JPH079899Y2 - Electric hoist - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an electric hoist used for lifting medium / lightweight objects in a narrow space in a plant.

[Conventional technology]

Relatively light temporary lifting work in narrow spaces (for example, inspection and repair work of valves in plants) and work that requires delicate control are often performed manually with chain blocks, and are manually performed. Was needed. Winding using a chain block has to be carried out in close contact with pollutants, which is a factor of increased exposure at nuclear power plants.

[Problems to be solved by the device]

In power plants, chemical plants, etc., lifting of heavy objects often occurs in a narrow place without a crane. For example, there are periodic inspections and repairs of various valves used in many plants. In such a case, conventionally, as shown in FIG. 3, a chain block 32 is set up on site and the chain block 31 is used to lift the valve cover 36 of the valve 35 being disassembled. The chain block has the advantage that it can be finely adjusted in speed, but it requires manual work by a person, long-time work does not cause fatigue, and it is necessary to perform position adjustment in addition to the worker 33 who performs manual work. In some cases, a work assistant 34 is required, which is inefficient.

Further, the conventional ON / OFF switch or several-stage speed switching switch type hoist has a difficult delicate operation, and is not suitable for positioning such as valve assembly or work that is averse to shock.

Furthermore, in the electric hoist of the control system that does not apply feedback only by performing voltage control and inverter control,
The speed is not constant due to the weight of the suspended load, and it is difficult to work at low speeds that require delicate control. In particular, it is not possible to perform the most required fine speed control of heavy objects.

When using a normal electric hoist, two stages of ON and OFF,
Even if there are several steps, hoist operation by speed control only requires visual position detection and real-time feedback to the operation amount (moving while looking, decelerating just before hitting) is not suitable for automation. is there.

[Means for Solving the Problems]

Speed servo, position servo, servo driver that can select speed control and position control by feeding back sensor signals of each servo, brake driver that opens by energization, and each driver is operated by speed command and position command It is characterized in that it is provided with a control device for controlling.

[Action]

(1) Speed control The hoist body includes a servo motor and a speed detector, and the servo motor is controlled by a driver having a speed servo function using a speed signal measured by the speed detector.

(2) Position control The position of the hook can be controlled by comparing the position of the hook with the position command value and the position obtained from the position detector to control the position of the hook.

(3) Stop by force detection The force detector detects the weight of the suspended load and its change, compares the detected force with a preset value, and the result can be used to stop during operation by speed control.

(4) Switching of control method A stop switching command by speed control, position control and force detection and those speed, position and force commands are given by an operator remotely or externally by a computer or the like and operated.

(5) Brake The drum can be locked at any position while suspending a suspended load by an electric brake or a self-locking mechanism.

(6) Function as an electric hoist (b) By using a speed servo, it is possible to control from a very low speed to a high speed according to the operator's or computer's command regardless of the weight of the suspended load.

(B) By using the position servo, the suspended load can be moved accurately and promptly without visually confirming the desired position.

(C) By using a force sensor, it is possible to stop automatically when the load is grounded when unloading the load by speed control.

(D) The above methods (a), (b) and (c) can be selected and used according to need.

〔Example〕

In FIGS. 1 and 2, 1 is a chain, 2 is a chain sprocket wheel, 3 is a speed reducer, 4 is a wire rope drum, 5 is a limit switch, 6 is a wire rope, and 7 is a wire rope drum.
Is an electric release brake, 8 is a servomotor, 9 is a tachogenerator, 10 is a moving pulley, 11 is a hook, 12 is a control box, 13 is an external input / output connector, 14 is a hoist frame,
Reference numeral 15 is a cable, 16 is a position detection encoder, 17 is a force (tension) sensor, 201 is a hoist body, 202 is a servo driver capable of selecting speed control and position control, 203 is a brake driver, and 204 is a force comparison device. 205 is a control device that locks the brake and stops the servo motor when the hoist is stopped by a speed command or a position command or when a stop command by force detection is received. 206 is a manual operation (external operation switching switch), 207 is a force command setter, 208 is a control method selector, and 209 is a speed / position command setter.

The hoist frame 14 has motor units 7, 8, 9, 16 and wire rope drum units 3, 4. The servo motor 8 is combined with a speed servo tachogenerator 9 that coaxially detects the speed, a brake 7 that is released by energization, and a position servo encoder 16 that detects the position.
Motor torque is chain 1 and chain sprockets 2
Is transmitted to the speed reducer 3. One end of the speed reducer 3 is fixed to the hoist frame 14, the output shaft is connected to the drum 4, and the drum 4 is rotated by the output. The wire rope 6 is wound up by the rotation of the drum 4, and the hook 11 attached to the moving pulley 10 is moved up and down to lift and lower the suspended load. A limit switch 5 is attached to the upper part so as not to wind the hook too much. Control the cable 15
Via a control box 12 placed at the operator's hand either manually or externally (for example, a computer or the like) through an external input connector 13. The power supply is, for example, AC100V.

FIG. 2 shows an example of a hoist control device according to the present invention. The hoist body 201 includes a servo motor 8, an energization release type brake 7, an encoder 16, a tachogenerator 9, and a force sensor 7. A cable 15 is connected to the control box 12.

The control is switched by the switching switch 206 between external input / output and remote manual operation from the operation panel. Here, a manual operation will be described, but in the case of external input / output, the following signals are input / output externally.

First, the control method selector 208 controls speed, position,
Select whether to stop by force detection. These commands are sent to the servo driver 202 and the force comparison device 204. Next, a speed command or a position command is set by the speed / position command setting device according to each control method. This signal is sent to the servo driver for servo control. Also,
When the speed and position become equal to the command value, the motor stops, but at that time, the control device 205 commands the brake driver 203 to perform a brake lock. When stopping by force detection, the force is set by the force command setter, and if it is equal to the detected value of the force sensor or if it is within the allowable range, a stop command is given to the control device 205.

In this figure, the limit switch, the emergency stop switch, and the power supply device are omitted.

[Effect of device]

The electric hoist of the present invention includes a speed servo and a position servo,
A servo driver that can select between speed control and position control by feeding back sensor signals of these servos, a brake driver that is opened by energization, and a control device that operates and controls each driver according to a speed command and a position command. Since the speed control is provided with a predetermined speed, a required speed can be obtained, and the position control can be given a predetermined position and stopped at a required position regardless of the suspension load amount. , And has an effect of enabling accurate positioning by controlling continuously from fine speed to high speed in a well-balanced manner.

[Brief description of drawings]

1 (a) and 1 (b) are a front view and a side view showing the configuration of a servo-controlled electric hoist as an embodiment of the present invention, and FIG. 2 is an example of the configuration of an electric equipment / control system of the hoist according to the present invention,
FIG. 3 shows an example of valve disassembly work in a conventional power generation or chemical plant by a chain block. 3 ... reducer, 4 ... wire rope drum 6 ... wire rope, 7 ... energization release brake 8 ... servo motor, 9 ... tacho generator 13 ... external input / output connector 16 ... encoder, 17 ... force (Tension) sensor 202 …… Servo driver 203 …… Brake driver 204 …… Force comparison device, 205 …… Control device

Continuation of the front page (56) References JP-A-53-142750 (JP, A) JP-A-52-41342 (JP, A) Japanese Patent Application No. 52-115802 (No. A microfilm (JP, U) of the attached specification and drawings

Claims (1)

[Scope of utility model registration request] 1. A speed servo, a position servo, a servo driver capable of selecting a speed control and a position control by feeding back sensor signals of these servos, a brake driver which is opened by energization, and each of the drivers as a speed command. An electric hoist comprising: a control device that operates and controls according to a position command.