JPS637426Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a torch for welding the inner surface of a tube, and particularly to a torch for welding the inner surface of a tube for a welding machine that performs circumferential welding between a tube and a tube plate from the inside of the tube by the Teig welding method.

FIG. 1 is an external view of a conventional tube inner surface welding head, and FIG. 2 is a vertical cross-sectional view of a tube inner surface welding torch section incorporated in the welding head. In Figures 1 and 2, the tube plate 10 and the pipe 12, which are the objects to be welded, have a joint 1.
Welded in step 4. A torch 18, which is rotationally driven by a welding head 16, is supported concentrically within a hole 22 provided in the tube sheet 10 via a centering tool 20 fitted on the outside of the torch 18, and a nozzle 24 is provided on the outer periphery of the tip of the torch. are fitted. The electrode rod 26 is the nozzle 2
4 from the hole 28 provided in the torch 18 to the side hole 30 of the torch 18
A set screw 3 is inserted into the side hole and is screwed into a screw hole 32 formed from the tip of the torch so as to reach this side hole.
It is pressed and fixed at 4. In addition, the screw hole 32
After screwing in the set screw 34, a stepped screw 36 is screwed in and the stepped portion 36a presses the inner protrusion 24a of the nozzle 24 to attach the nozzle to the torch 18.

Next, the operation will be explained. An arc is generated from the tip of an electrode rod 26 attached to the torch 18, and the tube sheet 10 and the tube 12 are melted at the joint 14 and rotated to weld. Weld joints 14 are generally provided at several hundred to several thousand locations on a tube sheet. When welding the joint portions 14 one after another, the electrode rod 26 must be replaced with a new electrode rod after welding at several to several tens of locations due to damage caused by high heat, oxidation, etc.

However, in the conventional torch 18 for welding the inner surface of a tube, when attaching or detaching the electrode rod 26, first remove the stepped screw 36 that fixes the nozzle 24, and then remove the set screw 34.
There was a drawback that it was necessary to loosen the electrode rod 26, and replacing the electrode rod 26 was time-consuming and troublesome.

The present invention was developed in view of the conventional problems mentioned above, and its purpose is to provide a torch for welding the inner surface of a tube that allows the metal fittings that fix the electrode rod to be directly operated from the outside, making it possible to easily attach and detach the electrode rod. It is about providing.

In order to achieve the above object, the present invention includes a nozzle that fits on the outer periphery of a welding torch, a nozzle fixing screw that fixes the nozzle by pressing it against the welding torch in the axial direction, and a center of the nozzle fixing screw. an electrode rod set screw that screws into and penetrates a screw hole provided in the part to fix the electrode rod to the welding torch;
It is characterized by having the following.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings. FIG. 3 is a longitudinal cross-sectional view showing one embodiment of the torch for welding the inner surface of a tube according to the present invention, in which the same parts as in FIG. 2 are given the same reference numerals. In FIG. 3, a through hole 38 is provided in the center of the stepped screw 36, and a hole 40 communicating with this through hole and reaching the horizontal hole 30 is formed in the torch 18, and is formed at the rear end side of the through hole 38. The electrode rod 26 is pressed and supported by the tip of a set screw 42 which is screwed into the threaded portion 38a and inserted into the through hole 38 and the hole 40.

The embodiment of the present invention has the above configuration,
When removing the electrode rod 26 from the torch 18, loosen the set screw 42 directly from the outside using a screwdriver or the like (not shown). Furthermore, when fixing the electrode rod 26, the set screw 42 may be directly tightened. On the other hand, when replacing the nozzle 24, the electrode rod 26 can be loosened at the same time by loosening the stepped screw 36, so the electrode rod 26 can be taken out first and then the nozzle 24 can be removed.

As described above, according to the present invention, since the set screw that fixes the electrode rod can be operated directly from the outside, the electrode rod can be easily attached and removed, and the electrode rod can also be removed at the same time as tightening the stepped screw that fixes the nozzle. This has the effect of making it easier to replace the nozzle.

[Brief explanation of the drawing]

Fig. 1 is an external view of a conventional pipe inner welding head, Fig. 2 is a vertical cross-sectional view of a conventional pipe inner welding torch incorporated into the welding head, and Fig. 3 is an implementation of the present pipe inner welding torch. It is a longitudinal cross-sectional view showing an example. In each figure, the same members are given the same symbols, 10 is a tube plate, 12 is a pipe, 14 is a joint, 16 is a welding head,
18 is a torch, 20 is a centering tool, 22 is a hole, 24 is a nozzle, 26 is an electrode rod, 28 is a hole, 30 is a horizontal hole,
32 is a screw hole, 34 is a set screw, 36 is a stepped screw, 38 is a through hole, 40 is a hole, and 42 is a set screw.

Claims (1)

[Scope of utility model registration request] A nozzle that fits on the outer periphery of the welding torch, a nozzle fixing screw that fixes the nozzle by pressing it against the welding torch in its axial direction, and a screw hole that is screwed into the center of the nozzle fixing screw. A torch for welding an inner surface of a tube, comprising: an electrode rod fixing screw that penetrates the electrode rod and fixes the electrode rod to the welding torch.