Abstract:
A powder press in which seals of cylinder/piston units that can hydraulically activate or apply pressure to additional plates with reference to a die plate, the upper yoke and/or the lower yoke are kept free of powder to the greatest possible extent disposes a cylinder of a cylinder/piston unit facing away from a die plate and/or an additional plate, preferably below the additional plate.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of and Applicant claims priority under 35 U.S.C. §§120 of U.S. application Ser. No. 13/934,561 filed on Jul. 3, 2013, which claims priority under 35 U.S.C. §119 from German Patent Application No. 10 2012 013 229.8 filed on Jul. 4, 2012, the disclosures of each of which are hereby incorporated by reference. A certified copy of priority German Patent Application No. 10 2012 013 229.8 is contained in parent U.S. application Ser. No. 13/934,561. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a powder press having an upper yoke, a lower yoke, and tension elements that are in effect between the upper yoke and the lower yoke, as well as having a die plate that is guided parallel to the tension elements, and having at least one additional plate, preferably configured as a lower plate, which is also guided parallel to the tension elements, which plate can be hydraulically activated, with reference to the die plate, the upper yoke and/or the lower yoke, or to which plate pressure can be applied, via a cylinder/piston unit. 
     2. Description of the Related Art 
     Powder presses of a different type are known, for example, from DE 10 2005 027 296 B3, whereby here, ultimately multiple die plates are guided parallel to one another and additional plates, particularly lower plates, are not disclosed. Arrangements of the same type are known, however, for example from the still unpublished document PCT/DE2011/002187, whereby there, the precise manner in which the additional plates are activated is not disclosed. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to make available a powder press of the stated type, in which seals of piston/cylinder units, which can hydraulically activate or apply pressure to additional plates, with reference to the die plate, the upper yoke and/or the lower yoke, are kept free of powder to the greatest possible extent. 
     These and other objects are achieved by a powder press according to the invention. 
     In this connection, a powder press having an upper yoke, a lower yoke, and tension elements that are in effect between the upper yoke and the lower yoke, as well as having a die plate that is guided parallel to the tension elements, and having at least one additional plate, preferably configured as a lower plate, which is also guided parallel to the tension elements, which plate can be hydraulically activated, with reference to the die plate, the upper yoke and/or the lower yoke, or to which plate pressure can be applied, via a cylinder/piston unit, can be characterized in that the cylinder of the cylinder/piston unit is disposed facing away from the die plate and/or the additional plate, preferably below the additional plate. 
     If it is suitably configured, such a powder press can be guided with greater precision and can have a low construction height. In total, the powder press can then be configured in such a manner that simple assembly and the disassembly are possible. 
     The placement of the cylinders, facing away from the die plate and/or from the additional plate, is particularly suitable for powder presses having an adapter on which the die plate is provided, which plate is accommodated on a die accommodation plate that accommodates the adapter, and which in turn comprises a head plate that is in effect on the head side of the die plate, a foot plate that is in effect on the foot side of the die plate, and a guide for the die plate that is in effect between the head plate and the foot plate, whereby the piston/cylinder unit supports itself on the head plate, on the foot plate, or on a module rigidly connected with the head plate or foot plate. Therefore the adapter forms a unit that is structurally closed in itself and stable, which unit has not only the die plate but also the additional plate, in displaceable manner. 
     Preferably, the cylinder is disposed on the additional plate, so that—together with the characteristic that it is disposed to face away from the die plate or from the additional plate—any seals of the cylinder/piston unit also face away from the die plate, and therefore powder can be kept away from the seals, to the greatest possible extent, as a result of the design. In this way, in particular, a basic idea of the present invention can be implemented, according to which not the pistons but rather the cylinders of the cylinder/piston unit are to be moved. This arrangement ultimately also brings about more stable guidance, if the remainder of the powder press or the remainder of the adapter is suitably configured. 
     The powder press has a particularly compact construction if the die plate and the additional plate have a common guide. In this connection, the die plate can particularly guide the additional plate. 
     Likewise, the additional plate can guide a further additional plate, so that particularly stable guidance can be guaranteed by means of the guidance of the plates relative to one another. 
     The guidance can be further stabilized if the cylinder is part of the additional plate guide, which ultimately can lead to the result that the entire powder press has a significantly more compact construction. With this arrangement, it might be possible to do without additional guides or supplemental guide arms or other guide arrangements, which must reach particularly from guide rods disposed further outward radially to additional plates disposed radially far inward, or the number and massiveness of such guides can be minimized. 
     In order to keep the oil requirement to a minimum, the piston can be configured to run synchronously with a further piston, or can be switched differentially. 
     Also, the surface area ratio of two piston/cylinder units can be selected to be 1:1, in order to thereby simplify the regulation behavior. In this connection, it is understood that with regard to the surface area ratio, specific tolerances, which can amount to as much as 10%, can certainly be tolerated, because in this way, the regulation behavior continues to be improved as compared with the state of the art. 
     It is understood that the characteristics of the solutions described above or in the claims can also be combined, in order to be able to implement the advantages cumulatively, accordingly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention. 
       In the drawings, wherein similar reference characters denote similar elements throughout the several views, 
         FIG. 1  shows a first embodiment of a powder press in a schematic cross-section; 
         FIG. 2  is a horizontal section through the powder press according to  FIG. 1 ; 
         FIG. 3  shows a second embodiment of a powder press, in partial cross-section; and 
         FIG. 4  shows the powder press according to  FIG. 3  in a horizontal section. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Turning now in detail to the drawings, the powder presses  100 ,  200  shown in  FIGS. 1-4  have an upper yoke  1  and a lower yoke  2 , in each instance, as well as tension elements  3  (not shown in  FIG. 3 , because they are sufficiently known), with a die plate  7  provided to be axially displaceable relative to them, which plate, in these exemplary embodiments, is disposed on an adapter  6  and held by a die accommodation plate  4 , which in turn is guided on the press frame formed by the upper yoke  1 , lower yoke  2 , and tension element  3 . 
     The powder presses  100 ,  200  have punches  5  that are used as an upper punch or lower punch, whereby, for example, the lower punch can be used for displacement of the die accommodation plate  4  or of the die plate  7 , while the upper punch can serve for application of the pressing force. 
     In the case of the powder presses  100 ,  200  explained as examples here, the punch  5  that is used as a lower punch is structurally implemented by means of cylinders  8  that are disposed on the upper yoke  1  and the lower yoke  2 , in each instance, and pistons  9  that are provided on the die accommodation plate  4 , whereby not only the cylinders  8  but also the pistons  9  surround passage openings  10  through the upper yoke  1 , the lower yoke  2 , and the die accommodation plate  4 , as well as the tension elements  3 . This arrangement allows a particularly compact design and also makes it possible here to reduce the risk that powder gets to the seals between cylinders  8  and pistons  9  to a minimum. 
     Although the upper punch  5  is provided only on the upper yoke  1  in the exemplary embodiment shown in  FIGS. 1 and 2 , the punch  5  used as an upper punch in the exemplary embodiments shown in  FIGS. 3 and 4  is also implemented by means of cylinders  26  disposed on the upper yoke  1  and lower yoke  2 , as well as complementary pistons  27  that are provided on the die accommodation plate  4 , in each instance. In this connection, the cylinders  8 ,  26  or pistons  9 ,  27  of the punches  5  are oriented diagonal to one another, in each instance, as is particularly shown in  FIG. 4 . In this manner, the forces can be uniformly applied. Furthermore, a powder press  200  configured in such a manner has a particularly compact construction. 
     The adapter  6  in turn comprises a head plate  11 , a foot plate  12 , and a guide  13 , which is formed by guide rods  14  in this exemplary embodiment. 
     Below the die plate  7 , multiple additional plates  17  configured as lower plates are disposed on the adapter, which plates are also guided on the guide  13 , directly or indirectly. In this connection, the uppermost additional plate  17  is guided directly on the guide rods  14 , while the further additional plates  17  are indirectly guided on the guide  13 , by way of the upper additional plates  17 , in each instance. 
     The additional plates  17  can be displaced or pressure can be applied to them by way of cylinder/piston units  18 , in each instance. For this purpose, cylinders  19  are provided on each additional plate  17 , which are configured to face downward, in other words away from the additional plate  17 , in each instance, or from the die plate  7 . In this way, it is possible to reduce the risk that powder collects on the seals of the cylinder/piston units  18  to a minimum. 
     The cylinders  19  of the upper additional plates  17  furthermore serve to guide the lower additional plates  17 , which guarantees a particularly compact construction and compact guidance axially with regard to a center axis  23  of the overall arrangement. 
     Pistons  20  face downward, proceeding from the cylinders  19 , in which pistons, in turn, flow  21  and return  22  to and from the cylinders  19  are provided. In this manner, the overall arrangement has a particularly compact structure. 
     Furthermore, an additional guide  24  configured in the form of guide rods is provided on the foot plate  12  of the adapter  6 , which guide carries clamping and movement cylinders  25  that can also be utilized for tool installation. 
     Although only a few embodiments of the present invention have been shown and described, it will be apparent that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.