Blow molding machine

Abstract

A blow molding machine provided with a blow head to hold molding sand therein, at least one passage connected to an upper portion of the blow head at one end thereof and connected to a pressurized air supply source at the other end so as to apply compressed air to the molding sand held in the blow head, for blowing and charging the molding sand from the blow head into a mold space that is located adjacent the blow head and then compacting the charged molding sand to produce a sand mold. The blow molding machine includes at least one chamber disposed on an inner surface of an external wall of the blow head at a middle portion of the blow head, the chamber having an inner surface facing the molding sand held in the blow head, at least part of the inner surface having a plurality of apertures to allow air to pass through them, and a pressurized air supply source connected to the chamber to supply compressed air into the chamber and into the molding sand to fluidize it.

What we claim is:  
     
         1 . A blow molding machine provided with a blow head to hold molding sand therein, at least one passage connected to an upper portion of the blow head at one end thereof and connected to a pressurized air supply source at the other end so as to send compressed air to the molding sand held in the blow head, for blowing and charging the molding sand from the blow head into a mold space that is located adjacent the blow head and then compacting the charged molding sand to produce a sand mold, comprising: 
 at least one chamber disposed on an inner surface of an external wall of the blow head at a middle portion of the blow head, the chamber having an inner surface facing the molding sand held in the blow head, at least part of the inner surface having a plurality of apertures to allow air to pass through the apertures, and    a pressurized air supply source connected to the at least one chamber to supply compressed air into the chamber and into the molding sand, thereby fluidizing the molding sand.    
     
     
         2 . The blow molding machine of    claim 1   , wherein the pressurized air supply source connected to the upper portion of the blow head is the pressurized air supply source that is connected to the at least one chamber.  
     
     
         3 . The blow molding machine of    claim 1    or    2   , comprising a plurality of juxtaposed passages connected to the upper portion of the blow head, the passages being selectively opened and closed.  
     
     
         4 . The blow molding machine of    claim 1   ,    2   , or  3 , wherein the at least one chamber is at least one chamber that extends around the periphery of the inner surface of the external wall of the blow head.