US2057093A - Fuse-plug type circuit breaker - Google Patents

Description

Oct. 13, 1936. 1 GE|5S| |NGER 2,057,093

FUSE PLUG TYPE CIRCUIT BREAKER Filed July 6, 1935 5 70 j! ATTORNEY Patented oct. 13, 1936 PATENT .OFI-ICE FUSE-PLUG BREAKEB John Geisslingenlamaica, N. Y., assigner to Die Cast da Forge Corporation, New York, N. Y., a corporation of New York Application July 6, 1935, Serial N o. 30,062

17 Claims.

This invention relates to a fuse-plug type of circuit breaker; that is-to say, a circuit breaker built in the form of and substantially the same size as the present standard fuse-plugs, whereby such fuse-plugs may be replaced by one of the circuit breakers herein disclosed.

' The fuse-plugs used in cut-out panels or boxes in buildings, particularly, homes, have become standardized as to mechanical dimensions, and to l0 make an automatic circuit breakerwhich will fit in the same socket as a standard fuse-plug, presents a real problem, but the advantages of such a fuse-plug type of circuit breaker are several.

It frequently happens. in the operation of electric fiat irons, washing machines and other laborsaving devices now used in the homes, that short circuits or overloads occur which very frequently blow out the fuses, with the result of annoyance to the worker, who is usually inexperienced in the matter of testing to see what fuse or fuses have become disabled, and in the replacement of these devices. In most cases, it happens that no extra fuses are at hand and so the proper size may not be apparent to the one who is to replace the fuse. g5 Hence, an automatic circuit breaker, which is self-indicating and which any one can restore, and which will t in the place of the present standard fuse-plugs, is a decided advantage, assuming of course that the circuit breaker is positive and reliable in its operation.

It is the principal object of my invention to provide a reliable, self-indicating and automatic,

fuse-plug type of circuit breaker to take the place of the present fuse-plugs.

While obtaining this advantage, all the other advantages which flow therefrom will appear to most anyone, after reading the specification taken in connection with the annexed drawing, wherein:

Figure 1 is a sectional elevation on a much enlarged scale of one form of my device.

Figure 2 is a view looking down on the switchplate and parts with the cap removed.

Figure 3 is a bottom view of the switch-plate shown in Figure 2.

Figure 4 is a diagrammatic illustration of the circuit arrangement involved in my device.

Figure 5 is a view similar to Figure l, showing my preferred form of structure.

Figure 6 is a view substantially full-size of the w interior of the plug base, with the switch-plate removed, showing two of the contact members utilized for completing a circuit through the` circuit breaker.

In the various views, wherein like numbers refer to corresponding parts, I is a base member (Cl. 2ND-48) having an integral stem 2 and cap 3 preferably of strong insulating material. The stem 2 carries a metallic shell 4 having the usual formed threads thereon for tting the threads in a fuse-plug socket. The stem 2 also carries a centrally lo- 5 cated cylindrical contact member 5, within which and adjacent the contact end is a core-piece 6. On the other end of the cylindrical member 5, is

a plug 1 of magnetic material having a flange 8 preferably fitting over the end of a cylindrical 10 shell 3 positioned Within the inner periphery of the stem 2. Located between the shell 9 and the member 5, is a pair of windings ID and II. The illustrations in the drawing are merely to show the difference of the windings, without reference to 15 the size or the number of turns, it being kept in mind, however, that the windings are arranged differentially and in proportion to produce the results which will be hereinafter referred to.

Carried within the base I, is a plate I2 pref- 20 erably of good insulating material. Mounted on the plate I2, is a spring I3 which, as shown in Figure 2, is V-shaped, having arms Il and I5 fastened to the plate I in any satisfactory manner as by studs or rivets I6 and I1. On the bottom side of the plate I2, the stud I6 carries a contact I3 of suitable material, which contact is normally in engagement with a contact I9 carried ona strip 2D made of thermostatic metal. The opposite end of the strip 20 from the contact I3 is 30 fastened by a stud 2I to the plate I2, and this stud end is in contact with a spring contact member 22 carried on the base portion and connected to one end of the winding I I. The spring I3 carries a contact 22 of suitable material, which is 35 adapted to operate with a contact 24 carried on a spring 25. The spring 25 is bowed at 25 and the bowed end passes through a slot in the edge of the plate I2 and is preferably fastened on the lower side of the plate I2, as shown in Figure 1. Furthermore, this end of the spring 25 is connected by a suitable connector 21 to the shell 4 of the plug.

Pivotally mounted at 25 on the plate I2, is a lever having one arm 29 extending upwardly and 45 terminating in a catch 30 adapted to engage the free en d of the spring 25. 'I'he other arm 3| of the catch lever extends over the axial center of the plug so as to be engaged by the end 32, preferably of insulating material, of a lever-actuating member in the form of a pin 33, which pin is located in a hole in the plug 1 and extends into the path of movement of the core-piece 5. The stud I1 is adapted to engage a spring contact member 3l that connects with one end of the winding III. 55

It will be noted from Figure 4. that the windings I0 and II have a common Junction point which is connected to the central contact member l.

loosely carried by the spring 2l, is a push button 38 having a stem 3l which passes througha large clearance hole in the spring 2l. The stem 30 is threaded to receive an adjusting means in the form of a nut 31, whereby the location of the stem 36 with respect to the spring 2! may be adjusted. If desired, an additional nut may be used to lock against the nut 31. The button 35 extends through an opening in the cap 3 and is preferably red in color or colored red so as to give a visual indication of the position of the breaker spring 2B. I'he stem 38 is preferably made long enough so that it will contact with the spring I3 to assist in pushing this spring downwardly when the circuit breaker is reset, it being understood that after the catch 30 is engaged by the spring 2l, the button 3l will be held loosely in the spring 25 so that the stem 30 is free from the spring I3, allowing the contacts 23 and` 24 to make positive engagement. l

In order to insure quicker separation of the contacts 23 and 24 at the time the catch 30 is withdrawn, I provide an auxiliary lever 30 pivoted at 39 on the plate I2, one end 40 of the lever 30 extending into engagement with a slot in the turned down end of the spring I3. The other end of the lever 38 preferably rests on a button 4I, preferably of insulating material, carried on the arm 3i of the catch lever, both ends of these levers being in the path of movement of the pin 33. Hence, when the pin 33 is raised, it trips the catch lever from the spring 25 which has considerable tension due to the bow 28 therein. At the same time, the lever 30 is operated so as to produce a quick pull downwardly on the end of the spring I3. Thus, two opposite forces are applied to pull the contacts 23 and 24 apart, with the result that the breaker contacts separate rapidly and the arrangement is such that these contacts separate, as will be seen from Figures l and 5, to a considerable distance; for example, in plugs that I have made, this distance approximates three eighths of an inch.

I have heretofore stated that the windings I0 and II are arranged differentially and in proportion with respect to the number of turns to produce the necessary results. Further in this connection it may be said that the number of turns and size of wire for the windings I0 and Il are such that, for a momentary overload, such as might be caused from the operation of a washing machine or an electric ironer, or electric flat iron,l or a light and brief short circuit, the circuit breaker will not operate by reason of the difference in the amount of flux produced by the windings I0 and Il; but should a heavy short circuit be brought about, then this heavier current passing through the winding I 0 will overpower the effect of the winding II and will immediately actuate the breaker to open the contacts 23 and 24.

On the other hand, if the momentary overload heretofore referred to continues for a short period of time. the thermostat 20 will function to open the contacts 23 and 24, allowing the winding I0 to have its full eiIect to open the circuit breaker as has been described. It is to be understood, as the drawing indicates, that the core piece 6 is separated from the plug 1 by a substantial air gap, so the core piece 3 will be moving rapidly as it approaches the end of the plug 1, thereby causing a rapid movement oi' the catch lever 30 and the auxiliary lever 3l, producing an instantaneous separation of the breaker contacts 2t and 24. As has been heretofore indicated. as the spring 2l moves to open position, the indicating and restoring button 3B moves outwardly through the opening in the cap 3, giving a visual indication that this particular circuit breaker has been operated. The breakermaybereadilyre'setbymerelypushing inwardly on the button 3l. If the short circuit is still on the line. the circuit breaker will be tripped again.

Even with the arrangemmt shown in Figure l, I have produced a circuit breaker which has withstood a most severe test. Por example. it has been tested on a 13o-volt circuit having a capacity of 10,000 amperes, by closing a short circuit by means of a.k switch through the circuit breaker made according to Figure l. and the breaker successfully opened the circuit without damage to itself.

I have thus produced, in the device herein shown and described, a fuse-plug type of circuit breaker, which is positive in its action and which can be used in the same places as the standard fuse-plugs now used.

Certain of the details entering into my construction may be changed somewhat without departing from the spirit of my invention or the scope of the appended claims. f

What I claim is:

1. A fuse-plug type circuit breaker including, base and stern portions, the stem having a centrally located contact member and an exterior metallic screw-threaded shell to engage a cooperative socket. said stem carrying interiorly thereof a pair of windings surrounding a movable core piece, said windings being Joined at one point and this junction connected to said centrally located contact member, a lever-operating member positioned in the path of movement of said core piece, the remaining ends of said windings being connected to contact members within the base portion, a plate carried by the base, said plate carrying a pair of breaker springs having cooperative contacts and a thermostat element carrying a contact and connected through one of said base contact members to the end of one of said windings, a contact on said plate for cooperation with the thermostat element contact and electrically connected to the other of said remaining winding ends through one of said base contacts, and also connected to one of said springs on said plate, the other of said plate springs being connected to said threaded shell, a lever on said plate having one end extending into the path of movement of said lever-operating member, the other end of the said lever having a catch thereon to engage the end of the second of said springs on the plate, a cap for the base, and resetting means located by the cap to move the last-mentioned spring into contact engagement with the first-mentioned spring.

2. A fuse-plug type circuit breaker as set forth in claim l, further characterized in that the breaker springs are positioned on the cap side of said plate and the resetting means comprises a button located in a hole in the top of the cap and having a stem extending loosely through a hole in the spring engaged by the lever catch, said stem having a retaining and locating device thereon.

3. A fuse-plug type circuit breaker as s et forth in claim l, further characterized in that the thermostat consists of a bi-metallic strip mounted on the side of said plate opposite to said breaker springs, and constructed so as to open the contacts in its circuit on continued now of current therethrough.

4. A fuse-plug type circuit breakras setv forth in claim 1, further characterized in'thatone of being mounted on the plate between the arms of said V and being formed in a loop over the V springs, its free end being engaged by saidl lever catch.

5. A fuse-plug type circuit breaker as set forth in claim 1, further. characterized in that the said windings are so electrically proportioned a'nd differentially connected that for short time overloads the circuit breaker will not open but the thermostat will open the winding in its circuit if the overload continues. allowing the other winding to actuate said core piece to separate the breaker springs.

6. A fuse-plug type circuit breaker as set forth in claim l, further characterized in that a second lever is located so one end thereof is actuated by said lever-operating member, while the other end of said second lever engages one of said breaker springs so as to pull the spring away from its cooperative spring when the same is released by said catch.

7. A fuse-plug type circuit breaker including, base and stem portions, the stem having contact members to engage cooperative members in a socket, a pair of diherentially connected windings housed within the stem and a junction of said winding being connected to one of the plug contact members, a movable core piece embraced by said windings, an operating member in the path of movement of said core piece, a plate carried by said base, a pair of breaker springs mounted on the plate but insulated from each other and each carrying cooperative contacts, a cap for the base, a resetting button having a stem adjustably engaging one of said springs, the button protruding through the cap and the spring being connected to one of the plug contact members, a lever having a catch to engage the end of the last-mentioned spring, the opposite end of the .lever extending into the path of movement of said lever-operating member, a thermostat device carried by said plate and having contacts connected into circuit with one of said windings, while the other winding is' connected to one of the thermostat members and to the breaker spring which cooperates with the catch spring as described.

8. A fuse-plug type circuit breaker as defined in claim '7, further characterized in that-a second lever is provided, one end being moved by the movement of said lever-operating member, while the other end engages the breaker spring which cooperates with the breaker catch spring for the purpose described.

9. A fuse-plug type circuit breaker as defined in claim 7, further characterized in that the push button stem goes through an opening in the catch spring and extends a length suiiicient to engage the other breaker spring to press it in a direction away from the catch spring as and for the purposes described.

10. A fuse-plug type circuit breaker as defined in claim '1, further characterized in that the leveroperating member is in the form of a non-magnetic pin seated on the end of said core piece,

at least its end -6118181118 the catch lever being of insulating material.

11. A fuse-plug type circuit breaker as denned in claim '7, further'characterized in that the plug center" contact member is a tube preferably nonmagnetic-,the-core piece being normally held by the catch lever at the contact end of the tube, while a' plug of magnetic material is located in the upper end of the tube but leaving a substa'ntlal air gap between the plug and the core piece, and further characterized in that a shell of magnetic material encloses said windings, said shell having a magnetic return member at the contact end of the plug.

12. A fuse-plug type circuit breaker to ilt standard fuse-plug sockets including a base of insulating material having a stem exteriorly carrying a threaded contact shell and a removable cap of insulating material, a central contact for the plug comprising a tubular metallic member, a core piece normally located in one end of said tubular member, a magnetic plug member positioned in the other end of the tubular member leaving an air gap between it and the core piece, a magnetic return shell within the inner wall of the stem and contacting with said plug, a pair of differentially wound windings within the return shell, a plate of insulating material carried by the base above the stem, a pair of breaker springs on the plate having cooperative contacts, a lever mounted on the plate and having a catch at one end to engage one of said springs, a pin extending through said plug member into cooperative position with the other end of said lever and said core piece, a thermostat device carried on said plate and connected in circuit with one of said windings, the other of which is connected in shunt to the thermostat, while said catch spring is connected to said plug shell contact, and a resetting button operatively attached to said catch spring and extending through the cap for setting said breaker.

13. A fuse-plug type circuit breaker as defined in claim 12, further characterized in that a second lever is carried by said plate, one end of the lever engaging the second breaker spring, while the other end of the lever is moved by said pin as and for the purposes described.

14. A fuse-plug type circuit breaker to iit standard fuse-plug sockets including, a base and a removable cap, both of insulating material, a plate of insulating material on the base housed by the cap, a pair ot breaker springs having cooperative contacts, a setting device carried by one of the springs and extending through the cap, a thermostat devicecarried on the plate, a pair of diilerentially wound windings located in the stem, a movable core piece located within the windings, a lever having a catch at one end to engage said spring carrying the setting device, an operating member engaging the other end of the lever and actuated by said core piece, said windings, breaker springs and thermostat device being connected to respond to the iiow of current substantially as described.

15. A fuse-plug type circuit breaker as dened in claim 14, further characterized in that said catch lever is carried on said plate and a second lever is also carried on the plate, one end of the second lever engaging the other of said breaker springs, while the other end of the second lever is actuated by the movement of said operating member.

16. A fuse-plug type circuit breaker to fit standard fuse-plug sockets including, a base and a removable cap. both o! insulating material. eir- .cuit breaker springs housed within said cap. a lever i'or catching and holding one ot the springs in contact with the other, means extending withoutthecapiormovingsaidsprinzstoclosedposition. said base havin: a stem carryins socketensasins contact members. a pair ot diiienntially wound windings within the stem, a movable core piece located near the axial center of the windings. means actuated by the core piece to move said lever to release said sprinl. a thermostat device within the base. the windinls. breaker springs and thermostat device bein: connected to respond to the iiow of current substantially as described.

' by the core piece.

JOHN GUBBLINGER.

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