Telescoping Chair Armrest Latch for Simple Height Adjustment

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Solution Overview

Problem

Existing chair armrest adjustment mechanisms are complex, difficult to operate, and costly to manufacture, leading to reliability and warranty issues while providing limited adjustable positions.

Innovation Solution

A vertically adjustable armrest assembly featuring a tubular support, telescopingly positioned armrest assembly, and a height adjustment mechanism with an actuator rod, locking member, and resilient member, utilizing an angled ramp, inclined surfaces, and detents for easy and secure height adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If complicated latching and securing mechanisms are added to make armrests more adjustable and secure, then adjustability and security are improved, but device complexity and ease of operation deteriorate

Engineering Contradiction:
ImproveadjustabilityVSAvoidmechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The armrest mechanism is divided into separate functional components: a telescoping adjustment mechanism for height variation and a simple latch mechanism for positioning锁定。This segmentation allows each component to perform its function independently, reducing overall complexity while maintaining adjustability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The latch mechanism is designed to automatically engage and disengage without requiring complex operations. The user simply needs to apply minimal force to release the latch, and the mechanism self-locks into position, eliminating the need for complicated securing procedures.

Inventive Principle:
Principle #25Self-service

2Adaptability or versatility

If complicated latching and securing mechanisms are added to make armrests more adjustable and secure, then adjustability and security are improved, but ease of operation deteriorates

Engineering Contradiction:
ImproveadjustabilityVSAvoidoperation ease
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The latch mechanism is designed to automatically engage and disengage without requiring complex operations. The user simply needs to apply minimal force to release the latch, and the mechanism self-locks into position, eliminating the need for complicated securing procedures.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The complex securing operations have been extracted from the user's task. The latch mechanism handles the securing function automatically, requiring only a simple user action to initiate the process, thereby greatly improving ease of operation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If multi-part mechanisms are used to provide adjustment functionality, then adaptability is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
ImproveadjustabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The armrest mechanism is divided into separate functional components: a telescoping adjustment mechanism for height variation and a simple latch mechanism for positioning锁定。This segmentation allows each component to perform its function independently, reducing overall complexity while maintaining adjustability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple functions are merged into fewer components. The telescoping mechanism provides both height adjustment and positioning capabilities, while the simple latch handles securing. This consolidation reduces the number of parts and simplifies manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If multi-part mechanisms are used to provide adjustment functionality, then adaptability is improved, but reliability deteriorates

Engineering Contradiction:
ImproveadjustabilityVSAvoidmechanism reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The armrest mechanism is divided into separate functional components: a telescoping adjustment mechanism for height variation and a simple latch mechanism for positioning锁定。This segmentation allows each component to perform its function independently, reducing overall complexity while maintaining adjustability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The latch mechanism is designed as a simple, robust component that can be easily replaced if needed. Its simplicity means fewer failure points and easier maintenance, improving overall reliability despite being a single-use component in the adjustment process.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 simplifies the armrest adjustment process, reduces manufacturing complexity and costs, and provides a wide range of adjustable positions for user comfort while maintaining reliability.

Implementation Method 1

a resilient member. The actuator rod includes an angled ramp, an inclined surface, and a pair of angled surfaces, and the locking member includes teeth, an inclined surface, and a pair of lateral followers

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2160120B1Height adjustable armrest
Publication Date: 2012.10.31 STEELCASE INC
  • EP2160120B1 patent drawingFigure 1~2
  • EP2160120B1 patent drawingFigure 3
  • EP2160120B1 patent drawingFigure 4

AI summary

A vertically adjustable armrest includes a tubular support constructed for attachment to a chair, an armrest assembly telescopingly positioned in the tubular support, and a height adjustment mechanism slidably received in the armrest assembly. The armrest assembly includes a sleeve and a post. The height adjustment mechanism includes an actuator rod, an operative member, a locking member, and a resilient member. The actuator rod operatively engages the locking member with the inclined wedge mateably engaged with the inclined surface and the angled surfaces slideably engaged with the lateral followers. To vertically adjust the armrest, the operative member is lifted upward, causing the resilient member to compress and the teeth of the locking member to disengage from the detents. To reengage the teeth with the positional detents, the operative member is released.