crane

Abstract

To reduce a positional deviation between a boom tip and a hook caused after starting winding operation.SOLUTION: A crane 1 includes a boom 4 and hoists a suspended load L from a tip of the boom 4 through a hook 34. The crane performs position adjustment control for bringing a position of the hook 34 and a position of the tip of the boom 4 close to each other when viewed from a vertical direction during a period from start of the hoisting operation until the suspended load L is separated from a ground contact surface. By the position adjustment control, the derricking operation is performed to move the boom 4 up or down according to a relative movement direction of the hook 34 with respect to a crane main body 3 so as to perform speed adjustment with respect to winding-up operation of the hook 34.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] Patent Document 1 proposes a method of attaching a Global Navigation Satellite System (GNSS) receiver to the boom tip and the hook, and adjusting the position of the boom tip before starting lifting so that the position of the boom tip viewed from above matches the position of the hook viewed from above. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-169087 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a crane starts hoisting a load, if the hook is not positioned directly above the center of gravity of the load, the load's posture may change from the start of hoisting, causing a misalignment between the tip of the boom and the hook. However, the above-mentioned conventional cranes were unable to deal with a positional misalignment between the boom tip and the hook that occurred after hoisting of the load began.

[0005] The present invention aims to effectively deal with misalignment between the boom tip and the hook that occurs after starting to hoist a load. [Means for solving the problem]

[0006] The present invention relates to a crane that hoists a load from a boom and a hook at the end of the boom, and performs position adjustment control to bring the position of the hook closer to the position of the end of the boom when viewed in the vertical direction during the period from the start of the hoisting operation until the load leaves the ground. stomach, The position adjustment control is performed according to a relative movement direction of the hook with respect to the crane body from the start of the hoisting operation to the time when the load leaves the ground surface, In the position adjustment control, the speed of the boom hoisting operation is adjusted depending on the relative movement direction of the hook with respect to the crane body, and the speed of the hook hoisting operation is adjusted depending on the relative movement direction of the hook with respect to the crane body. , The structure is as follows. Effect of the Invention

[0007] According to the present invention, it is possible to effectively deal with the positional misalignment between the tip of the boom and the hook that occurs after starting to hoist a load. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side view of a crane according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic plan view of an upper rotating body of the crane. [Diagram 3] FIG. 2 is a block diagram showing the configuration of a crane control device and its surroundings. [Figure 4] 13 is a flowchart of a position adjustment control. [Diagram 5] FIG. 11 is an explanatory diagram showing a state in which there is no change in the relative position of the hook with respect to the boom in a plan view during the hoisting operation of a suspended load. [Figure 6] FIG. 11 is an explanatory diagram showing a state in which a relative position change occurs in the hook toward the upper rotating body side with respect to the boom in a plan view. [Figure 7] 1 is an explanatory diagram showing a state in which a relative position change occurs in a plan view of the hook with respect to the boom toward the opposite side to the upper rotating body (the side opposite the crane body). FIG. [Figure 8] FIG. 1 is a side view of a crane illustrating a cause of relative positional deviation of the hook position with respect to the boom tip position in a plan view. [Figure 9] 13 is a display example showing operation instructions for an operator on a crane status display screen displayed on a display device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Crane outline] Fig. 1 is a side view of crane 1, and Fig. 2 is a schematic plan view of the upper rotating body 3 of crane 1. Crane 1 is a so-called mobile crawler crane. In describing crane 1, as shown in Fig. 2, the front-rear and left-right directions as seen by an operator on the upper rotating body 3 as the crane body will be described as the front-rear and left-right directions of crane 1. Unless otherwise specified, the directions of each part will be described assuming that the lower running body 2 is in a state in which the front-rear direction is aligned with that of the upper rotating body 3 (standard posture), as a general rule. In addition, in the following explanation, it is assumed that the crane 1 is located on a horizontal plane, and when referring to a "plan view," it refers to a state viewed from a direction perpendicular to the horizontal plane on which the crane 1 is located, i.e., from the vertical direction.

[0010] As shown in FIG. 1, the crane 1 is composed of a self-propelled crawler-type lower running body 2, an upper rotating body 3 rotatably mounted on the lower running body 2, and a boom 4 attached to the front side of the upper rotating body 3 so that it can be raised and lowered.

[0011] The lower traveling body 2 includes a main body 21 and crawlers 22 provided on both the left and right sides of the main body 21. The left and right crawlers 22 are each rotationally driven by a traveling hydraulic motor (not shown).

[0012] A boom 4 is attached so as to be capable of being raised and lowered on the front side of the upper rotating body 3. A sheave 43 that guides the hoisting rope 32 is rotatably attached to the upper end of the boom 4. Further, a lower end portion of a mast 31 is supported on the upper rotating body 3 rearward of the boom 4. The upper rotating body 3 is driven to rotate about an axis in the vertical direction relative to the lower traveling body 2 by a hydraulic motor for rotation (not shown).

[0013] A counterweight 5 for balancing the weight of the boom 4 and the suspended load L is attached to the rear of the upper rotating body 3. The number of counterweights 5 can be increased or decreased as required.

[0014] A hoisting winch 42 for raising and lowering the boom 4 is disposed near the counterweight 5, and in front of it is a hoisting winch 36 for winding in and unwinding the hoisting rope 32. The hoisting winch 36 uses a hoisting hydraulic motor (not shown) to wind in and unwind the hoisting rope 32, and hoist up and lower the hook 34 and the suspended load. In addition, a cab 33 is disposed on the right front side of the upper rotating body 3.

[0015] The mast 31 is equipped with an upper spreader 35 at its upper end, and the upper spreader 35 is connected to one end of a pendant rope 44 whose other end is connected to the upper end of the boom 4. A lower spreader (not shown) is provided below the upper spreader 35, and when a hoisting rope 37 is wound multiple times between them and reeled in or out by a hoisting winch 42, the distance between the upper spreader 35 and the lower spreader changes, causing the boom 4 to be hoisted. The boom hoisting winch 42 is driven by a hoisting hydraulic motor (not shown).

[0016] [Crane control system] A crane control device 60 is provided in the cab 33 of the upper rotating body 3. FIG. 3 is a block diagram showing the configuration of the control device 60 and its surroundings. The control device 60 controls the crane 1. This is an on-board control terminal that mainly controls various operations of the crane 1, such as running, rotating, and hoisting and lowering the load. The control device 60 includes a controller 61 including an arithmetic processing device having a CPU, memory devices such as ROM and RAM, and other peripheral circuits. The controller 61 includes a software module of a position adjustment control unit 611 that performs control of the position adjustment of the tip of the boom 4 and the hook 34, which will be described later. The position adjustment control unit 611 may be configured from hardware.

[0017] An input unit 621 , a display device 622 , an alarm device 623 , an operating lever 624 , and a memory 625 are connected to the controller 61 , which together constitute the control device 60 . Furthermore, to the controller 61, a load cell 631, a boom angle sensor 632, a rotation amount sensor 633, a control valve 635, and positioning units 641 to 643 are connected.

[0018] The input unit 621 is, for example, an input interface such as a touch panel, and outputs a control signal corresponding to an operation by an operator to the controller 61. The operator can operate the input unit 621 to input the length of the boom 4, the weight of the suspended load, and various other settings and various inputs required for operation. The display device 622 includes, for example, a touch panel display that is also used as the input unit 621, and displays information such as the weight of the load, the boom angle, and the rotation angle of the upper rotating body 3 on the display screen based on a control signal output from the controller 61 (see FIG. 9). The alarm device 623 generates an alarm based on a control signal output from the controller 61 .

[0019] The operation lever 624 is used to manually input operations for causing the crane 1 to perform various operations, and a control signal corresponding to the amount of operation of the operation lever 624 is input to the controller 61. For example, the operation lever 624 can perform operation inputs for the traveling operation of the lower traveling body 2, the rotating operation of the upper rotating body 3, the raising and lowering operation of the boom 4, and the lifting and lowering operation of the suspended load.

[0020] The load cell 631 is attached to the upper spreader 35 and detects the tension acting on the pendant rope 44 that raises and lowers the boom 4, and outputs a control signal corresponding to the detected tension to the controller 61.

[0021] The boom angle sensor 632 is attached to the base end side of the boom 4, detects the hoisting angle of the boom 4 (hereinafter also referred to as the boom angle), and outputs a control signal corresponding to the detected boom angle to the controller 61. The boom angle sensor 632 detects, for example, a ground angle, which is an angle with respect to the horizontal plane, as the boom angle.

[0022] The turning amount sensor 633 is attached between the lower traveling body 2 and the upper rotating body 3, detects the turning angle of the upper rotating body 3, and outputs a control signal corresponding to the detected turning angle to the controller 61. The turning amount sensor 633 detects, for example, an angle around a vertical axis as the turning angle.

[0023] The control valve 635 is composed of a plurality of valves that can be switched in response to a control signal from the controller 61 . For example, the control valve 635 includes a valve that controls the rotational drive of the left and right crawlers 22 of the lower traveling body 2, a valve that controls the rotational operation of the upper rotating body 3, a valve that controls the rotational drive of the hoisting winch, a valve that controls the rotational drive of the hoisting winch, and the like.

[0024] The positioning units 641, 642, and 643 are provided in the cab 33 of the upper rotating body 3, near the tip of the boom 4, and on the hook 34, respectively. These are GNSs that detect the respective positions. The positioning unit 641 is not limited to being provided in the cab 33, and may be provided at any position on the upper rotating body 3. Each of the positioning units 641 to 643 measures the current position (latitude, longitude, altitude) of the respective mounting positions, and periodically outputs to the controller 61 the positioning data indicating the current position, etc.

[0025] In the following description, the "tip of the boom 4" refers to the position where the hoisting rope 32 that hangs down from the boom 4 toward the hook 34 starts hanging down (reference symbol C in FIG. 2). The positioning unit 642 attached near the tip of the boom 4 and the "tip of the boom 4" are somewhat separated in a plan view (position projected onto a horizontal plane), and their respective positions do not strictly coincide. On the other hand, the relative positional relationship between the positions of the positioning units 641, 642 and the "tip of the boom 4" is known. Therefore, the controller 61 calculates the position of the "tip of the boom 4" in a planar view from the positions of the positioning units 641, 642 in a planar view and the hoisting angle of the boom 4, as necessary. In the following description, the position of the "tip of the boom 4" in a planar view will be referred to simply as the "boom tip position," and the position of the "hook 34" in a planar view will be referred to simply as the "hook position." The "hook position" may be the attachment position of the positioning unit 643 on the hook 34, or may be the center of gravity position of the hook 34. When the hook position and the attachment position of the positioning unit 643 do not coincide with each other, it is preferable that the control device 60 holds the relative positional relationship as setting data.

[0026] [Position adjustment control] The position adjustment control by the position adjustment control unit 611 will be described in detail with reference to FIGS. Fig. 4 is a flowchart of the position adjustment control, Fig. 5 is an explanatory diagram showing a state in which there is no relative position change in the hook 34 with respect to the boom 4 in a plan view during the hoisting operation of the load L, Fig. 6 is an explanatory diagram showing a state in which there is a relative position change in the hook 34 with respect to the boom 4 toward the upper rotating body 3 side (the crane body side) in a plan view, and Fig. 7 is an explanatory diagram showing a state in which there is a relative position change in the hook 34 with respect to the boom 4 toward the opposite side from the upper rotating body 3 (the opposite side to the crane body) in a plan view. Note that the load L is not shown in Figs. 5 to 7. The position adjustment control is an operation control for reducing the relative positional fluctuation that occurs in the planar position of the hook 34 with respect to the boom 4 between the start of the hoisting operation of the load L and at least the time when the load L leaves the ground surface.

[0027] As shown in FIG. 4, when hoisting the load L, the hook 34 and the load L are connected, and when, for example, a command to execute the hoisting operation is input from the input unit 621 (step S1), the hoisting winch 36 is driven to start hoisting (step S3). Before starting to drive the hoisting winch 36, the operator may use the operating lever 624 to adjust the position of the boom 4 in advance so that the tip of the boom 4 is directly above the hook 34 connected to the load L.

[0028] When the hoisting operation is started, the position adjustment control unit 611 acquires the position coordinates of the cab 33, the tip of the boom 4, and the hook 34 of the upper rotating body 3 from the positioning data of the positioning units 641 to 643 (step S5). The position adjustment control unit 611 develops a crane coordinate system on the horizontal plane of the upper rotating body 3 of the crane 1, and calculates the position coordinates of each of the positioning units 641 to 643 projected onto the crane coordinate system. Here, the crane coordinate system is, as shown in FIG. 2, a coordinate system developed on a horizontal plane consisting of a front-rear axis parallel to the longitudinal direction of the boom 4 in a plan view and a left-right axis perpendicular to the front-rear axis. It is a rectangular coordinate system.

[0029] The position adjustment control unit 611 calculates the boom tip position and the hook position in the crane coordinate system from the position coordinates of each of the positioning units 641 to 643. Then, it calculates the amount of deviation between the boom tip position and the hook position (step S7).

[0030] Furthermore, the position adjustment control unit 611 determines whether there is a deviation between the boom tip position and the hook position based on the above calculation (step S9). In this case, it is preferable to set a threshold value in advance for the amount of deviation between the boom tip position and the hook position. In accordance with this, if the calculated amount of deviation is less than the threshold value, the position adjustment control unit 611 determines that the boom tip position and the hook position match, and if the calculated amount of deviation is equal to or greater than the threshold value, determines that there is a deviation between the boom tip position and the hook position.

[0031] Then, when it is determined that a deviation occurs between the boom tip position and the hook position (step S9: YES), the position adjustment control unit 611 performs at least one of the vertical movement of the boom 4 and the rotation operation of the upper rotating body so that the boom tip position and the hook position approach each other (step S11). At that time, the hoisting speed may also be adjusted. Then, the process proceeds to step S13.

[0032] Moreover, if it is determined that no deviation has occurred between the boom tip position and the hook position (step S9: NO), the position adjustment control unit 611 skips step S11 and advances the process to step S13.

[0033] Then, in step S13, the position adjustment control unit 611 determines whether or not the load L is in a ground-off state. Ground-off refers to a state in which all portions of the load L are separated from the contact surface (ground) by hoisting. The position adjustment control unit 611 may determine that the line has run off the ground based on the passage of a specified time from the start of winding, or based on the arrival of a specified winding amount from the start of winding.

[0034] Then, if it is determined that the load L is not off the ground, the position adjustment control unit 611 returns to step S5, again acquires the current position coordinates of the cab 33 of the upper rotating body 3, the tip of the boom 4, and the hook 34, and repeats the subsequent steps S5 to S13. Moreover, when it is determined that the load L is in a ground-lifted state, the position adjustment control unit 611 ends the position adjustment control. It is not necessary to end the position adjustment control strictly when the vehicle has run off the ground, but it is sufficient to end the position adjustment control at least after the vehicle has run off the ground. Furthermore, in step S13, the position adjustment control ends, but the hoisting operation of the load L continues.

[0035] We will now explain in more detail the various modes of deviation between the boom tip position and the hook position in step S9 of the above-mentioned position adjustment control, and the operational control of the up and down movement of the boom 4, the rotation operation of the upper rotating body 3, and the adjustment of the hoisting speed that is executed for each mode.

[0036] As shown in Figure 5, in a state where the hook 34 is located directly below the tip of the boom 4, that is, in an ideal state where the boom tip position and the hook position are aligned, the position adjustment control unit 611 performs the hoisting operation of the load L by maintaining a preset specified hoisting speed Pu without changing the hoisting angle of the boom 4 and the rotation angle of the upper rotating body 3.

[0037] On the other hand, there are cases where the hook position is shifted relatively backward with respect to the boom tip position in a plan view (Figure 6), where the hook position is shifted relatively forward with respect to the boom tip position in a plan view (Figure 7), and where the hook position is shifted relatively to the left or right with respect to the boom tip position in a plan view (hook 34 shown by the two-dot chain line in Figure 2).

[0038] One of the causes is the forward tilt of the upper rotating body 3 of the crane 1 and the deflection of the boom 4 caused by the weight of the suspended load L, as shown by the arrow a in Figure 8. In this case, the hook position shifts backward relative to the boom tip position in a plan view.

[0039] Another cause is that, as shown by the arrow b in Fig. 8, the relative position of the hook 34 in a plan view is misaligned with respect to the center of gravity g of the load L at the start of the hoisting operation. In that case, the load L tilts due to hoisting, and the hook 34 also moves as if pulled by the load L, causing a misalignment. In the case of this cause, the direction of the misalignment after hoisting starts is determined by the direction of the initial misalignment of the hook position with respect to the center of gravity g of the load L, so misalignment can occur in any direction on the horizontal plane.

[0040] 6, when the hook position is shifted backward relative to the boom tip position in a plan view, the position adjustment control unit 611 drives the hoisting winch 42 to perform a hoisting operation on the boom 4 in the direction of the arrow Bu. This moves the boom tip position backward, reducing or eliminating the amount of deviation from the hook position. In this case, since the hook 34 is pulled upward by the raising and lowering of the boom 4, the position adjustment control unit 611 controls the operation of the hoisting winch 36 so that the hoisting speed is decelerated at an adjustment speed Ad in the counter-hoisting direction relative to the specified hoisting speed Pu so that the hoisting operation of the load L is not suddenly accelerated.

[0041] The magnitude of the adjustment speed Ad may be determined according to the amount of deviation between the boom tip position and the hook position that occurs relatively in the fore-and-aft direction in a plan view. For example, table data showing the correspondence between the deviation amount between the boom tip position and the hook position and the adjustment speed Ad may be prepared, and the adjustment speed Ad may be determined by referring to the table data. In addition, the correlation between the deviation amount between the boom tip position and the hook position and the adjustment speed Ad may be expressed as a formula, and the adjustment speed Ad may be calculated from the deviation amount. In these cases, the absolute value of the adjusted speed Ad in the anti-winding direction may be greater than the specified winding speed Pu, in which case the hoisting winch 36 is driven in the winding down direction instead of the winding up direction.

[0042] 7, when the hook position is misaligned forward relative to the boom tip position in a plan view, the position adjustment control unit 611 drives the hoisting winch 42 to hoist and lower the boom 4 in the direction of arrow Bd. This moves the boom tip position forward, reducing or eliminating the misalignment with the hook position. In this case, since the hook 34 is lowered downward by the raising and lowering of the boom 4, the position adjustment control unit 611 controls the operation of the hoisting winch 36 so that the hoisting speed of the load L is accelerated and adjusted at an adjustment speed Au in the hoisting direction relative to the specified hoisting speed Pu so as not to cause a decrease in the hoisting speed of the load L or to prevent the load L from colliding with the ground.

[0043] The adjustment speed Au may also be determined in accordance with the amount of deviation between the boom tip position and the hook position that occurs relatively in the fore-and-aft direction in a plan view. In this case, the adjustment speed Au may be determined using table data showing the correspondence between the deviation amount between the boom tip position and the hook position and the adjustment speed Au, or the correlation between the deviation amount between the boom tip position and the hook position and the adjustment speed Au may be expressed as a formula to calculate the adjustment speed Ad. .

[0044] 2, when the hook position is displaced left or right relative to the boom tip position in a plan view, the position adjustment control unit 611 drives the hydraulic motor for rotation to rotate the upper rotating body 3 and the boom 4 to the right or left. In this case, the amount of rotation is preferably set equal to an amount that cancels the amount of left or right deviation. This reduces or eliminates the amount of deviation between the boom tip position and the hook position.

[0045] Furthermore, the relative deviation of the hook position with respect to the boom tip position in a plan view may occur simultaneously in both the front-rear direction and the left-right direction. In that case, the position adjustment in the front-rear direction shown in FIG. 6 or FIG. 7 and the position adjustment in the left-right direction shown in FIG. 2 may be performed in parallel.

[0046] [Technical Effects of the Invention Embodiments] As described above, the controller 61 of the control device 60 of the crane 1 is equipped with a position adjustment control unit 611 that performs position adjustment control to bring the hook position and the boom tip position closer together when viewed vertically from the start of the hoisting operation until the load L leaves the ground surface. This makes it possible to effectively reduce the positional deviation between the boom tip position and the hook position that occurs after the crane 1 starts hoisting the load L. This also makes it possible to effectively suppress the occurrence of swaying of the load L after it is lifted off the ground.

[0047] In addition, the position adjustment control unit 611 detects the movement direction of the hook 34 relative to the upper rotating body 3 and performs position adjustment control, making it possible to more appropriately reduce the positional deviation between the boom tip position and the hook position.

[0048] In addition, in the position adjustment control, the position adjustment control unit 611 either raises or lowers the hoisting operation of the boom 4 and adjusts the speed of the hoisting operation of the hook 34 depending on the moving direction of the hook 34 relative to the crane body. Therefore, the raising and lowering operation of the boom 4 can effectively reduce the positional misalignment between the boom tip position and the hook position after winding begins, and it is also possible to suppress changes in the winding speed caused by the raising and lowering operation of the boom 4.

[0049] In particular, in the position adjustment control, when the hook 34 moves relatively toward the upper rotating body 3 (rearward), the position adjustment control unit 611 performs speed adjustment to slow down the hoisting speed (including the case where the hoisting speed is set to 0) or switch to lowering for the hoisting operation of the hook 34 together with the hoisting operation of the boom 4. This effectively reduces the positional deviation between the boom tip position and the hook position after hoisting starts due to the hoisting operation of the boom 4. Also, sudden hoisting of the load L due to the hoisting operation of the boom 4 is avoided, making it possible to perform the hoisting operation stably.

[0050] Furthermore, in the position adjustment control, when the hook 34 moves relatively toward the opposite side of the upper rotating body (forward), the position adjustment control unit 611 performs speed adjustment to increase the hoisting speed for the hoisting operation of the hook 34, along with the hoisting and lowering operation of the boom 4. This effectively reduces the positional deviation between the boom tip position and the hook position after hoisting begins due to the hoisting operation of the boom 4. Also, a sudden slowdown of the load L due to the hoisting and lowering operation of the boom 4 is avoided, making it possible to perform the hoisting operation stably.

[0051] In addition, in the position adjustment control, when the hook 34 moves to the left or right relative to the boom 4, the position adjustment control unit 611 performs a rotation operation of the upper rotating body 3 in the direction of the movement. Therefore, the left / right direction between the boom tip position and the hook position after the start of hoisting is It is also possible to effectively reduce positional deviation in the direction. Furthermore, by performing the rotation operation of the upper rotating body 3 in parallel with the raising and lowering of the boom 4 described above, it is possible to accommodate relative positional deviations in all directions between the boom tip position and the hook position after winding begins.

[0052] [others] The details shown in the above embodiment of the invention can be modified as appropriate without departing from the spirit of the invention. For example, in the above-mentioned position adjustment control, an example was given of a case in which the raising and lowering of the boom 4 after the start of hoisting the load L, the rotation of the upper rotating body 3, and the hoisting and lowering of the hook 34 are performed by the operation control of the position adjustment control unit 611, without being operated by an operator. Alternatively, each of the above operations may be performed by an operator. In this case, it is preferable that the position adjustment control unit 611 issues operational instructions to the operator via, for example, the display device 622 or the like.

[0053] FIG. 9 shows an example of a display screen G of the status display of the crane 1 displayed on the display device 622. For example, if a horizontal positional deviation occurs between the boom tip position and the hook position during the time from the start of the hoisting operation until the load L leaves the ground, the position adjustment control unit 611 displays instruction messages m1 and m2 for issuing operational instructions to the worker on the status display screen G. The example of Fig. 9 illustrates a case in which, as in Fig. 6 described above, an instruction message m1 instructing the user to raise the boom 4 and an instruction message m2 instructing the user to adjust the speed in the counter-hoisting direction relative to the specified hoisting speed are displayed when the hook position is displaced rearward relative to the boom tip position. In addition to the above examples, if the hook position is shifted forward relative to the boom tip position, as in Figure 7, or if the hook position is shifted to the left or right relative to the boom tip position, as in Figure 2, an instruction message is displayed instructing the user to perform the corresponding operation.

[0054] Further, the operational instructions given to the worker are not limited to the display device 622, but any means perceptible by the worker may be used, such as the lighting of a lamp indicating the content of the instruction, or a voice message from a voice output means. In addition, the controller 61 instructs the raising and lowering of the boom 4, but the winding speed may be adjusted appropriately by the control of the controller 61.

[0055] Furthermore, the position adjustment control of the above embodiment can be applied to any type of crane that hoists a load, including overhead cranes, jib cranes, truck cranes, crab cranes, wheel cranes, etc. In other words, it can also be applied to cranes that have a beam supporting a hook as a boom that does not hoist. Furthermore, the position adjustment control for bringing the position of the hook closer to the position of the tip of the boom is not limited to the rotation of the boom, and the position adjustment control may be performed by the extension and contraction of the boom like a telescopic crane. [Explanation of symbols]

[0056] 1. Crane 2 Undercarriage 3. Upper rotating body 4. Boom 5 Counterweight 32 Winding rope 33 Cab 34 Hook 36 Lifting winch 37 Descending Rope 42 Boom hoisting winch 44 Pendant Rope 60 Control device 61 Controller 611 Position adjustment control section 621 Input section 622 Display device 624 Operating lever 632 Boom angle sensor 633 Turning amount sensor 635 Control Valve 641~643 Positioning unit m1,m2 instruction message

Claims

1. A crane that hoists a load from a boom and a hook at the tip of the boom, performing a position adjustment control for bringing the position of the hook and the position of the tip of the boom closer together when viewed in the vertical direction during a period from the start of a hoisting operation until the load leaves the ground; The position adjustment control is performed according to a relative movement direction of the hook with respect to the crane body from the start of the hoisting operation to the time when the load leaves the ground surface, In the position adjustment control, the speed of the boom hoisting operation is adjusted depending on the relative movement direction of the hook with respect to the crane body, and the speed of the hook hoisting operation is adjusted depending on the relative movement direction of the hook with respect to the crane body. crane.

2. In the position adjustment control, when the hook moves relatively to the crane body side, the boom is raised and lowered, and the hoisting speed of the hook is reduced or switched to lowering. The crane of claim 1.

3. In the position adjustment control, when the hook moves relatively to the opposite side to the crane body, the boom is lowered and the hoisting speed of the hook is increased. A crane as claimed in claim 1 or 2.

4. In the position adjustment control, when the hook moves to the left or right relative to the boom, the crane body is rotated in the direction of the movement. A crane as claimed in any one of claims 1 to 3.

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