Abstract: Apparatus for helically curling longitudinally corrugated thin strip material into a flexible corrugated tube has a curling unit with driven input rollers forming a nip that matches the strip, and a cassette for a reel of the material which is connected to said unit and has strip guide rollers immediately adjacent the input rollers. The curling unit has driven output rollers on an upright support to drive the strip, and a spider which is vertically adjustable on the support and carries strip guide rollers which are on spindles equidistant from the longitudinal axis of the forming tube, and radially adjustable, so that adjustment of the spider on the support and the spindles on the spider permits the unit to form tubes of different diameters. A locking mechanism intermittently crimps overlapping parts of the forming tube. A bending device aids in forming relatively stiff strip stock, and also aids in forming softer stock into very small diameter tubes.

Abstract: A strip of longitudinally corrugated thin sheet metal is spirally coiled to form a tube with adjacent border portions of successive 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 the interfitting crests are provided with circumferentially spaced locking detents each of which has a flattened central area flanked by crimps along its marginal portions that extend downwardly and outwardly in substantial abutment with the lowermost portions of the crests in which the detents are located.

Abstract: A pipe clamp has a U-bolt with legs each of which is provided with first and second tandemly arranged frustoconical circumferential ribs with planar annular bases that define the distal margins of circumferential grooves in the U-bolt legs, and a C-shaped sheet metal saddle having a hollow body portion with inside edges that are separated by a space less than the maximum width of the body portion. The saddle has circumferentially slit extremities each of which has aligned transverse internal flanges with opposed inner margins that define split circular openings which are dimensioned to permit the flanges to snap around the circumferential ribs and engage in the grooves. The U-bolt and saddle are adapted to loosely encircle a pipe when the flanges are engaged in the first grooves, and are adapted to firmly clamp the pipe when the flanges are engaged in the second grooves.

Abstract: A strip of very thin flexible material has continuous longitudinal corrugations in the form of curved ridges and hollows, and may be curled helically to form a flexible tube. The strip has a first marginal ridge with a radius of curvature smaller than that of all other ridges, and a second marginal ridge with a radius of curvature larger than that of all other ridges. As the strip is curled with the first marginal ridge overlying a first intermediate ridge and the second marginal ridge underlying a second intermediate ridge, the marginal ridges are respectively spread over and closed under the intermediate ridges to conform to the curvature thereof.