US 6,669,292 · Granted 2003-12-30
The Four-Bar Linkage That Revolutionized Office Chair Comfort
This patent describes a smart office chair that uses a system of connected bars and pivot points to tilt backward in a way that lifts your seat slightly while keeping your feet flat on the floor. The clever geometry means your head stays level and your thighs don't get squeezed—exactly what your body actually needs during an 8-hour workday.
The plain-English version
What it protects
The claim covers a specific four-bar linkage mechanism in an ergonomic chair where a seat member pivots on the front support of the lower frame, a backrest connects to the rear support, and a link member bridges the seat and backrest. What's protected is this exact arrangement of pivot points and rigid supports that allows the backrest to tilt rearward while simultaneously raising the rear of the seat, maintaining hip alignment and preventing thigh pressure—the geometry itself is the invention.
Why it matters
This patent addresses a real ergonomic problem: traditional chairs that recline either cut off blood flow to your legs or force your feet off the floor. By engineering a linked mechanism that coordinates backrest tilt with seat elevation, Hon Technology created a solution that lets office workers maintain comfort and proper posture simultaneously. The patent locks down this specific mechanical solution, preventing competitors from copying the exact linkage design without licensing.
Real-world use
Every time you lean back in a modern office chair and notice your feet stay planted while your backrest reclines and your seat tilts up slightly, you're experiencing the coordinated pivot system this patent protects.
Original USPTO abstract
An ergonomic chair includes a four-bar linkage arrangement wherein a lower frame member is provided with a rigid front support and a rigid rear support with a seat member pivotably connected to the front support. A back rest has an upper support pivotably connected at an upper end of the rear support of the lower frame member. A link member pivotably connects at a first end to a rear support of the seat member and at second end to a lower support of the back rest. This novel arrangement permits tilting movement of the backrest rearwardly relative to the lower frame member causing elevation of a rear portion of the seat member, permitting the feet to remain on the floor and alleviating pressure on the user's thighs, while rotation occurs closely coincident with the pivot axis of the user's hips and while maintaining a generally uniform gaze line.
Patent details
- Publication number
- US 6,669,292
- Filing date
- 2002-02-15
- Grant date
- 2003-12-30
- Assignee
- Hon Technology Inc.
- Inventor(s)
- —
- CPC class
- A47C31/126
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