Split-Seat Sit-Stand Chair for Lumbar Lordosis Support
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Solution Overview
Problem
Prolonged static sitting postures exacerbate or initiate low back pain due to the reduction in the thigh-torso angle, which increases strain on the spine's posterior passive elements, and existing chair designs do not effectively replicate the standing posture that naturally maintains lumbar lordosis.
Innovation Solution
A sitting device with two independently position-adjustable half seats that can be controlled to support the user in a standing posture while maintaining at least half of the body weight, allowing the user to switch between a standing and sitting position, featuring mechanisms like pneumatic cylinders or rotors with manual or programmable control for height and position adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the user maintains a standing posture to keep lumbar lordosis, then back pain is reduced, but the user cannot rest the full body weight
Solution Approach 1:
The seat is divided into two independent half seats (left and right), each capable of being independently positioned in supporting or collapsed state. This segmentation allows the user to receive partial weight support from one half seat while maintaining standing posture, or full support from both half seats for complete sitting position, thus resolving the contradiction between back pain reduction and body weight support.
2Object-affected harmful factors
If existing chair designs increase the thigh-torso angle, then back pain is reduced, but the posture remains unnatural and does not reach ideal 180 degrees
Solution Approach 1:
The half seats are designed to be dynamically adjustable between supporting and collapsed positions through actuators (pneumatic cylinders or linear motors). This dynamic capability allows the chair to adapt to different user needs: maintaining natural standing posture with lumbar lordosis when half seats are collapsed, or providing supported sitting when both half seats are in supporting position, thus achieving both back pain reduction and posture naturalness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively reduces back pain by maintaining the natural lumbar lordosis of the standing posture and provides the option to use it as an ordinary chair by positioning the half seats in a supporting configuration.
Implementation Method 1
The piston of a pneumatic cylinder or any equivalent mechanism, which is for height adjustment of the whole sitting device, is housed and travels inside the vertical guide tube of the seat support frame
Implementation Method 2
The position of each half seat is controlled by the length of the linear actuator, which in turn is controlled by the user via manual switches or by a programmable control box
Implementation Method 3
The position of each half seat is controlled by the angular position of the rotor which in turn swings the attached supporting arm. When the supporting arm swings forward, the attached half seat rises to a supporting position; when the supporting arm swings backward, the attached half seat retracts
Data Source
AI summary
A sitting device that gives the user an option to sit with a lower portion of the body supported by a half seat, while maintaining a standing posture with the unsupported leg. The sitting device includes two, left and right, half seats and a foot stool. The device also includes a seat support frame and two half-seat-position-adjusting actuators. The frame includes a horizontal crossbar and a vertical guide tube, wherein the back end of each of the two half seats is pivotally secured on the horizontal bar. The vertical guide tube houses a length-changing mechanism to vary the height of the sitting device and a height fixing mechanism which prevents yielding of the height of the sitting device when the user sits. Also comprising are the two half-seat-position-adjusting actuators attached at one end of each to the vertical tube and at the other end to the respective half seat.