Office Chair Assembly and Positioning

The assembly and positioning of an office chair should follow the physical logic of 'bottom-up'. The specific steps and component installation positioning are as follows:

I. Basic Structure Installation

1. Five-Star Base and Casters: Place the five-star base with its front side facing up on a flat surface, ensuring the central hole is facing upwards. Align the metal rod of the caster with the foot hole and press vertically until it clicks into place (if it is a threaded type, tighten it clockwise until it can no longer rotate). After installation, gently shake the casters to check if they are secure and free from looseness.
2. Gas Lift Installation: Insert the thicker end of the gas lift vertically into the central hole of the five-star base, ensuring it is fully pressed down (some models may require removing the top plastic protective cap first). This step requires ensuring that the gas lift is perpendicular to the five-star base to avoid tilting, which could cause the chair to wobble later.

II. Seat Main Body Connection

1. Seat Base (Tray) Installation: Flip the seat cushion so that its bottom is facing up. Align the tray with the pre-installed screw holes on the bottom (pay attention to distinguishing the front and back directions; usually, the tray has a 'front' mark or curvature design). First, manually screw in all the screws loosely, then gradually tighten them using the 'diagonal tightening method' (i.e., tighten the two diagonal screws first, then the remaining two) to ensure a tight and seamless connection between the tray and the cushion.
2. Seat and Gas Lift Connection: Lift the seat with the installed tray, align the central hole of the tray with the top of the gas lift, and smoothly slide it down vertically. During this process, keep the seat level to avoid scratching the tray hole by the top of the gas lift.

III. Installation and Positioning of Other Components

1. Backrest and Armrests:
   • Insert the bottom sides of the backrest into the installation positions on both sides of the seat cushion, ensuring the backrest is perpendicular to the seat cushion.
   • First, use two C screws to fix the bottom of the backrest from the bottom of the armrest bracket (the screws need to penetrate the bracket and the backrest holes), then use two wrenches to lock and fix the backrest and the seat cushion bracket with D screws (i.e., one wrench fixes the screws on one side, and the other wrench tightens the screws on the opposite side to prevent offset due to unilateral force).
2. Headrest Installation: Place the headrest in the middle position at the top of the backrest, press the installation area to make it fit (some headrests need to be inserted into the card slot), and tighten it with two E screws through the fixing clip (the screws need to penetrate the clip and the backrest holes) to ensure the headrest is free from wobbling.
3. Armrest Surface Installation: Press the button below the armrest surface (some models have spring clips), insert the left and right armrests into the holes of the armrest brackets respectively, and a 'click' sound indicates that they are installed in place. After installation, gently push the armrest surface to check if it is secure and free from the risk of falling off.

Precautions: Before assembly, check if all screws and accessories are complete; avoid using excessive force during installation to prevent component damage; after all installations are complete, test whether the chair's functions such as lifting, rotation, and reclining are normal.