JPH09192889A - Internal clamp device provided with clearance filling means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous back bead of uniform height which is generated on an inner wall part of a steel tube after welding by inserting a filling backing strap in a cavity formed between end parts of adjacent backing straps when the backing strap of an expanding means is abutted on the inner wall of the steel tube. SOLUTION: A second actuator 13 to slidably move a filling backing strap 12 in the tubular length direction of a steel tube 20, and a first actuator 14 to elevate/lower the filling backing strap 12 to an inner wall surface of the steel tube 20 are slidably moved to press the V-shaped cavity formed by a copper backing strap 2 and an adjacent copper backing strap 2 against the inner wall of the steel tube 20 by the filling backing strap 12. At the same time, the filling backing strap 12 loaded on a slide plate is slidable moved in the tubular length direction of the steel tube 20 by the first actuator 13 to fit a trapezoidal tip part of the filling backing strap 12 to the V-shaped cavity. The V-shaped cavity generated by the copper backing straps 2 is filled through a series of simultaneous actions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to correct a manufacturing error in the inner diameter of a steel pipe when a steel pipe having a grooved end and a steel pipe are fixed from the inside of the pipe and the steel pipes are circumferentially welded from the outer periphery. The present invention relates to an internal clamp device that makes a back bead generated on an inner wall portion of a steel pipe after welding have a continuous and uniform height.

[0002]

2. Description of the Related Art Conventionally, when welding large-diameter steel pipes used to supply city gas, etc., the steel pipes whose ends are groove-processed are fixed from the inside using an internal clamp device. After that, circumferential welding is performed from the outer peripheral side of these steel pipes by an automatic welding device.

In such a conventional internal clamping device 1 as shown in FIG. 17, when the steel pipes 20 and 20 are butt-welded to each other, each of the steel pipes 20 is clamped by a clamp portion 9 as the plunger slides. After the internal pipe is expanded by the mechanism 21 and clamped, the annular pipes 52a and 52b of the wedge-shaped backing member 52 shown in FIG. Cutting is performed so that the directions form a slight angle, and further, backing is performed along the entire circumference of the inner surface of the butted portion of the steel pipes 20, 20 without gaps and welding is performed.

However, even if the steel pipes 20 and 20 are fixed to each other by the internal clamp device 1 and circumferential welding is performed, the steel pipe 20 has an allowable manufacturing error. The permissible error in this case is tolerated, and depending on the combination of the maximum value and the minimum value of this error, a large difference occurs in the inner diameter difference between steel pipes.)
Since there is a distance between the clamp portion 9 of the steel pipe 20 and the groove portion where welding is actually performed, if welding is performed without correcting this tolerance, welding is performed without proper centering work. It becomes processing. Further, the wedge-shaped backing member 52
Means that a plurality of annular dividing bodies 52a and 52b, which are divided in the circumferential direction so as to be in contact with each other in a wedge shape, perform backing with no gap over the entire circumference of the inner surface of the butted portion. Since the pressing surfaces for pressing the inner wall surfaces of the steel pipes 20, 20 of the bodies 52a, 52b are flat, the heights of the back bead formed by these pressing surfaces are not uniform.

Further, the pipe centering / straightening device of the internal clamp device disclosed in Japanese Patent Publication No. 52-22905 is a fan-shaped back for forming the centering and straightening of the steel pipe on the inner surface of the steel pipe on the outer ring side. By combining a plurality of contact plates and a reverse fan type backing plate that forms the inner ring side shape into the inner surface shape of the steel pipe, it is possible to back up the entire inner surface of the abutting portion of the steel pipe without a gap. However, the plungers that operate each backing plate are independent of each other, and since the steps are created between the backing plates to press the steel pipe for centering and straightening, the manufacturing tolerance of the steel pipe is the maximum. In the case of the minimum combination, the back bead formed is continuous, but the height is not uniform.

The back bead formed when the welding process is performed in these states not only causes turbulence in the fluid flowing in the steel pipe, but also causes welding stress near the welded portion of the steel pipe after welding. Is also a factor that causes distortion in the inner and outer diameters of the steel pipe by causing a large number of concentrating points, and this strain of the steel pipe is a cause of harmful phenomena such as brittle fracture and fatigue fracture of the steel pipe itself, and stress corrosion. May be.

[0007]

In order to eliminate these factors, conventionally, the back bead formed on the inner wall of the welded portion at a non-uniform height is repaired by a grinder or the like, and stress concentration is removed. In order to do so, work such as shot peening is required, and the time spent for these operations is the same as or longer than the work time required for welding work for large diameter steel pipes such as gas distribution mains. Was spending time on.

The present invention has been made to solve the above-mentioned drawbacks, and when a copper backing plate which is a curved backing member of an internal clamp device is circumferentially welded to each other with manufacturing tolerances. In addition, the inner diameters of the steel pipes are corrected and fixed, and the back bead generated on the inner wall of the steel pipe after circumferential welding is made to have a uniform height. In order to make the beads continuous,
It is an object of the present invention to provide an internal clamping device equipped with a gap filling means that does not require adjustment work required for the height of the back bead, etc., and is unlikely to cause concentration of welding stress near the welded portion. It is a thing.

[0009]

In order to achieve these objects, the present invention is characterized by a means for solving the problems. As a characteristic of the means for solving the problems, steel pipes whose ends are groove-processed are fixed from the inside of the pipes, In the internal clamp device for welding,
A plurality of curved backing members are arranged reciprocally on the head of the plunger on the circumference of the internal clamp device so as to reciprocate freely, and the expanding means for correcting the inner diameter of the steel pipe, and the expanding means of the expanding means. When the backing member comes into contact with the inner wall of the steel pipe, the gap formed between the ends of the adjacent backing members is filled, and the backing member is made continuous by inserting the backing member. It consists of and.

Next, a characteristic of the expanding means is that the backing member is fitted through the backing metal holders mounted on the heads of a plurality of reciprocating plungers. .

Further, as a characteristic of the backing member,
The outer peripheral shape is a curved shape that equally divides the inner peripheral shape of the steel pipe, and both ends thereof are formed with a predetermined angle, and the vicinity of the central portion is screwed and fixed to the stopper metal holder of the one plunger. It is configured such that the pad holder is slidably loosely fitted in the concave groove of the pad holder formed in the concave shape of the head of the plunger located on the left and right of the plunger screwed and fixed.

The features of the gap filling means include:
When the backing member comes into contact with the inner wall surface of the steel pipe, a C-shaped gap formed between the backing member and the backing member adjacent to the backing member is filled, and the backing plate of the backing member is filled. The first actuator that freely slides in the direction and the second actuator that freely slides in the pipe length direction are configured to be inserted and compensated by simultaneous operation.

Further, a swinging mechanism for pivotally supporting the second actuator of the gap filling means on the head of the first actuator, and a second actuator for freely swinging by the swinging mechanism. The feature of the rotation restricting mechanism for restricting the rotation of the guide rod is that it is screwed and fixed to the main body of the internal clamp device, and the guide rod bracket for erected the guide rod and the first actuator are mounted. The guide rod is inserted into the guide hole of the bracket so that the guide rod can be freely fitted, and the fitting play is restricted at both edges of the guide hole. Accordingly, the rotation of the swinging mechanism is regulated.

Further, the backing member is characterized in that both side portions near both end portions thereof are sandwiched by a protective member which is a plate material and a guide pin for externally fitting a guide pin collar is sandwiched between the two members. A backing member protection mechanism is provided for restricting the sliding of both ends of the backing member by a backing metal holder which is a through hole of the guide pin and which forms a long guide groove.

Finally, the characteristic of the backing member is that a long axis bolt is projected and screwed and fixed on the bottom surface near both ends thereof,
The projecting long-axis bolt penetrates the long hole formed in the concave groove of the pad holder to protect the backing member that restricts sliding in the concave groove of the pad holder. It is to have a structure having a mechanism.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an internal clamp device having a gap filling means of the present invention will be described with reference to the drawings. It is to be noted that, of the reference numerals used in the description of the conventional example and the reference numerals assigned to the specific items of the present invention, those denoted by the same reference numerals have the same contents, and thus the description thereof will be omitted.

FIG. 1 is a side view showing an embodiment of an internal clamp device having a gap filling means according to the present invention, and FIG. 2 is a front view of the internal clamp device shown in FIG. 1 in a steel pipe. 3 is a partially broken explanatory view showing an enlarged main part of a portion A of FIG. 1, and FIG. 4 is an operation in a state where welding is performed after the inner peripheral shape of the steel pipe is corrected by the copper backing metal of FIG. FIG. 5 is an explanatory view, FIG. 5 is an operation explanatory view of the trapezoidal supplemental backing plate of FIG. 4, FIG. 6 is an enlarged view of a B portion of FIG. 2, and FIG. 7 is a copper near the C portion of FIG. It is a perspective view explaining a backing metal.

In the drawings, reference numeral 1 indicates an internal clamp device, reference numeral 2 indicates a copper backing metal which is a backing member, and reference numeral 3 fits and holds the curved copper backing metal 2. Reference numeral 4 represents a backing metal holder, reference numeral 4 represents a plunger that slides up and down the backing metal holder 3, and reference numeral 12 represents a backing backing metal which is a backing backing member of the gap filling means.
Reference numeral 10 denotes a welded portion where the groove portions of the steel pipes 20 and 20 are welded, and reference numeral 10a denotes a back bead in circumferential welding of the steel pipes 20 and 20.

First, the assembled state of the copper backing plate 2 will be described. On the outer circumference of the main body of the internal clamping device 1, a plurality of plungers 4 for expanding the steel pipes 20 and 20 are formed on the same circumference. Is provided so that it can be freely expanded and contracted in the outer peripheral direction, and a stopper metal holder 3 having a concave groove 3z having a concave sectional shape is formed on the heads of the plungers 4 below the center line of the abutting portion of the steel pipes 20, 20. Are screwed and fixed by the mounting bolts 3y so as to correspond to.

In this embodiment, as shown in FIG. 2, twelve plungers 4 are arranged on the outer circumference of the internal clamp device 1, and three plungers (4a, 4b, 4c) adjacent to each other in the left and right direction are arranged. 4) as a set
The copper backing plate 2 is a steel pipe 20,
The inner peripheral diameter of 20 is divided into four equal parts, which are arcuate and curved. As shown in FIG. 7, the copper backing plate 2 is fitted and arranged in the concave groove 3z of the metal plate holder 3 which is screwed and fixed to the heads of the plungers 4a, 4b and 4c. The plunger 4b located at the center of the plungers 4a, 4b, 4c has its arcuate center portion screwed and fixed by a mounting bolt 2b. It should be noted that, instead of the mounting bolt 2b, a drilling hole indicated by reference numeral 3b in this figure is formed on one side surface of the backing metal holder 3, and the fixing method of penetrating and fixing to the copper backing metal 2 with the bolt 3c is the same as the above. It becomes the form of.

The copper backing plate 2 is generally made of a copper alloy, and has a cross-sectional shape that fits into the concave groove 3z of the backing plate holder 3 and that of the inner wall of the welded steel pipe 20. In addition to being formed in an arc shape that engages with each other, the edge portions at both ends are formed with tapered portions 2a having a predetermined angle shown in FIG. 5B described later.

Next, the fitting relationship between the recessed groove 3z of the backing metal holder 3 and the copper backing metal 2 will be described. The copper backing metal 2 is completely fitted in the recessed groove 3z of the backing metal holder 3. And the copper backing metal 2 of each curved shape.
The circular arc-shaped central portion of the plunger is screwed and fixed to the stopper holder 3 of the plunger 4b arranged at the central portion of the plungers 4a, 4b, 4c, which is a set of three as described above, by the mounting bolt 2b. 4b of the metal plate holder 3 disposed on the left and right of the plunger 4a, 4c of the metal plate holder 3
In each concave groove 3z of the
Copper backing plate 2 which is in a fitted state with the rise of 4b and 4c
The both end portions of the are configured to be freely slidable.

With this configuration, when each of the plungers 4a, 4b, 4c extends, both ends of the copper backing plate 2 in the concave groove 3z of the backing plate holder 3 slide with the expansion. To do. When the steel pipes 20, 20 are centered or the inner diameters of the steel pipes 20, 20 are corrected, the plungers 4a, 4b, 4c are lifted to move the copper backing plate 2 to the steel pipe 20 through the plate holder 3. Press the inner wall, steel pipe 20,
20 The steel pipes 20 and 2 acting on the location where there is mutual error
The steel pipe 20 after welding has been corrected to have the same inner diameter.
The back bead 10a formed on the inner wall of the is made uniform in height.

On the other hand, when the plungers 4a, 4b, 4c expand the steel pipes 20, 20 internally, a gap is created between the copper backing plates 2 adjacent to each other. This gap is the edge of the copper backing plate 2. The tapered portion 2a shown in FIG. 5 (b) forms a V-shaped gap. The void filling means fills the gap in the V shape, and the backing metal 12 for filling the voids has the shape of the copper backing metal 2, 2.
It is formed in a trapezoidal shape that engages with a V-shaped gap formed by the tapered portions 2a and 2a at the edge of the end.

The trapezoidal backing metal 12 is shown in detail in FIG.
It is screwed and fixed to a by bolts 12c and 12d, and a slide plate 15 is arranged on the bottom thereof. This slide plate 15 smoothly inserts the filling backing plate 12 into the C-shaped gap by the reciprocating movement of the second actuator 13 of the gap filling means for sliding the filling backing plate 12 in the pipe length direction of the steel pipe 20. It has a function to make it. The slide plate 15 is screwed and fixed to a bracket 13a located at a lower portion with a bolt 15a, and the bottom portion of the bracket 13a is provided with a first gap filling means for allowing the steel pipe 20 to slide in the pipe wall direction. An actuator 14 is arranged, and the rising back of the first actuator 14 presses the supplementary backing plate 12 inserted into the V-shaped gap against the inner wall of the steel pipe.

The function of the gap filling means for filling the square-shaped gap between the copper backing plate 2 and the adjacent copper backing plate 2 by the filling backing plate 12 will be described below. First, the second actuator 13 that slides the supplementary backing plate 12 in the pipe length direction of the steel pipes 20, 20 and the first actuator 14 that raises and lowers the supplemental backing plate 12 to the inner wall surface of the steel pipes 20, 20 are slid. When the copper backing metal 2 and the adjacent copper backing metal 2 are operated, the gap between the copper backing metal 2 and the C-shaped backing metal 12 is pressed against the inner walls of the steel pipes 20, 20. The supplementary backing plate 12 placed on the slide plate 15 at the same time as this pressing causes the steel pipe 2 to move by the first actuator 13.
The trapezoidal tip portion of the supplementary backing plate 12 is fitted into the above-mentioned V-shaped gap by sliding in the direction of 0 of the pipe. By performing such a series of operations at the same time, the C-shaped gap generated by the copper backing plate 2 is compensated for, and continuous back-beat beats can be formed.

11 to 13 show a second embodiment of the gap filling means. The gap filling means is
When the V-shaped gap is filled by the gap filling means of the above-mentioned embodiment, the contact surface 12 of the trapezoidal filling backing plate 12 is filled.
Depending on the shape of the V-shaped gap formed by the taper portion 2a of the copper backing plate 2, b may not sometimes be in a close contact state.

To cope with such a case, there is an embodiment shown in FIGS. 11 to 13, and FIG. 11 shows a side view of the second embodiment of the gap filling means.
Shows an explanatory diagram showing the state before the operation of the gap filling means, (b) shows an explanatory view showing a state after the operation, FIG. 12 shows a plan view of FIG. 11, (a) of this figure shows before the operation, and (b) shows the operation. Each of the latter states is shown, and FIG. 13 is a partially cutaway side view of the main part of FIG.

In the figure, a supplementary backing plate 12 is attached to a steel pipe 20.
The first actuator 14 to be slid to the inner wall surface of the first actuator 14 is screwed and fixed to the main body of the internal clamp device 1 by a bolt 17, and the bracket 13a is attached to the head of the first actuator 14 as shown in FIG. ), A swinging mechanism using a bolt 18 is provided so that the Z direction can be freely rotated. On the other hand, this swinging mechanism is restricted in its rotation by a rotation restricting mechanism that restricts it within a range of rotation within the angle of the square-shaped gap formed by the tapered portion 2a of the copper backing plate 2. However, the rotation restricting mechanism includes a guide rod bracket 22 screwed and fixed to the main body of the internal clamp device 1 by a bolt 19, a guide rod 23 standing on the guide rod bracket 22, and the bracket 13 described above.
The guide hole 13b is an elongated hole formed at the edge of a.

The second of the space filling means having such a structure
The operation of the first embodiment will be described. Like the above-described example of the embodiment of the gap filling means, the steel pipe 2 which has been groove processed first is used.
The plunger 4 extends on the inner walls of the 0 and 20 and the copper backing plate 2 of the plate holder 3 attached to the head of the plunger 4 is brought into contact. In such a state, a gap is formed between the taper portions 2a of the adjacent copper backing plates 2, but the shape of the gap is formed by the taper portion 2a to have a trapezoidal shape.

Next, the first actuator 14 for moving up and down in the direction of the inner wall of the steel pipe 20 (Y direction in FIG. 11B).
Also, the second actuator 13 (X direction in FIG. 11B), which is slidable in the pipe length direction, extends substantially at the same time, and the insertion of the supplementary backing plate 12 into the gap is achieved. At this time, the respective gaps caused by the expansion of the plunger 4 may have different shapes depending on the flat shape due to the manufacturing tolerance of the steel pipe 20 to be expanded and corrected. There is a case where the contact surface 12b of the supplementary backing plate 12 and the taper portion 2a of the backing member 2 are not completely in contact with each other when being inserted into the space.

In such a case, the second actuator 13 attached to the head of the first actuator 14 is rotated by the bolt 18 of the swing mechanism ((b) of FIG. 12). The Z direction) is filled.
The rotation of the bracket 13a is limited to a predetermined rotation range, and the end portion of the guide rod 23 erected on the guide rod bracket 22 is provided in the long guide hole 13b formed at the edge of the bracket 13a. Is inserted and the rotation range is regulated.

The tapered portion 2a of the copper backing metal 2 is formed by the above-described embodiment of the void filling means or the second embodiment.
When the C-shaped gap generated between them is completed by the filling of the filling backing plate 12, the back bead 1 having a uniform height continuously.
0a is formed and circumferential welding is performed, and then the copper backing metal 2
Lower the plungers 4a, 4b, 4c of
The second actuator 13 and the first actuator 14 of the supplementary backing plate 12 return to the home position shown by reference numeral 16 in FIG. 4 or the state shown in FIG. 11 (a).

At this time, the copper backing metal 2 and the supplementary backing metal 12 which are pressed against the inner wall surface of the steel pipe 20 are the back bead 1
The molten welding material may adhere to the steel pipe 20 while being repeatedly welded to the contact surface with 0a. In such a case, the back bead 10a and the copper backing metal 2 and the supplementary backing metal 1
2 may not be able to be peeled off smoothly.

When the supplementary backing plate 12 is peeled off from the back bead 10a, an independent first actuator 14 is used.
Since it is lowered by the second actuator 13, the peeling from the back bead 10a is easy, but when lowering the curved copper backing plate 2, the backing bead holder 3 of the plunger 4b in the center part is lowered. Plungers 4a and 4c that fit near both ends because they are screwed and fixed only
With the copper backing metal 2 of FIG. When the plungers 4a and 4c are forced to descend, the vicinity of the end of the copper backing plate 2 may be distorted due to the lowering of the plungers 4a and 4c, and may even be damaged. Will shorten the life of the.

For the purpose of protecting the copper backing plate 2 from deformation due to strain near the end and wear and the like when both shoulders 2c contact the inner wall of the steel pipe 20, the end of the copper backing plate 2 is protected. A protection mechanism for the copper backing metal 2 is installed near the
An embodiment of this protection mechanism will be described below. FIG. 8 is a cross-sectional view for explaining the first embodiment of the protection mechanism for the copper backing plate 2, and FIG. 9 is a cross-sectional view showing a state where the copper backing plate 2 is peeled from the back bead 10a. FIG. 10A is a cross-sectional view of the copper backing plate 2 sandwiched by the protection members 5 along the line D-D in FIG. 8.

In these figures, a protection member 5 made of stainless steel is formed on both side surfaces near both ends of the copper backing plate 2 and has the same depth as the shoulder portion 2c of the copper backing plate 2 in which a concave groove 3z is formed. Hold the copper backing plate 2 with a backing plate and flatten the bolt 5a
The guide pin 6 is provided on the protective member 5 so as to project in the pipe length direction of the steel pipe 20. A guide pin collar 7 for protecting the guide pin 6 is externally fitted on the outer periphery of the guide pin 6, and further, a guide hole having a long hole, which is a through hole, is formed on both side surfaces of the pad holder 3. A groove 8 is formed, and in this guide groove 8, the guide pin 6 projecting from the protection member 5 is loosely fitted so as to freely slide.

Here, the operation of the copper backing plate 2 with the protective member 5 attached will be described. When the copper backing plate 2 after welding is separated from the back bead 10a, the plunger 4b is used.
In the backing metal holder 3, since the arcuate center portion of the copper backing metal 2 is screwed and fixed, peeling is easy. However, both ends of the copper backing metal 2 are guided inside the guide groove 8 as the plungers 4a and 4c descend.
Since the guide pin 6 is restricted to abut on the upper stop point of the concave portion of the concave portion, the guide pin 6 is interlocked with the plungers 4a and 4c, and is easily separated from the back bead 10a by the descending force of the strong plungers 4a and 4c. be able to.

When the plunger 4 expands the steel pipes 20, 20, the plunger 4 and the pad holder 3,
Furthermore, the backlash of the copper backing plate 2 and the steel pipe 20, 20
Due to elastic strain due to a large force when the pipe is expanded inside, the vicinity of both ends of the copper backing plate 2 easily contacts the inner wall surface of the steel pipe 20, and as a result, the narrow shoulder 2c of the copper backing plate 2 is Cause friction with the member. Therefore, on both side surfaces near both ends of the copper backing plate 2, a protection member 5 having a hardness higher than that of the copper backing plate 2, for example, stainless steel or the like, is screwed by bolts while sandwiching the copper backing plate 2. The outer edge 5b of the head is formed to have the same height as the shoulder 2c of the copper backing plate 2. By forming in this way, the head outer edge 5b of the protection member 5 comes into contact with the inner wall surface of the steel pipe 20 near both ends of the copper backing plate 2, and the copper backing plate 2
It is possible to prevent wear of the shoulder portion 2c.

Further, in performing the circumferential welding for forming the favorable back bead 10a, it is possible to form a concave groove portion on the outer peripheral surface of the copper backing plate 2 and to control the dimensions of both the shoulder portions 2c and the groove portion. This is an important issue, and if welding material is welded by repeated welding work and the height of the shoulder portion 2c is deformed, it causes a welding defect, but in the present invention, it can be suppressed to the minimum.

Next, a second embodiment of the protection mechanism for the copper backing plate 2 will be described below. FIG. 14 is a cross-sectional view of the main part for explaining the second embodiment of the protection mechanism, and FIG.
FIG. 16 is a cross-sectional view showing a state where the copper backing plate 2 is peeled off from the back bead 10a, and FIG. 16 is a partial perspective view showing a second embodiment of the protection mechanism for the copper backing plate 2. (B) of FIG. 14 is a cross-sectional view of the copper backing plate 2 sandwiched by the protection members 5 taken along the line EE of FIG. 14.

In these drawings, in the second embodiment of the protection mechanism for the copper backing plate 2, a long-axis bolt 30 is projected and screwed and fixed to the bottom surface near both ends of the copper backing plate 2. At the bottom of the concave groove 3z of the pad holder 3, there is formed an elongated hole 3a through which the projecting long-axis bolt 30 penetrates and can be slid freely. The sliding adjustment of the copper backing plate 2 in the concave groove 3z of the pad holder 3 is adjusted by adjusting the expansion and contraction of the bolt 30 penetrating the elongated hole 3a,
The same operation as that of the first embodiment of the protection mechanism is achieved.

[0043]

According to the present invention described above, the internal clamp device having the gap filling means has the following effects.

1) Even if the curved backing member of the internal clamp device circumferentially welds steel pipes having manufacturing tolerances when performing circumferential welding between grooved steel pipes. The inner diameters of the steel pipes can be corrected and fixed to each other, and the back bead generated on the inner wall of the steel pipe after the circumferential welding can be made uniform in height. 2) Further, the filling backing member of the internal clamp device can continuously form the back bead after welding in order to fill the gap formed by the backing member. 3) Furthermore, since the work of adjusting the height of the back bead is unnecessary by the backing member and the supplementary backing member, the concentration of welding stress is less likely to occur near the welded portion of the steel pipe. 4) It should be noted that a swinging mechanism that pivotally supports the second actuator of the gap filling means on the head of the first actuator, and a rotation of the second actuator that is rotatable by this swinging mechanism. By incorporating a rotation restricting mechanism for restricting motion, the guide bar standing on the guide bar bracket is inserted into the guide hole of the bracket so that it can be freely inserted,
The contact state between the backing member and the supplementary backing member becomes more dense, and the height adjustment of the back bead becomes unnecessary, and the concentration of welding stress in the vicinity of the welded portion of the steel pipe hardly occurs. 5) In addition, since the inner wall of the steel pipe and the end of the backing member are not directly in contact with each other by the protection mechanism such as the protection member sandwiched near the end of the backing member, the backing member is protected to prevent deformation. This has the effect of preventing it. 6) To attach the protection mechanism consisting of a protective member to the backing metal holder, fix a long shaft bolt to the bottom surface near both ends of this copper backing metal by screwing and fixing, and By penetrating through the elongated hole formed at the bottom, the sliding is made possible and the copper backing plate can be smoothly peeled off from the fixation by the back wave beat. 7) In addition, the protection mechanism including a protection member and the like is attached to the backing metal holder by sandwiching the copper backing metal with both sides of the backing metal near the both ends by the protection member projecting the guide pin for externally fitting the guide pin collar. Therefore, in order to regulate the sliding of both ends of the backing member by the backing plate holder that forms the guide groove of the guide pin, as in the case of the above-mentioned protection mechanism, the copper backing plate is prevented from being fixed by the back beating beat. Smooth peeling is possible. This is an effect.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of an internal clamp device provided with a gap filling means according to the present invention.

FIG. 2 is a front view of the internal clamp device shown in FIG. 1 in a steel pipe.

FIG. 3 is an explanatory diagram in which a main part of a part A in FIG. 1 is enlarged.

FIG. 4 is an operation explanatory view of a state where welding is performed after the inner peripheral shape of the steel pipe is corrected by the copper backing metal of FIG. 3;

5 is an operation explanatory view of the trapezoidal supplementary backing plate of FIG. 4;

FIG. 6 is an enlarged view of part B in FIG.

FIG. 7 is a perspective view illustrating a copper backing plate near the portion C in FIG.

FIG. 8 is a sectional view illustrating a first embodiment of a copper backing plate protection mechanism.

FIG. 9 is a cross-sectional view showing a state in which a copper backing strip is peeled from a back bead.

10 is a cross-sectional view of the copper backing plate, FIG. 10A is a cross-sectional view taken along the line DD of FIG. 8, and FIG. 10B is a cross-sectional view of the copper backing plate taken along the line EE of FIG. FIG.

FIG. 11 is a side view showing a second embodiment of the gap filling means, (a) is an operation explanatory diagram showing a state before the gap filling means is activated and (b) is a state after the operation.

FIG. 12 is a plan view of FIG. 11, in which (a) is an operation explanatory diagram showing a state before the operation and (b) a state after the operation.

13 is a partially cutaway side view of the main part of FIG.

FIG. 14 is a cross-sectional view of a main part for explaining a second embodiment of a protection mechanism.

FIG. 15 is a cross-sectional view showing a state in which the copper backing metal 2 is separated from the back bead 10a.

16 is a partial perspective view showing a second embodiment of the protection mechanism for the copper backing plate 2. FIG.

FIG. 17 is a side view of a conventional internal clamp device.

FIG. 18 is an operation explanatory view of a wedge-shaped backing member of a conventional internal clamp.

[Explanation of symbols]

 1 Internal Clamping Device 2 Copper Backing Plate 2a Tapered Part 2b Mounting Bolt 2c Shoulder Part 3 Caulking Holder 3a Elongated Hole 3b Drilling Hole 3c Bolt 3y Mounting Bolt 3z Recessed Groove 4 Plunger 5 Protective Member 5a Plate Bolt 5b Head Edge 6 Guide Pin 7 Guide Pin Collar 8 Guide Groove 9 Clamping Part 10 Welding Point 10a Back Wave Bead 12 Complementary Backing Plate 12a Bracket 12b Abutment Surface 12c Bolt 12d Bolt 13 Second Actuator 13a Bracket 13b Guide Hole 14 First Actuator 14a Bracket 15 Slide plate 16 Home position 17 Bolt (for fixing main body) 18 Bolt (for swing mechanism) 19 Bolt 20 Steel pipe 21 Crank mechanism 22 Guide rod bracket 23 Guide rod 30 Bolt 50 Circumferential welding machine 52 Wedge-shaped backing member 52a Annular divided body 52b Annular divided body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroyuki Tamaki, inventor Hiroyuki Tamaki 1-20-1 Shimotani, Tsurumi-ku, Yokohama, Kanagawa Prefecture, Japan Steel Pipe Construction Shimotani Dormitory A309 (72) Inventor, Kazuyuki Saito Kawagoe, Saitama 2-8-65 Yoshinodai Denyo Co., Ltd. Saitama Plant

Claims (7)

[Claims] 1. An internal clamp device for circumferentially welding a steel pipe whose ends are beveled to each other from the inside of the pipe, wherein a plurality of curved backing members are provided on the circumference of the internal clamp device. Reciprocatingly arranged on the head of the plunger, expanding means for correcting the inner diameter of the steel pipe, and when the backing member of the expanding means contacts the inner wall of the steel pipe,
A gap filling means for filling a gap formed between the end portions of adjacent backing members with a gap filling means for making the backing member continuous by inserting a backing member. Internal clamp device equipped. 2. The expanding means fits the backing member via a backing metal holder mounted on the heads of a plurality of reciprocating plungers. Internal clamp device equipped with the void filling means. 3. The backing member has a curved shape whose outer peripheral shape divides the inner peripheral shape of a steel pipe into equal parts, and is formed with a predetermined angle at both ends thereof, and the vicinity of the central portion of the backing member is the same. It is screwed and fixed to the stopper holder of the plunger, and it is slidable in the concave groove of the stopper holder that is formed in the concave shape of the plunger head located on the left and right of the plunger that is screwed and fixed. An internal clamp device comprising the gap filling means according to claim 1 or 2, which is loosely fitted. 4. The gap filling means forms a V-shaped gap formed between the backing member and the backing member adjacent to the backing member when the backing member contacts the inner wall surface of the steel pipe. Insertion and compensation of the compensation backing metal of the compensation backing member is performed by simultaneous operation of the first actuator that allows sliding in the wall surface direction and the second actuator that allows sliding in the pipe length direction of the steel pipe. An internal clamp device comprising the gap filling means according to claim 1. 5. A swinging mechanism that pivotally supports a second actuator of the gap filling means on the head of the first actuator, and a second actuator that is rotatable by the swinging mechanism. The rotation restricting mechanism for restricting the rotation of the guide includes a guide rod bracket which is screwed and fixed to the main body of the internal clamp device, and in which the guide rod is erected, and the edge of the guide rod which is engaged with the first actuator. The guide rod is inserted into the guide hole of the bracket so that the guide rod can freely fit, and the fitting play is restricted at both edges of the guide hole. Accordingly, the rotation of the swing mechanism is regulated, and the internal clamp device including the gap filling means according to claim 1 or 4. 6. The backing member sandwiches both side portions near both ends thereof with a plate-shaped guide pin for externally fitting a guide pin collar, and the guide pin of the protective member The backing member protection mechanism for restricting sliding of both end portions of the backing member by a backing metal holder which is a through hole and forms a long guide groove. Internal clamp device equipped with void filling means. 7. The backing member has a long shaft bolt projectingly screwed and fixed to a bottom surface near both ends thereof, and the projecting long shaft bolt is formed into a concave groove of the backing plate holder. 2. The gap filling means according to claim 1, further comprising a backing member protection mechanism for penetrating the formed long hole to regulate sliding of the backing holder in the concave groove. Internal clamp device.