| 摘要 |
A collapsible mold core comprises an inner core member, which remains out of contact with the inside peripheral surface of the molding, first and second pairs of mutually opposite, outer core members, which engage the molding and determine the shape thereof, and guides which converge toward the axis of the core and serve to guide the pairs of outer core members parallel to guide planes which are offset 90 DEG from each other and extend through the axis of the core. The four outer core members tightly adjoin each other, and the outer core members of the first pair have lateral wedge faces which extend parallel to the guides and at right angles to the guide plane of the outer core members of the second pair. The latter have inclined surfaces which are disposed on the side which faces the axis and are parallel to the wedge faces of the other outer core members, and the outer core members of both pairs are adapted to be displaced from a molding position in that longitudinal direction of the guides in which the latter converge. The displacement of the outer core members of the first pair is smaller than the displacement of the outer core members of the second pair.
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