摘要 |
A method of making interlocked metal tube from a strip of the metal of generally S-shaped cross-section by which the shaped strip is formed into a helix without interengaging adjacent coils of the helix, passing the helix without rotation through a rotating driving means to move the non-rotating helix axially, interengaging adjacent coils of the helix and then performing an operation to prevent subsequent disengagement of the adjacent coils, thereby to form an interlocked metal tube. The driving means for the helix is a rotatably-driven mandrel around which the open helix is placed. The mandrel has intermediate its ends a radially-outwardly extending integral portion in which there is a helical passageway forming a tunnel through which the helix is passed and from which the helix is delivered to move without rotation axially along the remainder of the mandrel.
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