Patent GB-1287172-A (GB)
Title: Movable welding jig and stringer-welding method
Inventor: OZAWA NAOSUKE
IPC: B23K9/02
Filed: 1970-09-17
Abstract: 1287172 Welding by fusion NIPPON KOKANKK 17 Sept 1970 44403/70 Heading B3R A movable welding jig for holding, in parallel vertical planes, elongated reinforcing ribs 14, 22 on a main plate 23 in a horizontal plane, particularly for ship manufacture, comprises a support 2 which is carried, by way of posts 3, by members 30 having wheels 5 engaging the main plate, and carries rollers 15, 16 acting to hold the ribs in vertical planes, and rollers 17 acting to press the ribs downwardly against the main plate, the whole jig being movable longitudinally of the ribs during said holding and pressing of the ribs. In addition to the wheels 5, providing for longitudinal movement of the jig, the members 30 carry wheels 6 for transverse adjusting movement of the jig. These wheels 6 may be pressed down on to the main plate, to support the jig by a double-acting fluid pressure jack 21. The wheels 5, 6 are respectively driven by motors 7, 8 through belt or chain transmissions, shafts 12, 13, bevel gears 11, shafts 9, 10 and further bevel gears, the shaft 10 being telescopic to allow for vertical movement of the wheels 6. The rollers 15, 16 are carried by arms 41 depending from the support 2. The rollers 15 have their axes fixed relative to their respective arms 4<SP>1</SP> while the rollers 16 are laterally movable, being mounted on their respective arms 4<SP>1</SP> by way of fluid pressure devices 20. The righthand roller 15<SP>1</SP> is carried by the right-hand member 30 or post 3 and is driven, by way of a transmission 38, by the shaft 9. The rollers 17 are carried by pistons of fluid pressure devices 19, cylinders of which are fixed to the support 2 or to an arm 4<SP>1</SP>. The rollers 17 may act on the top edges of flat ribs or, as shown, on the transverse members of T-ribs. The fluid pressure devices 19-21 may be energized by an oil pump 18. The arms 4<SP>1</SP> may be transversely adjusted as by movement and screw fixing in transverse slots in the support 2. The posts 3 may be similarly adjusted with respect to the support 2 to vary the post spacing, the bevel gears 11 being slidably splined to the shafts 12, 3 to accommodate such adjustment. In a method of tack welding ribs to a main plate, the single right-hand rib 22 is pressed against the fixed roller 15<SP>1</SP> by the corresponding movable roller 16 and then tack welded to the plate thereby providing a guide for the jig. The additional ribs 14 are initially placed in approximate positions, as by cranes, the fixed axis roller arms 41 are precisely positioned to locate the ribs 14, the movable axis roller arms 4<SP>1</SP> are roughly positioned so that the rollers 16 press the ribs against the rollers 15, and the devices 19 are energized for the rollers 17 to press downwardly on the ribs. Since this downward pressure tends to lift the jig, the engagement of the wheels 5 is relieved and the jig is driven longitudinally by the roller 15<SP>1</SP>. The tack welding may be effected manually or by a tack-welding device connected to the jig. Several jigs may be contiguously arranged in line abreast and moved simultaneously longitudinally of the ribs. Operation of the motors 7, 8 and pump 18 may be effected by push-buttons.