JPH0785390B2 - Circuit protector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a circuit protector that opens a breaking contact inserted in series in a main current path when an overcurrent flows.

BACKGROUND ART Generally, a circuit protector of this type has a movable contact in which a breaking contact constituted by a fixed contact and a movable contact and a detection element such as a solenoid for driving an amateur by an overcurrent are inserted in series in a main conduction path. By connecting the movable contact plate with contacts to the armature via the trip mechanism, the balance of the trip mechanism is disrupted and shut off by utilizing the fact that the armature moves when overcurrent flows in the main energization path. The contacts are opened. By the way, the conventional trip mechanism has, as shown in FIGS. 6 and 8, a frame 42 having a long hole 41 for supporting both ends of a rotary shaft 40 provided at the center of the movable contact plate 4 '. An opening spring 11 'for urging the movable contact plate 4'in a direction in which the breaking contact A is opened, a latch link 43 engaged with one end of the movable contact plate 4', and an overcurrent in the main energizing path. When a current flows, it is constituted by a trip plate 45 which is attracted by an electromagnet 44 as an overcurrent detection element and presses the latch link 43 in a direction in which the engagement state with the movable contact plate 4'is released. Here, the trip plate 45 is rotatably supported by the frame 42, and is biased by the return spring 46 in a direction in which the trip plate 45 is separated from the latch link 43. When an overcurrent flows in the main energizing path, as shown in FIG. 7, one end of the trip plate 45 is attracted to the electromagnet and the other end of the trip plate 43 is latched.
The latch link 43 and the movable contact plate 4'are disengaged from each other, and the movable contact plate 4'rotates around the rotating shaft 41 by the spring force of the opening spring 11 'to shut off. The contact A is opened. In such a trip mechanism, there is a problem that the structure is complicated and many component parts are required as described above.

[Object of the Invention] The present invention has been made in view of the above points, and an object of the present invention is to provide a circuit protector having a relatively small number of constituent parts, and another object. Is to provide a circuit protector having a high response speed when an overcurrent passes.

DISCLOSURE OF THE INVENTION (Embodiment) FIGS. 1 and 2 show an embodiment of the present invention, in which a first terminal plate 2 fixed at a fixed position of a casing 1 and having one end protruding from the casing 1 Fixed contacts 3 are provided at the multi-ends of the. A movable contact 5 is provided at one end of the movable contact plate 4 at a position corresponding to the fixed contact 3 and constitutes a breaking contact A together with the fixed contact 3. The movable contact plate 4 is connected to the coil 7 via a connecting wire 6. It is electrically connected to one end.
One end of the coil 7 is electrically connected to the second terminal plate 8 protruding from the casing 1 at the other end. That is,
The breaking contact A and the coil 7 are inserted in series in the main conduction path formed between the first terminal plate 2 and the second terminal plate 8. One end of the movable contact plate 4 opposite to the movable contact 5 is loosely fitted to the trip plate 9 so as to be vertically swingable, and a locking piece 13 for preventing slippage is provided at the tip of the movable contact plate 4. Has been formed. Both ends of the trip plate 9 in the width direction are slidably accommodated in guide grooves 10 provided in the casing 1 and running in the vertical direction, and the trip plate 9 is regulated so as to be movable only in the vertical direction. Further, one end of the movable contact plate 4 has an opening spring whose one end abuts on a rib 12 provided on the casing 1.
11 is arranged, and the movable contact plate 4 is biased upward by the opening spring 11. At the center of the movable contact plate 4, a reset button has one end protruding from the casing 1 so as to be able to move back and forth.
A lower end of the reset button 30 is in contact with the reset button 30, and a locking portion 31 is formed at the lower end of the reset button 30 to prevent the reset button 30 from coming off from the casing 1 and to be tapered toward the lower side. An engaging hole 14 is formed at the lower end of the trip plate 9, and the tip of an armature 16 of a solenoid 15 as a detecting element is inserted into the engaging hole 14. Solenoid 15
Is the coil 7 and a coil bobbin around which the coil 7 is wound.
17, an armature 16 that is inserted into the coil bobbin 17 so as to move back and forth, and a yoke 18 that forms a magnetic path together with the armature 16.
And a bias spring 19 which is installed in the coil bobbin 17 and biases the armature 16 so as to project from the coil bobbin 17.
And a coil spring 20 made of a shape memory alloy material that is installed in the coil bobbin 17 and expands in a direction that resists the spring force of the bias spring 19 when heated above the transformation temperature, inside the coil bobbin 17 of the amateur 16. An outer flange 21 is formed at the inserted one end, and a bias spring 19 and a coil spring 20 are configured to urge the armature 16 with the outer flange 21 interposed therebetween. A fitting hole 22 is formed further below the trip plate 9, and one end of an auxiliary contact plate 23 made of a conductive material having elasticity is inserted therein. That is, the auxiliary contact plate 23 is substantially U opened downward.
The bent piece is shaped like a letter, the engaging piece 24 accommodated in the fitting hole 22 is extended from the tip of one of the vertical pieces, and the contact piece 25 is provided on the other vertical piece. The other vertical piece is extended to the outside of the casing 1 to form a terminal plate. The contact 25 is a terminal plate fixed in place on the casing 1.
The contact 27 is disposed opposite to the contact 27 provided on the switch 26, and constitutes an auxiliary contact together with the contact 27. This auxiliary contact is used for controlling alarm means or the like for notifying that the circuit protector is actuated by the overcurrent flowing in the main energizing path and the breaking contact A is opened. Also, auxiliary contact plate
An insulating layer 28 such as a synthetic resin is interposed between 23 and the terminal plate 26 so that the auxiliary contact plate 23 and the terminal plate 26, which are arranged close to each other, are not short-circuited outside the casing 1. .

The operation of the embodiment will be specifically described below. Now
FIG. 1 shows the ON state when set, and FIG. 2 shows the trip state. At the time of setting, as shown in FIG. 1, the fixed contact 3 and the movable contact 5 come into contact with each other, and the breaking contact A becomes It is closed. In this state, the contact spring 4 is compressed by the movable contact plate 4, the trip plate 9 is located at the lower position, and one end of the armature 16 of the solenoid 15 is inserted into the engagement hole 14 of the trip plate 9. Therefore, the trip board 9
Is prohibited from moving upward, the breaking contact A is maintained in the closed state, and the auxiliary contact constituted by the contacts 25 and 27 is opened. When an overcurrent flows through the coil 7 in this state, as shown in FIG. 2, due to the magnetic force generated by the coil 7 and the expansion of the coil spring 20 formed of the shape memory alloy material due to the heat generation of the coil 7, the amateur
16 is drawn into solenoid 15. Here, since the resultant force of the magnetic force and the force when the coil spring 20 expands acts on the amateur 16, the amateur 16 is pulled in by a large force and makes a sharp movement. In addition, the coil spring 20 is an indirectly heated type in which the coil 7 is indirectly heated, and the coil spring 20 is
Since it is installed inside, the overcurrent detecting element can be downsized, and the arc extinguishing chamber in the casing 1 can be made large. When the armature 16 is pulled into the solenoid 15, the engagement between the trip plate 9 and the armature 16 is released, the trip plate 9 moves upward, and the one end of the movable contact plate 4 has the spring force of the opening spring 11. Is flipped up by. Here, since the lower end of the reset button 30 is in contact with the central portion of the movable contact plate 4,
The movable contact plate 4 rotates with the lower end of the reset button 30 as a fulcrum, and the movable contact 5 separates from the fixed contact 3. That is,
The breaking contact A opens. During this time, only the three parts, the armature 16, the trip plate 9 and the movable contact plate 4, move, so the time from the overcurrent flowing to the coil 7 to the opening of the breaking contact A is extremely short. And has excellent blocking characteristics. When the trip plate 9 moves upward, the auxiliary contact plate 23 bends and the auxiliary contact is closed. To reset the tripped state to the original state, the reset button 30 is pressed downward. That is, when the reset button 30 is pressed downward, the movable contact plate 4
Moves downward, the opening spring 11 is compressed, and the trip plate 9 also moves downward. Then, immediately after the trip, the coil spring 20 radiates heat and is below the transformation temperature, so when the engaging hole 14 is lowered to a position corresponding to the amateur 16, the amateur force is generated by the bias spring 19.
The tip of 16 projects from the solenoid 15 and fits into the engagement hole 14. When the reset button 30 is pressed, the movable contact plate 4 is pressed downward even when the tip of the armature 16 is fitted into the engagement hole 14 of the trip plate 9 and the breaking contact A is opened. However, by releasing the reset button 30,
The breaking contact A is closed by the pressing force of the opening spring 11, and the contact pressure is applied by the opening spring 11.

By the way, the movable contact plate 4a may be formed in a bifurcated shape as shown in FIG. 3, and in this case, the movable contact 5a is provided at each of the bifurcated front ends, and Contacts 5a, 5b
The fixed contacts 3a and 3b are formed corresponding to the. The other end of the first fixed contact plate 2a having the fixed contact 3a at one end projects from the casing 1 and the other end of the second fixed contact plate 2b having the fixed contact 3b at one end. The coil 7 is connected to. Therefore, the connection line is not necessary here, and there is no risk of disconnection of the connection line or short circuit of the breaking contact A due to contact of the connection line with the fixed terminal plate 3. Further, if the height positions of the fixed contacts 3a and 3b are made different in the direction in which the breaking contact A opens, and a step is provided on both fixed contacts 3a and 3b, the movable contacts 5a and 5b and the fixed contacts 3a and 3b are separated from each other. The contact opening order can always be made constant, and the contact areas of the contacts 3b, 5b that leave first are the same as those of the other contact 3.
If it is made larger than the contact area of a and 5a, the arc generated at the opening can be well absorbed.

In the above-mentioned example, the example in which the locking piece 13 is formed to prevent the movable contact plate 4 from coming off from the trip board 9 is shown. However, as shown by the imaginary line in FIG. Ring 13
a may be provided, and the shaft 13b is provided at the center of the movable contact plate 4.
Alternatively, the end of the shaft 13b may be fitted in a guide groove 13c provided in the casing 1. Here, the shaft 13b and the guide groove 13c are provided auxiliary and are not necessarily provided. Further, in the above-described embodiment, the oil dashpot may be used as the detecting means instead of the solenoid 15, or a normal electrode solenoid having no coil spring 20 may be used.

4 and 5 show a structure in which auxiliary contacts are different from each other. Here, a contact drive plate 33 is projectingly provided under the trip plate 9a, and a pair of contacts 34 constituting the auxiliary contacts. , 35 are arranged so as to face each other in the direction orthogonal to the plane of FIG. A contact plate 36 provided with each contact 34, 35,
37 each have elasticity, and in the set state, the contact drive plate 33 presses one contact plate 36 from the outside so that both contacts 34, 35 are closed, and the trip plate 9a is moved upward. When the contact drive plate 33 moves over the stepped portion 37 provided on the contact plate 36, the pressing force acting on the contact plate 36 from the contact drive plate 33 is released and the contacts 34 and 35 are opened. I am trying to do so.

[Advantages of the Invention] As described above, the present invention provides an opening spring that biases the movable contact plate in the direction in which the breaking contact opens, and a movable contact plate that is pivotally supported at one end of the movable contact plate. And a trip plate whose both ends are swingably accommodated in a guide groove formed on the inner surface of the casing and running in a direction substantially orthogonal to the forward / backward direction of the armature of the overcurrent detection element. One end of the armature engages with the engagement hole provided in the trip plate with the spring force accumulated in the opening spring due to the pressure, and when the overcurrent passes through the main energization path, the engagement between the armature and the trip plate Since the closed contact is released and the breaking contact is opened by the spring force of the opening spring, both ends of the trip plate are housed in the guide grooves and slide, and the armature engages with the engaging hole provided in the trip plate. The spring force is applied to the opening spring by Since the trip board is held in the state where the electric charge is accumulated, it is possible to open and close the breaking contact instantaneously without adding any other member only by providing the trip board. That is, there is an advantage that the structure is simple and the number of constituent parts is small. Also, when the overcurrent flows, the breaking contact is opened only by the movement of the three parts of the armature, trip plate and movable contact plate, and the breaking is done after the amateur of the overcurrent detection element is pulled in by the overcurrent. This has the advantage that the response speed is high until the contacts open.

[Brief description of drawings]

1 and 2 are sectional views showing the structure and operation of one embodiment of the present invention, FIG. 3 is an exploded perspective view showing another embodiment of the present invention, and FIG. 4 is still another embodiment of the present invention. An example of a sectional view, FIG. 5 is a partially exploded perspective view of the same, FIG. 6 and FIG.
FIG. 8 is a sectional view showing the structure and operation of a conventional example, and FIG. 8 is an exploded perspective view of the same. 1 is a casing, 3 is a fixed contact, 4 is a movable contact plate, 5 is a movable contact, 9 is a trip plate, 10 is a guide groove, 11 is an opening spring, 14 is an engaging hole, 15 is a solenoid, 16 is an amateur, 30
Is a reset button and A is a breaking contact.

Claims (1)

[Claims] 1. A movable contact plate having a casing, a fixed contact fixed at a fixed position of the casing, a movable contact that constitutes a breaking contact together with the fixed contact, and a direction in which the breaking contact opens the movable contact plate. An opening spring that energizes, an overcurrent detection element that is inserted in series with the breaking contact in the main energizing path to draw in an amateur when an overcurrent passes, and the movable contact plate is pivotally supported at one end of the movable contact plate. In addition, a trip plate having both ends slidably accommodated in a guide groove formed on the inner surface of the casing and running in a direction substantially orthogonal to the advancing / retreating direction of the amateur, and one end abutting the movable contact plate and the other end Part is composed of a reset button that projects forward and backward from the casing as the movable contact plate moves, and the movable contact plate is pressed by pressing the reset button into the casing. When one end of the armature engages with the engaging hole provided in the trip plate with the spring force accumulated in the opening spring by the, the engagement between the armature and the trip plate when overcurrent passes through the main current path A circuit protector characterized by releasing the state and opening the breaking contact by the spring force of the opening spring.