Circuit breaker

Abstract

The purpose of the present invention is to obtain a circuit breaker that prevents swinging of a rail of a spring member, prevents winding of an arc and metal particles into the spring member, and obtains a stable biasing force generated by the spring member for pressing a movable contact toward a fixed contact. The present invention is provided with: a cross bar (30) having a wrist section (30e) and a bottom surface section (30d) having a gap (30c); a movable contact (9), one end of which is provided with a movable contact (8) that can be brought into contact with or separated from the fixed contact, and the other end of which is provided with a locking pin (31); a crimping spring (33), one end side of which is disposed between the bottom surface portion (30d) and the wrist portion (30e) of the cross bar (30) and the other end side of which is disposed on the locking pin (31) side, and which applies a rotational force to the movable contact (9), said rotational force pressing the movable contact (8) toward the fixed contact; and a spring support section (32) that engages with the locking pin (31) and has a spring support plate (32c) that supports the other end of the crimping spring (33). The spring supporting part (32) is provided with a lower plate (32a) rising from the spring supporting plate (32c), and the lower plate (32a) blocks the gap (30c) of the bottom surface part (30d) and holds the front end side of the lower plate (32a) on the bottom surface part (30d).

Description

Technical Field

[0001] The present invention relates to circuit breakers. Background Art

[0002] Circuit breakers have the function of opening and closing a circuit using an operating handle, as well as interrupting the circuit when an overcurrent flows. The circuit is opened and closed by rotating a movable contact, which is axially supported by a crossbar, to separate from a fixed contact. To maintain electrical contact between the movable and fixed contacts when the circuit is closed, the contact pressure of the movable contact against the fixed contact must be maintained stably.

[0003] Therefore, in Patent Document 1, a spring component that applies force to the movable contact in the direction of pressing the fixed contact to cause it to rotate is provided between a retaining frame serving as a cross bar that axially supports one end of the movable contact and a working pin provided on one end side of the movable contact, and a retaining component having an engaging surface that engages with the working pin and a spring supporting surface that supports one end of the spring component is provided between the spring component and the working pin, thereby efficiently transmitting the compressive force of the spring component to the movable contact.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 10-31953

[0005] In Patent Document 1, the recessed portion forming the spring support surface supporting one end of the spring member is shallow, and the spring member is exposed from the bottom of the crossbar. This causes the spring member to swing in a certain direction, resulting in a loss of applied force. Furthermore, when the circuit is interrupted, the arc gas generated at the open and close contacts is mostly extinguished by the arc extinguishing device. However, metal particles generated along with the arc at the open and close contacts and a portion of the arc scatter, passing through the arc extinguishing device and other devices, and then traveling from the bottom of the crossbar to the spring member, further reducing the applied force. Summary of the Invention

[0006] The present invention has been proposed in view of the above-mentioned situation, and its object is to provide a circuit breaker that can prevent the track of the spring member from swinging, prevent the arc and metal particles from being entangled in the spring member, and obtain a stable force generated by the spring member for pushing the movable contact toward the fixed contact.

[0007] To solve the above-mentioned problems and achieve the purpose, the circuit breaker of the present invention is characterized by comprising: a horizontal bar having an arm extending obliquely upward from a bottom portion and a bottom portion having a gap, the arm being connected to a switching mechanism that opens and closes the circuit and rotating in accordance with the operation of the switching mechanism; a movable contact axially supported by the horizontal bar, having a movable contact at one end that can contact or separate from a fixed contact, and a locking pin at the other end; a pressure spring having one end disposed between the bottom portion of the horizontal bar and the arm portion and the other end disposed on the locking pin side of the movable contact, thereby imparting a rotational force to the movable contact that presses the movable contact toward the fixed contact; and a spring support portion engaged with the locking pin and having a first plate that supports the other end of the pressure spring. The spring support portion has a second plate extending upward from the first plate, the second plate closing the gap in the bottom portion and retaining the front end of the second plate at the bottom portion.

[0008] Effects of the Invention

[0009] The circuit breaker of the present invention has the following effects: it is possible to prevent the track of the spring member from swinging, prevent arcs and metal particles from being wound into the spring member, and obtain a stable biasing force generated by the spring member for pressing the movable contact toward the fixed contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a front view showing a closed state of the circuit breaker according to the embodiment.

[0011] Figure 2 It is a cross-sectional view showing a tripped state of the circuit breaker according to the embodiment.

[0012] Figure 3 It is a cross-sectional view showing an open state of the circuit breaker according to the embodiment.

[0013] Figure 4 It is a cross-sectional view showing a closed state of the circuit breaker according to the embodiment.

[0014] Figure 5 This is an enlarged view showing a portion of a switching mechanism of a circuit breaker in a reset state according to the embodiment in a partially cutaway manner.

[0015] Figure 6 It is an enlarged view showing the surrounding structure of the movable contact of the circuit breaker in the closed state according to the embodiment.

[0016] Figure 7 It is an enlarged view showing the surrounding structure of the movable contact of the circuit breaker in the open state according to the embodiment.

[0017] Figure 8It is a perspective view showing the structure of a spring support portion of the circuit breaker according to the embodiment. DETAILED DESCRIPTION

[0018] Hereinafter, the circuit breaker according to the embodiment will be described in detail with reference to the drawings.

[0019] Implementation method.

[0020] Figure 1 1 is a front view showing the closed state of the circuit breaker 101 according to the embodiment. Figure 1 In FIG. 1 , the cover 1 which is one component constituting the housing of the circuit breaker 101 is omitted from the right half. Figure 2 It is a cross-sectional view showing a tripped state of the circuit breaker 101 according to the embodiment. Figure 3 It is a cross-sectional view showing the open state of the circuit breaker 101 according to the embodiment. Figure 4 It is a cross-sectional view showing the closed state of the circuit breaker 101 according to the embodiment. Figure 2 、 Figure 3 、 Figure 4 It is along Figure 1 The circuit breaker 101 includes a wiring breaker, an earth leakage breaker, etc. The circuit breaker 101 of the embodiment is a three-pole circuit breaker.

[0021] like Figure 1 As shown, the insulating frame of the circuit breaker 101 is composed of a cover 1 and a base 2. On the base 2, multi-phase circuit breaker units corresponding to the number of poles are arranged in parallel. Figure 1 In this case, three circuit breaking units are provided. In addition, power-side terminals 4 corresponding to the number of poles to which the power-side wires are connected and load-side terminals 5 corresponding to the number of poles to which the load-side wires are connected are provided on the base 2. An opening and closing mechanism 40 having a known toggle mechanism is provided in the central portion of the base 2 and is provided with an operating handle 3. The operating handle 3 protrudes from the handle window 1a of the cover 1 and can be operated in the direction of connection or disconnection. In addition, arc extinguishing devices 41 corresponding to the number of poles (three in this disclosure) are provided on the base 2.

[0022] like Figures 1 to 4As shown, each of the three circuit breaker units includes a fixed contact 6, a fixed contact point 7, a movable contact 9, a movable contact 8, and a tripping device 42. The fixed contact point 7 is fixedly connected to one end of the fixed contact 6, which is integrally formed with the power-side terminal 4. The load-side terminal 5 is connected to one end of the movable contact 9 via the tripping device 42. The movable contact point 8 is fixedly connected to the other end of the movable contact 9. The movable contact 9 is rotatably held by a crossbar 30. The movable contact point 8 opens and closes the circuit breaker 101 by contacting and separating with the fixed contact 7, thereby opening and closing the circuit through the power-side terminal 4 and the load-side terminal 5. The circuit breaker 101 is opened and closed by the crossbar 30, which is connected to the toggle lever of the opening and closing mechanism 40, driving the movable contact 9, which is axially supported by the crossbar 30 via the shaft 45, in the clockwise or counterclockwise direction in accordance with the movement of the opening and closing mechanism 40. The contact pressure between the fixed contact 7 and the movable contact 8 in the closed state will be described in detail later. However, this contact pressure is provided by a pressure spring 33 provided between the spring support portion 30b of the crossbar 30 and the spring support portion 32 engaged with the locking pin 31 of the movable contact 9. The arc extinguishing device 41 provided in each circuit breaking unit interrupts the arc generated between the fixed contact 6 and the movable contact 9.

[0023] Next, the structure of the opening and closing mechanism portion 40 will be described. Figure 5 1 is an enlarged view showing a portion of the switch mechanism 40 of the circuit breaker 101 in the reset state according to the embodiment. Figures 2 to 5 As shown, the opening and closing mechanism part 40 has a pair of relative frames 11, a trip bar 12, a latch 13, a stopper 14, a support member 15, a cradle 16, an upper link 17, a lower link 18, a spring pin 19 and a main spring 20. The operating handle 3 is manually operated. The handle arm 22 is mounted on the operating handle 3. The frame 11 is fixed to the base 2. The handle arm 22 is rotatably supported by the frame 11. The handle arm 22 rotates around the rotation center point 43. The operating handle 3 protrudes from the upper part of the cover 1 and rotates around the rotation center point 43 by manual operation. By rotating the operating handle 3, the handle arm 22 rotates together with the operating handle 3 around the rotation center point 43. The handle arm 22 is Figure 2 The tripped state shown is in the middle position. Figure 3 The disconnected state shown is in the right tilted position. Figure 4 The switched-on state is shown in the left-leaning position.

[0024] The upper end of the upper link 17 is rotatably supported at the link support point 44 of the cradle 16. The upper end of the lower link 18 is rotatably connected to the lower end of the upper link 17 via a spring pin 19. The upper link 17 and the lower link 18 form a toggle link. The lower end of the lower link 18 is rotatably connected to the crossbar 30. The main spring 20 has a driving side 20a and a driven side 20b. The driving side 20a is connected to the handle arm 22, and the driven side 20b is connected to the spring pin 19.

[0025] Next, the on / off operation of the movable contact 8 relative to the fixed contact 7 will be described. Figure 3 In the disconnected state shown, the movable contact 8 is separated from the fixed contact 7, and the fixed contact 7 and the movable contact 8 are in the disconnected state. In this disconnected state, the handle arm 22 is in a right tilted position, and the lower link 18 is also in a right tilted state. Figure 3 In the disconnected state shown, if the operating handle 3 is operated in the counterclockwise direction, the handle arm 22 rotates counterclockwise with the operating handle 3 around the rotation center point 43. Figure 4 By rotating the handle arm 22, the driving side 20a of the main spring 20 moves counterclockwise around the rotation center point 43 of the handle arm 22. By the counterclockwise movement of the driving side 20a of the main spring 20, the load direction of the main spring 20 changes, and the spring pin 19 moves from Figure 3 The position shown in the figure moves upward. By the movement of the spring pin 19, the lower link 18 causes the crossbar 30 to rotate counterclockwise. The movable contact 9 is supported by the shaft 45 on the crossbar 30. Therefore, if the crossbar 30 rotates counterclockwise, the movable contact 9 rotates counterclockwise around the shaft 45. As a result, the movable contact 8 on the movable contact 9 contacts the fixed contact 7, forming a Figure 4 In this connected state, the cradle 16 is held in engagement with one rotation end of the support member 15. The other rotation end of the support member 15 is engaged with the stopper 14, and the stopper 14 is engaged with the latch 13, thereby maintaining the connected state.

[0026] exist Figure 4 In the ON state shown, if the operating handle 3 is operated in the clockwise direction, the handle arm 22 rotates in the clockwise direction with the operating handle 3 around the rotation center point 43. As a result, the handle arm 22 rotates to Figure 3 By rotating the handle arm 22, the driving side 20a of the main spring 20 moves clockwise around the rotation center point 43 of the handle arm 22. By moving the driving side 20a of the main spring 20, the load direction of the main spring 20 changes, and the spring pin 19 moves from Figure 4 The position shown in FIG. 1 is moved downward. By the movement of the spring pin 19, as shown in FIG. Figure 3 As shown, the lower link 18 returns to its rightward tilt, and the crossbar 30 rotates clockwise. When the crossbar 30 rotates clockwise, the movable contact 9 rotates clockwise about the shaft 45. This causes the movable contact 8 on the movable contact 9 to separate from the fixed contact 7, resulting in an open state. In this open state, the cradle 16 is held in engagement with one rotating end of the support member 15. The other rotating end of the support member 15 is engaged with the stopper 14, which in turn is engaged with the latch 13, maintaining the open state.

[0027] Next, the tripping action is explained. Figure 4 In the on state shown, if the trip device 42 is activated by an overcurrent or the like, the trip bar 12 that cooperates with the latch 13 is pressed into the trip device 42, and the trip bar 12 and the latch 13 rotate in the counterclockwise direction. As the latch 13 rotates, the stopper 14 and the support member 15 rotate around their respective rotation axes 14a and 15a, and the engagement between the support member 15 and the cradle 16 is disengaged. The cradle 16 is constantly biased in the counterclockwise direction by the main spring 20, so that the engagement with the support member 15 is disengaged, thereby rotating in the counterclockwise direction. By the rotation of the cradle 16, the upper link 17 becomes Figure 2 In the left tilted position shown, the load direction of the main spring 20 changes, and the spring pin 19 changes from Figure 4 By moving the spring pin 19, as shown in FIG. Figure 2 As shown, the lower link 18 returns to its rightward tilted position, and the crossbar 30 rotates clockwise. When the crossbar 30 rotates clockwise, the movable contact 9 rotates clockwise about the shaft 45. This causes the movable contact 8 on the movable contact 9 to separate from the fixed contact 7, resulting in a tripped state.

[0028] Furthermore, in a mains circuit breaker where the current flowing through the circuit reaches several hundred to one thousand amperes, it is necessary to increase the biasing force of the main spring 20 to stably maintain the closed state. Therefore, the tripping load, or the force required to press the trip bar 12 in the trip device 42, is insufficient. Therefore, a three-stage latching structure is formed between the latch 13 and the cradle 16. This three-stage latching structure reduces the tripping load of the trip bar 12 applied by the main spring 20 via the stopper 14 and the support member 15.

[0029] Next, from Figure 2 The trip status shown is Figure 3 The conversion operation of the disconnected state shown in FIG. Figure 2In the tripped state shown, if the operating handle 3 is rotated clockwise, the handle arm 22 rotates the cradle 16 clockwise, and the cradle 16 begins to rotate clockwise around the rotation axis 16a. In the middle of this rotation, the support member 15 that applies force to the power side terminal 4 temporarily moves toward the load side terminal 5. If the cradle 16 is further rotated and the engagement with the support member 15 is disengaged, the support member 15 moves toward the power side terminal 4, becoming Figure 5 In this reset state, if the reset operation performed by the operating handle 3 is completed, the cradle 16 and the support member 15 are engaged due to the force of the main spring 20 and restored to Figure 3 Disconnected state shown.

[0030] Next, a structure for applying contact pressure between fixed contact 7 and movable contact 8 in the ON state will be described. Figure 6 It is an enlarged view showing the surrounding structure of the movable contact 9 of the circuit breaker 101 in the closed state according to the embodiment. Figure 7 It is an enlarged view showing the surrounding structure of the movable contact 9 of the circuit breaker 101 in the open state according to the embodiment. Figure 8 It is a perspective view showing the structure of the spring support portion 32 of the circuit breaker 101 according to the embodiment.

[0031] A contact pressure applying portion 34 for applying contact pressure between the fixed contact 7 and the movable contact 8 is provided on both sides of the movable contact 9. The contact pressure applying portion 34 includes a pressure spring 33, a spring support portion 32, a locking pin 31, and an action arm portion 35. Figure 8 As shown, the spring support portion 32 and the action arm portion 35 are integrally formed. The contact pressure spring 33 is arranged between the spring support portion 30b formed as the first spring support portion on the crossbar 30 and the spring support portion 32 formed as the second spring support portion on the movable contact 9 side.

[0032] The crossbar 30 includes a bottom portion 30d with a gap 30c formed therein, a spring support portion 30b, and an arm portion 30e extending obliquely upward from the bottom portion 30d through the spring support portion 30b, with the spring support portion 30b disposed between the bottom portion 30d and the arm portion 30e. The arm portion 30e is connected to the switching mechanism 40 that opens and closes the circuit.

[0033] The spring support portion 32 is connected to the movable contact 9 via a locking pin 31 and an operating arm 35. The locking pin 31 is inserted into a pin hole 35b of the operating arm 35. The locking pin 31 is locked in the pin hole 35b with the operating arm 35. A protrusion 35a that functions as a stopper is provided at the bottom of the operating arm 35.

[0034] The spring support portion 32 is as follows Figure 8As shown, it comprises a spring support plate 32c as a first plate that contacts the pressure spring 33, an upper plate 32b, and a lower plate 32a as a second plate. The lower plate 32a rises vertically from the spring support plate 32c and extends long.

[0035] The spring support portion 32 can freely rotate in the clockwise direction with the locking pin 31 as the axis. In the counterclockwise direction, the convex portion 35a of the action arm 35 acts as a stopper, so that the spring support portion 32 stops at the position of the contact state where the movable contact 8 and the fixed contact 7 are in contact. In the contact state where the movable contact 8 and the fixed contact 7 are in contact, as shown in FIG. Figure 6 As shown, the contact pressure spring 33 contracts, transmitting its force via the spring support 32 to the position of the locking pin 31, which is separated from the shaft 45 serving as the rotation axis of the movable contact 9. This imparts a rotational force to the movable contact 9 in the direction in which it pushes toward the fixed contact 6. As a result, contact pressure is generated between the fixed contact 7 and the movable contact 8.

[0036] Here, the crossbar 30 rotates about the shaft 45, which serves as the rotation axis of the movable contact 9. However, a gap 30c is formed in the bottom surface 30d of the crossbar 30 to prevent the contraction of the pressure spring 33 from being obstructed. Due to this gap 30c, when the lower plate 32a of the spring support portion 32 is only approximately the same length as the upper plate 32b, the pressure spring 33 bends on the bottom surface of the crossbar 30, causing the pressure spring 33 to swing. Furthermore, after the contact pressure applying portion 34 is assembled, if the pressure spring 33 swings, it is necessary to perform positional adjustment of the pressure spring 33 to correct the track.

[0037] In addition, a portion of arc gas, metal particles, coal, etc. generated between the fixed contact 7 and the movable contact 8 may be Figure 2 As shown by the arrow K, the arc extinguishing device 41 is passed through the gap 30c of the bottom surface 30d of the cross bar 30 to the crimping spring 33, and there is also the problem that the crimping spring 33 may malfunction or age.

[0038] Therefore, in the embodiment, the length of the lower plate 32a of the spring support portion 32 is set so that the gap 30c is closed and the front end side of the lower plate 32a is held on the upper surface 30a of the bottom surface portion 30d of the crossbar 30. In addition, the upper surface 30a of the bottom surface portion 30d of the crossbar 30 is formed to have a flat surface shape on which the lower plate 32a of the spring support portion 32 can slide, and is formed to have a stepped shape that can accommodate the lower plate 32a of the spring support portion 32.

[0039] As described above, by configuring the upper surface 30a of the bottom portion 30d of the crossbar 30 to have a stepped shape with a flat surface capable of accommodating the lower plate 32a of the spring support portion 32, the parallelism between the lower plate 32a and the upper surface 30a of the bottom portion 30d can be ensured, thereby stably maintaining the direction of the force lines of the pressure spring 33. Therefore, the spring support portion 32 slides on the flat upper surface 30a of the bottom portion 30d of the crossbar 30 in response to the expansion and contraction of the pressure spring 33, thereby not hindering the expansion and contraction of the pressure spring 33. Furthermore, by arranging the lower plate 32a of the spring support portion 32 along the upper surface 30a of the bottom portion 30d of the crossbar 30 to accommodate the pressure spring 33, the pressure spring 33 does not flex on the bottom surface side of the crossbar 30 during assembly of the contact pressure imparting portion 34. This eliminates the need for positional adjustment of the pressure spring 33 after assembly, thereby improving assembly efficiency.

[0040] In addition, the gap 30c of the bottom portion 30d of the cross bar 30 is blocked by the lower plate 32a, so there is no need to modify the shape of the cover 1 and the base 2, or to add other molded bodies inside the insulating frame. This can prevent arc gas, metal particles, etc. generated by short circuit breaking from being wound around the crimping spring 33, and the rated short circuit breaking capacity can be expected to be upgraded without increasing the number of components.

[0041] As described above, in the embodiment, the track of the pressure spring 33 can be prevented from swinging, arcs and metal particles can be prevented from being wound into the pressure spring 33, and a stable biasing force generated by the pressure spring 33 for pressing the movable contact 8 toward the fixed contact 7 can be obtained.

[0042] The structure shown in the above embodiment represents an example of the content of the present invention and can also be combined with other well-known technologies. The structures of each embodiment can be appropriately combined with each other, and part of the structure can be omitted or changed without departing from the scope of the main purpose of the present invention.

[0043] Description of the label

[0044] 1 Cover, 1a Handle window, 2 Base, 3 Operating handle, 4 Power supply side terminal, 5 Load side terminal, 6 Fixed contact, 7 Fixed contact, 8 Movable contact, 9 Movable contact, 11 Frame, 12 Trip bar, 13 Latch, 14 Stopper, 14a, 15a, 16a Rotating shaft, 15 Support, 16 Cradle, 17 Upper link, 18 Lower link, 19 Spring pin, 20 Main spring, 20a Driving side, 20b Driven side, 22 Handle arm, 30 Crossbar, 30a upper surface, 30b, 32 spring supporting parts, 30c gap, 30d bottom part, 30e wrist, 31 locking pin, 32a lower plate, 32b upper plate, 32c spring supporting plate, 33 pressure contact spring, 34 contact pressure applying part, 35 action wrist, 35a convex part, 35b pin hole, 40 opening and closing mechanism part, 41 arc extinguishing device, 42 tripping device, 43 rotation center point, 44 connecting rod support point, 45 axis, 101 circuit breaker.

Claims

1. A circuit breaker, characterized in that: have: a horizontal bar having a bottom portion with a gap and an arm portion extending obliquely upward from the bottom portion, the arm portion being connected to a switching mechanism portion for opening and closing a circuit and rotating in accordance with the operation of the switching mechanism portion; A movable contact piece, the axis of which is supported by the crossbar, is provided with a movable contact point at one end that can contact or separate with the fixed contact point, and a locking pin at the other end; a pressure spring having one end disposed between the bottom portion of the crossbar and the arm portion and the other end disposed on the locking pin side of the movable contact, and imparting a rotational force to the movable contact to press the movable contact toward the fixed contact; as well as a spring support portion engaged with the locking pin and having a first plate for supporting the other end of the pressure contact spring; The spring support portion includes a second plate standing upright from the first plate, and the second plate closes the gap in the bottom surface portion to hold the front end side of the second plate on the bottom surface portion.

2. The circuit breaker according to claim 1, wherein: A step having a flat surface on which the second plate slides is provided on the upper surface of the bottom portion.

3. The circuit breaker according to claim 1 or 2, characterized in that: An arc extinguishing device capable of extinguishing an arc generated between the fixed contact and the movable contact is provided, and metal particles from the arc extinguishing device passing through the gap are blocked by the second plate.

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