US2727960A

US2727960A - Electro thermostatic appliance

Info

Publication number: US2727960A
Application number: US374082A
Authority: US
Inventors: Ruiz Honorato Gutierrez
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-08-13
Filing date: 1953-08-13
Publication date: 1955-12-20
Anticipated expiration: 1972-12-20

Description

Dec. 20, 1955 u z 2,727,960

ELECTRO THERMOSTATIC APPLIANCE Filed Aug. 13, 1953 INVENTOR 7' H 6? 1 u 12 ATTORNEYS United States Patent O ELECTRO THERMOSTATIC APPLIANCE Honorato Gutirrez Ruiz, Mexico City, Mexico Application August 13, 1953, Serial No. 374,082

4 Claims. (Cl. 200-122) This invention relates to electro-thermostatic appliances.

It is well known that in electric circuits fuses are interposed in the circuits so as to prevent overloading of the circuits or to break the circuit in the event of an overload. While the fuses accomplish the purpose for which they were designed, when a fuse blows out a replacement of the fuse is necessary.

It is an object of this invention to provide an improved circuit breaking means which will eifectively break the circuit when an overload or short circuit occurs, and when the overload or short circuit is eliminated the circuit will be re-established.

Another object of this invention is to provide an improved circuit breaking means which can be finely adjusted to produce the results desired.

A further object of this invention is to provide an improved circuit breaking means which will avoid fire hazards due to overloading or short circuits.

A further object of this invention is to provide a circuit breaking means embodying a glass receptacle filled with inert gas within which a thermostatic switch is positioned. The switch is normally closed and one or more filaments are connected with the switch terminals, and the filaments are of such capacity and resistance as to be normally inactive. When an overload occurs the filaments heat up the interior of the receptacle and the switch, which is of the thermostatic type, moves to a circuit breaking position.

With the above and other objects in view, my invention consists in the arrangement, combination and details of construction disclosed in the drawings and specification, and then more particularly pointed out in the appended claims.

In the drawings:

Figure 1 is a detailed side elevation partly broken away of a thermostatic appliance constructed according to an embodiment of this invention.

Figure 2 is a diagrammatic view of the appliance interposed in an electric circuit.

Figure 3 is a detailed side elevation partly broken away of a modified form of this invention.

Figure 4 is a diagrammatic view of an electric circuit within which the appliance shown in Figure 3 is interposed.

Referring to the drawing, the numeral designates generally a glass bulb having a threaded plug 11 at one end thereof with a center contact 13. The bulb 10 is adapted to be evacuated of air and to then be filled with an inert gas such as nitrogen, argon or the like.

A thermostatic switch generally indicated at 12 is mounted within the bulb 10 and is formed of a pair of

bimetallic bars

14 and 15. Bar 14 is secured to a central support 16 and is electrically connected with the threaded plug 11 as will be hereinafter described. Bar is fixed relative to bar 14 being secured in spaced parallel relation thereto by means of an insulated spacer 17. The upper end of bimetallic bar 14 has a contact point 18 secured thereto and bimetallic bar 15 has threaded into the upper end thereof a screw 19 carrying contact 20 confronting contact 18 and normally disposed in contacting relation with respect to contact 18. A tungsten wire 21 is disposed within the bulb 10 being connected at one end to bimetallic bar 15, and the other end thereof is connected to an upstanding relatively rigid wire or bar 22 which extends downwardly through the lower end of the bulb 10 and is electrically connected with plug 11.

A second tungsten wire 23 is disposed within the bulb 10 and is connected at one end to bimetallic bar 14. The other end of tungsten wire 23 is connected to a relatively rigid wire or bar 24 disposed within the bulb 10 and extending downwardly through the lower end of bulb 10 and connected with the center contact 13. The thermo static appliance hereinbefore described is adapted to be connected in series in an electric circuit embodying a pair of

conductors

25 and 26. The appliance hereinbefore described is connected with either one of the

conductors

25 or 26 and it will be understood that various electrical appliances such as indicated at 27 are connected between the

conductors

25 and 26.

Referring now to Figures 3 and 4, there is disclosed a modified form of this invention wherein the glass bulb 28 is formed with a metal plug 29 and a center contact 30. A pair of

bimetallic bars

31 and 32 are disposed within the bulb 28 which is filled with inert gas. Bar 31 is secured to a central supporting member 33 and bar 32 is fixed adjacent the lower end thereof relative to bar 31 and is electrically insulated therefrom by means of an insulating spacer 34. A tungsten wire 35 is disposed within the bulb 28 and is connected at one end to bar 31. The other end of tungsten wire 35 is connected to an upstanding wire or support 36 which extends downwardly through the bottom of bulb 28 and is connected with threaded plug 29. A second tungsten wire 37 is disposed Within the bulb 28 being connected at one end to the lower end of bimetallic bar 32 and the other end of tungsten wire 37 is connected to an upstanding relatively rigid bar 38. Bar 38 extends downwardly through the bottom of bulb 28 and is connected with center contact 30. The upper end of bar 31 has fixed thereto a contact member 39 and the upper end of bar 32 has threaded therethrough a screw 40 carrying contact 41 which is normally engaged with contact 39.

The bridging tungsten wire 42 is connected between the lower ends of the

bimetallic bars

31 and 32 and is of such capacity as to reduce the amount of current which may be consumed in the event there is a short or an overload in the electric circuit with which this device is connected. The appliance shown in Figure 3 is adapted to be interposed in one of a pair of

conductors

43 or 44. The

conductors

43 and 44 have connected thereto one or more electrical appliances 45.

In the use and operation of this thermostatic switch element the bulb 10 is adapted to be threaded into a socket which is connected with one side of an electric circuit and in series in the circuit. At the time the unit is manufactured the screw 19 is adjusted so that contact will be normally maintained between

contacts

18 and 20 until a predetermined overload or short circuit develops in the electric circuit.

When the overload or short circuit occurs,

tungsten wires

21 and 23 will be abnormally heated, it being understood that the normal load conditions will keep the

tungsten wires

21 and 23 in a relatively cool condition. When

tungsten wires

21 and 23 become unduly heated,

bimetallic bars

14 and 15 will flex so as to separate

contacts

18 and 20 and thereby break the electric circuit to the appliance 27. As soon as the circuit is broken, the

tungsten wires

21 and 23 will cool off and

bimetallic members

14 and 15 will again assume the normal position with

contacts

18 and 20 in contacting relation. This action will produce an interrupted flow of current to appliance 27.

In view of the quick action of the circuit breaking means hereinabove described, in the event there is a short ciredit in the electric circuit, the circuit will be intermitently' broken in such a manner as to prevent a fire occurring or further damage resulting from the short circuit. As soon as the overload has been relieved or the short circuit corrected, the

bimetallic members

14 and 15 will assume their normal circuit closing position.

The device shown in Figures 3 and 4 will operate in a manner similar to that shown in Figures 1 and 2 with the exception that tungsten element 42 is of relatively heavy capacity and is sufiicient to withstand an overload or short circuit of the electric circuit. Tungsten member .42, upon overload of the electric circuit will become heated with

tungsten members

35 and 37 so that the

contacts

39 and 41 will be separated and will be held in separated position as long as tungsten element 42 is also heated. When the short circuit occurs between

conductors

43 and 44 tungsten element 42 will absorb sufiicient electric current so that the amount of current passing through tungsten element 42 to the point of overload or short circuit will be insuflicient to cause a fire.

The devices hereinbefore described are designed for the purpose of taking the place of fuses and will provide a means whereby an electric circuit will be maintained in normally closed position but will be broken as soon as an overload or short circuit occurs. This device is particularly useful in locations where it is desired to limit the consumption of electric current so that only a predetermined amount of electric current will normally pass to an appliance which is connected across the conductors of the electric circuit.

What is claimed is:

v 1. A thermostatic circuit making and breaking switch comprising a base formed of non-conducting material, an elongated bi-metallic bar having one end thereof fixedly secured to said base, a non-conducting spacer member disposed intermediate said first oi-metallic bar and one end of a second bi-metallic bar, means securing said spacer member and said one end of said second lat-metallic bar to said first bi-metallic bar adjacent its said one end, a switch point mounted on said first bimetallic bar adjacent the other end thereof, a second switch point mounted on said second bi-metallic bar, said second switch point confronting said first switch point and normally engaging thereagainst in circuit making position, means for adjusting said second switch point relative to the first switch point, an electrical resistance element positioned proximate to each of said bi-metallic bars in heat exchange relationship, each of said elements having an end thereof electrically connected with their respective proximate bi-metallic oars, and means for connecting the other ends of said elements in a load carrying electric circuit whereby overloading of said circuit draws such current as to heat abnormally said elements which transfer said heat to their respective proximate bars causing the latter to flex thereby separating said switch points and breaking said circuit.

2. A thermostatic circuit as defined in claim 1, and

a third resistance element disposed proximate said bimetallic bars and shunt connected thereacross, said third resistance having a higher resistance than the resistance of said first and second elements.

3. A thermostatic circuit making and breaking switch comprising a base formed of a dielectric material, a bimetallic bar having one of its ends mounted on said base, a second dielectric bar having one end thereof mounted on said first bar, dielectric spacing means disposed intermediate said first and second bars, a switch point contact mounted on each of said bars adjacent their respective other ends, said switch points confronting each other, and normally engaging each other in circuit making position, means for adjusting one of said points relative to the other, a resistance element positioned adjacent each of said bars in heat exchange relation, said elements having one of their ends electrically connected to their respective adjacent bars, and means connecting said other ends of said elements in series in an electric circuit carrying a load.

4. A thermostatic circuit making and breaking switch as defined in claim 3, and a third resistance element disposed proximate said bars in heat exchange relation and shunt connected thereacross.

References Cited in the file of this patent UNITED STATES PATENTS 2,543,707 Prouty Feb. 27, 1951 2,615,146 Macksoud Oct. 21, 1952 2,635,156 Welter Apr. 14, 1953 2,636,077 Jacobson Apr. 21, 1953 2,658,975 Zuckerman Nov. 10, 1953 FOREIGN PATENTS 784,913 France May 6, 1935