Abstract: The flexible corrugated tube is made of spirally coiled thin metal strip with corrugations extending parallel to the longitudinal direction thereof, in which tube at least one corrugation of the one side edge of the one convolution (2) lies respectively in at least one corrugation on the other overlapping side edge of the subsequent convolution (3) and the crests of corrugations lying in each other are pressed down by only a part of the corrugation height in such a manner that the corrugation crests are wider than the corrugation cross-section beneath same.

Abstract: A flexible conduit has an undulating liquid tight inner tube portion and layers of metal reinforcing wound around the tube. The layers include a burst resisting layer adjacent the tube, then traction and pressure resisting layers, and an outer sheath. The undulations in the interior of the tube can be filled with packing or the tube can be lined with a spiral strip to lessen resistance to fluid flow through the conduit.

Abstract: The method of forming tubes from strip in which a complementary rib and groove are spaced apart to each extend longitudinally on the strip and oppositely facing on the said strip characterized by guiding the strip into a helical configuration to overlap the edges of the said strip, and pressing together the overlapping parts of the said strip while maintaining a differential pressure in the direction of feed to force the strip together under such differential pressure.

Abstract: A flexible hose and method for making same, suitable for cleaning swimming pools and general vacuum applications, having contiguous turns of an extruded helical plastic bead. The strip has thin flange and leg members for receiving the bead that provide excellent crush resistant strength in I-beam fashion while providing a high degree of flexibility.

Abstract: Thin-walled metal duct particularly useful for heating and air-conditioning purposes is usually made by grooving, spiral wrapping, and seaming strips of thin metal sheet. The resultant tubular form provides the necessary rigidity to resist collapse of the tubular form. In the past, at least one end of the ribbed tubular ducts have been reformed to permit the ducts to be joined together. The end reforming techniques of the past have resulted in reformed ends having insufficient rigidity and strength to resist the abuse the ducts frequently receive in shipping, storing, handling, and installation.The present product, method, and apparatus provide a ribbed thin-walled tubular duct having reformed ends with rigidity and strength superior to the prior art products. This achievement is accomplished in the present invention by moving more metal into the end portion of the duct prior to reforming the end portion, thus reinforcing the end portion of the duct.

Abstract: A multi-layer, spirally wound tube or pipe product with a substantially smooth inner wall having a single, helical corrugation and a corrugated exterior wall. The pipe has an inner pipe layer consisting of an elongated sheet of flat material curled into adjacent, helical convolutions and an outer pipe layer consisting of an elongated sheet of corrugated material curled into adjacent, helical convolutions about the inner pipe layer. The inner and outer pipe layers share a common helical seam. A single, continuous helical corrugation is located in the inner pipe layer along the helical seam, thereby causing the seam to be located within the single corrugation.

Abstract: A flexible hose comprising a lining layer of substantially impermeable material, a reinforcement structure comprising at least one balanced pair of helically extending reinforcement members embedded in elastomeric material to withstand internal pressure and axial tensile loadings, and radially inwards of at least the reinforcement structure a crush resisting armouring layer comprising at least two helical reinforcing elements nested together and shaped such that contacting surfaces of the elements between the successive turns of the helices are of a substantially frusto-conical shape.

Abstract: The formation of articles using an elongated strip which has on it a series of longitudinally positioned upstanding ribs to form between them a series of longitudinally positioned channels and including connectors, on the strip spaced apart transversely on the strip whereby the strip can be wound helically to form an elongated object with the connectors interengated along a helical line to lock the strip in object form.

Abstract: A length of flexible metal piping includes an interlockably shaped metal band spirally formed into a plurality of winding groups wherein each group includes a plurality of interlocked windings. Each of the winding groups are connected to each other by at least one free winding wherein the leading portion of a first winding is separated from the leading portion of a corresponding subsequent winding and interlocking is prevented for at least one revolution. Each free winding, which constitutes one circumference of the piping, is formed by the insertion of a shaping tool into contact with the leading portion of the free winding prior to the point where this leading portion would normally interlock with the leading portion of a corresponding subsequent winding one revolution later. The shaping tool alters the cross-sectional arrangement of the metal band such that interlocking of that portion of this spiralling band which is contacted by the shaping tool is prevented.

Abstract: A flexible corrugated tube comprising a succession of convolutions of spirally coiled thin metal strip having the overlapping corrugations of adjacent convolutions locked together by a plurality of spaced apart detents about the circumference of at least one of the sets of overlapping corrugations. Apparatus for forming the tube comprises a grooved roller in which at least one of the grooves comprises ridges extending a limited distance from the groove base toward the roller surface.

Abstract: A pipe formed by a helically coiled strip of ductile sheet metal of uniform width connected along its longitudinally extending edges by a seam, which seam is formed by the marginal portions of the strip along said edges. Said marginal portions are formed with parallel return bends extending longitudinally of said edges, which bends are in adjacent opposed relation and which marginal portions include flattened loops extending to the same side of said pipe from approximately one of said bends to the other with one of said loops enclosed within the other, and the said marginal portions are bent along a line spaced from and parallel with said bends to generally V-shape in cross sectional contour transversely of said marginal portions, whereby said bends are positioned in one of the sides of said V spaced from its apex with flattened portions of said loops extending across and to opposite sides of said apex.

Abstract: Corrugated, flexible, metal duct formed of a helically wound strip of lightweight metal characterized by a pair of interlocked U-shaped seam elements which constitute one leg of a common corrugation of contiguous convolutions of the strip and extend radially throughout the length of that leg so that the areas at the base of each U-shaped seam element abuts against the adjacent corrugation leg and is locked against separation thereby. Apparatus which makes such duct through the use of rollers only and void of any mandrel means is also shown.