METHOD OF MANUFACTURING WRITING CHALK Russian patent published in 2002 - IPC

FIELD: household chemical goods. SUBSTANCE: writing chalk are manufactured by pouring elastic materials into molds. Casting mold is constructed in the form of flexible sheet, in which casting cells corresponding to finished chalks in shape and size are made. Cells are filled with chalk paste at horizontal position of sheet mold and hold until hardening, after which sheet is overturned and bent by convexity in direction of cells. The latter are manufactured with a small falling-out of walls thereby forming, in transversal and longitudinal cross-sections, trapezes with base length difference no more than 2 mm. EFFECT: facilitated pouring into molds and dislodging of hardened chalks. 2 ex