Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Automatic circuit-interrupting devices
Reexamination Certificate
2000-08-03
2001-05-08
Barrera, Ramon M. (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Automatic circuit-interrupting devices
C335S021000, C335S167000
Reexamination Certificate
active
06229414
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a circuit breaker which is used to make and break a low voltage circuit or protect such low voltage circuit and, in particular, to a make-and-break mechanism for making and breaking the contact of a movable contact member.
2. Description of the Related Art
Conventionally, as a make-and-break mechanism of the above type for use in a circuit breaker, there is known a make-and-break mechanism which comprises: an operation handle rotatably supported on a frame composed of a cover plate and a back plate through a handle shaft; a make-and-break lever rotatably supported on a case through a make-and-break shaft and energized in one direction by a main spring; a mechanism member for transmitting the operation of the operation handle to the make-and-break lever; a latch having one end connected to the operation handle through the above handle shaft; a U-shaped pin disposed so as to bridge over the latch and mechanism member; and, a latch receiver rotatably supported on the above frame through a fulcrum shaft and, in the on state of the make-and-break mechanism, capable of securing the other end of the latch, wherein, in case where the secured condition of the latch by the latch receiver is removed due to the operation of an overcurrent detect portion of the make-and-break mechanism (a trip operation), the make-and-break lever is driven to an off position due to the stored energy of the main spring to thereby break the contact of a movable contact member, and, during this operation, that is, during the trip operation, an alarm output plate, which is disposed in the make-and-break mechanism so as to slide along the cover plate, is moved upwardly from a wait position to thereby operate an alarm contact.
Now,
FIG. 7
is a front view of a conventional make-and-break mechanism including the above-mentioned alarm output plate, showing the on state thereof. In
FIG. 7
, although the alarm output plate
56
is energized upwardly by an output plate spring
70
consisting of a tension spring interposed between the alarm output plate
56
and a cover plate
27
consisting of the support frame of the make-and-break mechanism, the engaging portion
56
a
of the alarm output plate
56
is secured by a latch receiver
47
for securing a latch
34
, whereby the alarm output plate
56
is held at a wait position shown in FIG.
7
. The latch receiver
47
is rotatably supported on the support frame of the make-and-break mechanism through a projecting shaft
47
a
formed integral with the latch receiver
47
in the right and left direction and is energized clockwise by a return spring
50
which is inserted between the latch receiver
47
and cover plate
27
.
Also, in
FIG. 7
, between the cover plate
27
and a pin
39
which connects an operation handle
26
to the mechanism member
36
of the make-and-break mechanism, there is provided a handle spring
59
which consists of a tension spring, while the operation handle
26
is energized clockwise. Further, an accessory linking plate
71
is guided to and held by the cover plate
27
in such a manner that it can be slided in the right and left direction, while the leading end of the accessory connecting plate
71
is opposed to the latch receiver
47
. Between the accessory linking plate
71
and cover plate
27
, there is provided a return spring
72
consisting of a tension spring.
The structure and operation of the make-and-break mechanism shown in
FIG. 7
are substantially the same as those of the present invention which will be described hereinafter, and thus the detailed structure and operation thereof will be given through the detailed description of a mode for carrying out the present invention. That is, here, description will be given below of the trip operation of the make-and-break mechanism shown in FIG.
7
. In the on state shown in
FIG. 7
, in case where an overcurrent flows in a circuit breaker, an overcurrent detect portion (not shown) is operated to push the upper end of the latch receiver
47
in the left direction, thereby rotating the projecting shaft
47
a
thereof counterclockwise. This removes the secured condition of the latch
34
by the latch receiver
47
. As a result of this, a make-and-break lever
25
rotatably supported on the case through a make-and-break shaft
24
is driven or rotated due to the energy that is stored in a main spring
64
, which breaks the contact of a movable contact member (not shown) (that is, trip operation). At the same time, the operation handle
26
rotatably supported by a handle shaft
31
is driven or rotated clockwise by the spring force of the handle spring
59
, so that the operation line of the handle spring
59
stops at a position passing through the center of the handle shaft
31
. This position is a trip display position and, at this position, the operation handle
26
is held in the horizontal attitude. This horizontal attitude of the operation handle
26
shows the generation of the trip operation.
Also, due to the above-mentioned rotation of the latch receiver
47
, the secured position of the alarm output plate
56
is also removed at the same time and thus the alarm output plate
56
is moved upwardly by the spring force of the output plate spring
70
. As a result of this, an alarm contact (not shown), which is disposed so as to be operated in linking with the alarm output plate
56
, is operated, so that a trip signal is issued to the outside. On the other hand, in case where the accessory linking plate
71
, which is used to operate or turn off the circuit breaker remotely by a voltage trip device, is pushed in the right direction against the return spring
72
by the voltage trip device (not shown), the latch receiver
47
is driven or rotated counterclockwise, which, similarly to the above-mentioned case, breaks the contact of the movable contact member.
In the above-mentioned make-and-break mechanism, conventionally, the alarm output plate
56
is normally secured by the latch receiver
47
and, at the same time, in the trip operation, the alarm output plate
56
is moved from the wait position by the output plate spring
70
. Because of this, to the latch receiver
47
, there are applied a load from the latch
34
as well as a load from the alarm output plate
56
, which, in the trip operation, requires a large load force to drive or rotate the latch receiver
47
. This leads to the increased size of the overcurrent detect portion as well as makes it easy to cause variations in the tripping characteristic. Also, the alarm output plate
56
requires an exclusive member, that is, the output plate spring
70
; and, further, there are necessary another exclusive members which are used when an off operation is carried out by the voltage trip device, that is, the accessory linking plate
71
and its return spring
72
. That is, the conventional make-and-break mechanism requires a large number of parts.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the drawbacks found in the conventional make-and-break mechanism. Accordingly, it is an object of the invention to provide a make-and-break mechanism for use in a circuit breaker which not only can relieve the load of a latch receiver but also can reduce the number of parts necessary around an alarm output plate to thereby simplify the structure of the make-and-break mechanism.
In attaining the above object, according to the invention, there is provided a make-and-break mechanism for use in a circuit breaker in which the alarm output plate is secured to the frame of the make-and-break mechanism and, in the trip operation of the make-and-break mechanism, the secured condition of the alarm output plate is removed using the stored energy of the main spring, whereby the load to be applied to the latch. receiver can be relieved and, at the same time, the alarm output plate is moved using the handle spring used to the operation handle to the trip display position to thereby omit the output plate spring that is conventionally used.
T
Asakawa Koji
Fujihira Takumi
Kawata Hisao
Kuboyama Katsunori
Nomura Koji
Barrera Ramon M.
Fuji Electric & Co., Ltd.
Pearne & Gordon LLP
LandOfFree
Make-and-break 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 Make-and-break mechanism for circuit breaker, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Make-and-break mechanism for circuit breaker will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2521067