JPH0940368A - Steel plate grasping position detecting device in slab conveying crain - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a trouble such as dropping a slab in the conveying condition, by providing a grasping position operator to detect either the rotating angle of a rotary shaft or the driving amount of a driving device, and to find the slab grasping position by a clamping claw, from the above detecting information. SOLUTION: A rotating angle β is subtracted from a grasping angle γ, and the front end position of a rotary claw 12 contacting to the lower surface of a slab 1c, and the angle θ to the horizontal line Z are found. Depending on the angle θ, the laying margin K of a crain tongue 6 to the slab 1c is found. In a grasping position controller 4, the laying margin K input to the controller 4 is compared with a standard scope value k input from a setting unit 3, and when the laying margin K is within the standard scope k, the conveying is carried out by hanging as it is, and when the laying margin K is out of the standard scope k, the grasping slabs 1a to 1c are returned to the original positions, and the grasping is repeated to make the laying margin K within the standard scope k.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a tong type crane,
The present invention relates to a device for detecting a slab gripping position in a slab transfer crane such as a lifter type crane.

[0002]

2. Description of the Related Art Generally, a slab-conveying crane, such as a tong crane, which pushes a claw of a lifting tool against a side surface of stacked slabs and lifts and transports the slab is a claw for sandwiching the slab from the cab position of the crane. Since it is difficult to detect whether the tongue claws are hooked at the appropriate gripping position on the side surface of the slab, check the condition of the tong claws (hereinafter simply referred to as "tongs") and ask the crane operator. It was necessary to assign a ground worker to send a signal.

However, such a conventional slab gripping tongue is not labor-saving in terms of its operation, and it takes a lot of time to engage the tongue at a desired slab position, and it is not preferable in terms of safety for a ground worker. . For this purpose, for example, in Japanese Patent Laid-Open No. 123096/1990, a tongue is provided with a slab shape recognizing device such as an ultrasonic range finder, and the slab shape recognizing device is used to lift the end of the stacked slab to be lifted while the tongue is descending. There has been proposed a method of recognizing a shape of a part, detecting a boundary surface of a stacked slab, and detecting a gripping position of the slab based on the boundary surface.

[0004]

However, the method disclosed in Japanese Patent Laid-Open No. 123096/1990 has the following disadvantages and is not always sufficient. . Since ultrasonic waves are used as the slab shape recognition device, the structure is complicated and expensive, and moreover, frequent maintenance is required. . It is weak against impact such as when the tongs touch the ground and radiant heat from the hot slab, and its reliability is low. . Since the end shape of the stacking slab is measured while the tongs are descending, if the tongs sway during the descending, a measurement error will occur.

In such a state, it is not guaranteed that the proper position of the slab is grasped by the crane tongs within a limited time, and there is a problem that a serious trouble such as dropping the slab during transportation occurs. The present invention has been made in view of such a problem, is inexpensive and has good maintainability, accurately detects the gripping position of the slab with the tongs, and prevents problems such as falling of the slab during conveyance. Is an issue.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the means is to hold and suspend a plurality of slabs by a sandwiching claw of a slab-conveying crane in a stacked state. In the device for detecting the slab gripping position by the sandwiching claw when conveying to a predetermined position, a rotating shaft is rotatably provided under the sandwiching claw and a driving device for driving the rotating shaft is provided, and the sandwiching is performed. The rotary shaft is provided with a rotary claw capable of contacting the bottom surface of the lowermost slab that is grasped and suspended by the claw,
Further, when the rotary claw comes into contact with the suspended lower surface of the slab, either the rotation angle of the rotary shaft or the drive amount of the drive device at this time is detected, and the slab grip by the sandwiching claw is detected based on this detection information. It is a slab grip position detection output device in a slab transfer crane provided with a grip position calculation unit for obtaining a position. As the drive device, a motor, a cylinder or the like having a self-detection function of a rotational position or a slide position is used.

[0007]

First, the outline of the position detection of the present invention will be briefly described. In order to convey several pieces of the upper stacking portion of the slabs stacked in multiple stages at one time, the lowermost piece of the slab to be lifted is to be conveyed. The sides of must be held in place. Since that position is located almost in the center of the slab thickness, in order to confirm this position, the temporary position is determined by the weight hanging at the top of the slab, and the temporary suspension is carried out on that tongue position that holds the slab. Is confirmed, and an operation for ensuring safety is provided to shift to the next work depending on whether or not the position is within the reference value.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3 by taking a tong type crane as an example. FIG. 1 is a system structure diagram of an embodiment, in which 1a to 1f are multi-tiered slabs, 2 is a height meter for detecting the upper surface position of the uppermost slab, and a wire having a weight 2b at its tip. Two
c, a stepping motor 2a for winding and lowering the wire 2c, and a height calculation 2d for estimating and calculating the height from the weight 2b based on the rotation speed of the stepping motor 2a.

Further, 3 is a gripping slab setting device for instructing the gripping position control unit 4 as to how many slugs the crane tongs 6 count from the uppermost slab, and 5 is a bottom end of the slab that is operated after ground cutting. A gripping position calculation unit for detecting the position, and 7 are slabs 1a to 1 input from a host computer (not shown).
The slab information processing unit 8 that stores the thickness information of f is a rotating shaft rotatably provided on the side surface of the crane tong 6, and is rotated by the stepping motor 10 via the toothed belt 11. Reference numeral 12 is a fishing hook-shaped rotating claw whose one end is fixed to the rotating shaft 8.

Next, the operation of hoisting the three slabs 1a to 1c from the piles stacked in multiple stages by the crane tongs 6 will be described. First, the crane tongs 6 are lowered, the stepping motor 2a is driven to lower the weight 2b, and the upper end level of the uppermost slab 1a is detected by the height calculator 2d from the rotation speed of the stepping motor 2a. The detected upper end level information of the uppermost slab 1a is input to the grip position control unit 4 and the thickness information of the slabs 1a to 1c is input from the slab information processing unit 7, and the center of the slab 1c is input based on this information. Then, the height of the crane tongue 6 is set so that the grip portion 6a of the tongue 6 comes.

However, when the height of the crane tongs 6 is set to a predetermined position, the crane tongs 6 are used to set the slab 1
Grab c and wind up the crane tongs 6 to a predetermined height (about 0.3 to 0.5 m) to cut the slab 1c. (FIG. 3) After the ground cutting, the grip position control unit 4 drives the stepping motor 10 via the grip position calculation unit 5 and sequentially inputs the number of rotations from the start of driving to the stop. After that, this stepping motor 10
In response to an instruction from the gripping position control section 4, starts rotating and rotates the rotary claw 12 in the direction of arrow A, and the slab 1c
Touch the bottom surface of. Then, when the rotary claw 12 comes into contact with the lower surface of the slab 1c, the load applied to the stepping motor 10 increases and the stepping motor 10 stops. Next, this time, the stepping motor 10 rotates in the opposite direction to rotate the rotary claw 12 in the direction of the arrow B, return to the original standby position, and stop.

On the other hand, the gripping position calculator 5 rotates from the start to the stop of the stepping motor 10 (rotational speed while the rotating claw 12 is rotating in the direction of arrow B).
Then, the rotation angle β of the rotary claw 12 is calculated. Further, when the crane tongs 6 grip the slab 1c, the gripping portion 6a
Draws a circular arc, the gripping angle γ determined by the width dimension of the slab 1c (the angle between the tip position of the rotary claw 12 at the standby position and the horizontal line Z passing through the rotary shaft 8) is the width dimension of the slab 1c to be gripped. (When the width dimension of the slab 1c is long, the grip angle γ is large, and when the width dimension of the slab 1c is short, the grip angle γ is small). Then, the rotation angle β is subtracted from the grip angle γ to obtain the angle θ up to the horizontal line Z and the tip position of the rotary claw 12 that contacts the lower surface of the slab 1c.

Based on this angle θ, the hanging margin K of the crane tongue 6 on the slab 1c is determined by the following equation (1), and is input to the grip position control section 4. K = a + (t-lsin θ) (1) where a: distance from the center of the rotating shaft 10 to the center Q of the tongue tip t: thickness of the slab 1c l: length of the rotating claw 12

In this way, the grip position control section 4 compares the input allowance K with the reference range value k input from the setter 3, and if the allowance K is within the reference range value k, it is as it is. Lift and transport. On the other hand, if the hanging allowance K is outside the reference range value k (when the gripped position is out of the vicinity of the center of the slab side surface), the held slabs 1a to 1c are returned to their original positions, and the hanging allowance K is the reference range. Re-grab so that it is within the value K.

The above embodiment is the case of the crane tongue 6, and at this time, the gripping angle γ is calculated based on the width dimension of the slab 1c to be gripped, but in the case of the lifter type crane, When the lifter grips the slab, the lifter does not make a circular motion but a parallel motion, and therefore has a constant value regardless of the width dimension of the slab 1c. Others are the above crane tongs 6
Is the same as

Further, the above embodiment is an operation example in the case of gripping three slabs, but the operation principle is exactly the same even if the number of slabs is increased or decreased. Further, in this example, the rotation amount is detected by the stepping motor, but when a general motor is used instead of the stepping motor, a tachometer is provided on the rotary shaft 8. Furthermore, when a cylinder is used instead of a motor as a drive device, the drive amount of the cylinder (the operation stroke amount of the cylinder rod) is measured, and the angle β of the rotary pawl 12 is calculated. In the practice of the present invention, since the slab position is predicted in advance, re-grabbing of the slab with the crane tongs is extremely rare.

[0017]

As described above, according to the present invention, it is possible to accurately and reliably detect the gripping position of the slab by the clamping jaws of the slab conveying crane such as the tong type crane and the lifter type crane. It is possible to completely prevent the slab from falling and to greatly contribute to the unmanned slab transfer crane.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a system according to this embodiment.

FIG. 2 is a view on arrow I-I of FIG.

FIG. 3 is a diagram for explaining an example of calculating a tong hanging allowance.

[Explanation of symbols]

 1a to 1f Slab 2a Tepping motor 2b Weight 2c Wire 2d High calculation part 3 Setting part 4 Gripping position control part 5 Gripping position calculation part 6 Tongs 6a Gripping part 7 Slab information processing part 8 Rotating shaft 10 Stepping motor 11 Belt 12 Rotating claw

Claims (1)

[Claims] 1. A device for detecting a slab gripping position of a sandwiching claw when gripping a plurality of slabs with a sandwiching claw of a slab transporting crane in an overlapping state and suspending and transporting the slab to a predetermined position. A rotary shaft is rotatably provided under the sandwiching claw, and a drive device for driving the rotary shaft is provided. The rotary shaft is provided with a rotary claw capable of contacting the lower surface of the lowermost slab held by the sandwiching claw and suspended. Further, when the rotary claw comes into contact with the suspended lower surface of the slab, either the rotation angle of the rotary shaft or the drive amount of the drive device at this time is detected, and the slab at the sandwiching claw is detected based on this detection information. A slab gripping position detection device for a slab transfer crane, which is provided with a gripping position calculation unit for obtaining a gripping position.