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US 2008/0257515 A1Published application
Pre-Tensioned Sand Core
OwnerMartin Zoldaninventor
Life of this patent
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Abstract
Provided are methods of replacing drilling holes in castings by pre-tensioning sand cores. This methods are used in long cylindrical shaped sand cores in cold core box processes. The urethane sand core is placed in compression to increase the core strength during handling, placing inside of the mold. The pre-tensioned urethane sand core is set in a casting mold so as to form a cavity in the casting mold. The molten metal is poured to form the cavity inside of the casting. The pre-tensioned urethane sand core maintains its initial shape during casting.
Claims20
A method of making a sand core, the method comprising
- applying tension to a wire within the yield point by pulling the ends of a wire away from each other;
- applying a sand-binder mixture around the wire to form a predetermined shape;
- allowing the sand-binder mixture to harden;
- and
- releasing the tension to the wire.
2 more elements
6-9. (canceled)
Dependencies are inferred from the claim text.