GB901844A - Tube tapering machine - Google Patents

Abstract

901,844. Making tapered tubes; drawing; stretching. LE FIELL, C. K. July 2, 1959 [July 21, 1958], No. 22787/59. Classes 83 (2) and 83 (4). In a method of tapering a tube radially-inward, forces are applied to localized portions of the tube progressively along its length while the tube is rotated and subjected to axial force of constant or varying magnitude. A tube T is held in chucks 14, 23 attached to spindles 12, 17, which are mounted respectively in a fixed headstock 11 and a travelling tailstock 16 and is rotated by belt drives from a shaft 27. During rotation of the tube a carrier 15 for adjustable dies 31, 32 is traversed along the tube by a ram 50, the dies being at the same time rotated in response to the movement of a follower 57 along a template 58. The follower 57 is biased against the template by a ram 42, shaft deflection of the follower to a neutral position actuating a control valve 44 attached to a rack 40 carried on the piston-rod 41 of the ram 42 so that flow to the upper end of the cylinder ceases. Thus, according to the action of the template 58 on the follower 57, fluid is admitted to the ram 42 to raise or lower the rack 40 to rotate the dies 31, 32 through gearing. Rotation of the dies, which have tapered grooves of semi-circular cross-section, in one direction causes a decrease in the size of the die aperture while rotation in the reverse direction increases the size, the die aperture being adjusted in accordance with the template 58 to effect the registered taper. In order to maintain tne wall thickness constant or to increase or decrease it during tapering, the tube is subjected to a variable axial force by a ram 53 which traverses the tail-stock 16, the fluid supplied to the ram 53 being regulated by a control valve 56 operated in response to the movement of a roller 47 over a template 48. The axial force is usually tensile but may be compressive.