US 4,529,247 · Granted 1985-07-16
The Herman Miller Chair That Flexes With Your Body
Imagine a chair made from a single piece of material where the backrest and seat cushion can move independently, bending slightly to match the shape and movement of your body. It's designed so that when you shift or lean back, the chair flexes with you instead of fighting against you, kind of like how a good mattress molds to your sleeping position.
The plain-English version
What it protects
The claim covers a one-piece molded chair shell where the seat and backrest are connected by flexible straps that allow them to move independently. What's protected here is the specific geometry of the H-shaped opening in the shell that creates these flexible zones, plus the way the backrest pivots around the occupant's hip joint. Also protected is the tilt mechanism that lets the entire chair rock forward and backward while keeping the user's feet flat on the floor.
Why it matters
This patent represents a major shift in office furniture design—moving away from rigid chairs to ones that actively respond to human movement. By allowing the backrest and seat to flex separately, the chair reduces strain on the spine and lower back, a real problem for people sitting for hours. For Herman Miller, one of the world's leading furniture makers, this kind of innovation in ergonomics helped define the modern office chair category and set them apart from competitors still making stationary seats.
Real-world use
Every time someone sits in an Aeron chair or other modern ergonomic office chair, they're benefiting from this basic idea: a flexible shell that moves with your body as you shift positions throughout the day.
Original USPTO abstract
A one-piece shell chair (10) includes an unitary integrally formed shell body (12) having a flexurally supported seat pan (14) and a flexurally supported backrest (16) defined in part by an H-shaped opening (20) in the shell body. The backrest (16) and the seat pan (14) resiliently flex as independent units in response to an occupant's body shape, size, posture and positioning. Integral, flexible straps join the backrest (16) to the seat pan (14) to permit resilient flexing of the backrest (16) with respect to the seat pan (14) about an axis through the occupant's hip joint to minimize shear between the backrest and the occupant's back during flexing movement of the backrest 16 with respect to the seat pan 14. The seat (12) is mounted to a tilt mechanism (28) which pivots the seat (12) about an axis forward and below the front edge (14a) of the seat pan (14) enabling the user's feet to remain stationary on the floor. Accordingly the seat (12) and tilt mechanism (28) provide a comfortable, convenient and accommodating chair (10).
Patent details
- Publication number
- US 4,529,247
- Filing date
- 1982-04-15
- Grant date
- 1985-07-16
- Assignee
- Herman Miller, Inc.
- Inventor(s)
- STUMPF; WILLIAM E., CHADWICK; DONALD T.
- CPC class
- A47C3/026
Want to file your own patent?
If you're designing a new piece of furniture, start by searching IsItPatented's free database to see what shell structures and flex mechanisms are already locked down.
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