US2059985A - Circuit breaker - Google Patents

Description

Nov. 3,1936. w- H. FRANK ET A1.

C IRCUI T BREAKER Original Filed Jan. 3,. 1935 INVENTORS /f/d MMUJ, if

Patented Nov. 3, 1936 UNITED STATE cracm'r nimma William H. Frank and Joseph Messing, Detroit, Mich., assignors to Bulldog Electric Products Company, Detroit, Mich., a corporation of West Virginia Original application January 3, 1933, Serial No. l ,649,983,lk now Patent No. 1,982,289, November Divided and this application October 26, 1934, Serial No. 750,161

6 Claims. (Cl. 20o-121) This application discloses a circuit breaker unit and is a division of our copending application Serial No. 649,988, filed January 3, 1933, now Patent No. 1,982,289 of November 27, 1934, class 200, sub-class 116.

One principal object is to provide, in connection with circuit breakers, means for indicating the condition of the breaker and/or condition of the circuit controlled thereby. More specifically, it is aimed to provide novel constructions and combinations including heads .for enclosing the circuit breaker proper equipped with indicating devices such as lamps, etc., which may be lit upon changes in the condition of the breaker and/or the controlled circuit.

. It is contemplated at the present time to provide for a standard form of circuit breaker, interchangeable and convertible heads which may be made from a single blank, the blank being con-` vertible, as desired, into a simple, breaker-enclosing head, or into a head which not only encloses the breaker parts but which also can be equipped with indicating parts.

In one design, theindicating parts will give one indication when the breaker has been released on overload and will give a different indication under different conditions. `In a. second design,` the indicating parts will produce three different indications, one, for an overload release produced by a short circuit, another, for an overload release produced by a relatively light overload, and a third, for other conditionsof the circuit. This type of indicating means is particularly desirable In that it not only indicates the existence of an abnormal condition in the circuit but it also indicates the nature of the abnormal condition. It is contemplated to have the indicating means in the form of a lamp or`tube so connected that it will be dark when the breaker is closed, and glow when it is open, as contra-distinguished from prior artfconstructions, wherein the lamp or tube is so connected that it will be dark when the breaker is open and glow when it is closed. l

Further, in the last mentioned design, the indicating means may be sotconstructed thatl though the indications on overloads are different, depending upon the nature of the overload, they are both so different from the indication produced by a normal condition of the circuit, that though they may readily be distinguished from each other, they may also be distinguished from the normal load indication. In a preferred embodiment, following this idea, where the indicating means isin the nature of a neon tube, the design is such that the neon tube will burn brightly on short circuit, dimly on light overload, and not at all on normal load.

Further, the indicating means of the last mentioned design permits the operator to tell at a glance whether it is safe to' close the breaker,

once it has tripped. For example, if the lamp burns brightly as on a short circuit overload, the operator will immediately know that itis dangerous to close the breaker. However, if the lamp is burning dimly, as on light overload, the operator will know that it is safe to close the breaker.

A further object is to provide an indicating means wherein a neon tube is employed as the indicating element, this type of indicator permitting novel connections, ufor results outlined in the foregoing. i i

Still further objects will be readily apparent to those skilled in the art upon reference to the following detailed description of embodiments of y Y circuit breakers, the same to be read in connection vwith the appended drawing. Referring to this drawing, it will be seen that Figures 1 and 2 are cut away elevation views of a circuit breaker provided with an indicating "means, the breaker being shown in On and overload OE positions, respectively.

Figures 2a, 2b and 2c show schematically the device of Figures 1 and 2, and two variations thereof.

Circuit indicating means |43, aflexible jumper |43a,a thermal warping element T4, and a jumper |43b. Arm |43 jis journalled at`l44, to frame |45, and may be moved by links HIL-|48, connected by an axle pin |49, links |48 being connected by pin |50 to a member 5| journalled in frame |45 at |52.

Pin |44 also journals the operating arm |53 to the upper end of which is secured the arcuate piece |55 formed with a handle |56 by means of which the arm |53 can be moved manually, an upper part |58 of arm |53 is connected by coil springs |59 to pin .|49 and these springs form the operating springs of the device.

For holding the pin |49 down, on normal loads, there is provided a pawl |60, journalled at I6! and restrained by the warping element T4. It will be understood that on overload, the latter warps to the right, releasing pawl |60, which in turn releases pin |49, permitting it to be pulled upwardly, and to the left by springs |59.

It will also be understood that when handle |55 is moved to the right, for switch Oli position, pin |49 is moved to the'right and upwardly, but does not move to the left.

'I'he construction thus far described is no part of the present invention, except insofar as-lt relates to the circuit indicating means provided for the device and now about to be described.

For covering those parts of the breaker proper left exposed by the open top of the base |40, there Yeo ves

may be provided one of two interchangeable and convertible heads, one of which may be equipped with circuit indicating means, (the head shown), and the other of which may be nothing more than a closure.

Both of the heads are substantially alike, differing only in details, and are made from a blank in the form of an insulating cupped block |88 provided with end bosses |8| in which are tapped bushings (not shown); a central cut out |82 in which moves the arcuate piece |55 and the handle |56; a boss |83 provided with a bore |84, closed by a "knockout, (not shown), but positioned at the upper end of bore |84; and a knockout", (not shown), normally closing the opening at |84a.

When the blank is not lto be equipped with circuit indicating elements, the knockouts `are left in place, and the blank forms a head that is completely closed, exceptfor cut out |82.

When the blank is to be equipped with the circuit indicatingelements, the knockouts" at bore |84 and opening |84a. are removed and a tell tale lamp |85 is positioned and sealed in bore |84, being visible through the opening left by the removed knockout". One lead of the lamp is connected to a screw |88 in yboss |8| by a flexible lead |81, and the other leadis connected to a screw |88 in boss |83, as shown.

In the boss |8| near boss |83, there is mounted a screw |89 which clamps in place two resilient contact leaves |90 and |9|, the former of which has a forked end straddling the sides of the operating arm |53 and the other` parts of the breaker, the tines of the forked end having insulation pieces |92 overlying the extended ends of the linkage pin |49, and positioned to be engaged thereby.

The spring leaf |9| is bent to engage and make electrical contact with the jumper |4|a of the breaker. l

A conductor Aend |93 passed through opening |84a is held in place by screw |88 and `connects the lead |81 to that side of the line opposite from the line connected to the'jumperl |4|a.

It will be observed at this time that spring leaf |90 is so tempered that it normally is spaced Vfrom The head may be fitted onto a breaker-equipped base, with its leaf 90 strad'dling the breaker parts, -and with its leaf |9| engaging jumper |4Ia, 'this being accomplished without alteration of the base Under normal load conditions, not engage the ends |92 ordeal' I or the breaker. thepin |49 will |90 anduwill not move the latter towards screw |88, thisbeing true even as the pin |49 is moved to and from its On" and Oil positions.

When an overload occurs, however; pin |49 will move upwardly andto the left and will engage ends |92 of leaf |90,v moving the latter upwardly so that it will engage screw head |88. Lamp |85 will thus be placed in circuit with the line conductors and will light, indicating that the circuit breaker has been released on overload.

It will be observed that the lamp is not in series with the breaker-load circuit, but is in multiple therewith, and is mechanically, rather than electrically, connected to the breaker.

In Figure 2a., which shows the device of Figures 1-2 schematically, it will be seen that the circuit through lamp |85 is closed when the breaker trips, as an overload, due to the engagement of pin |49 and leaf |90. At all other times the lamp circuit is open and the lamp does not light.

Diierent visual indicating arrangements are contemplated, as alternative uses of the devices and mechanisms disclosed in Figures 1 2, and these are schematically indicated in Figures 2b and 2c.

In Figure 2b, the lamp 380 is shown as of the vneon tube type and it is shown as connected in series with the load linev through the medium of a spring contact 30 secured to boss |8| by screw |86 and adapted to engage jumper |43b when the head is placed on the base. Otherwise, the parts are like those shown in Figure 2a. It will be seen that the lamp circuit is closed only when the breaker is tripped by an overload or short circuit, the lamp circuitV in this case including the load device whose short circuit caused breaker trip.

In Figure 2c, the lamp 300 is also shown as of the neon tube type and it is also shown as connected in series with the load line through a contact 30|, etc. The leaf 3|0, however, is bent downwardly as shown, to be engaged by contact arm |43, rather than by pin |49, and is insulated from arm |43. Accordingly, the lamp circuit is closed when the breaker is opened,v whether by a normal switch opening operation, or by an abnormal short circuit condition.

From the foregoing, it can be seen that it is possible to obtain a novel visual indicating effect from the device. For example, assume the lamp to be so designed as to burn brightly when in series with an extremely low resistance (short circuit), to burn dimly when in series with a rei sistance of medium strength (light overload) and not to burn -at all when in series with a high resistance (normal load), or an infinitely great resistance (open. circuit). Under such conditions the lamp will burn brightly on switch opening due to a short'circuit; will burn dimly on switch opening due to a light overload, and will not burn at all on normal switch opening. A glance at a lighted lamp will therefore reveal not only the `fact that the breaker has tripped, but also the cause of the breaker trip. that' is to say, will reveal not only that the breaker has tripped, but will also reveal whether a. short circuit (bright) or a light overload (dim) caused the breaker to trip.

Further, a construction of this character may be used to indicate to the operator whether or not it issafe to close the breaker after trip. 1f the breaker has tripped, but the lamp is out, the

'operator will know that the circuit back of the breaker was opened after the event that caused trip, and that it is safe to close the breaker. Also, if the breaker has tripped, and thelamp is burning dimly, the operator will know that the circuit contains a light'loverload, and thatvthe breaker may be closed safely. But if the breaker has tripped, and the lamp is burning brightly, the operator will know that the 'circuit contains a short circuit or a heavy overload and that it would be unsafe to close the breaker.

. In further explanation of the foregoing, the

following discusion as to the characteristics of neon tubes ,will be given. The successful operation of a neon tube or lamp requires that a re sistance be interposed in series therewith. Now, by varying the interposed series resistance, the sensitivity and lighting characteristics of the lamp can be varied to a considerable extent. For example, the lamp can be designed to operate in the manner described above by determining properly the interposed resistance. y

Further, vwhere the range between the load circuit resistance on short circuit and the load circuit resistance on light overhead, etc., for the above described operation is not great, it is mcontemplated to use, in conjunction with the neon tube, a well known bridge .type circuit, in which case the tube would indicate, by its different lightings, not the differences in the load circuit `resistances, but the diiference in ratios of the load circuit resistances. This arrangement offers an extreme sensitivity to the indicating neon tube.

Further, while it is preferred to use as the indicating means, a neon tube, which offers the advantages of low cost, long life, and low current consumption, it is possible to use ordinary incandescent lamps, with relatively satisfactory results.

It is further contemplated to combine the neon tube with rthe breaker in such a way that one of the terminals of the tube is connected to the live conductor on the live side Vof the breaker. In such'a" combination, the neon tube will glow dimly in the event that the breaker is open, or in the event that there is an open circuit on the load side of the breaker, and the neon tube will burn brightly in the event of -a short circuit or heavy overload. The difference in glowings of the tube' will indicate the nature of the circuit line back of the breaker, as can be observed.

'It will also be seen that in the vconstructions shown, the tube or lamp is dark when the circuit is closed or live, and glows when the load circuit is open or dead, as contra-distinguished from constructions of the prior art, wherein the lamp is connected across the breaker so as to be dark when the load circuit is open or dead, and glow when the load circuit is closed or live. In the last mentioned type of construction, an operator, seeing the lamp dark, will rely upon it as an indication that the circuit is open or dead.

This may, however, be a misreliance, since the lamp may be dark, due to the lamp having been burnt out or become disconnected, even though the circuit be alive, and this misreliance may lead to serious injury. In our construction, however, an operator, seeing the lamp dark, will believe the circuit to be closed or alive, and will act accordingly. Thus, even if the lamp be dark be' cause of lamp failure, etc., rather than because of the circuit being alive, the operator, though he be misled as to the cause, will not be misled to his injury. I-Ie will determine the cause of the lamps being dark and, having satisfied himself, may then proceed to work on the circuit.

Now, having described embodiments of circuit breakers, selected by way of example, reference will be had to the appended drawing which determines the scope of the monopoly desired, it being understood that, except as set out in the claims, the monopoly is not to be limited to the embodiments disclosed.

We claim:

1. A combined switch and circuit breaker device of the operating type manually operable for normal switching and operating automatically for overload release, the breaker having a line shunting the breaker controlledl line and containing an auxiliary switch and an indicator energizable by the breaker controlled line energy when the auxiliary switch is closed, the auxiliary switch being constructed and arranged to be open normally and during manual switching operation and being constructed and arranged to be closed automatically by and upon release operation of the breaker and only then to energize the indicator.

2. A combinedv switch and circuit breaker denvice of the operating type manually operable for normal switching and operating automatically for overload release, the breaker having aline shunting the breaker controlled line and containing an auxiliary switch and an indicator energizable by the breaker controlled line energy when the auxiliary switch is closed, the auxiliary switch being constructed and arranged to be open normally and during manual switching operation and being constructed and arranged to be closed automatically by and upon release operation of the breaker and only then to energize the indicator, the shunt line, the switch, and the indicator being formed as part of a removable cover of the device.

3. The combined switch and circuit breaker device of the operating type manually operable for normal switching and operating automatically for overload release, the breaker havingan indicator energizable by the breaker controlled line energy, the indicator being constructed and arranged to be deenergized .normally and during manual switching operation and being constructed and arranged to be energized automatically by and upon release operation of the breaker and only then.

4. A construction of the character described in claim 3 wherein the indicator is formed as part of a removable cover of the device.

5. A combined switch and circuit breaker device of the operating type manually operable for normal switching and operating automatically for overload release, the breaker havinga line shunting the breaker controlled line and containing an auxiliary switch andan indicator energizable by the breaker controlled line energy when theiauxiliary switch is closed, the auxiliary switch being constructed and arranged to be open normally and during manual switching operation and being constructed and arranged to be closed automatically by and upon release loperation of the breaker and only then to energize the indicator, the latter being arranged to give a different iindication when energized by breaker release following moderate overload from what it gives when energized by breakerrelease following excessive overload.

6. A combined switch and circuit breaker device of the operating type manually operable for normal switching and operating automatically for overload release, the breaker having an indicator energizable by the breaker controlled line energy, thev indicator being constructed and arranged to be deenergized normally and during manual switching operation and being constructed and arranged to be energized automatically by and upon release operation of the breaker and only then, the latter being arranged to give a different indication when energized by breaker release following moderate overload from what it gives when energized by breaker release following excessive overload. Y

WILLIAM H. FRANK. JOSEPH MESSING.

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