Sinking of Central Axis of Office Chair

The sinking of the central axis of an office chair is usually caused by a malfunction of the gas lift rod or issues with the adjustment locking mechanism, and can be resolved by inspecting, repairing, or replacing components.

Common Causes

1. Sealing Issues with the Gas Lift Rod
   Over time, the sealing ring of the gas lift rod may age or wear out, leading to leakage of high-pressure nitrogen gas and a decrease in support force. Additionally, if the nitrogen gas filled inside the gas lift rod is not pure enough or has sealing defects, it can also cause unstable pressure, resulting in the sinking of the central axis.
2. Adjustment Valve Failure
   If the valve mechanism that controls the lifting and lowering gets stuck or damaged, it will prevent the gas lift rod from locking properly. Even if adjusted to the target height, it will slowly descend due to the failure of the locking mechanism.
3. Loose Connecting Components
   If the connecting screws between the base, gas lift rod, and seat are not tightened properly, they may become loose over time due to vibrations or stress, causing the central axis to lose stable support.

Solutions

1. Temporary Emergency Fix
   Raise the chair to its highest point and temporarily lock it using the mechanical limit. Alternatively, use external supports such as wooden blocks or hard plastic tubes to pad the lifting rod at an appropriate position to prevent further sinking.
2. Inspection and Tightening
   Flip the chair over and focus on inspecting the screws at the connections between the base and gas lift rod, and between the gas lift rod and seat. Use tools to tighten all visible screws to ensure a secure connection.
3. Simple Repair Attempt
   If the sinking is caused by slow air leakage due to poor sealing at the top of the cylinder, try adding 1-2 drops of engine oil around the vent button or sealing ring to temporarily increase the sealing (only applicable to some models).
4. Replacement of the Gas Lift Rod
   If the gas lift rod has cracks, rust, or deformation on its surface, or if the above methods are ineffective, stop using it immediately and replace the gas lift rod. If the chair is severely aged overall, it is recommended to replace it with a new one to ensure safety.

Safety Tips

• Do not disassemble the body of the gas lift rod when handling it, as the high-pressure gas or components inside may pose a danger.
• Low-quality pneumatic lifting chairs carry a risk of explosion. When purchasing, choose products that have passed safety certifications and avoid overloading them.