The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 22, 1997
Filed:
Aug. 22, 1995
Michael C Dill, Elk Grove Village, IL (US);
James W McElderry, Schaumburg, IL (US);
Juergen O Rathgeber, Arlington Heights, IL (US);
Illinois Tool Works Inc., Glenview, IL (US);
Abstract
A screw for use with a washer as a sealing fastener having formations near the head of the screw to increase driving resistance when the portion having the formations reaches a surface into which the screw is being drilled. The screw includes a shank with a tip end and a head end. A head at the head end may be driven by a driving tool such as a pneumatic or electric drill. To facilitate retention of the washer the head has a flange that forms a recess. The shank has an enlarged portion near the head adjacent to the recess and the enlarged portion has ridges. The enlarged portion, including the ridges, increases the driving resistance of the screw. This increase in resistance gives notice to an operator of the driving tool that an appropriate driving depth and torque have been achieved. Preferably, the washer has an inner diameter surface with fully radiused projections. The projections assist in mounting the washer to the screw and keeping the washer appropriately positioned on the screw during driving of the screw.