BOLTING FOR MINE WORKING AND METHOD OF ITS MANUFACTURING Russian patent published in 2008 - IPC E21D21/00 B23G1/00 

FIELD: mining.

SUBSTANCE: bolting for mine workings includes reinforcing rod made of spiral profile rolled stock, salient bearing plate, hexagonal nut with head in the form of hollow ball layer and limiter in the form of conic ring with inner diameter equal to rod nominal diameter made of spiral profile rolled stock providing nut barring on bolt shaft at bracing ampule contain mixing in well. Hollow ball layer can be outfitted by circular bearing flange. Manufacturing method of bolting includes fittings cutting from rolled stock of spiral and round profiles for cutoffs of cut length, carving and punching of prominent back-up plate, upset forging and molding of nut blank with hole cutting, screw in it cutting of coarse pitch spiral profile at nut blank rotation, fixed in turning machine chuck and drawing through it tap-broach, fixed in lathe support holder. Screw cutting of coarse pitch spiral profile is made by broaching method with instrument forcing right to left, at that rotating nut blank is fixed in work-holding device by means of hexahedron and bearing flange without additional clipping. Spigot on nut face in the frustaconical shape form at nut blank upset forging with its further transformation into conic ring by means of punching. Carving on nut conic ring is formed by rod transversal lug knurl method located by single spiral at the rotation process of nut after bolt shaft fixing inside of well with bracing composition.

EFFECT: invention allows to prevent nut spontaneous turn off and improve productivity of screw cutting.

5 cl, 4 dwg