Outer Leaf-Spring Banquet Chair for Stack-Safe Upholstery
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Solution Overview
Problem
Banquet chairs with fabric-covered cushions often suffer damage from repeated or incorrect stacking, as the fabric surface is vulnerable to contact with chair legs during stacking.
Innovation Solution
A banquet chair design featuring a pair of arcuate leaf springs that flexibly couple the backrest to the legs, with the outermost edge of the springs exposed through the backrest's lateral perimeter, providing a bearing surface for stacked chairs to prevent damage to the fabric. This design includes a slimmer portion at the bottom of the backrest to accommodate leg contact, reducing fabric wear and tear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If banquet chairs are designed with fabric-covered cushions for comfort, then seating comfort is improved, but the fabric surface becomes vulnerable to damage during stacking
Solution Approach 1:
The patent introduces an intermediary protective structure consisting of exposed leaf spring edges that act as a mediator between the chair legs and the fabric upholstery. When chairs are stacked, the legs of the upper chair contact the exposed leaf spring edges rather than directly impacting the fabric, thereby protecting the fabric from damage while maintaining the comfortable upholstered seating surface
2Productivity
If chairs are designed to be stackable for space efficiency, then storage efficiency is improved, but repeated stacking damages the fabric cover
Solution Approach 1:
The patent applies preliminary action by pre-positioning the exposed leaf spring edges in a location that anticipates and prevents fabric damage before stacking occurs. The leaf springs are deliberately designed to extend beyond the backrest perimeter, creating a predetermined protective barrier that intercepts chair legs during the stacking operation, thereby enabling repeated stacking without fabric damage
Solution Approach 2:
The exposed leaf spring edges serve as an intermediary protective element between the stacking operation and the fabric cover. This intermediary structure absorbs the impact and friction that would otherwise directly affect the fabric, allowing chairs to be stacked repeatedly while preserving the fabric cover integrity
3Ease of manufacture
If the backrest is designed with a uniform width for structural simplicity, then manufacturing simplicity is maintained, but it cannot accommodate leg contact during stacking without damaging fabric
Solution Approach 1:
The patent applies local quality by creating a non-uniform backrest design where the lateral perimeter is intentionally reduced at specific locations to expose the leaf spring edges. This localized modification allows the backrest to maintain uniform width in most areas for structural simplicity, while creating specific zones with exposed springs that provide protective bearing surfaces for chair legs during stacking, thereby preventing fabric damage without requiring complete redesign of the entire backrest structure
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 solution enhances stackability while protecting the fabric surface by allowing chair legs to bear against the leaf springs instead of the upholstery, preserving the chair's finish and appearance during stacking.
Implementation Method 1
A pair of arcuate leaf springs flexibly couples the backrest to the plurality of legs
Data Source
AI summary
A banquet chair comprises a seat and a backrest carried by a plurality of legs. A pair of arcuate leaf springs flexibly couples the backrest to the plurality of legs. The pair of arcuate leaf springs is spaced-apart, and each is located closer to a different outside edge of the seat and the backrest than to each other or a middle of the seat and the backrest. Each of the pair of arcuate leaf springs has an outermost edge exposed through a lateral perimeter of the backrest.