摘要 |
A welding apparatus (24) is adapted to be mounted on a guide ring, the welding apparatus comprising a housing (25), a pair of rollers (29, 31) mounted on each side of the housing, said pair of rollers comprising a first roller (29) having a tubular outer surface and a second roller (31) having a conical outer surface, the pairs of rollers being mountable on either side of a guide ring such that an edge of the guide ring passes between each pair of rollers, the conical roller (31) on one side of the housing being laterally movable within the housing (25). |