Abstract:
A machine for production of cores for use in castings includes a platform for supporting two core boxes and a split filler head having dual discharge channels for simultaneously injecting core sand into two core boxes and for simultaneously applying curing gas to core sand injected the two into core boxes.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to method and apparatus for the production of cores used for the creation of cavities in an object formed by casting.  
           [0003]    2. Background Art  
           [0004]    In forming an object by casting, a mold with an inner cavity defining the outer contour of a product to be cast is commonly used. To form a cavity within the casting, a core shaped in the form of the cavity to be formed is typically positioned within the mold. Such cores are commonly produced by a molding process using a core-forming machine. The core forming machine typically includes a core box formed by two opposing mold plates, each provided with a cavity shaped in the form of one half of the core to be formed. The two mold plates are forced together and held together under pressure, to create a cavity defining the core. Core forming machines typically include a sand magazine that is temporarily positioned over the opening in the core box in the core forming process, and sand is forced from the magazine into the opening in core box, typically by compressed air or the like, to form the desired core. The sand magazine is then moved away and a gas magazine is moved into position over the opening and a suitable curing gas is injected into the mold under pressure to cure the sand in the core cavity. Certain additional steps such as vibrating, pressing, vacuum drawing of the core sand, or the like, all well known in the art, may be performed to assure that the core sand flows into all of areas of the mold. The mold plates are then separated to allow the core to be removed.  
           [0005]    A problem with known core forming machines is that they are typically complex and expensive to build and operate and, since each of the necessary core production steps has to be performed individually for each core, it tends to be a time consuming process.  
         SUMMARY OF THE INVENTION  
         [0006]    These and other problems in the prior art are overcome in accordance with the invention by core making apparatus wherein core forming steps, such as filling, injecting curing gas, etc. are applied to multiple core boxes, simultaneously and in parallel, by the use of a single sand magazine and a single gas magazine, under control of a single control complex that controls the core making process and that may perform such additional steps as vibrating, pressing, etc. of the multiple core boxes, simultaneously. In a particular embodiment of the invention, multiple core boxes are disposed adjacent each other and are provided with filler openings. A multi-channel, filler head is provided adjacent upper filler openings of the core boxes, whereby the multiple core boxes are filled simultaneously. Furthermore, a curing gas may be applied simultaneously to the multiple core boxes, via a multi-channel gassing head.  
           [0007]    Advantageously, by the use of a core forming machine incorporating the principles of this invention, a plurality of casting cores may be formed in a time period not substantially greater than typically required for the forming of a single core. Furthermore, modifications to existing core forming apparatus in accordance with the present invention for increasing the output of the core forming apparatus, are relative inexpensive to implement.  
           [0008]    In accordance with one aspect of the invention, a center section is mounted between two core boxes to be filled simultaneously. Advantageously, the center section serves to assure proper alignment of two core boxes with the multi-channel filler and gassing heads.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a front elevational view of a core forming machine incorporating principles of the invention;  
         [0010]    [0010]FIG. 2 is a partial cutaway view of the core-forming machine of FIG. 1 showing the sand magazine in a discharge position;  
         [0011]    [0011]FIG. 3 is a cross-sectional view along line  3 - 3  of FIG. 2;  
         [0012]    [0012]FIG. 4 is a top elevational view along line  4 - 4  of FIG. 1; and  
         [0013]    [0013]FIG. 5 is a cross-sectional view along line  5 - 5  of FIG. 1. 
     
    
     DETAILED DESCRIPTION  
       [0014]    Shown in FIG. 1 is core-forming apparatus  100  arranged for simultaneously forming two cores for use in castings. The core forming apparatus includes a table  104  having a table top  105 , supported on legs  106 . Resting on the table top  105  are two separate core boxes  101 ,  102 . The two core boxes are separated by a center section  130  extending in a direction perpendicular to the table top  105 . The center section  130  is mounted to table top  105  via one or more bolts  139  and serves as an upstanding support for separating the two core boxes  101 ,  102 . As depicted in the drawings, the core boxes  101 ,  102  each comprise two separate core box halves  101 A, B and  102 A, B, respectively. Further supported on the table top  105  are pressure application units  131 ,  132 . Each of the pressure application units includes: a pressure unit  131 A,  132 A; a pressure application head,  131 B,  132 B; and a piston rod  131 C,  132 C. A piston rod extends from each pressure unit to the corresponding pressure application head. Such pressure units are well known in the art and may be hydraulic or pneumatic pressure units, or the like, adapted to apply sufficient pressure to hold the separate halves of core boxes tightly together during the core forming process. The center section  130  is preferably made of steel or similar material, sufficient to withstand pressure applied by the pressure application units  131 ,  132 . Alignment rods  140 A,B and  141 A,B extend between the pressure units  131 A,  132 A and through the box halves  101 A, B and  102 A,B, as well as through the center section  130 , and serve to align the core boxes  101 ,  102 .  
         [0015]    Further shown in FIG. 1 is a sand hopper  150 , supported on an upstanding support  153 . Disposed in alignment with the sand hopper  150  is sand magazine  110  supported on brackets  156 ,  157  mounted on a rotatable shaft  155 . The sand magazine  110  is provided with a filler head  111 . Also shown in FIG. 1 is a gas magazine  120  provided with a gassing head  121  and supported on brackets  166 ,  167  mounted on a rotatable shaft  165 . A control unit  160  controls the filling of the sand magazine  110  from the hopper  150  and the charging of the gas magazine  120  from a gas supply, in a standard and well-known fashion. Furthermore, the control unit  160  controls movement sand magazine  110  and the gas magazine  120  from a filling position, as depicted in FIG. 1, to an unloading position in alignment with the core boxes  101 ,  102 . Sand magazines and gas magazines and control units, such as the control unit  160 , are well known in the art and commercially available.  
         [0016]    Further shown in FIG. 1, are a filler head  111 , attached to the sand magazine  110 , and a gassing head  121 , attached to the gas magazine  120 . Shown in FIG. 2 is a front elevational view of the core boxes  101 ,  102  and a partial cut-away view of the sand magazine  110 , rotated 90 degrees from a sand loading position depicted in FIG. 1. As shown in FIG. 2, the split filler head  111  has two separate discharge channels, i.e. conduits  111 A,  111 B. A cross-sectional view of the split filler head  111 , along line  3 - 3  of FIG. 1 is shown in FIG. 3. In the present embodiment, the gas magazine  120  is provided with a split filler head  121  having a configuration identical to the split filler head  111 .  
         [0017]    During core forming operation, the sand magazine  110  is initially disposed in alignment with a sand hopper  150 , as depicted in FIG. 1, and is supported on a support bracket  155  in a standard fashion. The control unit  160  controls operation of the sand hopper  150 , as well as movement of the sand magazine head  110  and charging and moving of the gas head  120 , in a standard fashion. The control unit  160  also controls the rotatable shafts  155  to which sand magazine support brackets  156  and  157  are mounted, as well as the rotatable shaft  165 , to which the gas head support brackets  166 ,  167  are mounted. In a normal sequence of operations, the control unit  160  moves the sand head  110  from the loading position of FIG. 1 to a position wherein the sand magazine  110  is in alignment with the sand hopper  150  and controls the sand hopper  150  to discharge a specified amount of core sand into the sand magazine  110 . Thereafter, the control unit  160  moves the sand magazine  110  from the loading position to an unloading position by rotating the shaft  155  by 90 degrees and lowering it such that the filler head  111  is adjacent upper surfaces of the two core boxes  101 ,  102 , as depicted in FIG. 2. In this position, the sand magazine  110  is positioned for filling the two core boxes  101 ,  102 , simultaneously. The simultaneous transfer of sand from the single sand head to the two core boxes via the filler head  111 , is controlled in a standard fashion by the control unit  160  by opening an internal valve (not shown in the drawing) in the sand magazine  110 . In this manner, the split filler head  111  allows the two core boxes  101 ,  102  to be filled simultaneously via the two separate legs  111 A,  111 B depicted in FIGS. 2 and 3.  
         [0018]    [0018]FIG. 4 is a top elevational view along line  4 - 4  of FIG. 1. FIG. 4 shows the upper surface of the core boxes  101 ,  102  separated by the center section  130 . As depicted in FIG. 4, the core boxes  101 ,  102  are provided with filler openings  145 ,  146 , respectively. When the split filler head  111  is properly aligned with the core boxes  101 ,  102 , the openings  145 ,  146  of the core boxes are aligned with the openings  111 A,  111 B, respectively, of the filler head  111  shown in FIG. 3. Similarly, when the split gas head  121  is aligned with the core boxes  101 ,  102 , the openings  145 ,  146  are aligned with the openings  111 A,  111 B. Further shown in FIG. 4 are support rods  140  and  140 A. Support rod  140 A is disposed behind the support rods  140  and is not visible in FIGS. 1 and 2.  
         [0019]    In the core forming process, two cores are formed simultaneously by depositing core sand, specifically formulated for use in forming cores, in the two core boxes  101 ,  102 . The core box halves  101 A,  101 B are forced together and against the center section  130  by pressure applied by the hydraulic unit  131 A to application head  131 B. Similarly, the core box halves  102 A,  102 B are forced together and against center section  130  by the pressure applied by the hydraulic unit  132 A to application head  132 B. The pressure applied by the hydraulic units  131 A,  132 A is preferably applied simultaneously and with substantially equal pressure.  
         [0020]    After completion of the filling of the core boxes  101 ,  102  with core sand, the sand magazine  110  is removed to the position shown in FIG. 1 and the gas magazine  120  is moved into the position previously occupied by the sand magazine  110 . All under control of the control unit  160 . As depicted in FIGS. 1 and 5, the gas magazine  120  is provided with a split gassing head  121  having two separate discharge openings  160 ,  161 . The openings  160 ,  161  are to be aligned with the openings  145  and  146  of the core boxes  101 ,  102 , respectively. In this manner, a curing gas is applied simultaneously to the two core boxes  101 ,  102  from the gas magazine  120 .  
         [0021]    [0021]FIG. 5 is a cross-sectional view of gassing head  121  along line  5 - 5 , showing openings  160 ,  161  for discharging a well-known curing gas, or the like into the core boxes  101 ,  102 . When positioned adjacent the core boxes  101 ,  102  the two separate legs of the filler head  121  are in alignment with openings  145 ,  146  of the core boxes  101  and  102 , respectively. An appropriate curing gas is forced from the gas magazine  120  into the core boxes  101 ,  102  in a standard fashion to solidify the sand deposited in the core boxes from the sand magazine  110 . Thereafter, the gas magazine  120  is removed to the position depicted in FIG. 1 and the pressure plates  131 B,  132 B are retracted by operation of the hydraulic cylinders  131 C,  132 C, respectively. The newly formed cores may then be removed from the core boxes  101  and  102  in a standard fashion.  
         [0022]    To prepare the core boxes for a next cycle of core forming, the hydraulic units  131 A and  132 A are again activated to return the core boxes to the closed position depicted in FIG. 1. Furthermore, the gas magazine  120  is moved to a position over the core boxes  101 ,  102 , in the manner depicted for the sand magazine  110  in FIG. 2, and a purging gas is applied to the core boxes in preparation for a next cycle of core forming. Thereafter, the gas magazine  120  is once again returned to the position shown in FIG. 1 and a new cycle of core forming, described above, may be initiated.