JP2017043430A - Weight floating amount adjustment device of moving crane and weight floating amount adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weight floating amount adjustment device of a moving crane which can easily obtain a state that a separation-type weight is floated from the ground surface by a prescribed dimension when hoisting a cargo.SOLUTION: A weight floating amount adjustment device 60 comprises: a detection part 61 which detects a rotation amount of a mast undulation winch; a storage part 65 which stores the rotation amount of the mast undulation winch in a state that a separation-type weight is floated from the ground surface by a prescribed dimension as a reference rotation amount in advance; a calculation part 66 which calculates a difference between the rotation amount which is detected by the detection part 61 and the reference rotation amount when the moving crane is assembled in a work site; and a notification part (display part) 64 which rotates the mast undulation winch with respect to an operator by an amount of the difference which is calculated by the calculation part 66, and promotes the setting of the rotation amount to the reference rotation amount.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a weight lifting amount adjusting device and a weight lifting amount adjusting method for a mobile crane including a separation-type weight disposed behind an upper swing body.

  Conventionally, as a large crane, a so-called counterbalance crane as described in, for example, Patent Document 1 is known. This type of crane has an upper swing body that is pivotably mounted on a lower traveling body, a boom that has a proximal end supported by the front of the upper swing body, and a suspension that is suspended from the tip of the boom. And a mast whose base end is supported by the upper swing body so as to be raised and lowered at a position rearward of the base end of the boom and whose tip is connected to the tip of the boom via a boom guy line and a boom hoisting rope. And a separation-type weight suspended from the mast and disposed behind the upper revolving structure, and configured to lift the separation-type weight from the ground by a predetermined dimension when the load is lifted by the suspension tool. ing.

JP 2008-287112 A

  By the way, as the separation-type weight, there are a pallet weight having a weight mounted on a pallet, or a counterweight carriage having wheels. However, when a load is lifted by a lifting tool, the separation-type weight itself has a predetermined dimension from the ground. It is necessary to be in an appropriate state in which the separation type weight does not hinder the turning of the upper turning body.

  However, mobile cranes, especially large mobile cranes, are disassembled, transported, and assembled at the site where work is performed, so it is not possible to grasp whether the separate weights are in an appropriate state at the end of assembly. Can not. The actual situation is that the operator adjusts the floating amount while actually lifting the luggage, and it is difficult to make adjustments in different locations each time.

  The present invention has been made in view of the above points, and the problem is that when the assembly is completed at the work site, the amount of rotation of the mast hoisting winch is appropriately set so that the separation weight can be used when lifting the load. It is an object of the present invention to provide a weight lifting amount adjusting device and a weight lifting amount adjusting method for a mobile crane that can easily realize a state of lifting a predetermined dimension from the ground.

  In order to solve the above-described problems, the present invention provides a mobile crane that includes an upper swing body that is pivotably mounted on a lower traveling body, and a base end that is supported by the front portion of the upper swing body so as to be raised and lowered. A boom, a suspension suspended from the tip of the boom, a base end supported by the upper revolving unit at a position rearward of the base end of the boom, and a tip extending from a boom guy line and a boom hoisting rope. A mast connected to the tip of the boom via a mast, a mast hoisting winch for raising and lowering the mast, and a separation-type weight hung from the mast and arranged behind the upper swing body, It is assumed that the separated weight is configured to be lifted from the ground when the load is lifted. As a weight lifting amount adjusting device for a mobile crane, a detection unit that detects the amount of rotation of the mast hoisting winch and a rotation amount of the mast hoisting winch in a state where the separation type weight is lifted from the ground by a predetermined dimension in advance A storage unit that stores the amount, a calculation unit that calculates a difference between the rotation amount detected by the detection unit and the reference rotation amount when the mobile crane is assembled at a work site, and a calculation performed by the calculation unit And a notifying unit that urges the operator to rotate the mast hoisting winch by the amount corresponding to the difference and to set it to the reference rotation amount.

  In this configuration, when the mobile crane is assembled at the work site, the difference between the rotation amount of the mast hoisting winch detected by the detection unit and the reference rotation amount stored in the storage unit is calculated by the calculation unit. The notification unit prompts the operator to rotate the mast undulation winch by the amount and set it to the reference rotation amount. When the operator rotates the mast hoisting winch based on the prompt of the notification unit and sets the rotation amount to the reference rotation amount, the rotation amount of the mast hoisting winch is appropriately set when the assembly at the work site is finished. Can do. Thereafter, when the load is lifted by the lifting tool, it is possible to easily realize a state in which the separation type weight is lifted from the ground by a predetermined dimension.

  Here, the separation-type weight and the rear part of the upper swing body may be connected by a connection beam so that the length can be changed. In this case, the reference rotation amount of the mast hoisting winch in a state where the separation type weight is lifted from the ground by a predetermined dimension varies depending on the length of the coupled beam.

  Corresponding to this, it further comprises a measuring unit for measuring the length of the coupled beam, and the reference rotation amount is set for each length of the coupled beam, stored in the storage unit, and calculated. The unit is preferably provided so as to calculate a difference between a reference rotation amount corresponding to the length of the coupled beam measured by the measurement unit and a rotation amount detected by the detection unit. In this case, corresponding to the fact that the reference rotation amount of the mast undulation winch differs for each length of the coupled beam, the length of the coupled beam is measured by the measurement unit, and the length of the coupled beam measured by this measurement unit is measured. The calculation unit calculates the difference between the reference rotation amount corresponding to and the rotation amount of the mast undulation winch detected by the detection unit, and rotates the mast undulation winch for the operator and sets it to the reference rotation amount. Is prompted by the notification unit. As a result, it is possible to easily realize a state in which the separation type weight is lifted from the ground by a predetermined dimension corresponding to the length of the connection beam.

  Here, an example of the separation-type weight is a counterweight carriage having wheels.

  The weight lift adjustment method of the present invention is similar to the weight lift adjustment device of the present invention. The upper swing body that is turnably mounted on the lower traveling body and the base end of the upper swing body are raised and lowered. A boom supported by the boom, a hanger suspended from the tip of the boom, a base end supported by the upper swinging body at a position rearward of the base end of the boom, and a tip of the boom guy line and A mast connected to the tip of the boom via a boom hoisting rope, a mast hoisting winch for hoisting the mast, and a separate weight suspended from the mast and disposed behind the upper swing body Suppose a mobile crane configured such that the separated weight is lifted off the ground when a load is lifted by the lifting tool. The mobile crane stores a rotation amount of the mast hoisting winch and a rotation amount of the mast hoisting winch in a state in which the separation type weight is lifted from the ground in advance as a reference rotation amount. And a storage unit. And when the said mobile crane is assembled in a work site, the rotation amount detected by the said detection part is set to the said reference rotation amount.

  With this configuration, the amount of rotation of the mast hoisting winch can be appropriately set when the assembly at the work site is completed. Thereafter, when the load is lifted by the lifting tool, it is possible to easily realize a state in which the separation type weight is lifted from the ground by a predetermined dimension.

  According to the weight lifting amount adjusting device and weight lifting amount adjusting method of the mobile crane according to the present invention, the amount of rotation of the mast hoisting winch can be appropriately set at the time of assembly at the work site, and Sometimes, it is possible to easily realize a state in which the separation type weight is lifted from the ground by a predetermined dimension.

FIG. 1 is a side view showing the overall configuration of a crawler crane according to an embodiment of the present invention. FIG. 2 is a block diagram of a weight lifting amount adjusting device installed in the crawler crane. FIG. 3 is a view corresponding to FIG. 1 showing one process for explaining the assembly procedure at the work site. FIG. 4 is a view corresponding to FIG. 1 showing the next step from the step shown in FIG. FIG. 5 is a view corresponding to FIG. 1 showing the next step from the step shown in FIG. 6 is a view corresponding to FIG. 1 showing a state in which a load is lifted from the process shown in FIG.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments that are modes for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows an overall configuration of a crawler crane 1 as a mobile crane according to an embodiment of the present invention. The crawler crane 1 includes a crane main body 10, a counterweight carriage 40 as a separate weight disposed behind the crane main body 10, and an extendable beam 50 as a connecting beam for connecting them.

  The crane body 10 includes a lower traveling body 12 traveling by a crawler 11, an upper revolving body 14 that is turnably mounted on the lower traveling body 12 with a swivel device 13 interposed therebetween, and a front portion of the upper revolving body 14. A cab 15 provided, a boom 16 supported at a front portion of the upper swing body 14 and on a side of the cab 15 so that the base end can be raised and lowered (that is, rotatable around a horizontal axis), and a base end of the boom 16 A mast 17 whose base end is supported by the upper swing body 14 so as to be raised and lowered at a position rearward of the (boom foot), and a gantry 18 and a counterweight 19 provided at the rear portion of the upper swing body 14 are provided.

  A lifting tool 22 is suspended from the tip of the boom 16 via a hoisting rope 21. One end of the hoisting rope 21 is wound around a winding winch 23 provided on the upper swing body 14 through the back side of the boom 16. Then, the hoisting tool 22 is wound or unwound by winding or unwinding the hoisting rope 21 by the winding winch 23.

  One end of a boom guy line 24 is connected to the tip of the boom 16, and a spreader 25 is provided at the other end of the boom guy line 24. A boom hoisting rope 27 is wound between the spreader 25 and a spreader 26 provided at the tip of the mast 17, and one end of the boom hoisting rope 27 passes from the spreader 26 through the back side of the mast 17. The boom hoist winch 28 provided at the base end portion 17 is wound around. Therefore, the tip of the boom 16 and the tip of the mast 17 are connected via the boom guy line 24 and the boom hoisting rope 27, and the boom hoisting winch 28 winds or unwinds the boom hoisting rope 27 so that the boom 16 is designed to move up and down.

  One end of a mast guy line 31 is connected to the tip of the mast 17, and a spreader 32 is provided at the other end of the mast guy line 31. A mast hoisting rope 34 is wound between the spreader 32 and a spreader 33 provided at the top of the gantry 18, and one end of the mast hoisting rope 34 is provided at the base end of the gantry 18. It is wound on a winch 35. The mast 17 is undulated by winding or unwinding the mast undulating rope 34 with the mast undulating winch 35.

  The counterweight carriage 40 is a separate type weight that is suspended from the tip of the mast 17 via the hanger line 36 and arranged behind the upper swing body 14, and has a plurality of wheels (only one wheel is shown in the figure). 41. These wheels 41 are rotationally driven by a hydraulic drive motor (not shown), and are provided so as to be able to turn around a vertical axis. However, during normal work, as shown in FIG. 6, when the load W is lifted by the lifting tool 22 of the crane body 10, the counterweight carriage 40 is lifted from the ground by a predetermined dimension S. It is turning.

  As shown in FIG. 6, the telescopic beam 50 can be expanded and contracted by arranging two cylindrical members 51 and 52 in a nested manner. One end (front end) of the inner cylindrical member 51 is coupled to the rear end portion of the upper swing body 14 of the crane body 10 by a coupling pin or the like, and one end portion (rear end portion) of the outer cylindrical member 52 is The counterweight carriage 40 is fixed in a penetrating manner. The other end side (rear end side) of the inner cylindrical member 51 is inserted into the inside from the other end (front end) of the outer cylindrical member 52, and the inner cylindrical member with respect to the outer cylindrical member 52 is inserted therein. The length of the telescopic beam 50 is determined in inverse proportion to the insertion length 51.

  The length of the telescopic beam 50 is changed by the relative movement of the crane body 10 and the counterweight carriage 40 in the front-rear direction or the expansion and contraction of a hydraulic cylinder disposed inside the telescopic beam 50. It has become. Although the length of the telescopic beam 50 is not shown, it is changed to a plurality of stages (for example, four stages) by a positioning device having positioning pins. 1 and 3 show a state where the length of the telescopic beam 50 is a minimum length, and FIGS. 4 to 6 show a state where the length of the telescopic beam 50 is a maximum length.

  The crawler crane 1 further includes a weight lifting amount adjusting device 60 as shown in FIG. 2, and can adjust the lifting amount of the counterweight carriage 40 when the load W is lifted. The weight floating amount adjusting device 60 receives a detection unit 61 that detects the rotation amount of the mast hoisting winch 35, a measurement unit 62 that measures the length of the telescopic beam 50, and signals from the detection unit 61 and the measurement unit 62. Controller 63 and a display unit 64 as a notification unit.

  The detection unit 61 includes an encoder attached to the rotating shaft of the mast hoisting winch 35 and the like. The amount of rotation of the mast hoisting winch 35 is the same as the amount of winding of the mast hoisting rope 34 by the mast hoisting winch 35.

  The measuring unit 62 measures the length of the telescopic beam 50 from the telescopic operation of the hydraulic cylinder when the length of the telescopic beam 50 is changed by the hydraulic cylinder, or changes the length of the telescopic beam 50 to a plurality of stages. The length of the telescopic beam 50 is measured from the operating position.

  The controller 63 and the display unit 64 are both disposed in the cab 15. The controller 63 includes a storage unit 65 composed of a DRAM or the like that stores in advance the rotation amount of the mast hoisting winch 35 when the counterweight carriage 40 is lifted from the ground as a reference rotation amount, and the crawler crane 1 is assembled at the work site. A calculation unit 66 including a comparator for calculating the difference between the rotation amount detected by the detection unit 61 and the reference rotation amount stored in the storage unit 65. Here, since the rotation amount of the mast hoisting winch 35 in a state where the counterweight carriage 40 is lifted from the ground varies depending on the length of the telescopic beam 50, the reference rotational amount is set for each length of the telescopic beam 50. , Stored in the storage unit 65. The calculation unit 66 is provided to calculate the difference between the reference rotation amount corresponding to the length of the telescopic beam 50 measured by the measurement unit 62 and the rotation amount detected by the detection unit 61.

  The display unit 64 includes a liquid crystal display device. Further, under the control of the controller 63, the display unit 64 rotates the mast hoisting winch 35 to the operator by the difference calculated by the calculation unit 66, and sets the reference rotation amount corresponding to the length of the telescopic beam 50. A display prompting the user to set is displayed. The display unit 64 is not only newly provided, but may also be used as a display unit of an existing moment limiter device.

  Next, the assembly procedure when assembling the crawler crane 1 at the work site using the weight lifting amount adjusting device 60 will be described with reference to FIGS. 3 to 6 in addition to FIGS.

  Now, as shown in FIG. 1, the crane maker manufactured the crawler crane 1 and has finished the inspection of the product. At the time of this product inspection, when the load W is lifted by the lifting tool 22, the rotation amount of the mast hoisting winch 35 in a state where the counterweight carriage 40 is lifted from the ground by a predetermined dimension S is detected by the detection unit 61, and the reference rotation amount is stored in the storage unit 65. Is remembered as At this time, since the rotation amount of the mast hoisting winch 35 in a state where the counterweight carriage 40 is lifted from the ground by a predetermined dimension S varies depending on the length of the telescopic beam 50, the reference rotational amount is the same as the length of the telescopic beam 50. And stored in the storage unit 65.

  When the crawler crane 1 is disassembled and transported and assembled at the work site, the assembling procedure, particularly the procedure related to the operation of the mast hoisting winch 35, is performed through the steps shown in FIGS.

  That is, FIG. 3 shows a process in which the assembly of the crawler crane 1 is almost finished and the lower end of the hanger line 36 is lifted and connected to the link on the counterweight carriage 40 side. At that time, the mast hoisting rope 34 is wound up by the mast hoisting winch 35 and the mast 17 is tilted backward.

  Subsequently, as shown in FIG. 4, the telescopic beam 50 is changed to a desired length. FIG. 4 shows a state in which the length of the telescopic beam 50 is changed from the state shown in FIG. At that time, the mast hoisting rope 34 is wound up by the mast hoisting winch 35 and the mast 17 is tilted backward. When the length of the telescopic beam 50 is changed short, the mast hoisting rope 34 is fed out by the mast hoisting winch 35 and the mast 17 is raised forward.

  Next, the mast hoisting winch 35 is rotated in accordance with the instruction content displayed on the display unit 64 of the weight floating amount adjusting device 60, and the rotation amount is set to a reference rotation amount corresponding to the length of the telescopic beam 50. At that time, when the mast hoisting rope 34 is not loosened, as shown in FIG. 5, the mast hoisting winch 35 is rotated in the feeding direction, and the mast hoisting rope 34 is set to the reference rotation amount in a loose state. The

  Thereafter, the hoisting rope 23 is temporarily drawn out by the take-up winch 23 to suspend the hanging tool 22 to near the ground, and the luggage W is suspended from the hanging tool 22 in this state. Subsequently, as shown in FIG. 6, the load W is lifted by winding the hoisting rope 21 with the winding winch 23. At that time, the mast 17 rises forward as much as the mast hoisting rope 34 is loosened in the previous step, and the counterweight carriage 40 is lifted from the ground by a predetermined dimension S.

  As described above, the weight lifting amount adjusting device 60 includes the detection unit 61 that detects the rotation amount of the mast raising / lowering winch 35 and the mast raising / lowering in a state in which the separation type weight (counterweight carriage) 40 is lifted from the ground by a predetermined dimension S in advance. A storage unit 65 that stores the rotation amount of the winch 35 as a reference rotation amount, a calculation unit 66, and a display unit 64 are provided. When the crawler crane 1 is assembled at the work site, the difference between the rotation amount of the mast hoisting winch 35 detected by the detection unit 61 and the reference rotation amount stored in the storage unit 65 is calculated by the calculation unit 66. The display unit 64 prompts the operator to rotate the mast hoisting winch 35 by the amount corresponding to the difference and set it to the reference rotation amount. When the operator rotates the mast hoisting winch 35 based on the prompt of the display unit 64 and sets the rotation amount to the reference rotation amount, the rotation amount of the mast hoisting winch 35 is appropriately set when the assembly at the work site is completed. Can be set. Thereafter, when the load W is lifted by the lifting tool 22, it is possible to easily realize a state in which the separation-type weight 40 is lifted from the ground by a predetermined dimension S.

  In particular, in the case of the present embodiment, the separation-type weight 40 is a counterweight carriage, and the length of the counterweight carriage 40 and the rear portion of the upper swing body 14 of the crane body 10 can be changed (more specifically, can be extended and contracted). They are connected by a telescopic beam 50 as a connecting beam. In this case, the reference rotation amount of the mast hoisting winch 35 in a state in which the counterweight carriage 40 is lifted from the ground by a predetermined dimension S varies depending on the length of the telescopic beam 50.

  Corresponding to this, the weight lifting amount adjustment device 60 of the present embodiment further includes a measuring unit 62 that measures the length of the telescopic beam 50, and the reference rotation amount is set for each length of the telescopic beam 50. And stored in the storage unit 65. The calculation unit 66 is provided to calculate the difference between the reference rotation amount corresponding to the length of the telescopic beam 50 measured by the measurement unit 62 and the rotation amount detected by the detection unit 61. Therefore, the calculation unit 66 calculates a difference between the reference rotation amount corresponding to the length of the telescopic beam 50 and the rotation amount of the mast hoisting winch 35 detected by the detection unit 61, and the display unit 64 calculates the difference. Only the operator is required to rotate the mast hoisting winch 35 and set it to the reference rotation amount. As a result, it is possible to easily realize a state in which the counterweight carriage 40 is lifted from the ground by a predetermined dimension S corresponding to the length of the telescopic beam 50.

  In addition, this invention is not limited to the said embodiment, A various other form is included. For example, in the above-described embodiment, the display unit 64 of the weight lift adjustment device 60 prompts the operator to rotate the mast undulation winch 35 by the difference calculated by the calculation unit 66 and set it to the reference rotation amount. Configured. However, according to the present invention, the display unit 64 displays a switch for setting the reference rotation amount together with this display, and when the operator presses this switch, the mast hoisting winch 35 is automatically rotated and the reference rotation amount is set. You may comprise so that it may set to. Further, instead of the display unit 64 or in combination with the display unit 64, the mast undulating winch 35 is provided to the operator by the difference calculated by the calculation unit 66 with the sound of another notification unit, specifically a speaker. Of course, it may be configured to prompt the user to set the reference rotation amount.

  In the above embodiment, the case where the counterweight carriage 40 having the wheels 41 is used as the separation-type weight 40 that is lifted from the mast 17 and arranged behind the upper swing body 14 is described. The present invention can be similarly applied to a case where a pallet weight in which a weight is mounted on a pallet or other separate type weight is used instead of the counterweight carriage 40.

  Further, in the above-described embodiment, the gantry 18 is provided at the rear part of the upper swing body 14, and the top of the gantry 18 and the tip of the mast 17 are connected via the mast guy line 31 and the mast hoisting rope 34. The configuration in which one end portion is wound around the mast undulating winch 35 provided at the proximal end portion of the gantry 18 has been described. However, the present invention is not limited to this, and as in Patent Document 1, a base end of a columnar mast different from the lattice type mast is connected to the upper swing body so as to be able to undulate, and the tip of the columnar mast and the lattice type mast are connected. One end of the mast hoisting rope that is wound between the spreader on the tip side of the columnar mast and the spreader on the rear side of the upper swing body is provided at the rear of the upper swing body. The same configuration can be applied to a structure wound around a mast hoisting winch.

  In addition, in the above-described embodiment, the separation type weight 40 and the rear portion of the upper swing body 14 are connected using the telescopic beam 50 whose length can be expanded and contracted. A single unit does not have an expansion / contraction function, and may be configured to be connected using a connecting beam whose length can be changed by adding or removing members.

  Of course, the present invention can be applied not only to the crawler crane 1 as in the above embodiment but also to an all-terrain crane or other mobile cranes.

1 Crawler crane (mobile crane)
DESCRIPTION OF SYMBOLS 10 Crane main body 12 Lower traveling body 14 Upper turning body 16 Boom 17 Mast 22 Lifting tool 24 Boom guy line 27 Boom hoisting rope 35 Mast hoisting winch 40 Counterweight dolly (separate weight)
41 Wheel 50 Telescopic beam (Linked beam)
60 Weight lift adjustment device 61 Detection unit 62 Measurement unit 63 Controller 64 Display unit (notification unit)
65 Storage unit 66 Calculation unit W Luggage

Claims (5)

An upper swing body that is pivotably mounted on the lower traveling body, a boom whose base end is supported so as to be raised and lowered at the front of the upper swing body, and a hanging tool that is suspended from the tip of the boom, A mast whose base end is supported by the upper swinging body at a position rearward of the base end of the boom and whose tip is connected to the tip of the boom via a boom guy line and a boom hoisting rope, and the mast A mast hoisting winch to be moved, and a separation-type weight suspended from the mast and arranged behind the upper swing body, and configured to lift the separation-type weight from the ground when a load is lifted by the lifting tool A weight lift adjustment device for a mobile crane,
A detection unit for detecting a rotation amount of the mast undulation winch;
A storage unit that stores in advance a rotation amount of the mast hoisting winch in a state where the separation type weight is lifted from the ground by a predetermined dimension as a reference rotation amount;
A calculation unit that calculates a difference between the rotation amount detected by the detection unit and the reference rotation amount when the mobile crane is assembled at a work site;
A weight lifting amount of a mobile crane, comprising: a notifying unit that urges an operator to rotate the mast hoisting winch by the difference calculated by the calculating unit and set it to the reference rotation amount Adjustment device.   The weight lifting amount adjusting device for a mobile crane according to claim 1, wherein the separation-type weight and the rear part of the upper swing body are connected by a connecting beam whose length can be changed. A measuring unit for measuring the length of the coupled beam;
The reference rotation amount is set for each length of the connection beam, and is stored in the storage unit,
The movement according to claim 2, wherein the calculation unit is provided to calculate a difference between a reference rotation amount corresponding to a length of the coupled beam measured by the measurement unit and a rotation amount detected by the detection unit. -Type crane weight lift adjustment device.   The weight lifting amount adjusting device for a mobile crane according to any one of claims 1 to 3, wherein the separation-type weight is a counterweight carriage having wheels. An upper swing body that is pivotably mounted on the lower traveling body, a boom whose base end is supported so as to be raised and lowered at the front of the upper swing body, and a hanging tool that is suspended from the tip of the boom, A mast whose base end is supported by the upper swinging body at a position rearward of the base end of the boom and whose tip is connected to the tip of the boom via a boom guy line and a boom hoisting rope, and the mast A mast hoisting winch to be moved, and a separation-type weight suspended from the mast and arranged behind the upper swing body, and configured to lift the separation-type weight from the ground when a load is lifted by the lifting tool A weight lift adjustment method for a mobile crane,
The mobile crane detects a rotation amount of the mast hoisting winch, and stores a rotation amount of the mast hoisting winch in a state where the separation type weight is lifted from the ground in advance as a reference rotation amount. Department and
A method of adjusting a weight lifting amount of a mobile crane, wherein the rotation amount detected by the detection unit when the mobile crane is assembled at a work site is set as the reference rotation amount.

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