Planning for a Weight-Separated Floating Chair

In short, this is about whether we can distribute and support body weight using a hammock combined with the cushion of a high-end chair underneath it.

Prompt:

A system chair where a hammock-style cushion that supports about 20kg of body weight is lowered from the ceiling, and a full-scale chair that supports the remaining weight is placed directly underneath it.
It would be difficult to move and large-scale, but couldn't it provide an interesting seating experience?

ChatGPT's response:

It has the potential to provide a quite interesting seating experience. If built well, it would become a 'semi-gravity chair' where only part of your body weight is floating, rather than just a regular chair.

What is particularly promising is a method that doesn't just lift the buttocks with a hanging cushion, but broadly wraps from the back to the pelvis, lifting about 15-25% of the body weight upward. For a 70kg person, you could start from about 10-18kg and make it adjustable up to about 20kg. The full-scale chair underneath would stably support the remaining weight and legs.

The sensations you can expect are as follows:

• Reduced pressure concentrated on the lower back and ischium

• A feeling of being softly wrapped by the back, with a sensation of floating slightly

• Posture is not as unstable as a hammock, but the body is not as fixed as in a normal chair

• Slight body movements are transmitted to the hanging fabric, causing it to sway slowly

• Can reduce the 'feeling of the buttocks being crushed' when sitting for long periods

However, simply hanging fabric from the ceiling and layering it over a chair probably won't be very comfortable. If the positions of the hanging fabric and the chair shift slightly, the buttocks will be pulled upward while the back is pulled diagonally backward, causing clothing and skin to rub constantly. Also, if the suspension is a fixed length, the supported load will change from '20kg to almost zero' or 'suddenly over 30kg' the moment you change your posture.

Therefore, the key is a mechanism that winds up with constant force.

If you incorporate a mechanism similar to a tool spring balancer on the ceiling side, you can continue to apply a generally constant upward force even when you move your body. By using a 4-point suspension that separates the back side and the pelvic side, rather than just two on the left and right, you can also adjust the load distribution.

The form that seems most likely to have a high degree of perfection is the following configuration:

• Lower part: High-end reclining chair. Supports the head, lower back, thighs, and legs normally

• Upper part: A highly breathable, thin net cushion that wraps from below the shoulder blades to the pelvis

• Suspension load: Adjustable in the range of 5-20kg

• Left and right loads also finely adjustable individually

• A "floating mode" that allows for micro-swaying, and a "focus mode" that stops the swaying

• Automatically loosen the suspension cushion when standing up

• Even if the suspension hardware were to detach, the chair a few centimeters below would catch the entire body weight

Conversely, what I want to avoid is a system that supports 20kg solely through the armpits, chest, and abdomen. It creates a strong sense of pressure, leading to arm numbness and difficulty breathing. A system that lifts only the buttocks with a narrow suspension cloth also concentrates force on the crotch and the base of the thighs. The key is not to "suspend from a single point," but to distribute the load across the back and pelvis.

Furthermore, even with a device that quietly lifts 20kg of human body weight, the dynamic load caused by the moment of sitting down or swaying will far exceed 20kg. It is an absolute requirement that the ceiling hardware and beams be designed to support at least the full weight of a person plus impact, and that they are not attached to plasterboard.

If commercialized, it would be better positioned as a "weight-separating floating chair" rather than "a chair placed under a hammock." If it is packaged as high-end furniture for reading, watching movies, or napping, rather than looking like medical equipment, it would become a quite unique product that people would want to try sitting in at least once. The greatest appeal would not be the softness, but the sensation—not found in ordinary chairs—of "the body's weight being divided between two upper and lower support surfaces."weight-separating floating chairas a position.

My thoughts:

It has turned into an ultra-high-end chair. If we go the ultra-high-end route, we might even be able to make a "semi-gravity bed with a canopy."