Patent GB-619683-A (GB)
Title: Drawbench
IPC: B21C1/32
Filed: 1946-05-01
Abstract: 619,683. Drawing. AETNA-STANDARD ENGINEERING CO. May 1, 1946, No. 13312. Convention date, June 13, 1945. [Class 83 (iv)] The bed of a draw bench comprises two spaced longitudinally extending track members upon which the carriage operates forming between them an open unobstructed space through which the drawn tube may fall, one of the members being supported by overhead means so that the space beneath it is unobstructed to permit lateral discharge of drawn tubes. In a preferred arrangement shown in Fig. 1, a bed 10 comprises two longitudinally extending beams 21. 22 supporting toothed track members 23 and 24, Figs. 2 and 8, on which a carriage 15, supported by wheels engaging on the upper surfaces of the members 23 and 24, operates by the engagement of pinions 132, and 133 with the said toothed members, the pinions being driven through bevel gears 124, 126 and 125, 127 and a worm 116 and worm-wheel 118, by an electric motor 115. The beams 21 and 22 are supported by bracket members 29, substantially C-shaped, by means of which the bed is supported entirely from one side, the space beneath the bed being open on the other side. The space between the track members is also open and unobstructed and hence drawn tubes may fall directly through the bed and be guided by the sloping guide members 35, 38 into the containers 37, 40, the alternation of position of the guide member 38 between the two positions shown in Fig. 2 allowing for the separation of work drawn at one end of the bed from the work drawn at the other. At each end of the bed 10 is mounted a die stand 11 and 12, each carrying three dies 18, 19 arranged horizontally, and above them pinch roll mechanisms 70, 71 which facilitate the feeding of tubes from a loading rack 13 over the mandrels of mechanisms 16 and 17. Each of these mechanisms, Figs. 3 and 4, comprises two sets of three mandrels, one set of which is loaded while the tubes carried by the other set are being drawn. The interchanging of position of the two sets of mandrels is effected by mechanisms 55, which are connected by a shaft 58 upon which is mounted a lever 59 between members 57, arranged to be rocked through about 120 degrees of arc by a fluid pressure mechanism 60, there being one mechanism 60 operating the mechanisms 55 of the mechanism 16, and one operating the mechanisms 55 of the mechanism 17. Then as indicated in Fig. 3, rocking of the lever 59 causes the mandrel sets 45 and 46 to take an arcuate path and enables them to pass one another to take up their new positions, the platforms 53 and 54 upon which the mandrels are mounted in the grooved guide blocks 51 and 52 remaining substantially horizontal throughout the movement. The mandrel sets are anchored in the drawing position by the engagement of depending portions 85 of blocks 79 with the lug 90, the block 79 being urged to the anchoring position by the operation of piston rod 85 (Fig. 5). In operation a loaded set of mandrel rods is positioned adjacent one of the die stands, say 11, and the pointed ends of the tubes are fed through the dies 18, gripped by gripper jaws 101, and the carriage operated to draw the tubes through the dies, the upper set of mandrel rods in the mechanism 16 and one of the sets in 17 meanwhile being loaded. When the drawing operation is completed the tubes are automatically released by the gripper jaws and fall between the track members and thence into the receiving rack. The carriage continues its travel to a position adjacent die stand 12 and is then operated in a reverse direction to draw tubes through the dies 19 from the mechanism 17. Meanwhile, the positions of the mandrel rods in mechanism 16 are interchanged to bring the loaded mandrel rods into position adjacent to die stand 11 in readiness for the next cycle of operations. In a modification there may be a die stand at one end only, when the carriage may have only one set of gripper jaws, and the die stand or die stands may carry one or more dies. Figs. 11, 12 and 13 (not shown) illustrate a modified form of carriage in which only one set of gripper jaws is fitted, although two may be provided, and the track is of slightly different form, no wheels being fitted. Supply to the electric motor is effected by trolleys 140 and 141 in ducts 137 and 138, of conventional design and a limit switch 142 may be provided. Specification 619,753 is referred to.