Pipe welding machine and pipe welding method

Abstract

This invention provides a pipe welding machine and pipe welding method that enable easy manual circumferential welding. [Solution] The pipe welding machine 100 comprises a base portion 10 that can be attached to and detached from a pipe, a handle 30 rotatably mounted on the base portion 10, a head 40 that forms an insertion space S1 through which the pipe can be inserted and is rotatably mounted on the base portion 10 along the circumferential direction of the pipe, a transmission portion 80 that transmits the rotational force input to the handle 30 to the head 40, and a torch fixing portion provided on the head 40 to which a torch for welding the pipe can be attached. The head 40 rotates in the circumferential direction together with the torch fixing portion by the rotational force transmitted from the handle 30 via the transmission portion 80.

Description

Technical Field

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[0001] The present invention relates to a pipe welding machine and a pipe welding method.

Background Art

[0002] Conventionally, as a method of connecting pipes, there is a circumferential welding method in which pipes are connected by performing welding along the outer circumferences of two abutting pipes. As a circumferential welding method, there is a manual method using a hand torch. In the conventional manual circumferential welding operation, the operator can obtain a desired welding result without prior condition adjustment by checking the molten state of the pipe and adjusting the welding speed and welding current at any time. Since the conventional manual circumferential welding operation can use a general-purpose welding power source and torch, it does not require the introduction of new equipment and can suppress an increase in equipment costs.

[0003] Also, there is a pipe automatic welding machine that has a mechanism for automatically rotating a torch along the outer circumference of a pipe and automatically performs pipe welding (for example, Patent Document 1). Since the pipe automatic welding machine performs circumferential welding by controlling the torch based on preset welding conditions, it can suppress variations in welding results. The circumferential welding operation using a pipe automatic welding machine does not require advanced skills, so even an operator with little experience in circumferential welding can easily perform it.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, conventional manual circumferential welding requires highly advanced skills, as it necessitates maintaining appropriate welding speed and torch height while monitoring the molten state of the pipe. Therefore, even when the same worker performs multiple circumferential welds, variations in the results may occur. Conventional manual circumferential welding is difficult for workers with little experience, and they may not achieve the desired welding results. Furthermore, conventional manual circumferential welding is slower than circumferential welding using an automatic pipe welding machine, potentially increasing the overall work time.

[0006] Furthermore, when using an automatic pipe welding machine for circumferential welding, it is necessary to adjust the welding conditions in advance to obtain the desired welding result. Adjusting the welding conditions requires preparing a separate pipe (temporary workpiece) from the pipe to be actually processed (actual workpiece), which may increase material costs compared to manual circumferential welding. In addition, when using an automatic pipe welding machine for circumferential welding, it may be necessary to introduce the automatic pipe welding machine and its peripheral equipment, which may increase equipment costs.

[0007] Based on the above circumstances, the present invention aims to provide a pipe welding machine and a pipe welding method that enable circumferential welding work to be easily performed by hand. [Means for solving the problem]

[0008] To solve the above problems, this invention proposes the following means. The pipe welding machine of the present invention comprises a base portion that can be attached to or detached from a pipe, a handle rotatably mounted on the base portion, a head that forms an insertion space through which the pipe can be inserted and is rotatably mounted on the base portion along the circumferential direction of the pipe, a transmission portion that transmits rotational force input to the handle to the head, and a torch fixing portion provided on the head to which a torch for welding the pipe can be attached, wherein the head rotates in the circumferential direction together with the torch fixing portion by the rotational force transmitted from the handle via the transmission portion.

[0009] The pipe welding method of the present invention is a pipe welding method using a pipe welding machine comprising: a handle rotatably mounted on a base portion detachable from a pipe; a head rotatably mounted on the base portion along the circumferential direction of the pipe; a transmission unit for transmitting rotational force input to the handle to the head; and a torch fixing unit to which a torch for welding the pipe can be attached, wherein the handle is rotated, and the rotational force transmitted from the handle via the transmission unit causes the head to rotate together with the torch fixing unit in the circumferential direction. [Effects of the Invention]

[0010] The pipe welding machine and pipe welding method of the present invention provide a pipe welding machine and pipe welding method that allow circumferential welding work to be easily performed by hand. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view showing the front of the pipe welding machine according to this embodiment. [Figure 2] This is a perspective view showing the rear of the pipe welding machine. [Figure 3] This is an enlarged view showing the torch fixing section of the pipe welding machine. [Figure 4] This is a front view showing the transmission section of the pipe welding machine. [Figure 5] This diagram schematically shows the relationship between welding current and time in pulse welding. [Figure 6] This figure shows another modified example of the gripping section of the same pipe welding machine. [Figure 7] This is a photograph showing the welding results of Example 1. [Figure 8] This is a photograph showing the welding results of Example 2. [Figure 9] This is a photograph showing the welding results of Comparative Example 1. [Figure 10] This is a photograph showing the welding results of Comparative Example 2. [Figure 11] This is a photograph showing the welding results of Comparative Example 3. [Figure 12] It is a photograph showing the welding result of Comparative Example 4.

Embodiments for Carrying Out the Invention

[0012] An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the front face of a pipe welding machine 100 according to this embodiment. FIG. 2 is a perspective view showing the rear face of the pipe welding machine 100. FIG. 3 is an enlarged view showing the torch fixing part 60 of the pipe welding machine 100. FIG. 4 is a front view showing the transmission part 80 of the pipe welding machine 100.

[0013] The pipe welding machine 100 includes a base part 10, a gripping part 20, a handle 30, a head 40, a locking part 50, a torch fixing part 60, a torch 70, and a transmission part 80. In FIGS. 1 and 2, the torch 70 is omitted.

[0014] The pipe welding machine 100 is a welding machine capable of welding pipes together by circumferential welding. Circumferential welding refers to a welding method in which pipes are connected by performing welding along the outer circumference of two abutting pipes.

[0015] In this embodiment, the pipe welding machine 100 when circumferentially welding a pipe fixed in a posture where the axis is parallel to the horizontal direction will be described. Note that the pipe welding machine 100 may also be used for circumferential welding of a pipe fixed in a posture where the axis is parallel to the vertical direction.

[0016] In this embodiment, as shown in FIGS. 1 and 2, the vertical direction in the pipe welding machine 100 is defined as the "vertical direction Z", the vertically upward direction is defined as the "upper direction Z1" in the vertical direction Z, and the vertically downward direction is defined as the "lower direction Z2" in the vertical direction Z. Further, among the horizontal directions orthogonal to the vertical direction Z, the direction (axial direction) in which the axis of the pipe to be subjected to circumferential welding extends is defined as the "front-rear direction Y", the direction in which the operator who performs the circumferential welding operation is mainly located is defined as the "front direction Y1" in the front-rear direction Y, and the direction opposite to the front direction Y1 in the front-rear direction Y is defined as the "rear direction Y2". Further, the direction orthogonal to the vertical direction Z and the front-rear direction Y is defined as the "left-right direction X", one in the left-right direction X is defined as the "left direction X1", and the other is defined as the "right direction X2" in the left-right direction X.

[0017] The base portion 10 is the base of the pipe welding machine 100. The base portion 10 includes a base portion main body 11 to which components such as the transmission portion 80 in the pipe welding machine 100 are attached, a lid portion 12 that mainly forms the front surface (front surface) of the base portion 10 in the front direction Y1, a support portion 13, a first fixing portion 14, and a lock fixing portion 15. The base portion 10 is detachable from the pipe to which circumferential welding is to be performed. The method of attaching and detaching the base portion 10 to and from the pipe will be described later.

[0018] The lid portion 12 is a cover member that covers the transmission portion 80 (see FIG. 4) attached inside the base portion 10 from the front direction Y1. By attaching the lid portion 12 to the base portion main body 11, it is possible to prevent the components of the pipe welding machine 100 from being damaged by spatter or the like during the circumferential welding operation. The support portion 13, the first fixing portion 14, and the lock fixing portion 15 will be described later.

[0019] The grip portion 20 is a member connected to the upper direction Z1 of the base portion 10 and can be gripped by an operator. The grip portion 20 has a grip opening 20h that penetrates the grip portion 20 in the front-rear direction Y. The operator can easily carry the pipe welding machine 100 by inserting a finger into the grip opening 20h and gripping the upper end of the grip portion 20. In this embodiment, the grip portion 20 extends upward from the upper end portion of the base portion 10 in the upper direction Z1.

[0020] The handle 30 is mounted on the base portion 10 so as to be rotatable around an axis O1 extending in the front-rear direction Y (circumferential direction A). The handle 30 has a shape that allows it to be rotated in the circumferential direction A using a general-purpose tool. In this embodiment, the front end 30a of the handle 30 at Y1 has a hexagonal shaft shape. The operator can easily rotate the handle 30 in the circumferential direction A by fitting a general-purpose tool such as a ratchet wrench, socket wrench, or electric screwdriver onto the end 30a of the handle 30. The handle 30 only needs to be able to connect to a general-purpose tool and can have an appropriate shape corresponding to the tool connected to the handle 30.

[0021] As shown in Figures 1 and 2, the handle 30 is provided so as to penetrate the base portion 10 in the front-rear direction Y. In this embodiment, the rear end 30b of the handle 30 at Y2 has a hexagonal shaft shape, similar to the front end 30a at Y1. Therefore, the operator can fit a tool such as a ratchet wrench onto the handle 30 from either the front Y1 or rear Y2.

[0022] The head 40 is rotatably mounted on the base portion 10 around an axis O2 extending in the front-rear direction Y (circumferential direction B). The head 40 forms an insertion space S1 through which a pipe to be circumferentially welded is inserted. In this embodiment, the central axis of the pipe inserted into the insertion space S1 coincides with axis O2. However, axis O2 does not need to strictly coincide with the central axis of the pipe inserted into the insertion space S1.

[0023] The head 40 rotates in the circumferential direction B, thereby rotating along the circumferential direction of the pipe inserted into the insertion space S1. The circumferential direction of the pipe refers to the direction along the outer circumference of the pipe. In this embodiment, the central axis of the pipe inserted into the insertion space S1 coincides with axis O2, and the circumferential direction of the pipe coincides with circumferential direction B.

[0024] Hereinafter, the direction approaching or moving away from axis O2 in a direction perpendicular to axis O2 will be referred to as the "radial direction R (see Figure 4)". The head 40 has a head opening 40h that opens in the radial direction R and communicates with the insertion space S1. Here, the head 40 shown in Figures 1, 2, 3, and 4 is positioned so that the head opening 40h opens downward Z2. In this embodiment, the position of the head 40 where the head opening 40h opens downward Z2 is defined as the initial position of the head 40. By rotating the head 40 in the circumferential direction B from the initial position, the direction in which the head opening 40h opens is changed to a direction different from downward Z2.

[0025] The base body 11 has a base opening 11h that opens downward Z2. When the head 40 is in its initial position, the insertion space S1 communicates with the external space of the base 10 through the head opening 40h and the base opening 11h that open downward Z2.

[0026] The head 40 is rotatably supported in the circumferential direction B by the support portion 13. In this embodiment, the base portion 10 has a plurality of support portions 13. The support portion 13 also includes bearings.

[0027] As shown in Figure 1, a groove 40a is formed on the rear surface Y2 of the head 40, recessed in front Y1. The groove 40a is formed around the entire circumference of the head 40 in the circumferential direction B.

[0028] Multiple support parts 13 are provided on the base body 11. The multiple support parts 13 are arranged at equal intervals in the circumferential direction B at positions corresponding to the groove 40a. When the head 40 rotates in the circumferential direction B, it can rotate smoothly by being supported by the multiple bearings (support parts 13) located inside the groove 40a.

[0029] By using a bearing as the support part 13 that supports the head 40 so that it can rotate in the circumferential direction B, the frictional force generated between the head 40 and the support part 13 can be reduced, thereby suppressing wear of the head 40 when it rotates in the circumferential direction B.

[0030] For example, if the head 40 is made of a hard material such as metal, the possibility of wear on the head 40 is low, so a rail member or the like may be used as the support part 13 that rotatably supports the head 40. If the head 40 is made of a material softer than metal, such as resin, it is preferable to use a bearing as the support part 13 in order to suppress wear on the head 40.

[0031] The locking portion 50 is provided so as to be rotatable around an axis O3 extending in the front-rear direction Y (circumferential direction C). In this embodiment, as shown in Figure 2, the axis O3 is located to the left X1 of the insertion space S1. The locking portion 50 comprises a locking portion body 51 rotatably mounted on the base portion 10 in the circumferential direction C, a second fixing portion 52 fixed to the locking portion body 51, and a fixed portion 53.

[0032] The locking mechanism 50 is positioned as shown in Figure 2 when fixing the piping in the insertion space S1. The piping to which circumferential welding is performed is mainly cylindrical in shape. The piping placed in the insertion space S1 is fixed by the first fixing part 14 of the base part 10 and the second fixing part 52 of the locking mechanism 50.

[0033] In this embodiment, the first fixing portion 14 is a member having an arc shape along the outer circumference Z1 above the central axis (axis O2) of the pipe arranged in the insertion space S1. The second fixing portion 52 is a member having an arc shape along the outer circumference Z2 below the central axis (axis O2) of the pipe arranged in the insertion space S1.

[0034] The piping placed in the insertion space S1 is sandwiched between the first fixing part 14 and the second fixing part 52 in the vertical direction Z, and is fixed in a predetermined position within the insertion space S1. At this time, the first fixing part 14 and the second fixing part 52 contact the piping along its outer circumferential surface, holding the piping in the insertion space S1.

[0035] The shapes of the first fixing part 14 and the second fixing part 52 can be appropriately changed depending on the size and shape of the piping to be placed in the insertion space S1. The first fixing part 14 may be detachably attached to the base part body 11. The second fixing part 52 may also be detachably attached to the lock part body 51.

[0036] By preparing multiple first fixing parts 14 and second fixing parts 52 with different shapes, and appropriately using the first fixing parts 14 and second fixing parts 52 corresponding to the shape of the pipe to be circumferentially welded, the pipe welding machine 100 can handle circumferential welding of pipes of various shapes and sizes.

[0037] The first fixing part 14 is attached to the base body 11 by, for example, a single fastening member. The second fixing part 52 is attached to the lock body 51 by, for example, a single fastening member. By attaching the first fixing part 14 and the second fixing part 52 to the base body 11 or the lock body 51 using a single fastening member, the first fixing part 14 and the second fixing part 52 can be easily attached to and detached from the base body 11 or the lock body 51. This allows workers to easily replace the first fixing part 14 and the second fixing part 52 with those corresponding to the size of the piping.

[0038] Furthermore, it is preferable to use anti-loosening screws for the fastening members that fix the first fixing part 14 and the second fixing part 52 to the base part body 11 or the lock part body 51. This prevents the fastening members from falling off when replacing the first fixing part 14 and the second fixing part 52, and makes the replacement work of the first fixing part 14 and the second fixing part 52 easier.

[0039] The first fixing portion 14 and the second fixing portion 52 are not limited to the above shapes, as long as they can fix the piping in the insertion space S1. For example, the first fixing portion 14 and the second fixing portion 52 may be divided into multiple parts and provided so as to partially contact the outer surface of the piping.

[0040] The fixed portion 53 is provided at the tip of the lock body 51 and is a member having a shape that allows the lock portion 50 to be fixed to the base portion 10. The lock portion 50 is fixed to the base portion 10 by the lock fixing portion 15 of the base portion 10 and is held in the position shown in Figure 2.

[0041] The lock fixing portion 15 is mounted on the base body 11 so as to be rotatable around an axis O4 extending in the front-rear direction Y (circumferential direction D). The lock fixing portion 15 has a small diameter portion 15a and a large diameter portion 15b. The small diameter portion 15a is a cylindrical member attached to the base body 11 so as to be rotatable in the circumferential direction D. The large diameter portion 15b is a cylindrical member provided at the tip of the small diameter portion 15a and has a larger diameter than the small diameter portion 15a.

[0042] The fixed portion 53 has a groove shape into which the small diameter portion 15a can be fitted. When the lock portion 50 is fixed to the base portion 10, the lock fixing portion 15 is positioned with the large diameter portion 15b facing downward Z2. At this time, the small diameter portion 15a is fitted into the fixed portion 53. The diameter of the small diameter portion 15a is smaller than the dimensions of the groove shape of the fixed portion 53. Also, the diameter of the large diameter portion 15b is larger than the dimensions of the groove shape of the fixed portion 53.

[0043] When piping is placed in the insertion space S1, the locking mechanism 50 is positioned at a location rotated from the position shown in Figure 2 in the first rotational direction C1 in the circumferential direction C. At this time, the locking mechanism 50 is not positioned below the insertion space S1 Z2, but is positioned at a location rotated toward the axis O3 side (in this case, to the left X1) from the insertion space S1.

[0044] When the head 40 is in the initial position shown in Figure 1, the insertion space S1 is in communication with the external space of the base portion 10 through the head opening 40h and the base opening 11h. Specifically, the insertion space S1 opens downward Z2 through the head opening 40h and the base opening 11h.

[0045] When the locking mechanism 50 is positioned as shown in Figure 2, it is located below Z2 of the insertion space S1. Specifically, the locking mechanism 50 is located below Z2 of a portion of the rear Y2 side of the insertion space S1. At this time, the locking mechanism 50 is positioned so as to overlap the head opening 40h and the base opening 11h when viewed from the front-rear direction Y.

[0046] The operator can fix the lock part 50 to the base part 10 by rotating the lock fixing part 15 in the first rotational direction D1 in the circumferential direction D. The operator can also release the lock part 50 fixed to the base part 10 by rotating the lock fixing part 15 in the second rotational direction D2 in the circumferential direction D.

[0047] The lock fixing portion 15 shown in Figure 2 has a small diameter portion 15a that fits into the fixed portion 53. The large diameter portion 15b is positioned below the fixed portion 53 by Z2. In this case, the downward movement of the fixed portion 53 by Z2 is hindered by the large diameter portion 15b. Therefore, the lock portion 50 does not rotate in the first rotational direction C1 and is held in the position shown in Figure 2.

[0048] When the worker releases the locking mechanism 50, they rotate the locking mechanism 15 in the second rotational direction D2. This causes the large-diameter portion 15b to move to the right X2 of the fixed portion 53, making the locking mechanism 50 rotatable in the first rotational direction C1. The locking mechanism 50 is rotated in the first rotational direction C1 by gravity and the worker's hand, moving to the left X1 of the insertion space S1.

[0049] As a result, the entire insertion space S1 opens downwards to Z2, and the insertion space S1 communicates with the external space of the base portion 10. The operator, for example, grasps the gripping portion 20 and lowers the pipe welding machine 100 from above Z1 to below Z2 of the pipe so that the pipe is positioned in the insertion space S1. At this time, at least a portion of the upper surface of the pipe comes into contact with the first fixing portion 14.

[0050] Next, the operator rotates the locking part 50 in the second rotational direction C2 and the lock fixing part 15 in the first rotational direction D1 to fix the locking part 50 in the position shown in Figure 2. At this time, at least a portion of the lower surface of the pipe comes into contact with the second fixing part 52. In this way, the operator can attach and detach the base part 10 of the pipe welding machine 100 to the pipe by operating the locking part 50 and the lock fixing part 15. By securely fixing the pipe in the insertion space S1 with the first fixing part 14 and the second fixing part 52, the posture of the pipe welding machine 100 is maintained even when the operator releases their hand from the gripping part 20.

[0051] The small-diameter portion 15a is inserted, for example, into a screw hole formed inside the large-diameter portion 15b and connected to the large-diameter portion 15b by screwing it in. In the lock fixing portion 15 shown in Figure 2, the large-diameter portion 15b is rotatably mounted relative to the small-diameter portion 15a with an axis (rotation axis) extending in the vertical direction Z as the center of rotation. By rotating around the rotation axis, the large-diameter portion 15b moves forward and backward relative to the small-diameter portion 15a. In the lock fixing portion 15 shown in Figure 2, the position of the lock portion 50 in the vertical direction Z can be adjusted by moving the large-diameter portion 15b forward and backward. This allows the fixing force that secures the piping by the first fixing portion 14 and the second fixing portion 52 to be adjusted, and the piping can be securely fixed.

[0052] The torch fixing part 60 is a component that can fix the torch 70 used for welding pipes to the base part 10. As shown in Figure 3, the torch fixing part 60 comprises a fixing part body 61, an adjustment part 62, and an adjustment shaft 63. Details of the fixing part body 61, adjustment part 62, and adjustment shaft 63 will be described later.

[0053] The torch 70 comprises a welding torch 71 and a fixing jig 72. The welding torch 71 is a welding torch capable of welding metal such as pipes. For example, an operator can perform circumferential welding of a pipe by applying arc welding, such as TIG (Tungsten Inert Gas) welding, to the pipe using the welding torch 71.

[0054] A supply line (not shown) is connected to the base end 71a of the welding torch 71 to supply current and gas for welding. An electrode for TIG welding is provided at the tip 71b of the welding torch 71. The welding torch 71 can weld pipes by supplying current to the electrode at the tip 71b and releasing shielding gas from the tip 71b. When the torch 70 is attached to the torch fixing part 60, the tip 71b of the welding torch 71 is positioned facing axis O2.

[0055] The welding torch 71 is fixed to a fixing jig 72. The welding torch 71 is fixed to the head 40 via the fixing jig 72 and the torch fixing part 60. The fixing jig 72 has a shape that can be fitted into the torch fixing part 60. The fixing jig 72 is fixed by being sandwiched in the vertical direction Z by the fixing part body 61 and the adjustment part 62.

[0056] The fixed part body 61 is fixed to the head 40. The adjustment part 62 is provided on the fixed part body 61 and is a member that can move toward or away from the fixed part body 61. The adjustment shaft 63 is provided on the fixed part body 61. The adjustment shaft 63 is rotatable, for example, around the axis O5 shown in Figure 3, and moves forward and backward relative to the fixed part body 61 by rotating around the axis O5.

[0057] When the head 40 is in its initial position, the shaft O5 extends in the vertical direction Z, as shown in Figure 3. At this time, by rotating the adjustment shaft 63 around the shaft O5 and moving it back and forth in the vertical direction Z, the position of the adjustment part 62, which is positioned between the fixed part body 61 and the adjustment shaft 63, can be changed in the vertical direction Z. By moving the adjustment part 62 toward the fixed part body 61 (downward in this case Z2), the fixing jig 72 sandwiched between the fixed part body 61 and the adjustment part 62 can be fixed to the torch fixed part 60. Conversely, by moving the adjustment part 62 toward the side away from the fixed part body 61 (upward in this case Z1), the fixing jig 72 to the torch fixed part 60 can be released.

[0058] The fixing jig 72 is provided between the fixing body 61 and the adjustment part 62 so as to be movable in the radial direction R. After adjusting the position of the fixing jig 72 in the radial direction R, the operator fixes the fixing jig 72 to the torch fixing part 60 by tightening the adjustment shaft 63, thereby fixing the position of the fixing jig 72 in the radial direction R. This allows the operator to adjust the position of the welding torch 71 connected to the fixing jig 72 in the radial direction R, and to adjust the distance between the piping located in the insertion space S1 and the tip 71b of the welding torch 71.

[0059] The torch 70 is detachably attached to the torch fixing part 60. By removing the torch 70 from the torch fixing part 60 and fixing the piping in the insertion space S1, the worker can perform the piping fixing work without being obstructed by the supply line connected to the torch 70. The torch fixing part 60 and the torch 70 are not limited to the above configuration, as long as the torch 70 can be fixed to the head 40 and the position of the torch 70 in the radial direction R can be adjusted.

[0060] The transmission unit 80 is a transmission mechanism capable of transmitting the rotational force input to the handle 30 to the head 40. In this embodiment, the head 40 and the transmission unit 80 have a gear structure that meshes with each other. As shown in Figure 4, a transmitted portion 41 is formed on the outer circumference of the head 40, with a plurality of teeth that protrude outward in the radial direction R at equal intervals. The outer side in the radial direction R refers to the side away from the axis O2 in the radial direction R. Note that in Figure 4, the cover 12, the torch fixing portion 60, and the torch 70 are omitted.

[0061] The transmission unit 80 comprises a first transmission unit (handle-side gear) 81, a second transmission unit 82, a third transmission unit 83, and a fourth transmission unit (head-side gear) 84. The first transmission unit 81 is connected to the handle 30. When a rotational force in the circumferential direction A is input to the handle 30, the first transmission unit 81 rotates together with the handle 30 in the circumferential direction A.

[0062] The second transmission unit 82 is mounted on the base unit 10 so as to be rotatable around an axis O6 extending in the front-rear direction Y. The second transmission unit 82 is a two-stage gear having a first-stage main gear 82a and a second-stage auxiliary gear 82b. The main gear 82a of the first transmission unit 81 and the second transmission unit 82 are gears that mesh with each other. When a rotational force in the circumferential direction A is input to the handle 30, the rotational force is transmitted to the main gear 82a of the second transmission unit 82 via the first transmission unit 81, causing the second transmission unit 82 to rotate around the axis O6. At this time, the auxiliary gear 82b rotates together with the main gear 82a around the axis O6.

[0063] The third transmission unit 83 is mounted on the base unit 10 so as to be rotatable around an axis O7 extending in the front-rear direction Y. In this embodiment, the transmission unit 80 has a pair of third transmission units 83 provided on both sides of the axis O6 in the left-right direction X. The auxiliary gear 82b of the second transmission unit 82 and the third transmission unit 83 are gears that mesh with each other. When a rotational force in the circumferential direction A is input to the handle 30, the rotational force is transmitted to the third transmission unit 83 via the first transmission unit 81 and the second transmission unit 82, causing the third transmission unit 83 to rotate around the axis O7.

[0064] The fourth transmission unit 84 is mounted on the base unit 10 so as to be rotatable around an axis O8 extending in the front-rear direction Y. The third transmission unit 83 and the fourth transmission unit 84 are gears that mesh with each other. In this embodiment, the transmission unit 80 has a pair of fourth transmission units 84 corresponding to a pair of third transmission units 83. When a rotational force in the circumferential direction A is input to the handle 30, the rotational force is transmitted to the fourth transmission unit 84 via the first transmission unit 81, the second transmission unit 82, and the third transmission unit 83, causing the fourth transmission unit 84 to rotate around the axis O8.

[0065] The pair of fourth transmission units 84 are engaged with the transmitted unit 41 of the head 40. When a rotational force in the circumferential direction A is input to the handle 30, the rotational force is transmitted to the head 40 via the first transmission unit 81, the second transmission unit 82, the third transmission unit 83, and the fourth transmission unit 84, causing the head 40 to rotate in the circumferential direction B.

[0066] When the head 40 rotates in the circumferential direction B, the torch 70 fixed to the head 40 rotates with the head 40 in the circumferential direction B with axis O2 as the center of rotation. At this time, the tip 71b of the welding torch 71 rotates in the circumferential direction B while maintaining an orientation facing axis O2. When piping is placed in the insertion space S1, the welding torch 71 rotates in the circumferential direction B while maintaining an orientation with its tip 71b facing the outer surface of the piping, due to the rotational force input to the handle 30.

[0067] In the front view shown in Figure 4, when the handle 30 is rotated clockwise (first rotation direction A1 in circumferential direction A), the head 40 rotates clockwise (first rotation direction B1 in circumferential direction B). Also, when the handle 30 is rotated counterclockwise (second rotation direction A2 in circumferential direction A), the head 40 rotates counterclockwise (second rotation direction B2 in circumferential direction B). In other words, the rotation directions of the handle 30 and the head 40 are the same. Therefore, the operator can easily grasp the rotation direction of the head 40 and rotate the head 40 in the desired direction (first rotation direction B1 or second rotation direction B2) by rotating the handle 30.

[0068] The transmission unit 80 is preferably configured to transmit the rotational force input to the handle 30 to the head 40 at a gear ratio within the range of 1 / 15 to 1 / 20. The gear ratio within the range of 1 / 15 to 1 / 20 includes the gear ratios of 1 / 15 and 1 / 20. In this embodiment, the number of teeth of the first transmission unit 81, the main gear 82a, the sub-gear 82b, the third transmission unit 83, and the fourth transmission unit 84 are 21, 60, 21, 55, and 26, respectively.

[0069] Furthermore, the head 40 is a gear with a portion cut out by the head opening 40h. In this embodiment, the head 40 is a gear with 120 teeth, assuming that the transmitted portion 41 is formed around its entire circumference. In this embodiment, the transmission portion 80 transmits the rotational force input to the handle 30 to the head 40 at a gear ratio of 1 / 16.3.

[0070] Next, a pipe welding method using the pipe welding machine 100 will be described. The following describes a pipe welding method when welding pipes together by circumferential welding, where the circumferences of the ends are butted together. The ends of the two butted pipes are temporarily fixed together, for example, by tack welding. The pipe welding method described below describes a pipe welding method when circumferential welding is performed on this temporarily fixed portion and then the main welding is performed to connect the two pipes.

[0071] First, the operator grasps the gripping part 20 and moves the pipe welding machine 100 so that the pipe is positioned in the insertion space S1. At this time, the torch 70 may be removed from the torch fixing part 60. The head 40 is initially positioned so that the head opening 40h opens downward Z2. If the head 40 is not in the initial position, the operator rotates the handle 30 to rotate the head 40 to the initial position.

[0072] Furthermore, the operator releases the lock portion 50 from the base portion 10 by rotating the lock fixing portion 15 in the second rotational direction D2 in the circumferential direction D. The operator then rotates the lock portion 50 in the first rotational direction C1 in the circumferential direction C, opening the entire insertion space S1 downwards Z2. This connects the entire insertion space S1 with the external space of the base portion 10, allowing the piping to be placed in the insertion space S1 via the base opening 11h and the head opening 40h that are opened downwards Z2.

[0073] After the piping is positioned in the insertion space S1, the worker rotates the locking part 50 in the second rotational direction C2 in the circumferential direction C. The worker rotates the lock fixing part 15 in the first rotational direction D1 in the circumferential direction D, and fixes the locking part 50 to the base part 10 with the lock fixing part 15. The worker adjusts the position of the locking part 50 by, for example, tightening the large diameter part 15b, and fixes the piping by sandwiching it between the first fixing part 14 and the second fixing part 52. When fixing the piping in the insertion space S1, the worker adjusts the relative position of the pipe welding machine 100 and the piping in the front-rear direction Y to the desired position.

[0074] If the torch 70 has been removed from the torch fixing part 60, the worker attaches the torch 70 to the torch fixing part 60. At this time, the worker adjusts the position of the torch 70 in the radial direction R so that the distance from the tip 71b of the welding torch 71 to the outer surface of the pipe is the desired distance. The worker rotates the adjustment shaft 63 around the axis O5 and tightens it, and fixes the torch 70 to the torch fixing part 60 by sandwiching the fixing jig 72 between the fixing part body 61 and the adjustment part 62.

[0075] Next, the operator operates a welding power supply connected to the base end 71a of the welding torch 71 via a supply line to supply current to the torch 70. The operator may also operate a gas supply device and a wire supply device as needed to supply shielding gas and wire to the welding site. The shielding gas and wire may be supplied to the torch 70 and then supplied to the welding site from the tip 71b of the welding torch 71. The operator may also supply an inert gas such as argon gas to the internal space of the piping.

[0076] Next, the operator rotates the handle 30 in the circumferential direction A, thereby rotating the head 40 and torch 70 in the circumferential direction B, and performs circumferential welding on the pipe. The operator can perform the welding work while checking the molten state of the welding area by, for example, rotating the handle 30 from the front Y1 of the pipe welding machine 100.

[0077] The operator may rotate the handle 30 by directly gripping it with their hand, or by rotating a tool fitted to the handle 30. In this embodiment, the end 30a of the handle 30 has a hexagonal shaft shape. The operator connects a general-purpose tool that can be fitted to the hexagonal shaft-shaped end 30a to the handle 30 and rotates the handle 30.

[0078] Examples of general-purpose tools that can be connected to the handle 30 include ratchet wrenches, socket wrenches, electric screwdrivers, or flexible sockets. In the pipe welding method using the pipe welding machine 100, for example, pulse welding is performed in which the current changes in a pulse-like manner.

[0079] Figure 5 schematically shows the relationship between welding current and time in pulse welding. In Figure 5, the vertical axis represents the welding current, and the horizontal axis represents time. In pulse welding, the welding current changes in a pulse-like manner between a base current and a peak current at regular time intervals. Also, in pulse welding, a pulse sound is generated when the welding current changes between the base current and the peak current.

[0080] The operator can rotate the handle 30 at a constant rhythm by starting or stopping its rotation at the timing of the pulse sound. For example, the operator starts rotating the handle 30 at the timing of the pulse sound and stops it at the timing of the next pulse sound. In this way, the operator repeatedly starts and stops the rotation of the handle 30 in accordance with the timing of the pulse sound. By rotating the handle 30 in accordance with the timing of the pulse sound, the operator can easily operate the handle 30 at a constant rhythm.

[0081] Conventionally, there are tools (for example, ratchet wrenches) that generate a sound each time they are rotated by a predetermined angle. By using a tool that generates a sound each time it is rotated by a predetermined angle, the operator can rotate the handle 30 at a constant rhythm and angle by timing the pulse sound with the sound generated by the tool. This makes it possible to obtain a uniform and aesthetically pleasing weld bead.

[0082] For example, the angle at which the handle 30 can be easily rotated in a single operation is approximately 45 degrees (1 / 8 rotation). Also, by setting the angle at which the head 40 advances in a single pulse (head advance angle) to approximately 2.5 degrees, good welding results can be obtained. By setting the gear ratio when the transmission unit 80 transmits rotational force from the handle 30 to the head 40 to within the range of 1 / 15 to 1 / 20, the head advance angle when the handle 30 is rotated approximately 45 degrees can be set to approximately 2.5 degrees. Therefore, by transmitting rotational force from the handle 30 to the head 40 with a gear ratio within the range of 1 / 15 to 1 / 20, a pipe welding machine 100 that is easy for the operator to operate and can produce good welding results can be realized.

[0083] Furthermore, if the gear ratio used by the transmission unit 80 to transmit rotational force from the handle 30 to the head 40 is set within the range of 1 / 15 to 1 / 20, circumferential welding can be performed at a welding speed equivalent to that of a conventional automatic pipe welding machine (approximately 50 mm / min), improving construction efficiency compared to conventional manual circumferential welding.

[0084] When performing circumferential welding using conventional automatic pipe welding machines, it is necessary to pre-adjust the welding conditions to obtain the desired welding result. Adjusting the welding conditions requires preparing a separate pipe (a temporary workpiece) from the pipe that will actually be processed (the actual workpiece).

[0085] With circumferential welding using the pipe welding machine 100, the operator can proceed with the welding work while checking the molten state, just as with conventional manual circumferential welding. Therefore, with circumferential welding using the pipe welding machine 100, there is no need to set welding conditions in advance or prepare temporary workpieces, and the effort required to set welding conditions and the material costs for temporary workpieces can be reduced compared to using conventional automatic pipe welding machines. In addition, with circumferential welding using the pipe welding machine 100, circumferential welding can be easily performed without introducing expensive automatic pipe welding machines, thus suppressing increases in equipment costs.

[0086] After completing circumferential welding at the desired welding location on the pipe, the worker operates the lock fixing part 15 and the lock part 50 to release the lock part 50 and remove the pipe welding machine 100 from the pipe. At this time, the worker can move the torch 70 to a position that facilitates the removal of the pipe welding machine 100 by operating the handle 30. The worker may also remove the torch 70 from the torch fixing part 60 before removing the pipe welding machine 100 from the pipe. The worker removes the pipe welding machine 100 from the pipe and completes the circumferential welding work with the pipe welding machine 100.

[0087] The pipe welding machine 100 of this embodiment includes a base portion 10 that can be attached to and detached from a pipe, a handle 30 rotatably mounted on the base portion 10, a head 40 that forms an insertion space S1 through which a pipe can be inserted and is rotatably mounted on the base portion 10 along the circumferential direction (circumferential direction B) of the pipe, a transmission portion 80 that transmits the rotational force input to the handle 30 to the head 40, and a torch fixing portion 60 provided on the head 40 to which a torch 70 for welding the pipe can be attached. The head 40 rotates in the circumferential direction of the pipe together with the torch fixing portion 60 by the rotational force transmitted from the handle 30 via the transmission portion 80.

[0088] With a pipe welding machine 100 configured in this way, the operator can rotate the head 40 together with the torch fixing part 60 in the circumferential direction of the pipe by rotating the handle 30, thereby easily performing circumferential welding of the pipe.

[0089] Therefore, according to the pipe welding machine 100 and pipe welding method of this embodiment, it is possible to provide a pipe welding machine 100 and pipe welding method that can easily perform circumferential welding work by hand.

[0090] Traditional manual circumferential welding requires highly advanced skills, as it necessitates maintaining appropriate welding speed and torch height while monitoring the molten state of the pipe. Therefore, even when the same worker performs multiple circumferential welds, variations in the results can occur. Furthermore, traditional manual circumferential welding is difficult for workers with limited experience, potentially resulting in unsatisfactory results. Additionally, traditional manual circumferential welding is a burdensome task for elderly workers.

[0091] By using the pipe welding machine 100 of this embodiment, even when inexperienced or elderly workers perform circumferential welding, the burden on the worker can be reduced, and stable welding results can be obtained.

[0092] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the spirit of the present invention are also included. Furthermore, the components shown in the above-described embodiment and the following modifications can be combined as appropriate.

[0093] (Variation 1) In the above embodiment, the gripping portion 20 extends upward Z1 from the upper end of the base portion 10, but the shape of the gripping portion is not limited thereto. The gripping portion may have a shape that protrudes from the base portion 10 in the front-rear direction Y.

[0094] Figure 6 shows a gripping portion 20A according to another modified example 1 of the gripping portion 20. As shown in Figure 6, the gripping portion 20A comprises a pair of first gripping members 21A and a second gripping member 22A. The pair of first gripping members 21A are positioned on both sides in the left-right direction X of the upper end 10t of the base portion 10 and are connected to the base portion 10. The first gripping members 21A extend rearward Y2 as they are directed upward Z1.

[0095] The second gripping member 22A extends in the left-right direction X and connects the upper ends of the pair of first gripping members 21A. The pair of first gripping members 21A, the second gripping member 22A, and the upper end 10t of the base portion 10 form a gripping opening 20Ah through which an operator can insert their fingers.

[0096] By providing a gripping portion 20A on the base portion 10 that protrudes in the front-rear direction Y (rearward Y2 in this case) from the base portion 10, the operability when installing a pipe welding machine on a pipe can be improved, for example.

[0097] (Modification 2) In the above embodiment, the pipe welding machine 100 is configured so that the handle 30 can be rotated by the operator's hand, but the configuration of the pipe welding machine is not limited thereto. The pipe welding machine may also be equipped with a rotation speed adjustment mechanism that can adjust the rotation speed of the handle 30.

[0098] As a rotation speed adjustment mechanism, for example, a flywheel can be used. By connecting a flywheel to the handle 30, the handle 30 can be rotated using the inertial force generated when the handle 30 is rotated by the operator. By providing a rotation speed adjustment mechanism such as a flywheel, the rotation speed of the handle 30 can be kept constant, and the operator's rotation of the handle 30 can be assisted.

[0099] The present invention will be described in detail with reference to the following examples. The present invention is not limited to the following examples.

[0100] (Example 1) In Example 1, circumferential welding of a pipe was performed using a pipe welding machine 100 in which the gear ratio of the transmission unit 80 when transmitting rotational force from the handle 30 to the head 40 was 1 / 16.3. The pipe to be circumferentially welded had a diameter of φ50.8 mm and a wall thickness of 3 mm, and was made of SUS304 material. The welding conditions were a peak current of 90 A, a base current of 40 A, and a pulse frequency of 1.0 Hz. The angle at which the head 40 advanced with one pulse (head advance angle) was 2.3 degrees.

[0101] (Example 2) In Example 2, circumferential welding of a pipe was performed using a pipe welding machine 100 in which the gear ratio when the transmission unit 80 transmits rotational force from the handle 30 to the head 40 was 1 / 20. The shape and material of the pipe to be circumferentially welded were the same as in Example 1. The welding conditions were the same as in Example 1. The head advance angle was 1.3 degrees.

[0102] (Comparative Example 1) In Comparative Example 1, circumferential welding of a pipe was performed using a pipe welding machine in which the gear ratio for transmitting rotational force from the handle to the head was 1 / 5. The shape and material of the pipe to be circumferentially welded were the same as in Example 1. The welding conditions were the same as in Example 1. The head advance angle was 9.1 degrees.

[0103] (Comparative Example 2) In Comparative Example 2, circumferential welding of a pipe was performed using a pipe welding machine in which the gear ratio for transmitting rotational force from the handle to the head was 1 / 10. The shape and material of the pipe to be circumferentially welded were the same as in Example 1. The welding conditions were the same as in Example 1. The head advance angle was 4.5 degrees.

[0104] (Comparative Example 3) In Comparative Example 3, circumferential welding of a pipe was performed using a pipe welding machine in which the gear ratio for transmitting rotational force from the handle to the head was 1 / 35. The shape and material of the pipe to be circumferentially welded were the same as in Example 1. The welding conditions were the same as in Example 1. The head advance angle was 1.3 degrees.

[0105] (Comparative Example 4) In Comparative Example 4, circumferential welding of a pipe was performed using an automatic pipe welding machine (Mobile Welder OC+) and an automatic pipe welding head (OW76S) manufactured by Orbitalum. The shape and material of the pipe to be circumferentially welded were the same as in Example 1. Furthermore, circumferential welding was performed under welding conditions that had been pre-adjusted to allow for proper circumferential welding using the above-mentioned automatic pipe welding machine and automatic pipe welding head. Since Comparative Example 4 involves circumferential welding using an automatic pipe welding machine and automatic pipe welding head rather than manual welding, Comparative Example 4 will also be referred to as a "reference example" in the following description.

[0106] (Evaluation Method 1) In Evaluation Method 1, the circumferential welding results of Example 1-2 and Comparative Example 1-4 were evaluated focusing on the indentation of the weld bead.

[0107] The evaluation criteria consisted of three levels, with all levels except 1 (Poor) being considered passing. 4 (Excellent): No bead indentation. 3 (Good): There is a slight indentation in the bead. 1 (Poor): The bead is recessed.

[0108] (Evaluation Method 2) In evaluation method 2, the circumferential welding results of Example 1-2 and Comparative Example 1-4 were evaluated focusing on the penetration of the weld.

[0109] The evaluation criteria consisted of three levels, with a rating of 4 (Excellent) being considered a passing grade. 4 (Excellent): The weld penetration is generally good. 2 (Fair): There are some defects in the penetration of the weld. 1 (Poor): The weld penetration is generally poor.

[0110] (Evaluation results) Table 1 shows the evaluation results of Evaluation Method 1-2 for the circumferential welding results of Example 1-2 and Comparative Example 1-4. Table 1 shows the gear ratio (the gear ratio when the transmission unit transmits rotational force from the handle to the head) and the head advance angle. Since Comparative Example 4 is a circumferential welding using an automatic pipe welding machine and an automatic pipe welding head, the gear ratio and head advance angle for Comparative Example 4 are not shown in Table 1.

[0111] Table 1 shows the overall evaluation results (welding results) for circumferential welding in Examples 1-2 and Comparative Examples 1-4. The evaluation criteria consisted of three levels, with a rating of 4 (Excellent) being considered a passing grade. 4 (Excellent): Passed both evaluation methods 1 and 2. 2 (Fair): In evaluation method 1-2, there was at least one evaluation of 2 (Fair) and no evaluations of 1 (Poor). 1 (Poor): In evaluation method 1-2, there was one or more evaluations of 1 (Poor).

[0112] Table 1 shows the pass (OK) or fail (NG) results for Evaluation Method 1-2 and the overall evaluation results for Example 1-2 and Comparative Example 1-4.

[0113] Figure 7 is a photograph showing the welding results of Example 1. Figure 8 is a photograph showing the welding results of Example 2. Figure 9 is a photograph showing the welding results of Comparative Example 1. Figure 10 is a photograph showing the welding results of Comparative Example 2. Figure 11 is a photograph showing the welding results of Comparative Example 3. Figure 12 is a photograph showing the welding results of Comparative Example 4 (Reference Example).

[0114] In Example 1, where circumferential welding was performed using a pipe welding machine 100 with a gear ratio of 1 / 16.3, good evaluation results were obtained in both evaluation method 1 and evaluation method 2, and the overall evaluation was also satisfactory. As shown in Figure 7, in Example 1, a weld result with evenly spaced scales was obtained, and a high-quality weld result close to the welding result of circumferential welding using an automatic pipe welding machine (reference example) (see Figure 12) was obtained.

[0115] In Example 2, circumferential welding was performed using a pipe welding machine 100 with a gear ratio of 1 / 20. Although the evaluation result in Evaluation Method 1 was inferior to that of Example 1, the result was within the acceptable range, and the overall evaluation was satisfactory. As shown in Figure 8, a slight indentation of the bead occurred in Example 2 (see the upper part of the photograph shown in Figure 8).

[0116] Comparative Example 1, which performed circumferential welding using a pipe welding machine with a gear ratio of 1 / 5, failed evaluation method 2 and also failed the overall evaluation. As shown in Figure 9, insufficient weld penetration occurred in Comparative Example 1.

[0117] Comparative Example 2, which performed circumferential welding using a pipe welding machine with a gear ratio of 1 / 10, failed evaluation method 2 and also failed the overall evaluation. As shown in Figure 10, insufficient weld penetration occurred in Comparative Example 2.

[0118] Comparative Example 3, which performed circumferential welding using a pipe welding machine with a gear ratio of 1 / 35, failed evaluation method 1 and also failed the overall evaluation. As shown in Figure 11, a depression occurred in the weld bead in Comparative Example 3 (see the top of the photograph in Figure 11).

[0119] Comparative Example 4 (Reference Example), in which circumferential welding was performed using an automatic pipe welding machine and an automatic pipe welding head, obtained good evaluation results in both evaluation method 1 and evaluation method 2, and passed the overall evaluation. However, circumferential welding using an automatic pipe welding machine and an automatic pipe welding head may require more effort to set welding conditions in advance and may increase equipment costs compared to circumferential welding using a pipe welding machine used in Examples 1-2 and Comparative Examples 1-3.

[0120] When performing circumferential welding using a pipe welding machine with a gear ratio of less than 1 / 15, as in Comparative Example 1-2, the welding speed becomes fast due to the large head advance angle. As a result, the heat input to the pipe is insufficient, leading to insufficient penetration of the material and excessively large scale openings. Consequently, good welding results cannot be obtained compared to circumferential welding using pipe welding machine 100, which has a gear ratio in the range of 1 / 15 to 1 / 20.

[0121] When the head advance angle is large, the welding speed increases, so the peak current and base current need to be increased to ensure sufficient penetration. However, even when the peak current and base current are increased, the large head advance angle may cause the scales to open too wide, potentially resulting in unsatisfactory welding results.

[0122] As in Comparative Example 3, when performing circumferential welding using a pipe welding machine with a gear ratio greater than 1 / 20, the welding speed slows down due to the small head advance angle. This results in excessive heat input to the material, causing bead depression due to over-melting of the material and collapse of the scale pattern. Consequently, good welding results cannot be obtained compared to circumferential welding using pipe welding machine 100, which has a gear ratio in the range of 1 / 15 to 1 / 20.

[0123] When the head advance angle is small, the peak current and base current must be reduced to obtain the appropriate penetration. However, even when the peak current and base current are reduced, the welding speed will be slow due to the small head advance angle, which may reduce productivity or prevent the acquisition of a good-looking scale-like weld bead. For example, the welding speed can be increased by shortening the handle operation interval by increasing the pulse frequency. However, shortening the handle operation interval increases the operating speed required of the operator, which may reduce work efficiency. For example, if the pulse frequency is 2 Hz, the operator needs to rotate the handle 45 degrees in 0.5 seconds.

[0124] Furthermore, even when using the pipe welding machine shown in Comparative Example 1-3, circumferential welding can be easily performed manually. By using the pipe welding machine 100 shown in Example 1-2, which has a gear ratio in the range of 1 / 15 to 1 / 20, circumferential welding can be easily performed manually, and good welding results can be obtained.

[0125] [Table 1] [Explanation of Symbols]

[0126] 100 Pipe Welding Machine 10 Base section 11h Base opening 14 First fixed part 20, 20A grip part 30 handle S1 Insertion space 40 heads 40h head opening 41 Receiving part 50 tablets 52 Second fixed part 60 Torch fixing part 70 Torches 80 Transmission section 81 Handle-side gear (first transmission section) 84 Head-side gear (fourth transmission section) R radial direction Z vertical direction Z1 upper Z2 downward

Claims

1. A base that can be attached to and detached from the piping, A handle is rotatably mounted on the base portion, A head is provided on the base portion so as to be rotatable along the circumferential direction of the pipe, forming an insertion space through which the pipe can be inserted. A transmission unit that transmits the rotational force input to the handle to the head, The head is provided with a torch fixing part to which a torch for welding the piping can be attached, Equipped with, The head rotates in the circumferential direction together with the torch fixing part by the rotational force transmitted from the handle via the transmission part. Pipe welding machine.

2. The head and the transmission unit have a gear structure that meshes with each other. The aforementioned transmission unit is A handle-side gear fixed to the aforementioned handle, A head-side gear that meshes with the aforementioned head, It has, The head has a transmission portion that meshes with the head-side gear, The transmission unit transmits the rotational force input to the handle to the transmitted unit with a gear ratio in the range of 1 / 15 to 1 / 20. The pipe welding machine according to claim 1.

3. The head has a head opening that opens radially in a direction intersecting the axial direction of the piping and communicates with the insertion space, The base portion has a base opening that opens downwards, When the head is in its initial position, the insertion space and the external space of the base portion are in communication through the head opening and the base opening. The pipe welding machine according to claim 1.

4. The base portion has a first fixing portion that contacts the pipe inserted into the insertion space, The locking mechanism includes a second fixing part that can be fixed between the first fixing part and the piping, The locking mechanism is provided on the base so that the second fixing part can rotate in a direction that moves closer to or further away from the piping. The pipe welding machine according to claim 1.

5. It is equipped with a gripping portion that is connected to the base portion and has a gripping shape, The handle is positioned above the head. The gripping portion is positioned above the handle. The pipe welding machine according to claim 1.

6. The gripping portion protrudes from the base portion in the axial direction of the pipe. The pipe welding machine according to claim 5.

7. Attached to the handle, and equipped with a rotation speed adjustment mechanism that maintains a constant rotation speed of the handle, The pipe welding machine according to claim 1.

8. The aforementioned handle is rotatable by a general-purpose tool. A pipe welding machine according to any one of claims 1 to 7.

9. The handle has a hexagonal shaft shape into which the tool can be fitted. The pipe welding machine according to claim 8.

10. A pipe welding method using a pipe welding machine comprising: a handle rotatably mounted on a base that can be attached to and detached from a pipe; a head rotatably mounted on the base along the circumferential direction of the pipe; a transmission unit that transmits rotational force input to the handle to the head; and a torch fixing unit to which a torch for welding the pipe can be attached, The handle is rotated, and the rotational force transmitted from the handle through the transmission unit causes the head to rotate in the circumferential direction together with the torch fixing unit. Pipe welding method.

11. The rotational force input to the handle is transmitted to the head at a gear ratio within the range of 1 / 15 to 1 / 20, thereby causing the head to rotate. The pipe welding method according to claim 10.

12. A general-purpose tool is fitted onto the handle, and the handle is rotated by the tool. The pipe welding method according to claim 10 or claim 11.

Images