GB587785A - Improvements in or relating to tube drawing apparatus - Google Patents

Abstract

587,785. Drawing. STEVENS, A. H. (Bridgeport Brass Co.). Aug. 9, 1944, No. 15146. [Class 83 (iv)] Mandrels.-A tube-drawing mandrel comprises a shank with a forwardly projecting stud which carries a sizing mandrel or sleeve adapted to be displaced longitudinally and also laterally with respect to the axis of the stud. The shank 17, Fig. 3, is in screw-threaded engagement at the rear end with a rod 38 which is guided and held at the rear end of the drawbench and at the front end with a stud 26 formed with a head 27 and an abutment flange 28. Mounted on the stud is a sleeve 32 normally pressed against the flange 28 by a spring 35. The bore of the sleeve is greater than the diameter of the stud so that the sleeve may move laterally to a limited extent when tube sections of non-uniform thickness are encountered. In a modified form, Fig. 12, an enlarged portion 115 at the forward end of the shank is hollowed out to form a skirt 117 extending over the rear end of the sleeve to prevent the entry of tube material behind the sleeve. An axial bore 121 extends through the shank and serves to supply lubricant to the interior of the tube by way of passages 125 and 126. In both forms, the front end of the sleeve is tapered, preferably at 45 degrees and the rear edge is rounded. Preferably, the shank and the stud are of heat-treated tool steel and the mandrel sleeve is of cemented tungsten carbide such as the material sold under the Registered Trade Mark " Carboloy."