Patent attributes
A chair includes a positioning unit that is provided in a receiving portion of an armrest and that includes shorter and taller stop portions. A positioning member is retained movably on a rear side of a backrest, and has one end extending into the receiving portion to abut against a selected one of the stop portions. An operating unit is connected to and is operable to move the positioning member for selectively disengaging and engaging the stop portions. A safety mechanism is provided on the backrest and the operating unit, and is operable in either a limiting state, where the positioning member is unable to move past the taller stop portion, or a non-limiting state, where the positioning member is able to move past the taller stop portion.