GB2175833A - Welding jig - Google Patents

Abstract

In welding a hollow aerofoil shaped vane 10 to an end piece 12 using a gas-shielded arc-welding technique it is usually necessary to supply inert gas into the hollow vane. If there is any dimensional mismatch between the two items then the inert gas will escape thereby reducing the quality of weld. A jig is provided which is attached to the end piece during welding. The jig comprises a plate 18 with holding tangs and a deformable sealing portion 24 which abuts against part of the joint between the two items thereby at least partially preventing gas leakage. <IMAGE>

Description

SPECIFICATION Welding jig This invention relates to a jig for use in gasshielded arc-welding.

When welding together two hollow items such as an aerofoil shaped vane to an end blanking piece using a gas-shielded arc-welding technique it is usually necessary to supply inert gas into the hollow of the vane. This supply of gas to the backface of the welding area is necessary for a high quality weld. Prior to welding there may be some dimensional mismatch between the two items, especially if there are both fabricated from sheet metal. If there is too much leakage of inert gas from any gaps between the two items then the quality of welding may suffer. Therefore a problem exists in preventing too much gas from escaping during the welding process.

The object of the present invention is to provide a jig which overcomes the problem described above.

The main advantage of such a jig is that by preventing too much gas from escaping a good quality weld results.

The invention will now be described by way of an example with reference to the accompanying drawings in which: Figure 1 depicts an exploded diagram of an aerofoil shaped vane prior to welding to an end blanking piece; Figure 2 depicts a view of a jig constructed in accordance with the present invention; Figure 3 shows a view of the jig in the direction of arrow A in Fig. 2; Figure 4 depicts the jig as shown in Fig. 2 with the end blanking piece inserted therein; Figure 5 depicts a view of the jig and end blanking piece in the direction of arrow B of Fig. 4; Figure 6 depicts the welding together of the vane and end blanking piece.

Referring to Fig. 1, the vane 10 is formed into a hollow aerofoil and the end piece 12 is of similar section to the vane 10 at the joint to be welded, although there is a degree of mismatch. A supply of argon introduced into the vane 10 by way of a pipe 14 constrained within a rubber bung 16. Prior to welding, the bung 16 is partially inserted into the vane 10 so that there is a gas-tight seal between the vane 10 and bung 16.

Referring to Figs. 2 and 3, the jig 18 comprises a flat base member 20, holding tangs 22, and a sealing portion 24. The sealing portion 24 itself comprises a deformable, resilient portion 26 and a protective surface 28, which can be a plastic film stuck to the resilient portion.

Referring now to Figs. 4, 5 and 6, prior to welding, the end piece 12 is inserted into the jig 18 by sliding it in the direction of arrow A.

The end piece 12 is held in the jig 18 by the holding tangs 22. The sealing portion 24 is partially deformed by the end piece 12, and further deformed when the vane 10 is held against the end piece 12 during the welding operation. As can be seen in Fig. 6, during welding, the sealing portion abuts against part of the joint 30 between the vane 10 and end piece 12 thus preventing the escape of gas from that part of the joint.

After one side of the joint has been tackwelded it is possible to take the jig off the end piece and slide it back on so that the tack-welded side now abuts against the sealing portion.

1. A jig comprising a deformable sealing portion and one or more holding members.

2. A jig as claimed in claim 1 for use in welding together two items, at least one of which is hollow and has inert gas introduced therein during welding together of opposing joint faces of the two items, the jig comprising; a deformable sealing portion which, in use, abuts against the two items along at least part of the joint thereof to at least reduce gas escaping therefrom; and one or more holding members which, in use, hold the jig to one of the items.

3. A jig as claimed in claims 1 or claim 2 wherein the jig further comprises a main body which is a substantially flat plate, and the sealing portion and holding members are attached to the plate.

4. A jig as claimed in any one of the preceding claims wherein the sealing portion and the holding members are arranged substantially facing one another thereby allowing the item which is to be held by the jig, to be slid between them.

5. A jig as claimed in any one of the preceding claims wherein the holding members are tangs arranged to engage a flange portion on an item to be held.

6. A method of welding together two items at least one of which is hollow comprising the steps of: inserting one of the items into a jig as claimed in any one of claims 1 to 5; introducing a flow of inert gas into the hollow portion of said one or more items; welding together the two items along the joint thereof at a location remote from the sealing portion of the jig.

7. The method of claim 6 further comprising the step of removing the jig and reinserting the item in a different orientation to allow the welding of the portion of the joint previously covered by the sealing portion.

8. A jig substantially as described herein with reference to any of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Welding jig This invention relates to a jig for use in gasshielded arc-welding. When welding together two hollow items such as an aerofoil shaped vane to an end blanking piece using a gas-shielded arc-welding technique it is usually necessary to supply inert gas into the hollow of the vane. This supply of gas to the backface of the welding area is necessary for a high quality weld. Prior to welding there may be some dimensional mismatch between the two items, especially if there are both fabricated from sheet metal. If there is too much leakage of inert gas from any gaps between the two items then the quality of welding may suffer. Therefore a problem exists in preventing too much gas from escaping during the welding process. The object of the present invention is to provide a jig which overcomes the problem described above. The main advantage of such a jig is that by preventing too much gas from escaping a good quality weld results. The invention will now be described by way of an example with reference to the accompanying drawings in which: Figure 1 depicts an exploded diagram of an aerofoil shaped vane prior to welding to an end blanking piece; Figure 2 depicts a view of a jig constructed in accordance with the present invention; Figure 3 shows a view of the jig in the direction of arrow A in Fig. 2; Figure 4 depicts the jig as shown in Fig. 2 with the end blanking piece inserted therein; Figure 5 depicts a view of the jig and end blanking piece in the direction of arrow B of Fig. 4; Figure 6 depicts the welding together of the vane and end blanking piece. Referring to Fig. 1, the vane 10 is formed into a hollow aerofoil and the end piece 12 is of similar section to the vane 10 at the joint to be welded, although there is a degree of mismatch. A supply of argon introduced into the vane 10 by way of a pipe 14 constrained within a rubber bung 16. Prior to welding, the bung 16 is partially inserted into the vane 10 so that there is a gas-tight seal between the vane 10 and bung 16. Referring to Figs. 2 and 3, the jig 18 comprises a flat base member 20, holding tangs 22, and a sealing portion 24. The sealing portion 24 itself comprises a deformable, resilient portion 26 and a protective surface 28, which can be a plastic film stuck to the resilient portion. Referring now to Figs. 4, 5 and 6, prior to welding, the end piece 12 is inserted into the jig 18 by sliding it in the direction of arrow A. The end piece 12 is held in the jig 18 by the holding tangs 22. The sealing portion 24 is partially deformed by the end piece 12, and further deformed when the vane 10 is held against the end piece 12 during the welding operation. As can be seen in Fig. 6, during welding, the sealing portion abuts against part of the joint 30 between the vane 10 and end piece 12 thus preventing the escape of gas from that part of the joint. After one side of the joint has been tackwelded it is possible to take the jig off the end piece and slide it back on so that the tack-welded side now abuts against the sealing portion. CLAIMS

1. A jig comprising a deformable sealing portion and one or more holding members.

2. A jig as claimed in claim 1 for use in welding together two items, at least one of which is hollow and has inert gas introduced therein during welding together of opposing joint faces of the two items, the jig comprising; a deformable sealing portion which, in use, abuts against the two items along at least part of the joint thereof to at least reduce gas escaping therefrom; and one or more holding members which, in use, hold the jig to one of the items.

3. A jig as claimed in claims 1 or claim 2 wherein the jig further comprises a main body which is a substantially flat plate, and the sealing portion and holding members are attached to the plate.

4. A jig as claimed in any one of the preceding claims wherein the sealing portion and the holding members are arranged substantially facing one another thereby allowing the item which is to be held by the jig, to be slid between them.

5. A jig as claimed in any one of the preceding claims wherein the holding members are tangs arranged to engage a flange portion on an item to be held.

6. A method of welding together two items at least one of which is hollow comprising the steps of: inserting one of the items into a jig as claimed in any one of claims 1 to 5; introducing a flow of inert gas into the hollow portion of said one or more items; welding together the two items along the joint thereof at a location remote from the sealing portion of the jig.

7. The method of claim 6 further comprising the step of removing the jig and reinserting the item in a different orientation to allow the welding of the portion of the joint previously covered by the sealing portion.

8. A jig substantially as described herein with reference to any of the accompanying drawings.