Apparatus and method for welding joint fixtures to a pipe

• US 5,075,527 A
• Filed: 06/27/1990
• Issued: 12/24/1991
• Est. Priority Date: 07/01/1989
• Status: Expired due to Term

• Current Assignee: Xepro Tubing Company Limited
• Original Assignee: Xepro Tubing Company Limited
• Inventors: Ikuma, Takeji
• Primary Examiner(s): Shaw, Clifford C.
• Application Number:
  US07/544,662
• Time in Patent Office: 545 Days
• Field of Search: 219/159, 219/125.11, 219/60 R, 219/61, 228/44.5, 228/49.2, 228/49.3, 228/59.1
• US Class Current: 219/59.1
• CPC Class Codes: B23K 37/053 aligning cylindrical work; Clamping devices therefor

Abstract

An apparatus and a method for welding joint fixtures to either end of a pipe at a given angles of attachment. A retaining mechanism on both the driver side and the follower side for joint fixtures is provided on either end of a horizontally elongated table on which a pipe is to be horizontally placed. The joint fixtures are secured on the opposing inner ends of the retaining mechanisms via clamping devices to receive the pipe therebetween. The retaining mechanism for the joint fixture on the driver side includes a device for establishing the angle of attachment of the joint fixture so that the joint fixture can be turned to a predetermined angular position. After the angle of attachment of the joint fixture to the pipe is determined, the junctions between the joint fixtures and the pipe on either end are held in place by gripping devices for tentative welding using welding torches. When the tentative welding is completed, the gripping devices are released and the entire circumference of respective junctions is welded by the welding torches.

Claims

1. An apparatus for welding joint fixtures to the ends of a narrow pipe, said apparatus comprising:

a table horizontally elongated along the length of the pipe and which supports the pipe at both ends thereof, said table having a driver side at one end of the pipe and a follower side at the opposite end of the pipe;

retaining mechanisms for joint fixtures disposed at the opposite sides of said table, one retaining mechanism being on the driver side of the table and the other on the follower side of the table, each retaining mechanism having a rotary shaft that is coaxially aligned with the pipe and that has an end opposing the end of the other rotary shaft and on which are mounted clamp means for holding a joint fixture, said retaining mechanism for a joint fixture on the driver side being fixed on the table and having a means for turning the joint fixture for a predetermined angle so that the joint fixture will be arranged at a given angle of attachment to the pipe, and said retaining mechanism for the joint fixture on the follower side of the table being movable in the longitudinal direction of the table;

a pair of grip means disposed adjacent the clamp means of the retaining mechanism on both the driver and the follower side to hold the joint fixtures and the pipe suspended therebetween securely in place in a concentric manner;

a pair of welding torches disposed both on the driver side and follower side of said table in a vertical arrangement and normal to said grip means, each pair of welding torches being operative to weld a joint fixture to one end of the pipe; and

means for rotating one of the retainer mechanisms to rotate the fixtures and pipe during welding.

2. The apparatus for welding joint fixtures to a pipe as claimed in claim 1, wherein retaining mechanisms for joint fixtures on the driver side and on the follower side are each provided with means for storing the rotary shaft of the retaining mechanism to its initial position after welding is completed so that a joint fixture to be welded in the subsequent cycle can be retained at the given angle required for its attachment.

3. The apparatus for welding joint fixtures to a pipe as claimed in claim 2, wherein said means for restoring the rotary shaft of the retaining mechanism on the driver side to its initial position includes:

a projection for indicating the original angular position which is provided on a pulley at one end of the rotary shaft; and

a sensor for detecting the initial position, indicated by the projection, which is connected to a pulse motor, said pulse motor actuating the rotary shaft in response to said sensor.

4. The apparatus for welding joint fixtures to a pipe as claimed in claim 2, wherein said position restoring mechanism on the follower side comprises a pinion provided at one end of the rotary shaft, and a rack which is actuated by means of a cylinder which in turn is disposed normal to the rotary shaft supported on a platform.

5. The apparatus for welding joint fixtures to a pipe as claimed in claim 1, wherein said clamp means for securing the joint fixtures on the driver and the follower sides each include a conical cam which is provided on one end of the rotary shaft and is movable in the axial direction, a cylinder which causes the conical cam to move along the rotary shaft via a U-shape lever, a flange which is provided at the tip end of said rotary shaft, a fixed claw projecting horizontally from the flange on its outer side, and a movable claw journalled to the outer periphery of said flange in a freely swinging manner.

6. The apparatus for welding joint fixtures to a pipe as claimed in claim 1, wherein said grip means for holding the pipe and the joint fixtures at their junctions in place comprises a pair of grips with a V-shape notch each at the tip that are laterally arranged on both sides of the junction, and a cylinder which presses the grips simultaneously against the junction from both sides.

7. The apparatus for welding joint fixtures to a pipe as claimed in claim 1, wherein said pair of welding torches for welding the junctions between the pipe and the joint fixtures are the pair of welding torches that are vertically arranged so as to point the nozzles from the top and the bottom of the junction.