摘要 |
A machine for manufacturing circular section helical wave-guides and providing simultaneous calibration of the bore of the helix and snug fitting of the screen around the helix. The helix is loosely fitted in an enveloping tube and both tube and helix are drawn through a reducing die for drawing the tube down onto the helix. The bore of the helix is established by a mandrel and the outer surface of the helix is softened just before entering the die whereby the helix is welded to the inner surface of the tube. |