Interlock apparatus for vacuum circuit breaker

An interlock apparatus for a vacuum circuit breaker includes a pair of hindering units configured to allow or prevent a motion of a breaker body to an connection position or a disconnection position; a pair of first interlock bars configured to change a width of the breaker body to be greater than the predetermined spacing distance of the hindering units in a first position where the first interlock bars are spaced from each other, or to change the width of the breaker body to be smaller than the predetermined spacing distance; and a second interlock bar vertically movable to an up position and a down position, the up position for moving the first interlock bars to the first position, and the down position for returning the first interlock bars to the second position by being separated from the interposed position between the first interlock bars.

CROSS-REFERENCE TO RELATED APPLICATION

Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Patent Application No. 10-2011-0018191, filed on Feb. 28, 2011, the contents of which are hereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vacuum circuit breaker, and more particularly, to an interlock apparatus for a vacuum circuit breaker capable of preventing the occurrence of an accident by preventing a breaker body from moving to a connection position (in other words push-in position) for connection to terminals of an enclosure from a disconnection position (in other words draw-out position) for separation from the terminals of the enclosure, or by preventing the breaker body from moving to the disconnection position from the connection position, in a state that a closing spring for a closing operation is charged with elastic energy.

2. Background of the Invention

Generally, a circuit breaker for protecting an electric power circuit and an electric load devices by automatically breaking the circuit upon detection of an abnormal current on the circuit or for switching the electric power circuit, may be categorized into a low voltage circuit breaker for a low voltage less than several hundreds of volts, and a high voltage circuit breaker for a high voltage more than several hundreds of volts according to the size of a rated voltage.

A vacuum circuit breaker is the high voltage circuit breaker and may be categorized into a fixed type vacuum circuit breaker, and a movable type vacuum circuit breaker movable in an enclosure such as an electric power distribution board so as to be connected to or disconnected from the enclosure.

The movable type vacuum circuit breaker is more used worldwide than the fixed type vacuum circuit breaker, since a breaker body can be separated from terminals of an enclosure for test, repair and replacement (movable to a disconnection position) and can be connected to the terminals of the enclosure after test, repair and replacement (movable to a connection position).

For the connection or disconnection, the breaker body is provided with wheels together with a driving device at a lower part thereof.

The draw-out type vacuum circuit breaker has a closing position (ON′ position) for supplying an electric power in a state an electric circuit is closed, and a breaking position (‘OFF’ position or ‘TRIP’ position) for breaking the electric power supply by making an electric circuit be opened state. Here, the vacuum circuit breaker may be movable to the closing position or the breaking position, by extension of a closing spring or a trip spring for discharging charged energy, respectively. In the occurrence of an abnormal current on the electric power circuit, the circuit has to be instantaneously interrupted. Accordingly, the closing spring and the trip spring have very high elastic energy, respectively.

In the draw-out type vacuum circuit breaker, the breaker body may be separated from terminals of an enclosure for test, repair and replacement, or may be connected to the terminals of the enclosure after test, repair and replacement.

If the closing spring of the vacuum circuit breaker is in a charged state while the breaker body is connected to or disconnected from the enclosure, the elastic energy charged in the closing spring may be discharged. This may result in injury to a user.

SUMMARY OF THE INVENTION

Therefore, a purpose of the present disclosure is to provide an interlock apparatus for a vacuum circuit breaker capable of preventing the occurrence of an accident by preventing a breaker body from moving to a connection position for connection to terminals of an enclosure from a disconnection position for separation from the terminals of the enclosure, or by preventing the breaker body from moving to the disconnection position from the connection position, in a state that a closing spring is charged.

In a vacuum circuit breaker comprising:

an enclosure having terminals connectable to an electric power source or an electric load; a breaker body movable to a connection position for connection to the terminals of the enclosure and to a disconnection position for disconnection from the terminals of the enclosure; and

a closing spring installed in the breaker body and having an extended position and a contracted position, the extended position where elastic energy is charged to move the breaker body to a closing position, and the contracted position where elastic energy is discharged,

to achieve the purpose of the present disclosure, there is provided an interlock apparatus for the vacuum circuit breaker comprising:

a pair of hindering units fixed to both side walls of the enclosure with a predetermined spacing distance, and configured to allow or prevent a motion of the breaker body to the connection position or the disconnection position by passing only an object having a width smaller than the predetermined spacing distance therethrough;

a pair of first interlock bars horizontal-movably installed at the breaker body, and configured to change a width of the breaker body to be greater than the predetermined spacing distance of the hindering units in a first position where the first interlock bars are spaced from each other, or to change the width of the breaker body to be smaller than the predetermined spacing distance of the hindering units in a second position where the first interlock bars return to be close to each other; and

a second interlock bar vertical-movably installed at the breaker body, and up-down movable to an up position and a down position by a pressing or releasing operation of the closing spring according to the extended or contracted position, the up position for moving the first interlock bars to the first position in a pressing manner by being interposed between the first interlock bars, and the down position for returning the first interlock bars to the second position by being separated from the interposed position between the first interlock bars.

According to one aspect of the present disclosure, the interlock apparatus for a vacuum circuit breaker further comprise:

a horizontal slit portion horizontally formed at each of the first interlock bars, and configured to limit a horizontal moving distance of the first interlock bars;

a first guide bolt fixed to a predetermined position of the breaker body, and configured to guide a horizontal motion of the first interlock bars by passing through the horizontal slit portion; and

a first return spring having one end supported by the first guide bolt and another end supported by the first interlock bars, and configured to provide elastic force to the first interlock bars such that the first interlock bars return to the second position.

According to another aspect of the present disclosure, the interlock apparatus for a vacuum circuit breaker further comprise:

a vertical slit portion vertically formed at the second interlock bar, and configured to limit a vertical moving distance of the second interlock bar;

a second guide bolt fixed to a predetermined position of the breaker body, and configured to guide a vertical motion of the second interlock bar by passing through the vertical slit portion; and

a second return spring having one end supported by the second interlock bar and another end supported by the breaker body, and configured to provide elastic force to the second interlock bar such that the second interlock bar returns to a down position.

According to another aspect of the present disclosure, a contact surface of the second interlock bar with the first interlock bar may be configured as an inclined surface.

According to still another aspect of the present disclosure, the interlock apparatus for a vacuum circuit breaker further comprise a pair of guide pins fixed to predetermined positions of the breaker body, facing each other with a spacing distance therebetween, and configured to allow a vertical motion of the second interlock bar through the space therebetween.

According to still another aspect of the present disclosure, the pair of hindering units may be configured as a pair of protrusion members protruding from both side walls of the enclosure, and facing each other.

According to still another aspect of the present disclosure, the second interlock bar includes:

a pair of operation limitation surfaces vertically formed at an upper part of the second interlock bar so as to face each other, and configured to limit a horizontal moving distance of the first interlock bars; and

a pair of inclined surfaces upward extending from the operation limitation surfaces, and upward inclined such that the second interlock bar has a decreased width.

According to still another aspect of the present disclosure, a contact surface of the first interlock bar with the second interlock bar may be configured as an inclined surface or a curved surface.

Further scope of applicability of the present application will become more apparent from the present disclosure given hereinafter. However, it should be understood that the present disclosure and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a configuration and an operation of an interlock apparatus for a vacuum circuit breaker according to the present invention will be explained with reference to the attached drawings.

Firstly, a configuration and an operation of a vacuum circuit breaker including an interlock apparatus according to the present disclosure will be explained with reference toFIGS. 1 to 4.

Referring toFIG. 1orFIG. 2, a vacuum circuit breaker including an interlock apparatus according to the present disclosure comprises an enclosure400and a breaker body100.

The enclosure400is a means for accommodating the breaker body100movably therein, and has terminals connectable to an electric power source or electric load of an external electric circuit. The terminals may include an external terminal portion connected to the electric power source or electric load, and an inner terminal portion connected to a terminal portion (not shown) of the breaker body100.

Reference numeral401ofFIG. 1designates an installation space in the enclosure400where the breaker body100is movably installed back and forth.

The breaker body100is movable, in the enclosure400, to a connection position for connection to the terminals, and a disconnection position for disconnection from the terminals. As well-known, the breaker body100may include vacuum interrupters, each having a movable contact and a fixed contact in a vacuum container and provided for each phase (pole) of three-phases (three-poles) alternating current (AC), and a driving mechanism for driving the movable contacts of the vacuum interrupters to a circuit closing position or a circuit opening position. The driving mechanism may include a closing spring110ofFIG. 4, a trip spring (not shown), a plurality of links and levers, latches.

The closing spring110ofFIG. 4is installed in the breaker body100, and has an extended position where elastic energy is charged and a contracted position where elastic energy is discharged. Here, the elastic energy is charged for implementation of a closing position where the movable contact of the vacuum interrupter of the breaker body100contacts the fixed contact.

As shown inFIGS. 5 and 6, the closing spring110is installed in an upright state.

Reference numeral111ofFIG. 4designates an operation end of the closing spring110, and120designates a lever rotatable to connect the aforementioned links and levers to the closing spring110.

The interlock apparatus according to the present disclosure includes a pair of hindering units410, a pair of first interlock bars300, and a second interlock bar200.

The pair of hindering units410are fixed to both side walls of the enclosure400with a predetermined spacing distance (refer to ‘d1’ inFIG. 6), and is configured to allow or prevent a motion of the breaker body100to an connection position or a disconnection position by passing only an object having a width smaller than the predetermined spacing distance (d1) therethrough.

The pair of hindering units410may be configured as a pair of protrusion members protruding from both side walls of the enclosure400, and facing each other. Referring toFIG. 5, each of the hindering units410may be configured as an approximate rectangular parallelepiped shape having an open bottom and an open side surface. And, each of the hindering units410may have a pair of flanges provided with fixing bolt openings for fixing the hindering units410to the both side walls of the enclosure400.

Reference numeral411ofFIG. 5designates facing surfaces of the pair of hindering units410.

As shown inFIG. 3, the pair of first interlock bars300are installed at the breaker body100so as to be movable in a horizontal direction. The first interlock bars300are configured to change a width of the breaker body100to be greater than the predetermined spacing distance (d1) of the hindering units410in a first position where the first interlock bars300are spaced from each other, and to change the width of the breaker body100to be smaller than the predetermined spacing distance (d1) of the hindering units410in a second position where the first interlock bars300return to be close to each other.

The second interlock bar200is up-down movable to an up position and a down position by a pressing or releasing operation of the closing spring110according to the extended or contracted position. Here, the up position indicates a position for moving the first interlock bars300to the first position in a pressing manner as the second interlock bar200is interposed between the first interlock bars300, and the down position indicates a position for returning the first interlock bars300to the second position as the second interlock bar200is separated from the interposed position between the first interlock bars300. The second interlock bar200is installed at the breaker body100so as to be vertically movable.

As shown in the two-dot chain line ofFIG. 3, the interlock apparatus according to the present disclosure further includes a horizontal slit portion (H1), a first guide bolt (B1) and a first return spring (RS1).

The horizontal slit portion (H1) is horizontally formed at each of the first interlock bars30, and is configured to limit a horizontal moving distance of the first interlock bars300. In this preferred embodiment, the horizontal slit portion (H1) may be formed in two at each of the first interlock bars300.

The first guide bolt (B1) is fixed to a predetermined position of the breaker body100, and is configured to guide a horizontal motion of the first interlock bars300by passing through the horizontal slit portion (H1).

The first return spring (RS1) has one end supported by the first guide bolt (B1) and another end supported by the first interlock bars300, and is configured to provide elastic force to the first interlock bars300so that the first interlock bars300may return to the second position.

According to another embodiment of the present disclosure, as shown inFIG. 3, the interlock apparatus for a vacuum circuit breaker further includes a vertical slit portion (H2), a second guide bolt (B2) and a second return spring (RS2).

The vertical slit portion (H2) is vertically formed at the second interlock bar200, and is configured to limit a vertical moving distance of the second interlock bar200.

The second guide bolt (B2) is fixed to a predetermined position of the breaker body100, and is configured to guide a vertical motion of the second interlock bar200by passing through the vertical slit portion (H2).

The second return spring (RS2) has one end supported by the second interlock bar200and another end supported by the breaker body100, and is configured to provide elastic force to the second interlock bar200so that the second interlock bar200may return to the down position.

As shown in the two-dot chain line ofFIG. 3, the interlock apparatus according to another embodiment of the present disclosure may further include a pair of guide pins (GP1).

The pair of guide pins (GP1) are fixed to predetermined positions of the breaker body100, facing each other with a spacing distance therebetween, and are configured to allow a vertical motion of the second interlock bar200through the space therebetween.

The interlock apparatus according to the present disclosure will be explained with reference toFIGS. 5 to 7.

Referring toFIG. 5, the second interlock bar200includes an upper head portion220and a lower body portion210.

The upper head portion220is configured to contact and press the first interlock bars300, and the lower body portion210is configured to receive driving power for upward moving from the closing spring110disposed therebelow.

As shown inFIG. 5, a lower end of the lower body portion210includes a horizontally-bent portion210afor enhancing the efficiency of power transmission by widening a contact area with an upper end of the closing spring110.

As shown inFIG. 7, a contact surface of the upper head portion220of the second interlock bar200with the first interlock bars300is configured as an inclined surface221.

As shown inFIG. 7, the upper head portion220of the second interlock bar200includes a pair of operation limitation surfaces222, and a pair of inclined surfaces221.

The pair of operation limitation surfaces222are vertically formed at the upper head portion220of the second interlock bar200so as to face each other, and are configured to limit a horizontal moving distance of the first interlock bars300. That is, when the first interlock bars300are pressed by the operation limitation surfaces222, the first interlock bars300move to be spaced from each other by a width of one inclined surface221of the second interlock bar200(moved to the direction of ‘b’). On the other hand, when the first interlock bars300come in contact with the operation limitation surfaces222, the horizontal motion of the first interlock bars300is stopped.

The pair of inclined surfaces221upward extend from the operation limitation surfaces222, and are inclined so that the width of the second interlock bar200can decrease toward the upper side.

As shown inFIG. 7, each of the first interlock bars300contacting the second interlock bar200may include an inclined surface310and a curved surface310A in correspondence to the pair of operation limitation surfaces222and the pair of inclined surfaces221of the second interlock bar200.

Referring toFIGS. 5 to 7, reference numeral ‘a’ designates a moving direction of the second interlock bar200, i.e., a vertical direction, and reference numeral ‘b’ designates a moving direction of the first interlock bars300, i.e., a horizontal direction.

The operation of the interlock apparatus for a vacuum circuit breaker according to the present disclosure will be explained.

Firstly, will be explained an operation to move the breaker body100to a disconnection position (draw-out position) from a connection position (push-in position) ofFIG. 2where the breaker body100has been installed in the enclosure400so as to be connected to the terminals of the enclosure400.

If the closing spring110is in an upward-extended state to be charged with elastic energy, the second interlock bar200contacting the upper end of the closing spring110upward moves as shown inFIG. 5.

In this case, the first interlock bars300come in contact with the second interlock bar200which is upward moving, or are pressed by the second interlock bar200. As a result, the first interlock bars300move to be spaced from each other (move to the direction of ‘b’).

Referring toFIG. 6, the width (l) of the breaker body determined by the first interlock bars300having horizontally moved to be spaced from each other becomes greater than the spacing distance (d1) between the two hindering units410.

In the state that the closing spring110is charged with elastic energy, the first interlock bars300are stopped by being locked by the hindering units410. This may prevent the breaker body100from moving to the disconnection position (draw-out position).

If the closing spring110is in a downward-contracted state to discharge elastic energy, the second interlock bar200downward moves due to its weight and elastic force of the second return spring (RS2), from the up position shown inFIG. 5orFIG. 6.

As a result, the first interlock bars300do not come in contact with the second interlock bar200which is downward moving any longer, and are not pressed by the second interlock bar200any longer. Accordingly, the first interlock bars300horizontally move to be close to each other (move to the direction of ‘b’) by elastic force of the first return spring (RS1) ofFIG. 3.

The width (l) of the breaker body determined by the first interlock bars300having horizontally moved to be close to each other becomes smaller than the spacing distance (d1) between the two hindering units410.

In the state that the closing spring110discharged the elastic energy, the first interlock bars300which determine the width of the breaker body100are not stopped by the hindering units410. This may allow the breaker body100to move to the disconnection position (draw-out position).

Secondly, will be explained an operation to move the breaker body100to a connection position (push-in position) from a disconnection position (draw-out position) ofFIG. 2where the breaker body100has been drawn-out from the enclosure400.

If the closing spring110is in an upward-extended state to be charged with elastic energy, the second interlock bar200contacting the upper end of the closing spring110upward moves as shown inFIG. 5orFIG. 6.

In this case, the first interlock bars300come in contact with the second interlock bar200which is upward moving, or are pressed by the second interlock bar200. As a result, the first interlock bars300move to be spaced from each other (move to the direction of ‘b’).

Referring toFIG. 6, the width (l) of the breaker body determined by the first interlock bars300having horizontally moved to be spaced from each other becomes greater than the spacing distance (d1) between the two hindering units410.

In the state that the closing spring110is charged with elastic energy, the first interlock bars300are locked by being stopped by the hindering units410. This may prevent the breaker body100from moving to the connection position (push-in position).

If the closing spring110is in a downward-contracted state to discharge elastic energy, the second interlock bar200downward moves due to its weight and elastic force of the second return spring (RS2), from the up position shown inFIG. 5orFIG. 6.

As a result, the first interlock bars300do not come in contact with the second interlock bar200any longer which is downward moving, and are not pressed by the second interlock bar200any longer. Accordingly, the first interlock bars300horizontally move to be close to each other (move to the direction of ‘b’) by elastic force of the first return spring (RS1) ofFIG. 3.

The width (l) of the breaker body determined by the first interlock bars300having horizontally moved to be close to each other becomes smaller than the spacing distance (d1) between the two hindering units410.

In the state that the closing spring110discharged the elastic energy, the first interlock bars300which determine the width of the breaker body100are not stopped by the hindering units410. This may allow the breaker body100to move to the connection position (push-in position).

As aforementioned, in the interlock apparatus for a vacuum circuit breaker according to the present disclosure, the breaker body100may be prevented from moving to the connection position or the disconnection position in a state that the closing spring110is charged with elastic energy. This may prevent the occurrence of an accidence due to discharge of the closing spring110while the breaker body100moves.