JP2012076087A - Fixture for welding operation, welding method, and supporting skirt manufacturing method using them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for supporting members being welded while preventing them from moving relative to each other and from being damaged.SOLUTION: Each of the fixtures for welding operation (10A, 10B) used for holding skirt members 6 constituting a support skirt 4 by pulling the skirt members 6 toward each other by respective pulling mechanisms includes: a hook hole 11 for attaching the pulling mechanism; and a cutout 12 to which an angle 7 attached to the skirt member 6 is fitted. The cutout 12 has a shape corresponding to the angle 7, and is in surface or line contact with the angle 7.

Description

  The present invention relates to a welding work jig, a welding method, and a support skirt manufacturing method using them, and more particularly, to a method for holding a member to be welded.

  A large metal structure may be constructed by welding a plurality of members. For example, in the case of an LNG ship carrying LNG (liquefied natural gas), a cylindrical support skirt is welded to a spherical tank, and the support skirt is welded to a foundation deck of the LNG ship. The support skirt includes a plurality of skirt members arranged in the circumferential direction, and adjacent skirt members are welded to form a cylindrical support skirt.

  When welding members, it is necessary to support the members to be welded so that they do not move relative to each other. One way to support the members to be welded is to pull the members together by a pulling mechanism with the members butted. For example, the members to be welded can be supported by holding each member to be welded by the clamp and pulling the clamp to each other by the lever block. Japanese Patent Laid-Open Nos. 60-190789 and 61-51481 disclose a structure of a clamp used for pulling a member.

  In particular, when a strong pulling force is applied, it is necessary to increase the gripping force with which the clamp sandwiches the member. On the other hand, when the gripping force is increased, the member sandwiched between the clamps is scratched. There is a case. If the member sandwiched between the clamps is scratched, it may be necessary to rework (for example, welding the scratched portion), which is not preferable because it increases the working time.

JP-A-60-190789 JP 61-51481 A

  Therefore, an object of the present invention is to provide a technique for supporting the members to be welded so as not to move relative to each other and to damage the members.

  In one aspect of the present invention, there is provided a welding work jig for holding welded members by pulling welded members to be welded together by a pulling mechanism. The welding work jig includes an attachment structure for attaching a pulling mechanism and a notch that is fitted into a fitting portion of the welding member. The notch has a shape corresponding to the fitting portion, and contacts the welding member by surface contact or line contact.

  The welding work jig preferably has a temporary fixing structure for temporarily fixing the welding work jig to the fitting portion of the welding member. In one embodiment, the temporary fixing structure includes a contact member for contacting the fitting portion, and a holding member for holding the contact member. The contact member is formed with a male screw, and the holding member is formed with a female screw that is screwed to the male screw. When the contact member is rotated in a specific direction, the contact member is brought into contact with the fitting portion. .

  In one embodiment, the notch has an abutment surface that abuts a surface that faces the notch of the fitting portion.

  In another aspect of the present invention, the above-described welding work jig is used in a welding method. The welding method includes a step of attaching a welding work jig to the fitting portion of the welding member, a step of attaching a pulling mechanism to the welding work jig, and a welding mechanism by pulling the welding work jigs using a pulling mechanism. A step of holding the member, and a step of welding the welding member in a state where the welding member is held.

  When the welding work jig is provided with a temporary fixing structure, the welding work jig is temporarily fixed to the fitting portion using the temporary fixing structure in the process of attaching the welding work jig to the fitting portion of the welding member. It is preferred that

  In one embodiment, the fitting portion includes a root portion joined to the main body portion of the welding member, and a reinforcing portion attached to the tip of the root portion and extending in a direction different from the root portion. In this case, it is preferable that a reinforcing part is not provided in a part of the root part, and the welding work jig is fitted from a part of the root part of the fitting part.

  In another aspect of the present invention, a manufacturing method is provided for manufacturing a support skirt for a spherical tank that accumulates LNG. The manufacturing method includes a step of attaching a welding work jig provided with an attachment structure for attaching a pulling mechanism to a plurality of skirt members to which a reinforcing member is attached, and a notch into which the reinforcing part is fitted, and a welding work jig. The step of attaching the pulling mechanism, the step of holding the adjacent skirt member by pulling the welding work jigs together using the pulling mechanism, and the step of holding the adjacent skirt member while holding the adjacent skirt member And a process of welding.

  According to the present invention, there is provided a technique for holding members to be welded so as not to move relative to each other and supporting the members without damage.

It is a side view which shows an example of the structure of the LNG ship in one Embodiment of this invention. It is sectional drawing which shows the structure of the hold in one Embodiment of this invention. It is a side view which shows the structure of the support skirt in one Embodiment of this invention. It is sectional drawing which shows the structure of the support skirt in one Embodiment of this invention. It is a figure which shows the structure of the lower end part of the angle in one Embodiment of this invention. It is a conceptual diagram which shows the welding method in one Embodiment of this invention. It is a top view which shows the structure of the jig | tool for welding operation in one Embodiment of this invention. It is a top view which shows the structure of the jig | tool for welding operation in other embodiment of this invention. It is a top view which shows the structure of the jig | tool for welding operation in other embodiment of this invention.

  In one embodiment of the present invention, the welding jig and welding method of the present invention are applied to the welding of a support skirt that supports a spherical tank of an LNG ship. Below, the structure of an LNG ship, a spherical tank, and a support skirt is demonstrated first.

  FIG. 1 is a side view showing an example of the structure of an LNG ship. The hull 2 of the LNG ship 1 is provided with a hold, and a plurality of spherical tanks 3 are accommodated in the hold. The spherical tank 3 is a tank for accumulating LNG (liquefied natural gas). The upper part of the spherical tank 3 is covered with a tank cover 2a.

  FIG. 2 is a cross-sectional view showing the structure of the hold provided in the hull 2. The upper end of the cylindrical support skirt 4 is welded to the equator of the spherical tank 3, and the lower end of the support skirt 4 is welded to the foundation deck 5.

  3 to 5 are views showing the structure of the support skirt 4. Specifically, FIG. 3 is a side view of the support skirt 4, FIG. 4 is a cross-sectional view of the support skirt 4 cut along a horizontal plane, and FIG. 5 is a cross-section when the support skirt 4 is cut along a vertical plane. FIG. With reference to FIG. 3, the support skirt 4 includes a plurality of skirt members 6 arranged in the circumferential direction. Adjacent skirt members 6 are joined by welding. As shown in FIG. 4, an angle 7 is welded to the outer peripheral surface of each skirt member 6 as a reinforcing member. In the present embodiment, the angle 7 has an L-shaped cross section and includes a root portion 21 and a reinforcing portion 22. The root portion 21 is a portion extending in the radial direction of the support skirt 4 and is welded to the skirt member 6. The reinforcing portion 22 is joined to the tip of the root portion 21 and is a portion extending in a direction different from the root portion 21, specifically, in a substantially circumferential direction of the support skirt 4. Since the angle 7 is composed of the root portion 21 and the reinforcing portion 22, the strength of the angle 7 is increased.

  FIG. 5 is a view showing the structure of the lower end portion of the support skirt 4. In the present embodiment, the lower end of the skirt member 6 of the support skirt 4 is welded to the foundation deck 5 as described above. In the vicinity of the lower end of the skirt member 6, the root portion 21 of the angle 7 is cut obliquely. The reinforcement part 22 is not provided about the part cut | disconnected diagonally. As will be described later, such a structure facilitates attaching the welding work jig to the angle 7 in the welding method of the present embodiment.

  Referring to FIG. 6, in the welding method of the present embodiment, skirt members 6 adjacent in the circumferential direction are welded by butt welding. Here, in order to weld the skirt member 6, the skirt members 6 to be welded must be held in contact with each other. Below, the method to hold | maintain the skirt member 6 welded in this embodiment is demonstrated. In the following description, one of the skirt members 6 to be welded is denoted by reference numeral 6A and the other is denoted by reference numeral 6B. Of the angles 7 joined to the skirt member 6A, the one closest to the skirt member 6B is the angle. 7A, and the angle 7 that is closest to the skirt member 6A among the angles 7 joined to the skirt member 6B is referred to as an angle 7B.

  In the present embodiment, the lever block 8 and the welding work jigs 10A and 10B are used to hold the skirt members 6A and 6B. The lever block 8 is a pulling mechanism including a lever main body 8a, hooks 8b and 8c, and wires 8d and 8e. A hook 8b is coupled to the end of the wire 8d, and a hook 8c is coupled to the end of the wire 8e.

  The welding work jigs 10 </ b> A and 10 </ b> B are jigs used for attaching the angles 7 </ b> A and 7 </ b> B to the lever block 8. One welding work jig 10A is attached to the angle 7A of the skirt member 6A, and the welding work jig 10B is attached to the angle 7B of the skirt member 6B.

  FIG. 7 is a plan view showing the structure of the welding jigs 10A and 10B. The welding work jigs 10 </ b> A and 10 </ b> B are plate-like members each having a hook hole 11 (attachment structure) and a notch 12. The hook hole 11 is a structure for attaching the hooks 8 b and 8 c of the lever block 8, and the welding jigs 10 A and 10 B are attached to the lever block 8 by hooking the hooks 8 b and 8 c to the hook hole 11. It is done. The notch 12 has a structure for attaching the welding jigs 10A and 10B to the angles 7A and 7B. By fitting the notches 12 of the welding work jigs 10A and 10B into the angles 7A and 7B, the welding work jigs 10A and 10B are attached to the angles 7A and 7B. When the lever body 8a is operated with the hooks 8b and 8c attached to the welding jigs 10A and 10B, the hooks 8b and 8c, that is, the welding jigs 10A and 10B are pulled together. Accordingly, the skirt members 6A and 6B are held in contact with each other.

  Next, the welding procedure of this embodiment will be described in detail with reference to FIG. First, the notches 12 of the welding jigs 10A and 10B are fitted into the angles 7A and 7B, respectively. At first glance, FIG. 6 shows that the presence of the reinforcing portions 22 of the angles 7A and 7B (that is, the portions extending in the circumferential direction from the end of the root portion 21) causes the welding jigs 10A and 10B to be angled 7A. , May seem to interfere with attachment to 7B. However, as shown in FIG. 5, the reinforcing portions 22 are not provided at the lower ends of the angles 7A and 7B. Therefore, the welding work jigs 10A and 10B are connected to the lower ends of the angles 7A and 7B. The notch 12 can be fitted.

  Returning to FIG. 6, with the welding jigs 10A and 10B attached to the angles 7A and 7B, the hooks 8b and 8c of the lever block 8 are hooked into the hook holes 11 of the welding jigs 10A and 10B. Further, the lever block 8 is operated to apply a tensile force between the welding work jigs 10A and 10B. Thereby, the skirt members 6A and 6B are held in contact with each other. The skirt members 6A and 6B are welded by butt welding in a state where the skirt members 6A and 6B are in contact with each other.

  When a tensile force is applied between the welding jigs 10A and 10B by the lever block 8, the welding jigs 10A and 10B and the angles 7A and 7B are in contact with each other by surface contact or line contact. is important. Specifically, when a tensile force is applied between the welding work jigs 10A and 10B, the surface 21a of the root portion 21 of the angle 7A that faces the angle 7B becomes the surface 12b (contact surface) of the notch 12. Surface contact or line contact is made, and the surface 21b of the root portion 21 of the angle 7B that faces the angle 7A makes surface contact or line contact with the surface 12a (contact surface) of the notch 12. Since the skirt members 6A and 6B are members having a considerably large weight, it is necessary to apply a large pulling force by the lever block 8, and this may cause the angles 7A and 7B to be damaged. However, in this embodiment, since the welding jigs 10A and 10B and the angles 7A and 7B are in contact with each other by surface contact or line contact, local force is prevented from acting on the angles 7A and 7B. The damage of the angles 7A and 7B can be suppressed.

  As described above, in this embodiment, the notch 12 of the welding work jigs 10A and 10B has a shape corresponding to the angles 7A and 7B, and the angles 7A and 7B and the welding work jig 10A and 10B are contacted by surface contact or line contact. As a result, damage to the angles 7A and 7B when the welding jigs 10A and 10B are pulled by the pulling mechanism (lever block 8) is suppressed.

  In order to facilitate the work of attaching the welding work jigs 10A and 10B to the angles 7A and 7B and further attaching the lever block 8 to the welding work jigs 10A and 10B, the welding work jigs 10A and 10B are provided. It is preferable that temporary fixing structures that are temporarily fixed to the angles 7A and 7B are provided in the welding jigs 10A and 10B. FIG. 8 is a plan view showing an example of such a temporary fixing structure. The welding work jigs 10 </ b> A and 10 </ b> B include a nut 13 and a bolt 14. The nut 13 has a female thread, and the bolt 14 has a male thread. In such a temporary fixing structure, the nut 13 functions as a holding member that holds the bolt 14, and the bolt 14 functions as an abutting member that abuts on the angles 7A and 7B. Specifically, when the bolt 14 is rotated in a specific direction (typically clockwise) with the welding jigs 10A and 10B fitted in the angles 7A and 7B, the bolt 14 is turned to the angles 7A and 7B. Abutted. Accordingly, the welding work jigs 10A and 10B are temporarily fixed to the angles 7A and 7B. Since it is sufficient if the welding jigs 10A and 10B are held, the force with which the bolt 14 is brought into contact with the angles 7A and 7B may be weak. If the welding jigs 10A and 10B are temporarily fixed to the angles 7A and 7B, the hooks 8b and 8c of the lever block 8 are hooked into the hook holes 11 of the welding jigs 10A and 10B. The operation of operating and applying a tensile force between the welding work jigs 10A and 10B is facilitated. Conventionally, a work by a plurality of people is required, but a work by one person is also possible. Further, as the temporary fixing structure, for example, an electromagnetic chuck or a structure that applies pressure with a spring may be used.

  In order to further suppress damage to the angles 7A and 7B, it is preferable that at least a surface (contact surface) that is in contact with the angles 7A and 7B among the surfaces of the notch 12 is covered with the resin layer 15. . FIG. 9 is a plan view showing an example of welding work jigs 10A and 10B having such a configuration. 9, the entire surface of the notch 12 is covered with the resin layer 15. Thereby, damage of angle 7A, 7B can be suppressed further. The temporary fixing structure described above may also be attached to the welding work jigs 10A and 10B in FIG.

  Although various embodiments of the present invention have been specifically described above, the present invention should not be construed as being limited to the above-described embodiments. In particular, it should be noted that the present invention is generally applicable when holding welded members by pulling the welded members to be welded together by a pulling mechanism. The welding member can be welded by the same method by fitting the welding work jig into a part (fitting part) of the welded member to be welded and pulling the welding work jig by a pulling mechanism (for example, a lever block).

  In the above-described embodiment, the L-shaped angle 7 is used as the reinforcing member of the support skirt 4, but reinforcing members having other shapes may be used. For example, a T-shaped reinforcing member can be used instead of the angle 7. In this case, the root portion 21 and the reinforcing portion 22 are joined near the center of the reinforcing portion 22. When a reinforcing member having another shape is used, a notch 12 corresponding to the shape is provided in the welding jigs 10A and 10B.

1: LNG ship 2: Hull 3: Spherical tank 4: Support skirt 5: Foundation deck 6, 6A, 6B: Skirt member 7, 7A, 7B: Angle 8: Lever block 8a: Lever body 8b, 8c: Hook 8d, 8e : Wire 10A, 10B: Welding jig 11: Hook hole 12: Notch 12a, 12b: Surface 13: Nut 14: Bolt 15: Resin layer 21: Root portion 21a, 21b: Surface 22: Reinforced portion

Claims (9)

A welding work jig for holding the welding members by pulling the welding members to be welded together by a pulling mechanism,
An attachment structure for attaching the pulling mechanism;
A notch to be fitted into the fitting portion of the welding member,
The said notch has a shape corresponding to the said fitting part, and is a jig | tool for welding operation which contacts the said welding member by surface contact or line contact. The welding work jig according to claim 1,
A welding work jig having a temporary fixing structure for temporarily fixing the welding work jig to the fitting portion of the welding member. A welding tool according to claim 2,
The temporary fixing structure is
A contact member for contacting the fitting portion;
A holding member for holding the contact member,
The contact member is formed with a male screw, the holding member is formed with a female screw that is screwed with the male screw, and the contact member is fitted when the contact member is rotated in a specific direction. Welding jig that contacts the part. A welding work jig according to any one of claims 1 to 3,
The said notch has the contact surface contact | abutted with the surface facing the said notch of the said fitting part. A welding method using the jig for welding work according to claim 1. The welding method according to claim 5,
Attaching the welding work jig to the fitting portion of the welding member;
Attaching a pulling mechanism to the welding work jig;
Holding the welding member by pulling between the welding jigs using the pulling mechanism;
Welding the welding member in a state where the welding member is held. A welding method using the welding work jig according to claim 2 or 3,
Attaching the welding work jig to the fitting portion of the welding member;
Attaching a pulling mechanism to the welding work jig;
A step of holding the welding member by pulling the welding work jigs together using the pulling mechanism;
Welding the welding member in a state where the welding member is held,
In the step of attaching the welding work jig to the fitting part of the welding member, the welding work jig is temporarily fixed to the fitting part using the temporary fixing structure. A welding method according to any one of claims 5 to 7,
The fitting portion is
A root portion joined to the main body portion of the welding member;
A reinforcing portion attached to the tip of the root portion and extending in a direction different from the root portion;
A part of the root portion is not provided with the reinforcing portion,
The welding jig is fitted from the part of the root portion of the fitting portion. A manufacturing method for manufacturing a support skirt for a spherical tank that accumulates LNG, comprising:
Attaching a welding work jig comprising an attachment structure for attaching a pulling mechanism to a plurality of skirt members to which reinforcement members are attached, and a notch into which the reinforcement part is fitted;
Attaching a pulling mechanism to the welding work jig;
Holding the adjacent skirt members by pulling the welding work jigs together using the pulling mechanism;
And welding the adjacent skirt members in a state where the adjacent skirt members are held.

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