Abstract: A chair armrest joint adjustable for 360° in any direction about a shaft includes a fix member, a movable member and a rotatable member, fixed between an armrest and the seat of a chair. The movable member is fixed on a connector fixed on the armrest, and the fix member is fixed on a seat bracket. When the rotatable member is rotated in one direction, the movable member may be rotated to let the armrest slope in any direction, disengaged from the fix member. Then the rotatable member is rotated reversely to force the movable member to engage with the fix member to lock the movable member and the armrest in the adjusted position. The fix member and the movable member both have teeth on their contacting surface to engage with each other or disengage from each other.

Abstract: An office chair armrest device includes two armrests and two L-shaped armrest supporters. Each armrest has a second connect member with a lateral pivot hole formed in a rear end, and each armrest supporter has a first connect member with a lateral pivot hole formed in an upper end of a vertical portion. A pivot extends in the lateral pivot holes of both the first and the second connect members to pivotally connect the armrest with the armrest supporter fixed with a side of a seat and a vertical side of a backrest. The armrest can be easily swung to a horizontal condition for the arm of a user to rest thereon or to a vertical condition if the armrest is not used.