US2644899A - Flasher - Google Patents

Description

July 7,. 1 953 n. -s."P'ERRY 644.5899

Y FLASHER Filed July 29. 1939*- 2 Sheets-'Sheet 1 @L my 64 F/GZ .Elu 12 R. s. #ERRY July 7, 1953 FLSHER 2 sneetsneet z Fuga July 29, 1949v #M Tm TDM N N. R s o @fm /m PM Patented July 7, 1953 FIJASHER Robert S. Perry', Westfeld,..N. .J..',.. assignor; by

mesne assignments, to Perry'lilasherSyndicate;.v

Westfield; N. J.

Application July 29, 1949, Serial No`."107,497 l 1.6 Claims. l.

Thisinvention relates to an automatic switch or"asher for periodically makingand breaking an electric circuit.V It. isfoften desirable to intermittently operate orllash an incandescent lamp at short regular interval's'in order'to draw attention to'the'light. This is particularly desirable in certain advertisingfdisplays andy in warninglights. It is commonto provide automobiles with indicator lights to-warn` the drivers of other automobiles of inten'- tion to turn or stop. These lights are Ypreferably blinked or intermittently operated to attract greater attention.

Inl' the form.. shown, the present invention is applied to a asher for blinking the turn indicator lights of an automobile. The flasher unit comprises a stack of metallic'plates, a portion of one of which forms a movingswitch arm that is arrangedto be controlled by a hot wire. The switch, which is spring biased to closed position, is connected in shunt of the not wire; and the hot wire'is connected. in series with the light that istobe flashed. When the wire is cooly it holds the switch open, and the current which then passes isinsuiiicient to light the lampA but sucient..to. heat the wire. As the wire heats it lengthens, permitting the switch to close and shunt. out. the wire. The. current .i that then passes is sufhcient to light the lamp, and the lamp remains'lighted. until the hot wire has cooled sufciently'toopen the switch and thereby restorethe circuit to its initial condition. This cycle.is;then repeatedv again and again, so that they light. continues to blink; Thegiiasher shown may becombined with a relay for; operating a pilot light toindicatefthe operation'. of the lights controlled by the flasher. l

, A feature-sof the. present invention is that rapid closing and opening of the'. switch is secured solely by the interrelationship of. only two opposing moments,` the.: switch arms always being biased `towards closed position. rAnother feature ofthe invention is .that due to the'specic construction and arrangementmost .ofthe factors controlling the rduration of the. on and oli periodsmay be very closely controlled, final. adjustment being made during assembly solelyby thetensioning of the hot wire. The specific'confstruction permits a relatively largeamount of tolerancein this adjustment without adversely affecting operation of` the flasher.

An object of the present invention is .topfovide'an improved flasher that is durable, .sufficiently shockproof, easily assembled and adjusted,v4 and.` that will. retain its adjustment indeiintely.

Another object of.; the invention is toprovide anew and improved methodof .periodically interrupting: an: electric circuit.

Another object is to provide an improved flasher and relay combined in a single, unitary structuregthat lends: itself. to quick and easy assembly:

Another object is to generally improve flashers of the.. type described;

Further objects, and objects relating-to details and. economesrof manufacture, assembly and usa-.zwillmore denitely'appear from the detailed description to follow.

My; invention is'clearly denedin .the appended claims.r Where parts are, yfor clarity and `convenience., referred. to on the basis. of their oriented. position shown in the accompanying drawing, no limitation as to positioning of the entire structure isxto be implied.' since it will be understood that the entire structure may be in- Vertedfory that it` may be used in any inclined position. Also in both the description and the claims, parts at times may be identied by specificA names for clarity and convenience, but such nomenclature is to be understoodas having thefbroadestmeaning consistent with the context andw-ith the concept of my inventionas distinguished from the pertinent prior art. The bestiorm' in which I have contemplated applying my invention is illustrated in the accompanying `drawing forming `part of this specification, in which:

Figure. 1 is :a schematic diagram showing the flasher. ofthe-present invention applied tothe control of asingle lamp. K

Figure 2. is awiringxdiagram of the combined flasher and relay as applied toya Iturn signalling system of an automobile;

Figure 3 is an explodedisometric View of the combined ii-asher :and relay.

Figure 4.- is a top plan View of the plateof the v flasher that provides the switch arm and biasing is pivotally mounted at a pivot point I5. This spring engages against an end of the switch arm II, pressing lengthwise of the arm, the portion of the arm between the pivot I2 and the spring being rigid, A substantially rictionless knifeedge connection I6 (see also Fig. 6) between the arm and spring retains the spring in engagement with the switch arm, the arm and spring forming essentially a toggle. However, the knifeedge connection I6 always remains on the same side of the neutral axis through the pivot points I2 and I5, the abutment I1 serving to prevent the knife-edge connection I6 from crossing this axis. Thus, the spring I4 continuously biases the switch arm Il laterally in the same direction, i. e. toward closed position. The spring I4 is sufciently long so that there is no substantial change in length of the Spring as the switch arm II oscillates and the pressure of the spring on Y the switch arm is substantially constant.

A stationary contact I9 of the flasher is positioned to be engaged by a cooperating movable contact 26 mounted on the switch arm II adjacent the knife-edge connection I6, the flasher being in the on position when the contacts are L Wire 22 may be formed of the nickel-chromemanganese-iron alloy resistance wire `commonly known as Nichrome The length of the wire 22 is such that at atmospheric temperatures the wire 22 is under tension and exerts a pull on the end portion 2I of the switch arm II. This deflects the portion 2I of the switch arm somewhat and oscillates the switch arm against the abutment I1. The contacts I9 and 20 are now sepa-rated. As the temperature of the wire 22 increases, the wire lengthens somewhat due to expansion, lessening the moment on the switch arm I I and permitting the spring I4 to oscillate the switch arm in the opposite direction so as to close the contacts I9 and 20.

An electrical lead 25 is connected with the switch arm Il, and the contact I9 is connected directly to a lamp 26 by a conductor 21. The abutment end of the hot wire 22 is connected with the conductor 21 by a conductor 29. The arrangement is Such that when the iiasher is in normal or starting condition, the wire 22 is cold (i. e. at atmospheric temperature) and the contacts I9 and 20 are separated, the switch arm II resting against the abutment I1, and the end portion 2I of the switch arm being deiiected upward slightly due to pull of the wire 22.

Upon establishing an electrical circuit to the lead 25, as by manually closing switchv I3, the wire 22, which is of relatively high resistance and in series with lamp 26, will be heated by the passage' of electric current, although the current will be insunicient to light the lamp '26. As the temperature of the wire 22 increases, it lengthens somewhat and thus decreases the force or moment tending to hold the switch arm I I against the abutment I1. When the effect of the hot wire pull on switch arm II drops below the eiect of the biasing spring I4, the lspring I4 oscillates the switch arm with a snap action. This closes the contacts I9 and 20 and establishes a direct connection between the lead 25 and the lamp 25 to light the lamp, the flasher then being in the position indicated in Fig. l.

Inasmuch as the direct circuit through the contacts I9 and 20 is of very low resistance as compared with the circuit through wire 22, substantially all of the current passing through lamp 26 will pass through the direct circuit and the current passing through hot wire 22 will drop to substantially Zero. The wire 22 is of such small diameter that it cools quickly. As it cools, it shortens and increases the force or moment exerted by it on the switch arm II until it overpowers the moment caused by spring I4. At this point the contacts I9 and 20 are separated with a snap action and break the direct circuit to the lamp 26, whereupon the cycle will commence again. By varying the specific design of this flasher within the general construction and arrangement above set forth, the time interval of both the on and 01T periods of the lamp 26 may be accurately controlled or varied, as well as the time interval required for the entire cycle.

Increasing the air gap between the contacts when in off position or increasing the pressure of the spring I4, decreases the number of flashes per minute, the other factors remaining the same, while increasing wire tension increases the number of flashes per minute. An increase of voltage or any other factor that increases the rate at which the wire 22 heats and lengthens tends to increase the number of ashes per minute. For the ordinary signalling lamp a rate of about to flashes per minute is desirable, with the on period approximating the off period.

A feature of the construction shown diagrammatically in Fig. 1 is that as the wire 22 becomes heated and lengthens, the end portion 2l of the arm straightens and the wire 22 swings toward the pivot I2, thus decreasing the moment which the wire imposes on the switch arm II. When this moment falls below the opposite acting moment on the switch arm imposed by the spring I4 with the contacts fully opened, the switch arm oscillates to closed position. As the switch arm commences to move away from the axis of the pivots I2 and I5, the moment caused by spring I4 increases rapidly, the pressure being substantially constant and the lever arm rapidly increasing. At the same time, the counteracting moment imposed by the hot Wire is relatively constanty the end portion 2I of the switch arm being deflected slightly. Thus, the contacts close with a fast snap action.

`After the contacts I9 and 20 have closed, the wire 22 will commence to cool and shorten thus exerting a constantly increasing force on the resilient end portion 2I of the switch arm II. This force deflects the portion 2| of the arm upwardly, thereby storing energy in springy portion 2 I and creating a constantly increasing counteractinlgr moment tending to open the contacts. When this moment exceeds the moment of the spring I4, the contacts will open. As the contacts start to open, the lever arm at which spring I4 acts on the switch arm I I diminishes rapidly, thereby rapidly .diminishing the bias whichtends to close the contacts. Thus, the contacts snap open quickly, under the influence of the energy stored in springy portion 2I of the switch arm.

While the counteracting moments are substantially equal in each instance at the instant the movement of the switch arm II commences.- in

leaclrinstance 'the degree ci 'unbalancevery rapidlyincreases asthecontact 2-fmoves, thereby producing-faiveryrapidmake-or break of the con` tacts I 9- and Zliwith'out theinterplay of any force other than the forceof thehot wire 22 and the force of the biasing spring I4. y l I The il'asher previously described may beconstructed/ of a= stack; orfpile of steel plates that have been cadmium plated to prevent rusting. The plates have peripheral edge portions provided with holes-for reception of rivets` tof secure the assembly, theedgeportions of the plates collectively forming a-frame or housing `for the op'- eratingAV portions of the flasher; In describing the'plates and the assembly made therefrom', corresponding parts will bedesignated'by the same reference characters-usedein Fig. 1.

"Referencew-ll now be had to Figs: 4 and 5, which-show a two-part steel plate composed of parts vand .3i-which lie ina commonplane and meet end-to-end at 33. Metal is stamped out from part 3l? as shown-to havea centrally located projectingv spring Iwhich is the biasing spring I4" of-Fig.A 1'.r4 By means of overlapping kerfs 3l, 39land 31, 39 the metallic connection between spring I4 and the outer portion of part 30` is so reduced and arranged as to form (in effect) the-pivoted connection I5 (see also Fig. 1).

Metal is similarly stamped out from plate part 3I to form a portion of switch arm I I. By means of overlapping kerfs 32, 34 and 32, 34 themetallic connection between the arm I I and the outer por- AtionV of part 3I is reduced and arranged to form (in eiect) the pivoted connection I2 (see also Fig. l).

The end portion 2| of the switch arm I I, for receiving the hot wire 22, may be tapered from the pivot I2 so as to bend uniformly throughout its length under the pull of wire 22. A rigid strip 35 is secured to the remainder of the switch arm I I by-rivet 36 and provides a rigid arm from the pivot I2 to the knife-edge connection I6. The contact 2i! is formed of a strip of silver inlaid on one side of the strip 35 adjacent the knife-edge connection I8 (see also Fig, 6), the inlaid strip also forming one side of a slot receiving the free end of the spring I4 to form the knife-'edge connection. The portion 2| of the switch arm I I is 4laterally oiiset somewhat as indicated in'Fig. 4 to provide clearance for the hot wires'when both the iiasher'and relay are combined in a single structure, as in Fig. 3.

Referring now to Fig. 3, the entire stack of plates and parts'forming the iiasher and relay arev shown in exploded relation. plates are provided with registering marginal holes used to facilitate assemblyv of the flasher and to receive rivets or other fasteners for lsecuring the assembled plates.

A plus or line terminal plate 4I, which is positioned adjacent to the bottom of the stack of plates, is provided with a terminal 42 for receiving the wire 25 of theFig. l and is also provided with a bridge portion forming the abutment I'I that prevents the knife-edge connection itfrom passing below the axis of the pivots I2 and I5. The underside of the line terminal plate 4I is covered by a cover plate 44 to inclose the'bottom 'of the nasher unit. The inside ofthe cover plate may be insulated from plate 4I by a coating of lacquer.

- The next plateof the series comprises the two- Apart-plate 3Q, 3l of Fig. 4, this plateincluding the switch arm II- and spring I4.' Above this plate ris provided aspacer plate-45fwhich may be coated All of these 6 with-lacquer tov insulate 'it from the plate next above rThis plate: determines-the air' gapzzor spacing betweenthe contactsnl 9 .and 'ZU-Whenthe switch arm II is againstftheabutment II'."` Above the spacer plate-.a5, afplate 46 is providedwhich hasfa vbridgeporti'on forming the contact I9. `A

smallosilver contactbuttonl-m'ay be provided -on Y the bridge portion of the plate if desired.

The next succeeding: plate 41 is formedin two U-shapedfparts as indicatedv inFigr. dior-:convenience of assemblyof the'iiasher.v This-:plate is provided: at one end witha knurled portioniformze ing the/abutmentA 24 for receiving an end-ofthe hot vwire `i2 extending to ythe'switch armfII. For convenience-of attachment ofthe wire 22 to the portionZ I of theswitch'arm, it is desirableitouuse a-single wire having itsvmid portion looped'.l about theportion 2! ofthe switch armand the two `ends attachedfto the. abutment 254,- thetwo-branches of'v the` wires functioning together as asingle lengthV of hot wire. l

Thenext succeeding four plates, including: the spacer plates and'EI and which are similar to the spacer plate B5,- therelay terminal plate 50, and the two-part switch arm and spring plate-52, 54 needbe insertedonly when it is desired to have aA relayincorporatedin the iiasher unit'. The nature andiunction of these four plates will-be explained hereinafter. If thesefourvplatesare omitted; the load terminal plate- 43,-. which is identical to plate 4I but in invertedl position, may loe-mounted directly on plate 4l,A theterminall'48 of the plate [it receivingthewirel leading tol'- the lamp or lamps 2S to bey controll'edl A second cover plate 44, which ils-lacquered on'the inside, covers the top of plate 43.

With the relay plates omitted the current pass'- ing into the line terminal plate lil-is conducted into plate portion 3I= and switch arm I I, from whence the current passes upwardlythrougli the wire=22 and to the load terminal plate 153.' When the contacts i9 and 2c are closed by upward movement or the switch arm- II, the current passes directly from the switch arm II to the plate dt, theplate 4l and intotheplate '435m order to light the lamp.

' When the relay is incorporated in the flasher, it :may be connected into a circuit for indica-ting to'la person driving an automobile that the signal lamps are in operation. In a form shownof this invention, the flasher unit is designed to flash a lamp at both the front and rear of the car to indicate a vright or left turn. The relay is pro'- videcl to control a monitor circuit lighting a pilot light 551(Fig. 2) on the instrument panel of the automobile. I

The physical structure of the` relay switch-'is generally similar to that of `the flasher switch hereinbefore described. The switch arm `and spring plate portions 52 and 540i therelayv are identical` respectively with plate portions SI and lljiof the flasher but in inverted position. Below these plates, the spacerv plate 5i', which is insu?- latedfby lacquer on its top surface, serves to space the switch arm 53 from the relay terminal plate 5i), which is providedwith a bridge portion form.- ing acontact 5S for the switch'armof the relay. A spacer plate 49, which is insulated by lacquer on its top surface, separates the plate 5c from the abutment plate 4l.

A hot wire 5'I serves to operate theY relay," this wire being similarly arranged to the wire 22' but of much lower electrical resistance. In the flasher of the present invention as applied to 6 volt automobile electrical system; the-hot wire 22 may have an electrical resistance of about 2 ohms while the hot wire 51 may have a resistance of about one half ohm or less. The hot wire 51 is in series with hot wire 22, the latter wire being cyclically shunted by the closing of contacts I9, 20. When the signal lamps are lighted, the lampcurrent passes through wire 51, but is shunted around wire 22.

. A front signal lamp is in parallel with a rear signal lamp and, therefore, when both are operating, the current through hot wire 51 is twice as great as when one of these lamps has burned out. The action of the relay is such that when both the front and rear signal lamps of the automobile are operating, the wire 51 is heated sufiiciently to enable the relay switch arm 53 to engage the contact 56 of the relay terminal plate 50 to complete the circuit to the pilot light 55 (Fig. 2) while, if one or both of the lamps at the front and rear of the car are not operating, there will be insufficient current passing through the Wire 51 to cause it to heat and expand sufficiently to complete the circuit to the light 55.

Since the wire 51 is sufiiciently heavy it will not, once it has been heated, cool enough during the time that the direct circuit to the lamps is interrupted by the flasher to cause the relay circuit to the pilot light to be interrupted. However, when the direct circuit to the signal lamps is interrupted, the relatively large resistance of wire 22 is introduced into the circuit and this extinguishes the pilot lamp 55 the same as the signal lamps 26. Thus, the pilot lamp hashes when both signal lamps are flashing.

The construction of the flasher unit is particu* larly adapted for ease of assembly. The flasher is assembled on studs, not shown, the plates being individually stacked from bottom to top on studs passed through holes 59, 59 and 60, 6U in the bottom cover and the corresponding holes in the rest of the plates. By this arrangement, the switch arm plate part 3l may be inserted first and the spring plate part inserted later so as .to engage the end of spring I4 with the switch `arm l I to form the knife-edge connection I6.

The right end part of the abutment plate 41 is slipped in after the remainder of the plates have been assembled, this part of the plate 41 having a pair of open holes or slots to permit later insertion onto the studs.

After assembly of the flasher, rivets 6I (Fig. 2) may be inserted through the marginal holes to `hold the entire stack of plates in assembled relation, the rivets being temporarily omitted from lthe pair of holes at the right end of the asher. The rivets are insulated throughout their length to prevent electrical contact with the plates.

Small wedges, not shown, may be introduced :between the abutment end of abutment plate 41 and the next adjacent plates 46 and 49 to space these plates slightly until the wires 22 and 51 have been properly tensioned. After tensioning the wires to the predetermined tension for the flasher characteristics desired, the Wedges may be removed permitting the plates to come together and rigidly clamp the wires. The remaining rivets are then added to aid in holding the entire assembly.

The flasher of the present invention has a rigid case formed of the steel plates, which is not easily distorted. The moving parts are held to .a minimum and there are no fragile parts thus assuring dependability of operation and making lthe device resistant to physical shock and otherwise very durable.

The pivots I2 and I5 formed by the overlapping kerfs are easily formed and are durable. Also, the pivot l2 may deflect or raise somewhat under pull of the wire 22, forming in effect a somewhat resilient pivot andvpermitting greater tolerance in adjusting the tension of the wire.

The flasher may be incorporated in the circuit indicated in Fig. 2. In this circuit, the automobile battery 62 or other source of power is connected with the line terminal 42 of the flasher. A selector switch 64 of a well known type, which is customarily mounted on the steering column. is connected with the load terminal 48. The selector switch 64 may be operated to illuminate either the right-hand or the lefthand pairs of lamps 26 to indicate either a right turn or a left turn, it being understood that one lamp of each pair is on the front of the car while the other lamp of the same pair is on the rear of the car. The relay terminal plate 50 is connected with the pilot light 55 to indicate operation of both lights 26 of the selected pair.

The flasher and relay of the present invention does not include any electro-magnetic device, and hence is equally suitable for use with either direct or alternating current.

I claim:

l. The method of obtaining rapid acceleration for the opening and closing of the contacts of a ilasher for interrupting an electrical circuit at frequent regular intervals, the flasher having a contact arm mounted for pivotal movement and the arm being continuously biased towards closed position by a momentwhich varies between a maximum at closed position of the contacts and a minimum at fully open position, said method comprising: applying a counteracting moment to the arm and varying the counteracting moment to alternate it between values greater than the maximum and less than the minimum of the biasing moment, and storing the energy of the counteracting moment without any relative movement of the contacts until such time as the ccunteracting moment overcomes the biasing f moment.

2. The method of obtaining rapid acceleration for the opening and closing of the contacts of a flasher for interrupting an electrical circuit at frequent regular intervals, the ilasher having a contact arm mounted for pivotal movement and the arm being continuously biased towards closed position by a moment which varies between a maximum at closed position of the contacts and a minimum at fully open position, said method comprising: applying a counteracting moment to the arm while the contact arm is stationary, varying the counteracting moment to alternate it between values greater than the maximum and less than the minimum of the biasing moment, and restraining the contacts from any relative movement until the instant of separa-tion of the contacts.

3. The method of obtaining rapid acceleration for the opening and closing of the contacts of a flasher of the type in which a pivoted contact arm is continuously biased towards closed position and is periodically held in open position by an opposing moment of intermittently varying magnitude, said method comprising: arranging the opening land closing moments on the contact arm such that, upon both opening and closing movement of the contact arm, the difference between the moment causing the motion and the moment resisting the motion is rapidly increased as the initial movement of the contact arm takes V4. The ,method of obtaning rapid acceleration forthe openingand closing of the contacts of a :.ilasher ofthe .type in which a pivoted contact arm :is continuouslyrbiased towards one positionrand is periodically heldin another position by an opposing 'moment of intermittently varying magnitude, said method comprising: arranging the openingv andclosing moments on-the contact arm such that, zupon` both opening and closing movement of the contact arm, the difference between ,the moment causing the motion and the moment iiresisting the motion is rapidly increased as movement .of the Contact arm takes place, the contacts `being restrained from any relativemove- `ment until the instantY of their separation.

v5. The method of Vobtaining rapid acceleration the arm being continuously biased towards closed position by a single force causing a moment on the arm which varies between a maximum at closed position of the contacts and a minimum at fully open position, said method comprising: applying a single force causing a counteracting moment alternately varying between an amount greater than the maximum and less than the minimum of the first moment, the contacts being restrained from any relative movement until the instant of their separation.

. 6. The method of obtaining rapid acceleration for the opening and closing of the contacts of a flasher for interrupting an electrical circuit at frequent regular intervals, the asher having a contact arm mounted for pivotal movement between open and closed position and the arm being continuously biased towards one position by a moment varying between a maximum at the one position and a minimum at the other position of the arm, said method comprising: applying a counteracting moment to the arm and varying the counteracting moment to alternate it between an amount greater than the maximum and less than the minimum of the first moment, and storing the energy of the oounteracting moment without any relative movement of the contacts until such time as the counteracting moment overcomes the biasing moment.

"1. A flasher of the hot-wire type, comprising: a switch arm pivotally mounted between its ends, one end portion being substantially rigid and the other end portion being resilient, an electrical contact in the path of movement of the switch arm, a spring biasing the switch arm at constantly increasing moment as it approaches the contact, and a tensioned wire intermittently heated by passage of electric current and having one end anchored and the other end attached to the resilient end portion of the switch arm for supplying a moment acting counter to the moment of the spring and alternately less than the minimum and greater than the maximum moment caused by the spring.

8. A flasher of the hot-wire type as claimed in claim '1, in which the wire is continually iny :an electric circuit through the flasher and the current passing through the wire is varied by periodically establishing a circuit in shunt of the wire, whereby the wire is alternately heated and permitted to cool.

9. A flasher, comprising: a switch arm pivotallyxmounted between. its ends, one endfportion being substantially yrigid andthe other end ,portion `being resilient, `an electrical contact in the path of movement of the switch arm, a spring biasing the switch arm at .constantly increasing moment as it approaches the contact, anda tensioned wire fandmeans to intermittently heat the same, the wire having one end anchored and the f otherl end attachedto the resilient end portionof the switch arm for. supplying a moment acting counter rto the moment of the spring and alterf natelyless than the minimum and greater than ythe maximum moment caused bythe spring.

l0. Ina asher for interrupting an electrical circuit at frequent regular intervals, a stack of superimposed plateshaving substantially continuous similar peripheries forming a housing, one of the plates being resilient and having an integral portion within the periphery ofthe plates forming a switch arm substantially coplanar with the plate and pivotally attached to the peripherythereof for pivotal movement `in a plane. perpendicular tothe plate.

11. vIn a iiasher for interrupting an electrical circuit at frequent regular intervals, a stack of superimposed plates having substantially` continuous similar peripheries forming a housing, one of the pla-tes being resilient and having an integral portion within the periphery of the plate forming a switch arm substantially coplanar with the plate and pivotally attached to the periphery thereof for pivotal movement in a plane perpendicular to the plate, the pivoted mounting being formed by a pair of overlapping offset kerfs in S ythe plate at each side of the switch arm.

12. In a liasher for interrupting an electrical circuit at frequent regular intervals, a stack of superimposed pla-tes having substantially continuous similar peripheries forming a housing, a switch arm mounted for pivotal movement within the housing, and one of the plates being resilient and having an integral portion within the periphery of the plate forming a switch-arm-biasing spring pivotally mounted on the periphery for pivotal movement in a plane perpendicular to the plate, the pivotal mounting being formed by a pair of overlapping offset kerfs in the plate at each side of the spring.

13. In a flasher of the hot-wire type, a stack of superimposed plates having substantially continuous similar peripheries forming a housing, one of the plates forming a switch arm and a switch arm biasing spring both substantially coplanar with the plate and pivotally mounted on the periphery thereof for pivotal movement in =a plane perpendicular to the plate.

14. A unitary organization constituting a flasher for periodically interrupting a fiasher circuit combined with a relay responsive to current ilowing through the flasher circuit for controlling a monitor circuit showing operation of the flasher circuit, said flasher and relay comprising a stack of superimposed plates having substantially continuous similar peripheries formingY a housing, one of the plates including a pivotally-mounted switch arm biased to closed position to complete a low resistance asher circuit through the flasher, a hot-wire continuously in the flasher circuit for moving the switch arm to interrupt the low resistance flasher circuit, and another of the plates including a relay switch arm biased to closed position to energize the monitor circuit, and a second hot-wire in series with the flasher circuit and responsive to drop in current through the flasher circuit to a predetermined minimum to move the relay switch arm against its bias and thereby interrupt the monitor circuit.

15. A combined flasher and relay as claimed in claim 14, in which the plate including the flasher switch arm and the plate including the relay switch arm are similar.

16. A flasher comprising: a stationary contact and a movable contact; a pair of spaced pivots; shiftable means extending operatively from one pivot to the other, the movable contact being carried by said shiftable means and said shiftable means being movable towards and away from said stationary contact and continuously biased in one direction; resilient energy-storing means located outside of the space between parallel planes-passing through said pivots at right angles to a line connecting the pivots, said energy-storing means being operatively connected to said shiftable means; and hot-wire control means connected to the energy-storing means and operative to intermittently stress the energy-storing means to store energy therein, the stored energy opposing the bias of the shftable means, the

l2 stored energy periodically being of such magnitude as to overcome the bias of the shiftable means so as to actuate said shiftable means, thereby releasing a portion of the stored energy, the remaining stored energy being additionally released over an interval of time by action of the control means decreasing the stress imposed upon the energy-storing means.

ROBERT S. PERRY.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,256,499 Schmidinger Sept. 23, 1941 2,291,895 Harmon Aug. 4, 1942 2,354,635 Harmon July 25, 1944 2,367,614 Finlayson Jan. 9, 1945 2,368,679 Popp Feb. 6, 1945 2,388,712 Schmidinger Nov. 13, 1945 2,419,072 Hall Apr. 15, 1947 2,458,518 Kohl Jan. 11, 1949 2,525,044 Puerner Oct. 10, 1950

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