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Publication numberUS2635156 A
Publication typeGrant
Publication dateApr 14, 1953
Filing dateApr 3, 1951
Priority dateJan 19, 1951
Publication numberUS 2635156 A, US 2635156A, US-A-2635156, US2635156 A, US2635156A
InventorsOtto Welter
Original AssigneeOtto Welter
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Thermal circuit breaker
US 2635156 A
Abstract  available in
Images(1)
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Claims  available in
Description  (OCR text may contain errors)

April 14, 1958 o. WELTER 2,635,156

THERMAL. CIRCUIT BREAKER Filed April 3, 1951 Patented Apr. 14, 1953 UNITED STATES PATENT OFFICE Application April 3, 1951, Seriall No. 218,940 In Switzerland January 19, 1951` 8 Claims.

An embodiment of the thermal circult breaker according to my invention is shown by way of example in the accompanying drawing, wherein Fig. 1 is a sectional side elevation; and

Fig. 2 is an end elevaton, the protection cover being removed.

In these figures, Il indicates a supporting member or socket to which a housing 12 of insulating material is attached. A conducting lamella 13 with a contact Ill is conductively connected to a terminal sealed into the socket H. The slightly curved leaf spring member I together with a heat responsive elongated member or filament ll attached to its central portion forms an M-shaped element. A ball [8 attached to the lower end of a heat responsive elongated member or 'filament l'l is held in a recess 19 provided in a terminal 20. The lower end of the filament ll is passed through a slot 24 in the uppermost part of the terminal 2B and through a small opening 22 of the socket Il. The upper part of the terminal as well as the hole 23 of the socket I] are of, square section in order to prevent rotation of the terminal 28. The latter has a screw threaded mid portion cooperating with a nut 24 for adjusting the bias tension of the filament ll. The legs IGa of the U-shaped leaf spring IG are clamped into the socket ll and initially stressed in. such a way that the contact piece 25 fixed to the cross bar of the leaf. spring IB and conductively ,connected with the filament I l is normally kept remote from the fixed contact [4, the distance between the contacts. M and 25 being increased With increasing tension of the filament Il. In horizontally arrang'ed holes of the housing 12 one'V of which has square section, a frame 28 of insulating material is mounted slidably but unrotatably by means of its bolts 28 and 21 lthe latter of which serves as an Operating knob and is held in its rest position by a coil spring 29 (Fig, 1)

The operation of this device is as follows:

By pressing on the bolt 2'! the M-shaped elements 16 and Il are moved toward the conducting lamella |3 until contacts I4 and 25 are in electrical contact. In this position an electric current Will flow through terminal |5, conducting lamella |3, contact pieces M and 25, filament Il and terminal 20, thus increasing the temperature of the filament l '1. The leaf spring IB is held in its working position by the tension of the filament |1. With increasing temperature the filament ll is extended so that at a certain point the bending tension of the leaf spring |6 becomes sufiiciently large to overcome the resistance of the fil- 2 ament I'l. This position of the element IG, l'l is an unstable one. If the heating is continuedthe element l, i'l snaps back into its end position at the right whereby the contact pieces M and 25 are separated.

The engagement of the contact pieces 14 and 25 also takes place by a sudden snapping; in this case the increasing resistance of the filament l'l against its extension and the increasing resistance of the leaf spring IG against bending are overcome by the pressure on the bolt 21 up to the point where the unstable position is reached. After that the elastic tension of the filament ll is sufiicient for a further bendingof the leaf spring and producing a contact pressure thereby bending the lamella I 3.

By means of 'the nut 24 the bias tension of the filament is adjustable, Whereby the Circuit breaker Lnay be designed for different intensities at which the controlling current by heating the filament causes the opening of the switch.

The heating of the filament I? is obtained by covering one or several current carrying portions of the heat responsive member i? with an elastic, electrically insulating layer Ha on which a very thin conducting layer HZ) is applied. The insulating layer consists of a suitable artificial materia'l such as artificial resin, e. g. acetyl' cellulose which is brought to the member Il by dipping', spraying or laminating, or any suitable means.

The` conducting layer llb consists of platinum,

gold or'carbon and the like and may be applied by cathodic evaporation or thermal evaporating to one or both surfaces of the respective portion of the filament H. This thin conducting layer Ilb is electrically heated by a battery I'Id connected to the layer i lb by a conductor lc containing Va.

switch Ile during the operation of the breaker whereby the respective portion of the member I'l is heated through the electrically insulating layer Ha.

I wish it to be understood that I do not desire to be limited to the exact details of construction, design and operation shown and described, as modications falling within the scope of the appended claims, will be apparent to any person skilled in the art.

I claim:

1. A thermal circuit breaker, comprising, in combination, a resi1ient member including a cross-bar and three legs forming an M-shaped part, a supporting member in which the ends of the legs opposite the cross-bar are fixed, the central leg having a length diifering from that of the two outer legs and the longer leg or legs being slightly arcuated. and a control member fixed to aeaalsc said cross-bar, the resilient member having a portion exposed to the controlling temperature and being under control of a high ohmic heating element.

2. A thermal circuit breaker according to claim 1, the said high ohmic heating element consisting of a thin electrically conducting layer adapted to conduct a control current, the said conducting layer being applied to an insulating coating covering the same portion exposed to the controlling temperature.

3. In a thermal circuit breaker 'a supporting member and an M-shaped resilient switching member having a central leg, two outer legs and a cross-bar, the said central leg being adjustably fixed to said supporting member and the said two outer legs being clamped fast in said supporting member, the said central leg being shorter than the two outer legs and being coated with an electrically insulating layer which in turn is covered with a thin electrically conducting layer adapted to conduet a control current, and the said cross'- bar carrying a contacting element and a control member.

4. In a thermal circuit breaker a supporting member of insulating material, and an M-shaped resilient switching member` having a central leg, two outer legs and a cross-bar, the said cross-bar carrying a contact piece and being freely movable opposite a second contact piece carried by a contact spring clamped fast in the said supporting member, the said outer legs of the resilient switching member being clamped fast in said supporting member opposite the said contact spring, the said central leg being adjustably fixed to said supporting member between the clamping points of the said outer legs, the said central leg being shorter than the two outer legs and being coated with an electrically insulating layer which in turn is covered by a thin electrically conducting layer adapted to conduct a control current heating the said central leg in order to produce a switching over thethermal circuit breaker.

5. In a thermal circuit breaker, a thermally operable movable switch unit, comprising, in combination, a supporting member, a slightly curved leaf spring member mounted at one end on said supporting member; a contact member mounted on the other end of said leaf spring member; a heat responsive elongated member secured at one end to said other end of said leaf spring member and at its other end to said supporting member in the region of said one end of said slightly curved leaf spring member, said heat responsive elongated member changing its length depending upon the temperature; and heat-emitting means arranged for heating at least a portion of said heat responsive elongated member whenever required.

6. In a vthermal circuit breaker, a thermally operable movable switch unit, comprising, in combination, a supporting member, a slightly curved leaf spring member mounted at one end on said supporting member; a contact member mounted on the other end of said leaf spring member; a heat responsive electrically conductive elongated member secured at one end to said other end of said leaf spring member 'and at its other end to said supporting member in the region of said one end of said slightly curved leaf spring member, said heat responsive electrically conductive elongated member adapted to be heated by passage of electric current therethrough and to change its length depending upon its temperature; an electric circuit adapted to be connected to the end of said heat responsive electrically conductive elongated member for heating the same by passage of current therethrough; and separate heat-emitting means arranged for heating at least a portion of said heat responsive electrically conductive elongated member whenever required.

7. In a thermal circuit breaker, a thermally operable movable switch unit, comprising, in combination, a supporting member, a slightly curved leaf spring member mounted at one end on said supporting member; a contact member mounted on the other end of said leaf spring member; a heat responsive elongated member secured at one end to said other end of said leaf spring member and at its other end to said supporting member in the region of said one end of said slightly curved leaf spring member, said heat responsive elongated member changing its length depending upon -the temperature; an electrically insulating layer arranged on at least a portion of said heat responsive elongated member; 'and a thin electric current conducting layer arranged on said electrically insulating layer, said conducting layer Operating as heat-emitting means for said heat responsive elongated member.

8. T n a thermal circuit breaker, a thermally operable movable switch unit, comprising, in combination, a supporting member, a slightly curved leaf spring member mounted at one end on said supporting member; a contact member mounted on the other end of said leaf spring member; va heat responsive elongated member secured at one end to said other end of l'said leaf spring member and at its other end to said supporting member in the region of said one end of said slightly curved leaf spring member, said heat responsive elongated member changing its length depending upon the temperature; an electrically insulating layer arranged on at least a portion of said heat responsive elongated member; a thin electric current conducting layer arra'nged on said electrically insulating layer; and means for sending a heating current through said conducting layer.

OTTO WELTER.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1924647 *Feb 14, 1931Aug 29, 1933Service Station Equipment CompThermostat
US2299767 *Feb 2, 1940Oct 27, 1942Joseph SchmidingerThermally operated switch and the like
US2302399 *Feb 13, 1942Nov 17, 1942Gen ElectricThermal relay
DE594744C *Mar 8, 1930Mar 21, 1934Siemens AgUEberstromwaermeausloeser
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2683199 *Dec 6, 1952Jul 6, 1954Gen Motors CorpSafety control switch
US2700084 *Nov 2, 1951Jan 18, 1955Broekhuysen William CElectrical control device
US2706229 *Jul 22, 1954Apr 12, 1955Buske Gilbert ECompensating thermostat
US2726297 *Feb 6, 1953Dec 6, 1955Proctor Electric CoThermal wattage controller
US2727960 *Aug 13, 1953Dec 20, 1955Gutierrez Ruiz HonoratoElectro thermostatic appliance
US2757257 *Dec 22, 1953Jul 31, 1956Michel Vernhes JeanTime-switches for electric circuits, and particularly for signalling circuits
US3340374 *Sep 8, 1965Sep 5, 1967Nikko Denki Seisakusho LtdResistance wire snap acting circuit breaker switch
US5892428 *Jul 27, 1998Apr 6, 1999Hsu; Cheng ChaoThermal actuator
US6075436 *May 18, 1999Jun 13, 2000Hsu; Cheng ChaoCircuit breaker assembly
US6184768 *Dec 19, 1998Feb 6, 2001Cheng Chao HsuThermal actuator
Classifications
U.S. Classification337/141
International ClassificationH01H73/00, H01H73/30, H01H73/08
Cooperative ClassificationH01H73/30, H01H73/08
European ClassificationH01H73/08, H01H73/30