US3586809A - Reed switch for rapid cycle,high power applications - Google Patents

Reed switch for rapid cycle,high power applications Download PDF

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Publication number
US3586809A
US3586809A US818913A US3586809DA US3586809A US 3586809 A US3586809 A US 3586809A US 818913 A US818913 A US 818913A US 3586809D A US3586809D A US 3586809DA US 3586809 A US3586809 A US 3586809A
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Prior art keywords
reed
contact
switch
post
contactor
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US818913A
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English (en)
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John D Santi
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Briggs and Stratton Corp
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Briggs and Stratton Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/0201—Materials for reed contacts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/02—Contacts characterised by the material thereof
    • H01H1/04—Co-operating contacts of different material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/50—Means for increasing contact pressure, preventing vibration of contacts, holding contacts together after engagement, or biasing contacts to the open position
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H51/00—Electromagnetic relays
    • H01H51/28—Relays having both armature and contacts within a sealed casing outside which the operating coil is located, e.g. contact carried by a magnetic leaf spring or reed
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H51/00—Electromagnetic relays
    • H01H51/28—Relays having both armature and contacts within a sealed casing outside which the operating coil is located, e.g. contact carried by a magnetic leaf spring or reed
    • H01H51/287—Details of the shape of the contact springs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/30—Means for extinguishing or preventing arc between current-carrying parts
    • H01H9/38—Auxiliary contacts on to which the arc is transferred from the main contacts

Definitions

  • This invention relates to magnetically actuated reed switches and more particularly to a reed switch that is especially well suited for use in a circuit that carries substantially high power and must be opened and closed at recurrent intervals of short but variable duration.
  • Magnetically actuated reed switches have been available for many years, and have long been recognized as potentially use- 1 ful in many applications. In practice, however, such switches have heretofore had limited utility because of their inability to operate satisfactorily in high volt-ampere circuits and to respond accurately to short, rapidly recurring cycles of buildup and decay of a magnetic actuating field. For example, one such switch, recently placed on the market and considered to represent an advanced state of the art, was rated for 240 operations per minute and to break 3 amps. at 125 volts, AC, and 2 amps. at 250 volts, AC.
  • a reed switch should have a long service life as well as a high cycle speed and a high power rating.
  • the above mentioned recently marketed reed switch had an advertised life expectancy of only 500,000 operations when breaking 3 amps. at 120 volts AC. Under conditions of rapid cycling this would represent an extremely short service life, e.g. less than 40 hours at 240 0pm.
  • the present invention has as its general object to achieve a substantial advance over the state of the reed switch art represented by US. Pat. No. 3,315,193, and, specifically, to provide a reed switch that not only compares favorably in cycle speed with the switch of said patent, but in addition, has the ability to break circuits carrying on the order of 1,500 volt-amperes, and has a service life expectancy on the order of hundreds of millions of operations at its rated power.
  • the resilient flexing bias of its reed or reeds, by which its contacts are separated for switch opening should be a relatively light one; and in addition, for it to close and open in accurately timed relation to the buildup and decay of a rapidly cycling magnetic field, the normal gap between its contacts should be relatively small.
  • a switch that meets these requirements tends to have relatively light contact pressure in its closed condition, and therefore, to avoid high contact resistance, prior reed switches usually had contacts of copper or precious metal operating in an inert gas. But such contacts tend to stick and erode when handling high power, and therefore the capability for controlling substantially high power has been regarded as incompatible with the requirement of a reed switch, and particularly one intended for rapid cycling.
  • a reed for a reed switch is a tuned element which vibrates at some natural frequency and which thus tends to have different responses at different rates of cyclical buildup and decay of a magnetic actuating field, depending upon whether or not the frequency of a building magnetic field is in phase with the vibration of the reed following an immediately prior switch opening.
  • Another general object of this invention is to provide a very versatile reed switch that is adapted for very rapid cycling and is suitable for high voltage-high current applications, but which nevertheless has a relatively low resistance when closed so as to be well suited for low voltage applications where switch resistance must be kept to a minimum.
  • Another general and very important object of this invention is to provide a reed switch that has a very long service life expectancy even in high power DC applications.
  • the useful life of a switch depends upon the current that it is required to interrupt, particularly if it must always open when current is flowing in the same direction, as in a DC circuit.
  • the same switch operating in comparable AC service, will normally have a substantially longer useful'life because the switch does not always open at the peak current in the cycle and, further, because each contact is the positive one in about 50 percent of the openings of the switch so that material transferred during any one opening will be transferred back to its original site in a subsequent opening.
  • Still another specific object of this invention is to provide a reed switch having each of its reeds normally engaging a post or rebound stop under bias, so as to have a yielding preload in accordance with the teachings of the above mentioned US. Pat. No. 3,3l5,l93, and wherein the reeds can have such a preload of a predetermined value in the finished switch even though they are heated to a substantially high temperature during the course of manufacture of the switch.
  • Another specific object of this invention is to provide a reed switch for rapid cycling having refractory metal contacts that operate in a deep vacuum environment and having reeds that can be outgassed before assembly of the switch is completed without losing their preload, so that the deep vacuum environment for the contacts will be maintained during a long service life of the switch.
  • FIG. 1 is a view in side elevation of a reed switch embodying the principles of this invention with a portion of its envelope shown broken away, the switch being illustrated in its normal open condition;
  • FIG. 2 is a view similar to FIG. I but showing the switch in its closed condition
  • FIG. 3 is a disassembled perspective view of the components of the switch of this invention that are inside its envelope;
  • FIG. 4 is a view in front elevation of the reed assembly that includes the contactor
  • FIG. 5 is a side view on an enlarged scale of a reed element of the switch of this invention.
  • FIG. 6 is a graph of the relationship between temperature and linear expansion of each of three metals used in the reed of the switch of this invention.
  • FIG. 7 is a graph of the forces acting upon a reed in the switch of this invention.
  • the numeral 5 designates generally a reed switch embodying the principles of this invention, comprising a pair of elongated, resiliently flexible, magnetically permeable reeds 6 and 6' enclosed in an elongated hermetically sealed envelope 7 of glass or the like.
  • the envelope is evacuated to a deep vacuum.
  • Extending through the sealed ends of the envelope are a pair of elongated terminal members 8 and 8, one for each of the reeds 6 and 6'.
  • Each of the terminal members supports its reed at its inner end and has its outer end portion exposed to provide one of the terminals 9, 9' of the switch.
  • the reeds 6 and 6' extend axially inwardly from their respective terminal members 8 and 8, and their free tip portions are disposed in lengthwise overlapping relationship in the medial portion of the envelope, normally spaced apart laterally by a predetermined distance to define a gap 10. Under the influence of a magnetic field that threads the reeds and the gap 10, the reeds are flexed to bring their overlapping tip portions into contact with one another.
  • each terminal member 8,8 is also secured to the inner end of each terminal member 8,8 .
  • an elongated, relatively stiff post or rebound stop which ex tends lengthwise along the reed at the side of the latter that is remote from the other reed, the post for the reed 6 being designated II and the post for the reed 6 being designated 11. Since each reed is formed from flat strip material, it can be said to have a rear surface that faces its post and a front surface that faces the other reed.
  • Each reed normally engages its post under flexing bias so as to have a rearward preload against the post in accordance with the teachings of the above mentioned US. Pat. No. 3,3 I 5,193, to which reference may be made for an explanation of the advantages of this arrangement and the manner in which it affords extremely high cycle speed in a reed switch.
  • the reed 6 carries a contactor 12 which normally engages the rear surface of said reed 6 under forward flexing bias and which has a contact portion 13 that projects forwardly across the tip of the reed 6 to be normally spaced from the reed 6 by a distance somewhat smaller than that across the gap 10 between the tip portions of the reeds themselves.
  • the contactor has several functions, one of which is to prevent failure of the switch due to sticking of its contacts under high current surges.
  • the envelope 7 is preferably made of a length of glass tubing that has its opposite end portions respectively drawn down around the terminal members 8 and 8' and fused to them to hold the terminal members 8 and 8' in rigidly fixed substantially coaxial relationship with one another and to provide hermetic seals around them.
  • the terminal members have their inner ends spaced apart axially by a substantial distance, and each has a post I I, ll welded to its inner end; but it will be apparent that each terminal member could comprise an integral axially outward extension of its post.
  • the length of each post is such that its tip is near the tip of its reed.
  • the post can be of either magnetic or nonmagnetic material, but it should in any case be substantially stiffer than the reed.
  • each of the reeds 6 and 6' has a substantially flat anchor portion 15 adjacent its captive end, a substantially flat armature portion 16 that comprises its free end, and a medial neck portion 17 that has a smaller cross-sectional area than the anchor and armature portions and is bent at obtuse angles to them.
  • the neck portion is of course integral with the anchor and armature portions and connects them.
  • the anchor portion 15 of each reed flatwise overlies its adjacent post near the captive end thereof and can be secured to the post as by welding.
  • the neck portion 17 extends obliquely forwardly, away from the post and toward the reed tip.
  • the armature portion 16 is normally inclined toward the post to have its tip engaging the post under rearward flexing bias.
  • the neck portion 17 has reduced cross section area.
  • the smaller cross section area of the neck portion is obtained by reducing only its thickness, as shown, to insure that the reed has a relatively flat spring rate, that is, to have the flexing stress forces in the reed increase relatively gradually with forward displacement of the reed tip toward the other reed.
  • FIG. 7 represents the forces acting on a reed in the switch of this invention as the reed is magnetically actuated towards its switch closing position.
  • the difference between magnetic force and flexing stress at any instant is the force available to accelerate'the reed at that instant, and with a reed having a flat spring rate this difference grows rapidly as the reed moves toward the other, so that the reeds converge at an increasing acceleration.
  • Confining flexing of the reed mainly to its neck portion 17 further contributes to rapid response of the reed to a magnetic field in that only the armature portion 16 of the reed undergoes substantial movement. Since the mass of the armature portion is small as compared with that of the entire reed, the armature portion is readily accelerated by the magnetic and flexing forces that respectively act upon it in its switch closing and switch opening motions.
  • the reed would have to be quite short and would therefore be so stiff that its spring force curve would cross the magnetic force curve and therefore the reed would not move to its closed position in response to a magnetic actuating fleld.
  • each reed extends obliquely to its armature portion l6 in order to minimize contact bounce when the reed tips engage one another.
  • the tendency of the armature portion to rebound is manifested in a vibration of the armature portion transversely to its flat faces.
  • the neck portion extends obliquely to the armature portion, such vibration has a substantial component lengthwise of the neck portion.
  • the armature portion is relatively short. For these reasons, the frequency of reed vibration due to any contact rebound tends to be high, and the amplitude of such vibration tends to be small.
  • Such high frequency vibration dissipates energy rapidly, and because of its low amplitude there is little energy to dissipate. Therefore such make bounce as may occur in the reed switch of this invention poses no practical problem, even at the fast closure rates that are a concomitant of high cycle speed.
  • the front surfaces of their tip portions have tungsten coatings '18. Because of their hardness, these tungsten coatings resist mechanical wear and they prevent the reed tips from stickingtogether as a result of cold welding or mechanical friction; and because of the low current flowing between the contacts 18 as they engage and separate, due to the functioning of the contactor 12 as explained hereinafter, those contacts have no tendency to be welded together especially in view of the high melting temperature of tungsten. Because of the oxygen-free environment of the tungsten contacts 18 in the switch of this invention, they do not oxidize and therefore their contact resistance remains low during the life of the switch, instead of increasing like the resistance of contacts operating in air.
  • tungsten coating 23 that provides a contact engageable by the contact portion 13 of the auxiliary contactor 12, for reasons explained hereinafter.
  • This contact 23 can of course comprise a continuation of the tungsten coated area that forms the contact 18 at the tip of that reed. (See FIGS. 3 and 4.)
  • each of the reeds 6 and 6 be under a rearward preload of a predetermined value by reason of which it normally engages its post or rebound stop with a predetermined biasing force.
  • the reed assemblies comprising the reed 6 or 6, the post I l or 11 and the terminal member 8 or 8' are necessarily subjected to substantial heating at some time during manufacture of the switch. A certain amount of heating of the reed assemblies is inevitable when the end portions of the envelope are melted and fused to the terminal members 8 and 8; and in fact heating of the reed assemblies is desirable in order to outgas them and insure that they will not emit gases that would destroy the deep vacuum in the envelope.
  • a bimetallic reed can be caused to have a desired preload after heating, and I have discovered two metals which possess properties that complement one another in a remarkable manner and cooperate to afford an extremely desirable bimetallic reed.
  • One of these metals sold under the trade names Therlo, Kovar and Rodar" (and hereinafter referred to as Kovar") consists of:
  • Niromet 42 iron balance
  • Niromet 42 iron balance
  • FIG. 6 is a graph of the linear expansion with increasing temperature of these two alloys and of tungsten.
  • the two alloys just described have very nearly equal coefficients of linear thermal expansion, so that a bimetallic reed that is made of them will not change its preload even under the most extreme changes of ambient temperature in which a reed switch could be expected to operate. Furthermore, within that temperature range the rate of expansion of these alloys is very nearly the same as that of tungsten, so that a bimetallic reed of these alloys can be very satisfactorily provided with the tungsten coating 18 on its tip portion without any danger that the tungsten coating will cause flexing of the armature portion of the reed under temperature swings by which the preload of the reed would be changed.
  • the curves of expansion vs. temperature for these two alloys are substantially linear in the temperature range just mentioned.
  • the curve of expansion of Niromet 42" per degree rise in temperature turns upward and at values above about 700 F. it again becomes linear, but at a steeper inclination than below 600 F.
  • the corresponding curve for Kovar continues upwardly in a substantially straight line to about 750 and then gradually steepens until from about 850 upwardly it again becomes linear and is parallel to the curve of Niromet 42 for temperatures about 700.
  • a bimetallic reed is made by bonding together elements of Niromet 42 and Kovar and then rolling the bimetal billet to the desired thickness to form a strip from which the reeds are made.
  • Each reed is secured to its post with the "Niromet 42" next to the post and with the reed initially under a substantially higher preload than is desired for it in the finished switch.
  • This reed assembly is then heated to a temperature substantially in excess of 800 F., and preferably on the order of 1,400" F. or above.
  • the maximum temperature to which the reed assembly is heated is not critical, so long as the reed becomes hot enough to be incapable of supporting stresses. Nor is there any criticality in the time during which the reed is maintained at the maximum temperature. Preferably, however, such heating is performed in a deep vacuum and the reed assembly is brought to a high enough temperature and held there for a long enough time to outgas it.
  • the Niromet 42 at the rear of the reed expands more rapidly than the "Kovar," and consequently a portion of the initial preload of the reed against the post is relieved. With further increase in temperature to the maximum, the reed is completely stress relieved, remaining in contact with the post but without exerting any biasing force against it.
  • the reed As the reed is cooled from its maximum temperature down to about 800", no stresses appear in it, since the two metals of which it is made are contracting at the same rate. At 800 and below, the reed is capable of supporting substantially high stresses. As it cools through the range of 800 to 600', the Niromet 42 contracts more rapidly than the Kovar and the reed is bimetallically flexed into engagement with its post under a biasing force that can be accurately predetermined on the basis of the relative thicknesses of the two alloys comprising the bimetal. Since the two metals expand and contract at substantially equal rates at temperatures of 600 and below, this biasing force or preload remains constant at all temperatures from about 600 down to room temperature.
  • the reed must be initially assembled to its post with a substantially excessive preload, so that the tip of the reed will not move forwardly out of contact with its post under the bimetallic flexing that occurs as the reed is heated through the 600-800 range. if the reed tip were permitted to move away from the post during heating, due to an insufficient initial preload, the final preload on the reed would be indeterminate because it would depend in part upon the unknown spacing between the reed tip and the post at temperatures above about 800. lf high enough, the value of the initial preload is not critical, since the final preload on the reed is purely a function of its bimetallic flexing.
  • bimetal reeds according to this invention can be made of other pairs of metals than "Kovar" and Niromet 42."
  • at least one of the metals comprising the reed must be magnetically permeable; the rates of linear thermal expansion of the two metals must be substantially similar up to a certain value, which value is within the range of temperatures at which both metals will support stress; and the rates of thermal expansion of the two metals must be different through a range of temperatures above that value, the metal having the higher rate of linear expansion in said range being at the side of the reed adjacent the post.
  • a fairly satisfactory reed according to the invention has been made of Niromet 42 having a tungsten coating along its entire length at its side remote from the post,
  • the tungsten coating serving as the bimetal element having the lower rate of linear thermal expansion in the high temperature range.
  • the contactor should be light in weight so that it does not greatly increase the mass of the reed 6 by which it is carried, and it must be substantially resilient. These requirements are nicely met by molybdenum wire, which also possesses other very important advantages that are discussed hereinafter.
  • the molybdenum wire contactor 12 is bent generally to an elongated U that has its legs 19 curved inwardly back upon themselves near their free end portions, around loops 20, to provide coplanar anchoring elements 21 that comprise the end portions of the length of wire. These anchoring elements flatwise overlie the front face of the armature portion 16 of the reed 6 and they are welded or otherwise bonded thereto.
  • the anchoring elements 21 and loops 20 lie in a plane that is spaced forwardly from the plane of the remainder of the legs 19, and the portions of said legs that lie between the bends 22 and the bight portion 27 of the contactor define a spring arm which overlies the rear face of the armature portion 16 of the reed and which normally engages the armature portion under forward bias.
  • the legs 19 of the contactor are spaced apart a distance substantially less than the width of the reed, but they diverge substantially toward the neck portion 17 of the reed and are spaced laterally from the side edges thereof.
  • the bight portion of the contactor which lies outwardly of the tip of the reed 6 and which comprises the contact 13 thereof, is bent at right angles to its spring arm portion to pro ject forwardly across the tip of said reed and beyond the front surface thereof so that with the switch in its normally open position the distance between the contact 13 and the reed 6' is less than that between the reeds themselves.
  • the contact 13 on the contactor 12 engages the contact 23 on the reed 6' before the contacts 18 on the reeds themselves come into engagement. Because of the forward preload of the contactor against the reed 6, the force required to bring the reeds into contact with one another increases markedly when the contactor engages the reed 6'. In other words, once the contactor 12 engages the reed 6, the magnetic attraction force acting on each reed is yieldingly resisted by the flexing force of the reed itself combined with that of the contactor 12. in H0.
  • the contacts on the two reeds comprising the tungsten coatings 18, provide a second current path through the switch, cooperating with the contacts 13 and 23 on the contactor and the reed 6, respectively, to provide the switch of this invention with a relatively low net resistance whereby it is well suited for low voltage applications as well as for high power circuits.
  • contactor l2 While the contactor l2 performs very important functions in preventing make bounce" and in maintaining low net resistance through the closed switch, its role during switch opening is perhaps even more important.
  • the reeds in the switch of this invention have a very flat and relatively low spring rate so that they respond promptly and consistently to a rapidly building magnetic field. But sticking is always a problem with switch contacts that must open a high power circuit, even with high melting contacts operating in a deep vacuum; hence reeds of low stiffness could not, by themselves, exert sufficient contact separating force to interrupt a circuit carrying high power. In the switch of the present invention, contact sticking from all causes is overcome by means of the contactor 12.
  • the contactor enables the reed switch of this invention to interrupt as high as 3,000 volts at 0.5 amp., with surge voltages at break that are as high as about 15,000 volts.
  • the current that a switch is required to break normally determines its service life expectancy.
  • the switch of this invention has been found to have a substantially longer useful life than prior reed switches even when breaking currents of as high as amperes. At 0.5 amperes DC a switch of this invention has been found to be still useable after more than 200 mil lion operations; and with lower currents its useful life would increase in a nearly linear inverse relationship to current.
  • the contact 13 is an integral part of the contactor 12, which is made of a single piece of molybdenum wire, and it cooperates with a tungsten contact 23 on the reed 6'.
  • the contacts 13 and 23 were both of tungsten, operating in a deep vacuum, they would open without sparking or arcing, but a certain amount of tungsten would transfer from the positive contact to the negative one at each switch opening.
  • This transfer of material to the negative contact is the well known low voltage phenomenon that occurs in arcless, sparkless separation of any switch contacts through which current is flowing. The reason for it is fairly well established.
  • contact pressure goes to zero, the contacts are engaging each other at an infinitesimal point through which all of the current in the circuit must flow, and the energy thus charged into the contact metal in this very localized area heats it above its melting point, however high this may be.
  • the molten particle of metal thus formed is for a brief instant held in place by surface tension, bridging the separating contacts, but as the contacts continue to move apart its surface tension collapses and it settles back onto the contacts. However, most of the molten metal settles onto the negative contact, because the positive contact becomes hotter than the negative one. While the amount of metal thus transferred at each opening is relatively small, it varies in more or less direct proportion to the amount of current carried by the switch.
  • the tungsten does not take part in the transfer and retransfer described above, because its melting and vaporizing temperatures are substantially higher than those of molybdenum and because in the very first phase of contact separation, when arcless transfer is occurring, the tungsten contact is the one to which such material transfer always takes place, so that molten molybdenum is being deposited onto it.
  • the temperature of the cathode spot is determined by the characteristics of molybdenum; or in other words there is not enough power to support ionization of the tungsten once the molybdenum is vaporized off of it.
  • the long useful life of the switch of this invention is due to the spread or difference between the melting and vaporizing temperatures of the two metals comprising the respective contacts 13 and 23 and the deep vacuum environment in which they operate.
  • Contacts of other materials could be used in a switch embodying the principles of this invention provided that the material of the negative contact was one that did not produce an effective cathode spot within the power levels for which the switch was intended, and that the material of the positive contact did so; and provided, of course, that such contacts were in a deep vacuum.
  • tungsten and molybdenum are the preferred metals because both of them melt at high enough temperatures to obviate the possibility of the contacts being welded shut, and both are hard enough to resist mechanical wear that might in time produce frictional sticking.
  • the switch of this invention will not last forever.
  • a certain amount of the molybdenum that is vaporized at each switch opening is dissipated to the wall of the envelope 7, and not all of the molybdenum that is transferred to the tungsten contact 23 will be reengaged by the contactor 12.
  • the molybdenum that is deposited in locations where it is never again contacted by the molybdenum contact cannot take part in cathode spot vaporization and therefore cannot be transferred back to the molybednum contact member.
  • the molybdenum contactor will fail because of such dissipation of the material of its contact portion.
  • the contactor it is possible to prolong the life of the switch by providing the contactor with a contact surface of substantial area, to afford the greatest possible opportunity for transfer back to it of molybdenum deposited on the tungsten contact 23.
  • the wire ofthe bight portion of the contactor is preferably flattened as shown in FIG. 6.
  • molybdenum wire makes a good contactor because it is duetile enough to be readily formed to the desired shape and has sufficient resiliency to provide the desired biasing force.
  • a further advantage of molybdenum wire is that it continues to support bending stresses at temperatures as high as l,400 F. and above. This means that the contactor 12 can be bonded to the reed 6 before that reed is heated to outgas it and fix its preload against its post ll.
  • the contactor should be fastened to the reed 6 with a preload substantially higher than that which it is intended to have in the finished switch, since a certain amount of stress relieving of the contactor will occur as it is heated during outgassing of the reed assembly.
  • the preload of the contactor against the reed 6 will always have a value, in the completed switch, that is directly related to the temperature to which it was heated.
  • this invention provides a magnetically operated reed switch that is capable of closing and opening in very fast and faithful response to the rapid buildup and decay of a magnetic actuating field; and that the switch of this invention is capable of controlling substantially high volt-ampere circuits in rapid cycling, with an extremely long service life even in DC applications.
  • a switch having a pair of contact carriers arranged for relative movement to and from engagement with one another under the influence of a magnetic field and biased to normal relative positions in which they are spaced a predetermined distance apart, said switch being characterized by:
  • said contactor having a biasing preload against said one contact carrier in the direction toward said other contact carrier;
  • said fourth contact being of tungsten.
  • a switch comprising a pair of contacts at least one of which is movable toward and from engagement with the other, for repeatedly opening and closing a circuit in which an electric current always flows in the same direction at the time of separation of said contacts so that at such times a first one of said contacts is always connected with the negative terminal of the source of current for the circuit and the other with its positive terminal, said switch being characterized by:
  • A. means defining an evacuated hermetically sealed enclosure enclosing the contacts by which they are maintained in a deep vacuum environment;
  • said first contact being of material having melting and vaporizing temperatures at least about as high as those of tungsten;
  • a reed assembly for a reed switch comprising an elongated, resiliently flexible reed having a free end and an anchored end, and means defining a stop against which the free end portion of the reed is normally engaged under bias, said reed assembly being characterized by:
  • the reed being a bimetal comprising a pair of elements which are bonded together along the length of the reed, 1. one ofsaid elements being magnetically permeable, 2. the rates of linear thermal expansion of said elements being a. substantially similar at temperatures below a value which is within the range of temperatures at which both elements will sustain stress, and
  • stop comprises an elongated post, substantially stiffer than the reed, arranged in side-by-side relation with the reed, further characterized by said reed having:
  • the neck portion of the reed being of lesser thickness than the anchor and armature portions
  • said neck portion being oblique to the anchor and armature portions of the reed and being inclined away from the post and toward the armature portion;
  • a contactor secured to the armature portion of the reed and having a spring arm overlying and preloaded against the surface of the armature portion that is adjacent to the post, said spring arm extending lengthwise beyond the tip of the armature portion and having a contact portion that projects away from the post across the tip of the armature portion to normally extend beyond the plane of the surface of the armature portion that is remote from the post.
  • a contactor secured to the reed and having l.
  • a spring arm portion overlying said free end portion of the reed and preloaded against the same in the direction away from the stop, said spring arm extending lengthwise beyond the free end of the reed, and
  • a switch of the type comprising an envelope enclosing a pair of magnetically permeable contact carriers, one of which comprises an elongated, resiliently flexible reed that is normally spaced a predetermined distance from the other contact carrier to define a gap but is flexible into engagement with the other contact carrier under the influence of a magnetic field threading the contact carriers and the gap, said switch being characterized by:
  • the envelope being I. hermetically sealed and 2. evacuated to a deep vacuum;
  • said contactor having a portion which normally projects partway across the gap toward said other contact carrier;
  • the switch of claim 12 further characterized by:
  • each contact carrier that engages the other, to provide an additional pair of cooperating contacts.
  • a contactor carried by the reed and comprising a single length of resiliently flexible wire, the medial portion of which is bent to a U-shape, with legs and a bight portion, and each end portion of which is connected with one of said legs around a loop and extends back along its leg towards the bight portion,
  • said reed having 1. a substantially flat anchor portion adjacent its anchored end,
  • the magnetically actuated switch of claim 16 further characterized by:
  • said reed being a bimetal comprising l.Niromet 42" adjacent to the post, and
  • the neck portion of the reed having a width not substantially less than that of the anchor and armature portions but having a lesser thickness than the anchor and armature portions.
  • a magnetically actuated switch of the type comprising a pair of elongated, resiliently flexible, magnetically permeable reeds, each having an anchored end and a free end, and means securing the anchored ends of the reeds at locations remote from one another and disposing the reeds with their free end portion in overlapping but laterally spaced apart relationship to define a gap between them, said switch being characterized by:
  • each of said posts being substantially stiffer than its reed and extending lengthwise along its reed at the side thereof remote from the other reed;
  • a contactor secured to one of the reeds and having 1. a spring arm portion overlying and preloaded against the surface of said reed that is adjacent to its post, said spring arm extending lengthwise beyond the free end of said reed, and
  • said neck portion of the reed being at a substantial oblique angle to the anchor portion so as to be inclined lengthwise in one direction thereto;
  • said armature portion being at an opposite oblique angle to the neck portion so as to be inclined lengthwise in the opposite direction to the neck and anchor portions.
  • said reed being a bimetal comprising 1. Niromet 42 adjacent to the post, and 2. "Kovar.”
  • a magnetically actuated switch of the type comprising an elongated, resiliently flexible, magnetically permeable reed having an anchored end and a free end, a contact engageable by the free end of the reed, and means securing the anchored end of the reed at a location spaced from the contact and disposing the reed with its free end swingable toward and from engagement with the contact and normally spaced therefrom to define a gap, said switch being characterized by:
  • a switching comprising a pair of contacts at least one of which is movable toward and from engagement with the other, for repeatedly opening and closing a circuit in which an electric current always flows in the same direction at the time of separation, said switch being characterized by:
  • A. means defining an evacuated hermetically sealed enclosure enclosing the contacts by which they are maintained in a deep vacuum environment;
  • one of said contacts being of material having melting and vaporizing temperatures at least about as high as those of tungsten;
  • the other of said contacts being of a material having lower melting and vaporizing temperatures than the material of said one contact;

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Switches That Are Operated By Magnetic Or Electric Fields (AREA)
  • Electromagnets (AREA)
  • Push-Button Switches (AREA)
  • Thermally Actuated Switches (AREA)
  • Magnetic Treatment Devices (AREA)
US818913A 1969-04-24 1969-04-24 Reed switch for rapid cycle,high power applications Expired - Lifetime US3586809A (en)

Applications Claiming Priority (15)

Application Number Priority Date Filing Date Title
US81891369A 1969-04-24 1969-04-24
AU11019/70A AU436528B2 (en) 1969-04-24 1970-02-04 Reed switch for rapid cycle, highpower applications
GB887970 1970-02-24
GB4021772 1970-02-24
GB4021972 1970-02-24
GB4021672 1970-02-24
DE2065919A DE2065919C3 (de) 1969-04-24 1970-04-06 Magnetisch betätigter Schalter mit mindestens einer federnden kontakttragenden Schaltzunge, neben welchem ein Anschlag angeordnet ist
DE2065920A DE2065920C3 (de) 1969-04-24 1970-04-06 Magnetisch betätigter elektrischer Schalter mit mindestens einer flexiblen, magnetisch permeablen Schaltzunge
DE2065917A DE2065917C3 (de) 1969-04-24 1970-04-06 Elektrischer Schalter mit Kontakten, in denen der Strom bei Kontaktöffnung stets in gleicher Richtung fließt
DE2065918A DE2065918C3 (de) 1969-04-24 1970-04-06 Schaltzunge für elektromagnetisch betätigte Kontaktanordnungen
DE19702016308 DE2016308A1 (de) 1969-04-24 1970-04-06 Magnetisch betätigter Schutzrohrkontakt
AU60435/73A AU467146B2 (en) 1969-04-24 1973-09-18 Reed switch for rapid cycle, high power applications
AU60437/73A AU461103B2 (en) 1969-04-24 1973-09-18 Reed switch for rapid cycle, highpower applications
AU60434/73A AU6043473A (en) 1969-04-24 1973-09-18 Reed switz for rapid cycle, high power applications
AU60436/73A AU6043673A (en) 1969-04-24 1973-09-18 Reed switch for rapid cycle, high power applications

Publications (1)

Publication Number Publication Date
US3586809A true US3586809A (en) 1971-06-22

Family

ID=27585123

Family Applications (1)

Application Number Title Priority Date Filing Date
US818913A Expired - Lifetime US3586809A (en) 1969-04-24 1969-04-24 Reed switch for rapid cycle,high power applications

Country Status (6)

Country Link
US (1) US3586809A (fi)
JP (1) JPS4922616B1 (fi)
AU (4) AU436528B2 (fi)
BE (1) BE749158A (fi)
CH (1) CH502686A (fi)
GB (4) GB1305586A (fi)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4011533A (en) * 1976-01-14 1977-03-08 Briggs & Stratton Corporation Magnetically actuated switch for precise rapid cycle operation
US4063203A (en) * 1975-04-15 1977-12-13 Kabushiki Kaisha Yaskawa Denki Seisakusho Reed switch
US5909163A (en) * 1996-09-11 1999-06-01 Hermetic Switch, Inc. High voltage reed switch
US20040155737A1 (en) * 2002-12-18 2004-08-12 Fujitsu Limited Electrical contacting device and method of making the same
US20090237188A1 (en) * 2008-03-20 2009-09-24 Christenson Todd R Integrated Reed Switch
US20100082268A1 (en) * 2008-09-26 2010-04-01 Peter Fischer Method and apparatus for monitoring a switching process and relay module
US20100171577A1 (en) * 2008-03-20 2010-07-08 Todd Richard Christenson Integrated Microminiature Relay
US20120235774A1 (en) * 2011-03-16 2012-09-20 Kabushiki Kaisha Yaskawa Denki Reed switch
GB2511569A (en) * 2013-03-08 2014-09-10 Christopher John Stanton Improved switch and associated methods
US20190066949A1 (en) * 2015-03-25 2019-02-28 Deqiang Jing Heavy current reed switch contact structure
US11309140B2 (en) * 2019-01-04 2022-04-19 Littelfuse, Inc. Contact switch coating

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2502388A1 (fr) * 1981-03-20 1982-09-24 Socapex Interrupteur muni de supports de contacts plats et relais utilisant un tel interrupteur
SU1720601A1 (ru) * 1988-05-05 1992-03-23 Латвийская сельскохозяйственная академия Устройство дл определени индекса продуктивности и нормы корма животных
US8431842B2 (en) * 2011-01-06 2013-04-30 Tai-Her Yang Sequential switching device with surrounding distinctive joint points structure
CN103578870A (zh) * 2013-10-30 2014-02-12 桂林机床电器有限公司 接触器触头
CN111816509A (zh) * 2019-04-12 2020-10-23 贵州振华群英电器有限公司（国营第八九一厂） 一种高压直流接触器的陶瓷基座及其组装方法

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4063203A (en) * 1975-04-15 1977-12-13 Kabushiki Kaisha Yaskawa Denki Seisakusho Reed switch
US4011533A (en) * 1976-01-14 1977-03-08 Briggs & Stratton Corporation Magnetically actuated switch for precise rapid cycle operation
US5909163A (en) * 1996-09-11 1999-06-01 Hermetic Switch, Inc. High voltage reed switch
US20040155737A1 (en) * 2002-12-18 2004-08-12 Fujitsu Limited Electrical contacting device and method of making the same
US7053739B2 (en) * 2002-12-18 2006-05-30 Fujitsu Limited Electrical contacting device and method of making the same
US20130063233A1 (en) * 2008-03-20 2013-03-14 Todd Richard Christenson Integrated Reed Switch
US8665041B2 (en) 2008-03-20 2014-03-04 Ht Microanalytical, Inc. Integrated microminiature relay
US20100171577A1 (en) * 2008-03-20 2010-07-08 Todd Richard Christenson Integrated Microminiature Relay
US8327527B2 (en) * 2008-03-20 2012-12-11 Ht Microanalytical, Inc. Integrated reed switch
US20090237188A1 (en) * 2008-03-20 2009-09-24 Christenson Todd R Integrated Reed Switch
US20100082268A1 (en) * 2008-09-26 2010-04-01 Peter Fischer Method and apparatus for monitoring a switching process and relay module
US8760246B2 (en) * 2011-03-16 2014-06-24 Kabushiki Kaisha Yaskawa Denki Reed switch
US8659375B2 (en) * 2011-03-16 2014-02-25 Kabushiki Kaisha Yaskawa Denki Reed switch
US20140049346A1 (en) * 2011-03-16 2014-02-20 Kabushiki Kaisha Yaskawa Denki Reed switch
US20120235774A1 (en) * 2011-03-16 2012-09-20 Kabushiki Kaisha Yaskawa Denki Reed switch
GB2511569A (en) * 2013-03-08 2014-09-10 Christopher John Stanton Improved switch and associated methods
GB2511569B (en) * 2013-03-08 2015-05-06 Christopher John Stanton Improved switch and associated methods
US9761382B2 (en) 2013-03-08 2017-09-12 Rel Developments Limited Switch and associated methods
US20190066949A1 (en) * 2015-03-25 2019-02-28 Deqiang Jing Heavy current reed switch contact structure
US10566157B2 (en) * 2015-03-25 2020-02-18 Deqiang Jing Heavy current reed switch contact structure
US11309140B2 (en) * 2019-01-04 2022-04-19 Littelfuse, Inc. Contact switch coating
US20220122784A1 (en) * 2019-01-04 2022-04-21 Littelfuse, Inc. Contact switch coating

Also Published As

Publication number Publication date
BE749158A (fr) 1970-10-01
GB1305587A (fi) 1973-02-07
GB1305588A (fi) 1973-02-07
AU6043473A (en) 1973-12-06
GB1305590A (fi) 1973-02-07
AU465413B2 (fi) 1975-09-11
AU6043773A (en) 1973-12-06
AU1101970A (en) 1971-08-05
AU6043673A (en) 1975-03-20
CH502686A (de) 1971-01-31
AU461103B2 (en) 1975-05-15
JPS4922616B1 (fi) 1974-06-10
AU436528B2 (en) 1973-06-05
AU465452B2 (fi) 1975-09-11
GB1305586A (fi) 1973-02-07

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