Reclining chair headrest with height adjustment mechanism

A chair comprising:

• at least one leg;
• a seat rotatably mounted on a top portion of the at least one leg;
• a backrest extending upwardly from a rear end of the seat;
• and
• a headrest comprising:
• a clamping member comprising an upper yoke including two opposite, hollow, cylindrical yoke arms;
• two intermediate spaced hook members extending forward downward from both sides of the yoke respectively;
• and a lower well;
• a support comprising a cup-shaped hinge head pivotably disposed between the yoke arms;
• and two opposite fastening portions;
• a head frame comprising two rear bars and two joints each frictionally, slidably fastened on the bar, each joint being frictionally, pivotably secured to the fastening portion;
• a hooking member fastened in the well and comprising two spaced hook elements curved upward forward wherein the hook elements cooperate with the hook members to releasably mount the headrest on an upper portion of the backrest;
• a first hinge element pivotably disposed in one yoke arm and comprises a lever;
• and
• a second hinge element moveably disposed in the other yoke arm and the hinge head, wherein the lever can be rotated counterclockwise to securely fasten the hinge head.