Abstract:
In order to increase casting production during a filling of a mold from below, whereby an uptake for the casting mass is provided in the molding sand of the mold, immediately after the filling of the mold has been concluded a part of the uptake, which part extends in the molding sand, is interrupted and thus closed off so that the mold can be immediately separated from the casting container.

Description:
FIELD OF THE INVENTION 
     The invention relates to a casting method for filling a mold from below with a casting mass from a casting container through an uptake into the molding sand of the mold and for facilitating the flowing in of the casting mass rising up from below and entering into the mold, and a mold for such a method. 
     BACKGROUND OF THE INVENTION 
     The casting mass is in such a casting method subjected to a feed pressure, which, after casting, must be maintained sufficiently long until the casting mass has rigidified in the mold so that it cannot return into the casting container. Only then is it possible to remove the feed pressure and to exchange the filled mold for a new mold for the next casting. The time required for cooling off of the casting mass filled into the mold slows down the casting process because the filling of a mold via a riser passageway for the casting mass is a very economical method, which can also be used for molds made of molding sand, which molds can be manufactured quickly and in large numbers; the waiting periods required for the cooling off of the casting mass are therefore especially annoying. 
     SUMMARY OF THE INVENTION 
     The basic purpose of the invention is therefore to provide such a method and an associated mold in such a manner that the feed pressure for feeding of the casting mass from the casting container into the mold can cease immediately after the mold has been filled with casting mass. 
     The purpose is attained according to the invention wherein directly after the filling of the mold has been completed, the molding sand in which is provided the uptake is interrupted and is thus closed off so that the mold can be separated from the casting container. The mold and the mold container are flow-coupled in relationship to the casting mass and the feed pressure can thereafter be removed. A new mold can directly thereafter be flow-connected to the casting container so that the casting process can already be started anew when the earlier cast mold has not yet rigidified. Such a casting method can therefore be advantageously utilized in a continuously running manufacturing process. 
     A particularly advantageous development of the invention is experienced by the casting method when the casting mass stored in the casting container is subjected to a pneumatic feed pressure on its surface, and the casting mass is pressed through at least one vertically extending first uptake terminating at one end in the casting mass, and through a second uptake aligned with the first uptake and forming with same a common uptake pipeline for facilitating the filling of the casting mass into the mold provided above the uptake. The entire uptake pipeline extends hereby vertically and is accessible in the area of the second uptake to a constriction carried out in the mold. 
     Thus it is possible that a thin blocking slide, for example a metal strip, is moved into the uptake transversely with respect to its axis and covering its cross section. The metal strip can thereby be guided by a piston rod or also manually into the area of the uptake through the molding sand. It is even easier when the uptake is constricted in a preferably short partial area on a lower part of the mold through a horizontal force of at least one preferably hydraulically operated piston rod, which force is applied transversely with respect to its axis, and moves and/or compresses the molding sand; the uptake is thereby closed off merely by moving and/or compressing the molding sand, whereby immediately after the flow into the uptake is interrupted the feed pressure onto the surface of the casting mass is stopped so that the desired continuous operating process is achieved because the mold can now be immediately replaced. 
     Such a mold, which is suited for the method of the invention, is characterized, for example, in such a manner that a channel is provided in the molding sand, which channel extends preferably into the vicinity of the uptake, is oriented transversely with respect to the axis of the uptake, is formed into the molding sand and is displaced by the piston rod. The channel can be provided with a plug, which plug can be forced into the uptake by the piston rod in such a manner that same is blocked. Instead it is also possible that the channel is designed as a slide guide, in which a disk-shaped slide is provided so that a flow passage provided in the slide and adapted to the flow cross section of the uptake pipeline is just aligned with the uptake, whereby the slide with the help of the piston rod can be moved so far that the uptake pipeline is blocked. In the case of a stationarily arranged mold, the uptake lies either in or parallel to the mold parting plane of the mold, whereas the uptake in a mold, which is lying on its side 90° offset from the aforementioned position, is arranged perpendicularly with respect to the mold parting plane. The channel must be constructed wider in a mold which is lying on its side so that a guiding in and a relative movement of the piston rod for closing of the uptake is possible. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be discussed in greater detail hereinafter in connection with one exemplary embodiment and the drawings, in which: 
     FIG. 1 is a longitudinal cross-sectional view of a casting arrangement with a stationary mold prior to the casting, which arrangement is suitable for the method of the invention; 
     FIG. 2 illustrates the arrangement of FIG. 1 directly after the casting task and the closing of the uptake; 
     FIG. 3 illustrates a casting arrangement as shown in FIGS. 1 and 2 with a slightly changed mold; 
     FIG. 4 illustrates a casting arrangement as shown in FIG. 3 with a special closure part for the uptake of the mold; 
     FIGS. 5 and 6 illustrate a casting arrangement with a further modification of the mold of FIG. 3; and 
     FIGS. 7 to  10  illustrate a casting arrangement for a mold lying on its side, all in a schematically simplified illustration. 
    
    
     DETAILED DESCRIPTION 
     A mold  1 ,  2  according to the invention consists of two vertically divided mold halves  1  and  2  with a mold cavity  3  enclosed by molding sand, into which cavity terminates a central, vertically downwardly directed uptake  4  formed into the molding sand; the uptake  4  with a most advantageously circular cross section terminates at the other end at a free end face  10  of an also vertically designed uptake  8  which is aligned with the uptake  4  and forms therewith an uptake pipeline  4 ,  8  for a casting mass  7  as long as the mold  1 ,  2  is mounted on a casting container  5 ,  6 . The casting container  5 ,  6  is composed of a pot  6  and a head piece  5  mounted on the pot  6 , which head piece tightly closes off the pot  6  and has, aside from the centrally arranged uptake  8 , also a connection  9 , which both terminate at a level above the surface  11  of the liquid casting mass  7  in the pot  6 . 
     The casting mass  7  is force fed into the mold cavity  3  through the uptake pipeline  4 ,  8  when the mold  1 ,  2  is mounted on the casting container  5 ,  6 . This force feeding is caused by the surface  11  being subjected to a pneumatic feed pressure p applied to and through the connection  9  to flow-connect the casting container  5 ,  6  to a compressed-air source (not shown). 
     A hydraulic piston motor  12  is installed at the height of the uptake  4  and directed transversely to its extent, the piston rod  13  of which can be moved into the mold  1 ,  2  in a direction  14  perpendicular to the axis of the uptake  4 , and applies thereby a sand displacement force onto the molding sand provided in the mold. 
     The piston rod  13  applies in the arrangement of FIGS. 1 and 2 its force directly onto the molding sand which completely forms the mold  1 ,  2 . As shown in FIG. 2, the piston rod  13  is moved after casting sufficiently far into the molding sand of the mold  1 ,  2  until the uptake  4  is interrupted by compressed molding sand which is pressed into the cross section of the pathway of the uptake  4  to close off the uptake so that a return of the casting mass  7  already filled into the mold chamber  3  is prevented. It is understood that a further piston rod diametrically opposite to the first one can be provided in order to also correspondingly displace the molding sand on the opposite side of the mold  1 ,  2 , and in order to be able in this manner to constrict the uptake  4  from two sides. 
     In contrast to this, the embodiments of FIGS. 3-6 show an elongate piston rod receiving channel  15  or  16  formed into the molding sand of the mold  1 ,  2 , which channel extends in the direction  14  and corresponds in cross section to the cross section of the piston rod  13 , and extends to the uptake  4  (FIGS. 3,  4 ) or beyond (FIGS. 5,  6 ). 
     Whereas according to FIG. 3 the piston rod receiving channel  15  can solely serve the purpose to ease the work of the piston rod  13 , a plug  17  is in the arrangement of FIG. 4 placed into a preformed fitting receiving channel  16 , which plug can be moved by the piston rod  13  until the uptake  4  is closed. Such a design is particularly advantageous when the molding sand is chemically bound and opposes the piston rod  13  with a suitably high resistance when same is moved into the molding sand. 
     A further embodiment of a casting arrangement of the invention is shown in FIGS. 5,  6  and after the casting task. Here a slide  18  is placed into the channel  16 , which channel extends sufficiently far into the molding sand that the slide  18 , without any further compressing of the molding sand by the piston rod  13 , can be moved a sufficient distance after the casting task has ended so that a flow passage  19  provided in the slide  18 , provided before and during the casting process (FIG. 5) in the area of the uptake  4  and forming a part of the uptake  4 ,  8  is no longer effective (FIG.  6 ), namely it blocks the uptake  4  to the mold  1 ,  2 , and thus also prevents a return of the casting mass  7  from the mold  1 ,  2 . 
     In the casting arrangement illustrated in FIGS. 7 to  10 , the same parts have associated therewith the same reference numerals. This casting arrangement differs from the one according to FIGS. 1 to  6  essentially in such a manner that the mold is lying 90° from the position shown in FIGS. 1-6, which has the advantage that a lesser static pressure builds up within the mold. 
     The mold is moved on a transport track  20  to the casting arrangement, whereat it is lowered so that the uptake  8  closely interfaces with an aligned uptake  4 . The mold is thereafter filled through the uptake  8 , as this is illustrated in FIG.  8 . The pressure piece  21 , which extends into the channel  15 , is moved by a pneumatic cylinder  12  so that, as this is illustrated in FIG. 9, the sand is pressed into the uptake  4  and closes same off. FIG. 10 illustrates the position, in which the uptake  4  is closed off and the pressure piece  21  is again retracted. The mold  1 ,  2  is then lifted and is transported on the transport track  20 . Otherwise this embodiment corresponds with the one described in FIGS. 1 to  6  so that reference is made to these figures.