Office Chair Test Disc

The disc used in office chair testing is mainly used to simulate human body load or apply specific test forces, commonly seen in scenarios such as backrest recline fatigue testing, back-tipping testing, and caster durability testing. Here are the specific application descriptions:

1. Backrest Recline Fatigue Testing
When simulating long-term human use scenarios, the testing instrument (such as the HD-F738 model) prevents the chair from moving by fixing the chair wheels and then places an iron disc load on the seat surface. The function of this disc is to evenly distribute pressure and simulate the static weight distribution when a person is sitting, and its weight is usually set according to testing standards (e.g., 75 kg or 100 kg). At the same time, the instrument applies dynamic loads to the backrest, adjusting the angle and frequency (e.g., 10-20 reclinations per minute) to verify the durability of the backrest connection structure, springs, or gas rods. If the disc design is unreasonable (e.g., off-center of gravity), it may lead to deviations in test results, so its size and weight need to strictly match standard requirements.

2. Back-Tipping Testing (with backrest tilt structure)
According to the ISO 21015 standard, back-tipping testing evaluates the chair's anti-tipping ability under a loaded state. During testing, the disc is placed on the seat surface and firmly pressed against the backrest. By gradually increasing the load (e.g., from 50 kg to 150 kg), it is observed whether the chair tips backward due to the shift of the center of gravity. In this scenario, the rigid design of the disc is crucial. If the material is too soft or the surface is smooth, it may lead to ineffective load transfer and fail to accurately simulate the pushing force of the human body on the backrest. Some tests also add weight blocks to the edges of the disc to enhance the stress concentration effect in the edge area.

3. Caster Durability Testing
The caster testing platform drives a metal disc to rotate via a cylinder, enabling the casters to complete reciprocating linear motion on a specific track (e.g., 100,000 cycles). At this time, the function of the disc is to simulate uneven ground or obstacle impacts. The centrifugal force generated by its rotation exacerbates the wear of the caster bearings, while the alternating radial forces applied can test the connection strength between the wheel hub and the bracket. During testing, the surface roughness, diameter (usually 300-500 mm), and rotation speed of the disc must comply with standards to ensure that the results reflect the caster lifespan in real-world use scenarios.

Core Principles of Disc Design
Regardless of the testing application, the disc must meet characteristics such as rigidity, adjustable weight, and stable contact surface. For example, iron discs are widely used in static load testing due to their high density and minimal deformation. Metal rotating discs, on the other hand, require surface treatment (e.g., sandblasting) to enhance friction and prevent slippage during testing. Additionally, the installation method of the disc (e.g., whether it is fixed with bolts) also affects test repeatability and needs to be optimized according to specific standards.