本机构为同步倾仰底盘，拥有4档锁定，具有回力安全保护功能，调节拉线A可使底盘自由升降；拉线C可调节座和背的角度，座的角度为$1\sim {11}^{\circ }$，背的调节角度为$90\sim {115}^{\circ }$；手柄F可快速调节弹簧松紧，拥有4档力度可调；手柄E可调节座的起始角度，可调节2个位置，分别为前倾$3^{\circ }$ 和后仰$1^{\circ }$。

Synchronized mechanism with backrest return prevention safety function and 4 locking positions: cable paddle A is for seat height, cable paddle C is for seat and back movement. The seat angle is in the range of $1\sim {11}^{\circ }$ and back angle is $90\sim {115}^{\circ }$ . Paddle F is for quick spring tension shift in four steps. Paddle E is for seat initial angle adjustment. The seat initial angle is $3^{\circ }$ forward and $1^{\circ }$ backwards.