JPS5951695B2 - Switch interlock device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improving the reliability of a switch interlock device.

A conventional device of this type is shown in FIG.

In the figure, 1 is the first switch, 2 is the first drive section, 3
4 is a second switch, and 4 is a second drive unit, which is operated by a freely rotatable lever 5 having one fulcrum. The drive shafts 6 and 7 of the second drive units 2 and 4 are linked.

Moreover, 8 and 9 are pressing springs for pressing the movable contact 10 against the fixed contact 11.

In this conventional device, the first. When the second switches 1, 2 are in the open state, a gap D is formed between both ends of the lever 5 and the end of the drive shaft 6.7.

The size of this gap D is 1/2 of the sum of the distance a between the contacts of each switch 1.3 and the pressing distance b of the pressing springs 8 and 9 (see Figure 2), that is, D = (a + b )/2 is required.

However, the first. If the second drive units 2 and 4 mistakenly perform the closing operation at the same time, the distance a between the contacts of the switches 1 and 3 will become closer by the distance of the gear 710.

This means that the withstand voltage between the contacts is approximately 100X (a
-D)/2%, which is dangerous.

Therefore, considering the above-mentioned risks, the distance between the contacts a
If you take a large value, for example, if a vacuum switch is used as a switch, the opening/closing distance will become larger.
A drawback arises in that the life of the bellows 12 shown in FIG. 3 is shortened.

Furthermore, when the distance a between the contacts is increased, the driving portion 2.4 becomes larger, which is a drawback.

The present invention has been made to eliminate these drawbacks, and is provided with two cams that are rotated by each switch, and when one switch is in the closed state, one cam is rotated by the other switch. By contacting the cam and preventing it from rotating, and by making sure that if both switches try to close, the cams will interfere with each other and neither will be able to rotate. Another object of the present invention is to provide a safe and long-life switch interlock device in which the movable contact does not stop between the opening point and the closing point, or both switches do not close.

Hereinafter, one embodiment of the present invention shown in FIG. 4 will be described.

In FIG. 4, 1 is the first switch, 2 is the first drive section, 3 is the second switch, 4 is the second drive section, and 6 is the movable contact 10 of the first switch 1. 7 is a shaft that is linked to the movable contact 10 of the second switch 3; 13 is a shaft whose driving side end is linked to the shaft 6, and rotates about a fulcrum 14; The first cam 15 is a second cam whose driving end is connected to the shaft 7 and rotates about a fulcrum 16.

And the above 1. The driven side end of the second cam 13.150 opposite to the driving side is connected to the first cam 13.150 when the pole is opened. It is located above the fulcrum 14.16 on the center line of the second switches 1, 3.

Next, the operation of the apparatus of this embodiment will be explained.

For example, when the first switch 1 is in the closed state, the first cam 1
3 is linked to the movable contact 10 and the shaft 6 and rotates as shown by the dotted line, so that the tip of the first cam 13 is positioned below the tip of the second cam 15 and second cam 1
The rotational movement of 5 is restricted.

Therefore, the second switch 3 will not be in the closed state while the first switch 1 is in the closed state.

Therefore, when the first switch 1 is in the closed state, in order to close the second switch, the first switch 1 must be opened once before the second switch 3 can be closed. Can not.

Moreover, in the opposite case to the above, that is, when the second switch 3 is in the closed state, the first switch 1 will not be in the closed state.

Also, 1st. If the second switches 1 and 3 try to change from the open state to the closed state at the same time, the first switch 1. Second cam 13, 15
Since the first and second cams start rotating at the same time, both cams restrict each other's movements, and as a result, the first and second cams start rotating at the same time. Both of the second switches 1 and 3 are stuck in the open state.

Here's the first one. By forming the fulcrums 14.16 of the second cams 13, 15 so that the drive shaft side of both cams 13.15 is short and the mating cam side is long, it is possible to prevent both switches from closing at the same time, and when one It is possible to sufficiently reduce the moving distance of the movable contact 10 when the other is in the closed state and the other is about to perform a closing operation, that is, when the closing operation is not allowed.

In this way, in this train system, two switches are never in the closed state at the same time, and by utilizing this effect, this train system can be operated at a low frequency such as shown in Fig. 5. It can be applied to the power factor adjustment capacitor opening/closing switch 17 of a balancer circuit in an induction furnace.

In the figure, 17 is a contactor with interlock, 18
are the condenser bag and the electric furnace body.

In this application example, malfunction of the switch due to erroneous signals can be mechanically prevented, improving the safety and reliability of the electrical circuit.

In addition, in the above application example, the case where the above-mentioned embodiment device was applied to a switch for a balancer circuit of a low frequency induction furnace was explained, but the present invention is not limited to this. It may also be used as a device.

As described above, according to the switch interlock device according to the present invention, two cams are provided which are rotated by each switch, and when one switch is in the closed state, one cam comes into contact with the other cam to prevent it from rotating,
In addition, when both switches try to close, both cams interfere with each other and become unable to rotate.This ensures a secure and highly reliable interlock, and prevents switch activation due to erroneous signals. Malfunctions can be mechanically prevented,
This has the effect of configuring an electrical circuit with a higher degree of safety.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing a conventional single-pole contactor with interlock, Figure 2 is a closed state diagram of the switch shown in Figure 1, and Figure 3 is a diagram showing the closed state of the switch shown in Figure 1.
FIG. 4 is a schematic diagram of a vacuum switch, FIG. 4 is a configuration diagram showing an embodiment of the present invention, and FIG. 5 is a diagram showing an example of application of the above embodiment to an electric circuit. In the figure, 1 is the first switch, 2 is the first drive unit, and 3 is the second
switch, 4 is the second drive part, 13 is the first cam, 15
is the second cam. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1 are arranged in parallel with each other and the first. The first drive unit is opened and closed by a second drive device. In a switch interlock device for preventing both second switches from being in a closed state, a first cam is rotatably disposed near the first drive device, and the first cam is rotatably disposed near the first drive device. The drive side end of the first cam is engaged with the movable part of the first drive device, and the driven side end of the first cam is engaged with the first cam on the center line of both switches when the first switch is opened. A second cam having the same configuration as the first cam is arranged symmetrically with the first cam in the vicinity of the second driving device. The first or second cam each prevents the other cam from rotating when one switch is in the closed state, and both cams interfere with each other when both switches try to close. An interlock device for a switch that is characterized by being immobilized.