FR2477806A1 - CONTACTLESS SWITCH - Google Patents

Abstract

CONTACTLESS SWITCH INCLUDING A BISTABLE MAGNETIC ELEMENT 4 ASSOCIATED, BY MAGNETIC COUPLING, WITH AT LEAST ONE ELECTRIC WINDING 5, ONE OR MORE ORGANS 3 TO PRODUCE A CONTINUOUS MAGNETIC FIELD AT THE LEVEL OF THE BISTABLE MAGNETIC ELEMENT, AND A CONTROL KEY 1 PER THE ACTUATION OF WHICH THE MAGNETIC POLARITY OF AT LEAST ONE REGION OF THE BISTABLE MAGNETIC ELEMENT IS REVERSE. ONE OR MORE ORGANS ARE PROVIDED, IN A WAY KNOWN IN ITSELF, TO PRODUCE, IN WINDING 5, EXPLORATION PULSES CAPABLE OF CREATING A MAGNETIC FIELD SUFFICIENTLY INTENSE TO CANCEL THE MAGNETIC POLARITY INVERSION. THE INVENTION IS APPLICABLE TO KEYBOARDS FOR GENERATING ELECTRICAL SIGNALS.

Description

The present invention starts from a switch

  especially for keyboards and comprising a bistable magnetic element which is associated, by coupling

  magnetic circuit, at least one electrical winding,

  ganes to produce a continuous magnetic field at

  of the bistable magnetic element, and a touch of

  by the operation of which the magnetic field

  tinu at the level of the bistable magnetic element is varied for a short period of time in such a manner

  as a result, at least in one of the regions of the

  bistable magnetic resonance which are distinguished by

  magnetic forces (coercive forces), the

  the magnetic distance (magnetization direction) is reversed so that, as a result of this inversion of the polarity, the switch switches from its "open" to "closed" switching state or from its "closed to" switching state. A switch of this type is described in German Patent No. 2,514,131. In the known switch the push button secured to the key carries a magnet.

  permanent two-layer annular

  which contains in the two magnetic layers

  two pairs of poles of opposite polarities, the pale of opposite names of the layers being superimposed

  so that the two antiparallel magnetic fluxes,

  on the other in the vertical direction, traverse in a horizontal direction the hole of the magnetic ring serving as an air gap. At the boundary plane between the two antiparallel magnetic fluxes, which corresponds to the neutral zone, the resulting magnetic flux presents the

null value.

  Below the magnetic ring is a magnetoelectric pulse generator consisting of a bistable magnetic core in the form of a short section of wire which is surrounded by one or more electrical coils and extends parallel to the fluxes. magnetic

  in the hole of the magnetic ring.

  As bistable magnetic elements,

  so-called bistable magnetic switching cores,

2477 & 06

  -2- it is appropriate to use in particular wires of the type called

  Wiegand whose constitution and manufacture are de-

  written in German Published Patent Application No.

  2 143 326. Wiegand sons are, in their composition,

  homogeneous ferromagnetic wires (for example, an alloy of iron and nickel, preferably 48% of

  iron and 52% nickel, or an alloy of iron and co-

  balt, or an iron alloy with cobalt and nickel,

  or cobalt alloy with iron and vanadium), preferably

  52% cobalt, 38% iron, and 10% vanadium) which, due to a special mechanical and thermal treatment, have a soft magnetic core and a hard magnetic shell, i.e.

  has a higher coercive force than the core.

  Wiegand yarns typically have a length of 5 to 50 mm, preferably 20 to 30 mm. If a wire Wiegand, in which the magnetization sense of the magnetic core

  soft corresponds to the magnetization direction of the envelope

  gnetic, is placed in an external magnetic field

  whose direction corresponds to the direction of

  the axis of the wire but whose meaning is opposed to the meaning of

  Wiegand wire, then the sense of magnetization of the soft core of the Wiegand wire is reversed in case of

  exceeding a field strength of about 16 A / cm.

  This inversion is also called resetting. In case of a new reversal of the direction of the field

  external magnetic sense of magnetization of the nucleus

  again as soon as the intensity of the external magnetic field exceeds a critical value, so that the

  core and envelope are again magnetized by

  rallèlement. This inversion of the sense of magnetization is

  very quickly and is accompanied by a strong vari-

  corresponding magnetic flux per unit of time (Wiegand effect). This variation of the magnetic flux can induce in an induction coil a pulse of

  short and very strong voltage (Wiegand pulse)

  depending on the number of turns and the load resistance of the induction coil reaching up to

about 12 volts).

  -3- When returning the kernel to its initial state a

  impulse is also produced in a coil of in-

  duction but this pulse has, compared to the case of the passage of the sense of magnetization antiparallel to that parallel, a significantly lower amplitude

and of opposite sign.

  If one chooses as external magnetic field

  an alternating field, capable of reversing the magnetism first

  tation of the core and then that of the envelope and bring them each in the state of magnetic saturation, then there, as a result of the change of the magnetization direction of the soft magnetic core, pulses

  Wiegand alternately presenting a positive polarity

  ve and a negative polarity and we can then speak of a symmetrical excitation of the wire Wiegand. For this, field strengths of about - (80 to 120 A / cm) to + (80 to 120 A / cm) are required. Inversion of magnetization

  of the envelope also occurs abruptly and

  also induces a pulse in the induction coil, but this pulse is much weaker than that induced during the inversion of the magnetization of the nucleus

  and is not exploited in most cases.

  If, on the other hand, we choose a magnetic field

  a field capable of reversing only the magnetization direction of the soft core and not that of the hard shell, then the strong Wiegand pulses occur only with the same polarity and

  then talk about an asymmetrical excitation of the wire Wiegand.

  This requires a field strength of at least 16 A / cm in one direction (to bring the Wiegand wire back to the initial state) and in the opposite direction a field strength.

from about 80 to 120 A / cm.

  It is characteristic of the Wiegand effect that the pulses produced by this effect are, as for

  their amplitude and width, to a large extent inde-

  pendent of the speed of variation of the magnetic field.

  than outside and have a high signal-to-noise ratio

  Vee. In the context of the invention can also be used bistable magnetic elements designed differently, provided that they comprise two

  magnetically coupled regions and present

  in relation to each other, a different magnetic hardness (coercive force) and

  similar to Wiegand threads, serve for the generation of im-

  rapid inversion pulses induced by the magnetization of the soft magnetic region. Thus it is described for example in German Patent No. 2,514,131 a core

  bistable magnetic switch presented in the form of

  me of a thread that is made of a hard magnetic core

  nickel-cobalt), an intermediate layer

  electrically conductive area (for example, in

  vre) deposited on the core and a soft magnetic layer (eg nickel-iron) deposited on the intermediate layer. Another variant further comprises a

  core formed of an inner conductor devoid of

  mance (for example in beryllium-copper) on which is then deposited the hard magnetic layer on which is then deposited the intermediate layer which is finally covered with the soft magnetic layer. This known bistable magnetic switching core, however, generates lower switching pulses than those

generated by a Wiegand thread.

  If in the case of the switch described in

  German patent 2,514,131 we press the key of com-

  Mande, then the magnetic ring engages the bistable magnetic element arranged parallel to it, so that the bistable element is first subjected to the magnetic flux produced in one direction, then passes through the neutral zone and is then subject to the magnetic flux produced in the other direction, that is to say the direction antiparallel to the first. During the return movement of the key

  the process proceeds in reverse order.

  is. The depression and the return movement of the

  control are effected by means of a click mechanism. The rapid inversion of the magnetic flux, thus produced at the level of the bistable element, causes, after each passage of the bistable element by the neutral zone

  of the magnetic ring, a reversal of the sense of magnetism

  of the soft magnetic region of the bis-

  table. The rapid change of magnetic flux is

  and thus in the electric coil mounted on the

  bistable induces in it a short and strong voltage pulse which is usable for switching purposes.

  This known switch has the disadvantage of

  fugitive switching signals, that is, after the return movement of the switch the previously produced switching signal can no longer be read

  by exploration, unless the switch is

  a special signal retention circuit which

  holds the switching signal until it is again suppressed when a condition is set in advance (eg the flow of a certain time

  or a specific event that occurs) is fulfilled.

  It is the same for switches which operate with contact or non-contact contacts by the action of a moving permanent magnet on a semiconductor sensitive to magnets (Hall effect) such switches are used in keyboards

  computer input. These keyboards have

  usually a matrix of conductive pathways

  intersecting points at each of the crossing points of which a keyboard switch is mounted. In the closed state a switch connects a line to a column of

the matrix of conductive paths.

  The states of the switch are recognized by explo-

  ration by sending an impulse to a conductive path

  trice and checking the presence of this impulse

  at the outputs of all conductive paths that cross

  feel said conductive path. This process is repeated cyclically for all columns or rows of the matrix, columns and rows being interchangeable

from the point of view of their function.

  -6- In order for a keyboard to function properly, it must be ensured that the scanning cycles are short enough so that during the hold time, after the operation of a switch, an exploration pulse passes suddenly. sr by the switch and can signal the "closed switch" status. Else

  On the other hand, it is necessary to avoid by appropriate measures

  required, for example as regards mounting, that a

  depressed map is explored several times

  the hold time so as to signal each time the "closed switch" state. In the case of the control keys which are described in the German patent

  No. 2 514 131 the holding time, during which the

  mutator is closed, is determined by the length of time

  during which a user holds the key

  dark. The impulses produced in the bistatic element

  ble are in fact brought to a signal amplifier

  which, at the onset of the first impulse

  in the bistable element by depressing the key, delivers a constant DC voltage signal

  which is again removed as soon as the

  Reverse polarity pulse produced by the return movement of the key. The state "closed switch" can only be explored as long as the signal

  DC voltage is present at the output of the amplifier.

  signal indicator and the scanning frequency must be adapted to the maximum typing speed that is

  can wait on the part of the user.

  Now, the object of the present invention is to create a contactless switch suitable for keyboards and

  producing, without the need for co'9-

  in the field of assembly, non-fugitive switching signals which are triggered by the actuation of the control key and are maintained until

  that they be canceled by an exploration process.

  This object is achieved, for a switch of the type described above, by the fact that, in order to recognize the state of the switch, it is provided, in a manner known per se, one or more members intended to produce pulses of electric exploration that are connected

  electrically to winding, and that the amplification

  of and the width of the scanning pulses, the number of turns of the winding and the force of the magnetic coupling of the winding are adapted in such a way that

  to each other that the intensity of the magnetic field pro-

  at the level of the bistable magnetic element, by the scanning pulse in the winding, is sufficient to cancel the change in the magnetic polarity of the bistable magnetic element.

  the operation of the switch control button

  tor. Other advantageous features of the invention

are described later.

  The continuous magnetic field can in principle be created in any way, a permanent magnet

  however, it is preferably used for this purpose.

  So that the continuous magnetic field can

  pour the magnetization of the bistable magnetic element

  the continuous magnetic field must have a component

  is notable in the direction of the bistable magnetic element; advantageously, the lines of the continuous field extend, at the level of the bistable magnetic element, as much as possible parallel to the magnetic element

bistable.

  It is therefore sufficient to use only one

  permanent bipolar mantle. Instead of a permanent magnet, however, it is also possible to use, to influence the bistable magnetic element, an electromagnet which

  surrounds, for example in the form of a winding

  along, the bistable magnetic element and the winding

  by which the scanning pulses are sent.

  The electromagnet is energized only when the switch is actuated. An electromagnet is particularly suited to serve as a means of producing the continuous magnetic field if the control keys used are not

  not mechanically operated keys but

  touch-sensitive devices that react electronically

only when a finger approaches it.

  In the case of a mechanical control key it is fixed to the push of the key advantageously a permanent magnet which approaches the magnetic bistable element in case of actuation of the control key

  and thus increases the intensity of the magnetic field at

  calf of the bistable magnetic element.

  In principle, however, it is also possible to

  that the permanent magnet is fixed and that the magnetic element

  bistable tick is approached to the permanent magnet by pressing the key. However, it is also possible to influence the intensity of the field of permanent magnets, at the level of the bistable magnetic element,

  by means of a ferromagnetic plate or an element

  logue. The field of a single magnetized bar, at the level of the bistable magnetic element, can for example be

  made more intense by introducing the bar between

  meant and the magnetic element bistable a bar ferro-

  magnetic so as to focus the magnetic field. However, the magnetic element can also be arranged

  bistable between two magnetic bars of polarities op-

  placed parallel to each other and the bistable magnetic element, and shortcircuiter these bars more or less by approximation and removal of a bar or block

  ferromagnetic. The movement of the ferromagnetic part

  that, for example unfe t8le, is achieved by means of the movable control key to which or to the switching pusher of which this sheet is, in the case of

simpler, fixed rigidly.

  A Wiegand wire is particularly suitable for

  vir of bistable magnetic element because of its way

  characteristic of producing signals magnetically

  tick. In order to obtain signals with a good efficiency it is furthermore advantageous if the windings in which signals are transmitted or produced are associated, by a magnetic coupling as tight as possible, to the bistable magnetic element, that is to say -say

  that they are placed closely around the

  bistable gnetic. The windings can however, in principle, also be arranged next to the element

  bistable magnetic field as long as a magnetic coupling

  that enough is kept between them.

  The characteristic impulse produced by the

  version of the magnetization of the bistatic magnetic element

  ble as a result of the first scanning pulse after the switch is actuated, can, in principle and advantageously, be generated in the same winding as that in which the scanning pulse creates the

  magnetic field that leads to this inversion of the

  mantation of the bistable magnetic element. Due

  the characteristic and abrupt reversal of magnetism

  in at least one of the different regions of the

  bistable magnetic resonance the voltage pulse induced in the winding by this inversion is, especially when using a Wiegand wire as an element

  bistable magnetic, significantly stronger than the impulse

  exploration and can be easily distinguished from it. However, it is also possible to use two separate windings, preferably with

  turns, one of the windings used to

  see the exploration pulse and the other to detect

  the eventual change in the polity

  the magnetic element of the bistable magnetic element

detector bearing).

  In principle, the switch according to the invention

  can work equally well under conditions of exci-

  only under asymmetric excitation conditions of the bistable magnetic element. In the case of symmetrical excitation, the magnetic polarity of the hard magnetic region of the bistable magnetic element is reversed when the switch control key is actuated only as a result of the first

  exploration pulse occurring after the action-

  the control key. Therefore, the "switching" of the bistable magnetic element requires higher magnetic field intensities than

  case of asymmetric excitation of the magnetically

  table, which leaves the sense of magnetization of the region

  hard magnetism of the bistable magnetic element

  ge and only reverses the polarity of the soft magnetic region of the bistable magnetic element. In addition, in the case of symmetrical excitation of the bistable magnetic element, a pulse of an amplitude is produced when the control key is actuated.

  the first exploration impulse produced after the

  switching, but of reverse polarity.

  The pulse already produced when the control key is actuated may, if necessary, for example to protect the mounted electronic equipment

  downstream, or desirable, for other reasons, to be sup-

  awarded by provisions on the plan of assembly, by

  example by means of a discriminator circuit.

  That's why it's definitely more advantageous,

  in the case of the switch according to the invention,

  the asymmetrical excitation of the magnetic element

  bistable, that is to say, to take care, by a dimension-

  appropriate arrangement and arrangement of the members creating the continuous magnetic field or appropriate winding sizing and arrangement and a suitable choice of the amplitude and width of the scanning pulses, in the case of a magnetization Initially antiparallel to the soft magnetic region of the bistable magnetic element, relative to the hard magnetic region, the magnetization inversion field at the bistable magnetic element has an orientation and intensity such that the direction of magnetization of the soft magnetic region of the bistable magnetic element can certainly be reversed so as to become parallel to the magnetization direction of the hard magnetic region may; that the sense of magnetization of the latter can not

to be reversed.

  It is also possible to operate the comnnta-

  in such a way that, when the switch is actuated, the direction of magnetization of the soft magnetic region of the bistable magnetic element is reversed so that its direction of magnetization then corresponds to that of the hard magnetic region and that consequently of the scanning pulse, which then occurs and creates a magnetic field in the associated winding by coupling to the bistable magnetic element, the polarity of the soft magnetic region of the bistable magnetic element is

  inverted by magnetic means so that the senses of

  magnetic regions hard and soft become

  are antj.paralleles. As, however, in the case of polarity reversal causing the magnetization of the region

  magnetic drive of orientation parallel to that of

  In this case, a significantly lower pulse is produced than in the case of a polarity reversal passing the antiparallel orientation to the parallel one, the switch according to the invention is advantageously used so that, after the actuation of the switch, the magnetizations of the Magnetic-hard and soft regions are antiparallel and that soft magnetic region

  as a result of the appearance of the impulse of ex-

  following explanation, a reversal of polarity

  the sense of parallel magnetization. In this case, it is produced in the winding detector a pulse

  weak when actuating (putting into action) the

  mutator but a strong pulse when exploring the actuated switch (put into action). The pulse already produced when the control key is actuated may, if necessary, for example to protect the downstream electronic equipment, or desirable, for other reasons, be removed by provisions on the plan of the assembly, for example

means of a discriminator circuit.

  The switch according to the invention offers any

  a series of advantages. The information resulting from the

  The operation of the control key is maintained, without the need for energy input, for example from a source of electric power, until it is collected by exploration. Even after a power failure the information is still present. It is suppressed in the case and at the precise moment when it is collected by exploration, that is to say that it is available the necessary time but that after the exploration the switch is immediately ready to be activated at new. The scanning frequency does not need to be chosen based on the switch-on time

  of the switch but only according to the rate of

maximum training to plan.

  Compared to mechanical contact switches

  In addition, the switch according to the invention has the advantages that there is no contact wear and that no contact bouncing occurs.

  that we can dispense with bouncing filters.

  Compared to switches using the effect

  Hall, the switch according to the invention has the advantage

  addition that switching the switch requires no power supply and that

  Expenditure on assembly is reduced.

  Two exemplary embodiments of the invention are explained below with the aid of the accompanying drawings, which are very simplified, in which: FIG. 1 represents, in principle, the

  construction of a switch according to the invention

  taking a Wiegand-wire as a magnetic element

bistable;

  FIG. 2 shows the hysteresis cycle of a Wiegand wire in the case of asymmetric excitation; Figure 3 shows the arrangement of such a switch in a keyboard; and FIG. 4 shows the arrangement of a modified embodiment of the switch, having separate windings for the scanning pulses.

* and the transmission of Wiegand impulses in a

  vier. Figure 1 shows schematically and in its

  principle the construction of a switch according to the

- - 2477806

  vention. A control key 1 has at the lower end of its switching pusher 2 a permanent magnet rod 3. Alongside the magnet

  permanent 3 and next to it in a longitudinal direction

  dale is fixedly mounted a wire Wiegand 4 which carries an electric wire wrap 5. The control key 1 can be pushed down according to the arrow 6 and

  thus be operated. The return movement of the

  control cheer 1 is carried out mechanically by a coil spring 7 mounted between the head of the control key 1 and a fixed stop S. After its return movement, the control key 1 bears with a shoulder 2 ',

  provided at the bottom of its switching pusher

  2, against the underside of the stop 8.

  When the switch is not pressed, the

  mant 3 occupies its upper terminal position

  felt in solid lines. In case of activation of the

  mutator magnet 3 is brought for a short time in the position shown in phantom

  in Figure 1, so that the magnetic field

  that emanating from the permanent magnet 3 becomes more intense

  Wiegand wire 4. As a result, the magnet nucleus

  Wiegand's soft tick is made to adapt its sense of magnetization to the magnetic field superimposed on it and, as far as it has not yet taken place, to change the direction of magnetisation, and in this respect the thread

  Wiegand 4 must be arranged in such a way that the senses of

  of its soft magnetic core and its enve-

  hard magnetic loppe are then opposed.

  In the hysteresis cycle represented at

  FIG. 2 for the preferred case of asymmetric excitation of Wiegand wire 4 (B = magnetic flux, H = Intensity).

  magnetic field tee) this corresponds to the passage, on the upper curve, of the saturation interval 11 (in the field of positive remanence) to the saturation interval 12 (in the negative remanence domain); during this process there is a sudden change in the magnetization state of the soft magnetic core

- 14 -

  of wire Wiegand 4 (indicated in FIG. 2 by the dotted portion 13 of the hysteresis cycle), which change

  leads to a weak Wiegand impulse that is not

  times not exploited but removed.

  The switch is periodically explored by

  electrical exploration impulses that are

  in the winding 5 at terminal 9. The

  The amplitude and the width of the scanning pulses are such that the magnetic field created during a short period of time in the winding 5 is sufficient to reverse, by magnetic means, the polarity of the magnetic core.

  Wiegand 4 and bring it back to the

  positive saturation valle 11 o the envelope and the core of the wire Wiegand are magnetized parallel. During this reversal of the magnetization, the values B and H follow the lower part of the hysteresis cycle of FIG. 2 and during this process a sudden change in the magnetization of the core of the wire occurs in zone 14. Wiegand 4, which change induces in the winding 5 a strong voltage pulse

  (Wiegand pulse) which is received in a detection circuit

  mounted downstream of the terminal 9 of the winding 5 and

  is recognized as a signal "switch action-

  If the "Wiegand" wire is already in the positive saturation interval 11, then when a scanning pulse occurs,

  the exploration pulse can not trigger any

  impulse Wiegand and the lack of impulse Wiegand re-

  presents the information "switch not actuated" or

"open switch".

  It is obvious that the act of

  order 1 several times between two im -

  successive exploration drives does not change the content of the information. The polarity reversal of the

  wire Wiegand 4, caused by an actuation of the

  order 1, is maintained until

  it is recognized and at the same time canceled by a

exploration drive.

247780-6

- 15 -

  Figure 3 shows the preferred way of using

  the switch in a keyboard part of which is

  presented schematically. The keyboard includes a matrix

  this of intersecting conductive paths which are arranged according to their function so as to form lines Z1, Z2, Z3, Z4, etc. and columns Si, S2, S3, S4, etc. At each crossing point there is a switch 15 which connects a line and a column therebetween. The closed state of a switch can

  be detected by passing through the lines "or colon-

  "periodically signals of exploration and

  the appearance of a response signal and the co-

  lonnes (or lines) in which this signal appears.

  In this case the switches are made in accordance with the invention, which is indicated at a location in Figure 3 symbolically by the fact

  that the column Si and the line Z3 are connected by the

  5. In case of actuation of the

  15 'it occurs when feeding the

  Si column with an exploration pulse, in the

  rolling 5 a Wiegand impulse that can be recon-

  in a detector circuit connected to line Z3.

  If two separate windings are used, namely a winding Sa for the scanning pulse and a winding detector 5b for the Wiegand pulse, then the switch is constructed as shown

  schematically in Figure 4, whose mode of representation

  is similar to that of Figure 3. In this case, unlike that of Figure 3, the column Si

  and line Z3 are not connected by electrical conduction

  but only coupled together by means of

gnétique.

0 0 0 0

O 0 0-o -16

Claims (10)

  1. - Contactless switch, especially   for keyboards intended to produce electrical signals   which comprises a bistable magnetic element which is associated by magnetic coupling with at least one electric winding, members for producing a continuous magnetic field at the bistable magnetic element, and a control key by actuation. of which the continuous magnetic field at the bistable magnetic element is varied for a short period of time in such a way that, in fact, at least in one of the regions of the bistable magnetic element which are distinguished by magnetic hardnesses (coercive forces) different, the magnetic polarity (magnetization direction) is reversed so that as a result of this inversion of the polarity the switch   switch from "open" to "open"   the "closed" switching state to that "or-   green ", characterized in that, to recognize the state of the switch, it is provided, in a manner known per se,   one or more organs intended to produce im-   electric exploration pulses that are electrically connected to. winding (5), and in that the amplitude and the width of the scanning pulses, the number of turns of the winding (5) and the magnetic coupling force of the winding (5) are adapted to to each other in such a way that the intensity of the magnetic field created at the level of the magnetic element   bistable (4), by the exploration pulse in the   turnover (5), is sufficient to cancel the change   come into the magnetic polarity of the bistable magnetic element (4) as a result of pressing the key control (1) of the switch.   2. - Switch according to claim 1,   characterized in that the organ or organs (3)   born to produce the continuous magnetic field is (are)   a permanent magnet or a set of permanent magnets. - 17 - 278   3. - Switch according to claim 1 or 2, characterized in that the organ or members (3)   intended to produce the continuous magnetic field and the   bistable magnetic element (4) are mounted in such a way that the continuous magnetic field at the bistable magnetic element (4) is, at least when the switch is actuated, as far as possible parallel to the longitudinal direction of the element magnetic bistable (4).   4. - switch according to claim 2, characterized in that the permanent magnet (3) is fixed at the end of the push button (2) of a key mobile control unit (1).   5. - switch according to claim 2, characterized in that the permanent magnet or the permanent magnets and the bistable magnetic element are each mounted fixed and in that the movable control key   is mechanically connected to a movable ferromagnetic element   the, for example a sheet, which serves as coupling member   magnet between the permanent magnet or the magnets   magnets and the magnetic bistable element and is, in case of actuation of the switch, brought to a position where it reinforces the continuous magnetic field at   level of the bistable magnetic element.   6. - Switch according to any one of   Claims 1 to 5, characterized in that the element   magnetic bistable (4) is a Wiegand wire.   7. - Switch according to any one of   Claims 1 to 6, characterized in that the windings   elements (5; Sa, Sb) are placed around the element magnetic bistable (4).   8. - Switch according to any one of   Claims 1 to 7, characterized in that the element   magnetic bistable (4) is associated by coupling a single winding (5).   9. - Switch according to any one of   Claims 1 to 8, characterized in that provision is made   an asymmetric excitation of the magnetic element bis- - 18 - table (4).   10. Switch according to claim 9, characterized in that the winding or the windings (5), the bistable magnetic element (4) and the organ or S the members (3) intended to produce the magnetic field.   continuously arranged in such a way   port to others that after a switch actuation the magnetization direction of the soft magnetic region and   that of the hard magnetic region of the magnetic element   bistable (4) are concordant whereas after the   snapping of an exploration pulse they are anti-   parallel (opposed to each other). O O O O O-O-O-O