Screw

• US 3,313,197 A
• Filed: 09/08/1965
• Issued: 04/11/1967
• Est. Priority Date: 09/08/1965
• Status: Expired due to Term

• Current Assignee: Karl Knohl Friedrich
• Original Assignee: Karl Knohl Friedrich
• Inventors: KARL KNOHL FRIEDRICH
• Application Number:
  US04/485,782
• Time in Patent Office: 580 Days
• US Class Current: 411/387.1
• CPC Class Codes: F16B 35/06 Specially-shaped heads special shape in order to rotate the bolt F16B23/00 ; separate hook adaptors for bolts F16B43/025

Claims

1. A FASTENER COMPRISING A THREADED SHANK HAVING AT ONE END A CUTTING EDGE MEANS FOR DRILLING AN APERTURE, SAID SHANK AT ITS OPPOSITE END HAVING A TAPERED, UNTHREADED NECK FLARING RADIALLY OUTWARDLY FROM SAID SHANK AND TERMINATING IN A HEAD HAVING A LOWER PORTION AND AN UPPER PORTION, SAID LOWER PORTION HAVING A CLAMPING SURFACE NORMAL TO SAID SHANK AND PROVIDING A JUNCTURE WITH SAID TAPERED NECK, SAID LOWER PORTION FURTHER HAVING A PERIPHERY FLARING RADIALLY OUTWARDLY FROM SAID CLAMPING SURFACE AT AN INCLUDED ANGLE OF FROM 80* TO 100*, SAID UPPER PORTION HAVING A TOP CURVILINEAR SURFACE, THE COMBINED HEIGHT OF SAID LOWER AND UPPER PORTIONS BEING LESS THAN 2/3 THE DIAMETER OF SAID SHANK AND THE DIAMETER OF SAID HEAD BEING AT LEAST TWO AND ONE-HALF TIMES THE DIAMETER OF SAID SHANK, SAID TAPERED NECK HAVING AN INCLUDED ANGLE OF FROM 40* TO 55* AND HAVING A HEIGHT MEASURED ALONG THE AXIS OF SAID SHANK SUBSTANTIALLY EQUAL TO THE COMBINED AXIAL HEIGHT OF SAID LOWER AND UPPER PORTIONS OF SAID HEAD, SAID HEAD BEING CONTINUOUS ABOUT ITS PERIPHERY AND BEING PROVIDED WITH A RECESS IN SAID UPPER PORTION FOR ENGAGEMENT WITH A DRIVING TOOL.