US2388033A - Flasher switch - Google Patents

Description

Patented Oct. 30, 1945 UNITED STATES PATENT OFFICE Application December 19, 1941, Serial No. 423,887

9 Claims. (Cl. MIL-113) This invention relates to flasher switches such as used on automobiles for indicating to the driver in the rear that the brakes have been applied in order that the vehicle may be stopped. In some installations the flasher is used to cause the flashing of a lamp on the left side of the rear of the vehicle to indicate a left turn, and to cause the flashing of a lamp on the right side 01' -..the vehicle to-indlcate a right turn.

It is an object of the present invention to provide a flasher of durable construction which is reliable in operation and which can be produced at relatively low cost. In accomplishing this ob- Ject- I provide a novel movable switch actuating element in the form of a strip or flipper bar of flexible metal such as phosphor bronze. The bar is initially so shaped as to provide a curved or arched central portion having a radius of curvature of substantial dimensions and end portions which extend away from the center of curvature of the central portion. The bar is assembled in the switch device with its ends located between supports which pivotally engage the ends, and with its center located between stationary parts which provide for a limited lateral movement of the bar. The bar is normally so stressed by the supports at its ends that the bar tends to move laterally in the direction toward which its concave side faces. In this position of the bar, the switch contacts are separated. Due to the heating effects of an electric current passing through a thermal element, said element operates to increase the distance between the bar end supports thereby causing such change in the stresses of the bar as to cause it to move laterally in the direction toward which its convex side faces. This later movement causes the switch contacts to engage and to short-circuit the thermal switch which, on cooling, shortens the distance between the bar end supports and causes the bar to return to its normal position in the switch device.

of Fig. 2 and shows a top side view of a flasher embodying the present invention, the cover of the In this way, the current flowing to a signal lamp either through the thermal element or through a short-circuit around it is caused to vary alternately between a relatively high value suillcient to cause a lamp to burn brightly and a lower value which is insufllcient to cause the lamp to burn noticeably. I

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment of the invention is clearly shown.

In the drawings:

8- 1 is a view in the direction of arrow is flasher being shown in section and the base portion being shown in section on the line lb--lb of Fig. 2.

. Fig. 2 is a plan view of the flasher with the cover removed, and is also a wiring diagram of the flasher circuit.

Fig; 3 is a bottomside view taken in the direction of the arrow 8 01' Fig. 2.

Fig. 4 is a plan view of the flipper bar in its initial condition before assembling with the flasher.

Fig. 5 is an edge view of the bar as shown in Fig. 4.

Fig; 6 is an edge view of the bar when associated with other elements of the flasher and when in elongated or contact making position. (Fig. 2 shows the bar in shortened condition in which the flasher contacts are separated.)

Figs. 7 and 8 are charts explaining the operation of the bar.

The flasher comprises a metal base 20 having an extension 2i providing a bracket by which the flasher may be mounted upon a part of the automobile. The base 20 insulatingly supports a pivot stud 22, the shank 23 of which passes through a metal washer 24 and insulating plate 25, a large hole 26 in base 20 and an insulating plate 21 and through a washer 28. The upper end of the rivet as seen in Fig. i is upset as shown at 29. The stud 22 provides a bearing for a hub or bushing 30 carrying a lever 31 having a pair of arcuate notches at 32 and a single V-notch at 33.

Base 20 insulatingly supports a bracket 35 secured by rivets 36 and 31 after the manner of securing the stud 22 to the base 20. As shown in Fig. 3, bracket 35 is provided with an upright portion 38 and with a horizontal portion 39 having a single V-notch 40. Between the lever 3i and the part 39 of bracket there is located a flipper bar 4|. As shown in Figs. 4 and 5 the bar 4! is initially shaped so that its central and major portion from bcd is arched or curved. From the portion bc--d, there extend end portions ab and d-e which lie substantially in the same plane. These end portion are provided with notches 42 and 43. The bottom of the notch 42 is received by the bottom of the notch iii of the bracket 35. The bottom of the notch 43 is received by the bottom of the notch 33 of the lever 3!. The center 0 of the arched portion b-cd carries at its center a movable contact 44. The portion 0-?) is provided with an extension or tall 45 to which one end of a flexible wire it is soldered as shown in Fig. 2. the other end of wire 46 being soldered to the upright part 38 of bracket 35.

A bracket 50 having an upright portion BI is insulatingly supported by the base 20 and is attached thereto by rivets 52 and 53. An iron wire .54 is connected with the part BI and with the lever 3|. In making this connection, one end of the wire 54 is passed around the notches 32 of lever 3| as shown in Fig. 2, the bar 4! is placed between the parts 39 and 3| and the wire 54 is maintained under such tension before attaching to part 5| that the bar 4| will be bent normally as shown in Fig. 2. It will be seen that the end of portions -D and d-e of the bar 4! have been bent away from the plane which they originally occupied as shown in Fig. 5. The bending of portions w-b and d -e in this fashion so stresses the arched portion bcd as to urge the rivetted part 44a of the contact 44 against a stop 55 provided by bracket 56 insulatingly supported by the plate 20 and secured by a rivet 51. When the wire 54 elongates due to increase in temperature to a certain value by the passage of an electric current through the wire, the lever 3| is permitted to move counterclockwise under the action of the stressed bar 4!, thereby increasing the distance between the notches 3d and 33. This allows the parts cb and de to bend toward the horizontal as viewed in Fig. 2, thereby permitting the portion b-cd to approach the shape it had originally as shown in Fig. 5. Therefore the contact dd moves upwardly from the position shown in Fig. 2 to that shown in Fig. 6 until the contact 46 engages a contact 38 supported by a bracket 6! insulatingly carried by the plate 28 and secured by rivets t2, t3 and 66. The engagement of contacts 44 and 56 completes a short-circuit around the wire 54 thereby reducing the flow of current to the wire so that its temperature and its length decreases. As the length of the wire 5L3 decreases, the pressure applied by the parts 39 and Si to the bar ill increases, thereby causing the bar to take the position as shown in Fig. 2. The separation of contact 44 from contact 5d causes the short-circuit of the wire 54 to be interrupted so that full current flows again through the wire 56 to produce its elongation. Thus the cycle of closing and opening the contacts 64, til is repeated so long as a stop-light switch or a direction-signal switch is closed.

The switch it, which may be a stop-light switch or a direction signal switch, connects a battery ll grounded at 72 with a terminal 83 insulatingly supported by the plate 28 and connected by fuse M with a clip 75 connected by rivet 63 with the bracket 5i. Bracket 5!! is provided with an upright lug it to which a rivet ll secures a magnetizable metal resilient blade or armature i8 carrying a contact it normally separated from but movable into engagement with the pole face 80 of a magnetizable core at surrounded by magnet coil 82 which is connected at 83 with bracket 35 and at M with a strip 35 providing a terminal to which the flasher lam 86 grounded at M ls connected. Magnet core 38 is supported by an upright lug 39 of a bracket 9c insulatingly supported by plate 20 and attached by rivets 9i and 92. Bracket 96 is connected with a pilot or indicator lamp 93 grounded at 34. The lug it of bracket 5! is connected by wire 95 with bracket 56.

Th flasher unit begins to function when switch 10 is closed. Current then flows from the battery through the following circuit: switch 10, terminal 13, fuse l4, clip 15, bracket 6!, wire 95, bracket 50,

wire 54, lever 3!, bar 4|, bracket 35, magnet coil 82, strap 35, lamp 88 and ground connections 81 and 12. The iron wire 54 being included in this circuit, the resistance-is such that lamp 86 does not burn noticeably and the magnet coil 82 is inefiective to cause the downward movement of the armature l8 and the lamp 93 does not burn. The flow of current through the wire 54 causes it to lengthen, thereby causing the bar 4| to bend from the position shown in Fig. 2 to that shown in Fig. 6, thereby introducing a short circuit around the wire 54 and increasing the current flowing through the lamp 83 so that it burns brightly and increasing the current flowing through the magnet coil 82 to such value that the armature 18 is attracted downwardly. Downward movement of armature 18 causes contact 19 to engage contact thereby connecting indicator lamp 93 with the battery which burns to indicate that the flasher lamp 36 is burning. If lamp 86 should burn out, lamp 93 will not burn since no current would be flowing through the magnet coil 82 and the armature 78 would move upwardly to cause contact 19 to be separated from pole face 80. While the lamps and 93 are burning, the wire 54 is short-circuited so that its temperature will.

decrease to cause it to shorten and to cause the bar ii to return to the position shown in Fig. 2, thereby interrupting the short circuit around the wire 54 so that the flow of current through the wire Ed is ire-established and the wire 54 again elongates. Thus the intermittent burning of the lamps 86 and 33 occurs so long as the switch 10 remains closed.

The normal air gap between contact 13 and pole face 38 is adjusted by bending a lug 99 integral with bracket 5i and against which the armature blade 78 is normally biased.

The apparatus is housed by a drawn metal cover 6% having flanges HM and W2 so shaped as to receive the base 20. The cover is secured to the base by bending tangs of the cover into notches m3 of the base.

It is believed that the bar 48 operates in the manner described on account of certain changes in stress therein. These changes will now be described with reference to Figs. 7 and 8.

In the charts, Figs. 7 and 8, dot-dash line 50- represents the neutral axis of the bar ll. Above axis cy, the material of the bar is under compression; and below the axis :c-y, it is under tension. In the chart, Fig. 7, the bar 4a is in the normal position shown in Fig. 2. The bending ce is to over-balance stress bd; thereforebar M moves downwardly in Fig. '7, or laterally in the direction toward which the concave side of the arch faces.

When, due to heating the wire 56, the distance it between bar end supports 40 and 33 increases from the value shown in Fig. 7 to that shown in Fig. 8, the stresses ac and 0-6 diminish (as indicated by light lines in Fig. 8) so that the stress .b-d tending to increase arch camber overbalances stresses a-c and ce (as designated by heavy line 12-41 in Fig. 8), and the bar moves upwardly to the position shown in Figs. 8 and 6, or in the direction toward which the convex side of the bar faces.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other form might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A flasher switch comprising a detachable flipper-bar having initially an arched central portion and end portions extending from the central portion, supports pivotally engaging the end edges of the bar and spaced apart a distance less than the initial distance between said end edges, one of said supports being relatively movable in the direction lengthwise of the bar, spaced fixed stops located between the supports and between which the center of the bar is located in orderto limit lateral movement of the bar arch in either direction, the location of the stops relative to the supports being such that, when the bar is assembled between the supports and stops, the end portions of the bar are bent relative to the arch in the direction toward which the convex side of the arch faces and the camber of the arch becomes smaller than initially, a thermostat having one end fixed and the other end attached to the movable support limiting the normal spacing of the supports to a dimension such that the stresses produced by bending the end portions of the bar exceed the stress in the arch tending to increase its camber, thereby causing the bar arch to move laterally in the direction toward which its concave side faces, an electric circuit normally including the thermostat and the bar for connecting a current source with a lamp, the heating of the thermostat causing the bar to increase the distance between the supports to such dimension as. to cause the stresses produced by bending the end portions of the bar to become less than the stress in the arch tending to increase its camber whereupon the bar arch moves laterally in the direction toward which its convex side faces, and a circuit completed through a portion of the bar upon said later movement of the bar for short circuiting the thermostat.

2. A flasher switch according to claim 1 in which the electric circuit for connecting a current source with a lamp includes normally the thermostat and the bar in series, and in which the circuit which short-circuits the thermostat includes a contact located on the convex side of the bar arch and a contact which provides the adjacent fixed stop.

3. A flasher switch, comprising in combination; a base; a conducting stationary support attached to the base; a conducting movable support pivoted in the base; a stationary contact; a detach able flipper member, said member having end edge portions pivotally engaging the supports, said member being formed so that dimension between the edge portions thereof is greater than the distance between points where the edge portions engage the supports so that the member will be bowed so as to urge constantly the movable support in one direction; and a thermal wire having one end attached to a fixed point on the base and having the other end attached to the movable support and a ting to move the movable support in the opposite direction to maintain the flipper member out of engagement with a stationary contact, said wire being connected in a circuit including the movable support and the flipper and expanding when the flipper member is out of engagement with the stationary contact to permit the flipper member to urge the movable support in said one direction to allow the flipper member to engage the stationary contact to shunt the movable support and the wire whereby the wire contracts to actuate the movable support in the opposite direction against the urging force of the flipper member to separate same from the stationary contact. a

4. A flasher switch comprising in combination a base; a plurality of conducting stationary supports and a conducting movable support mounted on the base; a detachable flipper bar having initially a central arched portion and end portions extending from the central arched portion, one of said end portions pivotally engaging one of the stationary supports and the other end pivotally engaging the movable support; a wire adapted to be electrically heated having one end fixed to the other stationary support and having the other end attached to the movable support, said wire operable that, when the bar is assembled between its supports, the end portions of the bar are bent relative to the central arch thereof so that the arch becomes smaller than initially and thereby causes the bar to urge constantly the movable support in one direction; a stationary contact; a movable contact carried by the bar; and an electric circuit normally including the wire the movable support and the bar for connecting a current source with a lamp, the heating of the wire causing the wire to expand permitting the bar to urge the movable support in one direction and increase the distance between its supports whereby the arched portion of the bar moves laterally to move the movable contact into engagement with the stationary contact for short circuiting the wire and the movable support and allowing the wire to contract and move the movable support in the opposite direction to separate the contacts.

5. A flasher switch comprising in combination; a plurality of stationary support and a movable support; a detatchable flipper member having initially an arched central portion and having its respective ends pivotally mounied between one of the stationary supports and the movable support; a thermal wire fixed to the other stationary support and connected with the movable support, said wire normally urging the movable support in one direction to hold the flipper member under stress between its supports; a stationary contact; a movable contact carried by the flipper member; and an electric circuit normally including the wire and all of the supports for con necting a current source with a, lamp, the heating of the wire permitting it to expand to allow the flipper member to urge the movable support in one direction whereby the flipper member will move the movable contact with a snap action into engagement with the stationary contact to short circuit the wire the specified one stationary support and the movable support whereby the wire will contract and move the movable support in the opposite direction against the action of the flipper member to again place the flipper member under stress and separate the contacts with a snap action.

6. A flasher switch comprising a conducting stationary support and a conducting oscillatable support; a detachable flipper member flexed so as to provide a curved portion intermediate its ends, the edges of said ends pivotally engaging the supports; a movable contact carried by the curved portion of the flipper member; stops disposed on opposite sides of the flipper member for limiting the lateral movement of the flipper member in either direction, said flipper member constantly urging the oscillatable member in one direction to permit the flipper member to shift the movable contact into engagement with one of said stops for making a shunt circuit; a thermal wire having one end flxed and the other end connected to the oscillatable support to move the latter in the opposite direction to flex the flipper member in a manner that the movable contact is held against the other stop to open the shunt and circuit; circuit connections for the thermal wire for constantly connecting the thermal wire with a current source, said thermal wire expanding when the shunt circuit is opened to permit the flipper member to urge the oscillatable member in said one direction and to allow the flipper member to move the movable contact against the stop to establish the shunt circuit about the oscillatable support and the thermal wire, said movable contact when in engagement with said stop permitting the cooling of the wire whereby the wire actuates the oscillatable support in the opposite direction to flex the flipper member and open the shunt circuit.

7. A switch for flashing signal circuits comprising, spaced terminals; a stationary contact electrically connected with one of the terminals; a stationary support electrically connected with the other terminal; an oscillatable support; a detachable flexible contact supported by the supports; and a thermal expansible member fixed at one end and electrically connected with the stationary contact and having the other end electrically attached to the oscillatable support and operating to complete a circuit connection to the oscillatable support and also urge the oscillatable support in one direction of oscillation so as to place the flexible contact under stress and out of engagement with the stationary contact, the passage of current through the element causing the heating and expansion of the element to permit the flexible contact to move the oscillatable member in the opposite direction of oscillation until the flexible contact engages the stationary contact to shunt the element whereby said element cools and contracts to move the oscillatable member in the specified one direction causing the flexible contact to disengage the stationary contact.

8. An intermittently operating switch for electric circuits comprising a stationary contact; a

stationary support and an oscillatabie support; a flexible conducting member carrying a contact pivotally supported by the supports, said flexible member completing a connection for a pair of circuit paths, one circuit path being completed through a portion of the flexible member when the contacts arein engagement; and a thermal element capable of being elongated when heated having one end fixed and electrically connected with the stationary contact and having the other end electrically connected with the oscillatable support to complete the other circuit path, said thermal element when cool urging the oscillatable member in one direction against the bias of the flexible member to separate the contacts to permit current to pass through the thermal element and heat same, the heating of the thermal element permitting the flexible member to ur e the oscillatable support in the specified one direction causing the contact carried by the flexible member to engage the stationary contact to shunt the thermal element.

9. A switch for flashing signal circuits comprising, a base; spaced terminals; a stationary contact connected with one of the terminals; a stationary support electrically connected with the other terminal; an oscillatable support, said supports having side edges adjacent each other shaped to define oppositely presented notches to form pivots; a flexible conducting flipper carrying a contact and extending transversely of said supports and having its end edges pivotally retained in said notches for effecting the completion of. a connection in at least two circuit paths, said flipper operating to move the oscillatable support in one direction of oscillation causing the flipper to move its contact into engagement with the stationary contact to complete one circuit path through a portion only of the flipper; and a thermal responsive element having one end fixed and electrically connected with the specified one terminal and having the other end attached to the oscillatable support to complete another circuit path through the flipper, said thermo responsive element expanding when the contacts are separated permitting the flipper to move the oscillatable support in the specified one direction of oscillation and functioning to move its contact into engagement with the stationary contact to shunt the thermal element to permit the cooling of the latter whereby the oscillatable support will be moved in the opposite direction to separate the contacts.

KENNETH L. BERNINGER.

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