GB757888A - A new or improved method of producing duct members - Google Patents

Abstract

757,888. Making drain traps or other bent duct members; stamping. BENDZ, Ltd., and ACKERMAN, S. Jan. 22, 1953 [May 23, 1952], No. 13069/52. Classes 83 (2) and 83 (4). A method of producing a duct member of other than simple rectilinear form, such as an angle bend or U-shaped drain trap, includes acting on a length of duct by a cold deformation process of such character as to produce the required longitudinal configuration, trimming at least one end portion of said deformed length to produce a rim which lies in a plane substantially perpendicular to the centre line of the duct, and pressing said trimmed end. portion locally to produce an internal circumferentially extending recess adapted to receive a sealing ring. To form a drain trap, Fig. 1, a length of metal duct 20 is given a first bend by apparatus, Fig. 8, wherein the duct or tube 20, disposed over a mandrel 18, having an articulated end 26, and held in a fixed guide 17 and pivoted member 23, is bent around a curved part 21 of the pivoted member 23 as that member is swung around its pivot. One limb of the bent pipe is then bent to form the U-bend by similar apparatus, the pivoted member 23 of which being suitably shaped to hold the elbow part of the pipe. The end of one limb is then trimmed off and pressed to form a flange 47, Fig. 1, which serves to retain a union nut 48. The end of the other limb is also trimmed off perpendicularly to the axis of the pipe and the bent and trimmed pipe is held by shaped clamping dies 52, 53, Fig. 4. A succession of punches, in co-operation with a shaped end of the dies 52, 53 form an enlarged end 60 of the pipe and, by curling, a circumferential internal recess 70, Figs. 5, 6 and 7. A rubber sealing-ring 72 of circular, elliptical or oval cross-section is inserted into the recess so as to project slightly therefrom to form a fluidtight seal against the end of another pipe 59. Before the ring is placed in position the trap may be pierced at the bottom of the U and an internally-threaded sleeve 73, closed by a screw plug 74, secured thereto. The recess 70 may be of rectangular, V-shaped or part-circular crosssection. According to the Provisional Specification the bending and recess-forming operations may be carried out simultaneously. Specifications 757,884, [Group XXVIII], and 757,976 are referred to.