US 3120304 A
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Feb- 4, 1964 HANS-JoAcHlM PAHNKE ETAL 3,120,304
EXTRUSION PRESSES Filed Deo. 22. 1960 United States Patent O 3,12%,364 EXTRUSN ll? SSES Hansdoaehim Pahnlre, Eusseidor-lath, Germany, and
Pierre Roux, laris, France, assigner-s to Maschinenfabrik Sack GnnJhEl., and Etablissements L. Morane Filed Dec. 22, 195%, Ser. No. 77,662 Claims priority, application Germany Dec. 24, 1959 2 Claims. (Cl. 207-4) One common type of extrusion press includes a dieholder and a container which receives the material to be pressed and which is mounted adjacent to the die-holder. The material is extruded from the container at high pressure by a ram through the die to form the extruded article. When most of the material has been extruded, the extruded material is severed outside the die and the press is prepared for another operation.
Previous presses of this type have not been very profitable to operate because considerable time is required for the ancillary operations, such as removing the residue of the material, cooling, cleaning and lubricating the die and recharging the container, so that the press has a very low ratio of useful time to dead time. This ratio is particularly low where steel and other substances which are or" relatively low material value are being pressed, since the total costs or the pressed product are mainly determined by the press operating time and by labor costs.
Attempts have been made to increase the eiciency of extrusion presses by using a number of containers arranged to be introduced into the press in turn. With this arrangement, a number of containers are introduced into a holder which can be moved transversely of the press axis, or into a holder which can be pivoted around a part of the press frame, the holder moving the containers alternately into the position for pressing and into the loading p sition. However, even these improved extrusion presses have disadvantages which prevent the simultaneous performance of a number or" working steps; for example they do not provide a satisfactory solution of the problem of removing what remains of the material after pressing while the press is in operation. Also, displaceable holders for two containers have the particular disadvantage that new blocks for pressing must be introduced on different sides of the press alternately.
In order to provide full utilization of the extrusion press according to the present invention, three containers are attached to a pivoted spider, and three dieholders re releasably secured, one to each of the containers; so that when the spider is rotated, the containers move between the ram and two auxiliary devices which can be operated independently of the ram and of one another but simultaneously with the ram, the first such auxiliary device incl ding means for ejecting from the container the residue left in the container after the pressing operation, a pressing plate and the dieholder, and the second auxiliary device including means for introducing into the container new material for pressing and a pressing plate and means on the opposite side of the container for introducing a dieholder and die.
Since extrusion presses operate at fairly high temperatures, they are subject to considerable and disturbing heat expansion effects which may easily lead to the central axis of the press ira-me going out of alignment with the axes of the pivoting containers. lt is also important to lreep away from the press the considerable forces which are applied to the containers in the auxiliary devices, in order not to disturb the pressing operation which is performed simultaneously with the auxiliary jobs. It is preferable, therefore, for the containers to be disposed on a pivoting spider with radial clearance, and means are provided to center whichever container has been pivoted into the operative position in line with the press axis.
Such means may be arranged to press the container against the die support member, and may comprise centering surfaces which co-operate with conical annular surfaces or cylindrical centering projections on the containers and which help to align them with the press axis when the container is pressed against the die support. This method of centering the container relatively to the ram is very advantageous when tubes and similar hollow articles are being pressed where uniform wall thickness is important.
The maximum prolitability of such a press is obtained by using three containers which are arranged to be moved along a circular path into the press in sequence. If fewer containers are used, waiting times between the various pressing operations are increased, since the steps of ejecting the residue of the bloclr lett after pressing and of recharging one and the same container must succeed one another in time; on the other hand, if more than three containers and a correspondingly greater number of auxiliary devices are provided, the outlay on equipment is increased and it may occasionally become ditlicult to work on the press but no appreciable time is saved.
Preferably, the first auxiliary device comprises a press having a driven ram and a support member against which the container bears so that it is freed of residue, the support member being formed with an aperture through which such residue, the dieholder which is ejected with it and the die can pass. The second device may comprise the use of two rams which can be moved in opposite directions to one another and relatively to the container which is pivoted into a position between the rams, one such ram introducing a new block and a pressing plate into the container while the second such ram introduces a dieholder and die into the container from the opposite side.
In order that a container may be changed immediately upon the completion of a pressing operation, a saw arranged to be pivoted in a plane perpendicular to the pressing direction may be iixed to the press and is arranged to cut the extruded article from the residue immediately after the die has been disengaged together with the container from the die support.
One example or" an extrusion press in accordance with the present invention is diagrammatically illustrated in the accompanying drawings in which:
FlGURE l is a longitudinal sectional view of the press;
FGURE 2 illustrates an auxiliary device;
FIGURE 3 is an end elevation of the press.
The press comprises three containers 1 3 disposed on a pivoting spindle 4 rotatable around a member of the press trarne. As can be seen in FIGURE 3, the containers 1 3 are retained in the spider 4 with radial clearance. A dieholder 6 and its die 6a are releasably connected to each container. Whichever container has been pivoted inwards into the center of the press is pressed against a die support member 8 by a crossbeam 7 which is arranged to be moved independently of the press drive. The crossbeam 7 and the containers 1-3 have conical locating surfaces ensuring that whichever container has been pivoted inwards into the press is aligned accurately with the axis thereof when the container is pressed against the member S by the descending crossbeam 7. The spider 4 can be moved by a hydraulic drive l1 to lift the containers otl the member S. A saw 9 is pivotally mounted on the p *ess frame member, and, after the container has been lifted oil the member 8 by the drive 11, is arranged to cut the extruded material which has issued from the dieholder. The charging device comprises two rams l5, le which can be driven in opposite directions 3 to one another; the ram serves to introduce a block 5 and a pressing plate into the pivoted-out container 3, while the ram 16 introduces a dieholder 6 and die 6a into i the same container but from the opposite side thereof.
The auxiliary device illustrated in FIGURE -2 takes the form of a press which comprises a support member for the containers from which the pressing residue 12 is to be removed, and a driven pressing ram 14 which ejects the residue 12, pressing plate, dieholder and die through an aperture in the support member for the container. The auxiliary devices can be operated independently of the press or simultaneously with it.
The press operates as follows:
As shown in the initial position of FlGURE 1, after a block of material placed in the container 1V has been extruded to form an extruded member, the spider 4 and containers 1-3 are moved axially by means of the drive 11. After the dieholder 6 is moved into the centre of thev press, the saw 9 is pivoted and cuts the extrusion from the residue left in the container after pressing. The spider 4 is then pivoted clockwise through an angle of 120 so that the container 1 moves into the auxiliary press shown in FIGURE 2, while the container 2, which has previously had the residue 12 removed from it in the auxiliary press, moves into the charging device (without a dieholder, since the previously used dieholder was ejected together with the residue 12) shown on the right-hand side of FIGURE l. While a container which has previously been ypro 'ided in the charging device with a new block has moved into the position for pressing, a block is extruded in the press, a new block and a new dieholder rand die are introduced into a container in the charging device, while in the auxiliary device shown in FIGURE 2 the residue 12, dieholder 6 and die 5a are ejected from the container which has just come from the main press.
The residue 12 is separated from the pressing plate, die and dieholder outside the auxiliary device. The time required for this step does not affect the operation of the press and auxiliary devices if an adequate number of pressing plates, dieholders and diesr are available.
1. A tube andistrand extrusion press, comprising ak press-frame member, a star-shaped carrier pivotablyV mounted on said member and having at least three die containers attached thereto for rotation therewith about the axis of said carrier between an extrusion pressing position and a charging position in a series of switching steps, a pressing plunger disposed at said pressing posi* tion and movable in a direction parallel to said axis for extruding a block of material through a die in a respective one of said containers located at said pressing position, a plurality of die holders removably connected with respective ones of said block containers and thus jointly t a corresponding Ydie holder, said ejector plunger beingV movable into said container for loosening said corresponding die holder and its die from said container, and support means on said ejector press for supporting said container during operation of said ejector plunger, said support means having an opening therein for passage therethrough of said die holder and residue, and a second auxiliary device comprising a block inserting ram disposed at a location corresponding to said charging position and movable in a direction parallel to said pressing plunger and relative to a corresponding die container at said charging position for introducing into one side of the latter a new block of material for pressing and a pressing disc, said second auxiliary device having a push-inV tappet arranged coaxially relative to said block inserting ram and facing theopposite side of the container at saidV charging position relative to said inserting ram, said tappet being movable in a direction Vopposite to said block inserting ram and at the same time as the latter for inserting a die holder and die into said opposite side of said container at said charging position.
2. A press according to claim 1, said containers being mounted on said carrier with radial clearance Vsutlicient to avoid mutual interference, said containers each being provided at one end with a centering surface, a crossbeam on said press provided with a surface at said pressing location and mateable with said centering surface on a corresponding contaier for centering the latter, and a support on said press kfor supporting said container at said press position on its end opposite said centering surface.
References Cited in the le of this patent UNITED STATES PATENTS 2,337,804 Dempsey Dec. 28, 1943 2,880,867 Keck Apr. 7, 1959 FOREIGN PATENTS 1,163,770 France Apr. 28, 1958