US2129774A - Draw press - Google Patents

Description

2 Sheets-Sheet l O. KUHNER DRAW PRESS Filed May 20, 1936 Sept. 13, 1938.

Sept. 13, 1938. o. KUHNER DRAW PRESS Filed May 20, 1936 2 Sheets-Sheet 2 HTT'OQIVEY Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to improvements in hydraulic draw presses which are used for the production of hollow bodies from sheet metal plates.

In such presses the plates or sheets are clamped over a table adapted to be moved hydraulically. On the table is secured the pattern, for example a wooden pattern necessary for the production of the hollow body. By movement of the table against the clamped metal sheet the pattern is forced into it.

With patterns which do not have a simple form but show, for example, a plurality of curves or any other unusual form, it is not possible to clamp the sheet so that it bears throughout on the pattern. The drawing process does not then begin uniformly over the whole pattern. During the process the portions at which greater stretching occurs conform to the pattern more strongly and sharply than the portions subjected to lesser stretching. Moreover, these differences have to be equalized and it is necessary first to work the portions of lesser stretching, for example the fiat portions, and then, by adjustment of the form, the portions subjected to greater clamping. Formerly this was efiected by the interposing of liners between the table and the pattern, this necessitating a very correct working of the liners.

' The invention consists essentially in that the table is arranged movable in space and fixable and that the clamping device consists of blocks mutually adjustable individually or in groups, which blockscare arranged either on opposite sides only or on all sides of the table. With such the table without special liners being necessary. In this way the use of such presses is simplified and the possibility of their use extended.

Moreover, the construction of the clamping device accord ng to the invention serves to overcome the difficulties which arise during drawing with complicated patterns. For example, the new construction of clamping device enables desired form of curve. Re-clamping, that is to say a second working process, or patterns with exchangeable parts are no longer necessary.

.The constructional form of the clamping device and the table according to the invention may be as desired, but the following more fully described forms are particularly advantageous. Each section or block of the clamping device is secured by one or more bolts to the base plate, which is likewise adjustable in a known mana construction of press the pattern can be brought to any desired position by adjustment of clamping of the sheet to be obtained along any ner. The bolts are guided in slots in the blocks, which themselves lie on the base plate either adjustable in plane surfaces or swingable in' cylindrical surfaces.

The adjustability of the table is attained in a simple way by supporting it at at least three points and connecting the table by ball and socket joint with a hydraulically operated ram. The table can, however, also be moved by carrying it on two or more independently'operating hydraulic pistons. Thus, if the centres of the pistons lie in one plane, a swinging movement about parallel axes is possible. With other arrangements of the piston centres, the table can be adjusted still further. The table can be adjusted in any desired direction, if it is adjustably supported at at least three points, and a ram carried by two or more pistons serves as the supporting device. This arrangement offers a possibility f double adjustment for firstly the ram can be adjusted as desired and on the other hand the table, which is supported against the ram, is adjustable in any direction relatively to the latter.

Some embodiments of the invention are lustrated in the accompanying drawings by way f example, in which:

Fig. 1.is an elevation of a draw press.

Fig. 2 is a plan view thereof.

Fig. 3 is a side elevation of Fi 1.

Fig.4 is a part sectional elevation of a modified form of table. a

' Figs. 5 and 6 are an elevation and plan view respectively of a clamping device in accordance with the invention, and

Fig. '7 is an elevation of a modified form of clamping device.

In the draw press according to Figs. 1.3, two base plates 2 and 3 rest on three supports I. The base plates 2 and 3 are relatively adjustable and fixable in the direction of the transverse axis of a plate 4 and carry along their sides the clamping blocks 5 and 6, which, shown diagrammatically only in Fig. 2. are adjustable on the base plates 2 and 3 in' grooves I and B respectively; The plate 4 is carried by a piston 9 which reciprocates in a cylinder l0 under the action of water pressure in known manner. The plate 4 is, moreover, formed with a ball seat in which a ball I I rests. The latter is secured to the actual press table [2 on which the pattern l3 rests. The table l2, moreover, is supported against the plate 4 by three adjustable bolts I 4. In Fig. 1 the press is illustrated, with the table [2 not adjusted, at the end of a working stroke, the stretched workpiece l5 being omitted. The latter is shown in the clamping blocks 6 have been omitted. At

the commencement of the working operation the metal sheet is clamped in the bloclns 5, whereupon the piston 9, plate 4, table 12 and pattern l3 are forced upwardly against the workpiece I5, which takes the form of the pattern I3. In Fig. 2 the blocks 5 are relatively displaced and likewise the blocks 6 can take a difierent relative position. The arrangement of these blocks 6 enables the workpiece to be clamped not only at opposite sides but on all sides, or to be held only by means of the blocks 6 without, as was formerly necessary, the table l2 having to be turned through 90 and the base plates 2 and 3 separated from one another.

The draw press according to Fig. 4 employs the same clamping devices asthat according to Figs. 1 to 3, but the table I6 is adjustable in a different manner. The said table is pivotally mounted on three bearings l1, l8 and IS, the bearing l8 being connected to a slide block 20, which is guided in the straight guide 2| carried by supports 22. On the latter and also on supports 23 rest cylinders 24 in which pistons 25 slide under the action of water pressure, the said pistons carrying dovetail-like bearings 26 in which slide members 21 carrying the bearings l1 and IS. The piston 25 is or both pistons are lifted for adjusting the table I6. During the actual drawing operation the table is pressed against the clamped sheet blank by further raising of one or both pistons. Also in this case a pattern, not shown in Fig. 4, is secured to the table IS.

The two embodiments of the clamping device shown in Figs. 5-7 can be used in the presses according to Figs. 1-3 and 4. The clamping device according to Figs. 5 and 6 rests on the base plate and is moved thereon for the purposes of adjustment, whilst the clamping device according to Fig. 7 is guided, that is to say is swingable in a cylindrical surface.

The arrangements according to Figs. 5 and 6 consist of a block 28 on which are arranged two eyes 29 having slots 30 therein in which are guided the bolts 3| for securing the block 28. The edge of the sheet to be treated is clamped between a swingable plate 32 and a projection 33 of the block 28. The pivot pins 34 of the plate 32 rest in plates 35. The plate 32 is adjustable by means of a lever 36 fixed to the plate 32 and movable in a slot 31 of the block 28. Raising the lever opens the clamping device and depressing closes it. This arrangement can also be secured in a simplified construction with only one bolt 3|.

The clamping device shown in Fig. 7 besides being adjustable on the base plate 38 is swingable in the cylindrical surface 39. The under part 40 is held against the base plate 38 by a bolt 4|, whilst the upper part 42 is held by a bolt 45 swingable at 43 in the under part 40 and carried in the upper part 42 by a ball joint 44. The actual clamping device, viz. projection 46 and plate 41 are formed the same as in the arrangement according to Figs. 5 and 6.

I claim:

1. In a hydraulic draw press of thetype referred to, the sub-combination of t a base; a ress table movable relatively to said base; means for tilting said press table and clamping devices for a sheet to be treated, said devices comprising a plurality of blocks secured to said base, said blocks each comprising an under part having an upper concave surface, and an upper part having a convex surface movable over said concave surface; and means for holding said upper part in engagement with said under part.

2. In a hydraulic drawpress of the type referred to, the sub-combination of: a base; a press table movable relatively to said base; means for tilting said press table, said means comprising means for adjustably supporting saidtable at at least three points; and clamping devices for a sheet to be treated, disposed around said table on said base.

3. In a hydraulic draw press of the type referred to, the sub-combination of a base; clamping devices on said base; a press table; means for tilting said press table, said means comprising adjustable supports for said table; a ball carried by said table; a second table supporting said press table by means of said supports and said ball; and means for operating said second table.

4 In a hydraulic draw press of the type referred to, the sub-combination of a base; a press table; means for tilting said press table, said means comprising a cylinder carried by said base adjacent each end of said table and a piston movable in each of said cylinders for moving said table.

5. In a hydraulic draw press of the type referred to, the combination of: abase; a press table; means for tilting said table, said means comprising adjustable supports for said table, a ball carried by said table, a cylinder; and a piston in said cylinder, said piston having a bearing surface adapted to support said ball; hydraulic means for actuating said piston to move said table; a

clamping devices for a sheet to be treated, said devices comprising a plurality of blocks secured to said base, said blocks each comprising an under part having an upper concave surface, and an upper part having a convex surface movable over said concave surface; and means for holding said upper part in engagement with said under part.

6. In a hydraulic draw press of the type referred to, the combination of: a base; a press table; means for tilting said table, said means comprising adjustable supports for said table: a ball carried by said table, a cylinder, a piston in said cylinder, said piston having a bearing surface adapted to support said ball; and hydraulic means for actuating said piston to tiltsaid table; and clamping devices for a sheet to be treated disposed around said table.

7. In a hydraulic draw press of the type referred to, the sub-combination of: a base; a press table movable relatively to said base; means for tilting said press table; and a plurality of clamping devices for a sheet to be treated upon said base, disposed on each side of said table, each of said clamp devices being adjustable and securable independently of each other of said devices, whereby said sheet may be clamped on opposite sides or on all sides of said table.

8. In a hydraulic draw press of the type re ferred to, the sub-combination of a base; a press table; a centrally disposed pivot bearing for said table; means for tilting said press table, said means comprising a cylinder carried by said base adjacent each end of said table and a piston movable in each of said cylinders to tilt said table.

9. In a hydraulic press of the type referred to, the sub-combination of a base; a press table; a centrally disposed pivot bearing for said table; and means for tilting said press table, said means comprising a cylinder carried by said base adjacent each end of'said table, apiston movable said pistons independently of one another to tilt the said tableas required. I

10. In a hydraulic press for the production of hollow bodies from sheet metal plates, the subcombination of: a base; a press table disposed above said base; and said table being movable relatively to said base; a pattern necessary for the production 0!. the hoilombody carried on the upper face of said table remote from said base and over which a sheet to be treated is stretched; clamping devices for said sheet disposed around said table on said base; and means for tilting said 5 press table and pattern.

A o'rro KtiHNER.

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