| 摘要 |
PURPOSE:To mold a core having uniform strength by arranging a lower core box and a frame-like banking core box as liftable and arranging a sliding core box as sliding-liftable to side part of a fixed upper core box at the upper part thereof as projecting to lower part from the lower face of fixed upper core box at the lower end thereof, to fill and compress the green sand. CONSTITUTION:Under condition of pushing down the sliding core box 18 by extending a cylinder 20, the lower core box 9 and the banking core box 14 are ascended by extending a cylinder 1 through a table 4. And, lower end part of the sliding core box 18 is fitted into hollow part 13 in the banking core box 14, which is stopped to the position coinciding a blowing hole 12 with a blowing hole 24 of the blowing plate 23. By this method, a pre-forming cavity, in which the shape of upper half part is enlarged toward vertical direction by the lower core box 9, banking core box 14, sliding core box 18 and the fixed upper core box 16, is shaped. Next, by blowing green sand 27 into the preforming cavity is molded. Successively, after making the cylinder 20 freely, by further extending the cylinder 1, the lower core box 9 and banking core box 10 are ascended to the position, where the banking core box 14 is abutted on a stopper 21, and by compressing the preforming body, the green sand core is molded.
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