A chair structure comprises a seat frame having a first coupling element, a support base, and a pivot link assembly mounted on the support base. The pivot link assembly includes a pivot axle, and a second coupling element pivotally mounted around the pivot axle. The second coupling element includes a latch operable to lock the first coupling element with the second coupling element when the seat frame is assembled with the support base, and unlock the first coupling element from the second coupling element for allowing separation of the seat frame from the support base.