JP2020045250A - Mobile crane and assembling method of mobile crane - Google Patents

Abstract

To improve working efficiency by performing accurate alignment when a multistage boom is stretched to fit the boom base end part to the boom cylinder mounting portion of an upper revolving body.SOLUTION: Provided is an assembling method of a mobile crane that mounts a boom base end portion of a multistage boom mounted on a boom transportation platform in a manner of capable of rising at a boom mounting portion of an upper swing structure, which comprises both a first positioning step for aligning the positions in the height, the right-left direction, and the front-rear direction and a second positioning step for matching the right-left inclinations of the upper swing body and the multi-stage boom between first and second positioning portions provided on the side of the upper swing body and two positioning members provided opposite to the first and second positioning portions on the side of the base for boom transporting.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a mobile crane and a method for disassembling the mobile crane.

When transporting a mobile crane, it may be disassembled into an upper revolving unit and a boom and transported due to transportation restrictions. In this case, after the upper swing body and the boom are respectively carried into the work site, the boom is attached to the upper swing body again.
As a method of attaching the boom to the upper revolving structure, there is a method of assembling the boom by lifting it with an auxiliary crane, but this method requires a large occupied space when disassembling and assembling the swivel frame and the boom because the auxiliary crane is arranged. Is done.

Therefore, the following method is known in which a boom is attached to the upper swing body without using an auxiliary crane.
A multi-stage boom will be mounted on a boom transport stand such as a trailer. The boom transport pedestal is provided with a boom slide for adjusting the height of the multi-stage boom. The hydraulic pressure for boom expansion and contraction is supplied to the multi-stage boom, and the base boom of the multi-stage boom is brought closer to the upper revolving unit by extending the boom. Adjustment of the boom mounting portion of the upper revolving unit and the base boom of the multi-stage boom are performed in the vertical, horizontal, and vertical positions by rotating the boom transport base and adjusting the boom slide portion. Then, the boom mounting portion of the upper revolving structure and the base end side of the base boom of the multi-stage boom are assembled so that the multi-stage boom can be raised and lowered with respect to the upper revolving structure (for example, see Patent Document 1).

JP-A-2005-221703

  In the method described in Patent Literature 1, it is difficult to position the center axis of the base boom on the center axis of the base boom mounting portion set on the upper rotating body before extending the base boom of the multi-stage boom. There is a very high possibility of interfering with other members on the way. For this reason, it is necessary to repeat the extension of the base boom many times, and the work efficiency is low.

  According to one aspect of the present invention, a method of assembling a mobile crane includes a method of assembling a mobile crane, wherein a boom base end of a multi-stage boom mounted on a boom transport gantry is movably mounted on a boom mounting portion of an upper swing body. An assembling method, comprising: first and second positioning portions provided on the upper revolving body side; and two points provided on a boom transport gantry side facing the first and second positioning portions. The method includes a first positioning step of adjusting the position of the member in the height, left, right, front and rear directions, and a second positioning step of adjusting the left and right inclinations of the upper swing body and the multistage boom.

  ADVANTAGE OF THE INVENTION According to this invention, the position alignment of the boom cylinder attachment part of an upper revolving structure and the boom base end part of the multistage boom mounted on the boom transport stand becomes accurate, and work efficiency can be improved.

It is a side view of a mobile crane showing one embodiment of the present invention. It is a side view of the mobile crane from which the multistage boom in FIG. 1 was removed. It is a figure which shows the base end vicinity of a base boom, (a) is the figure which looked at the base boom from the base end side, (b) is the figure which looked at the base end part of the base boom from the side. It is a side view of a boom head holding structure and its vicinity. It is sectional drawing of a boom slide structure and its vicinity. (A) is a perspective view of a boom support stand, (b) is a sectional view taken along the line VIb-VIb of (a). FIGS. 3A and 3B are cross-sectional views of a boom support for illustrating a structure in which a guide bar is retracted, wherein FIG. 3A illustrates a state where the guide bar is stored, and FIG. 3B illustrates a state where the guide bar is pulled out. It is the top view which looked at the upper revolving superstructure from the front. (A) is a perspective view of the vicinity of the first and second positioning portions provided on the upper rotating body, and (b) and (c) respectively show the first and second positioning portions viewed from the front. FIG. (A), (b) is a figure which shows the modification of a 1st, 2nd positioning part. It is a side view which shows the positional relationship of the laser light source provided in the multistage boom, and an upper revolving superstructure. FIG. 12 is a view of FIG. 11 as viewed from above. It is a side view which shows the initial process of assembling a multistage boom to a crane main body. FIG. 14 is a side view showing a step subsequent to FIG. 13. FIG. 15 is a side view showing the next step of FIG. 14. FIG. 16 is a side view showing the next step of FIG. 15.

Hereinafter, an embodiment of a mobile crane and a mobile crane disassembly method according to the present invention will be described with reference to the drawings.
FIG. 1 is a side view of a mobile crane showing one embodiment of the present invention, and FIG. 2 is a side view of the mobile crane with the multi-stage boom shown in FIG. 1 removed.
The mobile crane 10 includes a crane main body 11 and a multi-stage boom 4 which is vertically rotatable with respect to the crane main body 11, in other words, is mounted so as to be able to undulate.
In the following description, the front-back direction, the up-down direction, and the left-right direction (see FIG. 3 and the like) are as illustrated.

  The crane main body 11 includes a lower traveling body 1 and an upper revolving superstructure 3 that is rotatably provided on the lower traveling body 1 via a revolving wheel 21. The upper swing body 3 includes a swing frame 3a. A front drum 5 and a rear drum 6 are mounted on the revolving frame 3a. On the left side of the crane main body 11, an operator cab 82 and a building cover 83 are arranged. On the right side of the crane main body 11, a building cover 84 (see FIG. 8) is arranged.

  The undercarriage 1 has a jack-up 22 (see FIG. 11 and the like) and side frames 23 connected to the left and right sides of the jack-up 22. The crawler belt 1a is mounted on the side frame 23.

  A boom mounting portion 31 that rotatably supports the multi-stage boom 4 is provided on a main frame 3b that forms a part of the revolving frame 3a. The boom mounting section 31 is provided with a boom pin insertion hole 31a (see FIG. 2) for inserting a boom pin 81 (see FIG. 1). The boom pin 81 is a shaft-shaped member for rotatably supporting the multi-stage boom 4 at the boom mounting portion 31 of the main frame 3b. Further, an up-and-down boom cylinder 7 for raising and lowering the multi-stage boom 4 is attached to the main frame 3b.

  The multi-stage boom 4 (hereinafter, also simply referred to as “boom”) is a telescopic boom that can be extended and retracted, and is provided with respect to the base boom 41 on the base end side, in other words, the base boom 41 on the rear end side. It is a multi-stage boom of at least two stages of the inner cylinder 45 which is a boom on the distal end side which can be extended and contracted. That is, the boom 4 is a base-side boom that is a base-side boom of the multi-stage boom and is the outermost cylinder that is positioned at the outermost side, and is capable of extending and contracting in the length direction on the inner peripheral side of the base boom 41. And a plurality of stages of inner cylinders 45 accommodated therein. At the base end of the base boom 41, a boom pin insertion hole 41a (see FIG. 3B) for inserting the boom pin 81 is provided. When the boom pin 81 is inserted into the boom pin insertion hole 31a of the boom mounting portion 31 and the boom pin insertion hole 41a of the base boom 41, as described above, the boom 4 can be turned on the upper swing body 3, that is, the shaft can be raised and lowered. Supported.

  On the lower surface side of the base boom 41, a cylinder rod mounting portion 42 (see FIG. 1) to which a tip end portion 72 (see FIG. 2) of the cylinder rod of the hoisting boom cylinder 7 is provided. The cylinder rod mounting portion 42 is provided with a pin insertion hole 42a (see FIG. 11 and the like) for inserting the cylinder pin 86.

  A cylinder pin insertion hole 72a (see FIG. 2) for inserting a cylinder pin 86 is provided at the tip end portion 72 of the cylinder rod of the up-and-down boom cylinder 7. The cylinder pin 86 is a shaft-shaped member for connecting the cylinder rod mounting portion 42 and the cylinder rod of the up-and-down boom cylinder 7, and is inserted into the rod insertion hole and the cylinder pin insertion hole 72a as described above.

  A boom head 46 is provided on the inner cylinder 45 located at the most distal end side among the plurality of stages of the inner cylinder 45. The boom head 46 is provided with sheaves 47 and 48 around which a hoisting rope (not shown) is wound. A short jib 49 is mounted in front of the sheave 47. The sheaves 47 and 48 are rotatably supported by shafts attached to the boom head 46, respectively.

3A and 3B are views showing the vicinity of the base end of the base boom, FIG. 3A is a view of the base boom viewed from the base end side, and FIG. 3B is a view showing the vicinity of the base end of the base boom from the side. FIG.
As shown in FIG. 3, the base boom 41 has a front surface 411 and a side surface 412 orthogonal to the front surface 411, and has a substantially rectangular cross-sectional shape. The boom 4 has a hydraulic cylinder 60 for expanding and contracting the inner cylinder 45 located closest to the base end with respect to the base boom 41 and a hydraulic cylinder (not shown) for expanding and contracting adjacent inner cylinders 45 with each other. Is provided. To each of these hydraulic cylinders, pressure oil is supplied from a crane main body 11 via a hydraulic hose (not shown) to extend and retract the boom 4. Therefore, near the base end of the base boom 41, a connection portion 61 of a hydraulic hose is provided.

  In the boom 4 of the present embodiment, the base boom 41 is expanded and contracted when the crane body 11 and the boom 4 are disassembled and assembled, as described later. At this time, pressure oil is supplied from the crane main body 11 to the hydraulic cylinder 60 via a hydraulic hose dedicated to disassembly and assembly not shown in FIG. Therefore, near the base end of the base boom 41, a connecting portion 62, which is different from the connecting portion 61 and is connected to the above-described hydraulic hose dedicated for disassembly and assembly, is provided. The connection portion 62 has a connection portion 62a for supplying pressure oil for extending the hydraulic cylinder 60 and a connection portion 62b for supplying pressure oil for retracting the hydraulic cylinder 60.

  In the mobile crane 10 configured in this manner, the mobile crane 10 is disassembled into the crane main body 11 and the boom 4 due to restrictions on the weight and length in transportation, and separately transported, and assembled again at the work site.

FIG. 4 is a side view of the boom head holding structure and its vicinity.
When assembling the boom 4 to the crane main body 11, as described later, the boom 4 is mounted on a boom transport gantry 201 (see FIG. 11 and the like). At this time, the boom head 46 provided in the innermost cylinder 45 at the tip of the boom 4 is held by the boom head holding structure 110. The boom head holding structure 110 includes a support member 111 and a support bracket 112. Although not shown, a plurality of sheaves 47 are arranged along the longitudinal direction of the shaft member 113 that supports the sheave 47. The tip of the shaft member 113 projects from the left and right sides of the boom head 46. The support members 111 are arranged as a pair on the left and right of the boom head 46. The support member 111 is provided with a concave portion into which the shaft member 113 fits. The boom head 46 is held by the support member 111 by fitting left and right protruding portions of the boom head 46 of the shaft member 113 into recesses of the support member 111 and sandwiching the support bracket 112 from above.

FIG. 5 is a sectional view of the boom slide structure and its vicinity.
The boom slide structure 220 includes a lower frame 221, an upper frame 222, and a slide roller 223. The boom slide structure 220 is mounted on the boom support 210. The boom support 210 is mounted on a boom transport gantry 201 having wheels 202, such as a trailer, for example.

  The base boom 41 is placed on the slide roller 223. As will be described later, the base boom 41 is extended by pressurized oil. At this time, the base boom 41 moves on the slide roller while rolling the slide roller 223. On the lower surface of the base boom 41, an inclined surface that is inclined obliquely upward from the center in the left-right direction toward each side surface is provided. The slide roller 223 is attached to the upper frame 222 such that the outer peripheral surface is parallel to the inclined surface of the base boom 41. The lower frame 221, the upper frame 222, and the slide roller 223 are symmetrically arranged as a pair on the left and right. This symmetry plane is located at the same position as the center plane of the base boom 41 in the left-right direction. As shown in FIG. 6A, a plurality of boom slide structures 220 are arranged along the front-rear direction.

FIG. 6A is a perspective view of the boom support, and FIG. 6B is a cross-sectional view taken along the line VIb-VIb of FIG. 6A. 7A and 7B are cross-sectional views of the boom support for showing a structure in which the guide bar is protruded and retracted. FIG. 7A shows a state in which the guide bar is stored, and FIG. Indicates the status.
A guide bar 231 extending in the front-rear direction is accommodated in the boom support 210 so as to be able to protrude and retract. The guide bar 231 is provided as a pair in the left-right direction. The pair of guide bars 231 are arranged symmetrically with respect to the center plane in the left-right direction. As shown in FIG. 5, the symmetry plane of the pair of guide bars 231 is located at the same position as the symmetry plane of the base boom 41 and the boom slide structure 220.

  As shown in FIGS. 7A and 7B, a flange 232 is provided at one end on the front side of the guide bar 231. A plurality (four in the embodiment) of inner walls 233 provided with through holes 233 a through which the flange 232 of the guide bar 231 is inserted are formed in the boom support 210. A stopper 234 having a through hole larger than the outer diameter of the guide bar 231 and smaller than the outer diameter of the flange 232 is attached to each of the two inner walls 233 on the rear side. The stopper 234 can be formed of a resin such as nylon. In addition, the stopper 234 can be a bush having a cylindrical portion that fits into the through hole 233a of the inner wall 233. A female screw may be provided in the through hole 233 a of the inner wall 233, and a male screw may be provided in the stopper 234 so that the stopper 234 is screwed into the inner wall 233. The guide bar 231 can slide through the through holes 233 a of the two inner walls 233 in front and the through holes of the two stoppers 234 as guide holes, and partially pull out the boom support 210. The guide bar 231 is restricted from moving rearward at a position where the flange 232 contacts the second stopper 234 from the rear side.

FIG. 8 is a plan view of the upper swing body viewed from the front, and FIG. 9A is a perspective view of the vicinity of first and second positioning portions provided on the upper swing body, and FIG. 9) and FIG. 9 (c) are views of the first and second positioning portions viewed from the front, respectively.
FIG. 11 is a side view showing the positional relationship between the laser light source provided on the multi-stage boom and the upper swing body, and FIG. 12 is a view of FIG. 11 as viewed from above.
A front frame 51 and a side frame 52 are arranged between the operator's cab 82 and the building cover 84 in the lateral direction of the crane main body 11. First and second positioning portions 171 and 172 are provided on the front frame 51 and the side frames 52. The first positioning portion 171 includes a nameplate 171a provided on the front frame 51 and a nameplate 171b provided on the side frame 52, as shown in FIG. As shown in FIG. 9B, a vertical line 131a is marked on the nameplate 171a. As shown in FIG. 9C, a horizontal line 131b is marked on the nameplate 171b. An end line 131c is marked at the rear end of the horizontal line 131b. The same applies to the second positioning portion 172, which has a nameplate 172a provided on the front frame 51 and a nameplate 172b (not shown) provided on the side frame 52. A vertical line 132a is marked on the nameplate 172a. A horizontal line 132b (not shown) and an end line 132c (not shown) are marked on a name plate 172b (not shown).

  The end of the left guide bar 231 is aligned with the end line 131c of the name plate 171b, the center line in the left-right direction of the guide bar 231 is aligned with the vertical line 131a of the name plate 171a, and the center line of the guide bar 231 in the vertical direction is aligned with the name plate. 171b is aligned with the horizontal line 131b. Although not shown, the end of the right guide bar 231 is aligned with the end line 132c of the name plate 172b, and the center line of the guide bar 231 in the left-right direction is aligned with the vertical line 132a (not shown) of the name plate 172a. Next, the vertical center line of the guide bar 231 is aligned with the horizontal line 132b of the nameplate 172b. By doing so, the height, the left, right, front and rear positions of the crane main body 11 and the boom 4 match.

  As shown in FIG. 8, a rear frame 53 is disposed on the rear side of the crane main body 11 and near the boom mounting portion 31 in the front-rear direction. A third positioning portion 173 is provided on the rear frame 53. The third positioning portion 173 is, for example, marked by a double circle. The center in the left-right direction of the double circle is located coaxially with the center axis in the left-right direction of the boom 4 mounted on the crane main body 11, in other words, the base boom 41. The vertical center of the double circle is the same position as the height of a laser light source 240 (see FIG. 11), which will be described later.

  As shown in FIG. 11, a laser light source 240 is mounted below the base end of the boom 4. The laser light source 240 outputs a visible red or other laser beam. The diameter of the laser beam is substantially the same as the diameter of the double circle of the third positioning portion 173. The direction of the laser beam output from the laser light source 240 coincides with the center axis in the left-right direction of the mounting portion of the base boom 41 in the left-right direction. The vertical direction is the horizontal direction. Therefore, when the boom 4 is horizontally lowered, the vertical direction of the laser beam is parallel to the central axis of the base boom 41 in the vertical direction.

  As shown in FIG. 12, the center axes of the guide bars 231 in the left-right direction and the up-down direction are respectively positioned on the vertical lines 131a, 132a and the horizontal lines 131b, 132b of the first and second positioning portions 171 and 172, respectively. In the aligned state, the laser beam output from the laser light source 240 is aligned with the third positioning section 173. Thereby, the deviation of the left and right inclinations of the crane main body 11 and the base boom 41 is eliminated. Therefore, if the base boom 41 is extended, the base end portion of the base boom 41 goes straight to the boom mounting portion 31 of the crane main body 11 and does not interfere with other portions of the crane main body 11. Absent.

The shape of the third positioning portion 173 may be a pattern other than a double circle, such as a cross shape.
Further, the first and second positioning portions 171 and 172 can also use other patterns.

FIGS. 10A and 10B are views showing a modification of the first and second positioning portions.
As shown in FIGS. 10A and 10B, the front frame 51 is provided with a positioning portion 271 having a double circle pattern 271a. The side frame 52 is provided with a name plate 271b. The vertical centerline of the nameplate 271b coincides with the vertical centerline of the double circle pattern 271a. An end line 271c is marked on the nameplate 271b.
The end face of the guide bar 231 is aligned with the end line 271c, and the vertical center axis of the guide bar 231 is aligned with the vertical center of the double circle pattern 271a. The center axis of the guide bar 231 in the left-right direction is aligned with the center line of the double circle pattern 271a in the left-right direction. Even in this case, the same positioning as in the case shown in FIG. 9 can be performed.

One embodiment of a method for assembling a mobile crane will be described with reference to FIGS.
The boom 4 is mounted on a boom transport gantry 201 such as a trailer. The boom head 46 of the boom 4 is held by a boom head holding structure 110 mounted on a boom transport gantry 201. Further, the base end side of the base boom 41 of the boom 4 is supported by a plurality of boom slide structures 220 provided on a boom support 210 mounted on the boom transport gantry 201. In this state, the boom transport gantry 201 travels rearward and approaches the crane main body 11. The crane main body 11 is fixed by a jack-up 22. As shown in FIG. 12, the jack-up 22 includes four jacks 22a, and the vertical position, that is, the height position can be adjusted by lifting and lowering the jack 22a. This state is illustrated in FIG. Since the auxiliary crane is not used in the method for assembling the mobile crane according to the present embodiment, the work area required for the assembling can be a small area as shown by a dotted line R in FIG.

  As shown in FIGS. 11 and 12, the crane main body 11 and the boom transport gantry 201 are connected to the center axis of the boom 4 mounting portion of the crane main body 11 and the boom 4 mounted on the boom transport gantry 201. The center axis is aligned in the up-down direction and the left-right direction. For this reason, the boom transport gantry 201 moves toward the crane main body 11 from a direction in which the center axis of the boom 4 substantially coincides with the center axis of the assembly portion of the crane main body 11 of the boom 4.

  As shown in FIG. 14, a pair of guide bars 231 housed in the boom support 210 are pulled out toward the crane main body 11 side. As shown in FIG. 7B, the pair of guide bars 231 have a predetermined length set in advance by being pulled out until the flange 232 comes into contact with a stopper 234 attached to the inner wall 233 on the rear side. Thereby, the distance between the boom mounting portion 31 of the crane main body 11 and the base end of the boom 4 in the front-rear direction is set to a predetermined length.

As shown in FIG. 15, the boom transport gantry 201 is moved to the crane main body 11 side.
The boom transport gantry 201 is operated such that the rear end surface of the guide bar 231 coincides with the end lines 131c and 132c (not shown) of the first and second positioning portions 171 and 172. This alignment is performed visually by an operator.
The positioning of the boom mounting portion 31 of the crane body 11 and the base end of the boom 4 in the front-rear direction is performed at a position where the rear end surface of each guide bar 231 of the boom support 210 contacts the front frame 51. You may make it.

  Then, the four jacks 22a of the jack-up 22 are raised and lowered, and the crane body 11 is driven to rotate so that the center axes of the guide bars 231 in the left-right direction and the up-down direction are aligned with the first and second positioning portions 171, 172 are aligned with the vertical lines 131a and 132a and the horizontal lines 131b and 132b. This alignment is performed visually by an operator.

  Further, a laser beam is output from a laser light source 240 provided on the lower surface of the end portion of the base end of the boom 4, and the jack 22 a of the jack-up 22 is adjusted so that the projection pattern matches the third positioning portion 173. Is operated, and the crane main body 11 is turned. This alignment is also performed visually by an operator.

  When the positioning between the pair of guide bars 231 and the first and second positioning portions 171 and 172 and the positioning between the laser beam and the third positioning portion 173 are completed, the base boom 41 is moved to the crane main body 11. It extends toward the boom attachment part 31. The extension of the base boom 41 is performed by connecting a hydraulic hose dedicated for disassembly and assembly to the connection portions 62a and 62b provided near the base end of the base boom 41. The hydraulic hose of the crane main body 11 may be directly connected to the connection portion 61.

  When the base boom 41 is extended, the boom pin insertion hole 41a of the base boom 41 is aligned with the boom pin insertion hole 31a of the boom mounting part 31, as shown in FIG. Therefore, in this state, the boom pin 81 (see FIG. 1) is inserted. If the position of the boom pin insertion hole 41a of the base boom 41 and the position of the boom pin insertion hole 31a of the boom mounting portion 31 do not exactly match by simply extending the base boom 41, the position is finely adjusted by the jack 22a of the jack-up 22. After adjustment, the boom pin 81 is inserted into the boom pin insertion hole 41a and the boom pin insertion hole 31a of the boom mounting portion 31.

  After that, the pin insertion hole 42a of the cylinder rod attachment portion 42 and the cylinder pin insertion hole 72a at the tip of the cylinder rod of the hoisting boom cylinder 7 are aligned, and the cylinder pin 86 is inserted (see FIG. 1).

  Further, the support bracket 112 of the boom head holding structure 110 is removed from the support member 111. Thereby, the attachment of the boom 4 to the crane main body 11 is completed.

  The removal of the boom 4 from the crane main body 11 can be performed by the above-described procedure for assembling the boom 4 to the crane main body 11 in reverse order. Therefore, the description of the procedure for removing the boom 4 from the crane main body 11 will be omitted.

According to the one embodiment, the following effects are obtained.
(1) The first, second positioning portions 171 and 172 provided on the front surface of the crane main body 11 and the pair of guide bars 231 provided behind the boom transport gantry 201 are moved in height, left and right, and front and rear directions. And a second positioning step of adjusting the left and right inclinations of the crane main body 11 and the multi-stage boom 4. Therefore, before the base boom 41 is extended, the height, left, right, front and back of the boom mounting portion of the crane main body 11 and the boom 4 mounted on the boom transport gantry 201 can be accurately positioned. Thereby, when extending the base boom 41 to the boom attachment part 31, the probability that the base end of the base boom 41 interferes with other parts of the crane main body 11 can be reduced. As a result, the work efficiency can be improved as compared with the conventional assembling method in which the extension of the base boom 41 is repeated to extend the base boom 41 to the boom mounting portion 31.

(2) The alignment between the laser beam and the third positioning section 173 is performed at a position closer to the boom mounting section 31 than the alignment between the first and second positioning sections 171 and 172 and the guide bar 231. For this reason, the accuracy of positioning is improved.
(3) Positioning to the third positioning section 173 is performed using a laser beam. When the positioning with the third positioning portion 173 is performed by the guide bar 231 in the same manner as the positioning with the first and second positioning portions 171 and 172, the drawing length of the guide bar 231 becomes longer, and The structure of the boom transport gantry 201 such as a place and a holding structure becomes complicated, and as a result, work efficiency is reduced. That is, since the positioning is performed by the laser beam when the distance between the positioning members is long, the working time can be further reduced.

  In the above-described embodiment, the positioning with respect to the third positioning section 173 has been exemplified as a method of performing the alignment using a laser beam. However, instead of this method, the center axis of the boom 4 mounted on the boom transport gantry 201 and the center axis of the up-and-down boom cylinder 7 provided on the crane main body 11 coincide with each other in the projection projected from above. The position can be adjusted by the following method.

  In the above-described embodiment, the method of assembling the boom 4 to the crane main body 11 in a state where the side frame 23 and the crawler belt 1a are not attached to the jack-up 22 has been exemplified. However, the boom 4 may be assembled to the crane main body 11 in which the side frame 23 and the crawler belt 1a are mounted on the jack-up 22.

  The present invention is not limited to the contents shown in the above-described embodiment and modifications. Other embodiments that can be considered within the scope of the technical concept of the present invention are also included in the scope of the present invention.

Reference Signs List 3 upper revolving unit 4 multi-stage boom 7 up-and-down boom cylinder 10 movable crane 31 boom mounting part 171 first positioning part 172 second positioning part 173 third positioning part 201 boom transport gantry 231 guide bar (positioning member)
240 Laser light source 271 Positioning unit

Claims (5)

A method of assembling a mobile crane for mounting a boom base end of a multi-stage boom mounted on a boom transport gantry to a boom mounting portion of an upper revolving body so as to be able to undulate,
Heights of first and second positioning portions provided on the upper revolving unit side and two positioning members provided on the boom transporting gantry side facing the first and second positioning portions. A first positioning step of aligning positions in the left, right, front and rear directions;
A second positioning step of adjusting the left and right inclinations of the upper revolving superstructure and the multi-stage boom, and a method of assembling a mobile crane. The method for assembling a mobile crane according to claim 1,
The second positioning step includes providing a laser beam emitted from a laser light source provided on the multi-stage boom and a position closer to the boom mounting portion than the first and second positioning portions of the upper rotating body. A method for assembling a mobile crane, comprising a step of aligning the third positioning portion with the second positioning portion. The method for assembling a mobile crane according to claim 1,
An up-and-down boom cylinder having a central axis coaxial with the central axis of the boom mounting portion in a projection projected from above is mounted on the upper revolving structure to which the multi-stage boom is mounted,
The method of assembling a mobile crane, wherein the second positioning step includes a step of aligning a center axis of the multi-stage boom mounted on the boom transport gantry with a center axis of the hoisting boom cylinder. A boom attachment portion, the boom attachment portion, comprising an upper revolving structure having a multi-stage boom to which a boom base end is attached so as to be able to undulate,
Further, the upper revolving superstructure is provided with first and second two alignment portions for aligning the boom base end of the multi-stage boom with the boom mounting portion in height, left and right, and front and rear directions. A mobile crane, comprising: the upper revolving superstructure; and a third positioning unit that adjusts the left and right inclinations of the multistage boom. The mobile crane according to claim 4,
The third positioning portion is provided at a position closer to the boom mounting portion in the front-rear direction than the first and second positioning portions,
A mobile crane, further comprising a laser light source for aligning the multi-stage boom with the third positioning portion.

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