Method and device for forming the peripheral beads in a blank of sheet metal, of generally cylindrical form

摘要

1,075,856. Corrugating; tube expanders. METAL CONTAINERS Ltd. Sept. 18, 1964 [Sept. 18, 1963], No. 36834/63. Headings B3E, B3J and B3Q. A method of corrugating a sheet metal cylinder (12) comprises placing the cylinder on a die unit (13, Fig. 3), including radially movable die segments (14), expanding the die unit to form a corrugation, and successively forming further corrugations whilst holding the cylinder by engaging one or more of the corrugations already formed and permitting the unformed portion of the cylinder to move towards the corrugation being formed. The die units may equal in number the corrugations to be formed, each arcuate segment (14) of a unit having a stem (18) guided in a passage (20) formed in a casing (21). The passages are staggered (Fig. 4), so that the segments may be juxtaposed. A roller (19) on the stem (18) is engaged by a core (15) movable by a fluidpressure cylinder (24) to expand the segments against the force of return springs (16) in grooves (17) in the segments. The outer surfaces of the segments are formed by rubber rings (31). The core has a cylindrical guide portion engaging the bore of casing (21) and one or, if the core is to operate in both directions, two tapered ends. Slots are formed in the core which are in axial alignment with the rollers (19), and in the slots are cams (27) adjustable by a screw-threaded conical sleeve (28). As the core moves along the cylinder, the straight portions of the cams retain three of the die units expanded to hold the cylinder as a further corrugation is formed.