JPH0286598A - Crane combined lifting uniform speed controlling method - Google Patents

Abstract

PURPOSE:To maintain each hook level of two crabs in horizontality with yet more certainty by discriminating a difference in these hook levels from a speed difference between first hoisting drum revolution and second hoisting drum revolution of both these crabs, and controlling inverter controlling frequency. CONSTITUTION:Each signal of both first and second synchro transmitters 5, 6 installed in each turning shaft of respective hoisting drums 1, 2 is received by a differential receiver 7, finding a speed difference between both these hoisting drums 1, 2, and a difference in both first and second hook levels is measured. For example, when a hook level of a first crab is increased, command frequency to a first electric motor M1 is lowered, and lifting speed of a hook of the first crab is decelerated. In contrast with this, when the hook level of the first crab is decreased, the command frequency to the first motor M1 is raised up to some extent, and the lifting speed of the hook of the first crab is increased. Thus, the hook levels of both crabs are equalized, whereby a long material such as a vehicle or the like is maintained in horizontality and thus combined lifting crane operation is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION 0 Industrial Field of Application The present invention provides a method for raising and lowering a long object such as a vehicle while always maintaining the hook level of both clubs in a horizontal state when carrying out a work of suspending a long object such as a vehicle with two clubs. The present invention relates to a crane-suspended speed control method.

BACKGROUND ART As a method for controlling the same speed when hoisting both cranes, there is a known method in which the hook levels of both clubs are detected and the level of the hooks of the winding motors is controlled to be zero.

0 Problems with the prior art In the prior art described above, the speed fluctuations due to the unbalance of the hanging load are large, and the response time is long, resulting in a time delay in speed correction and insufficient synchronized operation of the hooks of both clubs. There was a problem.

0 Means for Solving the above-mentioned Problems The present invention compares the rotational difference of the respective hoisting drums of both clubs to determine the hook level of both clubs when the two clubs are hung together. Advancement of the hook level against the other.

The delay is detected and the frequency of the inverter control for the motor is increased or decreased to equalize the winding speed of both clubs.

O Example The following description will be made based on the embodiments shown in the drawings.

When hoisting a long object A such as a vehicle with two clubs, the first club hoisting drum 1 is connected to the first club hoisting drum 1 of the squirrel cage induction motor.
The second club hoisting drum 2 is driven by a second electric motor M2 which is also a squirrel cage induction motor, and the conductive motors Ml and M2 are controlled by a first inverter control device W13 and a second inverter control device RA4, respectively. By controlling the inverter and changing the command frequency for both inverter control devices @3.4, the hoisting speed of both clubs (the lifting speed of the hook) can be changed freely.

The present invention compares both hook levels and lowers the command frequency for the electric motor on the side where the hook level is advanced, or increases the command frequency when the hook level is behind, so that both hook levels are compared. to maintain the hook level horizontally.

That is, eight first synchronizers are installed on the rotating shafts of each hoisting drum 1 and 2.5. The difference in rotation of No. 18 of the second synchro transmitter 6 is detected by the differential receiver 7, and the difference in hook level is measured.

If the hook level of the first club is increasing, the command frequency f1 for the first electric motor M1 is lowered, and the lifting/lowering speed v1 of the hook of the first club is decelerated.

When the hook level of the first club is decreasing,
The command frequency @f2 for the electric motor M1 is increased, and the lifting/lowering speed v2 of the hook of the first club is increased.

In this way, when performing co-suspension crane work using both clubs, the hook levels of both clubs are made equal, and the long object A, such as a vehicle, is maintained horizontally.

Effects of the Invention The present invention, when co-hanging two clubs, determines the difference in the level of the hook based on the rotation difference between the first hoisting drum rotation axis and the second @ upper drum rotation axis of both clubs, and converts the inverter into an inverter. Since the control frequency is controlled, the hook level of both clubs can be more reliably maintained horizontally compared to the conventional method in which control is performed by increasing or decreasing the secondary resistance of a wound motor.

[Brief explanation of drawings]

The drawing is a schematic diagram showing an example of a device for carrying out the crane co-suspension uniform speed control method of the present invention. 1...First club hoisting drum 2...Second club hoisting drum 3...First inverter control device 4...
Second inverter control device 5...First synchro transmitter 6...Second synchro 5! ! Telephone 7...
Differential receiver Ml...first motor M2...second motor

Claims (1)

[Claims] When carrying out hanging work with two clubs, the hook level of both clubs is detected by a synchronized transmitter and a differential receiver installed on the respective hoisting drum rotation shafts of both clubs, and the hook level of each club is detected. A crane co-suspended speed control method characterized by increasing/decreasing the frequency of inverter control of a motor to equalize the level of both clubs.