| 摘要 |
Apparatus for forming a plastics coated metal tube comprising means for forming a continuous strip of metal into a U-shape and a forming sleeve for folding the strip into an overlapping tube. A mandrel (23) is also provided which extends through the forming sleeve and through a locating sleeve (30). The locating sleeve (30) centralises the tube as it passes over the mandrel and welding means are provided for welding the overlapping tube as it passes through the locating sleeve (30). According to the invention, the welding means comprises an ultrasonic welding wheel (32) and drive means for the welding wheel, the drive means being capable of driving the welding wheel (32) at a peripheral speed identical to the speed at which the overlapping tube is drawn past the wheel. |
