Circuit breaker, and accessory switches thereof

Details Circuit breaker, and accessory switches thereof Circuit breaker, and accessory switches thereof

2001-08-30

2003-05-06

Donovan, Lincoln (Department: 2832)

Electricity: magnetically operated switches, magnets, and electr

Electromagnetically actuated switches

Multiple contact type

C335S172000

Reexamination Certificate

active

06559745

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Technical Field
The present invention is intended for a molded case circuit breaker for protecting a low-tension power distribution facility, such as an electric motor, from an overcurrent. The present invention relates to interior accessories (e.g., optional components), such as an ancillary switch for detecting the ON/OFF status of a primary circuit contact point and a tripping action, a circuit breaker equipped with an alarm switch, and their accessory switches.
2. Related Art
As shown in
FIG. 7
, reference numeral
1
designates a case (plastic mold case) of a circuit breaker. The case
1
houses a breaking section
2
of a main circuit, a toggle-link-type open-close mechanism section
3
, and a tripping section
4
. The open-close mechanism section
3
is coupled to an assembly (not shown) of a movable contact of the breaking section
2
in combination with an open-close lever
6
. The open-close lever
6
is pivotally actuated by means of actuation of the open-close mechanism section
3
, thus switching the contact of the main circuit. When a handle
5
is manually moved to an ON/OFF position, a toggle link mechanism of the open-close mechanism section
3
is actuated, thereby opening or closing the contact of the main circuit of the breaking section
3
. As is well known, in the event of inflow of an overcurrent to the main circuit, the open-close mechanism section
3
causes tripping section in accordance with a signal output from the tripping section
4
, thus opening the contact of the main circuit.
Accessory switch housing sections
1
a
and
1
b
are provided side-by-side on the upper surface of the case
1
. An ancillary switch
7
and an alarm switch
9
, which are of cassette type, are to be connected to the respective accessory switch housing sections
1
a
and
1
b.
In addition to the pivotal open-close lever
6
which opens and closes the contact of the main circuit of the breaking section
2
, the open-close mechanism
3
of the breaker main unit is provided with an alarm output plate
8
which is slid in conjunction with tripping operation of the breaker. Two pairs of output protrusion
6
a
and output plate
8
a
are provided such that one pair protrudes so as to oppose one of the accessory switch housing sections
1
a
and
1
b
and such that the other pair protrudes so as to oppose the remaining accessory switch housing section. The output protrusion
6
a
of the open-close lever
6
and the output protrusion
8
a
of the alarm output plate
8
are provided side-by-side so as not to cause interference therebetween.
FIGS. 8A through 8C
show the buildup structure of the open-close mechanism section
3
. The open-close lever
6
pivots around a spindle
6
b
by means of operation of the open-close mechanism section
3
. In synchronism with pivotal movement of the open-close lever
6
, a pair projection which consist of the left-side and right-side output projections
6
a
and project from a frame of the open-close mechanism section move vertically. The alarm output plate
8
effects guiding and supporting action in a vertically movable manner along the frame of the open-close mechanism section
3
. In a steady state, the alarm output plate
8
is retained and locked in an illustrated lower position. A latch is disengaged from a latch receiver
3
a
of the open-close mechanism section
3
in accordance with an output from the tripping section
4
(see FIG.
7
), thereby causing tripping operation. As a result, a toggle shaft
3
b
of the open-close mechanism section causes pivotal movement, thus releasing the alarm output plate
8
from a locked state. The alarm output plate
8
is susceptible to spring force of a constriction spring
8
b
, thereby causing upward sliding action. As a result, the output projections
8
a
formed on both legs of the alarm output plate
8
are moved upwardly.
The ancillary switch
7
and the alarm switch
9
provided in the accessory switch housing sections
1
a
and
1
b
are constructed such that operation levers coupled to movable contacts project from the front surface of a unit case having a contact mechanism incorporated therein. In a state in which the ancillary switch
7
and the alarm switch
9
are provided in the breaker case
1
(see FIGS.
7
A and
7
B), an operation lever projecting from the ancillary switch
7
opposes the output protrusion
7
a
of the open-close lever
6
, and an operation lever projecting from the alarm switch
9
opposes the output protrusion
8
a
of the alarm output plate
8
. When the circuit breaker is turned ON/Off or tripped, a mechanical signal is transmitted to the ancillary switch
7
by way of the output protrusion
6
a
of the open-close lever
6
, and a mechanical signal is transmitted to the alarm switch
9
by way of the alarm output plate
8
. As a result, the switches are actuated in accordance with the signals, thus outputting electric signals to the outside of the circuit breaker.
The illustrated example shows a case where the alarm switch
9
and the ancillary switch
7
are provided in the accessory switch housing sections
1
a
and
1
b
of the case
1
. There may also be possible to use the circuit breaker by means of providing the ancillary switch
7
into the accessory switch housing sections
1
a
and
1
b
without use of the alarm switch
9
.
Problems to be Solved
The output signal transmission mechanism of related-art structure has the following problems:
(1) The pair of output protrusions
6
a
are formed in non-symmetrical positions on the open-close lever
6
so as to match the positions of operation levers of the ancillary switches
7
provided in the accessory switch housing sections
1
a
and
1
b
. For this reason, as shown in
FIG. 8B
, the output protrusion
6
a
assumes a complicated stepped geometry.
(2) The alarm output plate
8
is provided along the exterior of the frame of the open-close mechanism section
3
and effects guiding and supporting action in a vertically slidable manner without involvement of occurrence of interference with the open-close lever
6
. By means of the a toggle shaft and a drive spring of the open-close mechanism which causes pivotal movement at the time of tripping operation, the alarm output plate
8
is actuated. Therefore, the alarm output plate
8
assumes a complicated geometry and a complicated guide mechanism. Hence, the number of parts constituting the alarm output plate
8
, the number of processes for assembling the alarm output plate
8
, and the space occupied by the alarm output plate
8
become large. In terms of operation, friction or abrasion of components of the guide mechanism stemming from sliding action is apt to cause resistance or rattle, thus posing difficulty in ensuring smooth operation over a long period of time.
SUMMARY OF THE INVENTION
The present invention has been conceived in light of the foregoing drawback and is aimed at solving the foregoing drawback and at providing an improved circuit breaker capable of accurately transmitting a mechanical signal output from a breaker main unit to an ancillary switch and an alarm switch provided in accessory switch housing sections of a breaker case, with use of a simple mechanism and stable operation.
Means for Solving the Problems
To achieve the object, the present invention provides a circuit breaker including:
a breaker case;
left-side and right-side accessory switch housing sections for housing accessory switches of cassette type; that is, an ancillary switch for detecting an ON/OFF state of a contact of a main circuit by means of an electric signal and an alarm switch for detecting tripping operation by means of an electric signal; the ancillary switch being opened/closed in conjunction with an output protrusion formed on an open-close lever of an open-close mechanism for opening/closing a contact of a main circuit; and
the alarm switch being opened/closed in conjunction with an alarm output plate which operates in accordance with tripping action of the open-close mechanism, wherein
a symmetrically bifurcated output p

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