Office Chair Hydraulic Knob

The office chair hydraulic knob is a core device for controlling seat height adjustment and some other adjustment functions. It achieves stepless adjustment by manipulating the pneumatic or hydraulic rod, and some high-end models also support adjustments such as backrest elasticity and tilt angle.

I. Core Functions and Operating Methods

1. Height Adjustment Function

   • Pneumatic/Hydraulic Rod Control: The knob or adjustment lever controls the opening and closing of internal valves, using high-pressure nitrogen (pneumatic rod) or hydraulic oil (hydraulic rod) to achieve height adjustment. For example, lifting or pulling the adjustment lever upwards opens the valve, allowing the seat to rise; releasing it closes the valve, locking the height. Some models use a screw-type adjustment, directly changing the height through mechanical threads by rotating the knob clockwise or counterclockwise.
   • Screw Adjustment: If the chair has no obvious buttons or manual control levers, the height can be adjusted by turning the screw below the hydraulic rod (requiring the seat cover to be opened): turning the screw counterclockwise lowers the height, and turning it clockwise raises it.

2. Other Adjustment Functions

   • Backrest Adjustment: The knob on high-end office chairs may control backrest elasticity, tilt angle, or rebound force. For example, rotating the knob below the backrest can change the force required to tilt backward and the rebound strength.
   • Independent Component Adjustment: Adjustments to components such as the headrest, armrests, and lumbar support are usually controlled by independent knobs or buttons, separate from the height adjustment function, and require operation according to the specific design.

II. Safety Precautions

1. Pneumatic Rod Quality: Poor-quality pneumatic rods pose an explosion risk. When purchasing, prioritize products that have passed safety certifications such as SGS, BIFMA, and TUV, and check if there is a protective chassis at the top of the pneumatic rod.
2. Usage Guidelines: Avoid frequent and rapid height adjustments, and do not exceed the weight limit (usually the upper limit is 100-130 kg); if you hear a hissing sound or feel that the height adjustment is stuck, stop using it immediately and contact a professional repair technician.

III. Operating Suggestions

1. Correct Height Adjustment: When adjusting, ensure that your feet are flat on the ground, your thighs are parallel to the ground, your knees are at a 90-degree angle, and your line of sight is level with the top of the computer screen to maintain a healthy sitting posture.
2. Troubleshooting: If the knob cannot be turned or the chair cannot be adjusted in height, first check if the operating method is correct (e.g., the seat must be empty when raising and weighted when lowering); then check if the locking mechanism or screw connections are loose, or contact after-sales service for repair.