JPS5832875Y2 - Internal clamping device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an inner surface clamping device as a fixing jig used for welding joints of pipes such as steel pipes.

In FIG. 1, a conventional example will be described.

On the peripheral wall of the housing 1, a plurality of plungers 2 arranged on the circumference and capable of protruding in the radial direction are provided symmetrically at two locations along the axis. A clamp pawl 4 is fixed by a bolt 3, and the upper surface of the pawl 4 is formed into a friction arc surface that comes into contact with the inner wall of the pipe W to be jointly welded.

Thus, the plungers 2 in each row are moved in the radial direction via the link plate 7 by the movement of the pistons 6 of the air cylinders 5 attached to both sides of the housing 10, so that the plungers 2 can expand in diameter. is formed.

When this clamp device is used for welding, it is inserted into the joint part A of the inner hole of the pipe W with the plunger 2 retracted (Fig. a), and then compressed air is supplied to one cylinder 5. is sent and the plunger claw 4 of one row is moved to the pipe W.
Then, the plunger claws 4 of the other row are similarly pressed against the inner wall of the other tube W, and after aligning the two tubes W in this way (Fig. b), welding is performed. It is designed to carry out the work.

By the way, when welding joints of pipes such as carbon steel pipes, which have the characteristic of obtaining good workability even when welded in contact with air, the above-mentioned clamping device is used to weld the joints. ~ Welding work can be carried out, but when welding steel pipes made of alloy steels other than carbon steel, such as stainless steel, chrome molybdenum steel, and titanium, if the welded part comes into contact with oxygen in the atmosphere, the material may change. Due to the characteristics that make it difficult to obtain good workability, it is necessary to shield the joint part A from the atmosphere during welding. Welding steel etc. is difficult.

For this reason, when conventionally welding joints of pipes made of alloy steel, etc., inert gas such as argon, nitrogen, helium, etc. is sealed inside the pipe W after the clamping device is inserted, or the clamping device is inserted after the clamping device is inserted. Bank shielding was performed by blocking both sides of the joint part A using a known method and then supplying inert gas into the interior of joint part A. Not only does this require a great deal of time and effort, but it also requires the entire inside of the pipe W to be filled with inert gas, which requires a large amount of shielding gas to be consumed, resulting in high costs.

Note that there is no particular problem with the method of shielding the welded portion on the outside of the joint A, since the tip of the torch can be locally easily shielded from the atmosphere by an airflow curtain.

The present invention has been made in order to eliminate the above-mentioned drawbacks. That is, the purpose of the present invention is to provide an inner surface clamping device that can bank shield only the joint portion without using any special human labor. It is in.

Hereinafter, the present invention will be explained based on an illustrated embodiment.

In the clamp device of the embodiment, as shown in FIGS. 2 to 4, there are stepped portions 1 at multiple locations (six locations in the illustration) on the peripheral wall of the closed cylinder 10 that rise in the K1 radial direction.
0a is formed, and cylinders 11 are integrally attached to the left and right end faces of the housing 10, respectively, and the end faces of each cylinder 11 are closed with flanges 12.

Therefore, plungers 1 are provided at two locations on the left and right sides of the stepped portion 10a.
3 passes through the shaft 14, and the plunger 13 is connected to the shaft 14 by the shaft 14 and a bolt 15 for fine length adjustment.
It is formed by a thick plate-shaped head 16 fixed to the upper end of the head.

This plunger 13 is connected to a piston 17 in the cylinder 11.
It is connected by pins 32 and 21 via a link plate 20 to a disc-shaped bushing 19 fixed to the tip of the shaft 18 of the cylinder 11, thereby supplying compressed air into the cylinder 11. Then, the plunger 13 is radially expanded by 5 Ktx.

Next, a collar-shaped ring 22 constituting a partition plate is fitted and fixed to the left and right ends of the outer periphery of the housing 10.
Further, on the outer end surface of each plunger head 16, two mounting bolts 23 are attached to a fan-shaped shutter 2 that matches the pipe diameter.
4 (see FIGS. 5 and 6), and each shutter 24 overlaps the outside of the ring 22.

This shutter 24, which constitutes a partition plate, includes a shielding plate 25 made of a heat-resistant elastic material such as a silicone rubber material with both ends cut diagonally, and a metallic material polymerized and bonded to a large part in the middle of the shielding plate 25. each shutter 24.
In the reduced diameter state (FIG. 2a) in which the plunger 13 is retracted, one shutter 24 rides on the outside of the other shutter 24, as shown in FIG. In the expanded diameter state in which the shunters 13 protrude (FIG. 2b), the shielding plates 2 of both shunters 24 are closed as shown in FIG. 7bK.
5 are closely continuous, so that the shutter 24 forms a partition plate together with the ring 22 and closes between the side periphery of the head 16 and the outer periphery of the housing 10.

Note that the outer circumferential surface between the stepped portions 10a of the housing 10 is
As shown in the figure, it is continuous with the circumferential surface of the cylinder 110.

In addition, a gas nozzle 27 is fixed at one location on the stepped portion 10a, and a gas supply pipe 28 connected to this nozzle 27 is drawn out to the outside.
Argon gas is supplied from the outside.

In addition, each bracket 29 at the diagonal lower part of the flange 12 has
A sliding roller 30 is pivotally supported, so that the entire device can slide on a receiving plate that is curved and recessed in cross section.

Next, the operation of the clamp device according to the embodiment configured as described above will be explained.

When this device is used for pipe joint welding, a fan-shaped shutter 24 is attached to the outer end surface of each plunger head 16 using a pole 23 according to the diameter of the pipe W to be welded, and is fixed to the outer end surface of each plunger head 16 as shown in FIG. After the plunger 13 is reduced in diameter as shown by aK, the joint A (Fig. 2b) of the pipe W to be welded is inserted, but since the device can slide on the bottom surface of the pipe W by the sliding row 230, , its insertion operation is easy.

Thereafter, dynamic pressure is vented to one cylinder 11 to force the flancia head 16 in one row to clamp the pipe WK on one side, and then in the same manner, the plunger head 16 in the other row is connected to the pipe WK on the other side. As shown in FIG. 2b1 and FIG. 7bK, the axes of both tubes W are reliably and precisely aligned, and inside the joint A, there are partition plates 22 on both sides. .24 and
...A small-volume annular closed space 31 is formed around the outer periphery of the clamp 10.

Therefore, by supplying argon to the supply pipe 28, the nozzle 27
If argon is released into the space 31 from the
The inside of the tank is bank shielded by argon gas.

Although gas escapes from a small gap in the joint A, since the argon supply pressure is kept slightly positive, there is no risk of outside air flowing into the space 31 (also, the amount of argon gas consumed It only takes a little bit.

Therefore, if the first layer welding work in the next process is carried out in this state, good workability can be obtained, and the above-mentioned bank shield requires almost no manpower, and the gas cost is low. nothing.

As described above, according to the inner surface clamping device according to the present invention, a small volume of dead space obtained by the diaphragm action of the shutter and the ring is formed inside the welded pipe joint part, and the same Since a nozzle is provided to fill the space with inert gas, there is no need to fill the entire pipe with inert gas as in the conventional case, and inert gas only needs to be supplied to the small volume of the closed space. The amount of gas required is small, and the time required to supply inert gas can be shortened.

Furthermore, the shutter is made of an elastic material, and a closed space is formed by the overlap of the shutters and the shutter and the ring. Gas is allowed to escape, and the closed space is inevitably replaced by inert gas, ensuring bank sealing even when welding is performed with the left and right pipes in close contact with each other.

Furthermore, even when welding pipes of various diameters, it is possible to maintain a closed space within the range where the shutters and rings overlap with each other, and when this range of overlap is exceeded, a removable fan-shaped shutter can be used. This can be dealt with very easily by replacing it with a longer one.

In addition, since there is no need to seal the entire entrance and exit of the pipe, there is no need for manpower or time for preparation, and therefore there is no reduction in the processing capacity of automatic welding (which improves the workability and labor-saving of joint welding). It has the effect of increasing

[Brief explanation of the drawing]

FIG. 1a is a sectional view of a conventional clamp device, FIG. 1A is an operational diagram of FIG. 1A, and FIG. Figure 2 is Figure 2 a.
Fig. 3 is a side sectional view taken along the line ■-■ in Fig. 2a, Fig. 4 is a cross-sectional view taken at a different cutting line from Fig. 2]. Fig. 5 is a sectional view of the clamp. The plan view, FIG. 6, is a sectional view taken along the line VI-VI in FIG. 5, and FIG.
FIG. 7 is an outer edge view of the shutter in the direction of arrow (2) in FIG. 3, and FIG. 7 is an operation diagram of FIG. 7a. A...Joint part, W...Pipe, 10...
... No clamp, 13 ... Plunger, 1
6...Plunger head, 22.24...
...Ring and shutter that constitute the partition plate, 27...
... Gas nozzle, 28 ... Supply pipe 631.
...Closed space.

Claims (1)

[Scope of utility model registration request] A plurality of plungers arranged on the circumference and extending in the radial direction are installed on the peripheral wall of a closed cylindrical housing that is formed to be inserted into and removed from the inner hole of a joint of a pipe such as a steel pipe. The two tubes are aligned by providing them symmetrically at two locations, and by moving the plunger to expand its diameter and compressing the left and right plunger heads against the inner peripheral surfaces of the left and right container tubes on both sides of the joint. In the inner surface clamping device that can be clamped together in a state, a fan-shaped shank made of a heat-resistant elastic material and shaped approximately along the inner wall of the tube is removably fixed to the outer end surface of each of the left and right plunger heads. Each of the shutters has a length such that the opposing ends of the adjacent shutters are overlapped at the position where the plunger is moved to reduce its diameter, and the length of the left and right housings is such that the opposing ends of the adjacent shutters are overlapped. 2
On the outer periphery of the joint part, a ring is protruded to overlap with the inner peripheral edge of each of the shutters, and a closed space is created inside the periphery of the joint by the left and right partition plates formed by the left and right shutters and the ring. What is claimed is: 1. A clamp device characterized in that a supply pipe for inert gas led from the outside is opened in the closed space.