DE2016308A1 - Magnetically operated protective tube contact - Google Patents

Description

DIPLiNaHANS W. SCHONINÜ —2. APR 1970

MTENTAMWALT "Ο · HAMBURG 1

te SI

(0411) »WM BRIOGS & STRAMOH CORPORATION

2016 308 3300 North 124th Street

Wauwatoea, Wisoon, USA Attorney File: 2554

Magnetically operated protective tube contact ο

The invention relates to a magnetically actuated protective tube contact (reed contact), with the larger one Power can be switched on and off with large, different switching frequencies,

Magnetically operated protective tube contacts have been known for many years as a valuable component for many applications. In the Praxiö these contacts were, however, applied only limited, as they are not in de ^ location, large _f leistungan to turn properly and not enough frequent intervention precisely on the construction and dismantling of changing short-term areas of activity. As an improvement to the epheb- ^ lioh®, for example, a Seirat ^ pipe contact recently appeared on the market , which enables 240 stopping operations per minute with a cut-off current of 3 A with 125 7 or 2 A with 250 V alternating current.

With this contact, the high holding frequency was to a considerable extent in favor of the greater switching capacities

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UIZtONIl »ANK, KSiSiS-JjS. iJS3-3 ■?) 3T »CHfCK HAUaUBQ HHH

sacrificed because older protective tube contacts for lower ones Performances enable up to 60 switching operations per second,

For numerous applications (e.g. in computers), thermowell contacts would be desirable, their switching frequencies the 240 switching operations per minute of the aforementioned protective pipe contact many times over. In many cases (e.g. machine tools' control systems) required that considerable Be over 100 VA. In all of these cases, you would Use thermowell contacts if you can use them without any loss other promotional signatures would be available.

A protective tube contact should be used for the best possible applications can take into account high switching frequencies and large switching capacities with a long service life »The the aforementioned protective tube contact recently released on the market « have a leg after Biuiohoriijen advertisements of only 5,000,000 switching operations in one Pi tui 3 A and 120 7 Wachnelstrom, Bei hnhon fichaLtüreciussHiä «n you would serve an extremely short one Loves mudauor corresponds, with 240 sliding curtains each Minute for example less than 40 hours,

The protective tube contact of the applicant according to the German patent specification 1 279 190 works in a very precisely defined way

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Switch-on and switch-off times "at switching frequencies of more than 200 per second and also at lower frequencies · Even if the teaching of the German patent = font 1 279 190 enables very high switching frequencies, it does not yet solve the long-standing problem with a protective tube contact at high switching frequencies * to switch large capacities "

The aim of the present invention is above all an i

considerable improvement of a protective tube contact according to the German patent specification 1 279 190 to the effect that besides a switching frequency corresponding to the state of the art, it also has an expected service life of hundreds of millions of switching operations, breaking capacities in the order of 1500 VA controlled.

To respond safely to changing magnetic fields

in I.

EU, the / opening direction should be effective forward «= · voltage äej tongue or tongues of the protective tube contact be very low. To close and open in a precise temporal relationship to emergence and disappearance With rapidly changing magnetic fields, the normal air gap between the contacts should be relatively small be. A contact that meets these requirements has a relatively weak contact in the closed state

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Contact pressure. In order to avoid high contact resistances BU in this case, use previously known protective tube contacts generally copper or precious metal contacts in a protective gas environment. If such contacts When operated with high power, they often tend to stick and erode. For these reasons it was previously believed " that high switching capacities are not possible with protective tube contacts are possible, especially when the switching frequencies are high.

Many causes of contact sticking can be eliminated by inserting tungsten contacts a Hoohvacuum to work o Because of their high At the melting temperature, tungsten contacts can switch higher currents than other contacts in a high vacuum

without arcing or welding between the contact surfaces. · Paths The hardness of tungsten also makes it stick Contact due to friction is very unlikely.

However, if the opening force at the contacts is limited, as is the case with protective tube contacts, tungsten contacts tend In high vacuum when high voltages are switched off, again under the influence of electrostatic attraction to close »In order to understand this reclosing, it must be borne in mind that almost all circuits have more or

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are less inductive and that tungsten contacts are separated from one another in a large yacuum without a light base destroying the circuit energy now close the contacts by the electrostatic charge between them again or not depends on the available mechanical energy that the contacts trennto When the contacts wieds.z can sahließen? ₉ sufficient iin general, the large caused by the StrOmkreiakapaaitäten Stoßstroai to the Melt contacts and weld them together.

Because of the above phenomena, the protective tube contact according to the invention should not only respond to relatively small actuation forces ₉ but also in

be able to work without gluing and welding and without (|

Isolation due to electrostatic attraction with high switching frequency to separate circuits that leave very high potentials at the contacts.

The switching blade a reed contact is a coordinated device, which vibrates with any natural "frequency and therefore a function of the

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Frequency of a cyclically built up and reduced magnetic force field responds differently, depending on the frequency of the change in the magnetic field is phaeengleiobic with the tongue oscillation immediately after a previous contact movement or not.

In this context, the inventive Protective tube contact oo be designed that it reacts to a cyclic magnetic field of any frequency up to a maximum value j provided for the contact because it is a few hundred Hz, responds precisely.

It is also important that a protective tube contact when closed has a relatively low contact » has resistance, so that it is voltage operation even for Ilied, in which the contact resistance is minimal must be held, is suitable "

The service life of a contact depends mainly on the cut-off current, especially if the contact opening always takes place with the same current direction, as te is the case in DC circuits.

It is known that also with all Uohtbogenfrei Contact openings between the contacts a certain

009846/1564

Matarial transport occurs. This arc loee Material transport, which is known as the "KiedertensionB-Phenomenon" always takes place from positive contact to negative contact * This phenomenon also occurs Tungsten contacts in air or high vacuum and also with other metal contacts in any environment. With pure direct current operation, the arc reading material transport always takes place in the same direction, see above that the material portals of the individual opening processes add up and the service life of the protective tube I contact depends on the amount of contact material and the cut-off current. An equal contact lh a comparable alternating current circuit normally has a considerably longer service life since it does not always switches off at the peak current and each individual contact is positive only every second time on average is so that the material transport In changing Directions take place and largely compensate each other again. I.

The protective tube contact according to the invention should therefore ^{, if possible, overcome the disadvantages of the so-called "liedersspannung8 phenomenon n} , so that it has an extraordinarily long service life even when operated with high direct currents

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Κο? Ί ·; '·; - ·' ■■. ■ - ^: ·., Ν, Λ possible I: .ir --.-: t't) ..-;> enu :: ·. luur; g iu considerable 'Μ?.!? -'- · "^ - ■ ■:;: ⁴ α1λΞ ^ i je3ei £;>~; ^{! r} il ! v'jf faung occurring Wgfr-r.1,: - . "" .. :: .. ■ ai- :; '_£; ort ve: s pos; ΐΐτ & α äuü- ne £ ati? Erj contact vprsehl οϋί: ί: ,, no that the experienced contact has a very long service life even with Eocal ^ l ^ tunge-Sieichatroznbetrieb.

The protective tube contact according to the invention can also implement the teachings of German Patent 1,279,190, so that the contact tongues normally rest against an abutment with a precisely defined preload. To solve the above-mentioned problems and to eliminate the disadvantages mentioned, the protective tube contact according to the invention asked for an auxiliary contact on one of the switching tongues which protruded towards the other switching tongue and which was supported on the switching tongue carrying it with a bias acting in the direction of the other switching tongue. The auxiliary contact is preferably a resilient, bow-shaped molybdenum wire, the legs of which are bent in a U-shape, the bent leg ends being attached to the front side of the switch tongue facing away from the soling rod, while the leg parts grip the switch tongue laterally before the bend, on the rear side of the switch tongue facing the stop rod and converge in front of the switch tongue end to form a web-like contact surface protruding towards the other switch tongue _a

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More Sinsellielten and features of the ■ Bs? Fiiactag will become apparent from the following detailed description and the accompanying drawings, eat which preferred embodiments of the invention are for example illustrated ₀

In the drawings show:

. 1 is a partially broken away side view

of a protective contact according to the invention in open position,

Pig. 2 shows a representation of the Pig · 1 similar to Contact in closed position,

Pig. 3 is a disassembled perspective illustration of the components of the erfindungsgsäßets Contact without outer covering,

Pig «4 a top view of the contact tongue with auxiliary contact,

Pig. 5 is a sectional side view of a contact tongue of the protective tube contact according to the invention on a larger scale,

Pig. 6 is a diagram showing the relationship between temperature and linear expansion each of the three metals represents that for the contact tongues of the protective tube contact according to the invention it can be used and

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Pig. 7 shows a diagram of the forces acting on a protective tube contact designed according to the invention.

You pig. 1 and 2 show a protective tube contact according to the invention 5 with two elongated, resiliently bendable, magnetically permeable tongues 6 and 6 *. in an elongated Housing or protective tube 7 · The protective tube is evacuated to a high vacuum «At the sealed ends of the Housing 7 protrude two elongated silences 8 and 8 ', which carry the two tongues 6 and 6 * and on their outer ends formed as connections 9, 9 'of the contact are·

The tongues 6 and 6 extend ^{axially inward from the pins 8 and 8 1} , where their free ends overlap in the longitudinal center plane of the housing and are there transversely spaced from one another by a predetermined amount in order to form a contact gap 10. Under the influence of a magnetic field extending over the tongues 6 and the gap 10, the tongues are bent so that their overlapping ends make contact.

The pins 8, 8 * also have an elongated, relatively stiff stop rod 11 and 11 'at the inner end.

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Bie rods 11 w & ä 11 ° I3 © f imSeia si © fö ö © ies V "@sa% a remote side iss? SmageB M msMM ⁿ .o 2a € i © flat Hetallst2? El £ © m $ inä _t Ismm eau full too als fortea? « mtä ES © & s @ it © front side shows-.snm KoätaMgfalt iö mg II © fiü © iss © £ t @ braces itself on StaVH ·

Normally you press on pliers at your own pace stab with the inherent bending stress, so that slab according to the teachings of the aforementioned Asutoahea patent 1 279 190 an outward bias on the Stop rod results. The last-mentioned German patent lays down the advantages of such in detail Arrangement in connection with protective tube contacts for high switching frequency.

According to the present invention, the tongue 6 carries an auxiliary contact 12, which is normally on the rear side of the tongue 6 with the bending chip | voltage rests and has a web 13 which projects beyond the free end of the tongue 6 and has a distance from the tongue 6 * which is slightly smaller than the width of the Kontaktspalteβ 10 zwleohen the free ends of the switching tongues 6 and 6 *. The auxiliary contact 12 serves several purposes and has among its tasks, snagging the Schut "pipe kontaktee to prevent high current surges _β

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The protective tube contact will now be described in more detail o The housing 7 is preferably a glass tube section, the opposite ends of which are fused around the pins 8 and 8 'to fix the pins in an essentially coaxial alignment and to hermetically seal the housing »

The stop rods 11 are welded to the inner ends of the axially widely spaced pins 8. The pins 8 could just as well be an integral part of the stop rods "The stop rods extend to the free ends of the switching tongues". As German Patent 1,279,190 explains, the stop rods can be made of either magnetic or non-magnetic material, they should but in any case be considerably stiffer than the reeds "

According to the present invention, the tongues 6 and 6 * consist of a substantially flat foot part at the clamped end, a substantially flat head part 16 at the free end and an intermediate neck part 17 which has a slightly smaller cross section than the foot and head parts. The neck part is an integral part of the head and foot parts at an obtuse angle. The foot part 15 covers each tongue in the

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Got the clamped ice end f Xaehliegeiad. d @ a bart en carrion stick and the l © teterea ₉ "for example- * by Sonw @ ißung _p ' ψ esbtmdett * Si® ¹ HalstslX protrudes obliquely forward from the stick in. Egg deadmag' to the free end of the tongue <> the head part 16 is normally "inclined towards the stop bar, with the tip of the tongue acting on the stop bar with its bending stress acting in the opening direction"

The tongues according to the invention should have the greatest curvature on the neck part 17, so the neck part has a reduced cross-section _{or the} gate is only reduced in thickness ₉ so that the tongue has a relatively flat spring characteristic and the bending forces in the tongue are relatively steady when the door is closed Contacts increase »The meaning of this measure results from the Pigο 7» in d @ r the forces acting on a tongue of the protective tube contact of the invention are shown when |

the tongue magnetically into the contact closure If the magnetic field that actuates the contact is created, the field strength is reached a value at which the attraction between the tongues » tips becomes so large that their biases are overcome and the tips of the tongue move towards each other move ,, After reaching this value, the ·

00984671 564

On eijiajri ^f irri'b:? W ^ "- .; '.' ■: ■ ·; ύ «ΐ · Zm & en much « faster than Λατ ■■,: <A * / y ^ '. in:' · K -.; - ifetfluss ,, so that the latter than Γ ..- "···:; - . ■■ ... - ^ ₄ , 3sh-33ä Herd kaim _o Under this assumption, the change in the saagpetic forces of attraction (Fig, 7 curve 26) is due exclusively to the approach of the tongues inversely proportional to the change in the stray flux field between the tongue tips, so that curve 26 is essentially parabolic. "The bending forces in each tongue (curve 24) increase linearly with the bending path of the tongue tips.""The difference between the magnetic force and the bending force is the one available in each case Force that can accelerate the tongues at the moment o If it is a tongue with a flat spring characteristic, the differential force increases very quickly when the tongues move towards each other, so that the tongues approach with steadily increasing acceleration »

By the fact that the bend of the tongues is essentially up the neck portion 17 is limited and that essentially only the head portion 16 moves, the tongues speak on a magnetic field very β without11. Since the Masee of the When the head section is small compared to the mass of the entire tongue, the head section becomes slightly larger than the rest of the tongue Contact closing and contact opening to take effect

009846/1564 ' _BAD original

Menden magnetic and BiegsfaSlfte "accelerated _o -IAb at a tongue of substantially gleiehfSrmigex" Meke corresponding to the most Msherlgen SehtttsrohrküÄtakten a comparable low Irägheit "to evreiohen would very briefly turn the tongue would thereby but so stiff" that its spring characteristic, the l & gnetkraftkurve intersects so that the tongue can then no longer be brought into the contact-making position by a magnetic actuating field _P

The neck part 17 of each tongue runs at an angle to the head part 16 (in order to reduce the contact impact * when the tongue tips touch each other Head part runs _p such a vibration has a considerable component in the longitudinal direction of the neck part o The head part is also relatively short ο For these reasons, the frequency of such a tongue vibration due to contact rebound is very high with ™

relatively small amplitudes «Such high frequency. Oscillations "conditions consume energy very quickly" especially because of the small amplitude even a little energy to destroy _o For all these reasons the On · "bulging in an inventive reed relay in practice is not a problem, even at the high closing speeds result at high switching frequencies * _Λ

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Veretändlioherweise result from the arrangement of the stop or impact rods, on which the tongues rest with pretension, small impact phenomena and small contact gaps 10 and it is also possible for protective tube contacts with a high switching frequency to use tongues that have a small spring constant ₀ without The contact rods 11 and 11 * would each open the contact would result in a long-lasting, high-amplitude, low-frequency oscillation of the relatively easily movable tongues, which would no longer be compatible with the temporal course of rapidly successive contact closings Low amplitude oscillation, as also described in the aforementioned German patent specification 1 279 190 *

Ba, the tongues when the contact closes meet with considerable force, the front sides of their tips, d "h _o their contact surfaces 18, provided with a tungsten coating," The hardness of this tungsten coating leads to high mechanical wear resistance and prevents the tongue tips adhere to each other remain by cold welding or mechanical friction. Because of the low current flow between the contact surfaces 18 when closing and opening and because of the auxiliary contact to be explained below, these contact surfaces tend primarily because of the high

009846/1564

Melting temperature of tungsten not for welding> Because of the oxygen-free environment, the tungsten contact © surfaces 18 of the contact according to the invention also occur to no oxidation, so that the contact resistance during the service life of the protective tube contact remains short: and does not increase, as is the case with people working in the air Contacts of the Pail is »

On the tongue 6 ^s must as a counterpart to the web 13 of the |

Auxiliary contact 12 can also be provided with a tungsten contact surface 23 for reasons to be explained below. This tungsten contact surface 23 can be a continuation of the tungsten-coated contact surface 18 at the tip of the tongue (3? Ig _e 3 and 4) »

The tongues 6 and 6 'have in the opening direction a certain bias voltage have through which they are normally held at the stop bar ₀ The protective pipe contacts * be ^fi with the tongues 6 "6 °, the Asischlagstäben 11, ^β 11 and the terminal pins 8 ₉ 8 necessarily au subject to considerable warming at certain points in time during manufacture. If the ends of the protective tube are melted to the connecting pins 8 and 8 'during the last stage of the protective tube contact assembly, a certain heating of the tongues cannot be avoided. However, heating of the tongues is

009846/1564

also desirable in order to degas them and to ensure that the tongues do not give off any gases that cause the high vacuum of the protective tube.

But if you keep mono-metallic tongues open longer Normal glow temperature or above, the gate tension directed against the stop bar is lost.

Bimetallic tongues, on the other hand, can be given a desired pretension by heating. Two metals have now been found whose properties complement each other in a remarkable way and they work together in such a way that particularly advantageous bimetal tongues are produced. The one metal, which is traded under the trade names "Therlo", ^w Kovar ^w and "Rodar" and is to be generally referred to below as "Zegleruog V ", consists of:

28.5 to 29.5 pounds nickel)

16.5 to 17.5 * Cobalt! ^^^ _κ

max. 0.5 ¹ P Manganese/

Remainder iron I.

The other metal, which is also traded under the trade name "Niromet 42", consists of:

40.5 to 41.5 5 * nickel Ί

max. 0.02 # carbon!

max. 0.25 # silicon j

Remainder iron J

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You se two alloys * denoting below and in Figure ₀ 6 alloy K and alloy H "have ground _t high magiietlsöße Istaktien and low remanence ₉ they SSB Bind particular well suited as Leglerungskombination in a reed relay," do you have for this £ w @ ck also sufficient spring properties® The particular usefulness of this special alloy pair for the elements of a bimetallic protective tube contact is based on the thermal expansion.

In a Temperaturhsreieh won room temperature to about 320 ° C the alloys described have SWEi sahesu.

same coefficient of linear thermal expansion®ώ ₉ ^:

.so that one made of these metals © teig® itee

Pretension itself a © i the greatest expected |

Fluctuations in ambient temperature, in üenen @in.

Protective tube con ^ alcfe will work, not äadsrt _o Furthermore, within this temperature range, the expansion of the alloys is almost the same as that of tungsten ₉ so that the tips of bimetallic tongues made of these alloys can be provided with a tungsten coating on the contact surface 18 without

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to have to fear that the tungsten coating at Temperature fluctuations bend the tongue head parts and change the preload.

As can be seen from FIG. 6, the expansion-temperature curves of these two alloys are essentially linear in the aforementioned temperature range. At about 320 ° C, however, the expansion curve of alloy Ef corresponding to a higher extent of bends upward to d $ nn above to become linear again of 370 ° C at a greater pitch than in the initial region of below 320 ° C ₀ The corresponding curve for Alloy K continues to run essentially linearly up to a range of 400 ° C, then becomes steadily steeper and above 450 ° 0 again linear and parallel to the upper part of the curve of alloy EF «

According to the present invention, elements of alloy H and alloy K are connected to one another for the production of bimetal tongues and then rolled out to the desired thickness to form a strip from which the tongues can be punched o The individual tongues are fastened so that the alloy V. layer for The stop rod shows and is applied there with a pre-tension that is considerably greater than the pre-tension desired in the finished protective tube contact ο The tongue arrangement is then set to a temperature _B

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ale well above 450 ° O "" preferably at 760 ° C or higher, warmed

The maximum Erwännungetemperatur igt not critical ,, as long as the tongue / is not poor so v that it can no longer absorb deformation forces ₀ Time held his tongue at maximum temperature, just · = if not critical Preferably, jedooh heating in the high volume at such a high temperature and for such a long time that there is sufficient degassing _β

When the temperature of the tongue of 320 ° C to 430 ° G rises _9, dl © IiSgiearang dehiQt: 3Ϊ on the tongue back faster than dio Ütagieneag K ₉ G® AEAs ei "rope of the initial bias voltage, with which press the tongue against the Anschlagatab o If the temperature is increased further to the maximum value, the tongue is completely free of tension and remains g

then lie on the stop rod without exerting a pretensioning force on it.

When the tongue is cooled from the maximum temperature to about 430 ° C, there is no tension in the tongue, since the two metals from which it is made contract again in the same way _β at 430 ° C and

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including the tongue erhetliohe voltages can endured in the range of 430 ° E to 320 ° E, the alloy N shrinks faster than the alloy K ₅ that the tongue is pressed by bimetal against the stop bar with a bias voltage Ue is relative to the Thicknesses of the two alloys that form bimetal can be precisely determined. If the two metals expand and contract equally at temperatures of 320 ° G and below, the preload remains constant at all temperatures between 320 ° O and room temperature.

It has already been mentioned that the tongues on the soling rod initially have a considerably increased pretension must be attached so that the tips of the tongues do not move in the bimetallic deflection Lift the temperature range from 320 ° C to 430 ° C from the stop rod * If the tongue tip is too small because of it The initial pre-tension could lift off the stop rod, would be the pre-tension existing in the final state of the tongue undefined as it is partly due to the unknown distance between the tip of the tongue and the Stop rod at temperatures above 430 ° C depends. Unless the initial preload is just great If enough is chosen, it is not critical, since the pretensioning of the tongue in the final state is only one The function of the bimetallic deflection is.

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Understandably, the bimetallic tongues according to the invention can not only be produced from the defined alloys N and K. In any case, one of the metals forming the tongue must be magnetically permeable "certain temperature be similar to each other, which temperature is in a range which can absorb stresses in the both metals," etc. in addition,

need the thermal expansions of the two metals in an area that is above the aforementioned SJempe » rature is different, in which case the metal that has the greater linear expansion in this area has to be arranged next to the stop rod Tongue according to the present invention when one has a strip of alloy H on one side in its entirety Length with a tungsten coating, which forms the front of the tongue, since tungsten is the smaller "

linear thermal interpretation in high temperature » area has «

While the switching speed of the protective tube contacts according to the invention depends to a considerable extent on the prestress with which the tongues 6 and 6 * rest on the stop rods 11 and 11 · _p is the VA load capacity

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of the protective tube contact primarily from the auxiliary contact 12 of the tongue 6 dependent, the auxiliary contact 12 but also has other important functions to fulfill «,

The auxiliary contact should be sufficiently resilient and light in weight so as not to significantly increase the hatred of the tongue 6 that carries it. These requirements are met particularly well by a molybdenum wire , which also has other important advantages described below.

The auxiliary contact 12 made of molybdenum wire is deformed into an elongated U, the outer legs 19 of which are bent back inward again, so that arches 20 and coplanar retaining lugs 21 are formed, which are formed by the ends of the wire ₀ These retaining legs 21 lie flat on the front side of the Head part 16 of the tongue 6, where they are welded or otherwise attached. Because of the bends 22 in the outer legs 19 of the auxiliary contact, the holding legs 21 and the arches 20 are slightly in front of the level of the rest of the lightness of the legs 19 The leg points between the bends 22 and the yoke part 27 of the auxiliary contact form a peder arm, which forms the back of the head part 16 cover the tongue

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and normally lie there with pretension «. On the yoke part 27, the distance between the outer legs 19 of the auxiliary contact is considerably smaller than the width of the tongue *. Towards the neck part 17, however, the legs 19 diverge considerably and then protrude laterally beyond the tongue ₀

The yoke part 27 of the auxiliary contact is at right angles bent over outside in front of the tip of the tongue β and carries

the contact web 13o the yoke part 27 also protrudes *

yet the front of the Zunge§ so that in the normal open position of the reed relay s © the distance between the web 13 and the tongue 6 ^e is less than the distance between the actual Zungenο

When the tongues move towards each other under the influence of a magnetic field, the contact web 13 of the auxiliary contact acts on the contact surface 23 of the tongue 6% before the contact surfaces 18 of the actual tongues come into contact with one another the tongue 6, the force to be overcome when closing the contact is greater when the auxiliary contact 12 touches the tongue 6 ' _o When the auxiliary contact 12 touches the tongue 6 *, it thus acts resiliently against the magnetic attraction acting on the tongues

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according to the bending force of the tongue 6 and the Bending force of the auxiliary function 12 · Figo 7 shows the Bending forces of the tongue in curve 24 and the additional bending forces of the auxiliary contact in curve 25. It can be seen that the stepped curve 24 »25 of the combined bending forces better follows curve 26, which reflects the magnetic forces acting in the contact-closing direction *

When the tongues approach one another under the influence of a magnetic field, there is a strong acceleration right at the beginning of their movement. Therefore, the tongues have a considerable moment when the auxiliary contact acts on the tongue 6 * Time very large compared to the bending forces counteracting the magnetic force ο Since the auxiliary contact has a forward bias, the inertia and magnetic forces together almost completely suppress the impact between the auxiliary contact and the tongue 6 *. The small vibrations that occur immediately after the impact of the auxiliary contact β on the tongue 6 ^B have a very high frequency and a small amplitude because of the rapidly growing contact pressure between the auxiliary contact and tongue, so that these vibrations die away very quickly *

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Even as the help contact 12 touched the tongue 6 * the head parts of the two tongues move very quickly towards one another, whereby the total spring force opposing this converging movement does not grow as quickly as the magnetic force that the tongues draw towards one another (3? Ig. 7) For all these reasons, the head parts of the tongues tend to have very little impact when making contact. But even if the head parts would rebound, the protective tube contact g would remain closed, since the auxiliary contact ^{presses against the tongue 6 fi} with a force, you im essentially the same as the preload ₉ with which it normally acts on the tongue 6.

The strongest bend at the auxiliary contact takes place in the curved part 20 close to the neck part 17 of the tongue _0. Therefore, the contact web 13 of the auxiliary contact and the head part 16 of the tongue 6 tend to vibrate

a common center of oscillation, so that the "

Web 13t once it has acted on the associated contact surface 23, bat ₉ practically cannot grind on this surface, even if the head part of the tongue 6 continued to vibrate

When the protection tube contact according to the invention is complete is closed, the contacts of the two tongues produce

009846/1564 ^ o original

ie the tungsten contact surfaces 18 a second current path, which together with the contact surfaces 13 and 23 of the Hilfekontakteβ and the tongue 6 * gives the protective tube contact according to the invention a relatively small Cteeamt resistance, so that the protective tube contact is suitable for both low-voltage operation and high-performance circuits.

Although the help contact 12 is very important for preventing rebound effects and for generating a low overall resistance at the closed protective tube contact, it may have even more important tasks to perform when opening the switch _{or the like}

As mentioned, the tongues of the protective tube contact according to the invention have a very flat and relatively weak spring characteristic, so that they respond immediately and quickly to a rapidly developing magnetic field. Protective tube contacts in circuits with high power tend to stick when opened.This is a problem that is difficult to solve even if the contacts have a high melting point and work in a high vacuum, since tongues with low stiffness alone cannot rub sufficient contact breaking force in order to connect a relay large Ijpißimg j? u interrupter », Bf i dom exfiru unßößf ^ m-en L-chutzrohrK>nta> rt is gluing through the auxiliary nl ontn? ■ i

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When an actuating magnetic field is removed, the separation of the tongue tips of the protective tube contact leads to an increase in the total resistance so that. A certain potential difference occurs at the contact surfaces 18. However, the protective tube contact still remains effectively closed because the auxiliary contact 12 is applied to the tongue 6 *. For this reason, the electrostatic attraction between the contact surfaces 18 is negligibly small and cannot interfere with the rapid separation of contacts ₀ i

When the tongue 6 moves back to the stop rod 11 ₉ it reaches a high speed, as it is accelerated by their own flexure force and preload of the auxiliary contact. When the tongue 6 again touches the limbs of the auxiliary contact 12, it has a very large moment _s so that it literally strikes the auxiliary contact 12 away from the tongue 6 and

the adhesive tendency of the contact surfaces 13 and 23 ent · "λ

counteracts α by this abrupt strong contact separation when opening the switch, the inventive Protective tube contact Voltages in the order of magnitude of 3000 V at 0.5 A even with voltage peaks up to approx Interrupt 15 000 V.

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The current that is normally to be interrupted determines the expected service life of the protective tube contact. It has been shown that the protective tube contact according to the invention has a significantly longer service life than previous Schutarohrkontakte, even if currents in the order of 5 A are to be interrupted, at 0.5 A direct current, a protective tube contact according to the invention was still usable after more than 200 million Actuations · With lower currents, the service life increases approximately linearly inversely to the magnitude of the current.

The special metals of the contact surfaces 13 and 23. As mentioned above, the contact web 13 is an integral part of the auxiliary contact, which consists of a one-piece piece of molybdenum wire and cooperates with the tungsten contact surface 23 of the tongue 6 *.

If both contact surfaces 13 and 23 are made of tungsten and work in a high vacuum , they open spark-free and without arcing: but when the contact opens, a certain amount of tungsten is transferred from the positive contact to the negative contact. This material transport to the negative contact is the so-called low-voltage phenomenon in the arc-free and spark-free separation of tjfcromfUhrentlen switch contacts. Dor

BAD ORiGlNM-Q 0 U fj / »6 / I Γι ö 4

The reason for this is well known. When two contacts separate without arcing, the first rises Contact resistance increases very quickly, during the Eontalrfc-; pressure becomes smaller When the contact pressure becomes zero, the contacts touch on an infinitely small area over which the entire current of the circle flows got to. The energy then stored in the contact material In this very narrowly limited space, the contact metal heats up above the melting point, which is so high Melting point may also be. That way "

molten metal particles are used for a short time Momentarily held in their position by surface tension and then bridge the separating contacts But if the contacts then diverge further, The surface tension collapses and the metal particles eu fall behind the contacts. Because the positive If the contact is hotter than the negative, the largest part of the molten metal is collected on the negative

Contact to «. Even if the amount of metal used in each g

Opening process is transmitted in this way, relatively klein istj it changes more or less immediately proportional to the size of the switched current »

S.

When the erilnduugsgemäüe stake is located in a DC circuit or in a circuit in which the _s

BATH ORIGINAL

i: Γ Sc * ii i ι ν 1

Current at switch port always flows in the same direction, the reed contact should be connected so that poeitiv and its terminal 9 * negative eats at the Sohalteröffnung its terminal 9, the molybdenum contact surface 13 that is positive and the tungsten contact surface 23 is negative "If these contacts open _P Molybdenum initially transferred from the contact surface 13 to the tungsten contact surface 23 due to the usual low-voltage phenomenon.If the contacts then diverge further, the molybdenum bridge between the two contacts reaches the breakdown point and a voltage difference arises at the contacts. Due to this voltage difference, the melted molybdenum releases an excess of electrons on the negative contact, which this point

locally more intensely heated, so that in the space between Ionized molybdenum is emitted at the contacts o

Between contacts not a complete plasma arc, but obviously on the! Ecause the contact surface 23 on which the molybdenum was transferred _c a kind of cathode spot, from this cathode spot most molybdenum ions are emitted created ₉ then to the anode, d _o h <for contact 13, from which they came and from which they were transferred as molybdenum, migrate. Because

BATH ORIGINAL 009846/1564

There is no oxidation of the high volume surrounding the contacts, so that the evaporated molybdenum again is deposited on the molybdenum contour 13 and there easily adhered

This will ensure the arc-free transmission of molybdenum from the contact surface 13 to the contact surface 23, which in the initial phase of the

Contact separation occurs ₀ largely back up _north

raised or compensated by the reverse transport of molybdenum " during ionization in the immediately following phase of contact separation

The tungsten does not take part in the described transfer ρ because its melting and evaporation temperatures are considerably higher than those of the molybdenum and because in the very first phase of contact separation the arc-free transfer takes place right at the tungsten contact _B so that the molten molybdenum | is deposited on the tungsten "The power ratings of the reed contact according to the invention the properties determine the molybdenum, the temperature of the cathode" fleckeβ, d ₀ h _o it is not enough energy available to ionization of the tungsten to cause ₉ after dae molybdenum evaporated once from there is.

009846 / 156A

The above explanation of the long service life of the protective tube contact according to the invention for DC circuits may be incomplete and in some points also inaccurate, but in any case the results obtained with this protective tube contact arrangement according to the invention are certain Contact phenomena and the associated generally accepted Theo centering _o

The above explanation is obviously also confirmed if a protective tube contact according to the invention is incorrectly switched on in a direct current circuit, i.e. it is switched on in such a way that terminal 9 becomes negative and terminal 9 'positive. Under these conditions, the negative molybdenum contact 13 becomes much colder than the positive one Contact, so that tungsten is deposited on the molybdenum contact and the protective tube contact has a significantly shorter service life than with a proper connection. The protective tube contact fails as soon as the tungsten contact is perforated or eroded to such an extent that the underlying material is exposed and the contacts get stuck due to welding or mechanical friction ₀ Under these circumstances, the tungsten cannot be transported back because of the particularly high evaporation temperature of tungsten, which is in the power range of the protective tube contact prevented the formation of an effective cathode stain

009846/15 6

The Riehtigkeit above explanation is confirmed by the fact _t that the reed relay according to the invention at low voltage operation in Achwach inductive circuits - and even if it is connected properly - a much shorter service life has inventive than When one in circles greater achievements in the nominal range of the reed contact ₀ Protective tube contact, for example, in an induction-free circuit with a cut-off current of 2 A and a voltage of 1.5 V g

used one notes that the molybdenum is continuously transferred from the positive contact surface 13 to the negative tungsten contact surface 23 without it being transported back.It should also be mentioned that protective tube contacts ic such circuits ^ 'for example heating circuits, but offer no special gate parts even under these relatively poor conditions, the 'life of the reed contact according to the invention nor a Hehrfaches of the _nine is what you f with previously known conduit contacts

can reach·

The long lifetime of the invention & Sen protective tube contact is caused apparently by the distance or _0, the temperature difference between the melting and evaporation temperatures of the two contact surfaces 13 and 23

009846/156 / »

forming metals and by the hoobvaouum in which the contacts work. In a protective tube contact working according to the basic concept of the invention, contacts made of other metals can also be used, provided that the material of the negative contact does not allow an effective cathode spot within the nominal power of the protective tube contacts, while the material of the positive contact in the high vacuum provides such a cathode spot. However, tungsten and molybdenum are preferred metals because they both melt at very high temperatures and prevent contact whitening, and because both are hard enough to counteract mechanical wear that could cause friction sticking.

Even if the contact pair of the protective tube contact according to the invention, consisting of tungsten and molybdenum, undoubtedly has a greater resistance than contact pairs made of softer metals, the other facts mentioned above compensate for this property, so that the protective tube contact according to the invention also has a relatively low effective resistance _{or the like}

Understandably, the according to the invention also has Protective tube contact does not have an eternal service life, because one

009846/1564

certain amount of molybdenum that occurs at each opening of the holder is evaporated, is also reflected on the wall of the ■ Protective tube 7 down, and it is also not all of the molybdenum transferred to the tungsten contact surface 23 picked up again by the auxiliary contact. Understandable catfish can molybdenum precipitated in places an. that has never been molybdenum before, not an participate in the Kathödenfleek evaporation and thus also do not migrate back to the molybdenum contact «» Thus,

after a few hundred million stopping operations in |

a heavy duty track circuit finally that Molybdenum auxiliary contact fail because the corresponding Contact material has been used up · You service life of a The protective tube contact can be extended by providing a very large auxiliary contact, the probability of the molybdenum deposited on the tungsten contact 23 being transported back enlarge. The bridge of the help contact is for this purpose preferably flattened, as the Pig »5

showed I.

Apart from the fact that the molybdenum wire In the aforementioned Wisely ensures a long service life, he assures a good contact material that is ductile enough, to be brought into the desired shape ssu and auoh

9846/1584

has enough spring properties to generate the desired preload. Another part of the gate of the molybdenum wire is that it is also at temperatures of 760 ° Q and more can accommodate bending loads. Saraus follows that the auxiliary contact 12 on the Switching tongue 6 can be welded on before the switching tongue is heated for degassing and fastened to the stop tab 11 with appropriate bias. Understandably, the auxiliary contact is to be attached to the tongue 6 with a preload that is essential is greater than what you would like to have in the finished protective tube contact, as a certain proportion of the Preload is lost if the protective tube contact is heated accordingly for degassing. However, if the auxiliary contacts always have an initial Preload can be assembled «which corresponds to the yield point of the material and the tongue arrangement always is brought to a certain maximum degassing temperature of, for example, 820 ° C., the bias of the auxiliary contact with respect to the tongue 6 is at the finished protective tube contact always in direct relation to the temperature to which the protective tube contact was heated.

The foregoing description and the accompanying drawings show that the invention can also be »

operated reed switch that works very quickly and closes and opens precisely depending on rapidly changing magnetic fields of actuation, the circuits with very high sebaltic capacities switches with relatively large YA values and even with; Gtleichetromhetrleh has a long lifespan.

009846/1564

Claims (1)

.40-20163C8 Claims. / 1 ο! Magnetically "actuated protective tube contact, which in ^ - ^ its housing contains two resilient, electrically conductive switching tongues anchored at opposite ends made of magnetizable material, the free ends of which lie opposite each other at rest and are pretensioned on assigned stop rods support _P, characterized in that on one of the switching tongues (6) an auxiliary contact (12) protruding towards the other sliding tongue (β ") is attached, which with a bias in the direction of the other sliding tongue (6 ³ ) acts on it supporting switch tongue (6). 2c protective tube contact according to claim 1, characterized in that the contact-making parts (18, 13 _Ρ 23) of the Seheiteungen (6, 6 ¹ ) from the HiIJ.akontaktes ("12) consist of difficult to melt material and work in high vacuum. 3. Schutsrohrkontakt according to claim 1 and 2 _r, characterized in that the contact surfaces (18,23) of the Bshaltzungen (6, 6 ') made of tungsten and the contact surface of the Hilfekontakteβ (12) consists of molybdenum " 009846 / 156Λ ^BAD 4. Protective tube contact still claim 1 to 3 _9, characterized in that the auxiliary contact (12) is a resilient bow-shaped molybdenum wire .. is _p whose legs (19-21) bent U-shaped siMj wöbsi the bent leg ends (21) at 'the from Stop rod (11) are attached to the front side facing away from the viewpoint _p while the Schenlcelteile (19) in front of the bend (20) grip the switch tongue (6) laterally _p on the switch tongue tick side facing the stop rod (11) and rest resiliently in front of the switch tongue ( 16) a web-au = · artigenp to another Sohaltzunge (6 ^e) projecting contact surface (13) converge " Reed relay for operation ₈ during dea opening of the current always in the same direction NaOH fließtp claim 1 wherein said Ms 4 ₉ characterized in that the gekennzsichnets located at a negative potential while opening contact surface (18) consists of a feterial · whose! | The wax and evaporation points are at least as high as those of tungsten, while the one that has a positive potential when it is opened. The contact surface (13) consists of a material with deep melting and melting points, BATH ORIGINAL Ö0984B / 1S8A 6. Protective tube contact according to claim 5, characterized in that the open home contact surface (13) which is at positive potential is made of molybdenum 7. protective tube contact according to claim 1 to 6, characterized in that the switching tongues (6, 6 ') in one piece are designed to have a lower rigidity than the stop rods arranged next to them (11, 11 *) t and from a foot 11 (15) lying flat on the stop rod (11, 11 *), one on the free one End formed head part (16) and an intermediate shark part (17) exist, the one has reduced cross-section. Protective tube contact according to claim 7, characterized in that the neck part (17) has essentially the same width as the other switching tongues at Ie (15, 16), but has a smaller thickness and in the direction of the free end of the switching tongue (6, 6) ') is angled divergingly against the stop rod (11, 11') and that the head part Π6) from the neck Ll (! 7 ) ^{converges against the stop tab} (11, 11 Ί) and there in the rest position applies preload, BATH ORIGINAL / I Τ> ^Λ , 9ο protective tube contact according to claim 1 to 8, characterized in that the switching tongues (6, 6 ") are formed by at least partially magnetizable bimetal strips« whose two metals below a predetermined temperature range in which both metals can still absorb voltages, linear ones that are very similar to one another have thermal expansion coefficients, whereas above the predetermined temperature range the metals \ have different coefficients of expansion and adjacent to the metal with the greater in this area KoeffiEienten the stop bar (11 _f 11 ·) iBTC Oo protective tube contact according to claim 9, characterized in that the _{metal adjacent to the stop rod (11 s} 11 ·) is an alloy with 40.5 to 41.5 # nickel, a maximum of 0 _t 02 # carbon, a maximum of 0.255 * silicon and reed iron and that other metal is an alloy % with 28.5 to 29t5 * lfickel _f 16.5 to 17.55 * cobalt, a maximum of $ 0.5 manganese and the remainder iron. BATH ORIGINAL 00984 6/1564 Blank page