Remotely controllable circuit breaker

An improved remotely controllable circuit breaker comprises a manually operable switching mechanism for opening and closing a single set of first and second contacts, a trip mechanism for opening the contacts upon occurrence of predetermined overload current conditions, and a remotely controllable switching mechanism for selectively opening and closing the contacts in response to a control signal remote from the breaker. The manually operable switching mechanism includes a movable contact arm carrying the first contact to be brought into and out of contacting engagement with the second contact by manipulation of a manual handle. The second contact is operatively connected to the remotely controllable switching mechanism to be driven thereby for movement between an operative position where the second contact is engageable with the first contact and an inoperative position where it is prohibited from being engaged with the first contact independently of the position of the first contact. Accordingly, the remotely controllable mechanism can be entirely isolated from the manually operable switching mechanism when the former is responsive to the remote control signal for bringing the second contact into its inoperative position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention is directed to a remotely controllable circuit 
breaker, and more particularly a remote controllable circuit breaker with 
a single set of breaker contacts which are forcibly opened and closed by a 
control signal remote from the circuit breaker independently of switching 
action by a manual handle of the breaker. 
2. Description of the Prior Art 
Circuit breakers of the above type which permit an remote control operation 
of opening the breaker contact are known in the art. Such a circuit 
breaker, for example, is described in U.S. Pat. No. 4,223,288. The circuit 
breaker utilizes a remotely controlled solenoid which, in response to a 
control signal from a location remote from the circuit breaker, actuates a 
movable contact arm carrying a movable contact away from a cooperative 
stationary contact for separation of the breaker contacts. The movable 
contact arm is operatively connected to a manually operated handle and an 
over-center tension spring to constitute a manually operable switching 
mechanism which, by the manipulation of the handle, is articulated with an 
over-center spring action between its ON position of closing the contacts 
and OFF position of opening the contacts. Said remotely controlled 
solenoid has an armature in abuttable engagement with the movable contact 
arm so that, when the solenoid is energized responsive to the remote 
control signal, the armature pushes the movable contact arm in the 
direction of disengaging the movable contact from the stationary contact 
against the biasing force of the over-center action spring. In this sense, 
the solenoid is to be additionally included or linked into the manually 
operable mechanism so as to add to complexity thereof and consequently 
render the fabrication thereof rather complicated. 
In the meanwhile, it is quite possible that a consumer not knowing of the 
load interruption by such remote control signal tries in confusion, to 
uselessly manipulate the manual handle in an attempt to restore the load 
in series with the breaker. Such manipulation of the handle will naturally 
involve the movement of the movable contact arm between its ON condition 
and OFF condition with the over-center action of the spring included in 
the manually operable switching mechanism. Accordingly, with the above 
arrangement of actuating the movable contact arm linked to the handle and 
spring for separation of the breaker contacts by the remotely controlled 
solenoid, the solenoid cannot avoid being struck by the movable contact 
arm in its forward stroke from the OFF condition to ON condition due to 
the above handle manipulation by the unknowing consumer. With this result, 
the solenoid will suffer from the hammering action by the movable contact 
arm which action may damage the solenoid or cause the armature of the 
solenoid to bounce from its position of forcibly opening the breaker 
contacts into the position of momentarily closing the contacts, thus 
failing to stably keep the breaker contacts opened and rendering the 
operation of the remote controlled solenoid less reliable. To this end, 
the above prior circuit breaker has to include a separate latch means 
which is combined with the solenoid for mechanically holding the solenoid 
armature in the fixed position of opening the breaker contact so as not to 
be affected by the above hammering action, which further complicates the 
construction of the circuit breaker. 
SUMMARY OF THE INVENTION 
The present invention has been made in view of the above problems and 
therefore provide an improved circuit breaker in which a remotely 
controllable mechanism when actuated responsive to a remote control signal 
for separation of the breaker contacts can be entirely isolated from a 
manually operable switching mechanism including a manual handle and a 
movable contact arm such that the former mechanism will be free from an 
accidental manipulation of the latter mechanism by a unknowing consumer, 
ensuring reliable operation of maintaining the breaker contacts to be 
opened due to the remote control signal. The remotely controllable circuit 
breaker in accordance with the present invention has a single set of first 
and second breaker contacts and a manually operable switching mechanism 
for manually opening and closing the breaker contacts, which mechanism 
includes the manual handle and the movable contact arm carrying the first 
contact to be movable between the ON condition and OFF condition for 
bringing the first contact into and the out of contacting engagement with 
the second contact in response to the manipulation of the handle. A trip 
mechanism is operatively connected to the manually operable switching 
mechanism so as to open the breaker contacts upon the occurrence of a 
predetermined fault currents flowing through the breaker. The remotely 
controllable switching mechanism is included in the circuit breaker to 
open and close the breaker contacts in response to a remote control signal 
independently of the operation of the manual switching mechanism. An 
important novel feature of the present invention resides in the fact that 
the second contact is movable between an operative position where it is in 
contacting engagement with the first contact of the movable contact arm in 
its ON condition and an inoperative position where it is kept away from 
the first contact independently of the condition of the movable contact 
arm to disable the contact closing, and in that said second contact is 
operatively connected to said remotely controllable switching mechanism in 
such a way as to be moved between the operative and inoperative position 
by the latter receiving the remote control signal. Thus, the remotely 
controllable switching mechanism is operatively connected only to the 
second movable contact and not to the manually operable switching 
mechanism including the movable contact arm and the manual handle, such 
that the former mechanism will be kept free from being influenced by the 
action of latter mechanism which may be likely to be actuated by a 
consumer not knowing of the remote control responsive interruption of a 
selected load in series with the circuit breaker in the event of that 
interruption. With this result, the remotely controllable switching 
mechanism can be protected from being influenced by the accidental 
actuation of the manually operable switching mechanism so that it will not 
be damaged thereby and that it can keep the breaker contacts opened or 
closed in a reliable manner without resorting to any special guard means 
protecting the remotely controllable switching mechanism against the above 
accidental actuation of the manual switching mechanism during the remote 
control signal responsive interruption of the breaker. 
Accordingly, it is a primary object of the present invention to provide a 
remotely controllable circuit breaker which is reliable in operation and 
simple in construction. 
In preferred embodiments, said remotely controllable switching mechanism 
comprises a polarized electromagnet having an armature operatively 
connected to said second contact for movement thereof between its 
operative and inoperative positions. The permanent magnet means attracts 
the armature in the direction of moving the second contact to the 
operative position of enabling the contact opening and closing by the 
manual switching mechanism. Upon energization of the electromagnet in 
response to the remote control signal, the armature is magnetized to have 
a magnet flux which opposes and overpowers the flux emanating the 
permanent magnet means, so that the armature is operated to move the 
second contact into the inoperative position. Thus, with the use of the 
polarized electromagnet as the remotely controllable switching mechanism 
for contact separation, the circuit breaker of the present invention can 
enjoy the benefit of polarized construction such as being operated at a 
lesser power requirement for remote control signal responsive separation 
of the contacts as compared to the general electromagnet construction 
without the permanent magnet, and providing higher response sensitivity. 
It is therefore another object of the present invention to provide a 
remotely controllable circuit breaker operable at a lesser power 
requirement with higher response sensitivity. 
In addition, the above polarized electromagnet is designed to stably hold 
the armature and therefor the second contact in either or both of its 
operative and inoperative positions, i.e., to have monostable operation or 
bistable operation. In one or more embodiments, the monostable operation 
is given to the polarized electromagnet such that the second contact is 
only stable at either of its operative or inoperative position, whereby 
the second contact is attracted upon deenergization of the electromagnet 
toward one of its positions selected depending upon an intended use of the 
circuit breaker. In other embodiments, the polarized electromagnet has 
bistable operation to hold the second contact both at the operative and 
inoperative positions upon deenergization of the electromagnet so that the 
second contact is kept at its positions without requiring continued 
energization of the electromagnet. 
In the present invention, a novel and useful construction of the polarized 
electromagnet is disclosed to be effective in obtaining a compact 
arrangement as well as in reducing the leakage of the magnetic flux from 
the permanent magnet to thereby increase operation efficiency. The novel 
electromagnet construction comprises an axially movable armature to be 
connected to the second contact for movement thereof, a winding 
surrounding the armature, first and second U-shaped yokes mounted against 
the opposite sides of the winding with the central portion of each yoke in 
parallel relation with the length of the armature, and the permanent 
magnet means disposed between the center portions of the first and second 
yokes to polarize them in opposite polarity. The legs of the first yoke 
are located at positions axially outwardly of the armature ends to define 
individual outer pole members, while the legs of the second yoke are at 
positions axially inwardly of the outer pole members but outwardly of the 
ends of the winding to define individual inner pole members each of which 
is cooperative with the adjacent outer pole member to define an air gap 
within which the axial end of the armature is positioned so that the 
armature is axially movable in response to the excitation of the winding 
under the influence of the permanent magnet means. With this arrangement, 
the first and second yokes can be spaced laterally by a maximum distance 
within a minimum lateral dimension of the electromagnet assembly, thereby 
reducing the leakage or ineffective magnetic flux of the permanent magnet 
means acting between the center portions of the yokes while centralizing 
an effective magnetic flux between the axially aligned outer and inner 
pole members to assure an effective armature operation due to the flux of 
the permanent magnet means. The above electromagnet construction is 
particularly suitable for obtaining a bistable operation which allows the 
armature to be locked in both positions at each of which the armature has 
its axial ends in proximity to the outer and inner pole members to 
complete the magnetic circuit of the permanent magnet flux. 
It is therefore a still further object of the present invention to provide 
a remotely controllable circuit breaker in which the remotely controllable 
switching mechanism is made of a polarized electromagnet of compact 
construction and efficient electromagnetic operation. 
The above remotely controllable switching mechanism can be successfully 
combined with a manually operable switching mechanism of different types, 
one with an over-center action spring for effecting quick-break, 
quick-make contact operations and others with a spring-loaded linkage for 
effecting quick-break, delayed-make contact operations. 
In preferred embodiments, the second contact is held on a contact carrier 
which has a first pivot axis for rotation thereabout and a second pivot 
axis connected to the output end of the remotely controllable mechanism so 
that the second contact when actuated by the latter moves along an arcuate 
path about the first axis into and out of contacting engagement with the 
first contact on the movable contact arm. This is advantageous in that an 
optimum travel or separation distance of the second contact from the first 
contact can be obtained with a limited movement of the output end of the 
remotely controllable switching mechanism. 
It is therefore a further object of the present invention to provide a 
remotely controllable circuit breaker in which the travel distance of the 
second contact can be set at an optimum value with a limited amount of 
movement of the output end of the remotely controllable switching 
mechanism selected. 
The present invention further discloses a unique and advantageous 
construction feature of an arc extinguishing chute to be incorporated into 
the circuit breaker. The arc chute includes an arc runner which is 
electrically connected to the second contact and is in a closely spaced 
relation to a contact plate carrying the second contact. The contact plate 
is arranged in generally parallel relation to the movable contact arm 
carrying the first contact in its closed or ON condition and passes the 
current therethrough toward the contacts in the opposite direction to the 
current passing in the movable contact arm so as to produce in the 
vicinity of the contact an electromagnet force which acts on a possible 
arc drawn between the contacts upon separation thereof to transfer one end 
of the arc from the second contact to the arc runner. Once this occurs, 
the arc proceeds along the arc runner as the movable contact arm moves 
toward its OFF condition and is finally guided into a stack of spaced 
metal plates to be extinguished thereat. With this result the arc drawn 
between the contacts can be readily transferred from the contacts and 
extended for enhancing the extinction of the arc and thus well protecting 
the contacts against the arc, which is therefore a further object of the 
present invention. 
As an additional feature of the present invention, the circuit breaker is 
provided with an indicator which is responsive to the remote control 
signal to provide a visual indication of the actuation of the remotely 
controllable switching mechanism. Thus, a consumer looking at the side of 
the breaker can readily acknowledge the remote control signal responsive 
circuit opening or closing. 
These and other objects and advantageous features of the present invention 
will be more apparent from the following detailed description of the 
preferred embodiments when taken in conjunction with the attached drawings 
.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
First embodiment &lt;FIGS. 1 to 6&gt; 
A remotely controllable circuit breaker according to a first preferred 
embodiment of the present invention comprises a housing 1 of electrically 
insulative material in which a manually operable switching mechanism 20 is 
provided to manually open and close a single set of first and second 
breaker contacts 11 and 12 by manipulation of a manual handle 21 mounted 
on a handle pivot 2 of the housing 1 for pivotal movement thereabout. The 
housing 1 includes a side cover (not shown) and is separated by a 
partition rib 3 laterally into two compartments 4 and 5, one for receiving 
the manually operable switching mechanism 20 and a trip mechanism 30 which 
opens the contacts 11 and 12 upon occurrence of predetermined overload 
current conditions and the other for receiving a remotely controllable 
switching mechanism 40 which is responsive to a remote control signal fed 
from a location remote from the breaker for opening the contacts, such 
remote control responsive contact opening operation overriding the manual 
switching operation to forcibly open the contacts 11 and 12. 
Said manually operable switching mechanism 20 is of conventional 
arrangement including the manual handle 21, a movable contact arm 22 
carrying the first contact 11, and an over-center action spring 23 which 
effects the closing and opening of the contacts in quick-make, quick-break 
fashion. The first contact 11 is electrically connected through the 
movable contact arm 22, a braid 13, and bimetallic strip 31 to a line 
terminal 14 at one end of the housing 1, while the second contact 12 is 
electrically connected through a contact carrier 15 thereof, braid 16 to a 
female stab type line terminal 17 at the other end of the housing 1. The 
movable contact arm 22 has its upper end in pivotal abutment with the 
lower end of the manual handle 21 to be operatively connected thereto so 
that it is movable in response to the manipulation of the manual handle 21 
between an ON condition where the first contact 11 is in electrically 
contacting engagement with the second contact 12, as shown in FIG. 1, and 
an OFF condition where the first contact 11 is away from the second 
contact 12 for separation of the contacts, as shown in FIG. 3. The 
over-center action spring 23 extends between the movable contact arm 22 
and a cradle 24 pivotally supported at its end to a cradle pivot 6 in such 
a way as to have its line of action in the direction of biasing the 
movable contact arm 22 and therefore the first contact 11 carried thereon 
into and out of contacting engagement in an over-center manner as the 
handle 21 is manipulated to be pivoted to its counterclockwise-most ON 
position and clockwise-most OFF position, respectively. 
Also mounted in the compartment 4 of the housing 1 is the trip mechanism 30 
which is operatively connected through the cradle 24 to the above manually 
operable switching mechanism 20 in order to separate the contacts 11 and 
12 upon the occurrence of overload current conditions. The trip mechanism 
30 is also of conventional arrangement which includes a trip arm 32 and 
said bimetallic strip 31 with a magnet 33 fixed at a portion thereof. The 
bimetallic strip 31 is fixed at it upper end to one end of a strap 18 
which connects at its other end with a wire-gripping screw 19 of said line 
terminal 14. The trip arm 32 extends in generally parallel relation to the 
bimetallic strip 31 and is pivoted at its upper end to a trip axis 7 and 
is urged by a torsion spring 34 wound about that axis in a clockwise 
direction as viewed in the figures. The lower end portion of the trip arm 
32 is bent upwardly into a U-shaped hook 35 engageable with the lower end 
of the bimetallic strip 31. Formed in the trip arm 32 at intermediate 
portion thereof is a latch hole 36 in which a latch end 25 of said cradle 
24 engages to retain the cradle 24 in position against the biasing force 
of the over-center action spring 23. Upon occurrence of lesser overload 
current, the bimetallic strip 31 is resistively heated to deflect the 
lower end thereof to the right for engagement with the hook 35, thereby 
causing the trip arm 32 to move in the counterclockwise direction so as to 
unlatch the cradle 24, with the result of which the cradle 24 is freed to 
rotate under the urgence of the over-center action spring 23 into a 
tripped position as shown in FIG. 4 so as to rapidly move the movable 
contact arm 22 away from the second contact 12 with the over-center action 
of the spring 23 for quick-break of the contacts. Said magnet 33 fixed to 
the bimetallic strip 31 is a U-shaped member which surrounds three sides 
thereof with its legs in facing relation to the trip arm 32 such that, 
when more severe overcurrent flows through the breaker or the bimetallic 
strip 31, it is magnetized thereby to attract the trip arm 32, unlatching 
the cradle 24 in the like manner into the tripped position for separation 
of the contacts, at which occurrence the manual handle 21 is moved to the 
intermediate position between the ON indicating position and OFF 
indicating position, as shown in FIG. 4. Reset of the cradle 24 is made 
simply by pivoting the handle 21 to its clockwise-most or OFF position, 
during which operation a reset lever projecting downwardly from the handle 
21 pushes a pin 26 on the intermediate portion of the cradle 24 to thereby 
move the cradle 24 in the counterclockwise direction as the handle 21 
rotates to move the movable contact arm 22 into the off condition, 
allowing the latch end 25 to slide upwardly along the trip arm 32 for 
latching engagement with the latch hole 36 thereof. In this manner the 
cradle 24 or the manually operable switching mechanism 20 is restored to 
its OFF condition, as shown in FIG. 3. 
Said contact carrier 15 on which the second contact 12 is fixed is 
operatively connected to the remotely controllable switching mechanism 40 
so as to be driven thereby to move between an operative position where it 
is engageable with the first contact 11 and an inoperative or disable 
position where it is no longer engageable with the first contact 11 
independently of the condition of the manually switching mechanism 20. The 
remotely controllable switching mechanism 40 is activated in response to 
the remote control signal and is in the form of a polarized electromagnet 
41 to be energized by such remote control signal. In the present 
embodiment, the electromagnet 41 is of monostable type and comprises, as 
best shown in FIG. 2, a winding 42 wound around a bobbin 43, an armature 
44 extending axially through the bobbin 43, a yoke 45 mounted on one side 
of the bobbin 43 with flanges 46 and 47 at its both ends extending axially 
outwardly from the axial ends of the bobbin 43, the flange 46 at the upper 
end of the bobbin 43 defining a first pole end to which the one end of the 
armature 44 is pivotally supported and the other flange 47 at the lower 
end of the bobbin 43 defining a second pole end which is spaced laterally 
from a pole piece 48 projecting on the lower end of the bobbin 43. A 
permanent magnet 49 is disposed between the second pole end 47 and the 
pole piece 48 for magnetizing them in opposite polarity and at the same 
time interconnecting them in such a manner as to leave therebetween a gap 
into which the other end or the free end of the armature 44 extends. It is 
this armature 44 that is connected at its free end to the contact carrier 
15 of the second contact 12 for movement thereof between the operative 
position and inoperative position in response to energization and 
deenergization of the electromagnet 41. The armature 44 is stable at the 
position indicated by FIG. 1 where it has its free end attracted by the 
effect of the permanent magnet 49 to the pole piece 48 so as to complete 
the magnetic circuit of the magnetic flux emanating from permanent magnet 
49 through the pole piece 48, armature 44, first pole end 47, yoke 45, 
second pole end 47 and returning to permanent magnet 49. In the absence of 
the remote control signal, the armature 44 is retained at this stable 
position by the permanent magnet 49, permitting the contacts to be 
selectively closed and opened by the operation of said manually operable 
switching mechanism 20. When the electromagnet 41 is energized responsive 
to the control signal of a given polarity, the free end of the armature 44 
becomes magnetized in the same polarity as the pole piece 48 but in the 
opposite polarity to the second pole end 47 to be thereby attracted 
thereto, thus moving the second contact 12 away from the first contact 11 
into its inoperative position, as shown in FIG. 5. At this occurrence, a 
stopper projection 8 integral with said partition rib 3 is in abutting 
engagement with the movable contact arm 22 to prevent it from further 
rotating in the clockwise direction, thereby keeping the contact separated 
against the bias of the spring 23. The armature 44 is retained at this 
position while the electromagnet 41 continues to be energized and upon 
deenergization of the electromagnet 41 it returns to its stable position 
due to the magnetic force of the permanent magnet 49, allowing the second 
contact 12 to resume the operative position. 
An indicator lamp 50, which is viewed through a window 9 in the upper wall 
of the breaker housing 1, is inserted in series circuit with the 
electromagnet 41 so as to be turned on when the latter is energized for 
providing a visual indication that the second contact 12 is forcibly 
separated away from the first contact 11 in response to the remote control 
signal. This is advantageous in that the user can easily acknowledge the 
remote control signal responsive operation of separating the contacts and 
is prevented from being confused so as to uselessly manipulate the handle 
13 in an attempt to restore a selective load connected to the breaker. 
Mounted in the bottom of the breaker housing 1 is an arc chute 60 which is 
composed of a stack of U-shaped metal plates 61 slotted to form a passage 
62 through which the first contact 11 moves from its closed position to 
open position. When an arc is drawn between the contacts 11 and 12 upon 
separation thereof particularly due to short-circuit current conditions, 
it will produce in the area between the limbs of each metal plate 61 
magnetic flux which in turn drives the arc downwardly into the bottom of 
the arc chute 60, stretching the arc for rapid extinction thereof. 
It is noted at this time that said contact carrier 15 is formed at its end 
with an elongated conductor plate 52 which has on the intermediate portion 
thereof said second contact 12 and extends in generally parallel relation 
with the movable contact arm 22 in its ON condition. The conductor plate 
52 is electrically connected to the braid 16 at a portion upwardly of the 
second contact 12 so that it flows the current downwardly therethrough 
toward the second contact 12, i.e., in the opposite direction to the 
current flowing upwardly through the movable contact arm 22 from the first 
contact 11 in contact with the second contact 12, with the result of which 
there is developed increased electromagnetic forces interacting between 
the conductor plate 52 and the movable contact arm 22 in such a way as to 
electromagnetically blow them back in opposite directions upon occurrence 
of short circuit current or overload current several times the normal 
rated current flowing through the contacts. Accordingly, the contacts 11 
and 12 can be separated by the above electromagnetic blow back effect even 
before the afore-mentioned trip mechanism 30 is effective to separate the 
contacts, which effect is further enhanced by adopting the above 
arrangement of rendering the contact carrier 15 of the second contact 12 
to be movable independently of the movable contact arm 22 of the first 
contact 11. 
Referring to FIG. 6, a modification of the above embodiment is shown which 
is identical to the above embodiment except that the second contact 12 is 
supported on a contact carrier 54 by means of a compression spring 55. The 
contact carrier 54 having its one end connected to the armature 44 is 
formed at the other end with a bracket 56 to which a conductor plate 57 
having thereon the second contact 12 is slidably connected and is urged by 
the compression spring 55 disposed therebetween in a direction of engaging 
the second contact 12 with the first contact 11 in its ON condition, for 
the purpose of providing a suitable contact pressure between the contacts 
11 and 12. The compression spring 55 also allows the second contact 12 to 
be retarded to a some extent when the second contact 12 is struck by the 
first contact 11 at the time of closing the contacts, thereby serving to 
reduce contact bounce. 
Second embodiment &lt;FIG. 7&gt; 
FIG. 7 shows a second preferred embodiment of the present invention which 
is similar in construction to the above first embodiment except that the 
second contact 12 is operatively connected to the armature 44 of the 
electromagnet 41 through a contact carrier 65 and connecting rod 66. The 
second contact 12 is fixed on the contact carrier 60 having a first pivot 
axis 67 by which it is pivoted to the breaker housing 1 for rotation about 
the first axis 67. The contact carrier 65 also has a second pivot axis 68 
to which is pivoted one end of the connecting rod 66 having the other end 
connected to the armature 44 of the electromagnet 41, so that the contact 
carrier 65 is driven by reciprocating armature 44 to rotate about the 
first pivot axis 67 for movement of the second contact 12 between said 
operative and inoperative positions in response to the deenergization and 
energization of the electromagnet 41. With this contact carrier 65 
pivotally supported to the housing 1, an optimum travel or separation 
distance of the second contact 12 can be obtained with the limited stroke 
of the armature 44 of the electromagnet 41. 
In this embodiment, there is further disclosed a novel and advantageous 
feature of an arc chute 70 which is mounted in the bottom of the breaker 
housing 1 at a location spaced laterally from the second contact 12 but 
adjacent the first contact 11 in its fully opened condition and which has 
an added effect to that of the arc chute 60 employed in the first 
embodiment. The arc chute 70 in the present embodiment comprises a stack 
of metal plates 71 arranged vertically in face-to-face relation, the first 
plate of which is in closer relation to the first contact 11 in its fully 
opened condition and the last plate of which extends along the inner 
bottom of the housing 1 past the second contact 12 to define an arc runner 
73, said arc runner 73 terminating at its end portion outwardly of the 
housing 1 to form thereat said line terminal 17 with a complementary clip 
10 to be electrically charged. The metal plates 71 except the arc runner 
73 are U-shaped plates slotted to form a passage 72 for the first contact 
11 as it is moves between the ON and OFF conditions. The arc runner 73 is 
spaced from said contact carrier 65 with a small gap formed therebetween 
at a portion midway of the arc runner 73 but is electrically connected to 
the contact carrier 65 by the braid 16 at a point offset toward the line 
terminal 17 from the portion confronting the contact carrier 65 so as to 
provide a current path from the line terminal 17 to the second contact 12. 
The contact carrier 65 is formed with a conductor plate 69 on which the 
second contact 12 is held and which extends substantially in parallel 
relation to the movable contact arm 22 in its closed position. The 
conductor plate 69 is electrically connected to the braid 16 at a point 
upwardly of the second contact 12 so that, as in the like manner discussed 
with reference to the first embodiment, the current will flow through the 
conductor plate 69 in the opposite direction to the current flowing 
through the movable contact arm 22 so as to produce like electromagnetic 
force which, in addition to promoting the contact separation upon 
occurrence of short circuit current, drives the arc drawn between the 
contacts 11 and 12 downwardly toward the arc runner 73 in response to such 
short circuit current condition. Whereby the one end of the arc jumps over 
the gap to be transferred from the lower end of the conductor plate 69 to 
the arc runner 73 and proceeds therealong toward the stacks of the metal 
plates 71 as the first contact 11 moves to its fully open position, during 
which process the arc is drawn deeply into the slot of each U-shaped metal 
plate 71 for rapid extinction of the arc. With this arrangement, the arc 
can be immediately transferred from the second contact 12 to the arc 
runner 73 to effectively avoid pitting of that contact, in addition to 
being elongated or stretched for facilitating the extinction of the arc. 
Arcing gases will flow outwardly of the breaker through a vent 74 formed 
at the lower side of the breaker housing 1 adjacent the arc chute 70. 
Third embodiment &lt;FIGS. 8 to 11&gt; 
Referring to FIG. 8, there is shown a third preferred embodiment of the 
present invention which is similar in construction to the first and second 
embodiments except for the construction of the remotely controllable 
switching mechanism 40. The manually operable switching mechanism 20 is 
identical to the first embodiment and therefore is not described in detail 
so as to avoid duplication of the explanation, while like numerals are 
employed to designate like parts in the drawings. The remotely 
controllable switching mechanism 40 is in the form of a polarized 
electromagnet 81 of monostable operation which, as best shown in FIG. 10, 
comprises a winding 82 wound around a bobbin 83, an axially movable 
armature 84 extending axially through the bobbin 83 and connected at its 
one end to a contact carrier 100 of the second contact 12, first and 
second yokes 86 and 87 mounted against the opposite sides of the winding 
82, and a pair of permanent magnets 88 interposed between the yokes 86 and 
87 for magnetizing the same in the opposite polarity. The first and second 
yokes 86 and 87, each being of U-shaped configuration with a pair of 
parallel legs connected by a bight or center portion, are assembled into 
the electromagnet 81 in such a way that the legs of the first yoke 86 
extends over the longitudinal ends of armature 84 at positions axially 
outwardly of the axial ends thereof to define respective outer pole 
members 90 and the legs of the second yoke 87 extends over the ends of the 
winding 82 at positions axially inwardly of the adjacent outer pole 
members 90 to define respective inner pole members 91. The inner pole 
members 91 are each cooperative with the adjacent outer pole members 90 to 
form therebetween air gaps within each of which a pole plate 92 at either 
end of the armature 84 is received so that the armature 84 is axially 
movable upon energization and deenergization of the electromagnet 81 
between two positions at each of which the one of the pole plates 92 is in 
abutting engagement with the adjacent outer pole member 90. Formed 
integrally on either end of the bobbin 83 is a channel member 93 which 
receives on the top of its sidewalls each of the legs or outer pole 
members 90 of the first yoke 86 to retain it in position and receives on 
its bottom wall each of said legs or inner pole members 91 of the second 
yoke 87 to retain it in position. 
Said permanent magnets 88 are interposed between the center portions of the 
first and second yokes 86 and 87 to be secured thereto. Thus, the first 
and second yokes 86 and 87 are spaced in a direction perpendicular to the 
axis of the armature 84 by a maximum distance within the width dimension 
of the electromagnet 81. In other words, the adjacent pairs of inner and 
outer pole members 90 and 91 can be axially aligned at a vertical distance 
much shorter than the lateral distance between the first and second yokes 
86 and 87, so that the permanent magnets 88 can have their flux 
concentrated to act over each of the vertical gaps between the outer pole 
member 90 and the inner pole member 91 without causing substantial leakage 
thereof acting laterally between the center portions of the first and 
second yokes 86 and 87. Consequently, the electromagnet 81 of the above 
construction can be efficiently operated at a lesser power requirement by 
elimination of ineffective flux leakage of the permanent magnets 88 and at 
the same time being made compact in size. 
One of the inner pole members 91 is dimensioned to be considerably shorter 
than the other so that the shorter inner pole member 91 is not effective 
for attracting the adjacent pole plate 92 of the armature 84 to retain the 
armature 84 in position upon deenergization of the electromagnet 81, 
whereby the electromagnet 81 is rendered to have monostable operation 
which allows the armature 84 to be stable only at the position of FIG. 8, 
where the armature 83 has its upper pole plate 92 in abutting engagement 
with the adjacent outer pole member 90 and at the same time has its lower 
pole plate 92 in proximity to the adjacent inner pole member 91 of longer 
dimension for completing the magnetic circuit of the magnetic flux of the 
permanent magnets 88. Projecting downwardly from the lower end of the 
armature 84 is a stud 94 which is connected through a connecting rod 95 to 
said contact carrier 100 so as to retain the second contact 12 on the 
contact carrier 100 in the operative position, as shown in FIG. 8, 
allowing the contact closing and opening when the armature 84 is in the 
stable position or under a deenergized condition. When the electromagnet 
81 is energized by a remote control signal of a given polarity, the 
armature 84 is driven to move axially downwardly so as to actuate the 
second contact 12 into the inoperative position, as shown in FIG. 11, 
where the second contact 12 is moved away from the first contact 11 to 
disable the contact closing independently of the position of the first 
contact 11. The above inoperative position is the unstable position so 
that upon deenergization of the electromagnet 81 the second contact 12 
returns to the operative position of FIG. 8. 
As in the like manner in the second embodiment of FIG. 7, the contact 
carrier 100 of the second contact 12 is pivotally supported at a first 
pivot axis 101 to the breaker housing 1 and is pivotally connected at a 
second pivot axis 102 to the connecting rod 95 leading to the armature 84 
so that contact carrier 100 is driven to rotate about first pivot axis 101 
for moving the second contact 12 between the operative and inoperative 
positions upon deenergization and energization of the electromagnet 81. In 
this embodiment, the contact carrier 100 is further provided with a 
slidable contact plate 103 on which the second contact 12 is fixed and 
which is connected to contact carrier 100 through the like compression 
spring 104 as in the modification of the first embodiment, which spring 
104 being introduced for the same purposes of the above modification and 
seated in the recess of contact carrier 100. 
In addition, the present embodiment also includes like arc chute 70 of the 
same construction and operational feature as in the second embodiment. 
FIGS. 12 and 13 show a modification of the above third embodiment which is 
identical to the third embodiment except that the electromagnet 81' is 
designed to have the armature 84 stable only when retaining the second 
contact 12 in its inoperative position, which is in direct contrast to the 
electromagnet 81 of the third embodiment where the armature 84 is stable 
when retaining the second contact 12 at its operative position. To this 
end, one of the inner pole members 91 at the lower end of the winding 82 
is made shorter than the other inner pole member 92 such that the lower 
pole plate 92 of the armature 84 will not be kept attracted upwardly to 
the adjacent shorter inner pole member 91 after the deenergization of the 
electromagnet 81' and instead it is attracted to the adjacent outer pole 
plate 90 for retaining the second contact 12 at its inoperative position, 
as shown in FIG. 13. This lasts until the electromagnet 81' is again 
energized to move the armature 84 axially upwardly for bringing the second 
contact 12 into the operative position, as shown in FIG. 12. 
Fourth embodiment &lt;FIGS. 14 to 19&gt; 
Referring to FIG. 14, there is shown a fourth embodiment of the present 
invention. The circuit breaker of the present embodiment comprises a 
combination of manually operable switching mechanism 120 and trip 
mechanism 130 of different types from those of the previous embodiments 
and includes a polarized electromagnet 141 of bistable operation as the 
remotely controllable switching mechanism 140. The manually operable 
switching mechanism 120 is responsible for closing and opening a single 
set of first and second contacts 111 and 112 in delayed-make and 
quick-break fashion and comprises a manual handle 121 operatively 
connected to a movable contact arm 122 carrying the first contact 111 
through a linkage 123. 
Included in said trip mechanism 130 is a trip arm 132 pivoted at its center 
to a breaker housing 110 and is urged by a torsion spring 133 in a 
clockwise direction as viewed in the figures and a bimetallic strip 131 
which is mechanically and electrically connected at its end to a line 
terminal 114 and is electrically connected to a movable contact arm 122 
carrying the first contact 111 by a flexible braid 113. The manual handle 
121 is pivoted at a handle pivot 116 to the breaker housing 110 and is 
urged by a torsion spring 124 in the clockwise direction, or into an OFF 
position. Said linkage 123 comprises a link 125 with one end pivoted to 
the manual handle 121 and with the other end pivoted to one end of a 
leaper plate 126 which is engageable at its other end with a latch 
projection 134 at the lower end of the trip arm 132. The leaper plate 126 
extends through the upper portion of a joint member 127 of insulative 
material and is fulcrumed at its intermediate portion against the joint 
member 127, said leaper plate 126 having at the other end adjacent the 
trip arm 122 a latch end 128 engageable with the latch projection 134. The 
joint member 127, which is vertically movable between a pair of parallel 
ribs 117 on the inner wall of the breaker housing 110, has its lower end 
in abutting engagement with the end of the movable contact arm 122 remote 
from its pivoted end and is biased upwardly together with the movable 
contact arm 122 by a torsion spring 129 acting upon the movable contact 
arm 122. 
In operation, when the manual handle 121 is moved to its 
counterclockwise-most position or ON position, as shown in FIG. 14, said 
linkage 123 acts to gradually push down the movable contact arm 122 
against the bias of the torsion spring 129 for bringing the first contact 
111 into contacting engagement with the second contact 112 in delayed-make 
fashion, by keeping the latch end 128 of the leaper plate 126 engaged with 
the latch projection 134, at which condition the link 125 applies its line 
of action to the manual handle 121 for continuously urging the manual 
handle 121 against the wall of the breaker housing 110 in the 
counterclockwise direction, thus retaining the manual handle 121 at its ON 
position. When on the other hand, the manual handle 121 is manipulated to 
its clockwise-most position or OFF position, as shown in FIG. 17, the link 
125 no more applies downward force to the one end of the leaper plate 126, 
which responds by moving upwardly due to the bias of the spring 129 with 
its latch end 128 kept engaged with the latch projection 134 of the trip 
arm 122, thus allowing the joint member 127 and the movable contact arm 
122 to move upwardly for separation of the contacts, at this condition the 
manual handle 121 receives the line of action of the link 125 to be 
thereby urged in the clockwise direction against the wall of the housing 
110 so as to be retained at this position. 
In the event of overload currents flowing through the breaker, the 
bimetallic strip 131 is resistively heated to deflect its upper end so as 
to drive the trip arm 132 in the counterclockwise direction to thereby 
unlatch the leaper plate 126, at which moment, the leaper plate 126 
responds to jump upwardly together with the joint member 127 and the 
movable contact arm 122 for rapid separation of the contacts 111 and 112, 
as shown in FIG. 18. After the trip mechanism 130 acts to release the 
contacts, the spring 129 no longer applies its urging force to the manual 
handle 121 at the condition of FIG. 18, whereby the handle 121 is allowed 
to move back to its clockwise-most position or OFF position by the bias of 
the spring 124 lifting up the pivot end of the leaper plate 126 to rotate 
it in the clockwise direction until the latch end 128 is again engaged 
with the latch projection 134 of the trip arm 132. In this manner, the 
movable switching mechanism 120 is returned to the OFF position of FIG. 
17. 
Said polarized electromagnet 141 employed as the remotely controllable 
switching mechanism 140 is of bistable construction and thus the second 
contact 112 is operatively connected to the electromagnet 141 to be 
rendered stable both at its operative and inoperative positions. The 
electromagnet 141 is identical in construction to that of the previously 
described third embodiment except that the inner pole members 91 of the 
second yoke 87 are designed to have the same dimensions, and therefore 
like numerals are employed to designate like parts. With the arrangement 
of incorporating the identical inner pole members 91 in the electromagnet 
141 of the present embodiment, the armature 84 is movable between two 
stable positions at each of which the armature 84 has its upper and lower 
pole plates 92 attracted to the adjacent outer pole member 90 and the 
inner pole member 91 to complete the magnetic circuit of the permanent 
magnet flux. Thus, the second contact 112 operatively connected to the 
armature 84 can be held at both of the operative and inoperative positions 
without continued energization of the electromagnet 141. Projecting on the 
lower pole plate 92 of the armature 84 is a stud 150 which extends 
downwardly through the outer pole member 90 for connection with one end of 
a contact carrier 151, said contact carrier 151 being pivoted at its 
center to the breaker housing 110 and provided at the other end with said 
second contact 112, said contact carrier 151 being electrically connected 
through a braid 118 to a line terminal 115. A compression spring 152 is 
interposed between the stud 150 and the contact carrier 151 for the 
purpose of providing an optimum contact pressure between the contacts as 
well as shock absorbing action at the time of contact closing, as in the 
previous embodiment of FIG. 8. 
Projecting on the upper pole plate 92 of the armature 84 is a plunger 153 
which extends through the outer pole member 90 to be engaged with an 
indicator 155 for actuation thereof. As best shown in FIG. 15, the 
indicator 155 has two angularly displaced segments 156 and 157, one marked 
with "ON" indication and the other with "OFF" indication. The indicator 
155 is pivotally supported on a horizontal axis 158 to be rotatable 
thereabout and is urged by a torsion spring 159 in one direction, i.e, the 
clockwise direction as viewed in the figures. Said plunger 153 is in such 
a relation with the indicator 155 that when the armature 84 moves upwardly 
to bring the second contact 112 into its inoperative position, the plunger 
153 pushes the indicator 155 against the bias of the spring 159 to rotate 
the same into a position where the "OFF" indication on the indicator 155 
can be viewed through a window 119 in the upper wall of the breaker 
housing 10, as shown in FIG. 19, by which indication the user near the 
breaker can acknowledge that the breaker is under remote operation 
responsive to the control signal for moving the second contact 112 into 
its inoperative position or condition of disabling the contact closing. 
When the armature 84 is driven to move downwardly together with the 
plunger 153 for moving the second contact 112 into its operative position 
capable of bringing the second contact 112 into and out of contacting 
engagement with the first contact 111, as shown in FIGS. 14, 17, and 18, 
the indicator 155 rotates correspondingly in the opposite direction under 
the influence of the spring 159 into the position where the "ON" 
indication can be viewed through the window 119 for visual indication of 
such condition. It is to be noted at this point that when the second 
contact 112 is actuated by the electromagnet 141 to move into the 
inoperative position, the movable contact arm 122 carrying the first 
contact 11 is blocked by the spring 129 from moving towards the second 
contact 112 so as to be kept apart from the second contact 112 by a 
suitable distance.