US2284644A - Electric switch - Google Patents

Description

June 2, 1942. w. DUBILIER 2,234,644

ELECTRIC SWITCH Filed Jan. 19, 1939 3 Sheets-Sheet l VIIIIIIIIII, I lllllllllll'llllllllllmll My INVENTOR. 93: Wmimm fiubili 8F L J; BY

a v zwzdww ubw ATTORNEYS June 2, 1942. w. DUBILIER ELECTRIC SWITCH Filed Jan. 19, 1959 3 Sheets-Sheet 2 VIIIIIIII/IIIIII/ lIlllllllllllllllllllllllllllllllllllhfi INVENTOR.

ATTORNEYS June 2, 1942. w. DUBILIER ELECTRIC SWITCH 3 Sheets-Sheet 3 Filed Jan. 19, 1939 IN VENTOR.

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w M w 7H ATTORNEWS Patented June 2, 1942' UNITED STATES PATENT OFFlCE 2,284,844 I mfitiffififi N.

Application January is, I939, Serial No. 251,748.

, v '2 Claims. This invention relates to electrical switches and more particularly relates to novel switch arrangements for switching electrical currents. This invention relates to improvements of the I general type of switch such as is for example disclosed in Patent No. 1,780,758. These switches interrupt substantially large currents upon relatively minute physical application of pressure or force and displacement. The switch actuating -element of a switch 01' this type consists essentially of a spring which is tensioned or biased to give a material displacement of one section thereof upon a relatively small movement of a diiierent section thereof.

In acmrdance with my present invention, I contemplate novel improvements in such switching devices for materially reducing arcing upon circuit interruption by the switch. Such arrangements permit a greater current interrupting rating for the switch as compared to the ries make-and-break switch is also useful for more complex circuit arrangements than the prior switchesof this class.

To further increase the current carrying capacity or rating of the switch, I provide novel heat conducting members specifically in the form of ventilating fins as part of or adjacent the current carrying members of the switch as will be hereinafter described. In another form, a sparkextinguishing magnet is incorporated adjacent the arcing contacts.

In accordance with the present invention 1 also provide a switch of very simplified form which is inexpensive and rugged and may be manuiacturcd with extremely small dimensions. In still another form I utilize the compact switch .as a telegraph. hey which may he carried in the palm of ones hand readily carried about on ones person. Very small pressures on the hey are translated into forces through the switch to actuate larger current interrupting members.

It is acccr ly among the objects of the present ilflftil '1 to provide novel electrical switching rr -gements having relatively large current "sting characteristics; which terially resist rein corrosion the can tacts, with im roved cooling adjacent thereto; and a particular form which is extremely small maize and inexpensive to construct.

A further object of the invention is to provide a-novel compact telegraph key operable with small displacements. v

These and further objects of the present invention will become apparent in the following description taken in connection with the drawings, in which:

Figure 1 is a perspective, illustrationof the exterior of a switch according to the present Figure 4 is a vertical cross-sectional view I through the switch taken along the line 44 of Figure 2.

Figure 5 is a bottom view of the above switch. Figures 6, 6A and 6B are modified arrangements for the armature contacting member corresponding to the form 01' Figure 3.

Figure 7 is a schematic electrical diagram oi a general circuit arrangement for the multicontact switch. v

Figure 8 is a longitudinal sectional view through a modified form of the switch arranged for materially increasing its current interruptins pr p y.

Figures 9 and 10 respectively are vertical cross-sectional views taken along lines 9-4 and ifl-IO of Figure 8.

Figure '11 is a perspective view of a modification of the invention in the form of a telegraph key.

Figure 12 is a fragmentary perspective view of a further form oi the invention for increasing the current carrying capacity of the switch contacts by heat dissipation.

Figures 18 and show another form of the invention for increasing the current carrying capacity of the member conduction.

Figure is a View,

.in perspective in Figure 1.

Figure 21 is a telegraph key device constructed with the compact switch of Figure 16.

Figure 22 is a perspective view of afurther form of the invention sealed for minimizing sparking.

Figure 23 is a cross-sectional view takenalong 23-23 of Figure 22.

Figure 24 is an enlarged perspective view of a portion of the springarmature of Figure 23.

Referring now to the figures, one form of the compact high ,current capacity switch is shown The switch is encased in a composition housing. The switch proper is set into the enclosure 26 with a removable cover 2| to complete the housing. A screw 22 is arranged to maintain the'cover 2| closed upon the housing 26. A push-button 23 projects above cover plate 2| and is adapted to actuate the spring member inside the switch housing as will be described.

The interior of the switch is shown in crosssection in Figure 2. Screw 22 has a nut 24 to keep cover 2| and housing 26 together. Posts 25 are molded within the composition housing 26 as inserts and carry one end of switch actuating member 26 by screws 21 threaded into the posts 25. The switch actuating member 26 is of the type disclosed in the Patent 1,786,758 hereinabove referred to and essentially comprises a spring member split longitudinally to form two legs 36 and slightly bowed together and secured at the free end by a movable contact 3| as shown in Figure 3. Other equivalent switch arm forms may be used.

A central hole 32 is made in member 26 in order that screw 22 may clear it. The free ends of legs 36 are slightly constricted by the attached movable contact 3| to form a bowed region at 33 of member 26. Region 33 is tensioned and otherwise biased due to the lateral constrictions of legs 36 in the manner described in the patent. When area 33 of member 26 is slightly depressed by push button 23, the normally downwardly extending free end 3| of the member is impelled upwards against effective stop 34. A slight displacement of push button 23 will cause a relatively large physical displacement of movable contact 3|.

In accordance with the present invention I provide a plurality of series-break contacts cooperating with contacts 3|. The contacts are arranged to extend from posts 35 and 36. Posts 35 and 36 are inserts molded in position in the composition housing 26 which may be Bakelite or the like. Electrical connections are made to posts 35 and 36 through appropriate lugs 31 and 36' as seen in the bottom view, Figure 5. One set of series-break contacts are mounted on lower posts 35 and are indicated at 46, 46. The upper series-break contacts are indicated at 34, 34

' mounted from the top of posts 36.

An important feature or the multi-contact series-break switch arrangement resides in the provision for insuring uniform contacting of the A plurality of contacts when engaged. Each of the contacts 34 is supported from posts 36 by reentrant spring members 38-, as shown in Figures 2 and 3. Lower contact arms 46, 46 are similarly suspended from posts 35 by reentrant spring before it reaches its dead center position as already explained.

The contact areas of elements 3|, 34 and 46 are preferably silver clad to resist corrosion. The base of'tliese members maybe copper or of other suitable material. The upper contacts 34, 34 are arranged at a position to properly arrest movable contact 3| in its upward excursion. The free'end 3| of member 26 isprevented from reaching or passing its dead center position when button 23 is depressed, by means of the effective stop contacts 34, 34 and correspond to the position of the stop member |.2 shown in the patent referred to. A spring 28 is arranged beneath spring actuating member 26 adjacent the sensitive area 33 thereof as shown in Figure 2. A set screw 29 is threaded in the base of housing 24 and is arranged for adjusting the pressure of spring 23 against member '26. This adjustment serves to properly bias the bowed member 26 into its normal contacting position against the lower contacts 46,46 as shown in the diagram.

Movable contact 3| normally presses'against the lower contacts 46, 46 and establishes a series electrical connection therebetween. When butor phosphor bronze to provide springiness and.

electrical conductivity. Electrical connection to member 26 including movable contact 3| is effective through one of the supporting metallic posts 25 at the bottom of which is secured a connecting lug 4|. The base 42 of the switch contains projections 43 and 44 molded therein to serve as feet for the unit, so that it may be placed upon a base without interfering with the elec trical connections thereto. 7

Figure 6 shows a modified arrangement for insuring proper contact between the movable contact element and the multi-conlacts. Member 26a corresponds to member 26 in the previous form and movable contact bar 3|a to corresponding bar 3| which bows together the respective legs 36a of the member. The contact bars 38 supported on the top of contact posts 36 in this form may be substantially rigid members in place of the spring supported contacts 34 of the previously described form. The legs 36a extend beyondthe clamping bar 3|a to form projecting contact portions 39, 39. Projections 39 are springy and adjust themselves for suitable pressure contactagainst the more rigid contact bars 36a. Suitable non-corrosive coatings are applied onto the contacting portions of projections 33 and bars 38a. The inherent springiness of the projections insures proper electrical connection between members 26a and the connections to post 36, 36. I

Figures 6a and 6b are modified arrangements gion al.- J

the invention to prcvide double- .ihe spring member tic has two n insulation 1 st to form ti sensitive at .i mber i125 er 2% hereinahove referred mentions and utilises in co to erm the spring relation sheet combs bowing the struco e at in a biased, a "lattice re not": its thereon. the form sensitive region or spring n ed from the springing oi an insulation layer not which may e Eahelie, mice. or other suitabie material. At the left end of legs Mu, movable contact lugs Mt: are provided to coact with contact posts for electrical connection.

Terminal connections it? are made to spring leafs M0 for conducting current, therethro'ugh. It is to be understood that the double-pole spring members of Figures 6a and 6b are mounted withmernber is so in a switch unit such as illustrated in connection with Figures L6, coacting with fixed contact posts for either single-throw or double-throw acstructed of a spring material which maintains its springy qualities at elevated temperatures. Thus, while the material for the spring member for normal temperature operation may be rectangles may be any etc 'tion as will be understood by those skilled in the sheet copper, phosphor bronze, beryllium copper or the like; for uses where a much higher temperature than normal is encountered, I employ ample as the material for the switching member I28 in Figure Go, as a hat spring instead of a wire 1' achieve this new result. The spring member I26 is mechanically constructed as heretofore with the slotted portion and bowed region as described. I prefer to employ the composition bow.- ing movable contact carrying member as shown in the modification of Figure 6a to avoid passage of the electrical current through the spring memher which, with the "Tophet C" metal, is of high resistance Electrical connections are made to the contacts supported by the composition member.

The schematic electrical arrangement empioying the multi-contact switch disclosed connection with Figures 1 to it is shown illustrative in one of a number of methods of uses Figure i when movable contact 35 n the lower position, shorting series con circuit ii. is energized completing i ca l circuitthrough lower ciemcnt or translating device iii or its equivalent from. battery or source of energy #33; At the same time, formed by the movable contact me... is completed to energize generator as in circuit ture 3! is actuated to A and D are broken and c Q, and C are com pleted. Circuit B includes iced element is and source of energy 55 in c nit across contacts 38c and it. Circuit C n load device or, generator or alternator contact Sta, and ormature 35. Figure '3- ha; included to'iliustrate general circuit peas ee of the contact switch of the s nnets. It to understood that the load 5. Vices shown by the ical device and the any circuit encr iencs will position, circuits sources of energy ewise gizer. Various other themselves to those chil thesrt. I

In Figure 7, movable cc ct represents the shcrt-circuiting element of member 26, and corresponds to the movable contact as of Figures 2 to 5 as well as projections 3Q, 39 of figure 6 as will be understood. An important feature of the invention is the circuit interrupting action such as for the A and B circuits, accomplished in series-break relation between two contacts and the movable contact member. Sparking between any one contactand the movable contact is reduced to below half as compared to the sparking occurring in the prior equivalent switching arrangements for a given current. The

current carrying capacity of a given switch con- Figures 8, 9 and 10, illustrate another form of the invention particularly constructed to mini-l mize sparking at the contacts and thereby increase the' current interrupting rating of the switch unit. Figure 8 is a vertical cross-sectional view'showing the arrangement of the respective parts. The form is essentially similar to that shown in Figure 2 with the addition or an auxiliar'y contact element 55 interposed between movable contact. 3i and lower contact 56. A-single setof contacts is used for'each side; contact being the lower one extending from post 51, and contact 58 being the upper one extendingtrom post 59, Figures 10 and 11 more clearly show the arrangement of the respective contacteleme'nts.

Auxiliary spring 55 is interposed in the current interrupting circuit between the lower contact 56 and the movable contact 3 I. A set screw 60 passing through an opening in member 26 abuts an intermediate portion of spring 55 for defining, its upper position with respect to contact 58. Set

screw 55 is threaded within cover plate 2| as shown. The spark reduction action of member .55 is accomplished as follows:

When push button 23 is in its normal released position, an electrical circuit is established between terminal ll 01' the movablecontact, terml.

ml 6 I of the lower contact 66, movable I contact 3|, spring member 66 and contact I! in pressure contact relationship. when push button 23 is depressed against the sensitive region oi member 26, movable contact 3| snaps up to the position illustrated in Figure 8, As movable contact 3i moves upwards, spring I! which is biased in the upward direction follows upwards with it. The circuit is first interrupted by the ,member. 65 and contact 66 causing a sparking condition therebetween when the current is sufiiciently large. However, the upward movement of contact 66 is limited by stop 60 to the illustrated position. I

- ther upwards and separates from member 66.

Thus movable contact 8| travels fur- A spark condition is produced between member .65and movable contact 3!. The intensity of. the

spark at any part in this arrangement is substantially less than the spark which would occur between movable contact 3| and contact 66 .if member 65 were absent. Thus, for a given spark enduring capacity of the switch contacts, at least twice the current capacity of equivalent prior switches may be endured.

The contacting areas are coated with a corrosion resisting metal layer such as silver or a .suitable alloy. The illustrated current breaking capacity between upper contact 56 and the movable contact 3| is less than that between themovable contact, spring, member 66 and lower contact 56 as will now be evident. Accordingly, the circuit including upper contact 56 may be used for a minor current function in the circuit. It is to be understood: that spark reducing spring member 55 may be positioned between movable contact 31 and the upper contact 58 in place of the illustrated position, or such additional arrangement may -be used together with the illustrated member 55 to quench or reduce sparking for both contact sets 66 and 66 to armature. A. novel modification of the switch of the in- 26 cool.

Figures 12, 13 and 14 are modified forms oikthe switch for carrying even greater current values with provisions for rapidly conducting away heat generated at the'terminals, for cooling. Figure 12 shows the terminal contact posts." and 'II arranged opposite movable contact 12 carried at the end of flexed member II. Member II is mounted on a post I4 supported in the housing not shown. Dotted region It corresponds to the sensitive area of actuation for the spring member ll in the manneralready described.

Contacts 16 and II are in the form of corrugations providing ventilating or heat conducting fins. The contacting regions I6 and ll of the respective elements 16 and H are fiat along an appreciable width for providing the necessary current contacting area. The vertical fins of contact elements It and H conduct heat away from the current contacting region and lower the temperature in the switch contacting areas. This arrangement greatly increases the current-carrying and interrupting rating of the unit.

Figure 13 is a fragmentary end view of another form for cooling the switch of the invention to increase its currentrating. Switch member 13' corresponds to the spring switch 13 of Figure-12 and is arranged to carry substantial current. To preserve the springiness of the member and provide proper operation thereof under high current values, cooling fins 66 and Bi are arranged on opposite sides ofmember 13 longitudinally along the length .thereof and positioned as closev thereto as practicable to permit proper up and down movement thereof. 80 and fl are of sheet material and arranged to give a large heat conducting area for maintaining the region adjacent the surface of member They are attached to enclosure 82. A

. push button 65 is arranged to press against the vention is illustrated in Figure 11 and encompasses a; telegraph key. The switch included in housing 6'i'is the type disclosed inthepatent hereinabove referred to. as generally illustrated in-Figures-l to 10. A spring actuating element corresponding to element 26 is located within casing 6i and is actuated by push button 62 at the sensitive region thereof corresponding to region -33 indicated in Figure 3. A small displacement of push button 62 of the order of a thousandth of an inch will cause a marked displacement of attached to a leaf spring 64 secured at 66 to the top of switch 6|. Spring 64 passes over pushbutton 62.' Spring 64 extends beyond the side of the housing 6!. Knob 63 is attached to the.

free extending end of spring 64. Relatively small pressure and movement of button 63 causes large displacements of the internal spring member 26 (not seen in Figure 11) which is capable of interrupting relatively large currentvalues for the circuit without sparking or corrosion. The telegraph key is readily manipulated without tiring by the operator. The extended end of spring.

permits the operator to move button 63 even beyond the required amount,.serving as a keying shock absorber. The 'springiness in spring 64 makes the actual displacement of button 63 noncritical as will now be evident, without interfering with the switching action of the switch contained in ii.

sensitive region of member 13 in the manner already described and projects through the upper fin as shown.- Vents 86 are provided in the housing 82 adjacent the cooling fins 80 and 8| to provide proper circulation therefor.

A further form of the invention for minimizing and extinguishing sparking is illustrated in Figure 15. A permanent horseshoe magnet 90 is an ranged with its poles 9|, 6! adjacent the switchmovable contact ii to actuate the electrical contacts in the circuit.

A manually operable button or knob 63 is shown ing region including contacts 621-93 andmovable contact member 84. The magnetic field of magnet 80 passes across the gaps of the switching members. The magnet is encased in the housing base 66 which supports the switching member as well. The switching element corresponds to element 13 and 26 of the above modifications, arranged for actuation with small displacement and pressure of push-button 91. Magnet is of the type having high permanent magnetism characteristics, to effect a strong magnetic field across the sparking gaps without materially increasing the volume of the switch. Magnet 66 is imbedded in a suitable recess provided in base of the housing.

Figures 16 to 20 illustrate a form of the invention designed for very small and compact size,

with a minimum of parts for lnexpensiveness and ruggedness. A switch of this character, as illustrated in Figure 16, may be constructed with dimensions of the order of an inch to one and a half inches in length and about one-half inch in width andonly about three-sixteenths of an inch in height. Figure 16 is a perspective view of the switch unit enclosed. in casing Hill with connection lugs IN and I62 projecting at opposite ends thereof. A grooved region It! is ar- Corrugated elements aasacac sgcd ccntrally oi the nicided housing 1% to r vidc a clamp "tor securing the unit to base. sci-cs i7 and i8 respective and end of the novel compact The switch lolly comprises or: mldcd enclosure which may be of car iite or other mg the parts and oppos d longitudinal legs Cl. ss-sectional views, and till are the housing between housing and ,er tit. Electrical coniie iordcd between electrical. contact Hi2 and the *ing member Ht. ring or ill? corren to member 2?} th "-s mbcdimcnts d is properly bowed or Jhe manna vionsly referred ,rov d sensitive on -cooperati sh .rtton ill for I into a cot construc id ceramic itch parts tnation. spring memon is accordingly at movahie mica tor other i r m inside tit of cast: g -tion spacer or bionic Lug l ;c casing itit "3? rivet t with hi i thcrebetween.

god to co- -.ct m for action. An c 5;: er, a Bakelite" sheet or the like. is scoured with rivets Edd-497i to provide a bottom protective covering for the switch elements. A spacer H8 inextent sures proper room between displaceable member Hi1 and strip iii.

The switch of Figure '19 is a normal-make type. The same components may be used to form a nor mal-break switch as illustrated in. Figure 20. The difference in construction comprises in reversing the position of contact lug ii and block H6, placing extension NI of the lug adjacent face MB of casing iW, properly spaced from movable contact H2 to establish electrical connection therewith when it is displaced upwards by pressure from button I I i. The novel interchangeability of switch construction vwith great simplicity of arrangement and form are important features of this invention.

Figure 21 illustrates a useful embodiment em ploying the simplified, compact, light-weight switch of Figures 16 to 20 as a minute but effective telegraph key. A flexible leai" spring I20 is seecured at one and I2! to thetop of switch casing 500. The free end I of spring 120 is longer than the switch and extends substantially beyond. The intermediate portion of spring I20 is spaced above switch H38 and is arranged to coact with push-button IIi'. As shown by the dotted position, spring lever I 25 is not limited in its excursion, and presents smooth keying without jar or strain. Lever I2li operates on button iii which in turn depresses the sensitive biased region of switch member I In to in turn disis secured rib-ohcnn place movable contact H2 with respect to the 7 this of switch corr sec-tic A further important mod iicaticn oi the invcnat the ca by caps through a weiding or other su table j connection. it push button iii: is arranged on one face of bonding or actuating the sensitive switch within the and. yet permitting an air tight soal therefor. hash button consists of a diaphragm or halt as its held in position by a reta ring cared to the casing. connections its are passed through openings in caps d establishing suitable electrical connections to the contained switch. The ends i5! are sealed about the wires with suitahie sealing material preferably of an insulation nateriai etch was". r the like, to prevenu moisture or air from entering. It s icasibic to emplo only one all terminal co nections in place of the two shown.

Figure shows a rcrnent for .o a crossre, The

L9 view along 253- so.

housing ll is of metal. The switch dcvicc, trncted integrally with irradiationat act-tire i i-d. is similar to the hcrcinahovc units 4 except in that rihbed regions iii are icngitndinaily oi the member; to coact ls integral with casing 550. The l arrangement hitidi; rigidly holds switch unit fitiil within the enclosure H8.

The diaphragm push button 6&2 comprises the diaphragm 553 having a flexed annular region 558 near its periphery. The edge of diaphragm W3 rests in a. recessed portion at 55$ of the housing. The retaining ring is screwed in proper threading in housing 85?: adjacent the .edge of diaphragm 53. This type of push button permits sealing of the unit irom external space and yet permits a. sensitive push button arrangement for actuating the spring member 565 within the switch.

Spring member 955 is similar to the springs 25 and I3 of the hereinabove described modifications and is flexed or bowed to have a sensitive region at ISG. In the illustrated form, 'a rod i 61 is attached to the sensitive region I68 and projects through the structure 860 beneath the central portion of push button 152. A projection 368 is secured to diaphragm I53 opposite and closely spaced from rod I6! as shown in Figure 23. A small pressure and/or displacement upon button I52 will communicate corresponding action on rod I 61 to the sensitive region I65 of the spring member I85 and operate it in a manner already described for switching the currents flowing in the switch. It is to be understood that rod It! need not be attached tomember I65 but rather project integrally with portion I68 of thcbutton down to the sensitive region of member I65 in a manner of the previous push buttons described.

The joints of the enclosure for the switch are sealed for air-tightness. Thus, the ends of push button E52 including the retaining and sealing ring I56 are treated with varnish, GlyptoP' or other suitable material for sealing this region of the switch casing ltd. As already described. the joints between caps It! and easing I50 are welded for air-tightness; the openings through caps ii for terminal wires and W are also properly After the switch cscmbled for use in the manner described and illustrated, sparking within the switch will very quickly burn up all the available oxygen therein, leaving wholly inert gas in the sealed switch. The deleterious eil'ects on the materials due to arcin are thus greatly minimized. A further advantage is that the switch may be employed in dusty, humid or wet places without affecting its electrical characteristics.

Although I have illustrated several embodiments of preferred forms of the present invention, it is to be understood that modified ar rangements and constructions are feasible fall-.

ing within the broader spirit and scope of the invention. Accordingly I do not intend to be limited except by the following claims.

I claim: 1. In a switch of the character described, the

combination of a biased leaf spring having a conductive element at one end, a ceramic casing having, crosswise, a U-shaped section and lengthwise an upstanding end wall at one end providing a surface for positioning the-other end of the leaf spring to be clamped, a contact plate, arranged adjacent the conductive end of the spring for making electrical contact therewith,

said plate being mounted at the other lengthwise end of said casing, and aninsulating cover fitted lengthwise within said casing covering the open side thereof and having clamping elements at either end, clamping at one end said leaf spring and at the other end said contact plate.

2. In a switch of the character described, the

.combination of a biased leaf spring having a conductive element at one end, a ceramic casing having, crosswise, a U-shaped section and lengthwise an upstanding end wall at one end providing a surface for positioning the other end of the leaf spring to be clamped, a connection lug having a contact portion arranged for electrically coacting with said conductive element and a spacer block for positioning the contact portion of said lug in circuit make or break position with respect to said conductive element, said contact portion and spacer both being mounted on the other lengthwise end of said casing and an insulating cover fitted lengthwise within said casing covering the open side thereof and having clamping elements at either end, clamping at one end said leaf spring and at the other end said contact plate and spacer.

" WILLIAM DUBILIER.

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