US2840657A - Two circuit snap switch - Google Patents

Description

June 24, 1958 J. o. ROESER 2,840,657

TWO cmcun SNAP swncu Fi led March 23, 1955 3 Sheets-Sheet 1 G INVENTOR. 475M 206.92,

June 24, 1958 J. o. ROESER 2,840,657

TWO CIRCUIT SNAP SWITCH Filed March 23, 1955 5 Sheets-Sheet 2 I In 'lll' I I June 1953 J. o. ROESER 2,840,657

TWO CIRCUIT SNAP SWITCH Filed March 23, 1955 3 Sheets-Sheet 3 ZJZW - in order to have relatively long service life.

United States Pate TWO CIRCUIT SNAP SWITCH John O. Roeser, Chicago, 11]., assignor to Illinois Tool Works, Chicago, 111., a corporation of Illinois This invention is concerned with the electrical switch v -art, and more particularly with a snap switch mechanism.

More specifically, this invention relates to a single pole, double throw switch of the type frequently called a two-circuit switch. It differs from ordinary single pole switches in that it is provided with four terminals, and a bridging contact member is adapted selectively to contact either of two pairs of terminals to complete a circuit. This type of mechanism is characterized by high electrical interrupting ability, long contact life, more adaptable circuity and good vibration resistance with a small case.

, Snap switches of the foregoing type currently find wide use in aircraft, and also find substantial use in industrial and business machine use. Prior switches of this type often have required critical tolerances and special heat treating. They often have relied upon flexible spring blades which must be made of critical materials Different constructions have been necessary in order to impart different characteristics to the switches.

' Accordingly, it is an object of this invention to provide a two-circuit snap switch comprised of parts which do not require critical tolerances and need not be heat treated in fixtures as in the prior art.

It is another object of this invention to provide a twocircuit snap switch utilizing a spring having a very long mechanical life.

Yet another object of this invention is toprovide a two-circuit snap switch, the characteristics of which readily may be changed without reconstruction by the substitution of a different spring.

More specifically, it is an object of this invention to provide a two-circuit snap switch utilizing a dead centering coil spring as an actuating agent.

A further object of this invention is to provide a twocircuit snap switch which can be made entirely of noncritical materials. x V

A further object of this invention'is to provide a twocircuit snap switch utilizing parts of simple design, thereby I allowing the use of high temperature materials which often are hard to work in complicated shapes. 7 It is another object of this invention to provide a two-circuit snap switch having an improved guiding action for' the actuating member, thereby providing an 9 V I v Prior artterminals often have not been capable of I satisfactory mounting in a plastic case so as to be secure against accidental removal through abuse and. so that they will not be loose or in any, way rattle} It will be zontally disposed slots30f." These slots open at one end understood that undercuts are to be avoided in molds...

for plastics in general, and that therefore special con shown in Fig. ll; and

, 2 figurations of plastic cases generally cannot berelied upon to hold terminals'properly in place. Q

Accordingly, it is an object of this invention to provide a terminal avoiding the-foregoing difficulties.

More specifically, it is an object of this invention to provide a terminal cooperating with a plastic case wherein the terminal is provided with portions snapping into position in the plastic case for a secure mounting of the terminal. Y

Other and further objects and advantages of the present invention are to provide a'two-pole four-circuit snap switch possessing the same advantages as the two-circuit single. pole switch heretofore described, and to provide means in such a switch positively insuring simultaneous operation or'snaprnovement of all of the moving contacts thereby to insure against improper switch operation.

Additional objects and advantages of the present invention will be apparent from the following description when taken in connection with the accompanying drawings wherein:

Fig. 1 is a perspective view of a switch constructed in accordance with the principles of my invention;

Fig. 2 is a longitudinal sectional view generally corresponding to a side view with the cover of the case'removed;

Fig. 3 is a vertical cross sectional view taken along the line 3-3 in Fig. 2;

Fig. 4 is an exploded perspective view; a

Fig. 5 is a horizontal sectional view taken substantially along the line 55 in Fig. 2;

Fig. 6 is a view similar to Fig. 2 showing the parts in a different position of operation; 1

Fig. 7 is a sectional view of the main portion of the case with a part of the case broken away; 5

Fig. 8 is a perspectiveiview of the cover for the case;

Fig. 9 is a horizontal detail sectional view showinglthe mounting of the terminals as taken substantially along the line 99 of Fig. 6; a

Fig. 10 is a vertical cross sectional view through the terminals taken substantially along the line 10-min Fig. 6;

Fig. 11 is a side view partially insectionwith the cover .of the case removed generally similar to Fig. 2 and showing a two-pole, four-circuit switch;

Fig. 13'is a fragmentary sectional view similarto the central portion of Fig. 2 disclosing a modified structure wherein buttons project from opposite sides of the switch housing. g

Referring now in greater particularity to the drawings, and first to Figs. 1-8, there will be seen a switch constructed in accordance with the principles ofmy invention and generally identified by the numeral20. This switch comprises a housing having a main portion or body 22 and a cover 24. The switch case or housing .is made of any suitable insulating material such as plastic .Bakelite being a preferred example, and thecover- 2 4 is held on the body 22 by any suitable means such as rivets (not shown) whichare passed through a pair of aligned apertures 26 having enlarged counter bores at -,their opposite ends. iently are diagonally disposed relative to .one another on The aligned apertures 26 conven the case, 'and another pair of aligned apertures 28 completing a rectangular arrangement with the apertures 26 is provided for the receipt of mounting screws to hold the switch in any desired operational location and position.

The main portion or body 22 of; the case is provided at its opposite endswith pairs of vertically spaced, horion the open side of the body'and are closed off by the "dover 241 It will "be observed with reference to Figs. Wand 8thatth'e cover is providedwith a peripheral shoulder 32 fitting about a complementary boss or projection ,Srtfon the body 22in order accurately to position the waver on the 'body, j and also substantially. to seal the case. Aligned with .eachofthe slots 30 is ,a'pair of cir- Tculai'hol'es or l recesses 36 on a shelf 38 projecting from V the back wall t of the body; :Pairs of recesses or holes i'iZXFig. ,8) are providedin raised shelves .44 and 46 on dt he front Wall 48 of the cover.v The slots 30 and the a'lign'edpair's of recesses .36 and 42 cooperate to receive and support inserts 50 providing attachment term inals and also :providing fixed .contact supports.

."E'ach of the inserts as best may be seen in .Figs. 4, 7'

10 comprises a-substanti'ally rectangularbodyporltionhaving a terminal lug ortear 52 projecting ,outwardfly andto onenside. The lugs 52- are provided with aperiure s 54, and the upper. and lower inserts are relatively .;reversed so that the lugsor ears project in relatively oplpositesdirections to facilitate connection of wires-thereto. 3 Each insert 50 also'comprises. two pairs=of opposite- .lyextending paralleltfingers .56. The inserts are stamped from a fiat sheet of spring material such as brass, and Abe outer ends of each-pair. of fingers 56 approach one another more closely than'do the innerends, The fin- -gers 56 B.I;Of a proper size todit into the recesses 36 t and 42,-bu t theouter.ends of the fingers arelspaced slightly closer, for instance .005 inch, than are the corresponding recesses. Thus, the 'insertfingers must be snapped into the recesses and firmly grip the walls thereof to hold the inserts :in place.

Inaddition to then-foregoing vparts each insert is provided with an aperture in the body portion thereof, anda contact element 58 of suitable conductive material, preferably silver, is. riveted into each of Jthesexrecesses win accordance with conventionalcontact mounting practice. r

Itwill be apparent from the drawings and .from the foregoing description that the contact elements 58 thus i tare mounted at opposite ends of the case in vertically spaced pairs, the elements being aligned with one another engagement by 'a vertically movable double- -fior selective faced'contac.

The body 22" is provided at its center with aivertical guideway 60 opening; towards :the interior of the case, "and a's'irnilar guideway 62 is provided in the cover conator button in th e raised position of Fig. 2 as previously "below {the-contact .blades92. The inner ends of the blades, i. e. the ends 100 of the legs are sharpened and 'seat in the grooves 88 on opposite sides of the aperture '78. A coil spring 102 extends through the aperture 78 and is anchored at its opposite ends in small apertures v164 .in the bight 96 immediately adjacent to thedouble- [faced contact buttons 98. For the best possible switch action the apertures 104 anchoring the ends of the spring 102 are positioned as near as possible to'the contact but- .It'on .98.. However, it is contemplated that tongues of T greater or lesser. length could extend parallel .to and gspacedfrom the legs 94 from the bights to provide spring .auchors that are closer to .one another and relatively remotely disposed to the contact buttons.

h h 7 However, it has been found that switching action in this case is inferior. The switch blades 92 best are made of a resilient .springrhaterial, and beryllium copper is a preferred example. The contact buttons 98 preferably are made of 1 silver, similar .to .the contact elements -58,and -the coil spring 102 spring steel.

is or conventional construction, commonly Thespringl84 normally holds the actuator and actuf has been noted. aThe tension spring 162 urges the arms fronting the guideway-60.' An actuator 64 is arranged for vertical reciprocation in these guideways and comprises a .sheet metal stamping of brass or the like-of *ratherl'subst antial thickness, The actuator is provided a was generally rectangular" body portion having-a re- "duced upstanding tongue 66. A plastic button 68 fits over this tongue and down against the shoulders 70 at 'the top' ofthe-body portion 'adjacent'to tongu'e 66. The button is of rectangular cross section and 'is received mostly in a recess in the top wall of the case-body,

or contact lbladestoward one another in a downward indirection so that the contact buttons 98 engage the lower two contacts 58. When the button 68 is depressed against the force-ofthe spring 84, the pivot of the con- ;tact blade92comprising the, grooves 88 is lowered toward a dead-center position relative to the spring 102 and the portions of the contact blade in which the spring is anchored As soon as the pivot passes this dead center position the contact blades are snapped'upwardly by the 'spring 102 to cause the contact buttons 98 to engage the upper pair of contact elements 58. This upper contact po sition is shown in Figs. 6 and 10. It will be apparent that the two-contact buttons 98 move substantially; in

synchronism inasmuch as both buttons are snapped by the spring 102 as soonasthe pivot passes dead center as heretoforehas' been noted. When the button 68 is released the spring 84 returns the button and actuator a dead-center, and the spring 102 this time snapping the and partly in a recess 74 in the cover, the two recesses.

cooperating to form -a rectangular opening complementary to' the button 68. The buttonis provided with -an'outwardly projecting circumferential flange 76 at its lowermost edge to limit'upward movement of the button and actuator.

to the uppermost position, the pivot again passing through contact 'button 92 down into engagementwith the lower ,contactelement '58.

.lt rwillvbeapparent that the switch mechanism heretofore described is. aspring-return switch. That is to say,

the spring 84 normally maintains the actuator in the raised position 'of F ig. .2 so that a circuit is completed between the lower. contact elements 58 by means of the i The. actuator is provided in the body thereof with a vertically elongated slot .78, and with a downwardly projecting spring 1ocator-80, and apair of downwardly.

projecting legs 82"spaced to either side of the-springlo- 'cator." A coil spring-84 fits about the projection'tltl and,

between 'the legs -,82 andis positioned in a-recess 86 in "thefcase body 22. This spring normally 'urge s-the ac'tuator 64 and the button '68'thereon upwardly to theii'upward limit of movementasshown in.Fig. 2;"

f The ac tuator '64 i'sj jarovidecl onitsopposite faces with" i I y shaped grooves '88. I-hese L grooves arehori'z on'tally g a Ear-i es ar swamp st e contact .buttons'9, the contact blades92 and the actuator.64. The: upper pair of contacts 58 is similarly connected only when the 'button68 is held down. It will be apparent ,that. ;the spring 84 could be omitted, and a tongue similartozthe tongue 66 could be provided on the lower end of the actuator for cooperation with asecond button 69, as. illustrated in Fig. 13, projecting from the bottom of the switch. The switch thuswouldbe manually operated in veither direction and would remain in Qwhicheverdirection it was actuated untilafsuc'ceeding actuation in the opposite direction. 7 0

As has been, noted heretofore the principles of my invention. can be applijed.equally well. to a two-pole, four circuit switch. Such a switch is, shown inFigsf l1 and j 12. ItI'willbenoted in these figures that theconstruc- .tion is generajlly similar to that heretofore shown and ,described witha fduplica'tion of certain other parts and contacts 58b. e

I center position.

merals with the addition of suffix a. Certain of the parts which occur in duplicate in the modification of Figs. 11 and 12 are identified by the same numerals heretofore used with the addition of the suflix b. The body 2211 and cover 24a of the case areof substantially the same length and thickness as in the original embodiment of the'in-' vention, but are. somewhat higher. The case further is provided with a horizontal divider wall 104 extending from one end to the other of the body 22a and from side to side thereof. The horizontal divider wall 104 'is .provided with a transverse slot or guideway 106 foraccommodating the actuator 64a. Inserts 50d and 50b are provided in duplicate pairs and arereceived in duplicate slots 30a and 30b in the ends ofthecase body., The

horizontal divider wall 104 is provided with oppositely disposed recesses 10,8 at'its opposite ends for accommodating the butts of the lower contacts 584 and the upper The actuator 64a is provided with two pairs of V- shaped grooves or recesses 88a and 88b on opposite sides of an insulatingbar 109 in the actuatorreceiving the knife edges of two pairs of contact blades mama- 9217.

The aperture 78a in the actuator is sufficientlyelongated in height to accommodate a pair of tension springs 102a and 1021) stretched between the ends of each pair of contact blades. It willbe observed in Fig. 12 that each of the contact blades is provided with a central tongue spaced between and extending parallel to and in the same direction as the legs or arms 94a and 94b. These tongues are numbered 110 for each of the contact blades and provide spring anchors spaced inwardly a short distance from the contact buttons 98a and 98b.

The purpose of the tongues-in this embodiment of the invention as opposed to the previous embodiment ing material such 'as plastic and fits through a recess 116 in the horizontal divider wall 104.

. Operation of the switch shown in Figs. 11 and 12 is generally similar to that previously disclosed. Depression of the operating button 68a, and hence of the actuator 64a, against the force of the spring 84a causes the contact blades 92a and 92b and the springs 102a and to move toward dead center positions. Generally speaking, one of the pairs of switch blades will trip first while the other is Very near its trip point, say within .005 inch. The contact blade that first trips will fly through the' air unrestrained, by virtue of a slight lost motion connection between the blades and the shift rod by virtue, of forming the grooves in the shift rod slightly wider than the thickness of the contact blade, the lost' motion generally being "on the order of about .008 inch,

, until it hits solidly against the shift rod. The momentum gained by the moving contact blade hammers the other blade over center. blade, or pair of blades, is accomplished very easily since the second pair of blades is poised in substantiallydead It will be, apparent that the shift rod is held against transverse motion by'the tongues 110 and adjacent arms or legs 94b: "and 94b, and is held against longitudinal motion by fitting in the recess 116 in the horizontal dividing wall 104.

j The switch again has been illustrated as a spring return type, but it will be understood that it readily could be made as a two-position manually actuatedswitch by.

elim nating the spring 84a andxproviding a second push This over-centering of the second button in the bottom of the casefittingon a ten ueat the bottom of the actuator.

' It will be understood that each contact blade could comprise a single central leg with two springs on the opposite; sides thereof. Furthermore, the grooves or notches 88, 'rather thanbeing positioned directly opposite one another, could be offset to provide a predetermined sequential action.

It now will be: apparent from the foregoing description that the parts of this switch do not require critical tolerances, and ,that the parts need not be heat treated in special fixtures as usually is necessary. fThe switch can be constructed'of non criticalmaterials, and high temperature materials readily can be utilized since there are no complicated shapes to be formed. The helical tension springs. utilized for the snap action have-a very long mechanical'life'," andthecharacter'istics of the switch may bechanged easily without any changes in'tooling simply by using different coil springs. "The actuator is supported substantially over its entire length so that the operating button has an exceptionally good bearing. This helps .to. maintain good alignment so that thecontacts are accurately positioned. Furthermore, it will be each of said blades, said abutment means being carried appreciated that there is a desirable and positive wiping action of the contacts which tends to keep the contacts 'clean,and facilitates breaking loose of sticking or welded contacts.

v The particular structural embodiments of the invention heretofore shown'and described will be u'nderstoodas being for illustrative purposes only Various'change's' in structure will no doubt occur to thbsskilledth art, and are to be understood as forming a part of my invention insofar as. they fall within the spirit and scopeof the appended claims. I i

The invention isclaimed as follows:

1. A snap switch mechanism comprising an insulating support, an actuator mounted in said support for slidable movement from a normal position to a second position,

switchfblades being generally flat and each' consisting of a pair of spaced'arms interconnected at one end thereof 'by a bight portion, said actuator'having generally opposed means to provide a pivot forsaid blades and located onthe actuator in a mean position between extremes of sliding movement of said actuator, a helical spring stretched between said; switch blades and attached to m e'ans integral with each bight portion, electrical contact means carried by each of said switch blades substantially at'the outer ends thereof, and a pair of spaced abutment means respectively on opposite sides of each switch'blade in a position substantially adjacent the outer ends of by said support and disposed substantially about the mean 4 position of said'pivot, a corresponding one of each pair of abutment means comprising an electrical contact aligned with the corresponding contact means carried by the switch blade, said switch blades synchronously snapping from a normal position engaging one of each pair of said abutment means to a second position engagl g he other of each pair upon slidable movement ofv a actuator past a dead center position relative to said blades said actuator to carry the' pivots of said blades on the and spring'means, said blade's in one of said positions effecting with said contact means carried thereon a bridgtransversely of its elongated axis, and a second cavity 75.} extending longitudinally of said case and emanating ont- 'wardly in both directions from 'said channel shaped cavity,

7 jan' actuator ;;transverse1 shaped cavity for slidable moye nent gfrem ,a normal mmonia :a second po t n d--atuam qqm i an el ngated member of conductive material having an z elongated aperture therethrough along its longitudinal axis anti -within the margins, thereof,- a dielectric. button iattachedxtoone end of said actuator, and movably pro jecting through one side of said case,whereby depression ,Qi said button will :move said, -;actuator from .a 7 normal iwwfii ion to a seeond-positiommeans to return said actu-,

star :from: said second position gto its normal position, a pair-of disereteewitch blades' pivoted on said actuator aand' zextendinggenerally =oppositely to one another and 1 transversely of saidactuator ;into the longitudinal .cavity 30f said case, said switch blades being ,generally flat and 1 each of a pair of spaced ,arms interconnected rat one end thereof by a bigh portion, said actuator being q provided with-a pair, ofnotches on opposite sides thereof in generally opposed position, said, notches being posiand1extending"outwardly from, and. on opposed sides of, .said elongated aperture and transverse tothe ,:longitudinal axis of said actuator, thefreeends of tthe -;s pa ced arms on each blade ,being positioned within adja-. cent] notches, said notches providing a pivot cfor,.the

hlades on ;said actuator having ameanposition between: ztextremes of sliding movement ofsaid actuator, a single metallic coil spring stretched throughthe elongated aperturc in theactuator between said switch blades and .attacliqd to -eachwblade on its bight portion, electrical pontactsmeansrcarriedby each of said switch blades sub-v stantially at the Outerends thereof and ,extending on gppgsite sides of each-blade, a pair of spacedabutment ;,,rnqtins located at each end of the longitudinal cavity, in

the case and substantiallysymmetricallyidisposedinplanes about the mean position ofrsaid pivot a corresponding.

aoneyof each pain of abutmentmeans comprising an electrical v contact ,aligned with ,thecorresponding contact means, on the adjacentv switch blades, said switch blades asynchronously snappinggfrom a position; engaging the z ,,o ther of eachpair of said abutment means to a position,

j corresponding abutment means.

7 3. A snap switch mechanism as set forth in claim 1 -wherein the case is provided in' its opposite'cnds with a painpf spaced apart parallel slots, at least in said body,

' substantially fiat metallic zinserts received in said slots and ,extending outside of said case and inside of said -ca e, ;said inserts providing saidjabutment means and also 1 providing electrical terminals, said inserts having oppositely extending pairs of resilient fingers coplanar with said body, each pair of fingersextendingin the same 1 direction: and having confronting lateral edges, and an abutment inside said case cooperable with each pairof resilient fingers and resiliently gripped between saidcon- 1 fronting lateral edges of-such fingers for holding said flinSBItS in place. i v a 1 1 4. A snap switch mechanism 'as set forth in claim 3 wherein the abutments receiving the 'fingers comprise sections of material between spacedrecesses in the case ,1 body and in the case cover. A 5. A snap switch mechanism as set forthin claim, 2 wherein the K103115510 return said actuator from said secondzposition to itsnormalgposition includes a second dielectric button attached, to the end, of. said actuator opposite .from'said first mentioned button, and ,movably projecting through theaopposite sidezof .-sai d case from said first mentioned button;

, .,6. A-snap switch-meehanjismas set. forth inclaim 2 I herein said N actuator is fl,11f l; .er provided. at the -end mounted ;in ,said channel cences? oppositetosaid dielectric button, with a recess opening voutwardly from, said .end and having a convex portion at the bottom/thereof which is spaced from and partially ,encircles one ,end of said elongated aperture, .spring ,means positioned within said first mentioned channel shaped cavity, biased between said'case and said actuator, said convexportion of the actuator cooperating to center and retain said spring means whereby said spring means ',serves to return said actuator from said second position to its normal positionupon release of pressure from said ;7. A snap switch mechanism comprisin'g an insulating support, an actuator mounted in said support for slidable 'and extending generally oppositely of one another and transversely of said actuator, coil spring means stretched 20. l v l M sides ,of each switch armsubstantially at the outer end between each pair of switch arms, electrical contactmeans carried by each switch arm substantially at the outer end thereof, a pair ofspaced abutment means on opposite thereof, said abutment means being carriedbysaid sup- :port, acorresponding oneof eachpair of abutment means comprising an electrical contact aligned with the correcorresponding one" of each pair of switch arms toinsure subst'antially simultaneous movement thereof, said switch armsynchronously" snapping from a position engaging QIlEQLefiCh pair of abutment meansto a position engag- 7 said actuator to carry the pivots of each pair of arms on said actuator past .a dead center position relative to'said rpair of arms and the corresponding spring means, said arms in one of said positions effecting with said contact ing the otherof. each, pair uponslidable movement of lostmotion connection.

9. A snap switch mechanism as set forth in claiin 7 wherein the linking means comprises an elongatedinsu- "lating member having a plurality of grooves therein receiving the linked switch arms.

10. A snap switch mechanismasset forth in claim 9 whereineach switch arm is substantially U.-shaped having a bight. and a pair of arms extending therefrom, said bight being positioned outwardly from the actuator, and a tongue extendingfrom said bight substantially parallel to'said arms and in the same direction, said tongue and one-of thearms fitting in the groove of said insulating member.

References Cited in thefile of this patent UNITED STATES PATENTS 1,578,485 Todd Mar. 30, 1926 1,586,713 Sjolin June 1, 1926 1,645,528 Gordon Oct. 18, 1927 1,907,869 Raney f May 9, 1933 1,969,304 Grooms Aug. 7, 1934 2,194,533 Van Dyke' Mar. 26, 1940 2,332,911 Hausler Oct. 26, 1943 2,486,033, Kaminky Oct. 25,- 1949 2,517,845 Cooper Aug. 8,1950 2,518,255 Roeser Aug. 8, 1950 2,565,790 Van Ryan et al. Aug. 28, 1951 1 2,629,791 LcTourneau Heb. 24, -1953 2,650,973 Jacobi Sept. 1, 1953 FOREIGN PATENTS 40,818 Denmark Sept. 23, 1929 474,919 Great Britain [Nov. 10, 1937 567,471 :Grea'tBritairi Feb. -15, 1945 927,s,7 9 Germany May 12,1955

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