US2689289A - Intermittently operating switching device - Google Patents

Description

Sept. 14, 1954 J. BELL INTERMITTENTLY OPERATING SWITCHING DEVICE 3 Sheets-Sheet 1 Filed Feb. 13, 1953 INVENTOR JOSEPH 5544,

BY i

ATTORNEY J. BELL Sept. 14, 1954 INTERMITTENTLY OPERATING SWITCHING DEVICE 3 Sheets-Sheet 2 Filed Feb. 15, 1953 3 5 I: aa .91 u E INVENTOR 1055/ /9 BELL;

ATTORNEY Sept. 14, 1954 J. BELL 2,689,289

INTERMITTENTLY OPERATING SWITCHING DEVICE Filed Feb. 15, 1953 s Sheets-Sheet 5 75 75 75 IM EXTQR 6a J0P4 5544,

ATTOR .\E Y

Patented Sept. 14, 1954 INTERMITTENTLY OPERATING SWITCHING DEVICE Joseph Bell, Orlando, Fla. Application February 13, 1953, Serial No. 336,713

19 Claims.

This application is a continuation-in-part of my application Serial No. 148,545, entitled Thermally Responsive Current Flow Changer, filed March 9, 1950, now abandoned, and of my application Serial No. 177,059, entitled Electric Current Intensity Changer, filed August 1, 1950, now abandoned.

My invention relates to intermittently operating switching devices, and more particularly to devices which comprise an expansible element and which are particularly adapted to signal systerns.

A general object of my invention is to provide an improved intermittently operating switching device.

Specific objects of my invention are to increase the reliability, simplicity and life of intermittently operating switching devices, to decrease the number of parts required, and to provide simple original adjustments or settings of the time cycle in such devices.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a side elevation of a device in accord with the preferred embodiment of my invention;

Fig. 2 is an end elevation of the device of Fig. 1;

Fig. 3 is a side elevation of the device taken from the side opposite that shown in Fig. 1;

Fig. 4 is an end elevation of the device taken from the end opposite that shown in Fig. 2;

Fig. 5 is a reduced perspective view of the device of Figs. 1-4;

Fig. 6 is a top view of the device of Figs. 14;

Fig. 7 is a schematic representation of portions of the device as incorporated in a direction signailing system for automotive vehicles;

Fig. 8 is an enlarged detail side view of a portion of the device of Figs. l-4 representing the position of certain parts of the device when the switching contacts are in open position;

Fig. 9 is a similar detail side view of the parts shown in Fig. 8 taken when the contacts are in closed position.

Fig. 10 is a detail side view on the same scale as Figs. 1-4 of a portion of the device showing the contacts in closed position;

Fig. 11 is a top view of a device of modified construction in accord with my invention;

Figs. 12, 13, 14, 15 and 16 are plan views of blanks prior to forming and assembly into the modified device of Fig. 11; and

Fig. 17 is a schematic representation of portions of the modified device of Fig. 11 as incorporated in a direction signalling system for automotive vehicles.

As seen in Fig. 1 the preferred embodiment of my invention comprises an insulating base member I, to which is mounted an upstanding post 2 carrying at its upper end a pivot or fulcrum'portion 3. An arm or lever member A is pivotally supported by the fulcrum portion 3' and is arranged to swing back and forth in accord with respective contractions and expansions of a thermal wire 5, which comprises an electrically conductive thermally expansible operating element. Wire 5 is soldered or otherwise mechanically affixed to a bendably adjustable support or anchor member I5 attached to base I by means of bolt 1. The upper end of wire 5 is soldered or similarly affixed to a protruding head portion 8 of arm 4. As seen in Fig. 1, head portion 8 and anchor member 6 are preferably curved at the portions in contact with the wire to reduce fatigue failures of the wire at its connected ends.

Circumscribing the extending lower portion 9 of arm 4 is a tension spring II). The upper loop of this coil spring engages a notch I I in the lever arm 4, and the lower end of the spring extends beyond the lower end of the lever and engages a movable contact member I2. Member I2 carries a contact button I3 at its upper end, which is adapted to make contact with one side of a contact button I4 carried at the upper end of a resilient contact member I5. The operation of the device is such that relaxation or expansion of the wire 5 permits the lower end of arm 4 to move to the right, as seen in Fig. 1, to oscillate contact member l2 on its pivotal support I ii in the direction to move button I3 into contact with button I4. When this occurs, contact element l5 bends toward the left and button I4 makes contact with button I? of contact member I8. A resistance element 1 9 connects between the conductive support member I5 at the lower end of the active expansible element 5 and an electrical terminal 20. The resistance element I 9 preferably comprises a loosely coiled continuous extended portion of wire 5.

Turning now to Fig. 2, the upstanding post 2 is seen to comprise a foot portion 2! bolted to base I and a lower arm portion 22 which serves to provide the notched pivot I6 in which a knife edge 23 of contact member I2 engages. The

.shown in reduced scale 1 in s Fig. 5. attachmentof post2 to base lby'means of foot 2| movable contact member I2 comprises a. generally U-shaped, thin, metal member having an upstanding contact-button-carrying portion and an opposite upstanding stop-engaging portion 24. Knife edge 23 extends inwardly from the contactbutton-carrying portion, and a similar knife edge 25 extends inwardly from the stop-engaging portion 24 to seat in downwardly opening pivot notch formed in the'post'2.

A stopmember'26 extends from the post2 to be engaged by portion 24 of contact member l2 when the movable contact I2 is oscillated into open position. Oscillations of contactmember .l2.result from motions of lever member '4, and these motions are transmitted through tension spring H] to the spring connection with member 'ilt'at aperture 21. As seen in Figs. .1.and.2, thelower end of spring I is formed into ahook portion 23 which engages in aperture 2? of member :12 below the pivot axis established through knife edges-Bend 25.. .As seen .in Fig. 2, the pivot or .fulcrum portion oomprisesan upper tab bent at right angles to the-bodyof .post.2.and.compnising .a notch in whicharm. 4 .is. disposed. .By' comparingthe views. ofFigs. .1 and.2,..it will be seen that Llever .4 may .be .positioned on pivot portion .3 by inserting the pivot portion into aperture .29. The area at the .bottom of the notch .in pivot :portion '3 .may .he knife edged .to provide .a minimum of frictionin theswingingof arm 4.

.As .seen.in.Fig..3, stop .26 extends downwardly along .a. substantial portion of post 2 .andis.engaged by portion. .of contact member t2. ,Memher '26 .is preferably of .a ..resilient..metal which,

however, is .readily deformed, .as' .by pliers,..into

a desired adjustedpositionat the timeoffabrication .of the device, .or. .during tests. When .the switch .is .in-the open position, stop =23 resiliently .urgesportion..2i4itowardthe right, as seen in Fig.3, althoughmemberdli is insufficiently resilient appreciably .to.follow ,portionlllasmember. l2 oscillates into the .switch closing position. Original adjustments of the timing cycle ofthedevice are .accomplishednot only .by bendingmember 25.to .liniitmotion of .portionI24-at .thedesired. position, but also 'by bending anchor member .6- to- .wardoraway from base II,..as necessaryproperly to tension expansible elementi.

Fig. 3 .further discloses the pivotal support notch'3 0 which .is formed. in. the body of ,post '2..and

in which isengaged .the.knife edge 'hereinabove identified by the numeral 25.

Fig. l'is an endview of .the deviceot .1-3.

Fig. '4 .shows .further. details of the shape .and

arrangement of the several parts .of .the .device.

-For example the .U Shapeofcontachmember [2 clearly portrayed and. the arrangement ofthe upstanding stop-engaging portion 124 and-of .the upstanding contact-button-carrying. portion .3!

are readily apparent. Anchor .member .6 is. seen tov comprise .a curved portion .towhich expansible element Sisafilxed.

Portions of the. device ass'hown in themfour views of. Figs. 1-4.1have been similarly numbered in each instance .to assist in .a clear understanding of theconstruction, although, forthe sake of brevity, specific. descriptions in connection with eachfigure arenot repeated. :It will be under- ;stood; that the description of .parts of the device most clearly seen in one of the figures is equally :applicable .to .the. similarly identified .parts as. seen in each .of the .other figures.

.A perspective view-of the device of Figs. 1-4 is The method of and bolt 32 is readily apparent, and it will be noted that stationary contact member I8 is similarly attached to base I by means of bolt 33. The bolts 32 and 33 additionally serve to provide electrical connections below base I to the respective conductive members supported thereby. The view of Fig. 5 also discloses the relative arrangement of expansible element 5, anchor member 8, contact merriberwlZ, resiiientcorttact member l5, spring l0 and lever member' l.

The top view of Fig. 6 specifically discloses the shape and arrangement of fulcrum portion 3 of ,post-2.in.connection with arm 4, and also shows .the general shape of the pivotal support portion 16'. The bottom end of post 2 extends into foot :21, and-the post is held to the base by means of electrically conductive bolt 32. Electrically conductive bolt'33'is seen to be arranged similarly to support contact member l8, and a bolt 34 mounts terminal lug 25 for resstance element I9 to the base il andfurther serves to mount resilient contact member -I 5- to the base by-meansof .a' horizontallower foot. portion .35 of member which extends along .the uppersurface of the base. and under lug 20..

.Fig. 7 is a schematicdiagram includingmartialiy fragmentary representations of .portionsof the switching device hereinabove. disclosed demonstrating the incorporation .of the device in an :automobile directionsignallingsystem or the like. .The conductive post .2 is connected tothe ungrounded terminal of the automobile'battery '36, to the movable contactmember t2 and. through the headportione ofarm. 4, .to the. upper end of expansible element 5. The lower end of expansible element oonnected through resistance element is to intermediate resilientv contact .memberliand toblade 31 ofamanually operable direction signalling switch. .Signal lamps 38, 39 are connected in parallel .to one switch .point 40 of the signalling switch, while lamps 4|, 42 are connectedto a secondswitch point '43. A central insulatedswitch. point 4.4 is provided atthe off position of thesignalling switch. Lamps. and 39-. may be mounted respectively at the .forward andrearward ends of the vehicle and ononeside thereof whilelamps .41 and 42 .are similarly arranged on the other side. A dash-mounted pilot lamp 45 ispreferably included in the system and is connected to stationary contact member ll! of =the device. Each lamp is returned to. the

grounded battery terminal.

Operation of the system to signal a turn inone .or the other direction .is initiated by. moving switch blade 31 fromits normal off position at point 44 to point 4ll..or .43- as appropriate. .;Assuming that the blade has-been moved to point an, .as. shown, current .from the battery :36 flows through post 2 and wire '5 in series, ,thence through resistance element l9, .blade 31 and switchpoint 40 and through lamps 38, 3.3, in ,parallel back to the grounded battery terminal. The resistance .of elements 5 and I9 is such that lamps 3B, .39 receivedinsufiicient energy to'be illuminated .to full brilliance and they may remain substantially completely dark. The current through wire '5, however, is sufiicient to heat the wire in a .short period of time, suchasone- .quarter .or one-half second, to a temperature at which the wire will undergo a change in itsilength dimension in thedirection or sense corresponding toan extension of the wire. A very small amount of elongation of wire .5 will resultin snap-actuationof movable'contactmember l2..into contact withmember I 5, and. member I 5 .is thereby resiliently swayed into contact withmember l8. Contact between buttons I3 and I4, of members I2 and'I5, respectivelyyprovides a short circuit for the elements 5 and I9 and supplies the full battery voltage to lamps 38, 39. The further contact of button '54 with button ll of member is supplies the full'batte'ry voltage to pilot lamp 45.

pull arm 4 back toward its original position. The returning arm snaps movable member l2 into its original open-circuit position, thereby removing the shortcircuit around elements 5 and I9 and permitting button I4 to separate from button I? to extinguish pilot lamp 45. Current now flows through element '5 to initiate a new cycle.

The operation of the intermittently operating switching device in accord with my invention, when embodied in a signalling system or the like of the general type indicated in Fig. '7, maybe further understood from the detail views of Figs. 8 and 9, taken in connectionwith' the general operating principles explained above and the overall arrangement of the device described with reference to Figs. 1-5. Fig. 8 shows a small partof lever 4, including its extremelower end 46, together with the circumscribing lower portion of spring I I]. The spring is arranged with its lower hook portion 28 engaged in the above described aperture in movable contact member I2. Only the lower part 01' member I 2 below the pivot I6 is shown. It will be'seen that this lower part of member I 2 is bent or inclined slightly from the vertical when the contacts of the device are in open position with the wire 5 in cold condition in accord with Figs. 1, 3 and 7. The force of stressed tension spring IQ on the member I2 as applied by the hook portion 28 is in the direction of arrow H, and the force exerted by' the spring on lever 4 is opposite in direction to that of arrow 41. Ac 'cordingly, while the force on member I2 is slightly to the left of pivot I6, thereby to retain the lower portion of member I2 at the leftward limit of its swing and with the portion 24 of member l2in engagement with stop 26 as seen in Fig. 3, there'is a horizontal force component tending to urge or bias lever end 46 toward the right. The horizontal component .tending to move lever end 46 toward the right is counteracted by the cold, and therefore contracted, wire 5. Spring H3, being a tension spring, is stressed by stretching from its rest or zero tension condition when it is installed in the. switch device. It will be clear from this discussion that spring I operates as a return spring continuously urging lever A in the direction to provide continuous tension on wire and additionally as an over center operating spring for contact member Ij2.

The direction of the forces on the member I2 are altered upon relaxation or expansion of the wire 5 resulting from the heating of the wire, which may occur as described above in connection with Fig. '7. Upon such expansion or re laxation of the wire 5, the horizontal biasing force component of spring Ill on the lever swings end 46 toward the right, as viewed from the side shown in Figs. 1, 8 and 9. The swinging of lever end 46 toward the right changes the direction of the force applied to member l2 until'this'force is in a direction immediately to the right of pivot I6 and this force then results in the snapping of member I2 into the position of Fig. 9. The direction of spring force now applied to member I2 is indicated by arrow 48 and is seen to pass immediately to the right of pivot IE, but it will be noted that a horizontal biasing component tending to urge lever end 46 to the right still exists.

Member I2 in the position of Fig. 9 has caused the contact buttons to engage, and the now hot wire 5 starts to cool and contract. Aslight contraction of the wire 5 is suflicient to move lever end 46 from its Fig. 9 position far enough toward the left to snap member l2 back into theposition indicated in Fig. 8.

The double function of spring I0 will be apparent from the above discussion. As demonstrated, there is a continuously applied horizontal biasing force component from the spring tending to urge lever 4 in the direction to apply continuous tension to wire 5, and the spring I0 also serves to provide over-center or snap actuation to member I2. In the particular construction shown, spring I0 further functions to retain member I2 in position in its pivotal mounting arrangement. Oscillations of the member I2 are limited the opposite directions, respectively, bystop 25 and by contact members I5 and I8. Thus in the open contact condition, when wire 5 is'cold, portion 24 of member I2 will be in engagement with stop 26, as seen in Figs. 1-6. Stop 26, being resilient and being slightly bent back by the pressure of portion 24, provides a portion of the force necessary to move member I2 from its open contact position toward its closed contact position of Fig. 9. Since stop member 26 can ,bepermanently adjusted by bending with a pair of pliers, or the like, during manufacture or during final adjustments, it furnishes a convenient means for regulating the duration of the periodduring each cycle in-which the contacts are open and the wire 5 is being heated. The duration of the open con,- tact period is also dependent uponthe size, length, and resistance of wire 5, the resistance of, ele} ment I9, the tension force of spring I0, and the relation between the wire 5 and lever 4, this latter relation being adjustable by bending. anchor member 6 toward or away from base I. In practice, it has been found appropriate to providea wire 5 about one inch in length and comprising Nichrome of between about 0.007 and 0.012 inch in diameter if the device is to be used in automobiles with six volt batteries. The resistance element I9 may have a resistance about one to two times that of wire 5, and when used with lamps 38,35 of about 2| candlepower each, the device so constructed and arranged may be adjusted to have a cycle time of the order of one second or less. Persons skilled in the art will understand that too little total resistance in wire 5 and element I9 will permit sufficient current to pass to illuminate the lamps 38, 39 during the period in which the wire 5 is being heated, and such persons will further understand that the permissible tension of spring I0 is limited by the tensile strength of wire 5. It has also been found possible so to arrange and adjust the device, by providing a wire 5 of five-eighths inch length and of 12.6 mil diameter Nichrome,that no operation. occurs upon failure of one lamp 38 or 39 when switch blade 3'! engages contact point 40. In practice. accordingly, in the signalling system of Fig. 7, failure of one of the signal lamps is .-indicated to the operator by the absence of blinkingv of the pilot .lamp hi.

1 It-zwill be understood :that the'dimensions and proportions ainrlicated .above are exemplary only, and tint the dimensionseand adjustmentscan be :loleoted to adapt thedeviceforservioe :in anyo'l many diflerent systems.

- .Theoperation of the "device is further related to and efi'ected by the action of contact members A! and 48. As shownxin Fig. 10,.snappirrg of movable contact member it! intotheaclosed-con- .tact, hot; wire, position causes button 13 to engage button tL-and to sway or bend :resilient: contact member ii toward member lluntil button 14 mcetsbutton H; A wiping action-of'contactibutton l3 against button I4 is obtainedbythe silient bending oi-member t5. According to'the circuit oiiFig. .7, it will be noted that only pilot light.currentpossestrombutton M to button 111, appreciable "wiping of the contact between ,theoe-twobuttons may also be'obtained by making stationary contact l8 of slightly resilient material. Stationary .contact member .iil -serves as a stopto limit-themotion ofmovable contact member .42 .in ,-its :switch closing direction, as well as acontact for electrical connection through ,button t! to buttons 14 and Hi. The resilience of member .15 amists'i-n returning oscillable or-mov- .able contact member-I2 from the circuit closed ,positionlci' Big. -10 to-the open circuit position-ot the earlier described Figs. l-7. .Aemodifiededevice in accord with my "inventionisshownintop viewin :Fig. 11. -In this mod- .ifled construction, insulating :base member 9 carriesan-upstanding post member-50 having a. Iootportionii rigidly mounted by means of a clip 52 to the base. A lower arm -53 is formed integraiwithposttifl, and thelower armris shaped similarly .to arm.22 :of the preferred embodiment .to providers, bearing notchfor movable contact memberufihwhich, in turn, is shaped and arrangedllikecontact member I2 of-the-preferred embodiment. Contact member :54 comprises an upstanding stop-engaging portion .24 which cooperates .with afixed, though preferably slightly resilient, stop member 26, the-stop'member being carried Icy-post member .50. The arrangement corresponds .to the portion '24 and stop 26-0f the,preferred .embodiment, both in structure and function. Movable contact .member .54 further carries a contact button. which. cooperates with the contact button of intermediate resilient contact member .lifirandthisresilient contact member sways, as theswitchingdevice operates into closed circuit conditionagainst stationary contact member 51. The operation of contact members 154, 56, 51 .thuscorresponds to the operation of contact members l2, l5..and I8 of the first embodiment as describedabovelin connection with Fig. 10. The contactmemberifi differsin shape from member l of thepreferredembodiment, particularly in its foot portion, and Fig. 12.is a plan 'view of a blank for member .56. .As there seen, button 58 is aflixed near the upper end of aflat, resilient body portion 59, while a foot portion "is arranged to be bent at approximately a rightangle to the body portion. SlotsSl are cutintc opposite sides of the footportion 60, and theseslotsare arranged to receive ears of a clip which attaches the member 56 to the base 49. :Foot portion 60 extends into aterminal tab 62, which 'may'be bent upwardly from the foot, and to which a coiled resistance element may be soldered.

lm-illustrates is blank from :which the post ,50 is formed. Foot'portiontl of postllais m ctanged to .bebent' at a right: angle ito-the'upstanding stanchion rbody portion 68, and :slots 64 1am .provided in the root to-receive the 1681'! 111- a mounting clip. The foot extends :intoa support vor:anchor 650i the lower end or the thermalzoue pansible-olemerrt, land the anchor portion at the afoot may 'be bent upwardly 'a few degrees 11mm the flat mounting portionrot theioot.

Lower arm 53 extends from-one sideoi the post body portions to be bent at. thetwo told lines indicatedon the blank into a position to=dispom pivotal support notch 68 in spaced alignment with pivotalsupport notch ll, which is donned ,in the poet body 63. These notches l6 and 1. accordingly, align pivotally -.to support the movable contactmember '54 in the mannerdescribed for notches wand 30 and the contact-member +2 in the preferred embodiment. xAn upperleuor pivot or fulcrum portion -M-extends1romthe post bodyilandhas a notch-formed with-a horizontal knife edge pivotal, and the operating lever member, videntified by the 'numeral w'lllin Figs. L1 .and 1 7,,swings or pivots Lon-kniieedge ,pivot 69 tin the assembled device.

Stationary contact member 51 isshown .-in blank plan view iniFig. .14. Contact member W may be less resilient than contact member ll. but it is of similar configuration, comprisingo mounting foot portion ll having clipear-receiving slots 12. No terminalntab .is -.necessasy'ron member 5-1 since :electrioal connection-thereto]! made preferably through mounting-clip.

A mounting clip blank #52 sintable .for -ma,in afilxing post membertiflttorbase M is;shown.-in Fig. 15. The-clip eomprisesm. body portion!" adapted .to .lie. fiat against the undessideot ,base A9 anda pair of ears Jladaptcdto be bentupe- ,wardly along respective fold lines .15 to-extend through small. vertical apertures .intbebase Al and throughthe respective ear receivingslotsifl 01 .post member .50., The body {Portion extends into a @terminalrlug portion. 15,Whl0h will .be bent downwardly and .by means ,0! which electrical connection to the supported member .is conveniently made. After the clipds positioned withiits'ems 14 extending upwardly through the mentioned respective small -base apertures and through the ear 1 receiving slots of the imemberJto be'mounted, the upperendso! the clip-earmark bent or crimped inwardly, :along, respective ,i'old lines '11, to ,lieagainst the uppersurtacemtnthc Ioot portionoil the supportedmemberrigidlyto secure the member in position .and .to establish good electrical contact between the-.clip and member.

.A- clip in. accord with 'Fig... 15 is ,used mama foot portion SI of postmemberlll itoinsulatinl base 49, .and similar .or identical clips aroused in a similar mannertoattachioot of resilient contactmemher .ilandiootporthn H ofstationary contact member. .to -base The manner of mounting the postand. contact members by meansi ofclips as descrihedihasieconomic advantages, particularly in oasetoflarge scale manufacture. over the boltand nutmounting arrangements shown in .the ..flrst described embodiment .of this. invention.

The lever member llqot..thismodiflnationnt my invention .is .of insulating material, such plastic or pressed impregnated fiber, and comprises notched ofiset head portion .11, seeninsid: view in Fig. 17, which engages withond-carrics on attachmentmember 1cm aecordwith ltg. 16 The-attachmcntrmembcrcncommiocsaflatmml {9 member of: generally rectangular shape having a contact tab portion 19 and a central rectangular aperture 88.

As seen in Fig. 11, the post member 58 and contact members 56 and 51 are each affixed to the base 49 by means of clips 52 of which only the upper endsof the ears are visible lying against the respective foot portions. Lever member 18 is pivotally supported on fulcrum portion 58 of post member 58 for oscillations in response to expansions and contractions of thermal responsive wire 8|. The thermal wire is affixed, as by soldering, to the anchor portion.65 at its lower end and to the attachment member 18 at its upper end. The attachment member is shown engaged in notch 82 in the head portion 11 of lever member 18. A resistance element 83,

preferably in the form of' a loose coil of re-' sistance wire, isconnected between attachment member I8 and the lugx62 of resilient contact member 56. Helical tension spring 84 circumscribes the lower extending portion of lever 18, in the manner of the first embodiment of Figs. 1-10, connecting. at its top to the lever and at its bottom to movable contact 54. Lever 18, through spring 84, controls contact member 54 exactly in the manner hereinabove described in connection with Figs. 1-10 for lever 4, spring l8 and contact member l2. of the first described embodiment, spring 84, as before, functioning as a biasing or return spring for lever 10. to cause the lever to pivot as the tension of .wire 8| relaxes due to heating of the wire, and further functionas a snap action spring for contact member 54,,and still further functioning as the sole-coupling between the end of lever 10 and contact member 54 for operating the-contact member in response to oscillation of the lever. As before, contractionof wire 8|, due to cooling, pulls head 11 of ,lever '10 toward base 49 against the horizontal component of force of spring84 exerted continuously on thelower endof the lever. The lowerend of the lever, not shown in Fig. 11 but inaccord with end 48 of the lever member 4 of the first, embodiment, swings in the direction away from anchor 65 to open the contacts 55565'| in response to cooling and contraction of wire 8|. Elongation of wire 8| due to heating permits spring 84 to oscillate the lever to move its lower end toward anchor 65, and thus to snap member 54 into closed circuit position, correspondingto the closed circuit condition of the first embodiment as demonstrated in Fig. 10.

Fig. 17 discloses by fragmentary representations certainfurther detailsof the mechanical arrangement of themodified device of Fig. 11. The head portion 11 of lever member 18 is seen to comprise notch 82 offset from the pivot bearing of the lever on fulcrum portion 88 of the main support post, and attachment member 18 is disposed in notch 82. Thermal wire 8| is soldered, or otherwise attached, to attachment member 18, and resistance element 83 is electrically connected to wire 8| at this point.

y The lower end ofthermal wire 8| is soldered to anchor portion 65 which is bent upwardly from the foot. portion The foot portionis afiixed to base 49 beingclamped under the upper ends of ears 14 of the clip, of which the body portion l3 lies under and against the under surface of base49. V

In the exemplary circuit shown in Fig. 1'7, terminal lug I8 is connected through a suitable conductor to the-ungrounded, terminal of automobile battery 36', theopposite terminal of the-battery being grounded to the automobile frame. The post member, represented in Fig. 17 by foot portion 5| and anchor portion 85, completes a connection from the ungrounded battery terminal to the lower end of thermal wire 8| and, through the knife edge pivots, to movable contact member 54. Conductor will be understood to represent the connection from the foot 5| through the body portion 83 of conductive post member 58 to the notches 86 and El in which movable contact member 54 is carried, as shown in other views, and through the electrical contact thus established at the notches 86 and 61 to contact member 54.

Resilient contact member 56 is connected at its lug portion 52 to the lower end of coiled resistance element 83 and through its supporting clip through a suitable conductor 88 to a manually operated direction signal switch blade 8?. Stationary contact member 51 is connected to a pilot light 45. Switch blade 8? is movable from a central unconnected switch point 44' to one or the other of points 48' and 43' to control signal lamps, such as lamps 38', 39.

In operation, when blade 3'! is moved from point 44' to point 48, for example, a circuit is established from the battery 88 through anchor portion 85 to the lower end of thermal wire 8|. The current flows through the wire 8|, heating and expanding the wire, and through resistance element 83 and conductor 88 to the lamps 38' and 39, and thence through ground to the other battery terminal. Upon heating of wire 8|, the device operates to snap contact member 54 against resilient member 58, and to sway member 58 against stationary contact 5?. Pilot lamp 45' is thus connected through contact members 57, 58, 54 to foot 5|, and lamps 88, 89' are connected to receive current from foot 5| through contact members 54 and 56. The current intensity to lamps 38', 39 is substantially greater with contacts 54, 58 closed and with the wire 8| and resistor 83 short circuited or shunted by these contacts. Since no appreciable current flows in wire 8| while contacts 54, 58 are closed, the wire cools and changes dimensions in the contracting sense or direction, resulting in the operation of the lever member against the horizontal bias of spring 84 into the position at which the movable contact member 54 snaps into the open circuit position. With the contacts now open, pilot lamp 45 is extinguished, and the current to lamps 38, 39 is so reduced by the series connection of wire 8| and resistance element 83 that these lamps are dimmed or nearly extinguished. The cycle may now start again as wire 8| is once more heated, and the operating cycles continue so long as switch blade 37 remains in contact with one or the other of contact points 48', 43.

The contruction of the device in accord with Figs. 11-17 permits ready assembly in that, following clipping of stanchion 58 and contact members 58, 51 to base 48, lever 18, spring 84 and movable member 54 may be mounted without interference from expansible wire 8!, and wire 8| and resistor 83 may be soldered to yoke 18 prior to installation of the wire, resistor and yoke in the device. When the lever 18, spring 84 and member 54 are in place, resistor 88 may be soldered to its lug 82 on contact member 56, yoke 18 may he slipped on protrusion ll of lever 18, and wire 8| may finally be soldered to portion 65 of foot 5|. The final tension adjustment is made by bending portion 65 downwardly, and this final tensioning of the wire will swing yoke 18 from its vertical position of Fig- 17, for example, into alignment II with the taut wire 81'. Resistor 83 exerts no appreciable force on yoke 18.

If it is desired later to disassemble the device, yoke 18 may be removed from lever 10, either by bending 65 slightly upwardly again, or by swinging lever 10 in the direction to drop portion 11', which may require prior removal of member 54 from its bearing notches 66-, 61 to relax spring 84.

While I have shown and described only certain preferred embodiments of my invention by way of illustration, many modifications will occur to those skilled in the art, and I therefore wish to have it understood that I intend,.in the appended claims, to cover all such modifications as fall within the true spirit and scope of my invention.

What I: claim as new and desire to secure by Letters Patent of the United States is:

1. A thermal expansible wire switch device comprising, an oscillable lever, a thermal wire connected to swingv said lever in one direction in response to contraction of said wire, a stressed return spring. afilxed atone end to said lever conv tinuously urging said lever in the opposite direotinnto tension said wire; a movable contact member,.pivotal= support andstop means for said memher suppflrting said member for limited pivotal oscillation about a pivot axis,. the other end of said spring being connected to said member at a pointspaced. from said pivot axis and effective in response to lever oscillation tooscillate said member .ovcr. center between limit positions established by: said stop means.

2-. In an intermittently operating switching device, apivotally mounted movable contactmember, stop and electrical contact means engageable by said member establishing a first limit position for said: movable member in a predetermined direction and a second limit position in the opposite direction, saidlmeans comprising electrical circuit means respectively opened and closed in accord with the pivotal position of saidmember in respect to one of said limit positions, a spring having. an and connected: tosaid member for snap actuation of said: member between said respective limit positions, said springbeing effective nor-,

mally' to retain said member in said first limit position, a pivotal lever engaging and laterally displacingv a portion between the ends of said spring, a thermal-electric element operative to force said lever against said spring in a direction. to increase said displacement in response to a predetermined dimensional change of said element, said spring being effective to return said, lever upon reversal of said predetermined dimensional change and resumption by said element of its originaldimension, said element being connected. for control by said electric circuit means.

3. A switching device comprising a mounting member, an arm swingably mounted to a predetermined part of said member, a switch member pivotally attached to said mounting member remote: from said part, a spring attached to said arm between the ends of said am, said arm terminating in a swingable end adjacent said switch member, said end being in contact with a portion between the ends of said spring, said spring extending beyond said arm and being terminally attached to said switch member beyond said pivotal. attachment thereof to said mounting member, stop and switch means co operating with said switch member to limit said switchmember to a predetermined are between substantially fixed limits and to establish an electrical connection at a first said limit of said are and. to open said electrical connection at the 12 second limiter. said' am',; a themm cleotric respcnsiuaetcment electrically. connected: to said! means for electrical energization undss' thecon'w trol of said cicctrical connection; said element being mechanically afixed mrceabiy: .to swingt said swingableend 01f said arm ezainst thc fome' or said. spring when said switch member. in at one or said limits of amtomnve said; portion. of: said spring. into position pivotally'to' snap sdidl switcbvmemberzte mc othoo one of saddlimdts'flii electric emansibie element memmcally eonnected to sarld lever to force sold lever-to pivot ina predetermined directicnin response to a thermalchange-in a dimension of said expansibi'c element in a predetermined sense, a-spnng em gaging'and urging said lever to pivot-in thedi rection opposite to said predetermined direction andeflecifive to-pivot-saidlever in said oppositedirection upon reduction cream lorce in response to a thermar change" in said dimension in the opposite sense, said spring being connected to said" movabie member to snap said movable member alternately from one to the other of said limit positions in response to rcspcctivepivotlng' of solid lever in said directions, electric switch centactmean controlled by said movabl'e member connected to saidexpansibl'c ele- HIGH);

5. Ina device of the kind described, apivotal contact member, athermo-clectflc cxpansibie wire element, actuating means for" pivoting said member in response to alternate contraction and expansion 0! said clement, said means comm-ming alewcr connected to said element and a; lever" biasing spring, said element and spring befna aiternateiyeflcctivcto swing said lever in respectire opposite-directions in accord with respective alternate expansion and contraction of said elemeat, said contact member beinsmechanicaily connected piv'otallytc respond to said. swinging of said lever; and: a resilient contact member contacted and swayed by engagement of said pivotal" contact member, said resilient contact member being, in circuit with said element to control elcctricactuatibn thereof.

6% In a deviccc! the kinddescribed; an oscillabi'c contactor, a second contacton a resilient contactor interposed between said osciliable contactor and said second contactor',.means comprising electro-thermally responsive actuation: means, to: oscillate said oscill'able .contactor to sway said resilient contactor into contact against said second contact'or and to return said oscfllable' contactor to break said contact between said resilient contactor and second 'contactor and thereafter to part said oscillab'le .contactor from said resilient contact'or, saidactuating mean being connected for electrical. actuation teat least-one of said contactors.

'7. In a device of the kind described, at least three circuit opening and closi'ngcontactors, a thermoheiectric remnsivcelement to-change dimensionaliy in response to changes in current therettn'outlna spring; oncolsaid ccntactors being pivotally mounted and connected to said spring for snap actuation thereby in two respectively opposite directions, two motion limiting stops for said one contactor respectively to limit said actuation to predetermined limit positions in each said direction, one of said stops comprising a second said contactor, a third said contactor being resilient and being disposed between said one stop and said one contactor to be out of contact with said one stop and said one contactor when said one contactor is against said other stop and to be hammered and pressed into contact between said one contactor and said one stop when said one contactor is actuated toward said one stop, means comprising said third contactor to supply a variable current to said element, and means operative through said spring to snap said one contactor in said directions responsive to predetermined respective dimensional changes of said element.

8. In a device of the kind described, at least three circuit opening and closing contactors, a thermo-electric responsive element to change dimensionally in response to changes in current therethrough, a tension spring, one of said contactors being pivotally mounted and connected to said spring for snap actuation thereby in two respectively opposite directions, two motion limiting stop for said one contactor respectively to limit said actuation to predetermined limit positions in each said direction, one of said stops comprising a second said contactor, a third said contactor being resilient and being disposed between said one stop and, said one contactor to be out of contact with said one stop and said one contactor when said one contactor is against said other stop and to be hammered and pressed into contact between said one contactor and said one stop when said one contactor is actuated toward said one stop, means comprising said third contactor to supply a variable current to said element, and means operative through said spring to snap said one contactor in said directions responsive to predetermined respective dimensional changes of said element and to exert a bia from said spring on said element tending continuously to oppose said dimensional change in a predetermined sense.

9. A switching device comprising a pivot, a contactor oscillable on said pivot, stop means to limit oscillation of said contactor in a respective first direction and a second opposite direction, a spring connected to said contactor at a point removed from the axis of saidpivot, a thermoelectric element, a lever mechanically connected to said element to be moved in response to expansion and contraction of said element in respectively opposite directions, said spring being coupled to said lever for movement thereby to snap said contactor against said stop means in said first direction in response to expansion of said element and against said stop means in said second direction in response to contraction of said element, and resilient contact member between said contactor and one of said stop means, said member being out of contact with said contactor and said one stop means when said contactor is toward said other stop means and being defiectable by said contactor into contact with said one stop means, said resilient contact member being adapted to supply an electric current of variable intensity to said thermoelectric element.

10. A switching device comprising a base, an arm swingably mounted toa predetermined part of said base, a switch actuating member pivotally attached to said base remote from said part, a spring attached to said arm between the ends of said arm, said arm terminating in a swingable end adjacent said member, said end being in contact with a portion between the ends of said spring, said spring extending beyond said arm and being terminally attached to said member beyond said pivotal attachment thereof to said base, stop means to limit said member to a predetermined arc and comprising switch means operative in response to pivoting of said member to one limit of said are, a thermo-electric responsive element electrically connected to said switch means for control thereby and mechanically connected forceably to swing said swingable end of said arm against the force of said spring when said member is at one said limit to move said portion of said spring into position pivotally to snap said member to the other said limit and operable when said member is in said other limit position to relax its said arm swinging force whereby said spring portion moves said end of said arm toward a position in which said spring snaps said member in the opposite direction again to actuate said element to swing said end of said= arm against said force of said spring.

11. A switching device comprising a support, an arm swingably supported by said support adjacent one end of said arm, a tension spring surrounding said arm and attached thereto between said support and the other end of said arm and extending beyond said other end, thermally responsive expansible means mechanically coupled member to limit said member in both directions of pivoting thereof, said other end of said arm engaging said spring between the ends thereof to snap said member on said pivot between said stop means and continuously to bias said other end of said arm against said force of said expansible means, said stop means comprising switch means adapted to control the temperature of said expansible means, said switch means being so oriented in respect to said expansible means that said expansible means moves said other end of said arm against said bias to snap said member in a predetermined one of said opposite directions and relaxes to permit said spring to move said other end and snap return said member in the other of said opposite directions.

12. In an automatic flashing switch, the combination of a pivoted lever member, a biasing spring attached at one end to said lever member and circumscribing said member and biasing said 1*5 andmircnmm'ibingrsaid: lever. and extending: beyomizsaidiend; .a themno-electxic elemaentconnect ed: in said lever, 'azmovable memben pivotailv sup pcntcdiontsaidhbaselandtattached truths-extending anchor: said spring saidzlever; being' arrangod pivoting tcrswing s said lever endi in: one direction imresponserto force exerted: by said element; sa'id mar-bk member being: positionedto disposee said spun; end z-outofi lineiwith saidilever inthe-otinerdirectionwihereby the-:tension oi 'saidispring pro-- vhino: a restoring; force operative in response to relamtbmsot: said: element: towswii'igv said endin sdldtntherr direction, means icooperating with saidmovable member'torcstrictsaid memberto pivot aliinmtion'; between substantially fixedillmitsszndi eledzxioailyrtoi control said element, the directim ofithe force applied: by' said spring to said movable-membranes efiected by the positionof saidilbvenendbeingsorelated to the position of; the pivot; for. saidmcvable member that said movableimember snaps, alternately." from one i to thmotherrotnits saidslimits in rcsponsetoalter mate swinging: of." said lever end in said one and saidkother directions.

4411A]! intermittently operating switch. device cumming an insulating base, i a conductive stanchion mounted on: said base; anz insulating levies-member pivotallyvsupported: on said base by said stanchion; a conductive movable con-- tact'memberpivotally supported on said base by midi stanchion; contact means ,1 electrically conmating: with said contact member in. response to swinging'ot said' oontactmemberto:=a predatormined position, a thermo-el'ectric.expansible elemcntmloctxioally and mechanically attached at one end: to said stanchion and operatively aflixed tonid levermember at 'theother end forceablyvto swing soidlever memben in a predeterminoddircw tionin response tora/ predeterminedi dimensional change of 'saidelement, a permanent electrical, oonnection-betwecnsaid other endofsaid el'ement andisaidcontact means, a tensiclrsprin g mechanil oaily: connectingsaid lever member and movable contact it member and arranged to provide: snap. actuation of said: movable member alternately into and from; said predetermined position, said: spring and movable member being disposed tov provide a yielding spring biasing force against said lever member in a direction 'tending to opposs said forceableswinging'of saidlever member; =15; A device of the kind described comprising a basc', a movable contact member: pivota-llv supponted fromsaid base; means to-limitswmging of said-member in both directions and to close an electric circuit inresponse to swinging'of! said member to: one limit position, a lever'pivotally: supported from said base, athermo-el'ecizclc ele-- ment; connected to said: lever-to exert a force-to pivot said lever in" a predetermined direction in response to thormal actuation ofsaid element in: a" predetermined sense; a spring connected to: pivot said lever in the opposite. direction: upon reduction" of said force in response to thermal actuation of said' element in the opposite sense; saidspring being' posit/loned to be latoraily displaced in accord with the-pivoting or said lever, said spring being connected to said contact member'tor-snap actuation ofsaid member alternately between its said limit positions in responseto said spring'displacement's inrespectively opposite directions in accord with said pivoting of said lever, said circuit being connectedto said element for control thereof in accord witirthe position of said contact member:

16. In combination, a: base; a lever member pivotally supportod onisaidlbasosa tensicmspring attachedto said lever mcmbor remote irom: an end of said' lever: member and circumscrtblingssaid levermembcr at swifliend andamending beyond sa1d ond;;a snap acting movable 'cont'actpivotwllw supported for swinging motion on: said and-I attached" to the extending and 0t said spring, a thennowlecmc element connected to said lover member; means=to limit the swinging: motion of: said contact-sow to i close anvolectric circuitnat'a first-saidlimit and to oponsaid circuit: at tlic" sooondsaid" limit; said clement being co'nneotedi to said circuit for'eloctrmthennal actuation in: accordwitn ttie poistion': oi said contact with 1 respect to said first limit, saidelomentbeing utitanned iomeably" to: pivot said lever in imprecis termmed directiondaterallym detorm ssid sprinm inresponse to-positioning of 'said contact x atone oisaid limits; said movobib contact being're sponsive to said lateraldefomiationeto-snap-to tha otlier said limit thereby to reverse theactuation condition of said elemerm. said laterally deformed springooing effective to return said?- lever upon'rsl'astatlon of tho force otsaid elomeno insaid reversed"- antuation condition to a poshtion of 'reduoed' spring'dofomiation atwhich said contact snaps again tosaid onmlimita 17? An intemiittently operating: switch device compri'sing a swingable lover; a thermal expansi blewiwelement awaclied to said lever toswin'g said lever' in a predetermined" dlrection inJesponse tc-contraction of said wire;areturrrspring attached to said lever swingably to return ssid lever in the opposite direction in response to ex pension-of said element, said spring having a portiondisplaced in respectiveopposite directionscorresponding to the respective swing-= dlsplacemonts: of said lever, and a pivotat switch member for motion between two opposite limits; said member being attached to said: spring and responsive to predetermined r espective displaced" positions of said portion tc---snap over-- center alternately irom-oneto=the other said limit -in worm with said 'respeotive- -displaooments of said lever; sasicl wire being. connected for control of alternate expansion and contraction thereofi inaccord with said respective limit positions of said switch member.

18: In. a device of the kind-described; a tension spring; 'alever forminga core of said spring; a thermo-electric element attached to said lever in" response to a change in dimension-of" said as ment to swing said lever against the tension of said spring from' a first positionto' asecondposition, aportion' oi' said spring being deflected from one position to another -position-bv said lever motion from said first positionto said-1 second position; switch means operatively con nected to said spring for actuation from one to another position in responseto saiddeflection of saidspring' portion intcsaid other position; said switch means comprising means' to-ccntl'ol actuation of said element to reverse said" changeindimension in 'response to assumption of said other position by'said switch means; said-spring comprising a return spring for said leverand bei'ngeffective to: return saidlever as said reversed change in dimension occurs to saidfirst position therebytc-returnsaid switch means tosa-id one l sition.

19; In a snapacting switch, a pivotal switch member; an over centenspring-for" actuating said member from one to another position; anther-mal wire element, a lever connectedto said element fon'forced motion in a" predetermined direction- 17 in response to contraction of said element, said lever being connected to said spring to actuate said switch member alternately between said positions in response to swinging of said lever and to be return actuated by said spring in the direction opposite to said predetermined direction upon expansion of said element, and control means responsive to the alternate positions of said member alternately to decrease and increase References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Brogger Feb. 13, Schmidinger Nov. 6,

Horton Mar. 30,

Images