Electricity: circuit makers and breakers – Special application – Actuated concurrently with operation or use of art device
Reexamination Certificate
2001-10-22
2003-09-16
Enad, Elvin (Department: 2832)
Electricity: circuit makers and breakers
Special application
Actuated concurrently with operation or use of art device
C200S400000, C200S050020, C200S318000, C200S321000
Reexamination Certificate
active
06621020
ABSTRACT:
BACKGROUND OF THE INVENTION AND ART STATEMENT
The present invention relates to a breaking mechanism for a circuit breaker, such as a molded-case circuit breaker or an earth-leakage circuit breaker, and in particular, to the shapes of engaging surfaces between a latch for locking a toggle link when a movable contact shoe is closed and a latch receiver for engaging and locking the latch.
A breaking mechanism for a circuit breaker as mentioned above generally comprises a latch supported rotationally movably, and a latch receiver supported rotationally movably and generally engaging and locking the latch to prevent the rotational movement thereof. The latch locks a toggle link to keep an interrupting spring in a force-stored state when a movable contact shoe is closed, and the latch is released from the engagement and then rotationally moved to unlock the toggle link to open the movable contact shoe using the force stored in the interrupting spring when the current flowing through the circuit breaker becomes excessive to operate a tripping device to thereby rotationally move the latch receiver.
FIG. 4
is a side view showing an example of a breaking mechanism of this type.
FIG. 5
is a sectional view taken along line
5
—
5
in FIG.
4
. In
FIG. 5
, the electric path for each phase in a circuit breaker comprises a current-interrupting section composed of a pair of fixed contact shoes
1
and
2
arranged in a longitudinal direction, and a movable contact shoe
3
bridging across the fixed contact shoes
1
and
2
. The movable contact shoe
3
is held by a movable-contact-shoe holder
4
that is composed of an insulator, is provided for each pole, and is pressed against the fixed contact shoes
1
and
2
by a contact spring
5
composed of a compressed coil spring inserted between the movable contact shoe
3
and a case (not shown). The movable contact shoe
3
interrupts a current by being pressed down by an interrupting lever
7
and separated from the fixed contact shoes
1
and
2
, as indicated by the line with alternating one long and two short dashes. The interrupting lever
7
is rotationally driven clockwise as shown in
FIG. 5
by the force stored in an interrupting spring
6
composed of a torsion spring. When the movable contact shoe
3
is closed as shown in the figure, the interrupting lever
7
is held at the position indicated by the solid line in the figure to keep the interrupting spring
6
in a force-stored state.
In
FIGS. 4 and 5
, the illustrated breaking mechanism is formed as a unit, and the parts thereof are supported by a frame
8
having right and left side plates
8
a
(FIG.
5
). In
FIG. 4
, the side plate
8
a
closest to the reader is omitted. The frame
8
has a butterfly-shaped operating handle
9
rotatably movably supported via a handle shaft
10
, and the handle shaft
10
has a latch
11
connected thereto to be freely rotationally supported thereat. The latch
11
is separated except for an L-shaped bent portion
11
a
located at a tip thereof, and has right and left side plates so as to sandwich the operating handle
9
.
The operating handle
9
is connected to an upper end of an upper link
12
via a connection shaft
13
. The upper link
12
is connected at a lower end thereof to an upper end of a lower link
14
via one end of a U-shaped pin
15
. The upper link
12
and the lower link
14
have right and left side plates, respectively. The upper link
12
sandwiches the operating handle from both sides thereof, whereas the lower link
14
sandwiches the upper link
12
from both sides thereof. The U-shaped pin
15
has its other end engaging the latch
11
to bind the upper link
12
and the lower link
14
against the latch
11
. The upper link
12
and the lower link
14
constitute a toggle link.
The lower link
14
has a transmission pin
16
installed at a lower end thereof. The transmission pin
16
has both ends inserted and guided into slits
17
formed in the respective frame side plates
8
a.
The interrupting lever
7
has the other transmission pin
18
installed thereon so as to cross the transmission pin
16
. That is, this mechanism includes a pair of interrupting levers
7
each having opposite ends thereof coupled to an opening-and-closing shaft
19
with a space therebetween, which is rotationally movably supported on a case (not shown). The transmission pin
18
is installed so as to extend between the interrupting levers
7
. The opening-and-closing shaft
19
has a pair of interrupting springs
6
fitted on the respective ends thereof, wherein one end engages the transmission pin
18
, and the other end engages the frame
8
, respectively. The interrupting spring
6
, however, has been twisted and is in a force-stored state such that it applies a push-up force P from the transmission pin
18
to the transmission pin
16
as shown in
FIG. 4
, so as to rotationally move the interrupting lever
7
clockwise as shown in FIG.
5
.
The above force P causes the transmission pin
16
of the lower link
14
to move upward along the slit
17
, so that the lower link
14
starts to rotationally move counterclockwise as shown in
FIG. 4
, using the transmission pin
16
as a support point. Since, however, the upper end of the lower link
14
is bound by the U-shaped pin
15
, the lower link
14
can not move, so that it maintains the illustrated position. At the same time, tensile force Q from the lower link
14
acts on the latch
11
via the U-shaped pin
15
. Thus, the latch
11
starts to rotationally move clockwise as shown in
FIG. 4
using the handle shaft
10
as a support point. The latch
11
, however, is engaged and locked by the latch receiver
20
to maintain the illustrated position.
The latch receiver
20
is shaped like a plate extending in a vertical direction and having a pair of arms
20
a
folded in basically the middle thereof and spaced in a lateral direction. The plate portion of the latch receiver
20
has a square window slit near the arms
20
a.
The latch receiver
20
is supported on the frame
8
via a support shaft
21
penetrating the arms
20
a,
so as to move freely rotationally, and is engaged and locked so that an engaging surface at a lower edge of the window slit engages an engaging surface
11
b
of the latch
11
, to thereby prevent the latch
11
from rotationally moving. The latch receiver
20
receives force from the latch
11
and starts to rotationally move clockwise as shown in
FIG. 4. A
laterally projecting tongue
20
c,
however, abuts against a notched edge of the frame side plate
8
a
to prevent the latch receiver
20
from rotationally moving. Thus, the latch receiver
20
is kept in the illustrated standing position. Further, a return spring
22
composed of a compression coil spring is inserted between a lower end of the latch receiver
20
and the frame
8
to urge the latch receiver
20
clockwise as shown in FIG.
4
.
With the breaking mechanism, when the current flowing through the circuit breaker becomes excessive, the latch receiver
20
undergoes a tripping-operation force R from an overcurrent tripping device (not shown) to rotationally move counterclockwise to the position indicated by the broken line, as shown in FIG.
4
. The latch
11
is then disengaged and becomes rotationally movable clockwise. As a result, the toggle links
12
and
14
change into a V shape to rotationally drive the interrupting lever
7
clockwise as shown in
FIG. 5
, using the force stored in the interrupting spring
6
. The interrupting lever
7
pushes the movable contact shoe
3
downward via the movable-contact-shoe holder
4
to open and separate it from the fixed contact shoes
1
and
2
, thereby interrupting the current.
FIG. 6
is an enlarged vertical sectional view showing a conventional engaging portion between the latch
11
and the latch receiver
20
in the breaking mechanism described above. In
FIG. 6
, the latch
11
has an engaging surface
11
b
that engages an engaging surface
20
b
of the latch receiver
20
. The engaging surfaces
11
b
and
20
b
are both fla
Fujiwara Tsuneo
Hamada Yoshinobu
Jumonji Yoshimi
Kaihoku Toshizo
Sekine Nobuhiro
Enad Elvin
Fuji Electric & Co., Ltd.
Kanesaka & Takeuchi
Lee K.
LandOfFree
Breaking mechanism for circuit breaker does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Breaking mechanism for circuit breaker, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Breaking mechanism for circuit breaker will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3109636