Patent attributes
An adjustable screen lift arm includes a support frame assembly with a frame base, a balance adjustment mechanism including a gear set consisting a drive gear and a sector-like driven gear, a gear rack meshed with the drive gear and a spring connected between the frame base and the driven gear, and a holder block assembly has a holder block body that combined with the gear rack and a first sliding rail, the other side combined with a second sliding rail. When the holder block body is moved vertically, the gear rack rotates the drive gear, causing the driven gear to stretch or compress the spring so that the arm of force is relatively changed to offset the spring force of the spring, enabling the holder block assembly to be freely adjusted to the desired elevation and then automatically positioned.
