role of energy absorber. Thus, the nonlinear spring system of Fig. 16 can be viewed as a mechanically programmable non-linear spring system. It is also understood that several elastomeric cushions, each mounted on an adjustably positionable support, may be used to provide a multi-stage adjustable non-linear spring system. Such a system is particularly useful in the apparatus of the invention. invention but is not limited to such applicae

tions.

  It will be understood by those skilled in the art that the invention is not limited to what is particularly shown and described above. _ 18-

Claims (23)

  An electromagnetic vibrating system characterized in that it comprises a combination of electromagnet 16 and armature 14 generating vibrations and comprising at least a first and a second element defining between them an air gap 18, a base 10 supporting the first element, a vibrating member 12 connected to the second element and a nonlinear spring device associated with the base 10 and the vibrating member 12 and comprising means for storing a significant energy of the combination of electromagnet and armature as it approaches its minimum air gap and convert it   in kinetic energy of the organ to be vibrated.   2. System according to claim 1, characterized in that the nonlinear spring device increases in stiffness as the amplitude of deflection increases.   3.- System according to one of claims 1 and 2,   characterized by the fact that the spring device   linear is in action in a nonlinear range.   4. System according to one of claims 1 to 3,   characterized by the fact that the organ to vibrate   comprises a vibrating tray 28 or a sieve.   5. System according to one of claims 1 to 4,   characterized by the fact that the spring device   Linear connects the base and the organ to vibrate.   6. System according to one of claims 1 to 4,   characterized by the fact that the non-linear spring device does not connect the base and the vibrating member to one another and that it only makes contact between   them when the combination approaches its minimum air gap.   7. System according to one of claims 1 to 6,   characterized in that the nonlinear spring device comprises a plurality of linear springs 21, 23 which are actuated successively as the amplitude of deviation increases. Z479034 - 19 -   8. System according to one of claims 1 to 7,   characterized by the fact that the spring device   linear comprises a nonlinear spring 60 69.   9. System according to one of claims 1 to 8,   characterized in that the nonlinear spring device comprises a spring device having a linear characteristic in the vicinity of its rest position and a non-linear characteristic to a deflection   large amplitude in at least one direction.   10. System according to one of the claims - to 9,   characterized by the fact that the nonlinear spring device has a non-linear characteristic at a deflection   large amplitude in one direction.   11. System according to one of claims 1 to 10,   characterized in that the non-linear spring device comprises a leaf spring 60 associated with a curved support surface 62 so as to cooperate therewith at a predetermined deflection amplitude in at least one direction.   12. System according to one of claims 1 to 11,   characterized by the fact that the non-linear spring device comprises a leaf spring 60 associated with a plurality of curved bearing surfaces 66, 68, 78, 80 so as to cooperate with the latter at a deflection amplitude   predetermined in at least one direction.   13.- System according to one of claims 1 to 12;   characterized in that the non-linear spring device comprises a leaf spring associated with at least one support surface curved so as to cooperate with the latter at a predetermined deflection amplitude in one sense.   14.- System according to one of claims 1 to 13,   characterized in that the combination comprises a single electromagnet 36 and a single armature 38,   15.- System according to one of claims 1 to 13,   characterized in that the combination comprises two - 20 -   electromagnets 42, 44 and a single armature 38.   16.- System according to one of claims 1 to 15,   characterized in that the combination is disposed along an axis 30 parallel to the vibration axis of the system (Figure 3A) o   17.- System according to one of claims 1 to 15,   characterized in that the combination is disposed along an axis at an angle to the vibration axis of the system (Figure 3B).   18.- System according to one of claims 1 to 17,   characterized by the fact that the spring device   linear comprises a nonlinear Kappa spring 92.   19.- System according to one of claims 1 to 18,   characterized by the fact that the spring device   linear comprises a pneumatic spring.   20.- System according to one of claims 1 to 19,   characterized by the fact that the spring device   linear comprises an elastomer spring.   21.- System according to claim 18, characterized in that the Kappa spring comprises an elastomer spring. 22.- System according to claim 1, characterized in that the nonlinear spring device acts to store virtually all the energy   magnetic and kinetic vibrating system.   23.- System according to claim 1, characterized in that it also comprises a linear spring device associated with the base and the member to vibrate, the combination of electromagnet and armature acting in a manner to ensure a vibration of the organ to vibrate   in the vicinity of the resonance of the spring device.