FORM 2
THE PATENTS ACT, 197 0 (39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
DRAW-OUT CIRCUIT BREAKER
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED
AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

DESCRIPTION
Field
[0001] The present invention relates to a draw-out
circuit breaker in which a circuit breaker body is drawably
received in a drawer frame in which a terminal device is
placed.
Background
[0002] A draw-out circuit breaker including a shutter device is conventionally known. A draw-out circuit breaker including a shutter device includes a drawer frame, a terminal device placed in the drawer frame, a circuit breaker body drawable out of the drawer frame, and a shutter device attached to the front face of the terminal device.
[0003] The terminal device includes, for each phase, multiple drawer frame-side conductors connected to a power-side conductor and to a load-side conductor; and an insulation base in which the multiple drawer frame-side conductors are inserted. In addition, the circuit breaker body includes multiple circuit breaker-side conductors to be connected to the multiple drawer frame-side conductors when being received in the drawer frame. Moreover, the shutter device has functionality to cover the drawer frame-side conductors to prevent exposure of the drawer frame-side conductors as viewed from the circuit breaker body side when the circuit breaker body is drawn out of the drawer frame.
[0004] For example, Patent Literature 1 discloses a shutter device including a static shutter having openings

that allow circuit breaker-side conductors projecting from the circuit breaker body to be inserted thereinto, and a movable shutter moved by a drive mechanism to a position to cover the openings of the static shutter when the circuit breaker body is drawn out. Such draw-out circuit breaker is configured such that the insulation base provided for each phase is formed from a combination of bilaterally symmetric half bodies, and insertion of the static shutter into guide grooves provided to face each other on the two half bodies enables the static shutter to be readily attached to the insulation base.
Citation List
Patent Literature
[0005] Patent Literature 1: Japanese Patent Application
Laid-open No. H06-22418
Summary Technical Problem
[0006] However, integral formation of the insulation base provided on a per-phase basis by mold molding presents a problem in difficulty of providing, on the insulation base, the guide grooves that allow the static shutter to be inserted therein. This may prevent easy assembling or easy maintenance of the terminal unit in terms of the foregoing conventional draw-out circuit breaker.
[0007] The present invention has been made in view of the foregoing, and it is an object of the present invention to provide a draw-out circuit breaker that allows easy attachment of a static shutter to an insulation base even when the insulation base is formed by integral forming.
Solution to Problem

[0008] To solve the above problem and achieve the object described above, a draw-out circuit breaker according to an aspect of the present invention includes: a drawer frame; a terminal device; a circuit breaker body; and a shutter device. The terminal device includes a plurality of terminal units each including a plurality of drawer frame-side conductors connected to a power-side conductor and to a load-side conductor and an insulation base in which the drawer frame-side conductors are inserted, the terminal device being placed inside the drawer frame. The circuit breaker body is drawable out of the drawer frame, and includes a plurality of circuit breaker-side conductors to be connected to the drawer frame-side conductors when being received in the drawer frame. The shutter device includes a plurality of static shutters each having a plurality of openings into which the circuit breaker-side conductors are inserted when the circuit breaker body is received in the drawer frame, and a movable shutter to block the openings when the circuit breaker body is drawn out of the drawer frame. The insulation bases are arranged along a second direction perpendicular to a first direction, the first direction being a direction in which the circuit breaker body is drawn out. The insulation bases each include a pair of wall portions facing each other in the second direction. Each of the pair of wall portions includes engagement portions to engage with the static shutter. The engagement portions each include a first extension portion extending in the first direction, and a second extension portion extending in the second direction from a leading end of the first extension portion. The second extension portion of one of the pair of wall portions and the second extension portion of another one of the pair of wall portions extend in directions away from each other.

Advantageous Effects of Invention
[0009] The present invention provides an advantage in enabling easy attachment of a static shutter to an insulation base even when the insulation base is formed by integral forming.
Brief Description of Drawings
[0010] FIG. 1 is an external view of a draw-out circuit breaker according to a first embodiment of the present invention.
FIG. 2 is an external view illustrating a state in which the circuit breaker body is drawn out of the drawer frame in the draw-out circuit breaker according to the first embodiment.
FIG. 3 is a rear view illustrating arrangement, in the drawer frame, of the multiple terminal units included in the terminal device according to the first embodiment.
FIG. 4 is an exploded perspective view of the terminal unit according to the first embodiment.
FIG. 5 is a plan view illustrating an example configuration of the drawer frame-side conductors according to the first embodiment.
FIG. 6 is an external perspective view illustrating an attachment process of the shutter device to the terminal device according to the first embodiment.
FIG. 7 is an external perspective view illustrating the state after attachment of the shutter device to the terminal device according to the first embodiment.
FIG. 8 is a view illustrating an example configuration of the movable shutters according to the first embodiment.
FIG. 9 is an external perspective view illustrating an example of the shutter drive unit according to the first

embodiment.
FIG. 10 is an exploded perspective view of the shutter drive unit according to the first embodiment.
FIG. 11 is a bottom view illustrating another example of the shutter drive unit according to the first embodiment.
FIG. 12 is an external perspective view of the rod of the shutter drive unit illustrated in FIG. 11.
FIG. 13 is a plan view of the shutter drive unit having the rod and the link attached to the unit base illustrated in FIG. 11.
FIG. 14 is a plan view of the shutter drive unit having the rod and the link attached to the unit base illustrated in FIG. 11.
FIG. 15 is a cross-sectional view taken along line XV-XV illustrated in FIG. 11.
FIG. 16 is a partial cross-sectional view of the draw-out circuit breaker when the circuit breaker body is received in the drawer frame, according to the first embodiment.
FIG. 17 is a partial cross-sectional view of the draw-out circuit breaker when the circuit breaker body has been drawn out of the drawer frame, according to the first embodiment.
FIG. 18 is a front view illustrating an example of the insulation base according to the first embodiment.
FIG. 19 is an external perspective view illustrating an example of the insulation base according to the first embodiment.
FIG. 20 is a view illustrating an example configuration of the first static shutter according to the first embodiment.
FIG. 21 is a view illustrating an example configuration of the second static shutter according to the

first embodiment.
FIG. 22 is a view illustrating the state after attachment of the shutter drive units to the insulation base according to the first embodiment.
FIG. 23 is a view illustrating an attachment process of the movable shutter set to the insulation bases according to the first embodiment.
FIG. 24 is a view illustrating an attachment process of the first static shutter to the insulation bases according to the first embodiment.
FIG. 25 is a view illustrating an attachment process of the second static shutters to the insulation bases according to the first embodiment.
FIG. 26 is a front view of the terminal device having the shutter device according to the first embodiment fixed thereto.
FIG. 27 is a cross-sectional view taken along line XXII-XXII illustrated in FIG. 26.
FIG. 28 is an external perspective view illustrating another example of the insulation base according to the first embodiment.
FIG. 29 is a front view illustrating another example of the static shutter set according to the first embodiment.
FIG. 30 is a front view illustrating the state after attachment of the static shutter set illustrated in FIG. 29 to the insulation base illustrated in FIG. 28.
FIG. 31 is a front view of a terminal device according to a second embodiment.
FIG. 32 is an external perspective view illustrating an attachment process of the shutter device to the terminal device according to the second embodiment.
FIG. 33 is an external perspective view of a third static shutter according to the second embodiment.

FIG. 34 is an external perspective view of an auxiliary panel according to the second embodiment.
Description of Embodiments
[0011] A draw-out circuit breaker according to
embodiments of the present invention will be described in
detail below with reference to the drawings. Note that
these embodiments are not intended to limit the scope of
this invention.
[0012] First Embodiment.
FIG. 1 is an external view of a draw-out circuit breaker according to a first embodiment of the present invention, and FIG. 2 is an external view illustrating the state in which the circuit breaker body is drawn out of the drawer frame in the draw-out circuit breaker according to the first embodiment. Note that, for the purpose of facilitating an understanding, the drawings including FIGS.
1 and 2 illustrate a three-dimensional orthogonal
coordinate system including a Z-axis representing the
vertically upward direction as the positive direction, an
X-axis representing the forward direction of a draw-out
circuit breaker 100 according to the first embodiment as
the positive direction, and a Y-axis representing the
rightward direction of the draw-out circuit breaker 100 as
the positive direction.
[0013] As illustrated in FIG. 1, the draw-out circuit breaker 100 according to the first embodiment includes a circuit breaker body 1, which opens and closes an electrical path of a three-phase circuit; a terminal device
2 to be connected to the circuit breaker body 1; and a
drawer frame 3, in which the terminal device 2 is placed
and the circuit breaker body 1 is drawably received. As
illustrated in FIG. 2, the draw-out circuit breaker 100

further includes a draw-out rail 4, which joins together the circuit breaker body 1 and the drawer frame 3. Such draw-out rail 4 allows the circuit breaker body 1 to be drawn out of the drawer frame 3. Note that the draw-out circuit breaker 100 is housed, for example, in the enclosure of an enclosed switchboard (not illustrated) such that the circuit breaker body 1 is drawable. [0014] The circuit breaker body 1 has a known configuration for performing an opening operation and a closing operation of an electrical path of a three-phase circuit. The opening operation is an operation of breaking the electrical path of each of phase R, phase S, and phase T of the three-phase circuit. The closing operation is an operation of closing the electrical path of each of phase R, phase S, and phase T of the three-phase circuit. [0015] The circuit breaker body 1 includes a housing 10, which houses fixed contacts, movable contacts, an opening-closing mechanism, and a trip mechanism (each not illustrated); and circuit breaker-side conductors 11-1, 11-2, 11-3, 12-1, 12-2, and 12-3 projecting rearward from the housing 10. The fixed contacts and the movable contacts are provided on a per-phase basis. Note that the circuit breaker-side conductors 11-1, 11-2, and 11-3 may each be referred to as circuit breaker-side conductor 11 without distinction therebetween, and the circuit breaker-side conductors 12-1, 12-2, and 12-3 may each be referred to as circuit breaker-side conductor 12 without distinction therebetween.
[0016] The housing 10 has a front portion 10a having thereon operation buttons (not illustrated). Operation of such operation buttons triggers a closing operation that brings the movable contact into contact with the fixed contact on a per-phase basis, and an opening operation that

separates the movable contact from the fixed contact on a per-phase basis. Bringing the movable contact into contact with the fixed contact on a per-phase basis causes the corresponding electrical path of the three-phase circuit to be closed, which brings the circuit breaker body 1 into a conduction state. In addition, separation of the movable contact from the fixed contact on a per-phase basis causes the corresponding electrical path of the three-phase circuit to be opened, which brings the circuit breaker body
1 into a non-conduction state. Moreover, the trip
mechanism provided in the housing 10 is configured to, upon
occurrence of an overcurrent condition in the three-phase
circuit, automatically separate the movable contact from
the fixed contact on a per-phase basis to open the
corresponding electrical path of the three-phase circuit.
[0017] The circuit breaker-side conductors 11 are
conductors connected to the fixed contacts provided in the
housing 10 and electrically connected to power-side
conductors (not illustrated) via the terminal device 2.
The circuit breaker-side conductors 12 are conductors connected to the movable contacts provided in the housing 10 and electrically connected to load-side conductors (not illustrated) via the terminal device 2. The circuit breaker-side conductors 11-1 and 12-1 are conductors that form the electrical path of phase R. The circuit breaker-side conductors 11-2 and 12-2 are conductors that form the electrical path of phase S. The circuit breaker-side conductors 11-3 and 12-3 are conductors that form the electrical path of phase T. Note that the example illustrated in FIG. 2 illustrates the circuit breaker-side conductors 11 as being provided above the circuit breaker-side conductors 12, but the circuit breaker-side conductors
11 may be provided under the circuit breaker-side

conductors 12.
[0018] The terminal device 2 includes multiple insulation bases 21, and drawer frame-side conductors 22-1, 22-2, 22-3, 23-1, 23-2, and 23-3 housed in these multiple insulation bases 21 with respective rear portions thereof projecting out. The drawer frame-side conductors 22-1 and 23-1 are conductors that form the electrical path of phase R. The drawer frame-side conductors 22-2 and 23-2 are conductors that form the electrical path of phase S. The drawer frame-side conductors 22-3 and 23-3 are conductors that form the electrical path of phase T. Note that the drawer frame-side conductors 22-1, 22-2, and 22-3 are each referred to as drawer frame-side conductor 22 when no distinction is made between them. The drawer frame-side conductors 23-1, 23-2, and 23-3 are each referred to as drawer frame-side conductor 23 when no distinction is made between them.
[0019] The drawer frame-side conductors 22 each have one end portion projecting from the insulation base 21 and connected to the corresponding one of the power-side conductors (not illustrated), and each have another end portion to be connected to the corresponding one of the circuit breaker-side conductors 11 when the circuit breaker body 1 is received in the drawer frame 3. In addition, the drawer frame-side conductors 23 each have one end portion projecting from the insulation base 21 and connected to the corresponding one of the load-side conductors (not illustrated), and each have another end portion to be connected to the corresponding one of the circuit breaker-side conductors 12 when the circuit breaker body 1 is received in the drawer frame 3. Note that a power-side conductor is a conductor for connecting together a power supply device and the draw-out circuit breaker 100. In

addition, a load-side conductor is a conductor for connecting together a load supplied with electrical power from the power supply device and the draw-out circuit breaker 100. The load is, for example, an electrical device that operates by electrical power from the power supply device. The configuration of the terminal device 2 will be described later in detail.
[0020] The drawer frame 3 includes left and right sideboards 31 and 32. As illustrated in FIG. 1, the circuit breaker body 1 is drawably received in the drawer frame 3, which is defined by a region sandwiched between the left and right sideboards 31 and 32. In addition, the terminal device 2 is detachably placed in the drawer frame 3. In the example illustrated in FIG. 1, the circuit breaker body 1 is received in the drawer frame 3 under a condition in which the front portion 10a of the circuit breaker body 1 is exposed; and the terminal device 2 is placed in the drawer frame 3 under a condition in which the drawer frame-side conductors 22 and 23 project rearward. Note that the drawer frame 3 is not limited to one having the configuration illustrated in FIGS. 1 and 2, and the receiving position of the circuit breaker body 1 in the drawer frame 3 and the placement position of the terminal device 2 in the drawer frame 3 are not limited to the respective positions of the example illustrated in FIGS. 1 and 2 .
[0021] The draw-out rail 4 is a draw-out rail that joins together the circuit breaker body 1 and the drawer frame 3 to allow the circuit breaker body 1 to be drawable out of the drawer frame 3. The draw-out rail 4 includes multiple rail members 41 and 42 joined together to allow the draw-out rail 4 to have a length that is variable in the anterior-posterior direction. Note that it is sufficient

for the draw-out rail 4 to be configured to join together the circuit breaker body 1 and the drawer frame 3 to allow the circuit breaker body 1 to be drawable out of the drawer frame 3, and the configuration thereof is not limited to what is illustrated in FIG. 2. In addition, the draw-out circuit breaker 100 may include, in place of the draw-out rail 4, one or more members that join together the circuit breaker body 1 and the drawer frame 3 to allow the circuit breaker body 1 to be drawable out of the drawer frame 3.
[0022] The circuit breaker body 1 includes, for example, a drawing handle and a draw-out mechanism (each not illustrated). Engagement of the drawing handle with the draw-out mechanism and then rotation of the drawing handle allows the draw-out rail 4 to extend and retract in the anterior-posterior direction by means of the draw-out mechanism. Extension of the draw-out rail 4 in the anterior-posterior direction causes the circuit breaker body 1 to be drawn out of the drawer frame 3. In addition, retraction of the draw-out rail 4 in the anterior-posterior direction causes the circuit breaker body 1 to be received in the drawer frame 3, thereby causing the circuit breaker-side conductors 11 and 12 of the circuit breaker body 1 and the drawer frame-side conductors 22 and 23 of the terminal device 2 to be connected to each other.
[0023] A specific configuration of the terminal device 2 will next be described. FIG. 3 is a rear view illustrating arrangement, in the drawer frame, of the multiple terminal units included in the terminal device according to the first embodiment. As illustrated in FIG. 3, the terminal device 2 includes three terminal units 20-1, 20-2, and 20-3.
[0024] The example illustrated in FIG. 3 illustrates how the terminal units 20-1, 20-2, and 20-3 are placed in the drawer frame 3. The bidirectional arrows illustrated in

FIG. 3 indicate the moving directions of the terminal units 20-1 and 20-2. The terminal units 20-1, 20-2, and 20-3 can be placed in the drawer frame 3 by being moved from an upper portion to a lower portion of the drawer frame 3, and can be removed from the drawer frame 3 by being moved toward the upper portion.
[0025] The terminal units 20-1, 20-2, and 20-3 each have a lower end portion to be inserted in an opening (not illustrated) of a holding plate 33 included in the drawer frame 3 to thus be held by the holding plate 33. In addition, the terminal units 20-1, 20-2, and 20-3 each have an upper end portion, as illustrated in FIG. 2, to be inserted in an opening (not illustrated) of a holding plate 34 included in the drawer frame 3 to thus be held by the holding plate 34. This secures the terminal device 2 to the drawer frame 3. The holding plates 33 and 34 are secured to the sideboards 31 and 32, and removal of the holding plate 33 from the sideboards 31 and 32 allows the terminal units 20-1, 20-2, and 20-3 to be removed from the drawer frame 3. As described above, the terminal device 2 is detachably placed in the drawer frame 3.
[0026] The terminal unit 20-1 includes the drawer frame-side conductors 22-1 and 23-1. In addition, the terminal unit 20-2 includes the drawer frame-side conductors 22-2 and 23-2. The terminal unit 20-3 includes the drawer frame-side conductors 22-3 and 23-3. The terminal units 20-1, 20-2, and 20-3 have the same configuration as one another. The terminal units 20-1, 20-2, and 20-3 are each referred to as terminal unit 20 when no distinction is made between them.
[0027] FIG. 4 is an exploded perspective view of the terminal unit according to the first embodiment, and FIG. 5 is a plan view illustrating an example configuration of the

drawer frame-side conductors according to the first embodiment. As illustrated in FIG. 4, the terminal unit 20 includes the insulation base 21 and the drawer frame-side conductors 22 and 23. The insulation base 21 includes a terminal accommodation portion 215, in which the drawer frame-side conductor 22 is inserted; a terminal accommodation portion 216, in which the drawer frame-side conductor 23 is inserted; and two unit accommodation portions 217, in which two shutter drive units 53 (described later) are respectively inserted. [0028] The drawer frame-side conductor 22 includes a terminal conductor 221, a relay terminal conductor 222, and a connector 223. In addition, the drawer frame-side conductor 23 includes a terminal conductor 231, a relay terminal conductor 232, and a connector 233. Due to the drawer frame-side conductors 22 and 23 having the same configuration as each other, a configuration of the drawer frame-side conductor 22 will be described by way of example. [0029] The terminal conductor 221 of the drawer frame-side conductor 22 has a bottom portion 221a lying along the Z-Y plane, i.e., a first vertical plane; and a terminal portion 221b extending rearward from the bottom portion 221a and positioned in parallel to the X-Y plane, i.e., the horizontal plane. The terminal portion 221b of the terminal conductor 221 is connected with a power-side conductor (not illustrated). Note that the terminal conductor 231 has a terminal portion connected with a load-side conductor (not illustrated). The example illustrated in FIG. 4 illustrates the bottom portion 221a as having a square shape whose four sides have the same length as viewed from the front, and forming a rectangular solid. In addition, the terminal portion 221b is formed to extend perpendicularly to the bottom portion 221a and rearward

from an intermediate portion of a region sandwiched between the sides vertically facing each other of the bottom portion 221a. The bottom portion 221a has a bottom surface that is a flat surface. Note that the terminal portion 221b is formed in a T-shape as viewed from the side, but the shape thereof is not limited to the shape illustrated in FIG. 4.
[0030] The relay terminal conductor 222 has a bottom portion 222a lying along the Z-Y plane, i.e., the first vertical plane; and a leading end portion 222b extending forward from the bottom portion 222a along the X-Z plane, i.e., a second vertical plane perpendicular to the first vertical plane, and formed in a Y-shape as viewed from the top. The relay terminal conductor 222 is inserted in the terminal accommodation portion 215, and the bottom portion 222a of the relay terminal conductor 222 is secured by multiple screws 25. Note that the screws 25 are screwed into the relay terminal conductor 222 through screw holes 219 provided in the insulation base 21.
[0031] As illustrated in FIG. 5, the bottom portion 222a of the relay terminal conductor 222 is joined to the bottom portion 221a of the terminal conductor 221 by means of multiple bolts 24. This causes the relay terminal conductor 222 and the terminal conductor 221 to be electrically connected to each other. Note that the example illustrated in FIGS. 4 and 5 illustrates the relay terminal conductor 222 and the terminal conductor 221 as being secured to each other using the four bolts 24, but the number of the bolts 24 is not limited to four. In addition, the relay terminal conductor 222 and the terminal conductor 221 may also be secured to each other using a fastening device other than the bolts 24.
[0032] As illustrated in FIG. 5, the connector 223 of

the drawer frame-side conductor 22 is connected to the relay terminal conductor 222. This connector 223 is connected to the circuit breaker-side conductor 11 of the circuit breaker body 1 when the circuit breaker body 1 is received in the drawer frame 3. The connector 223 includes a groove portion 223a to engage with the relay terminal conductor 222, and a groove portion 223b to engage with the circuit breaker-side conductor 11.
[0033] The connector 223 and the relay terminal conductor 222 are connected to each other through insertion of the leading end portion 222b of the relay terminal conductor 222 into the groove portion 223a of the connector 223. The groove portion 223a and the leading end portion 222b are each formed from a resilient member. This causes the outer surface of the leading end portion 222b and the inner wall surface of the groove portion 223a to press against each other upon engagement of the leading end portion 222b with the groove portion 223a. This can thus provide firm engagement between the leading end portion 222b and the groove portion 223a, and can accordingly prevent separation of the relay terminal conductor 222 and the connector 223 upon pulling of the circuit breaker-side conductor 11 from the drawer frame-side conductor 22. Thus, the engagement between the leading end portion 222b and the groove portion 223a also serves as a stopper. [0034] In addition, the connector 223 and the circuit breaker-side conductor 11 are connected to each other through insertion of the leading end portion of the circuit breaker-side conductor 11 into the groove portion 223b of the connector 223. The connector 223 can swing upon insertion of the leading end portion of the circuit breaker-side conductor 11 into the groove portion 223b of the connector 223. The connector 223 swings about the

engagement portion between the leading end portion 222b and the groove portion 223a. Note that the connector 223 may also be configured not to swing. In addition, the relay terminal conductor 222 and the terminal conductor 221 may be formed by integral molding, and the terminal conductor 221, the relay terminal conductor 222, and the connector 223 may be formed by integral molding.
[0035] A shutter device 5 to be attached to the terminal unit 20 will next be described. FIG. 6 is an external perspective view illustrating an attachment process of the shutter device to the terminal device according to the first embodiment, and FIG. 7 is an external perspective view illustrating the state after attachment of the shutter device to the terminal device according to the first embodiment.
[0036] As illustrated in FIGS. 6 and 7, the shutter device 5 includes a static shutter set 51 for covering the front face of the terminal device 2; a movable shutter set 52 placed between the static shutter set 51 and the terminal device 2; and two shutter drive units 53. The static shutter set 51 includes a first static shutter 511 and two second static shutters 512. The movable shutter set 52 includes two movable shutters 521. An upper movable shutter 521 of the two movable shutters 521 is a movable shutter for the power supply side, and a lower movable shutter 521 is a movable shutter for the load side. [0037] The shutter drive units 53 are inserted in the unit accommodation portions 217 formed in the insulation base 21 illustrated in FIG. 4. After insertion of the shutter drive units 53 into the unit accommodation portions 217, the two movable shutters 521 are attached to the insulation bases 21 of the respective terminal units 20-1, 20-2, and 20-3. Then, the static shutter set 51 is

attached to the insulation bases 21 of the respective terminal units 20-1, 20-2, and 20-3. The first static shutter 511 is placed at a position facing the terminal unit 20-2. One of the two second static shutters 512 is placed at a position facing the terminal unit 20-1, and the other thereof is placed at a position facing the terminal unit 20-3.
[0038] First, a configuration of the movable shutters 521, a configuration of the shutter drive units 53, and a relationship between the movable shutters 521 and the shutter drive units 53 will be described. FIG. 8 is a view illustrating an example configuration of the movable shutters according to the first embodiment.
[0039] As illustrated in FIG. 8, the movable shutter 521 includes blocking plate portions 521a, 521b, and 521c; a joining portion 521d that joins together one end portions of the respective blocking plate portions 521a, 521b, and 521c; a joining portion 521e that joins together another end portions of the respective blocking plate portions 521a, 521b, and 521c; and a projecting portion 521f projecting outward from the joining portion 521e. The projecting portion 521f has an opening 521g formed therein. [0040] The movable shutters 521 are slidably attached to the insulation bases 21. As illustrated in FIG. 6, each of the insulation bases 21 has sliding surfaces 211a and 212a formed thereon. The movable shutters 521 are each slidably attached to the sliding surface 211a or to the sliding surface 212a. The movable shutters 521 can each slide on the sliding surface 211a or on the sliding surface 212a in the left-right direction to selectively move between a blocking position and an opening position. [0041] The blocking position is a position to block openings 511a and 512a or openings 511b and 512b of the

static shutter set 51 by the blocking plate portions 521a, 521b, and 521c. In addition, the opening position is a position not to block the opening 511a or 512a or the opening 511b or 512b by the blocking plate portions 521a, 521b, and 521c.
[0042] FIG. 9 is an external perspective view illustrating an example of the shutter drive unit according to the first embodiment, and FIG. 10 is an exploded perspective view of the shutter drive unit according to the first embodiment. As illustrated in FIGS. 9 and 10, the shutter drive units 53 each include a housing unit 530; a compression spring 533 having one end fixed to the housing unit 530; and a rod 534 having a base end biased to another end of the compression spring 533. The shutter drive units 53 also each include a coil spring 535 rotatably held on the housing unit 530 and having one end anchored to the housing unit 530; and a link 536 biased by another end of the coil spring 535 to be engaged with the corresponding movable shutter 521.
[0043] The housing unit 530 includes a unit base 531, on which a sliding groove 531a allowing the rod 534 to slide thereon and a shaft unit 531b having a cylindrical shape to rotatably support the link 536 are formed; and a unit cover 532 attached from thereabove to the unit base 531. The unit cover 532 has multiple projecting portions 532a and 532b formed thereon, projecting in the right or left direction. The compression spring 533, the coil spring 535, the link 536, and a portion of the rod 534 are arranged in a space defined by the unit base 531 and the unit cover 532.
[0044] The rod 534 has an extension portion 534a extending in the anterior-posterior direction; a base end portion 534b continuous with the rear end of the extension portion 534a and fixed to the another end of the

compression spring 533; an engagement portion 534c projecting rearward from the base end portion 534b along the compression spring 533 and having an arc shaped face facing the link 536 in the left-right direction; and a contact portion 534d to come into contact with the circuit breaker body 1 and be pressed by the circuit breaker body 1. In the state illustrated in FIGS. 9 and 10, the rod 534 has the base end portion 534b being secured to the housing unit 530 while the base end portion 534b is biased forward by the compression spring 533. When the circuit breaker body 1 is received in the drawer frame 3, the contact portion 534d of the rod 534 is pressed rearward by the circuit breaker body 1 against push-back force of the compression spring 533, thereby causing the rod 534 to move rearward. [0045] The link 536 is formed in an L-shape, and has an angled portion rotatably supported by the shaft unit 531b of the unit base 531. The link 536 has an opening 536a, into which the shaft unit 531b is inserted; a first arm portion 536b biased by the another end of the coil spring 535 thereby biasing forward the engagement portion 534c of the rod 534; and a second arm portion 536c having a leading end 536d that projects out of the opening 530a of the housing unit 530 and is to be inserted in the opening 521g of the movable shutter 521.
[0046] Rearward movement of the rod 534 caused by the circuit breaker body 1 causes the leading end of the first arm portion 536b to be pushed rearward by the engagement portion 534c of the rod 534. Rearward movement of the engagement portion 534c causes the first arm portion 536b to rotate clockwise as viewed from the top. This causes the second arm portion 536c to rotate clockwise about the shaft unit 531b as viewed from the top, thereby causing the leading end 536d of the second arm portion 536c to move

from left to right. The leading end 536d of the second arm portion 536c is engaged with the opening 521g of the movable shutter 521. Thus, a movement of the leading end 536d to the right causes the movable shutter 521 to move to the opening position.
[0047] The shutter drive units 53 are not each limited to one having the configuration illustrated in FIGS. 9 and 10, but may also be configured to hold the rod when the movable shutters 521 are each at a releasing position. FIG.
11 is a bottom view illustrating another example of the shutter drive unit according to the first embodiment. FIG.
12 is an external perspective view of the rod of the shutter drive unit illustrated in FIG. 11. FIGS. 13 and 14 are each a plan view of the shutter drive unit having the rod and the link attached to the unit base illustrated in FIG. 11. FIG. 15 is a cross-sectional view taken along line XV-XV illustrated in FIG. 11.
[0048] The shutter drive unit 53 illustrated in FIG. 11 is configured such that the unit base 531 and the rod 534 each have a shape partly different from the shape in the shutter drive unit 53 illustrated in FIG. 9. The rod 534 has, as illustrated in FIG. 12, a protrusion 534e protruding downward from a bottom portion of the base end portion 534b. In addition, the unit base 531 has, as illustrated in FIGS. 11 and 13, a guide groove 531c, which guides the movement of the protrusion 534e provided on the rod 534 in the anterior-posterior direction; and a recess 531d continuous at the left thereof with the guide groove 531c. The recess 531d has a sloped portion 531e, which guides the protrusion 534e to the guide groove 531c upon a rearward movement of the rod 534.
[0049] When the circuit breaker body 1 has been drawn out of the drawer frame 3, the extension portion 534a of

the rod 534 is drawn out forward due to bias force of the compression spring 533 (not illustrated) as illustrated in FIG. 13. Upon movement of the circuit breaker body 1 toward the drawer frame 3 from the state illustrated in FIG. 13, the protrusion 534e moves rearward by the guide of the guide groove 531c, thereby bringing the rod 534 to the state illustrated in FIG. 14. This causes the movable shutter 521 to move from a blocking position to the releasing position.
[0050] In addition, when the rod 534 is moved rearward from the state in which the circuit breaker body 1 has been drawn out of the drawer frame 3 to move the protrusion 534e to a position to face the recess 531d and then the rod 534 is rotated, the protrusion 534e enters the recess 531d. Removal of force of pressing the rod 534 rearward in this state causes the protrusion 534e to be latched by the recess 531d. The movable shutter 521 is moved from the blocking position to the releasing position before the protrusion 534e moves to the position to face the recess 531d, and this can hold the movable shutter 521 in the releasing position.
[0051] Accordingly, the movable shutter 521 on the power side and the movable shutter 521 on the load side can be individually or simultaneously kept at the releasing position during service and maintenance, thereby enabling the circuit on the power side and the circuit on the load side in the terminal device 2 to be individually or simultaneously inspected. Note that the base end portion 534b of the rod 534 is formed in an arc shape having an axial center that is the extension portion 534a. This configuration causes the base end portion 534b of the rod 534 to be kept at a substantially unchanged distance from the first arm portion 536b even after rotation of the rod

534. This can thus avoid a situation in which too large a force is exerted from the rod 534 to the link 536, which would cause buckling of the link 536.
[0052] In addition, a movement of the circuit breaker body 1 toward the drawer frame 3 when the protrusion 534e is latched by the recess 531d causes the rod 534 to move rearward by the circuit breaker body 1. In this operation, the protrusion 534e moved into the recess 531d rotates during the rearward movement with sliding on the sloped portion 531e of the recess 531d, thereby causing the rotated rod 534 to return to the original position before the circuit breaker body 1 is received in the drawer frame 3. This causes the protrusion 534e and the recess 531d to be disengaged from each other. Thus, thereafter, when the circuit breaker body 1 is drawn out of the drawer frame 3, the rod 534 is moved by the compression spring 533. In this operation, the protrusion 534e having returned into the guide groove 531c moves along the guide groove 531c, and the protrusion 534e moves forward beyond the recess 531d. This prevents the movable shutter 521 from staying at the releasing position.
[0053] FIG. 16 is a partial cross-sectional view of the draw-out circuit breaker when the circuit breaker body is received in the drawer frame, according to the first embodiment, and FIG. 17 is a partial cross-sectional view of the draw-out circuit breaker when the circuit breaker body has been drawn out of the drawer frame, according to the first embodiment. Note that FIGS. 16 and 17 omit the drawer frame 3 and the draw-out rail 4. [0054] As illustrated in FIG. 10, when the circuit breaker body 1 is received in the drawer frame 3, the circuit breaker-side conductor 11-1 is inserted in the terminal accommodation portion 215 of the terminal device 2

via the opening 512a of the second static shutter 512. In the terminal accommodation portion 215, the circuit breaker-side conductor 11-1 is connected to the connector 223 of the drawer frame-side conductor 22-1. Similarly, the circuit breaker-side conductor 11-2 is inserted in the terminal accommodation portion 215 of the terminal device 2 via the opening 511a of the first static shutter 511, and is connected to the connector 223 of the drawer frame-side conductor 22-2. The circuit breaker-side conductor 11-3 is inserted in the terminal accommodation portion 215 of the terminal device 2 via the opening 512a of the second static shutter 512, and is connected to the connector 223 of the drawer frame-side conductor 22-3. In a state when the circuit breaker body 1 is received in the drawer frame 3, the rod 534 has been pushed in the shutter drive unit 53. [0055] As illustrated in FIG. 17, the draw-out circuit breaker 100 is configured such that when the circuit breaker body 1 is drawn out of the drawer frame 3 in the forward direction from the state illustrated in FIG. 16, the rod 534 that has been pushed in the corresponding unit accommodation portion 217 of the circuit breaker body 1 is pushed forward by extension force of the compression spring 533 illustrated in FIG. 10. This causes the leading end 536d of the second arm portion 536c of the shutter drive unit 53 to move the movable shutter 521 to the blocking position after the circuit breaker-side conductors 11-1, 11-2, and 11-3 pass through the openings 511a and 512a. This causes the openings 511a and 512a to be blocked by the blocking plate portions 521a, 521b, and 521c. [0056] Next, a configuration of the insulation base 21, a configuration of the static shutter set 51, and a relationship between the insulation base 21 and the static shutter set 51 will be described. A configuration of the

insulation base 21 will first be described specifically. FIG. 18 is a front view illustrating an example of the insulation base according to the first embodiment, and FIG. 19 is an external perspective view illustrating an example of the insulation base according to the first embodiment. [0057] As illustrated in FIGS. 18 and 19, the insulation base 21 is formed in a bilaterally symmetric shape. Such insulation base 21 includes a top wall portion, i.e., a wall portion 211; a bottom wall portion, i.e., a wall portion 212; a left sidewall portion, i.e., a wall portion 213; and a right sidewall portion, i.e., a wall portion 214. The terminal accommodation portions 215 and 216 and the two unit accommodation portions 217 are formed in the space surrounded by the wall portions 211, 212, 213, and 214. The two unit accommodation portions 217 are each a space for accommodating the shutter drive unit 53 described above, and are each formed in a portion between the terminal accommodation portion 215 and the terminal accommodation portion 216.
[0058] The wall portion 211 has a sliding surface 211a, which allows the movable shutter 521 to slide thereon, and a guide portion 211b provided in front of the sliding surface 211a and projecting downward. The guide portion 211b prevents the movable shutter 521 from dropping off the sliding surface 211a.
[0059] The wall portion 212 has a sliding surface 212a, which allows the movable shutter 521 to slide thereon, and a guide portion 212b provided in front of the sliding surface 212a and projecting upward. The guide portion 212b prevents the movable shutter 521 from dropping off the sliding surface 212a.
[0060] The wall portions 213 and 214 have sliding grooves 213a and 214a, and stopper portions 213b and 214b.

The multiple projecting portions 532a of the shutter drive unit 53 illustrated in FIG. 10 slide along the sliding grooves 213a and 214a when the shutter drive unit 53 is inserted in the corresponding one of the unit accommodation portions 217. Abutment of the multiple projecting portions 532b of the shutter drive unit 53 illustrated in FIG. 10 onto the stopper portions 213b and 214b restricts the rearward movement of the shutter drive unit 53.
[0061] The wall portions 213 and 214 also have sliding surfaces 213c and 214c. By sliding of the two movable shutters 521 on the sliding surfaces 211a and 212a and on the sliding surfaces 213c and 214c described above, the two movable shutters 521 can slide thereon in the left-right direction.
[0062] In addition, the wall portions 213 and 214 have first projecting portions 213d and 214d, second projecting portions 213e and 214e, and engagement portions 213f and 214f each formed to project forward beyond the sliding surfaces 213c and 214c. The second projecting portions 213e and 214e project forward beyond the first projecting portions 213d and 214d, and the engagement portions 213f and 214f project forward beyond the second projecting portions 213e and 214e. The first projecting portions 213d and 214d each have a front face serving as a first shutter-attached surface to be in contact with the rear face of the first static shutter 511, and the second projecting portions 213e and 214e each have a front face serving as a second shutter-attached surface to be in contact with the rear face of the corresponding second static shutter 512. The front faces of the first projecting portions 213d and 214d and the sliding surfaces 213c and 214c are positioned with a gap in the anterior-posterior direction greater than the thickness of the movable shutter 521 in the anterior-

posterior direction.
[0063] The engagement portions 213f are each formed in an L-shape, and each have a first extension portion 213fl extending forward, and a second extension portion 213f2 extending from the leading end of the first extension portion 213fl to the left. The engagement portions 214f each have a first extension portion 214fl extending forward, and a second extension portion 214f2 extending from the leading end of the first extension portion 214fl to the right.
[0064] As described above, the engagement portions 213f and 214f have leading ends extending in the left-right direction and outward from the circuit breaker body 1, that is, leading ends extending in directions away from each other. This configuration enables the engagement portions 213f and 214f to be easily positioned at positions facing no other portions in the anterior-posterior direction, and thus allows the insulation bases 21 to be integrally formed by mold molding.
[0065] FIG. 20 is a view illustrating an example configuration of the first static shutter according to the first embodiment. As illustrated in FIG. 20, the first static shutter 511 has the opening 511a, into which the circuit breaker-side conductor 11 is inserted; the opening 511b, into which the circuit breaker-side conductor 12 is inserted; and openings 511c, in each of which the rod 534 is inserted. The first static shutter 511 also has openings 511d, in each of which the leading end 536d of the second arm portion 536c is inserted; multiple openings 511e and 511h, in each of which the second projecting portions 213e are inserted; multiple openings 511f and 511i, in each of which the engagement portions 213f are inserted; and two recesses 511g, which engage with the multiple guide

portions 211b. Note that the multiple recesses 511g are formed to allow the multiple guide portions 211b and 212b to fit thereinto, but may be formed in any form that allows engagement therebetween. The form is thus not limited to the form illustrated in FIG. 20.
[0066] FIG. 21 is a view illustrating an example configuration of the second static shutter according to the first embodiment. As illustrated in FIG. 21, the second static shutters 512 each have the opening 512a, into which the circuit breaker-side conductor 11 is inserted; the opening 512b, into which the circuit breaker-side conductor 12 is inserted; multiple engagement portions 512c and 512d having a protruding shape, projecting downward, and each engaging with the engagement portion(s) 213f and/or 214f; and multiple recesses 512e, which engage with the multiple guide portions 211b and 212b. Note that the multiple recesses 512e may be formed in any form that allows engagement with the multiple guide portions 211b and 212b. The form is thus not limited to the form illustrated in FIG. 21.
[0067] The second static shutters 512 also each have multiple cutouts 512f, 512g, and 512h, in each of which at least one of the first extension portions 213fl and 214fl is inserted. The cutouts 512f are cut out to the left, and the cutouts 512g and 512h are cut out to the right. The cutouts 512f are provided adjacent to the engagement portions 512c described above, and the cutout 512g is provided adjacent to 512d described above. The cutout 512h is provided at a position below the cutout 512g.
[0068] An attachment process of the static shutter set 51 and the movable shutter set 52 to the insulation bases 21 will next be described. FIG. 22 is a view illustrating the state after attachment of the shutter drive units to

the insulation base according to the first embodiment. FIG. 23 is a view illustrating an attachment process of the movable shutter set to the insulation bases according to the first embodiment. FIG. 24 is a view illustrating an attachment process of the first static shutter to the insulation bases according to the first embodiment. FIG. 25 is a view illustrating an attachment process of the second static shutters to the insulation bases according to the first embodiment. FIG. 26 is a front view of the terminal device having the shutter device according to the first embodiment fixed thereto. FIG. 27 is a cross-sectional view taken along line XXII-XXII illustrated in FIG. 26. Note that, for convenience of illustration, FIGS. 22, 23, 24, 25, 26, and 27 do not illustrate the drawer frame-side conductors 22 or the drawer frame-side conductors 23 in the insulation bases 21.
[0069] First, as illustrated in FIG. 22, the three terminal units 20-1, 20-2, and 20-3 are placed adjacent to each other in the left-right direction. Next, the two shutter drive units 53 are inserted into the two unit accommodation portions 217 formed in the insulation base 21 of the central terminal unit 20-2 of the three terminal units 20-1, 20-2, and 20-3. Note that the two shutter drive units 53 are respectively inserted into the two unit accommodation portions 217 in a laterally and vertically inverted relationship to each other.
[0070] Then, as illustrated in FIG. 23, the two movable shutters 521 are attached to the terminal units 20-1, 20-2, and 20-3. Specifically, one of the two movable shutters 521 is slidably placed on the upper sliding surfaces 211a, 213c, and 214c, and the opening 521g is inserted in the leading end 536d of the second arm portion 536c of the upper one of the shutter drive units 53. In addition, the

other one of the movable shutters 521 is slidably placed on the lower sliding surfaces 212a, 213c, and 214c, and the opening 521g is inserted in the leading end 536d of the second arm portion 536c of the lower one of the shutter drive units 53.
[0071] Note that placement of one of the movable shutters 521 between the sliding surface 211a and the guide portion 211b prevents that movable shutter 521 from dropping off the terminal unit 20. In addition, placement of the other one of the movable shutters 521 between the sliding surface 212a and the guide portion 212b prevents that movable shutter 521 from dropping off the terminal unit 20.
[0072] Then, as illustrated in FIG. 24, the first static shutter 511 is attached to the insulation base 21 of the terminal unit 20-2. In the state illustrated in FIG. 24, the guide portions 211b and 212b of the insulation base 21 of the terminal unit 20-2 are fit into the upper and the lower recesses 511g of the first static shutter 511. [0073] Then, the second projecting portions 213e of the terminal unit 20-1 and the second projecting portions 214e of the terminal unit 20-2 are fit into the openings 511h of the first static shutter 511. The second projecting portions 213e of the terminal unit 20-2 and the second projecting portions 214e of the terminal unit 20-3 are fit into the openings 511e of the first static shutter 511. The engagement portions 213f of the terminal unit 20-1 and the engagement portions 214f of the terminal unit 20-2 are fit into the openings 511i of the first static shutter 511. The engagement portions 213f of the terminal unit 20-2 and the engagement portions 214f of the terminal unit 20-3 are fit into the openings 511f of the first static shutter 511. [0074] As described above, the first static shutter 511

is fit into the terminal units 20-1, 20-2, and 20-3. This allows, upon attachment of the first static shutter 511 to the terminal unit 20-2, the three terminal units 20-1, 20-2, and 20-3 to be joined together by the first static shutter 511. Note that, in the state illustrated in FIG. 24, the rods 534 described above of the two respective shutter drive units 53 are projecting out of the openings 511b described above of the first static shutter 511. [0075] Then, as illustrated in FIGS. 25 and 27, the second static shutters 512 are attached to the terminal units 20-1 and 20-3 after attachment of the first static shutter 511. In the state illustrated in FIGS. 25 and 27, the engagement portions 512c of each of the second static shutters 512 each engage with the engagement portions 213f and 214f of the two respective terminal units 20 adjacent to each other. The engagement portion 512d of the second static shutter 512 engages with one of the engagement portions 213f and 214f of the terminal unit 20. [0076] Specifically, the engagement portions 512c of the second static shutter 512 are each inserted between the engagement portions 213f and 214f of the two respective terminal units 20 adjacent to each other and the front face of the first static shutter 511. Thus, the engagement portions 512c of the second static shutter 512 are each interposed between the rear faces of the second extension portions 213f2 and 214f2 of the respective engagement portions 213f and 214f and the front face of the first static shutter 511.
[0077] In addition, the engagement portion 512d of the second static shutter 512 is inserted in the space formed between the plane including the front face of the second projecting portion 213e and the rear face of the second extension portion 213f2 of the engagement portion 213f, or

in the space formed between the plane including the front face of the second projecting portion 214e and the rear face of the second extension portion 214f2 of the engagement portion 214f. The engagement portion 512d of the second static shutter 512 thus engages with one of the engagement portions 213f and 214f.
[0078] Moreover, at least one of the first extension portions 213fl and 214fl is inserted in each of the cutouts 512f and 512g of the second static shutters 512, and the cutouts 512f and 512g thus each engage with at least one of the engagement portions 213f and 214f. The cutouts 512f are each formed in a region including areas to the left and right of, and an area under, the corresponding one of the engagement portions 512c. The first extension portions 213fl and 214fl are inserted in the area under each of the engagement portions 512c of the cutouts 512f, and at least one of the first extension portions 213fl and 214fl is inserted in the cutout 512g. Then, moving the second static shutter 512 downward causes at least one of the engagement portions 213f and 214f to engage with the cutouts 512f and 512g and the engagement portions 512c and 512d to engage with the engagement portions 213f and 214f when at least one of the engagement portions 213f and 214f has been inserted in each of the cutouts 512f and 512g. Similarly, at least one of the first extension portions 213fl and 214fl is inserted in the cutout 512h of the second static shutter 512, which thus engages with at least one of the engagement portions 213f and 214f. [0079] The first static shutter 511 has a plate thickness substantially equal to the distance between the front faces of the first projecting portions 213d and 214d and the front faces of the second projecting portions 213e and 214e. This causes the rear face of the second static

shutter 512 to be pressed against the front face of the first static shutter 511 and against the front faces of the second projecting portions 213e, and moreover, the engagement portion 512d of the second static shutter 512 to be pressed against the rear face of the second extension portion 213f2 of the engagement portion 213f or against the rear face of the second extension portion 214f2 of the engagement portion 214f.
[0080] As described above, the two second static shutters 512 are attached to the terminal units 20 having the first static shutter 511 already attached thereto such that a part of each of the two second static shutters 512 overlaps a part of the first static shutter 511. This places the first static shutter 511 between the terminal unit 20 and the second static shutters 512, and thereby prevents the first static shutter 511 from dropping off the terminal unit 20.
[0081] In the example described above, the insulation base 21 has the second projecting portions 213e and 214e in the circuit breaker body 1, but the circuit breaker body 1 may be configured to have none of the second projecting portions 213e and 214e on the insulation base 21. In this case, the static shutter set 51 will have a partially different configuration. FIG. 28 is an external perspective view illustrating another example of the insulation base according to the first embodiment. FIG. 29 is a front view illustrating another example of the static shutter set according to the first embodiment. FIG. 30 is a front view illustrating the state after attachment of the static shutter set illustrated in FIG. 29 to the insulation base illustrated in FIG. 28.
[0082] The insulation base 21 illustrated in FIG. 28 does not have the second projecting portion 213e or 214e

illustrated in FIG. 18. In addition, the plane including the front faces of the first projecting portions 213d and 214d and the rear faces of the second extension portions 213f2 and 214f2 of the engagement portions 213f and 214f are apart from each other with a gap substantially equal to the plate thickness of each of the first static shutter 511 and the second static shutters 512.
[0083] The first static shutter 511 illustrated in FIG. 29 has engagement portions 511k having a protruding shape and projecting downward in place of the openings 511e, 511f, 511h, and 511i illustrated in FIG. 20. In addition, the second static shutters 512 illustrated in FIG. 29 each have engagement portions 512i having a protruding shape and projecting downward in place of the engagement portions 512c illustrated in FIG. 21. The engagement portions 511k and 512i are provided adjacent to the cutouts in which the first extension portions 213fl and 214fl of the engagement portions 213f and 214f are inserted. The engagement portions 512i each have a width less than the width of the engagement portions 512c. In addition, the first static shutter 511 and the second static shutters 512 each have a width substantially equal to the width of the insulation bases 21. Note that the term "width" as used herein means the length in the left-right direction. [0084] As illustrated in FIG. 30, the engagement portions 213f and 214f provided on the insulation base 21 of the terminal unit 20-2 engage with the multiple engagement portions 511k of the first static shutter 511 illustrated in FIG. 29. In addition, the engagement portions 213f provided on the insulation base 21 of the terminal unit 20-1 engage with the engagement portions 512i of the corresponding second static shutter 512 illustrated in FIG. 29. Moreover, the engagement portions 214f

provided on the insulation base 21 of the terminal unit 20-3 engage with the engagement portions 512i of the corresponding second static shutter 512 illustrated in FIG. 29. As described above, the circuit breaker body 1 may be configured to have none of the second projecting portions 213e and 214e on the insulation base 21. Note that the circuit breaker body 1 may have only one terminal unit 20 to perform an opening operation and a closing operation of the electrical path of a single-phase circuit. [0085] As described above, the draw-out circuit breaker 100 according to the first embodiment includes the circuit breaker body 1, the terminal device 2, the drawer frame 3, and the shutter device 5. The terminal device 2 includes the multiple terminal units 20, each including the multiple drawer frame-side conductors 22 and 23 respectively connected to a power-side conductor and to a load-side conductor and the insulation base 21, in which the multiple drawer frame-side conductors 22 and 23 are inserted. The terminal device 2 is placed in the drawer frame 3. The circuit breaker body 1 includes the multiple circuit breaker-side conductors 11 and 12 to be connected to the multiple drawer frame-side conductors 22 and 23 when the circuit breaker body 1 has been received in the drawer frame 3, and is drawable out of the drawer frame 3. The shutter device 5 includes the first static shutter 511, the second static shutters 512, and the movable shutters 521. The first static shutter 511 includes the multiple openings 511a and 511b, into which the multiple circuit breaker-side conductors 11 and 12 are inserted when the circuit breaker body 1 is received in the drawer frame 3. The second static shutters 512 each include the multiple openings 512a and 512b, into which the multiple circuit breaker-side conductors 11 and 12 are inserted when the circuit breaker

body 1 is received in the drawer frame 3. The movable shutters 521 block the multiple openings 511a and 512a or the multiple openings 511b and 512b when the circuit breaker body 1 is drawn out of the drawer frame 3. The multiple insulation bases 21 are arranged along the direction perpendicular to the direction in which the circuit breaker body 1 is drawn out, i.e., the draw-out direction. The multiple insulation bases 21 each have a pair of wall portions 213 and 214 facing each other in the direction perpendicular to the draw-out direction. The pair of wall portions 213 and 214 has the engagement portions 213f and 214f, which engage with at least one of the first static shutter 511 and the second static shutters 512. The engagement portions 213f and 214f respectively have the first extension portions 213fl and 214fl extending in the draw-out direction; and the second extension portions 213f2 and 214f2 extending from the leading ends of the corresponding first extension portions 213fl and 214fl in the direction perpendicular to the draw-out direction. The second extension portion 213f2 of one of the pair of wall portions 213 and 214 and the second extension portion 214f2 of the other one thereof extend in directions away from each other. The engagement portions 213f and 214f have leading ends extending in the directions opposite to the directions toward each other. This enables the engagement portions 213f and 214f to be easily positioned at positions facing no other portions in the anterior-posterior direction, and thus allows the insulation bases 21 to be integrally formed by mold molding. [0086] The first static shutter 511 also includes the openings 511f and 511i, into which the first extension portions 213fl and 214fl are inserted. The openings 511f and 511i are examples of first opening. The second static

shutters 512 also each include the cutouts 512f and 512g, into which at least one the first extension portions 213fl and 214fl is inserted; and the engagement portions 512c and 512d, which project downward and engage with the second extension portions 213f2 and 214f2 of the engagement portions 213f and 214f in a state in which the openings 511f and 511i of the first static shutter 511 have received the first extension portions 213fl and 214fl inserted therein. Thus, the second static shutters 512 are attached to the terminal device 2 having the first static shutter 511 already attached thereto such that a part of each of the second static shutters 512 overlaps a part of the first static shutter 511. This places the first static shutter 511 between the terminal device 2 and the second static shutters 512, and thereby prevents the first static shutter 511 from dropping off the terminal device 2. The engagement portions 512c and 512d are examples of shutter-side engagement portion.
[0087] In addition, the pair of wall portions 213 and 214 has the second projecting portions 213e and 214e extending in the draw-out direction. The first static shutter 511 has the openings 511e, into which the second projecting portions 213e and 214e are inserted. The openings 511e are examples of second opening. The second static shutters 512 each abut the front faces of the second projecting portions 213e and 214e at the surface opposite the surface facing the circuit breaker body 1. This allows the second static shutters 512 to be held such that the second projecting portions 213e and 214e engage with the first static shutter 511 and the second static shutters 512 are pressed against the front faces of the second projecting portions 213e and 214e. The first static shutter 511 and the second static shutters 512 can thus be

more stably attached to the terminal device 2.
[0088] Moreover, the openings 511e receive the second projecting portions 213e of the two insulation bases 21 adjacent to each other of the multiple insulation bases 21. This enables the first static shutter 511 to be attached across multiple ones of the insulation bases 21, and can thus prevent, for example, relative displacement between the multiple insulation bases 21.
[0089] Furthermore, the first static shutter 511 and the second static shutters 512 are attached to the terminal device 2 to partly overlap each other. This enables the first static shutter 511 and the second static shutters 512 to be more stably attached to the terminal device 2.
[0090] Furthermore, the shutter device 5 includes the shutter drive units 53 that drive the movable shutters 521 in conjunction with drawing of the circuit breaker body 1 out of the drawer frame 3. The shutter drive units 53 are placed between the multiple drawer frame-side conductors 22 and 23, inside one insulation base 21 of the multiple insulation bases 21. Placement of the shutter drive units 53 between the multiple drawer frame-side conductors 22 and 23 can prevent an increase in the width of the insulation bases 21 and in the width of the draw-out circuit breaker 100. In addition, the shutter drive units 53 are placed at the vertical center in the insulation base 21. This enables the movable shutters 521 to be moved with higher accuracy than when the shutter drive units 53 would be placed above the drawer frame-side conductor 22 and under the drawer frame-side conductor 23, even if the circuit breaker body 1 is received askew in the drawer frame 3. Moreover, if, for example, the shutter drive units 53 are placed in the terminal units 20-1 and 20-3, which means that the shutter drive units 53 are placed separately in

the left-right direction, insertion of the circuit breaker body 1 askew in the left-right direction would cause one of the shutter drive units 53 to be driven earlier and the other one of the shutter drive units 53 to be driven later. This might thus cause the movable shutter 521 driven later to impinge against the circuit breaker-side conductor 11 or against the circuit breaker-side conductor 12. Thus, placement of the shutter drive units 53 in the central insulation base 21 of the multiple insulation bases 21 enables the movable shutters 521 to be moved with higher accuracy even if the draw-out circuit breaker 100 is received askew in the left-right direction in the drawer frame 3.
[0091] In addition, the shutter drive units 53 each include the rod 534 biased in the draw-out direction, and the link 536. The link 536 rotates in conjunction with the movement of the rod 534 in the direction opposite to the draw-out direction to move the corresponding movable shutter 521 from the blocking position for blocking the multiple openings 511a, 511b, 512a, and 512b to the releasing position for exposing the multiple openings 511a, 511b, 512a, and 512b. This enables the shutter drive units 53 to move the movable shutters 521 with a relatively small force.
[0092] In addition, the shutter drive units 53 each include the unit base 531, which rotatably holds the link 536 and receives the rod 534 inserted in conjunction with the movement of the rod 534 in the direction opposite to the draw-out direction. The unit base 531 is capable of holding the rod 534 under a condition in which the corresponding movable shutter 521 is at the releasing position. Thus, by moving the movable shutter(s) 521 in the releasing position during service and maintenance, the

power-side circuit and the load-side circuit in the terminal device 2 can be individually or simultaneously inspected.
[0093] Moreover, the rod 534 has the protrusion 534e projecting downward, i.e., in the direction perpendicular to the draw-out direction. The shutter drive units 53 each include the guide groove 531c, which guides the protrusion 534e; and the recess 531d continuous with the guide groove 531c in the direction perpendicular to the draw-out direction to latch the protrusion 534e. This allows the movable shutters 521 to be easily kept at the releasing position.
[0094] Furthermore, the recess 531d has the sloped portion 531e, which allows the protrusion 534e to enter the guide groove 531c in conjunction with the movement of the rod 534 in the direction opposite to the draw-out direction. This enables the protrusion 534e to return back into the guide groove 531c by reception of the circuit breaker body 1 in the drawer frame 3, and can thus easily avoid the situation in which the movable shutter 521 is kept at the releasing position.
[0095] Second Embodiment.
A draw-out circuit breaker according to a second embodiment differs from the draw-out circuit breaker 100 according to the first embodiment in the number of the terminal units 20 and in the configuration of the static shutter set. In the following description, like reference characters designate elements having functionality similar to the functionality of the first embodiment. A description of such elements will be omitted, and differences from the draw-out circuit breaker 100 of the first embodiment will be primarily described.
[0096] FIG. 31 is a front view of a terminal device

according to the second embodiment, and FIG. 32 is an external perspective view illustrating an attachment process of the shutter device to the terminal device according to the second embodiment. As illustrated in FIGS. 31 and 32, a terminal device 2A according to the second embodiment includes four terminal units 20-1, 20-2, 20-3, and 20-4 configured the same as one another. In addition, a shutter device 5A includes a static shutter set 51A, a movable shutter set 52A, and the two shutter drive units 53.
[0097] The movable shutter set 52A includes two movable shutters 521A. The movable shutters 521A each have four blocking plate portions and thus differ from the movable shutters 521 each having the three blocking plate portions 521a, 521b, and 521c.
[0098] The static shutter set 51A includes the first static shutter 511, the second static shutter 512, a third static shutter 513, and an auxiliary panel 514. The first static shutter 511 is attached to the terminal unit 20-2. The second static shutter 512 is attached to the terminal unit 20-1. The third static shutter 513 is attached to the two terminal units 20-3 and 20-4. In addition, the auxiliary panel 514 is attached to the wall portion 213 of the terminal unit 20-3 and to the wall portion 214 of the terminal unit 20-4.
[0099] FIG. 33 is an external perspective view of the third static shutter according to the second embodiment, and FIG. 34 is an external perspective view of the auxiliary panel according to the second embodiment. As illustrated in FIG. 33, the third static shutter 513 has openings 513a, into which the circuit breaker-side conductors 11 are inserted; openings 513b, into which the circuit breaker-side conductors 12 are inserted; multiple engagement portions 513c, 513d, and 513i each having a

protruding shape, projecting downward, and engaging with at least one of the engagement portions 213f and 214f; and multiple recesses 513e, which engage with the multiple guide portions 211b and 212b.
[0100] The third static shutter 513 also has multiple cutouts 513f, 513g, and 513h, in each of which at least one of the first extension portions 213fl and 214fl is inserted; and openings 513j, in each of which the first extension portions 213fl and 214fl are inserted. The cutouts 513f, 513g, and 513h are respectively configured the same as the cutouts 512f, 512g, and 512h described above. The openings 513j are provided adjacent to the engagement portions 513i. The third static shutter 513 is attached such that the first extension portions 213fl and 214fl are inserted in the area under the engagement portion 513i of each of the openings 513j, and the third static shutter 513 is then moved downward. This causes the engagement portions 213f and 214f to engage with the openings 513j and with the engagement portions 513i in the state in which the engagement portions 213f and 214f are inserted in the openings 513j.
[0101] The engagement portions 513c, 513d, and 513i of the third static shutter 513 function similarly to the engagement portions 512c and 512d of the second static shutter 512. In addition, the recesses 513e of the third static shutter 513 function similarly to the recesses 512e of the second static shutter 512. Thus, the third static shutter 513 is attached to the terminal units 20-2, 20-3, and 20-4 having the first static shutter 511 already attached such that a part of the third static shutter 513 overlaps a part of the first static shutter 511.
[0102] As illustrated in FIG. 34, the auxiliary panel 514 has multiple openings 514a and multiple openings 514b.

The second projecting portion 213e of the terminal unit 20-3 and the second projecting portion 214e of the terminal unit 20-4 are inserted into the multiple openings 514a. In addition, the engagement portion 213f of the terminal unit 20-3 and the engagement portion 213f of the terminal unit 20-4 are inserted into the multiple openings 514b. The auxiliary panel 514 is placed between the third static shutter 513 and the terminal units 20-3 and 20-4. Thus, the rear face of the third static shutter 513 is in contact with the front faces of the second projecting portions 213e and with the front face of the auxiliary panel 514, thereby allowing the third static shutter 513 to be stably attached to the terminal device 2A. Note that the shutter device 5A may also be configured not to include the auxiliary panel 514.
[0103] As described above, also in a case in which the number of poles is increased to four or more, the static shutter set 51A can be attached to the terminal device 2A on a principle similar to the draw-out circuit breaker 100 according to the first embodiment.
[0104] The configurations described in the foregoing embodiments are merely examples of various aspects of the present invention. These configurations may be combined with a known other technology, and moreover, a part of such configurations may be omitted and/or modified without departing from the spirit of the present invention.
Reference Signs List
[0105] 1 circuit breaker body; 2, 2A terminal device; 3 drawer frame; 4 draw-out rail; 5, 5A shutter device; 10 housing; 10a front portion; 11, 11-1, 11-2, 11-3, 12, 12-1, 12-2, 12-3 circuit breaker-side conductor; 20, 20-1, 20-2, 20-3, 20-4 terminal unit; 21 insulation base; 22,

22-1, 22-2, 22-3, 23, 23-1, 23-2, 23-3 drawer frame-side conductor; 24 bolt; 25 screw; 31, 32 sideboard; 33, 34 holding plate; 41, 42 rail member; 51, 51A static shutter set; 52, 52A movable shutter set; 53 shutter drive unit; 100 draw-out circuit breaker; 211, 212, 213, 214 wall portion; 211a, 212a, 213c, 214c sliding surface; 211b, 212b guide portion; 213a, 214a sliding groove; 213b, 214b stopper portion; 213d, 214d first projecting portion; 213e, 214e second projecting portion; 213f, 214f, 512c, 512d, 511k, 512i, 513c, 513d, 513i, 534c engagement portion; 213fl, 214fl first extension portion; 213f2, 214f2 second extension portion; 215, 216 terminal accommodation portion; 217 unit accommodation portion; 219 screw hole; 221, 231 terminal conductor; 221a, 222a bottom portion; 221b terminal portion; 222, 232 relay terminal conductor; 222b leading end portion; 223, 233 connector; 223a, 223b groove portion; 511 first static shutter; 511a, 511b, 511c, 511d, 511e, 511f, 511h, 511i, 512a, 512b, 513a, 513b, 513j, 514a, 514b, 521g, 536a opening; 511g, 512e, 513e, 531d recess; 512 second static shutter; 512f, 512g, 512h, 513f, 513g, 513h cutout; 513 third static shutter; 514 auxiliary panel; 521, 521A movable shutter; 521a, 521b, 521c blocking plate portion; 521d, 521e joining portion; 521f, 532a, 532b projecting portion; 530 housing unit; 531 unit base; 531a sliding groove; 531b shaft unit; 531c guide groove; 531e sloped portion; 532 unit cover; 533 compression spring; 534 rod; 534a extension portion; 534b base end portion; 534d contact portion; 534e protrusion; 535 coil spring; 536 link; 536b first arm portion; 536c second arm portion; 536d leading end.

We Claim :
1. A draw-out circuit breaker comprising:
a drawer frame;
a terminal device including a plurality of terminal units each including a plurality of drawer frame-side conductors connected to a power-side conductor and to a load-side conductor and an insulation base in which the drawer frame-side conductors are inserted, the terminal device being placed inside the drawer frame;
a circuit breaker body drawable out of the drawer frame, and including a plurality of circuit breaker-side conductors to be connected to the drawer frame-side conductors when being received in the drawer frame; and
a shutter device including a plurality of static shutters each having a plurality of openings into which the circuit breaker-side conductors are inserted when the circuit breaker body is received in the drawer frame, and a movable shutter to block the openings when the circuit breaker body is drawn out of the drawer frame, wherein
the insulation bases are arranged along a second direction perpendicular to a first direction, the first direction being a direction in which the circuit breaker body is drawn out,
the insulation bases each include
a pair of wall portions facing each other in the second direction,
each of the pair of wall portions includes
engagement portions to engage with the static shutter,
the engagement portions each include
a first extension portion extending in the first direction, and a second extension portion extending in the second direction from a leading end of the first extension portion, and

the second extension portion of one of the pair of wall portions and the second extension portion of another one of the pair of wall portions extend in directions away from each other.
2. The draw-out circuit breaker according to claim 1,
wherein
the static shutters include a first static shutter and a second static shutter,
the first static shutter has
a first opening into which the first extension portion of the engagement portion is inserted,
the second static shutter includes
a cutout into which the first extension portion of the engagement portion is inserted, and
a shutter-side engagement portion that projects in a third direction perpendicular to both of the first direction and the second direction to engage with the second extension portion of the engagement portion in which the first extension portion is inserted into the first opening of the first static shutter.
3. The draw-out circuit breaker according to claim 2,
wherein
each of the pair of wall portions includes a projecting portion projecting in the first direction,
the first static shutter has
a second opening into which the projecting portion of the insulation base is inserted, and
the second static shutter abuts the projecting portion at a surface opposite a surface facing the circuit breaker body.

4. The draw-out circuit breaker according to claim 3,
wherein
the projecting portions of two insulation bases adjacent to each other of the insulation bases are inserted into the second opening.
5. The draw-out circuit breaker according to any one of
claims 1 to 4, wherein
the shutter device includes
a shutter drive unit to move the movable shutter in conjunction with drawing of the circuit breaker body out of the drawer frame, and
the shutter drive unit is placed
between the drawer frame-side conductors inside one insulation base of the insulation bases.
6. The draw-out circuit breaker according to claim 5,
wherein
the shutter drive unit includes a rod biased in the first direction, and a link to rotate in conjunction with a movement of the rod in a direction opposite to the first direction to move the movable shutter from a blocking position for blocking the openings to a releasing position for exposing the openings.
7. The draw-out circuit breaker according to claim 6,
wherein
the shutter drive unit includes
a unit base to rotatably hold the link and to receive the rod inserted in conjunction with a movement of the rod in the direction opposite to the first direction, and
the unit base is capable of holding the rod under a

condition in which the movable shutter is at the releasing position.
8. The draw-out circuit breaker according to claim 7,
wherein
the rod includes
a protrusion projecting in a direction perpendicular
to the first direction, and
the shutter drive unit includes
a guide groove to guide the protrusion, and
a recess continuous with the guide groove in a
direction perpendicular to the first direction to latch the
protrusion.
9. The draw-out circuit breaker according to claim 8,
wherein
the recess includes
a sloped portion to allow the protrusion to enter the guide groove in conjunction with a movement of the rod in the direction opposite to the first direction.