LAWRENCE DANIEL JOHNSON
Pilots at Dallas Rd, Rockford, IL
License number
Illinois A0954256
Issued Date
Sep 2015
Expiration Date
Sep 2017
Category
Airmen
Type
Authorized Aircraft Instructor
Address
Address
3404 Dallas Rd, Rockford, IL 61109
Professional information
Self-Tapping Or Thread-Forming Screw
US Patent:
4104446, Aug 1, 1978
Filed:
Sep 14, 1976
Appl. No.:
5/723329
Inventors:
Lawrence D. Johnson - Rockford IL
Assignee:
Keystone Consolidated Industries, Inc. - Peoria IL
International Classification:
B21H 302, B21H 310
US Classification:
428585
Abstract:
An improved self-tapping or thread-forming screw where the thread configuration on the screw end swages or forms the thread in an object to be threaded rather than cutting and removing a portion of the material of the object. The screw is provided with a threaded shank terminating in a tapered thread-forming end having four equi-spaced flattened surfaces separated by four threaded lobes or corners, and each corner is provided with a leading flattened surface in place of a portion of the radius to provide a partially threaded relief area in addition to the full relief areas formed by the flattened sides.