JP2603619B2 - Circuit breaker for wiring - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a circuit breaker for wiring, and more particularly, to a circuit breaker for wiring that opens a contact device when an excessive current passes.

BACKGROUND ART As shown in FIG. 9, the present inventors hold a movable contact 31 by a contact holder 33 rotatable at a fixed position in a housing 1 and make contact with the movable contact 31. The contact pressure spring 34 is interposed between the contact holder 33 and the contact holder 30 to apply a contact pressure to the movable contact 31 when the contact device 30 is closed and to move the movable contact 31 when the contact device 30 is opened. We have previously developed a circuit breaker for biasing the movable contact 31 so that the contact 32 is separated from the fixed contact 35. This contact pressure spring 34 is a movable contact
The movable contact 32 is provided on the lower surface of the left end of the movable contact 31, and is provided at the lower surface of the right end of the movable contact 31. Is a shaft pin 38 provided at the center of the movable contact 31. When the contact device 30 starts rotating clockwise in the drawing when the contact device 30 is opened, one end of the movable contact 31 Contact pressure spring
As a result, there is a problem that rotation of the movable contact 31 is hindered. That is, the opening distance becomes insufficient, and a high arc voltage cannot be obtained. Further, in the circuit breaker of this structure, the contact pressure spring 34 is interposed between the movable contact 31 and the contact holder 33 on the lower surface side of the movable contact 31, and the contact pressure spring 34 is narrow below the movable contact 31. Contact pressure spring from space 34
And it is difficult to incorporate the contact pressure spring 34.

[Object of the Invention] The present invention has been made in view of the above points, and a main object of the present invention is to prevent the contact pressure spring from hindering the movement of the movable contact when the contact device is opened. Accordingly, it is an object of the present invention to provide a circuit breaker for wiring in which a high arc voltage can be obtained and a contact pressure spring can be easily incorporated.

[Disclosure of the Invention] (Embodiment 1) In the following description, the directions of up, down, left, and right in FIG. 1 are used for convenience, but the mounting direction is not limited.

As shown in FIG. 1, the basic configuration includes an overcurrent detection device 10 that is driven when an overcurrent passes, and a trip device that performs a trip operation when the overcurrent detection device 10 is driven.
20, a contact device 305 that opens when the trip device 20 performs a trip operation, and an arc-extinguishing device 40 that extinguishes an arc generated when the contact device 30 is opened. From the top of the housing 1
The handle 50 linked to 20 protrudes up and down freely. Terminals 2a and 2b are exposed at both ends of the housing 1, respectively, and a main electric path is formed between the terminals 2a and 2b.

The overcurrent detection device 10 includes an electromagnetic detection device 10a and a thermal detection device 10b. Electromagnetic detection device 10a
A coil unit 11 inserted into the main electric circuit, a plunger 12 attracted downward by a magnetic force generated around the coil unit 11 when an excessive current passes through the coil unit 11, and a plunger 12
And a return spring 13 for urging the spring upward. One end of the coil unit 11 is connected to the terminal 2a. Thermal detector 10b
Is composed of a heater plate 14 inserted into the main electric circuit, a bimetal plate 15 disposed so as to overlap with the heater plate 14, and the like.
Is connected to the other end of the coil 11. Heater plate
The other end of the connecting wire 16 formed of a braided wire whose one end is connected to the movable contact 21 is connected to the upper end of the. Bimetallic boards15
When the heater plate 14 generates heat due to the passage of an overcurrent, the upper end is bent to the left. The electromagnetic detection device 10a and the thermal detection device 10b are the housing 1
The operating bar 17 which is pivotally supported at the predetermined position is operated. Actuation bar
Reference numeral 17 is arranged such that the plunger 12 moves downward or rotates counterclockwise when the upper end of the bimetal plate 15 curves to the left. The operating bar 17 has a locking piece 18 on the left.
The retaining piece 18 is formed with a holding groove 19 having an open front end surface.

The trip device 20 includes a holding frame 21 fixed at a fixed position in the housing 1, and a latch link 22 is pivotally supported by a shaft pin 23 at the right end of the holding frame 21. The latch link 22 extends a latch piece 22a to the lower right with respect to the shaft pin 23, and the latch piece 22a is inserted into a holding groove 19 formed in the operation bar 17. A spring receiving piece 22b is formed on the right side of the shaft pin 23. Pressing piece on the left side of the axis pin 23 above the axis pin 23 of the latch link 22
22c is extended, and the upper end of the locking lever 24 contacts the lower surface of the pressing piece 22c. The lower end of the locking lever 24 is pivotally supported on the holding frame 21 by a shaft pin 25 so as to be swingable.
A locking hole 24a is formed above. Latch link 22
Both pieces of the scissor spring 26 held by the holding frame 21 are in contact with the right side surface of the spring receiving piece 22b and the upper edge of the opening of the locking hole 24a. The scissor spring 26 has a spring force in a direction to reduce the distance between the tips of the two pieces, so that the latch link
22 is urged counterclockwise around the shaft pin 23 and the locking lever
Energize 24 clockwise about shaft pin 25. Lock lever 24
The locking hole 24a has a locking projection 27a extending from the cradle 27.
Is inserted. The lower end of the cradle 27 is pivotally attached to the holding frame 21 by a pivot pin 28. A shaft projection 27b is formed at the upper end of the cradle 27, and the upper end of the first link 61 is rotatably mounted on the shaft projection 27b. Cradle
At 27, a pressing protruding piece 2 is provided at the end opposite to the locking protruding piece 27a.
7c is extended.

The lower end of the first link 61 is rotatably connected to the upper end of the second link 62 by a shaft pin 63. One end of a tension spring 64 is connected to the shaft pin 63. The other end of the tension spring 64 is connected to the upper end of the handle link 51. The handle link 51 has an upper end integrally connected to the handle 50. A lower end edge of the handle link 51 is formed with a U-shaped bearing groove 51a opened downward. The bearing groove 51a is formed on the outer surface of the holding frame 21 by a stamping or burring process. Engage with 52, handle link 51
Is swingable together with the handle 50. A holding band 53 bulging in the same direction as the shaft portion 52 in a direction perpendicular to the paper surface of FIG. 1 is formed above the shaft portion 52 in the holding frame 21. The holding band 53 is formed by embossing a portion between a pair of upper and lower cutting grooves 54 running in the left-right direction. Therefore, a slit is formed between the holding frame 21 and the holding band 53 in a direction perpendicular to the paper surface of FIG. 1 so that the lower end of the handle link 51 is inserted into the slit. It has become. With this configuration, the handle link 51 is prevented from dropping off the shaft portion 52 in a direction perpendicular to the paper surface of FIG. A pressing pin 55 is attached to a portion of the handle link 51 projecting above the holding frame 21. A U-shaped connecting groove 62a is formed at the lower end of the second link 62.
Is connected to the contact device 30.

The contact device 30 includes a movable contact 31 having a movable contact 32 on the lower surface of the left end, and a contact holder 33 for holding the movable contact 31.
, A contact pressure spring 34 interposed between the contact holder 33 and the movable contact 31, and a fixed contact 35 provided integrally with the arc extinguishing device 40 described later. The movable contact 31 has a heater plate 14
The other end of the connection line 16 whose one end is connected to the other end is connected. The contact holder 33 is integrally formed with an insulating material such as a synthetic resin molded product together with a cross bar 36 pivotally supported at a fixed position in the housing 1, and has a slit at the left end portion which is spaced apart in the axial direction of the cross bar 36. Is formed, and the movable contact 31 is inserted into the slit. The peripheral wall of the slit projects inward from the inner side surface of the contact holder 33 to form a holding projection 33a. At the right end of the upper wall of the contact holder 33, a spring receiving seat 37 having an edging is formed, and the spring receiving seat 37 is provided with a spring receiving projection 37a projecting obliquely downward so as to straddle the edge. Have been. On the inner peripheral surface of the contact holder 33, a holding groove 33b is formed which is opened inside and rightward of the contact holder 33. The movable contact 31 has a shaft pin 3 serving as a fulcrum at a substantially central portion on the left and right sides, and a spring receiving tongue piece 31a projecting rightward at the upper edge of the right end of the movable contact 31.
Are formed, and the spring receiving pin 31b is inserted into the spring receiving tongue piece 31a. The contact pressure spring 34 of the compression spring is sandwiched between the edge and the spring receiving tongue 31a of the movable contact 31 with a spring receiving projection 37a inserted at one end. The contact pressure spring 34 can swing freely by contacting the edge. On the side of the spring receiving tongue piece 31a, the contact pressure spring 34 is swingable when the spring receiving pin 31b contacts the end of the contact pressure spring 34 as shown in the drawing. The shaft pin 38 is inserted into the holding groove 33b, and is rotated by the spring force of the contact pressure spring 34.
The movable contact 31 is urged so that moves toward the tip of the holding groove 33b. The second link 62 is rotatably locked to the shaft pin 38, and the second link 62 is urged leftward by the spring force of the contact pressure spring 34. Therefore, the right surface of the holding projection 33a, which is the peripheral wall of the slit, is provided. And the shaft pin 38. Further, in the axial direction of the shaft pin 38, the movable contact 31 and the inner peripheral surface of the contact holder 33 are inserted between the movable contact 31 and the inner circumferential surface of the contact holder 33 to prevent the contact. When the movable contact 31 and the contact pressure spring 34 are incorporated in the contact holder 33, the movable contact 31 is inserted from the right side in FIG. 3 and the shaft pin 38 is inserted into the holding groove 33b. 31 is attached rotatably, and the movable contact
The movable contact 32 is rotated as far as possible so that the movable contact 32 goes upward in FIG. 3, and in this state, the contact pressure spring 34 is inserted from the right side to make contact between the spring receiving tongue piece 31a and the spring receiving seat 37. A pressure spring 34 is interposed.

A fixed contact 35 that forms a contact together with the movable contact 32 is provided on an upper surface of a fixed contact plate 41 of the arc extinguishing device 40, and an arc traveling plate 42 is provided at one end of the fixed contact plate 41. One end of the drive coil 43 is connected to an end of the fixed contact plate 41 opposite to the arc traveling plate 42 with the fixed contact 35 interposed therebetween. The drive coil 43 is bent in a U-shape that is open downward, and is disposed such that the fixed contact 35 is located at a position corresponding to a position between both legs of the drive coil 43. The other end of the drive coil 43 is connected to a terminal plate 44. One end of the terminal plate 44 protrudes from the side surface of the housing 1 to form a terminal 2b. An arc extinguishing grid device 45 is provided above the arc traveling plate 42. The arc-extinguishing grid device 45 includes a plurality of grid plates 46, which are conductive plates disposed in parallel in a vertically separated manner, and a grid plate 46.
And a holding frame 47 formed of an insulating material for holding the lowermost grid plate 46, and the lowermost grid plate 46 is arranged so as to face the arc traveling plate 42.

As described above, the terminal 2a, the coil portion 11, and the heater plate 14
−Connection line 16−Movable contact 31−Movable contact 32−Fixed contact 35−
The main electric path is formed by the path of the fixed contact plate 41, the drive coil 43, the terminal plate 44, and the terminal 2b.

(Operation) The operation will be described below. First, as shown in FIG.
When the handle 50 is tilted to the right, the contact device 30
Is open. In this state, the latch piece 22a of the latch link 22 is inserted into the holding groove 19 of the operation bar 17, and the latch link 22 is urged counterclockwise around the shaft pin 23 by the scissor spring 26. Pressing piece 22c of latch link 22
Is in contact with the upper edge of the locking lever 24, and the locking lever 24 is urged clockwise around the shaft pin 25 by the scissor spring 26. Here, the latch link 22 and the locking lever
The rotation of both is stopped by the contact with 24. The locking projection 24a of the cradle 27 is inserted into the locking hole 24a of the locking lever 24, and the rotation of the cradle 27 is stopped. On the other hand, the line of action of the tension spring 64 passes on the right side of the shaft projection 27b, and an upward spring force acts on the shaft pin 63 connecting the first link 61 and the second link 62. It is urged counterclockwise around the shaft projection 27b. Accordingly, the second link 62 is lifted up together with the movable contact 31, the movable contact 32 and the fixed contact 35 are separated from each other, and the contact holder 33 holding the movable contact 31 is urged clockwise. You.

Next, as shown in FIG. 2, when the handle 50 is tilted to the left, the action line of the tension spring 64 passes on the left side of the shaft portion 52, and the spring force acts on the handle link 51 downward. , The handle link 51 is urged counterclockwise, and the handle
The state that 50 was knocked down to the left is maintained. Further, in this state, the action line of the tension spring 64 is connected to the shaft pin 28 which supports the cradle 27.
Therefore, the cradle 27 is urged counterclockwise because the spring force acts upward on the cradle 27 and passes on the right side. On the other hand, since the shaft pin 63 connecting the first link 61 and the second link 62 is pulled to the left by the spring force of the tension spring 64, the first link 61 and the second link 62 are substantially aligned. That is, the movable contact 31 connected to the lower end of the second link 62 is pressed downward, and the movable contact 32 and the fixed contact 35 come into contact. Further, the contact pressure is obtained by the action line of the contact pressure spring 34 passing above the shaft pin 38 and the spring force acting on the movable contact 31 to the left. Thus, when the handle 50 is tilted to the left, the set state is reached in which the spring force of the tension spring 64 is accumulated.

As described above, when a large current such as a short-circuit current flows in the main circuit when the contact device 30 is in the closed state, first, as shown in FIG. The movable contact 31 moves upward due to the Lorentz force between the movable contact 31 and the magnetic field generated around the movable contact 32, and the movable contact 32 and the fixed contact 35 are separated from each other. At this time, the line of action of the contact pressure spring 34 on the movable contact 31 passes through the right side of the shaft pin 38, and the spring force acts on the movable contact 31 downward. The contact 32 will be biased away from the fixed contact 35. Since one end of the contact pressure spring 34 is in contact with the edge, the direction of the action line can be changed so as to effectively apply a spring force to the movable contact 31. That is, since the contact pressure spring 34 comes into contact with the edge and is swingable, the action direction of the spring force is accurately set. When the contact device 30 is closed, the contact pressure is applied, When the device 30 is opened, it acts as a reversing spring that accelerates the opening of the contact device 30. here,
The contact pressure spring 34 is disposed above the movable contact 31, and when the contact device 30 opens due to the trip operation of the trip device 20, the left end of the movable contact 31 moves upward. When the spring receiving tongue piece 31a exceeds the line connecting the shaft pin 38 and the spring receiving seat 37, the right end of the movable contact 3 is pushed downward by the contact pressure spring 34, and the right end of the movable contact 31 is pressed. Move in a direction away from the contact pressure spring 34, the movement of the movable contact 31 is not hindered by the contact pressure spring 34, and the opening distance between the movable contact 32 and the fixed contact 35 as shown in FIG. Is sufficiently large, and a high arc voltage can be obtained. The arc generated by the opening of the contact device 30 is urged toward the arc-extinguishing grid device 45 by Lorentz force, which is an interaction between the magnetic field generated around the drive coil 43 and the arc. As a result, the arc length is rapidly extended, the arc voltage is increased, the arc current is suppressed, and the introduction of the arc into the arc-extinguishing grid device 45 becomes easy, and the arc is extinguished rapidly. is there.

Following the opening of the contact device 30 by the Lorentz force between the drive coil 43 and the movable contact 31, the electromagnetic detection device
The trip device 20 is driven by 10a. That is, when a large current passes through the coil portion 11 of the electromagnetic detection device 10a, the plunger 12 is pulled downward against the spring force of the return spring 13, and the operation bar 17 rotates counterclockwise. Thus, the latch piece 22a of the latch link 22 is pressed downward by the peripheral wall of the holding groove 19. That is, the latch link 22 rotates right against the spring force of the scissor spring 26, and the pressing force on the locking lever 24 is released.
Then, the locking projection 27a of the cradle 27 is disengaged from the locking piece 24a of the locking lever 24. As described above, since the cradle 27 is urged counterclockwise by the spring force of the tension spring 64, when the engagement with the locking lever 24 is released, the cradle 27 rotates counterclockwise to move the first link 61 to the upper left. Pull up.
When the first link 61 is pulled up, the second link 62 is pulled up together with the contraction of the tension spring 64, and the movable contact 31 is pulled up so as to separate the movable contact 32 from the fixed contact 35. These series of operations are performed instantaneously, and a so-called trip operation is performed. Here, the movable contact 31 is inserted into a slit formed in the contact holder 33, and the contact pressure spring 34 is housed in the contact holder 33, while the movable contact 32 is connected to the contact holder 33. Since the movable contact 32 and the contact pressure spring 34 are provided outside and the contact pressure spring 34 is
a, the arc accompanying the opening of the contact device 30 is directly transferred to the contact pressure spring 34, and the contact powder generated when the arc is generated adheres to the contact pressure spring 34. This prevents the contact spring 34 from changing over time.

As described above, when a large current passes, the electromagnetic detection device 10a operates to drive the trip device 20, but when an overcurrent slightly larger than the rating is supplied for a long time, the heater plate The heating of the bimetal plate 15 causes the upper end of the bimetal plate 15 to bend and press the operating bar 17 to rotate counterclockwise, and the trip device 20 is operated and the contact device is operated in the same manner as described above. 30 can be opened.

Thus, when the trip device 20 operates, the cradle
Since 27 is disengaged from the locking lever 24, the contact device
To close 30 again, a reset must be performed.
The reset is carried out by operating the handle 50 to the right as far as possible. That is, when the handle 50 is tilted to the right as much as possible, the pressing pin 55 provided on the handle link 51 presses the pressing protrusion 27c of the cradle 27 rightward, and the cradle 27 rotates clockwise. With this operation, the locking projection 27a of the cradle 27 is inserted into the locking hole 24a of the locking lever 24,
The locking lever 24 rotates counterclockwise by the pressing force from the cradle 27. Therefore, the upper end of the locking lever 24 is
The holding member 22c comes into contact with the lower surface of the holding piece 22c, and if the force for tilting the handle 50 rightward is removed, the state returns to the state shown in FIG.

According to the above-described configuration, one end of the contact pressure spring 34 is in contact with the spring receiving seat 37 having the edge, so that the contact pressure spring 34 contacts the edge at two points located at both ends in the diameter direction with respect to the edge. become. The contact pressure spring 34 is a coil spring, and generally has a winding end formed to have the same diameter as the other portions, so that a step is formed at the winding end portion. That is, when the spring receiving seat 37 having the edge is brought into two-point contact, as shown in FIG. 4 and FIG.
The position at which the terminal end contacts the spring receiving seat 37 changes depending on how the 34 is attached. In this case, since the amount of expansion and contraction of the contact pressure spring 34 changes, the spring force changes, and since the line of action is inclined, a constant contact pressure may not be obtained. As a method for solving such a problem, as shown in FIG. 6, the end face of the contact pressure spring 34 is polished so that the end face is flush with a plane perpendicular to the axial direction of the contact pressure spring 34. However, there is a problem that the polishing work is troublesome and the cost is high.

Accordingly, as shown in FIG. 7, the winding end portion of the contact pressure spring 34 is wrapped around (winding with overlapping in the radial direction).
Thereby, the end face of the contact pressure spring 34 is flush. As shown in FIG. 8, the contact pressure spring 34 thus formed can maintain a constant spring force irrespective of the end position of the contact pressure spring 34, and the inclination of the action line also occurs. It does not. Needless to say, this technique can be used not only for the contact pressure spring 34 but also for compression coil springs in general.

[Effect of the Invention] As described above, according to the present invention, the contact device includes a contact holder that has a holding groove that is opened on the right side and closed on the left side and that is rotatably held in the housing. Having a movable contact opposing the fixed contact so as to be able to freely contact and separate from the fixed contact on the lower surface side,
A movable contact rotatably supported by being inserted from the right side to the left side of the contact holding member so that the intermediate portion is engaged with the holding groove and rotatably supported, and a spring receiving tongue on the right end side of the movable contact A contact pressure spring of a compression spring sandwiched between the piece and the spring receiving seat on the right side of the contact holder, wherein the contact pressure spring is disposed on the upper surface side of the movable contact and a trip device. When the left end of the movable contact is rotated to the upper side to the maximum, the movable contact is rotatable to the contact holder so that the spring receiving tongue is positioned on the lower side from the spring receiving seat. Because the shaft is supported, the contact pressure spring does not hinder the movement of the movable contact when the contact device is opened, so that the movable contact can be sufficiently separated from the fixed contact, and as a result, the opening distance is reduced. It is sufficiently large to obtain a high arc voltage, and the effect of suppressing the current peak value Ku, and it has a advantage that interruption time is shortened. In addition, since the effect of suppressing the arc current is high, stable operation characteristics can be obtained even when a high voltage is cut off. Further, when assembling the contact holder, the movable contact and the contact pressure spring, the movable contact is inserted through the contact holder from the right side to the left side of the contact holder and into the holding groove. A state in which the movable contact is rotatably mounted on the contact holder by engaging the middle portion of the movable contact, and then the trip device is tripped and the left end of the movable contact is rotated to the upper side to the maximum. The contact pressure spring of the compression spring is inserted between the spring receiving seat and the spring receiving tongue which opposes in the vertical direction from the right side of the contact holder, and is sandwiched between the spring receiving seat and the spring receiving tongue. The movable contact and the contact pressure spring can be easily incorporated into the contact holder, and especially the attachment of the contact pressure spring of the compression spring, which is difficult to attach. Has the effect of being easily retrofitted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a contact device according to an embodiment of the present invention in an open state, FIG. 2 is a cross-sectional view of the same contact device in a closed state, and FIG. FIG. 4 and FIG. 5 are enlarged views of a main part showing a problem of the contact pressure spring, FIG. 6 is a front view showing an example of the contact pressure spring, FIG. FIG. 8 is an enlarged view of a main part showing another example of the contact pressure spring. FIG.
The figure is a sectional view showing a conventional example. 1 is a housing, 10 is an overcurrent detection device, 20 is a trip device, 21 is a holding frame, 30 is a contact device, 31 is a movable contact, 31a is a spring receiving tongue, 32 is a movable contact, and 33 is a contact holder. , 33b are holding grooves, 34 is a contact pressure spring, 37 is a spring seat, 6
1 is a first link and 62 is a second link.

Continuation of the front page (72) Inventor Takanobu Tanaka 1048 Kadoma, Kadoma City Matsushita Electric Works Co., Ltd. (56) References JP-A-62-163236 (JP, A) JP-A-57-53555 (JP, U) Opened 52-662 (JP, U) Opened 59-36558 (JP, U)

Claims (1)

(57) [Claims] 1. An overcurrent detecting device driven by passage of an excessive current and a plurality of links and springs mounted on a holding frame, and the overcurrent detecting device is driven in a set state in which spring force is accumulated. A trip device that performs a trip operation and a contact device that is opened with the trip operation of the trip device are housed in a housing, and the contact device is opened on the right side and closed on the left side. A contact holding member having a holding groove and rotatably held in the housing, and a movable contact opposing the fixed contact so as to be able to contact and separate from the fixed contact on a lower surface side of a left end portion, and a right side of the contact holding member. The movable contact is rotatably supported by inserting the middle part into the holding groove from the left side of the movable contact, the spring receiving tongue on the right end side of the movable contact and the right of the contact holder. Pressure of the compression spring sandwiched between the spring seat on one side The contact pressure spring is arranged on the upper surface side of the movable contact, the trip device trips, and the left end of the movable contact is rotated to the upper surface side to the maximum extent. A circuit breaker for wiring, wherein a movable contact is rotatably supported by a contact holder so that a tongue piece is located on a lower surface side.