Office Chair Iron Base

The 'iron base' of an office chair typically refers to the chassis, which is the core component located beneath the seat cushion, connecting the seat cushion, backrest, and gas lift. Its main functions include fixing and connecting various components, enabling reclining, and facilitating adjustments. It is mostly made of metal plates (some with plastic casings), and uses springs or torsion springs inside to enable reclining, while its structural design supports various adjustment needs.

The functions and structural characteristics of the chassis can be summarized as follows:

1. Basic Connection and Support As the 'skeleton' of an office chair, the chassis secures the seat cushion, backrest, and gas lift with bolts or clips, ensuring overall structural stability. Its metal material (such as steel plates) provides high-strength support, capable of bearing human weight and dynamic pressure, preventing deformation or loosening after long-term use.

2. Reclining Function Implementation The chassis integrates a spring or torsion spring system inside, enabling the backrest to recline through elastic deformation. Different chassis have significantly different reclining mechanisms:

• Ordinary Chassis (Fixed Type): No reclining function, only used in low-cost chairs (such as bow chairs, four-legged chairs), with a rigid structure to fix the backrest angle.
• Single Reclining Chassis: The backrest can recline but cannot lock the angle, suitable for basic swivel chairs, meeting the need for short breaks.
• Single Reclining Chassis with Lock: The reclining angle can be locked (such as 90° for office mode, 120° for rest mode), and some models support adjusting the reclining tension to accommodate users of different weights.
• Synchronous Tilt Chassis: When reclining, the seat cushion and backrest move in proportion (such as a 2:1 ratio), avoiding the 'butt lift' phenomenon, enhancing lumbar support comfort, and commonly found in mid-to-high-end ergonomic chairs.
• Cable-Controlled Chassis: Controls reclining lock, angle adjustment, and other functions through a handle, offering convenient operation without bending over.
• Gravity-Sensing Chassis: Built with an intelligent sensing device that automatically adjusts the reclining resistance according to the user's weight, achieving 'stepless adaptation', often seen in high-end models.

3. Adjustment Function Expansion The design of the chassis directly affects the adjustment dimensions of an office chair. Mainstream chassis support reclining angle locking and reclining tension adjustment, while some high-end models also integrate seat depth adjustment, armrest linkage adjustment, and other functions to meet personalized needs. For example, the synchronous tilt chassis achieves precise linkage between the seat cushion and backrest through gears or link mechanisms, while the cable-controlled chassis simplifies the operation process through mechanical or electronic systems.

4. Grade and Suitable Scenarios The type of chassis is closely related to the price of an office chair:

• Low Price Range (Below 500 yuan): Mostly use ordinary chassis or single reclining chassis, with single functions, suitable for short-term use scenarios (such as conference chairs, student chairs).
• Medium Price Range (500-1500 yuan): Generally equipped with single reclining chassis with lock or synchronous tilt chassis, supporting basic adjustment functions, suitable for daily office use.
• High Price Range (Above 1500 yuan): Use cable-controlled chassis or gravity-sensing chassis, integrating multi-dimensional adjustments and intelligent functions, suitable for long-term office use or users with high comfort requirements.