JPH0558264U - Bead generation prevention device and butt welding device using the same - Google Patents

Abstract

(57) [Summary] [Object] To provide a bead generation preventing device capable of preventing the generation of a beat and a butt welding device of a synthetic resin pipe using this device. [Structure] The bead generation preventing device 300 includes a flexible tubular body 301 and both ends 3 of the tubular body 301 which are expandable and contractible.
A pair of lids 304 fixedly attached to 02 and 303
And 305, and a pair of lids 304 and 305 are bridged to be arranged in an inside 306 of the tubular body 301, and a rigid bridging member 308 having a plurality of holes 307 formed therein, and an inside of the bridging member 308. One end 310 is opened at 309, and a long air supply / exhaust pipe 311 is provided so as to penetrate one lid portion 305.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention is a bead generation preventing device and a synthetic resin including the bead generation preventing device for preventing the generation of beads on the inner surface of a pipe by butt welding to a pipe made of a heat-melting synthetic resin such as polyarylene sulfide containing a polyphenylene sulfide resin (hereinafter referred to as PPS). The present invention relates to a butt welding device for pipe manufacturing.

[0002]

[Prior Art]

 A synthetic resin pipe made of PPS or the like has a very small amount of water-soluble components, and therefore is suitable for use as a pipe for ultrapure water for cleaning in the production of electronic devices such as ultra-LSI. When connecting pipes made of PPS resin or the like, it is difficult to join them with an adhesive, or because elution from the adhesive becomes a problem, the ends of the pipes are melted and joined by heat. Butt welding is widely used. In such butt welding, there may be a case where protrusions (also called burrs) called beads are formed on the inner and outer surfaces of the pipe when the pipe end surfaces are pressed and welded after being heated and melted. If such a bead is present especially on the inner surface of the joint, the flow of the fluid in the pipe will be disturbed there, causing the accumulation of fine particles and the generation of bacteria and algae, making it unsuitable as a pipe for ultrapure water. .. Therefore, in order to prevent the occurrence of this bead, for example, an internal bead generation preventing device for a butt-welded pipe disclosed in Japanese Patent Publication No. 50-9017 or a welding method for welding a plastic tubular body disclosed in Japanese Utility Model Publication No. 61-138530. A tool is disclosed.

[0003]

[Problems to be solved by the device]

 The device for preventing inner bead generation of a butt-welded pipe disclosed in Japanese Patent Publication No. 509017 discloses a support pole fixed to a back ring, which is elastically linked by a turnbuckle to release the tension from the support pole. However, with this device, mounting on the pipe to be butt-welded is extremely troublesome, and it is necessary to mount it inside the pipe before heating and contact the buckling with the inner surface of the pipe. It is difficult for the heat to escape via the back ring to uniformly heat and melt the end surface of the pipe, and there is a possibility that an unbonded portion consisting of a minute gap will be formed on the inner surface of the pipe after bonding. Such unbonded parts may cause breakage accidents, cause bacteria and algae, and accumulate fine particles as well as beads.

A welding tool for welding plastic tubular bodies disclosed in Japanese Utility Model Laid-Open No. 61-138530 is composed of a plurality of pressing ring pieces having an arcuate portion on the outside, and the pressing ring pieces are moved in the radial direction. It is equipped with a pressure ring that can be expanded and reduced in diameter by this, but according to this, the outer surface of the pressure ring becomes a perfect circle only after the diameter is expanded, so that it matches the diameter of that perfect circle. It can only be used for butt welding of pipes with an inner diameter, and it is difficult to press the outer surface of the press ring exactly against the inner surface of the pipe in response to minute undulations on the inner surface of the pipe. Since the moving position of the other pressing ring piece is determined by the moving position in the radial direction of, it is actually difficult to make the outer surface of the pressing ring into a perfect circle, and bead generation is prevented to such a good degree. Can Not a thing.

Further, the above-described conventional bead generation preventing device has a problem that the inner surface of the pipe is damaged when the device is inserted and removed through the welded pipe because it is mainly formed of a metal member. And this tendency is especially remarkable in a long and soft welded pipe. As with beads, the damage in the tube causes the generation of bacteria and algae, and the accumulation of fine particles, which is not preferable.

The present invention has been made in view of the above points, and an object of the present invention is to use a bead generation preventing device and a device which can prevent the occurrence of beats by solving the above problems. An object of the present invention is to provide a butt welding device for synthetic resin pipes.

[0007]

[Means for Solving the Problems]

 According to the present invention, the above-described object is a bead generation preventing device used in a butt welding device for synthetic resin pipes, which includes a long air supply / discharge pipe and a flexible tube arranged at one end thereof. A tubular body and an air source connected to the other end, the air supply / exhaust pipe is open inside the tubular body at the one end, and the tubular body is the air supplied / exhausted from the air source. This is achieved by a bead generation preventing device that is expanded or contracted by

Further, according to the present invention, the above-mentioned object is used by arranging a pair of chucks for sandwiching respective ends of a pair of synthetic resin tubes to be welded, and between the chucks. A movable spacer that sets the end face distance, a movable heating plate that is placed with a gap between the end faces of the pipe whose end face distance is set to a predetermined value, and heats both end faces in a non-contact state. A heating plate moving device that moves between the surfaces and the outside thereof, and a chuck moving device that moves at least one of the pair of chucks and presses the end faces melted and heated by the heating plate with a predetermined pressure. A butt welding device for synthetic resin pipes, comprising a bead generation preventing device for preventing the generation of beads on the inner surfaces of the pair of pipes in this pressure welding, the bead generation preventing device being inserted into the inside of the pair of pipes. It is removable And an elongated air supply / exhaust pipe, a flexible tubular body disposed at one end thereof, and an air source connected to the other end thereof. One end of the tubular body is opened to the inside of the tubular body, and the tubular body is achieved by a butt welding device of a synthetic resin pipe that is expanded or contracted by the air supplied and exhausted from the air source.

In the present invention, it is preferable to use a heat-resistant rubber which has flexibility in addition to flexibility as the cylindrical body, but it is more preferably formed from silicone rubber or fluororubber. As the fluororubber, Viton (trade name) manufactured by VALQUA CO., LTD. Or perfluororubber (trade name) manufactured by Daikin Co., Ltd. can be used as an example. The air supply / exhaust pipe may be rigid, but it is flexible, that is, bendable so that it can be applied to butt welding of curved pipes such as elbows and does not damage the inner surface of the welded pipe during insertion / removal. I hope you are doing it.

Further preferably in the present invention, the butt welding device is a chuck drive device for switching a chuck between a pair of pipes between a clamped state and a clamped state, and a spacer between a pair of chucks and the outside thereof. And a spacer moving device for moving the heating plate, and the heating plate is rotatably provided. The heating plate moving device rotates the heating plate so that it is opposed to the pair of tubes. It is equipped with a rotary actuator that moves between the end faces and outwards.

In the present invention, the pair of chucks may be provided with a sealing device that seals around the end faces of the pair of tubes heated by the heating plates.

[0012]

[Action]

 In the bead generation preventing device of the present invention, the flexible tubular body is inserted into one of the pipes to be butt-welded from one end thereof. The flexible tubular body inserted in this tube is placed in the heated and melted joint. When pressurized air was sent into the inside of the tubular body through the air supply / exhaust pipe together with the pressure bonding of this joint, the tubular body was radially expanded like a balloon and its outer surface was heated and melted. It is pressed against the inner surface of the pipe including the joint portion, which prevents the melted portion from rising inside when the joint portion is pressure-bonded. After cooling the joint, the introduced pressurized air is discharged through the air supply / exhaust pipe, and as a result, the tubular body is contracted to its original shape and drawn out of the pipe.

The present invention will now be described in more detail based on the preferred embodiments shown in the drawings. The present invention is not limited to these specific examples.

[0014]

【Concrete example】

 In FIG. 1, a bead generation preventing apparatus 300 of this example includes an expandable and flexible cylindrical body 301 and a pair of lids 304 fixed to both ends 302 and 303 of the cylindrical body 301. , 305, and a rigid bridging member 308, which is arranged in the inside 306 of the tubular body 301 by bridging the pair of lids 304 and 305, and has a plurality of holes 307, and the inside 306, the present example. Then, one end 310 is opened in the inside 309 of the bridging member 308, and a long air supply / exhaust pipe 311 is arranged so as to penetrate the one lid portion 305. Here, the inside 306 is a closed space surrounded by the tubular body 301 and the lids 304 and 305, and is kept airtight except that it communicates with the other end (not shown) of the air supply / exhaust pipe 311. There is. In addition, the bridging member 308 does not necessarily have to be provided, and for example, one end 310 of the air supply / exhaust pipe 311 is fixed to the lid 304, and a plurality of side members of the air supply / exhaust pipe 311 are provided in the internal space 306. The communication hole may be provided. That is, the air supply / exhaust pipe 311 itself can be a member bridging the lid portions 304 and 305.

In this example, as the tubular body 301, a stretchable silicone rubber having a thickness of about 1 mm is used. If the tubular body 301 is flexible and expandable / contractible, it does not need to be expandable / contractible but may be small in elasticity. In the case of the tubular body 301 having a small stretchability, the tubular body having the shape indicated by the alternate long and short dash line in FIG. 1 in advance, that is, the outer diameter which is substantially the same as the inner diameter of the tube which comes into contact with the inner surface of the tube by slightly pressing the inner space 306. A tubular body 301 having a is preferably used. In this case, it is preferable that the bead generation preventing device 300 be inserted into and removed from the welded pipe in a state where the inner space 306 is slightly decompressed and the tubular body 301 is folded. The thickness of the tubular body 301 is not limited to the thickness of about 1 mm as in this example, but generally, the thinner the shape, the better the shape of the inner surfaces of the pipes 2 and 3 to be welded. However, it is preferable from the viewpoint of bringing the tubular body 301 into contact with the inner surface of the tube. However, in this case, since high-pressure pressurized air is introduced into the inside 306 of the cylindrical body 301 in order to reliably prevent the generation of beads, the pressure must be high enough to prevent the high-pressure pressurized air from bursting. is necessary. Further, in order to effectively prevent the formation of beads, the tubular body 301 is required to have appropriate rigidity.

In this example, each of the lids 304 and 305 is formed of a rigid member that is a separate member from the tubular body 301, but instead of this, it is integrally formed of the same material as the tubular body 301. The tubular body 301 may be formed in a balloon shape. In this case, the lid portions 304 and 305 may be formed with a large thickness so as not to be deformed or expanded by compressed air, but the invention is not limited thereto.

In the embodiment shown in FIG. 1, the tubular body 301 is arranged at one end of the air supply / exhaust pipe 311 and is fixed and supported at one point 322 thereof via the lid 305. Further, in the above-described modification in which the air supply / exhaust pipe 311 also serves as the bridging member 308, the tubular body 301 is fixed at the two ends of the one end of the air supply / exhaust pipe 311 via the lids 304 and 305. And is supported. In the case of the tubular body 301 in which the tubular body 301 and the lids 304 and 305 described above are integrally formed of the same material to have a balloon shape, the balloon is the air supply / exhaust pipe 311 as in the modified example. Preferably, it is fixed and supported at two points at one end. This is because in the two-point support, when the internal space 306 is pressurized to inflate the balloon, the inflation in the length direction is suppressed. At this time, a plug for sealing is provided at one end 310 of the air supply / exhaust pipe 311 if necessary.

The air supply / exhaust pipe 311 is long enough to be inserted into the joint portion of the pipes, and is formed in this example with flexibility. The other end of the air supply / exhaust pipe 311 opposite to the one end 310 is connected to an air source (not shown) such as a compression pump.

In the bead generation preventing apparatus 300 formed as described above, for example, in the case of butt welding of the end faces 9 and 10 of the tubes 2 and 3 sandwiched by the chucks 6 and 7, respectively, the tubular body 301 Is inserted into the tube 3 from one end of one tube 3 to be butt-welded, and its central portion is arranged at the end faces 9 and 10. The end faces 9 and 10 of the pipes 2 and 3 to be butt-welded are heated by a heating plate or the like to be melted, and then the chuck 7 is brought close to the chuck 6 and the end faces 9 and 10 are pressed against each other. When pressurized air is sent into the inside 306 of the tubular body 301 via the air supply / exhaust pipe 311 together with this pressure contact, the tubular body 301 is expanded in the radial direction like a balloon as shown by the one-dot chain line in FIG. Its outer surface 315 is pressed against the inner surface 316 of the tubes 2 and 3 including the heated and melted end surfaces 9 and 10 and, as a result, of the melted portion produced during the compression between the heated and melted end surfaces 9 and 10. It prevents swelling of the meat on the inner surface 316 side, that is, generation of beads. After cooling the joint, the introduced pressurized air is discharged through the air supply / discharge pipe 311 and the tubular body 301 is contracted to its original shape and drawn out of the pipes 2 and 3.

By the way, since the bead generation preventing apparatus 300 is provided with the flexible tubular body 301, it is extremely easy to mount it in the pipes 2 and 3 to be butt-welded, and before the heating, It is not necessary to contact the inner surfaces 316 of 2 and 3 and the cylindrical body 301 may be expanded after heating and melting, and the end surfaces 9 and 10 of the tubes 2 and 3 can be uniformly heated and melted. It is also possible to eliminate the possibility that an unbonded portion composed of a minute gap is formed on the inner surface. Further, by making the tubular body 301 which expands and contracts independently to contact with the inner surface 316 of the pipes 2 and 3 and press it, it can be used for butt welding of various pipes having different diameters. Even if there is a slight undulation on the inner surface 316 of the tubes 2 and 3, the outer surface 315 of the tubular body 301 can be pressed correspondingly to the inner surface 316 of the tube 2 and 3, and as a result, the bead can be pressed. Can be more preferably prevented. Further, in the bead generation preventing device 300, since the flexible tubular body 301 is inflated by the pressurized air, the tubular body 301 can be extremely easily arranged along the inner surfaces 316 of the tubes 2 and 3. ..

When the bead generation preventing device 300 is used, if the grooves 320 and 321 are formed in advance on the end faces 9 and 10 of the pipes 2 and 3, respectively, as shown in FIG. It is possible to preferably prevent the generation of beads by accumulating the molten protrusion portion in the annular groove between the formed grooves 320 and 321.

Next, an example of a butt welding device 1 for a synthetic resin pipe using the above bead generation preventing device 300 will be described with reference to FIGS. 2 to 6.

As shown in FIG. 2 to FIG. 6, the butt welding apparatus 1 for a synthetic resin pipe of this example includes a pair of pipes 2 and 3 made of a synthetic resin to be butt welded, and in this example, made of PPS. A pair of chucks 6 and 7 for holding the end portions 4 and 5, and a chuck driving device 8 for holding the chucks 6 and 7 against the tubes 2 and 3 and releasing the holding state (the chuck 7 side is not shown). And a movable spacer 11 arranged between the chucks 6 and 7 for setting the surface distance D1 of the end faces 9 and 10 of the tubes 2 and 3 to a predetermined value, and the spacer 11 between the chucks 6 and 7 and outside thereof. A spacer moving device 12 for moving the pipes 2 and 3 and pipe end faces 9 and 10 whose distance D1 is set to a predetermined value by the spacer 11 with gaps D2 and D3 between the pipes 2 and 3 facing each other. 10 that heats 10 in a non-contact state The heating plate 13, a heating plate moving device 14 for moving the heating plate 13 to and from the opposite end surfaces 9 and 10 of the tubes 2 and 3, and at least one of the chucks 6 and 7, and in this example, the chuck 7 Is moved to bring the end faces 9 and 10 of the tubes 2 and 3 heated and melted by the heating plate 13 into pressure contact with each other with a predetermined pressure, the bead generation preventing device 300 described above, and the chuck driving device 8 The spacer moving device 12, the heating plate moving device 14, the chuck moving device 15, and the control device 16 for controlling the operation of the bead generation preventing device 300.

The chuck 6 is composed of two lower chuck plates 21 and 22 fixed to the frame 20 of the apparatus and two upper chuck plates rotatably attached to the frame 20 in the A direction by shafts 23 and 24. The ends 4 of the tube 2 are received substantially in the center of the upper surfaces 28 and 29 of the lower chuck plates 21 and 22 which are provided in parallel with each other and are bridged by the rear plate 27. The semicircular recesses 30 and 31 are formed, and the semicircular recesses 30 and 31 are formed substantially at the centers of the lower surfaces 33 and 34 of the upper chuck plates 25 and 26 which are bridged by the rear plate 32 and arranged in parallel with each other. Corresponding to 3 and 31, semi-circular recesses 35 and 36 for receiving the end 4 of the tube 2 are formed. Positioning pins 37 and 38 are further planted on the lower surfaces 33 and 34, and holes 39 and 40 are formed on the upper surfaces 28 and 29 of the lower chuck plates 21 and 22 so that the pins 37 and 38 are fitted therein. It is set up. On the other hand, the chuck 7 is formed in substantially the same manner as the chuck 6 except that the chuck 7 is provided on the moving base 45 of the chuck moving device 15. That is, the two lower chuck plates 46 and 47 fixed to the movable table 45 and the rear plate 48 which holds the lower chuck plates 46 and 47 in parallel with each other and bridges them in the A direction via the shafts 49 and 50. It is provided with two upper chuck plates 51 and 52 rotatably attached, and the end 5 of the tube 3 is received in the substantially center of the upper surfaces 53 and 54 of the lower chuck plates 46 and 47. Semi-circular recesses 55 and 56 are formed, and the semi-circular recess 55 is formed substantially at the center of the lower surfaces 58 and 59 of the upper chuck plates 51 and 52 which are bridged by the rear plate 57 and arranged parallel to each other. And 56 corresponding to the semi-circular recesses 60 and 61 for receiving the end 5 of the tube 3. Positioning pins 62 and 63 are further implanted in the lower surfaces 58 and 59, and holes 64 and 65 are formed in the upper surfaces 53 and 54 of the lower chuck plates 46 and 47 so that the pins 62 and 63 are fitted therein. It is set up.

The chuck driving device 8 includes an air cylinder 70, one end 71 of the air cylinder 70 is rotatably connected to a bracket 73 via a shaft 72, and the bracket 73 is bolted to the frame 20. It is fixed by etc. A piston rod 74 of the air cylinder 70 is rotatably connected to a bracket 76 via a shaft 75, and the bracket 76 is fixed to the rear plate 32 of the chuck 6 by bolts or the like. When the piston rod 74 is expanded and contracted in the B direction by the operation of the air cylinder 70, the upper chuck plates 25 and 26 of the chuck 6 are rotated in the A direction around the shafts 23 and 24 via the bracket 76 and the rear plate 32. Thus, the chuck 6 is clamped and released from the tube 2 in this manner.

The chuck driving device on the chuck 7 side (not shown) also includes an air cylinder, and the chuck driving device on the chuck 7 side has one end of the air cylinder rotatably connected to the moving table 45. Except for the above, the structure is the same as that of the chuck driving device 8. Therefore, when the air cylinder of the chuck driving device on the chuck 7 side is operated, the upper chuck plates 51 and 52 of the chuck 7 center around the shafts 49 and 50. The chuck 7 is rotated in the A direction, and the chuck 7 is clamped with respect to the tube 3 in synchronism with the chuck 6 to be in a clamped / unclamped state. Since the chuck driving device on the chuck 7 side operates in the same manner as the chuck driving device 8 in this manner, the description thereof will be omitted below. It is preferable to construct the air cylinder as the power source for the chucks 6 and 7 in this way, because the pipes 2 and 3 can be aeroelastically sandwiched, but the present invention is not limited to this, and for example, a hydraulic cylinder or a pneumatic cylinder can be used. Alternatively, a hydraulic rotary actuator or an electric motor may be used.

The chuck driving device of the present invention does not necessarily have to be used, and the fasteners of the chucks 6 and 7 may be manually locked and unlocked. As a fastening tool in this case, for example, a push screw rotatably supported is arranged on the side surface of the lower chuck plate 21 opposite to the shaft 23 in FIG. An example is one in which a screw insertion groove is formed on the side surface corresponding to the opposite set screw. However, it is more preferable that the chucks 6 and 7 are clamped automatically by a chuck driving device. This is because, when the chuck driving device is used, when the end faces 9 and 10 of the pipes are opposed to each other and abutted against the spacer 11 by holding each of the pipes to be brought into contact with each other, the left and right pipes are evenly distributed, as will be described later. It can be pressed into contact and when the heating plate 13 is brought into the heating position, the gaps D2, D3 between the heating plate 13 and the end faces 9 and 10 of the tube can be exactly equal. On the other hand, in the case of manual operation, the chucks 6 or 7 are clamped separately, which not only lowers the productivity but also makes it difficult to contact them by a uniform pressure, so that the pipe may be clamped obliquely. , The gaps D2 and D3 may be sandwiched slightly differently.

In this example, the spacer 11 is made of a square rod-shaped member having a thickness D1 = 40 mm, but it is needless to say that the spacer 11 may be a plate-shaped member like the heating plate 13 and the thickness D1 is also the same. It is needless to say that it is not limited to the above, but is determined from the thickness of the heating plate 13 and the set values of the gaps D2 and D3. The spacer moving device 12 is composed of a pneumatic rotary actuator 82 mounted in a recess 81 of the frame 20, one end of the spacer 11 is fixed to an output rotary shaft 83 of the actuator 82, and the actuator 82 is operated. Then, the spacer 11 is rotated in the C direction, and is moved between the chucks 6 and 7 and outside thereof. Instead of the rotary actuator 82, for example, a hydraulic rotary actuator or an electric motor, or a direct-acting actuator may be used.

It should be noted that the spacer moving device 12 may insert and remove the spacer 11 not by rotational movement between the use position between the chucks 6 and 7 and the outside thereof but by linear movement. Further, the spacer moving device 12 of the present invention does not necessarily have to be used, and may be manually inserted and removed. In any case, it is preferable that the spacer 11 is inserted as perpendicularly as possible to the central axis of the pipes to be joined in the longitudinal direction.

In this example, the heating plate 13 is made of a porous ceramic plate containing nichrome wire, but other heating plates adapted to uniformly heat the end faces 9 and 10 of the tubes 2 and 3 are used. For example, a rod-shaped heating wire may be uniformly embedded in the entire surface of an electrically insulating member such as ceramic. The surface temperature of the heating plate 13 can be appropriately determined according to the melting temperatures of the pipes 2 and 3 to be butt-welded, the gaps D2 and D3, the heating time, etc., but in this example where D2 = D3 = 0.5 mm, 450 ° C. to 459 ° C. The range of ° C is preferably used. The heating plate driving device 14 includes a pneumatic rotary actuator 92 mounted on the frame 20 via a bracket 91, and one end 95 of an arm 94 is fixed to an output rotation shaft 93 of the actuator 92. The heating plate 13 is attached to the other end of the arm 94, and when the actuator 92 is actuated and the arm 94 is rotated in the E direction, the heating plate 13 is also rotated in the E direction and the tubes 2 and 3 is moved between the opposite end faces 9 and 10 and out of it. The rotary actuator 92 may be replaced with a hydraulic rotary actuator or an electric motor, or a direct drive actuator.

The chuck moving device 15 is arranged with the air cylinder 101 supported at one end by the support member 100, the moving table 45 fixed to the tip of the piston rod 102 of the air cylinder 101, and the piston rod 102 in between. It is equipped with two guide rods 103 and 104, and a valve circuit 106 that controls the supply and discharge of the air pressure of the compressed air source 105 to and from the air cylinder 101. The valve circuit 106 is a precision pressure reducing valve 107 and a direction switching valve. When the air cylinder 101 is actuated by the air pressure supplied from the valve circuit 106 and the piston rod 102 is expanded and contracted in the F direction, the movable table 45 is guided by the guide rods 103 and 104. Also in the F direction, so that the chuck 7 is also moved in the F direction. The chuck moving device 15 moves the chuck 7 toward the chuck 6 and, at the same time, presses the end faces 9 and 10 of the tube heated and melted by the heating plate 13 at a predetermined pressure. At this time, the pressure contact pressure transmitted to the end surfaces 9 and 10 is determined by the product of the difference in air pressure applied to both surfaces of the piston 101a that reciprocates in the cylinder 101 and the cross-sectional area of the piston 101a, as described with reference to FIG. It The pressures of the two compartments 101b and 101c in the cylinder 101 with the piston 101a interposed therebetween are switched by the solenoid valve 108 such that one is the decompression pressure of the precision decompression valve 107 and the other is the atmosphere opening pressure. .. Therefore, the pressure of the pressure contact is uniquely determined by the pressure reduction pressure of the precision pressure reducing valve 107 unless the pressure contact area of the end faces 9 and 10 is changed, and the pressure is always constant in the pressure contact process. No special detection device is required. The crimping pressure for the end faces 9 and 10 of the pipes 2 and 3 can be determined by the presence or absence of a groove on the end faces 9 and 10 of the pipes 2 and 3, the heating time, the material of the pipes 2 and 3, and the like. When the tip angle is 30 degrees, the groove length is 1 mm, the heating time is 45 seconds, and D2 = D3 = 0.5 mm, the pressure is about 3 kg per square centimeter. In this example, the air cylinder 101 is used as the power source of the chuck moving device 15 to obtain the air-elastic pressure bonding pressure, but instead of this, a hydraulic cylinder or an electric motor may be used as in the above devices. Of course it's good. The movable table 45 is provided with a recess 109. When the chuck 7 is moved toward the chuck 6, the spacer 11 is housed in the recess 109 so that the movable table 45 does not collide with the spacer 11. ..

In this example, in addition to the above-described configuration, the bead generation prevention device 300 includes a pinch roller 330 that holds the air supply / discharge pipe 31 1 and moves it, an electric motor that rotates the pinch roller 330, and an air supply / discharge device. A driving device 331 including a valve circuit for controlling the supply and discharge of the pressurized air from the air source to the pipe 311 is provided.

The control device 16 includes a control electric circuit 110, a foot switch 111 for instructing an operation start, a reset push button switch 112, a dual type timer 113 for setting a heating time and a pressing time, and a limiter. The switches 114 to 119 are provided. The electric circuit 110 performs a later-described operation based on electric signals from the switches 111, 112, 114 to 119 and the timer 113, so that the spacer driving device 12, the chuck driving device 8, the heating plate driving device 14, and the chuck are operated. Actuating signals are sent to the solenoid valves of the respective valve circuits 120, 121, 123 and 106 of the moving device 15 and the drive device 331. The electric circuit 110 including the timer 113 may be configured by a microcomputer so that the operation of the matching device 1 is performed by a program stored in advance. The switch 114 moves the clamping release position shown in FIG. 2 when the upper chuck plates 25, 26, 51 and 52 are rotated in the A direction, and the switch 115 rotates the upper chuck plates 25, 26, 51 and 52 in the A direction. 7 in operation, the switch 116 is in the upper rotation position shown in FIG. 2 when the spacer 11 is rotating in the C direction, and the switch 117 is when the spacer 11 is rotating in the C direction. 2, the switch 118 is the left rotation position shown in FIG. 2 when the heating plate 13 is rotated in the E direction, and the switch 119 is the same as the rotation position of the heating plate 13 in the E direction. In FIG. 7, the right turning positions shown by the alternate long and short dash lines in FIG. 7 are detected and their electric signals are sent to the electric circuit 110. The heating time measured by the timer 113 is 45 seconds in this example, but this time is the surface temperature of the heating plate 13, the melting temperature of the end faces 9 and 10 determined by the material of the tubes 2 and 3, the gaps D2 and D3, and It can be set appropriately depending on the presence or absence of the groove. The frame 20 and the supporting member 100 are attached to a base 131 having a roller 130, respectively.

Further, the control device 16 may be provided with a temperature indicating regulator which controls the power supply to the heating plate 13, for example, which is used in combination with a voltage regulator or a temperature sensor incorporated in the heating plate 13. good.

The butt welding apparatus 1 described above operates as follows. First, the upper chuck plates 25, 26, 51, 52, the spacer 11 and the heating plate 13 are respectively arranged at the non-sandwiched position, the upper rotation position and the left rotation position as shown in FIG. Is arranged at a position farthest from the chuck 6 as shown in FIG. In this state, the end portions 9 and 10 of the tubes 2 and 3 are manually brought into contact with the opposite side surfaces of the spacer 11, respectively, so that the end portion 4 is in the recesses 30 and 31, and the end portion 5 is in the recesses 55 and 56. Will be distributed. Further, the air supply / exhaust pipe 311 is manually fed out, the tubular body 301 is inserted into the pipe 3 from one end of the pipe 3, and is brought to a position where the lid portion 304 abuts on the spacer 11. Next, the switch 111 is pushed by the foot to actuate the solenoid valve of the valve circuit 121, thereby actuating the air cylinder 70. As a result, the upper chuck plates 25, 26, 51 and 52 are rotated in the A direction, It is brought to the position shown in 7. In the position shown in FIG. 7, the recesses 35, 36, 60 and 61 are also provided with the ends 4 and 5 of the tubes 2 and 3, respectively, and the chucks 6 and 7 are piped by the aeroelastic force exerted by the air cylinder 70. The ends 4 and 5 of 2 and 3 are clamped and held. Since the thickness of the spacer 11 is D1 here, the distance between the end faces 9 and 10 of the tubes 2 and 3 thus holding the ends 4 and 5 is likewise set exactly at D1.

When the upper chuck plates 25, 26, 51 and 52 are brought to the position shown in FIG. 7, a detection signal is issued from the switch 115 for detecting the upper chuck plates 25, 26, 51 and 52, which causes the air cylinder 70 of the air cylinder 70 to pass through the valve circuit 121. The expansion / contraction operation in the B direction is stopped and the state is maintained, and the solenoid valve of the valve circuit 120 is operated to operate the rotary actuator 82. The spacers 11 are rotated in the C direction by the operation of the actuator 82, and are arranged at the downward rotation position as shown by the dotted line in FIG. In the initial rotation in the C direction, since the spacer 11 is in contact with the end faces 9 and 10, it is rotated while sliding on the end faces 9 and 10. When the spacer 11 is rotated to the downward rotation position in this way, a detection signal is issued from the switch 117 which detects this, whereby the actuator 82 is rotated via the valve circuit 120 in the C direction. While being stopped, the state is maintained, and the solenoid valve of the valve circuit 123 is operated to operate the rotary actuator 92. In this example, the operation of the actuator 92 is started by the generation of the detection signal of the switch 117. However, instead of this, the detection signal of the switch 115 may be generated. The operation start time of the actuator 92 may be set so that the heater 11 and the heating plate 13 do not collide with each other and the working time can be shortened.

The heating plate 13 is rotated in the E direction by the operation of the actuator 92, and is arranged in the right rotation position as shown by a dashed line in FIG. Since the heating plate 13 is narrower than the thickness D1 of the spacer 11 by the gaps D2 and D3, the heating plate 13 does not come into contact with the end faces 9 and 10 of the tubes 2 and 3 until the right rotation position. And both sides thereof are disposed between the chucks 6 and 7 with gaps D2 and D3 to the end faces 9 and 10, respectively. When the heating plate 13 is arranged in the right rotation position, a detection signal is issued from the switch 119 for detecting the heating plate 13, and thereby the rotation operation of the actuator 92 in the E direction with respect to the heating plate 13 is stopped via the valve circuit 123. Then, the state is maintained, and at the same time, the timer 113 starts the operation of measuring the heating time. When the heating plate 13 is thus arranged between the end faces 9 and 10, the end faces 9 and 10 are heated by the heating plate 13 for a predetermined time and melted. The melting start temperature of the tubes 2 and 3 of this example (the rising temperature of the endotherm accompanying the melting of the sample in the differential scanning calorimeter) is 275 ° C., and therefore the end surface 9 and 10. More specifically, the regions from the end faces 9 and 10 to about 0.5 mm in the axial direction are heated and melted. When the set time of 45 seconds elapses from the heating and melting condition, the timer 113 outputs a time-completion signal, which causes the electromagnetic valve of the valve circuit 123 to operate again and the rotary actuator 92 to operate. .. Due to this operation of the actuator 92, the heating plate 13 starts to rotate in the opposite direction to the above, and the heating plate 13 is arranged between the chucks 6 and 7. Thereafter, the heating plate 13 is rotated by the actuator 92 to the left rotation position shown in FIG. 2, and when a detection signal is issued from the switch 118 for detecting this, the actuator 92 is transmitted via the valve circuit 123. The rotation of the heating plate 13 in the E direction is stopped and the state is maintained.

On the other hand, the detection signal from the switch 118 separately activates the solenoid valve 108 of the valve circuit 106 and the driving device 331, and at the same time, starts the operation of measuring the pressure bonding time of the timer 113. By the operation of the solenoid valve 108, the air cylinder 101 moves the moving table 45 in the F direction so as to bring the chuck 7 closer to the chuck 6, so that the tube 3 clamped by the chuck 7 is brought closer to the tube 2 and finally heated and melted. The end face 10 thus formed is also pressure-bonded to the end face 9 which is also heated and melted. During this pressure bonding, even if the vicinity of the heated and melted end faces 9 and 10 is crushed, the pressure bonding force is accurately kept constant by the pressure reducing valve 107 of the valve circuit 106. The driving device 331 first drives the pinch roller 330 to slightly move the tubular body 301 to the predetermined position shown in FIG. 1, and at the same time, a predetermined amount of pressurized air is supplied to the inside 306. Its outer surface 315 is pressed against the inner surfaces 316 of the tubes 2 and 3, thus preventing the formation of beads during crimping as previously described. It should be noted that the time from the placement of the heating plate 13 outside the chucks 6 and 7 to the pressing operation is considerably high at the melting start temperature of the tubes 2 and 3 of 275 ° C., and there is a risk that the tubes 2 and 3 may be cooled immediately. Therefore, it is required to be extremely short, which is about 0.5 seconds in this example, but it is preferable to make this as short as possible.

In order to reduce the above-mentioned elapsed time of 0.5 seconds, a heating plate having a cavity smaller than the inner diameters of the pipes 2 and 3 is formed in the center, and the heating plate is halved at the center of the plate. Are preferably used. When this heating plate is used, the tubular body 301 can be preliminarily installed at a predetermined position shown in FIG. 1 through the cavity of the heating plate during the heating process, and the tubular body 301 can be inflated when heating is completed. That is, it is possible to omit the movement of the cylindrical body 301 to the predetermined position by the above-mentioned pinch roller 330. At this time, the divided heating plates are rotated in opposite directions.

When the crimping time set corresponding to the completion of crimping and the complete cooling of the welded portion, 20 seconds in this example, the timer 113 again issues a timing complete signal, which causes The solenoid valve of the circuit 121 and the drive device 331 are operated, and the solenoid valve 108 of the valve circuit 106 is also activated with a slight delay, whereby the air cylinder 70 causes the upper chuck plates 25, 26, 51 and 52 to rotate in the A direction. For the first time, the clamped state with respect to the tubes 4 and 5 is released, the moving table 45 is moved in the F direction so that the chuck 7 is separated from the chuck 6 by the air cylinder 101, and the upper chuck plates 25, 26, 51 and 52 are moved to the positions shown in FIG. When the air cylinder 70 is brought to the pinch release position shown in FIG. 1, the operation of the air cylinder 70 is stopped via the valve circuit 121 by the detection signal from the switch 114 which detects this. The upper chuck plates 25, 26, 51 and 52 are held in that position, the moving table 45 is brought to the position shown in FIG. 3 and held in that position, and the tubular body is operated by the drive device 331. While 301 is reduced, the air supply / exhaust pipe 311 is moved and the tubular body 301 is pulled out from the pipe 3. After the upper chuck plates 25, 26, 51 and 52 are brought to the unclamped position shown in FIG. 2, the butt welded tubes 2 and 3 are manually removed from the recesses 30, 31, 55 and 56. Finally, when the switch 112 is pressed, the actuator 82 is operated via the valve circuit 120 to rotate the spacer 11 in the C direction, and the spacer 11 is arranged at the upper rotation position shown by the solid line in FIG. The operation of the actuator 82 is stopped via the valve circuit 120 in response to the detection signal from the switch 116, and the spacer 11 is held in the upper rotation position. Thereafter, new pipes 1 and 2 to be butt-welded are placed on the chucks 6 and 7, and the above operation is repeated.

By the way, in the above-mentioned specific example, the vicinity of the end faces 9 and 10 of the tubes 2 and 3 is exposed to the outside during heating and crimping. As a result, the end faces 9 and 10 and the vicinity thereof may not be uniformly heated, and further, the heating plate 13 may be rapidly cooled after the heating plate 13 is removed. Therefore, as shown in FIG. 8, a sealing device 200 for sealing around the end surfaces 9 and 10 of the pair of tubes 2 and 3 heated by the heating plate 13 is provided on the pair of chucks 6 and 7 and the butt welding apparatus of the present invention is provided. May be formed. The sealing device 200 includes half outer cylinders 205, 206, 207 having semi-annular ends 201, 202, 203 and 204 fixed to opposite side surfaces of the lower chuck plates 22 and 46 and the upper chuck plates 26 and 51, respectively. And 208, half outer cylinders 209, 210, 211 and 212 movably arranged inside the half outer cylinders 205, 206, 207 and 208 in the axial direction, that is, the G direction, and a coil spring 213. , 214, 215, and 216, and the engaging collar portions 220, 221, 222, and 223 of the half-divided inner cylinders 209, 210, 211, and 212 have half-divided outer cylinders 205, 206. , 207 and 208 are engaged with the engaging collars 224, 225, 226 and 227, respectively, and are retained by the half outer cylinders 205, 206, 207 and 208. The coil springs 215 and 213 arranged between the upper and lower chuck plates 26 and 22 and the half-divided inner cylinders 211 and 209, respectively, are the semi-annular end surfaces 230 of the half-divided inner cylinders 211 and 209. The half inner cylinders 211 and 209 are elastically urged toward the chuck 7 side so that 231 is slidable on one side surface 232 of the heating plate 13 and is brought into airtight press contact, and the upper and lower sides. Coil springs 216 and 214 arranged between the chuck plates 51 and 46 and the half-divided inner cylinders 212 and 210 respectively heat the semi-annular end faces 234 and 235 of the half-divided inner cylinders 212 and 210. It is slidable on the other side surface 236 of the plate 13 and elastically urges the half-divided inner cylinders 212 and 210 toward the chuck 6 so as to press-contact airtightly. When the heating plate 13 is not arranged between the both end surfaces 9 and 10, it is biased by the coil springs 215, 213, 216 and 214 to form the half inner cylinders 209 and 211 and the half inner cylinder 210. And 212, and the semi-annular end faces 230 and 231 hermetically contact the corresponding semi-annular end faces 234 and 235. Therefore, the heating plate 13 is rotated so that the contact surfaces of the semi-annular end surfaces 230 and 231 and the corresponding semi-annular end surfaces 234 and 235 are easily pushed open to be disposed between the end surfaces 9 and 10 of the tubes 2 and 3. As described above, the outer edge 237 of the heating plate 13 has a taper guide surface 238, and the semi-annular end surfaces 231, 235, 230 and 234 of the half inner cylinders 209, 210, 211 and 212 have the same taper guide surface 238. A taper guide surface (not shown) is formed. Further, a taper guide surface is formed for the spacer 11 for the same purpose.

When such a sealing device 200 is provided, the periphery of the end faces 9 and 10 is isolated and sealed from the outside, so that heating of the heating plate 13 in the vicinity of the end faces 9 and 10 causes a heating rise air flow or The end faces 9 and 10 and their vicinity can be uniformly heated without being disturbed by the air flow due to other causes, and after the end faces 9 and 10 are heated and melted, the heating plate 13 is placed between the end faces 9 and 10. As a result of the airtight contact between the semi-annular end faces 230 and 231 and the semi-annular end faces 234 and 235, the surroundings of the end faces 9 and 10 are also isolated and sealed from the outside even in this state. It is also possible to avoid an inconvenient situation in which the vicinity of the end faces 9 and 10 that are heated and melted after the heating plate 13 is removed is cooled more rapidly than expected. Further, this sealing device 200 has the effect of suppressing or flattening the beads formed outside the joint between the pipes 2 and 3, and the bead inside the joint is cooled slowly. Therefore, the height tends to be suppressed. The effect of the sealing device 200 on bead formation becomes more effective and preferable by using it in combination with the bead generation preventing device 300.

The sealing device 200 is configured such that when the coil springs 213, 214, 215, and 216 are most elastically (contracted) in the pressure contact step, the springs do not return afterwards so that the respective stoppers work. Preferably. The heating step in this case is performed by rotating the heating plate 13 to the heating position and then releasing the stopper.

Further, in the above description, the vicinity of the end faces 9 and 10 is heated by the heating plate 13 having the flat side surfaces 232 and 236. However, as shown in FIG. In the case of forming bevels 252 and 253 having a so-called groove angle H on 251 and minimizing the bead generated on the inner surfaces 250 and 251, the groove was inclined similarly to the groove angle H. The heating plate 13 may be formed by providing annular protrusions 256 and 257 having annular outer peripheral surfaces 254 and 255 on the side surfaces 232 and 236, respectively. When the end faces 9 and 10 are heated by the heating plate 13 having the annular protrusions 256 and 257, the portions of the grooves 252 and 253 can be uniformly heated and melted, so that the groove angle H can be freely selected up to a large angle. In addition, since the groove surfaces 252 and 253 are sufficiently melted and wet, the beads flow and the beads generated on the inner surfaces 250 and 251 can be minimized. The heating plate 13 having the annular projections 256 and 257 may be applied to the tubes 2 and 3 having no such grooves 252 and 253.

Further, as shown in FIG. 10, the half attachments 271 and 272 are fitted in the recesses 35 and 30, respectively, and the upper and lower chuck plates 25 and 21 (the same applies to other upper and lower chuck plates). ) Via its flanges 273 and 274, and is detachably attached by means of a countersunk screw 275 or the like, and the ends of the pipes to be butt-welded are clamped via the recesses 276 and 277 of the half attachments 271 and 272. Is also good. Therefore, if a large number of half attachments 271 and 272 having the recesses 276 and 277 corresponding to the outer diameters of various pipes to be butt-welded are prepared, the half divisions without replacing the chucks 6 and 7 are performed. Butt welding can be readily performed on tubes of various outer diameters by simply replacing attachments 271 and 272.

In the butt welding apparatus 1 as described above, in addition to the effect of the bead generation preventing apparatus 300, the distance between the end faces of the pipe to be further heated and melted is always made constant by the spacer in advance, and this constant end face is fixed. Since both end faces of the synthetic resin pipe are uniformly heated and melted by the heating plates arranged in non-contact with each other, there is no fear of bending or deformation of the heating / melting part that may occur when removing the heating plate. In addition, it is possible to minimize the generation of beads and, in addition, the risk of deterioration due to oxidation heat is extremely small. Further, as a result of being able to automatically and continuously perform butt welding, the working time can be shortened.

The bead generation preventing device of the present invention is not limited to the one applied to the butt welding device 1 as described above. For example, a heating plate may be brought into contact with the outer surface or the end surface of the tube or may be heated with hot air. It may also be applied to a butt welding apparatus that heats and melts in a non-contact manner.

[0048]

[Effect of the device]

 As described above, since the bead generation preventing device of the present invention has the flexible tubular body, it is extremely easy to mount on the pipe to be butt-welded and has a soft contact, and the pre-heating It is not necessary to make contact with the inner surface of the pipe, and the cylindrical body can be expanded after heating and melting, and the end surface of the pipe can be uniformly heated and melted. There may be no risk of parts being created. Also, if the one that comes into contact with and presses against the inner surface of the pipe is made into an expandable and contractible tubular body, it can be used for butt welding of various pipes having different inner diameters, and furthermore, a small undulation on the inner surface of the pipe is possible. Even if there is, the outer surface of the tubular body can be pressed correspondingly to the inner surface of the tube, and as a result, bead formation can be more preferably prevented. Further, in the bead generation preventing device, since the flexible tubular body is simply inflated by the pressurized air, the tubular body can be extremely easily fitted along the inner surface of the pipe.

[Submission date] August 3, 1992

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

[Means for Solving the Problems]

According to the present invention, the above-described object is a bead generation preventing device used in a butt welding device for synthetic resin pipes, which includes a long air supply / discharge pipe and a flexible tube arranged at one end thereof. The air supply / discharge pipe is opened inside the tubular body at the one end, and the tubular body is supplied / discharged from an air source connected to the other end of the air supply / discharge pipe. This is accomplished by a bead prevention device that expands or contracts with air.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Further, according to the present invention, the above-mentioned object is used by arranging a pair of chucks for sandwiching respective ends of a pair of synthetic resin tubes to be welded, and between the chucks. A movable spacer that sets the end face distance, a movable heating plate that is placed with a gap between the end faces of the pipe whose end face distance is set to a predetermined value, and heats both end faces in a non-contact state, and this heating plate at both ends. A heating plate moving device that moves between the surfaces and the outside thereof, and a chuck moving device that moves at least one of the pair of chucks and presses the end faces melted and heated by the heating plate with a predetermined pressure. A butt welding device for synthetic resin pipes, comprising a bead generation prevention device for preventing the generation of beads on the inner surfaces of the pair of pipes in this pressure welding, the bead generation prevention device being inserted into the interior of the pair of pipes. It is removable And Te and long air supply and discharge line, which comprises a flexible tubular body that is disposed at one end, the air supply PIPE is open to the cylindrical body portion at the first end The tubular body is achieved by a butt welding device for a synthetic resin pipe that is expanded or contracted by the air supplied and discharged from an air source connected to the other end of the air supply and discharge pipe .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

In the embodiment shown in FIG. 1, the tubular body 301 is arranged at one end of the air supply / exhaust pipe 311 and is fixed and supported at one point 332 thereof via the lid 305. Further, in the above-described modification in which the air supply / exhaust pipe 311 also serves as the bridging member 308, the tubular body 301 is fixed at the two end portions of the air supply / exhaust pipe 311 via the lid portions 304 and 305. And is supported. In the case of the tubular body 301 in which the tubular body 301 and the lids 304 and 305 described above are integrally formed of the same material to have a balloon shape, the balloon has the air supply / exhaust pipe 311 as in the modified example. Preferably, it is fixed and supported at two points at one end. This is because in the two-point support, when the inner space 306 is pressurized to inflate the balloon, the inflation in the length direction is suppressed. At this time, a plug for sealing is provided at one end 310 of the air supply / exhaust pipe 311 if necessary.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

Incidentally, the sealing device 200, as does not return thereafter spring when the coil spring 213, 214, 215 and 216 are most repression (contraction), each of the coil springs or corresponding to that half the inner tubular member Alternatively, a stopper (not shown) may be used . In this case, the sealing device 200 is in a state in which the spring is compressed and the stopper is applied until the heating process or the process before the pressure contact process (the semi-annular end faces 230, 231, 234 and 235 are separated from the heating plate 13 in FIG. 8). position) and leave, a subsequent step to release the stopper just before the immediately pivoted the heating plate 13 to the heating position location or bonding step is performed.

[Submission date] August 4, 1992

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

[Means for Solving the Problems]

According to the present invention, the above-described object is a bead generation preventing device used in a butt welding device for synthetic resin pipes, which includes a long air supply / discharge pipe and a flexible tube arranged at one end thereof. The air supply / discharge pipe is opened inside the tubular body at the one end, and the tubular body is supplied / discharged from an air source connected to the other end of the air supply / discharge pipe. This is accomplished by a bead prevention device that expands or contracts with air.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Further, according to the present invention, the above-mentioned object is used by arranging a pair of chucks for sandwiching respective ends of a pair of synthetic resin tubes to be welded, and between the chucks. A movable spacer that sets the end face distance, a movable heating plate that is placed with a gap between the end faces of the pipe whose end face distance is set to a predetermined value, and heats both end faces in a non-contact state. A heating plate moving device that moves between the surfaces and the outside thereof, and a chuck moving device that moves at least one of the pair of chucks and presses the end faces melted and heated by the heating plate with a predetermined pressure. A butt welding device for synthetic resin pipes, comprising a bead generation preventing device for preventing the generation of beads on the inner surfaces of the pair of pipes in this pressure welding, the bead generation preventing device being inserted into the inside of the pair of pipes. It is removable And Te and long air supply and discharge line, which comprises a flexible tubular body that is disposed at one end, the air supply PIPE is open to the cylindrical body portion at the first end The tubular body is achieved by a butt welding device for a synthetic resin pipe that is expanded or contracted by the air supplied and discharged from an air source connected to the other end of the air supply and discharge pipe .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

In the embodiment shown in FIG. 1, the tubular body 301 is arranged at one end of the air supply / exhaust pipe 311 and is fixed and supported at one point 332 thereof via the lid 305. Further, in the above-described modification in which the air supply / exhaust pipe 311 also serves as the bridging member 308, the tubular body 301 is fixed at the two ends of the one end of the air supply / exhaust pipe 311 via the lids 304 and 305. And is supported. In the case of the tubular body 301 in which the tubular body 301 and the lids 304 and 305 described above are integrally formed of the same material to have a balloon shape, the balloon has the air supply / exhaust pipe 311 as in the modified example. Preferably, it is fixed and supported at two points at one end. This is because in the two-point support, when the inner space 306 is pressurized to inflate the balloon, the inflation in the length direction is suppressed. At this time, a plug for sealing is provided at one end 310 of the air supply / exhaust pipe 311 if necessary.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction content]

Incidentally, the sealing device 200, as does not return thereafter spring when the coil spring 213, 214, 215 and 216 are most repression (contraction), each of the coil springs or corresponding to that half the inner tubular member Alternatively, a stopper (not shown) may be used . In this case, the sealing device 200 is in a state in which the spring is compressed and the stopper is applied until the heating process or the process before the pressure contact process (the semi-annular end faces 230, 231, 234 and 235 are separated from the heating plate 13 in FIG. 8). position) and leave, a subsequent step to release the stopper just before the immediately pivoted the heating plate 13 to the heating position location or bonding step is performed.

[Brief description of drawings]

1 is a cross-sectional view of a preferred embodiment of the present invention.

FIG. 2 is a side view of a preferred embodiment of the present invention applied to a butt welding device.

FIG. 3 is a front view of the specific example shown in FIG.

FIG. 4 is a partial plan view of the specific example shown in FIG.

5 is a block diagram of a control system of the specific example shown in FIG.

FIG. 6 is a partial detailed explanatory diagram of the valve circuit of the specific example shown in FIG.

FIG. 7 is an operation explanatory diagram of the specific example shown in FIG. 2;

FIG. 8 is a partial front view of another preferable specific example of the butt welding apparatus.

FIG. 9 is a partial front view of still another preferable example of the butt welding apparatus.

FIG. 10 is a partial perspective view of still another preferred example of the butt welding apparatus.

[Explanation of symbols]

 300 Bead Generation Prevention Device 301 Cylindrical Objects 304, 305 Lid 311 Compressed Air Conduit

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 3, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Item name to be amended] Scope of utility model registration request

[Correction method] Change

[Correction content]

[Scope of utility model registration request]

9. The butt welding apparatus according to claim 4, wherein the air supply / exhaust pipe has flexibility. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 4, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Item name to be amended] Scope of utility model registration request

[Correction method] Change

[Correction content]

[Scope of utility model registration request]

Claims (9)

[Scope of utility model registration request] 1. A bead generation preventing device used in a butt welding device for a synthetic resin pipe, comprising a long air supply / discharge pipe, a flexible tubular body disposed at one end thereof, and others. An air source connected to the end, the air supply / exhaust pipe is opened inside the tubular body at the one end, and the tubular body is expanded or contracted by the air supplied from the air source. Bead prevention device. 2. The bead generation preventing apparatus according to claim 1, wherein the tubular body is made of heat resistant rubber, preferably silicon rubber or fluororubber. 3. The bead generation preventing device according to claim 1, wherein the air supply / exhaust pipe has flexibility. 4. A pair of chucks for sandwiching respective ends of a pair of synthetic resin tubes to be welded, and a movable spacer used between the chucks for setting an end face distance of the pair of tubes. And a movable heating plate which is arranged with a gap between the end faces of the pipe whose end face distance is set to a predetermined value to heat both end faces in a non-contact state, and the heating plate is moved between both end faces and outside thereof. A heating plate moving device for moving, and a chuck moving device for moving at least one of the pair of chucks to press the end faces heated and melted by the heating plate under a predetermined pressure, and the inner surfaces of the pair of pipes in this pressing. A butt welding device for synthetic resin pipes, comprising a bead generation preventing device for preventing bead generation, wherein the bead generation preventing device is a long air supply / discharge device that can be inserted into and removed from a pair of pipes. Tube and one end A flexible tubular body disposed in
And an air source connected to the other end, the air supply and discharge pipe is opened inside the tubular body at the one end,
A butt welding device for synthetic resin pipes in which a tubular body is expanded or contracted by air supplied and exhausted from an air source. 5. A chuck drive device that switches a chuck between a pair of tubes between a clamped state and a clamped state.
The butt welding apparatus according to claim 4, further comprising a spacer moving device that moves the spacer between the pair of chucks and outside thereof. 6. The heating plate moving device comprises a rotary actuator for rotating the heating plate to move the heating plate between the end faces of the pair of tubes facing each other and outward thereof.
Or the butt welding device according to 5. 7. The butt welding apparatus according to claim 4, wherein the pair of chucks are provided with a sealing device that seals the periphery of the end faces of the pair of tubes heated by the heating plate. 8. The butt welding apparatus according to claim 4, wherein the tubular portion is made of heat resistant rubber, preferably silicon rubber or fluororubber. 9. The butt welding apparatus according to claim 4, wherein the air supply / exhaust pipe has flexibility.