JPH11209081A - Electric hoist - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the overheat of a motor, issue an alarm for advance notice of overheat, prompt a user for countermeasures and avoid the inconvenience of the motor to be stopped suddenly in work. SOLUTION: An electric winder includes an operator 8, a motor 1, a speed reducing mechanism 5, a braking mechanism 4, a control means to control these, a temperature detecting means 40 for the motor and an alarming means 17. The control means monitors the temperature of the motor 1 with the temperature detecting means 40 to issue an alarm for advance notice with the alarming means 17 when it approaches to a safely limit temperature and stop the motor 1 when it arrives at the temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric hoist for lifting and lowering a suspended load by electric power.

[0002]

2. Description of the Related Art As an example of an electric hoist having a function of preventing overload of a motor, there is a motor overload detecting device for a hoist disclosed in Japanese Patent Laid-Open No. 5-229785. This is because the motor voltage detection means and the motor temperature detector calculate the motor speed when the rated load is hoisted at the voltage and temperature, and the motor speed is detected by the motor speed detection means. If the actual rotation speed is lower than the calculated rotation speed as compared with the actual rotation speed, it is determined that an overload has occurred, and a signal indicating the detection of the overload is output.

[0003] Further, in a general electric hoist, when the temperature of the motor reaches a certain value due to an overload or a short repetition of turning on and off a switch, the current of the motor is cut off to prevent overheating of the motor. Equipped with a temperature protector to prevent.

[0004]

According to the above prior art,
Since the overload is detected by comparing the number of rotations of the motor with a reference value, and the reference value is calculated in consideration of the motor temperature,
An overload can be determined without being affected by fluctuations in the motor temperature. In the case of overload, the motor is stopped, so that overheating of the motor due to the overload and damage to the hoist can be prevented. However, no consideration has been given to preventing overheating of the motor due to continuing an inching operation in which the switch is turned on and off little by little.

[0005] By repeatedly turning on and off the switch at intervals of about 0.3 seconds, the inching operation of gradually raising and lowering is frequently performed in the electric hoist. Since a large current flows when the motor is started, the temperature of the motor rises, and if the motor is continued for a long time, the motor will overheat.

Further, in the method of preventing overheating of the motor by the temperature protector, no consideration is given to the disadvantage that the temperature protector suddenly operates without notice and takes a long time to recover after the operation. If the temperature protector is activated during work, the motor will stop suddenly regardless of the state of the suspended load, and the user will stop working until the motor cools and the temperature protector returns due to the heat capacity of the motor. Inevitably, even if the suspended load is suspended, it is not possible to take measures such as temporarily lowering the suspended load.

An object of the present invention is to prevent overheating of a motor,
Another object of the present invention is to provide an electric hoist that generates a warning notice to a user before overheating and urges the user to cope with the problem and does not cause inconvenience such as work interruption due to sudden stoppage of the motor.

[0008]

SUMMARY OF THE INVENTION An electric hoist according to the present invention comprises an operating device for a user to perform operations of raising, lowering and stopping, a motor, and a reduction mechanism for reducing the rotation of the motor.
And a brake mechanism for stopping rotation of the speed reduction mechanism, control means for controlling the motor and the brake mechanism based on operation information from the operation device, and detecting a temperature of the motor and outputting the detected temperature to the control means. The electric hoist main body comprises temperature detecting means, a rope which is hoisted and lowered by the speed reduction mechanism, and a hanger attached to the lower end of the rope to carry a suspended load. An alarm unit for generating an alarm by light or sound based on a signal output by the control unit is provided in the main body or the operation device.

When the inching operation is continued for a long time,
Since a large current frequently flows through the motor, the temperature of the motor increases. The control means detects the temperature of the motor by means of the temperature detection means, and when the temperature approaches within a certain value from the upper limit of the allowable temperature of the motor 1, the warning means issues an alarm for warning of overheating. If the user recognizes the alarm and takes measures such as refraining from inching operation, the motor temperature further rises to reach the upper limit temperature, the temperature protector is activated and the motor is stopped, and the user is notified without notice. Work is not interrupted. When the motor temperature reaches the upper limit temperature, the control means cuts off the current to the motor, and until the motor temperature falls to a certain value.
The control unit stops the motor and does not accept the operation by the operation device. Therefore, even if the user ignores the alarm and continues the inching operation, the motor does not overheat.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electric hoist according to the present invention will be described below with reference to the drawings.

FIG. 1 is an external view of one embodiment of an electric hoist according to the present invention. The motor 1 is a rotating machine that generates a rotating force for lifting and lowering, and the rotating force is transmitted to the reduction mechanism 5. The control device 2 reads a signal from the operating device 8 and generates driving power for the motor 1 and the brake mechanism 4 based on the signal. The temperature sensor 40 is attached to the housing of the motor 1 and outputs the temperature of the motor 1 as an electric signal. The brake mechanism 4 mechanically stops the rotation of the speed reduction mechanism 5 under the control of the power supply by the control device 2, and is released only when the power is supplied, and is stopped when the power is not supplied.

Specifically, for example, the brake mechanism is a combination of a coil and a spring. When no power is supplied, the rotating portion is pressed by the force of the spring. I do. Therefore, if the energization control is performed in common with the motor 1, the motor 1 is released and stopped in synchronization with the rotation and stop of the motor 1.

The speed reduction mechanism 5 is a mechanism such as a gear for reducing the number of revolutions of the motor 1 and increasing the torque. This performs the hoisting and lowering of the chain 15. Actuator code 6 is
The controller 8 supports the operation device 8 and transmits a signal from the operation device 8 to the control device 2. The power cord 7 is an electric wire for supplying electric power to the electric hoist. The operating device 8 is used by a user to perform a lifting operation and a lowering operation, and the operation is performed by pressing down an operation button 9.

The operation button 9 is composed of both an up button 9a and a down button 9b. The control device 2 performs the operation of hoisting or lowering only while the operation button is being depressed, and is depressed. If there is no such operation, the operation is stopped.
The upper suspender 13 is a hook for suspending the entire electric hoist from a ceiling, a beam, or the like.

The lower suspender 14 is a hook that is attached to the end of the chain 15 and applies a suspended load. Chain 15
Is a metal chain or the like that is wound up or down by the rotation of the speed reduction mechanism 5. The chain storage box 16 is designed so that the end opposite to the suspended load of the chain 15 does not hang down during winding.
This is a box for storing the chain 15. The warning means 17 is a display means or a sounding means for expressing the upper limit of hoisting, the lower limit of lowering, overload, etc., and is arranged at the lower part of the electric hoist main body. In this example, the indicator lights 17a, 17b, 17c, 17
d and a buzzer 17e.

The upper part of FIG. 2A is a specific example of the alarm means 17. This is the upper limit indicator 17a, lower limit indicator 17
b, overheating warning lamp 17c, overheating indicator lamp 17d, and buzzer 1
7e.

The lower part of FIG. 2B shows an example of the type of alarm and the expression by each alarm means 17. When the upper limit is reached during winding, the upper limit indicator lamp 17a is turned on. Buzzer at the same time
17e sounds for 0.3 seconds. Even if the user presses the raising button 9a in this state, no power is supplied to rotate the motor 1 in the winding direction, and no further winding operation is performed. When the user presses the lowering button 9b to start the lowering operation, the upper limit indicator lamp 17a turns off. Similarly, when the lower limit is reached during the lowering, the lower limit indicator lamp 17b is turned on and the buzzer 17e sounds at the same time for 0.3 seconds.

In this state, no further lowering operation is performed. When the winding operation is started, the upper limit indicator light 17a
Turns off. If an overload exceeding the rated load is detected during hoisting, both the upper limit indicator lamp 17a and the lower limit indicator lamp 17b are turned on, and the buzzer 17e sounds for one second. In this state, no further winding operation is performed. When the lowering operation is started, both indicator lights are turned off.

When the temperature of the motor 1 reaches a constant temperature # 2 slightly lower than the upper limit # 1 of the permissible range (eg, 20 ° C.), the overheat notice lamp 17c is turned on and the buzzer 17e sounds three times in small increments. At this point, energization of the motor 1 is not stopped.

The lighting of the overheating warning lamp 17c is continued except when the temperature of the motor 1 is equal to or higher than $ 2 and the overheating indicating lamp 17d described below is lit. When the temperature of the motor 1 reaches the upper limit # 1 of the allowable range, the overheat indicator lamp 17d is turned on, and the buzzer 17e sounds five times in small increments.

In the lighting, when the temperature of the motor 1 is Θ1>Θ3>
The process is continued until the temperature drops to the constant temperature # 3 of # 2. During this time, the operation by the operation buttons 9a and 9b is not accepted. The method of detecting the upper limit, the lower limit, the overload and the motor temperature, and the operation of the control device 2 at the time of detection will be described later.

FIG. 3 is a block diagram showing the configuration of the electric hoist of FIG.

Hereinafter, the configuration of the control device 2 will be described. The control unit 20 is a circuit that reads a signal from the operation device 8 and the like according to a program recorded in advance therein and outputs a control signal for controlling the motor 1 and the like, and is a commercially available one-chip microcomputer or the like. It incorporates an A / D (analog-digital) converter 24.

The switch element 21 is a set of elements that conducts and cuts off current according to a control signal from the control unit 20. The control unit 20 controls the power supply to the motor 1 and the brake mechanism 4 by the switch element 21. Current detector 2
Reference numeral 2 denotes a current transformer that generates a low-voltage signal according to the current of the motor 1, such as a current transformer. The signal is transmitted to the control unit 2
It is read into an A / D (analog-digital) converter 24 within 0.

The anti-phase detection circuit 25 detects an erroneous connection of the power supply terminal and outputs a signal indicating the presence or absence of the erroneous connection. Control unit 2
0 reads the signal, and in the case of an incorrect connection of the power supply terminal, stops the power supply to the motor 1 to prevent the motor 1 from rotating in the reverse direction. Further, the control unit 20 outputs a signal for generating an alarm from the alarm unit 17.

The amplifier 26 amplifies the signal to a power sufficient to turn on the indicator lamp 17a and the like and to sound the buzzer 17e. The temperature sensor 40 is attached to the housing of the motor 1 and is a temperature-sensitive element such as a thermistor whose electric property such as resistance changes depending on the temperature. The interface circuit 41 outputs an electric signal corresponding to the electric property of the temperature sensor 40. Then, the electric signal is read into the A / D converter 24.

The limit switch 10 includes a switch having a structure that is opened when the chain 15 reaches the upper limit of hoisting and a switch that is opened when the chain 15 reaches the lower limit of lowering. In the case of the upper limit, the circuit for rotating the motor 1 in the hoisting direction is shut off, and in the case of the lower limit, the circuit for rotating the motor 1 in the hoisting direction is shut off. Information on the opening and closing of the limit switch 10 is read into the control unit 20.

FIG. 4 shows the motor 1 at the start of winding.
FIG. The current of the motor 1 is maximum at the moment of starting, decreases with an increase in the number of revolutions of the motor 1, and becomes a steady current that hardly fluctuates from one second to several seconds after starting. The steady current has a value corresponding to the load of the suspended load.

FIG. 5 shows an example of the relationship between the load at the time of hoisting and the steady current. Steady-state current increases with load. Therefore, an overload exceeding the rated load can be detected from the steady current. That is, in FIG. 5, the steady current corresponding to the rated load is set as the current threshold, and if the steady current exceeds the threshold, the overload is set. However, as shown in FIG. 4, a current larger than the threshold value flows immediately after the start of the motor 1, so that detection of overload due to the motor current is started after a lapse of a fixed time of about 2 seconds after the start of winding.

Hereinafter, the basic operation of the control unit 20 will be described with reference to the flowchart of FIG.

The control unit 20 waits for pressing of the up button 9a or the down button 9b. If the raising button 9a is pressed (s-1), and if the upper limit of the winding has not been reached (s-2), the controller 20 outputs a control signal to the switch element 21 and the motor 1 A current rotating in the direction is supplied. At the same time, the brake mechanism 4 is also energized and the brake is released (s-3).

The control unit 20 monitors the current of the motor 1, and if the current exceeds a certain threshold value, determines that an overload has occurred. However, since a large current flows immediately after the start of the motor 1, the current is not monitored for a certain time immediately after the start (s-4).
If the steady-state current of the motor 1 exceeds the threshold, (s−
5), the control unit 20 determines that an overload has occurred, and cuts off the power supply to the motor 1. As a result, the power supply to the brake mechanism 4 is also cut off, the brake is operated, and the motor 1 stops (s-
8).

Then, the control unit 20 generates an overload warning shown in FIG. 6 (s-9). In this case, if the user releases the up button 9a (s-18), the operation unit 20 returns to the standby state for pressing down the operation button 9 (s-1). When the upper limit is reached during winding and the limit switch 10 is opened (s-
6) As a result, the power supply to the motor 1 is cut off, the brake mechanism 4 is operated, and the motor 1 is stopped (s-1).
0).

The control unit 20 generates an upper limit alarm shown in FIG. 6 (s-11). If the user releases the up button 9a (s-18), the operation unit 20 returns to waiting for the depression of the operation button 9 (s-1). If the upper limit has already been reached when the up button is pressed (s-2), the control unit 2 does not rotate the motor 1 (s-10) and issues an upper limit alarm (s-1).
1) If the up button 9a is released (s-18), the process returns to the standby state for pressing down the operation button 9 (s-1).

When the down button 9b is pressed (s-
1) If the lower limit of the lowering has not been reached (s-12),
The motor 1 is rotated in the lowering direction (s-13). When the lower limit is reached during lowering and the limit switch 10 is opened (s-14), the motor 1 stops (s-16).

The control unit 20 generates a lower limit alarm shown in FIG. 6 (s-17). If the user releases the down button 9b (s-18), the operation unit 20 returns to the standby state for pressing down the operation button 9 (s-1). If the lower limit has already been reached when the lower button 9b is pressed (s-12), the control unit 2 does not rotate the motor 1 (s-16) and issues a lower limit alarm (s-17). When the down button 9b is released (s-1)
8), the process returns to waiting for the depression of the operation button 9 (s-1).

Hereinafter, a method for detecting the temperature of the motor 1 and generating an overheating alarm will be described.

FIG. 7 shows an example of the motor current when the rated load is hoisted by the inching operation. The inching operation is a process in which the user repeatedly presses and releases the hoist button 9a or the hoist button 9b in a short cycle of about 0.2 to 0.3 seconds, thereby energizing the motor 1 intermittently and gradually. This is the operation of winding up or down.

The point when the winding button 9a is pressed is the moment when the motor 1 starts rotating, and a large current flows. The current of the motor 1 decreases with an increase in the number of revolutions, but before the speed decreases, the hoist button 9a is released and the current is cut off. The interruption of the current activates the brake mechanism 4 and stops the motor 1. When the winding button 9a is pressed again, a large current at the start of rotation flows through the motor 1. As a result, a large current at the start of rotation of the motor 1 flows intermittently during the inching operation, and the average current I1 during this period has a large value.

The current when the winding button 9a is kept pressed is shown in the right part of the figure. The current of the motor 1 decreases as the number of rotations increases, and settles to the steady current I0. The average current I1 during the inching operation is larger than the steady current I0 when the rated load is wound. Therefore, if the inching operation is continuously performed for a long time, the average current exceeding the steady current I0 is continuously generated for a long time, so that the temperature of the motor 1 increases,
There is a risk of overheating.

FIG. 8 is a diagram showing an example of a change in the temperature of the motor 1 during the hoisting operation, and an operation performed by the controller 20 by detecting the temperature of the motor 1, such as an alarm generation and a stop of the motor 1. .

Before the start of operation, the temperature of the motor 1 is equal to the air temperature
Is the same as When a user starts operation and a current flows through the motor 1, the temperature of the motor 1 gradually increases. When the user continues the inching operation for a long time, the motor 1
Is less than or equal to the upper limit of a safety allowable range (hereinafter, this may be referred to as an allowable upper limit temperature) Θ1 and reaches a constant temperature こ れ 2 close thereto (hereinafter, this may be referred to as a notice temperature). Then, the control unit 20 generates an overheat notice alarm shown in FIG.

For example, if Θ1 = 180 ° C., Θ2 = 1
60 ° C. When the temperature of the motor 1 further rises and reaches the temperature # 1, the control unit 20 stops the motor 1 and stops accepting the operation by the operation button 9. Then, the overheating warning is canceled and the mode is switched to the overheating warning shown in FIG. When the power supply to the motor 1 is stopped, the temperature of the motor 1 gradually decreases. When the temperature of the motor 1 decreases to a constant temperature # 3 (hereinafter, sometimes referred to as a release temperature) of Θ1>Θ3> Θ2, the control unit 20 restarts accepting the operation, cancels the overheat alarm, and gives an overheat notice. Switch to alarm. Θ
3 is, for example, 170 ° C.

If the overheat alarm is released when the temperature of the motor 1 falls slightly below # 1, there is a risk that the overheat alarm will be generated for a short time and will not be recognized by the user. Also, if the user resumes operation immediately after the overheat alarm is canceled, the temperature of the motor 1 immediately reaches # 1, the motor 1 stops again, and an overheat alarm is generated. There is a risk of confusion.

Therefore, the generation of the overheat alarm is continued until the temperature of the motor 1 falls from # 1 to # 3, which has some margin. When the temperature of the motor 1 decreases to the notice temperature # 2 due to the user stopping the operation or the like, the control unit 20 cancels the overheat notice alarm.

FIG. 9 is a flow chart showing the operation of the control section 20 when the temperature of the motor 1 is detected and an alarm is issued.

When the power of the electric hoist is turned on, the control unit 20 resets an overheat flag indicating that an overheat alarm is being generated and an overheat flag indicating that an overheat alarm is being generated (t).
-1). Then, the temperature の of the motor 1 is read at a constant cycle of, for example, about 10 seconds (t-2).

While performing the basic operation shown in FIG. 6, the control unit 20 performs the following operation (t-2) as an interrupt process at the constant period. If the temperature 未 満 is less than the notice temperature Θ2 (t
-3), the control unit 20 cancels the overheating warning and resets the warning flag. To release the alarm, specifically, the overheating warning lamp 17c is turned off. Even if the cancellation operation is performed in a state where the overheating warning has not been generated, only the state where the warning has not been generated continues (t-4). And the control unit 20
Ends the interrupt processing.

If the temperature の of the motor 1 is equal to or higher than the allowable upper limit temperature Θ1 (t-3), the controller 20 cuts off the power supply to the motor 1 to stop it, and stops accepting the operation by the operation button 9. (T-5). Then, the overheating warning is canceled and the overheating warning flag is reset (t-6), and an overheating warning is generated by the overheating indicator 17d (t-7). If an overheat alarm has already been generated and the overheat flag has been set (t-8), the control unit 20 ends the interrupt processing. Immediately after Θ rises and reaches Θ1, and if the overheat flag is not set (t-8), the control unit 20 sets the overheat flag (t-9) and issues an overheat alarm by the buzzer 17e. To terminate the interrupt processing (t-10).

This is because if an overheat alarm has already been generated,
The lighting of the overheat indicator lamp 17d is continued, and when the temperature reaches the new temperature # 1, the indicator lamp is turned on and the buzzer 17e is turned on.
Is called to call the user's attention.

If the temperature モ ー タ of the motor 1 is less than the allowable upper limit temperature か つ 1 and the notice temperature Θ2 (t-3), if the overheat flag is not set (t-11), the control unit 20 operates the overheat notice lamp 17c. Generate an overheat warning (t-1)
2). If an overheating warning has already been generated and the overheating warning flag has been set (t-13), the control unit 20 ends the interrupt processing. Immediately after Θ rises and reaches Θ2, and the overheat notice flag is not set (t−
13), the control unit 20 sets an overheat notice flag (t-
14), an overheating warning is generated by the buzzer 17e, and the interruption process is terminated (t-15).

If Θ once falls to Θ1 and then descends, an overheat alarm is being generated and the overheat flag is set (t-11), if Θ is equal to or greater than the release temperature Θ3 (t
-16), the control unit 20 generates an overheat alarm by the overheat indicator lamp 17d, and ends the interrupt processing (t-17).

When Θ falls below the cancellation temperature Θ3 (t-16), the control unit 20 cancels the overheat alarm, resets the overheat flag (t-18), and gives an overheat notice lamp 17c.
Then, an overheating warning is generated by the buzzer 17e and the overheating warning flag is set (t-19). And operation button 9
Is resumed, and the interrupt processing ends.

Hereinafter, an example in which the alarm means 17 is provided in the operation device 8 will be described. FIG. 10 shows that the alarm means 17
It is an external view of the electric hoist provided in. The same components as those in FIG. 1 are denoted by the same reference numerals. The indicator lamps 17a to 17d and the buzzer 17e are provided on the surface of the operation device 8. A signal for turning on each indicator lamp or sounding the buzzer 17e is transmitted by the operating device code 6.

FIG. 11 is a block diagram showing the configuration of the electric hoist of FIG. The same components as those in FIG. 3 are denoted by the same reference numerals. When the control unit 20 generates an alarm, the signal output by the control unit 20 is amplified by the amplifier 26, reaches the operation device 8 through the operation device code 6, turns on each indicator lamp, and sounds the buzzer 17e. .

Hereinafter, an example in which an alarm means is provided in a two-way wireless operation device will be described. It transmits and receives bidirectional wireless signals between the wireless remote controller and the hoist body.
In this example, the operation information is transmitted from the wireless remote controller to the main unit of the hoist using infrared rays, and information relating to the generation of an alarm is transmitted from the main unit of the hoist to the remote controller using infrared rays.

FIG. 12 is an external view of the electric hoist of this embodiment. The same components as those in FIG. 1 are denoted by the same reference numerals. The first light receiver 3 is provided at a lower portion of the main body of the hoist, and receives infrared light in a specific wavelength range and converts the infrared light into an electric signal. In order to prevent the infrared rays from being blocked by the chain storage box 16 and the like, a plurality of infrared rays are provided separately from each other. The wireless remote controller 30 is for the user to operate the electric hoist by pressing down a button, and to transmit information of the operation to the main body of the hoist by infrared rays, and has an operation button 31. These consist of an up button 31a and a down button 31b.

The first light emitting device 32 and the second light emitting device 18 generate infrared rays of a specific wavelength, such as infrared light emitting diodes. The first light emitter 32 is provided in the wireless remote controller 30, and the second light emitter 18 is provided in a lower part of the hoist main body. First light receiver 3 and second light receiver 3
Numeral 3 is for receiving the infrared rays and generating an electric signal. The first optical receiver 3 is provided at a lower portion of the electric hoist main body, and the second optical receiver 33 is a wireless remote controller 30. Is provided in the vicinity of the light emitter 32.

The alarm means 34 is provided on the surface of the wireless remote controller 30 and, like the alarm means 17, comprises an upper limit indicator light 34a, a lower limit indicator light 34b, and a buzzer 34c.
No alarm means 17 is provided in the main body of the hoisting machine.

FIGS. 13A and 13B are block diagrams showing the configuration of the electric hoist of FIG. The same components as those in FIG. 3 are denoted by the same reference numerals. The first demodulator 11 is provided in the main unit of the hoist and converts an electric signal generated when the first light receiver 3 receives infrared rays into a digital signal. Is read in. The first modulator 35 is provided in the wireless remote controller 30, detects a pressed state of the operation button 31, generates an electric signal representing the pressed state, and uses the electric signal to generate a first light emitter 32. Is to emit light.

The second modulator 19 is provided in the main unit of the hoist and converts a digital signal output from the control unit 20 into an electric signal for causing the second light emitter 18 to emit light.
The second demodulator 36 is provided in the wireless remote controller 30 and converts an electric signal generated when the second light receiver 33 receives infrared rays into a digital signal. The signal is amplified by the amplifier 37, the indicator lights 34a and 34b are turned on, and the buzzer 34c sounds.

The digital signal output when the control section 20 performs the operation for generating each of the above-mentioned alarms is transmitted to the second modulator 1
The second light emitter 18 generates an infrared ray according to the electric signal. In the wireless remote controller 30, when the second light receiver 33 receives the infrared ray, an electric signal is generated by the second light receiver 33, and the electric signal is demodulated to a digital signal by the second demodulator 36, and the electric signal is amplified by the amplifier 37. After being amplified, each indicator light 34a,
The buzzer 34c is turned on or the buzzer 34c sounds.
As described above, the user can recognize the generated alarm on the wireless remote controller 30 at hand.

[0063]

As described above, according to the present invention, the temperature of the motor of the electric hoist is detected, and when the temperature approaches within a certain range from the upper limit of the allowable range, an alarm by display or sound is issued. Since a warning of an overheating warning is generated by the means, the user is notified in advance of the possibility of overheating of the motor and can take measures such as refraining from driving that causes heat generation of the motor such as inching operation, etc. During the operation, the temperature protector is suddenly operated without notice, the motor is stopped, and the operation is not interrupted until the temperature protector returns.
When the temperature of the motor reaches the upper limit of the allowable range, the motor is automatically stopped, and the operation of the user is not accepted until the temperature drops to a certain value. Even when the operation is continued ignoring the warning of the overheating notice, the temperature does not exceed the upper limit and does not lead to overheating.

Further, if the alarm means is provided in the operating device on which the user operates the buttons, the alarm can be more reliably recognized at hand without the user paying attention to the main body of the hoist.

[Brief description of the drawings]

FIG. 1 is an external view of one embodiment of an electric hoist according to the present invention.

FIGS. 2A and 2B are a configuration diagram showing an example of an alarm unit and an alarm to be generated, and a diagram showing types of alarms.

FIG. 3 is a block diagram of one embodiment of an electric hoist according to the present invention.

FIG. 4 is a characteristic diagram illustrating an example of a motor current during winding.

FIG. 5 is a characteristic diagram showing an example of a relationship between a hoisting load and a steady current of a motor.

FIG. 6 is a flowchart showing the operation of the control unit 20 at the time of hoisting and lowering.

FIG. 7 is a characteristic diagram illustrating an example of a motor current during inching.

FIG. 8 is a characteristic diagram illustrating an example of a change in motor temperature.

FIG. 9 is a flowchart illustrating an operation of the control unit 20 when an alarm is generated.

FIG. 10 is an external view of an embodiment in which an alarm device is provided in an operation device.

FIG. 11 is a block diagram of an embodiment in which an alarm device is provided in an operation device.

FIG. 12 is an external view of an embodiment in which an alarm unit is provided in a two-way wireless operation device.

FIG. 13 is a block diagram of an embodiment in which an alarm unit is provided in a bidirectional wireless operation device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Motor, 2 ... Control device, 3, 33 ... Light receiver, 4 ... Brake mechanism, 5 ... Deceleration mechanism, 6 ... Actuator code, 7 ... Power cord, 8 ... Actuator, 9, 31 ... Operation button, 10 …
Limit switches, 11, 36 demodulator, 13 upper hanging tool, 14 lower hanging tool, 15 chain, 16 chain storage box, 17, 34 alarm means, 18, 32 light emitter,
19, 35 modulator, 20 control unit, 21 switch element, 22 current detector, 24 A / D converter, 25 antiphase detection circuit, 26, 37 amplifier, 30 wireless remote control Device, 40: temperature sensor, 41: interface circuit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaaki Sato 1-1-1, Higashitagacho, Hitachi City, Ibaraki Prefecture Inside the Taga Headquarters, Hitachi, Ltd.Electrical Equipment Division (72) Inventor Takahisa Mukata Higashitaga, Hitachi City, Ibaraki Prefecture 1-1-1, Machi, Hitachi, Ltd.Electrical Equipment Division, Taga Headquarters

Claims (4)

[Claims] 1. A motor, a speed reduction mechanism for reducing the rotation of the motor, a brake mechanism for stopping the rotation of the speed reduction mechanism, a control means for controlling the motor and the brake mechanism, and controlling a temperature of the motor. A temperature detecting means for detecting and transmitting the light to the control unit, and an output signal from the control means,
An electric hoist main body including alarm means for generating an alarm by a sound or the like, a cable wound up and down by the speed reduction mechanism,
A lower hanging device attached to the lower end of the cable and for hanging a load, an upper hanging device attached to the upper portion of the electric hoist main body and suspending the main body, and a user hoisting and winding by pressing a button or the like. In an electric hoist comprising an operating device for performing an operation such as lowering, and transmission means for transmitting operation information from the operating device to the control device, the control device includes: When the temperature is equal to or higher than the predetermined temperature, an alarm indicating overheating is generated by the alarm means and the motor is stopped, and the temperature of the motor is lower than the first predetermined temperature and lower than the first predetermined temperature. An electric hoist, wherein when the temperature is equal to or higher than a predetermined temperature, an alarm for giving notice of overheating is generated by the alarm means. 2. The alarm device according to claim 1, wherein
An electric hoist provided in the operation device. 3. The control device according to claim 1, wherein
After the temperature of the motor reaches the first constant temperature,
Until the temperature falls below the first constant temperature and lower than a third constant temperature that is higher than the second constant temperature, an alarm indicating the overheating is generated and the motor is stopped. An electric hoist. 4. The operation device according to claim 2, wherein the operation device is a wireless operation device that wirelessly transmits operation information.
A first transmission unit for transmitting the operation information by a wireless signal,
The electric hoist main body includes first receiving means for receiving the radio signal and transmitting the radio signal to the control means, and the electric hoist main body converts a signal output by the control means into a radio signal. The operating device comprises: a second receiving means for receiving the radio signal and outputting a signal; and an alarming means for generating an alarm based on the signal, and the control means. Is an electric hoist, wherein a radio signal is transmitted from the second transmission means, and the second reception means receives the radio signal and generates an alarm by the alarm means.