Contributed by the Mechanisms and Robotics Committee for publication in the JOURNAL OF MECHANICAL DESIGN. Manuscript received March 2001. Associate Editor: J. S. Rastegar.

A review 1 of research on vibration and shock–induced loosening of threaded fasteners reveals a common thread throughout: the primary mechanism of self-loosening is relative slip within the threads and fastener nut or head interfaces. Such slip is caused by forces and moments which manifest themselves in joints through bending, pressure fluctuations, shocks, impacts, thermal expansion, and axial force fluctuations.

This work presents a locking fastener design that is an innovative variation of existing cam-type locking devices 2,3,4. This design replaces the inclined mating cams with counter-threads thereby eliminating the problem of bottoming out. In addition, this design utilizes a helical torsion spring to provide a controllable and adjustable amount of spring torque or moment...

1.
Hess, D. P., 1998, “Vibration and Shock–Induced Loosening,” Chapter 40, Handbook of Bolts and Bolted Joints, Marcel Dekker Inc., New York, pp. 757–824.
2.
White, G., 1996, Private Communication, Disc-Lock International, Culver City, California.
3.
Hosko, M. J., 1996, Private Communication, Nord-Lock, Lake Michigan Wire Technologies Inc., Muskegon, Michigan.
4.
Terry, S. L., 1999, “Maximizing and Preserving Bolt Tension in Threaded Fasteners,” Proceedings of the Second International Conference on Nonlinear Problems in Aviation and Aerospace, Daytona Beach, Florida, pp. 731–744.
5.
Orthwein, W. C., 1990, Machine Component Design, West Publishing Company, New York.
6.
Junker
,
G. H.
,
1969
, “
New Criteria for Self-Loosening of Fasteners under Vibration
,”
SAE Trans.
,
78
, pp.
314
335
.
You do not currently have access to this content.