Locking threaded fastener
A locking fastener includes a fastener body, a locking band within the fastener body, and a retainer secured to the fastener body to retain the locking band within the fastener body. The locking band includes first and second tangs that fit within recesses in the fastener body to limit angular movement of the tangs. The tangs and the recesses are dimensioned to control the torque required to remove the fastener from a threaded member. The retainer defines a central circular hole corresponding to the diameter of a threaded member on which the fastener is mounted.
1. A locking threaded fastener comprising:
a fastener body having a threaded portion and an unthreaded portion defining a bore, the fastener body further having a shoulder and defining first and second recesses open through the shoulder and communicating with the bore, the first and second recesses are isolated from the environment surrounding the fastener body;
a single locking element including a coil portion and first and second tangs extending from the coil portion, the locking element located within the bore, the first and second tangs extending into the first and second recesses respectively to engage the fastener body upon rotation of the fastener body, the locking element circumferentially surrounded without interruption by the fastener body; and
a retainer at least partially covering the locking element and retaining the locking element within the bore and the first and second tangs within the first and second recesses respectively.
2. The locking fastener of claim 1 wherein the first and second tangs extend generally tangentially from the coil portion.
3. The locking fastener of claim 1 wherein the retainer snap fits within the fastener body.
4. The locking fastener of claim 1 wherein the retainer is elastic.
5. The locking fastener of claim 1 wherein the retainer is uninterrupted to completely cover the locking element.
6. The locking fastener of claim 1 wherein the first tang is angularly fixed with respect to the fastener body, and the second tang has a range of angular movement with respect to the fastener body.
7. The locking fastener of claim 6 wherein the second recess includes a second recess wall, the second tang adapted to contact the second recess wall during loosening of the locking fastener.
8. The locking fastener of claim 6 wherein the first recess includes a first recess wall, the first tang adapted to contact the first recess wall during tightening and loosening of the locking fastener.
9. The locking threaded fastener of claim 1 wherein the retainer includes a lip retaining the locking element.
10. The locking fastener of claim 1 wherein the retainer defines an aperture having an internal diameter corresponding to the diameter of the threaded portion of the bore.
11. The locking fastener of claim 10 wherein the retainer is elastic and adapted to seal against a threaded member on which the locking fastener is mounted.
12. The locking threaded fastener of claim 9 wherein the retainer wall defines a second shoulder that engages the retainer.