Locking key for threaded insert

A locking key for use with an insert installed in a threaded opening in a carrier material, said key having an upper locking portion and a lower tang portion, the insert having a cylindrical body portion, an exterior thread on said body complementary to and for engagement with the thread of the opening, and a slot in the body portion longitudinally interrupting the insert exterior thread, said key being constructed for positioning in the slot for installation therein, wherein the improvement comprises:

• said locking key tang portion having spring retention means for retaining said key in the insert slot;
• said spring retention means including an aperture that defines a flexure area centrally located on said tang portion and a pair of protrusions centrally located in opposing relation along said flexure area, said protrusions each including a leading surface constructed for guiding said key into and along the insert slot.

A combination comprising:

• an insert having an externally-threaded cylindrical body portion adapted to be threaded into a threaded opening in a carrier material, said body portion having a longitudinally-extending slot in its outer, threaded surface, said slot having undercut sidewalls;
• and
• an elongated locking key having an upper locking portion and a lower tang portion, wherein the lower tang portion has a width greater than the width of the insert slot, and includes means for providing resilient inward flexing of said tang portion of greater width, to allow the lower tang portion to side axially within the slot, without deforming the slot, and to allow the locking key to be frictionally held in a selected axial location.