Alcoa Inc.

Arconic Corporation

Howmet Aerospace Inc.

James L Wollard

Donald C Busby

Richard Franklin

Robert J Corbett

A fastener including a bolt having an elongated shank having a first end, a second end opposite the first end, and a threaded portion having an external bolt thread, the bolt thread including a bolt pitch. The fastener includes a nut having a first end, a second end opposite the first end of the nut, and an internal nut thread extending between the first and second ends of the nut and adapted to engage threadedly the bolt thread of the bolt. The nut thread includes a nut pitch and a hardness that changes gradationally between the first and second ends of the nut. The bolt pitch of the bolt thread of the bolt is mismatched with the nut pitch of the nut thread of the nut.

Advanced nut and bolt

A vibration resistant fastening system including a high fatigue strength bolt made from a first material and a nut made from a second material that is softer than the first material of the bolt. The bolt includes bolt threads and the nut includes pre-tapped nut threads that match with the bolt threads. The fastening system utilizes a combination of unique geometry of the nut and bolt threads and a hardness differential between the nut and bolt to provide vibration resistance. When tightened, crests of the bolt threads embed into the soft bearing flanks of the nut threads. Simultaneously with the bolt crest embedment, the softer nut thread crests flow radially inward into the root radius of the bolt threads. This complete contact between the nut and the bolt restricts the nut from moving in a transverse direction relative to a longitudinal axis of the bolt.

Growing community of inventors

Waco, TX, United States of America

James L Wollard