Half-Sitting Stool with Asymmetric Support for Neutral Lumbar Posture
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Solution Overview
Problem
Current sitting devices often fail to maintain neutral lumbar spine curvature, leading to discomfort and fatigue due to fixed positions, inadequate lumbar support, and uneven weight distribution, which can cause strain and pain, especially in users with spinal injuries.
Innovation Solution
A half-sitting stool design that allows one side of the pelvis to be vertically supported while the other side is supported by a standing leg, with a cutout in the seat for leg extension, enabling easy switching between supported and unsupported sides, and incorporating an anti-rotation mechanism to maintain stability and reduce core muscle exertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional chair places the thighs at 90 degrees in relation to the back, then the user can sit comfortably with legs supported, but the lumbar spine experiences flexion force that increases with decreasing back-thigh angle, causing fatigue and poor posture
Solution Approach 1:
The stool allows dynamic positioning where the user can alternate between having one leg supported on the footrest and the other leg unsupported, enabling periodic redistribution of stresses and pressure points while maintaining neutral lumbar curvature. This dynamic adjustment prevents the fixed-position fatigue associated with conventional chairs.
Solution Approach 2:
The sitting function is segmented into asymmetric support: one side of the body receives full support while the other side remains unsupported, allowing independent positioning of each leg. This segmentation enables the user to maintain neutral spine posture while periodically relieving pressure points through alternating leg positions.
2Reliability
If lumbar-support devices apply external force to the lumbar spine, then neutral curvature can be maintained, but the devices often do not apply enough pressure and are used ineffectually when the user does not sit far enough back
Solution Approach 1:
The stool design inherently promotes proper lumbar alignment through its geometry and anti-rotation mechanism, eliminating the need for users to actively engage with lumbar support devices. The structure itself provides the necessary support conditions, making effective lumbar care automatic rather than requiring user knowledge or effort.
Solution Approach 2:
The anti-rotation mechanism pre-prevents the trunk from rotating forward, which would cause lumbar flexion. By preventing the harmful motion before it occurs, the design eliminates the need for users to actively adjust their position or engage with separate lumbar support devices.
3Reliability
If saddle chairs, kneeling chairs, and perching stools increase back-thigh angle by positioning thighs at downward angle, then core-muscle effort is reduced, but these devices put significant pressure on the ischial tuberosities and soft tissue near the sit bones, causing discomfort
Solution Approach 1:
The stool provides localized support only to one side of the body at a time through the asymmetric footrest configuration, rather than distributing weight evenly across the sit bones as in conventional seats. This localized support approach reduces pressure on the ischial tuberosities while maintaining the ergonomic benefits of increased back-thigh angle.
Solution Approach 2:
The user can dynamically alternate between supporting the left or right leg on the footrest, periodically redistributing pressure away from the sit bones and soft tissue. This dynamic weight redistribution prevents the sustained pressure and discomfort associated with static asymmetric seating arrangements.
4Reliability
If sitting devices place the user in a fixed position, then posture can be maintained, but repositioning is necessary to redistribute stresses and pressure points and promote blood flow
Solution Approach 1:
The stool is designed for easy dynamic adjustment, allowing the user to periodically switch between supporting the left or right leg on the footrest. This simple dynamic repositioning action redistributes stresses and pressure points while maintaining neutral spine posture, combining posture reliability with ease of repositioning.
Data Source
AI summary
A seating apparatus for supporting a portion of a user, the seating apparatus comprising a reorientable seat portion including a seat platform and a cutout, wherein the seat selectively underlies a first ischial tuberosity of the user but not the second ischial tuberosity, the selection of which is determined by the orientation of the reorientable seat portion.