Dec. 17, 1946. J, KELLER ‘ 2,412,813 DEVICE FOR MANUFACTURING THIN-WALLED CONTAINERS OPEN 'AT ONE END ‘ Filed Aug. 31, 1944 ‘ ‘ A B. l C f, D _ 4 00/0 33° = 7‘/.?6 INVENTORJ , Jakob Keller Patented Dec. 17, 1946 ‘ “2,412,813 UNITED‘ STATES PATENT. OFFI‘C 2,412,813 ' . h l ' DEVICE FOR MANUFACTURING THIN gl’éilglLED CONTAINERS OPEN AT ONE 1 ‘ Jakob Keller, Zurich, Switzerland Application August‘31, 1944, Serial No. 552,019 ‘ In Switzerland May 3, 1944 2 Claims. byContainers deep (Cl. 113—49) 2 open at one end are already made die C is separated from the first ring B by dis are cylindrical in shape is a circular tance-ring f. and the interval between them is tin disc, which is drawn by a draw-punch through such that the upper edge of the can, whose depth is now b, is still engaged in ring B, when its bot tom already penetrates into ring C. The depth of the can-previouslyequal to b—-is in the same way increased by its passage through ring C to c. In like manner the action of the third ring die a manner that the thickness of the walls is re duced while the container is drawn out by a single puncheon. , This process can be successfully exploited for D draws the depth 01’ the can from c to d. The materials with a high degree of toughness, while 10 thickness of the two distance-rings f and f’ sel? arating ring dies B,‘ C the manufacture of containers open at one end and D. is determined by ' the increment‘of the depth of the can, which is . in turn proportionate to the decrease of the thick ness of its walls caused by each drawing process. process instead of the cold-draw 15 In Fig. 2 die A, ring dies B, C and D, as well as’ ing process for aluminium containers. None of distance rings f and f’ and stripping-ring a. the devices and procedures proposed offers, how are combined in holder h to form the deep-draw ever, the possibility of manufacturing in a single ing tool which is the object of the invention. operation containers with walls only a few tenths At the instant the container enters the ?rst of a millimetre thick. This will be easily under 20 ring dies, the material to be formed has the same . stood if it is realised that in deep drawing the speed as the punch. It can be demonstrated forming stresses must be taken up by mathematically that when leaving the ring the itself, and in tin retains the speed of the punch, but that the a millimetre thick cannot be obtained. The invention hereafter described solves the 25 30 35 the container on entering the next ring. In the accompanying drawing, Fig. 1 depicts 40 the arrangement of the single ring dies, while Fig. 2 is a cross-section of an example of the de unnecessarily increased. vice with three ring dies. The following is a de After its passage through the first ring die. scription of the invention in greater detail in 45 the depth of the container is increased in pro relation to the drawing. a portion to the reduction of the thickness of its Punch 8, which is precisely cylindrical, forms walls. If it is now allowed to enter the second with die A and rim~holder a a drawing tool, which does not differ from the tools of this type already in use. It follows that can E, with a 50 depth equal to a, is produced in the usual way. leaving the ?rst‘ ring collides with that ?owing Before its open end leaves the drawing surface of die A, can E (whose depth is a) is carried by back; again breakage is unavoidable. In conse quence the interval must be such that the con punch S into ring die B which draws the wall of the can to a depth equal to b. The second ring 55 tainer enters the second ring die only when the / work of the ?rst ring die is almost terminated. 2,412,813 . 3 ium can be shaped under the effect of this strain, have the useful function of loosening the wall of the can from the punch. ' not only with exceptional ease, but also v very ' uniformly. f ‘- More important than thisfloo'sening] action, is, however, theyg'uiding in the second ring die.‘ The purpose of the process to which the invention evenv negligible, ‘deformations. ‘On the small as possible. 'A limited degree of overlap ping of successive operations offers the further advantage of a process smooth and free from shocks; and it is obvious that, owing to the thin ness of the container’s walls, even‘ slight shocks ' _' . ‘ Thorough experiments have proved that‘the containers open at one‘ end, in which the raw material is drawn in the usual manner by a sin isstillwithin the upper part of the deep-draw— ing die, and that the successive ring dies are ar 20 ranged at intervals from each other equal to at best results are obtained with a pressure arising through an interval between the rings v10% smaller than the corresponding, depth of the can. Particularly favourable ‘results have been achieved in the manufactureofaluminium cans. This is most probably due to the fact that in the _ process to which the invention relates shaping is " e?‘ected simply by the strain caused-by-the re ‘ gle punch‘first through a, deep-drawing die and then through a. series o? ring dies, all of the ring dies being of uniform internal diameter, said de vice characterised in that the first ring die is so ?tted that the container, on entering this ring, terest that the stroke of the punch should be as v y 10 ' 1. ‘A device for manufacturing thin-walled other 7 hand, vto increase the working speed, it is of in result in breakage. I Essential for the success of the process isalso ‘the pro?le oi the, ring dies. Repeated experi- > ments have proved that the best results are achieved. with a lateral angle of 10:3". ’ relates is'the manufacture ,orcontainers with vwalls a few tenthsof aimillimetrenv thick. The centering tolerance- is, in consequence, of the order of 1/100 Imm., i'.. e. of the orderoffsr'nall, and 4 ciprocal action of ring and punch; and alumin . The slight pressure that still occurs will then least 90% of the depth of the container at the en- ‘ trance to the next ring. , 2, A device according to claim 1,'_characterised in that the ring dies have a lateral angle of 10:3? ?aring outwardly from their bottom to their top surfaces. -' - ‘ JAKOB KELLER.