Arm rest for office chair has base plate mounted on top of upright using double joint made up of upper and lower ball-and-socket joints linked by connecting rod

摘要

The arm rest for an office chair has a base plate (4) which is mounted on the top of an upright (3) using a double joint. This is made up of upper and lower ball-and-socket joints (6, 7) linked by a connecting rod (10).