JP7708613B2 - Apparatus and method for recovering surveying targets - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applies. Date of publication on the website: August 2, 2021. Website address: https://confit.atlas.jp/guide/event/jsce2021/participant_login?lang=ja

The present invention relates to a device and method for recovering survey targets.

The New Austrian Tunneling Method (NATM) is a known method for constructing tunnels. In the NATM method, a sprayer is set up near the tunnel face to spray concrete onto the face as a first step, then a work vehicle equipped with an erector for erecting shoring is placed near the face, and arch-shaped steel shoring is erected on the tunnel wall near the face using the erector. Once this is complete, the sprayer is placed back at the face, and the erected tunnel shoring is embedded and the second spraying of concrete is performed.

When erecting steel supports, surveying targets (mirrors, prisms, etc.) attached to the steel supports are sighted with surveying equipment, and the movement of the steel supports is monitored in real time while the steel supports are erected in the designated erection position. Construction aids such as surveying targets must be collected after use.

As a technology for easily attaching and detaching a surveying target to a steel support, for example, a surveying target is known that has a main body with a prism, a magnet that is integrated with the main body and can be fixed to the support, and an operating handle on the magnet for controlling magnetization and demagnetization (see, for example, Patent Document 1). This type of surveying target can be easily attached and detached from the support, improving installation and removal work.

JP 2018-178455 A

In recent years, there has been an increasing demand for technology to avoid manual work at the tunnel face and improve the safety and ease of construction. However, in the past, the removal of survey targets attached to steel supports had to be done manually.

The present invention was made in consideration of the above problems, and its purpose is to provide a technology that makes it possible to retrieve survey targets attached to steel supports without manual labor.

The present invention is a recovery device that recovers a survey target that is magnetically attracted to the flange surface of a steel support, and is equipped with a winding device that is mounted on the hand of an erector device that erects the steel support and is capable of winding up a towing rope that is moored to a predetermined portion of the survey target, and is characterized in that when the survey target is recovered, the winding device winds up the towing rope. Also, when the survey target is recovered, the winding device may wind up the towing rope to cause the survey target to slide over the flange surface.

The present invention is also a method for recovering a survey target used in erecting a steel support, comprising the steps of: mooring a towing rope wound around a winding device mounted on a hand of an erector device for erecting the steel support to a predetermined portion of the survey target magnetically attracted to a flange surface of the steel support; and recovering the survey target by winding up the towing rope with the winding device. In addition, in the step of recovering the survey target, the survey target may be slid on the flange surface to recover the survey target.

The present invention provides a technology that makes it possible to retrieve survey targets attached to steel supports without manual labor.

FIG. 1 is a side view of a tunnel support according to the first embodiment. FIG. 2 is a top view of the work vehicle according to the first embodiment. FIG. 3 is a side view of the work vehicle according to the first embodiment. FIG. 4 is a top view of a hand in the erector device of embodiment 1. FIG. 5 is a schematic diagram of a tunnel support erection system S according to the first embodiment. FIG. 6 is a diagram showing a target according to the first embodiment. FIG. 7 is a diagram showing a manner in which a target is attached to a tunnel support in accordance with the first embodiment. FIG. 8 is an external perspective view of the recovery device according to the first embodiment. FIG. 9 is a diagram illustrating the recovery device according to the first embodiment with the cover removed. FIG. 10 is a diagram showing an example of a remote control in the collection device. FIG. 11 is a diagram showing a state immediately before each survey target is collected by the collection device. FIG. 12 is a diagram showing a state in which the first survey target 9a is being collected by the left first collection device 20 (L1). FIG. 13 is a diagram showing a state in which the second survey target 9b is being collected by the left-side second collection device 20 (L2). FIG. 14 is a diagram showing a state in which automatic collection of all the survey targets has been completed. FIG. 15 is a diagram illustrating the forces acting on the survey target when the survey target is retrieved in a diagonal downward towing pattern. FIG. 16 is a diagram illustrating the forces acting on the survey target when the survey target is retrieved in a diagonal upward towing pattern.

The following describes an embodiment of the present invention with reference to the drawings.

<Embodiment 1>
FIG. 1 is a side view of a tunnel support 10 according to the first embodiment. The tunnel support 10 is applied to the New Austrian Tunneling Method (NATM) and is an arch-shaped steel support erected along the tunnel wall immediately after excavation to prevent the collapse of the ground exposed during tunnel excavation. The tunnel support 10 is installed at regular intervals along the tunnel axis direction. The tunnel support 10 is formed of H-shaped steel having an H-shaped cross section. More specifically, the tunnel support 10 is formed in an arch shape by integrally connecting the top ends (upper ends) of a pair of arc-shaped steel supports 10L and 10R. Hereinafter, the steel support 10L is referred to as the "left side steel support" and the steel support 10R is referred to as the "right side steel support".

The left-side steel support 10L has a first main body 111, a first top joint plate 121, and a first bottom plate 131. The first main body 111 is an H-shaped steel consisting of a web 111a and a pair of upper flanges 111b and lower flanges 111c perpendicular to the web 111a. The first top joint plate 121 is welded to one end of the first main body 111, and the first bottom plate 131 is welded to the other end. The first top joint plate 121 and the first bottom plate 131 are rectangular flat steel plates that extend perpendicular to the H-shaped cross section of the first main body 111. Similarly, the right-side steel support 10R has a second main body 112, a second top joint plate 122, and a second bottom plate 132. The second main body 112 is an H-shaped steel consisting of a web 112a and a pair of upper flanges 112b and lower flanges 112c perpendicular to the web 112a. The first main body 111 of the left steel support 10L and the second main body 112 of the right steel support 10R have a symmetrical arc-shaped longitudinal direction. In addition, a second top joint plate 122 is welded to one end of the second main body 112, and a second bottom plate 132 is welded to the other end. The second top joint plate 122 and the second bottom plate 132 are rectangular steel flat plates and extend perpendicular to the H-shaped cross section of the second main body 112. In this embodiment, the first top joint plate 121 and the second top joint plate 122 have a congruent square plane. As shown in FIG. 1, the left-side steel support 10L and the right-side steel support 10R are connected with the first top joint plate 121 and the second top joint plate 122 butted against each other. The connection structure of the left-side steel support 10L and the right-side steel support 10R may be a structure in which the first top joint plate 121 and the second top joint plate 122 can be fastened with one touch, as disclosed in Patent Document 1 (JP Patent Publication 2018-178455) filed by the present applicant, for example.

The tunnel support 10 described above can be erected by an erector device 100 mounted on a work vehicle 200, which is a heavy construction machine shown in Figures 2 and 3. Figure 2 is a top view of the work vehicle 200 according to the first embodiment. Figure 3 is a side view of the work vehicle 200 according to the first embodiment. The work vehicle 200 is equipped with an erector device 100 and a spraying device 600. The erector device 100 is equipped with a pair of booms 17L, 17R of the same configuration. The pair of booms 17L, 17R can freely extend, tilt, swing, and rotate by the operation of a drive mechanism attached to them. In addition, a pair of hands 18L, 18R of the same configuration are connected to the tip of each boom 17L, 17R. The pair of hands 18L, 18R can rotate and swing freely by operating the drive mechanism attached to them, and can detachably clamp and hold (hold) the left steel support 10L and the right steel support 10R, respectively.

In the following, the boom indicated by reference symbol 17L will be referred to as the "left boom", and the boom indicated by reference symbol 17R will be referred to as the "right boom". Additionally, the hand indicated by reference symbol 18L will be referred to as the "left hand", and the hand indicated by reference symbol 18R will be referred to as the "right hand". However, when there is no need to particularly distinguish between the left boom and the right boom, it may simply be referred to as boom 17. Similarly, when there is no need to particularly distinguish between the left hand and the right hand, it may simply be referred to as hand 18.

The erector device 100 can detachably hold the left steel support 10L with the left hand 18L, and detachably hold the right steel support 10R with the right hand 18R. In this embodiment, the left steel support 10L and the right steel support 10R are a pair of supports formed by dividing the arch-shaped tunnel support 10 into two parts, and after being guided near the tunnel face, they are assembled at the face to form the arch-shaped tunnel support 10.

Fig. 4 is a top view of the hand 18 in the erector device 100. Fig. 4 shows the left hand 18L, but the right hand 18R has a substantially equivalent structure to the left hand 18L. Each hand 18 is provided with a pair of gripping parts 18A, and can grip the steel supports 10R and 10L. In addition, a recovery device 20 is provided at both ends of each hand 18.
The recovery device 20 is a device for recovering the surveying target that is magnetically attracted to the flange surface of the tunnel support 10 (left steel support 10L and right steel support 10R), and the recovery device 20 is used to automatically recover the surveying target, the details of which will be described later. The pair of gripping parts 18A of the hand 18 can grip the lower flanges 111c of the steel supports 10L and 10R with the lower flanges 111c placed on them.

Figure 5 is a schematic diagram of the tunnel support 10 erection system S according to the first embodiment. In the figure, reference numeral 100 denotes an erector device that erects the tunnel support 10, and reference numeral 200 denotes a self-propelled work vehicle (heavy machinery) that is equipped with the erector device 100. Reference numeral 300 denotes an automatic tracking total station that is a distance and angle measuring instrument (surveying instrument) using laser light, reference numeral 400 denotes a total station controller that controls the total station 300, and reference numeral 500 denotes a total station antenna that enables wireless transmission and reception with the total station controller 400. The erector device 100 has a monitor 101 that is a display device mounted on the cockpit, an erector controller 102, an erector antenna 103, an operation panel 104, a keyboard 105, a pointing device 106, and the like. Of course, these specific configurations are examples of the erection system S.

The total station 300 is a surveying instrument that uses laser light to automatically track a surveying target 9, which includes a prism, and measures the position of the target 9 by measuring the distance and angle. The total station 300 is installed at a point in the tunnel whose coordinates are known (point with known coordinates). In this embodiment, the surveying target 9 is attached to the tunnel support 10 (left steel support 10L and right steel support 10R) that is erected at the tunnel face, and the surveying target 9 is automatically tracked as the tunnel support 10 (left steel support 10L and right steel support 10R) moves. Therefore, it is preferable to install the total station 300 at a place where there are no obstacles to the automatic tracking and aiming of such targets. For example, the total station 300 may be installed on the tunnel floor, or a stand may be erected on the ceiling and the total station 300 may be installed on the stand.

The total station controller 400 is configured to include, for example, a portable computer. The total station controller 400 automatically controls various mechanisms of the total station 300 using software built into the computer, and processes the survey data of the total station 300. Furthermore, the total station controller 400 can transmit and receive data via wireless communication with the erector controller 102, and can wirelessly remotely operate various mechanisms of the total station 300 in response to commands from the erector controller 102.

Figure 6 is a diagram showing the target 9 according to the first embodiment. The target 9 has a magnet 92 provided on a holder 91 and a prism 93 attached to the tip side of the holder 91. The holder 91 has a roughly cylindrical shape, and the magnet 92 may be embedded on the bottom surface 91A side. Since the left steel support 10L and the right steel support 10R are made of steel, the target 9 can be detachably attached to the left steel support 10L and the right steel support 10R by the magnetic force of the magnet 92 provided on the holder 91. As shown in Figure 6, the holder 91 is provided with an attachment portion 94 for mooring the tip of the towing rope 26 described later.

FIG. 7 is a diagram showing a manner in which targets are attached to the tunnel support according to the first embodiment. As shown in FIG. 7, the left steel support 10L and the right steel support 10R are symmetrical arc shapes. Here, the left steel support 10L has a first survey target 9a and a second survey target 9b attached to its upper end and lower end, respectively. The right steel support 10R has a third survey target 9c and a fourth survey target 9d attached to its upper end and lower end, respectively. Here, the first survey target 9a to the fourth survey target 9d are collectively referred to as "survey targets 9". Note that there are no particular limitations on the attachment positions and numbers of the "survey targets 9" to the left steel support 10L and the right steel support 10R, and the manner shown in FIG. 7 is one example.

Next, the operation of the erector device 100 when connecting and erecting the left steel support 10L and the right steel support 10R will be described. When connecting and erecting the left steel support 10L and the right steel support 10R, the erector device 100 extends and tilts the left boom 17L and the right boom 17R, and rotates the left hand 18L and the right hand 18R, thereby moving the left steel support 10L and the right steel support 10R perpendicular to the tunnel axis. The operation of each boom 17L, 17R and each hand 18L, 18R in the erector device 100 can be performed by operating the operation panel 104.

The operation of each boom 17L, 17R and each hand 18L, 18R in the erector device 100 can be performed based on the three-dimensional position coordinates of each survey target 9 obtained in real time using the total station 300. For example, the erector controller 102 wirelessly remotely controls the total station 300 via the total station controller 400, automatically tracks each survey target 9 (first target 9a to fourth target 9d), and automatically surveys the coordinates of each survey target 9 in sequence. The total station 300 is installed at a point with known coordinates. In this way, the three-dimensional position coordinates of the first survey target 9a to the fourth survey target 9d can be obtained by irradiating a laser beam from the total station 300 installed at a point with known coordinates to collimate each survey target 9 and measure the distance and angle. The erector controller 102 sets the drive amount for moving the hands 18L and 18R relative to each other based on the survey data of each survey target 9 obtained from the total station 300, and forms an arch-shaped tunnel support 10 by connecting the first top joint plate 121 of the left steel support 10L and the second top joint plate 122 of the right steel support 10R in a butted state as shown in Figure 7.

The details of the control for interconnecting the left-side steel support 10L and the right-side steel support 10R while automatically surveying the coordinates of each survey target 9 (first target 9a to fourth target 9d) in sequence are disclosed in Patent Document 1 (JP 2018-178455 A) filed by the applicant, and therefore will not be described in further detail here. In addition, by making the connection structure of the left-side steel support 10L and the right-side steel support 10R a one-touch joint structure as disclosed in FIG. 9 of Patent Document 1 (JP 2018-178455 A), the left-side steel support 10L and the right-side steel support 10R can be connected in one touch by hand operation of the erector device 100. In addition, the hand operation referred to here includes not only directly operating the hands 18L, 18R by operating the drive mechanism of the hands 18L, 18R, but also indirectly operating the hands 18L, 18R by driving the booms 17L, 17R to which the hands 18L, 18R are attached.

After assembling the tunnel support 10 in an arch shape as described above, the erector device 100 drives the hands 18L and 18R to place the tunnel support 10 at a predetermined erection position near the tunnel face. For example, the erector controller 102 may display the positions of the first survey target 9a to the fourth survey target 9d on the monitor 101 based on survey data including the coordinate positions of each survey target 9 (the first survey target 9a to the fourth survey target 9d) acquired from the total station 300. In addition to the positions of the first survey target 9a to the fourth survey target 9d, the monitor 101 may also display the target positions of the first survey target 9a to the fourth survey target 9d. The operator who operates the erector device 100 can place the tunnel support 10 at the regular erection position by driving the booms 17L and 17R and the hands 18L and 18R while watching the monitor 101.

In this embodiment, at an appropriate timing, for example, when the erection of the tunnel support 10 (left steel support 10L and right steel support 10R) to a specified erection position is completed, each survey target 9 is retrieved from the tunnel support 10 (left steel support 10L and right steel support 10R). Each hand 18L, 18R of the erector device 100 according to this embodiment is equipped with a retrieval device 20 that retrieves each survey target 9 that is magnetically attracted to the flange surface of the tunnel support 10 (left steel support 10L and right steel support 10R), and this retrieval device 20 can be used to automatically retrieve each survey target 9 without relying on human labor. Details of the survey target retrieval device and the retrieval method are described below.

The recovery device 20 mounted on each hand 18L, 18R will be described with reference to Figures 8 and 9. Figure 8 is an external perspective view of the recovery device 20 according to the first embodiment. Figure 9 is a view illustrating the recovery device 20 according to the first embodiment with the cover removed. The recovery device 20 includes a base plate 21 attached to the end of each hand 18L, 18R, a winch 22 (winding device), a battery 23 (power source), a control box 24, and a cover 25, which are installed on the base plate 21. The base plate 21 has screw holes for mounting the winch 22, battery 23, and control box 24 directly or via a bracket, etc., and the winch 22, battery 23, and control box 24 are fixed to a predetermined position on the base plate 21 using screws, brackets, etc.

The winch 22 is, for example, an electric winch, and the towing rope 26 is wound around the drum part 22A that is rotated in the forward and reverse directions. The winch 22 is driven by receiving power from the battery 23, and the drive is controlled by a control unit including a control board and the like stored in the control box 24. For example, the drum part 22A of the winch 22 is rotated in the forward direction to pull out the towing rope 26, and the drum part 22A is rotated in the reverse direction to wind up the towing rope 26. The recovery device 20 may include a remote controller (remote control) for remotely operating the drive of the winch 22. FIG. 10 is a diagram showing an example of a remote control in the recovery device 20. The remote control 30 has, for example, a pull-out button 31 and a wind-up button 32. The remote control 30 can communicate with the control unit in the control box 24, and the winch 22 can be driven by an operator operating the remote control 30. For example, while the worker continues to press the pull button 31 on the remote control 30, the drum portion 22A of the winch 22 is rotated in the forward direction to pull out the towing rope 26 at a constant speed, and while the worker continues to press the winding button 32, the drum portion 22A of the winch 22 is rotated in the reverse direction to wind up the towing rope 26 at a constant speed. Additionally, the remote control 30 may have an on-off button.

The base plate 21 of the recovery device 20 is provided with a guide member 27 for guiding the pulling out and winding of the towing rope 26, and the towing rope 26 is passed through a guide hole 27A of the guide member 27. A loop 26A for attaching a mounting bracket 28 such as a carabiner is formed at the end of the towing rope 26. A mounting bracket 28 such as a carabiner is attached to the loop 26A of the towing rope 26, and the loop 26A of the towing rope 26 can be moored to a mounting part 94 provided on the holder 91 of the survey target 9 via the mounting bracket 28. The cover 25 of the recovery device 20 is provided with a cutout portion 25A for exposing the guide member 27 to the outside, and is configured so that the guide hole 27A of the guide member 27 is not covered by the cover 25 even when the cover 25 is attached to the base plate 21.

In this embodiment, the towing rope 26 is formed of, for example, a wire rope, but there is no particular limitation on the material as long as it can tow the survey target 9 along the flange surface when retrieving the survey target 9. For example, the towing rope 26 may be formed of synthetic fibers such as nylon, polyester, polypropylene, polyethylene, vinylon, etc., or may be formed of natural fibers such as hemp, cotton, etc.

Next, a method for automatically collecting each survey target 9 using the collection device 20 will be described with reference to Figures 11 to 14. Figure 11 is a diagram showing the state immediately before collecting each survey target 9 using the collection device 20. As an example, Figure 11 shows a state in which a tunnel support 10 assembled in an arch shape is installed in a specified erection position. Figure 11 shows a left hand 18L that grasps the left steel support 10L, and a right hand 18R that grasps the right steel support 10R. For convenience, the booms 17L and 17R are omitted from the illustration.

Of the set of recovery devices 20 mounted on the left hand 18L, the recovery device for recovering the first survey target 9a installed on the top end (upper end) side of the left steel support 10L is called the "left first recovery device 20 (L1)," and the recovery device for recovering the second survey target 9b installed on the lower end side of the left steel support 10L is called the "left second recovery device 20 (L2)." Similarly, of the set of recovery devices 20 mounted on the right hand 18R, the recovery device for recovering the third survey target 9c installed on the top end (upper end) side of the right steel support 10R is called the "right first recovery device 20 (R1)," and the recovery device for recovering the fourth survey target 9d installed on the lower end side of the right steel support 10R is called the "right second recovery device 20 (R2)." Note that the above recovery devices 20 (L1), 20 (L2), 20 (R1), and 20 (R2) are shown to be distinct from one another in relation to the survey target 9 that they are to recover, but their structures and functions are essentially equivalent.

In FIG. 11, the towing rope 26 of the first left recovery device 20 (L1) is connected to the first survey target 9a by mooring the tip side mounting bracket 28 to the mounting part 94 of the first survey target 9a. The towing rope 26 of the second left recovery device 20 (L2) is connected to the second survey target 9b by mooring the tip side mounting bracket 28 to the mounting part 94 of the second survey target 9b. The towing rope 26 of the first right recovery device 20 (R1) is connected to the third survey target 9c by mooring the tip side mounting bracket 28 to the mounting part 94 of the third survey target 9c. The towing rope 26 of the second right recovery device 20 (L2) is connected to the fourth survey target 9d by mooring the tip side mounting bracket 28 to the mounting part 94 of the fourth survey target 9d. As shown in FIG. 11, the towing rope 26 of each recovery device 20 is in a slack state so that a large tension is not applied to the connected survey target 9. In this embodiment, the lower flange 112c of the left steel support 10L has marks in advance with paint or the like at the specified positions Ps1 and Ps2 where the first survey target 9a and the second survey target 9b should be attached, so that the first survey target 9a and the second survey target 9b are attached to the specified positions Ps1 and Ps2, respectively. Similarly, the lower flange 112c of the right steel support 10R has marks in advance with paint or the like at the specified positions Ps3 and Ps4 where the third survey target 9c and the fourth survey target 9d should be attached, so that the third survey target 9c and the fourth survey target 9d are attached to the specified positions Ps3 and Ps4, respectively.

Here, before connecting and erecting the left-side steel support 10L and the right-side steel support 10R, the towing rope 26 may be pulled out sufficiently from each recovery device 20 and connected in a slack state to the mounting part 94 (predetermined part) of each survey target 9. By doing so, there is no need to moor the tip of the towing rope 26 to the mounting part 94 of each survey target 9 near the tunnel face, which further improves the safety of the work.

The remote control 30 shown in FIG. 10 may be provided for each recovery device 20. Each survey target 9 is recovered by operating the winding button 32 on the remote control 30 corresponding to each recovery device 20 and winding the towing rope 26 with the winch 22 of each recovery device 20. At that time, each survey target 9 may be recovered by sliding it on the flange surface of the lower flanges 112c, 122c.

Figure 12 shows, as an example, a situation in which the first survey target 9a is being collected by the left first collection device 20 (L1). Figure 13 shows, as an example, a situation in which the second survey target 9b is being collected by the left second collection device 20 (L2). In Figure 13, the collection of the first survey target 9a by the left first collection device 20 (L1) is complete. The automatic collection of the third survey target 9c and the fourth survey target 9d using the right first collection device 20 (R1) and the right second collection device 20 (R2) can also be performed by sliding them on the flange surface of the lower flange 112c of the right steel support 10R, as with the first survey target 9a and the second survey target 9b. Figure 14 shows a state in which automatic collection of all survey targets 9 has been completed.

As described above, according to the survey target 9 recovery device 20 and the recovery method using the same in this embodiment, the survey target 9 can be recovered automatically. Therefore, it is not necessary to recover each survey target 9 manually using the man cage of the erector device 100, etc. As a result, it is possible to improve the efficiency and safety of tunnel construction compared to the conventional method.

The process after the recovery work of each survey target 9 is completed is not particularly limited, but for example, the tunnel support 10 (left steel support 10L and right steel support 10R) may be held by each hand 18L, 18R of the erector device 100, and secondary shotcrete may be sprayed from the spraying device 600 to temporarily fix the tunnel support 10 to the tunnel wall surface. In this case, the tunnel support 10 may be temporarily fixed to the tunnel wall surface by spraying secondary shotcrete against the legs of the left steel support 10L and right steel support 10R and the surrounding tunnel wall surface (surface of the primary shotcrete), and then the grip of the tunnel support 10 by the hands 18L, 18R of the erector device 100 may be released. Next, secondary shotcrete may be sprayed between the new tunnel support 10 and the existing tunnel support 10 that are adjacent in the axial direction of the tunnel (new section), and the entire longitudinal area of the new tunnel support 10 may be embedded in the secondary shotcrete, thereby fixing the new tunnel support 10 to the tunnel wall surface (surface of the primary shotcrete).

<Conditions for survey targets to slide without falling when retrieving them>
Next, when the survey target 9 is towed by the towing rope 26 of the recovery device 20, the conditions for sliding the survey target 9 along the lower flanges 112c, 122c of the left-side steel support 10L and the right-side steel support 10R without the survey target 9 falling from the lower flanges 112c, 122c will be considered.

In the following, a pattern in which the survey target 9 is pulled diagonally downward by the towing rope 26 of the recovery device 20 arranged at a lower position than the survey target 9 (hereinafter referred to as the "diagonally downward towing pattern") and a pattern in which the survey target 9 is pulled diagonally upward by the towing rope 26 of the recovery device 20 arranged at a higher position than the survey target 9 (hereinafter referred to as the "diagonally upward towing pattern") will be described separately. The mode in which the first survey target 9a and the third survey target 9c are respectively recovered by the above-mentioned first left recovery device 20 (L1) and first right recovery device 20 (R1) corresponds to the diagonally downward towing pattern. On the other hand, the mode in which the second survey target 9b and the fourth survey target 9d are respectively recovered by the above-mentioned second left recovery device 20 (L2) and second right recovery device 20 (R2) corresponds to the diagonally downward towing pattern.

Figure 15 is a diagram explaining the forces acting on the survey target 9 when the survey target 9 is retrieved in a diagonally downward towing pattern. That is, Figure 15 shows the forces acting on the survey targets 9a and 9c when the first survey target 9a adsorbed to the flange surface F1 of the lower flange 112c of the left steel support 10L (first main body part 111) is retrieved by the left first retrieval device 20 (L1), or when the third survey target 9c adsorbed to the flange surface F1 of the lower flange 112c of the right steel support 10R (first main body part 121) is retrieved by the right first retrieval device 20 (R1). Therefore, the survey target 9 in the explanation of Figure 15 specifically refers to the survey targets 9a and 9c.

Here, the tangent direction of the flange surface F1 at the position where the survey target 9 is in contact with the flange surface F1 of the lower flanges 112c, 122c is defined as the x direction, and the direction on a plane including the x direction and the vertical direction and perpendicular to the x direction is defined as the y direction. The positive direction of the x direction is the direction from the survey target 9 toward the recovery device 20 (20(L1), 20(R1)) that recovers the survey target 9. The positive direction of the y direction is the direction from the flange surface F1 of the lower flanges 112c, 122c toward the survey target 9. The dimension of the part of the survey target 9 in the x direction that is in contact with the flange surface F1 is defined as length a. The distance in the y direction from the mounting portion 94 of the survey target 9 to the flange surface F1 is defined as length b. Since the bottom surface 91A of the survey target 9 is attached to the flange surface F1, the length b is substantially equal to the height dimension from the mounting portion 94 to the bottom surface 91A of the survey target 9. The distance in the y direction from the center of gravity of the survey target 9 to the flange surface F1 is defined as the length c. The mass of the survey target 9 is defined as m, and the gravitational acceleration is defined as g. The normal force that the survey target 9 receives from the flange surface F1 is defined as N. The magnetic force acting between the survey target 9 and the flange surface F1 is defined as S. The tension applied to the towing rope 26 connected to the mounting portion 94 of the survey target 9 is defined as T. The angle between the horizontal direction and the x direction is defined as α, and the angle between the horizontal direction and the direction of the towing rope 26 is defined as θ. The angles α and θ are positive in the counterclockwise direction from the horizontal direction.

Here, if the magnitude of the normal force N is positive, the survey target 9 maintains its adherence to the flange surface F1 and does not fall. Since the survey target 9 adhered to the flange surface F1 does not move in the y direction, the force balance equation in the y direction of the survey target 9 is given by the following formula 1 and its converted formula 2.
S=mgcosα+Tsin(θ-α)+N...(Formula 1)
N=S-mgcosα-Tsin(θ-α)...(Formula 2)
Here, as described above, if the normal force N is a positive value, the attracted state of the survey target 9 is maintained. Therefore, the conditional formula A for preventing the survey target 9 from falling is obtained as follows.
S>mgcosα+Tsin(θ-α)...(Conditional expression A)

Next, the survey target 9 starts to slide on the flange surface F1 when the resultant force acting in the x direction becomes greater than the maximum static friction force. Therefore, the condition under which the stationary survey target 9 starts to slide along the flange surface F1 can be expressed by Equation 3-1. Conditional Equation B is derived by further transforming Equation 3-2, which is a transformation of Equation 3-1.
μN<mgsinα+Tcos(θ-α)...(Formula 3-1)
μ(S-mgcosα-Tsin(θ-α))<mgsinα+Tcos(θ-α)...(Formula 3-2)
S<(mgsinα+Tcos(θ-α))/μ+mgcosα+Tsin(θ-α) (conditional expression B)
Here, μ is the maximum static friction coefficient between the flange surface F1 and the survey target 9 (9a, 9c).

Next, the condition for the stationary survey target 9 to continue to slide along the flange surface F1 is satisfied when the resultant force in the x direction is greater than the kinetic friction force. Therefore, the condition for the survey target 9 to continue to slide along the flange surface F1 can be expressed by the following formula 4-1. Conditional formula C is derived by further transforming formula 4-2, which is a transformation of formula 4-1.
μ′N<mgsinα+Tcos(θ−α)...(Formula 4-1)
μ'(S-mgcosα-Tsin(θ-α))<mgsinα+Tcos(θ-α)...(Formula 4-1)
S<(mgsinα+Tcos(θ-α))/μ′+mgcosα+Tsin(θ-α)...(Conditional expression C)
Here, μ′ is the dynamic friction coefficient between the flange surface F1 and the survey target 9. Since μ′ is smaller than μ, when conditional formula B is satisfied, conditional formula C is also satisfied at the same time.

Furthermore, when the clockwise moment acting on the survey target 9 is smaller than the counterclockwise moment when the survey target 9 is towed, the survey target 9 will not fall over. The clockwise moment acting on the survey target 9 is expressed by Equation 5.
cmgcosα+(a/2)mgsinα+aTsin(θ-α)...(Formula 5)
On the other hand, the counterclockwise moment acting on the survey target 9 is expressed by the following formula 6-1.
(a/2)×S+bTcos(θ-α)...(Formula 6-1)
From the above, the condition for the survey target 9 not toppling over when towed is met when the following formula 6-2 is satisfied, and conditional formula D is derived by converting formula 6-2.
cmgcosα+(a/2)mgsinα+aTsin(θ-α)<(a/2)×S+bTcos(θ-α)...(Formula 6-2)
S<mg((2c/a)cosα+sinα)+T(2sin(θ-α)-(2b/a)cos(θ-α))...(Conditional expression D)

Next, the "diagonal upward towing pattern" will be explained. FIG. 16 is a diagram for explaining the forces acting on the survey target 9 when the survey target 9 is retrieved using the diagonal upward towing pattern. That is, FIG. 16 shows the forces acting on the survey targets 9b and 9d when the second survey target 9b adsorbed to the flange surface F1 of the lower flange 112c of the left steel support 10L (first main body 111) is retrieved by the left second retrieval device 20 (L2), or when the fourth survey target 9c adsorbed to the flange surface F1 of the lower flange 112c of the right steel support 10R (first main body 121) is retrieved by the right second retrieval device 20 (R2). Therefore, the survey target 9 in the explanation of FIG. 16 specifically refers to the survey targets 9b and 9d.

In FIG. 16, the reference axis directions such as the x direction and y direction, their positive and negative directions, normal force N, mass m, gravitational acceleration g, magnetic force S, etc. are the same as those explained in FIG. 15. As explained in FIG. 15, the angles α and θ are set with the counterclockwise direction from the horizontal direction being positive, so in the "diagonal upward traction pattern" shown in FIG. 16, the angles α and θ will mainly take negative values, but it does not matter whether the angles α and θ are positive or negative.

16, if the normal force N is positive, the survey target 9 is maintained in an attracted state to the flange surface F1 and does not fall. Therefore, in the case of the diagonal upward pulling pattern, similarly to the case of the diagonal downward pulling pattern described above, when the conditional expression 1 is satisfied, the survey target 9 is maintained in an attracted state to the flange surface F1 and is prevented from falling.

For the diagonal upward towing pattern, the conditions under which the stationary survey target 9 starts to slide along the flange surface F1 and the conditions under which the survey target 9 continues to slide along the flange surface F1 can be expressed by conditional formula (2) and conditional formula (3) similar to those for the diagonal downward towing pattern. For the diagonal upward towing pattern, the conditions under which the survey target 9 does not tip over when towed can be expressed by conditional formula (4) similar to those for the diagonal downward towing pattern.

As described above, in both the diagonally downward pulling pattern and the diagonally upward pulling pattern, by satisfying conditional expressions 1, 2, and 4, when the survey target 9 is retrieved by the retrieval device 20, the survey target 9 can continue to slide along the flange surface F1 without tipping over or falling. This allows the survey target 9 to be smoothly pulled and retrieved along the flange surface F1.

The above describes an embodiment of a recovery device and a recovery method for recovering survey targets, but each configuration and combination thereof in the embodiment is merely an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate without departing from the spirit of the present invention. Furthermore, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification.

9: Survey target 10: Tunnel support 18: Hand 18A: Grip 20: Recovery device 22: Winch 26: Towing rope 27: Guide member 91: Holder 92: Magnet 93: Prism 94: Mounting part 100: Erector device

Claims (2)

A recovery device for recovering a survey target that is attracted to a flange surface of a steel support by the magnetic force of a magnet provided in a holder ,
A winding device is provided which is mounted on the hand of the erector device for erecting the steel support and can wind up the towing rope moored at a predetermined portion of the survey target,
When the survey target is retrieved, the towing rope is wound up by the winding device , so that the bottom surface of the holder in the survey target can be slid on the flange surface while being adhered to the flange surface.
A survey target recovery device. A method for recovering a survey target used in erecting a steel support structure, comprising:
A process of mooring a towing rope wound around a winding device mounted on a hand of an erector device that erects the steel support to a predetermined portion of the survey target that is attracted to the flange surface of the steel support by the magnetic force of a magnet provided in a holder ;
Retrieving the survey target by winding up the tow rope with the winding device;
Including,
In the step of recovering the survey target, the bottom surface of the holder of the survey target can be slid on the flange surface while being adhered to the flange surface.
How to recover survey targets.