US2932703A - Miniature switch mechanism - Google Patents

Description

E. R. HABERLAND MINIATURE SWITCH MECHANISM A ril 12, 1960 Filed Aug. 26, 1957 ERNEST R. HABERLAND,

BY QM/5M AGENT United States Patent MINIATURE SWITCH MECHANISM Ernest R. Haberland, Los Angeles, Calif., assignor to Hughes Aircraft Company, Culver City, Calif., a corporation of Delaware Application August 26, 1957, Serial No. 680,098

7 Claims. (Cl. 200-87) This invention relates to switches and relates more particularly to miniature switches that are operable through disposition thereof in a magnetic field.

In low voltage dry circuit applications, i.e., arrangements employing volt or less and current in the order of a few microamperes, serious problems have heretofore existed and primarily caused by the normal formation of a layer of nonconductive metallic oxides on contact elements. Additionally, contact elements have frequently had foreign material deposited on the surfaces thereof and the presence of oxides and/or such foreign material prevents desired electrical conductivity between the contact elements. The foreign material may take the form of and be carried by various types of organic and inorganic vapors such as oil or water, as well as dust and other physical particles.

In order to operate such contacts in low voltage situations, and in order to maintain reliability in an ambient air atmosphere, several solutions to the normal problems have heretofore been used, such as creating high contact pressure whereby to crush through foreign matter or oxidation on contacts. Also, contacts have been provided with a long lever arm and structure to cause a wiping action between contacts, in order constantly to eliminate foreign material and polish 0B. any oxidation that may have formed thereon. Both of these solutions cause excessive wear of the contact material, thus requiring the use of large mass contacts and/or requiring the use of heavy springs or other mechanical devices to establish the high contact pressure necessary, thus also requiring high operating forces.

Another solution to the problems heretofore presented resides in the disposition of the contacts in a fixed atmosphere usually created by the sealing of these contacts within an enclosure. Such enclosures have been filled with an inert material such as nitrogen gas, for example. In these instances light contact pressure may be employed and no crushing or wiping action between the contacts is necessary.

When sealing contacts within an enclosure, an additional problem arises, that of providing operating means for the contacts and maintaining the operating means at a size that is commensurate with use thereof in miniaturized electrical systems and components. For this purpose, sealed elongated glass envelopes, employing two or more reeds of magnetic material, have been employed, with the reeds being movable into contact with each other by disposition thereof in a magnetic field. Reed type switches are completely satisfactory for some installational situations; however, due to the construction thereof, they cannot be used in extremely miniaturized components as may be desired in computers and the like that must be carried as airborne equipment such as in aircraft, missiles, rockets and thelike. The reed type switches must necessarily be relatively long and, when several of these switches are mounted circumferentially about an actuating magnet and severalother banks thereof are placed in end to end relationship, the resulting multiple switch structure becomes extremely large and completely incompatible with the small space envelopes available in particular installational situations. Additionally, due to the fact that reed type switches have a generally elongated configuration, the disposition of the reeds in the most advantageous position in a magnetic field, i.e., intermediate the poles of a magnet, becomes extremely difficult and, in some cases, impossible.

Accordingly, it is one object of the present invention to provide a miniature switch mechanism that may be operated and used in low voltage, low current applications.

It is another object of the invention to provide a miniature switch mechanism that may be energized by disposition in a magnetic field.

A further object of the invention is to provide a mag: netic switch mechanism employing contacts that are reliably operable with low contact pressure and no wiping action.

Still another object of the invention is to provide a miniature switch mechanism wherein contacts thereof have a relatively long life expectancy.

A still further object of the invention is to provide a magnetic switch mechanism having counterbalanced contacts disposed on free ends of resilient arms, whereby to reduce contact bounce or rebound and provide for positive action thereof.

A further object of the invention is to provide a miniature, magnetically operable switch mechanism having construction and assembly characteristics enabling efficient and economical manufacture thereof and reliable operating characteristics.

Another object of the invention is to provide miniature magnetically operable switch mechanism and an enclosure therefor. 7

Other and further important objects of the invention will become apparent from the disclosures in the following detailed specification, appended claims and accompanying-drawing, wherein:

Figure 1 is a transverse sectional view through a typical, partially schematically illustrated, multiple switch apparatus employing the switch mechanisms of the present invention;

Fig. 2 is an enlarged transverse sectional view through the present switch mechanism and showing the contacts in an open position;

Fig. 3 is a sectional view similar to Fig. 2 showing the contacts in a closed position and diagrammatically showing the operating arrangement therefor;

Fig. 4 is a transverse sectional view of the switch echanism as taken substantially as indicated by line 4 4, Fig.2;

Fig. 5 is a greatly enlarged, partially sectional view of one of the contact elements and counterbalance arrangement therefor, as taken substantially as indicated by line 5--5, Fig. 4; and

Fig. 6 is an enlarged fragmentary sectional view of one of the resilient, contact carrying arms, as taken substantially as indicated by line 66, Fig. 2.

With reference to the drawing, the miniature switc mechanism of this invention is shown as indicated generally at 10. The present switch mechanism may be of any desired size; however, it has been found to be practical, and switches have been manufactured in a minute size in the order of in diameter and A in length. The illustrations contained herein are all therefore greatly enlarged with one feature hereof residing in the particular construction enabling manufacture and use in miniaturized applications. For example, as shown .in Fig. 1, it is often desirable to employ a number of switches in an electrical sequencing or switching structure. The structure shown in Fig. 1, by way of example,

comprises a housing 11 having a rotatable shaft 12 disposed therein. A plurality of the switch mechanisms are carried by the housing 11 and extend into an inner cavity 13 thereof. As shown, the switches 10 are arranged in two banks of circumferentially spaced units; however, it is to be understood that any number of such switches may be disposed in a circumferential or other pattern and arranged in as many banks as desired without departing from the spirit and scope hereof.

The shaft 12 has a pair of permanent magnets 14 carried thereby and spaced both circumferentially and longitudinally on the shaft, each of the magnets 14 cooperating with one of the circumferential banks of switches '10. As will be later described, the poles of the magnets 14 serve to actuate contacts in the switches '10 as these poles are brought in coextensive alignment with. such contacts by rotation of the shaft 12. In this connection it is to be understood that several magnets may be employed with each bank of switches 10 and may be spaced and arranged relative to each other longitudinally or circumferentially on the shaft to meet particular sequencing or'switching requirements. Additionally, it is further to be understood that the switches 10 may be used individually rather than in groups to satisfy other operational requirements.

With reference now primarily to Figs. 2 through 6, the switch mechanism hereof comprises an annular metalside of each of the arms 25.

portions 32 have a recess 36, with the counterbalance,

The free ends of the shank members 34 being retained thereon and in contact with the ar'ms ZSby upsetting an end of the shanks as at 37 over an end 38 of each of the counterbalance members 34. Thus, a shoulder 40 on each of the contact head portions 31 is also retained in tight contact with another side of each arm 25. I

ably heat treated after plating, an outer layer 4-2 having he base member 15 having a shank portion 16 and an annular outwardly extending flange 17. The base member 15 may be made from any suitable material, is preferably nonmagnetic and has an integral annular V-shaped ridge 18 formed in an axial direction from the flange 17, for a purpose to be hereinafter more fully described.

. The base member 15 is adapted to support a pair of metallic electrical leads 20 generally within a central area of a bore 21 therethrough. The leads 20 are rigidly retained within confines of the bore 21 by means of an insulating material 22 that may be glass or the like, the

high electrical conductivity as may be derived from mate rial such as rhodium, for example. Thus, a contact structure is established wherein high electrical conductivity is maintained and peeling or chipping of the plating is minimized through the multiple layer plating technique. Additionally, when the contacts are in a closed position as shown inFig. 3, the nonmagnetic nature of the plated layers 41 and 42 serve to provide a magnetic gap between the highlyrpe'rrneable head portions 31. This magnetic gap serves to control the dropout or separation time of the contacts when removed from a magnetic field. Thus, positive contact and subsequent release as between the contact members 30 is controlled and maintained.

As shown, the contacts 30 and arms 25, as well as inner ends 23 of the leads 20, are'enclosed within a case 43 that may be made from any suitable nonmagnetic material such as, for example, silver or the like. The case 43 has an annular flange 44 adjacent an open end thereof, this flange being secured to the annular ridge 18 of the base member 15 as by projection welding, thusto create a construction being such as to provide a hermeticseal The expansion coefiicients between the erally rectangular portion 23 thereon and positioned ad- I jacent an inner surface 24 of the insulating material 22. An arm 25 is secured to each of the rectangular portions 23, at least one of these arms being of resilient material. With reference to Figs. 4 and v6, it is to be noted that lower ends of each of the arms 25 are provided with outwardly extending, portions 26 that are bent or wrapped about the rectangular portions 23 of the leads 20 and secured thereto as by means of a spot weld 27,

thus firmly to secure the arms 25 to the leads 20, provide the desired electrical connection therebetween, and maintain a rigid support for the lower ends of the arms 25. The arms 25 are made from anonmagnetic material such as, for example, beryllium copper and are sufficiently resilient as normally to maintain. the arms in a substantially parallel relationship relative to each other and as shown in Fig. 2. a Y I V The free ends of the arms 25 serve to support contact members indicated generally at 30. The contacts 30 are made from a highly permeable magnetic material such as an iron-nickel alloy and each have a head portion 31 and a reduced diameter elongated shank portion 32. The shank portions 32 are adapted for disposition in openings .33 in the free ends of each arm 25, and a counterbalance member 34, of magnetic material and in the form f of an annular ring, is disposed about each of the shank portions. Each of the counterbalance members 34 has oneend surface 35 that is disposed in contact with. one

acteristics.

hermetically sealed enclosure structure. .A space 45 within the case 43 may also be. filled with an inert material such as, for example, nitrogen gas or the like.

. In operation of the present switch mechanism, as shown diagrammatically in Fig, 3, the poles of the magnets 14 are disposed in substantially coextensive alignment with the contacts 3t). It is to be noted that the case 43 serves to establish and maintain a greater space between the. poles of the magnet 14 and one end of the contacts 30, than the normal space between the contacts 30. Thus, the magnetic field induces opposite polarity in the counterbalance members 34 and heads 31 of the contacts 30 causing the heads to be moved toward and into contact with each other. Removal of the magnetic field serves to cause separation of the contacts by the resilient action of at least one of the arms 25. It is to be noted that the construction hereof is such as to dispose an elongatedrelati'vely large mass of magnetic material, forming the contacts 34), in line withthe magnetic field disposed thereabout. This elongated structure serves to enable operation of the switch mechanism with a relatively low magnetic flux. t

It is to be noted that the counterbalance members 34 serve to dispose the center of mass of each of the contacts 30 in line with the respective resilient arms 25,

rather than at one side thereof, thus to create a continuous, pure arcuate bend of the arms 25, rather than any random bending thereof that would otherwise occur.

This counterbalancing arrangement serves to reduce, and in most instances serves to eliminate any contact bounce that would otherwise cause undesirable electrical char- This is particularly true with the application of magneticv operating forces directly to and coextensive alignment with the contact members '30, rather than through any type of level system of the type usually employed in conventional heretofore known relays. Additionally, the spring force. of at least o ne of the resilient arms 25 need only be very light to accomplish the desired results.

It may thus be seen that a reliable, 'efiicient and effectiveminiature switch mechanism has been provided that may be operated in installational situations requiring the use of aplurality of such switches arranged in a compact and miniaturized support. It may also be seen that this particular switch mechanism requires only small operating forces and may be used in low voltage applications, means being provided to eliminate c'orrosion of contact members and/or disposition of foreign materials on the contacts.

Having thus described the invention and the present embodiment thereof, it is desired to emphasize the fact that many further modifications, including more than two contact members, may be employed and resorted to in a manner limited only by a just interpretation of the following claims.

I claim:

; l. A miniature switch mechanism comprising, in combination; 'a base member; an insulating material carried by said base member; a pair of leads disposed through and retained against movement in said insulating material; flexible metallic arms carried by inner'end of said leads, said arms being disposed in spaced substantially parallel relationship; metallic electrical contacts of permeable material carried by free ends of said arms and disposed in facing spaced relationship to each other, said contacts having reduced diameter shank portions disposed through openings in said arms; counterbalance members disposed about said shank portions, an outer end of said shank portions being deformed to retain said counterbalance members thereon and in contact with said arms; and a protective case positioned in spaced relationshipabout said arms and said contacts, said case being secured to said base member, said contacts being adapted for movement into engagement with each other upon disposition thereof in a magnetic field.

2. A miniature switch mechanism comprising, in cornbination: a base member; an insulating material carried by said base member; a pair of leads disposed through and retained against movement in said insulating material; flexible metallic arms carried by inner end of .said leads, said arms being disposed in spaced substantially parallel relationship; metallic electrical contacts of permeable material carried by free ends of said arms and disposed in facing spaced relationship to each other, said contacts having reduced diameter shank portions disposed through openings in said arms; counterbalance members disposed about said shank portions, an outer end of said shank portions being deformed to retain said counterbalance members thereon and in contact with said arms; and a protective case of nonmagnetic material positioned in spaced relationship about said arms and said contacts, said case being secured to said base member, said contacts being adapted for movement into engagement with each other upon' disposition thereof in a magnetic field, said spacing between said contacts being less than said spacing between said contacts and said ease.

3. A minature switch mechanism comprising, in com-- bination: an annular base member; an annular ridge on said base member; an insulating material carried by said base member; a pair of leads disposed through and retained against movement in said insulating material; flexible metallic arms of nonmagnetic. material carried by inner end of said leads, said arms being disposed in spaced substantially parallel relationship; metallic electrical contacts of permeable material carried by free ends of said arms and disposed in facing spaced relation ship to each other, said contacts having reduced diameter shank portions disposed through openings in said arms; counterbalance members disposed about said shank portions, an outer end of said shank portions being deformed to retain said counterbalance members thereon and in contact with said arms; and a protective case of nonmagnetic material positioned'in spaced relationship about said arms and said contacts, said case being secured to said annular ridgeon said base member, said contacts being adapted for movement into engagement with each other upon disposition thereof in a magnetic field, said spacing between said contacts being less than said spacing between said contacts and said case.

4. A miniature switch mechanism comprising, in combination: a base member; an insulating material carried by said base member; a pair of leads disposed through and retained against movement in said insulating material, inner ends of said leads extending beyond said insulating material and having generally rectangular cross sections; flexible metallic arms carried by said inner end of said leads and welded thereto, said arms being disposed in spaced substantially parallel relationship; metallic electrical contacts of permeable material carried by free ends of said arms and disposed in facing spaced relationship to each other, said contacts having reduced diameter shank portions disposed through openings in said arms; counterbalance members disposed about said shank portions, an outer end of said shank portions being deformed to retain said counterbalance members thereon and in contact with said arms; and a protective case positioned in spaced relationship about said arms and said contacts, said case being secured to said base member, said contacts being adapted for movement into engagement with each other upon disposition thereof in a magnetic field.

5. A miniature switch mechanism comprising, in combination: an annular base member; an annular ridge on said base member; an insulating material carried by said base member; a pair of leads disposed through and retained against movement in said insulating material, inner ends of said leads extending beyond said insulating material and having generally rectangular cross sections; flexible metallic arms of nonmagnetic material carried by said inner end of said leads and welded thereto, said arms being disposed in spaced substantially parallel relationship; metallic electrical contacts of permeable material carried by free ends of said arms and disposed in facing spaced relationship to each other, said contacts having reduced diameter shank portions disposed through openings in said arms; counterbalance members disposed about said shank portions, an outer end of said shank portions being deformed to retain said counterbalance members thereon and in contact with said arms; and a protective case of nonmagnetic material positioned in spaced relationship about said arms and said contacts, said case being secured to said annular ridge on said base member, said contacts being adapted for movement into engagement with each other upon disposition thereof in a magnetic field, said spacing between said contacts being less than said spacing between said contacts and said case.

6. A miniature switch mechanism comprising, in combination: a base member; an insulating material carried by said base member; a pair of leads disposed through and retained against movement in said insulating ma terial; flexible metallic arms carried by inner end of said leads, said arms being disposed in spaced substantially parallel relationship; metallic electrical contacts of permeable material carried by free ends of said arms and disposed in facing spaced relationship to each other, said contacts having reduced diameter shank portions disposed through openings in said arms; multiple plated coatings of a nonmagnetic metallic material on said contacts; counterbalance members disposed about said shank portions, an outer end of said shank portions being deformed to retain said counterbalance members thereon and in contact with said arms; and a protective case positioned in spaced relationship about said arms and said contacts, said case being secured to said base member, said contacts being adapted for movement into engagement with each other upon disposition thereof in a magnetic field.

7. A miniature switch mechanism comprising, in combmatron: an annular base member; an annular ridge on said base member; an insulating material carried by said a e memb -3 Pai Q ead i pose M9148 319 tained against mpyement-jn said insulating material, inner ends of said leadsextendingbeyond said insulating material andhaving; generally rectangular cross sections;

flexible metallic arms of; nonmagnetic material carried by said inner end of saidleads and Welded thereto, said arms being disposedin spaced substantially parallel-relationship; metallic electrical contacts of permeable material carried by free ends of said arms and disposed in facing spaced relationship to each other, said contacts having reduced diameter shank portions disposed through openings in said arms; multiple plated coatings of a nonmagnetic metallic material on said contacts; counternc ember p se abou a dv hi n p rtio s, n er nd of saidsh nk or is s b ing. fOI W retain saidlcounte halance members-thereon and in cont'actwith saidarms; and-a protective case of nonrri agnetic'material positioned inspaced relationship; about said arms, and

V I said contacts, said case being; secured to' said annular ridge on said base member,saidcontactsgb inQ'adapted for movement into'engagement' with each other upon: disposition thereof in a magnetic field, said spacing be;

tween said contacts being less than,said-spacingfbetween said contacts and said case,

ReferencesCited in the file of this patent UNITED STATES PATENTS 2,265,297 Little Dec. 9, 1941 2,285,352 Paulson June '2, 1942 2,542,668 Harrison Feb. 20 1951 2,570,315 Brewer Oct. 9, 1951 FOREIGN PATENTS I 135,00 Australia Nov.,2, 1945 536,695

Great Britain 54 11 194

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