Adjustable Office Chair Assembly

The assembly of an adjustable office chair generally follows a bottom-up sequence, with common assembly steps as follows:

Common General Assembly Method

1. Install the Chair Base and Gas Lift
   First, press each caster (universal wheel) into the holes on the chair base one by one, ensuring that each wheel is securely fastened without any looseness. After assembling the chair base, vertically insert the gas lift into the center hole of the chair base. Note that the metal end of the gas lift should face downward and the plastic end should face upward to provide stable support for connecting other components later.

2. Secure the Seat Plate to the Chair Seat
   Use the provided screws to fix the seat plate to the bottom of the chair seat. Align the screw holes and tighten them evenly to prevent the seat plate from tilting. The seat plate usually comes with an adjustment handle, which should be installed facing outward for easy operation of the height adjustment function later.

3. Connect the Chair Back to the Chair Seat
   Align the pins on the chair back with the slots on the back of the chair seat, insert them diagonally, and then gently press down until you hear a 'click' sound, indicating that the buckle is in place. Some chair backs require additional installation of a cover or decorative strip, which should be pasted flat according to the instructions to cover the pin structure.

4. Assemble the Upper Body with the Gas Lift
   Lift the part of the chair seat that is already connected to the chair back, and vertically insert the center hole of the seat plate onto the top of the gas lift, ensuring sufficient insertion depth and no wobbling. At this point, you can briefly sit on it to test the stability of the connection, but avoid vigorous shaking.

5. Install the Armrests and Headrest
   Finally, fix the armrests to both sides of the chair seat with screws, ensuring left-right symmetry. The headrest is directly inserted into the reserved hole at the top of the chair back, and some models require rotation to lock it in place. After installation, check that all screws are tightened and that movable parts (such as armrest adjustment and headrest angle) are flexible.

Special Model Assembly Example (Livorno M40)

1. Five-Star Base and Gas Lift
   The installation method of the universal wheels is the same as that of the general model, but the gas lift needs to be inserted into the center hole of the five-star base first, then into the center hole of the base plate, and finally flip the base plate upright to form a vertical structure of 'gas lift-base plate-five-star base'.

2. Connection between the Chair Seat and the Chair Back
   The chair back adopts a diagonal insertion design. Align the pins on the chair back with the slots on the back of the chair seat, insert them diagonally, and then press down until the buckle is fixed, without the need for additional screws. The pin cover should be pasted flat to avoid curling and affecting aesthetics.

Precautions: Before assembly, count all the accessories and check the specifications and quantity of the screws; avoid tilting the gas lift during installation to prevent damage to the internal seals; tighten all screws in stages to avoid misalignment of components caused by tightening them all at once.