Method and apparatus for compacting molding sand

#This intention relates to a method and an apparatus for compacting molding sand.

#In one conventional method of compacting molding sand that has been charged into a mold space defined by a pattern plate and a flask, means for compacting the molding sand and the pattern plate are moved relative to each other. In this method a molding machine requires a large hydraulic cylinder for vertically moving the pattern plate, and hence has a high profile. This produces a problem in that, for example, a pit must be provided in a floor when the machine is installed on it. Further, separating a produced sandmold from the pattern plate cannot be done stably. Thus it is difficult to make smaller the draft of the sandmold. A great draft would make a sandmold heavy. Certainly, this is not preferable. Further, even when the properties of the molding sand are changed, the conditions for the compaction cannot be readily changed.

#This invention has been conceived in view of the drawbacks discussed above. It is a purpose of the invention to provide a method that does not require a large hydraulic cylinder for vertically moving a pattern plate, which requires a pit, and that can compact almost all of the molding sand, which has been charged into a mold space defined by a flask and a pattern plate, to a desired degree.

#FIG. 1 is a schematic cross-sectional view of a molding machine used to implement the method of the present invention.

#FIG. 2 is a schematic cross-sectional view of another molding machine used to implement the method of the present invention, showing the figure of the machine before it starts operating.

#FIG. 3 is a view of the molding machine in FIG. 2, showing a mold space being defined.

#The first embodiment of a molding machine that implements the present invention is now explained by reference to FIG. 1. The molding machine comprises a pattern plate 1, which is fixed in a horizontal position, a leveling frame 2 disposed for vertical sliding movement around the outer periphery of the pattern plate 1., a flask 3, as a frame member, disposed for vertical movement above the leveling frame 2, a filling frame 4 disposed for vertical movement above the flask 3, and compacting means 5 having a lower part that can enter the filling frame 4.

#The pattern plate 1, which includes a pattern, is secured to the top of a pattern plate carrier 19a of a pattern plate changer 19 (below explained). If necessary, the pattern plate 1 may be provided with vent holes (not shown) embedded in its top surface, depending on the shape of the pattern. The leveling frame 2 is embedded in the pattern plate carrier 19a such that it is vertically moved by a plurality of hydraulic cylinders 6, which are also embedded in the pattern plate carrier 19a at positions under the leveling frame to act as a means for vertically moving the leveling frame. The flask 3 is transferred by a transfer mechanism 9 forward and backward (in the direction perpendicular to the sheet of the drawing) The transfer mechanism 9 consists of collar rollers 7, 7 spaced apart in forward and backward directions and mounted on frames 8, 8, which are, in turn, suspended from a frame 10 that moves vertically. The vertically-movable frame 10 bridges the upper (distal) ends of the piston rods of two upwardly-facing hydraulic cylinders 12, 13, which, in turn, are mounted on a base or a surface plate 11 of the molding machine near the right and left sides of the surface plate 11, so that the frame 10 is vertically moved by the cylinders 12, 13.

#The filling frame 4 is suspended from the piston rods of the downwardly-facing hydraulic cylinders 14, 14, which are, in turn, mounted on the frames 8, 8. Rails 20, 20 are secured to the frames 8, 8. The compacting means 5 is mounted on the rails 20, 20 through collar rollers 21, 21 so that it can move forward and backward. The compacting means has a plurality of compacting members 18, each of which is shaped as a parallelepiped, and which are vertically movable. Further, a sand hopper (not shown) for metering an amount of molding sand and for running forward and backward, is mounted on the rails 20, 20. Further, the pattern plate changer 19 is rotatably mounted at its middle portion on one of the two upwardly-facing cylinders 12, 13 (in the example shown in the drawing, on the left cylinder 12). The pattern plate changer 19 has another pattern plate carrier 19b at one end, which is opposite the other end at which the pattern plate carrier 19a is supported. The pattern plate carrier 19b carries another pattern plate 1a. A leveling frame 2 and hydraulic cylinders 6, for vertically moving the leveling frame, are also embedded in the pattern plate carrier 19b just the same as in the pattern plate carrier 19a.