(under subclass 58) Subject matter comprising a step of, or means for, the formation of two or more axially spaced, substantially identical, annular enlargements in cylindrical work.
(1) Note. For placement in this subclass, a patent should be directed to the combination of actuated tool means and internal fluid pressure means so disposed as to produce a series of substantially similar annular ridges and grooves in tubular work; at least two spaced enlargements of similar form and size distinguishes "corrugating" from the more general inflating or expanding operations of the preceding subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
61+, for expanding hollow work against an external die by fluid pressure within the work.
