US2245723A

US2245723A - Stretching press

Info

Publication number: US2245723A
Application number: US265428A
Authority: US
Inventors: Salzmann Josef
Original assignee: Henschel Flugzeugwerke AG
Current assignee: Henschel Flugzeugwerke AG
Priority date: 1938-04-07
Filing date: 1939-04-01
Publication date: 1941-06-17
Anticipated expiration: 1958-06-17

Description

June 17, 1941.

J. SALZMANN STRETGHING PRESS Filed April l, 1939 3 Sheets-Shea?I 1 4 Inventor.'

AfrlllNly nel' `fune 17, 1941.

J. sALzMANN STRETCHING PRESS Filed April l, 1939 3 Sheets-Sheet 2 June 17, 1941. J. sALzMANN 2,245,723

STRETCHING PRESS Filed April l, 1939 3 Sheets-Sheet` 3 /n venor @luf/x. S4( @Mv KWS. i

IIIIIII gr gite- 1. .russia-.1941

STRETCHING PRESS Josef Salzmann, Munich, Germany, assignor to Henschel Flugzeug-Werke A. G., Schoenefeld,

Kreis Teltow, Germany Application April l, 1939, Serial No. 265,428

In Germany April'7, 1938 7 Claims.

'Ihe present invention relates to a stretching press with which a sheet metal clamped in opposed vises may be shaped by a die secured to a die-table. In machines of the type under consideration the shaping operation is carried through by raising the table and die with the aid of plungers actuated by a pressure means and thus pressing the die against the surface of the sheet metal held by the vises in operative position. During the shaping operation it occurs frequently that the stresses created in the sheet metal by the tensile forces acting in the direc.- tion of the opposite vises fail to cause certain individual portions of the sheet metal to follow the contours of the die. If such portions are small, they are usually worked with hand hammers-during the stretching operation. If, however, such portions are larger the sheet metal is reclamped in another position and thus stretched in the pertainingdirection. Stretching presses are already known in the art, which are equipped with a square die table and with vises for the sheet metal, opposite the four sides of the table for the purpose of clamping the sheet metal on all sides or of using either the one or the other pair of opposite vises.

The present invention aims to improve a die press of the said type so as to simplifyand to reduce the cost of the operations of stretching the job in two directions at r..ght angles to each other. A further object of the invention is to make the die press useful for the production of elongated as well as of deep forms.

'Ihe invention mainly comprises a stretching machine with a die table which is rotatable about a vertical axis .and adjustable in various positions for operation between two opposite vises. The invention further consists of vises adjustable to an extent corresponding to the difference of the diametral dimensions of the die table surface.

According to the invention the stretching press is preferably so designed that the die table is pivoted with a central journal about a vertical axis and shiftable in the direction of such axis, a plurality of plungers being diametrically arranged on a circle, and the plunger heads being adapted to serve as supports of the die table.

Further details and objects of the invention will be apparent from the description hereinafter and the accompanying drawings showing an embodiment of the invention by way of example.

In the drawings:

Fig. l is a top plan view of a device according to the invention Fig. 2 is aside elevation of the device ofFig. 1 gartially a sectional view along 'the line II-II of Fig. 3 is a side elevation similar to that of Fig. 2 the die table being turned Fig. 4 is a top view corresponding to Fig. 3;

Fig. 5 is a transverse sectional. view along the line V-V of Fig. 3 in an enlarged scale, the pressing plungers being in their lowermost inoperative position to facilitate the turning of the die table;

Fig. 6 is a top view of the device shown in the preceding figures, the die table being replacedby another-of a modified form.

Referring now to the drawings, there is a frame comprising two spaced longitudinal members I connected tov each other by end members 2 and a cross-member 3. A central bearing 4 with vertical axis is provided in that cross member for a king-pin-like journal,5 of a die table 6, which thus, is rotatable about said vertical bearing axis. The die table is adapted to receive thereon a die l, which may be secured to the table by any suitable means, such as indicated at 32. Laterally of said die table and opposite to each other two vises or groups of vise devices 8 and 9 are arranged on said longitudinalmembers so as to be movable thereon towards and away from said die table. .Each of the vises 8 and 9 is provided with a lower projectiony I0 and II respectively serving as a means of connection for a drive to shift the vises in the said directions. In the illustrated embodiment, such drives comprise spindles I2 and I3 respectively engaging interior threads I4 and I5 ofthe pertaining projections I0 and II. The spindles I2 and I3 are supported in bearings' I6 and II respectively provided in the end members 2 and in the cross member 3. In order to rotate the spindles and to shift thereby the vises, the spindles maybe connected to electric motors I 8 and I9 respectively. The vises may be provided with clamp plates 20 and'screw bolts 2l to secure them in an adjusted position. On a circle 22 about the axis ofthe king-pin 5 pairs of lifting devices such as plungers are so arranged that the individual plungers of a pair are diametrically opposite each other. In the illustrated embodiment', twopairs 23 and 24 of plungers are provided.

l However, any desired number of pairs may be used. Each plunger device is connected to av pipe line indicated at 25 for admitting and discharging a pressure means whereby a plunger may be raised and lowered. The plungers have heads 2G and 21 respectively, adapted to bear from below against supporting surfaces 28 of the die table 6.

Suitable means may be provided for rotating the die'table 6. Such means may comprise a worm drive 29, which may be connected to an actuating means such as electric motor 30. Worm 29 engages a gear wheel 3l which is secured to king-pin so as to be capable of rotating the latter without interfering with an axial movement of the kingpin relatively to wheel 3|.

Now, in order to produce elongated forms, first all

plungers

23 and 24 are lowered to their lowermost position. Shortly before those plungers, which are just carrying the die table, reach that position, the lower center surface 33 of the die table abuts against the top surface of bearing 4 so that the die table is borne by the latter as shown in Fig. 5. Then, the die table may be adjusted to the position illustrated in Figs. 1 and 2 by actuation of the worm drive device 29, 30, 3i. Thereupon, the die 1 may be secured to the table 6 and a metal sheet 36 spread over the die. By turning the spindles I2 and I3, the vises may be brought into correct position so as to receive and clamp opposite edges 34 of the metal sheet. By tightening the screw bolts 2l', the vises will i be safely held in their adjusted position. 'I'hereafter, a pressure means may be admitted to pair of plungers 24. In rising, the heads 26 of plungers 24 will contact the surfaces 23 and then lift and press the die table with the die against the lower surface of the metal sheet, thereby stretching the latter and shaping it according to the form of the die. -In order now to perform stretching of the sheet metal 36 in a direction at right angles to the first stretching operation, the edges 34 of the sheet metal will be released from the vises, and the plungers 24 lowered until they have deposited the die table withsurface 33 on the top of bearing 4. Thereafter, the table may be turned 90 degrees in the ma'nner hereinbefore described, so as-to take the position illustrated in Figs. 3, 4 and 5. Then the vises will be shifted close to the table so as to grip the edges 35 of the sheet metal 36. After the edges 35V are secured to the vices, the plungers 23 may be actuated to cause the stretching of the sheet in a direction at right angles to the first stretching.

Thus the die press according to the present invention is useful to apply elongated and narrow dies to long jobs which are to be stretched in the longitudinal direction of the die, when the die table is positioned with its longitudinal extension between the vices. Or, dies for jobs of a deep form may be used which jobs are to be stretched transversely of the die when the table is turned 90 degrees off the first mentioned position, and the `vises are shifted close to the table. Furthermore, with jobs which' are to be stretched in different directions it is possible by turning the table, to reclamp the job without removing it from the die.

Fig. 6 shows a die table 4U which is a modification of that of Figs. 1 to 5. The die table 40 is of a substantially square shape and has a journal 4I `and alower ring-shaped supporting surface 42 adapted to be engaged by all

plungers

23 and 24. It is clear, that with a so shaped die table, the plungers may be actuated either'in pairs as described hereinbefore, or all at once. Furthermore the turning of the table and the reclamping of the job may take place without rst lowering the table to a position where it may be supported by a stationary abutment such as surface 33 in cooperation with bearing 4 of Figs. 1 to 5. In other respects the die press of Fig. 6 is similar to that shown in the preceding figures. The table design of Fig.'6 is particularly adapted to facilitate repeated reclamping and stretching in different directions.

Other suitable forms of the die table and of the arrangement of devices for lifting the same, and which are within the scope of my invention will be apparent to those skilled in the art.

What I claim, is:

1. A die press comprising in combination two opposite vises movable towards and away from each other in a horizontal path, a die table arranged between said vises and including a kingpin with vertical axis, a collar bearing for said king-pin, two pairs of diametrically opposite devices for lifting and lowering said die table, said devices being arranged on a circle about said vertical axis and one of said pairs on the circle diameter which coincides with the direction of the path of the vises, and the other one of said pairs on a diameter at right angles to that of the first mentioned pair, and means for adjusting said vises as to their distances from said vertical axis.

2. A die press comprising in combination two opposite vises movable towards and away from each other in a horizontal path, a die table arranged between saidvises and adapted to rotate through at least about a vertical axis, means for lifting and lowering said die table, an abutment for said die table to support it in its lowermost position, said abutment being so arranged and constructed as to permit rotation of said die table when bearing on said abutment, and means for adjusting said vises as to their distances from said vertical axis, said means for lifting and lowering said die table comprising two pairs of plungers arranged on a circle about said vertical axis, the plungers of one of said pairs being arranged on that diameter which coincides with the direction of the path of said vises, and the plungers of the other pair being arranged on a diameter at right anglesto the first mentioned diameter, said plun'gers including heads adapted to engage said die table from below, and having a lowest position in which said heads do not engage said die table when the latter is ih its lowermost position.

3. A die press comprising in combination two opposite vises movable towards and away from each other in a horizontal path, a die table including a lower center pin with vertical axis and being rotatable through not less than 90 about said vertical axis, a collar bearing for said pin, so arranged and constructed as to permit rotation and axial displacement of said pin with said table relatively to said bearing, a plurality of diametrically opposite plungers arranged on a circle about said vertical axis, each of said plungers including `a head adapted to support said die table, and a ring-shaped surface on the bottom side of the tablefor engagement with said plunger head.

4. A die press comprising in combination two opposite vises movable towards and away from each other in a horizontal path, a die tablearranged between said vises and rotatable through at least an angle of 90 about a vertical axis, and a plurality of pairs of devices for lifting and lowering said die table, the individuals of each pair being arranged diametrically opposite withfreL.;

antenas clding a king pin aiid heilig ariaiised between said vises and rotatable about the axis of said king pin through at least an angle of 90. splu- 'raiity of pairs of devices for lifting and lowering said die table, the individuals of each pair being arranged diametrically opposite with respect to said axis and being spaced to support the table in predetermined angular positions. and means in a driving connection with said king pin for rotating said die table.

6. A die press as claimed in claim 4 further comprising an abutment for said die table to support it in a lowermost position when said devices in lowering said table have deposited it on said abutment, said abutment being so constructed and arranged as to permit rotation of said die table when bearing on said abutment.

'7. A die press comprising in combination two opposite vises movable towards and away from of said pairs whereby lifting and lowering of .saidI die may be effected by either one of said pairs depending on the position of said die table with said supporting faces opposite the one or the other pair of said lifting and lowering devices, and means for adjusting said vises as to their distances from said vertical axis.

J OSEF SALZMANN.