Patent GB-594170-A (GB)
Title: Drawbench
IPC: B21C1/32
Filed: 1945-06-08
Abstract: 594,170. Drawing. AETNA-STANDARD ENGINEERING CO. June 8, 1945, No. 14582. Convention date, June 16, 1944. [Class 83 (iv)]. Mandrels.-Apparatus for drawing tubes comprises a drawbench with a carriage for pulling a tube through a die and at least two mandrel rods which can be moved so that when one is in alignment with the die the other is in a loading position out of alignment with the die, the mandrel rods being at all times parallel to each other and to the axis of the die. The drawbench is of conventional form comprising a die stand 10, and a track 11 along which a carriage 12 with gripping jaws is moved by a chain 13, Fig. 2, in known manner. In one form, four mandrels are provided carried at the ends of mandrel rods 20, 21, 24, 25. The rods are parallel to the axis of the bench and are mounted in a series of axially spaced rotatable carriers 33. Supporting or guiding tubes 29, 30, 31 and 32 surround the rods for the greater part of their length. Each carrier 33 is supported by three rollers 34 and has peripheral gear teeth 37, Fig. 4, by which it is rotated through 180 degrees from a common shaft 43 driven by a motor under the control of the operator. At the rear end of the bench the mandrel rods are anchored to a holder 28, Fig. 7, also rotated by the shaft 43 through an elongated gear 47, while the spindle 45 of the holder is slidably mounted at 48 and may be moved axially by a fluid pressure cylinder 51 so as to move the mandrel rods axially to and from the dies. Two dies are provided, these being located in alignment with the mandrels in the two lower positions as shown in Fig. 4, stop members 53, 54 and 55 ensuring accurate location of the carriers 33. At the position marked 15 in Fig. 2 are the uprights 61 of means for lifting the tubes to be drawn on to a platform and where they are engaged by a pusher 79 and moved, with manual guidance, over the two upper mandrels. The mandrel rods are then moved rearwardly and the carriers rotated so that the two loaded rods are brought into alignment with the dies. The mandrels are then fed forwards so that the ends of the tubes, which were pointed before being loaded on to the rods, are pushed through the dies ready to be gripped. by the draw carriage 12. While the drawing proceeds, two other rods are fed on to the rods in the upper position. The various parts of the apparatus are operated by separate motors under the control of an operator at the die stand. In a modification six mandrels are provided, three of them on rods 110 within tubular supports 114 being at the upper station and three on rods 111 in supports 115 being at the lower station opposite three drawing dies. The mandrel rod supporting tubes 114, 115 are held by clamps 116 within a tubular member 105 built up from lengths of steel pipe rotatably supported in a number of axially spaced bearings 108. Openings in the member 105 allow access to the clamps 116 which are preferably arranged adjacent a bearing 108. The rear ends of the mandrel rods are coupled to enlarged extensions 123 slidably supported in threaded sleeves 125 mounted in semi-circular plates 131 which may be moved axially by fluid pressure cylinders 141 so as to advance and retract the rods. Two plates 131 and two cylinders 141 allow the upper and lower groups of rods to be operated independently. The mandrel. rods are tubular and lubricant is supplied to the bores through flexible pipes 133, manifolds 134 and flexible pipes 136, the pipes permitting the axial advance and retraction of the rods and also the 180 degree rotation of the members 105 without interrupting the fluid. connection. Rotation of the tubular member 105 is effected by means of two chains 157, 158, Fig. 20, secured to lugs 155 and 156 respectively on the member and to lugs 159 and 160 respectively on a drum 161 of the same diameter as the member 105. A pinion 169 keyed to the shaft of the drum is rotated by a toothed segment 168 rocked by an arm 167 secured at 166 to the piston rod of a compressed air cylinder 164. The tubes are fed from the loading rack on to the mandrel rods by means of pinch rollers, one of which is driven by an independent electric-motor.