DE1640292A1 - Rear derailleur - Google Patents

Description

Patent attorneys <\ Ω ι Π Ο Q *}

Dipl. Ing. C. Wallach ' ^{p 4 ψ L} * * ■

Dipl. Ing. G. Koch
Dr. T. Haibach

8 Munich 2

Kaufingerstr. 8, Tel. 240275

Dr. Expl.

Hawker Siddeley Dynamics Limited, Hasfield

England

"Rear derailleur"

The invention relates to improved switching means and switching devices consisting of these.

The switching device according to the invention has a number of reed switches arranged at an angle about an axis, each of which is put into a first or second state by means of a magnetic field, as well as means which are assigned to each of the switches so that the switch in question actuates accordingly has been maintained in its second state

109811/0334 BAD

can be and an electromagnet with an armature, which is rotatably arranged around said axis next to the switches and is excitable in order to change the switching state of any neighboring reed switch.

According to a particular embodiment of the invention, the switching device has a number at an angle around an axis arranged and radially extending from this reed switch, each of which is actuated by a magnetic field and an open or Can assume the closed position, each Sehalter is assigned a permanent magnet, which him in the closed position, in which it has been brought, while an electromagnet with a fixed coil and one around said axis holds rotatable armature in the vicinity of the switch to change the position of an adjacent reed switch can be excited.

The invention also relates to a switching device W according to one of the two embodiments described above in combination with means to apply excitation pulses to the electromagnet in synchronism with the rotation of the armature in order to change the position of the switch.

The term "reed switch" is used here to mean a switch to be referred to, which has at least two electrical contacts which are arranged within a shell and mediate

- 3 109811/0334

BATH ORIGINAL

an applied magnetic field between a first and a second state "can be actuated. The envelope can be evacuated or contain a gas that is inert with regard to the material of the contacts, such as nitrogen gas.

According to a feature of the invention, an electrical selector is provided which has a first electrical pulse generator for selectively closing any of at least two of the reed switches of a primary switching device according to the present invention Invention has to thus provide an electrical connection with one of at least two secondary inventive Switching devices to choose, as well as a second electrical pulse generator, which by the selected electrical Connection for selectively closing any of at least two of the reed switches of the secondary switching device and thus can be actuated to make the desired electrical connection.

In a particular embodiment according to this invention Feature is an electrical selector is provided, which has a primary switching device according to the invention, the can be actuated by an electromagnet, with at least two of their reed switch with the electromagnet in question a corresponding number of secondary switching devices according to the present invention are connected and

- 4 109811/0334

the armature of all switching devices a synchronous rotation run at an angle, and with a first pulse generator on the electromagnet of the primary switching device at a first angular position of the armature for closing one of the reed switches of the primary switching device and thus for Selecting an electrical connection with the electromagnet of the one of the secondary switching devices in question acts, while a second electrical pulse generator through the selected electrical connection on the electromagnet of the selected secondary switching device at a second angular position of the armature to close one of the reed switches the selected secondary switching device and thus acts to maintain the desired electrical connection.

The electrical selector according to the previous two paragraphs can neutralize such as at least one Have constant current generator, which generates an electric current through the electromagnet of the primary switching device and / or by the electromagnets of the secondary switching devices can send in a direction opposite to the first or second pulse generator to at least one again to bring the reed switch of the corresponding switching device into its open position.

According to a second inventive feature is an exceptional

• 109811/0334

BATH ORIGINAL

setting variable resistor is provided, which is formed from a switching device according to the invention and from a switching device according to the invention and an arrangement of at least two fixed value resistors, each of which is connected at its terminal to a corresponding reed switch of the switching device.

In a particular embodiment according to the second according to the invention Feature has an intermittently variable resistance a switching device according to the invention and at least zv / ei arrangements of fixed-value resistors, each arrangement the pest value resistors has a number of such resistors in a graded order of resistances are arranged, each of which is uniquely connected to a corresponding reed switch of the switching device, wherein each of the fixed-value resistors in each row is connected to its terminal with a first common point in this row while its other terminal is connected to one terminal of the corresponding reed switch, with the other Terminals of the terminals assigned to each row of fixed-value resistors are connected to a second common point in this row are and the first or the second common point of this series with the first or the second common point Point of the next row is connected that the actuation of the switching device enables any

109811/0334

Fixed value resistor of a series with any best value resistor the next row is connected in series.

The invention also relates to a digital-to-analog converter with pulse generators for actuating the switching device of an intermittently variable resistor according to the invention according to one of the immediately preceding paragraphs with at least one angular position of your anchor and according to a pre- " selected information in digital form, with the fixed-value resistors are chosen such that their effective resistance represents the preselected information analog in digital form.

The invention further relates to a generator a staircase-like waveform having an intermittently variable resistor according to the invention, and means for temporarily closing each of the reed switches of the switching device in an appropriate sequence, and means for feeding egg ψ nes electric current flowing through the intermittent variable resistor , the voltage difference produced in the intermittently variable resistance having the desired shape.

Some exemplary embodiments according to the invention are shown below described in connection with the accompanying drawings; show in it:

109811/0334

BATH ORIGINAL

Fig. 1 is a partial sectional view of a device according to the invention Switchgear;

Fig. 2 is a sectional view along the line H-II in Fig. 1, with some components missing;

3 shows a circuit diagram of an electrical device according to the invention Voter; and

Fig. 4 is a circuit diagram of an intermittent according to the invention variable resistance.

The switching device according to FIGS. 1 and 2 has a number Reed switch 1 on - e.g. thirty-two switches - which are arranged around an axis 2 at equal angles and are located extend radially from the axis. Each switch 1 is an ON ATJS switch with two normally open contacts 3 and 4 within a sheath 5, the contacts being brought into the closed position by an applied magnetic field will. The switches are supported on a ring-shaped board 6, which is conveniently also a number printed Circuit elements carries.

Separate means are assigned to each switch 1 to keep it in the closed state in which the switch

109811/0334

has been displaced by the application of a magnetic field. These means can for example consist of a permanent magnet 7, the is held in a corresponding slot in the panel 6.

In a modified embodiment according to the invention (not shown), each switch 1 represents a changeover switch with two side contacts and a changeover contact, with the changeover contact in a first position of the switch 1 "touches one of the side contacts while the changeover contact switches over when a magnetic field is applied, and so the other Touches the side contact, the switch 1 being held in this second position by the permanent magnet 7.

A shaft 8 is arranged concentric to the axis 2 and rotatable about this axis and rotates together with the armature of one Electromagnet, the coil 9 of which is inside the central opening the table 6 is arranged stationary.

The armature has two radially extending arms 10 and 11, which are each arranged on each side of the panel 6 and each have a pole face 12 and 13, which are arranged in relation to the switch 1 in such a way that the one between the arms 10 or 11 located switch 1 is closed or reopened when the coil 9 is errs according to the desired -kge for this switch by an electrical impulse! _w i _r d _#

- 9 -109811/0334

; · ORIGINAL BATHROOM

The armature's magnetic circuit is provided with a sleeve 14 which forms one end of the arm 11 and is arranged coaxially around the shaft 8 and extends through the coil 9 to the Ann 10 extends.

In the working state of the device, the shaft 8 rotates with the arms 10 and 11 and the sleeve 14. At the given moment, when a given switch 1 is to be operated and is located between arms 10 and 11, an electrical pulse becomes more appropriate Polarity is applied to the coil 9 in order to create a resulting magnetic field between the pole surfaces 12 and 13 to generate that is sufficient to close the contacts 3 and 4 of this switch 1. After the electrical pulse ends the magnet 7 associated with this switch 1 holds this switch in the closed position.

Similarly, one of the switches 1 can switch from the closed Position can be brought into the open position by energizing the coil 9 with a pulse of opposite polarity, when the switch in question is between the arms 10 and 11, the magnetic field thus generated to overcome the Effect of the associated magnet 7 is sufficiently strong.

Two or more switching devices © ** can naoh Wtmsoh along a shaft 8 common to all devices in axial

- 10 -

103 * 11/0334

spaced apart so that the armature of the devices can be rotated synchronously. Magnetic screens 15 can be used between adjacent switching devices for localization of the magnetic fields E'a associated with each device.

LIe switches 1 do not have to be radially from the axis 2 - as described - extend, but can also run parallel to this axis. The switches 1 one or more Switching devices can be attached to the wall of a cylinder coaxial with axis 2.

It can be seen that the switching device described can be actuated by applying electrical excitation pulses the coil 9 in synchronism with the rotation of the shaft 2 for actuation the switch 1 can be applied in a preselected order or according to a predetermined form.

The electrical selector shown in FIG. 3 has a number of switching devices according to the invention, which are connected to a (not shown) the shaft 8 similar shaft are arranged at a distance from each other, the (not shown) armature of all Holding devices can be rotated in synchronism and in the same phase are.

ι ο 9 an / υ j 3 1.

- 11 SAD ORIGINAL

A first - namely the primary - series of switching devices is "shown at 21, with its solenoid is designated by 22. In the switching device 21 is depending one contact of one of their thirty-two reed switches connected to a common point 23, with the other contacts the reed switch shown at 24; therefore the operation of the switching device is similar to the operation of a single pole thirty-two-way rotary switch, the switching device 21 in Pig. 3 is shown symbolically as such. The series of switching devices further includes thirty-two secondary switching devices 25 in which the Reed switch contacts are connected similarly to the switching device 21, so that they are each referred to similarly.

Each of the non-common contacts 24- of the primary switching device is connected to one terminal of the electromagnetic coil 26 of a corresponding secondary switching arrangement 25, each of these electromagnetic coil terminals being connected in a similar manner via a corresponding rectifier 27 of the indicated polarity to one terminal of a constant current generator 28, the other of which Terminal with a "NuIl" -Klemne 29 is connected. All other terminals of the electromagnetic coils 26 are connected to a common "line" terminal 30 ■ and also via a rectifier 49 of the specified polarity to earth.

- 12 -

109811/0334

The electrical selector also has an additional switching device 31 on. This device has a shape generally that of the switching device according to the invention is similar, but differs from it in that the permanent magnet 7 associated with the reed switches is omitted. The electromagnet coil 9 is also replaced by a permanent magnet. The anchor of the additional Switching device rotates in synchronism in the working state

"and in the same phase with the anchors of the series of switching devices, all of the armatures being arranged on the above-mentioned common shaft; it can be seen that in in this case each of the reed switches of the additional switching device in a certain order and during that Periods of time is temporarily brought into the closed state in which the pole faces of the armature of this device drag along the reed switch in question. Each of the thirty-two reed switches of the additional

) Switching device is through one contact with a common Point 32 connected; the remaining contacts of the reed switches are shown at 33, being thirty-two "Choice" terminals 34 are connected accordingly. The common one Point 32 is connected to the input of a DC amplifier 35 whose output is connected to a common point 37 via a rectifier 36 of the specified polarity is, which in turn on the one hand with the common point 23

- 13 109811/0334

ÖAD ORIGINAL

and on the other hand via a rectifier 38 of the specified Polarity is connected to a common point 39. Of the common point 39 is connected to one terminal of a constant current generator 40, the other terminal of which is connected to earth and via the solenoid 22 also with a "dam" clamp 41 is connected.

In the case where each of the secondary switching devices 25 has thirty-two reed switches, there is one contact each reed switch is connected to a common point 42. The remaining contacts 43 can be connected to any electrical circuit or to electrical circuits individually with which the desired electrical connections are made using the electrical selector should.

The electrical selector described above is used to operate certain reed switches, or groups of reed switches, of the secondary switching devices in a specific order according to instructions previously recorded on tape, with the purpose-encrypted tape being routed to a tape reading device 44. This rope device is part of the Mezzanine invention; it should be mentioned that each course

on the tape one permutation due to the oäev Niuhtporforieyung dsa Banda Esit io'ohe ^ n in

14 -

16A0292 - u-

has eight spaced positions on the side of the belt. The condition of the first five of these hole positions to obtain thirty-two permutations is scanned by the tape reader 44, according to one of the preceding arranged code and by means of a (not shown) known device an electrical connection with a predetermined Clamp the thirty-two "section" clamps 34-

^ and this contact is enlivened, this electrical Connection to the positive terminal of a DC power source (not shown) is made, the other terminal of which connected to earth. Two of the remaining hole positions are similarly scanned by tape reader 44, wherein one of three types according to a code arranged in advance and with the aid of known apparatus (not shown) electrical connections are made: 1) either the "dam" terminal 41 is connected to earth, or 2) the "wire s "terminal 30 is connected to earth, or 3) the" line

The "line" terminal 30 and the "zero" terminal 29 are connected to earth. The hole position remaining on the tape is used for monitoring or checking.

The mode of operation of the electric selector shown in FIG. 3 is described below, it being stated that el ate aloh ^ makes all reedsohultex * de% ^j primary and secondary solvency windings 21 tmd. 2p in the o.iYsnen position

BAB ORtGtNAL

find and that the common shaft of the switching devices 21 and 25 and the switching device 31 is continuously rotated by a motor (not shown).

In the event that the second reed switch of the first goes first of the secondary switching devices and then the second reed switch of the thirty-second and last secondary switching device must be closed, four information characters are required on the tape for this sequence. That Namely, the first information symbol is used to select the first of the thirty-two secondary penalty devices, the second Information character for selecting the second reed switch of this device, the third character for selecting the last of the secondary switching devices ^ uuvl the fourth character sum Selecting the second reed switch of this device is used.

When the first information symbol is read, the first of the terminals 34 - as described above - is automatically activated, with the "dam" terminal 41 being automatically grounded. As a result, causes the constant current generator 40 during rotation of the armature of the additional switching device 31 has a constant current flow in the direction indicated by arrow 45 direction by the electromagnetic coil 22 therethrough, said direction ■ and size of this current are provided such that the reed switch of the primary switch device 21 back into the of-

- 16 -109811/0334

be brought into position; when the first reed switches of the switching device 31 and the switching device 21 of their In addition, an electrical current flows from the first "choice" terminal 34 at the same time to the input of the amplifier 35, whereby an electrical current pulse from the output of the amplifier 35 to the common Point 37 and from there via the common point 39 and through the electromagnetic coil 22 in the direction of arrow 46 -to earth "at the" dam "terminal 41 flows, this current to be overcome of the constant current flowing in the opposite direction through the coil 22 is sufficient and the electromagnet causes the first of the reed switches of the primary switching device to actuate and move it to the closed position bring to; this creates a semi-permanent circuit connection between the common point 23 and the electromagnetic coil of the first (left in Fig. 3) secondary switching device.

After completion of this operation, the tape reading device 44 reads the second information character, which ': now the second of the terminals 34 - as described above - lives and for this purpose the "line" terminal 30 is connected to earth . not shown) armature rotate in phase, comes a moment in which they all the second reed switch of the corresponding switching device 21 or 25 or

- 17 -109811/0334

the switching device 51 enclose. At this moment flows - as above - · an electrical current from the second terminal 34, so that again an electrical current pulse from the Amplifier 35 flows to the common point 37, whereupon this current flows via the semi-permanent circuit connection described above to the electromagnetic coil 26 of the first secondary Switching device and then to the grounded "line" terminal flows. This current flows in the direction of arrow 47 through the electromagnetic coil in question and thus acts on the second Reed switch of the first secondary switching device. This is another semi-permanent circuit connection made within this secondary switching arrangement.

When this process is complete, the tape reader reads 44 the third information symbol, so that the last of the terminals 34 - as described above - animated and to do this, the "dam" terminal 41 is grounded. The further way of working the arrangement is clear, it being only necessary to note that those within the primary switching arrangement 21 beforehand produced semi-permanent circuit connection by the effect of the constant current generated by the generator 40 automatically eliminated and replaced by another semi-permanent stream iaverbindimg is replaced within this circuit arrangement.

can & * af äi © oh @ n toeeehriafceae Wöiso © ine "any

- -IS -

1OiC h

number of the total of 32 by 32 reed switches of the secondary switching arrangements actuated in a certain order and be placed in the closed position, with each operation two information signs and a minimum of two rotations the common shaft of the anchor requires.

All of the reed switches can be returned to their open state together when the tape reader can read an information sign, eliminating the "zero" terminal 29 is connected to earth. In this case, current flows through the constant current generator 28 in the direction of the arrow 48 all solenoid coils 26 connected in parallel via the rectifier 27, the terminal 29 and the rectifier 49, wherein this current is sufficient to power the electromagnets of all Reed switches return the secondary switchgear to their open state sequentially while the armature is moving rotate these arrangements.

The tape reader 44 can then activate another reed switch or group of Actuate reed switches of the secondary switching devices so that they are brought into their closed positions.

It can be seen that the primary and secondary switching arrangements 21 and 25 as well as the additional switching arrangement 31 not necessarily sv / thirty-one Ree & sefealter, - iiidern also: ϊ £ »

8AD ORIGINAL

ne other "any suitable number of switches. The reed switches of each of the secondary switching arrangements 25 do not necessarily have to have the common points shown in FIG. 3, but can - if preferred - be used as individual switches that are not connected to one another.

The intermittently variable resistor shown in FIG. 4 is formed from a switching arrangement according to the invention and has thirty of thirty-two reed switches of the switching arrangement described with reference to FIGS. 1 and 2. The first ten Reed switches, one contact of each reed switch is connected to a common point 60, so that the arrangement is similar to the 3 can be represented as a single-pole ten-way rotary switch, while the contact of the first of the remaining reed switches is directly connected to a common point 61, to which the others also have a corresponding resistance via jfi

62 of the angeoTä-nei ^^ in a graded order of resistance. Fixed value resistors are connected.

The next ten reed switches are similarly connected, where one contact of each reed switch with a common point

63 is connected, while the last of the remaining contacts is un indirectly connected to a common point 64, to which the remainder is connected via a suitable resistor of the resistors 65 arranged in a graded resistance sequence.

One contact of each of the last ten reed switches is ultimately with connected to a common point 66, while the first of the remaining contacts is directly connected to a common point 67

109811/0334 -20-

is connected, with which the remainder is also arranged via a suitable resistor of the series of resistances Resistors 68 is connected.

The common points 60 and 64, like the common points 63 and 67, are connected to one another. The common points 61 and 66 are connected to the output terminals 69 and 70 of the device, respectively, while one of the terminals is one Constant current generator 71 is connected to the common point 61, the other terminal of which via a fixed resistor 72 is connected to the common point 66.

The resistors 62 have resistance values - as shown in FIG visible - between 0.1 and 0.9 of a preselected resistance R at intervals of 0.1 R. The resistors have resistance sizes that range between 0.09 R and 0.01 R with Intervals of 0.01 R. Resistors 68 have resistance sizes that range between 0.001 R and 0.009 R at intervals of 0.001 R.

It can be seen that the device operates when the switching mechanism is operated so that no more than one of the reed switches of each E-series of ten switches works, in relation to the total resistance between the common points 61 and 66, essentially works as a three-decade resistor box , which is any resistance between zero and 0.999 R with the resolution of one part in

109811/0334

BAD original

able to raise a thousand. Thanks to the constant current generator 7.1 the voltage difference between the output terminals 69 and 70 varies in proportion to the total resistance between terminals 61 and 66.

Such a device can be used as a digital-to-analog converter will. A digital code causes a reed switch trio of the switching arrangement to be brought into the closed position where a reed switch has been selected from each of the three decades according to the digital information, then sets the voltage difference between the output terminals 69 and 70 represents the digital information in analog form. The present Device can be one of the most particular in relation to Pig. 3 form secondary switching arrangements 25 described, wherein the electrical selector described there is used to generate the required digital information; however, it can be a any other pulse generator can be used to actuate the switching device of the digital-to-analog converter.

The one regarding Pig. 4 described device can also serve as a generator of a stair-like waveform. It is basically clear that the voltage difference between the Output terminals 69 and 70 will vary gradually when connecting from the reed mounts to resistors 62, 65 and 68 established connections can be changed step by step. Man

- 22 -

109811/0334

- 22 -

doesn’t need anything else to get a staircase waveform at terminals 69 and 70 - wcT bei the waveform ascending and / or descending levels of the voltage difference exists - as a suitable means of temporary Closing the reed switches of the relevant switching device in a suitable sequence; such funds can come from a electrical selector in the general form described with reference to Fig. 3 exist; however, they can be any other shape on v / iron. For example, the apparatus shown in Fig. 4 starts its operation, the first, eleventh and twenty-first Reed switches are closed, and the first reed switch is open and the second through tenth reed switches first closed and then opened one after the other, it can be seen that the between the common points 61 and 66 existing total resistance vary in steps of 0.1 R between 0.09 R and 0.99 R and thereby the appearance of a corresponding one staircase-like waveform between output terminals 69 and 70.

Claims

• - 23 109811/0334 _

BATH

Claims (19)

P B1 tentan sayings 1. Switching mechanism, characterized by a number of Eeed switches (l) arranged at an angle about an axis (2), each of which is put into a first or second state by means of a magnetic field, by means which are assigned to each of the switches switch in the second inflow * to withstand, in which it is placed, and to change by an electromagnet with a rotatable about said axis armature near the reed switch, which is energizable to the Zustsuid of any adjacent reed switch. 2. Switching mechanism according to claim 1, characterized in that sicn the reed switches (1) extend radially from the axis (2). 3. Derailleur according to üiisetzt 1 or 2, characterized in ™ that the means for holding the associated switch in the second state consist of a permanent magnet (7). 4. Switching mechanism according to claim 1, 2 or 3, characterized by means for applying excitation pulses to the electromagnet in synchronism with the armature rotation, in order to achieve the states to change the switch. - 24 - 109811/0334 5 »Switching mechanism according to one of the preceding claims, characterized characterized in that the electromagnet is a fixed coil (9). 6 * switching mechanism according to one of the preceding claims, dtidurch characterized in that the armature has two radially extending Has arms (10,11) which have corresponding pole faces which are arranged with respect to the switch in such a way that the switch located between the pole faces is closed or opened when the coil of the electromagnet is through an electrical Imi:> uls according to the desired state of the switch is energized. 7. Switching mechanism according to claim 6, characterized in that the magnetic circuit of the armature is completed by a sheath (14) which forms one end of the arm (11) of the two arms (10.1.1.) and is coaxial about a coaxial to said axis Shaft is arranged, the sleeve gneten through the coil of the Elektrorru to the other end of the arm (10) of the two arms extends. 8. Electrical digger characterized by a prim-Ire switching arrangement (21) according to one of the preceding claims, and by a first pulse generator for the selective closing of any switch of at least two reed switches of the pri- - 25 10 9811/0334 BAD ORfGlNAL internal device for selecting an electrical connection with a corresponding device comprising at least two secondary switching devices according to one of the preceding Claims, and by a second electrical pulse generator, which is closed by the selected electrical connection any switch of at least two reed switches of the selected corresponding secondary switching device to Establishing a desired electrical connection can be operated optionally. 9. Electric selector according to claim 8, characterized in that at least the strung two reed switches of the primary Switching device (21) with the electromagnet of a separate switching device of the secondary switching devices (25) are connected and that the anchor of the holding devices execute a synchronous angular rotation around the corresponding axes. 10. Electric selector according to claim 9, characterized in that that the first pulse generator has a number of switching means, one after the other and in synchronism with the armature of the primary Switching before direction (2.1) operated and to close a selected switch of the reed switch of the primary Sohaltvorn ^ v / ahlwsiao can be excited 1003 H / im * 11. Electric selector according to claim 9, characterized in that that the second electrical pulse generator has a number of switching means, one after the other and in synchronism with the Armature of the secondary switching devices (25) actuated and to close a selected switch of the reed switch selected secondary switching device can be optionally energized. 12. Electrical selector according to claim 9, characterized in that the first and the second pulse generator have a number of switching means which can be operated one after the other and in synchronism with the armatures of the primary and secondary switching devices, this number of switching means having a common connection, which is electrically connected to the electromagnet of the primary switching device (21) and to a common connection with the reed switches of the primary switching ^{device 4} , these means for closing a selected switch of the reed switches of the primary switching device for selecting a corresponding secondary switching device (25) and for Closing a selected switch of the Keectschalber the selected be η corresponding secondary switching device can be optionally excited. 13 · Electrical selector according to Annpciiüh 12, darliii / üh gnkior that the bassoon iiehalbuilUul o: ui9 Ansah! Reöda ^ kalbsr on i 1 ways by one with the anchors of the primary and secondary »Switching devices with synchronously rotating permanent magnets · can be closed one after the other. 14 * Electric selector according to claim 13, characterized by means that respond to an externally derived instruction to create an excitation voltage respond to one or more selected switches of the real switches of said switching means * 15. Electric selector according to one of claims 8-14, characterized by a neutralization device that can be actuated to flow an electric current through the coil of the Electromagnet at least one of the primary and secondary ^^ ren To send switching devices in a direction opposite to the assigned pulse generator and at least one of the Return the reed switch to the open state. 16. Electric selector according to claim 15, characterized in that the lieutralisationseinrichtung consists of a constant current . generator (28) exists. 17. Electrical selector according to claim 15, characterized in that a first constant current generator »tor the primary switching device and a second constant current generator of the secondary - 28 109811/0334 - 28 switching device is assigned. IS. Electric selector according to claim 17, characterized in that the coil of each electromagnet of the secondary switching devices is connected in series with a device for conducting current in one direction, the coils of the secondary switching devices and the associated device ^ for conducting current in one direction for receiving a parallel circuit are connected in parallel and the parallel circuit with the second constant current generator between the first
and second terminals are connected in series. 19. Intermittently variable resistance, characterized by a Switching device according to one of Claims 1-7 and by a series of at least two fixed value resistors (62), wherein one of the terminals of each of the fixed value resistors with a corresponding switch of the reed switches of the switching device ^ is connected. 20. Intermittently variable resistance, characterized by a Switching device according to one of Claims 1-7 and by at least two rows of fixed-value resistors (65), each Series of fixed-value resistors has a number of such resistors, which are arranged in a graded order of resistance are arranged and each of which has a corresponding switch - 29 ^109811/0334 BADORIGtNA. the reed switch is uniquely assigned to the switching device while one of the terminals of each pest value resistor of each row has a first common point (66) thereof Row and the other terminal is connected to one terminal of the corresponding reed switch, the other terminals to One terminal of the respective reed switch is connected and the other terminals of the reed switch are connected to each row of pest value resistors are assigned, with a second common point (67) of each row and with the first or the second common point of the next row in such a way that enabled by the actuation of the switching device becomes that any pest value resistor from one row with any pest value resistor from the next row can be connected in series. 21. Digital-to-analog converter, characterized by an intermittent variable resistor according to claim 19 or 20 and by a pulse generator for actuating the switching device in at least an angular position of the anchor3 according to preselected information in digital form, the fixed resistances are chosen so that their effective Wide rabarid represents the preselected information analog in digital form. 22, a staircase waveform generator through an intermittently changeable opposition bound naoh claims - 30 1098 11/0334 19 or 20 and by means for temporarily closing each of the reed switches of the switching device in a suitable sequence, and by means for sending electrical current through the intermittently variable resistor, the im exposed to a variable resistance, the voltage difference developed has the desired shape. I 0 ') Hi 1/03 3 4