Jointed support system and method of constructing same

摘要

The invention provides a method of injection molding a part having an undercut region and a method of assembling a jointed structure from several parts. A two-part mold has a common cavity with part of the cavity in each mold part. A combined pin-in-a-sleeve extends into the cavity in one of the mold parts in order to form a bore in a part to be molded in that cavity. The pin provides a portion shaped to form a first undercut region in the bore. A second pin extends into the cavity in the other of the two mold parts. The two pins are aligned to form a single bore in the molded part while in the cavity. The second pin also has a portion shaped to form a second undercut region in the bore. After an injection molded part is made, the mold opens a limited and discrete distance to allow the molded part to be released from the hold of the mold cavity. Then, the mold opens fully for the continuation of a multi-step operation to pull the pins out of the undercut regions.