| 摘要 |
<p>PURPOSE:To easily manufacture the conduit wherein a wire rod for communication is inserted by using pressure liquid and to improve the insertion characteristics by curving a flat type metallic plate, which has ridge stripes lengthwise on its surface to be the internal surface of the conduit into a tubular shape, and welding the contacting surfaces. CONSTITUTION:The flat type metallic plate 11, which has the ridge stripes lengthwise on the surface to be the internal surface of the conduit 12, is curved into the tubular shape and the contacting surfaces are welded together. Namely, the metallic plate 11 which has the ridge stripes cut is supplied from a metallic plate supply 15 and rounded into the tube by a tube maker 13 and their connection surfaces are welded by a welder 14 to form the conduit 12, which is taken up around a take-up reel 16. Each process can easily be carried out, so the groove width and depth of the finished conduit are obtained as designed since the operation for cutting the grooves in the metallic plate is carried out with sufficient accuracy. Consequently, the accuracy of the machining is high and the conduit can be manufactured so that the configuration of the ridge stripes matches the design.</p> |
