Sub-assembly effecting the elastic return of the position-retention device belonging to a ski binding

Ski binding comprising a position-retention element and a device for effecting elastic return of said position-retention element, said device comprising a compression spring (6) comprising turns, an adjustment screw (7) passing completely through said spring, a nut (10) forming a support stop for one of the ends of said spring and screwed on a threaded end (9) of said screw, and a device (5) connected to said position-retention element and movable parallel to a longitudinal axis of said spring in conjunction with movements of said position-retention element, said device (5) connected to said position-retention element housing said spring (6) and opposing an elastic return force of said spring, wherein said screw has a central portion comprising a shoulder (16) against which said nut (10) abuts in an end compression position of said spring, and, in said end compression position, the turns of said spring remain spaced apart, said nut (10) being made of plastic material and being partially enclosed by a circular metal ring (19) which prevents expansion of said nut when said nut abuts against said shoulder (16) of said screw in said end compression position of said spring.