Steel pipe pile connection method

Abstract

PURPOSE: To provide a joint method of steel pipe piles allowing a welding bogie to travel in a stable state and allowing homogeneous weldment quality to be achieved.CONSTITUTION: A joint method for welding a joint line between a first steel pipe pile and a second steel pipe pile using a weldment device to move in a circumferential direction along the outer periphery of the steel pipe piles, comprises steps of: attaching a doughnut-shaped travel guide plate in a horizontal state so as to surround the outer periphery of a part near an upper end of the first steel pipe pile at a position near a lower part of the joint line over the periphery; and making a weldment bogie of a specific structure travel on the outer periphery in the circumferential direction while magnetically attached on the outer periphery surface of the second steel pipe pile at a position higher than the joint line, as well as making the weldment bogie travel for weldment while checking its position by bringing a roller of a guide roller part into contact with an upper surface of the travel guide plate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for connecting steel pipe piles, and more particularly to a method for welding joints using a welding carriage that moves circumferentially around the outer periphery of a steel pipe pile when extending a vertical pile piping. [Background technology]

[0002] When burying vertical pile piping, multiple steel pipes are prepared on site and then joined vertically by welding as construction progresses. Steel pipe piles are welded together by butting the upper end of the first steel pipe pile, which serves as the lower pile, against the lower end of the second steel pipe pile, which serves as the upper pile, and then circumferentially welding the joint at the butted point. During this circumferential welding, a running rail is attached to the outer periphery of the steel pipe pile, and the welding joint is welded while a welding carriage travels on this running rail (see, for example, Patent Documents 1 to 3, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-281483 [Patent Document 2] JP 2005-334916 A [Patent Document 3] Patent No. 4040076 Summary of the Invention [Problem to be solved by the invention]

[0004] The technologies of Patent Documents 1 to 3 are configured such that a circular running rail is attached to the outer periphery of a steel pipe, spaced apart from the outer surface, and a welding carriage is run on this running rail while welding the seam using a welding torch mounted on the welding carriage.

[0005] However, in the technologies of Patent Documents 1 to 3, the weight of the welding carriage and the load during travel are all applied to the rail, so not only is a high-strength running rail configuration required to withstand the weight and load of the welding carriage while it is traveling, but the running rail also needs to be attached strongly to the steel pipe pile. If even one of these strength conditions is insufficient, the running trajectory of the welding carriage will become unstable and will wobble, making the welding of the joint by the welding torch unstable, which not only results in unstable weld quality but can also lead to poor welding.

[0006] Therefore, an object of the present invention is to provide a method for connecting steel pipe piles that allows a welding carriage to travel in a stable state and that can obtain uniform welding quality. [Means for solving the problem]

[0007] The present invention, which solves the above problems, has the following configuration.

[0008] 1. A method for connecting steel pipe piles in which a joint between a first steel pipe pile and a second steel pipe pile connected on top of the first steel pipe pile is welded using a welding device that moves circumferentially around the outer periphery of the steel pipe pile, A donut-shaped running guide plate is attached horizontally around the entire periphery of the first steel pipe pile near the upper end thereof, which is located near the lower portion of the joint; A welding carriage having the following configuration is magnetically attracted to the outer peripheral surface of the second steel pipe pile above the joint while traveling in a circumferential direction around the outer peripheral surface, and welding is performed by traveling the welding carriage while confirming the position by abutting the rollers of the guide roller portion on the upper surface of the traveling guide plate. A method for connecting steel pipe piles, characterized by: "Welding trolley configuration" The structure comprises a plurality of wheel sections formed mainly from magnet bodies that run and rotate while being magnetically attracted to the outer circumferential surface of the second steel pipe pile by the magnet bodies, a drive mechanism that runs and rotates the wheel sections, a welding torch section that welds the joints at the welding points, and a guide roller section that moves freely and abuts the running guide plate to follow the weld line.

[0009] 2. A method for connecting steel pipe piles as described in 1 above, characterized in that two rollers are provided, and these two rollers abut against the running guide plate at two points spaced apart in the circumferential direction, and welding is performed by a welding torch at a position between the two points where the rollers abut.

[0010] 3. A method for connecting steel pipe piles as described in 1 or 2 above, characterized in that the contact position of the roller with the running guide plate is close to the outer surface of the steel pipe pile, which is near the inner circumference of the donut-shaped running guide plate.

[0011] 4. A method for connecting steel pipe piles described in any one of 1 to 3 above, characterized in that the welding carriage has an outer circumferential guide roller portion separate from the guide roller portion, and the outer circumferential roller of the outer circumferential guide roller portion abuts against the donut-shaped outer circumferential position of the running guide plate and runs freely.

[0012] 5. A method for connecting steel pipe piles according to any one of 1 to 4 above, characterized in that the travel guide plate is a pair of half-doughnut shaped plates.

[0013] 6. The donut-shaped guide plate is mounted in the following way: The L-shaped vertical line portions of each of the multiple inverted L-shaped members are attached and fixed at any intervals to a bendable long strip-like plate, and the long strip-like plate is wrapped around and fixed to the outer circumferential surface of the first steel pipe pile so that the L-shaped horizontal line portions of each of the multiple inverted L-shaped members face outward and maintain horizontality. After that, a donut-shaped traveling guide plate is placed and fixed on each of the L-shaped horizontal line portions of the multiple inverted L-shaped members. 6. The method for connecting steel pipe piles according to any one of 1 to 5 above,

[0014] 7. A method for connecting steel pipe piles as described in 6 above, characterized in that a long strip plate is wrapped around the outer peripheral surface of the first steel pipe pile, and then a tightening member is wrapped around the outer peripheral surface of the long strip plate or the outside of the L-shaped vertical line portions of multiple inverted L-shaped members to tighten and fix them.

[0015] 8. The donut-shaped guide plate is mounted as follows: A plurality of L-shaped steel members are fixed to the outer peripheral surface of the first steel pipe pile so that each L-shaped horizontal wire portion faces outward and maintains horizontality, and a donut-shaped traveling guide plate is placed and fixed on the L-shaped horizontal wire portion. 8. The method for connecting a steel pipe pile according to any one of 1 to 7 above,

[0016] In this specification, the term "first steel pipe pile" refers to the lower steel pipe pile of two connected steel pipe piles, and the upper steel pipe pile whose lower end is connected to the upper end of the lower steel pipe pile is referred to as the "second steel pipe pile." Therefore, when a next steel pipe pile is connected to the top of the second steel pipe pile after these two piles have been connected, the previous second steel pipe pile will be referred to as the "first steel pipe pile" because it will be the lower pile, and the next steel pipe pile will be referred to as the "second steel pipe pile" because it will be the upper pile. [Effects of the Invention]

[0017] According to the invention set forth in claim 1, it is possible to provide a method for connecting steel pipe piles that enables a welding carriage to travel in a stable state and that can obtain uniform welding quality.

[0018] In particular, the welding carriage is configured to travel while being magnetically attracted to the outer surface of the vertical pile piping by the magnetic attraction of the wheel parts formed from a magnetic body, so the weight of the welding carriage and the load during travel are not applied to the travel guide plate, and therefore high-strength travel rails and mounting configurations as in the above-mentioned Patent Documents 1 to 3 are not required. In addition, the welding carriage is configured to follow the weld line by having the rollers of the guide roller section abut against the running guide plate attached to the outer surface of the steel pipe pile and allowing it to run freely, so the welding carriage can run accurately while checking its position, resulting in accurate and uniform welding quality in a stable state. Furthermore, since the rollers of the guide roller section, the traveling guide plate against which the rollers abut, the seam to be welded, and the welding torch section that welds the seam are all positioned close to each other, the deviation in the positional accuracy of each can be significantly reduced compared to a configuration in which these positions are far apart. Furthermore, since the traveling guide plate is not subjected to the weight of the welding carriage or load during travel, the configuration of the traveling guide plate and the configuration for attaching it to the steel pipe pile can be simple, and materials and scraps that are easily available and procured at construction sites, etc. can be used at low cost. Furthermore, since the configuration of the running guide plate and the configuration for attaching it to the steel pipe pile are simple and sufficient, it becomes easy to relocate the running guide plate when the welding of the joint between the first steel pipe pile and the second steel pipe pile is completed and the next steel pipe pile is connected to the top of the second steel pipe pile.

[0019] According to the invention shown in claim 2, the rollers of the guide roller section abut at two points on the traveling guide plate, and welding is performed between these two points. This configuration keeps the traveling trajectory of the welding carriage stable and prevents it from shaking, thereby stabilizing the welding of the joint by the welding torch section and achieving stable welding quality.

[0020] According to the invention set forth in claim 3, the rollers of the guide roller section are configured to abut near the inner circumference of the traveling guide plate, so that they are close to the seam to be welded, thereby providing high positional accuracy of the welding carriage relative to the seam.

[0021] According to the invention described in claim 4, the traveling position of the welding carriage can be checked from the outer circumferential position of the traveling guide plate, allowing for more accurate traveling, thereby achieving more stable, accurate and uniform welding quality. Furthermore, even if there is a risk of the welding carriage coming off due to a decrease in the magnetic force of the magnet, vibration, or other factors that weaken the magnetic attraction force of the welding carriage, the outer peripheral rollers support the welding carriage from the outer peripheral position of the traveling guide plate, so that coming off can be prevented or suppressed.

[0022] According to the invention set forth in claim 5, the traveling guide plates are in the shape of a pair of half donuts, and therefore can be formed using plate material that is easily available or procured at construction sites, etc., making it low-cost and easy to manufacture.

[0023] According to the invention set forth in claim 6, the running guide plate is formed using materials and scraps that can be easily obtained or procured at construction sites, such as an upside-down L-shaped member and a bendable long strip plate, and therefore can be manufactured easily and at low cost.

[0024] According to the invention set forth in claim 7, the attachment of the travel guide plate to the steel pipe pile can be carried out using a fastening member such as a chain block that can be easily obtained or procured at construction sites, etc., making it low-cost and easy.

[0025] According to the invention set forth in claim 8, the traveling guide plate is formed using L-shaped steel material, which is a material or scrap that can be easily obtained or procured at construction sites, etc., and can therefore be manufactured easily and at low cost. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic front view showing an embodiment of a method for connecting steel pipe piles according to the present invention; [Figure 2] Schematic left side view of Figure 1 [Figure 3] FIG. 1 is a schematic perspective view illustrating the structure of a traveling guide plate used in the present invention. [Figure 4] Schematic plan view (part 1) illustrating an example of the installation configuration of the running guide plate on the steel pipe pile [Figure 5] Schematic plan view (part 2) explaining an example of the installation configuration of the running guide plate on the steel pipe pile [Figure 6] Schematic plan view (part 3) explaining an example of the installation configuration of the guide plate on the steel pipe pile [Figure 7] Schematic plan view (part 4) explaining an example of the installation configuration of the running guide plate on the steel pipe pile [Figure 8] Schematic front view of Figure 7 [Figure 9]Schematic side view illustrating another example of the mounting configuration of the travel guide plate to the steel pipe pile [Figure 10] FIG. 10 is a schematic left side view showing another embodiment of the method for connecting steel pipe piles according to the present invention using a welding carriage with another configuration. DETAILED DESCRIPTION OF THE INVENTION

[0027] Next, the method for connecting steel pipe piles of the present invention will be described in detail with reference to the accompanying drawings.

[0028] The method for connecting steel pipe piles of the present invention involves, when carrying out burial work while joining multiple steel pipes by welding in vertical pile piping installation work or the like, butting the upper end of a first steel pipe pile (which will serve as the lower pile) with the lower end of a second steel pipe pile (which will serve as the upper pile), and then circumferentially welding the joint at the butted portion. This circumferential welding can be performed using various welding devices, but in the present invention, the welding is performed by running a welding carriage circumferentially around the outer periphery of the steel pipe pile near the joint.

[0029] As a specific configuration of the connection method for steel pipe piles of the present invention, as shown in Figures 1 and 2, In a configuration in which a joint 3 between a first steel pipe pile 1 and a second steel pipe pile 2 connected on top of the first steel pipe pile 1 is welded by a welding carriage 4, A donut-shaped running guide plate 5 is attached horizontally around the entire periphery of the first steel pipe pile 1 near the upper end thereof, which is located below the joint 3. A welding carriage 4 having the following configuration is magnetically attracted to the outer peripheral surface of the second steel pipe pile 2 above the joint 3 while traveling in a circumferential direction around the outer peripheral surface, and the welding carriage is traveled while the rollers of the guide roller portion are brought into contact with the upper surface of the traveling guide plate 5 to confirm the position, thereby performing welding. The main components are:

[0030] The welding cart 4 is configured to include a plurality of wheel sections 41 formed mainly from magnets that run and rotate while being magnetically attracted to the outer circumferential surface of the second steel pipe pile 2 by the magnets, a drive mechanism (not shown) that runs and rotates the wheel sections 41, a welding torch section 42 that welds the joint 3, which is the welding point, and a guide roller section 43 that follows the weld line by abutting a freely running roller 43A against the traveling guide plate 5, and when welding the joint 3, it runs in a circumferential direction around the outer circumferential surface of the second steel pipe pile 2.

[0031] The welding carriage 4 is preferably used, for example, when welding the joints 3 of steel pipe piles 1 and 2, which are generally about 90 cm in diameter, and specifically has a weight of about 5 kg, a tractive force of about 11 kg, body dimensions of about 250 mm in width, about 200 mm in length, and about 230 mm in height, and a traveling speed of about 100 to 550 mm / min. Note that various power cords and the like connected to the welding carriage 4 are not shown in the drawings of this embodiment.

[0032] Furthermore, since the wheel portion 41 is mainly formed from a magnet, and the steel pipe piles 1 and 2 are generally formed from ferrous steel plates, it is preferable that the number of wheels is six in consideration of running stability, etc., and that the running surfaces of these six wheels are covered with a rubber-based material. In the case of the welding carriage 4 of this embodiment having the above-described configuration, it is preferable that the adhesive force of the magnetic body of the wheel section 41 for magnetically adsorbing to the steel pipe pile 2 is approximately 25 to 30 kg in total for the multiple wheel sections 41 (six in this embodiment).

[0033] It is preferable that welding torch unit 42 be configured to be attached to the main body of welding carriage 4 via an arm or the like so that the angle (horizontal angle, forward angle / reverse angle, etc.) and distance relative to seam 3, which is the welding point, can be adjusted. These adjustments are made by adjusting welding torch unit 42 according to the distance between the magnetic attraction traveling position of welding carriage 4 to steel pipe pile 2 and the position of seam 3, so that welding torch unit 43 can be maintained in an appropriate and accurate position relative to seam 3, thereby achieving stable welding quality.

[0034] Furthermore, as the welding configuration using the welding torch portion 42, any known and commonly used welding method can be used without any particular restrictions as a welding means used in connecting steel pipe piles of this type, and among these, general arc welding can be preferably used.

[0035] Preferably, guide roller unit 43 is provided with two rollers 43A, and these two rollers 43A contact traveling guide plate 5 at two circumferentially spaced locations, and welding is performed by welding torch unit 42 at a position between the two locations where rollers 43A contact. With this configuration, rollers 43A of guide roller unit 43 contact traveling guide plate 5 at two locations, and welding is performed between these two locations. This configuration stabilizes the traveling trajectory of welding carriage 4 without any deviation, thereby stabilizing welding of joint 3 by welding torch unit 42 and achieving stable welding quality.

[0036] Furthermore, the contact position of the roller 43A of the guide roller portion 43 against the traveling guide plate 5 is preferably a position close to the outer circumferential surface of the first steel pipe pile 1, which is a position near the inner periphery of the doughnut-shaped traveling guide plate 5. The specific distance from the outer circumferential surface of the first steel pipe pile 1 to the contact position of the roller 43A is preferably about 3 to 105 mm, and more preferably about 5 to 20 mm.

[0037] Furthermore, the guide roller unit 43 is preferably configured to be attached to the main body of the welding carriage 4 via an arm unit or the like so that the extension of the guide roller unit 43 and the distance from the outer circumferential surface of the steel pipe pile 2 can be adjusted according to the distance between the magnetic attraction traveling position of the welding carriage 4 and the steel pipe pile 2, the attachment position of the traveling guide plate 5, etc. With this configuration, the roller 43A of the guide roller unit 43 can be brought into contact with the upper surface of the traveling guide plate 5 in an appropriate and accurate state.

[0038] As the welding carriage 4 having the above configuration, for example, a commercially available welding carriage WEL-HANDY COMPACT manufactured by Koike Oxygen Industry Co., Ltd. can be used as is or after partial modification. In this embodiment, the number of wheels of the wheel section 41 formed mainly from a magnetic body is increased by two from four to a total of six, thereby increasing the magnetic attraction force by 1.5 times, and by increasing the number of magnetic attraction points from four to six, the risk of wheels coming off is also reduced. Furthermore, the two additional wheel sections 41 are configured to be installed at positions further away from the joint 3 than the two wheel sections 41 furthest from the joint 3 of the original four wheel sections 41, so that the increased magnetic attraction force is exerted at positions further away from the joint 3, which becomes hot due to welding, thereby significantly preventing a decrease in magnetic force due to the heat effect during welding. Therefore, the welding cart 4 can be run in a more stable state while being magnetically attracted to the outer circumferential surface of the steel pipe pile 2.

[0039] Next, the traveling guide plate 5 that the rollers 43A of the guide roller portion 43 of the welding carriage 4 contact while traveling freely and follows the weld line will be described.

[0040] The travel guide plate 5 is preferably a pair of two half-donut-shaped plates as shown in Figures 6 and 7. The travel guide plate 5 is attached around the entire periphery of the first steel pipe pile 1 near its upper end by a guide plate mounting member 6 shown in Figures 3 to 6 and 8. For the travel guide plate 5, it is preferable to use a plate material that is easily available or procured at the construction site, in particular, a scrap material that is easily available at the site, as this is low cost.

[0041] The guide plate mounting member 6 is configured such that, as shown in Figure 3, the vertical line portions 61A of each of a plurality of (eight in this embodiment) inverted L-shaped members 61 are fixed to a bendable long strip plate 62 at any intervals (equidistant intervals in this embodiment), and as shown in Figures 4 to 5, the long strip plate 62 is wrapped around and fixed to the outer circumferential surface of the first steel pipe pile 1 so that the horizontal line portions 61B of each of the plurality of inverted L-shaped members 61 face outward and maintain horizontality, and then, as shown in Figures 6 to 8, a donut-shaped running guide plate 5 is placed and fixed on top of the horizontal line portions 61B of each of the plurality of inverted L-shaped members 61. The guide mounting member 6 is fixed to the first steel pipe pile 1, and with the traveling guide plate 5 placed on it, the level is checked with a spirit level, and if it is not level, the mounting position of the guide mounting member 6 is adjusted.

[0042] The upside-down L-shaped member 61 constituting the guide plate mounting member 6 can be made from steel material or steel scraps that are commonly used at steel construction sites, etc., and are therefore extremely easily available and procured, allowing for low-cost and easy production. Furthermore, the upside-down L-shaped member 6 is not limited to a one-piece molded configuration, and may also be formed into an L-shape by attaching an angle or the like to two members, for example, a flat bar (plate). The long strip plate 62 can also be made from steel materials or steel scraps that are commonly used at this type of steel construction site, etc., and is therefore extremely easy to obtain and procure, making it low-cost and easy to manufacture.

[0043] The vertical line portion 61A can be fixed to the long strip plate 62 by various means such as welding, engagement, clamping, bolting, or adhesive, but welding is preferred. The running guide plate 5 placed on the horizontal line portion 61B can be fixed by various means such as welding, engagement, clamping, bolting, or adhesive, but welding is preferred.

[0044] Although welding or other fastening means can be used to wrap and secure the long strip plate 62 around the outer periphery of the first steel pipe pile 1, not only is it necessary to remove the long strip plate 62 after connecting the lower end of the second steel pipe pile 2 to the upper end of the first steel pipe pile 1, but also in order to enable quick reuse in subsequent connections, such as connecting the lower end of a subsequent steel pipe pile (not shown) to the upper end of the second steel pipe pile 2, it is preferable to wrap a fastening member 7 such as a chain block around the outside of the L-shaped vertical line portions 61A of the multiple upside-down L-shaped members 61 above the long strip plate 62 and fasten it using a jack or the like. A fastening member 7 such as a chain block can be easily and firmly fastened, is easily removed, and is easily available and procured at construction sites, etc., resulting in low cost. The tightening member 7 may be wound around the outer circumferential surface of the long strip-shaped plate 62 .

[0045] According to the configuration in which the welding carriage 4 having the above-mentioned configuration travels circumferentially around the outer peripheral surface of the second steel pipe pile 2 above the joint 3 while being magnetically attracted to the outer peripheral surface, and the roller 43A of the guide roller portion 43 is brought into contact with the upper surface of the traveling guide plate 5 having the above-mentioned configuration to perform welding while tracing the weld line, the welding carriage 4 travels while being magnetically attracted to the outer peripheral surface of the second vertical pile piping 2 due to magnetic attraction, and therefore the weight of the welding carriage 4 and the load during travel are not applied to the traveling guide plate 5, and therefore there is no need for the high-strength traveling rails and the mounting configuration for the high-strength traveling rails used in the technologies shown in Patent Documents 1 to 3 above.

[0046] Furthermore, the welding carriage 4 is configured to follow the weld line by having the rollers 43A of the guide roller section 43 thereof abut against the traveling guide plate 5 attached to the outer peripheral surface of the first steel pipe pile 1 and allowing it to travel freely, so that the traveling carriage 4 can travel accurately while checking the position of its traveling trajectory, thereby achieving accurate and uniform welding quality in a stable state.

[0047] Furthermore, since the roller 43A of the guide roller portion 43, the traveling guide plate 5 against which the roller 43A abuts, the seam 3 to be welded, and the welding torch portion 42 that welds the seam 3 are all positioned close to each other, the deviation in the positional accuracy of each of these can be significantly reduced compared to a configuration in which these positions are far apart.

[0048] Furthermore, since the traveling guide plate 5 is not subjected to the weight of the welding carriage 4 or the load during traveling, the configuration of the traveling guide plate 4 and the configuration for attaching it to the first steel pipe pile 1 can be simple, and parts and scraps that are easily available and procured at construction sites, etc. can be used at low cost. Furthermore, since the configuration of the running guide plate 5 and the configuration for attaching it to the first steel pipe pile 1 are simple and sufficient, once the welding of the joint 3 between the first steel pipe pile 1 and the second steel pipe pile 2 is completed, it becomes easy to relocate the running guide plate 5 when connecting the next steel pipe pile.

[0049] When connecting steel pipe piles using the connection method of the present invention having the above-mentioned configuration, a backing material such as a ring-shaped steel plate may be pre-welded to the inside of the joint 3 between the first steel pipe pile 1 and the second steel pipe pile 2 to prevent misalignment of the connection, or a plate equivalent to the gap between the joint 3 and the bottom end of the second steel pipe pile 2 may be pulled and temporarily welded as preparation for creating a weld backing at the butt joint, and then this plate may be removed. Of course, other known and commonly used work steps in this type of steel pipe pile connection method can also be adopted in the present invention without any special restrictions.

[0050] Although the embodiment of the method for connecting steel pipe piles according to the present invention has been described above, the present invention is not limited to the above configuration and other embodiments can be adopted within the scope of the present invention.

[0051] For example, the mounting configuration of the donut-shaped running guide plate 5 is not limited to the configuration of the above-mentioned embodiment, and as shown in Figure 9, it is also possible to fix multiple L-shaped steel members 63 to the outer surface of the first steel pipe pile 1 via temporary protrusion members 64 so that each L-shaped horizontal wire portion 63B faces outward and maintains horizontality, and then place and fix the donut-shaped running guide plate on top of the L-shaped horizontal wire portion 63B. According to this configuration, the travel guide plate 5 is formed using L-shaped steel material 63, which is a material or offcut that can be easily obtained or procured at construction sites, etc., and therefore can be manufactured easily and at low cost. It is preferable that the butted portion between the circumferential ends of the two travel guide plates 5 is supported by one L-shaped horizontal line portion 63B straddling the lower part of the butted portion.

[0052] Also, as shown in FIG. 10, the welding carriage 4 may have an outer circumferential guide roller portion 44 separate from the guide roller portion 43, and the outer circumferential roller 44A of the outer circumferential guide roller portion 44 may be configured to abut against the donut-shaped outer circumferential position of the traveling guide plate 5 and travel freely. With this configuration, the traveling position of the welding carriage 4 can be confirmed from the outer peripheral position of the traveling guide plate 5, so that the traveling position can be made more accurately. Therefore, accurate and uniform welding quality can be obtained in a more stable state. Furthermore, even if there is a risk of the welding cart 4 coming off due to a weakening of the magnetic attraction force of the magnet body constituting the wheel section 41, vibration during travel, or other factors, the outer circumferential guide roller section 44 will support the welding cart 4 from the outer circumferential position of the travel guide plate 5, thereby preventing or suppressing the coming off. [Explanation of symbols]

[0053] 1. First Steel Pipe Pile 2. Second Steel Pipe Pile 3. Seams 4 Welding trolley 41 Wheel section 42 Welding torch 43 Guide roller part 43A Roller 44 Outer periphery guide roller part 44A Peripheral roller 5 Travel guide plate 6 Guide plate mounting member 61 Upside-down L-shaped member 61A Vertical line section 61B Horizontal line section 62 Long strip plate 63 L type steel material 63B Horizontal line section 64 Temporary protrusion member 7 Fastening members such as chain blocks

Claims

1. A method for connecting steel pipe piles, in which a joint between a first steel pipe pile and a second steel pipe pile connected on top of the first steel pipe pile is welded using a welding device that moves circumferentially around the outer periphery of the steel pipe pile, A donut-shaped running guide plate is attached horizontally around the entire periphery of the first steel pipe pile near the upper end thereof, which is located near the lower portion of the joint; A welding carriage having the following configuration is magnetically attracted to the outer peripheral surface of the second steel pipe pile above the joint while traveling circumferentially around the outer peripheral surface, and welding is performed by traveling the welding carriage while confirming its position by bringing the rollers of the guide roller unit into contact with the upper surface of the traveling guide plate. Two rollers are provided, and the two rollers are configured to contact the traveling guide plate at two points spaced apart in the circumferential direction, and welding is performed by the welding torch at a position between the two points where the rollers are in contact, The contact position of the roller with the traveling guide plate is a position close to the outer circumferential surface of the steel pipe pile, which is a position near the inner periphery of the donut-shaped traveling guide plate, The mounting structure of the donut-shaped traveling guide plate is The L-shaped vertical line portions of each of the multiple inverted L-shaped members are attached to a bendable long strip plate at any interval, and the outer surfaces of the L-shaped vertical line portions are attached and fixed to the inner surfaces of the long strip plate. The long strip plate is wrapped around and fixed to the outer periphery of the first steel pipe pile so that the L-shaped horizontal line portions of each of the multiple inverted L-shaped members face outward and maintain horizontality. After that, a donut-shaped running guide plate is placed on and fixed to each of the L-shaped horizontal line portions of the multiple inverted L-shaped members. A method for connecting steel pipe piles, characterized by: "Welding trolley configuration" The structure comprises a plurality of wheel sections formed mainly from magnet bodies that run and rotate while being magnetically attracted to the outer circumferential surface of the second steel pipe pile by the magnet bodies, a drive mechanism that runs and rotates the wheel sections, a welding torch section that welds the joints at the welding points, and a guide roller section that moves freely and abuts the running guide plate to follow the weld line.

2. A method for connecting steel pipe piles as described in claim 1, characterized in that the welding carriage has an outer guide roller portion separate from the guide roller portion, and the outer roller of the outer guide roller portion abuts against the donut-shaped outer circumferential position of the running guide plate and runs freely.

3. 3. The method for connecting steel pipe piles according to claim 1, wherein the travel guide plate is a pair of half-donut shaped two-piece plates.

4. A method for connecting steel pipe piles according to any one of claims 1 to 3, characterized in that a long strip plate is wrapped around the outer peripheral surface of the first steel pipe pile, and a tightening member is further wrapped around the outer peripheral surface of the long strip plate or the outside of the L-shaped vertical line portions of the multiple upside-down L-shaped members to tighten and fix them.

5. The donut-shaped guide plate is attached as follows: A configuration in which a plurality of L-shaped steel members are fixed to the outer peripheral surface of the first steel pipe pile so that each L-shaped horizontal wire portion faces outward and maintains horizontality, and a donut-shaped traveling guide plate is placed and fixed on the L-shaped horizontal wire portion. The method for connecting steel pipe piles according to any one of claims 1 to 4,

Images