US2754392A - Circuit interrupter - Google Patents

Description

July 10, 1956 F. BENEDIK CIRCUIT INTERRUPTER 2 Sheets-Sheet 1 Filed Nov. 4, 1952 FIG. 4-.

FIG. 3).

INVENTOR.

y 0, 1956 F. BENEDIK 2,754,392

CIRCUIT INTERRUPTER Filed NOV 4. 1952 2 Sheets-Sheet 2 FIGS. FIG. 6.

INVENTOR.

United States Patent CIRCUIT INTERRUPTER Fedor Benedik, New York, N. Y.

Application November 4, 1952, Serial No. 318,582

7 Claims. (Cl. 200-422) The present invention relates to improvements in electrical circuit interrupters, and in particular to a circuit interrupter of the bimetallic type adapted to interrupt a pair of electrical circuits alternately and successively.

The invention finds particular application in the so called electric lamp flasher which contains a bimetallic element connected Within the circuit of the lamp and adapted to act as a switch for automatically lighting and extinguishing the lamp. it has hitherto been attempted to devise a simple circuit interrupter which could be incorporated in the circuits of a pair of lamps and operate to illuminate and extinguish both lamps alternately. Need for such an arrangement is manifest in advertising displays or the like, where alternately blinking lights tend to catch the eye of passersby. For such use, however, it is desirable that the two lamps be illuminated for substantially equal periods, and that the periods of illumination be substantially equal to the periods of extinguishment. It is also essential that one lamp light immediately upon the extinguishment of the other, so that there be no overlapping of extinguishing periods of illuminating periods.

The double-acting circuit interrupters hitherto devised have proved ineifective in meeting the aforementioned requirements since most were designed along the lines of the conventional single-bulb flasher with a contact mounted on either side of the reciprocating bimetal in such a manner that the bimetal would meet one contact on heating, and the other contact on cooling. Since the reciprocating travel of the conventional bimetal is, however, within an almost microscopic distance, it was a practical impossibility to adjust the minute distance between the contacts to insure proper electrical contact with both contacts, and at the same time to allow for operating differences caused by temperature variation, voltage fluctuation, etc. in other types of double-lamp flashers, two lamps of unequal wattage were connected in series across a line with the bimetal adapted to short out the high voltage lamp at periodic intervals. Such an arrangement, however, required that the wattage difference in the lamps be too large for practical commercial application.

I provide an improved circuit interrupter utilizing either a single bimetal or a pair of bimetals adapted to actuate a pair of switches, each of the switches being in series with a separate lamp circuit. The switches are arranged for positive interaction, so that when one switch is closed, the other switch is instantaneously opened.

An object of the invention is to provide a circuit interrupter of the type described in which two lamps are in circuits independent of each other, so that the lamps may be of equal wattage and the operation of one lamp continues even if the other lamp is damaged or removed.

Another object of the invention is the provision of a circuit interrupter of the type described which is operative to cause both circuits to be opened and closed for substantially equal periods.

Still another object of the invention is the provision of a circuit interrupter of the type described in which the Patented July 10, 1956 alternate circuit interruption is instantaneous, that is, one circuit is opened at the same instant that the other is closed.

Other objects and advantages of the invention will be apparent in the course of the following specification and drawings which show a practical application of the invention by way of example, rather than in a limiting sense.

Pig. 1 is a side elevational view of the circuit interrupter incorporating a pair of bimetallic elements, with the schematic circuit therefor including a pair of lamps, and the bimetallic elements in their unheated positions.

Fig. 2 is a side elevational view of the assembly of Pig. 1, but showing the bimetals in their heated and flexed positions.

Fig. 3 is a side elevation of a modified form of circuit interrupter having a single bimetallic element which is shown in its unheated position.

Fig. 4 is a side elevation of the circuit interrupter of Fig. 3, with the bimetal in its heated position.

Figs. 5 and 6 are side elevational views of another modification of a single bimetal circuit interrupter respectively showing the bimetal in its unheated and heated positions.

Figs. 1 and 2 illustrate a preferred embodiment of the invention which includes a pair of flat bimetallic strips 10 and 11 rigidly mounted, as by means of rivets 14, 15 to an insulated base 12.

The bimetals 19 and 11 are preferably of the same size and shape for convenience of manufacture, and are of the usual type which will bend or flex when heat is applied thereto. As a typical example, the bimetals may be made of a thin strip of brass fused flat against a thin strip of steel.

The bimetal it) carries a rigid insulated plate 16 and an electrically-conductive spring element 17. The plate 16 is rigidly mounted by a rivet 18 to the top of bimetal 10 as an upstanding extension thereof. The rivet 18 also secures to said bimetal 10 one end of said spring element 17, the rivet being made of a conductive material to electrically connect said spring element 17 to said bimetal 10.

The spring element 17 is made of a thin strip of flexible and resilient material such as Phosphor bronze and is bent to form a top bracket 19 of inverted U-shape and an integral elongated depending arm 17a. The latter is bent upon itself to form a depending fold or bight and its free end is secured to the bimetal 1t) and plate 16 by the rivet 18. T he folded arm 17a enhances the resiliency of the spring element 17 to permit a springy motion of the bracket 19 relative to the plate 16.

The bracket portion 19 of element 17 presents two spaced parallel arms which carry respective electrical contacts 20 and 21. These contacts face in the same direction, namely the direction in which the bimetal 10 will bend when heat is applied thereto, or to the right in Figs. 1 and 2. The insulated plate 16 has secured thereto a contact 22 which faces contact 20 and is normally urged into engagement therewith by the tension of the resilient element arm 17a. A contact 23 is fixed to the top end of bimetal 11, and is also electrically connected thereto. Said contact 23 faces the contact 21 and is normally spaced from contact 21 when the bimetals 10 and 11 is in its straight unflexed position of Fig. l. Contact 22 is insulated from the bimetal 10 by the plate 16, and carries a connecting lug 24 electrically-connected by a lead wire 25 to a terminal 26 which may be in the form of a rivet secured to the base 12. The rivets 14 and 15 previously mentioned, may also be designated as terminals.

The bimetals 10 and 11 are covered by layers of insulation 26 such as asbestos, mica, or the like. A heater coil 28, which may be made of Nichrome wire, is wound around the insulation of bimetal 10. A similar heater coil 29 is wound around the insulation of bimetal 11.

One free end of the heater coil 28 is electrically connected to the body of bimetal 10, the other end thereof being electrically connected to the terminal 14. Similarly the free ends of heater coil 29 are respectively electrically connected to the body of bimetal 11 and to the terminal 15. Thus in the electrical circuit of the unit, both heater coils 28 and 29 are in effect connected in parallel between the conductive bodies of both bimetals and 11.

As shown schematically in the drawings, the terminal 14 is adapted to be connected by a wire 31) to the terminai 31 of a power line which may carry the normal 110 volt A. C. or D. C. line current. The other power line terminal 32 may be connected to terminal 15 by a wire 33. Terminal 26 is also connected to power line 31 by a Wire 35. The wires 30 and 35 are in series with respective electric lamps 34 and 36.

Since the heater coils 23 and 29 are wired in parallel between the bimetals 10 and 11, these two coils will heat simultaneously when line current is supplied through terminals 31 and 32. To actuate heater coil 28, current supplied through wire 33 flows through terminal 15, bimetal 10, thence through heater coil 28 to terminal 14 and through wire 30 and lamp 34 to power line terminal 31. Current from wire 33 also passes through heater coil 29 and through bimetal 11, terminal 14 and wire 30 to power Iine'terminal 31. Although current flowing through Wire 30 passes htrough the filament of lamp 34, the lamp 34 does not light since the heater coils 28, 29 are in series therewith and dissipate the greater part of the current in heating. Current also flows through a parallel circuit through wire 33, bimetal 10, rivet 18, spring element 17, the closed contacts 20, 22, wire 25, terminal 26, wire 35 and lamp 36, lighting said lamp 36.

When the coils 28 and 29 are energized, the bimetals 10 and 11 are quickly heated so that they begin to bend toward each other. The bending of bimetal 10 toward the right from its position of Fig. 1 carries the attached plate 16 and spring element 17 toward bimetal 11, while at the same time, bimetal 11 is bending to the left and toward spring element 17. The contacts 21 and 23 are thus brought into firm pressing engagement which in turn pushes bracket 19 to the left relative to the plate 16 and against tension of the spring arm 17a. Movement of the bracket 19 relative to plate 16 immediately separates contacts 20 and 22 which remain spaced from each other as long as contacts 21 and 23 are in engagement.

Immediately upon separation of the contacts 20 and 22,

the circuit through lamp 36 is opened and said lamp 36 is extinguished. At the same time another circuit is closed by the engagement of contacts 21 and 23, this circuit leading through wire 33, terminal 15, bimetal 10, rivet 18, spring element 17, the closed contacts 21, 23, bimetal 11, terminal 14, wire 30, and lamp 3'4, lighting the latter. It will be noted that this circuit shorts out the heater coils 28 and 29, so that the current bypasses said coils and the bimetals 1t) and 11 are allowed to cool while contacts 21 and 23 are closed.

As the bimetals 119 and 11 cool, they straighten from their bent positions of Fig. 2 until the contacts 21 and 23 separate, at Which time the spring arm 17a returns the bracket to its original position of Fig. 1 relative to the plate 16 and the contacts 20 and 22 are again brought into engagement. These heating and cooling cycles are repeated automatically -so that the lamps 34 and 36 are successively and alternately lighted and extinguished.

The-lamp 36 is thus lighted during the heating period of the bimetals 10 and 11, while the lamp 34 is lighted during the cooling period of said bimetals. To maintain a substantially uniform illuminating period for both lamps, the bimetals 1t} and 11 are made in such a manner that their cooling period is substantially equal to their heating period. This may be accomplished bysuch Wellknown expedients as selecting suitable bimetal dimensions and component bimetal materials, varying the length, resistance, or pitch of the heater coils, etc.

The embodiment shown in Figs. 1 and 2 in which a pair of oppositely-bending bimetals are utilized presents distinct advantages. The opposed movement of both bimetals 1t) and 11 insures sharp and positive meeting and breaking of the contacts. In addition this embodiment is of particular application when a rapid alternate flashing of the lamps is desired since the combined movement of both bimetals toward each other reduces by approximately half the time required for the same operation by a single bimetal. However, if desired for the sake of economy of manufacture, or if extremely rapid flashing is not desired, either of the two bimetals 10 or 11 may be eliminated without impairing the operative efiectiveness of the unit. Figs. 3 and 4 show a similar unit in which the bimetal 11 is eliminated while Figs. 5 and 6 show a unit in which bimetal 10 is eliminated. Both of these units have an identical mode of operation.

In the flasher unit shown in Figs. 3 and 4, the base 41 has an elongated upstanding extension arm 41a which replaces the bimetal 11. A bimetal 4Q which is identical with the bimetal 11) of Figsl and 2 is mounted on base 49 by means of a rivet terminal 4-2. Bimetal 40 carries an insulated plate 44 an the bent leg of a spring element 45 which are secured thereto by a rivet 43. The spring element top bracket 46 has a pair of contacts 47 and 43 which are mounted to face in the same direction. A contact 49 mounted on plate 44 faces contact 47 and is normally maintained in engagement therewith by the tension of the resilient bent leg of element 45. Contact 49 carries a connection lug 56 which is connected by wire 51 to a terminal rivet 52.

The upstanding base arm 41a has fixed contact 53 which faces contact 48 and is connected by a lug 54 and wire 55 to a terminal rivet 56.

The bimetal 413 is covered by a layer of insulating material 57, around which is wrapped a heater coil 53. One end of the latter is connected to the body of bimetal 40, while the other end is connected to terminal 56.

The terminal 42 is connected directly to a power source terminal 5? through a wire 60. The other power source terminal 61 is connected to terminal 56 through a lead 62 in which a lamp 63 is connected. Terminal 52 is also connected to the power source terminal 61 by a wire 64 which also leads through a lamp 65.

When the bimetal is in its normally straight position of Fig. 3, the contacts 47 and 43 are in engagement, and current flows from the power terminals 59, 61 through a circuit formed by wire 6%, terminal 42, bimetal 40, heater coil 53, terminal 56, wire 62, and lamp 63; heating the coil 58, but leaving the lamp 63 unlighted. At the same time current flows through a parallel circuit formed by wire 6%, terminal 42, bimetal 40, rivet 43, spring element 45, contacts 47 and 49, lug 50, wire 51, terminal 52, and lamp 65; lighting said lamp 65.

As the bimetal 41 is heated by coil 53, it bends toward the base leg 41a until contacts 48 and 53 meet. The bending force of bimetal 4t) presses contacts 48 and 53 together, thereby moving the top bracket 46 relative to the bimetal 4i) and separating contacts 47 and 49, as shown in Fig. 4. The circuit through lamp 65 is thus opened. At the same time, the engagement of contacts 48 and 53 closes a circuit through lamp 63, the current flowing through wire 66, bimetal 4t) and its connected spring element 45, across the closed contacts 48, 53, and through wires 55 and 62 through the lamp 63 to light the latter. This circuit shorts out the heater coil58, so that the heater coil 58 and bimetal 40 are cooled while the contacts 48, 53 are in engagement.

After the bimetal 45 has cooled sufliciently, it straightens and allows the contacts 48 and 53 to separate, thereby causing the resilience of spring element 45 to urge the contact 47 into engagement with the contact 49, and the flashing cycle is repeated.

In the flasher shown in Figs. 5 and 5, the bimetal 10 of Figs. 1 and 2 is eliminated. This flasher has a base 70 which has an upstanding leg 70a. To the lower end of the latter is secured a spring element 71 by means of a rivet 72 which also serves as a terminal. The spring element 71 has an elongated resilient arm 73 which is integral with a top U-shaped bracket 74, the latter having secured thereto a pair of contacts 75 and 76. Contact 75 faces a contact 77 mounted on the base leg 70a and is normally urged into engagement with said contact 77 by the resilient element arm 73. Contact 76 faces a contact 78 which is secured to a bimetal 79 mounted 011 a base 7 by a rivet 80 which also functions as a terminal.

The bimetal 79 has an insulated covering 81 around which is wound a heater coil 82 whose ends are respectively connected to the body of bimetal 79, and to terminal 72.

Contact 77 carries a lug 83 which is connected by a wire 84 through a lamp 86 to a power terminal 85. Terminal 72 is connected by a wire 87 to the other power terminal 88. Terminal 80 is connected by a wire 90 to the power terminal 85, the wire 80 having a lamp 91 connected intermediate its ends.

The circuits shown in Figs. and 6 are identical in operation to that of the flasher illustrated in Figs. 3 and 4, and will not be described in detail. When the device is in the normal position shown in Fig. 5, the lamp 86 is lighted and the coil 82 is heated causing the bimetal '79 to flex in the direction of the spring element 71. When the contacts 76 and 78 engage, the pressure of the bimetal 79 upon the resilient spring element 71 causes the bracket 74 to move to the left to its position shown in Fig. 6 in which the contacts 75 and 77 are separated. In this position, the lamp 91 is lighted while the circuits through lamp 86 is broken and the heater coil 82 is short circuited.

In Figs. 1 and 2, the contacts 20 and 22 may be designed as a first switch and the contacts 21 and 23 may be designated as a second switch, the first switch regulating the circuit through lamp 36 and the second switch regulating the circuit of the lamp 34. The switches are actuated by the coaction of the bimetals and 11 with the spring element 17 in the manner of a single-pole, double-throw switch. Similarly, in the embodiments of Figs. 3 and 5, the respective pairs of contacts 47, 49 and 75, 77 may be designated as first switches, while the respective pairs of contacts 48, 53 and 76, 78 may be designated as second switches.

While preferred embodiments of the invention have been shown and described herein, it is obvious that numerous alternations, omissions and additions may be made Without departing from the spirit and scope of the invention. In particular, it is to be understood that the use of the invention is not to be limited to the illumination of elecric lamps, but that other types of electrical circuits may be effectively regulated thereby.

What is claimed is:

l. A lighter flasher for successively and alternately lighting and extinguishing a pair of electric lamps, said flasher comprising a base, an insulated member mounted on said base, a U-shaped bracket member having a pair of spaced parallel arms and a resilient extention leg, connected to said insulated member, a bimetallic member mounted on said base and being adapted to flex in the direction of said bracket member in the presence of applied heat, a first and second electrical contact respectively mounted on the parallel arms of said bracket member and facing in the some direction, a third electrical contact mounted on said insulated member and facing said first contact, a fourth electrical contact mounted on said bimetallic member and facing said second conta said resilient extension leg normally urging the bracket member to a position in which said first and third contacts are in engagement and said second and fourth contacts are spaced from each other, said bimetal being bendable when heated to press the fourth contact against said second contact and move said bracket meniber to a position in which said first and third contacts are brought out of engagement, an electrical heater element mounted proximate to said bimetal for supplying heat thereto and connected across said second and fourth contacts, means for connecting a first electrical lamp circuit in series with said first and third contacts, means for connecting second electrical lamp circuit in series with said second and fourth contacts, and a third electrical circuit through said heater element, said third circuit being in parallel to said first circuit, said second circuit shorting out said third circuit.

2. A light flasher according to claim 1 in which a second bimetallic member is also mounted on said base, said bimetal carrying said insulated member and being adapted to bend in the direction of said first bimetallic member in the presence of applied heat and carry said bracket toward said fourth contact.

3. A light flasher according to claim 2 in which a second heater element is associated with said second bimetallic member, said second heater element being wired in parallel to said heater element.

4. In an automatic circuit interrupter, a spring member, an insulated support mounting said spring member and having a contact insulated from said spring member, said spring member having an elongated spring arm connected at its end to said support, said spring arm extending above said support and terminating in a lateral leg extending across the top of said support, said lateral leg terminating in a depending leg parallel to the spring arm, the depending leg and the spring arm bracketing the support member, said depending leg having a contact which faces and is alined with the contact of the support, the spring arm also having a contact facing in the same direction as said depending leg contact, the resilience of said spring arm urging the depending leg contact into pressing engagement with said support contact, a fourth contact facing said spring arm contact and normally spaced therefrom, and a heat responsive member movable to bring said fourth contact and said spring arm contact into pressing engagement, thereby causing said spring arm to flex and separate said depending leg contact from the contact of said insulated support.

5. A device according to claim 4 in which a heater coil is mounted in proximity to said heat-responsive member, said heater coil being connected across the fourth contact and the spring arm contact.

6. In an automatic electric light flasher for successively and alternately flashing a pair of lamps, a support base, first and second bimetal elements mounted on said base parallel to and spaced from each other and adapted to flex toward each other in the presence of applied heat, said bimetals each having an electrical contact, the contacts facing in the same direction, a conductive spring arm mounted on the first bimetal and movable therewith, said spring arm havin a head of inverted U-shape having a pair of parallel arms bracketing the first bimetal, the arms having respectively a third and fourth electrical contact facing in the same direction and positioned to contact respectively the first and second bimetal contacts, said spring arm being resilient and normally urging said first and third contacts into pressing engagement, the second bimetal being positioned in unflexed position with its contact spaced from the fourth spring arm contact, and heater elements for said bimetals connected across said second and fourth contacts to be shorted out when said second and fourth contacts are closed and to be energized when said second and fourth contacts are open, said heater elements when energized being adapted to heat said bimetals sufiiciently to cause movement thereof to positions in which the second and fourth contacts are closed and the first and third contacts are opened.

7. In an automatic electric light flasher for successively and alternately flashing a pair of lamps, a support base, first and second bimetal elements mounted on said base parallel to and spaced from each other and adapted to flex toward each other in the presence of applied heat, said bimetals each having an electrical contact, the contacts facing in the same direction, a conductive spring arm mounted on the first bimetal and movable therewith, said spring arm having a head of inverted U-shaped having a pair of parallel arms bracketing the first bimetal, the arms having respectively a third and fourth electrical contact facing in the same direction and positioned to contact respectively the first and second bimetal contacts, said spring arm being resilient and normally urging said first and third contacts into pressing engagement, the second bimetal being positioned in 'unfiexed position with its contact spaced from the fourth spring arm contact, and heater elements for said bimetals connected across said second and fourth contacts to be shorted out when said second and fourth contacts are closed and to be energized when said second and fourth contacts are open, said heater elements when energized being adapted to heat said bimetals suificiently to cause movement thereof to positions in which the second and fourth contacts are closed and the first and third contacts are opened, and means for attaching a lamp in series with said first and third contacts and a lamp in series with said second and fourth contacts.

References Cited in the file of this patent UNITED STATES PATENTS 1,262,645 Conner et al. Apr. 16, 1918 1,684,709 Lowenstein Sept. 18, 1928 1,743,053 Traver Jan. 7, 1930 1,916,671 Hanser et al. July 4, 1933 2,076,275 Jorgenson Apr. 6, 1937 2,236,699 Riche Apr. 1, 1941 2,329,119 Jacobs Sept. 7, 1943 2,384,372 Eaton Sept. 4, 1945 2,535,969 Tramontini Dec. 26, 1950 2,599,473 Miller June 3, 1952 2,689,288 Wells Sept. 14, 1954 FOREIGN PATENTS 44,741 Austria May 31, 1925 18,382 Australia July 11, 1934

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