Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
  • B21D22/28—Deep-drawing of cylindrical articles using consecutive dies

Definitions

• the present invention relates to a method for deep drawing, the method comprising the steps that a workpiece of sheet metal is clamped between a first drawing die and a tool holder, that a first punch moves the workpiece through the first die during a relative forming movement between the punch and the die so that the workpiece is converted into cup shape, that the transverse dimension of the workpiece is reduced and its longitudinal dimension is increased in at least one reduction step in that the workpiece is, under the action of a second punch of smaller transverse dimension than the first, is moved through the second die in a relative forming movement between the punch and the die, and that the reduction step is possibly repeated, use being made of a third, a fourth, etc., punch of smaller transverse dimensions than the preceding punch, and a third, a fourth, etc., die.
• the present invention also relates to an apparatus for deep drawing, the apparatus comprising a first drawing die and a tool holder cooperating therewith for clamping a workpiece therebetween, a first punch for pressing the workpiece through the first die, at least one second punch of smaller transverse dimensions than the first, and an associated second die for reducing the transverse dimensions of the workpiece and increasing its longitudinal dimensions, possibly a third, a fourth etc., punch of smaller transverse dimensions than the preceding punch, and a third, a fourth etc., die for further reducing the transverse dimensions of the workpiece and increasing its longitudinal dimensions, and a movement device for setting the punches in relative forming movements in relation to their respective dies.
• a planar workpiece manufactured from sheet metal is placed between a die and a tool holder and is clamped fast between them.
• a punch drives the workpiece through the first die so that the workpiece is converted into cup form.
• the workpiece is removed from the work station, transported to the second and placed in the correct position therein.
• the last reduction step may, after the last reduction step, possibly be a step in which the finished, deep drawn workpiece is cut clean along its periphery.
• a transfer press may give a satisfactory technical result as regards the deep drawing proper, but the time consumption is far too great in long series, since, on the one hand, the length of movement between the drawing dies, ar ⁇ L_corresponding.iooL holders must be long in order to permit removal of the processed workpiece and, on the other hand, because the workpiece must be displaced mechanically from one working step to the next.
• a machine for carrying out such a deep drawing has a first drawing die and an associated tool holder as well as a first punch disposed on the side of the tool holder. After closing of such a tool so that the workpiece is fixedly clamped between the tool holder and the first drawing die, the workpiece is drawn "in the wrong direction" under the action of the first punch. Simultaneously herewith, a second punch will hit the central region of the workpiece but in the opposite direction. After this working step, the workpiece has a central bulge in one direction and a circumferential edge portion in the other direction.
• the first punch works as a tool holder while the interior concentrically in the second punch carries out a second deep drawing process which converts the workpiece into cup form.
• This second drawing process takes place "in the correct direction”.
• this second drawing process "in the correct direction”, there may follow a reduction which is carried out by a third punch.
• the present invention has for its object to design the method and the apparatus for carrying out the method as intimated by way of introduction such that the drawbacks inherent in the prior art technology are obviated.
• the present invention has for its object to design the method and the apparatus such that the time consumption for a complete deep drawing cycle may be greatly reduced at the same time as the quality and surface finish of the deep-drawn product may be improved.
• Fig. 1 is a schematic vertical cross section through a vertically operating apparatus for carrying out the deep drawing method according to the present invention
• Fig. 2 is a cross section corresponding to that of Fig. 1, the included components having been brought to a position where a workpiece is fixedly clamped between a first drawing die and a tool holder;
• Fig. 3 is a section corresponding to that of Fig. 1, the first drawing process having been completed;
• Fig. 4 is a section corresponding to that of Fig. 1, the first reduction stage having been completed.
• Fig. 5 is a section corresponding to that of Fig. 1, the last reduction stage having been completed and the processed workpiece is under the return stroke ready for discharge.
• reference numeral 1 relates to a press table disposed in a press, the table being stationary in normal operation.
• the broken line 2 intimates a press slide which, injiqrmal orjeratipn,_is reciprocal towards, and, awayjrom the_press tableJL._JruEig.-l, the press slide is shown in a starting position prior to the completion of a working stroke.
• Fig. 1 refers to a vertical section through a vertically operating press, but the present invention may just as well be applied in a recumbent press where, in such an event, the press slide 2 would move towards and away from the press table 1 along a horizontal path of movement instead of, as in Fig. 1, via a vertical path of movement.
• a tool holder 3 is disposed on a plate which, via a number of push rods 5 disposed annularly concentrically about a centre shaft is connected to a counter plate 6 which in turn is connected via a rod 7 to a counter holder device 8 in the form of a hydraulic cylinder where the rod 7 may act as the piston rod or ram of the cylinder or an extension thereof.
• a first punch 9 is disposed on a plate 10 which, via annularly disposed push rods 11, is connected to a counter holder plate 12 which in turn, via a number of rods 13, is connected to the counter holder device 14.
• the arrangement of the counter holder plate 12, the rods 13 and the counter holder devices 14 is completely analogous with the arrangement of the counter plate 6, the rods 7 and the counter holder devices 8.
• a second punch 15 is disposed concentrically interiorly in the first punch 9 which is tubular and rests on a plate 16.
• the plate 16 is connected via a number of push rods 17 to a counter plate 18 which, in turn, via annularly positioned rods 19, is connected to counter holder devices 20.
• the arrangement of the second punch 15, its plate 16, push rods 17, counter plate 18 and rods 19 which connect the counter plate to the counter holder devices 20 is completely analogous with that described above.
• a rigid unit with a first drawing die 22, a second drawing die 23 and a third drawing die 24.
• the drawing dies 22-24 are disposed with mutual axial spacing, and the distance between the uppermost or last drawing die 24 and the press slide is sufficiently great for a ready-processed workpiece 25 to have room therebetween and be discharged out in the lateral direction.
• suitable spacer rings are provided, and between the uppermost drawing die and the press slide there are disposed spacers 26 of requisite height.
• a gripping device 27 which is intended to grip about the periphery of a ready-processed workpiece and retain it in the intended position at least during the return stroke of the punch 21 which had carried out the final forming of the workpiece.
• the above-mentioned spacer rings between the drawing dies 22-24 have circular apertures where there is formed, over the first drawing die 22, a space 28 which is sufficiently large to be able in itself to accommodate the first punch 9 and a cup- formed workpiece 32 (Fig. 3) positioned thereon.
• a space 29 which is dimensioned for accommodating the second punch 15 ⁇ wjth_a_workpiece_ positioned thereon after this punch has completed its reducing work stroke.
• Fig. 1 is shown the apparatus 1 in a starting position before a work stroke. Li this state, a planar workpiece of sheet metal is inserted between the tool holder 3 and the first drawing die 22, whereafter the rigid unit which, int. al., includes the drawing dies 22-24, the spacer rings and the spacers 26 is moved under the action of the press slide 2 in a downward direction so that the planar workpiece is clamped fast between the first drawing die 22 and the tool holder 3.
• the workpiece carries reference numeral 30. In this state, the clamping of the workpiece is adjusted by the counter holder devices 8.
• the press, slide 2 has been displaced a distance downwards towards the press table 1 and, in such instance, has forced down the rigid unit about the first punch 9 so that this and the workpiece are now located in the space 28 and their upper end located immediately ahead of the second drawing die 23.
• the workpiece carries reference numeral 32 and has been converted into cup or beaker form.
• the first punch 9 and the associated plate 4 will continue their downwardly directed movement towards the press table 1.
• the second punch 15 will move the workpiece through the second drawing die 23 until the workpiece is wholly located on the upper side of the second drawing die 23 and is thus positioned in the space 29 between the second drawing die 23 and the third and, in this embodiment, last drawing die 24.
• the associated plate 16 of the second punch 15 has been urged downwards, since the associated plate 10 of the first punch 9 will have come into abutment against its upper side. This situation is reflected in Fig.
• the gripping device 27 retains the finished workpiece 35 when the third punch 21 has been withdrawn. After release of the gripping device, the workpiece 35 is discharged laterally. This may possibly be put into effect simultaneously with the rigid unit being raised under the action of the press slide 2.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (2)

Citations (4)

• 2005
  • 2005-02-23 SE SE0500412A patent/SE528280C2/sv not_active IP Right Cessation
• 2006
  • 2006-02-23 WO PCT/SE2006/000236 patent/WO2006091152A1/en active Application Filing

Patent Citations (4)

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