Patent ID: 8151861

Claim:
A method for making a one-piece core for a railway truck bolster or a railway truck side frame, wherein the one-piece core is the only core used to form the entire railway truck bolster or railway truck side frame, the method comprising the steps of: placing reinforced core bars and movable pieces into a one-piece core box cavity; overfilling the core box cavity with sand; tamping or jolt-ramming the sand; scraping off sand residue so that a height of the sand is at a same height as a top surface of the core box; when the core sand firmness is sufficient, and using an upper press mould having a curved inner cavity shape, pressing the empty upper press mould down on the sand in the core box by using a guidance action, a slight hit, or by pressing the upper press mould to connect the upper press mould to the scraped-off surface; continuing to press down the upper press mould to make a base surface of the upper press mould adhere closely to the top surface of the core box; after adhering the base surface, making the core sand firmer; overturning the upper press mould and the core box; lifting the core box while a formed sand core is enclosed by the movable pieces and the movable pieces are disposed on the base surface of the upper press mould; sliding the movable pieces along the base surface to remove the movable pieces from the sand core; after removing the movable pieces, supporting the sand core on the base surface while hardening the sand core; and cleaning the sand core after it is hardened to a required firmness.