METHOD FOR MANUFACTURING CORRUGATED SCREW BLANKS

摘要

A method for manufacturing corrugated screw blanks, in which first U-shaped depressions are formed on a tape at an angle to the longitudinal axis to form a corrugated tape, and then forming a corrugated spiral is carried out followed by its stretching for a pitch. Forming the corrugated spiral is performed by compression of the corrugated tape on the edge by upper and lower rolls. The upper roll is positioned from the side of outer edge of corrugated tape relative to the center of curvature of the corrugated spiral and linear speed of rotation of its surface at the point of interaction with the corrugated tape is higher than the speed of feed of the corrugated tape. The lower roll is located from the side of inner edge relative to the center of curvature of corrugated spiral with a shift relative to the upper roll opposite to the direction of feed of the corrugated tape. The linear speed of rotation of its surface at the point of interaction with the corrugated tape is less than the speed and opposite to the feeding direction of such tape.