Patent ID: 7445397

Claim:
A height adjustable accessory structure operatively connecting a headrest to a seat, the accessory structure comprising: an engaging sleeve, an engaging rod and a sleeve; wherein the engaging sleeve includes a main sleeve body and an assistant sleeve body separably engaged with each other, a top side of the main sleeve body having an annular flange, an inner surface of each of the main sleeve body and the assistant sleeve body being formed with an inner annular groove, the annular groove accommodating a C-shaped ring that engages with a plurality of engaging portions of the engaging rod so as to provide a positioning effect after height adjustment, each of the main and assistant sleeve bodies being received within the sleeve and each having an elastic hook located at both sides of a bottom of the engaging sleeve, the engaging rod being inserted into the engaging sleeve with the hooks and the annular flange sandwiching the sleeve therebetween to provide a fastening effect, wherein the bottom of the engaging rod includes an outer annular groove that receives a C-shaped engaging member, the C-shaped engaging member preventing removal of the rod from the engaging sleeve.