How to lower heavy machinery

Abstract

To provide a new method for lowering and carrying a heavy machine from a temporary ground surface into an underground space.SOLUTION: A method for lowering a heavy machine 50 from a temporary ground 30 to an underground floor surface 40 by using a lifting device 1 installed on the temporary ground 30 composed of a plurality of lining plates 31 comprises the steps of: installing a temporary receiving girder 20 so as to be laid across an opening part 34 of the temporary ground 30; placing a stage 6 of the lifting device 1 on the temporary receiving girder 20; carrying the heavy machine 50 on the stage 6 in a state of being placed on the temporary receiving girder 20; lifting the stage 6 with the heavy machine 50 on it by the lifting device 5 of the lifting device 1 to lift the stage 6 off the ground; removing the temporary receiving girder 20 from the opening 34 in a state where the stage 6 is not grounded; and lowering the stage 6 with the heavy machine 50 placed thereon to the underground floor surface 40 through the opening part 34 by the lifting device 5 after the temporary receiving girder 20 is removed.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a method for lowering heavy machinery from a temporary ground surface formed by a covering plate to an underground floor surface. [Background technology]

[0002] For example, when constructing an underground structure under a road or the like, a lining plate can be used as a temporary ground (e.g., a temporary road surface) in the area corresponding to the ground. This lining plate is intended to close the top opening of a space (underground space) formed by excavation underground, and can be laid on a lining girder (lining support girder) installed above the underground space. In this regard, Patent Document 1 discloses that a hoisting crane is installed on a temporary floor (corresponding to the temporary ground mentioned above) constructed by laying covering plates on floor joists, and that this crane is used to hoist and lower various materials underground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2-33021 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, it is conceivable to use an existing large crane to hoist heavy machinery used in construction within the underground space from the temporary ground into the underground space. However, to hoist and lower heavy machinery weighing, for example, about 30 tons, a large crane of at least about 120 tons would be required. Even if such a large crane were to be placed on the temporary ground, there is a risk that the weight of the large crane would make the temporary ground insufficient in strength, necessitating reinforcement. Furthermore, for example, in railway construction, construction may be carried out in a narrow yard adjacent to the tracks, and in such cases it has been difficult to place such a large crane in the yard.

[0005] In view of the above circumstances, the present invention aims to propose a new method for lowering heavy machinery from a temporary ground surface into an underground space. [Means for solving the problem]

[0006] Therefore, the method for lowering heavy machinery according to the present invention is a method for lowering heavy machinery from the temporary ground to the underground floor using a lifting device installed on a temporary ground consisting of a plurality of covering plates. The lifting device includes a portal frame erected on the temporary ground, a lifting device attached to the upper beam of the portal frame, and a stage that can be raised and lowered by the lifting device and that can pass up and down through an opening in the temporary ground. The method for lowering heavy equipment according to the present invention includes a temporary support girder installation process for installing a temporary support girder so that it spans an opening in the temporary ground; a stage placement process for placing a stage on the temporary support girder; a heavy equipment installation process for transporting heavy equipment onto the stage placed on the temporary support girder; a ground clearance process for raising the stage with the heavy equipment placed on it using a lifting device to remove the stage from the ground; a temporary support girder removal process for removing the temporary support girder from the opening in the temporary ground while it has been raised; and a lowering process for lowering the stage with the heavy equipment placed on it using a lifting device after the temporary support girder has been removed, thereby passing it through the opening in the temporary ground and lowering it to the underground floor. In the temporary support girder removal process, the temporary support girder is removed from the opening in the temporary ground by sliding it in the longitudinal direction of the temporary support girder. Here, the length of the temporary support girder is at least twice the width of the opening in the temporary ground. [Effects of the Invention]

[0007] According to the present invention, a new and unprecedented method can be used to lower heavy machinery from the temporary ground surface into an underground space. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a front view of a lifting device according to an embodiment of the present invention; [Figure 2] FIG. 10 is a side view of the lifting device in the embodiment. [Figure 3] Cross section AA of Figure 2 [Figure 4] 10A and 10B are diagrams showing a method of installing a temporary support beam and a stage in the embodiment; [Figure 5]10A and 10B are diagrams showing a method of installing a temporary support beam and a stage in the embodiment; [Figure 6] FIG. 10 shows a method for lowering the heavy equipment in the embodiment. [Figure 7] FIG. 10 shows a method for lowering the heavy equipment in the embodiment. [Figure 8] FIG. 10 shows a method for lowering the heavy equipment in the embodiment. [Figure 9] FIG. 10 shows a method for lowering the heavy equipment in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0010] 1 and 2 are a front view and a side view of a lifting device 1 according to one embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. Here, FIG. 1 corresponds to the cross-section taken along line BB in FIG. 2. In addition, in FIG. 3, for the sake of simplicity, the illustration of a lifting hook 5d and a lifting tool 5f of a lifting device 5, which will be described later, is omitted. For the sake of convenience, up and down, front and back, and left and right are defined as shown in FIGS. 1 to 3, and therefore FIG. 2 is a left side view of the lifting device 1. It goes without saying that the dimensions described below are merely for illustrative purposes and are not limited to those dimensions.

[0011] The lifting device 1 is installed on a temporary ground 30. The temporary ground 30 is made up of a plurality of covering plates 31. In plan view, the covering plates 31 are rectangular in shape with short sides (e.g., about 1 m) along the front-to-rear direction and long sides (e.g., about 3 m) along the left-to-right direction, and are made of, for example, steel. The temporary ground 30 and the covering plates 31 that make it up are intended to close the top opening of a space (underground space) 32 that has been excavated underground, for example.

[0012] The temporary ground 30 is formed by laying multiple lining plates 31 on multiple lining girders (lining support girders) 33. The multiple lining girders 33 extend parallel to each other at intervals in the left-right direction, and each lining girder 33 extends in the front-to-rear direction. Each lining plate 31 is laid so as to straddle adjacent lining girders 33 at intervals in the left-to-right direction. The lining girders 33 are made of, for example, H-shaped steel or I-shaped steel and have an upper flange, a lower flange, and a web. Note that the lining girders 33 can be directly or indirectly fixed to and supported by temporary support piles (not shown) that have been driven into the ground in advance. These temporary support piles may form an earth retaining wall (for example, they may be support piles in an earth retaining wall formed by a support pile and horizontal sheet pile construction method). In this embodiment, for adjacent covering girders 33 in the left-right direction, there is a gap of approximately 3 m between each web, a gap of approximately 2.7 m between each upper flange, and a gap of approximately 2.7 m between each lower flange.

[0013] An opening 34 (see FIG. 4(A) described later) having a rectangular shape in plan view is formed in the temporary ground 30. The opening 34 can be formed, for example, by removing a plurality of covering plates 31 that constitute the temporary ground 30. In this embodiment, the opening 34 is formed by removing six covering plates 31 that constitute the temporary ground 30 and are arranged in the front-to-rear direction. Referring to FIG. 4(A), in this embodiment, the length (opening width) W0 of the opening 34 in the left-to-right direction is, for example, about 3 m, and the length (opening length) L0 of the opening 34 in the front-to-rear direction is, for example, about 6 m. The opening 34 communicates the space above the temporary ground 30 with the underground space 32. Note that, referring to FIG. 4(A), in this embodiment, the distance (narrowest width) W1 between the upper flanges of the lining girders 33 located below the opening 34 is, for example, about 2.7 m. Similarly, the distance (narrowest width) W2 between the lower flanges of the lining girders 33 located below the opening 34 is, for example, about 2.7 m.

[0014] Returning to FIGS. 1 to 3, the lifting device 1 includes a frame 2, a floor beam 3, a height adjusting member 4, a lifting device 5, and a stage (base) 6. The frame body 2 is a so-called "tower" and comprises a front gate-shaped frame 8, a rear gate-shaped frame 9, an upper beam 10, a left reinforcement 11, a right reinforcement 12, and a rear reinforcement 13.

[0015] The front portal frame 8 is composed of a pair of left and right legs 8a extending in the vertical direction, and an upper beam 8b extending in the horizontal direction with both left and right ends connected to the upper ends of these legs 8a. The rear gate-shaped frame 9 is composed of a pair of left and right legs 9a extending in the vertical direction, and an upper beam 9b extending in the horizontal direction with both left and right ends connected to the upper ends of these legs 9a. The legs 8a, 9a and upper beams 8b, 9b that make up the portal frames 8, 9 are made of, for example, H-shaped steel. The vertical length of the legs 8a, 9a is, for example, about 4 m. The horizontal length of the upper beams 8b, 9b is, for example, about 5 m.

[0016] The front gate frame 8 and the rear gate frame 9 are arranged with a gap between them in the front-rear direction. A pair of left and right upper beams 10 extending in the front-to-rear direction are bridged between the upper surface of the upper beam 8b of the front portal frame 8 and the upper surface of the upper beam 9b of the rear portal frame 9. The front end of the upper beam 10 is fixed to the upper surface of the upper beam 8b of the front portal frame 8, and the rear end of the upper beam 10 is fixed to the upper surface of the upper beam 9b of the rear portal frame 9. The length of the upper beam 10 in the front-to-rear direction is, for example, about 6 m. The upper beam 10 is made of, for example, H-shaped steel.

[0017] A pair of upper and lower left reinforcing members 11 extending in the front-rear direction are bridged between the left leg 8a of the front portal frame 8 and the left leg 9a of the rear portal frame 9. A pair of upper and lower right reinforcing members 12 extending in the front-rear direction are bridged between the right leg 8a of the front portal frame 8 and the right leg 9a of the rear portal frame 9. A pair of upper and lower rear reinforcing members 13 extending in the left-right direction are bridged between the pair of left and right leg portions 9a of the rear gate-shaped frame 9. The left reinforcement member 11, the right reinforcement member 12 and the rear reinforcement member 13 are made of, for example, H-shaped steel.

[0018] The upper beam 8b of the front portal frame 8 and the upper beam 9b of the rear portal frame 9 are located directly above the front end and rear end of the opening 34 in the temporary ground 30, respectively. In plan view, the front end of the opening 34 in the temporary ground 30 is located between the pair of left and right legs 8a of the front portal frame 8. In plan view, the rear end of the opening 34 in the temporary ground 30 is located between the pair of left and right legs 9a of the rear portal frame 9.

[0019] Between the lower end of each leg 8a, 9a of the portal frames 8, 9 and the temporary ground 30, there are interposed, in this order from bottom to top, a floor beam 3 and a height adjustment member 4. In other words, the portal frames 8, 9 are erected on the temporary ground 30 via the floor beam 3 and the height adjustment member 4. At least a portion of the floor girder 3 is placed on a covering plate 31 that defines an opening 34 in the temporary ground 30, and extends in the left-right direction. The floor girder 3 is arranged near the opening 34 in the temporary ground 30 so as not to cover the opening 34 in a plan view. The floor girder 3 is made of, for example, an H-shaped steel, and has an upper flange, a lower flange, and a web.

[0020] The height adjustment members 4 are interposed between the lower ends of the legs 8a, 9a of the portal frames 8, 9 and the floor beams 3, and are made, for example, of H-shaped steel extending in the left-right direction, and have an upper flange, a lower flange, and a web. The height adjustment members 4 are used to adjust the height of the portal frames 8, 9 relative to the temporary ground 30, and their dimensions are arbitrary. The height adjustment members 4 are also arranged so as not to cover the openings 34 of the temporary ground 30 in a plan view. If the height adjustment members 4 are not required, they may be omitted.

[0021] The floor girders 3 are arranged directly above the lining girders 33 so as to straddle adjacent lining girders 33 spaced apart in the left-right direction. This allows the load from each leg 8a, 9a of the portal frames 8, 9 to be distributed to multiple lining girders 33 via the floor girders 3. In other words, it is possible to prevent the load from each leg 8a, 9a of the portal frames 8, 9 from acting directly and intensively on the lining plate 31. The floor girders 3 can be arranged so as to straddle any two or more lining girders 33.

[0022] A pair of left and right lifting devices 5 are attached to each of the upper beams 8b, 9b of the portal frames 8, 9. In other words, the stage 6 can be suspended and supported at four points by the four lifting devices 5. In other words, the stage 6 can be suspended and supported at multiple points (multiple points) by the multiple lifting devices 5.

[0023] The lifting device 5 is, for example, a chain block. The lifting device 5 includes, for example, a drive unit 5b having an upper hook 5a, a linear member (for example, a chain) 5c that can be hoisted and lowered by the drive unit 5b, and a lifting hook 5d attached to the lower end of the linear member 5c. The lifting device 5 may be electric or manual.

[0024] Two mounting brackets 5e are provided on each of the upper beams 8b, 9b of the portal frames 8, 9, and an upper hook 5a of the lifting device 5 can be attached to each mounting bracket 5e. The lifting hook 5d of the lifting device 5 can be attached to the stage 6 via a lifting tool 5f.

[0025] The stage 6 has a layered structure in which multiple layers (two layers in this embodiment) are stacked vertically. The bottom layer of this layered structure includes multiple (two in this embodiment) suspension girders 15, and the top layer includes multiple (six in this embodiment) support girders 16. The suspension beam 15 and the support beam 16 are each made of, for example, an H-shaped steel, and have an upper flange, a lower flange, and a web.

[0026] The two suspension girders 15 extend in the front-rear direction in parallel with each other at a distance from each other in the left-right direction. In this embodiment, horizontal braces 17 are provided on the two suspension girders 15. The six support beams 16 extend in the left-right direction, parallel to each other and spaced apart from each other in the front-rear direction. In plan view, the suspension girders 15 and the support girders 16 are perpendicular to each other. The stage 6 is formed in a ladder shape by the suspension girders 15 and the support girders 16.

[0027] Brackets 18 for attaching the above-mentioned suspenders 5f are provided at both the front and rear ends of the suspension beam 15. Therefore, the stage 6 can be suspended and supported by the lifting device 5 at the locations on the suspension beam 15 where the brackets 18 are installed.

[0028] 4(A) and 5(C), the length L1 of the suspension girder 15 (length in the longitudinal direction, that is, the front-to-rear direction) is approximately equal to or slightly shorter than the opening length L0 of the opening 34 in the temporary ground 30. Furthermore, the length L2 of the support girder 16 (length in the longitudinal direction, that is, the left-to-right direction) is approximately equal to or slightly shorter than the distances (narrowest widths) W1, W2 between the flanges of the lining girders 33 located below the opening 34 in the temporary ground 30. Therefore, the stage 6 can be raised and lowered by winding up and down the linear member 5c of the lifting device 5, and can pass through the opening 34 of the temporary ground 30 in the vertical direction.

[0029] On the support beams 16 that constitute the stage 6, a heavy machine 50 (see Fig. 6(a) to Fig. 9(g) described later) can be placed.

[0030] In this embodiment, a plurality of (eleven in this embodiment) temporary support girders 20 are provided to span the opening 34 of the temporary ground 30 (see FIGS. 1 to 3). The temporary support girders 20 extend in the left-right direction and parallel to each other at intervals in the front-rear direction. The temporary support girders 20 are made of, for example, H-shaped steel, and have an upper flange, a lower flange, and a web.

[0031] 4(A) and 4(B), the length L3 of the temporary support girder 20 (the length in the left-right direction, i.e., the longitudinal direction) is at least twice the opening width W0 of the opening 34 in the temporary ground surface 30. In this embodiment, the length L3 of the temporary support girder 20 is, for example, about 6 m.

[0032] In this embodiment, before the heavy equipment 50 is placed on the stage 6, the stage 6 may be placed on the temporary support girder 20. This procedure will be described with reference to FIGS. Figures 4(a) to 5(c) show a method for installing the temporary support beam 20 and the stage 6. Here, Figures 4(a) to 5(c) are plan views similar to the above-mentioned Figure 3.

[0033] First, as shown in FIG. 4(a), a plurality of temporary support girders 20 are arranged and installed across an opening 34 in a temporary ground 30 formed as shown in FIG. 4(a), as shown in FIG. 4(b). Next, as shown in Figure 5 (c), two suspension girders 15 are placed on the temporary support girders 20, lined up so that they are perpendicular to the temporary support girders 20, and horizontal braces 17 are attached. After that, six support girders 16 are placed on the two suspension girders 15, lined up so that they are perpendicular to the suspension girders 15, so as to straddle them. Then, by fixing these suspension girders 15 and support girders 16 to each other and integrating them, the stage 6 can be placed on the temporary support girders 20.

[0034] 2 and 3, a slope 26 having an inclined surface 25 is installed on the temporary ground 30 so as to be adjacent to the front edge of the opening 34. The inclined surface 25 of the slope 26 has an upward gradient that increases from the front to the rear. The height of the rearmost part of the slope 26 (the height of the side of the slope 26 closest to the front edge of the opening 34) is approximately equal to the sum of the height of the stage 6 (the sum of the height of the suspension girders 15 and the height of the support girders 16) and the height of the temporary support girders 20.

[0035] In this embodiment, the total weight of the lifting device 1 and the temporary support girder 20 is, for example, about 15 tons. This is obviously much lighter than existing large cranes such as so-called 120-ton cranes (vehicle weight of which is, for example, about 80 tons).

[0036] Next, a method for lowering heavy equipment 50 from temporary ground 30 to underground floor 40 using lifting device 1 installed on temporary ground 30 will be explained using Figures 6 to 9 in addition to Figures 1 to 5 mentioned above. Figures 6(a) to 9(f) show a method for lowering the heavy machine 50. Here, Figures 6(a) to 9(f) are front views similar to Figure 1 described above.

[0037] First, as shown in FIG. 4(A), the temporary support girder 20 is installed so as to span the opening 34 of the temporary ground 30 (temporary support girder installation step). Next, as shown in FIG. 5(c), the stage 6 is placed on the temporary support beam 20 (stage placing step).

[0038] 6(A), the parts of the lifting device 1 other than the stage 6 are also installed on the temporary ground 30. The installation timing may overlap with the implementation timing of at least one of the temporary support girder installation process and the stage placement process described above. Alternatively, the installation timing may be shifted forward or backward so as not to overlap with the implementation timing of the temporary support girder installation process and the stage placement process described above.

[0039] In this embodiment, before the heavy machine 50 is carried onto the stage 6, the two lifting devices 5 attached to the upper beam 8b of the front portal frame 8 have their lower end lifting hooks 5d detached from the stage 6 and raised to a position where they will avoid the heavy machine 50 when the heavy machine 50 is carried in. In contrast, the two lifting devices 5 attached to the upper beam 9b of the rear portal frame 9 have their lower end lifting hooks 5d connected to the suspension beam 15 of the stage 6 via the lifting tools 5f and brackets 18.

[0040] Next, as shown in Fig. 6(a), heavy equipment 50 is carried onto the stage 6 placed on the temporary support girder 20 (heavy equipment carrying-in process). This heavy equipment carrying-in process involves heavy equipment 50 moving under its own power from the temporary ground 30 over the inclined surface 25 of the slope 26 to the top of the stage 6. In this embodiment, because the stage 6 is placed on the temporary support girder 20, wobbling of the stage 6 when the heavy equipment 50 is carried in can be suppressed.

[0041] Here, the heavy machine 50 will be described. The heavy machine 50 is, for example, a hydraulic excavator such as a backhoe, a pile driver, a bulldozer, or other construction machine. The heavy machine 50 also includes, for example, a base machine 53 having a lower traveling body 51 and an upper rotating body 52, and a work device 54 attached to the upper rotating body 52 via an arm (not shown). The lower traveling body 51 includes, for example, endless tracks (crawlers) 55 on both the left and right sides. The upper rotating body 52 is rotatably mounted on the upper part of the lower traveling body 51. The work device 54 is used for various tasks such as excavation, pile driving, and leveling. In this embodiment, the lower traveling body 51 includes the endless tracks 55, but may also include wheels such as tires. Here, it is preferable that the stage 6 is configured so that the suspension girders 15 are located directly below the endless tracks 55 or wheels on both the left and right sides of the lower traveling body 51 of the heavy machine 50.

[0042] Next, as shown in Figure 7 (c), for the two lifting devices 5 attached to the upper beam 8b of the front portal frame 8, the linear members 5c are lowered, and the lifting hooks 5d at their lower ends are attached to the lifting fixtures 5f, which are then connected to the suspension beams 15 of the stage 6 via brackets 18.

[0043] Next, as shown in FIG. 7(d), the stage 6 with the heavy machine 50 placed thereon is raised by the lifting device 5, thereby performing ground-raising of the stage 6 (ground-raising step).

[0044] Next, as shown in Figure 8 (e), with the stage 6 in a state where it has been cut off from the ground, the temporary support girders 20 are removed from the openings 34 of the temporary ground 30 (temporary support girder removal process). In this temporary support girder removal process, all of the temporary support girders 20 are removed from the openings 34 of the temporary ground 30 by sliding each temporary support girder 20 in the longitudinal direction relative to the temporary ground 30. Note that, although the present embodiment illustrates an example in which the temporary support girders 20 extending in the left-right direction are removed from the openings 34 of the temporary ground 30 by sliding them to the left, it goes without saying that the temporary support girders 20 may also be removed from the openings 34 of the temporary ground 30 by sliding them to the right in the opposite manner.

[0045] 8(f) and 9(g), the stage 6 carrying the heavy equipment 50 is lowered by the lifting device 5 to the underground floor 40 through the opening 34 in the temporary ground 30 (lowering process). A recess 41 capable of accommodating the stage 6 is pre-excavated in the underground floor 40 directly below the opening 34. Therefore, in the lowering process, the stage 6 is accommodated in the recess 41 in the underground floor 40. The recess 41 in the underground floor 40 has a rectangular shape in plan view, similar to the opening 34. The dimensions of each side of the rectangular shape of the recess 41 are approximately equal to or slightly larger than the dimensions of each side of the rectangular shape of the opening 34. The depth of the recess 41 is approximately equal to the height of the stage 6 (the sum of the heights of the suspension girders 15 and the support girders 16). Therefore, there is no need to install something like the aforementioned slope 26 on the underground floor surface 40.

[0046] In this way, the lifting device 1 installed on the temporary ground 30 can be used to lower the heavy equipment 50 from above the temporary ground 30 to the floor surface 40 underground.

[0047] The heavy machine 50 in this embodiment has a weight of, for example, about 30 tons. Conventionally, a large crane of at least about 120 tons was required to hoist and lower such a heavy machine 50, but in this embodiment, the heavy machine 50 can be hoisted and lowered using the lifting device 1 and temporary support girder 20, which are much lighter than the large crane.

[0048] The above has described a method for lowering heavy equipment 50 from above temporary ground 30 to underground floor 40 using lifting device 1, but it goes without saying that by reversing the order of the steps in this method, heavy equipment 50 can be raised from underground floor 40 to above temporary ground 30. In other words, lifting device 1 can be used to raise and lower heavy equipment 50.

[0049] According to this embodiment, the method for lowering heavy equipment 50 is to use a lifting device 1 installed on temporary ground 30 consisting of a plurality of covering plates 31 to lower heavy equipment 50 from above temporary ground 30 to the underground floor surface 40. Lifting device 1 comprises portal frames 8, 9 erected on temporary ground 30, lifting devices 5 attached to upper beams 8b, 9b of portal frames 8, 9, and a stage 6 that can be raised and lowered by lifting device 5 and that can pass up and down through opening 34 in temporary ground 30. The method for lowering the heavy equipment 50 includes a temporary support girder installation step of installing the temporary support girder 20 so that it spans the opening 34, a stage installation step of placing the stage 6 on the temporary support girder 20, a heavy equipment installation step of carrying in the heavy equipment 50 onto the stage 6 placed on the temporary support girder 20, a ground clearance step of raising the stage 6 with the heavy equipment 50 placed on it by the lifting device 5 to remove the temporary support girder 20 from the opening 34 with the stage 6 being raised to the ground, and a lowering step of lowering the stage 6 with the heavy equipment 50 placed on it by the lifting device 5 after the temporary support girder 20 has been removed, passing through the opening 34 and lowering to the underground floor surface 40. The lifting device 1 has a plurality of portal frames 8, 9, and a plurality of lifting devices 5 are attached to the upper beams 8b, 9b of each portal frame 8, 9, and the stage 6 is suspended and supported at multiple points by these lifting devices 5. This allows the lifting device 1 to have a lightweight and compact configuration.

[0050] Furthermore, according to this embodiment, in the temporary support girder removal process, the temporary support girder 20 is removed from the opening 34 by sliding it in the longitudinal direction of the temporary support girder 20. Here, the length L3 of the temporary support girder 20 is at least twice the opening width W0 of the opening 34. As a result, when removing (pulling out) the temporary support girder 20, more than half of the length of the temporary support girder 20 is always positioned above the temporary ground surface 30, thereby preventing the temporary support girder 20 from falling into the opening 34.

[0051] Furthermore, according to this embodiment, the heavy equipment carrying-in process includes the heavy equipment 50 traveling under its own power from the temporary ground 30 onto the stage 6. In particular, according to this embodiment, a slope 26 having an inclined surface 25 is installed on the temporary ground 30, and the heavy equipment carrying-in process includes the heavy equipment 50 traveling under its own power from the temporary ground 30 over the inclined surface 25 of the slope 26 onto the stage 6. As a result, even if there is a difference in elevation between the stage 6 and the temporary ground 30, the heavy equipment 50 can be smoothly carried in from the temporary ground 30 onto the slope 26 onto the stage 6.

[0052] Furthermore, according to this embodiment, a recess 41 capable of accommodating the stage 6 is formed in the basement floor surface 40, and the lowering step includes accommodating the stage 6 in the recess 41. The depth of the recess 41 is approximately equal to the height of the stage 6. This makes it possible to omit the installation of a step adjustment means such as the aforementioned slope 26 on the basement floor surface 40.

[0053] Furthermore, according to this embodiment, the stage 6 has a laminated structure in which multiple layers are stacked in the vertical direction, the lowest layer in this laminated structure includes multiple suspension girders 15 extending parallel to each other at intervals, and the top layer includes multiple support girders 16 extending parallel to each other at intervals, the suspension girders 15 and support girders 16 being perpendicular to each other in a plan view, the suspension girders 15 are suspended and supported by the lifting device 5, and in the heavy equipment delivery process, the heavy equipment 50 is delivered onto the support girders 16. This allows the stage 6 to have a simple configuration consisting of the suspension girders 15 and support girders 16, and ultimately makes it possible to reduce the weight of the stage 6.

[0054] In this embodiment, the lifting device 1 is used to lift and lower the heavy machine 50, but it may also be used to lift and lower a transport vehicle such as a dump truck capable of transporting excavated earth and sand, various materials, and the like.

[0055] The illustrated embodiments are merely illustrative of the present invention, and it goes without saying that the present invention encompasses various improvements and modifications made by those skilled in the art within the scope of the claims, in addition to those directly shown in the described embodiments. The claims at the time of filing were as follows: [Claim 1] A method for lowering a heavy machine from a temporary ground surface consisting of a plurality of covering plates to an underground floor surface using a lifting device installed on the temporary ground surface, The lifting device comprises a portal frame erected on the temporary ground, a lifting device attached to an upper beam of the portal frame, and a stage that can be raised and lowered by the lifting device and can pass up and down through an opening in the temporary ground, The method comprises: a temporary support girder installation process for installing a temporary support girder across the opening; a stage placing step of placing the stage on the temporary support beam; a heavy machine carrying-in process of carrying the heavy machine onto the stage in a state where the heavy machine is placed on the temporary support girder; a ground-raising process of raising the stage with the heavy machine loaded thereon by the lifting device to raise the stage; a temporary support girder removal process of removing the temporary support girder from the opening while the ground is being removed; a lowering process in which, after removing the temporary support girder, the stage with the heavy machine loaded thereon is lowered by the lifting device to pass through the opening and be lowered to the underground floor; Methods for lowering heavy equipment, including: [Claim 2] 2. The method for lowering heavy machinery according to claim 1, wherein in the temporary support girder removal step, the temporary support girder is removed from the opening by sliding it in a longitudinal direction of the temporary support girder. [Claim 3] 3. The method for lowering heavy machinery according to claim 2, wherein the length of the temporary support girder is at least twice the opening width of the opening. [Claim 4] a slope having an inclined surface is installed on the temporary ground; 2. The method for lowering heavy equipment according to claim 1, wherein the heavy equipment carrying-in step includes the heavy equipment self-propelling from the temporary ground surface along the inclined surface of the slope to the stage. [Claim 5] a recess capable of accommodating the stage is formed on the floor of the basement; The method for lowering a heavy machine according to claim 1, wherein the lowering step includes accommodating the stage within the recess. [Claim 6] 6. The method for lowering a heavy machine according to claim 5, wherein the depth of the recess is approximately equal to the height of the stage. [Claim 7] the stage has a stacked structure in which a plurality of layers are stacked in the vertical direction, The bottom layer of the laminated structure includes a plurality of suspension beams extending parallel to each other at intervals, The top layer of the laminated structure includes a plurality of support beams extending parallel to each other at intervals, In plan view, the suspension beam and the support beam are perpendicular to each other, The suspension beam is suspended and supported by the lifting device, 2. The method for lowering heavy equipment according to claim 1, wherein the heavy equipment carrying-in step carries the heavy equipment onto the support girder. [Claim 8] A method for lowering heavy machinery as described in any one of claims 1 to 7, wherein the lifting device comprises a plurality of the portal frames, and a plurality of the lifting devices are attached to the upper beams of each portal frame, and the stage is suspended and supported at multiple points by the lifting devices. [Explanation of symbols]

[0056] 1...lifting device, 2...frame body, 3...girder, 4...height adjustment member, 5...lifting device, 5a...upper hook, 5b...drive unit, 5c...linear member, 5d...suspension hook, 5e...mounting bracket, 5f...suspension tool, 6...stage, 8...front portal frame, 8a...leg, 8b...upper beam, 9...rear portal frame, 9a...leg, 9b...upper beam, 10...upper beam, 11...left side reinforcement, 12...right side reinforcement, 13...rear side reinforcement, 15...suspension beam, 16...receiving beam, 17...horizontal brake base, 18...bracket, 20...temporary support girder, 25...inclined surface, 26...slope, 30...temporary ground, 31...covering plate, 32...underground space, 33...covering girder, 34...opening, 40...underground floor, 41...recess, 50...heavy equipment, 51...lower running body, 52...upper rotating body, 53...base machine, 54...working equipment, 55...crawler track, L0...opening length, L1...length of suspension girder 15, L2...length of support girder 16, L3...length of temporary support girder 20, W0...opening width, W1, W2...narrowest width

Claims

1. A method for lowering a heavy machine from a temporary ground surface consisting of a plurality of covering plates to an underground floor surface using a lifting device installed on the temporary ground surface, The lifting device comprises a portal frame erected on the temporary ground, a lifting device attached to an upper beam of the portal frame, and a stage that can be raised and lowered by the lifting device and can pass up and down through an opening in the temporary ground, The method comprises: a temporary support girder installation process for installing a temporary support girder across the opening; a stage placing step of placing the stage on the temporary support beam; a heavy machine carrying-in process of carrying the heavy machine onto the stage in a state where the heavy machine is placed on the temporary support girder; a ground-raising process of raising the stage with the heavy machine loaded thereon by the lifting device to raise the stage; a temporary support girder removal process of removing the temporary support girder from the opening while the ground is being removed; a lowering process in which, after removing the temporary support girder, the stage with the heavy machine loaded thereon is lowered by the lifting device to pass through the opening and be lowered to the underground floor; Including, In the temporary support girder removal step, the temporary support girder is removed from the opening by sliding it in a longitudinal direction of the temporary support girder, A method for lowering heavy machinery, wherein the length of the temporary support girder is at least twice the opening width of the opening.

2. a slope having an inclined surface is installed on the temporary ground; 2. The method for lowering heavy equipment according to claim 1, wherein the step of carrying in the heavy equipment includes the heavy equipment traveling by itself from the temporary ground surface over the inclined surface of the slope to the stage.

3. a recess capable of accommodating the stage is formed on the floor of the basement; The method for lowering a heavy machine according to claim 1 , wherein the lowering step includes accommodating the stage in the recess.

4. The method for lowering a heavy machine according to claim 3, wherein the depth of the recess is approximately equal to the height of the stage.

5. the stage has a stacked structure in which a plurality of layers are stacked in the vertical direction, The bottom layer of the laminated structure includes a plurality of suspension beams extending parallel to each other at intervals, The top layer of the laminated structure includes a plurality of support beams extending parallel to each other at intervals, In plan view, the suspension beam and the support beam are perpendicular to each other, The suspension beam is suspended and supported by the lifting device, The method for lowering heavy equipment according to claim 1 , wherein the heavy equipment carrying-in step carries the heavy equipment onto the support girder.

6. A method for lowering heavy machinery as described in any one of claims 1 to 5, wherein the lifting device comprises a plurality of the portal frames, and a plurality of the lifting devices are attached to the upper beams of each portal frame, and the stage is suspended and supported at multiple points by the lifting devices.

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