Lock nut

Claim 1

In a lock nut in combination with an externally threaded element of predetermined thread profile, pitch, pitch diameter and hardness, the improvement comprising a body portion of a material relatively softer than the material of said threaded element so as to preclude cutting of said threaded element by said lock nut, said body portion having a central axis and a circular cylindrical opening extending therethrough coaxially with said central axis, the opening in said body portion having three equally circumferentially spaced, radially outwardly extending relief grooves on the periphery thereof, the relief grooves in said body portion extending axially the entire length of said opening and being of like arcuate configuration and radial spacing from the central axis of said body portion, said relief grooves defining three equally circumferentially spaced axially extending land sections therebetween respectively, said relief grooves and said land sections being of substantially equal circumferential dimension, said land sections being provided with a thread form having a pitch, sense and profile similar to said threaded element, the relief grooves in said body portion extending radially outwardly to at least the root depth of the thread profile on said land sections, the thread form on the lands of said nut, respectively, having a pitch diameter relatively less than the pitch diameter of the threAds on said threaded element, whereby the lands on the body portion of said nut are elastically deflected radially outwardly upon engagement with said element to provide substantial surface-to-surface contact between the threads of said nut and the threads of said element as well as balanced pressure on each of said lands.