Locking fastener

DETAILED DESCRIPTION This invention is directed to providing an improved locking fastener which is effective to preclude loosening of the associated nut even under high frequency vibratory load conditions.
The invention is further directed to reducing or eliminating the requirements for different coefficients of friction between the various involved surfaces.
The invention basically comprises adding a spring means to the wedge ramp construction and arranging the spring means in such a way that it is compressed or otherwise loaded as the mating wedge surfaces are moved relative to each other as the nut is tightened.
Thus a portion of the energy expended to tighten the nut is used to load the spring means.
In broad combination, the invention locking fastener comprises a first portion; a second portion movable relative to the first portion; means operative in response to relative movement between the portions in one direction to decrease the overall axial height of the fastener and operative in response to relative movement between the portions in the opposite direction to increase the overall height of the fastener; and spring means yieldably resisting relative movement of the portions in the one direction and biasing the portions for movement in the opposite direction.
With this arrangement, as the portions are moved relative to each other in the tightening operation to decrease the overall axial height of the fastener, the spring means is loaded so that it tends to bias the portions for movement in a direction to expand the overall height of the fastener and thereby augment the locking action of the fastener.
According to a basic feature of the invention, the expansion means comprises coacting, parallel, first and second ramp surfaces on the first and second portions inclined at a greater angle than the thread angle of the associated threaded member.
With this arrangement, as the associated nut is threaded onto the associated threaded member, the ramp surfaces move relative to one another in a direction to decrease the overall axial height of the fastener so that loosening movement of the fastener results in attempted expansion of the overall height of the fastener with a resultant resistance to the loosening action