US2163517A - Press for the flawless deforming of flat blanks - Google Patents

Description

June 20, 1939. L. OECKL El AIL 2,163,517

PRESS FOR' THE FLAWLESS DEFORMING 0F FLAT BLANKS Filed Feb. 4, 1938 5 Sheets-Sheet 1 l/wenfora:

Ludwig oeckl and Erhar MCIIer' June 20, 1939. 1.. OECKL El AL 7 2,163,517

PRESS FOR THE FLAWLESS DEFORMING OF FLAT BLANKS 7 Filed Feb. 4, 1938 5 Sheets-Sheet 2 seam Inventors: Ludwlq Deck) and Erhard Mal/er by a H vh-a/ww,

A'forney.

June 20, 1939. L. 'OECKL El AL 2,163,517

PRESS FOR THE FLAWLESS DEFORMING QF' FLAT BLANKS Filed Feb. 4, 1938 5 Sheets-Sheet 3 1 n fir" mum N a H \m-m A ama Ur LEM Y b June 20, 1939. OECKL ET AL I PRESS FOR THE FLAWLESS DEFORMING OF FLAT BLANKS Filed Feb. 4. 1938 5 Sheets-Sheet 4 lnventom': 9 Oeckl W1 Erhard M0 New by 0'' mm,

Ludwi Attorney June 20, 1939. L. OECKL El AL PRESS FOR THE FLAWLESS DEFORMING OF FLAT BLANKS Filed Feb. 4, 1938 5 Sheets-Sheet 5 mi e 1110!; O a Ck anA Ludwig Erhar b coal 0.. WM,

0! N O'ller- After-n51.

Patented June 20, 1939 UNITED STA-res -mass ron 'rnn FLAWLESS DEFORMING or FLAT nmnxs Ludwig Oeckl, Dessau, and Erhard Miiller, Es-

slingen-Neckar, Germany,- assignors to the fl Henschel Flugaeug-Werke A. G.,

' 'I'eltow, Germany Schoneleld,

Application February 4, 1938, Serial No. 188,802

. In'Germany apt-n 14,1936

9 Claims. (01.113-38) If a press is used for converting substantially fiat blanks, particularly. metal sheets, into the form of hollow bodies, this has the disadvantage that heavy wrinkles arise, particularly at the edge of the hollow body, and undulations form at its bottom. y

For preventing the. formationof wrinkles, special wrinkle restrainers have already been proposed, which, however, are very expensive, be-

cause they must fit exactly to the tool, such as punch and/or die. It has also been endeavored to obviate the formation of undulations by allowing the press to exert a particularly high final pressure. This high final-pressure is required.

above .all, in the case of drawn parts which, in

the finished condition, have a flatunstrengthened form, exhibit grooves or some kind of sharp impressions, or the material of which is to be compressed during dr'awing to provide strength. The

higher final pressure, which is considerably above the actual drawing pressure, necessitates a very powerful and consequently expensive construction of the press.

If the heavy deformation of the metal sheet is efiected only by percussive action withthe aid of a drop hammer, th'en breaking of the metal sheet usually occurs.- Moreover, in this case, the

' formation of wrinkles is not always avoidable.

The percussive pressing action, however, pro- 0 duces in a simple manner very high, final'pressures for shaping the work-piece into the desired form of work-piece.

The object bf the invention is to avoid the disadvantages of both methods of iorming, while retaining their advantages. According to one feature of the invention, the metal sheet or other flattened work-piece or blank is preliminarily drawn or pressed by a slow pressing operation to a form which exhibits only small wrinkles or none 0 at all, and is then brought to the final hollow form by percussive action of the pressing member. The uniform small wrinkles which sometimes arise during the slow preliminary drawing are smoothed by hand, for instance, with a wooden 4g hammer, before the percussion. During the percussive conversion of the work-piece into its final form, wrinkles no longer arise and also no cracks are formed. The percussive treatment has the effect, in addition, that the pieces produced per- 50' manently retain their form, receive sharp contours of the swage and have a well-compressed material structure.

By practice of the new invention, hollow bodies of any desired depth can be manufactured with- 65 out diificulty from sheet metal or the like, which nated in a heavy tool-holder which is provided with the upper swage and to which both a slowlypressing and freely-falling movement can be im- 15 parted. The upper tool can, thus deform the work-piece, firstly, by pressing it under the action of the pressing force and then by striking it. As a result' of the invention, drawing presses need be constructed only with the actual drawing pres- 20 sure that is necessary. Due to the weight and .drop of the tool-holder,'a great percussive energy is obtained, which has to be withstood by only the lower part of the press, while the upper part of the press, which is provided with the drive, 25 has to withstand merely the stressesarising from the actual drawing work.

Several constructional examples of the press are illustrated diagrammaticaly in the accompanying drawings, in which: 7 Fig. 1 shows a press operated hydraulically or by compressed air..

Figs. 2-14 illustrate presses in which thepiston, piston rod; and to l-holder areconnectedtogetner so that they can be decoupled. In these figures, 35 Figs. 2 and 3 show a press with a piston and rod which are rotatable for the purpose of couplin Figs. 4 and 5 show a press with a bolt-coupling.

Figs. 6 and '7 show a press with a claw-coupling.

Fig. 8 illustrates a press with an independently movable hold-down which also guides the toolholder.

Fig. 9 shows a press with a resiliently-mounted hold-down.

Fig. 10 shows a press withanindependentlymovable hold-down which also guides thetool-holder, and an adjustable lower die. 5

Figs. 11 to 14 show respectively an eccentric press, a crank press, a screw press and a toggle-, lever press.

In Fig. 1, numeral l indicates the press frame with the lower swage 2 at the bottom and the 5;;

cylinder 3 at the top, containing a piston rod 4. having a piston 5 connected thereto. The rod 4 terminates in a heavy tool-holder 6, which carries the upper punch or die I. 8 denotes the substantially flat work-piece or blank which is to be deformed. The liquid or gaseous pressure medium for imparting a pressing movement to the rod 4 is supplied and discharged by means of a control (not shown) through the conduit 9 above the piston 5. I0 is the supply and discharge conduit for the pressure medium for lifting the rod 4. ll denotes a conduit having a large crosssection in order to make it possible suddenly to discharge from the cylinder 3 the pressure medium below the piston 5. The conduit l0 may coincide with the conduit ll, if control members are provided for slow and rapid flow of the pressure medium.

The press operates as follows: By admission of the pressure medium above the piston 5, the rod 4, tool-holder 6 and upper die'or punch l are moved with a pressing movement against the work-piece 8, which is thereby preliminarily par tially drawn into its hollow form. The parts are thenreturned by the admission of pressure medium below the piston 5 and any wrinkles in the work-piece 8 are smoothed by hand-working. Now, by opening the conduit II, the pressure medium below the piston 5 is suddenly allowed to discharge from the cylinder 3, which results in the free fall of the rod 4 and the heavy toolholder 6 with the upper punch or die 1., The work-piece is thereby converted percussively with great pressure into its final form. By re-admission of pressure medium below the piston 5, the rod and upper tool carried thereby are again brought into the initial position.

The above described mode of operation applies equally to the presses hereinafter described, the particular feature of which consists in that the guided tool-holder is connected to the piston rod of the press by a manually or mechanically disconnectable coupling, so that it can be decoupled,

the coupling acting only between the rod and tool-holder, so that the decoupling of the latter can be efiected in any position of the rod.

In the press according to Figs. 2 and 3, the tool-holder 6a is independently guided at suitable parts of the frame I and forms a part of the rod 4 which can be decoupled. The coupling consists of bosses 2 arranged at the enlarged foot of the rod 4 and having an embracing arc of about 60, which, on the one hand, can pass through between corresponding projections l2a, of the tool holder 50 and, on the other hand, can engage under these projections l2a. The coupling and decoupling are eflfected by progressive 60 rotation of the rod 4, which can be effected by hand, for instance, by-means of a lever l3 (indicated in dotted lines), or mechanically. The mechanical'arrangement consists, for

example, of a worm-wheel l4 rigidly connected to the rod 4, worm l5, electric motor l6 and current source H. The motor- 16 is mounted on a yoke l8 guided in the press and carried by the rod 4. l8 denotes an electric contact which closes on mounting the foot of the rod on the tool carrier and which serves for starting the motor IS.

The preliminary drawing of the workpiece 8 by pressing movement of the members 4, 6a and I coupled together and the return of the members to the initial position are effected in the above-described manner. If the upper tool I is to have a percussive action, then the-rod 4 is rotated by 60 by switching on the motor I5 for example, by hand, whereby the coupling I2, I21: is released and the tool-holder 6a with the tool 1 descends freely and effects the final deformation of the work-piece 8. The rod 4 is made to follow by corresponding control of the conduits 9 and I0 and comes to rest with its root on the toolholder lia. Thereby, the contact I!) closes automatically, which results in starting the motor l6 and coupling together the members 4 and Ed by rotation of the rod 4. Thereupon, the rod 4, tool-holder and tool are returned, the initiation of this movement being automatically controllable, for example, by the rod 4.

In the construction according to Figs. 4 and 5, the coupling arrangement consists of bolts 2! which are displaceable in the foot 20 of the rod 4 and which can engage behind a carrying piece 22 of the upper tool holder 60.. The bolts are driven hydraulically or pneumatically with the aid of pistons 24 moving in cylinders 23, in which case, for instance, the same pressure medium is employed for the cylinders 3 and 23. The mode of operation of the press corresponds to that of the construction according to Figs. 2 and 3. The pressu medium conduits belonging to the cylinders are, for instance,- telescopically displaceable tubes or'flexible tubes 25, 26. In this case also, the coupling movement of the bolts 2| after the descent of the rod 4 has terminated may be automatically controlled by a striking body or abutment 21 acting, for instance, on a valve, whereby the pressure-medium supply or discharge through the conduits 25, 26 is regulated. The bolts 2| may also be driven by solenoids or magnets.

In the form of construction according to Fig. 6, the tool-holder 6a has a coupling projection 28 behind which can engage two lugs 30 which are displaceable on slides 29 at the piston rod foot 20. .For effecting the displacement the slides 29 are coupled to levers 3| which are driven by piston rod 32 with piston 33 which moves in a pressure-medium cylinder 34 in the hollow rod 4. Pressure-medium conduits 35 are indicated schematically. By displacement of the piston 33 in one or the other direction, the tool-holder 6a is released from the rod 4 or coupled thereto. Here also, as in the previous case, the control of the coupling and of the return movement of the rod 4 can be automatically effected by means of suitable members 21.

Fig. 7 shows an electro-magnetic coupling arrangement, in which the core 31 of a solenoid 36 arranged in the rod 4 is connected to two doublearmed levers 39, pivoted at 38 in the rod foot 24 and carrying lugs 30. On the solenoid being energized and its core 31 attracted, the lugs 30 engage behind the projection '28. Whenthe solenoid is deenergized, the coupling between the rod 4 and the upper tool carrier 6a is released. 19 is the electrical contact co'iitrolling'"the coupling,

Figs. 8-10 illustrate a press operating with a pressure'medium, in which the rod 4 is moved by the pressure medium only into the pressing position, whereas forits return, a separate piston 4a is provided in a cylinder 3a arranged above the cylinder 3, the piston 4a being connected by rods 3| to the rod-foot 20. 39a denotes a suitable, manually or mechanically operated coupling between the rod-foot 20 and tool-holder 5a. It consists, for example, of double-armed levers pivotally mounted in the rod-foot 20. one arm of each lever engaging, in the coupling position, under a. roller of the tool-holder, while the other arm is pivotally connected to a driving device which is operated, for instance, by the pressure medium.

According to Figs. 8 and 10, the tool-holder 6a is guided in a lower holder 40, which is driven by plungers 4| and which can be moved up and down on guide pillars 42. The plungers 4| provided with pistons move in p'ressure medium cyl-- inders'43.

After placing the work-piece in the press according to Fig. 8, the hold-down 4!! and the upper tool carrier tal are run down successively or simultaneously, whereupon after application of the hold down to the lower tool 2, the preliminary drawing is effected by tool 'I. By means of the restoring device 3a, 4a., 38, the rod 4 and the tool-holder 6a are then lifted and separated by release of the coupling 39, whereupon the toolholder 6a. falls and converts the work-piece 8 by percussive action into the final form.

In the construction according to Fig. 9, the rod-foot 20 and the tool-holder 60.- holding the upper tool I are each' separately guided on the pillars 42 of the press. The lower tool 2 is raised and surrounded by a rest 45 which supports the edge of the work-piece 8 and which can follow the movements of the recessed upper tool 1 by means of the pressure medium cylinders 44. 39a denotes the coupling which is illustrated only diagrammatically. by

The construction illustrated in Fig. 10has a lower tool 10 adjustable in height by pressure. medium cylinders 44.

In these types of construction, the rod 4, the hold-down 40, the rest 45 and the lower tool 2, instead of being moved hydraulically'or pneumatically may be moved mechanically, for instance, by a crank, double-lever, eccentric, togglelever and spindle, which is driven mechanically or by hand. Also, any desired combination of hydraulic, pneumatic and mechanical drives may be employed. a

In the various types of construction, the control device of the coupling arrangement, in' the case of an automatic arrangement, may be operatively connected to the tool-holder 6a, the holddown 40, the rest 45 or the lower tool 2 .in such a manner that, on application of the hold-down or the upper tool to the lower tool-or rest, a releasing device of the coupling is-brought into such a position that this releasing device comes into action on the ascent of the rod 4 after reaching a certain position and releases the coupling.

Figs. 11-14 show the application of the invention to presses with mechanically-driven pressing rods. v

In the press according to Fig. 11, two rods 4 are driven by eccentrics 46 of a shaft 41. According to Fig. 12, cranks 48 serve for driving the rods 4. According to Fig. 13, the rod 4 is connected to the spindle 49 of a friction-screw press. Fig. 14

' shows driving of the rod 4 by the toggle-lever 50 of a toggle-lever press- In each case, the toolholder 6a is slidably arranged in the press frame on guides 5| and is connected to the rod or rods 4 through a suitable controllable coupling device 39, 390; so that it can be decoupled. The mode of operation of these presses, which may also be driven by hand, is the same as hereinbefore described.

The invention can be used in drawing wide (i. e., stretched) sheet-metal parts and in hot and cold working.

'The operations of the press, consisting of pressing and striking or percussion, may take place in alternating sequence.

We claim:

1. A press of the character described, comprising asupport, a lower die, a rod movable vertically above said support, fluid-pressure actuated means for raising and lowering said rod, and for applying downward pressure thereto when lowered, a heavy tool-holder for holding an upper die, means releasably coupling said tool-holder to said rod so that it may be raised and lowered therewith, and fluid-pressure .actuated control means for releasing the coupling between said rod and said tool-holder whereby said toolholder will drop freely, independently of said rod.

2. A press of the character described, comprising a support, a lower die, a rod movable vertically above said support, fluid-pressure actuated means for raising and lowering said rod, and

therein for raising and lowering said rod, andfor applying downward pressure thereto when lowered, a heavy tool-holder for holding an upper die, a bayonet-joint coupling securing it to said rod so that it may be raised and lowered therewith, control means for supplying pressurefiuid to either end of the cylinder for raising and lowering the piston and means for rotating said rod to disengage the bayonet joint whereby said tool-holder will drop freely.

4. A .press of the character described, comprising a support, a lower die, a piston rod movable vertically above said support, fluid-pressure actuated means comprising a cylinder and a piston thereinfor raising and lowering said rod, and for applying downward pressure thereto when lowered, a heavy tool-holder for holding an upper die, a bayonet-joint coupling securing it to said rod so that it may be raised and lowered therewith, control means for supplying pressurefluid to either end of the cylinder for raising and lowering the piston and means comprising a worm wheel'carried by the rod and an electric motor having a worm, cooperating with said wheel, for rotating said rod to disengage the bayonet joint whereby-said tool-holder will drop freely. I

5. A press of the character described, comprising a support, a lower die, a piston rod movable vertically above said support, fluid-pressure actuated means comprising a cylinder and a piston therein for raising and lowering said rod,

and for applying downward pressure thereto when lowered, a heavy tool-holder for holding an upper die, a bayonet-joint coupling securing it to said rod so that it may be raised and lowered therewith,control means for supplying pressure-fluid to either end of the cylinder for raising and lowering the pistonJ means comprising a worm wheel carried by the rod and an electric motor having a worm, cooperating with. said wheel, for rotating said rod to disengage the bayonet joint whereby said tool-holder will drop freely, and cooperating electric contacts carried 15 by the respective members of the coupling, for controlling the said motor automatically.

6. A press of the character described, comprising a support, a lower die, a piston rod movable vertically above said support, fluid-pressure actuated means comprising a cylinder and a piston '7. A press of the character described, compris-- ing a support, a lower die, a piston rod movable vertically above said support, fluid-pressure actuated means comprising a cylinder and a piston therein for raising and lowering said rod, and for applying downward pressure thereto when lowered, a heavy tool-holder for holding an upper die, a releasable coupling securing it to said rod (4 so that it may be raised and lowered therewith,

said coupling comprising a slot in the tool-holder and movable bolts engageablei in said slot, control means for supplying pressure fluid to either end of the cylinder for raising and lowering the piston and means comprising fluid-pressure actuated mechanism for controlling said bolts to'enter or leave the slot at will, and thus to operate the said coupling.

8. A press of the character described, comprising a support, a lower die, a piston rod movable vertically above said support, fluid-pressure actuated means comprising a cylinder and a piston therein for raising and lowering said rod, and for applying downward pressure thereto when lowered, a heavy tool-holder for holding an upper die, a releasable coupling securing it to said rod so that it may be raised and lowered therewith, said coupling comprising an under-cut head on the tool-holder and movable bolts engageable under the said head, control means for supplying pressure-fluid to either end of the cylinder for raising and lowering the piston and electromagnetic means for controlling said bolts to engage or disengage the said head at will, and thus to operate the said coupling.

9. A machine for deforming sheet material by first pressing it partially into shape and thereafter applying a percussive blow thereto to complete the shaping of the material, which comprises a support, a lower die mounted thereon, a rod movable vertically above said support, a

.heavy tool-holder for holding an upper die, coupling means releasably connecting said toolholder to said rod so that it may be raised and lowered therewith, fluid-pressure actuated means for raising and lowering said rod, to press the material partially into shape, and control means for actuating the said coupling means to release said tool-holder, whereby it will drop freely and apply a percussive blow to the material.

LUDWIG OECKL. ERHARD MI'J'IILER.

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