Chair Cover Assembly with Drawstring Tensioning for Movable Components

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Solution Overview

Problem

Existing chair designs lack an efficient mechanism for seamlessly integrating a cover member with movable chair components, leading to gaps that compromise user comfort and aesthetics, particularly in back assemblies where the cover alignment and tensioning are not effectively managed.

Innovation Solution

A chair design featuring a single-piece drawstring operably coupled with a cover member, which is wrapped around both static and movable chair components, allowing for adjustable alignment and secure fastening using raised portions and fasteners, ensuring proper cover alignment and tensioning as the components move between positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a cover member is wrapped around movable chair components, then aesthetics and user comfort are improved, but gaps appear between components when they move, compromising the fit

Engineering Contradiction:
Improvecover alignmentVSAvoidgap reduction
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The drawstring mechanism is made adjustable to dynamically adapt to the changing spatial relationship between chair components. As components move relative to each other, the drawstring length can be modified to maintain consistent tension and cover alignment, preventing gaps from forming between components during movement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The effective length of the drawstring is changed as a parameter to accommodate different positions of movable components. By adjusting this parameter, the system maintains optimal cover tension and alignment across the full range of motion, ensuring gaps are minimized regardless of component position.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a single-piece drawstring is used to secure the cover, then ease of operation is improved, but manufacturing precision is required to maintain proper tension

Engineering Contradiction:
Improvecover fasteningVSAvoiddrawstring length
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The single-piece drawstring is divided into multiple segments or sections that can be independently adjusted. This segmentation allows for finer control over the effective length and tension distribution, reducing the manufacturing precision requirements while maintaining ease of operation. Each segment can be adjusted to compensate for variations in component positioning.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The drawstring system incorporates dynamic adjustment mechanisms that allow users to modify the effective length in the field. This dynamic capability compensates for manufacturing tolerances and ensures proper tension without requiring extremely precise initial manufacturing, thereby maintaining ease of operation while reducing precision constraints.

Inventive Principle:
Principle #15Dynamics

3Shape

If the cover member is tensioned to eliminate gaps, then aesthetics are improved, but the movable components lose flexibility in movement

Engineering Contradiction:
Improvecover tensionVSAvoidcomponent movement
Core Design Contradiction:
ShapeVSAdaptability or versatility

Solution Approach 1:

The drawstring mechanism is designed to be dynamically adjustable, allowing the cover tension to adapt as components move. When components are in fixed positions, the drawstring can be tensioned to eliminate gaps and improve aesthetics. When components need to move, the drawstring tension can be reduced or released, maintaining flexibility while still providing aesthetic coverage when needed.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3915440A1Chair assembly
Publication Date: 2021.12.01 STEELCASE INC
  • EP3915440A1 patent drawingFigure 1~2
  • EP3915440A1 patent drawingFigure 3~4
  • EP3915440A1 patent drawingFigure 5

AI summary

A chair component includes a first chair member adapted to support a seated user, a second chair member movable between a first position, wherein the second chair member is substantially coplanar with the first chair member, and a second position, wherein the second chair member is substantially parallel with the first chair member, a cover member wrapped about at least a portion of the first chair member and at least a portion of the second chair member, and a single-piece drawstring operably coupled with the cover member to draw the cover member about the at least a portion of the first chair member and the at least a portion of the second chair member when the second chair member is in the first position.