Electricity: circuit makers and breakers – Contact moved by sudden release of stored energy
Reexamination Certificate
2002-01-17
2003-08-26
Friedhofer, Michael A (Department: 2832)
Electricity: circuit makers and breakers
Contact moved by sudden release of stored energy,
Reexamination Certificate
active
06610949
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an improvement of operating apparatuses for switchgears like circuit breakers used as electric power switching devices installed in an electric power substation or in a switching station, for example.
A conventionally available operating apparatus for a circuit breaker, which is a typical example of switchgears, utilizes an elastic force exerted by a spring as an operating force.
FIGS. 32-35
show a conventional operating apparatus for a circuit breaker disclosed in Japanese Laid-open Patent Publication No. 63-304542, in which
FIG. 32
is a perspective view generally showing the construction of the operating apparatus for the circuit breaker, and
FIG. 33
is a constructional diagram of the operating apparatus for the circuit breaker of
FIG. 32
showing a state in which the circuit breaker is closed and torsion bars
29
,
35
,
28
,
34
for making and breaking a circuit are all energized (caused to store elastic restoring energy by twisting).
FIG. 34
is a constructional diagram of the operating apparatus for the circuit breaker of
FIG. 32
showing a state in which the circuit breaker is opened, the circuit-breaking torsion bars
28
,
34
are deenergized (caused to release elastic restoring energy by restoring the original shape), and the circuit-making torsion bars
29
,
35
are energized.
FIG. 35
is a constructional diagram of the operating apparatus for the circuit breaker of
FIG. 32
showing a state in which the circuit breaker is closed, the circuit-breaking torsion bars
28
,
34
are energized and the circuit-making torsion bars
29
,
35
are deenergized.
In these Figures, designated by the numeral
1
is a housing, designated by the numeral
24
is cylindrical body fixed to the housing
1
, and designated by the numerals
26
and
27
are rotatable levers fitted to pins (not shown) provided on an end surface of the cylindrical body
24
. Since the circuit-breaking torsion bars
28
,
34
are energized when the circuit-making torsion bars
29
,
35
are deenergized, the amount of energy stored in the circuit-making torsion bars
29
,
35
is made larger than the amount of energy stored in the circuit-breaking torsion bars
28
,
34
. One end of the circuit-breaking torsion bar
28
is fixed to the housing
1
while the other end of the circuit-breaking torsion bar
28
is fixed to the lever
26
. Also, one end of the circuit-breaking torsion bar
34
is fixed to a rotary shaft
32
while the other end of the circuit-breaking torsion bar
34
is fixed to the lever
26
as shown in FIG.
32
.
On the other hand, one end of the circuit-making torsion bar
29
is fixed to the housing
1
while the other end of the circuit-making torsion bar
29
is fixed to the lever
27
. Also, one end of the circuit-making torsion bar
35
is fixed to a rotary shaft
33
while the other end of the circuit-making torsion bar
35
is fixed to the lever
27
as shown in FIG.
32
. Referring to
FIG. 33
, designated by the numeral
37
is a closing lever fixed to the rotary shaft
33
. A counterclockwise turning force is exerted on the closing lever
37
by the circuit-making torsion bars
29
,
35
through the rotary shaft
33
. It is to be noted that the direction of rotation, as well as horizontal and vertical directions, is expressed as they appear in the relevant Figures unless otherwise mentioned in the following discussion.
Referring again to
FIG. 33
, designated by the numeral
2
is a cam shaft rotatably supported by the housing
1
, designated by the numeral
3
is a cam which is fixed to the cam shaft
2
and rotates together with the cam shaft
2
, designated by the numeral
13
is a pin provided on the cam
3
, and designated by the numeral
14
is a closing latch engaged with the pin
13
. Further, designated by the numeral
15
is a closing trigger meshed with the closing latch
14
, and designated by the numeral
16
is a closing electromagnet having a plunger
17
. Designated by the numeral
38
is a rotary shaft which is rotatably supported by the housing
1
and turned counterclockwise by an electric motor (not shown), designated by the numeral
39
is a small gear wheel which is fixedly mounted on the rotary shaft
38
, and designated by the numeral
40
is a large gear wheel which is fixedly mounted on the cam shaft
2
and engaged with the small gear wheel
39
. The large gear wheel
40
lacks teeth on one part of its periphery such that the large gear wheel
40
becomes disengaged from the small gear wheel
39
when the circuit-making torsion bars
29
,
35
are energized.
In
FIG. 33
, designated by the numeral
41
is a link which connects the closing lever
37
and the large gear wheel
40
to each other via pins provided on the closing lever
37
and the large gear wheel
40
. Designated by the numeral
36
is an interrupting lever fixedly mounted on the rotary shaft
32
on which a counterclockwise turning force is exerted by the circuit-breaking torsion bars
28
,
34
via the rotary shaft
32
. Designated by the numeral
8
is a pin provided on the interrupting lever
36
, and designated by the numeral
9
is a rotary member provided on the interrupting lever
36
. Designated by the numeral
18
is a tripping latch meshed with the pin
8
, wherein a clockwise turning force is exerted on the tripping latch
18
by a spring
43
.
Designated by the numeral
19
is a tripping trigger meshed with the tripping latch
18
, and designated by the numeral
20
is a tripping electromagnet having a plunger
21
. The plunger
21
is driven rightward as illustrated in
FIG. 33
when the tripping electromagnet
20
is excited, and the plunger
21
is caused to return to its original position by a reset spring (not shown) when the tripping electromagnet
20
is deenergized. Designated by the numeral
10
is an on-off switch having a stationary contact
12
and a movable contact
22
. The movable contact
22
is connected to the interrupting lever
36
via a link mechanism
23
and a rod
61
. Designated by the numeral
42
is a shock absorber connected to the interrupting lever
36
to alleviate shocks occurring when the movable contact
22
goes into contact with and comes apart from the stationary contact
12
.
Now, circuit-breaking and making operations of the aforementioned conventional operating apparatus for the circuit breaker are described, beginning with the circuit-breaking operation below.
Referring to
FIG. 33
, the interrupting lever
36
continuously receives the counterclockwise turning force exerted by the circuit-breaking torsion bars
28
,
34
, and this turning force is carried by the tripping trigger
19
via the tripping latch
18
. If the tripping electromagnet
20
is excited in this condition, the plunger
21
moves rightward, causing the tripping trigger
19
to turn clockwise and become disengaged from the tripping latch
18
. At this time, the tripping latch
18
is caused to turn counterclockwise by a reaction force exerted by the pin
8
and become released from the pin
8
. When the tripping latch
18
and the pin
8
are disengaged, the interrupting lever
36
turns counterclockwise, causing the movable contact
22
to move in a circuit-breaking direction and become separated from the stationary contact
12
. Shown in
FIG. 34
is the state in which the above-described circuit-breaking operation has been completed.
The circuit-making operation from the state shown in
FIG. 34
is carried out as described below. In
FIG. 34
, the cam
3
fixed to the cam shaft
2
is connected to the closing lever
37
via the cam shaft
2
, the large gear wheel
40
fixed to the cam shaft
2
and the link
41
, and a clockwise turning force is exerted on the cam
3
by the circuit-making torsion bars
29
,
35
. This turning force is carried by the closing trigger
15
via the closing latch
14
.
If the closing electromagnet
16
is excited in this condition, the plunger
17
moves rightward and hits against the closing trigger
15
, causing the closing trigger
15
Mori Tomohito
Nakajima Nobuya
Ohtsuka Kyoichi
Friedhofer Michael A
Mitsubishi Denki & Kabushiki Kaisha
Sughrue & Mion, PLLC
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