US2697142A - Snap switch with oscillating knob - Google Patents

Description

v. R. DESPARD 2,697,142

SNAP SWITCH WITH OSCILLATING KNOB Dec. 14, 1954 Filed Sept. 5, 1951 .l INVENTOR. VICTOR R. DESPARD AT TORNEYS United States Patent O SNAP SWITCH wim oscrLLArlNG KNoB Victor R. Despard, Syracuse, N. Y., assignor to Pass & Seymour, Inc., Syracuse, N. Y., a corporation of New York Application September 5, 1951, Serial No. 245,107

20 Claims. (Cl. 2006) This invention relates to electric switches, and more particularly to wall switches of the so-called alternating current type adapted to be actuated by an oscillatable knob.

It is a general object of the present invention to provide a novel and improved switch of the A. C. type having a knob actuator intended for relatively small angular movement in either of two directions for actuating the circuit opening and closing mechanism.

More particularly it is an object of the invention to provide in a switch of the type described combined resilient contact carrier means and buing or motion limiting means for the actuating knob.

An important object of the invention comprises the arrangement of a switch housing with projecting actuating knob and guiding spindle journalled therein, together with a stationary contact and a cooperating contact intermediate the ends of a cantilevered spring whose free end is engageable by a projection on the lower surface of the knob for actuation thereby.

Another important object of the invention consists in the arrangement of an oscillatable knob having an axial spindle fitted with an over-center spring for urging the rotation of the knob in either of two directions when it is manually moved beyond the center, together with a knob motion buffer and contact carrying system including a spring cantilevered from the housing and having a free ind positioned for cooperation with a projection on said nob.

A still further object of the invention comprises the arrangement in a three-way A. C. switch of a pair of parallel spaced cantilevered springs mounting intermediate their yends contacts for engagement with straddling stationary contacts and incorporating an operating mechanism of the oscillatable knob type having an over-center spring wherein the free ends of the contact carrying springs are received in slots in the knob for movement by the walls thereof and for limiting the motion of the knob under the action of its spring.

One of the important features of the present invention resides in the construction and arrangement of the switch parts to produce contacting operations which vary from quiet to silent by the elimination of snap action and leaving control of the contact carrying spring with the operator until contact is made.

Other and further objects of the invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawing and following specilication, wherein there is depicted the single exemplary embodiment of the invention, with the understanding that such modifications may be made therein as come within the scope of the appended claims without departing from the spirit of the invention.

In said drawing:

Fig. 1 is a longitudinal central section through a switch constructed in accordance with the present invention;

Fig. 2 is a top plan view thereof with the cover and knob removed and the operating spindle in section;

Fig. 3 is a transverse central section taken on line 3-3 of Fig. 1;

Fig. 4 is a bottom plan view of the cover showing the under face of the knob disk and its operating projections, the upper free ends of the contact carrying springs being illustrated in dot and dash lines to show their cooperation with the operating projections; and

Fig. 5 is a view similar to Fig. 4 but illustrating a modi' 2,697,142 Patented Dec. 14, 1954 tcation in which limit lugs on the cover determine the maximum movement of the contact springs.

The switch of the present invention is primarily intended for but not necessarily limited to use in wall and switch boxes for general interior wiring and may be mounted in multiple with other wiring devices in a single gang box in a known manner, by being supported from a strap or bridge plate. For this purpose it is shown as tted with a suitably shaped and sized housing 10 of molded insulating material having a closed bottom wall 11, closed side walls 12 and similar longitudinally slotted end walls 13. The top is open, providing a large interior chamber intended to be closed by a cover plate 14 of insulating material and having a protuberant neck 15 for mounting in the strap and acting as a guide for the operatingknob assembly 16, which includes the external longitudinally uted portion 18 for manual manipulation, the interior bearing portion 19 and the enlarged bottom disk or radial flange 20, equipped on the under surface at the periphery with the spaced operating lugs 21, 22 and 23.

The operating knob assembly is molded about or otherwise attached to the upper end of a sheet metal spindle 25 axially disposed and extending from the lower or disk end thereof and having a narrowed lower end 26 the edge 26 of which is at the axis line. This end 26 is received in opening 27 in the bottom wall of the housing. The opening is V-shaped as shown to provide a fulcrum for edge 26'. The under face of the cover 14 of the housing s provided with a recess 30 for the disk 20 which forms the upper thrust bearing for the knob and spindle assembly.

Integral with the spindle and projecting radially therefrom is the arm 32 which is given a 90 twist and notched at the outer end as at 33 to fit over the wire of an overcenter spring 34, generally of U-shape having the shorter leg provided with a crimped portion 35, the bottom of which engages in notch 33 to position the spring in the vertical direction in the housing. The long arm of the spring rides in a narrow V-channel 36 in the adjacent side wall of the housing. Suicient compression is effected in the assembly operation so the spring acts as an over-center device and throws the spindle to the limit of its oscillatory movement in either direction, if it is first manually passed over-center by manipulation of the knob. Throw limit for the knob is effected by engagement of a projection 37 on the portion 19 with end walls of a channel 38 in the neck of the cover (Fig. 3).

The contact structure of the switch is extremely simple and comprises, for a three-way switch, two sets of contacts each including a stationary contact 40 and a movable contact 41. For a single pole switch one set may be omitted with the associated carrying parts therefor. Preferably, however, the second set of parts may be dummies for a purpose which will appear later. The stationary contacts are supported in the desired position straddling the movable contacts by arms 42 of the configuration best shown in Fig. 1. The contacts are riveted to the right angled ends 43 thereof and the opposite ends are bent out at right angles from integral terminal plates 44 of a width suicient to have their ends received in the channels 45 in the vertical corners of the housing. These terminal plates each received a terminal screw 46, the head of which is accommodated in slot 47 in the end wall of the housing, as shown: These slots have flaring side walls for convenience 1n wiring.

Movable contacts 41 are each riveted intermediate the ends ot' one ar-m 50 of a U-shaped spring 51, the central portion of which is riveted at 52 to connector strap 53 extending longitudinally along the bottom wall of the housing and having an upturned integral terminal plate 54 thereon, which is also received, at one side in the channels 4S in the corners of the housing. The two terminal plates 44 and 54 on the left side of Fig. l are spaced apart vertically by a horizontally arranged barrier plate of insulating material 56 notched to receive the walls of the slot 47 for positioning. The terminal plate of the opposite stationary contact is held in its upper position by resting on a sheet of insulating material 57 in the channels 45 beneath it. The upper edges of the terminal plates 44 are engaged by the housing cover 14 which is in turn held in position by a metal collar 60 3 secured to the housing in a known manner. This maint'a'ns 'the' assembly' and holds all the parts in rigid posiI tion. It will be noted that lthe insulation plate 57 beneath the terminal plate 45 c r i the r i gh t4 side of Fig.r 1 bears on the far 'end of Ithe 'spring carrying 'strap Siv and holds it rig i d. i

Fig. 2 illustrates the jisetj araiig' mehr @f the con: ditemi sirapfsaiopesiiipn the o she sp iiigjetwe nr the stationary contacts which are alo' g. one 'side of t husina Each movable Contact is p'o tion dr'at'y a, no d'al peint in' the length of its ca'n vered'spring 5()V to produce a minimum of vibrationjfor chattering" idrng; the g' operation. The springarisaf'initiallybe ''stibstall` tially the position shown ih the o ne'io' the iight nFig. 1- te insure adequate 'eehiaei epehingjuhde'r ihe urge f ihe spring. Ciqsihg is eifeeted by gageih t eraiejee in boss o r lug 22' on the knob` with eitherof'the springs, dependent upon the 'positioning ofthekn-ob underthe' action of its ever-center spring. Theft'ggzf flexes the spring sufficiently toenga tact with its Statioary coil "terp a it mental exi'ng as shown a t 6 2 in F quate Contact pressu`re. This is a action of the over-'center spring 34. The single central lug 22 vseri'les'to alternately engage the movable contact springs, closing brieand releasing the other to' open its contact by its o 'wn' resilience; Howe ever, in the event that' there shouid be contact sticking from arcing or heating', kicki'oif knobsl or vlugs 2 1 and 23 are provided spaced on opposite sides of the `ope 'tiiig lug but sufiicientlyl spacedl from them to avoid striking thereleaseside of the spring 4until there has-been s'orne considerable movement 'of the itn'ob to provide impact after the knob has Amoved over center'. They, however; do each engageithe back fac'e'of the'cor'resp'ondihg spring, as shown in Fig, 4, when the liiobliasreaehedit" limit ofl stroke, evenl though the springfhasf carriedtlie contacts apart to insure against aiiy'aceidehtal closing'froi'n slib-'tik orvibration.

Mention has previenen beeiiinaaeef he shake hiii'tr ing means 37 for the knob, butt 11 only a safety device to prevent accidentalexcessi veniei'it rilanu"y ally, for the knob is stopped prior toene tive action of this byl the engagemehty of] the ej'rrsiiohfdhig segjf edf tacts and the flexing of the vspring Sil at 62';Y This Ypro vides a cushion or resilient stop for the knob and *qiiiets Atheswitch to the extent that the o ly'solnd prodiiced is that resulting freni the engagement' ofl ih'e'vcoiitaets;

Since the stroke is sho'rt and therspeed 'n't higl'i; tlie i sound is almost imperceptible an can be reduced or stopped entirely by intentional slow' movement' of the knob to the end ofits stroke.

Thus it is possible for the operator ,toreiincontrbl of knob movement until after the contacts engage. In fact in no'rmal'operation tlie foreiingera'nd thumb `rei'naiii on the knob for its full stroke. Since' theA fll'strke is only about 20. this is simple. Tliev springs therefore perform the dual function of carrying th'ejc htacts a"nd limitinga'nd cushioning the stroke of the perating'knoli. The switch is therefore much more" quiej tli'arijihe usual lever type where the Contact elements, Va'tjter initial rriove-y ment, are no longer iinde'control of the lever.

The switch of this invention is small in size, cheap to construct', effective in operation, hasiiicreasedcurrent carrying capacity and has a sinall ii'iirrrberv` ofj siiiip'le parts. It can be adapted for many'us'es; In order to further quiet the switch, the copeating stop lug 37 on the knob and the end walls'f `the channel 33 in which it travels may be eliminated entirely and the construction shown in Fig. 5 substituted. Here they cover 14 for the housing has depending lugs 65 so positioned as to limit the throw of the contact carrying springs to the amount shown in Fig. l at the left. These' lugs are each engaged -by the corresponding tip of the adjacent spring under the urge of operating lug 22 and hence stop motion of the knob assembly in a resilient manner to reduce noise. This arrangement necessitates the use of a dummy spring and contact in single pole switches.- However the cost of the U-shaped spring is not substanf tially greater than an L-shaped one. No contact is needed on the dummy spring and only a yprojectionon the carrier for the stationary contact. Its supporting plate will have no terminal screw.

I claim:

1. An A. C. switch having in combination, a springy leaf fixed at one end, a contact button intermedi-ate the ends of said leaf, a fixed Contact button, means rigidly positioning said fixed contact button to cooperate with the first button when the latter is moved by flexing the leaf, a knob f-or manual manipulation, means guiding said knob for oscillation o'n an axis roughly parallel to that of thesaid leaf, abutnients beneath said knob spaced apart a distance equivalent to several times the thickness o f and straddling the free end of said springy leaf to individually ex the Same and resilient over-center means cooperating withv saidv knob to hold it at either lirnit 'of its movement.

2. The-A'. C. switch of Aclaim l; in which theiixed Aand stationary contacts are provided in duplicate, the stationary contacts facing each other with the iiiovable contacts between whereby the stationary contacts are alternatively engaged 4by their corresponding movable contact, s'id knh having ay -thi'rjdfahuiihehi with one of the hist pair shattering the' second contact spring.

3i In a .switch of the type described, in' combination; ahousing having a chamber therein open at the i015; a cover fori 'said'epeniepg ah openinginsaid em/er, airnbb extending through 'said opening and having. a flange enggii-ig the-'inner facebf the cover, 'a leaf springv having one? endtixed adjacent 'the bottoni 'of said 'chamber and the free end just clearing the ttnd'e'rsu'rfa''e 'of said flange hear" the periphery thereof, a 'contact intermediate the ehdsof said lean. a stationary 'contact carried hy said housing for cooperation with the 'movable Contact when the spring is exed, and'rneans depending fromv said harige teiigage the free end of the spring; and flex the sainel to" press said contacts together when the knob is patti-ally rotated in thev proper direct-ion.

4;- The' switch as defined in claim 3 including an overl Gente-i7 'spr-ing cooperating with said knob" to'liold it in either" of vtwo se'le'c'ied positions:

5. The switch as defined in claim-2t inwhich said knob ange i's fitted with a second depending tnean's to 'effect positive separation'of said eniaeis;

6. .In/ aiswitcli-fthe type describedyin combination; a-l-iollow; open-'topped housing; a c'veifor" said husiii'g having' aeeiiirai epehihjg ihere'ihreughi a kheb extending" through 'and jojrrialled inl said opening and having an axially disposed spindle jonrnalled in the bottoni of said hoisinga flange dise bri the knob engaging the nader surface of the cover, a laterally extendingarm on "said spindle, a spring 'compressed between said ini and a wall of the lio'usihg for overt-centerinoveinent as the knob is' oseillateti, a' leafA 'spring having 'one end fined adja'c'etrsa-id bottoni and extendingJtw/adnd v'v'itli'its free entljtist clearing the under vsurfaeof'said'disc near the periphery thereof, 'a Vstationary contal from' the hesing, a tact intermediate thefendsdf said leaf spring-and spp'rted thereby clear f but fr eeepeiatieiiwiih the siaiienaryeeiiiaei vandi-afi abutment depending Ifrom said disc to engage and flex the freeiid of the' spring'on'mb'veni'entof the knob' and thereby/'press ridhold the contats together' under the action f the overce'nter spring.

7.7Tiie' switch-pasdefined in cla'i 6 iii which sidi; ihe'ahsis provided for said knee te Vliiiit its iiidvh'iehi in contact opening direction.

8i The'switch as defined" in 'claim 7 iii-which the' stop mea-iis eeiiiprisee a d iipiieaie serl ijf-ined andv saiihg mounted contacts araiig'd't he closed by the' said abutment when the latter is-rnovd to' open the stcon"-1 tact set.-

9.\ T1-ie swiieh `as defined in en im s ih whiehsaid' lenen d isc'isfprovidedwithadditional a'bitments one spaced circumferentially on each side of the first topositively engage and move one spring in contact' opening direction as lthe otherismoved'in contact closing direction.l

lnThesWitghas dened ,inclaim Siri whieh ,thiwo gepiept, gamins Springs. are the. alms of a,U-Shaned.unit and a combined terminal and mountingplatesecured Vto thebase of said unit and pbfsit'i'oned in the bottoni of said h'ou's'irig'. a switch ofthetype described, in combination, bas a switch' operator'iricludin'g a knob a'se forfniariualos'c' positione betwee'irzsaid o' r be engaged by and resiliently limit movement of the operator in one direction, a contact carried by one of said leaf springs intermediate the ends thereof, and a stationary contact supported fre-m said base and engageable by said spring-carried contact under the urge of said over-center spring.

12. In a switch of the type described, in combination, a housing, a switch operator in the housing mounted for partial rotation about an axis normal to the front of the housing, a knob directly and rigidly connected to the operator and extending from the front of the housing, an over-center spring acting directly between the housing and operator to move the latter to a limit in either direction when moved past mid-position by said knob, a stationary contact rigidly mounted in said housing, a cantilever spring extending from the rear wall of said housing and having a free end positioned for engagement by said operator for movement thereby, and a contact intermediate the ends of the cantilever spring for electrical engagement with the stationary contact, said operator when moved in'one direction by its spring advancing said contacts toward each other and vice versa, engagement of said contacts serving to limit operator movement in one direction.

13. The switch as defined in claim 12 in which the cantilever spring biases the contacts apart and means on said operator to engage the cantilever spring to positively separate the contacts when the operator is moved for that purpose.

14. The switch as defined in claim 12 in which said operator and said housing are fitted with cooperating stop means to limit operator movement in the direction opposite from the contact engaging one.

l5. The switch as defined in claim 12 wherein duplicate cantilever springs, movable and stationary contacts are provided and the switch operator is provided with off-center projections for each cantilever spring, each adapted to engage an opposite side of said free end of the corresponding cantilever spring to move its contact in opening or closing directions, said projections being spaced apart so that in either rest position of the operator each spring is spaced from one of its operating projections such a distance that it is not engaged thereby until the switch operator is moved at least to mid-position.

16. In a switch of the type described, in combination, a hollow housing substantially rectangular in cross-section, a terminal plate at one end wall having an integral strap lying along the bottom of said housing and offset to one side thereof, a U-shaped spring having its bottom secured to said strap with the free cantilever arms of the U extending alongside one side wall of the housing and substantially parallel to the end walls, a switch operator oscillatable on an axis through the centers of the housing top and bottom walls and including a nger knob projecting above the top wall, a Contact button on an intermediate portion of one of said spring arms and facing the adjacent outer wall, a second terminal plate at an end Wall of the housing, a rigid arm on said last mentioned plate, a contact button on said arm in confronting but separated relation to the spring mounted button, means on said operator to engage the free end of said one arm and ex it to bring the contacts together, and overcenter spring means arranged to hold the operator 1n either one of contact engaging or releasing positions.

17. In a slow-break switch, in combination, a housing, terminal plates recessed in and carried by the end walls of said housing, a contact rigidly supported by one of said plates, a second contact spaced from the first, a cantilever spring blade supported at one end by the other plate and carrying the second contact intermediate its ends, a turn knob journalled in the housing on an axis substantially parallel to the said blade and overlying the free end of the blade, an eccentric projection depending from the undersurface of said knob positioned to flex the blade and engage the contacts and over-center means within the housing connected to urge the knob toward or from contact closing position.

18. A slow-break A. C. switch of the type including a stationary contact, a confronting movable contact, a cantilever spring fixed at one end, having a free end and supporting said movable contact at such a position intermediate the spring length as to provide low vibration amplitude when the free end of the spring is engaged to move the contacts together, a switch operator including a finger knob and a shaft coaxial thereto, means mounting said assembly for oscillation about its longitudinal axis positioned parallel to the longitudinal axis of the spring, over-center means urging said operator toward an end of its oscillation stroke and means on said operator to alternatively engage one or the other side of said free end of said spring to flex the same toward or away from contact engagement.

19. A slow-break A. C. switch of the type including a stationary contact, a confronting movable contact, a cantilever spring fixed at one end and supporting said movable contact for movement therewith, a switch operator including a finger twist knob and a shaft coaxial thereto and positioned with its longitudinal axis substan` tially parallel to said spring, means mounting said assembly for oscillation about its said axis, over-center means urging said operator alternately toward one end of its oscillation stroke and means eccentrically disposed on the undersurface of said knob to alternatively engage one or the other side of said spring to flex the same toward or away from contact engagement.

20. The switch structure of claim 19 in which the switch operator stroke is normally limited in one direction by the engagement of the contacts.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,200,847 Kaisling Oct. 10, 1916 1,531,347 Rhodes Mar. 31, 1925 1,963,722 Smith June 19, 1934 2,118,528 Scott May 24, 1938 2,254,509 Bassett, Jr. Sept. 2, 194i 2,301,704 Kempton Nov. 10, 1942 2,314,465 Shaw Mar. 23, 1943 2,343,807 Schaefer Mar. 7, 1944 2,583,756 Wahlberg Jan. 29, 1952 FOREIGN PATENTS Number Country Date 841,630 France May 24, 1939

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