Patent Grant
8330065
The present invention relates to a switchgear for opening/closing an electrical circuit and its operating mechanism and, more particularly, to a switchgear and its operating mechanism suitably configured for cutting off high-voltage current in short time periods.
In general, there are available, as an operating mechanism of a switchgear, one using a hydraulic operating force for large power and one using a spring operating force for middle/small output power. The former is referred to as “hydraulic operating mechanism” and the latter as “spring operating mechanism”. In recent years, the advancement of size reduction of an arc-extinguishing chamber of a gas-insulated circuit breaker which is a type of a switchgear allows fault current to be cut off with a smaller operating force, so that application of the spring operating mechanism becomes popular. However, a gas-insulated circuit breaker of extra high-voltage class requires high-speed operating capability called “2-cycle operation” that is capability of achieving cutoff within a time length corresponding to two-cycle time periods of alternating current. A conventional spring operating mechanism typically has operating capability equivalent to about 3-cycle operation, and it is not easy to realize the two-cycle cutoff capability due to poor responsiveness of a retention mechanism or retention control mechanism of a spring force.
A first type of conventional example of an operating mechanism of such a switchgear is disclosed in Japanese Patent Application Laid-Open Publications No. 11-213824 (FIGS. 1 and 7) and No. 2000-40445 (FIGS. 1 and 3), the entire contents of which are incorporated herein by reference. In operation mechanisms disclosed in these documents, a force of a cutoff spring is retained by a retention mechanism constituted by a latch, O-prop (opening-hook lever), and a catch through an output lever. In this configuration, when a trip current is applied to a solenoid serving as a retention control mechanism, a plunger of the solenoid activates the catch to allow the engagement between the catch and prop to be released, which releases the engagement between the output lever and the latch to rotate the output lever to release the cutoff spring force, thereby achieving cutoff operation.
A second type of conventional example of the switchgear operating mechanism is disclosed in Japanese Patent No. 3497866 (FIGS. 1 to 4), the entire content of which is incorporated herein by reference. In a spring operating mechanism disclosed in this document, a pull-out lever and a retention lever are provided for retaining a cutoff spring force. In this configuration, the retention lever is activated not by the cutoff spring force but by a force of an acceleration spring at the cutoff operation time so as to release the cutoff spring force.
In the first type of conventional example of the switchgear operating mechanism, operation for releasing the cutoff spring force (cutoff operation) is constituted by the following three steps: operation of the catch driven by excitation of the solenoid, operation of the O-prop, and operation of electrical contacts including the cutoff spring. The operational relationship between the above components is illustrated in
Time length from the start of application of the trip current until the operation of the O-prop is started along with the operation of the catch is assumed to be T1. Time length from the start of operation of the O-prop to the start of operation of the cutoff spring is assumed to be T2. Time length from the start of operation of the cutoff spring until the cutoff spring reaches its contact opening point is assumed to be T3. Assuming that contact opening time is T0,
T0=T1+T2+T3 (1)
is satisfied.
In order to realize 2-cycle operation, it is necessary to reduce contact opening time T0 to a given value. Thus, in a typical spring operating mechanism, operations of the components from the catch to the cutoff spring, which occur after the trip current application, are not started simultaneously. That is, the catch operates to some degree to release the engagement between itself and the O-prop to thereby allow operation of the O-prop to be started, and the cutoff spring starts operating after the O-prop operates to some degree. Thus, a mechanism that-retains a cutoff spring force operates in a stepwise manner, so that it is necessary to reduce respective time lengths T1, T2, and T3 in order to reduce T0.
However, since the cutoff spring force is determined by the weight of a movable portion of the arc-extinguishing chamber, opening speed, and drive energy, there is a limit to a reduction of T3. With regard to T2, weight reduction of the O-prop and increase in a force (retention force) of retaining the cutoff spring force allow high-speed operation of the O-prop. However, when the retention force is increased, the size of the O-prop needs to be increased for strength, which limits the weight reduction of the O-prop. It follows that there occurs a limit in the improvement in operation speed relying on the increase in the retention force. Further, when the retention force is increased, a large force is applied to the engagement portion between the O-prop and the catch, so that there occurs a need to increase the size of the catch for strength and to provide a solenoid having a large electromagnetic power for activating the catch.
At present, an excitation method using a large-sized condenser is adopted for obtaining a large power of the solenoid. However, the upper limit value for a current value flowing to the solenoid is specified in the standard, so that there is a limit in the improvement in the output power of the solenoid. As described above, it is difficult to reduce the contact opening time in the conventional spring operating mechanism.
Also in the second type of conventional example, operation for releasing the cutoff spring force is constituted by the following three steps: operation of a pull-off hook driven by an electromagnet; simultaneous operation of a reset lever, acceleration spring, and a retention lever; and simultaneous operation of a pull-off lever and a cutoff spring. In this example, the direction of a retention force (pressuring force) of the cutoff spring is made substantially coincident with the rotation center of the retention lever, thereby reducing a force required for the operation of the retention lever.
Further, the speed of movement of the retention lever, which is included in the above second step, is made higher by the accelerating spring to thereby reduce the operation time. However, it is physically difficult to reduce the operation time of the second step to zero and, therefore, it is difficult to significantly reduce the entire contact opening time, also in terms of the problems described in the first example.
Further, the direction of a pressuring force to a portion at which the pull-off lever and the retention lever are engaged with each other is made substantially coincident with the rotation center of the retention lever, so that when an external vibration is applied to the retention lever to force the same to vibrate, the pull-off lever is rotated in the cutoff operation direction, and the cutoff operating mechanism may start operating without a cutoff command.
Further, the direction of the pressuring force may fluctuate with respect to the rotation center of the retention lever due to deformation of the engagement surface between a roller provided on the pull-off lever and the retention lever, so that when the pressuring force acts in the cutoff operation direction of the retention lever, the pull-off lever may be released without a cutoff command.
Further, although not described in Japanese Patent No. 3497866, it is just conceivable that the retention lever operates in the cutoff direction due to an impact force applied when the roller pushes aside the retention lever for reengagement in the closing operation to allow the cutoff operation to be started without a cutoff command. As described above, in the second example, it is difficult to significantly reduce the contact opening time and it is likely that a retention state of the cutoff spring becomes unstable.
The present invention has been made to solve the above problems, and an object thereof is to provide a switchgear for opening/closing an electrical circuit and its operating mechanism in which retention/release of the cutoff spring force is performed by a combination of a latch and its lock mechanism to reduce a time period for the cutoff spring force to be released so as to significantly reduce the entire contact opening time and, at the same time, stability and reliability of a retention state of the cutoff spring force are improved.
In order to achieve the object, according to an aspect of the present invention there is provided a switchgear operating mechanism for reciprocatively driving a movable contact of a switchgear so as to shift the switchgear between a cutoff state and a closed state, the operating mechanism comprising: a frame; a closing shaft which is rotatably disposed relative to the frame; main lever which is rotatably fixed to the closing shaft and which can be swung in conjunction with the movable contact; a cutoff spring which is disposed such that it accumulates energy when the switchgear operating state is shifted from the cutoff state to the closed state in accordance with rotation of the closing shaft while it discharges its accumulated energy when the switchgear operating state is shifted from the closed state to the cutoff state; a sub-shaft which is rotatably disposed relative to the frame so as to be positioned around a rotation axis substantially parallel to a rotation axis of the closing shaft; a sub-lever which is swingably fixed to the sub-shaft; a main-sub connection link which rotatably connects a leading end of the sub-lever and the main lever; a cam mechanism which swings the sub-shaft in accordance with a rotation of the closing shaft; a latch lever which is swingably fixed to the sub-shaft; a roller which is rotatably fixed to a leading end of the latch lever; a latch which is disposed so as to be rotated relative to the frame around a rotation axis substantially parallel to the rotation axis of the closing shaft; a kick lever which is disposed so as to be rotated relative to the latch around a rotation axis substantially parallel to the rotation axis of the latch and has a through hole therein; a lock lever which is disposed so as to be rotated relative to the latch around a different rotation axis substantially parallel to the rotation axis of the latch; a latch return spring which biases the latch so as to rotate the latch in a predetermined direction; a lock return spring which biases the lock lever and the kick lever so as to rotate the lock lever and the kick lever in a predetermined direction; stopper which is fixed to the frame so as to restrict the rotation of the biasing direction of the lock lever and the latch; and a connection pin which is attached to the lock lever so as to be moved and rotated in the through hole formed in the lock lever relative to the through hole, wherein in the closed state, the roller pushes the leading end of the latch in an opposite direction to the biasing direction of the latch return spring and causes the leading end of the lock lever to be engaged with the stopper to stop the operation of the latch, and in a state where the switchgear operating state is shifted from the closed state to the cutoff state, the lock lever is pulled so as to be rotated in an opposite direction to the biasing direction of the lock return spring and the latch is pulled in an opposite direction to the biasing direction of the latch return spring to release an engagement between the roller and the leading end of the latch, which causes the cutoff spring to discharge its energy to rotate the sub-shaft and the main lever.
According to another aspect of the present invention there is provided a switchgear operating mechanism for reciprocatively driving a movable contact of a switchgear so as to shift the switchgear between a cutoff state and a closed state, the operating mechanism comprising: a frame; a closing shaft which is rotatably disposed relative to the frame; a main lever which is rotatably fixed to the closing shaft and which can be swung in conjunction with the movable contact; a cutoff spring which is disposed such that it accumulates energy when the switchgear operating state is shifted from the cutoff state to the closed state in accordance with rotation of the closing shaft while it discharges its accumulated energy when the switchgear operating state is shifted from the closed state to the cutoff state; a sub-shaft which is rotatably disposed relative to the frame so as to be positioned around a rotation axis substantially parallel to a rotation axis of the closing shaft; a sub-lever which is swingably fixed to the sub-shaft; a main-sub connection link which rotatably connects a leading end of the sub-lever and the main lever; a cam mechanism which swings the sub-shaft in accordance with a rotation of the closing shaft; a latch lever which is swingably fixed to the sub-shaft; a roller which is rotatably fixed to a leading end of the latch lever; a latch which is disposed so as to be rotated relative to the frame around a rotation axis substantially parallel to the rotation axis of the closing shaft; a lock lever which is disposed so as to be rotated relative to the frame around a rotation axis substantially parallel to the rotation axis of the latch; a latch return spring which biases the latch so as to rotate the latch in a predetermined direction; a lock lever return spring which biases the lock lever in a direction opposite to the biasing direction of the latch return spring; and a stopper which is fixed to the frame so as to restrict the rotation of the biasing direction of the lock lever return spring of the lock lever, wherein in the closed state, the roller pushes the leading end of the latch in a direction opposite to the biasing force of the latch return spring, and in a state where the switchgear operating state is shifted from the closed state to the cutoff state, the lock lever is pulled so as to allow the latch to be rotated in an opposite direction to the biasing direction of the latch return spring to release an engagement between the roller and the leading end of the latch, which causes the cutoff spring to discharge its energy to rotate the sub-shaft.
According to another aspect of the present invention there is provided a switchgear having a movable contact that can be moved in a reciprocating manner and an operating mechanism that reciprocatively drives the movable contact and configured to be shifted between a cutoff state and a closed state by the movement of the movable contact, the operating mechanism comprising: a frame; a closing shaft which is rotatably disposed relative to the frame; a main lever which is rotatably fixed to the closing shaft and which can be swung in conjunction with the movable contact; a cutoff spring which is disposed such that it accumulates energy when the switchgear operating state is shifted from the cutoff state to the closed state in accordance with rotation of the closing shaft while it discharges its accumulated energy when the switchgear operating state is shifted from the closed state to the cutoff state; a sub-shaft which is rotatably disposed relative to the frame so as to be positioned around a rotation axis substantially parallel to a rotation axis of the closing shaft; a sub-lever which is swingably fixed to the sub-shaft; a main-sub connection link which rotatably connects a leading end of the sub-lever and the main lever; a cam mechanism which swings the sub-shaft in accordance with a rotation of the closing shaft; a latch lever which swingably fixed to the sub-shaft; a roller which is rotatably fixed to a leading end of the latch lever; a latch which is disposed so as to be rotated relative to the frame around a rotation axis substantially parallel to the rotation axis of the closing shaft; a kick lever which is disposed so as to be rotated relative to the latch around a rotation axis substantially parallel to the rotation axis of the latch; a lock lever which is disposed so as to be rotated relative to the latch around a different rotation axis substantially parallel to the rotation axis of the latch; a latch return spring which biases the latch so as to rotate the latch in a predetermined direction; a lock return spring which biases the lock lever and the kick lever so as to rotate the lock lever and the kick lever in a predetermined direction; a stopper which is attached to the frame so as to restrict the rotation of the biasing direction of the lock lever and the latch; and a hole disposed in the kick lever so as to be engaged with a pin disposed on the lock lever, wherein in the closed state, the roller pushes the leading end of the latch in an opposite direction to the biasing direction of the latch return spring and causes the leading end of the lock lever to be engaged with the stopper to stop the operation of the latch, and in a state where the switchgear operating state is shifted from the closed state to the cutoff state, the lock lever is pulled so as to allow the lock lever to be rotated in an opposite direction to the biasing direction of the lock return spring and the latch is pulled in an opposite direction to the biasing direction of the latch return spring to release an engagement between the roller and the leading end of the latch, which causes the cutoff spring to discharge its energy to rotate the sub-shaft and the main lever.
According to another aspect of the present invention there is provided a switchgear having a movable contact that can be moved in a reciprocating manner and an operating mechanism that reciprocatively drives the movable contact and configured to be shifted between a cutoff state and a closed state by the movement of the movable contact, the operating mechanism comprising: a frame; a closing shaft which is rotatably disposed relative to the frame; a main lever which is rotatably fixed to the closing shaft and which can be swung in conjunction with the movable contact; a cutoff spring which is disposed such that it accumulates energy when the switchgear operating state is shifted from the cutoff state to the closed state in accordance with rotation of the closing shaft while it discharges its accumulated energy when the switchgear operating state is shifted from the closed state to the cutoff state; a sub-shaft which is rotatably disposed relative to the frame so as to be positioned around a rotation axis substantially parallel to a rotation axis of the closing shaft; a sub-lever which is swingably fixed to the sub-shaft; a main-sub connection link which rotatably connects a leading end of the sub-lever and the main lever; a cam mechanism which swings the sub-shaft in accordance with a rotation of the closing shaft; a latch lever which swingably fixed to the sub-shaft; a roller which is rotatably fixed to a leading end of the latch lever; a latch which is disposed so as to be rotated relative to the frame around a rotation axis substantially parallel to the rotation axis of the closing shaft; a lock lever which is disposed so as to be rotated relative to the frame around a rotation axis substantially parallel to the rotation axis of the latch; a latch return spring which biases the latch so as to rotate the latch in a predetermined direction; a lock lever return spring which biases the lock lever in a direction opposite to the biasing direction of the latch return spring; and a stopper which is fixed to the frame so as to restrict the rotation of the biasing direction of the lock lever return spring of the lock lever, wherein in the closed state, the roller pushes the leading end of the latch in a direction opposite to the biasing force of the latch return spring, and in a state where the switchgear operating state is shifted from the closed state to the cutoff state, the lock lever is pulled so as to allow the latch to be rotated in an opposite direction to the biasing direction of the latch return spring to release an engagement between the roller and the leading end of the latch, which causes the cutoff spring to discharge its energy to rotate the sub-shaft.
The above and other features and advantages of the present invention will become apparent from the discussion hereinbelow of specific, illustrative embodiments thereof presented in conjunction with the accompanying drawings, in which:
Embodiments of an operating mechanism of a switchgear according to the present invention will be described below with reference to the accompanying drawings.
First, with reference to
In
A cutoff spring 12 has one end fixed to an attachment surface 10d of the frame 14 and the other end fitted to a cutoff spring receiver 16. A damper 17 is fixed to the cutoff spring receiver 16. In the damper 17, a fluid is encapsulated and a piston 17a is provided so as to translationally slide. One end of the damper 17 is fixed to a cutoff spring link 15, which is rotatably attached to a pin 11a of the main lever 11.
A sub-shaft 70 is rotatably disposed relative to the frame 14, and a sub-lever 71 is fixed to the sub-shaft 70. A pin 71a is disposed at the leading end of the sub-lever 71. A pin 11d disposed on the main lever 11 and the pin 71a are connected by a main-sub connection link 80. A latch lever 72 is fixed to the sub-shaft 70, and a roller 72a is rotatably fitted to the leading end of the latch lever 72. Further, a cam lever 73 is fixed to the sub-shaft 70, and a roller 73a is rotatably fitted to the leading end of the cam lever 73.
A closing spring 13 has one end fixed to an attachment surface 10d of the frame 14 and the other end fixed to a closing spring receiver 18. A pin 18a is disposed on the closing spring receiver 18. The pin 18a is connected to a pin 82a of a closing lever 82 which is fixed to the end portion of the closing shaft 81 through a closing link 83. A closing cam 84 is fixed to the closing shaft 81 and releasably engaged with the roller 73a in accordance with the rotation of the closing shaft 81.
A tab 82b is disposed at one end of the closing lever 82 and is releasably engaged with a half-column portion 62a provided in an anchoring lever 62 for closing which is rotatably disposed relative to the frame 14. Further, a return spring 62b is disposed at one end of the anchoring lever 62 for closing. The other end of the return spring 62b is fixed to the frame 14. The return spring 62b is a compression spring and the spring force thereof always acts on the anchoring lever 62 for closing as a clockwise torque. However, the rotation of the anchoring lever 62 is restricted by an engagement between a plunger 22a of an electromagnetic solenoid 22 for closing which is fixed to the frame 14 and the anchoring lever 62 for closing.
In the cutoff state illustrated in
A two-forked support portion 90b is formed at the leading end of an anchoring lever 90. The support portion 90b is engaged with a stopper 14b which is fixed to the frame 14, which fixes the position of the anchoring lever 90 relative to the frame 14.
A latch 91 is rotatably disposed around a latch axis pin 100 which is fixed to the end portion of the anchoring lever 90. A latch return spring 91a is disposed between the anchoring lever 90 and the latch 91. The latch return spring 91a always generates a clockwise torque for the latch 91. The clockwise rotation of the latch 91 is restricted by an abutment between a stopper pin (stopper) 90a disposed on the anchoring lever 90 and the latch 91. A leading end 102 of the latch 91 is formed by a substantially cylindrical surface, and the center axis position of the cylindrical surface falls within a range between the rotation center of the latch 91, (i.e., center axis of the latch axis pin 100) and position spaced from the center axis of the latch axis pin 100 on the stopper 90a side by a distance corresponding to the radius of the latch axis pin 100.
A kick lever 51 is rotatably disposed around a rotary shaft 51a which is fixed to the latch 91. A protrusion portion 51c to be described later is formed in the kick lever 51. Further, a substantially rectangular through hole 51d is formed in the kick lever 51.
A lock lever 52 is rotatably disposed around a rotary shaft 52a which is fixed to the latch 91. A connection pin 52d is disposed on the lock lever 52, and the kick lever 51 and the lock lever 52 are connected to each other through an engagement between the connection pin 52d and a through hole 51d. The through hole 51d has a size allowing the connection pin 52d to move and rotate to some degree in the through hole 51d relative to the same.
A lock return spring 52c is disposed around the connection pin 52d. The lock return spring 52c has one end anchored to the rotary shaft 52a and the other end anchored to a pin 51b disposed on the kick lever 51 and always generates a clockwise torque for the lock lever 52. For the kick lever 51, the lock return spring 52c always generates a counterclockwise torque.
A torque generated by the lock return spring 52c is restricted by an abutment between a cut portion 52b formed at one end of the lock lever 52 and the stopper 90a. The rotation of the kick lever 51 is restricted by an abutment between the through hole 51d and the connection pin 52d. In the closed state illustrated in
Since the cut portion 52b is engaged with the stopper pin 90a in the closed state illustrated in
A pull-off link mechanism has a pull-off link 53 and a pull-off lever 54 rotatably and translationally engaged with one end of the pull-off link 53. A pin 52e disposed on the lock lever 52 and the end portion of the pull-off link 53 is connected in a rotatable manner. The pull-off link 53 has an elongated hole 53a at the engagement portion with the pull-off lever 54. A pin 54b is disposed on the pull-off lever 54. The pin 54b is engaged with the elongated hole 53a, allowing the pin 54b and the elongated hole 53a to be moved and rotated relative to each other within the range of the elongated hole 53a. The pull-off lever 54 is rotatably disposed relative to the frame 14 and always receives a clockwise torque by a pull-off return spring 54a.
The leading end of a plunger 21a of an electromagnetic solenoid 21 for cutoff which is fixed to the frame 14 is releasably engaged with the pull-off lever 54, which restricts the torque of the pull-off return spring 54a and causes the pull-off lever 54 to be rotated in the counterclockwise direction upon input of a cutoff command.
In the closed state, the main lever 11 always receives a clockwise torque by an expanding spring force of the cutoff spring 12. The force transmitted to the main lever 11 is then transmitted to the sub-lever 71 through the main-sub connection link 80. The transmitted force becomes a torque for always rotating the sub-lever 71 in the counterclockwise direction. This counterclockwise torque is supplied also to the latch lever 72. However, in the closed state, the leading end 102 of the latch 91 and the roller 72a are engaged with each other to restrict the counterclockwise rotation of the latch lever 72. Accordingly, the subsequent members from the sub-lever 71 to the cutoff spring 12 maintain their static state.
In the present embodiment, the rotation shafts, such as the closing shaft 81 and the sub-shaft 70, and axes of the respective pins are parallel to each other.
(Cutoff Operation)
In the present embodiment having the configuration described above, a cutoff operation from the closed state illustrated in
The pull-off link 53 rotates the latch 91 in the counterclockwise direction through the lock lever 52, which releases an engagement between the roller 72a and the leading end 102 of the latch 91. The latch lever 72 receives a counterclockwise torque from the cutoff spring 12, so that it is rotated in the counterclockwise direction while pushing the latch 91. At this time, the elongated hole 53a moves along the pin 54b, so that the pull-off link 53 and the pull-off lever 54 operate independently of each other. In this state, the protrusion portion 51c of the kick lever 51 has been moved to the pull-off lever 54 side by the rotation of the lock lever 52, so that it is not engaged with the roller 72a. This state is illustrated in
When an engagement between the latch 91 and the roller 72a is released in
When the cutoff spring 12 is displaced by a given distance, the piston 17a abuts the stopper 14a fixed to the frame 14 to generate a braking power of the damper 17 to thereby stop the movement of the cutoff spring 12. The movements of the link levers connected to the cutoff spring 12 are accordingly stopped, thereby completing the cutoff operation. This state is illustrated in
(Closing Operation)
Next, a closing operation from the cutoff state illustrated in
When the rotation of the sub-lever 71 is transmitted to the main lever 11, the main lever 11 is rotated in the counterclockwise direction (denoted by an arrow N). Then, the link mechanism 6 and the movable contact 200 connected to the link mechanism 6 are moved to the left to start the closing operation. The cutoff spring 12 is compressed in association with the rotation of the main lever 11 to accumulate energy to establish an engagement between the roller 72a and the latch 91 once again, thereby completing the closing operation.
When the latch lever 72 is rotated in the clockwise direction in a state where the operation is shifted from the cutoff state illustrated in
When an engagement between the closing cam 84 and the roller 73a is released, the latch 91 is returned to substantially the same position as that in the closed state by the torque of the latch return spring 91a. At this time, the lock lever 52 and the kick lever 51 are also returned to substantially the same position as those in the closed state by the torque clue to the lock return spring 52c. Further, the roller 72a is engaged with the leading end 102 of the latch 91 once again by the expanding force of the cutoff spring 12. At this reengagement operation, a force acting from the roller 72a to the latch 91 is directed to a range between substantially the rotation center of the latch 91 and position spaced from the rotation center of the latch 91 on the stopper 90a side by a distance corresponding to the radius of the latch axis pin 100. This is because that the leading end 102 of the latch 91 is formed by a substantially cylindrical surface, and the center position of the cylindrical surface falls within a range between substantially the rotation center of the latch 91, (i.e., center of the latch axis pin 100) and position spaced from the rotation center of the latch axis pin 100 on the stopper 90a side. Therefore, the latch 91 is pressed to rotate in the counterclockwise direction. However, the counterclockwise rotation of the latch 91 is restricted because the cut portion 52b of the lock lever 52 is engaged with the stopper 90a. Thus, a mechanism for locking the latch 91 is achieved.
According to the present embodiment, after the electromagnetic solenoid 21 for cutoff is excited upon input of a cutoff command, the cutoff operation is completed by two operation steps: a first operation step in which the latch 91 is directly driven through the pull-off lever 54, the pull-off link 53 and the lock lever 52 to release an engagement between the latch 91 and the roller 72a; and a second operation step in which the cutoff spring 12 operates. As described above, the number of operation steps for completing the cutoff operation is reduced from three (in the case of conventional spring operating mechanism) to two, thereby significantly reducing the cutoff operation time. This means that T2 is removed from the expression (1) representing the contact opening time, so that it is possible to reduce the contact opening time.
Further, the engagement surface of the leading end 102 of the latch 91 is formed by a substantially cylindrical surface, and the center position of the cylindrical surface falls within a range between substantially the rotation center of the latch, (i.e., center of the latch axis pin 100) and position spaced from the rotation center of the latch axis pin 100 on the stopper 90a side by a distance corresponding to the radius of the latch axis pin 100, so that a torque of the roller 72a acting on the latch 91 in the closed state becomes small. This allows a reduction of the size and the weight of the latch 91 and the lock lever 52 to thereby minimize a force required for releasing its engagement, which can minimize the size of the electromagnetic solenoid.
Further, by forming the protrusion portion 51c in the kick lever 51 and engaging the protrusion portion 51c with the roller 72a at the time of the closing, it is possible to realize an action for easily releasing an engagement between the lock lever 52 and the stopper 90a with a simple structure, contributing to size reduction of the latch 91.
The elongated hole 53a is disposed at one end of the pull-off link 53, and the pin 54b disposed on the pull-off lever 54 and the elongated hole 53a are engaged with each other. This configuration allows an engagement between the pull-off link 53 and the pull-off lever 54 to be released at the time when the latch 91 is returned to the closing state. As a result, it is possible to minimize the weight of the movable portion of the latch 91 to thereby reduce the time required for the latch 91 to return to the position of the closed state, enabling high speed operation.
There is a possibility that the connection pin 52d may abut the though hole 51d at the time when the kick lever 51 returns to the position of the closed state to apply an abutment force on the lock lever 52 to generate a torque in the lock lever 52. However, the connection pin 52d abuts the side surface of the through hole 51d at its rotary shaft 51a side, so that the abutment force is directed to the center of the rotary shaft 52a, preventing a torque from being generated.
First, with reference to
In
A cutoff spring 12 has one end fixed to an attachment surface 10d of the frame 14 and the other end fitted to a cutoff spring receiver 16. A damper 17 is fixed to the cutoff spring receiver 16. In the damper 17, a fluid is encapsulated and a piston 17a is provided so as to translationally slide. One end of the damper 17 is fixed to a cutoff spring link 15, which is rotatably attached to a pin 11a of the main lever 11.
A sub-shaft 70 is rotatably disposed relative to the frame 14, and a sub-lever 71 is fixed to the sub-shaft 70. A pin 71a is disposed at the leading end of the sub-lever 71. A pin 11d disposed on the main lever 11 and the pin 71a are connected by a main-sub connection link 80. A latch lever 72 is fixed to the sub-shaft 70, and a roller 72a is rotatably fitted to the leading end of the latch lever 72. Further, a cam lever 73 is fixed to the sub-shaft 70, and a roller 73a is rotatably fitted to the leading end of the cam lever 73.
A closing spring 13 has one end fixed to the attachment surface 10d of the frame 14 and the other end fixed to a closing spring receiver 18. A pin 18a is disposed on the closing spring receiver 18. The pin 18a is connected to a pin 82a of a closing lever 82 which is fixed to the end portion of the closing shaft 81 through a closing link 83. A closing cam 84 is fixed to the closing shaft 81 and releasably engaged with the roller 73a in accordance with the rotation of the closing shaft 81.
A tab 82b is disposed at one end of the closing lever 82 and is releasably engaged with a half-column portion 62a provided in an anchoring lever 62 for closing which is rotatably disposed on the frame 14. Further, a return spring 62b is disposed at one end of the anchoring lever 62 for closing. The other end of the return spring 62b is fixed to the frame 14. The return spring 62b is a compression spring and the spring force thereof always acts on the anchoring lever 62 for closing as a clockwise torque. However, the rotation of the anchoring lever 62 is restricted by an engagement between a plunger 22a of an electromagnetic solenoid 22 for closing, which is fixed to the frame 14, and the anchoring lever 62 for closing.
In the cutoff state illustrated in
A projecting support portion 390b is formed in an anchoring lever 390. The support portion 390b is engaged with a stopper 14b which is fixed to the frame 14, which fixes the position of the anchoring lever 390 relative to the frame 14.
A latch 391 is rotatably disposed around a latch axis pin 100 which is fixed to the end portion of the anchoring lever 390. A latch return spring 391a is disposed between the anchoring lever 390 and the latch 391. The latch return spring 391a always generates a clockwise torque for the latch 391. The clockwise rotation of the latch 391 is restricted by an abutment between a stopper pin (stopper) 390a disposed on the anchoring lever 390 and the latch 391. A leading end 102 of the latch 391 is formed by a substantially cylindrical surface, center position of the cylindrical surface substantially coincides with the rotation center of the latch 391, i.e., center axis of the latch axis pin 100 or falls within the radius of the latch axis pin 100.
A lock lever 352 is a V-shape plate and has, at its bent portion of the V-shape, a pin 352a, through which the lock lever 352 and the latch 391 are rotatably engaged with each other. An engagement portion 352b which is releasably engaged with the stopper pin 390a is formed at one end of the V-shape lock lever 352. A protrusion portion 352c to be described later is formed at the other end of the V-shape lock lever 352.
A counterclockwise torque is always applied to the lock lever 352 by a lock lever return spring 352e, and the lock lever 352 receives the torque when the engagement portion 352b abuts the stopper pin 390a.
In the closed state illustrated in
A pull-off link mechanism has a pull-off link 353 and a pull-off lever 354 movably and rotatably engaged with one end of the pull-off link 353. The pull-off link 353 has an elongated hole 353a which penetrates the engagement portion between itself and a pull-off lever pin 354b disposed on the pull-off lever 354. The pull-off lever pin 354b can be moved and rotated relative to the elongated hole 353a within the range of the elongated hole 353a. A lock lever pin 352d is disposed on the lock lever 352 and is rotatably engaged with the end portion of the pull-off link 353 at the opposite side to the elongated hole 353a. The pull-off lever 354 is rotatably disposed relative to the frame 14 and always receives a clockwise torque by a pull-off return spring 354a.
The leading end of a plunger 21a of an electromagnetic solenoid 21 for cutoff which is fixed to the frame 14 is releasably engaged with the pull-off lever 354, which causes the pull-off lever 354 to be rotated in the counterclockwise direction upon input of a cutoff command.
In the closed state, the main lever 11 always receives a clockwise torque by an expanding spring force of the cutoff spring 12. The force transmitted to the main lever 11 is then transmitted to the sub-lever 71 through the main-sub connection link 80. The transmitted force becomes a torque for always rotating the sub-lever 71 in the counterclockwise direction. This counterclockwise torque is supplied also to the latch lever 72. However, in the closed state, the leading end 102 of the latch 391 and the roller 72a are engaged with each other to restrict the counterclockwise rotation of the latch lever 72. Accordingly, the subsequent members from the sub-lever 71 to the cutoff spring 12 maintain their static state.
In the present embodiment, the rotation shafts, such as the closing shaft 81 and the sub-shaft 70, and the axes of the pins are parallel to each other.
(Cutoff Operation)
In the present embodiment having the configuration described above, a cutoff operation from the closed state illustrated in
The pull-off link 353 rotates the latch 391 in the counterclockwise direction through the lock lever 352, which releases an engagement between the roller 72a and the leading end 102 of the latch 391. The latch lever 72 receives a counterclockwise torque from the cutoff spring 12, so that it is rotated in the counterclockwise direction while pushing the latch 391. At this time, the pull-off link 353 moves while the elongated hole 353a and the pull-off lever pin 354b are engaged with each other, so that it operates independently of the pull-off lever 354. In this state, the protrusion portion 352c of the lock lever 352 has been shifted to the pull-off lever 354 side from the latch 391, so that it is not engaged with the roller 72a. This state is illustrated in
When an engagement between the latch 391 and the roller 72a is released in
When the cutoff spring 12 is displaced by a given distance, the piston 17a abuts the stopper 14a fixed to the frame 14 to generate a braking power of the damper 17 to thereby stop the movement of the cutoff spring 12. The movements of the link levers connected to the cutoff spring 12 are accordingly stopped, thereby completing the cutoff operation. This state is illustrated in
(Closing Operation)
Next, a closing operation from the cutoff state illustrated in
When the rotation of the sub-lever 71 is transmitted to the main lever 11, the main lever 11 is rotated in the counterclockwise direction (denoted by an arrow N). Then, the link mechanism 6 and the movable contact 200 connected thereto are moved to the left to start the closing operation. The cutoff spring 12 is compressed in association with the rotation of the main lever 11 to accumulate energy to establish an engagement between the roller 72a and the latch 391 once again, thereby completing the closing operation.
When the latch lever 72 is rotated in the clockwise direction in a state where the operation is shifted from the cutoff state illustrated in
When an engagement between the closing cam 84 and the roller 73a is released, the roller 72a is engaged with the leading end 102 of the latch 391 once again by the expanding force of the cutoff spring 12. At this reengagement operation, a force acting from the roller 72a to the latch 391 is directed to substantially the rotation center of the latch 391. This is because that the leading end 102 of the latch 391 is formed by a substantially cylindrical surface, and the center position of the cylindrical surface substantially coincides with the rotation center of the latch 391 (i.e., center axis of the latch axis pin 100). However, there is a possibility that the latch 391 is rotated in the counterclockwise direction due to lack of accuracy in the engagement surface, deformation of the engagement surface, or impact force at the time of engagement, to release the roller 72a from the latch 391. At this time, however, an engagement between the engagement portion 352b of the lock lever 352 and the stopper pin 390a have already been established by the lock lever return spring 352e, the lock lever 352 functions as a malfunction preventing mechanism to prevent the counterclockwise rotation of the latch 391.
According to the present embodiment, after the electromagnetic solenoid 21 for cutoff is excited upon input of a cutoff command, the cutoff operation is completed by two operation steps: a first operation step in which the latch 391 is directly driven through the pull-off lever 354 and pull-off link 353 to release an engagement between the latch 391 and the roller 72a; and a second operation step in which the cutoff spring 12 operates. As described above, the number of operation steps for completing the cutoff operation is reduced from three (in the case of conventional spring operating mechanism) to two, thereby significantly reducing the cutoff operation time. This means that T2 is removed from the expression (1) representing the contact opening time, so that it is possible to reduce the contact opening time.
Further, the lock lever 352 can prevent a disengagement of the latch 391 due to an external vibration or a change in the retention direction resulting from deformation of the leading end 102 of the latch 391, thereby increasing operational reliability of the spring operating mechanism.
Furthermore, the engagement surface of the leading end 102 of the latch 391 is formed by a substantially cylindrical surface, and the center position of the cylindrical surface substantially coincides with the rotation center of the latch (i.e., center axis of the latch axis pin 100), so that a torque of the roller 72a does not act on the latch 391 in the closed state. This allows size reduction of the latch 391 to thereby minimize a force required for releasing the engagement between the latch 391 and the roller 72a, which can minimize the size of the electromagnetic solenoid.
Further, by forming the protrusion portion 352c in the lock lever 352 and engaging the protrusion portion 352c with the roller 72a at the time of the closing, it is possible to realize an action for easily releasing an engagement between the engagement portion 352b of the lock lever 352 and the stopper pin 390a with a simple structure, contributing to size reduction of the latch 391.
Next, with reference to
The present embodiment is obtained by omitting the lock lever return spring 352e of
With the above configuration, it is possible to obtain the same effect as that in the second embodiment.
The embodiments described above are merely given as examples, and it should be understood that the present invention is not limited thereto. For example, although compression coil springs are used as the cutoff spring 12 and the closing spring 13 in the above embodiments, other elastic bodies, such as torsion coil springs, disc springs, spiral springs, plate springs, air springs, and the expanding springs may be used alternatively. Further, although coil springs or torsion coil springs are used as the return springs 91a, 52c, 54a, 391a, 352e, and 354a provided in the latches 91, 391, lock levers 52, 352 and the pull-off levers 54, 354, other elastic bodies such as disc springs, spiral springs, or plate springs may be used alternatively.
The present invention can also be applied to an apparatus having a plurality of cutoff springs or plurality of the closing springs.
Further, although the stopper pin (90a, 390a) for restricting the rotation of the lock lever (52, 352) also serves as a stopper for restricting the rotation of the latch (91, 391), in the above embodiments, the above functions may be provided separately.
Further, since the anchoring levers 90, 390 are fixed to the frame 14, they may be omitted. In this case, the stoppers 90a, 390a or the like are directly fixed to the frame 14. Further, the stoppers 90a, 390a may be integrated with the anchoring levers 90, 390 or the frame 14.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-195992 | Jul 2007 | JP | national |
This application is a continuation-in-part (CIP) application of International Application PCT/JP2008/001994, the entire content of which is incorporated herein by reference. This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2007-195992, filed in the Japanese Patent Office on Jul. 27, 2007, the entire content of which is incorporated herein by reference.
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| Number | Date | Country | |
|---|---|---|---|
| 20100126967 A1 | May 2010 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2008/001994 | Jul 2008 | US |
| Child | 12694874 | US |
