Patent Publication Number: US-2016228942-A1

Title: Mold forming apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a mold forming apparatus, and more particularly to a mold forming apparatus including: a storage tank that has in its bottom an injection port capable of being opened and closed and that stores a foamed mixture formed by agitating a granular aggregate and an additive; a forming mold that has a runner into which the foamed mixture is introduced through the injection port of the storage tank and that has a cavity for forming the introduced foamed mixture into a mold in a predetermined shape; and pressing means that is disposed so as to correspond to the forming mold and that presses the foamed mixture stored in the storage tank to inject the foamed mixture into the cavity through the runner of the forming mold. 
     BACKGROUND ART 
     Patent Document 1 is known as related art of a mold forming apparatus. Patent Document 1 describes a mold forming apparatus that forms a mold by filling a cavity of a heated mold with a foamed mixture formed by agitating a granular aggregate, a water soluble binder, and water by an injection method, characterized by including: mixture storage means that has a hollow rectangular parallelepiped body having the shape of a rectangular parallelepiped and having a space extending in the vertical direction, that has a bottom plate closing an opening at the lower end of the hollow rectangular parallelepiped body and having injection holes for injecting the foamed mixture, and that has both a function as an agitation tank in which the granular aggregate, the water soluble binder, and the water are agitated, and a function as an injection cylinder that stores the foamed mixture in order to inject the foamed mixture; and plug means capable of closing the injection holes. 
     In such a mold forming apparatus, in general, in order to cause the foamed mixture to entirely fill the cavity of the forming mold, a plurality of runners are formed in the forming mold according to the size, shape, etc. of a mold to be formed, and a plurality of injection holes are formed in the bottom plate of the hollow rectangular parallelepiped body (hereinafter referred to as a “bottom of the storage tank”) so as to correspond to inlets of the runners. In order for the foamed mixture to be reliably injected into the cavity with minimum resistance, the runners are typically formed linearly and parallel to the direction in which the foamed mixture stored in the storage tank is injected. 
     The forming mold is typically formed by a pair of forming molds that can be opened and closed, and is often formed such that abutting surfaces (parting surface) of both the forming molds extend in a direction perpendicular to the direction in which the pressing means presses the foamed mixture, that is, such that the runners are formed in one of the forming molds and the direction in which the forming molds are opened and closed is parallel to the direction in which the pressing means presses the foamed mixture. 
     PRIOR ART DOCUMENTS 
     Patent Documents 
     Patent Document: International Publication No. WO 2005/089984 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     However, in the case where a plurality of runners are formed according to the size, shape, etc. of a mold to be formed such that the runners extend linearly and parallel to the direction in which the foamed mixture is injected as in the related art, injection ports are formed in the bottom of the storage tank so as to correspond to the inlets of the runners. The bottom of the storage tank therefore needs to have substantially the same size as the maximum width of the surface of the forming mold in which the inlets of the runners are formed. In particular, in the case where the storage tank is formed in a cylindrical shape in order to agitate the granular aggregate and the additive to form the foamed mixture by rotating agitating blades in the storage tank, the storage tank is formed such that the diameter of the bottom of the cylindrical storage tank is substantially the same as the maximum width of the surface of the forming mold in which the inlets of the runners are fanned. Accordingly, in the case where the cavity of the forming mold is large or has a complex shape etc., the diameter of the storage tank is increased accordingly, which increases the overall size of the mold forming apparatus and the space required to install the mold Matting apparatus. 
     In the case where the direction in which the forming molds are opened and closed is parallel to the direction in which the pressing means presses the foamed mixture, a large distance is required between the forming mold and the pressing means so that the forming mold does not interfere with the pressing means when opened. This increases the overall size of the mold forming apparatus and the space required to install the mold forming apparatus. Moreover, in the case where the direction in which the forming molds are opened and closed is parallel to the direction in which the pressing means presses the foamed mixture, the runners are formed in one of the forming molds. In this case, the solidified foamed mixture remains in the runners after a mold is formed, and it is difficult to remove this solidified foamed mixture. 
     The present invention was developed in view of the above problems, and it is an object of the present invention to provide a mold forming apparatus capable of accurately forming a mold by reliably causing a foamed mixture to appropriately fill a cavity of a forming mold by a simple configuration, and capable of achieving reduction in size. 
     Means for Solving the Problem 
     In order to achieve the above object, the invention according to a mold forming apparatus of claim  1  is a mold forming apparatus including a storage tank that has in its bottom a plurality of injection ports capable of being opened and closed, and that stores a foamed mixture formed by agitating a granular aggregate and an additive, a forming mold that has a plurality of runners into which the foamed mixture is introduced through their inlets formed so as to correspond to the respective injection ports of the storage tank, and that has a cavity for forming the introduced foamed mixture into a mold with a predetermined shape, and pressing means that is disposed so as to correspond to the forming mold and that presses the foamed mixture stored in the storage tank to inject the foamed mixture into the cavity through the runners of the forming mold, characterized in that a parting surface of the forming mold is formed parallel to a pressing direction of the pressing means, and each of the runners of the forming mold is formed in the parting surface and is tilted with respect to the pressing direction of the pressing means so as to spread apart from the inlet toward its outlet guided to the cavity. 
     In order to achieve the above object, in the invention of claim  1 , the invention of the mold forming apparatus of claim  2  is characterized in that the runners extend from the inlets and branch off in an intermediate portion on a downstream side being allowed to obtain the plurality of outlets guided to the cavities. 
     Effects of the Invention 
     According to the invention of claim  1 , the parting surface of the forming mold is formed parallel to the pressing direction of the pressing means, and each of the runners of the forming mold is fowled in the parting surface of the forming mold and is tilted with respect to the pressing direction of the pressing means so as to spread apart from other runners from the inlet toward its outlet to the cavity. With this simple configuration, the bottom of the storage tank can be made smaller than the maximum width of the surface of the forming mold in which the inlets of the runners are formed. The storage tank therefore need not have a size according to the size of the forming mold, and can thus be reduced in size. Moreover, the forming mold does not interfere with the pressing means when opened. The mold forming apparatus can thus be reduced in size. 
     Since the runners are formed in the parting surface of the forming mold, any solidified foamed mixture remaining inside the runners can be easily removed by opening the forming mold. 
     According to the invention of claim  2 , the runners extend from the inlets and branch off in an intermediate portion on the downstream side, and have the plurality of the outlets, which guide to the cavities. The inlets of the runners therefore need not be formed so as to correspond to the number of cavities, and the foamed mixture can be reliably caused to appropriately fill the cavities of the forming mold. 
     (Exemplary Forms of the Invention) Some forms of the invention that is recognized as being able to be claimed in the present application (hereinafter sometimes referred to as the “invention that can be claimed”; the invention that can be claimed includes at least the “invention” or “present invention” that is the invention described in the claims, but may include an invention having a narrower concept than the present invention or an invention having a broader concept or a different concept than the present invention) will be shown and described below. As in the claims, the forms are divided into items, the items are numbered, and the number(s) of other item(s) is cited as necessary. This is merely for facilitating understanding of the invention that can be claimed, and is not intended to limit the combination of constituent elements forming the invention that can be claimed to the combinations described in the items shown below. That is, the invention that can be claimed should be interpreted in view of the description associated with each item, the description of the embodiment, etc., and any fowl in which other constituent element(s) is added to the form of each item or any form in which the constituent element(s) is eliminated from the form of each item may be one form of the invention that can be claimed, as long as these forms are consistent with the interpretation. In the following items, items (1), (2) correspond to claims  1 ,  2 , respectively. 
     ( 1 ) A mold forming apparatus including
         a storage tank that has in its bottom a plurality of injection ports capable of being opened and closed, and that stores a foamed mixture formed by agitating a granular aggregate and an additive;   a forming mold that has a plurality of runners into which the foamed mixture is introduced through their inlets formed so as to correspond to the respective injection ports of the storage tank, and that has a cavity for forming the introduced foamed mixture into a mold with a predetermined shape; and   pressing means that is disposed so as to correspond to the forming mold and that presses the foamed mixture stored in the storage tank to inject the foamed mixture into the cavity through the runners of the forming mold, characterized in that   a parting surface of the forming mold is formed parallel to a pressing direction of the pressing means, and   each of the runners of the forming mold is formed in the parting surface and is tilted with respect to the pressing direction of the pressing means so as to spread apart from the inlet toward its outlet guided to the cavity.       

     (2) The mold forming apparatus according to item (1), characterized in that the runners extend from the inlets and branch off in an intermediate portion on a downstream side being allowed to obtain the plurality of the outlets guided to the cavity. 
     (3) The mold forming apparatus according to item (1) or (2), characterized in that an area of the bottom of the storage tank is 70% to 30% of that of a surface of the forming mold in which the inlets of the runners are formed. 
     Setting the area of the bottom of the tank to 70% to 30%, more preferably 50% to 30%, of that of the surface of the forming mold in which the inlets of the runners are formed makes it possible to make the diameter of the bottom of the cylindrical storage tank smaller than a maximum width of the surface of the forming mold in which the inlets of the runners are formed. 
     (4) The mold fanning apparatus according to any one of items (1) to (3), characterized in that the storage tank is formed in a cylindrical shape and the bottom has a diameter smaller than a maximum width of the surface of the forming mold in which the inlets of the runners are formed. 
     Making the diameter of the bottom of the cylindrical storage tank smaller than the maximum width of the surface of the forming mold in which the inlets of the runners are formed makes it possible to make the bottom of the storage tank smaller than the maximum width of the surface of the forming mold in which the inlets of the runners are formed. 
     (5) The mold forming apparatus according to any one of items (1) to (4), characterized by further including agitating means including an agitating member that rotates inside the storage tank to agitate the granular aggregate and the additive, which have been put in the storage tank, to form the foamed mixture. 
     With the agitating means, the storage tank can function both as an agitation tank in which the granular aggregate and the additive are agitated and as an injection cylinder that injects the foamed mixture stored therein into the forming mold. 
     (6) The mold forming apparatus according to item (5), characterized by further including moving means for relatively moving the storage tank and the agitating member between an agitating position where the agitating member is located inside the storage tank and a withdrawn position where the agitating member is located outside the storage tank and for relatively moving the storage tank between the withdrawn position and a position between the forming mold and the pressing means where the injection ports are connected to the inlets of the runners of the forming mold. 
     After the granular aggregate and the additive which have been put in the storage tank are agitated by the agitating member to form the foamed mixture, the agitating member is immediately moved relative to the storage tank to the withdrawn position by the moving means, and the storage tank is relatively moved to the position between the forming mold and the pressing means to connect the injection ports to the inlets of the runners of the forming mold. The cavities of the forming mold can thus be reliably and quickly filled with the foamed mixture in a satisfactory state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic front view illustrating an embodiment of an entire mold forming apparatus of the present invention. 
         FIG. 2  is a plan view illustrating a storage tank and a forming mold of the present invention. 
         FIG. 3  is a front view of  FIG. 2 . 
     
    
    
     MODES FOR CARRYING OUT THE INVENTION 
     An embodiment of a mold forming apparatus of the present invention will be described in detail based on  FIGS. 1 to 3 . The same reference numerals and characters are used throughout the figures to denote similar or corresponding portions. 
     The mold forming apparatus of the present invention generally includes: a storage tank  1  that has in its bottom  1   a  a plurality of injection ports  10  capable of being opened and closed, and that stores a foamed mixture formed by agitating a granular aggregate and an additive; a forming mold  2  that has a plurality of runners  20  into which the foamed mixture is introduced through their inlets  20   a  fanned so as to correspond to the respective injection ports  10  of the storage tank  1 , and that has cavities  21  for forming the introduced foamed mixture into a mold with a predetermined shape; and pressing means  3  that is disposed so as to correspond to the forming mold  2  and that presses the foamed mixture stored in the storage tank  1  to inject the foamed mixture into the cavities  21  through the runners  20  of the forming mold  2 . A parting surface  22  of the forming mold  2  is formed parallel to a pressing direction P of the pressing means  3 . Each of the runners  20  of the forming mold  2  is formed in the parting surface  22  and is tilted with respect to the pressing direction P of the pressing means  3  so as to spread apart from other runners in a direction from the inlet toward its outlet guided to the cavity. 
     In the mold forming apparatus of the present invention, the runners  20  extend from the inlets  20   a  and branch off in an intermediate portion on a downstream side being allowed to obtain the plurality of the outlets  20   b  guided to the cavities  21 . 
     In the mold forming apparatus of the present embodiment, the storage tank  1  is formed in a cylindrical shape (hereinafter referred to as the “cylindrical tank  1 ”), and the bottom  1   a  has a diameter D smaller than the maximum width W of a surface  2   a  of the forming mold  2  in which the inlets  20   a  of the runners  20  are formed. The mold forming apparatus of the present embodiment further includes agitating means  4  including an agitating member  40  that rotates inside the cylindrical tank  1  to agitate the granular aggregate and the additive, which have been put in the cylindrical tank  1 , to form the foamed mixture. The mold forming apparatus of the present embodiment further includes moving means (described later) for relatively moving the cylindrical tank  1  and the agitating member  40  between an agitating position where the agitating member  40  is located inside the cylindrical tank  1  and a withdrawn position where the agitating member  40  is located outside the cylindrical tank  1  and for relatively moving the cylindrical tank  1  between the withdrawn position and a position between the forming mold  2  and the pressing means  3  where the injection ports  10  are connected to the inlets  20   a  of the runners  20  of the forming mold  2 . 
     The cylindrical tank  1  is open in its upper part and has the plurality of injection ports  10  in the bottom  1   a . The bottom  1   a  therefore has a circular shape as shown in  FIG. 2 . The bottom  1   a  is provided with opening/closing means such as a plug member or a shutter which controllably opens and closes the injection ports  10 . 
     In the present embodiment, the forming mold  2  is formed by a pair of forming molds  2 A,  2 B so that the parting surface  22  of the forming molds  2 A,  2 B extends vertically. The forming molds  2 A,  2 B are therefore opened and closed along the vertical direction on the paper of  FIG. 2  showing a plan view. The runners  20  for introducing the foamed mixture and the cavities  21  for forming a mold with a predetermined shape are formed in abutting surfaces of the forming molds  2 A,  2 B. In the present embodiment, the inlets  20   a  of the runners  20  are open at the upper surface of the forming mold  2  in  FIG. 3 . The inlets  20   a  of the runners  20  are disposed so as to be aligned with the injection ports  10  when the cylindrical tank  1  is located on the surface  2   a  of the forming mold  2  in which the inlets  20   a  of the runners  20  are formed. In the embodiment shown in  FIG. 3 , the runners  20  are formed such that small parts of their upstream portions which extend from the inlets  20   a  to be connected to the injection ports  10  are parallel to the pressing direction P of the pressing means  3 . The runners  20  are bent at an intermediate position, and their intermediate portions forming large parts of the runners  20  are tilted with respect to the pressing direction P of the pressing means  3  so as to spread apart from each other. In the present embodiment, each of the runners  20  branches into two in its downstream portion, and the outlets  20   b  are respectively open to a plurality of the cavities  21  via a core print part  23  provided in the forming mold  2 . The angle at which the runners  20  are tilted with respect to the pressing direction P of the pressing means  3  can be set as appropriate in view of the shape and size of a mold to be formed, the positions of the cavities  21  that are formed in the forming mold  2 , fluidity of the foamed mixture, etc. 
     In the present embodiment, the pressing means  3  has a cylinder  30  provided above the forming mold  2 , and a piston  31  fittingly inserted in the cylinder  30  and provided with a pressing portion  31   a  that enters the cylindrical tank  1  through an opening in the upper part of the cylindrical tank  1  to press the foamed mixture. In the present embodiment, the pressing direction P of the pressing means  3  is downward in the vertical direction in  FIG. 3 . With the bottom  1   a  of the cylindrical tank  1  being placed on the upper surface  2   a  of the forming mold  2  such that the injection ports  10  are aligned with the inlets  20   a  of the runners  20  and are opened, the piston  31  in the cylinder  30  is driven to extend. The pressing portion  31   a  at the tip end of the piston  31  can thus enter the cylindrical tank  1  through the opening in the upper part of the cylindrical tank  1  and press the foamed mixture to inject the foamed mixture through the injection ports  10  to fill the cavities  21  with the foamed mixture through the runners  20  of the forming mold  2 . That is, the cylindrical tank  1  functions as an injection cylinder that injects the foamed mixture stored therein to fill the cavities  21  of the forming mold  2  with the foamed mixture. The parting surface  22  of the forming molds  2 A,  2 B extends vertically, and the forming molds  2 A,  2 B are opened and closed along the lateral direction or in the front-back direction in the plane of the paper of  FIG. 3 . As described below, the cylinder  30  can therefore be disposed at about such a height that, with the piston  31  in the cylinder  30  being in a retracted state, the pressing portion  31   a  does not interfere with the cylindrical tank  1  when the cylindrical tank  1  is moved to the left from the withdrawn position of agitating blades  40   a  as indicated by an arrow S in  FIG. 1 . 
     In the present embodiment, the agitating member  40  of the agitating means  4  has a plurality of agitating blades  40   a  around a rotary shaft  40   b.  The rotary shaft  40   b  for the agitating blades  40   a  is connected to a rotary drive shaft of a motor  41 . The motor  41  is supported by a support member  42 . With the injection ports  10  of the cylindrical tank  1  being closed, the granular aggregate and the additive are put in the cylindrical tank  1 . The agitating blades  40   a  are moved into the cylindrical tank  1 , and the motor  41  is driven to rotate, whereby the granular aggregate and the additive can be agitated to form the foamed mixture in the cylindrical tank  1 . That is, the cylindrical tank  1  can function not only as the injection cylinder described above but also as an agitation tank in which the granular aggregate and the additive are agitated to form the foamed mixture. In the present invention, since the diameter D of the bottom  1   a  of the cylindrical tank  1  is smaller than the maximum width W of the surface  2   a  of the forming mold  2  in which the inlets  20   a  of the runners  20  are formed, the agitating blades  40   a  can also be reduced in size. The load on the motor  41  that drivingly rotates the agitating blades  40   a  is therefore reduced accordingly, whereby the motor  41  can also be reduced in size. 
     In the present embodiment, the moving means includes: agitating blade moving means  5  that moves the agitating blades  40   a  of the agitating means  4  between the agitating position where the agitating blades  40   a  having been moved into the cylindrical tank  1  through the opening in the upper part of the cylindrical tank  1  can agitate the granular aggregate and the additive, and the withdrawn position where the agitating blades  40   a  are withdrawn out of the cylindrical tank  1  through the opening in the upper part of the cylindrical tank  1  (see an arrow V in  FIG. 1 ); and moving the cylindrical tank  1  to the position between the pressing portion  31   a  and the forming mold  2  with the agitating blades  40   a  being located at the withdrawn position and the piston  31  of the pressing means  3  being in the retracted state (see the arrow S in FIG,  1 ). In the present embodiment, the agitating blade moving means  5  includes a cylinder  50  disposed at a predetermined height and having the support member  42  bonded to the tip end of a piston rod  51 . In the present embodiment, after the granular aggregate and the additive which have been put in the cylindrical tank  1  are agitated by the agitating blades  40   a  to form the foamed mixture, the piston rod  51  of the cylinder  50  is immediately driven to retract so that the agitating blades  40   a  are moved to withdraw, and the cylindrical tank  1  is moved in the direction indicated by the arrow S in  FIG. 1  to the position between the upper surface  2   a  of the forming mold  2  and the pressing portion  31   a  of the pressing means  3 . The bottom  1   a  is placed on the upper surface  2   a  of the forming mold  2  such that the injection ports  10  are aligned with the inlets  20   a  of the runners  20 . The cavities  21  of the forming mold  2  are thus filled with the foamed mixture in a satisfactory state, and a mold having satisfactory shape accuracy etc. can be formed. 
     The outlets  20   b  of the runners  20  which open to the cavities  21  in the forming mold  2  are disposed according to the size or shape of a mold to be formed. The runners  20  are formed in the parting surface  22  of the forming mold  2  and are tilted with respect to the pressing direction P of the pressing means  3  so as to spread apart from each other from the inlets  20   a  toward the outlets  20   b.  The inlets  20   a  of the runners  20  are formed in the upper surface  2   a  of the forming mold  2  which is to be contacted by the cylindrical tank  1 , and are open to the parting surface  22  of the forming molds  2 A,  2 B. 
     The injection ports  10  of the cylindrical tank  1  are disposed in the bottom  1   a  such that the injection ports  10  can be aligned with the inlets  20   a  of the runners  20  so as to communicate with the inlets  20   a  of the runners  20 . The cylindrical tank  1  is therefore formed such that its diameter D is smaller than the maximum width W of the forming mold  2 . The diameter D of the cylindrical tank  1  can be set such that the area of the bottom  1   a  is 70% to 30%, more preferably 50% to 30%, of that of the upper surface  2   a  of the forming mold  2  in which the inlets  20   a  of the runners  20  are open. This can reliably make the bottom  1   a  of the cylindrical tank  1  smaller than the maximum width W of the upper surface  2   a  of the forming mold  2  in which the inlets  20   a  of the runners  20  are formed. The mold forming apparatus can therefore be reduced in size. Since the parting surface  22  of the forming mold  2  is parallel to the pressing direction P of the pressing means  3 , the pressing means  3  does not interfere with the forming mold  2  when the forming mold is opened. The mold forming apparatus can therefore be reduced in size. Any solidified foamed mixture remaining in the runners  20  can be easily removed by opening the forming mold  2 . 
     The present invention is not limited to the above embodiment in which the bottom  1   a  of the cylindrical tank  1  is positioned on the lower side in the figure and the pressing means  3  presses the foamed mixture from above. For example, the present invention may include a configuration in which the bottom  1   a  of the cylindrical tank  1  is disposed laterally, the forming mold  2  is disposed laterally on the bottom  1   a  of the cylindrical tank  1 , and the pressing means  3  laterally presses the foamed mixture to fill the cavities of the forming mold  2  with the foamed mixture. The present invention may also include a configuration in which the bottom  1   a  of the cylindrical tank  1  is positioned on the upper side upward, the forming mold  2  is disposed on the bottom  1   a  of the cylindrical tank  1 , and the pressing means  3  presses the foamed mixture from below to fill the cavities of the forming mold  2  with the foamed mixture, etc. 
     The present invention can be applied to any apparatus that forms a mold in a predetermined shape by storing in a storage tank a foamed mixture formed by agitating a granular aggregate and an additive, and pressing the foamed mixture by pressing means to inject the foamed mixture from the storage tank through an injection port to fill a cavity with the foamed mixture through a runner of a forming mold. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
     
         
           1 : Cylindrical Tank (Storage Tank) 
           1   a : Bottom 
           2 : Forming Mold 
           3 : Pressing Means 
           4 : Agitating Means 
           10 : Injection Port 
           20 : Runner 
           20   a : Inlet 
           20   b : Outlet 
           21 : Cavity 
           22 : Parting Surface 
           40 : Agitating Member 
         D: Diameter of Cylindrical Tank 
         W: Maximum Width of Forming Mold