JPS6059835B2 - Control maintenance device for forward/reverse conversion rotating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control and maintenance device for forward/reverse converting rotating equipment, and in particular, it is driven by the electrical power of rotating equipment such as a motor from a single-phase or three-phase power supply, and is used to control equipment such as push button switches. The present invention relates to a control and maintenance device for forward/reverse converting rotary equipment, which is used by controlling the direction of rotation using an operating means, and is general-purpose for forward/reverse converting rotary equipment such as an electric hoist or a lateral moving trolley conveyor.

In general, a limit switch is sometimes used for the purpose of stopping the operation at a predetermined position for a forward/reverse converting rotary device such as an induction motor, particularly a three-phase induction motor, which is used for converting between forward and reverse directions.

Furthermore, hoisting machines such as motor blocks and lobe hoists are required to be equipped with limit switches.

However, in this equipment, the limit switch operates mechanically by detecting the position of the hanging tool at the upper and lower limits of winding, so if the power supply is connected to the opposite phase, the function will be affected. This has the disadvantage that it expires.

That is, if a limit switch is configured that has an independent stop function for each of the forward and reverse operating directions of the device, there may be a case where the limit switch becomes invalid when the phase of the power supply is reversed.

Such failure of the limit switch not only impairs the original function of the equipment used, but also may result in damage to the equipment and even danger to the user.

Therefore, a limit switch and a protection device for preventing and maintaining reverse phase operation have become essential elements for this type of equipment.

The most common type of reverse phase protection device is a relay type that electrically detects the phase order of the power supply and shuts off the operating circuit when the reverse phase is connected, but it is expensive. This method is not only relatively expensive, but also has drawbacks such as problems with the reliability of the electrical detection section. The present invention eliminates the various defects in the conventional devices as described above, and provides a forward/reverse conversion rotary device that has a so-called reverse phase protection function and can be maintained without loss of function even in other emergency situations. Its purpose is to provide a control and maintenance device for

Before describing embodiments of the present invention, the above-mentioned conventional system will be specifically described.

In other words, as related to the conventional method as described above,
The structure and operation of an electric chain hoist, which belongs to the conventional rotating equipment that uses forward and reverse rotation, will first be described in detail with reference to FIGS. 1 to 6.

FIG. 1 is a sectional view showing the general configuration of a conventional electric chain hoist. At the same time when voltage is applied to the electric motor 1, such as a three-phase motor for hoisting, the brake solenoid 2
is suctioned, the brake 3 is released, and the rotational force of the electric motor 1 is transferred to the first-stage pinion 5, first-stage gear 6, 2 in the deceleration mechanism section 4.
The speed is reduced by the stage pinion 7, second stage gear 8, third stage pinion 9, and third stage gear 10, and the reduced power is transmitted to the sprocket 11 and winds up the link chain 12 that meshes with the sprocket 11. Hanging tool (load block) 1
It is used to wind up or lower 3.

Each of the above-mentioned parts is supported by the frame A1, the frame Bl5, and the frame Cl6, and the frame Cl6 includes an electromagnetic switch 17, a limit switch 18, and a reverse phase prevention A relay 19 and the like are attached.

Furthermore, FIG. 2 is an electric circuit diagram of a control device developed as a conventional technique for the electric chain hoist having the above configuration.

As shown in the figure, for each phase R, S, and T of the three-phase power supply,
On the winding-side electromagnetic switch contact Mg of the electromagnetic switch 17 (hereinafter referred to as contact Mg).

) The limit switch contact L. on the hoisting side of the limit switch 18. S top. (hereinafter referred to as the contact L-S) and the electric motor 1 are connected in series. Furthermore, electromagnetic switch 1
Similarly, the lower side electromagnetic switch contact Mg lower (hereinafter referred to as the contact Mg lower) of the limit switch 18 and the lower limit switch contact L-S lower 2 (hereinafter referred to as the contact L-S lower) of the limit switch 18. These switches on the upper and lower sides are connected in parallel to the power supply, and among the three phases of the power supply, the R phase and the T phase are switched by an electromagnetic switch 17, and the motor rotation direction is changed to the upper or lower side. This has the effect of switching to the side. Assuming that the above-mentioned part is the main circuit C1, the operating circuit C2 provided to operate the main circuit C1 includes S1 on the hoisting side electromagnetic switch coil, on the hoisting side limit switch contact L-S of the limit switch 18, (
Hereinafter, it will be referred to as "on contact L-S".

) and the winding side push button switch PB are in the three-phase power supply, S
It is connected in series between the phase and T phase, and similarly, each element on the lower winding side, that is, the lower electromagnetic switch coil μS
2. Bottom side limit switch contact L-S (hereinafter,
It is called contact L-S bottom. ), and lower side push button switch P
B lower side is connected in parallel with the winding side. On the other hand, a negative phase prevention relay 19 is connected to the common line of the operation circuit C2.

Next, the operation of the electrical circuit of the electric chain hoist having the above connection configuration will be explained.

Now, if the top of the winding side push button switch PB is pressed, the top of the winding side electromagnetic switch coil S1 is excited and the top of the contact Mg is closed. As a result, terminal U of motor 1
, v, and w are connected to power supply phases R, S, and T, respectively, and the electric motor 1 rotates in the winding direction. Conversely, when the lower pushbutton switch PB is pressed, the lower electromagnetic switch coil S2 is excited, the lower contact Mg is closed, and the power supply is applied to the terminals U, v, and w of the motor 1. The phases T, S, and R are connected to each other, and the electric motor 1 rotates in the downward direction.

Further, at the same time as the electromagnetic switch 17 is turned on, voltage is applied to the brake solenoid 2 to release the brake 3.

The so-called limit switch 18 for hoisting and lowering limits mechanically cuts off the operating circuit C2 and the main circuit C1 when the hoisting device (load block) 13 of the electric chain hoist reaches the upper and lower limits. , is a protection switch that prevents overwinding.

Here, the configuration and operation of the limit switch 18 are as follows:
This will be explained with reference to FIGS. 3, 4, and 5.

First, FIG. 3 is a schematic cross-sectional view of the electric chain hoist shown in FIG. 1 taken along line I-1. That is, the link chain 12 passes through the limit guide A2O and the sprocket guide 21, meshes with the sprocket 11, and is wound up.
Then, it is discharged through the limit guide B22 and the limit spring A23.

A chain stopper 24 is fixed to the lower end of the link chain 12, and a limit spring B25 is mounted on the chain stopper 24 and the hanging tool 13, respectively.

In addition, limit guide A2O and limit guide B22
is continuous with the limit lever 26, and a limit rod 27 passes through the center of the limit lever 26, and the limit lever 26 can be rotated with the limit guides A2O and B22 using the limit rod 27 as a fulcrum. It is structured as follows.

In FIG. 4, which is also an external view of the limit switch 18 and a partially opened side view showing its general configuration, the limit rod 27 is connected to a switch unit 29 through a base 28, and the limit rod 27 is connected to a switch unit 29 through a base 28. The angle turning operation of the limit lever 26 shown in FIG. 3 is transmitted.

Further, a return spring 30 is installed inside the base 28, and this return spring 30 acts to apply a torque in the direction of always returning the limit rod 27 to the neutral position. Furthermore, the switch unit 29 is composed of three stages of stacked switch small units 29A, 29B, and 29C, and the switch small unit 29A connects the contacts L-S upper and L-S lower in FIG. 2 to the same 29B. is on the contact L-S in FIG. 29C is below the contact L-S in Figure 2.
It has a built-in FIG. 5 is a plan view of the small switch unit of the limit switch 18. That is, the limit rod 27 is connected to the cam 31, and the rotation angle of the cam 31 is converted into a linear motion of the roller 32, which opens and closes the movable contact 33 and the fixed contact 34.

The operating angle of the limit switch 18, that is, the opening/closing operating angle θi of its contacts is determined by the shape of the cam, which differs for each small switch unit. The operation of the limit switch 18 having the configuration as described above will be explained next. In addition, in FIG. 3, 01 is the rotation angle related to the first stage operating angle of the limit switch 18, θ
2 is a turning angle related to the second stage operation angle. now,
In Fig. 3, if the hoist 1 is operated in the hoisting direction,
3 reaches the upper limit, the limit guide A2O is pushed up via the limit spring B25, and the limit lever 26
turns around.

When the turning angle reaches θ1 in the figure, contacts L-S open in FIG. 2, interrupting the operating circuit C2, and opening contacts Mg to stop the motor 1. It is.

In the unlikely event that the upper contact Mg is welded, when the limit lever 26 further rotates and reaches the propagation angle θ2, the upper contact L-S opens and cuts off the main circuit C1.
This is to stop the electric motor 1.

The same operation is performed when the machine is operated in the downward direction.

As mentioned above, the operation of the limit switch 18 is as follows:
It is carried out mechanically, the direction of which depends on the direction of movement of the hanger 13, ie the direction of rotation of the electric motor 1.

Therefore, in an electric chain hoist with such a configuration, when the power supply is connected in opposite phases, for example, as shown in Fig. 2, among the three phases of the power supply, the R phase and T phase are connected in reverse. , when operating with the reverse phase connection shown in parentheses in Fig. 2, even if the upper pushbutton switch PB on the hoisting side is pressed, the motor 1
The direction of rotation is the lower winding side, and the limit switch 18 results in contacts L-S lower and L-S lower 2 being opened,
Even when the lower limit is reached, the circuit connected to the upper push button switch PB is not cut off, which is very dangerous as it may cause the limit switch 18 to fail and damage the equipment.

This means that the upper and lower winding side push button switches PB, PB
The same applies when pressing any of the buttons below. A reverse phase prevention relay 19 shown in FIG. 2 is provided to prevent such dangerous reverse phase operation.

This reverse phase prevention relay 19 is used to prevent the reverse phase from being generated by a three-phase power source. Connect the reverse phase by electrically detecting whether the power connection is positive or reverse, by using a rotating magnetic field, or by changing the phase of one of the three phases through a capacitor and using the potential difference that occurs between the phases. When the relay is opened, the operation circuit C2 is cut off, making it impossible to operate the equipment. It is.

Here, an example of the configuration and operating principle of the above-mentioned negative phase prevention relay 19 will be explained next with reference to FIG. 6.

That is, FIG. 6A is a diagram explaining the principle of the negative phase detection circuit.

Here, R, S, and T indicate each phase of the three-phase power supply as described above, and when the power supply voltage is applied in the phase order of R-S-T, it is considered a positive phase, and two of them are input. On the other hand, as shown in parentheses in the figure, for example, a state in which the R phase and the T phase are reversed is called a reversed phase.

Note that Cla represents a capacitor and R1 represents a resistor. With the wires connected as shown in Figure 6A, point A and R in the diagram
The voltage generated between the capacitor Cll and the resistor R
When the equivalent impedances of 1 are equal, the impedance is the highest when the phase is positive, and the lowest when the phase is negative, and the ratio is 4 to the negative phase 1.

This property is used to operate a relay and detect positive and negative phases. FIG. 6 shows an example of applying this to an actual circuit.

In the opening of Figure 6, the difference from A above is that the capacitor C
2al diode D and resistor R2 are inserted, and in the figure, 35 is a relay contact and RC is a relay coil.

In principle, the function can be achieved by simply using the voltage difference applied to the relay coil RC to turn the relay contact 35 ON during positive phase and OFF during negative phase, but in practice, it may be necessary to insert a diode or other element. There is a need to.

The purpose of inserting the diode D and the resistor R2 is to increase the return voltage of the relay and equivalently increase the voltage difference.

In other words, there is a significant difference between the operating voltage and the release voltage of a relay, and the release voltage is lower. Despite the reverse phase connection, the relay remains in its operating state, causing malfunction.

To prevent this, do not change the operating voltage of the relay too much.
A diode D and a resistor R2 are used for the purpose of increasing only the return voltage. That is, the operating voltage is determined by the voltage applied from the outside, regardless of the diode D1 and the resistor R2, while the release voltage is determined by the voltage applied to the relay coil RC.
Since it is determined by the change in the magnetic field due to the back electromotive force that occurs when the current decreases, it is possible to increase the return voltage by controlling the strength of the generated magnetic field using resistor R2. It can be done.

In addition, it is necessary to insert a capacitor C2a into the diode D for surge absorption. As mentioned above, for example, forward/reverse conversion rotating equipment using induction motors,
Particularly in heavy goods transportation machines such as electric chain hoists, a device for preventing reverse phase operation is essential as an important maintenance and safety component, along with a limit switch.

However, including the ones mentioned above, the conventional negative phase prevention relays as illustrated have the following drawbacks.

(1) The configuration of the electrical detection part is complicated.

That is, in order to cover the operating characteristics of the relay, various protection elements are added, and further protection of the elements becomes necessary, resulting in a vicious cycle. (2) The operating characteristics of the relay are unstable.

That is, since it has movable parts, protection against external vibrations and shocks is required.

(3) There is a problem with reliability.

That is, in addition to a decrease in reliability due to the complexity of its constituent factors, there is also a problem with the service life due to the relay having a movable mechanism.

(4) Since this method makes it impossible to operate the device when it is connected in reverse phase, there are cases where the user misunderstands that the device is malfunctioning.

(5) Although reverse-phase connections of the power supply are detected, incorrect connections of internal wiring, such as motor terminals, cannot be detected.

(6) Not applicable to single-phase power supply circuits.

As described above, the present invention eliminates the drawbacks of the prior art as described above, and provides control and maintenance in forward/reverse conversion rotary equipment using a limit switch that has a simple configuration and has a highly reliable mechanical reverse phase prevention function. Its purpose is to provide equipment. In addition, as detailed in the conventional example above, in electric chain hoists, for example, reverse phase connection becomes a problem even though the operation circuit on the hoisting side is operating. The problem lies in the fact that the direction of the electrical circuit and mechanical operation do not match, as shown in the example above when the machine rotates downward.

However, the drawback of the conventional reverse phase prevention device can be said to be that it uses a method of electrically detecting only the connection of the power supply, regardless of mechanical operation. In this respect, the present invention adopts a method in which the detection of the reverse phase connection is performed not electrically, but by mechanical operation such as an electric chain hoist, which is a rotating device for forward/reverse conversion. In addition to making it more reliable, we have developed a new method to equip the limit switch with a reverse phase prevention function, which performs the same function as the conventional limit switch itself, but also has a reverse phase prevention function. It can be said that there are important points.

The configuration of the control maintenance device for a forward/reverse converting rotary device according to the present invention is such that the rotation direction of the forward/reverse converting rotary device is controlled by the operation and the main circuit, and the limit provided for the forward/reverse converting rotation operation. A first-stage limit switch section that interrupts a switch provided in the operation circuit so as to control the forward/reverse rotation direction of the forward/reverse converting rotary device; and an electric motor that also rotates the forward/reverse converting rotary device. and a second stage limit switch section provided in the main circuit according to the above and configured to cut off the forward/reverse operation common power supply circuit, and the second stage limit switch section has a convex part. A driven cam is formed by combining a driven cam with a convex part and a concave part having a gap in the rotational direction, and is integrally formed with the main driving cam through the gradual rotation of the driven cam and the engagement of the concave and convex parts. When the driven cam is rotated to an angle of and is formed so that the contact piece on the driven cam can be quickly opened and closed independently of the rotation of the driving cam, and the operating range of the limit switch section related to the first and second stages is limited. An operating element such as a lever that is mechanically divided and connected to the drive mechanism of the main drive cam of a limit switch is placed between two movable pins that are tensioned by an elastic body such as a tension spring, and the operating element is The force that moves the operating element comes into contact with the pin before it reaches the operating point of the limit switch section related to the second stage, and its operation is restricted, and the operation of the limit switch section related to the first stage becomes invalid. The structure is formed so that the pin is pushed up by overcoming the tension of the pin to operate the second-stage limit switch section, so that only the limit switch section related to the first stage operates during normal operation of the controlled device. This is what I did.

Next, one embodiment of the present invention will be described with reference to FIGS. 7 to 16.

FIG. 7 shows the configuration of a control and maintenance device for an electric chain hoist, which is an embodiment of the present invention, and is also an electrical circuit diagram thereof, and FIG. 8 shows the configuration of the control and maintenance device described above. 18A is a limit switch used for forward/reverse conversion operation in the electric chain hoist; C4 is the aforementioned main circuit, and C4 is the operating circuit.

Therefore, in the limit switch 18A, the upper limit switch contact L-S on the hoisting side and the lower limit switch contact L-S on the lower hoisting side are provided in the operation circuit C so as to control the forward and reverse rotation directions. Electromagnetic switch 17
This is related to the first stage limit switch section that is designed to cut off the power.

In addition, the limit switch contact L-S2 related to the second stage of the limit switch 18A is provided in the main circuit C3 related to the electric motor 1 that rotates the electric chain hoist, and interrupts the common power supply circuit for forward and reverse operation. This relates to the second-stage limit switch section, which is configured to do so.

In addition, 48 is a reset button, K1 is a device main body cover, and K2 is an actuator.

That is, in the electric circuit shown in the above-described electric chain hoist circuit shown in FIG. .
), and this contact L-S2 is arranged on the common line above the contact Mg and below the Mg, and between the electric motor 1, that is, the electric motor! The common power supply circuit is cut off during forward and reverse rotation. In the above circuit configuration, the limit switch 18
A operates as described below.

That is, when the hoist 13 reaches the upper hoisting limit, the upper contact L-S opens, and when the hoist 13 reaches the lower limit, the lower contact L-S opens. There is no difference.

However, when the reverse phase is connected, for example, when the upper hoisting pushbutton switch PB is pressed and the motor 1 rotates in the lowering direction, even if the hoisting tool 13 reaches the lowering limit and the contact L-S lower opens. Since it is the operating circuit on the hoisting side that is operating, the circuit of the electric motor 1 is not interrupted, and the electric motor 1 continues to rotate.

At this time, as in the case described above, the limit lever 2
When the motor 6 turns beyond a certain angle, the contact L-S2 is opened as described later, so that the power to the motor 1 is cut off and stopped, and the brake solenoid 2 is turned off. The circuit is also cut off and the brake operates to hold the load.

This relationship holds true even when the bottom push button switch PB on the winding lower side is pressed in reverse phase connection.

That is, press the lower part of the PB to perform the hoisting operation, and lift the hoist 1.
3 reaches the upper winding limit, the contact L-S opens, but the motor 1 continues to rotate, and when it reaches a certain position, the contact L-S opens.
S2 is opened, the electric motor 1 is stopped, and the brake is operated to hold the load. By satisfying the basic operation as described above, by using the limit switch 18A, its function will not be lost no matter what state the power supply is connected to, and the existing negative phase prevention relay 19 etc. will not be required. However, it is possible to obtain a control maintenance device with performance that is not limited to the above. Furthermore, in the device according to the present invention, in addition to the configuration corresponding to the above basic operation, the following first
- Among the third functions, at least those related to the first and second functions are added, thereby providing a more effective limit switch configuration.

That is, firstly, the limit switch 1 in the second stage
The operation of the 8A is based on a three-contact simultaneous disconnection mechanism.

The reason for this is that when contact L-S2 is in slow motion interruption, if the contact gap is small and the contact is stopped, it may cause problems such as contact melting due to arcing. This is because if the motor 1 is stopped in the cut-off state, the motor 1 will be in a single-phase operating state and may be burnt out.

For the above reasons, the limit switch 18A according to the present invention
The second stage contact is a three-contact simultaneous disconnection mechanism. Second, between the first stage contact L-S upper and L-S lower 1 and the second stage contact L-S2, operational separation is provided as described above, and the normal In normal usage conditions such as positive phase connection, the contact L-S2 is configured not to operate.

The reason for this is that when the contact L-S2 operates, the power supply circuit of the motor 1 is cut off, so no matter how many times you press the upper and lower pushbutton switches PB on the hoisting and hoisting sides, the motor 1 does not operate and becomes inoperable. Because it will be. Therefore, measures have been taken to prevent contact L-S2 from operating under normal usage conditions. Thirdly, if the contact L-S2 of the second-stage limit switch 18A operates under abnormal usage conditions and the device becomes inoperable, the contact L-S2 is configured to be able to be reset manually. .

The reason for this is that hoisting machines such as electric chain hoists require a function that allows the load to be unloaded even after an emergency stop, as it is especially dangerous for the load to stop and hang in the air. It's for a reason.

By adding the three functions described above to the basic functions, the present invention becomes even more effective. Next, a specific configuration for operating the embodiment device of the present invention, that is, the limit switch related thereto, as described above will be explained with reference to the respective figures.

FIG. 9 is a sectional view showing the configuration of a switch mechanism in a limit switch in an embodiment of the present invention.

Note that the mechanical part of the switch replaces the switch unit 29 of the limit switch shown in FIG. 4, and the rest is the same, so illustration is omitted. In addition, Fig. 10 shows ■-■ in Fig. 9.
FIG. 11 is a cross-sectional view taken along the line ■-■ in FIG. 9.

Of the components described below, the frame, the contact piece components including contacts, the spring, the E-ring, etc. are made of metal, and the rest are made of, for example, synthetic resin. In FIGS. 9 to 11, 36 is a frame, 37
is the main drive cam, 37-1 is the shaft thereof, 37-2 is the convex part of the main drive cam 37, 38 is the lid, 39 is the driven cam, 39-1, 39-2 are the recesses of the driven cam 39 and a convex part,
39-3 is a slope, 40 is a contact piece stand Al4l, movable contact piece Al4l-1 is a slider, 42 is a movable contact piece B, 42
-1 is a slider, 43 is a screw Al44 is a contact piece base Bl
45 is a fixed contact piece, 46 is a reset lever, 4
7 is a spring, 48 is a reset button, 49 is an E ring, 50 is an adjustment screw, 51 is a cover, 52
is screw B.

That is, the main drive cam 37 is rotatably held at one end by the frame 36, and the other end is rotatably held by a lid 38 attached to the frame 36.

A driven cam 39 is incorporated into the shaft 37-1 of the driven cam 37.

The movable contact pieces A4 each have elasticity on the contact piece base A4O.
l and movable contact piece B42 are fixed by screw A43, and fixed contact piece 45 is also fixed by screw A43 to contact piece base B44.
and are each fixed to the frame 36.

In addition, movable contact piece A4l. Slider 4 is placed in the middle of the length direction.
1-1, and the slider 41-1 is strongly pressed against the main drive cam 37 by the elastic force of the movable contact piece A4l.

Further, a slider 41-1 is attached to the convex peripheral portion 37-3 of the main driving cam 37.
If they are in contact with each other, the movable contact piece A4l is in contact with the fixed contact piece 45 at each tip, but the convex peripheral portion 37-3 and the slider 41-1 are not in contact with each other. If so, do not contact.

The movable contact piece B42 also has a slider 42-1 in the middle, and the slider 42-1 is strongly pressed against the driven cam 39 by the elastic force of the movable contact piece B42.

Further, when the slider 42-1 is in contact with the convex portion 39-2 of the driven cam 39, the movable contact piece B42
5 and the respective tips 7 are in contact with each other, but the convex portion 3
If the slider 9-2 and the slider 42-1 are not in contact with each other, they do not contact each other. The reset lever 46 incorporates a spring 47, is inserted into the contact piece base B44 so as to be vertically slidable, and is attached to the frame 3.
6 and is combined with a reset button 48 and an E-ring (49).

The adjustment screw 50 is screwed into the contact piece base B44 and comes into contact with the fixed contact piece 45. The cover 51 is attached to the frame 36 with screws B.
52, and covers the entire switch mechanism section. Therefore, in the switch mechanism section having the above configuration, the part shown in FIG. 10 is the contact L shown in FIG.
The portions corresponding to -S upper and L-S lower and shown in FIG. 11 constitute contact L-S2 (three contacts).

Further, all three movable contact pieces B42 constituting the contact L-S2 are connected by a slider 42-1 and are integrated.

Now, the operation of the switch mechanism described above will be explained below.

In FIG. 10 mentioned above, the main drive cam 37 is
For example, in the case of slow rotation in the counterclockwise direction, the slider 41-1 of the movable contact piece A4l that is in contact with the convex peripheral part 37-3 of the main driving cam 37 is moved by its elastic force to the convex peripheral part 37-3. 3, the movable contact piece A4l and the fixed contact piece 45 release their respective tips from the contact state.

Further, when the main driving cam 37 rotates clockwise, the contact piece performs an opening operation at the other convex peripheral portion that is symmetrical therewith.

That is, a similar opening operation is performed by the other convex circumferential portion 37-3, which is in a symmetrical relationship with the convex circumferential portion 37-3 of the above-mentioned driving cam 37 at a different axial position. As a result, on the contact L-S in the circuit shown in FIG.
The following operations will be performed under LS.

Next, as shown in FIGS. 12 to 15, limit switch 18
Contact L-S which is the limit switch part related to the second stage of A
The operation of the parts constituting part 2 will be explained.

12 to 15 are enlarged views of the arm, contact piece, and slider shown in FIG. 11.

FIG. 12 shows a state in which the main drive cam 37 is in the neutral position. At this time, the main drive cam 37 having the width W
The convex portion 37-2 of the driven cam 39 and the concave portion 3 of the driven cam 39 having a width V
9-1 are in contact with each other with a gap of ■-W, and the centers of the convex portion 39-2 of the driven cam 39 and the slider 42-1 of the movable contact piece B42 are aligned. ing. Next, the first
As shown in FIG. 3, when the driving cam 37 rotates counterclockwise by a certain angle, the respective side surfaces of the convex portion 37-2 of the driving cam 37 and the concave portion 39-1 of the driven cam 39 abut.

While the main drive cam 37 rotates up to this point, the convex peripheral portion 37- of the main drive cam 37 is released so that the first stage contacts corresponding to the contacts L-S upper and L-S lower are released as explained earlier. 3 and adjust the operation using the adjusting screw 50. Now, as the driving cam 37 further rotates, the movement of the driving cam 37 is transmitted to the driven cam 39,
The position shown in FIG. 14 is reached.

If the driving cam 37 continues to rotate beyond this position,
The slider 42-1 slides down along the slope 39-3 of the driven cam 39. At this time, the driven cam 39 and the main driving cam 3
7 has the gap ■-W as described above, the slider 42-1 slides down the slope 39-3 of the driven cam 39 at once, and turns the driven cam 39 to form the position shown in FIG. Reach position and stop. Due to this operating mode,
The contact between the ends of the movable contact piece B42 and the fixed contact piece 45 is quickly released.

That is, the contact L-S2 shown in the circuit of FIG. 7 is in an open state. By using the limit switch 18A having the switch mechanism configured and operated as described above, the device according to the present invention operates in two stages, and the first stage is for winding up and lowering. Contact L-S that opens in slow motion in each direction
It is possible to expect an overall configuration in which the upper, L-S and lower contacts are operated, and the second stage is a contact L-S2 having a three-contact simultaneous cut-off function. After the contact L-S2 is opened, the contact can be manually reset by pulling the reset button 48 shown in FIG. In connection with this configuration, in the device shown in FIG. 8, a mounting hole is provided in the device main body cover K1 at a position opposite to the reset button 48, so that the reset lever 46 described earlier can be operated. The actuator K2 used for this purpose is made to protrude outside the main body of the device to form a so-called manual input/reset operation section. Furthermore, in this embodiment, under normal usage conditions, the limit switch 1
The contact L-S2 related to the second stage of 8A is made not to operate, and its specific configuration and operation are as follows.
The following will be explained with reference to FIGS. 16 and 17.

First, FIG. 16 shows the structure of the conventional electric chain lock shown in FIG.
Relating to operating elements such as levers combined with the drive mechanism of No. 7,
A pin 54 extends one end of the limit lever 26 and engages with an elongated hole 53 provided in the frame Bl5 and frame Al4.
A structure is added in which the tension is constantly pulled by a tension spring 55.

FIG. 17 is a right side view of FIG. 16, and as shown in FIG. 17, retaining rings 56 are attached to grooves at both ends of the pin 54 to prevent it from coming off.

1. That is, with the above configuration, when the hoist 13 reaches the hoisting and hoisting limits, the limit lever 26 rotates by θ1 and the contact point L
When -S upper or L-S lower opens, the end of the limit lever 26 collides with the pin 54, pushes the pin 54, and tries to extend the tension spring 55. At this time, by making the tension of the tension spring 55 larger than that of the limit springs A23 and B25, the movement of the limit switch 18A after opening is absorbed by the deflection of the limit springs A23 and B25, and the 5 limit lever 26 This means that it is not possible to perform an angle rotation of 01 or more. Therefore, under normal usage conditions, the operation of the device is stopped only by the operation of the contacts L-S upper and L-S lower, and the contact L-S2 related to the second stage does not operate.

If the contacts L-S upper and L-S lower become ineffective due to reverse phase connection, etc., the electric motor 1 will continue to rotate, and the limit springs A23 and B25 will come into close contact with each other, so that the limit lever 26 will finally be pulled. The angle is turned by overcoming the tension of the spring 55, and the operating angle θ2 of the contact L-S2 related to the second stage is reached and stopped.

The embodiment of the present invention having the configuration and operation described above has the following effects in summary.

(1) According to this configuration, the detection of reverse phase operation and its protection are performed mechanically using a limit switch,
No electrical detection part such as a reverse phase prevention relay is required. (2) Since it does not have an electrical detection section, there is no fear of malfunction due to disturbances such as power supply voltage, ambient temperature, impact vibration, etc., and the device is functionally stable.

(3) A limit switch that conventionally required a three-stage switch unit can be simplified to a two-stage configuration, and reliability can be improved by simplifying the constituent factors. (4) The device can be operated even with a reverse phase connection, and there is no risk of the user misinterpreting it as a malfunction. (5) It is possible to deal with not only the reverse phase connection of the power supply but also the reverse phase state due to internal connection errors such as electromagnetic switches and motor terminals.

(6) Applicable not only to three-phase power supply circuits but also to single-phase power supply circuits.

(7) The structure is such that the emergency circuit does not operate under normal usage conditions, making it highly functional as a safety switch.

(8) Since it uses a three-contact simultaneous disconnection mechanism, there is no risk of arcing or single-phase operation.

(9) The reset button allows easy manual return and recovery to normal state.

[Phase] It has an emergency stop function not only for reverse phase use but also for electromagnetic switch welding.

Here, what is shown in FIG. 18 is an application example in a single-phase power supply circuit related to the above (6).

In the figure, parts with the same symbols as in Fig. 7 are equivalent functional parts, Wm is the motor main winding, W3 is the motor starting winding, and C
33 is a starting capacitor, and CS is a centrifugal force switch.

In the same circuit as above, when the upper push button switch PB on the hoisting side is pressed, the upper electromagnetic switch S1 on the hoisting side is excited, the upper contact Mg is closed, and the motor main winding Wm and the starting winding Ws are energized to start the motor.

When the rotational speed increases and reaches a certain point, the centrifugal force switch CS opens to cut off the starting circuit, and the motor operates only with the main winding circuit.Also, press the lower pushbutton switch PB on the winding lower side. , the lower electromagnetic switch coil S2 on the lower winding side is excited, and the contact M
g lower circuit is closed and the motor main winding and starting winding Wm
, Ws are energized and started.

When the rotational speed increases and reaches a certain point, the centrifugal force switch CS opens and cuts off the starting circuit, and the system operates using only the main winding. This can be done by switching the terminals of the winding Wm. Therefore, the operation of contacts L-S upper and L-S lower controls the interruption of the operating circuit in the same way as in the three-phase case, and the operation of contact L-S2 also controls the interruption of the main circuit. It is something.

In the above-mentioned embodiments of the present invention, the electric chain hoist for hoisting and hoisting has been described. It can equally be used for mobile trolley conveyors, and in short, it is useful as a control and maintenance device for a wide range of forward/reverse converting rotating equipment. It is equally effective not only for phase power supplies but also for those using single-phase power supplies.

Taking all of the above into account, the present invention has a simple structure and high reliability, and can be said to be an outstanding invention.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view showing a general configuration example of a conventional electric chain hoist, Fig. 2 is an electric circuit diagram relating to a general control method of a conventional electric chain hoist, and Fig. 3 is a schematic cross-sectional view showing a general configuration example of a conventional electric chain hoist. 1
4 is a schematic sectional view taken along line I-1 in the figure, FIG. 4 is a partially opened side view showing the general configuration of a limit switch used in a conventional electric chain hoist, and FIG. FIG. 6A is a plan view showing the configuration of a small switch unit in the limit switch shown in the figure. FIG. 7 is an electric circuit diagram showing an embodiment of the apparatus of the present invention and used in an electric chain hoist, FIG. 8 is a schematic cross-sectional view of the electric chain hoist, and FIG. 10 and 11 are cross-sectional views of the limit switch in the above embodiment, respectively.
The cross-sectional views along the -■ line and the ■-■ line, Figures 12 to 15,
FIG. 11 is an explanatory diagram of the operation of the driving cam and the driven cam, FIG. 16 is a sectional view showing the configuration for regulating the operation of the limit switch in the embodiment device of the present invention, and FIG. 17 is approximately on the right side of FIG. 16. The top view and FIG. 18 are circuit diagrams showing an example of application to a single-phase power supply circuit. 1... Electric motor, 17... Electromagnetic switch, Mg upper...
- Hoisting side electromagnetic switch contact, Mg bottom... Hoisting bottom side electromagnetic switch contact, 18A... Limit switch, L●S upper 1... Hoisting bottom side limit switch contact, L-S bottom, hoisting bottom side , Mituto switch contact L/S2... limit switch contact related to the second stage, S1... upper winding side electromagnetic switch coil, S2... lower winding side electromagnetic switch coil, PB upper... winding upper side push button switch, PB Bottom: Lower side push button switch, C3: Main circuit, C4: Operation circuit, 37
... Main drive cam, 37-2... Convex part of main drive cam, 37
-3... Convex peripheral part, 39... Followed cam, 39-1...
- Concave portion of the driven cam, 39-2... Convex portion of the driven cam, 3
9-3... Slope of driven cam, 40... Contact piece stand Al4
l...Movable contact piece Al4l-1...Slider, 42...
・Movable contact piece Bl42-1...slider, 44... contact piece base B, 45... fixed contact piece, 46... reset lever, 48... reset button, 53... length Hole, 54...
Pin, 55... tension spring, 56... retaining ring.

Claims (1)

[Scope of Claims] 1. In a device in which the rotation direction of a forward/reverse converting rotary device is controlled by operation and a main circuit, a limit switch used for forward/reverse rotation converting operation is controlled by a limit switch in the forward/reverse converting rotating device. A first-stage limit switch section that interrupts a switch provided in the operation circuit to control the forward and reverse rotation direction, and also provided in the main circuit related to the electric motor that rotates the forward and reverse conversion rotating device, and a second-stage limit switch section configured to cut off the forward/reverse operation common power supply circuit, and the second-stage limit switch section is connected to the drive cam having the convex section and the convex section. A driven cam is formed by combining a driven cam having a recessed part with a gap in the rotation direction, and the driven cam is rotated to a predetermined angle together with the driven cam through the engagement of the concave and convex part by slow rotation of the driven cam. At this time, the slider integrated with the plurality of electric contacts slides along the sloped portion protruding from the driven cam and rotates the driven cam, thereby causing the rotation of the driving cam to coincide with the rotation of the driving cam. The driving cam of the limit switch is formed so that the driven cam can independently quickly open and release the contact piece, and mechanically divides the operating range of the limit switch section related to the first and second stages. An operating element such as a lever connected to a mechanism is placed between two movable pins that are tensioned by an elastic body such as a tension spring, and the operating element reaches the operating point of the limit switch section related to the second stage. Only when the operation of the limit switch section related to the first stage is disabled due to the previous contact with the pin and its operation is disabled, the force that moves the operating element overcomes the tension of the pin and pushes the pin up, causing the second stage to move. Control maintenance in forward/reverse converting rotary equipment, characterized in that the second limit switch part is formed to operate, and during normal operation of the controlled equipment, only the limit switch part related to the first stage is operated. Device. 2. A control maintenance device for a forward/reverse converting rotary device according to claim 1, which is configured to be manually reset after the second stage limit switch section operates. 3 In claim 1, manual return is possible by engaging the tip of the reset lever and the contact point of the limit switch section related to the second stage and operating a knob integrated with the reset lever. A control maintenance device for forward/reverse conversion rotating equipment.