Patent Publication Number: US-6662857-B2

Title: Mold comprising outer mold parts and molding material cores inserted into same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims priority to German Patent Application 100 19 310.2 filed Apr. 19, 2000, which application is herein expressly incorporated by reference. 
     FIELD AND BACKGROUND OF THE INVENTION 
     The present invention relates to a mold with outer mold parts and inserted mold material cores. Together, the outer mold parts and material cores form a mold cavity. The outer mold parts can be part of a permanent mold and/or molding material parts/outer cores. 
     To produce complicated moldings, such as cylinder heads, it is necessary to insert molding material cores into the outer mold parts. It is also known to use outer molding material cores. Thus, substantial parts of the outer casting faces are not formed by a metallic mold wall. These parts are formed by outer cores of molding material. This method is particularly suitable for casting aluminum and magnesium alloys. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a mold which can be used for complicated castings. In particular, the mold is suitable for rotary casting. 
     The inner cores including molding material are stacked in layers one above the other. The inner cores are clamped between the outer mold parts and the final covering core of molding material. A continuous force, a going-through uninterrupted force, is applied between the covering core, the inner cores, and the outer mold parts. The mold cavity is formed by surfaces of the outer mold parts, surfaces of the inner cores and the covering core. In accordance with the invention, additional means are not provided to fix the molding material cores in the outer mold cores and to fix the molding material cores between each other. The multi-layer structure enables the production of complicated shapes. By using the final covering core, which is comprised of molding material, it is possible to directly connect a casting container. The covering core preferably comprises at least one ingate aperture and at least one gas exit aperture. 
     According to a further embodiment, the parts of the mold include a base plate and several side parts. The side parts are movable relative to the base plate. The side parts may include two longitudinal side parts. The longitudinal side parts, relative to the base plate, can be displaced outwardly away from the mold cavity in opposite directions. At least one end side part, relative to the base plate, can be pivoted outwardly away from the mold cavity. This measure enables a problem-free structure of the inner cores, which includes several stacked layers. The inner faces of the side parts may include projections which hold additional individual inner cores relative to the base plate. Displaceable bolts or pivotable claws may be arranged at the base plate or at least at two side parts to secure the covering core. The bolts or claws hold the package of molding material cores within a mold such that, even when the mold rotates, displacements between the inner cores cannot occur. 
     An inventive mold is used in a particularly advantageous way if the mold is first stacked on the base plate and then rotated by about 180° around a horizontal axis. The covering core, which includes an ingate aperture, comes downward to rest. Subsequently, a casting container filled with melt for one casting operation is coupled to the covering core. When the assembly is again rotated by 180° around the horizontal axis, the melt flows through the ingate aperture in the covering core into the mold cavity. Thereafter, the melt container is removed and the casting solidifies. After solidification, the mold is removed. The mold is preferably rotated around an axis which extends parallel to the longitudinal extension of the mold cavity. 
     The base plate is provided in the form of a permanent mold part. Ordinarily, the base plate is metal. The outer mold parts can also be permanent mold parts mechanically connected to the base plate. Also, the outer mold parts can be molding material parts. In this case, mechanical clamping means clamp the parts onto the base plate from the sides and from above. Also, the clamping means is connected to the base plate. 
     From the following detailed description, taken in conjunction with the drawings and subjoined claims, other objects and advantages of the present invention will become apparent to those skilled in the art. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention is illustrated in the drawings and described below: 
     FIG. 1 is a plan view partially in section of an inventive mold in a first position after having been assembled. 
     FIG. 2 is a plan view partially in section of the inventive mold in a second position before the casting process starts. 
     FIG. 3 is a plan view partially in section of a second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 will be described jointly. An inventive mold  11  includes a multi-component base plate  12 , side parts  13 ,  14 , each in the form of permanent mold parts, a plurality of inner cores  15 , stacked in several layers one above the other on the base plate  12 , and a covering core  16 . The inner cores  15  and cover core  16  each are of molding material. The plurality of inner cores  15  are clamped in between the base plate  12  and the covering core  16 . A continuous clamping force exists on the inner cores  15 . 
     The side parts  13 ,  14  include mold projections  17 ,  18 . The mold projections  17 ,  18  additionally hold individual inner cores  15  against the base plate  12 . Setting cylinders  19 ,  20  displace the side parts  13 ,  14  in opposite directions relative to the base plate  12 . The cylinders  19 ,  20  can be moved away from one another relative to the illustrated position. Thereafter, the inner cores  15  can be stacked on the base plate  12 . Following this operation, the side parts  13 ,  14  can again be closed, as indicated by the arrows pointing in opposite directions. Once again, the side parts  13 ,  14  return to the indicated position. The covering core  16  is then placed in position. 
     Bolts  21 ,  22  are arranged on the side parts  13 ,  14 . The bolts  21 ,  22  enable assembly and may be slid back relative to the side parts  13 ,  14 . After the covering core  16  has been placed in position, the bolts  21 ,  22  may be moved forward into the illustrated position. Here, the bolts  21 ,  22  hold the covering core  16  relative to the inner core  15  and the side parts  13 ,  14 . 
     The base plate  12  has ejectors  23 ,  24  which are actuated by a setting cylinder  25 . The ejectors  23 ,  24  remove the casting from the mold. The base plate  12  and thus the entire mold  11  can be rotated around a horizontal axis  26 . The axis  26  extends perpendicular relative to the drawing plane. 
     Column  27  supports a pivot arm  28  which carries a casting container  29 . The casting container can be displaced by a setting cylinder  30  parallel to the column  27  on the pivot arm  28 . Also, the column  27  may be rotated about the axis  26 . 
     FIG. 1 shows the finish-assembled mold  11  in its position assumed directly after the stacking operation. The casting container  29  is suspended upside down. The casting container  29  has been removed by the setting cylinder  30  from the mold  11 . Also, the casting container  29  has been pivoted by the pivot arm  28  on the column  27 , by 90° relative to the mold. 
     In FIG. 2, the mold  11 , together with the column  27  and the casting container  29 , has been rotated by 180° around axis  26 . The casting container  29  is still in the same position relative to the mold  11  as shown in FIG.  1 . However, the casting container  29  is now open upwards. Also, the casting container  29  is just being filled by a dispensing ladle  31  with melt  32  for one casting operation. 
     After the casting container  29  is filled, the pivot arm  28  is pivoted 90° relative to the column  27 . Thus, the casting container  29  rests underneath the mold  11  in front of the column  27 . The casting container  29  is then lifted towards the mold  11  by the cylinder  30  until the casting container  29  rests sealingly against the covering core  16 . In the now assumed position, the mold  11  with the coupled casting container  29  is again rotated by 180° around the axis  26 . The melt  32 , weighed to fill the mold cavity, flows through the ingate  33  into the mold cavity. Gas in the cavity is able to escape from the gas exit  34  in the casting container  29 . After completion of the rotating operation and the casting operation, once again the mold  11  assumes the position as shown in FIG.  1 . The casting container  29  is lifted by the setting cylinder  30  from the mold  11  and rotated by the pivot arm  28  back into the position as shown in FIG.  1 . After the metal has solidified, the casting can be removed from the mold by withdrawing the side parts  13 ,  14  and actuating the ejectors  23 ,  24 . 
     The side parts  13 ,  14  may be of molding material. In this case, the bolts  21 ,  22  are replaced by hold-down devices connected to the base plate. 
     FIG. 3 illustrates a second embodiment of the present invention. Here, the elements which are the same are designated with the same reference numerals. Here, pivotable claws  21 ′,  22 ′ replace bolts  21 ,  22 . The claws  21 ′,  22 ′ are arranged at the side parts  13 ,  14 . However, the claws  21 ′ 22 ′ may be at the base plate. 
     While the above detailed description describes the preferred embodiment of the present invention, the invention is susceptible to modification, variation and alteration without deviating from the scope and fair meaning of the subjoined claims.