Branch pipe forming apparatus and branch pipe forming method

Abstract

To provide a branch pipe formation device and a branch pipe formation method with high work efficiency.SOLUTION: A branch pipe formation device 100 mounted to an existing pipe W in order to form a branch pipe 2 communicating with a perforation port Wa formed by perforating a part of the outer peripheral surface of an existing pipe W with a perforator in a continuous flow state, comprises a first split member 3 and a second split member 4 that respectively have split surfaces 3a, 4a along a plane containing an axis X of the existing pipe W and an axis Y of the branch pipe 2, and are connected to each other by a fastening member B in a sealed state. At the connection portion between the first split member 3 and the second split member 4, connection opening parts 33, 43 facing each other via the perforation port Wa and a cutter accommodating space Sp are formed. The connection opening parts 33, 43 sandwich an end part 2A of the branch pipe 2 in the sealed state.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a branch pipe forming device and a branch pipe forming method that are attached to an existing pipe to form a branch pipe that communicates with a perforation formed by perforating a part of the outer peripheral surface of the existing pipe with a perforator in a non-stop flow state.

Background Art

[0002] The branch pipe forming device is used, for example, when renewing an existing water pipe (existing pipe) in a non-stop flow state with a newly installed water pipe. The branch pipe forming method is as follows. The branch pipe forming device is installed in a watertight state on the outer periphery of the existing water pipe, and a connecting pipe integrally formed with the branch pipe forming device is connected to the branch pipe. Then, the cutter of the perforator is inserted into a cutter accommodation space provided in the branch pipe forming device, and a part of the outer peripheral surface of the existing water pipe is perforated (half cut) to form a perforation. By making this perforation communicate with the branch pipe, it becomes possible to switch the flow path. Then, if the existing pipe between two branch pipe forming devices installed in the existing water pipe is removed, the aged section of the existing water pipe is updated to a branch pipe (newly installed water pipe).

[0003] The branch pipe forming device (connection case in the literature) described in Patent Document 1 is formed by welding together half members divided in a direction perpendicular to the plane containing the axis of the existing pipe and the axis of the branch pipe. Both flanges of a connecting pipe (cylindrical portion in the literature) integrally formed with the connection case and the branch pipe are fixed with bolts and nuts. A valve device (cylindrical case in the literature) is flange-connected to this connection case, and a working case (bottomed cylindrical case in the literature) is flange-connected to this valve device. This working case is used as a case for a perforator and a lid insertion tool for closing the connection case after perforation. Also, in the cutter accommodation space of the connection case, a cylindrical guide tube (holding member in the literature) into which the center drill of the perforator is inserted and guided is fixed by bolts screwed from below to the bottom wall of the connection case.

[0004] Patent Document 2 discloses a valve device that also functions as a conventional lid insertion tool. The valve device described in Patent Document 2 includes a valve body / lid that functions as both a valve body that blocks the flow path of the pipeline (branch pipe section in the document) and a closure lid that closes off the pipeline. When fixing this valve body / lid as a closure lid, a bolt is inserted from below into a through hole in the flange of the branch pipe section, and a nut is inserted from above into an insertion hole in the top plate of the housing body of the valve device, and the bolt and nut are screwed together. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 60-201808 [Patent Document 2] Japanese Patent Publication No. 2018-123963 [Overview of the project] [Problems that the invention aims to solve]

[0006] The branch pipe forming apparatus described in Patent Document 1 suffers from reduced work efficiency because the split members are joined by welding. Furthermore, the branch pipes connected to the branch pipe forming apparatus are subjected to bending and tensile forces due to earthquakes, etc., which could lead to water leakage from the flange connection portion between the connecting pipe and the branch pipe in the connection case, as well as from the welded portion of the split member.

[0007] Therefore, there is a need for a branch pipe forming apparatus and a branch pipe forming method that offer high work efficiency. [Means for solving the problem]

[0008] The characteristic configuration of the branch pipe forming apparatus according to the present invention is a branch pipe forming apparatus that is attached to an existing pipe in order to form a branch pipe that communicates with a perforation opening formed by perforating a part of the outer surface of the existing pipe with a perforating machine in a non-stop flow state, and a first dividing member having a cut surface along a plane that includes the axis of the existing pipe and the axis of the branch pipe, and connected to each other by fastening members in a sealed state. and, Second divided member The assembly includes a cylindrical guide tube into which the center drill of the drilling machine is inserted and guided, and a flat plate member placed on the bottom of the second divided member and connected to the guide tube,The first divided member has a cylindrical portion having an opening through which the cutter of the drilling machine can pass, a cutter housing space is formed between the first divided member and the second divided member at a position adjacent to the drilling opening formed in a direction perpendicular to the plane, the axis of the cylindrical portion is located on the side of the branch pipe rather than the outer surface of the existing pipe in the cutter housing space, a connecting opening is formed at the connection portion between the first divided member and the second divided member, facing the drilling opening and the cutter housing space, and the connecting opening clamps the end of the branch pipe in a sealed state. Furthermore, the bottom of the second divided member has a receiving recess for accommodating the flat plate member, and an engaging recess or engaging projection in the center of the receiving recess into which the end of the guide tube engages. It's at a single point.

[0009] In this configuration, the first and second dividing members constituting the branch pipe forming device are sealed and connected by a cut surface that aligns with the plane containing the axis of the existing pipe and the axis of the branch pipe. Therefore, for example, it is possible to mount the first dividing member on top of the second dividing member with the second dividing member positioned vertically downwards, allowing the cutter housing space inside the second dividing member to be visible and enabling the first dividing member to be connected to the second dividing member by operating the fastening member from above. As a result, it is possible to improve work efficiency when replacing existing pipes.

[0010] Furthermore, since the end of the branch pipe is held in a sealed state at the connecting opening between the first and second divided members, even if bending or tensile forces are applied to the branch pipe due to an earthquake or the like, the branch pipe can flexibly move slightly, reducing the load on the connecting opening. Moreover, since a cylindrical section with an opening through which the cutter can pass is formed in the first divided member, and the cut surfaces (connecting surfaces) of both divided members are aligned with a plane that includes the axis of the existing pipe and the axis of the branch pipe, the vibration of the drilling machine does not directly act on the cut surface compared to when the cut surface (connecting surface) is perpendicular to this plane, resulting in less misalignment of the cutter axis during drilling. Since the axis of this cylindrical section is located on the side of the branch pipe rather than the outer surface of the existing pipe in the cutter housing space, the perforation opening drilled by the cutter can be made to have a cross-sectional area of ​​less than half the existing pipe, thus maintaining the strength of the existing pipe. In this way, we have been able to provide a branch pipe forming device with high work efficiency and excellent seismic performance.

[0011] Another characteristic feature is that the cutter housing space accommodates a cutter with a diameter smaller than the outer diameter of the existing pipe.

[0012] This configuration makes it possible to make the cutter housing space more compact, thus enabling the miniaturization of the branch pipe forming device.

[0013] The branch pipe forming apparatus according to the present invention The feature configuration is, A branch pipe forming device attached to an existing pipe to form a branch pipe that communicates with a perforation opening formed by perforating a portion of the outer surface of the existing pipe with a drilling machine in a continuous flow state, comprising: a first dividing member having a split surface along a plane including the axis of the existing pipe and the axis of the branch pipe, and connected to each other in a sealed state by a fastening member; a second dividing member; and a cylindrical guide cylinder into which the center drill of the drilling machine is inserted and guided, wherein the first dividing member has a cylindrical portion having an opening through which the cutter of the drilling machine can pass, and between the first dividing member and the second dividing member, there is a front formed in a direction perpendicular to the plane. A cutter housing space capable of housing the cutter is formed adjacent to the perforation opening, the axis of the cylindrical portion is located on the side of the branch pipe rather than the outer circumferential surface of the existing pipe in the cutter housing space, a connecting opening is formed at the connection portion between the first divided member and the second divided member, facing the perforation opening and the cutter housing space, the connecting opening clamps the end of the branch pipe in a sealed state, the guide tube extends from the second divided member toward the opening rather than the cut surface, and a bolt is screwed into the guide tube that abuts the lower vertical side of the outer circumferential surface of the existing pipe. It's at a single point.

[0014] As in this configuration, if the guide tube extends beyond the cut surface to the side of the opening through which the cutter passes, the center drill will be guided more reliably, eliminating misalignment of the cutter axis and allowing for the formation of a drilled hole with high precision.

[0015] Another characteristic feature is that it further includes a cylindrical guide tube into which the center drill of the drilling machine is inserted and guided, and the axis of the guide tube is perpendicular to the cut surface.

[0016] As in this configuration, if the axis of the guide cylinder is perpendicular to the cut surface, the vibration of the drilling machine is less likely to directly act on the cut surface, resulting in less misalignment of the cutter axis during drilling.

[0018] As in this configuration, by providing a receiving recess for accommodating a flat plate member in the second divided member, and providing an engaging recess or engaging projection in the center of this receiving recess for engaging the end of the guide tube, the positioning of the guide tube is easy, misalignment of the cutter axis is eliminated, and a drilled hole can be formed with high precision. Moreover, since the end of the guide tube is engaged by the receiving recess provided in the second divided member, there is no need to screw a bolt into the second divided member from below to fix the guide tube, resulting in high work efficiency.

[0019] Another characteristic feature is that the flat plate member is composed of multiple divided plates.

[0020] If the flat plate member is composed of dividing plates as in this configuration, it becomes possible to sequentially install the dividing plates while visually recognizing the cutter accommodation space with the second dividing member arranged on the lower side in the vertical direction, improving the working efficiency.

[0021] Another characteristic configuration lies in that an annular convex portion protruding toward the side of the perforation hole is formed on the outer edge portion of the flat plate member.

[0022] If an annular convex portion protruding toward the side of the perforation hole is provided on the outer edge portion of the flat plate member as in this configuration, it becomes possible to accommodate the chips generated when forming the perforation hole in the existing pipe in the inner space of the annular convex portion, thus preventing the chips from flowing out into the existing pipe or the branch pipe. Moreover, since it is only necessary to provide the annular convex portion on the outer edge portion of the flat plate member, the manufacturing cost can be reduced.

[0023] Another characteristic configuration is that a protruding portion protruding radially outward and connected to the flat plate member is formed at the end of the guide cylinder, and an engaging member that can engage with an annular recess formed on the outer peripheral surface of the center drill and a biasing member that biases the engaging member radially inward toward the annular recess are accommodated inside the protruding portion.

[0024] If an engaging member and a biasing member are provided inside the protruding portion for connecting the flat plate member and the guide cylinder as in this configuration, it becomes possible to engage the engaging member with the center drill and simultaneously recover the guide cylinder and the flat plate member when removing the drilling machine. Moreover, since the engaging member and the biasing member are accommodated inside the protruding portion, it becomes possible to shorten the axial length of the guide cylinder, thus enabling miniaturization of the branch pipe forming device.

[0025] Another characteristic configuration is that a tapered surface capable of abutting against the tip of the center drill is formed on the engaging member, and when the tip of the center drill abuts against the tapered surface, the engaging member moves radially outward against the biasing force of the biasing member.

[0026] As shown in this configuration, by providing a tapered surface on the engaging member, the guide tube and flat plate member can be engaged with the drilling machine simply by inserting the center drill into the guide tube, thereby increasing work efficiency.

[0028] As in this configuration, by screwing a bolt that abuts the lower vertical side of the outer surface of the existing pipe into the guide tube, the position of the guide tube remains stable even when subjected to vibrations from the drilling machine, and misalignment of the cutter axis can be reliably prevented.

[0029] The characteristic configuration of the branch pipe forming apparatus according to the present invention is a branch pipe forming apparatus that is attached to an existing pipe in order to form a branch pipe that communicates with a perforation opening formed by perforating a part of the outer surface of the existing pipe with a perforating machine in a non-stop flow state, and comprises a first divided member and a second divided member connected to each other by a fastening member in a sealed state, a cutter housing space formed between the first divided member and the second divided member at a position adjacent to the perforation opening and capable of housing the cutter of the perforating machine, the cutter has a cylindrical hole saw with a cutting tip at its tip, a disc-shaped vibration damping member that absorbs vibrations is inserted into the hole saw, and an elastic member that abuts against the inner surface of the hole saw is fixed to the outer end face of the vibration damping member.

[0030] As in this configuration, if an elastic member is fixed to the outer peripheral end face of the vibration damping member inserted into the hole saw, and contacts the inner peripheral surface of the hole saw, this elastic member absorbs the vibration of the hole saw, thereby suppressing the wobble of the hole saw and enabling quick and smooth drilling. Thus, this results in a branch pipe forming device with high work efficiency.

[0031] Another characteristic feature is that the elastic member is divided into multiple parts so as not to overlap with the cutting tip when viewed in the direction of the rotation axis of the hole saw.

[0032] As in this configuration, if the elastic members are divided and arranged in positions that do not overlap with the cutting chips, the vibration damping members can be inserted into the hole saw without damaging the elastic members.

[0033] Another feature of the configuration is that it further includes a mounting jig for attaching a corrosion-preventive member to the perforation opening, and the mounting jig has an expandable and contractible mechanism that allows the corrosion-preventive member to be pressed against the perforation opening from the axial direction of the branch pipe and to be detached from the corrosion-preventive member.

[0034] As in this configuration, if the mounting jig for attaching the corrosion-preventive member to the perforation port has an expandable / contractible mechanism, it becomes possible to press the corrosion-preventive member against the perforation port from the axial direction of the branch pipe by utilizing the connecting opening opposite the perforation port, thereby ensuring that the corrosion-preventive member is securely attached. Furthermore, by using this expandable / contractible mechanism to detach the mounting jig from the corrosion-preventive member and retrieve it, the mounting jig will not obstruct the flow path of the branch pipe.

[0035] Another characteristic feature of the corrosion protection member is that it includes an annular corrosion protection seal that conforms to the shape of the perforation opening, and an expanding member that expands the diameter of the annular corrosion protection seal by having a tapered surface that contacts the inner circumferential surface of the annular corrosion protection seal.

[0036] As in this configuration, if the corrosion protection member includes an expanding member that expands the diameter of the annular corrosion protection seal, the annular corrosion protection seal can be reliably made to adhere tightly to the hole.

[0037] The branch pipe formation method according to the present invention is characterized by being a branch pipe formation method using any of the branch pipe formation apparatuses described above, and includes a division member arrangement step of arranging the first division member and the second division member in the existing pipe; a division member connection step of clamping the end of the branch pipe between the first division member and the second division member and connecting the first division member and the second division member in a sealed state with a fastening member; a drilling machine attachment step of attaching the drilling machine to the first division member; a branch flow path closure step of closing the gate valve provided in the branch pipe; and a drilling opening formation step of moving the cutter into the cutter housing space and forming the drilling opening at a position adjacent to the cutter housing space. This results in a branch pipe formation method with high work efficiency.

[0038] The branch pipe formation method according to the present invention is characterized by forming a branch pipe that communicates with a perforation opening formed by perforating a part of the outer surface of an existing pipe with a perforating machine in a state of continuous flow, and includes a division member arrangement step of arranging the first division member and the second division member on the existing pipe such that the cut surface of the first division member and the cut surface of the second division member are aligned with a plane that includes the axis of the existing pipe and the axis of the branch pipe; a division member connection step of connecting the first division member and the second division member in a sealed state by fastening member by clamping the end of the branch pipe in the connecting opening between the first division member and the second division member; a perforation machine mounting step of attaching the perforating machine to the first division member; a branch flow path closure step of closing a gate valve provided in the branch pipe; and a perforation opening formation step of moving the cutter of the perforating machine into a cutter housing space formed between the first division member and the second division member to form the perforation opening at a position adjacent to the cutter housing space.

[0039] In this method, the first and second dividing members constituting the branch pipe forming device are sealed and connected by a cut surface that aligns with the plane containing the axis of the existing pipe and the axis of the branch pipe. Therefore, for example, it is possible to mount the first dividing member on top of the second dividing member with the second dividing member positioned vertically downwards, allowing the cutter housing space inside the second dividing member to be visible and enabling the first dividing member to be connected to the second dividing member by operating the fastening member from above. As a result, it is possible to improve work efficiency when replacing existing pipes.

[0040] Furthermore, since the end of the branch pipe is held in a sealed state at the connecting opening between the first and second divided members, even if bending or tensile forces are applied to the branch pipe due to an earthquake or the like, the branch pipe can move flexibly and slightly, reducing the load on the connecting opening. Moreover, since a gate valve is provided on the branch pipe held at the connecting opening, and the gate valve is closed to block the branch flow path before forming the perforation, it is possible to independently create multiple perforations in the existing pipe, resulting in high work efficiency. In this way, we have been able to provide a branch pipe formation method that is highly efficient and has excellent seismic resistance. [Brief explanation of the drawing]

[0041] [Figure 1] This is an overall perspective view of the branch pipe forming apparatus. [Figure 2] This is a cross-sectional perspective view of the branch pipe forming device, cut vertically. [Figure 3] This is a plan view showing a water pipe with a branch pipe forming device attached. [Figure 4] This is a diagram showing the first divided member. [Figure 5] This is a diagram showing the second divided member. [Figure 6] This is an exploded perspective view showing the process of arranging the divided components. [Figure 7] This is a perspective view showing the process of connecting the divided members. [Figure 8] This is a cross-sectional view of a branch pipe forming device with an attachment. [Figure 9] This is a perspective view showing the attachment mounting process. [Figure 10] This is a cross-sectional perspective view of a branch pipe forming apparatus, showing the drilling process, cut vertically. [Figure 11] This is an enlarged cross-sectional view showing the drilling process. [Figure 12] This is a cross-sectional view showing the drilling process. [Figure 13] This is a plan view showing the valve closing process. [Figure 14] This is a side view showing the valve closing process. [Figure 15] This is a cross-sectional view showing the valve closing process. [Figure 16] This is a perspective view showing the lid fixing process. [Figure 17] This is a cross-sectional perspective view of the branch pipe forming device after the removal of the work equipment, cut vertically. [Figure 18] This is a perspective view showing the process of fixing the side wall pieces. [Figure 19] This is an enlarged cross-sectional view showing the lid in its fixed position. [Figure 20] This is a plan view showing a water pipe with a branch pipe forming device attached. [Figure 21]This is a plan view showing a water pipe with a branch pipe forming device attached. [Figure 22] This is a side view of a branch pipe forming apparatus according to another embodiment 1. [Figure 23] This is a cross-sectional view showing a drilling process using a branch pipe forming apparatus according to another embodiment 2. [Figure 24] This is a cross-sectional view showing a valve closing process using a valve cover according to another embodiment 3. [Figure 25] This is a cross-sectional view showing a branch pipe attached to the branch pipe forming apparatus according to another embodiment 4. [Figure 26] This is a plan view of the second divided member showing the branch pipe attached to the branch pipe forming apparatus according to another embodiment 4. [Figure 27] This is a cross-sectional view showing a branch pipe attached to the branch pipe forming apparatus according to another embodiment 5. [Figure 28] This is a cross-sectional view showing a branch pipe forming apparatus according to another embodiment 6 with a drilling machine attached. [Figure 29] This is a cross-sectional view showing the drilling process according to another embodiment 6. [Figure 30] This is a perspective view showing a cutter and vibration damping member according to another embodiment 6. [Figure 31] This is a cross-sectional view showing the state before the corrosion-preventive member is attached to the perforation opening using the branch pipe forming apparatus according to another embodiment 7. [Figure 32] This is a cross-sectional view showing the state in which a corrosion-preventive member is attached to the perforation opening using the branch pipe forming apparatus according to another embodiment 7. [Figure 33] This is a cross-sectional view showing the state after a corrosion-preventive member has been attached to the perforation opening using the branch pipe forming apparatus according to another embodiment 7. [Figure 34] This is an exploded perspective view showing a corrosion-preventive member according to another embodiment 7. [Figure 35] This is a diagram showing an annular corrosion protection seal according to another embodiment 7. [Figure 36] This is a cross-sectional view showing the sealing test process according to another embodiment 8. [Figure 37] This is a cross-sectional view showing the valve body mounting process according to another embodiment 8. [Figure 38] This is an enlarged perspective view showing a valve operating member according to another embodiment 8. [Figure 39] This is a cross-sectional view showing the lid replacement process according to another embodiment 9. [Modes for carrying out the invention]

[0042] Embodiments of the branch pipe forming apparatus and branch pipe forming method according to the present invention will be described below with reference to the drawings. In this embodiment, as an example of a branch pipe forming apparatus and branch pipe forming method, a branch pipe forming apparatus 100 that is attached to a water pipe W (an example of an existing pipe) that constitutes a fluid piping system during replacement and seismic reinforcement work, and a branch pipe forming method using the branch pipe forming apparatus 100 will be described. However, the invention is not limited to the following embodiments, and various modifications are possible without departing from the gist of the invention.

[0043] As shown in Figures 1 and 2, the branch pipe forming device 100 is composed of a split T-shaped pipe with a divided structure that is attached to a water pipe W (an example of an existing pipe) to form a branch pipe 2 that communicates with a perforation opening Wa formed by perforating a part of the outer surface of the water pipe W (an example of an existing pipe) with a perforation machine 1 in a non-stop flow state. The branch pipe forming device 100 comprises a first divided member 3 and a second divided member 4 that have split surfaces 3a and 4a along a plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2, and are connected to each other in a sealed state by a fastening member B, and a lid 5 (an example of a lid that also serves as a valve) that closes the opening 31a (end) of the cylindrical portion 31 (an example of a pipeline) of the first divided member 3. Here, "split surfaces 3a and 4a along a plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2" means that the split surfaces 3a and 4a are on a plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2, or on a plane substantially parallel to said plane. In this embodiment, the water pipe W, branch pipe 2, and branch pipe forming apparatus 100 are formed using the same type of material, such as cast iron pipe or steel pipe. Since an opening 31a is formed in the first divided member, casting is easier compared to the case where the opening is formed across the first divided member 3 and the second divided member 4. Note that the water pipe W and the branch pipe 2 or branch pipe forming apparatus 100 may be formed using different materials.

[0044] In this embodiment, the branch pipe forming apparatus 100 is mounted along the outer surface of the water pipe W such that the first dividing member 3 is positioned vertically upward and the second dividing member 4 is positioned vertically downward. The first dividing surface 3a of the first dividing member 3 and the second dividing surface 4a of the second dividing member 4 are aligned along a horizontal plane parallel to the ground. Hereafter, the direction of gravity may be described as downward and the opposite direction as upward.

[0045] As shown in Figures 2 and 3, the end flange 2A of the branch pipe 2 is sandwiched between the connecting openings 33 and 43 of the first divided member 3 and the second divided member 4. In this embodiment, the branch pipe 2 has both flanges 21a and 22a of the connecting pipe 22 having a gate valve V connected by bolts 23 and nuts 24. Another connecting pipe is connected to the flange 22b of the connecting pipe 22 opposite to flange 22a.

[0046] As shown in Figures 4 and 6, the first divided member 3 is composed of a half-split member and has a semi-cylindrical first main body portion 32 that follows the outer surface of the water pipe W, a semi-cylindrical first connecting opening 33 that extends from the first main body portion 32 toward the branch pipe 2 and follows the outer surface of the branch pipe 2, and a cylindrical tubular portion 31 that extends upward across the first main body portion 32 and the first connecting opening 33.

[0047] The first main body portion 32 has a first curved portion 32a that curves along the outer surface of the water pipe W, and a first flange portion 32b that protrudes laterally from the first curved portion 32a to the water pipe W. In the first curved portion 32a, a pair of through holes 32a1 are formed on diagonal lines that intersect with the axis X of the water pipe W in a plan view. Position-fixing bolts 38, whose tips abut against the outer surface of the water pipe W, are inserted into this pair of through holes 32a1 and screwed into nuts 39 housed in an anti-rotation state on the inner surface of the first main body portion 32 (see also Figure 6). By the contact of these position-fixing bolts 38 with the outer surface of the water pipe W, the first divided member 3 is fixed in position on the water pipe W so as not to rotate. In addition, a bolt Ba constituting the fastening member B is inserted into the first flange portion 32b, and a plurality of first through holes 32b1 (four in this embodiment) are formed along the axis X, into which nuts Bb that the bolt Ba screws onto are located (see also Figure 1).

[0048] The first connecting opening 33 has a first branch curved portion 33a that curves along the outer circumferential surface of the end flange 2A of the branch pipe 2, and a pair of first branch flange portions 33b that protrude from the first branch curved portion 33a along the axis X of the water pipe W. A bolt Ba constituting the fastening member B is inserted into this pair of first branch flange portions 33b, and a plurality of first through holes 33b1 are formed (two in each first branch flange portion 33b in this embodiment) into which nuts Bb that the bolt Ba is screwed (see also Figure 1).

[0049] A rectangular first split surface 3a is formed on the outer edge of the inner surface of the first flange portion 32b and the first connecting opening 33 of the first main body portion 32. A rectangular first seal groove 3a1 is formed across this first split surface 3a and the inner surface of the first curved portion 32a, into which the first seal member S1 is fitted. The first seal member S1 adheres tightly to the outer surface of the water pipe W and the outer surface of the end flange 2A of the branch pipe 2, thereby sealing the first split member 3 to the water pipe W and the branch pipe 2.

[0050] The cylindrical portion 31 has an opening 31a through which the hole saw 11 (an example of a cutter) of the drilling machine 1 can pass, and a base end portion 31b connected to the first main body portion 32 and the first connecting opening 33. The axis Z of the cylindrical portion 31 coincides with the rotation axis of the hole saw 11, is located on the side of the branch pipe 2 than the axis X of the water pipe W, and does not overlap with the water pipe W in a plan view (see also Figures 8 and 12). In other words, the axis Z of the cylindrical portion 31 is located on the side of the branch pipe 2 than the outer surface of the water pipe W in the cutter housing space Sp. As a result, the perforation opening Wa drilled by the hole saw 11 has a cross-sectional area of ​​less than half the width of the water pipe W, and the strength of the water pipe W can be maintained. An annular recess 31a1 (an example of the outer surface of the end portion) is formed in the opening 31a, which the tip of the contact bolt T described later will contact (see also Figure 2). The base end portion 31b has multiple columnar portions 31c (four in this embodiment, arranged at equal intervals in the circumferential direction) that protrude radially outward, each having a hole 31c1 into which an embedded bolt U for fixing the attachment 7 (described later) is screwed. The top surfaces of these multiple columnar portions 31c constitute a seating surface 31c2 on which the attachment 7 is placed, and these seating surfaces 31c2 are arranged on the same plane to maintain the horizontal orientation of the attachment 7.

[0051] As shown in Figures 5 and 6, the second divided member 4 is composed of a half-split member and has a semi-cylindrical second main body portion 42 that follows the outer surface of the water pipe W, a semi-cylindrical second connecting opening 43 that extends from the second main body portion 42 toward the branch pipe 2 and follows the outer surface of the branch pipe 2, and a bottom portion 41 that spans the second main body portion 42 and the second connecting opening 43 and is recessed in a circular shape in plan view downwards when viewed from the inner side.

[0052] The second main body portion 42 has a second curved portion 42a that curves along the outer surface of the water pipe W, and a second flange portion 42b that protrudes laterally from the second curved portion 42a to the water pipe W. In the second curved portion 42a, a pair of through holes 42a1 are formed on diagonal lines that intersect with the axis X of the water pipe W in a plan view. Position-fixing bolts 38, whose tips abut against the outer surface of the water pipe W, are inserted into this pair of through holes 42a1, similar to the first divided member 3, and are screwed into nuts 39 that are housed on the inner surface of the second main body portion 42 in an anti-rotation state. By abutting the outer surface of the water pipe W with these position-fixing bolts 38, the second divided member 4 is fixed in position to the water pipe W so that it does not rotate. In addition, the second flange portion 42b has a plurality (four in this embodiment) of second through holes 42b1 formed along the axis X into which bolts Ba constituting the fastening member B are inserted.

[0053] The second connecting opening 43 has a second branch curved portion 43a that curves along the outer circumferential surface of the end flange 2A of the branch pipe 2, and a pair of second branch flange portions 43b that protrude from the second branch curved portion 43a along the axis X of the water pipe W. Multiple second through holes 43b1 (two in each second branch flange portion 43b in this embodiment) are formed in this pair of second branch flange portions 43b into which bolts Ba constituting the fastening member B are inserted.

[0054] A rectangular second split surface 4a is formed on the outer edge of the inner surface of the second flange portion 42b and the second connecting opening 43 of the second main body portion 42. A rectangular second seal groove 4a1 is formed across this second split surface 4a and the inner surface of the second curved portion 42a, into which the second seal member S2 is fitted. The second seal member S2 adheres tightly to the outer surface of the water pipe W and the outer surface of the end flange 2A of the branch pipe 2, thereby sealing the second divided member 4 to the water pipe W and the branch pipe 2. In addition, the first seal member S1 fitted into the first seal groove 3a1 of the first split surface 3a and the second seal member S2 fitted into the second seal groove 4a1 of the second split surface 4a are pressed against each other, sealing the gap between the first divided member 3 and the second divided member 4.

[0055] The bottom portion 41 has a circular receiving recess 41a in plan view for accommodating the flat plate member 9 described later, and a circular engaging recess 41b in plan view in the center of the receiving recess 41a into which the end of the guide tube 8 described later engages (see also Figure 8). The receiving recess 41a is formed by recessing the bottom portion 41 downwards, and the engaging recess 41b is formed by recessing the center of the receiving recess 41a further downwards. In addition, the receiving recess 41a has an annular projection 41c in plan view that protrudes upwards on the outer circumference adjacent to the engaging recess 41b, and the upper surface of this annular projection 41c is a mounting surface 41c1 on which the projection 82 of the guide tube 8 described later is placed (see also Figure 11). This mounting surface 41c1 is a plane parallel to the plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2. In this configuration, an annular groove 41d is formed on the outer circumference of the annular protrusion 41c, and the flat plate member 9 is placed in this annular groove 41d.

[0056] As shown in Figures 1 and 2, the lid 5 that closes the opening 31a of the cylindrical portion 31 of the first divided member 3 has a bottom wall 51 and a side wall 52 that rises from the outer edge of the bottom wall 51. This lid 5 functions as a valve body that blocks the flow path of the cylindrical portion 31 as a pipeline, and also functions as a closing lid that closes the cylindrical portion 31. Hereinafter, the valve body 6 that houses the lid 5 may be referred to as the "valve body combined lid".

[0057] The bottom wall 51 is a flat plate member with a circular shape in plan view, and an arc-shaped elongated groove 51a (an example of an engaging portion) that can engage with the valve operating member Vk is formed on its outer surface (see also Figures 13 to 14). By rotating the end of the valve operating member Vk from one end to the other of the elongated groove 51a, the cover 5 slides inside the valve body 6. As a result, it is possible to switch between a closed valve state in which the cover 5 closes the opening of the cylindrical portion 31 and an open valve state in which the cover 5 moves away from the opening of the cylindrical portion 31. In addition, a number of through holes 51b (two in this embodiment) are formed on the outer edge of the bottom wall 51 on the side opposite to the elongated groove 51a, into which fixing bolts K for fixing the side wall piece 53, which will be described later, are inserted. Furthermore, an annular seal groove 51c is formed on the inner surface of the outer edge of the bottom wall 51, into which an annular seal member S3 is fitted. When this annular seal member S3 is in close contact with the upper surface of the opening 31a of the cylindrical portion 31, the lid 5 seals the cylindrical portion 31 of the first divided member 3. Note that the bottom wall 51 is not limited to a circular shape in plan view, but may be configured in a rectangular shape in plan view, for example.

[0058] The side wall 52 is provided on a part of the outer edge of the bottom wall 51 and consists of a protruding portion that integrally protrudes over a region of the bottom wall 51 that is more than a semicircle (more than 180 degrees). Side wall pieces 53 are attached to the outer edge of the bottom wall 51 where the side wall 52 is not present.

[0059] The side wall 52 has two screw holes 52a on each side, opposite to each other along the axis X of the water pipe W, into which a plurality of (four in this embodiment) contact bolts T are screwed, which abut against an annular recess 31a1 formed on the outer circumferential surface of the opening 31a of the cylindrical portion 31. In this embodiment, the contact bolts T are made of hexagon socket head bolts, and by screwing the contact bolts T into these screw holes 52a, the tips of the contact bolts T bite into the annular recess 31a1, fixing the lid 5 to the cylindrical portion 31 of the first divided member 3 (see also Figure 19). Alternatively, the annular recess 31a1 may be omitted, and the contact bolts T may be brought into contact with the smooth outer circumferential surface of the opening 31a of the cylindrical portion 31.

[0060] The side wall piece 53 is made up of an arc-shaped member and is inserted into the outer edge of the bottom wall 51 where the side wall 52 does not exist. The side wall piece 53 has a first screw hole 53a that penetrates horizontally along the axis X of the water pipe W and into which a contact bolt T is screwed, and a plurality of second screw holes 53b (two in this embodiment) that penetrate perpendicular to the axis X of the water pipe W and the axis Y of the branch pipe 2 and into which fixing bolts K are screwed (see also Figure 18). The side wall piece 53 inserted into the outer edge of the bottom wall 51 where the side wall 52 does not exist is integrated with the lid 5 by inserting the fixing bolt K through the through hole 51b of the bottom wall 51 and screwing it into the second screw hole 53b, and by screwing the contact bolt T into the first screw hole 53a, the tip of the contact bolt T bites into the annular recess 31a1 and is fixed to the cylindrical portion 31 of the first divided member 3 (see also Figure 19). The first screw hole 53a into which the contact bolt T is screwed may be omitted.

[0061] Next, the working equipment used in the branch pipe formation method using the branch pipe formation device 100 will be described. As shown in Figure 12, the working equipment used in this embodiment includes a drilling machine 1, a valve body 6 that houses a lid 5 which functions as a valve body that blocks the flow path of the cylindrical portion 31, an attachment 7 for stably fixing the valve body 6, a guide tube 8 that guides the center drill 12 of the drilling machine 1, and a flat plate member 9 connected to the guide tube 8. Hereinafter, the drilling machine 1, valve body 6, attachment 7, guide tube 8, and flat plate member 9 may be referred to collectively as the branch pipe formation device 100.

[0062] As shown in Figures 11 and 12, the drilling machine 1 comprises a cylindrical hole saw 11 (an example of a cutter) having a cutting tip 11a, a center drill 12 that protrudes outward from the center of the hole saw 11 beyond the cutting tip 11a, a rotational drive mechanism 13 including a motor that rotates the hole saw 11 and the center drill 12, and a drilling case 14 that houses the hole saw 11 and the center drill 12. Alternatively, the rotational drive mechanism 13 may rotate only the hole saw 11, while the center drill 12 remains stationary.

[0063] In this embodiment, the hole saw 11 has an outer diameter smaller than the outer diameter of the water pipe W, and cuts a portion of the outer surface of the water pipe W. The hole saw 11 and the center drill 12 are connected to the rotating shaft 13a of the rotary drive mechanism 13, and move back and forth in a direction perpendicular to the plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2 while rotating. When the rotary drive mechanism 13 rotates the hole saw 11 toward the water pipe W and moves it forward in the downward direction, the cutting tip 11a of the hole saw 11 cuts a portion of the outer surface (side) of the water pipe W, forming a perforation Wa along this perpendicular direction (see also Figure 2). The perforation Wa, which is aligned perpendicular to the plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2, has a shape that matches the outer shape of the hole saw 11, and in plan view it is formed in a semi-circular arc along the axis X of the water pipe W. Note that the outer diameter of the hole saw 11 may be greater than or equal to the outer diameter of the water pipe W.

[0064] When the hole saw 11 and center drill 12 are moved forward by the rotational drive mechanism 13, a cutter housing space Sp capable of accommodating the hole saw 11 is formed between the first divided member 3 and the second divided member 4 at a position adjacent to the drilling opening Wa. In this configuration, connecting openings 33 and 43 are formed at the connection portion between the first divided member 3 and the second divided member 4, facing each other via the drilling opening Wa and the cutter housing space Sp, and these connecting openings 33 and 43 clamp the end flange 2A of the branch pipe 2 in a sealed state. In this embodiment, the center drill 12 has tapered corners along the entire circumferential direction of the tip surface of the tip portion 12a, and an annular recess 12a1 is formed on the side surface of the tip portion 12a.

[0065] As shown in Figures 12 to 14, the valve body 6 has a valve body main body 61 that houses the cover 5, and a valve body cylindrical portion 62 that extends cylindrically from the valve body main body 61 and through which the hole saw 11 and center drill 12 can pass. The valve body main body 61 has a cover housing portion 61A that houses the cover 5 in the open state, and a valve body fixing portion 61B that houses the cover 5 in the closed state and is fixed to the attachment 7. At the end of the valve body cylindrical portion 62, a valve body flange 62a is formed to protrude in an annular shape and is fixed to the drilling flange 14a of the drilling case 14 of the drilling machine 1 with bolts and nuts.

[0066] The lid housing section 61A is a rectangular box in plan view, and a valve operating member Vk is fixed to the upper wall in a sealed state. By rotating the operating lever Vk1, the end of the valve operating member Vk rotates from one end to the other of the long groove 51a, causing the lid 5 to slide inside the valve box 6.

[0067] The valve body fixing portion 61B has a circular valve body cylindrical portion 63 in plan view that, together with the lid housing portion 61A, forms a movable space for the lid 5, and a valve body extension portion 64 that extends from the valve body cylindrical portion 63 along the outer circumferential surface of the attachment 7. The valve body cylindrical portion 63 is provided with a plurality of (four in this embodiment) operating through holes 63a into which an operating tool (not shown) for screwing in a contact bolt T, which is a socket head cap screw for fixing the lid 5 to the cylindrical portion 31 of the first divided member 3, is inserted. Closing bolts 63a1 are screwed into these operating through holes 63a, which close in a watertight manner except when the operating tool is inserted. In addition, the upper wall of the valve body cylindrical portion 63 is provided with a plurality of (two in this embodiment) through holes 63b for press bolts into which a press bolt P that presses against the outer edge of the lid 5 that closes the opening 31a of the cylindrical portion 31 is screwed. The valve body extension 64 is provided with multiple (four in this embodiment) valve fixing through holes 64a into which valve body fixing bolts 65 that abut against the lower part of the attachment 7 are screwed. In addition, an annular projection 64b is formed on the inner circumferential surface of the valve body extension 64 at the boundary with the valve body cylindrical portion 63. The attachment 7 is sandwiched between this annular projection 64b and the valve body fixing bolts 65, thereby fixing the valve body 6 to the attachment 7.

[0068] As shown in Figures 8 and 9, the attachment 7 is composed of an annular member that surrounds the outer circumferential surface of the cylindrical portion 31 of the first divided member 3. In this embodiment, the attachment 7 has a divided structure composed of a pair of semicircular members, and each semicircular member has multiple fixing through holes 71 along the vertical direction (two holes in each semicircular member in this embodiment) into which embedded bolts U for fixing the attachment 7 to the first divided member 3 are inserted. The attachment 7 is fixed to the first divided member 3 by inserting the embedded bolts U into these fixing through holes 71 and screwing the embedded bolts U into the holes 31c1 of the columnar portion 31c of the first divided member 3. In this embodiment, the head of the embedded bolt U is provided with an annular seal groove Ua, and an O-ring Ub is fitted into this seal groove Ua. In addition, annular tapered surfaces 72 are formed on the upper and lower outer edges of the outer circumferential surface of the attachment 7. The tip of the valve body fixing bolt 65 abuts against the lower annular tapered surface 72, causing the annular projection 64b of the valve body 6 and the valve body fixing bolt 65 to sandwich the attachment 7, thereby fixing the valve body 6 to the attachment 7 (see also Figure 12). Note that the attachment 7 is not limited to an annular member, and may be configured, for example, as a polygonal shape in plan view.

[0069] As shown in Figures 10 to 12, the guide tube 8 guides the vertical movement of the center drill 12 of the drilling machine 1 into which the center drill 12 is inserted. The guide tube 8 has a cylindrical circumferential wall portion 81 having an inner diameter approximately the same as the outer diameter of the center drill 12, and an annular projection portion 82 that protrudes radially outward from the end of the circumferential wall portion 81 and is connected to the flat plate member 9. The end of the circumferential wall portion 81 engages with an engagement recess 41b formed in the bottom portion 41 of the second divided member 4, thereby positioning the guide tube 8. The upper end of the circumferential wall portion 81 of the guide tube 8 protrudes above the cut surfaces 3a and 4a and is located on the side of the opening 31a of the cylindrical portion 31. In other words, the guide tube 8 extends from the second divided member 4 to the side of the opening 31a of the cylindrical portion 31, beyond the cut surfaces 3a and 4a. This ensures reliable guidance of the center drill 12, eliminates misalignment of the cutter axis, and allows for the precise formation of the drilled hole Wa. Furthermore, the axis of the peripheral wall portion 81 of the guide cylinder 8 coincides with the axis Z of the cylindrical portion 31 and is perpendicular to the cut surfaces 3a and 4a. As a result, vibrations of the drilling machine 1 are less likely to directly act on the cut surfaces 3a and 4a, and cutter axis misalignment during drilling is reduced. Note that the guide cylinder 8 can have any shape as long as it can guide the vertical movement of the center drill 12.

[0070] The peripheral wall portion 81 has a through-hole 81a that holds the cut portion Wb, which is separated from the water pipe W when a perforation opening Wa is formed in the water pipe W. The cut portion Wb is sandwiched between this through-hole 81a and the inner surface of the hole saw 11, thereby holding the cut portion Wb. In addition, a pair of block portions 83 are formed protruding from both sides of the peripheral wall portion 81 along the axis X of the water pipe W, into which an axis-holding bolt J is screwed, which abuts against the lower vertical side of the outer surface of the water pipe W (cut portion Wb) to prevent the drilling machine 1 from shifting its axis. Since this axis-holding bolt J abuts against the lower vertical side of the outer surface of the water pipe W (cut portion Wb), it also has the function of preventing the cut portion Wb from falling. The form of the axis-holding member that prevents the drilling machine 1 from shifting its axis is not particularly limited, and may be composed of an axis-holding pin instead of an axis-holding bolt J.

[0071] The protruding portion 82 has a plurality of bolt insertion holes 82a (four in this embodiment) formed on its outer circumference, into which outer circumference fixing bolts G are inserted to fix it to the flat plate member 9. Inside these bolt insertion holes 82a, a holding mechanism 84 is provided to hold the center drill 12 of the drilling machine 1. The holding mechanism 84 has a housing box 82b formed in the protruding portion 82, an engaging member 84a that can engage with an annular recess 12a1 formed on the outer circumference surface of the center drill 12, and a compression coil spring 84b (an example of a biasing member) that biases the engaging member 84a radially inward toward the annular recess 12a1. Alternatively, the outer circumference fixing bolts G may be made of pins, and the protruding portion 82 and the flat plate member 9 may be pin-fitted.

[0072] The housing box 82b is integrally formed on the upper surface of the protrusion 82 and is a pair of box-shaped members having an opening radially inward. The compression coil spring 84b and the engaging member 84a are inserted and housed in this opening in that order. The engaging member 84a is made up of a rectangular parallelepiped block-shaped member, and a tapered surface 84a1 is formed on the upper surface of its tip, which can contact the tapered tip corner formed on the tip surface of the tip portion 12a of the center drill 12. When the tip corner of the center drill 12 contacts the tapered surface 84a1, the engaging member 84a moves radially outward against the biasing force of the compression coil spring 84b. When the center drill 12 is moved further forward, the engaging member 84a engages with the annular recess 12a1 due to the biasing force of the compression coil spring 84b, and the center drill 12 is held by the holding mechanism 84.

[0073] The flat plate member 9 is formed in an annular shape in plan view and is connected to the guide tube 8 while resting in an annular groove 41d formed in the receiving recess 41a of the second divided member 4. The flat plate member 9 has multiple (four in this embodiment) outer peripheral fixing bolt screw holes 91 into which outer peripheral fixing bolts G for fixing the guide tube 8 to the flat plate member 9 are screwed. In addition, an annular projection 92 is formed on the outer edge of the flat plate member 9, protruding toward the perforation opening Wa. This annular projection 92 is made of an elastic material such as rubber that is fixed to the upper surface of the flat plate member 9 by adhesive or the like, but it may also be integrally formed with the flat plate member 9. Note that the flat plate member 9 is not limited to an annular shape in plan view, and may be configured in a rectangular shape in plan view, for example.

[0074] In this embodiment, the flat plate member 9 is made of a single, integrally formed member, but it is preferable to make it of a plurality (for example, two) divided plates. By making the flat plate member 9 of divided plates, when inserting it into the receiving recess 41a of the second divided member 4, one divided plate can be placed in the annular groove 41d so as not to interfere with the water pipe W, and then rotated to the underside of the water pipe W, thereby allowing the other divided plate to be placed in the annular groove 41d so as not to interfere with the water pipe W. On the other hand, if the flat plate member 9 is made of a single member, the flat plate member 9 will be inserted into the receiving recess 41a of the second divided member 4 at an angle.

[0075] Next, a method for forming a branch pipe using the branch pipe forming device 100 will be explained with reference to Figures 6 to 19. In this embodiment, the branch pipe forming device 100 is attached to a predetermined part of the water pipe W to form a branch pipe 2 that communicates with the water pipe W. Then, other branch pipe forming devices 100 are attached to other parts of the water pipe W to form branch pipes 2 that communicate with the water pipe W. The aging water pipe W located between these branch pipe forming devices 100 is removed, and the water pipe W is replaced with branch pipes 2 (new water pipes W).

[0076] The branch pipe formation method in this embodiment includes (1) a divided member arrangement step shown in Figure 6, (2) a divided member connection step shown in Figure 7, (3) an attachment mounting step shown in Figures 8 to 9, (4) a drilling step shown in Figures 10 to 12, (5) a valve closing step shown in Figures 13 to 15, (6) a lid fixing step shown in Figure 16, (7) a valve body removal step shown in Figure 17, and (8) a side wall piece mounting step shown in Figures 18 to 19.

[0077] (1) Process of arranging divided members As shown in Figure 6, the first divided member 3 and the second divided member 4 are positioned on the water pipe W such that the cut surface 3a of the first divided member 3 and the cut surface 4a of the second divided member 4 are aligned with a plane that includes the axis X of the water pipe W and the axis Y of the branch pipe 2.

[0078] Specifically, first, the second divided member 4, with the second sealing member S2 fitted into the second sealing groove 4a1, is placed on the underside of the water pipe W, and the end flange 2A of the branch pipe 2 is placed in the second connecting opening 43 of the second divided member 4. If there is a support that can maintain the second divided member 4 in a horizontal position, the process of storing the flat plate member 9 and the guide tube 8 in the cutter housing space Sp described later in (2) divided member connection step may be performed.

[0079] With the water pipe W and branch pipe 2 (including the flat plate member 9 and guide tube 8 if there is a support base for the second divided member 4) positioned above the second divided member 4, the first divided member 3 (see Figure 4), with the first seal member S1 fitted into the first seal groove 3a1, is brought close to the second divided member 4 from above, so that the cut surface 3a of the first divided member 3 and the cut surface 4a of the second divided member 4 face each other. In this way, since the first divided member 3 and the second divided member 4 that constitute the branch pipe forming device 100 are composed of cut surfaces 3a and 4a that are aligned with a plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2, it is easy to mount the first divided member 3 on top of the second divided member 4 with the second divided member 4 positioned vertically below it.

[0080] (2) Process of connecting divided members As shown in Figures 6 and 7, the end flange 2A of the branch pipe 2 is clamped in the connecting openings 33 and 43 between the first divided member 3 and the second divided member 4, and the first divided member 3 and the second divided member 4 are connected in a sealed state by fastening members B. These fastening members B are placed in a total of eight locations: four on the first flange portion 32b of the first divided member 3 and the second flange portion 42b of the second divided member 4, and four on the first branch flange portion 33b of the first divided member 3 and the second branch flange portion 43b of the second divided member 4. Through the fastening operation with these fastening members B, the first seal member S1 fitted into the first seal groove 3a1 of the first split surface 3a and the second seal member S2 fitted into the second seal groove 4a1 of the second split surface 4a are pressed against each other, thereby sealing the gap between the first divided member 3 and the second divided member 4 and creating a sealed state with respect to the water pipe W and the branch pipe 2 (see also Figure 8). Then, position fixing bolts 38 are inserted into the pair of through holes 32a1 of the first divided member 3 and the pair of through holes 42a1 of the second divided member 4 to fix the first divided member 3 and the second divided member 4 in position on the water pipe W so that they do not rotate.

[0081] Next, as shown in Figure 6, the flat plate member 9 and the guide tube 8 are housed in the cutter housing space Sp through the opening 31a of the cylindrical portion 31 of the first divided member 3 or the opening of the branch pipe 2. Specifically, the flat plate member 9 is placed in the annular groove 41d of the housing recess 41a of the second divided member 4, and this flat plate member 9 is connected to the guide tube 8 by the outer peripheral fixing bolt G (see also Figure 11). Next, the axis holding bolt J, which has been pre-inserted into the block portion 83 of the guide tube 8, is tightened so that the tip of the axis holding bolt J contacts the lower vertical side of the outer peripheral surface of the water pipe W (cut portion Wb) (see also Figure 12). The operation of connecting the flat plate member 9 and the guide tube 8 with the outer peripheral fixing bolt G and tightening the axis holding bolt J can be performed from above while looking into the cutter housing space Sp, and furthermore, positioning the guide tube 8 is easy as it only requires engaging the end of the guide tube 8 with the engagement recess 41b formed in the center of the housing recess 41a. Furthermore, when placing the flat plate member 9, if the flat plate member 9 is made up of divided plates, when inserting it into the receiving recess 41a of the second divided member 4, one divided plate can be placed in the annular groove 41d so as not to interfere with the water pipe W, and then rotated to the underside of the water pipe W, thereby allowing the other divided plate to be placed in the annular groove 41d so as not to interfere with the water pipe W.

[0082] In this embodiment, the first dividing member 3 and the second dividing member 4 constituting the branch pipe forming device 100 are composed of split surfaces 3a and 4a along a plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2. Therefore, it is possible to connect the first dividing member 3 to the second dividing member 4 by operating the fastening member B from above, thereby increasing work efficiency. In other words, bolt tightening work on the lower side of the water pipe W and the branch pipe 2 is unnecessary. Furthermore, since the end flange 2A of the branch pipe 2 is held in a sealed state between the connecting openings 33 and 43 of the first dividing member 3 and the second dividing member 4, even if bending or tensile forces are applied to the branch pipe 2 due to an earthquake or the like, the load can be absorbed by the first dividing member 3 and the second dividing member 4, reducing the load on the fastening member B. Also, even if bending or tensile forces are applied to the branch pipe 2 due to an earthquake or the like, the branch pipe 2 can move flexibly in small increments, reducing the load on the connecting openings 33 and 43. In particular, since the first dividing member 3 and the second dividing member 4 constituting the branch pipe forming device 100 are composed of cutting surfaces 3a and 4a along a plane that includes the axis X of the water pipe W and the axis Y of the branch pipe 2, there are no vertical joints, and the strength against loads (tensile forces) in the direction of the axis Y of the branch pipe 2 is high. As a result, the branch pipe forming device 100 has excellent seismic performance.

[0083] (3) Attachment mounting process As shown in Figures 8 and 9, the two-part attachment 7 is placed on the seating surfaces 31c2 of the multiple columnar portions 31c formed on the cylindrical portion 31 of the first divided member 3, and the embedded bolts U inserted into the fixing through holes 71 of the attachment 7 are screwed into the holes 31c1 of the columnar portions 31c. Since these seating surfaces 31c2 are arranged on the same plane to maintain the horizontal position of the attachment 7, the fixing work of the attachment 7 to the first divided member 3 is easy. Moreover, since the first divided member 3 and the second divided member 4 that constitute the branch pipe forming device 100 are composed of split surfaces 3a and 4a that are aligned with the plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2, the attachment 7 can be fixed by operating the embedded bolts U from above.

[0084] (4)Drilling process As shown in Figures 10 to 12, the drilling process includes a drilling machine mounting step of attaching the drilling machine 1 to the first divided member 3, a branch flow path closure step (see Figure 3) of closing the gate valve V provided in the branch pipe 2, and a hole formation step of moving the hole saw 11 of the drilling machine 1 into the cutter housing space Sp formed between the first divided member 3 and the second divided member 4 to form a drilled hole Wa at a position adjacent to the cutter housing space Sp.

[0085] In the drilling machine mounting process, the valve body 6 is fixed to the attachment 7 (first divided member 3), and the drilling machine 1 is mounted on the valve body 6. When fixing the valve body 6 to the attachment 7, the valve body fixing bolt 65 is screwed into the valve fixing through hole 64a of the valve body extension 64 of the valve body 6, and the tip of the valve body fixing bolt 65 is brought into contact with the annular tapered surface 72 on the lower side of the attachment 7. As a result, the annular projection 64b of the valve body 6 and the valve body fixing bolt 65 sandwich the attachment 7, and the valve body 6 is fixed to the attachment 7. Then, the valve body flange 62a of the valve body cylindrical portion 62 and the drilling flange 14a of the drilling case 14 of the drilling machine 1 are fixed with bolts and nuts, and the drilling machine 1 is mounted on the first divided member 3 via the valve body 6.

[0086] In the branch channel closure process, the gate valve V installed in the branch pipe 2 is closed to prevent the flow path from being changed from the water pipe W to the branch pipe 2 through the perforation Wa formed in the subsequent perforation port formation process (see Figure 3). In this way, a gate valve V is installed in the branch pipe 2, which is sandwiched between the connecting openings 33 and 43, and the perforation port Wa is formed after the gate valve V is closed to block the branch channel of the branch pipe 2. This makes it possible to perform piping work downstream of the gate valve V in advance. In other words, it is possible to form the perforation port Wa in the water pipe W at any time without interfering with piping work, resulting in high work efficiency.

[0087] In the hole formation process, the rotary drive mechanism 13 rotates the hole saw 11 and the center drill 12 and moves them forward downward. As the center drill 12 is inserted into the guide tube 8, the cutting tip 11a of the hole saw 11 cuts a portion (side) of the outer surface of the water pipe W, forming a hole Wa. The cut portion Wb created by the formation of this hole Wa is held between the outer wall through hole 81a formed in the outer wall portion 81 of the guide tube 8 and the inner surface of the hole saw 11. At this time, the axis holding bolt J is in contact with the lower vertical side of the outer surface of the water pipe W (cut portion Wb), thus preventing misalignment of the drilling machine 1 and reliably preventing the cut portion Wb from falling. Furthermore, a cylindrical portion 31 is formed in the first divided member 3, which has an opening through which the hole saw 11 can pass. Since the cut surfaces 3a and 4a of the first divided member 3 and the second divided member 4 are aligned with a plane containing the axis X of the water pipe W and the axis Y of the branch pipe 2, the vibration of the drilling machine 1 does not directly act on the cut surfaces 3a and 4a compared to the case where the cut surfaces 3a and 4a are perpendicular to this plane, resulting in less misalignment of the cutter axis during drilling. Moreover, in this embodiment, an annular projection 92 is formed on the outer edge of the flat plate member 9, so that chips can be contained in the inner space of the annular projection 92, thereby preventing chips from flowing out into the water pipe W or branch pipe 2.

[0088] Even after the hole Wa is formed, when the rotation drive mechanism 13 advances the hole saw 11 and center drill 12 downwards, the tip corner of the center drill 12 comes into contact with the tapered surface 84a1 of the engaging member 84a, causing the engaging member 84a to move radially outward against the biasing force of the compression coil spring 84b. Then, when the rotation drive mechanism 13 advances the hole saw 11 and center drill 12 further downwards, the biasing force of the compression coil spring 84b causes the engaging member 84a to engage with the annular recess 12a1, and the center drill 12 is held by the holding mechanism 84 of the guide cylinder 8. In this state, when the rotation drive mechanism 13 retracts the hole saw 11 and center drill 12 upwards, the flat plate member 9 placed in the annular groove 41d formed in the housing recess 41a of the second divided member 4, and the guide cylinder 8 fixed to this flat plate member 9, move upward together with the center drill 12. As a result, the drilling machine 1, the flat plate member 9, and the guide tube 8 can be moved together with the cutting portion Wb to a position above the lid 5 housed in the valve box 6.

[0089] (5) Valve closing process As shown in Figures 13 to 15, the valve closing process involves moving the lid 5 housed in the valve body 6 to the cylindrical portion 31 of the first divided member 3, thereby closing the opening of the cylindrical portion 31. Specifically, first, the end of the valve operating member Vk rotates from one end to the other of the long groove 51a, causing the lid 5 to slide inside the valve body 6, and the portion of the bottom wall 51 without a side wall 52 passes through the opening 31a of the cylindrical portion 31. By providing a portion of the bottom wall 51 without a side wall 52, it becomes possible to pass this portion through the opening 31a of the cylindrical portion 31, allowing the lid 5, which acts as the valve body, to slide using the valve operating member Vk. Next, the outer edge of the lid 5 is pressed by a press bolt P screwed into a press bolt through hole 63b of the valve body fixing portion 61B. As a result, the annular sealing member S3 provided on the inner surface of the outer edge of the bottom wall 51 of the lid 5 adheres tightly to the upper surface of the opening 31a of the cylindrical portion 31, thereby sealing the cylindrical portion 31 of the first divided member 3 with the lid 5. Consequently, the insides of the first divided member 3 and the second divided member 4 are sealed, making it possible to remove the drilling machine 1.

[0090] In this embodiment, a drilling machine removal step is provided between (5) the valve closing step and (6) the lid fixing step. In the drilling machine removal step, the outer edge of the lid 5 is pressed with a push bolt P to seal the inside of the first divided member 3 and the second divided member 4, and then the drilling machine 1, the flat plate member 9 and the guide tube 8 are removed together with the cut portion Wb (see Figure 12). That is, after moving the drilling machine 1, the flat plate member 9 and the guide tube 8 together with the cut portion Wb to a position above the lid 5, the bolts and nuts that were fixing the drilling flange 14a of the drilling case 14 and the valve body flange 62a are removed, and the drilling machine 1, the flat plate member 9 and the guide tube 8 are removed together with the cut portion Wb. As a result, as shown in Figure 15, the valve body 6 and the attachment 7 remain as working equipment. The drilling machine removal step may also be performed in the valve body removal step described later in (7) the valve body removal step.

[0091] (6) Lid fixing process As shown in Figure 16, the lid fixing process involves inserting the tip of the contact bolt T into the annular recess 31a1 of the cylindrical portion 31 of the first divided member 3 to fix the lid 5 to the cylindrical portion 31 (see also Figure 19). Specifically, the closing bolt 63a1 of the operating through hole 63a is removed, an operating tool (not shown) is inserted, and this operating tool is operated from outside the valve body 6 to screw the contact bolt T, which is a socket head cap screw, into the screw hole 52a formed in the side wall 52 of the lid 5 (see also Figure 19). Then, the tip of the contact bolt T is inserted into the annular recess 31a1, and the lid 5 is fixed to the cylindrical portion 31 of the first divided member 3. Alternatively, the contact bolt T may be pre-threaded into the side wall 52 of the lid 5 and then fully threaded using an operating tool, or the contact bolt T may be attached to the tip of the operating tool and inserted into the operating through hole 63a, and the contact bolt T may be threaded into the threaded hole 52a formed in the side wall 52 of the lid 5. In this way, when fixing the lid 5, which functions as a closing lid, to the cylindrical portion 31, it is only necessary to operate the contact bolt T from the outside and thread it into the threaded hole 52a, resulting in extremely high work efficiency.

[0092] (7) Valve box removal process As shown in Figure 17, the valve body removal process involves removing the valve body 6, which is fixed to the attachment 7 fixed to the first divided member 3, leaving the branch pipe forming device 100 including the attachment 7. Specifically, the valve body fixing bolts 65 that fixed the valve body 6 to the attachment 7 are removed (see also Figure 12). At this time, the gap between the first divided member 3 and the second divided member 4 is sealed by the (2) divided member connection process, so that the branch pipe forming device 100 is sealed to the water pipe W and the branch pipe 2, and the lid 5 fixed to the cylindrical portion 31 in the (6) lid fixing process closes the inside of the first divided member 3 and the second divided member 4, so that no water leaks to the outside of the branch pipe forming device 100.

[0093] (8) Side wall piece installation process As shown in Figures 18 to 19, the side wall piece installation step involves attaching the side wall piece 53 to the outer edge of the bottom wall 51 of the lid 5 where the side wall 52 does not exist. In the side wall piece installation step, it is preferable to remove the attachment 7 after installing the side wall piece 53, rather than removing the attachment 7 in the (7) valve body removal step. This allows the side wall piece 53 to be inserted into the lid 5 along the upper surface of the attachment 7.

[0094] After inserting the side wall piece 53 into the outer edge of the bottom wall 51 of the lid 5 where the side wall 52 does not exist, the fixing bolt K is inserted through the through hole 51b of the bottom wall 51 and screwed into the second screw hole 53b, thereby integrating the side wall piece 53 with the lid 5. Then, by screwing the abutment bolt T into the first screw hole 53a, the tip of the abutment bolt T bites into the annular recess 31a1, fixing the side wall piece 53 to the cylindrical portion 31 of the first divided member 3. Next, the embedded bolt U that was fixing the attachment 7 to the columnar portion 31c of the first divided member 3 is removed, and the attachment 7 of the divided structure is removed in order. In this way, by providing the side wall piece 53 which is attached to the outer edge of the bottom wall 51 where the side wall 52 does not exist, the fixed position of the lid 5 as a sealing lid is stabilized. Furthermore, by inserting the fixing bolt K into the through hole 51b of the bottom wall 51 and fixing the side wall piece 53, the lid 5 as a sealing lid can be firmly fixed. Furthermore, by providing through holes 51b in the bottom wall 51, it becomes possible to operate the fixing bolts K from above, thereby improving work efficiency.

[0095] [Other embodiments] In the following, other embodiments will be described only for configurations that differ from the branch pipe forming apparatus 100 according to the above-described embodiment. For ease of understanding, configurations similar to those of the branch pipe forming apparatus 100 according to the above-described embodiment will be described using the same component names and reference numerals.

[0096] (1) In the above-described embodiment, the end of the peripheral wall portion 81 of the guide tube 8 is engaged with the engaging recess 41b formed in the bottom portion 41 of the second divided member 4. Alternatively, a recess may be provided at the end of the peripheral wall portion 81 of the guide tube 8, and a protrusion (engaging protrusion) may be provided in the bottom portion 41 of the second divided member 4, and these recesses and protrusions may be engaged. (2) In the above-described embodiment, a long groove 51a is provided on the outer surface of the bottom wall 51 of the lid 5, into which the end of the valve operating member Vk engages, and the lid 5 is slid by the valve operating member Vk. However, the tip of the pusher member may be engaged with an engagement groove provided on the side wall 52 of the lid 5, and the lid 5 may be slid by the pusher member.

[0097] (3) As shown in Figure 20, the end flange 2A of the branch pipe 2 is sandwiched between the connecting openings 33 and 43 of the first divided member 3 and the second divided member 4. In this embodiment, the branch pipe 2 omits the short pipe 21 in the above-described embodiment and has an end flange 2A at the end of the connecting pipe 22 which has a gate valve V. Another connecting pipe (not shown) is connected to the flange 22b on the opposite side of the end flange 2A of the connecting pipe 22. (4) As shown in Figure 21, the branch pipe 2 is composed of a bent pipe having a pipe joint 28, and the end flange 2A of the branch pipe 2 is sandwiched between the connecting openings 33 and 43 of the first divided member 3 and the second divided member 4. In this embodiment, the branch pipe 2 is connected to a short pipe 21 and a connecting pipe 22 having a gate valve V by a pipe joint 28. Another connecting pipe is connected to the flange 22b of the connecting pipe 22 on the opposite side of the pipe joint 28. (5) The existing pipe in the above-described embodiment is not limited to the water pipe W, but may be other fluid pipes.

[0098] (6) Figure 22 shows a side view of a branch pipe forming device 100A according to another embodiment 1. In the embodiment described above, the branch pipe forming device 100 was fixed in position to the water pipe W by a position fixing bolt 38 whose tip abuts against the outer surface of the water pipe W, so as not to rotate. Alternatively, as shown in Figure 22, a plurality of anti-rotation protrusions 32a2, 42a2 (six in this embodiment) may be provided on the inner surfaces of the first curved portion 32a of the first divided member 3 and the second curved portion 42a of the second divided member 4. It is preferable that these anti-rotation protrusions 32a2, 42a2 are provided at equal intervals along the outer surface of the water pipe W. These anti-rotation protrusions 32a2, 42a2 may be rib-shaped protrusions integrally extending from the inner surfaces of the first curved portion 32a and the second curved portion 42a, or they may be separate members such as wedges or screws fixed to concave grooves on the inner surfaces of the first curved portion 32a and the second curved portion 42a.

[0099] (7) Figure 23 shows a cross-sectional view illustrating a drilling process using a branch pipe forming apparatus 100B according to another embodiment 2. In the branch pipe forming apparatus 100 according to the above embodiment, a guide tube 8 is provided to guide the center drill 12 of the drilling machine 1. Alternatively, as shown in Figure 23, the center drill 12 of the drilling machine 1 may be omitted, and the rotation axis of the hole saw 11 may be positioned tangentially to the outer circumference of the water pipe W. In addition, instead of the guide tube 8 and the flat plate member 9 connected to the guide tube 8, a cutter guide member 10 positioned inside the hole saw 11 and a flat plate member 10a integrally formed at one end (tip) of the cutter guide member 10 may be provided. A curved recess 10b along the outer circumference of the water pipe W is formed in the middle portion of the cutter guide member 10, and an annular flange 10c is formed at the other end (base end) of the cutter guide member 10. Furthermore, an engaging member 11b is formed on the inside of the hole saw 11, protruding in an annular shape inward, and an engaged portion 10c1 is formed on the annular flange 10c that can be diametrically engaged with the engaging member 11b. The engaged portion 10c1 may be a locking ring fitted into the annular flange 10c, or it may be a block-shaped member biased by an elastic member such as a spring. As the hole saw 11 rotates and moves downward, the inclined surface 11b1 of the engaging member 11b comes into contact with the inclined surface 10c2 of the engaged portion 10c1, causing the engaged portion 10c1 to move radially inward. As a result, after the hole saw 11 passes through the annular flange 10c, the engaged portion 10c1 moves radially outward, and the engaging member 11b and the engaged portion 10c1 engage. The flat plate member 10a has the same shape as the flat plate member 9 described above, so a detailed explanation is omitted. In this embodiment, by omitting the center drill 12 of the drilling machine 1, the hole saw 11 can be moved closer to the water pipe W, and cutting can be performed with an opening width equal to the cutter diameter of the hole saw 11. In other words, the cutter diameter of the hole saw 11 can be reduced, and the cutter housing space Sp can be reduced, making the branch pipe forming device 100B more compact.

[0100] In the segmented member connection process, the cutter guide member 10 is housed in the cutter housing space Sp through the opening 31a of the cylindrical portion 31 of the first segmented member 3 or the opening of the branch pipe 2. The cutter guide member 10 may be configured as a segmented body to facilitate housing in the cutter housing space Sp. In the hole formation process, as the hole saw 11 is rotated by the rotary drive mechanism 13 and advanced downwards, the hole saw 11 is fitted onto the cutter guide member 10, and a part of the outer surface (side) of the water pipe W is cut by the cutting tip 11a of the hole saw 11, forming a hole Wa. At this time, the engagement portion 10c1 comes into contact with the inner surface of the hole saw 11, suppressing the vibration of the hole saw 11. The cut portion Wb generated by the formation of this hole Wa is held between the curved recess 10b of the cutter guide member 10 and the inner surface of the hole saw 11. Even after the hole Wa is formed, when the hole saw 11 is advanced downward by the rotary drive mechanism 13, the engaging member 11b and the engaged portion 10c1 of the hole saw 11 engage, and the hole saw 11 is held by the cutter guide member 10. In this state, when the hole saw 11 is retracted upward by the rotary drive mechanism 13, the cutter guide member 10, which holds the cutting portion Wb, moves upward together with the hole saw 11.

[0101] (8) Figure 24 shows a cross-sectional view illustrating a valve closing process using a lid 5A according to another embodiment 3. In the embodiment described above, the lid 5 that closes the opening 31a of the cylindrical portion 31 of the first divided member 3 had a bottom wall 51 and a side wall 52 that rises from the outer edge of the bottom wall 51. Alternatively, as shown in Figure 24, the lid 5A may be made of a flat plate member 54 that is circular in plan view and does not have a side wall 52. In this embodiment, the attachment 7 functions as a detachable flange, and the lid 5A is fixed to this attachment 7 by a lid fastening member 73 made of bolts or the like. This lid 5A functions as a valve body that blocks the flow path of the cylindrical portion 31 as a pipeline, and also functions as a closing lid that closes the cylindrical portion 31. In this embodiment, by making the first divided member 3 and the attachment 7 separate, it is not necessary to provide a flange integrally formed with the first divided member 3 to fix the lid 5A, and manufacturing costs can be reduced.

[0102] (9) Figures 25 and 26 show a cross-sectional view and a plan view of the second dividing member 4, respectively, showing the branch pipe 2 attached to the branch pipe forming apparatus 100C according to another embodiment 4. In this embodiment, the branch pipe forming apparatus 100C has contact protrusions 34 and 44 formed on the connecting openings 33 and 43 of the first dividing member 3 and the second dividing member 4, which abut against the end flange 2A to prevent the branch pipe 2 from moving into the cutter housing space Sp. These contact protrusions 34 and 44 are formed from curved members that protrude inward along the end flange 2A from a pair of side walls of the connecting openings 33 and 43, and are configured not to obstruct the flow of water in the branch channel of the branch pipe 2. In this embodiment, since the connecting openings 33 and 43 firmly clamp the end flange 2A of the branch pipe 2 in a sealed state, even if bending or pressing forces are applied to the branch pipe 2 due to an earthquake or the like, it is possible to prevent the branch pipe 2 from entering the cutter housing space Sp.

[0103] (10) Figure 27 shows a cross-sectional view of the branch pipe forming apparatus 100D according to another embodiment 5 with the branch pipe 2 attached. In the embodiment described above, the end flange 2A of the branch pipe 2 was housed inside the connecting openings 33 and 43 (on the cutter housing space Sp side). Alternatively, as shown in Figure 27, the branch pipe 2 may be inserted into the connecting openings 33 and 43, with the end flange 2A of the branch pipe 2 positioned outside the connecting openings 33 and 43, and a pair of fixing members 35 and 45 for fixing the end flange 2A may be attached to the pair of connecting openings 33 and 43. In this embodiment, the branch pipe 2 can be attached and detached without disassembling the branch pipe forming apparatus 100D.

[0104] (11) Figures 28 to 30 show a branch pipe forming device 100E and a vibration damping member 15 according to another embodiment 6. As described above, the hole saw 11 is formed in a cylindrical shape including a cutting tip 11a at its tip. The hole saw 11 according to this embodiment has a disc-shaped vibration damping member 15 that absorbs vibrations inserted inside, and an elastic member 15a that abuts against the inner surface of the hole saw 11 is fixed to the outer peripheral end face of the vibration damping member 15.

[0105] As shown in Figure 28, in the branch pipe forming apparatus 100E according to this embodiment, a pair of block portions 83 (a total of four) are formed protruding from both sides of the peripheral wall portion 81A of the guide cylinder 8A along the axis X of the water pipe W. These block portions abut against the upper and lower vertical sides of the outer circumferential surface of the water pipe W (cut portion Wb), respectively, and into which axis-holding bolts J that prevent misalignment of the drilling machine 1 are screwed. In addition, in this embodiment, a guide projection 81Aa is formed protruding circumferentially from the inner surface of the upper vertical side of the peripheral wall portion 81A of the guide cylinder 8A, guiding along the tapered shape of the tip portion 12a of the center drill 12.

[0106] As shown in Figure 30, the vibration damping member 15 has a disc-shaped body 15b made of the same material as the hole saw 11, and a plurality (four in this embodiment) of elastic members 15a made of rubber, resin, etc., fixed to the outer surface of the disc-shaped body 15b. A through hole 15c is formed in the center of the disc-shaped body 15b, and the vibration damping member 15 is inserted into the hole saw 11 by inserting a center drill 12 that does not have a cutter function into this through hole 15c. The disc-shaped body 15b is supported by the center drill 12 that does not have a cutter function, so that the vibration damping member 15 does not shift position due to vibration. The plurality of elastic members 15a are divided into multiple parts so as not to overlap with the cutting tip 11a when viewed in the direction of the rotation axis of the hole saw 11. Therefore, when inserting the vibration damping member 15 into the hole saw 11, it is possible to prevent the elastic members 15a from coming into contact with and damaging the cutting tip 11a. As described above, an elastic member 15a is fixed to the outer peripheral end face of the vibration damping member 15 inserted into the hole saw 11, so that it contacts the inner peripheral surface of the hole saw 11, and this elastic member 15a absorbs the vibration of the hole saw 11. In addition, the hole saw 11 has multiple fluid passage holes 11c formed through it in a staggered pattern to allow fluid ejected during drilling to pass through. The elastic member 15a may be provided over the entire outer circumference of the disc-shaped body 15b, or an elastic member may be provided between the through holes 15c and the center drill 12, or multiple weight-reducing holes may be provided in the disc-shaped body 15b. Furthermore, the shape of each cutting tip 11a in the hole saw 11 may be a partially protruding shape as shown in Figure 30, or it may be a shape that slopes along the circumferential direction with a pointed cutting portion.

[0107] As shown in Figure 29, in the drilling process, the hole opening formation step involves moving the hole saw 11 of the drilling machine 1 into the cutter housing space Sp formed between the first dividing member 3 and the second dividing member 4, thereby forming a hole opening Wa adjacent to the cutter housing space Sp. At this time, the central portion (peripheral portion of the through hole 15c) of the vibration damping member 15 inserted into the hole saw 11 abuts against the upper end of the guide cylinder 8A, and as the hole saw 11 moves downward, the vibration damping member 15 rises inside the hole saw 11. In this embodiment, an elastic member 15a that abuts against the inner circumferential surface of the hole saw 11 is fixed to the outer peripheral end surface of the vibration damping member 15, so that this elastic member 15a slides smoothly up the inner circumferential surface of the hole saw 11. Furthermore, this elastic member 15a prevents the hole saw 11 from vibrating without the disc-shaped body 15b of the vibration damping member 15 amplifying the vibration of the hole saw 11. Furthermore, since the central part of the disc-shaped body 15b abuts against the upper end of the guide tube 8A, the movement posture of the vibration damping member 15 is stabilized, and vibration of the hole saw 11 can be reliably prevented. As a result, drilling work can be performed quickly and smoothly. Although the disc-shaped body 15b is set inside the hole saw 11 as shown in Figure 28, it may also be set at the upper end of the guide tube 8A. In other words, when drilling the water pipe W with the hole saw 11, it is sufficient for the disc-shaped body 15b to be inside the hole saw 11.

[0108] (12) Figures 31 to 35 show a branch pipe forming apparatus 100F and a corrosion-resistant member 93 according to another embodiment 7. The branch pipe forming apparatus 100F in this embodiment further includes a mounting jig 46 for mounting the corrosion-resistant member 93 to the perforation port Wa. This mounting jig 46 has an expandable mechanism 46A that can press the corrosion-resistant member 93 against the perforation port Wa from the axis Y direction of the branch pipe 2 and can detach from the corrosion-resistant member 93, and a jig case 46B that is connected to the valve body 6 and houses the expandable mechanism 46A in a sealed state.

[0109] The telescopic mechanism 46A includes an operating rod 46a with a male thread formed on its outer circumference, a pair of movable blocks 46b that are screwed onto the operating rod 46a and can move up and down, a link member 46c fixed to one end of the movable block 46b so as to expand or contract in diameter when the upper movable block 46b moves down or up, and expand or contract in diameter when the lower movable block 46b moves up or down, a cylindrical holding member 46d that holds the corrosion-resistant member 93, and a pair of contact blocks 46e that can contact the end flange 2A of the branch pipe 2. The pair of holding members 46d and the contact blocks 46e are fixed to the other end of the link member 46c so as to move in conjunction with the expansion or contraction of the link member 46c.

[0110] As shown in Figure 34, the corrosion protection member 93 includes an annular corrosion protection seal 93A having an end face that conforms to the shape of the perforation opening Wa, and an expansion member 93B that expands the diameter of the annular corrosion protection seal 93A by a tapered surface 93Ba1 that abuts against the inner circumferential surface of the annular corrosion protection seal 93A. The annular corrosion protection seal 93A is made of an elastically deformable material such as rubber that expands in diameter with the expansion member 93B, and has a cylindrical portion 93Aa with a contact portion 93Aa1 formed at its tip that adheres to the inner circumferential surface of the perforation opening Wa, and a sealing portion 93Ab that protrudes outward in an annular shape from the cylindrical portion 93Aa and abuts against and seals the perforation opening Wa. The expansion member 93B has an annular base portion 93Bb that abuts against the flange 46d1 of the retaining member 46d, and a protruding cylindrical portion 93Ba that is inserted along the inner circumferential surface of the cylindrical portion 93Aa and protrudes from the annular base portion 93Bb. The protruding cylindrical portion 93Ba has a tapered surface 93Ba1 that expands in diameter as it is inserted along the inner circumferential surface of the cylindrical portion 93Aa, and the tip portion 93Ba2 has a side-view arc shape that conforms to the shape of the perforation port Wa and the contact portion 93Aa1. In this way, if the corrosion protection member 93 includes an expanding member 93B that expands the diameter of the annular corrosion protection seal 93A, the annular corrosion protection seal 93A can be reliably made to adhere tightly to the perforation port Wa.

[0111] As shown in the front view of Figure 35, the annular corrosion-preventive seal 93A has a tapered surface on the inner circumferential surface of the contact portion 93Aa1 that becomes thinner towards the tip. This tapered surface allows the contact portion 93Aa1 to conform to the shape of the inner circumferential surface of the water pipe W when it is in close contact with the perforation opening Wa, thereby reducing flow resistance (see Figure 33). Furthermore, as shown in the rear view of Figure 35, the annular corrosion-preventive seal 93A has an inner circumferential surface of the cylindrical portion 93Aa that is not inclined and is formed parallel to the axis Y of the branch pipe 2 so that it forms a single inner circle when viewed from the rear. As a result, when the expansion member 93B is inserted into the cylindrical portion 93Aa, the cylindrical portion 93Aa expands evenly along the tapered surface 93Ba1 of the expansion member 93B. Furthermore, as shown in the plan view and side view of Figure 35, the annular corrosion protection seal 93A has an adhesive portion 93Aa1 and a sealing portion 93Ab that are formed in an arc shape that is convex in plan view and concave in side view. As a result, the adhesive portion 93Aa1 and the sealing portion 93Ab are shaped to conform to the shape of the perforation port Wa, ensuring reliable corrosion protection of the perforation port Wa.

[0112] The corrosion protection member mounting step, in which the corrosion protection member 93 is mounted to the perforation opening Wa using the mounting jig 46, is performed after the valve closing step in the branch pipe formation method described above and after the drilling machine 1 has been removed. After the mounting jig 46 has been removed, the valve closing step and the lid fixing step are performed again. As shown in Figure 31, the mounting jig 46 is set up so that the corrosion protection member 93 faces the perforation opening Wa formed by the drilling step. Next, as shown in Figure 32, when the operating rod 46a is rotated, the upper movable block 46b descends and the lower movable block 46b rises, and as the diameter of the link member 46c expands, the corrosion protection member 93 moves toward the perforation opening Wa via the holding member 46d, and the pair of contact blocks 46e come into contact with the end flange 2A of the branch pipe 2. Next, with the pair of contact blocks 46e in contact with the end flange 2A of the branch pipe 2, the operating rod 46a is rotated, and as shown in Figure 33, the cylindrical portion 93Aa of the corrosion protection member 93 expands evenly along the tapered surface 93Ba1 of the expansion member 93B, the cylindrical portion 93Aa comes into contact with the annular base 93Bb of the expansion member 93B, and the contact portion 93Aa1 and the sealing portion 93Ab come into close contact with the perforation opening Wa and are fixed in place. Next, the mounting jig 46 is detached from the corrosion protection member 93, which is composed of the annular corrosion protection seal 93A and the expansion member 93B, and the mounting jig 46 is removed.

[0113] As in this embodiment, if the mounting jig 46 for attaching the corrosion-preventive member 93 to the perforation port Wa has an expandable / contractible mechanism 46A, it becomes possible to press the corrosion-preventive member 93 against the perforation port Wa from the axial direction Y of the branch pipe 2 by utilizing the connecting openings 33, 43 (end flanges 2A of the branch pipe 2) that face the perforation port Wa, thereby ensuring that the corrosion-preventive member 93 is securely attached. Furthermore, by using this expandable / contractible mechanism 46A to detach and retrieve the mounting jig 46 from the corrosion-preventive member 93, the mounting jig 46 does not obstruct the flow path of the branch pipe 2.

[0114] (13) Figures 36 to 37 show the sealing test process and valve body mounting process according to alternative embodiment 8. Figure 38 shows the end of the valve operating member VkA according to alternative embodiment 8. The branch pipe formation method in this embodiment includes the divided member arrangement process and divided member connection process described above, a sealing test process (see Figure 36) in which the lid 5 is fixed to the cylindrical portion 31 of the first divided member 3 with contact bolts T, and water (an example of a fluid) is supplied to the inside of the first divided member 3 and the second divided member 4 to perform a sealing test, a valve body mounting process (see Figure 37) in which the contact bolts T are removed after the water supplied in the sealing test process is discharged and the valve body 6A is mounted, the perforation machine mounting process and branch flow path closure process described above, and after moving the lid 5 to form the opening 31a (opening) of the cylindrical portion 31, the perforation port formation process described above is performed.

[0115] As shown in Figure 36, in the sealing test process, the end of the branch pipe 2 is plugged (not shown), water is injected and air is vented from the opening 31a, and the lid 5, which functions as a valve and a sealing lid, is fixed in advance to the cylindrical portion 31 of the first divided member 3 for sealing testing. Then, a hydraulic coupler 55a is attached to the hydraulic hose connection port 55 of the lid 5, and hydraulic pressure is applied from this hydraulic coupler 55a to check the sealing state of the first divided member 3 and the second divided member 4 and the sealing state of the lid 5. After this sealing check, the hydraulic coupler 55a is removed, and the hydraulic hose connection port 55 is closed with a submersible plug 55h. This makes it possible to perform a sealing test before attaching the drilling machine 1, etc. Alternatively, the hydraulic hose connection port 55 may be omitted, and hydraulic pressure may be applied from the connecting openings 33 and 43 via the branch pipe 2.

[0116] Next, as shown in Figure 37, the water inside the first divided member 3 and the second divided member 4 is drained from the connecting openings 33 and 43, and the contact bolts T are removed from the lid 5. Then, after performing the attachment mounting process described above, the valve body 6A is attached to the attachment 7. This makes it possible to make the lid 5 function as a valve body and a closing lid, and the drilling process, valve closing process, lid fixing process, valve body removal process, and side wall piece mounting process described above are performed. In this way, since the lid 5 is fixed to the first divided member 3 with the contact bolts T and a sealing test is performed, and then the contact bolts T are removed and the valve body 6A is attached, the lid 5 can also be used for sealing tests. Furthermore, since the hole saw 11 of the drilling machine 1 is moved through the opening formed by moving the lid 5 to form the drilled hole Wa, the work efficiency is high. In addition, there is no risk of forgetting to set the lid 5 inside the valve body 6A.

[0117] In this embodiment, the valve body 6A includes a valve body 61 that houses the cover 5, a valve operating member VkA detachably connected to the valve body 61, and a closing plate 66 detachably connected to the valve body 61 outside the valve operating member VkA. As shown in Figures 37 to 38, the valve operating member VkA includes a plate member 67a fixed to the valve body 61 with bolts, an operating tool attachment / detachment hole portion 67b including a through hole formed in the plate member 67a, a rotating member 67c whose end rotates from one end to the other of the long groove 51a, and an operating portion 67d for engaging with the rotating member 67c and performing rotational operation. In this embodiment, the end of the rotating member 67c is fitted with a rotating member 67c1 that is rotatable with respect to the shaft 67c2. This rotating member 67c1 has a cylindrical base and a tapered frustoconical tip. This frustoconical shape allows the rotating member 67c to move the lid 5 while the rotating member 67c1 rotates smoothly against the long groove 51a, thereby reducing sliding resistance.

[0118] In this embodiment, the valve body 6A has a separate structure comprising the valve body 61, the valve operating member VkA, and the closing plate 66. Therefore, after performing a sealing test using the cover 5, which functions as the valve body and closing cover, it is easy to engage the valve operating member VkA with the cover 5.

[0119] (14) Figure 39 shows the lid replacement process according to another embodiment 9. After the drilling process is completed, if the water-sealing performance of the lid 5 is poor due to the valve closing process and lid fixing process, the lid 5 needs to be replaced. Therefore, the branch pipe formation method in this embodiment further includes a lid replacement process using a flow path blocking jig 75. In this lid replacement process, the lid 5 is opened and the water-sealing seal 75a of the flow path blocking jig 75 is expanded by compression deformation or fluid pressure, etc., to make it tightly adhere to the inner circumferential surface of the cylindrical portion 31 of the first divided member 3. Next, the closing plate 66 of the valve body 6A, the valve operating member VkA, and the lid 5 are removed in that order. Then, a new lid 5 is prepared, and the lid 5, valve operating member VkA, and closing plate 66 are installed in that order, and after the water-sealing seal 75a of the flow path blocking jig 75 is reduced and raised, the water-sealing performance of the new lid 5 is confirmed by the valve closing process and lid fixing process. In this embodiment, the closure plate 66 is detachably connected to the valve body 61, so that if there is a problem with the cover 5, it can be quickly replaced.

[0120] (15) The configurations disclosed in the embodiments described above can be combined in part or in whole.

[0121] When a lid is attached to close the connection case using a lid insertion device, as in the branch pipe forming apparatus described in Patent Document 1 disclosed in the prior art documents, work efficiency is reduced. On the other hand, although the valve device described in Patent Document 2 disclosed in the prior art documents does not require the lid insertion device, it is necessary to insert a nut from above into the insertion hole in the top plate of the housing body while the bolt is inserted into the through hole of the flange of the branch pipe section and then screw it in, which requires time and effort for the screwing operation, and there was room for improvement in terms of work efficiency.Therefore, from the above embodiment, a valve body / lid with high work efficiency having the following configuration, a branch pipe forming apparatus equipped with this valve body / lid, and a branch pipe forming method using this branch pipe forming apparatus are conceived.

[0122] (Additional notes) The characteristic configuration of the valve-body / lid according to the present invention is a valve-body / lid that functions as a valve body to block the flow path of a pipeline and also functions as a closing lid to close the pipeline, comprising a bottom wall and a side wall erected from the outer edge of the bottom wall, wherein at least one of the bottom wall and the side wall has an engagement portion that can engage with a valve operating member, and the side wall has a screw hole into which a contact bolt that abuts the outer circumferential surface of the end of the pipeline is screwed.

[0123] In this configuration, an engaging portion is formed on at least one of the bottom wall and the side wall, which can engage with a valve operating member. Therefore, the valve body, which also serves as a lid, can be moved from the outside using a moving operating member to block the flow path of the pipeline, resulting in high work efficiency.

[0124] Furthermore, the side walls of this configuration have screw holes into which contact bolts that abut the outer surface of the end of the pipeline are screwed. Therefore, when fixing the valve-integrated cover, which also serves as a sealing cover, to the pipeline, it is only necessary to operate the contact bolts from the outside and screw them into the screw holes, resulting in extremely high work efficiency. In this way, we have been able to provide a valve-integrated cover with high work efficiency.

[0125] Another characteristic feature is that the side wall is provided on a part of the outer edge of the bottom wall, and the device further includes a side wall piece that is attached to the outer edge of the bottom wall where the side wall is not present.

[0126] As in this configuration, by providing a section without a side wall, it becomes possible to pass the section without a side wall to the end of the pipeline, allowing the valve body / lid, which also functions as a valve, to slide using the moving mechanism. On the other hand, by providing a side wall piece attached to the outer edge of the bottom wall where there is no side wall, the fixed position of the valve body / lid, which also functions as a sealing lid, becomes more stable.

[0127] Another notable feature is that the bottom wall has through holes into which fixing bolts for securing the side wall pieces are inserted.

[0128] As shown in this configuration, by inserting fixing bolts into the through-holes in the bottom wall and securing the side wall pieces, the valve body / lid, which also serves as a sealing lid, can be firmly fixed to the pipeline. Moreover, by providing through-holes in the bottom wall, it becomes possible to operate the fixing bolts from above, thereby improving work efficiency.

[0129] The characteristic configuration of the branch pipe forming device according to the present invention is a branch pipe forming device that is attached to an existing pipe to form a branch pipe that communicates with a perforation opening formed by perforating a part of the outer surface of the existing pipe with a perforating machine in a non-stop flow state, and is equipped with a valve body and cover as described above, comprising a first divided member connected to each other in a sealed state by a fastening member and a second divided member located vertically below the first divided member, wherein the first divided member has a cylindrical portion having an opening through which the cutter of the perforating machine can pass, and an annular recess is formed on the outer surface of the cylindrical portion to which the tip of the contact bolt abuts.

[0130] In this configuration, the first divided member can be mounted on top of the second divided member with the second divided member positioned vertically downwards, and the first divided member can be connected to the second divided member by operating the fastening member from above. As a result, it is possible to improve work efficiency when replacing existing pipes. Moreover, if an annular recess is formed in the cylindrical part of the first divided member, the tip of the contact bolt will contact the annular recess firmly, stabilizing the fixed position of the valve body / lid that also serves as a sealing lid.

[0131] Other notable features include the fact that a valve body housing the valve body / lid is attached, and an attachment surrounds the outer surface of the cylindrical portion, the first divided member having a columnar portion with a seating surface on which the attachment is placed, and the attachment is fixed to the first divided member by bolts screwed into the columnar portion.

[0132] By providing an attachment like the one described, the position of the valve body can be stabilized, allowing the valve body / lid, which also functions as the valve element, to move smoothly. Moreover, this attachment is fixed simply by screwing a bolt into the columnar part provided on the first segmented member, resulting in extremely high work efficiency.

[0133] Another characteristic feature of the valve body is that it comprises a valve body main body, a valve operating member connected to the valve body main body, and a closing plate detachably connected to the valve body main body outside the valve operating member.

[0134] As in this configuration, by connecting the closure plate to the valve body in a detachable manner, the valve body / lid can be quickly replaced if there is a problem.

[0135] The branch pipe forming method using the branch pipe forming apparatus described above is characterized by: a branch member placement step in which the first branch member and the second branch member are placed on the existing pipe such that the cut surface of the first branch member and the cut surface of the second branch member are aligned with a plane that includes the axis of the existing pipe and the axis of the branch pipe; a branch member connecting step in which the end of the branch pipe is clamped in the connecting opening between the first branch member and the second branch member and the first branch member is connected in a sealed state by fastening members; and fixing the valve body / lid to the first branch member with the contact bolt, and the first branch member and the second branch member The present invention includes a sealing test step of supplying fluid into the interior and performing a sealing test; a valve body mounting step of removing the contact bolt and mounting the valve body after discharging the fluid from the sealing test step; a drilling machine mounting step of mounting the drilling machine to the first divided member; a branch passage closure step of closing the gate valve provided in the branch pipe; and a drilling port forming step of moving the valve body / lid to form the opening, and then moving the cutter of the drilling machine into the cutter housing space formed between the first divided member and the second divided member to form the drilling port at a position adjacent to the cutter housing space.

[0136] In this method, the first and second dividing members constituting the branch pipe forming device are sealed and connected by a cut surface that aligns with the plane containing the axis of the existing pipe and the axis of the branch pipe. Therefore, for example, it is possible to mount the first dividing member on top of the second dividing member with the second dividing member positioned vertically downwards, allowing the cutter housing space inside the second dividing member to be visible and enabling the first dividing member to be connected to the second dividing member by operating the fastening member from above. As a result, it is possible to improve work efficiency when replacing existing pipes.

[0137] Furthermore, since the valve body / lid is fixed to the first segmented member with contact bolts for a sealing test, and then the contact bolts are removed and the valve body is attached, the valve body / lid can also be used for sealing tests. Moreover, since the perforation port is formed by moving the cutter of the drilling machine through the opening created by moving this valve body / lid, the work efficiency is high. Thus, a highly efficient method for forming branch pipes has been provided. [Industrial applicability]

[0138] The present invention can be used in a branch pipe forming device and branch pipe forming method that are attached to an existing pipe in order to form a branch pipe that communicates with a perforation opening formed by perforating a part of the outer surface of the existing pipe with a perforating machine in a non-stop flow state. [Explanation of symbols]

[0139] 1:Drilling machine 2: Branch pipe 2A: End flange (end) 3: First divided member 3a: First cutting surface (cutting surface) 4: Second divided member 4a:Second cutting surface (cutting surface) 5: Cover (cover also serves as valve body) 6: Valve box 7: Attachments 8: Guide tube 9: Flat plate member 11: Hole saw (cutter) 11a: Cutting insert 12: Center Drill 12a1: Annular recess 15: Vibration damping material 15a: Elastic member 31: Cylindrical part (pipe line) 31a: Opening 31a1: Annular recess (outer surface of the end) 31c: Columnar part 31c2: Seat 33:First connection opening (connection opening) 41: Bottom 41a: Recessed part 41b: Engaging recess 43:Second connection opening (connection opening) 46: Mounting jig 46A: Telescopic mechanism 51: Bottom wall 51a: Long groove (engaging part) 51b: Through hole 52: Side wall 52a: Screw hole 53: Side wall piece 82: Protrusion 84a: Engaging member 84a1: Tapered surface 84b: Compression coil spring (biasing member) 92: Ring-shaped protrusion 93: Corrosion-resistant material 93A: Ring-shaped corrosion protection seal 93B: Expansion member 93Ba1: Tapered surface 100: Branch pipe forming apparatus B: Fastening member J: Axle-holding bolt (bolt) K: Fixing bolt Sp: Cutter storage space T: Contact bolt V: Gate valve Vk: Valve operating member W: Water pipe (existing pipe) Wa: Perforation port X: Axial center Y: Axial center Z: Axial center

Claims

1. A branch pipe forming device attached to an existing pipe in order to form a branch pipe that communicates with a perforation opening formed by perforating a part of the outer surface of the existing pipe with a perforating machine in a state of continuous flow, The device comprises a first split member having a split surface along a plane including the axis of the existing pipe and the axis of the branch pipe, and connected to each other by a fastening member in a sealed state; a second split member; a cylindrical guide tube for inserting and guiding the center drill of the drilling machine; and a flat plate member placed on the bottom of the second split member and connected to the guide tube. The first divided member has a cylindrical portion having an opening through which the cutter of the drilling machine can pass, Between the first dividing member and the second dividing member, a cutter housing space is formed at a position adjacent to the perforation opening formed in a direction perpendicular to the plane, in which the cutter can be housed. The axis of the cylindrical portion is located on the side of the branch pipe rather than the outer surface of the existing pipe in the cutter housing space. A connecting opening is formed at the connection point between the first divided member and the second divided member, facing each other via the perforation opening and the cutter housing space, and this connecting opening clamps the end of the branch pipe in a sealed state. A branch pipe forming device having a receiving recess for accommodating the flat plate member and an engaging recess or engaging projection in the center of the receiving recess into which the end of the guide tube engages.

2. The branch pipe forming apparatus according to claim 1, wherein the flat plate member is composed of a plurality of divided plates.

3. The branch pipe forming apparatus according to claim 1 or 2, wherein an annular projection is formed on the outer edge of the flat plate member, projecting toward the side of the perforation opening.

4. The end of the guide tube has a projection that extends radially outward and is connected to the flat plate member. The branch pipe forming apparatus according to any one of claims 1 to 3, wherein the inside of the protrusion houses an engaging member that can engage with an annular recess formed on the outer circumferential surface of the center drill, and a biasing member that biases the engaging member radially inward toward the annular recess.

5. The engaging member has a tapered surface that can contact the tip of the center drill. The branch pipe forming apparatus according to claim 4, wherein the tip of the center drill contacts the tapered surface, causing the engaging member to move radially outward against the biasing force of the biasing member.

6. A branch pipe forming device attached to an existing pipe in order to form a branch pipe that communicates with a perforation opening formed by perforating a part of the outer surface of the existing pipe with a perforating machine in a state of continuous flow, The device comprises a first split member having a split surface along a plane including the axis of the existing pipe and the axis of the branch pipe, and connected to each other by a fastening member in a sealed state, a second split member, and a cylindrical guide tube into which the center drill of the drilling machine is inserted and guided, The first divided member has a cylindrical portion having an opening through which the cutter of the drilling machine can pass, Between the first dividing member and the second dividing member, a cutter housing space is formed at a position adjacent to the perforation opening formed in a direction perpendicular to the plane, in which the cutter can be housed. The axis of the cylindrical portion is located on the side of the branch pipe rather than the outer surface of the existing pipe in the cutter housing space. A connecting opening is formed at the connection point between the first divided member and the second divided member, facing each other via the perforation opening and the cutter housing space, and this connecting opening clamps the end of the branch pipe in a sealed state. The guide tube extends from the second divided member toward the opening side beyond the cut surface, A branch pipe forming device in which a bolt is screwed into the guide tube, which contacts the lower vertical side of the outer surface of the existing pipe.

7. The branch pipe forming apparatus according to any one of claims 1 to 6, wherein the cutter housing space houses the cutter having a smaller diameter than the outer diameter of the existing pipe.

8. The branch pipe forming apparatus according to any one of claims 1 to 7, wherein the axis of the guide cylinder is perpendicular to the cut surface.

9. A branch pipe forming device attached to an existing pipe in order to form a branch pipe that communicates with a perforation opening formed by perforating a part of the outer surface of the existing pipe with a perforating machine in a state of continuous flow, It comprises a first divided member and a second divided member that are connected to each other by fastening members in a sealed state, Between the first divided member and the second divided member, a cutter housing space is formed at a position adjacent to the perforation opening, in which the cutter of the perforation machine can be housed. The cutter has a cylindrical hole saw with a cutting tip at its tip, The aforementioned hole saw has a disc-shaped vibration damping member inserted inside to absorb vibrations. A branch pipe forming apparatus is provided in which an elastic member that contacts the inner surface of the hole saw is fixed to the outer peripheral end surface of the vibration damping member.

10. The branch pipe forming apparatus according to claim 9, wherein the elastic member is divided into multiple parts so as not to overlap with the cutting tip when viewed in the direction of the rotation axis of the hole saw.

11. The mounting jig for attaching a corrosion-preventive member to the aforementioned perforation opening is further provided. The branch pipe forming apparatus according to any one of claims 1 to 10, wherein the mounting jig has an expandable and contractible mechanism that allows the corrosion-preventive member to be pressed against the perforation opening from the axial direction of the branch pipe and to be detached from the corrosion-preventive member.

12. The branch pipe forming apparatus according to claim 11, wherein the corrosion protection member includes an annular corrosion protection seal conforming to the shape of the perforation opening and an expanding member that expands the diameter of the annular corrosion protection seal by a tapered surface that abuts against the inner circumferential surface of the annular corrosion protection seal.

13. A method for forming a branch pipe using a branch pipe forming apparatus according to any one of claims 1 to 12, A division member placement step in which the first division member and the second division member are placed in the existing pipe, A division member connecting step involves sandwiching the end of the branch pipe between the first division member and the second division member, and connecting the first division member and the second division member in a sealed state with a fastening member, A drilling machine mounting step involves attaching the drilling machine to the first divided member, A branch channel closure step is performed by closing a gate valve provided in the branch pipe, A method for forming a branch pipe, comprising a step of forming a perforation port by moving the cutter into the cutter housing space and forming the perforation port at a position adjacent to the cutter housing space.

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