Illinois Tool Works Inc.

William A Spring

Francis C Peterson

Michael Starozhitsky

William G Rodseth

Mark D Bauer

S Riaz Hasan

S Riaz U L Hasan

A carbon steel screw has one or more portions which have been selectively hardened by selective heat treatment and quenching. In one embodiment, an upper portion of the screw head is selectively hardened to prevent or reduce damage when torque is applied using a driving tool. In another embodiment, the screw tip is selectively hardened for more effective penetration into a substrate. Preferably, the selectively heated portions are selectively quenched to reduce or avoid distortion.

Method for selectively hardening a carbon steel screw

Screws having selected heat treatment and hardening

The invention relates to a fastener assembly for use in attaching articles to printed circuit boards, and include a fastener, which has a generally tubular body, flanged at one end, is adapted to receive a screw. The fastener has a polygonal cross-section over a portion of its length. The flange which is located at one end of the tubular body, has an integral spring washer and includes indentations which allow solder to flow from one side of the printed circuit board to the other. The fastener with its integral spring washer provides improved clamping characteristics and avoids problems associated with large coefficients of thermal expansion of printed circuit board material in a direction perpendicular to the board.

Printed circuit board fastener

The invention includes a method and a fastener for use in attaching articles to printed circuit boards. The fastener, which has a generally tubular body, flanged at one end, is adapted to receive a screw. The fastener has a polygonal cross-section over a portion of its length. The flange which is located at one end of the tubular body, has an integral spring washer and includes indentations which allow solder to flow from one side of the printed circuit board to the other. The fastener with its integral spring washer provides improved clamping characteristics and avoids problems associated with large coefficients of thermal expansion of printed circuit board material in a direction perpendicular to the board.

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Geneva, IL, United States of America

William A Spring