JPH0222918Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a control device for controlling an air operator used in a power switch such as a disconnector or a grounding device.

BACKGROUND ART Power switches such as disconnectors and grounding devices that constitute opening devices installed in electrical stations such as substations are operated by air operating devices using operating cylinders driven by compressed air. Fig. 1 shows a conventionally used pneumatic operating device of this type, in which 1 is an operating cylinder;
This is a control cam attached to a shaft 3 provided at the tip of a piston rod (not shown). control cam 2
is slidably fitted into a long groove 5 provided in the frame 4, and is guided by the long groove and linearly displaced together with the piston rod. The shaft 3 is loosely fitted into a hole provided at the other end of a lever 7 whose one end is fixed to the main shaft 6, so that the displacement of the piston rod is converted via the lever 7 into rotational movement of the main shaft 6. The main shaft 6 is connected to a movable contact operating part of a disconnector or earthing device, and in this example, the switch is closed when the piston rod is extended to a first final operating position in which the control cam 2 is located at the left end as shown. Conversely, the switch opens when the piston rod is retracted to the second final operating position where the control cam 2 is located at the right end in the figure. Limit switches 8 and 9 are attached to the frame 4 so as to be located near both ends of the long groove 5, and when the piston rod is displaced to the first and second final operating positions, the control cam 2 controls the limit switches 8 and 9, respectively. These limit switches are operated by pushing up the actuators 8a and 9a. The limit switches 8 and 9 are connected to a control circuit (not shown), and the control circuit controls a solenoid valve for charging and discharging air into the operating cylinder 1.

Generally, the moving speed of the piston rod of an air actuator increases approximately in proportion to the moving distance, and reaches its maximum near the final position of operation, so the cam 2 pushes up the actuator 8a or 9a at the final position of operation, as in the conventional device described above. When the limit switch 8 or 9 is operated, a large impact force acts on the limit switch, resulting in damage to the switch and loosening of the limit switch fixing bolts.

The object of the present invention is to provide a limit switch that includes a cam that is linked to the displacement of an air operating device, an actuator that is operated by the cam, and a spring that returns the actuator, and that generates a detection signal at the final operating position of the air operating device. An object of the present invention is to prevent a large impact force from being applied to a limit switch in a control device for a pneumatic operating device of a power switchgear equipped with the following.

Therefore, in the present invention, a cam is provided so that the actuator of the limit switch is held displaced against the spring at positions other than the final operating position of the air operating device, and the actuator is returned by the spring at the final operating position. , the limit switch generates a detection signal of the final position of operation when the actuator returns.

In the conventional device, a cam is provided to drive the actuator of the limit switch against the spring at the final position where the piston rod of the air operating device moves at its highest speed, and the actuator is displaced against the spring. Since the detection signal was obtained depending on the state of the limit switch at the time of operation, a large impact force was applied to the limit switch, but as in the present invention, a cam was provided so that the actuator returned to its final position with a spring, and the actuator returned to its original position. If the detection signal is obtained based on the current state of the limit switch, a large impact force will not act on the limit switch. Therefore, it is possible to eliminate the risk of damage to the switch or loosening of the limit switch fixing bolts, etc., and the reliability of the control device can be improved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The control device of the present invention will be explained in detail below with reference to the illustrated embodiments.

FIG. 2 schematically shows the configuration of an embodiment of the present invention, in which 10 is an operating cylinder;
11 and 12 are regulating valves connected to both ends of the operating cylinder 10, and 13 and 14 are solenoid valves. The inlet sides of the electromagnetic valves 13 and 14 are connected to a compressed air source (not shown) via a strainer 15 and a three-way valve 16, and the outlet sides are connected to the operating cylinder 10 via regulating valves 11 and 12, respectively. Furthermore, 13c
and 14c indicate the coils of the electromagnetic valves 13 and 14, respectively.

The configuration of the fluid pressure circuit consisting of the operating cylinder 10 to the three-way valve 16 is known, and the coil 14c of the solenoid valve 14 is deenergized, the coil 13c of the solenoid valve 13 is energized, and the piston of the solenoid valve 13 is energized. When 13p is displaced downward as shown, the three-way valve 16, strainer 15, solenoid valve 13 and regulating valve 1
Compressed air is supplied to the chamber on the right side of the piston 10p of the operation cylinder 10 through the piston 10p. As a result, the piston 10p moves to the left in the drawing, and the piston rod 17 advances to the left. piston 10
With the displacement of p, the indoor air on the left side of the piston is discharged to the outside via the regulating valve 12 and the solenoid valve 14, but since the amount of discharged air is restricted by the regulating valve 12, the back pressure of the piston is gradually rises with the displacement, and the increase in the moving speed of the piston is suppressed. Next, the solenoid valve 13 is deenergized, and the solenoid valve 14
is excited, the solenoid valve 14 and the regulating valve 1
Piston 10p in operating cylinder 10 through 2
Compressed air is supplied to the chamber on the left side, the piston is displaced to the right, and the piston rod 17 is retreated.

A shaft 18 is attached to the tip of the piston rod 17, and this shaft 18 is loosely fitted into a dogleg-shaped elongated hole 21 provided at the other end of a lever 20 whose one end is fixed to the main operating shaft 19. Therefore, when the piston rod 17 is displaced to the left and right in the figure, the lever 20 is rotated clockwise and counterclockwise, respectively, and the main operating shaft 19 is thereby rotated clockwise and counterclockwise. An operating part of a movable contact of a power switch (not shown) is connected to the main operating shaft 19, and the shaft 18 is at the extreme end position A as shown in the drawing.
The closing operation of the switch is completed when the piston rod 17 advances to the first final operating position located at piston rod 17
The opening operation of the switch is completed when the switch moves backward.

In this embodiment, a manual operation shaft 22 is provided separately from the main operation shaft 19, and one end of a lever 23 is fixed to this manual operation shaft 22. A U-shaped groove 24 is provided at the other end of the lever 23, and a shaft 18 at the tip of the piston rod 17 is fitted into this groove 24. One end of a rod 26 is pivotally supported by a pin 25 near the end of the lever 23 on the manual operation shaft 22 side, and this rod 26 is slidable within a cylinder 28 that is pivotally supported by a pin 27 to a fixed frame (not shown). is mated to. The rod 26 and the cylinder 28 are urged in the direction of being separated from each other by a coil spring 29, and the rod 26, the cylinder 28, and the spring 29 constitute a holding device 30 that holds the switch in an open state or a closed state. There is. In FIG. 2, the lever 23 and its attached portion are shown above the lever 20 for convenience of explanation, but the lever 23 and its attached portion are actually aligned with the lever 20 in a direction perpendicular to the plane of the paper. It is set up like this. A manual handle (not shown) can be attached to the manual operation shaft 22, and by operating this handle and rotating the manual operation shaft 22, the lever 20 is rotated via the shaft 18, and the lever 20 is rotated as shown in the figure. It is now possible to manually operate switches that do not operate.

A control cam 31 is attached to the manual operation shaft 22, and limit switches 32 and 33 are arranged on both sides of the control cam at positions 180 degrees apart from each other. The limit switches 32 and 33 have actuators 32a and 33a and springs (not shown) that return these actuators to their original positions.The limit switches 32 and 33 have actuators 32a and 33a and springs (not shown) that return these actuators to their original positions. It is configured to assume different states. In this embodiment, the limit switch closes when the actuator is pushed against the spring, and opens when the actuator returns. The control cam 31 has a cylindrical first cam surface 31a and flat second and third cam surfaces 31b and 31c continuous to both ends of the cam surface 31a, and the piston rod 17 as shown in the figure. When is in the first final position of operation, the first cam surface 31a engages with the actuator 33a of the limit switch 33, displacing the actuator 33a against the spring, and the second cam surface 3
1b is the actuator 3 of the limit switch 32
This actuator 32a is returned to its original position opposite to the actuator 2a. Also, the shaft 18 is B as shown in the figure.
When the piston rod 17 is retracted to the second final operating position, the first cam surface 3
1a engages with actuator 32a to displace the actuator against the spring, and third cam surface 31c faces actuator 33a to return actuator 33a.

Referring to FIG. 3, the limit switch 3
An example of the configuration of a control circuit for controlling the electromagnetic valves 13 and 14 using valves 2 and 33 is shown. In the figure, P and N are terminals connected to the plus and minus terminals of a control DC power supply (not shown), respectively;
5 and 36 are relays, 35a and 35b are normally open and normally closed contacts of relay 35, 36a and 3
6b are normally open and normally closed contacts of the relay 36, respectively. Between the terminals PN are a series circuit of a contact 35a, a coil of a relay 35, a contact 36b and a limit switch 32, a contact 36a, a coil of a relay 36,
The contact 35b and the series circuit of the limit switch 33 are connected in parallel, and terminals C and T are drawn out from the connection point between the contact 35a and the coil of the relay 35 and the connection point between the contact 36a and the coil of the relay 36, respectively. Terminals C and T are terminals to which signals are given when operating the switch, and when a closing command is issued when the conditions for closing the switch are met, terminals C,
A voltage is applied between the terminals T and N, and when an opening command is issued when the conditions for opening the switch are met, a voltage is applied between the terminals T and N.

Assuming that the switch is now in the open state in the above embodiment, the piston rod 17 is retracted in FIG. be. If a closing command is issued here, the relay 35 is energized because voltage is applied between terminals C and N, and the contact 35a of this relay
is closed, and contact 35b is opened. When contact 35a closes, the voltage between terminals PN is applied to relay 35, so that this relay is self-held. The relay 35 has a normally open contact (not shown), and when the normally open contact is closed, the solenoid valve 13 shown in FIG. 2 is energized. Therefore, compressed air is supplied to the chamber on the right side of the piston 10p in the operating cylinder 10, and the piston 1
0p moves to the left. Along with this, lever 20
and 23 rotate clockwise, and the main operating shaft 19 and manual operating shaft 22 rotate clockwise. The rotation of the manual operation shaft 22 causes the first cam surface 31a of the control cam 31 to engage the actuator 33a, pushing the actuator against the force of the spring and closing the limit switch 33. limit switch 33
Even if the terminal is closed, the contact 35b is open, so even if a voltage is applied between the terminals T and N in this state, the relay 36 will not be excited. axis 1
8 is displaced to the illustrated position A and the circuit closing operation of the switch is completed, the second cam surface 3 of the control cam 31
1b opposes the actuator 32a and returns this actuator to open the limit switch 32. This deenergizes relay 35 and contacts 3
5a opens and contact 35b closes. At this time, a contact (not shown) that excites the coil 13c of the solenoid valve 13 also opens, and the solenoid valve 13 closes and the operating cylinder 1
Stop the supply of air into 0. Next, when an opening command is given, a voltage is applied between terminals T and N, so the relay 36 is energized, the contact 36a closes and the contact 36b opens, and the relay 36 is self-held by closing the contact 36a. . The relay 36 has a normally open contact (not shown) that opens and closes the excitation current of the coil 14c of the solenoid valve 14. When the relay 36 is energized, this normally open contact closes.
4 coils are energized. Therefore, air is supplied to the chamber on the left side of the piston in the operating cylinder 10, the piston 10p moves to the right, and the piston rod 17 retreats. This causes the levers 20 and 23 to rotate counterclockwise, and the main operating shaft 19 and manual operating shaft 22 to rotate counterclockwise. The rotation of the manual operating shaft 22 causes the first cam surface 31a of the control cam 31 to engage with the actuator 32a, thereby closing the limit switch 32. When the shaft 18 is displaced to the illustrated position B and the opening operation of the switch is completed, the third cam surface 31c of the control cam 31 opposes the actuator 33a to return the actuator to its original position, thereby opening the limit switch 33. This deenergizes the relay 36, deenergizes the coil of the solenoid valve 14, and closes the solenoid valve 14.

As in the above embodiment, if the actuator of the limit switch is released at the final position of the pneumatic actuator and returned to its original position by the built-in spring, a large impact will not be applied to the limit switch, which will prevent damage to the limit switch or damage to the limit switch. This can prevent the mounting bolts from loosening.

In the above embodiment, the limit switch opens when the actuator is released and returned by the spring, but depending on the configuration of the control circuit, the limit switch may be closed when the actuator returns. Further, in the above embodiment, the control cam 31 may be attached to the main operating shaft 19.

As described above, according to the present invention, the limit switch is operated and a detection signal is obtained by returning the actuator at the final operating position of the air operating device, thereby preventing impact from being applied to the limit switch at the final operating position. This has the advantage of preventing damage to the limit switch and loosening of the limit switch, thereby improving the reliability of the control device.

[Brief explanation of the drawing]

Figure 1 is a schematic front view showing the main parts of the conventional example;
The figure is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 3 is a connection diagram showing an example of a control circuit used in the embodiment of FIG. 2. 10...operation cylinder, 10p...piston,
17...Piston rod, 19...Main operating shaft, 2
0, 23...Lever, 22...Manual operation shaft, 31
...Control cam, 32...Limit switch, 32
a... Actuator, 33... Limit switch, 33a... Actuator.

Claims (1)

[Claims for Utility Model Registration] A cam that is linked to the displacement of the air operating device, an actuator that is operated by the cam, and a spring that returns the actuator to the final operating position of the air operating device. and a limit switch that generates a detection signal and stops charging the air operating device, the control device for an air operating device of a power switchgear includes: a limit switch that generates a detection signal of and stops charging the air operating device; The cam is provided so that the actuator is held in a displaced state against a spring and returned by the spring at the final operating position, and the limit switch generates a detection signal of the final operating position when the actuator returns. A control device for an air operator of a power switchgear, characterized in that it generates.