Harness Strap Length Adjustment Device with Movable Deflection Axes
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Solution Overview
Problem
Existing safety harnesses with elastic materials face degradation over time due to physical/chemical aging and are more complex and costly to produce, while mechanical adjustment devices have limitations such as irreversibility of displacement axes.
Innovation Solution
A device that adjusts the apparent length of a flexible link by forming a loop whose extent varies with pulling force, using a return means to increase loop extent in the absence of force, reducing apparent length, and elongating it with force, employing mechanisms like springs or shape memory materials to mimic elasticity without intrinsic extendibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If elastic materials are used in the harness to allow freedom of movement, then comfort characteristics are improved, but mechanical strength degrades over time due to physical/chemical aging processes
Solution Approach 1:
The device segments the harness system into a non-elastic link and a mechanical adjustment device with movable deflection axes. The link itself remains inextensible for strength, while the device provides the elastic-like behavior through movable axes that adjust under load and return to original position, eliminating aging degradation of elastic materials.
Solution Approach 2:
The mechanical adjustment device acts as an intermediary between the non-elastic link and the user's body. It transforms the inextensible link into an effectively elastic component through the action of movable deflection axes that displace under pulling force and return automatically, providing comfort without compromising the link's inherent strength.
2Ease of operation
If elastic materials are used in the harness to provide comfort, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The device employs movable deflection axes that dynamically adjust their position in response to pulling forces on the link. At least one deflection axis can displace along a translation path, creating an dynamic, elastic-like effect in an otherwise static, non-elastic link without requiring complex elastic material construction.
Solution Approach 2:
The mechanical adjustment device is self-regulating through its movable deflection axes that automatically displace under load and return to their original positions when the load is removed. This self-service mechanism eliminates the need for complex control systems or active components, simplifying production while providing the desired comfort characteristic.
3Reliability
If mechanical adjustment devices are used to adjust link length, then reliability is improved, but device complexity increases due to irreversibility or absence of displacement of deflection axes
Solution Approach 1:
The device introduces mobility to at least one deflection axis, allowing it to displace along a translation path when pulling force is applied to the link. This dynamic capability enables the device to adjust to different link lengths while maintaining reliable fall retention, avoiding the irreversibility problem of fixed-axis mechanisms.
Solution Approach 2:
The movable deflection axis provides automatic feedback-based adjustment: when pulling force is applied, the axis displaces to accommodate the elongation; when force is removed, the axis returns to its original position. This passive feedback mechanism ensures reliable fall retention while simplifying the device compared to active control systems.
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 device provides comfort and safety by allowing freedom of movement while ensuring effective fall retention, maintaining mechanical strength, and reducing production complexity and costs.
Implementation Method 1
the return means is a spring
Implementation Method 2
the return means tending to increase the extent of the loop up to a predefined maximum in the absence of pulling force on said link
Implementation Method 3
the return means has shape memory (block of rubber for example)
Data Source
AI summary
A device for adjusting the length of a flexible link according to the pulling force exerted on the link, the continuous link passing through the device between two substantially opposite input/output ends of the device. The device includes elements for producing at least one link loop whose extent can vary according to the pulling force, at least one return element tending to increase the extent of the loop up to a predefined maximum in the absence of pulling force on the link and which corresponds to a reduction of the apparent length of the link on which the device is placed, the pulling force of the link resulting in a reduction of the extent of the loop up to a predefined minimum and which corresponds to an elongation of the apparent length of the link on which the device is placed. Devices with S loop or omega loop are described together with a comfort unit for a strap harness.