Low envelope chair with high back pitch
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Solution Overview
Problem
Fixed chairs in auditoriums and stadiums have a limited seating capacity due to strict fire codes requiring larger clear passages, which restricts comfort and reduces the number of rows that can be accommodated within a given space, as smaller envelope sizes compromise back pitch and overall comfort.
Innovation Solution
Designing a low envelope chair with varying back pitch sections, allowing for a combination of high and low pitch angles to maintain comfort while reducing the chair's overall envelope size, enabling more rows to be accommodated within the same space by optimizing the chair's design to fit within the minimum fire code clear passage requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the chair envelope is reduced to increase seating capacity, then more rows can be accommodated in the same space, but the back pitch decreases resulting in reduced comfort
Solution Approach 1:
The backrest is divided into multiple sections with different pitch angles. The lower section has a higher pitch angle for comfort, while the upper section has a lower pitch angle to reduce the overall envelope depth, allowing more rows to fit in the same space while maintaining comfort in the seating area.
Solution Approach 2:
Different sections of the backrest are given different geometric properties (pitch angles) according to their functional requirements. The lower portion near the seat requires higher pitch for comfort, while the upper portion can have lower pitch to minimize envelope depth, creating local optimization throughout the structure.
2Reliability
If the clear passage width is increased to meet fire codes, then safety is improved, but the number of rows that can be accommodated decreases
Solution Approach 1:
By segmenting the backrest into sections with varying pitches, the overall envelope depth is reduced, which directly increases the clear passage width available for egress while maintaining the same row spacing, thereby improving fire safety without sacrificing seating capacity.
Solution Approach 2:
The backrest design utilizes vertical dimension optimization by varying pitch angles at different heights, which allows the envelope to be compact in the depth direction while maintaining comfort, thereby freeing up horizontal space for wider clear passages.
3Area of stationary object
If the envelope size is minimized to fit more rows, then space utilization improves, but the back pitch becomes too small to provide adequate support
Solution Approach 1:
The backrest is segmented into multiple sections where the lower section provides high pitch angle for adequate back support and comfort, while the upper section uses lower pitch angle to minimize the overall envelope depth, thus achieving both comfort and space efficiency.
Solution Approach 2:
The backrest structure implements local quality by providing different pitch characteristics in different regions - the lower region near the seat has higher pitch for support, while the upper region has lower pitch to reduce envelope depth, optimizing both comfort and space utilization locally.
Data Source
AI summary
A low envelope chair with a back that includes portions with relative high back pitches at the lower ends and other higher portions with relatively low back pitches to give the overall feeling of a high back pitch chair while retaining the low envelope. By low envelope, generally less than approximately 17 inches, preferably approximately 16 inches or less or even more preferably approximately 15 inches or less are contemplated with respect to chairs that have a tilt up seat. A high back pitch would generally be more than 15 degrees, preferably more than 20 degrees, preferably more than 25 degrees and even more preferably more than 30 degrees.