GB424065A - Improvements in or relating to the manufacture of tubes or hollow bodies by drawing - Google Patents

Abstract

424,065. Making tubes &c. ROBER, E., 28, Alte Landstrasse, Kaiserswerth, D³sseldorf, Germany. Aug. 18, 1933, No. 23101. Convention date, Feb. 13. [Classes 83 (ii) and 83 (iv)] A blank b is pushed through dies a and /or rolls by a mandrel d which is pushed forward by mandrel rod f in the form of a closed ended tube which slides over a plunger i when fluid pressure is admitted to the tube f, the tube f being thereby under tension and so free from any tendency to bend. The tube f has a small end extension e which fits into the mandrel d and has a gland h at the other end. The plunger i, Fig. 3, and the tube f are supported by levers o held against them by tension springs p. The gland h, Fig. 4, has external ribs n sliding in grooves m in the guides l. Rollers g are driven to withdraw the mandrel rod f from the work, the fluid then being sucked out of the tube. In Fig. 5, the hydraulic pusher t is of too large a diameter to pass through a succession of dies q so each die is released from its holding bolts z by an extension rib u on the pusher t operating levers bb to force back the bolts z holding the die so that pins dd on the pusher can enter holes in the die and carry it along. The die holders have spring friction bushes ee to slide over the bolts dd and so remain thereon as they collect on the cone S. In Fig. 6 a winch w winds the pusher back. On return of the pusher the dies are also replaced and refixed in position automatically. To facilitate stripping the 3rd and 2nd last dies have clearance passes as in Fig. 13, and the last die has a circular pass Fig. 14 so that the tube is separated and freed from the mandrel. The means for releasing the dies from their positions and replacing them may also be applied to a pusher operated by rack and pinion. When rolls are used they are driven through a free-wheel device to allow over-run by the pusher.