Oblique Shoulder Strap for SCBA Harnesses

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Solution Overview

Problem

Existing shoulder straps for self-contained breathing apparatus (SCBA) harnesses are expensive and heavy due to their curved design, making them unsuitable for low-cost and low-weight harnesses, and they can become twisted when worn, compromising comfort.

Innovation Solution

A shoulder strap design featuring a first elongate strap portion extending along a longitudinal axis and a second oblique strap portion, both part of a single continuous piece of material, with folds and stitching to form loops and attachment points, and a length-adjustment mechanism using a buckle, ensuring comfort and preventing twisting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If curved shoulder straps are used to prevent twisting and ensure comfort, then comfort and anti-twisting performance are improved, but manufacturing cost and weight increase

Engineering Contradiction:
ImprovecomfortVSAvoidweight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The shoulder strap is divided into multiple straight segments (first strap portion, intermediate strap portion, second strap portion) connected by folds, rather than using a single curved strap. This segmentation allows the strap to achieve the necessary geometry through angular connections while using simpler, lighter straight sections.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The strap transitions from a two-dimensional curved design to a three-dimensional structure using folds and angular connections. The intermediate strap portion is folded at specific angles to create the oblique configuration, adding a dimensional aspect that achieves the desired shape without requiring heavy curved material.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If curved shoulder straps are used to prevent twisting and ensure comfort, then comfort and anti-twisting performance are improved, but manufacturing cost increases

Engineering Contradiction:
ImprovecomfortVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The strap is constructed from multiple straight segments joined by folds, which are simpler and less expensive to manufacture than complex curved straps. The angular geometry can be more easily cut and assembled from standard materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of creating a curved strap by bending material, the invention inverts the approach by using straight material segments and creating the curve effect through angular folds and oblique connections. This inversion simplifies manufacturing while achieving the same functional result.

Inventive Principle:
Principle #13The other way round (Inversion)

3Strength

If a single continuous piece of material is used for the strap portions, then structural integrity is improved, but flexibility and adjustability may be reduced

Engineering Contradiction:
Improvestructural integrityVSAvoidadjustability
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The continuous material is segmented into functional portions (first strap portion, intermediate strap portion, second strap portion) connected by folds. This segmentation provides structural integrity through continuity while allowing angular flexibility at the fold points for adjustability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The folds in the intermediate strap portion create dynamic, adjustable angles rather than fixed rigid connections. This allows the strap to adapt to different wearers and configurations while maintaining overall structural integrity through the continuous material.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2248440B1Shoulder Strap
Publication Date: 2018.07.18 DRAEGER SAFETY UK LTD
  • EP2248440B1 patent drawingFigure 1~2
  • EP2248440B1 patent drawingFigure 3~4b
  • EP2248440B1 patent drawingFigure 5~6

AI summary

The present invention relates to a shoulder strap 10 for a harness for breathing apparatus, comprising: a first elongate strap portion 20 generally extending along a first longitudinal axis; a second elongate strap portion 30 attached to the first strap portion and generally extending along a second longitudinal axis that is oblique to the first axis; and a first attachment portion 22 for attaching a first end of the shoulder strap to the harness in use and a second attachment portion 32 for attaching a second end of the shoulder strap to the harness in use.