JPS5926599B2 - Steady rest control device for crane with jib - Google Patents

Description

[Detailed Description of the Invention] This invention is a crane with a jib, such as a Derrick crane or a climbing crane, which prevents the load from being carried when hoisting a load and cutting the ground due to the deflection of the jib due to the load of the hoisted load. The present invention relates to a steady rest control device.

Conventionally, the lifting and lifting controllers were manually operated during hoisting, depending on the experience and intuition of the crane operator, to deal with the lifting of a load that occurs when a crane with a jib, such as a Derrick crane or a climbing crane, loses its load. A good combination of retractions prevented the load from being carried during the ground cutting.

For this reason, the degree of load-carrying has to depend on the skill level of the driver, and it has been difficult to reliably prevent load-carrying.

In addition, in order to reduce the deflection of jibs, posts, etc., which can cause load carrying, structural members had to be made larger than necessary.

In particular, compared to other jib-equipped cranes, climbing cranes tend to have larger deflections due to their structure, and the working moment tends to become more dog-shaped, so it automatically prevents the load from being lifted when the load is cut off. It was desired to do so.

In view of the above-mentioned situation, the inventors of the present invention have conducted extensive research and have come up with the present invention. It is possible to automatically control the crane's steady rest by giving the amount of retraction corresponding to the
To provide a crane steady rest control device which enables a crane to follow-up operation by interlocking hoisting and retracting operations without operating a retracting controller during hoisting operation.

Another object of the present invention is to minimize the deflection of the jib, post, etc. that causes loading, so that the structural members of the entire device can be simplified and downsized. In addition, the present invention provides a crane steady rest control device that can automatically control load carrying, can be operated without requiring the experience or intuition of a crane operator, and can ensure safety for ground workers.

Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the load swing that occurs when unloading a load with a crane with a jib.

In Fig. 1, when tension is applied to the hoisting rope of the jib 2 before hoisting the suspended load 1, the jib flexes as shown at 2' and 2'', and the post 3 also flexes, causing the jib to flex. The tip moves forward.

When the amount of deflection of the jib due to hoisting reaches an amount commensurate with the load of the suspended load 1, the suspended load 1 breaks, and at that moment, the suspended load 1 suddenly moves horizontally in the direction of the arrow to prevent the load from swinging. arise.

In order to prevent this load from swinging, as hoisting begins and tension is applied, the tip of the jib moves forward by pulling in the jib, so that the suspended load 1 is always on a perpendicular line from the tip of the jib. By controlling the load so that it is possible to prevent the load from swinging when cutting off the ground.

Therefore, the steady rest control device of the present invention detects the load of the suspended load 1 before it cuts the ground, and drives the jib by an amount of movement commensurate with the amount of deflection of the crane from the moment of the jib in the jib radius at that time. After raising the ground, perform the ground cutting.

In this case, if the jib is suddenly raised just before the jib is pulled up, the amount of deflection at that time will be reduced, and the suspended load 1 will be lifted off the ground before the jib is raised by the necessary amount of movement.

Therefore, at the same time as hoisting of the suspended load 1 is started, the amount of movement is determined from the amount of deflection corresponding to the moment obtained by detecting the suspended load load and the jib radius, and a retraction operation that follows the hoisting is started.

In addition, the time required for the retracting operation performed at a predetermined speed is relatively long compared to the time required for breaking the ground during hoisting.
They tend to be late.

Therefore, the hoisting speed up to the ground cutting is set to a predetermined low hoisting speed that is lower than the hoisting speed during operation and that allows the retracting operation to sufficiently follow.

However, since high-speed hoisting is required after ground breaking, the system detects that ground breaking occurs and automatically switches to the hoisting speed corresponding to the set speed of the hoisting controller.

FIG. 2 is a block diagram showing an embodiment of the steady rest control device of the present invention.

In FIG. 2, drive control of the hoisting motor M1 includes a hoisting controller 4, a hoisting speed command device 5, a speed controller 6,
The starting torque command device 7, the current controller 8, and the SiRisk control device 9 perform phase gate control of 5 CRI.

Hoisting control during steady rest control in the hoisting motor control unit composed of these can be performed by switching the manual/automatic selection switch of the hoisting controller 4 to the automatic side, and the relay contact 4-1
opens, the relay contact 5-1 closes, and the speed command signal of the specified bottom speed from the hoisting speed command device 5 reaches the addition point 6-
Feedback control is performed using the deviation from the detection signal of the tacho generator TG, which is supplied to the motor M1 and detects the rotational speed of the hoisting motor M1 by a speed controller 6 comprising an operational amplifier.

During this speed control, the current value that provides the required starting torque to the electric motor M1 is determined by current control using an operational amplifier based on the current command value from the starting torque command device 7 that provides a command pattern that increases stepwise and changes over time. In the device 8, the deviation from the output of the CTI that detects the drive current of the hoisting motor is obtained at the addition point 8-1, and the starting torque current based on the current command value is controlled by the gate phase control of the hoisting motor M1.
is supplied to.

On the other hand, drive control of the retracting electric motor M2 is performed by using a retracting controller 10, a load detector 11 such as a load cell that detects the mold of the suspended load, a radius detector 12 such as a cersin that measures the radius of the jib, and a detected load and jib. a moment detector 13 that provides a moment that is multiplied by the radius, and a deflection amount indicating device 1 that provides a deflection amount indicating signal based on a characteristic curve of the amount of deflection with respect to a predetermined moment according to the specifications of the crane.
4. The speed at which the jib is retracted by a specified amount is determined by the follow-up speed command signal given from the current control reference signal of the hoisting motor control unit via the variable resistor VR for adjustment and the command signal from the deflection amount command device 14. This is carried out by a retracting electric control section which includes a retracting amount command device 15 which provides a reference signal, a speed controller 16 comprising an operational amplifier, and a silisk control device 19 which performs gate phase control of the current controller 18.5CR2.

To explain the steady rest control operation in this electric control unit for pulling, when hoisting control is started, the load of the suspended load and the radius of the jib are detected by the load detector 11 and the radius detector 12.
The moment detector 13 calculates the moment of the jib, and from this moment signal the deflection amount indicating device 1
4 gives a deflection instruction signal generated in the jib in real time to the retraction amount command device 15.

On the other hand, the retraction amount command device 15 is supplied with a follow-up command signal from a variable resistor VR that provides a current control reference signal for the hoisting motor control section at a predetermined ratio.

The follow-up command signal from the hoisting motor control unit that is applied to the retraction amount command device 15 via the variable resistor VR is a speed signal that determines at what speed the specified retraction amount of the jib 2 obtained from the amount of deflection is to be retracted.

That is, although the specified amount of retraction can be obtained from the deflection amount indicating device 14, the retraction speed cannot be obtained because the element of time is not included.

Therefore, it is necessary to determine the retraction speed.

If the retraction speed is set low even though the hoisting speed is fast, the amount of retraction will be insufficient and the forward movement of the tip of the jib 2 cannot be completely corrected, resulting in load swing when cutting off the ground.

On the other hand, if the retracting speed is set high even though the hoisting speed is low, the hoisting rope will become loose and the amount of deflection will decrease, and before the jib can be retracted by the required retracting amount, jib 2 will be raised significantly and the rope will be suspended. This causes the inconvenience that the load 1 is cut off.

In order to eliminate these inconveniences, the retracting speed is controlled to follow the hoisting speed by obtaining a signal from the hoisting motor control section.

Then, a speed reference signal for pulling in a specified amount obtained from the amount of deflection is sent to an addition point 16-1 via a relay contact 15-1.
The speed controller 16 performs feedback control based on the deviation from the output signal of the tacho generator TG which provides the rotational speed of the retracting electric motor M2.

In addition, the current controller 18 that controls the current value that gives one drive torque to the retracting motor M2 feeds back the detection signal of Cr2 that detects the control current of 5CR2 to the addition point 18-1 to detect the deviation from the current control reference signal. Feedback control is performed by

Note that during the steady rest control of the present invention, the manual/automatic selection switch of the retraction controller 10 is switched to the automatic side, thereby opening the relay contact 10-1 and closing the relay contact 15-1. Of course.

As explained above, the crane steady rest control device of the present invention calculates the amount of deflection of the jib from the load of the suspended load and the actual measured value of the radius of the jib, and calculates the amount of retraction of the jib based on this amount of deflection to the steady state of the hoisting motor. The retracting motor is controlled by a speed reference signal that follows a specified hoisting reference speed lower than the hoisting speed, thereby making it possible to minimize the swing of the suspended load that occurs when the load is cut off the ground.

Therefore, it is not necessary to operate the retraction controller during hoisting operation as in the past, and the linked follow-up operation of hoisting and retraction operations is performed automatically, greatly reducing the burden on the driver. In addition, the control of the starting torque of the hoisting motor in steady rest control uses a program command that rises in steps and changes over time, so the starting torque of the hoisting motor that causes the ground breaking is created in one of the steps, and suddenly 1. There is no ground breaking due to over-torque or jump-up due to torque accumulation. This makes it possible to minimize the amount of load swing at the time of cutting off the ground.

Furthermore, since the present invention can minimize the deflection of the jib or post, etc., which causes load swing, the entire device can be downsized and provided at low cost. By adapting the crane to various types of jib-equipped cranes such as the above, the crane can be operated without requiring the operator to have special skills for preventing load swing, and the load swing can be reliably prevented, improving the safety of crane work. The practical value is enormous, as it can increase the energy consumption and exhibit extremely excellent effects.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram illustrating the deflection of the jib and the swing of the suspended load that occur when hoisting a crane with a jib to the ground, and Fig. 2 is a block diagram showing an embodiment of the crane steady control device of the present invention. . In the figure, 1 is a suspended load, 2, 2', 2'' are a jib, 3 is a post,
4 is a hoisting controller, 5 is a hoisting speed command device, 6, 1
6 is a speed controller, 6-1.8-1゜16-1.18-1
is an addition point, 7 is a starting torque command device, 8, 18 is a current controller, 9.19 is a silisk control device, 10 is a retraction controller, 11 is a load detector, 12 is a radius detector, 13
is a moment detector, 14 is a deflection amount support device, 15 is a retraction amount command device, 4-1, 5-1.10-1.15-1
is a relay contact, Ml is a hoisting motor, Ml is a pulling motor, TG is a tacho generator, and VR is a variable resistor.

Claims (1)

[Claims] 1. A starting torque command device that issues a starting torque command that rises in steps and changes over time in accordance with the deviation between the hoisting speed command and the detected speed of the hoisting drive source of the crane, and a starting torque command that is based on the starting torque command of the command device. A drive device that drives and controls the hoisting drive source, a deflection amount indicating device that indicates the amount of deflection of the jib according to the moment of the jib, and the hoisting drive based on the amount of deflection of the indicating device and the starting torque command. a retraction amount command device that obtains the retraction amount of the jib following the drive control of the jib source; and one drive source for retraction according to the deviation between the amount of retraction of the jib of the retraction amount command device and the detected speed of the drive source for retraction of the jib. A steady rest control device for a crane with a jib, comprising: a drive device for controlling the drive of the crane; .