FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
& THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
CIRCUIT BREAKER;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANIZED AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

Technical Field
[0001]
The present invention relates to a circuit breaker such as a breaker for wiring or a ground-fault circuit interrupter, and more specifically, to the configuration of a tripping mechanism for such a circuit breaker.
Background Art
[0002]
In a circuit breaker having a known fast-in mechanism for rapid connection between contacts regardless of the speed of operation of a manual handle, a main spring provides the tripping force of a lever. The tripping force, that is, the associated force of switching can be ensured regardless cf the ON or OFF state of the mechanism. In contrast, a circuit breaker having a slow-in mechanism has no such a main spring, so that the tripping force of a lever is provided by the upward force of a push plate instead. When the breaker is in an OFF state, the push plate is locked by a stopper, and the tripping force cannot be provided typically and the tripping operation is not possible in the OFF state.

[0003]
In recent years, however, the tripping operation in the OFF state has been increasingly needed, for example in checking the operation of an alarm contact. An example of proposed structures of the circuit breaker capable of tripping operation even in the OFF state includes a torsion spring formed to press an abutting piece for a latch plate against a free end of a bimetal such that it presses the latch plate with a large force when a handle is in an OFF state and presses the latch plate with a small force when the handle is in an ON state (see the seventh row in a lower right column of page 3 to the second row in a lower right column of page 4 in PTL 1)
[0004]
Although the circuit breaker in the related art allows the tripping operation even in the OFF state, the following problem arises when that configuration is used for the tripping operation in the OFF state without any change. Specifically, the torsion spring for applying a moment to the abutting plate for the latch plate continues to apply the moment to the abutting plate even in the ON state, so that the tripping load for the abutting plate is disadvantageously increased. The increased tripping load prevents a reduction in size of a tripping apparatus for releasing the abutting plate and limits the tolerance in tripping force of the tripping apparatus to cause the problem of unstable tripping operation.

[0005]
In general, the configuration needs to be assembled simply in order to employ automatic assembly. Since the frame of the mechanism described above is formed of a combination of two bent metal plates on which each of components is held, the torsion spring is typically formed inside the metal plates, If the end of the spring is attempted to be put after the combination of the plates of the frame, that work is difficult since the spring is located inside and less accessible. In some cases, expensive equipment is required such as a robot which moves precisely. If the spring is located outside the frame, the spring can be put more easily, but an additional operation of preventing the removal of the spring is necessary.
Citation List Patent Literature
[0006]
PTL 1: JP-A-58-131625
Summary of Invention Technical Problem
[0007]
The present invention has been made in view of the above problems, and it is an object thereof to provide a circuit breaker capable of a tripping operation in an OFF state as

described above which is simply provided with no need of additional components, is adapted for automatic assembly, and achieves a reduced size and stabilized operation.
Solution to Problem
[0008]
A circuit breaker according to the present invention including a frame fixed to a housing, a manual handle pivotally fitted to the frame, a fixed contact conductor provided with a fixed contact, a movable contact conductor provided with a movable contact coming into and out of contact with the fixed contact, an opening spring urging the movable contact conductor in a direction open and separate from the fixed contact conductor, and an open/close mechanism portion performing ON/OFF operation of the fixed contact and the movable contact through pivot operation of the manual handle and detecting an overcurrent or a short-circuit current to perform trip operation, characterized by including a push plate moved upward and downward relative to the housing in engagement with the movable contact conductor, a roller engaging with an upper portion of the push plate, a link pivotally fitting the roller to a handle hole in the manual handle with a link pin, a torsion spring having a longer foot and a shorter foot and held on a spring lock axis corresponding to a pivot axis of the manual handle, and an engaging protruding portion provided on the

frame near the spring lock axis and locking the crossed longer foot and shorter foot of the torsion spring, and
characterized in that the longer foot has a length to engage with the link pin, the shorter foot has a length not to engage with the link pin, and the longer foot of the torsion spring is locked to the engaging protruding portion during the pivot operation of the manual handle.
Advantageous Effects of Invention
[0009]
According to the present invention, the tripping load can be reduced without requiring additional components, the tripping portion can be reduced in size, and both the cost and size of the circuit breaker can be reduced.
Brief Description of Drawings
[0010]
[Fig. 1] Fig. 1 is a sectional side view of a circuit breaker in an ON state in Embodiment 1 of the present invention.
[Fig. 2] Fig. 2 is an enlarged perspective view showing components of a disassembled open/close mechanism portion of the circuit breaker shown in Fig. 1.
[Fig. 3] Fig. 3 is an enlarged side view of a relay portion in Embodiment 1.
[Fig. 4] Fig. 4 is a sectional side view of the circuit

breaker in an OFF state in Embodiment 1.
[Fig, 5] Fig. 5 is a sectional side view of the circuit breaker in a tripping state in Embodiment 1.
[Fig. 6] Fig. 6 is a perspective view showing the state in which an OFF tripping spring is temporarily placed on a frame flat-shape plate in Embodiment 1.
[Fig. 7] Fig. 7 is a diagram showing the state in which a tripping button switch is mounted in Embodiment 1.
Description of Embodiment
[00111 Embodiment 1
Fig. 1 to Fig* 8 show a circuit breaker according to Embodiment 1 of the present invention. In Fig. 1 and Fig. 2* a circuit breaker 100 is formed of a housing 1 made of an insulating material, a manual handle 10 capable of being operated externally, a fixed contact conductor 2 provided with a fixed contact 4, a movable contact conductor 5 provided with a movable contact 6 coming into and out of contact with the fixed contact 4, and an open/close mechanism portion 50 performing ON/OFF operation of the fixed contact 4 and the movable contact 6, and other components, all of which are included in the housing 1.
[0012]
The open/close mechanism portion 50 includes a push plate

7 made of an insulating material and moving upward and downward on the sheet along a groove, not shown, in the housing 1 in engagement with the movable contact conductor 5, a roller 11 engaging with the push plate 7 from above, a link 13 pivotally fitting the roller 11 to a handle hole 10a in the manual handle 10 with a link pin 9, and an opening spring 21 urging the movable contact conductor 5 against the fixed contact conductor 2 in an open direction, The link 13 is pivotally fixed by a pin, not shown, and the manual handle 10 is operated to push down the push plate 7 through the roller 11. The movable contact conductor 5 is formed to overcome the force of the opening spring 21 to achieve closing operation with the fixed contact conductor 2. When the circuit breaker 100 is in an OFF state, the movable contact conductor 5 is open and separate from the fixed contact conductor 2 by the urging force of the opening spring 21.
[0013]
As shown in Fig. 2, a frame 12 has a rectangular tubular shape provided by combining a U-shaped plate 12a and a flat plate 12b by swaging and is fixed to the housing 1. A lever 16 is formed by striking out the flat plate 12b of the frame 12 and is pivotally fitted on a pivotal axis 15 and a recessed portion 18 of the U-shaped plate 12a. The lever 16 engages with a trip bar 8 on the left side face on the sheet at the end away from the pivotal axis and engages with the roller 11

on the right side face opposite thereto. The roller 11 is urged toward the lever 16 by a push plate inclined portion 7a provided on an upper portion of the push plate 7, and moves upward and downward along the right side face of the lever 16 by the operation of the handle 10*
[0014]
The frame 12 also supports the open/close mechanism portion 50 performing the open/close operation* A lower end face of the frame 12 is placed on the moving track of the push plate 7 and serves as a stopper for the push plate 7 to limit the upper position thereof. The flat plate 12b of the frame 12 has a spring lock axis 12c serving as a hole formed at the position corresponding to the handle pivot axis 10b and formed by burring for inserting the handle pivot axis 10b and for holding and fixing an OFF trip spring 14 serving as a torsion spring. An engaging protruding portion 12d formed by bending a portion of the frame 12 into an L shape is formed near {immediately below in the drawings) the spring lock axis 12c, to which a longer foot 14a and a shorter foot 14b of the OFF trip spring 14 crossed are locked and fixed (see Fig. 6) * The longer foot 14a is long enough to engage with the link pin 9 inserted through the handle hole 10a of the manual handle 10, and the shorter foot 14b has a length not to engage with the link pin 9. The trip bar 8 has a T shape with its central portion pivotally supported on the frame 12 with a pin 8c and is urged

counterclockwise in the drawings by another torsion spring, not shown.
[0015]
As shown in Fig. 3, a relay portion 17 is formed of a coil 17a through which an overcurrent or a short-circuit current flows, an iron core 17b excited by the coil 17a, an armature 17c absorbed.by the iron core 17b, and a press portion 17d associated with the armature 17c . to hit a pressure-receiving portion 8a of the trip bar 8 to release the engagement between the lever 16 and the trip bar 8.
[0016]
The operation will hereinafter be described.
First, description is made of the operation of the circuit breaker 100 from OFF to ON with reference to Fig. 1 and Fig. 4. When the manual handle 10 is pushed in a direction indicated by an arrow A in the OFF state shown in Fig, 4, the manual handle 10 is turned about the handle axis 10b to move the link 13 coupled to the handle hole 10a through the link pin 9 in a direction indicated by an arrow B. The roller 11 coupled to the link 13 abuts on the lever 16 to push the push plate 7 downward along the side face of the lever 16. The longer foot 14a of the OFF trip spring 14 in engagement with the link pin 9 is locked to the engaging protruding portion 12d of the frame at a certain time during the operation of the manual handle 10, so that the link pin 9 or the manual handle 10 does

not receive any force from the OFF trip spring 14. Although the longer foot 14a of the OFF trip spring 14 engages with the link pin 9, the longer foot 14a may be engaged with a protrusion formed on the manual handle 10 instead of the link pin 9.
[0017]
When the push plate 7 is moved downward, the movable contact conductor 5 in engagement with the push plate 7 is moved in a direction in which it comes into contact with the fixed contact conductor 2 under a reaction force from the opening spring 21. In this manner, the movable contact 6 comes into contact with the fixed contact 4 to bring the movable contact conductor 5 in an ON state shown in Fig. 1, thereby completing the operation from OFF to ON. Since the link pin 9 is located slightly on the left of the line connecting the handle axis 10b with the roller 11 on the sheet of Fig. 1 to apply the upward force to the link pin 9 from the roller 11 through the link 13, the manual handle 10 is stopped at the ON position.
[0018]
Next, description is made of the operation from ON to OFF with reference to Fig. 1 and Fig. 4 . When the manual handle 10 is pushed in a direction indicated by an arrow C in Fig. 1, the handle axis 10b, the link pin 9, and the roller 11 are arranged in a straight line. In the process, the movable contact conductor 5 is slightly pushed down. When the link pin 9 is moved to the right of the straight line in Fig. 1,

the push plate 7 under the reaction force of the opening spring 21 pushes the roller 11 and the link 13 upward, which starts to act to further turn the manual handle 10 in the C direction.
[0019]
During the turn, the link pin 9 is put on the spring longer foot 14a to apply a load in a direction in which the rotation of the link pin 9 is prevented. However, the turning moment of the link pin 9 is greater than the spring moment of the OFF trip spring 14, so that the manual handle 10 is turned in the C direction without any interruption. The link pin 9 coupled to the handle hole 10a is also moved to the right (D direction) in Fig. 1, and the roller 11 coupled to the link 13 is moved upward in the sheet of Fig. 1. As a result, the push plate 7 and the movable contact conductor 5 return to the OFF position through the operation opposite to the operation performed from OFF to ON, and the movable contact 6 and the fixed contact 4 are open and separated from each other to enter the OFF state shown in Fig. 4*
[0020]
Next, description is made of the tripping operation when an overcurrent flows through the circuit breaker 100 with reference to Fig. 1, Fig. 3, and Fig. 5.
In Fig. 3, when an overcurrent flows through the coil 17a, a magnetic force occurs in the iron core 17b which is then attracted in a direction indicated by an arrow E. This

increases the force of attracting the armature 17c to rotate the armature 17c counterclockwise, thereby causing the press portion 17d to hit the trip bar 8 in a direction indicated by an arrow F. As shown in Fig. 1, the trip bar 8 is pivoted clockwise in a direction indicated by an arrow G to release the engagement between an engaging portion 8b of the trip bar 8 and an engaging portion 16a of the lever 16. This causes the lever 16 to pivot in a direction indicated by an arrow H, and the opening spring 21 pushes the push plate 7 and the movable contact conductor 5 upward to separate the movable contact 6 from the fixed contact 4, thereby entering the tripping state shown in Fig. 5,-.
[0021]
Next, description is made of the tripping operation with a tripping button switch in the OFF state, for example when the operation of an alarm contact is checked, with reference to Fig. 7.
As shown in Fig. 7, a trip button switch 20 is placed on an upper portion of the armature 17c and is fixed to the housing 1 such that it can be moved upward and downward. For checking the tripping operation, the trip button 20 is pressed downward as indicated by an arrow shown into contact with an upper face portion of the armature 17c. This causes the armature 17c to be turned counterclockwise on the sheet. Similarly to the tripping operation performed when the

overcurrent flows as described above, the press portion 17d pivots the pressure-receiving portion 8a of the trip bar 8 to release the engagement between the engaging portion 8b of the trip bar 8 and the engaging portion 16a of the lever 16 to complete the tripping operation*
[0022]
To electrically output the tripping state of the circuit breaker 100, an accessary apparatus including a microswitch may be used within the circuit breaker* It is well known that the microswitch is switched by using the pivot of the lever 16 (in a direction indicated by an arrow K in Fig. 4) . Since the moment of the OFF trip spring 14 is set such that the pivot force of the lever 16 is greater than the switching force of the microswitch, the tripping operation or the switching force for the microswitch contained in the accessary apparatus can be provided even in the OFF state in which the push plate 7 is locked to a lower end portion of the frame 12 and the push-up force of the opening spring 21 is not available*
[0023]
Next, description is made of the operation for returning from the tripping state to the OFF state with reference to Fig. 4 and Fig. 5. In Fig. 5, when the manual handle 10 is turned in an L direction, the link 13 and the roller 11 also follows in an M direction, and the roller 11 is drawn from the gap between the lever 16 and the push plate 7. After the roller 11 is drawn,

a lever pivot protrusion 10c of the manual handle 10 comes into contact with the handle engaging face 16c of the lever 16 to turn the lever 16 in an N direction. Thus, the lever 16, which locked trip bar 8, is removed. The trip bar 8 is pivoted counterclockwise by a torsion spring, not shown on the sheet, to return the engagement between the engaging face 8b of the trip bar 8 and an end 16a of the lever 16, thereby entering the OFF state shown in Fig. 4,
[0024]
Fig. 6 is a perspective view showing tha state in which the OFF trip spring 14 is temporarily assembled on the frame flat plate 12b. The coil portion of the OFF trip spring 14 is mounted on the spring lock axis 12c formed by burring of the flat plate 12b of the frame 12, and the longer foot 14a and the shorter foot 14b of the OFF trip spring 14 are locked to the engaging protruding portion 12d of the flame flat plate 12b in the state in which they exert a torsion moment, The engaging protruding portion 12d of the flame flat plate 12b forms a recessed portion corresponding to the latch positions of the longer foot 14a and the shorter foot 14d of the OFF trip spring 14 as shown in Fig. 6 to prevent the removal of the spring foot and the removal of the coil portion.
[0025]
According to the present embodiment, since the OFF trip spring 14 is locked to the engaging protruding portion 12d

provided for the frame 12 in the ON state and the link pin 9 is not urged, the force applied to the lever 16 in the ON state can be eliminated to significantly reduce the tripping load for the lever 16, Since this can simplify the configuration of the tripping apparatus, the circuit breaker can be reduced in size.
[0026]
In addition, since the engaging protruding portion 12d provided for the frame 12 has the recessed portion corresponding to the latch positions of the longer foot 14a and the shorter foot 14b of the OFF trip spring 14, the OFF trip spring 14 to be incorporated into the frame can be supplied together with the frame at the time of supply of the frame by temporarily fixing the OFF trip spring 14 to the frame 12, resulting in facilitated assembly which eliminates the need to put the spring after the assembly of the mechanism. This can also reduce the investment cost in performing the automatic assembly.
Although the above embodiment has been described with the example in which the OFF trip spring 14 is held and fixed to the spring lock axis 12c formed by the burring of the flat plate 12d of the frame 12, the axis 12c formed by the burring can be replaced with the handle axis 10b.
Reference Signs List

[0027] 1 Housing, 2 Fixed Contact Conductor, 4 Fixed Contact, 5 Movable Contact Conductor, 6 Movable Contact, 7 Push Plate, 7a Push Plate Inclined Face 8 Trip Bar, 8a Pressure-Receiving Portion of Trip Bar, 8b Engaging Portion of Trip Bar with Lever, 9 Link Pin, 10 Manual Handle, 10a Handle Hole, 10b Handle Axis, 10c Lever Pivot Protrusion, 11 Roller, 12 Frame, 12a Frame U-shaped Plate, 12b Frame Flat Plate, 12c Spring Lock Axis, 12d Engaging Protruding Portion, 13 Link, 14 OFF Trip Spring, 14a Longer Foot, 14b Shorter Foot, 16 Lever, 16a End of Lever Engaging with Trip Bar, 16c handle Engaging Face of Lever, 17 Relay Portion, 17a Coil, 17b Iron Core, 17c Armature, 17d Press Portion, 20 Trip Button Switch, 21 Opening Spring, 50 Open/Circuit Mechanism Portion, 100 Circuit Breaker

We Claim :
[Claim 1]
A circuit breaker comprising a frame fixed to a housing, a manual handle pivotally fitted to the frame, a fixed contact conductor provided with a fixed contact, a movable contact conductor provided with a movable contact coming into and out of contact with the fixed contact, an opening spring urging the movable contact conductor in a direction open and separate from the fixed contact conductor, and an open/close mechanism portion performing ON/OFF operation of the fixed contact and the movable contact through pivot operation of the manual handle and detecting an overcurrent or a short-circuit current to perform trip operation, characterized by comprising a push plate moved upward and downward relative to the housing in engagement with the movable contact conductor, a roller engaging with an upper portion of the push plate, a link pivotally fitting the roller to a handle hole in the manual handle with a link pin, a torsion spring having a longer foot and a shorter foot and held on a spring lock axis corresponding to a pivot axis of the manual handle, and an engaging protruding portion provided on the frame near the spring lock axis and locking the crossed longer foot and shorter foot of the torsion spring, and
characterized in that the longer foot has a length to

engage with the link pin, the shorter foot has a length not to engage with the link pin, and the longer foot of the torsion spring is locked to the engaging protruding portion during the pivot operation of the manual handle.: [Claim 2]
The circuit breaker according to claim 1, characterized by further comprising a lever pivotally formed on the frame and abutting on the roller in ON and OFF states of the manual handle, and a trip bar having an end locked to the lever at least in an OFF state of the circuit breaker, and characterized in that the lock of the lever to the trip bar is released to cause pivot through moment of the torsion spring to perform trip operation. [Claim 3]
The circuit breaker according to claim 1, characterized in that the longer foot of the torsion spring is released from engagement with the link pin is locked to the engaging protruding portion during ON operation of the manual handle* [Claim 4]
The circuit breaker according to claim 1, characterized in that the link pin is locked to the longer foot of the torsion spring during OFF operation of the manual handle. [Claim 5]
The circuit breaker according to claim 1., characterized in that the torsion spring is fixed to a burring portion

protruding from the frame. [Claim 6]
The circuit breaker according to claim 5, characterized in that the axis of the manual handle is inserted through an inner hole of the burring portion protruding from the frame to serve as prevention of removal of the torsion spring. [Claim 7]
The circuit breaker according to claim 1 or 2, characterized in that the longer foot of the torsion spring is placed to engage with the manual handle or a pin inserted through and fixed to the manual handle. [Claim 8]
The circuit breaker according to claim 1 or 2, characterized in that the torsion spring is held and fixed to the handle axis.