Functions Under the Office Chair

The rotatable cylinder or disc (i.e., the base) under an office chair primarily serves functions of adjustment, rotation, and height adjustment, with specific roles as follows:

1. Adjusting the Recline Force
   The base is typically equipped with knobs or control levers that allow users to adjust the elasticity of the chair back's recline by turning them clockwise or counterclockwise. For example, turning counterclockwise may reduce the recline resistance, making it easier for the chair back to recline; turning clockwise may increase the resistance, suitable for scenarios requiring a fixed sitting posture. This function is achieved through mechanical structures inside the base (such as springs or dampers), allowing users to adjust flexibly according to their weight or usage habits, enhancing comfort.

2. Controlling the Recline Angle and Locking
   The base incorporates mechanical modules for the recline function, enabling users to lock the tilt angle of the chair back by operating control levers or knobs. For example, setting the control lever to a specific gear can fix the chair back at angles such as 120° or 135°, preventing accidental recline during use; some high-end bases also support stepless adjustment to meet diverse needs. Additionally, the adjustment knob can control the force of the chair back's rebound, ensuring a smooth return to the upright position when getting up.

3. Enabling Horizontal Rotation
   The base allows the chair seat (including the cushion and backrest) to rotate horizontally around the axis of the gas lift through bearings or rotating mechanisms. This design enables users to easily turn around to retrieve items, communicate with colleagues behind or to the side, or fine-tune the angle facing the computer without moving the chair, significantly improving office efficiency. The rotation function typically supports 360° free rotation, and some bases are equipped with damping designs to prevent imbalance due to rapid rotation.

4. Connecting to the Gas Lift for Height Adjustment
   The lower end of the base connects to the top of the piston rod of the gas lift (gas spring) through a central hole or sleeve. The height adjustment function of the chair relies on the nitrogen pressure difference inside the gas lift: when the user triggers the height adjustment lever, the piston rod extends or retracts, transmitting power to the chair seat through the base to achieve height adjustment. The connection between the base and the gas lift must ensure airtightness to prevent air leakage from causing height adjustment failure, and it must withstand the weight of the human body, so the material is usually high-strength metal or engineering plastic.

Summary: By integrating mechanical structures with the gas lift, the office chair base achieves four core functions: recline adjustment, angle locking, horizontal rotation, and height control, making it a key component for the chair's comfort and practicality.