Harvey J. Harwood, "Improved screw machine," U.S. Patent no. 65,567 (issued: June 11, 1867). In his patent, Harwood states: "In the manufacture of wood-screws the thread has been formed hitherto by removing the metal between the turns of the thread by means of dies or cutters. By my invention the blank is rotated between rotating or reciprocating dies, suitably formed, and set in motion, by means of which the thread is impressed on the blank without removing any part of the metal."
Apparently Harwood and the patent examiner were ignorant of Keane's 1836 patent.
Harvey J. Harwood, "Improved screw machine," U.S. Patent no. 65,567 (issued: June 11, 1867). In his patent, Harwood states: "In the manufacture of wood-screws the thread has been formed hitherto by removing the metal between the turns of the thread by means of dies or cutters. By my invention the blank is rotated between rotating or reciprocating dies, suitably formed, and set in motion, by means of which the thread is impressed on the blank without removing any part of the metal."
Apparently Harwood and the patent examiner were ignorant of Keane's 1836 patent.
Harvey J. Harwood, "Improved screw machine," U.S. Patent no. 65,567 (issued: June 11, 1867). In his patent, Harwood states: "In the manufacture of wood-screws the thread has been formed hitherto by removing the metal between the turns of the thread by means of dies or cutters. By my invention the blank is rotated between rotating or reciprocating dies, suitably formed, and set in motion, by means of which the thread is impressed on the blank without removing any part of the metal."
Apparently Harwood and the patent examiner were ignorant of Keane's 1836 patent.