JPS5815437B2 - Twin crane width control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a jib tip position control device for a twin jib crane.

Fig. 1 is a schematic diagram of a conventional twin jib crane. In the figure, 1 is a fixed post, 2 is a common swivel base that is rotatably mounted on the fixed post 1, and has a swivel inside. Built-in drive unit.

3 and 3' each have a hoisting device, an elevating device, and a turning device inside, and are two swing-type cranes mounted on the common swivel platform 2; 4 is a hoisting machine rope of each crane; 5 is the hoist block, 6 is the hoisting machine hook, and 7 is the hoisting machine hook 6
8 is a hook attached to the common hanging bracket 7, and 9 is a swing arm of each crane that can be raised and lowered.

The twin jib crane constructed as described above can normally be operated independently on the common swivel platform 2 by removing the common hanging fitting 7 from the hoisting machine hook 6, and is used as two cranes.

When handling a load that exceeds the lifting capacity of a single crane, use the condition shown in Figure 1 and suspend the load from the hook 8 to use it as a crane with twice the lifting capacity of a single crane. It is possible.

In this case, the hoisting device and elevating device of each crane 3, 3' can normally be operated synchronously from one of the crane cabs.

The swing drive device operates a swing drive device built into the common swing base 2, and the swing drive device of each crane 3.3' is fixed by a brake attached to the swing drive device.

Also, the dimension A between the tips of the swing arm 9 is equal to the distance between the centers of each crane 3, 3', and the line connecting the center of the tip of the swing arm and the center of the crane is perpendicular to the line connecting the centers of each crane 3, 3'. It is common practice to fix the swing drive in each crane 3, 3' at a location where the cranes intersect.

Therefore, if the angles of depression and elevation of the swing arms 9 of each crane 3, i3' are equal, the end dimension A of the swing arms is kept constant.

On the other hand, the dimension B between the common hanging fittings 7 is equal to the dimension A, so that the hoisting machine rope 4 is always vertical.

Therefore, in the state shown in Figure 1 (hereinafter referred to as twin crane operation), the hook 8 can hang a load equal to the lifting capacity of two cranes minus the weight of the common lifting fitting 7 and the hook 8. It is possible.

If the length B between the common hanging fittings 7 is not equal to the dimension A, the hoisting machine rope 4 will not be vertical and in order to hang the load from the hook 8 in this state, excessive force will be applied to each part of the crane. In order to avoid this, it is necessary to reduce the load by a considerable amount compared to the above.

Since the conventional device is configured as described above, the lengthwise dimension B of the hanging fitting is regulated by the dimension A, and therefore by the center-to-center dimension of the crane, and lifting and unloading of cargo in a narrow space is restricted.

Especially in the case of twin cranes installed on cargo ships, this was a fatal flaw when handling containers.

This invention was made with the aim of solving the above-mentioned conventional drawbacks, and by controlling one or both of the swinging devices when operating twin cranes, it is possible to avoid reducing the performance during twin crane operation. The present invention provides an automatic baggage device that can lower and unload cargo into narrow spaces by reducing the size of the hanging fittings to a wider width than conventional ones.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic side view of the twin crane, in which parts that are similar to those in FIG. 1 are designated by the same reference numerals.

Further, in FIG. 2, ro is the maximum cargo handling radius, and θLO represents the angle formed between the swing arm 9 and the horizontal plane (hereinafter referred to as the elevation angle).

rI is the minimum cargo handling radius, and the elevation angle at this time is θLI
Indicated by

Figure 3 is a top view of the state shown in Figure 2, where A is the center-to-center dimension of the crane 3.3', C is the dimension between the tips of the swing arms 9, and θ8o is the crane angle at the maximum cargo handling radius. Turning angle, θ
SI indicates the turning angle of the crane 3' at the minimum cargo handling radius.

X indicates the center of rotation of the common swivel base 2.

In FIG. 4, the horizontal axis shows the cargo handling radius, that is, the horizontal distance between the hook 6 of the crane 3 and the center of the main body, and the vertical axis shows the swing of the crane 3' when the horizontal distance C between the tips of the swing arms 9 is kept constant. The angle and the elevation angle difference between the cranes 3 and 3' are shown to make the line connecting the ends of the swinging arms and the line connecting the centers of the cranes parallel when viewed from above/surface.

The turning angle of crane 3' between ro and rI is θs1
The elevation angle of crane 3 is θL1゜3', and the elevation angle of crane 3 is θL2
shall be.

It should be noted that normally three crane sharpeners with the same dimensions are used.

Next, θS and θL2−θL1 in FIG. 4 will be determined.

Now, if the length of the swing arms 9 of the cranes 3 and 3' is r1 and the distance between the center of the main body and the hook 6 of the L1 crane 3 is r1, that of the crane 3' is r2, then the following holds true.

That is, if A, C, and L dimensions are given, θS and θL2−
θL1 is determined only by the cargo handling radius.

Also, the cargo handling radius and the elevation angle of the crane 3, r1 = L cos
θL.

Since there is a relationship, θS is also θL2 with only the elevation angle θL1.
-θL1 is also determined.

FIG. 5 is a block diagram showing an embodiment of the present invention based on the above principle.

In FIG. 5, reference numeral 21 denotes an elevation angle signal generating section of the crane 3, which detects, for example, an elevation angle θL1 of the swing arm 9 using a potentiometer.

22 is a swing angle signal generator configured to output the swing angle θS of the crane 3' according to the above formulas (1) and (3); 23 is a swing angle detection signal generator for the crane 3'; and 24 is a swing angle signal generator configured to output the swing angle θS of the crane 3'. A swing angle comparator, 25 is a swing drive control device for the crane 3', 26 is an input signal of the elevation angle signal θL1 from the elevation angle signal generator 21, and the equations (1) and (5) are
), an elevation angle difference signal generator configured to output an elevation angle difference θL2−θL1; 27 is a crane 3;
28 is a differential synchro receiver that responds to the elevation angle of the swing arm 9 of the crane 3; 29 is a differential synchro transmitter that detects the elevation angle of the swing arm 9 of the crane 3; A synchro converter converts the angle difference of the receiver 28 into a signal, 30 is an elevation angle difference comparator, and 31 is a control device for the elevation device of the crane 3'.

To explain the operation shown in FIG. 5, the elevation angle signal generator 21
The .theta.L1 signal from the .theta.L1 signal becomes an input signal to the turning angle signal generator 22, and the turning angle signal generator 22 generates a turning angle .theta.S signal.

This θS signal is compared with the swing position signal of the crane 3' from the swing angle detection signal generator 23 in the swing angle comparator 24, and a signal is sent to the swing drive control device 25 so that the deviation is approximately 0. The pivoting position of the crane 3' is controlled by this.

Furthermore, the elevation angle difference between the cranes 3 and 3' is detected by an elevation angle difference detection device consisting of a differential synchronization transmitter 27, a differential synchronization receiver 28, and a synchronization converter 29 that converts the angle difference between these input shafts into a signal. This detection signal is compared with the signal from the elevation angle difference signal generator 26 by an elevation angle difference comparator 30.

Based on the output of this elevation angle difference comparator 30, the crane 3'
The control device 31 of the elevating device is driven, and the elevating angle of the crane is controlled so that the deviation becomes zero.

Note that an analog function generator using an approximate broken line can be used as the turning angle signal generator 22 and the elevation angle difference signal generator 26 in the above embodiment.

As is clear from the above explanation of the operation, when the elevating device of the crane 3 is operated, the swinging and elevating of the crane 3' are automatically controlled, and the distance between the jib tip and The line connecting the ends can be viewed from above and kept parallel to the line connecting the center line of the crane.

At this time, when the height of the tip of the swinging arm is not the same and the height is not the same, cranes are normally operated with horizontal retraction, in which the lifting fitting moves almost horizontally, and there is no practical problem at all.

'Although the above embodiments show simultaneous control of turning and elevation, even controlling only turning has considerable practical benefits.

In addition, potentiometers are used to detect rotation and elevation angles.
Although the differential synchronizer is used as an example, other angle detection devices can be used as appropriate.

The elevation angle can also be detected from the rotation of the drum of the elevation winch.

As described above, according to the present invention, the tip of the swinging arm is automatically moved around the edges, so there is no need for special lifting equipment, and the ability of the crane is not reduced, making it possible to move loads into narrow spaces. A twin crane capable of lifting and unloading can be obtained.

For example, it is possible to set the end of the swing arm to be larger than the center-to-center dimension of the crane, and it can also be applied to transporting long objects, which has great practical effects.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional twin crane, Fig. 2 is a surface survey of the twin crane for explaining the present invention, Fig. 3 is a top view of Fig. 2, and Fig. 4 is a cargo handling radius. FIG. 5 is a block diagram of a control device according to an embodiment of the present invention. In the figure, 1 is a fixed post, 2 is a common swivel base, 3.3' is a jib-type rotating crane, 4 is a hoisting machine rope, 5 is a hoist block, 6 is a hoisting machine hook, 7 is a common hanging bracket, 8 9 is a hook, 9 is a swivel arm, 10 is a winding rope, 11 is a lifting device, 21 is an elevation angle detector, 22 is a swivel angle signal generator, 23 is a swivel angle detector, 24 is a comparator, 25 26 is an elevation angle difference signal generator, 27 is a differential synchro transmitter, 28 is a differential synchro receiver, 29 is a signal converter, 30 is a comparator, and 31 is an elevation control device. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. In a twin jib crane, an elevation angle detection device that detects the elevation angle of the swing arm of one crane serving as a reference, a swing angle detection device that detects the swing angle of the swing arm of the other crane, and the above-mentioned A swing angle command device is provided for commanding a swing angle of the swing arm of the other crane based on a detection signal of the elevation angle detection device, and a command value of the swing angle command device is compared with a detection value of the swing angle detection device. and controlling the rotation device of the other crane so that the deviation between the two becomes 0,
A width control device for twin cranes, characterized by keeping the horizontal distance between the tips of the swinging arms of both cranes constant regardless of the elevation angle. 2. In a twin jib crane, an elevation angle detection device that detects the elevation angle of the swing arm of one crane that serves as a reference, a swing angle detection device that detects the swing angle of the swing arm of the other crane, and detection of the elevation angle detection device described above. a swing angle command device that commands a swing angle of the swing arm of the other crane based on the signal; a swing angle difference detection device that detects a difference in elevation angle between the one crane and the other crane; and a detection device that detects the elevation angle. comprising an elevation angle command device that commands the elevation angle difference between the two cranes based on the detection signal of the device;
Compare the command value of the turning angle command device and the detection value of the turning angle detection device, and the command value of the elevation angle command device and the detection value of the elevation angle difference detection device, and each comparison deviation becomes O. By controlling the swinging device and the elevating device of the other crane, the horizontal distance between the tips of the swinging arms of both cranes is maintained constant, and a line connecting the tips of the swinging arms and a line connecting the swinging centers of both cranes is maintained constant. A width control device for a twin crane, characterized in that the width of the crane is made parallel to each other.