Dissection of Office Chair Cylinder

The dissection of an office chair cylinder mainly involves two aspects: core structure and disassembly methods.

Core Structure

1. Piston Assembly: Composed of a metal piston with an annular lip seal. Its function is to divide the cylinder barrel into two independent air chambers, upper and lower. The seal ensures airtightness of the chambers, preventing air leakage.
2. Air Chamber Assembly: Utilizes a seamless metal cylinder barrel with end caps at both ends to form a closed air cavity. It is filled with low-pressure air or inert gas, with a pressure range of 0.2 - 0.5MPa, complying with the GB/T 28202 - 2011 'Structural Safety Requirements for Office Chairs' standard.
3. Control Mechanism: A foot-pedal-triggered two-position three-way directional control valve. The valve stem is connected to the air passage inside the cylinder. Foot-pedal operation enables switching between the on and off states of the air chambers, thereby controlling the lifting and lowering of the office chair.

Disassembly Methods

1. Pressing Method: Suitable for most chairs with normal structures. First, invert the chair and clear the space beneath the base. Locate the metal retaining clip embedded in the groove on the inner side of the connection between the gas spring and the base. Use a slender tool (such as a small flat-head screwdriver) to gently press inward on the gap or both sides of the retaining clip. After hearing a 'click' sound, steadily pull the gas spring upward with your hand to separate it from the base.
2. Striking Method: Used when the retaining clip is difficult to press or the gas spring and the base/seat are seized due to long-term use and rust. Invert or side-lay the chair. Use a rubber mallet or an ordinary hammer wrapped in a thick towel to evenly and moderately strike around the metal ring connecting the gas spring to the base (or seat) in a circular motion. After striking a few circles, try to pull upward or shake slightly left and right. For stubborn cases, apply lubricating oil to the connection gap and let it sit for 1 - 2 hours before striking again.
3. Rotating Method: Mainly used when the threaded connection between the gas spring and the seat (upper end) is seized. First, apply lubricating oil to the threaded connection. Use a pipe wrench or locking pliers to grip the metal part of the gas rod (as close to the connection as possible). Rotate it counterclockwise with force (usually a reverse-thread connection) while holding the seat steady until the gas spring is unscrewed.

Precautions: The gas cylinder of a lifting chair is a pressurized and sealed component. Non-professionals are strictly prohibited from disassembling it privately. When disassembling and releasing pressure, operate slowly. Ensure the chair is stably fixed during disassembly, keep your hands steady, and use appropriate force when striking. If you are not familiar with the disassembly and assembly process, it is advisable to seek help from professionals.