Buttons Under Office Chairs

The buttons or cylindrical knobs under office chairs are primarily used to adjust the backrest elasticity, tilt angle, and control the height adjustment function, with a few cases potentially having special uses. Here are the specific functions and operating methods:

1. Backrest Adjustment Function
Rotating the knob adjusts the elasticity of the backrest. When tightened clockwise, the backrest support increases, requiring more external force to lean back, suitable for scenarios where an upright sitting posture needs to be maintained. When loosened counterclockwise, the backrest elasticity decreases, allowing for a comfortable tilt angle with slight leaning back, suitable for relaxation or short breaks. Some high-end models have knobs that are linked to the lumbar support, adjusting the lumbar support position simultaneously when rotated, providing more precise lumbar support.

2. Height Adjustment Control
The knob may serve as a switch for the pneumatic rod, adjusting the chair height through rotation. When operating, maintain the correct sitting posture: sit on the chair with both feet flat on the ground and knees bent at a 90-degree angle. Some models may require slightly lifting the body to reduce the load on the pneumatic rod. After rotating the knob, the pneumatic rod achieves stepless height adjustment through internal nitrogen pressure, adjusting until both feet are fully in contact with the ground and the thighs are parallel to the ground. Note that the height adjustment function usually requires coordination with the pneumatic rod. If the chair does not have a pneumatic rod design, the knob may only be used for backrest adjustment.

3. Other Special Functions (Rare)
A few office chairs may have special buttons at the bottom, such as:

• Statistical Device: Records the chair usage time or sitting posture data to assist in health management;
• Storage Mechanism: Hidden drawers or slots for storing small items;
• Locking Function: Fixes the backrest tilt angle to prevent accidental movement.
  Such designs are more common in customized or high-end models, and the specific functions need to be confirmed in combination with the product manual.

Usage Suggestions
Before operating, observe whether there are any markings around the buttons (such as 'UP/DOWN' or backrest icons) or consult the manual to clarify the functions. Avoid pressing or disassembling forcefully without caution to prevent damage to the pneumatic rod or internal structure. If the knob is stuck, try rotating it slightly and adjusting the sitting posture, and do not use tools to force the operation. Regularly check the sealing of the pneumatic rod. If there is air leakage or difficulty in height adjustment, contact a professional for repair.