JP5809788B2 - Electric hoist with earthing stop mechanism - Google Patents

Description

  The present invention relates to an electric hoist that lifts a heavy object, and more particularly, to an electric hoist equipped with a mechanism that discriminates and immediately stops a ground cutting of an electric hoist.

When a hoisting command is issued at the time of hoisting by an electric hoist, the load meter detects the presence or absence of a load, and measures the time or distance from when the load is detected until the hoisting command stops within the sequencer. Then, this measured value is compared with a preset value, and when the measured value is large, it is determined that the stoppage is defaulted when the ground is cut (see Patent Document 1). The ground cutting means a state in which the load is separated from the ground by hoisting.

JP-A-5-97387

  When lifting a load using an electric hoist, it is necessary to stop and immediately check the sling, such as whether the sling wire tension is stable or the load is stable, just before the ground is cut. This is because when the hoisting is performed without stopping at the time of ground cutting, an excessive load is applied to the slinging wire, and there is a risk of cutting or the like.

  There is a method using the input current as a method for obtaining the load information. However, since variations occur depending on the power supply voltage, accurate load information cannot be obtained and the ground cutting judgment is not stable. Moreover, when obtaining load information with the load meter described in Patent Document 1, it is necessary to use a special device, and there is a problem that costs increase. Furthermore, the operation is only monitored, and the hoisting continues without confirming safety, and a dangerous state such as cutting of the sling wire may occur. For this reason, when lifting a load, it is necessary to reliably determine immediately before the earth is cut and temporarily stop it, resulting in a decrease in work efficiency.

To solve the above problems, for example, an electric motor, hoisting the wire rope by driving the electric motor, or the electric hoist to perform unwinding operation, the winding operation detecting means for detecting a winding operation, motor A rotational speed detecting means for detecting the rotational speed of the motor, a rotational speed comparing means for comparing the previously detected motor rotational speed with the newly detected motor rotational speed, a current value detecting means for detecting a current value, and the current Out of the current values detected by the detection means, current value comparison means for comparing a current value already detected with a current value detected after the already detected current value, and the rotation speed detection means The number of rotations of the motor is detected, and the number of rotations of the motor detected by the rotation detection unit by the rotation number comparison unit and the previous rotation of the motor detected by the rotation detection unit When the rotation speed is determined to be the same value, the current detection unit detects a current value, and among the current values detected by the current value detection unit, the current value already detected determined to be ground cutting when more is larger the current value has already been detected after the detected current value, a configuration called.

  According to the present invention, since the hoist detects immediately before the ground cut and automatically stops, confirmation can be urged before lifting the load, and safety such as inspection of sling can be improved.

  Further, according to the present invention, it is not necessary to use a device that is not originally required for an electric hoist, so that cost can be reduced.

  Hereinafter, embodiments will be described with reference to the drawings. The present invention is not limited to the illustrated example.

First, the overall configuration and operation of the inverter crane apparatus 1 will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, the inverter type crane apparatus 1 has a traverse girder 8 on which a hoisting device 5 having a hoisting induction motor 4 and a traversing device 7 having a traverse induction motor 6 are integrally mounted. ing. The hoisting and traverse inverter device 12 provided in the hoisting device 5 stores an inverter control unit 13, a hoisting inverter 15, and a traverse inverter 16. A wire rope 3 having a hook 2 as a moving pulley is wound around the drum inside the hoisting device 5, and the input device 14 is connected to the inverter control unit 13. The hoisting dielectric motor 4 and the traverse induction motor 6 are provided with an induction motor brake 17.

  The traverse girder 8 is fixed to a travel device 10 including a travel induction motor 9 and travels on the travel girder 11. A traveling inverter control unit 19 and a traveling inverter 20 are stored in the traveling inverter device 18. Further, the traveling induction motor 9 is provided with an induction motor brake 17.

  An operation command is issued from the input device 14 and the inverter control unit 13 takes in an operation instruction. In the case of a winding / lowering instruction, the winding rope 15 is controlled by controlling the winding inverter 15 and applying the necessary frequency and voltage from the winding inverter 15 to the winding induction motor 4 to release the induction motor brake 17. The hook 2 which suspended the load via 3 is moved in the Z and -Z directions without the suspended load falling. In the case of a traverse instruction, the traverse inverter 16 is controlled, and the hoisting device 5 is moved in the X and -X directions by adding the necessary frequency and voltage from the traverse inverter 16 to the traverse induction motor 6.

  Similarly, the traveling induction motor 9 attached to the traveling device 10 outputs an instruction signal from the input device 14 by the traveling inverter control unit 19 stored in the traveling inverter device 18, thereby outputting the traveling inverter 20. And by applying the necessary frequency and voltage from the traveling inverter 20 to the traveling induction motor 9 and controlling the release of the induction motor brake 17, the hoisting device 5 is moved along the traveling girder 11 to Y, − Move in the Y direction.

  Hereinafter, the present invention will be described with reference to FIGS. 1, 3, 4, and 5. FIG. 3 is a block diagram showing the hoisting control structure of the present invention. In this hoisting-up control configuration, a hoisting / row traverse inverter device 12 for performing various controls and a hoisting inverter 15 are stored. The input device 14 that sends an operation command to the hoisting / traverse inverter control unit 13, the hoisting induction motor 4 driven by the hoisting inverter 15, the induction motor brake 17 that holds the suspended load when stopped, and the hoisting induction motor 4 It comprises an encoder 21 that sends a pulse signal to the hoisting / traverse inverter control unit 13 in accordance with the rotation.

  The hoisting / traversing inverter control unit 13 repeatedly detects the motor rotation speed and the current value during the operation, compares them in time series, and makes a judgment of ground cutting by capturing the change. If the detected value meets the condition, it is determined that the ground is cut and the induction motor brake 17 stops the ground. The ground cutting judgment is performed with the frequency fixed at 6 Hz.

FIG. 4 is a flowchart showing the earth cutting stop control. The input device 14 determines the presence or absence of a hoisting command in the determination A. When receiving the hoisting command, the hoisting inverter 15 is controlled by the process A, the necessary frequency and voltage are applied to the hoisting induction motor 4, and the hoisting induction motor 4 starts the hoisting. If no winding command has been received, return to decision A.
When the winding is started, it is determined by judgment B whether 0.1 second has elapsed since the process A was performed. When 0.1 second has elapsed, it is determined by judgment C whether the hoisting command is continuously input. If 0.1 second has not elapsed, the process returns to decision A. When a winding command is received, a pulse signal generated in accordance with the motor rotational speed is received from the encoder 21 connected to the winding induction motor 4 by process C, and the rotational speed is controlled by the winding / traverse inverter control unit 13. To detect. If no winding command has been received, it is determined in process B that the winding is stopped.

The motor rotation speed detected in process C and the motor rotation speed detected previously are compared in judgment D, and if they are the same as d2 and d3 in FIG. 15, the current value is detected by the hoisting / traverse inverter control unit 13. If the detected motor rotation speed and the previously detected motor rotation speed are not the same as d1 and d2 in FIG. 5A, the process returns to decision C.
After detecting the current value in process D, it is determined in decision E whether 0.1 second has elapsed since process D was performed. When 0.1 second has elapsed, it is determined by judgment F whether the hoisting command is continuously input. If 0.1 second has not elapsed, the process returns to process D. When a winding command is received, a pulse signal from the encoder 21 is received by process F, and the motor rotation speed is detected by the winding / traverse inverter control unit 13. If no hoisting command has been received, hoisting is stopped in process E.

  The motor speed detected in process F is compared with the motor speed detected before by judgment G. If the detected value is smaller than the previously detected value as shown in d3 and d4 in FIG. 5-1, it is applied. It is determined that the engine speed has decreased, and the process proceeds to determination H. When the detected value is larger than the previously detected value as in d1 and d2 in FIG. 5-1, the load is increased during acceleration, and when the detected value is the same as the previously detected value as in d2 and d3. It is determined that the state is not applied, and the process returns to determination F.

  It is determined whether 0.1 second has elapsed since the determination G was made in the determination H. If 0.1 second has elapsed, the process moves to decision I. If 0.1 second has not elapsed, the process returns to decision H. Judgment I determines whether the input device 14 has received a hoisting command. When the hoisting command is continuously input, the hoisting / traverse inverter control unit 13 detects the motor rotation speed from the pulse signal input from the encoder 21 by the process H. When the hoisting command is not received, it is determined in process G that the hoisting is stopped.

The motor rotation speed detected in process H and the motor rotation speed detected previously are compared by judgment J. If the values are the same as d5 and d6 in FIG. 5-1, the stable state is judged and judgment K is judged. It is determined whether 0.3 seconds have elapsed since J was performed. If the values are different, such as d4 and d5 in FIG. 5-1, the process returns to decision I.
If 0.3 seconds have passed in judgment K, it is checked in judgment L whether a winding command is continuously input. If 0.3 seconds have not elapsed, the process returns to decision K. When the winding command is received in the determination L, the motor rotation speed is detected from the pulse signal input from the encoder 21 connected to the winding induction motor 4 by the process J. If the winding command has not been received, the winding is stopped in process I.
The motor rotational speed detected in process J is compared with the motor rotational speed detected previously in judgment M. If the values are the same as d6 and d7 in FIG. 5-1, current value is output from the winding inverter 15 by process K. Is detected by the hoisting / traverse inverter control unit 13. If the value is different, return to decision L.

  The current value detected in process K is compared with the current value detected previously in judgment N. If the detected value is larger than the previous detected value as shown in d3 and d7 in FIG. By controlling the induction motor brake 17 from the hoisting / traverse inverter control unit 13 by L, the operation of the hoisting induction motor 4 is stopped and stopped. If the detected value is smaller than or equal to the previous detected value, the process returns to process K.

After stopping the ground cutting by the process L, the hoisting / traverse inverter control unit 13 judges the presence / absence of a hoisting command from the input device 14 at decision O as shown in FIG. Based on the judgment P, the presence / absence of the winding command is confirmed again. If the command continues, stop.
This is the end of the judgment of ground cutting.

In the following, a procedure for landing a load at the lower end of the roll after the ground cutting and moving to the judgment of the ground cutting again will be shown.
In the judgment P, when there is a hoisting command, the ground cutting stop is canceled, the hoisting inverter 15 is controlled by the process M, the necessary frequency and voltage are added to the hoisting induction motor 4, and the hoisting induction motor 4 performs the hoisting operation. Start on.

  It is determined whether or not a lowering command has been received from the input device 14 in determination Q after the start of winding. When a roll-down command is received, it is determined whether 0.1 second has elapsed since the determination Q was made in the determination R. If no unwind command has been received, return to decision Q. When the determination R is 0.1 seconds, a pulse signal generated in accordance with the motor rotation is received from the encoder 21 connected to the hoisting induction motor 4 by processing N, and the rotation speed is set to the hoisting / traverse inverter control unit 13. Detect with. If 0.1 second has not elapsed, the process returns to decision R.

  The motor rotational speed detected in process N is compared with the motor rotational speed detected previously in judgment S. If the detected value is larger than the value detected previously, 0 after judgment S or judgment U is performed in judgment T Determine if 1 second has passed. If the detected value is the same or smaller than the previous detected value, the process returns to decision R. When it is determined that 0.1 second has passed in the determination T, a pulse signal generated in accordance with the motor rotation is received from the encoder 21 connected to the hoisting induction motor 4 by processing O, and the rotation speed is determined as the hoisting / traverse inverter. It is detected by the control unit 13. If 0.1 second has not elapsed, the process returns to decision T.

  The motor rotational speed detected in process O and the motor rotational speed detected previously are compared in decision U. If the detected value is the same as the previously detected value, the current value is wound from the winding inverter 15 by process P. Detected by the up / down inverter control unit 13. If the detected value is not the same as the previously detected value, the process returns to decision T.

  The value detected in the process P and the current value detected before are compared by the determination V. When the detection value is smaller than the previous detection value, it is determined as the landing in FIG. If the detected value is greater than or equal to the previous detected value, the process returns to process P.

  If it is determined that the landing has been made in the determination V, the determination returns to the determination of the ground cutting again.

  The detection waiting time shown in the description is not an absolute numerical value for carrying out the present invention, but is determined by processing response and detection timing.

It is a perspective view showing the whole structure of an inverter type crane apparatus. It is a block diagram showing an inverter crane control configuration. It is a block diagram showing winding-up control structure. It is a flowchart showing the earthing stop control concerning this invention. It is a time chart showing the electric current value and rotation speed concerning this invention.

DESCRIPTION OF SYMBOLS 1 ... Inverter type crane apparatus, 2 ... Hook, 3 ... Wire rope, 4 ... Hoisting induction motor, 5 ... Hoisting apparatus, 6 ... Traverse induction motor, 7 ... Traverse apparatus, 8 ... Traverse girder, 9 ... Traveling induction motor, 10 ... Traveling device, 11 ... Traveling girder, 12 ... Hoisting and traverse inverter device, 13 ... Hoisting / traverse inverter control unit, 14 ... Input device, 15 ... Inverting inverter, 16 ... Traverse For inverter, 17 for brake for induction motor, 18 for inverter device for traveling, 19 for traveling inverter control unit, 20 for inverter for traveling, 21 for encoder

Claims (2)

In the electric hoist that performs the winding operation or the lowering operation of the wire rope by driving the electric motor and the electric motor,
Hoisting motion detecting means for detecting hoisting motion;
A rotational speed detection means for detecting the rotational speed of the motor;
A rotational speed comparison means for comparing the previously detected motor rotational speed with the newly detected motor rotational speed;
Current value detecting means for detecting a current value;
Of the current values detected by the current detection means, current value comparison means for comparing a current value already detected with a current value detected after the current value already detected;
With
The number of revolutions of the electric motor is detected by the number of revolutions detecting means, the number of revolutions of the motor detected by the number of revolutions detecting means is detected by the number of revolutions comparing means, and the previous rotation of the motor detected by the rotation detecting means. When the number of rotations is compared and it is determined that the number of rotations is the same value, the current detection unit detects a current value, and among the current values detected by the current value detection unit, the current already detected Determining whether the current value detected after the already detected current value is greater than the value ,
The number of rotations of the electric motor detected by the rotation detection means and the number of rotations of the electric motor detected by the rotation detection means are determined to be the same value, and are already detected from the already detected current value. An electric hoist characterized by determining that the current is detected after the detected current value is greater than the current value .   2. The electric hoist according to claim 1, wherein the electric motor includes a brake, and when the electric hoist is determined to be ground cutting, the hoisting operation is stopped by the brake.

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