Adjustable positioner for vehicle seat back headrest

1. A positioning assembly for a headrest on a vehicle seat back, comprising:

a pair of housings for mounting on an upper extremity of a vehicle seat back in a spaced relationship from each other, and each housing having a hole that extends generally vertically through the housing along an associated positioning axis;

a headrest support of a generally inverted U shape having a horizontally extending support portion for mounting a vehicle headrest and also having a pair of vertically extending shafts extending downwardly from the support portion and respectively received by the holes of the pair of housings;

one of the housings having an inner housing portion, a housing mount for mounting the inner housing portion on the seat back, the inner housing portion defining a lower portion of the generally vertical hole of the one housing, and the inner housing portion having an opening and an inclined ramp, the one housing also including an outer housing portion that receives the inner housing portion;

the one housing having a single helical spring that extends around the shaft within the hole of the one housing and the helical spring having first and second ends including portions that extend radially with respect to the positioning axis of the one housing, the radially extending portion of first end of the helical spring being received within the opening in the inner housing portion of the one housing to provide positioning of the helical spring with respect to the one housing, the helical spring adjacent the first end thereof being seated by the inclined ramp of the inner housing portion of the one housing, and the helical spring having a diameter of a size for clamping to the one shaft to prevent vertical movement of the headrest with respect to the seat back;

an actuator including a rotatable sleeve mounted within the outer housing portion of the one housing, the rotatable sleeve having an opening that receives the radially extending portion of the second end of the helical spring to provide a connection to the helical spring, the rotatable sleeve having an inclined ramp and a radial tab, the helical spring adjacent the second end thereof being seated by the inclined ramp of the rotatable sleeve, and the actuator also including a manual knob that is positioned above the seat back and having a slot that receives the radial tab of the rotatable sleeve to permit manually actuated rotation of the rotatable sleeve and the second end of the helical spring by rotation of the manual knob to unwind the helical spring and provide unclamping of the shaft of the one housing for infinite position vertical adjustment of the headrest with respect to the seat back; and

the opening of the inner housing portion and the opening of the rotatable sleeve each having an axial portion extending parallel to the positioning axis of the one housing to permit relative movement between the inner housing portion and the rotatable sleeve along the positioning axis of the one housing as the radially extending first and second ends of the helical spring respectively move through the axial portions of the openings during assembly.

2. A vehicle seat back headrest positioner as in claim 1 wherein the manual knob includes a pair of radially extending lobes located at diametrically opposite locations from each other about the positioning axis.