Electricity: circuit makers and breakers – Interlocking – Drawout-type switchgear
Reexamination Certificate
2001-11-30
2003-05-06
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Interlocking
Drawout-type switchgear
C200S308000
Reexamination Certificate
active
06559394
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a draw out type air circuit breaker, and in particular to a draw out type air circuit breaker which is capable of distinguishing accurately a disconnected position, a testing position and a connected position when a breaker is pushed in/drew out from a cradle.
2. Description of the Prior Art
Generally, an air circuit breaker is installed between a load equipment and electric power in order to protect the load equipment such as a motor and a converter, etc. and a line from an abnormal current (a short circuit, a ground fault, an over current) generated at an electric circuit such as a power transmission/distribution line and private power transforming facilities, etc. Particularly, an air circuit breaker is a breaker for extinguishing an arc generated in opening and closing of a contact within the air.
An air circuit breaker is divided into a fixed type fixedly installed between an electrical power and an electrical load and a draw out type in which a breaker is movable so as to be separated from a power terminal and a load terminal in order to facilitate maintenance and secure stability.
FIG. 1
is a side view illustrating a state in which a cradle is separated from a breaker body in a general draw out type air circuit breaker being applicable a position indicating apparatus in accordance with the present invention.
The draw out type air circuit breaker includes a cradle
100
having an opened side toward a breaker body
200
and provided with a power source terminal
202
connected to electrical power source and a load terminal
204
connected to an electrical load equipment, a breaker body
200
movable so as to be pushed in/drew out from the cradle
100
and connecting or disconnecting a circuit between the power source and the load, and an interlock apparatus
300
for indicating a present position such as a disconnected position, a testing position, a connected position of the breaker body
200
when the breaker body
200
is pushed in/drew out from the cradle
100
.
Herein, connectors
206
,
208
are respectively connected to the power source terminal
202
and the load terminal
204
of the cradle
100
, the connectors
206
,
208
are respectively connected to a power source terminal
210
and a load terminal
212
projected from the breaker body
200
, accordingly the cradle
100
and the breaker body
200
are mechanically and electrically connected each other.
And, the cradle
100
includes a guide frame
214
for guiding the translocation of the breaker body
200
when the breaker body
200
is pushed in/drew out.
FIG. 2
is a side view illustrating an interlock apparatus of a draw out type air circuit breaker in accordance with the prior art.
The interlock apparatus in accordance with the prior art includes a base frame
102
fixed to the breaker body
200
, a lead screw
104
supported by the base frame
102
so as to be rotatable, a screw pipe
106
fixed to the cradle
100
and inserted by the lead screw
104
, a position indicating apparatus
108
installed on the base frame
102
and for indicating a position of the breaker body
200
when the lead screw
104
is meshed with the screw pipe
106
, and a lock slide
110
connected to the position indicating apparatus and for locking a position when the breaker body
200
is placed at one of the disconnected position, the testing position or the connected position.
The position indicating apparatus
108
includes a lead bar
112
placed so as to be parallel with the lead screw
104
, abutted to one wall surface of the cradle
100
and retreated relatively when the lead screw
104
is meshed with the screw pipe
106
and linearly moves, a cam
114
connected to the lead bar
112
and installed on the base frame
102
so as to be rotatable in order to perform a rotation motion while retreating of the lead bar
112
, and a indicating means
107
connected to one end of the cam
114
and for indicating a position of the breaker body
200
by linearly moving in accordance with the rotation of the cam
114
.
In the lead bar
112
, a lead bar
112
is a rod shaped member having a predetermined length and portion of the lead bar
112
is installed at the side of the lead screw
104
so as to be parallel with the lead screw
104
, the other portion of is the lead bar
112
is curved so as to be inserted into a slot
118
formed at the cam
114
.
And, a breakaway preventing member
120
for preventing a breakaway of the lead bar
112
from the slot
118
is installed on the end of the lead bar
112
inserted into the slot
118
.
A return spring
122
for providing an elastic force in order to return the lead bar
112
to an its original position after operation is installed between the breakaway preventing member
120
and the base frame
102
.
The cam
114
has a hinge portion
126
so as to be rotatively installed to the base frame
102
, a slot
118
in which the lead bar
12
is inserted is provided at the lower portion of the hinge portion
126
so as to be curved a certain times at a predetermined angle, and a connection pin
124
connected to an indicating plate
150
placed at the front of the hinge portion
126
.
As depicted in
FIG. 3
, the indicating means
107
includes an indicating plate
150
placed at the rear of the base frame
102
so as to be linearly movable up and down, a front plate
152
placed at the front of the indicating plate
150
, and a guide plate
154
placed a the rear of the indicating plate
150
, fixed to the base frame
102
and for guiding the up and down movement of the indicating plate
150
.
The indicating plate
150
is a flat plate and is provided with a color indicating portion
156
on the its upper front surface in order to indicate a position of the breaker body
200
with colors, and a connection pin
124
of the cam
114
is connected to one side surface of the indicating plate
150
.
The front plate
152
is placed at the front of the indicating plate
150
, fixed to the base frame
102
and has three display windows
158
,
160
,
162
for indicating a position of the color indicating portion
156
of the indicating plate
150
, and a handle insertion hole
164
is formed at the center of the front plate
152
in order to insert a handle (not shown) for rotating the lead screw
104
.
In the indicating means
107
, when the indicating plate
150
connected to the cam
114
by the connection pin
124
moves up and down according to the rotation of the cam
114
, the color indicating portion
156
provided on the indicating plate
150
is indicated with colors on the indicating windows
158
,
160
,
162
of the front plate in order to inform a user about a present position of the breaker body
200
.
In the interlock apparatus of the draw out type air circuit breaker in accordance with the prior art, in order to connect the cradle
100
to the breaker body
200
, the breaker body
200
is placed on a guide frame
14
of the cradle
100
and is pushed in, accordingly the breaker body
200
is moved into the cradle
100
. When the lead screw
104
contacts to the screw pipe
106
according to the translocation of the breaker body
200
and a user rotates the lead screw
104
by using the handle, the lead screw proceeds into the screw pipe
106
while rotating.
Then, the two connection terminals
210
,
212
projected from the breaker body
200
are inserted into the two connectors
206
,
208
installed to the cradle
100
, accordingly the power source terminal
202
and the load terminal
204
are connected each other.
When the lead screw
104
proceeds, the lead bar
112
contacts to the one wall surface of the cradle
100
, herein the lead bar
112
moves in a direction opposite to the lead screw
104
. As described above, when the lead bar
112
retreats, it rotates the cam
114
while moving along the slot
118
of the cam
114
, by the rotation of the cam
114
the indicate plate
150
moves to the upper portion. Herein, a color indicating portion
156
provided on the indicating pla
Friedhofer Michael
LG Industrial Systems Co. Ltd.
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