Patent Publication Number: US-7906049-B2

Title: Method for filling a foam mixture in a cavity of a metal mold and an apparatus for molding a mold

Description:
TECHNICAL FIELD 
     This invention relates to a method for filling a foam mixture in a cavity of a metal mold and an apparatus for molding a mold. Particularly, it relates to a method for filling a foam mixture composed of a mixture of granular aggregate, water-soluble binders, and water in a horizontally-split or a vertically-split metal mold, by pressurizing and injecting it into the cavity of the metal mold. This invention also relates to an apparatus for molding a mold using this method. 
     BACKGROUND OF THE INVENTION 
     This applicant has already provided an apparatus for molding a mold. 
     The apparatus can mold a mold by pressurizing a foam mixture composed of granular aggregate, water-soluble binders, and water, and injecting it into a cavity of a heated metal mold. The apparatus is comprised of: 
     a hollow rectangular-parallelepiped body having a bottom plate disposed at a lower opening of the body, the bottom plate having an injection hole to inject the foam mixture, 
     a means for containing the foam mixture having functions as a mixing bath to mix granular aggregate, water-soluble binders, and water, and as a pressurized vessel to inject the foam mixture into a metal mold, and 
     a means for closing and opening the injection hole.
     Patent document 1: International Patent Laid-open Publication No. WO 2005/089984 A1   

     In this conventional apparatus for molding a mold, there is a problem in that when the foam mixture is pressurized and injected into the cavity of the metal mold, air in the cavity causes defects in the mold. 
     This invention intends to solve that problem. Namely, the purpose of this invention is to provide a method for filling a foam mixture in a cavity of a metal mold without causing defects in the mold, and to provide an apparatus for molding a mold by using the method. 
     SUMMARY OF THE INVENTION 
     To solve the above problem, the method of the invention has the following features: 
     A method for filling a foam mixture in a cavity of a horizontally-split metal mold by pressurizing the mixture composed of granular aggregate, water-soluble binders, and water, and injecting the mixture into the cavity of the metal mold, the method comprising: 
     a step for preparing the horizontally-split metal mold having a filling port communicating with the cavity, which port is disposed at a side and near abutting surfaces of the horizontally-split metal mold, 
     a step for connecting a discharging port of a means for injecting the foam mixture to the filling port of the horizontally-split metal mold, wherein the means for injecting the foam mixture comprises a mixing bath to accommodate and mix the granular aggregate, the water-soluble binders, and the water, and a mechanism for pushing up the mixture in the mixing bath, wherein the mixing bath is cylindrical and has an opening at its upper end, a bottom plate at its lower end, and the discharging port at its side, 
     a step for pushing up the foam mixture in the mixing bath by driving the mechanism for pushing up the mixture, 
     a step for discharging the foam mixture from the discharging port, and for injecting the mixture into the filling port, and 
     a step for filling the cavity with the foam mixture while the mixture pushes out air in the cavity. 
     The method of also has the following features. 
     A method for filling a foam mixture in a cavity of a vertically or horizontally-split metal mold by pressurizing the mixture composed of granular aggregate, water-soluble binders, and water, and injecting the mixture into the cavity of the metal mold, the method comprising: 
     a step for preparing the vertically-split metal mold having a filling port communicating with the cavity, which port is disposed near the lower portion of its abutting surface, or the horizontally-split metal mold having a filling port communicating with the cavity, which port is disposed at its bottom surface, 
     a step for connecting an opening of a means for injecting the foam mixture to the filling port of the vertically or horizontally-split metal mold, wherein the means for injecting the mixture comprises a mixing bath to accommodate and mix the granular aggregate, the water-soluble binders, and the water, and a mechanism for pushing up the mixture in the mixing bath, wherein the mixing bath is cylindrical and has an opening at its upper end and a bottom plate at its lower end, 
     a step for pushing up the foam mixture in the mixing bath by driving the mechanism for pushing up the mixture, 
     a step for injecting the foam mixture into the filling port, and 
     a step for filling the cavity with the foam mixture while the mixture pushes out air in the cavity. 
     For the present invention, when the discharging port of the means for injecting the foam mixture is connected to the filling port of the horizontally-split metal mold, it is preferable to connect them by horizontally moving the means for injecting the mixture. Further, when the opening of the means for injecting the foam mixture is connected to the filling port of the vertically-split metal mold, it is preferable to connect them by horizontally and vertically moving the means for injecting the mixture. 
     For the present invention, it is preferable to heat the horizontally or vertically-split metal mold by an electrical heater. 
     Since the invention of has the following features, 
     a method for filling a foam mixture in a cavity of a horizontally-split metal mold by pressurizing the mixture composed of granular aggregate, water-soluble binders, and water, and injecting the mixture into the cavity of the metal mold, the method comprising: 
     a step for preparing the horizontally-split metal mold having a filling port communicating with the cavity, which port is disposed at a side and near abutting surfaces of the horizontally-split metal mold, 
     a step for connecting a discharging port of a means for injecting the foam mixture to the filling port of the horizontally-split metal mold, wherein the means for injecting the foam mixture comprises a mixing bath to accommodate and mix the granular aggregate, the water-soluble binders, and the water, and a mechanism for pushing up the mixture in the mixing bath, wherein the mixing bath is cylindrical and has an opening at its upper end, a bottom plate at its lower end, and the discharging port at its side. 
     a step for pushing up the foam mixture in the mixing bath by driving the mechanism for pushing up the mixture, 
     a step for discharging the foam mixture from the discharging port, and for injecting the mixture into the filling port, and 
     a step for filling the cavity with the foam mixture while the mixture pushes out air in the cavity, 
     the invention can prevent an unfilled portion of the foam mixture from being formed in the cavity. Namely, this invention has an excellent effect. That is, it prevents a mold with defects in its inside from forming. 
     Since the invention of also has the following features, i.e., 
     a method for filling a foam mixture in a cavity of a vertically or horizontally-split metal mold by pressurizing the mixture, which is composed of granular aggregate, water-soluble binders, and water, and injecting the mixture into the cavity of the metal mold, the method comprising: 
     a step for preparing the vertically-split metal mold having a filling port communicating with the cavity, which port is disposed near the lower portion of its abutting surface, or the horizontally-split metal mold having a filling port communicating with the cavity, which port is disposed at its bottom surface, 
     a step for connecting an opening of a means for injecting the foam mixture into the filling port of the vertically or horizontally-split metal mold, wherein the means for injecting the mixture comprises a mixing bath to accommodate and mix the granular aggregate, the water-soluble binders, and the water, and a mechanism for pushing up the mixture in the mixing bath, wherein the mixing bath is cylindrical and has an opening at its upper end and a bottom plate at its lower end, 
     a step for pushing up the foam mixture in the mixing bath by driving the mechanism for pushing up the mixture, 
     a step for injecting the foam mixture into the filling port, and 
     a step for filling the cavity with the foam mixture while the mixture pushes out air in the cavity, 
     the invention can prevent an unfilled portion of the foam mixture from being formed in the cavity. Namely, this invention has an excellent effect. That is, it prevents a mold having defects inside it from forming. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an elevational view and a partial sectional view of an apparatus for molding a mold. It is an embodiment to execute the method of the invention. 
         FIG. 2  shows a cross sectional view at line A-A in  FIG. 1 . 
         FIG. 3  shows an elevational view and a partial sectional view of an apparatus for molding a mold. It is a further embodiment to execute the method of the invention. 
         FIG. 4  shows a cross sectional view at line B-B in  FIG. 3 . 
         FIG. 5  shows a partial left side view of  FIG. 3 . 
         FIG. 6  shows a partial cross sectional view at line C-C in  FIG. 3 . 
         FIG. 7  shows an elevational view and a partial sectional view of an apparatus for molding a mold. It is another embodiment to execute the method of the invention. 
         FIG. 8  shows a partial cross sectional view at line D-D in  FIG. 7 . 
     
    
    
     PREFERRED EMBODIMENTS OF THE INVENTION 
     Below, the details of one embodiment of the apparatus for molding a mold used for executing the method of the invention of is explained based on  FIGS. 1 and 2 . As they show, the apparatus for molding a mold comprises: 
     a horizontally-split metal mold  4  comprising a filling port  2  communicating with a cavity  1 , which port is disposed at the left side of an abutting surface of the metal mold  4 , and a mechanism  3  for pushing a mold out, 
     a mechanism  5  for opening and closing the horizontally-split metal mold  4 , 
     a means  9  for injecting a foam mixture comprising a mixing bath  7  to accommodate and mix granular aggregate, water-soluble binders, and water, and a mechanism  8  for pushing up the mixture in the mixing bath  7 , wherein the mixing bath  7  is cylindrical and has an opening at its upper end, a bottom plate  23  at its lower end, and a discharging port  6  to discharge the mixture at its side, and wherein the discharging port  6  can be connected to the filling port  2  of the horizontally-split metal mold  4 . 
     a means  10  for mixing the granular aggregate, the water-soluble binders, and the water accommodated in the mixing bath  7  of the means  9  for injecting the mixture, wherein the means  10  for mixing the mixture is disposed at a location that is apart from the mixing bath  7 , and 
     a means  11  for closing the opening disposed at the upper end of the mixing bath  7  of the means  9  for injecting the mixture, wherein the means  11  for closing the opening is disposed at a location that is apart from the mixing bath  7 , 
     wherein the horizontally-split metal mold  4  can be heated by an electrical heater. 
     The mechanism  5  for opening and closing the horizontally-split metal mold  4  comprises: 
     a base  13  supporting a lower mold  12  of the horizontally-split metal mold  4  on its upper surface, 
     four guide rods  14 ,  14  disposed at the four corners of the upper surface of the base  13 , 
     an upper frame  15  connected to the upper ends of the guide rods  14 ,  14 , 
     an ascending and descending frame  17  holding an upper mold  16  of the horizontally-split metal mold  4  at its lower surface, wherein the frame  17  can slidably move up and down along the guide rods  14 ,  14 , and 
     a cylinder  18  extending downward and disposed at the central portion of the upper surface of the upper frame  15 , wherein the lower end of the piston rod of the cylinder  18  is connected to the central portion of the upper surface of the ascending and descending frame  17 . 
     The upper mold  16  of the horizontally-split metal mold  4  can be lowered and lifted by the extending and contracting movement of the cylinder  18  by means of the ascending and descending frame  17 . 
     Further, a cylinder  19 , extending upward, is disposed at the central portion of the base  13 . The cylinder  19  can push up the lower portion of the mechanism  3  for pushing a mold out. 
     Further, a mechanism  21  for pushing the mechanism  3  down is disposed at the ascending and descending frame  17 . The mechanism  21  comprises a plurality of compression coil springs  20 ,  20  to push down the upper portion of the mechanism  3 . 
     The mechanism  8  for pushing up the foam mixture of the means  9  for injecting the mixture comprises a bottom plate  23  disposed in the mixing bath  7 , which plate  23  can slidably move up and down, and a cylinder  24  extending upward and disposed at the bottom portion of the mixing bath  7 , wherein the upper end of the piston rod of the cylinder  24  is connected to the lower surface of the bottom plate  23 . 
     The means  9  for injecting the foam mixture is disposed at the left side of the horizontally-split metal mold  4 , and can move to the right by means of a carrier  25 . The carrier  25  can move on a pair of horizontal rails  27  by means of a plurality of wheels  26 ,  26  having a V-shaped groove. The pair of rails  27  are disposed at a side base  28 , which is located at the left side of the base  13 . Further, a horizontal cylinder  30  is disposed on the side base  28  by means of a supporting member  29 . The distal end of the piston rod of the cylinder  30  is connected to the left outer side of the mixing bath  7 . The means  9  for injecting the foam mixture can horizontally reciprocate by the extending and contracting movements of the cylinder  30 . 
     The means  10  for mixing the foam mixture is disposed above the means  9  for injecting the mixture by means of a supporting member  31 . It is disposed at the upper frame  15  of the mechanism  5  for opening and closing the metal mold  4 . The means  10  comprises mixing blades  32 , a downward-facing motor  33  to rotate the mixing blades  32 , and a cylinder  34  extending downward to lift and lower the motor  33 . 
     The means  11  for closing the opening of the mixing bath  7  is disposed above the means  9  for injecting the foam mixture by attaching the means  11  to the lower surface of the upper frame  15  of the mechanism  5  for opening and closing the metal mold  4 . The means  11  comprises a lid  35 , and a cylinder  36  extending downward to lift and lower the lid  35 . 
     As shown in  FIG. 2 , a plugging means  37  for closing the discharging port  6  of the mixing bath  7  is disposed between the horizontally-split metal mold  4  and the means  9  for injecting the foam mixture. The plugging means  37  comprises a plug  38  that is comprised of a horizontal cylinder, and another horizontal cylinder  39 . The piston rod of the cylinder of the plug  38  is insertable in the discharging port  6 . The plug  38  is connected to the distal end of the piston rod of the cylinder  39 . 
     Below, the processes for molding a mold are explained based on  FIG. 1 , which shows the initial state of the apparatus. After preheating the upper and the lower mold  16 ,  12  of the horizontally-split metal mold  4  up to a predetermined temperature, the granular aggregate, the water-soluble binders, and the water are charged in the mixing bath  7  of the means  9  for injecting a foam mixture. Then, the piston rod of the plug  38  of the plugging means  37  is inserted into the discharging port  6  of the mixing bath  7 . Next, the mixing blades  32  are inserted into the mixing bath  7  by extending the cylinder  34  of the means  10  for mixing the foam mixture. The granular aggregate, the water-soluble binders, and the water are mixed by rotating the mixing blades  32  by means of the motor  33 , to form the foam mixture. After mixing them, the motor  33  is stopped. Then, the mixing blades  32  are lifted up by contracting the cylinder  34 . Next, after the piston rod of the plug  38  is removed from the discharging port  6 , the plug  38  is taken out from between the horizontally-split metal mold  4  and the means  9  for injecting a foam mixture, by contracting the cylinder  39  of the plugging means  37 . Next, the means  9  for injecting a foam mixture is moved to the right by extending the cylinder  30 , and then the discharging port  6  of the mixing bath  7  is connected to the filling port  2  of the horizontally-split metal mold  4 . Then the opening disposed at the upper surface of the mixing bath  7  is closed by the lid  35  by extending the cylinder  36 . 
     Next, the bottom plate  23  of the mechanism  8  for pushing up the foam mixture is lifted by extending the cylinder  24 . By the movement of the bottom plate, the foam mixture is discharged from the discharging port  6  and injected into the cavity  1  of the horizontally-split metal mold  4  through its filling port  2 . The cavity  1  of the metal mold  4  is filled with the foam mixture while the mixture presses out the air in the cavity  1  through the abutting surface of the upper and the lower mold  16 ,  12  of the metal mold  4 , and through a clearance between the upper and the lower mold  16 ,  12  and the pushing rods of the mechanism  3  for pushing a mold out. After the foam mixture in the cavity  1  has hardened by the heat of the horizontally-split metal mold  4 , the upper mold  16  is separated from the lower mold  12 , and lifted by contracting the cylinder  18  of the mechanism  5  for opening and closing the horizontally-split metal mold  4 . Then, by the action of the compression coil springs  20 ,  20  of the mechanism  21  for pushing the mechanism  3  down, the upper portion of the mechanism  3  for pushing a mold out is lowered. The hardened foam mixture is separated from the upper mold  16  and placed on the lower mold  12 . Next, the lower portion of the mechanism  3  for pushing the mold out is lifted by extending the cylinder  19 . By the action of the lower portion of the mechanism  3 , the hardened foam mixture is separated from the lower mold  12  and lifted up. Based on the procedures explained in the above paragraphs, a required mold can be produced. 
     Below, the details of another embodiment of the apparatus for molding a mold used for executing the method of the invention is explained based on  FIGS. 3-6 . As shown in  FIGS. 3 ,  4 , and  5 , the apparatus for molding a mold comprises: 
     a vertically-split metal mold  54  comprising filling ports  52  communicating with a cavity  51 , which ports are disposed at a lower side of an abutting surface of the metal mold  54 , and a mechanism  53  for pushing a mold out, 
     a mechanism  55  for opening and closing the vertically-split metal mold  54 , 
     a means  58  for injecting a foam mixture comprising a mixing bath  56  to accommodate and mix granular aggregate, water-soluble binders, and water, and a mechanism  57  for pushing up the mixture in the mixing bath  56 , wherein the mixing bath  56  has a cylindrical shape having an opening at its upper end, and a bottom plate  72  at its lower end, and wherein the opening of the mixing bath  56  can be connected to the filling ports  52  of the vertically-split metal mold  54 . 
     a means  59  for mixing the granular aggregate, the water-soluble binders, and the water accommodated in the mixing bath  56  of the means  58  for injecting the mixture, wherein the means  59  for mixing the mixture is disposed at a location that is apart from the mixing bath  56 , and 
     a means  60  for connecting the opening of the mixing bath  56  of the means  58  for injecting the mixture to the filling ports  52  of the vertically-split metal mold  54 , wherein the means  60  is disposed at a location that is apart from the mixing bath  56 , wherein the vertically-split metal mold  54  can be heated by an electrical heater. 
     As shown in  FIG. 3 , the mechanism  55  for opening and closing the vertically-split metal mold  54  comprises: 
     a base  61  having a U-shaped structure, 
     a fixed die base  63  disposed at a top surface of the left portion of the base  61 , wherein a left mold  62  of the vertically-split metal mold  54  is attached to the fixed die base  63 , 
     a frame  64  disposed at a top surface of the right portion of the base  61 , 
     two tying bars  65 ,  65  extending between the fixed die base  63  and the frame  64 , wherein the two tying bars are disposed with a predetermined interval in the front-rear direction, and face each other, 
     a movable die base  67  slidably disposed at the two tying bars  65 ,  65 , wherein a right mold  66  of the vertically-split metal mold  54  is attached to the movable die base  67 , and 
     a horizontal cylinder  68  disposed at the center portion of the frame  64  for reciprocating the movable die base  67 , 
     wherein the right mold  66  of the vertically-split metal mold  54  can reciprocate horizontally by extending and contracting the cylinder  68  by means of the movable die base  67 . 
     The mechanism  70  is disposed at the fixed die base  63  for pushing the left portion of the mechanism  53 , for pushing a mold out, by means of compression coil springs  69 ,  69 . Further, a horizontal cylinder  71  is disposed at the central portion of the movable die base  67  for pushing the right portion of the mechanism  53 , for pushing a mold out. 
     As shown in  FIG. 3 , the mechanism  57  for pushing up the foam mixture of the means  58  for injecting the mixture comprises a bottom plate  72  disposed in the mixing bath  56 , which plate  72  can slidably move up and down, and a cylinder  73  extending upward and disposed at the bottom portion of the mixing bath  56 , wherein the upper end of the piston rod of the cylinder  73  is connected to the lower surface of the bottom plate  72 . 
     The means  58  for injecting the foam mixture can move under the vertically-split metal mold  54  by means of a carrier  74 . The carrier  74  can move on a pair of horizontal rails  76  by means of a plurality of wheels  75 ,  75 , each having a V-shaped groove. The carrier  74  is driven by means of a rack and pinion mechanism, wherein the pinion is attached to an output shaft of a motor, and wherein the rack is disposed at the carrier  74 . The pair of rails  76 ,  76  are disposed at a side base  80 , which is located at the left side of the base  61 . Two special cylinders  81 ,  81  are disposed at the upper surface and both sides of the carrier  74  by means of supporting members  82 ,  82 . The main bodies of the special cylinders  81 ,  81  can be reciprocated horizontally. 
     As shown in  FIG. 3 , the means  59  for mixing the foam mixture is disposed above the means  58  for injecting the mixture by means of a supporting member  83 . The supporting member  83  is disposed at the fixed die base  63  of the mechanism  55  for opening and closing the vertically-split metal mold  54 . The means  59  comprises mixing blades  84 , a downward-facing motor  85  to rotate the mixing blades  84 , and a cylinder  86  extending downward to lift and lower the motor  85 . 
     As shown in  FIG. 6 , the means  60  for connecting the opening of the mixing bath  56  to the filling ports  52  of the vertically-split metal mold  54  comprises: 
     a main structure  88  having communicating holes  87  vertically extending and passing through it, and 
     a supporting structure  90  that is disposed between the main bodies of the two special cylinders  81 ,  81 , and that supports the main structure  88  by means of coil springs  89 ,  89 . 
     As shown in  FIG. 3 , the means  60  can independently and horizontally reciprocate by the movement of the special cylinders  81 ,  81 . 
     As shown in  FIG. 3 , a means  91  for cleaning the communicating holes  87  of the main structure  88  of the connecting means  60  is disposed above the connecting means  60  by means of a supporting structure  92  attached to the fixed die base  63 . As shown in  FIG. 6 , the means  91  for cleaning the communicating holes  87  comprises a cylinder  93  extending downward, and cleaning rods  94  fixed to the distal end of the piston rod of the cylinder  93 . 
     Further, as shown in  FIG. 3 , a cylinder  95 , extending upward, is disposed below the means  58  for injecting the mixture and just under the vertically-split metal mold  54  to push up the injecting means  58  and the connecting means  60  and to abut the connecting means  60  at the lower surface of the metal mold  54 . 
     Below, the processes for molding a mold are explained based on  FIG. 3 . It shows the initial state of the apparatus. After preheating the left and the right mold  62 ,  66  of the vertically-split metal mold  54  up to predetermined temperature, the granular aggregate, the water-soluble binders, and the water are charged in the mixing bath  56  of the means  58  for injecting a foam mixture. Then, the mixing blades  84  are inserted into the mixing bath  56  by extending the cylinder  86  of the means  59  for mixing the foam mixture. The granular aggregate, the water-soluble binders, and the water are mixed by rotating the mixing blades  84  by means of the motor  85 , to form the foam mixture. After mixing them, the motor  85  is stopped. Then, the mixing blades  84  are lifted up by contracting the cylinder  86 . Next, the means  58  for injecting a foam mixture is moved under the vertically-split metal mold  54  by means of the carrier  74  by forwardly driving the motor  77 . The means  60  for connecting the opening of the mixing bath  56  to the filling ports  52  of the vertically-split metal mold  54  is also moved to the right. Then, the connecting means  60  is further moved by the movement of the special cylinders  81 ,  81  so that the communicating holes  87  of the main structure  88  of the connecting means  60  come to just under the filling ports  52  of the metal mold  54 . 
     The means  58  for injecting a foam mixture and the main structure  88  of the means  60  for connecting the opening of the mixing bath  56  to the filling ports  52  of the vertically-split metal mold  54  are lifted by extending the cylinder  95 . Then, the opening of the mixing bath  56  of the means  58  for injecting a foam mixture is connected to the filling ports  52  through the main structure  88  Next, the bottom plate  72  of the mechanism  57  for pushing up the foam mixture is lifted by extending the cylinder  73 . By the movement of the bottom plate, the foam mixture is discharged from the opening of the mixing bath  56  and injected into the cavity  51  of the vertically-split metal mold  54  though its filling ports  52 . The cavity  51  of the method mold  54  is filled with the foam mixture while the mixture presses out the air in the cavity  51  through the abutting surface of the left and the right mold  62 ,  66  of the metal mold  54 , and through a clearance between the left and the right mold  62 ,  66  and the pushing rods of the mechanism  53  for pushing a mold out. After the cavity  51  is filled with the foam mixture, the means  58  for injecting a foam mixture and the main structure  88  are lowered by contracting the cylinder  95 . Then, the injecting means  58  and the connecting means  60  are returned to the initial position shown by  FIG. 3  by means of the carrier  74  by reversely driving the motor  77 . 
     After the foam mixture in the cavity  51  has hardened by the heat of the vertically-split metal mold  54 , the right mold  66  is separated from the left mold  62  by contracting the cylinder  68 . Then, the left portion of the mechanism  53  for pushing a mold out is pushed by the compression coil springs  69 ,  69  of the mechanism  70 . By the movement of the left portion of the mechanism  53 , the hardened foam mixture is pushed out of the left mold  62  while it remains in the right mold  66 . Next, by pushing the right portion of the mechanism  53  by extending the cylinder  71 , the hardened foam mixture is separated from the left mold  62 . Based on the processes explained above, a desired mold can be produced. 
     For the embodiment explained in the above paragraphs, although the vertically-split metal mold  54  is used as a metal mold, the horizontally-split metal mold can also bring about the same effects as those produced by the vertically-split metal mold. Namely, as shown in  FIGS. 7 and 8 , an apparatus for molding a mold comprises: 
     a horizontally-split metal mold  105  comprising a plurality of filling ports  103  communicating with the cavity  102 , which ports are disposed at the lower surface of a lower mold  101 , and a mechanism  104  for pushing a mold out, wherein the horizontally-split metal mold  105  can be heated, 
     a mechanism  106  for opening and closing the horizontally-split metal mold  105 , 
     a means  109  for injecting a foam mixture comprising a mixing bath  107  to accommodate and mix granular aggregate, water-soluble binders, and water, and a mechanism  108  for pushing up the mixture in the mixing bath  107 , wherein the mixing bath  107  has a cylindrical shape having an opening at its upper end and a bottom plate at its lower end, and wherein the opening of the mixing bath  107  can be connected to the filling ports  103  of the horizontally-split metal mold  105 , 
     a means  110  for mixing the granular aggregate, the water-soluble binders, and the water accommodated in the mixing bath  107  of the means  109  for injecting the mixture, wherein the means  110  is disposed at a location that is apart from the mixing bath  107 , and 
     a means  111  for connecting the opening of the mixing bath  107  of the means  109  for injecting the mixture to the filling ports  103  of the horizontally-split metal mold  105 , wherein the means  111  is disposed at a location that is apart from the mixing bath  7 . 
     The mechanism  106  for opening and closing the horizontally-split metal mold  105  comprises: 
     a base  112  supporting on its upper surface a lower mold  101  of the horizontally-split metal mold  105 , 
     four guide rods  113 ,  113  disposed at four respective corners of the upper surface of the base  112 , 
     an upper frame  114  connected to the upper ends of the guide rods  113 ,  113 , 
     an ascending and descending frame  116  holding an upper mold  115  of the horizontally-split metal mold  105  at its lower surface, wherein the frame  116  can slidably move up and down along the guide rods  113 ,  113 , and 
     a cylinder  117  extending downward and disposed at the central portion of the upper surface of the upper frame  114 , wherein the lower end of the piston rod of the cylinder  117  is connected to the central portion of the upper surface of the ascending and descending frame  116 . 
     The upper mold  115  of the horizontally-split metal mold  105  can be lowered and lifted by the extending and contracting movements of the cylinder  117  by means of the ascending and descending frame  116 . 
     Further, a mechanism  119  for pushing up the mechanism  104  for pushing a mold out is disposed at the base  112 . The mechanism  119  can push up the lower portion of the mechanism  104  by means of a plurality of compression coil springs  118 ,  118 . A cylinder  120  extending downward is disposed at the central portion of the ascending and descending frame  116 . The cylinder  120  can push down the upper portion of the mechanism  104 . 
     Further, a cylinder  121 , extending upward, is disposed below the means  109  for injecting the mixture and just under the horizontally-split metal mold  105  to push up the injecting means  109  and the connecting means  111  and to abut the connecting means  111  at the lower surface of the metal mold  105 . 
     The means  109  for injecting the foam mixture, the means  110  for mixing the form mixture, and the means  111  for connecting the opening of the mixing bath  107  to the filling ports  103 , have the same features and functions as those of the injecting means  58 , the mixing means  59 , and the connecting means  60 , respectively. Thus, the detailed explanations of these means are omitted. 
     Below, the processes for molding a mold, which processes use the apparatus explained in the above paragraphs, are explained. After preheating the upper and the lower mold  115 ,  101  of the horizontally-split metal mold  105  up to a predetermined temperature, the granular aggregate, the water-soluble binders, and the water are charged in the mixing bath  107  of the means  109  for injecting the foam mixture. Then, the granular aggregate, the water-soluble binders, and the water are mixed in the same way as explained in the embodiment that uses a vertically-split metal mold  54 . After mixing them, the means  109 , for injecting the foam mixture, and the means  111 , for connecting the opening of the mixing bath  107  to the filling ports  103 , are moved to a position which is below the horizontally-split metal mold  105 . Then, the means  111  are moved to just under the metal mold  105 . Next, by extending the cylinder  121 , the opening of the mixing bath  107  of the means  109  for injecting the foam mixture is connected to the filling ports  103  of the metal mold  105  through the connecting means  111 . Then, the foam mixture is injected into the cavity  102  of the metal mold  105  by means of the means  109  for injecting the foam mixture. The cavity  102  is filled with the foam mixture while the mixture presses out the air in the cavity  102  through the abutting surface of the upper and the lower mold  115 ,  101  of the metal mold  105 , and through a clearance between the upper and the lower mold  115 ,  101  and the pushing rods of the mechanism  104  for pushing out a mold. 
     After the cavity  102  is filled with the foam mixture, the means  109  for injecting a foam mixture and the means  111  for connecting the opening of the mixing bath  107  to the filling ports  103  are lowered by contracting the cylinder  121 . Then, the injecting means  109  and the connecting means  111  are returned to the initial position. 
     After the foam mixture in the cavity  102  has hardened by means of the heat of the horizontally-split metal mold  105 , the upper mold  115  is separated from the lower mold  101  by contracting the cylinder  117 . Then, the lower portion of the mechanism  104  for pushing a mold out is pushed by the compression coil springs  118  of the mechanism  119  for pushing up the mechanism  104 . By the movement of the lower portion of the mechanism  104 , the hardened foam mixture is pushed out of the lower mold  101  while it remains in the upper mold  115 . Next, by pushing the upper portion of the mechanism  104  by extending the cylinder  120 , the hardened foam mixture is separated from the upper mold  115 . Based on the processes explained above, a desired mold can be produced.