JPH0139175B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrical switches, and in particular to closed jacket type switches and circuit breakers equipped with a toggle type operating mechanism, in which all contacts are always actually open when the operating handle is in the OFF position. This increases safety by preventing the operating handle from moving to the OFF position in the event that the contact is welded, and by making it possible to confirm the OFF state by visually checking the position of the operating handle. be.

In general, a low-pressure air switch device is capable of switching and energizing a load current in an electric circuit, and is also capable of disconnecting the electric circuit when the switching device is turned "off."
Furthermore, this kind of switchgear is a low-pressure air circuit breaker equipped with a free trip mechanism that interrupts the electrical circuit in abnormal conditions such as overcurrent or short circuit, that is, air circuit breakers and molded case circuit breakers. A large current cutoff function is added. On the other hand, high-voltage circuit breakers generally have complicated arc extinguishing devices, and even when the circuit breaker is turned off,
Note that there is a connection between the input and output terminals in the form of stray capacitance, and it cannot be said that there is sufficient disconnection from the circuit voltage, so a disconnection means such as a disconnector is generally used in combination. Low-pressure air switchgears, especially low-pressure air circuit breakers, often handle large currents, so when turning on the circuit, it is necessary to use a method such as a spring, etc., to overcome the electromagnetic force and use a method that does not directly turn on the circuit manually. The most common method is to use mechanical force or electromagnetic force such as a solenoid. One of the methods of making the closing via a spring is a quick-on, quick-off method using a so-called toggle mechanism, which is generally widely applied to low-pressure air switches and especially molded circuit breakers.

On the other hand, similar switchgears, including this type of circuit breaker, do not allow direct visual inspection of the contact status of the contacts for safety in handling and compactness, so when the switch is on or off, the operating handle is When the circuit is turned off, the operating handle stops at the opposite position when turned to the off side, so you can tell whether the circuit is on or off based on the rest position of the operating handle. Separate. Also,
A molded circuit breaker with a free trip mechanism has a trip position. This type of switchgear generally has a sufficient distance between input and output in the off state,
Since it has sufficient withstand voltage performance and has few stray capacitance connections, this state has generally been regarded and treated as a disconnection state. Judging whether the circuit is on or off based on the position of the operating handle is inaccurate because it does not directly check the on or off state of the contact. For example, if the circuit breaker trips in an abnormal state while the operating handle is held in the on position, the circuit will be turned off, but since the operating handle is held in the on position, the problem is that the two do not match. However, the most important drawback is that this type of electrical switch opens and closes a movable contact device using a toggle mechanism consisting of an operating handle, an operating spring connected to the operating spring at one end, and a toggle link. In the unlikely event that the handle is welded in the ON state and cannot be separated, simply move the operating handle to the OFF side, and the operating spring will be expanded more than normal, causing the operating handle to move to the OFF position and stop. It is possible to determine that the electric switch is in the OFF state based on the open circuit position display on the operating handle that can be visually seen without the open circuit position display on the operating handle and the actual OFF state of the contact, If construction work or inspection/repair is performed on the load side of the electrical switch, there may be a risk of life-threatening accidents.

Therefore, the main object of the present invention is to eliminate the above-mentioned drawbacks, and to prevent the operating handle from being operated to the OFF position only when the contact is welded, and to ensure that the contact is not operated when the operating handle is in the OFF position. An object of the present invention is to provide an electric switch that can be guaranteed to be in an open state.

In summary, the present invention provides an opening/closing mechanism between an opening/closing lever and a movable contact device to prevent operation of the operating handle to the OFF position, only when the contact is welded, and in the process of shifting the operating handle to the OFF position. A blocking member is formed that engages or abuts between the lever and the movable contact device.

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

FIGS. 1 to 6 show one embodiment of the present invention.
The figure shows a three-pole circuit breaker equipped with a closing jacket made of an electrically insulating material. device 4, one end of the terminal conductor 5 of the fixed contact device 4 is connected to the connection terminal 3.
A fixed contact 6 is attached to the other end.

In the movable contact device 7, a movable contact 9 corresponding to the fixed contact 6 is attached to one end of a movable contact rod 8. In addition, the movable contact rod 8 is connected to the contact shaft 10.
It is rotatably supported by a contact holder 11 and connected to an intermediate connector 13 by a flexible conductor 12 from the lower end of the other end. The end of the contact holder 11 is connected to an insulating crossbar 27,
It rotates about the axis 28 as a fulcrum. Main current conductor 14
One end is connected to the intermediate connector 13, a bent heater portion 14a is formed in the middle, and the other end is connected to the connecting terminal 3' via a terminal conductor 15.

An operating handle 16 made of an insulator protrudes outward from the closure jacket as an operating mechanism for opening and closing the movable contactor 9 and a release tripping response device, and an opening/closing lever with a U-shaped cross section attached to the operating handle 16. 17 and an opening/closing lever shaft 18 that rotatably supports the lower end of the opening/closing lever 17 are connected to the fixed frame 1.
9, and the opening/closing operation is performed by moving the operating handle 16 using the opening/closing lever shaft 18 as a fulcrum. One end of the trip lever 20 is rotatably supported by a trip lever shaft 20b bridged over the fixed frame 19, and the other end 20a is formed to be engageable and releasable with the main hook 21. A pair of toggle links 22, 2
One end of the toggle link 22 of No. 3 is connected to a shaft 24 provided at the upper end of the center portion of the trip lever 20, and the other end is connected to a toggle link shaft 25, and one end of the toggle link 23 is a toggle link. The shaft 25 has a contact holder 11 at the other end.
and is connected to the movable contact rod 8 by a contact shaft 10.

The pair of operating springs 26 have one end mounted between the toggle link shaft 25 and the other end between the spring mounting piece 17a of the opening/closing lever 17, forming a toggle type opening/closing operating mechanism. The end of the contact holder 11 is connected to an insulating crossbar 27 that interlocks multiple poles, and the movable contact rod 8 is rotated to the open/close position by an operating mechanism about the axis 28 of the crossbar 27 as a fulcrum. It's getting old.

Further, the movable contact rod 8 is always biased in the direction of closing the circuit by the contact spring 29. A deformable cam 30 is integrally provided on the cross bar 27 so as to correspond to the notch 17b at the lower end of the opening/closing lever 17, and if the fixed contact 6 and the movable contact 9 are welded together, the opening/closing lever 17 Notch part 1
7b and the deformable cam 30 provided in the movable contactor device.
form a blocking member, and a part of the opening/closing lever 17 and a part of the movable contactor device 7 engage or abut each other, so that the operation handle 16 cannot be moved to the OFF position. .

The main hook 21 is rotatably supported by a hook pin 31 supported by the fixed frame 19 and has an upright plate-shaped portion, and the lower edge of the engagement piece 21a attached to the upper end of the main hook 21 and the trip lever 20 are connected to each other. It is adapted to be engaged with one end, and is always biased to rotate clockwise. The multi-pole interlocking trip shaft 32 has its axis rotatably supported by the frame 19, and is attached to the window hole 21b of the main hook 21.
It has a protruding piece 33 that is inserted into the engaging piece 21a and presses and engages the side surface of the engaging piece 21a. Further, a trip piece 34 is attached to the trip shaft 32 for each pole, and the free end of the trip piece 34 has a bimetal 3 integrally connected to the heater 14a at its lower end as a thermal tripping element of the overcurrent tripping device.
5 and the upper leg of the movable armature 36 of the electromagnetic device for instantaneous tripping are correspondingly provided. This movable iron piece 36 is attached to the frame 1 at an intermediate position.
9 is rotatably supported by a shaft 37, and its lower end corresponds to a fixed iron core 38 through which the main current conductor 14 passes. The fixed core 38 is attached to a fixed core support plate 39, and is supported by the mold base 1. A movable core return spring 41 is mounted between the upper part of the fixed core support plate 39 and a spring mounting piece 40 provided on the upper end leg of the movable core 36. is installed and biases the movable iron piece 36 clockwise.

The opening/closing operation of the circuit breaker constructed as described above according to the present invention will now be described.

To normally open the circuit from the closed state shown in Figure 2,
When the operating handle 16 is moved to the right off side,
The pair of toggle links 22 and 23 are bent deeply and the contact shaft 10 that connects the contact holder 11 and the movable contact rod 7 is pulled up.
The movable contact 9 separates from the fixed contact 6 using the fulcrum as the fulcrum, and enters the normal OFF state shown in FIG. 3. In this process from the on state to the off state,
When the line of action of the operating spring 26 that holds the toggle links 22, 23 of the toggle mechanism in an extended state moves beyond the dead center due to the movement of the opening/closing lever 17, the line of action begins to reverse so that the toggle links 22, 23 are bent. By pulling up the contact holder 11, the cross bar 27 rotates clockwise, allowing smooth opening operation without colliding with the notch 17b at the lower end of the opening/closing lever 17.

To close the circuit, move the operating handle 16 to the on side in the opposite direction to the above, and the toggle links 22, 2
3 is extended and the contact holder 11 and cross bar 27 are rotated in the closing direction to close the circuit. During this process, the deformable cam 30 provided integrally with the cross bar 27 begins to rotate counterclockwise. Since the opening/closing lever 17 is rotated counterclockwise, the closing operation is performed without the opening/closing lever 17 and the deformable cam 30 colliding with each other.

In addition, if an overload current flows in a closed circuit state, the bimetal 35 will bend due to overheating and the free end of the bimetal 35 will press the trip piece 34, or the electromagnetic device for instantaneous tripping will occur in the case of an overcurrent. The fixed iron piece 38 is excited and attracts the lower end of the movable iron piece 36 and is rotated counterclockwise about the shaft 37 as a fulcrum, and the upper end of the movable iron piece 36 presses the trip piece 34 and the trip shaft 3
2 is rotated counterclockwise, the protruding piece 33 that engages with the engaging piece 21a of the main hook 21 is disengaged, and the main hook 21 is rotated clockwise and inserted into the window hole 21b of the main hook 21. Projection piece 3 of trip shaft 32
At the same time as 3 slides deeply, the trip lever 20
The engagement between the tip 20a of the main hook 21 and the engagement piece 21a of the main hook 21 is released, the trip lever 20 is rotated counterclockwise, and the toggle links 22 and 23 are deeply bent into an inverted dogleg shape.
It is rotated clockwise to pull up 1, so
The fourth movable contact rod 8 moves together to separate the movable contact 9 from the fixed contact 6 and interrupt the circuit.
The trip state shown in the figure is reached. In this way, in the process of transitioning from the on state to the trip state, the crossbar 27
The deformable cam 30 integrated with the opening/closing lever 17 is formed to correspond to the notch 17b at the lower end of the opening/closing lever 17 and to perform a smooth tripping operation so as not to engage or collide with the movement of the opening/closing lever 17. has been done.

Next, a large current flows in the closed circuit state and the main hook 21
If a welding phenomenon occurs between the fixed contact 6 and the movable contact 9 and the movable contact 9 does not separate when the trip lever 20 is disengaged,
The movable contactor device 7 and the operating mechanism are held in the on-state position, and when the operating handle 16 and the operating mechanism are moved to the off side to turn it off for maintenance inspection etc., the operating spring 26 is expanded and the opening/closing lever 17 is moved. The deformable cam 30 is integrally provided with the crossbar 27 of the movable contactor device, and the notch 17b at the lower end of the opening/closing lever 17 is maintained in the on state during the rotation and movement toward the off position. 5 and 6, in which the opening/closing lever 17 is prevented from being moved further toward the OFF position, as shown by the solid line in FIGS.

As described above, this invention comprises at least a pair of contacts 6 and 9 that can be moved to open and close relative to each other, a movable contact rod 8 on which one contact 9 is mounted, a contact holder 11, a contact shaft 10, and a cross bar 27. a movable contact device 7 having a toggle link shaft 25 having one end connected to the movable contact device 7;
a pair of toggle links 22, 23 connected by;
An operation handle part 1 that is rotatably supported by a fixed frame 19 and whose one end is operated from the outside of the closed jacket.
6, and a toggle type opening/closing operation mechanism consisting of an operating spring 26 installed between the opening/closing lever 17 and the toggle link shaft 25. Only when welding occurs, the opening/closing lever 17 and the movable contact device 7 are engaged with each other so that the operating handle section 16 cannot be moved to the off position in the process of shifting the operating handle section 16 to the off position. Or a blocking member that abuts, for example, the opening/closing lever 17
Since it has a notch 17b provided in the movable contact device and a deformable cam 30 provided in the movable contact device, it has a conventional toggle opening/closing operation mechanism of this kind and has an operating handle protruding from the closure jacket. In electrical switches that determine the on/off position based on position, even if the contact is welded, the operating spring stretches more than normal to stop the operating handle from moving to the off position or reset position. However, according to the present invention, the operating handle can be turned off only in the case of welding of the contacts. If the operation handle is in the OFF position by preventing the switch from moving to the OFF position, the contactor can be opened safely and reliably, thereby preventing the danger of human life.In other cases, smooth opening and closing operations can be performed without any problems. It has the effect of being carried out.

Although the present invention has been described with respect to a circuit breaker as an embodiment, it may also be applied to an overcurrent response device of a circuit breaker,
Remove or disable the trip-free mechanism and turn it on;
It goes without saying that the application is also applicable to this type of switch where only the OFF operation is performed, and the opening/closing lever is designed to engage or abut only when the contacts are welded to prevent operation to the OFF position. Even if various modifications are made to the blocking members provided in correspondence with each other on the movable contact device 17 and the movable contact device 7, it will not depart from the scope of the present invention.

[Brief explanation of drawings]

1 to 6 show an embodiment of the electrical switch of the present invention. FIG. 1 is a plan view showing the closed circuit state with the cover removed, and FIGS. 2 to 5 are the same as in FIG. 1. These are side sectional views of the electrical switch taken along the line A-A'. Figure 2 shows the closed circuit state, Figure 3 shows the open circuit state, Figure 4 shows the tripped state, and Figure 5 shows the contactor in the tripped state. This is a diagram showing a state in which the operation handle is moved to the OFF direction due to welding and a trip operation is performed, and movement to the OFF position is blocked. Figure 6 is an enlarged explanatory view of the main part, and the solid line indicates the blocked state. , the dashed line indicates the normal off position. In the figure, 1: mold base, 2: mold cover, 4: fixed contact device, 6: fixed contact, 7: movable contact device, 9: movable contact, 11: contact holder, 16: operation handle, 17: Opening/closing lever, 1
9: Fixed frame, 20: Triple lever, 2
1: Main hook, 22, 23: Toggle link, 2
5: Toggle link shaft, 26: Operation spring, 2
7: Crossbar, 37: Deformed cam.

Claims (1)

[Claims] 1. A movable contact device having at least one pair of contacts movable relative to each other to open and close, a movable contact rod on which one of the contacts is mounted, a contact holder, a contact shaft and a crossbar, and the movable contact An opening/closing lever comprising a pair of toggle links whose one end is connected to the slave device and connected by a toggle link shaft, and an operating handle portion which is rotatably supported by a fixed frame and whose one end is operated from outside the closure jacket. and a toggle-type opening/closing operation mechanism consisting of an operating spring installed between the opening/closing lever and a toggle link shaft, and only when welding occurs between the pair of contacts, the operating handle portion A blocking member is provided that engages or collides between the opening/closing lever and the movable contact device so as to prevent the operating handle from being moved to the off position during the process of shifting the operating handle to the off position. electrical switch.