DE1257539B - Device for pressing hollow parts - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

B 21k

German class: 49i-16

Number: 1257539

File number: G 407381 b / 49 i

Filing date: June 2, 1964

Open date: December 28, 1967

Devices and machines for pressing hollow parts are known per se. However, they are so far Only suitable for metals with a low forging resistance and a low one Have forging temperature. Both the mechanical and the thermal load capacity of the known Facilities is namely low.

Most facilities work with an overall mobile tool set. Upper and lower die perform a joint evasive movement after closing. This movement is going through Transfer suitable levers to the mandrel slide. Due to the multitude of movements, namely the Upper to lower die, the two closed dies together with the tool holder, the lever and the mandrel slide, a very unstable device is created which, if they Forging steel subjected to required forces and speeds would either break or at least it would wear out quickly. The masses involved in the movement leave one higher speed, which is absolutely necessary to reduce the thermal stress, not to.

In another device, the lower die is fixed and there is a relative movement between Upper die and upper die carrier used to achieve the mandrel slide movement. That However, the upper die is not safely guided, but only suspended from jacks and joints, and the return springs act on the actuating levers of the mandrel slides. This facility is true suitable for non-ferrous metals at higher temperatures and higher forging resistance, such as steel requires, however, difficulties arise. If the mandrels are not thermal under these conditions are to be overstrained, the contact time with the workpiece may only be short, i. H., the mandrel slides must be moved at significantly higher speeds. Because the transmission lever apart from guiding the upper die and overcoming the resistance of the mandrel slide must also be dimensioned for the additional, considerable spring resistance and the Construction uses three levers, rapid movements lead to impermissible inertia forces and rapid die wear. The device is therefore also unsuitable for hollow forging steel.

The present invention avoids the disadvantages outlined by using a stable, central piston, which is in an equally stable device for pressing hollow parts

Applicant:
Dr.-Ing. Otto Georg,
Breckerfeld-Branten, Oststr. 12th

Named as inventor:

Dr.-Ing. Otto Georg, Breckerfeld-Branten

Cylinder is ideally guided and in turn allows the attachment of strong abutments. The spring is immediate arranged behind the upper die support, so that the lever only applies pressure to the Have to transfer mandrel slide. All masses are reduced to a minimum and solidly managed, like that that the required, sudden increase in speed and forging pressure to the Mandrel slide is guaranteed. So the facility is that which occurs when forging steel can cope with high forces and reduces the contact time and thus the thermal stress of tools.

Other advantages are not neglected either. The closing pressure of the split in the mandrel level Die is reinforced by the working pressure of the mandrel, so the harder the mandrel press, the more The closing pressure increases so that the dies cannot gap. the Burr formation and the wear of the ridge path caused by the burr are therefore kept to a minimum scaled down.

It is also possible to use particularly strong springs in the spacious cylinder, which are not necessarily disc springs must be installed, so that a safe retraction of the mandrel slide is guaranteed. You can all the more so because they do not place additional demands on the transmission levers.

The figures show an embodiment of the inventive concept.

Fig. 1 shows half of a longitudinal section at the bottom dead center of the press ram,

Fig. 2 a longitudinal section in its uppermost position,

Fig. 3 shows a cross section in the plane of the mandrel.

The sections Fig. 1 and 2 are one of the diagonal plane of A b b. 3 led. On the press ram 1 a cylinder 2 is attached, in which a piston 3 is

709 710/132

Claims (3)

can move axially. It is pretensioned by disc springs 4. Angle levers 5, which are pivotably mounted in corresponding grooves in cylinder 2, engage in piston 3, four in the example. The lower ends of the angle levers are provided with rollers 6 which each engage in a corresponding recess in the mandrel slide 7 as soon as the ram of the press has finished its idle stroke. The mandrel slides 7 are mounted to be longitudinally displaceable in a cross guide 8 which is fastened to the press table 9. The lower tool 10 is fastened to the cross guide frame, the upper tool 11 to the piston 3. Instead of the rollers, push rods 12 can also be articulated on the angle levers S, which engage with the second bearing on the mandrel slide 7, which then have to be made correspondingly longer. This variant is in A b b. 2 indicated by dash-dotted lines. The operation of the device is now as follows: The forging blank is opened with the die, i. H. inserted in the uppermost position of the press ram 1 and the machine started. During the downward movement of the press ram, the dies 10 and 11 first meet and complete the engraving. The rollers 6 have already entered the recesses in the mandrel slides 7. The piston 3 now gives way against the pressure of the disc springs 4. The mandrel slides 7 are pressed towards the center via the angle lever 5. They penetrate the blank and cause it to fill the engraving. The increasing pressure of the mandrels acts via the angle lever 5 to increase the pressure between the two die halves (10 and 11), so that there is no gaping. If the press ram goes up again, the plate springs 4 press the angle levers 5 down and the mandrel slides 7 are moved outward. Before the rollers 6 emerge from the recesses of the mandrel slides, they have reached their rear dead center position again. After the springs 4 have relaxed, the ram moves even further upwards in order to create space for insertion between the die halves 10 and 11. The ejector 13, which is actuated by the press ram, can eject the workpiece. The device is now ready for the next workpiece. The working example is applied to a cross piece that has four ends. In the case of T-pieces, one side of the device can be shut down, and several workpieces that only need one mandrel can be pressed with one ram stroke. The device is easy to install in any normal press. It is robust and extremely reliable. Because of the low mass of the masses participating in the movement, the mandrel slides can be moved so quickly that the mandrels themselves are least stressed and can therefore be used with advantage for hollow forging iron. At most, they can still be cooled from the inside or outside. Patent claims: 1. Device for pressing hollow parts, in which the main pressing movement is a transverse pressing movement is derived after the die closure, wherein the upper die is arranged displaceably with respect to the upper die carrier and the transverse ram during this relative movement via a pivotable lever system actuated and a return of the transverse press ram with disc spring relaxation, characterized in that the upper die carrier (1) as a known piston-cylinder unit (2, 3) with an enclosed disc spring assembly (4) is formed and that on the cylinder (2) mounted angle lever (5), on the one hand engage in grooves in the piston (3) and, on the other hand, in recesses in the cross-compression slide (7), are provided. 2. Apparatus according to claim 1, characterized in that the angle lever (5) by means of Engage the rollers (6) on the cross press slide (7). 3. Apparatus according to claim 1, characterized in that the angle lever (5) by means of Engage the push rods (12) on the cross press slide (7). Considered publications:
German Patent No. 147,939;
German Auslegeschriften Nos. 1148 846, 1111482; French patent specification No. 1308 955. 1 sheet of drawings 709 710/132 12.67 © Bundesdruckerei Berlin