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.
In a pipe formed from a helically coiled strip of ductile material having a main body connected along its longitudinally extending edges by a seam, said seam comprising: a. first and second marginal portions respectively along and parallel with said edges having adjacent return bends at opposite sides of a plane extending between and parallel with said bends; b. said marginal portions including flattened loops disposed at the same side of said plane, each extending from one of said bends to substantially the other, with one of said loops enclosed within the other; c. said loops being bent along a line spaced from and parallel with said bends forming a generally V-shaped corrugation in cross sectional contour transversely of said bends with said bends positioned in one of the sides of said corrugation and with flattened portions of said loops extending across and along opposite sides of the apex of said corrugation.
Claim 2
Dependent Claim
152 words
In a pipe formed from a helically coiled strip of ductile material having a main body connected along its longitudinally extending edges by a seam, said seam comprising: a. first and second marginal portions respectively along and parallel with said edges having adjacent return bends at opposite sides of a plane extending between and parallel with said bends; b. said marginal portions including flattened loops disposed at the same side of said plane, each extending from one of said bends to substantially the other, with one of said loops enclosed within the other; c. said loops being bent along a line spaced from and parallel with said bends forming a generally V-shaped corrugation in cross sectional contour transversely of said bends with said bends positioned in one of the sides of said corrugation and with flattened portions of said loops extending across and along opposite sides of the apex of said corrugation.
Claim 3
Dependent Claim
57 words
In a pipe as defined in claim 1, in which d. said main body between said marginal portions is formed with a row of corrugations parallel with said V-shaped corrugation and of substantially the same depth as that of the latter, and said main body joining said marginal portions at the divergent ends of said V-shaped corrugation.
Claim 4
Dependent Claim
43 words
In a pipe as defined in claim 2, in which e. each of the sides of said V-shaped corrugation, including said apex thereof, having at least five layers of the material of said marginal portions, and said layers being continuous across said apex.