Locking detent for corrugated tube

Claim 1

In a flexible corrugated tube of the type that has a succession of axially displaced convolutions of spirally coiled thin metal strip having longitudinally extending corrugations, the corrugations being of wave form having alternating arcuate axially spaced crests and troughs, the border portions of successive tube convolutions overlapping each other with at least one corrugation in the overlying border portion of one convolution fitting into one corrugation of the underlying border portion of an adjoining convolution, and a plurality of circumferentially spaced detents in the crests of said interfitting corrugations with said interfitting corrugations having said wave form between said detents, the improvement comprising: each of said detents has a flattened central area flanked by crimps along the marginal portions of said central area that extend downwardly and outwardly therefrom substantially parallel to a closely adjacent the lowermost portions of the crests in which said detents are located, so the overlapping convolution border portions are firmly locked into one another in said crimps.