Orthopedic chairs - Self adjusting and automatic chairs

One of the most recent concepts in orthopedic and ergonomic chair design is that of a chair that can automatically adjust itself to the shape of the person sitting on it.

Naturally, with adjustable settings plus padding and cushioning, there is a degree to which many task chairs can accommodate the curves of a body to some degree, however, there are major limitations because the chairs are always based around a fixed frame.

Despite this, efforts have and are being made to produce chairs that not only offer optimum support, but that also replicate the human spine in their frame design. At present these chairs are not commercially available, however it will not be long before they start to emerge into the orthopedic and ergonomic chair market.

What automatic self adjusting chairs try to do

The big difference between a task chair with lots of adjustable components and features and an automatic chair is a simple one.

With an adjustable task chair each component, e.g. the backrest, seat etc, is adjusted both separately and manually by the seated person. One feature is set, then the next, and at each stage an assessment is made of how the chair feels. There is no direct interdependency of one feature to another and, moreover, the features for the seat and the backrest are treated as totally independent components.

None of this ties in with the body's geometry which sees all parts of the human anatomy as being interconnected, interacting and totally dependent upon one another.

Self adjusting chairs seek to remedy this in two ways.

Firstly, they have a design that uses a frame composed of many separate panel-like segments. Theses segments are able to move independently, however they are interconnected and consequently the movement of one section has a corresponding effect on the section that it connects with. This duplicates the way that the vertebrae of the spine interrelate and it does (in theory) allow the chair to move and bend in harmony with the back.

Secondly, this design means that the chair can be reactive to the human body and as a result it can shape and reshape itself to the back and spine with any and every movement.

The result is that the chair automatically sets itself to the user without the need to manually adjust levers or change lot of settings.

The idea appears perfect, but the technology and resulting cost mean that these automatic chairs are very expensive, very heavy and sometimes take some getting used to.

How they work in practice

The constant objective of an automatic self adjusting back chair is that it is always trying to conform to the shape of the spine, however, how this works varies between different chairs.

Some chairs have an initial “floating” feature where all of the panels are free and flexible. When this is the case it is necessary to sit comfortably in the chair and then press a locking feature that fixes the chair in this optimised position. Other designs see the chair setting itself and making small adjustments as movements take place.

The key to the effectiveness of the chair's support is the independent and mobile support segments. These can be based around joints that use spring systems, so that they shape whilst offering resistance, or by using motorised segments to do the same thing (this is the more expensive option).

Some of these chairs us this technological approach to create the backrest, but the better chairs will have an interconnected seat and backrest where a segmental construction is utilised throughout. When this is the case the chair's orthopedic advantages will be at an optimum.

The advantage of this kind of chair is that, aside from initially shaping itself to the profile of the spine, it helps improve posture by gradually helping the back relax and improving positive muscle memory.