| 摘要 |
The removal of a deep bore pattern (14) from a sand mold is facilitated by exerting a force on the sand (12) within the bore (16) to break the bond between the sand and the internal surface of the pattern. The pattern (14) is supported on a pattern plate (18) having an aperture (20) in line with the bore (16). A stripper block (22) is slidably received in the aperture and can extend into the bore. A fixed back plate (24) is supported on the pattern plate, and a compression spring (26) is positioned between the stripper block (22) and the back plate (24). As sand is packed into the mold, and hence the bore, under pressure, the stripper block is forced out of the bore against the spring. When the pressure is removed to allow the pattern to be withdrawn, the spring exerts a force on the stripper block causing it to move back to its initial position, thus breaking the sand free from the inside surface of the deep bore. |
