| 摘要 |
Disclosed herein is a die member for forming a lost foam pattern for casting a cylinder block having a cylindrical bore with an axis and a helical transfer passage including a first portion permitting die member separation in a direction along the axis of the cylindrical bore and a second undercut portion preventing one-piece die member separation in the direction along the axis of the cylindrical bore, which die member comprises a projection forming a first cavity corresponding to a first part of the first portion of the transfer passage, and a core carried by the die member and movable relative to the die member between an extended position forming a second cavity corresponding to a second part of the first portion of the transfer passage and the undercut portion of the transfer passage, and a retracted position affording separation of said core through the second part of the first portion of the transfer passage and in common with separation of said projection from the first portion of the transfer passage in the direction along the axis of the cylindrical bore.
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