Track-traveling crane

Abstract

To provide a track-traveling crane capable of maximizing lifting capacity during work.SOLUTION: A track-traveling crane 1 that is provided with legs 9 having a plurality of running wheels 10 that can roll freely along rails 2, on a running body 3, and travels on the rails 2 using the running body 3 to perform loading and unloading operations, is equipped with a wheel pressure detector that detects the wheel pressure acting on each running wheel 10 of the legs 9, and a control device that controls the tilting angle and swivel angle of a jib 6 so that they do not exceed their limits in order to ensure stability during work, and in parallel with this control, monitors the wheel pressure detected by the wheel pressure detector to ensure that it does not exceed the allowable wheel pressure of the foundation.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a track-traveling crane. [Background technology]

[0002] Generally, track-traveling cranes are installed in docks where ships are built. This type of track-traveling crane has a running body that runs freely along rails laid on a foundation, a rotating body that is rotatably arranged on the top of a post that is erected on the running body, and a jib that can be raised and lowered on the rotating body.

[0003] A prerequisite for installing this type of track-traveling crane is the allowable wheel pressure that the foundation can withstand. For example, if the track-traveling crane's running body has legs on the front, back, left, and right sides, and the crane is rotated so that the jib faces the diagonal of the rectangle connecting the legs, and then the jib is lowered to a certain angle (maximum moment generating state) while lifting the maximum load in this state, it is known that a maximum wheel pressure will be generated on one of the legs arranged in that diagonal direction, and care must be taken to ensure that the maximum wheel pressure generated under these conditions does not exceed the allowable wheel pressure of the foundation.

[0004] For this reason, conventionally, the maximum wheel pressure generated under the conditions described above has been designed to be below the allowable wheel pressure of the foundation, while the jib lowering angle under the conditions where the maximum wheel pressure occurs has been set as the lowering limit. Even though the wheel pressure differs depending on the direction of the jib (swing angle), the swing angle has been ignored and only the jib lowering angle has been controlled so as not to exceed the lowering limit, thereby ensuring the stability of the track-traveling crane during operation.

[0005] Incidentally, for example, Patent Document 1 shows the general state of the art related to the track-traveling crane. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-11734 Summary of the Invention [Problem to be solved by the invention]

[0007] However, if a lowering limit were set in this way and only the jib lowering angle were controlled, the working range would be limited to a circle with a working radius determined by that lowering limit, resulting in the same allowable lifting load at all rotation angles.For example, if the jib of a track-traveling crane is rotated so that it faces the diagonal of the rectangle connecting the legs of the crane, and then the jib is rotated further so that it faces parallel to the rails, the wheel pressure on the foundation will be reduced, resulting in a limit being imposed on the potential for increasing the lowering angle and load.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a track-traveling crane that can maximize the lifting capacity during work. [Means for solving the problem]

[0009] The present invention provides a track-traveling crane having a running body with legs having a plurality of running wheels that can roll freely along a rail, and the running body travels on the rail to perform loading and unloading work, This relates to a track-traveling crane equipped with a wheel pressure detector that detects the wheel pressure applied to each running wheel of the leg, and a control device that controls the jib's lowering angle and rotation angle so that they do not exceed their limits in order to ensure stability during work, and in parallel with this control, monitors the wheel pressure detected by the wheel pressure detector so that it does not exceed the allowable wheel pressure of the foundation.

[0010] In addition, in the present invention, it is preferable that the control device is configured to continue the lying operation or slewing operation until the jib lying angle or slewing angle reaches its limit as long as the wheel pressure does not reach the allowable wheel pressure of the foundation, while stopping the lying operation or slewing operation when the wheel pressure reaches the allowable wheel pressure of the foundation even if the jib lying angle or slewing angle has not reached its limit.

[0011] Furthermore, it is preferable that the control device be configured to be equipped with a rotation angle detector that detects the rotation angle of the jib, a lowering angle detector that detects the lowering angle of the jib, and a load load detector that detects the load of the load lifted by the jib, and to perform control to ensure stability during work based on these detected values.

[0012] In addition, a wheel pressure detector may be installed at the pivot point of the leg relative to the running body, the load detected by the wheel pressure detector may be input to the control device as a detected value, and the wheel pressure may be calculated by dividing the detected value by the number of wheels per leg. [Effects of the Invention]

[0013] With the track-traveled crane of the present invention, rather than setting the jib lowering angle at the time when maximum wheel pressure is generated as the lowering limit, wheel pressure detectors are used to constantly measure and monitor whether the wheel pressure exceeds the allowable wheel pressure of the foundation, and control is performed based on the stability of the track-traveled crane within a range where the wheel pressure does not exceed the allowable wheel pressure of the foundation. Therefore, unlike in the past when a lowering limit was set and only the jib lowering angle was controlled, when the jib is rotated so that it faces the diagonal of the rectangle connecting the legs of the track-traveled crane, and then further rotated so that it faces parallel to the rails, the jib lowering angle and the load of the load can be made larger than before, providing the excellent effect of maximizing the lifting capacity of the track-traveled crane when in operation. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is an explanatory diagram showing an embodiment of a track-traveling crane according to the present invention. FIG. [Figure 2] 2 is an enlarged view showing details of the periphery of the leg in a lower side view of FIG. 1. FIG. [Figure 3] FIG. 2 is a block diagram of a control system according to an embodiment of the present invention. [Figure 4]FIG. 2 is a plan view showing details of a turning angle detector in the embodiment of the present invention. [Figure 5] FIG. 2 is a side view showing details of a tilt angle detector in the embodiment of the present invention. [Figure 6] 4 is a flowchart showing a control procedure in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0016] Figure 1 shows one embodiment of the track-traveling crane of the present invention, and is an explanatory diagram showing the relationship between the jib rotation angle and the working range when lifting the maximum rated load (as an example, the rated load: 120t is shown). The lower part of Figure 1 shows the track-traveling crane from a side view, and the upper part of Figure 1 shows the track-traveling crane (mainly showing only the parts related to travel) from a plan view.

[0017] The track-traveling crane 1 shown here is configured with a running body 3 that can travel freely along rails 2 laid on a foundation, a post 4 erected on the running body 3, a rotating body 5 arranged to be able to rotate freely at the top end of the post 4, and a jib 6 attached to the rotating body 5 so that it can be raised and lowered, and the running body 3 can travel on the rails 2 to perform loading and unloading operations.

[0018] As shown enlarged in Figure 2, the running body 3 is equipped with legs 9 consisting of multiple equalizer beams at the front and rear positions (see the plan view in the upper part of Figure 1) of running frames 7 provided on both the left and right sides of the running body 3 (see the illustration in the upper part of Figure 1), the middle part of the uppermost stage being pivoted by rocker pins 8 oriented perpendicular to the running direction, and the lowest equalizer beam of the leg 9 is equipped with a number of rolling running wheels 10.

[0019] However, in this embodiment, a pin-type load cell is attached to the rocker pin 8 that pivots each leg 9 relative to the traveling frame 7 as a wheel pressure detector 11, and as shown in FIG. 3, the load detected by this wheel pressure detector 11 is input as a detected value to the control device 12, and the wheel pressure is calculated by dividing the detected value by the number of wheels per leg 9.

[0020] Furthermore, the control device 12 also receives input of detection values ​​from a rotation angle detector 13 that detects the rotation angle of the jib 6, a lowering angle detector 14 that detects the lowering angle of the jib 6, and a suspended load detector 15. Based on these detection values, the control device 12 controls the lowering angle and rotation angle of the jib 6 during lowering and rotation operations so that they do not exceed their limits, thereby ensuring stability during work.As will be described in detail later, the wheel pressure is monitored in parallel with this control to ensure stability during work.

[0021] Here, as shown in a plan view in Figure 4, the rotation angle detector 13 is an encoder that detects the rotation angle of the jib 6, and is configured to detect the number of rotations of the pinion 17 (rotating side) that is meshed with the internal gear of the rotation bearing 16 (fixed side) of the rotating body 5.Since the number of rotations that the pinion 17 takes to make one revolution around the rotation bearing 16 is fixed, once a base point is determined, the direction of the jib 6 (rotation angle from the base point) can be detected from the number of rotations and direction of rotation of the pinion 17.

[0022] Also, as shown in the side view of Figure 5, the lowering angle detector 14 is a potentiometer that detects the lowering angle of the jib 6 and has the function of detecting the angle relative to the ground.By aligning the center axis of the jib 6 with the reference position of the lowering angle detector 14, the lowering angle of the jib 6 can be detected from the direction of rotation of the pivot shaft 18 at the base end of the jib 6.

[0023] The load detector 15 is a load cell that detects the load of the load being lifted by the jib 6, and is attached to a sheave (not shown) provided at the tip of the jib 6 or to a hoisting rope that is looped around the sheave.

[0024] Here, in the control by the control device 12 described above in Figure 3, the working range of the jib 6 is set based on the rotation angle of the jib 6 detected by the rotation angle detector 13, and as shown in the upper part of Figure 1, the working range of the jib 6 for the same load gradually increases as the rotation angle of the jib 6 approaches a direction parallel to the rail 2 from a direction perpendicular to the rail 2.

[0025] The reason for this is that the wheelbase W of the track-traveling crane 1 shown in Figure 1 is longer than the rail span S, and as the rotation angle of the jib 6 approaches a direction parallel to the rail 2 from a direction perpendicular to the rail 2, the track-traveling crane 1 becomes less likely to tip over and becomes more stable.

[0026] Furthermore, the control device 12 selects and applies an appropriate rated load curve depending on the rotation angle, and in any rated load curve, the rated load that can be lifted gradually decreases from the maximum value as the working range increases.

[0027] As shown in Figure 3, the control device 12 is connected to a rotation limiting mechanism 20, a lowering limiting mechanism 21, and a ground clearance limiting mechanism 22. For example, the rotation limiting mechanism 20 uses a rated load curve selected according to the rotation angle of the jib 6 detected by the rotation angle detector 13, and limits the rotation of the rotating body 5 by a control signal output from the control device 12 based on the lowering angle of the jib 6 detected by the lowering angle detector 14 and the load of the suspended load detected by the suspended load detector 15. Even if the jib 6 attempts to rotate in a direction that exceeds the rated load, its movement is limited, thereby maintaining the stability of the track-traveling crane 1 during operation.

[0028] In addition, the lowering limiting mechanism 21 uses a rated load curve selected according to the rotation angle of the jib 6 detected by the rotation angle detector 13, and limits the lowering of the jib 6 by a control signal output from the control device 12 based on the lowering angle of the jib 6 detected by the lowering angle detector 14 and the load of the suspended load detected by the suspended load load detector 15.Even if the working range becomes too large and the jib 6 attempts to lower itself to the point where the rated load is exceeded, its movement is restricted, thereby maintaining the stability of the track-traveling crane 1 during operation.

[0029] Furthermore, the ground clearance limiting mechanism 22 uses a rated load curve selected according to the rotation angle of the jib 6 detected by the rotation angle detector 13, and limits the lifting of the load by a control signal output from the control device 12 based on the lowering angle of the jib 6 detected by the lowering angle detector 14 and the load of the load detected by the load load detector 15.Even if an attempt is made to lift a load that exceeds the rated load, the movement is limited, thereby maintaining the stability of the track-traveling crane 1 during operation.

[0030] FIG. 6 is a flowchart explaining the specific control procedures executed by the control device 12 when the track-traveling crane 1 is in operation. First, at the start of operation, in step S1, the jib 6 lowering angle, rotation angle, load of the suspended load, and wheel pressure are confirmed based on the detection values ​​from various sensors, and then in step S2, the suspended load is lifted.

[0031] Then, in step S3, it is determined whether the jib 6's tilting angle, rotation angle, suspended load weight, and wheel pressure are each below the allowable values, and if any one of them exceeds the allowable value, the process proceeds to step S4, where an alarm and error message are displayed, and operation is stopped in step S5.

[0032] If the tilting angle, slewing angle, load of the suspended load, and wheel pressure are each below the allowable values ​​in step S3, the jib 6 will be tilted in step S6 or rotated in step S7 (usually, each operation is performed selectively).

[0033] For example, if the process proceeds to lowering the jib 6 in step S6, a determination is made in step S8 as to whether the lowering angle has reached its limit. Unless the lowering angle has reached its limit, the process proceeds to step S9 to check the wheel pressure. Next, in step S10, a determination is made as to whether the wheel pressure is below the allowable value (allowable wheel pressure of the foundation). As long as the wheel pressure is below the allowable value, the process from step S6 is repeated. If it is determined in previous step S8 that the lowering angle has reached its limit, or if it is determined in previous step S10 that the wheel pressure exceeds the allowable value, the process proceeds to step S11, where an alarm and error message are displayed, operation is stopped in step S12, and the raising of the jib 6 is performed in step S13.

[0034] On the other hand, if the process proceeds to the rotation operation of the jib 6 in step S7, it is determined in step S14 whether the rotation angle has reached its limit. Unless the rotation angle has reached its limit, the process proceeds to step S15 to check the wheel pressure. Then, in step S16, it is determined whether the wheel pressure is below the allowable value. As long as the wheel pressure is below the allowable value, the process from step S7 is repeated. If it is determined in the previous step S14 that the rotation angle has reached its limit, or if it is determined in the previous step S16 that the wheel pressure exceeds the allowable value, the process proceeds to step S17, an alarm and error message are displayed, operation is stopped in step S18, and the rotation operation is performed in the opposite direction to the previous one in step S19.

[0035] Therefore, according to the above embodiment, rather than determining the lowering angle of the jib 6 when the maximum wheel pressure is generated as the lowering limit, the wheel pressure is constantly measured and monitored using wheel pressure detector 11 to ensure that it does not exceed the allowable value (allowable wheel pressure of the foundation), and control is performed based on the stability of the track-traveled crane 1 within a range where the wheel pressure does not exceed the allowable value. Therefore, unlike in the past when a lowering limit was determined and only the lowering angle of the jib 6 was controlled, when the jib 6 is rotated so that it faces the diagonal direction of the rectangle connecting the legs 9 of the track-traveled crane 1, and then further rotated so that it faces in a direction parallel to the rails 2, the lowering angle of the jib 6 and the load of the suspended load can be made larger than before, and the lifting capacity of the track-traveled crane 1 during operation can be maximized.

[0036] The track-traveling crane of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0037] 1. Track-traveling crane 2 Rails 3. Running body 6 Jib 9 Legs 10 Running wheels 11 Wheel pressure detector 12 Control device 13 Turning angle detector 14. Pitch angle detector 15 Suspended load detector

Claims

1. A track-traveling crane is provided with a running body having legs with a plurality of running wheels that can roll along a rail, and the running body travels on the rail to perform loading and unloading work, A track-traveling crane equipped with a wheel pressure detector that detects the wheel pressure applied to each running wheel of the leg, and a control device that controls the jib's lowering angle and rotation angle so that they do not exceed their limits in order to ensure stability during work, and in parallel with this control, monitors the wheel pressure detected by the wheel pressure detector to ensure that it does not exceed the allowable wheel pressure of the foundation.

2. 2. The track-traveling crane according to claim 1, wherein the control device is configured to continue the lowering or swinging operation until the jib lowering angle or swing angle reaches its limit as long as the wheel pressure does not reach the allowable wheel pressure of the foundation, and to stop the lowering or swinging operation when the wheel pressure reaches the allowable wheel pressure of the foundation even if the jib lowering angle or swing angle has not reached its limit.

3. 3. A track-traveling crane according to claim 1 or 2, further comprising a rotation angle detector for detecting the rotation angle of the jib, a lowering angle detector for detecting the lowering angle of the jib, and a load load detector for detecting the load of the load lifted by the jib, and the control device is configured to perform control to ensure stability during operation based on these detected values.

4. 4. A track-traveling crane according to claim 2 or 3, wherein wheel pressure detectors are provided at pivot points of the legs relative to the traveling body, the load detected by said wheel pressure detectors is input as a detected value to the control device, and the wheel pressure is determined by dividing the detected value by the number of wheels per leg.

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