Headgear Torque Mitigation Using Dynamic Cable Tension
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Solution Overview
Problem
Existing headgear with offset weighted items cause unbalanced forces and stresses on the neck muscles due to torque and increased inertia, which are exacerbated by counterweights intended to mitigate torque, leading to additional weight and rotational resistance.
Innovation Solution
A stress mitigation system using a track, shuttle, and flexible elongate connector that applies a counter-torque to offset the torque exerted by weighted headgear components, maintaining a substantially vertical orientation of the connector during head movement, without the need for counterweights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a counterweight is added to the rear of the helmet to offset the torque applied by the night vision goggles, then the torque on the wearer's head is reduced, but the total weight that the wearer must bear increases
Solution Approach 1:
A flexible connector arrangement acts as an intermediary between the headgear and the bodywear member, transferring forces and torques in a way that mitigates neck muscle stress without requiring a rigid counterweight structure. The flexible connector can accommodate head movements while providing the necessary force balance.
Solution Approach 2:
The system changes the physical parameters of force transmission by using a flexible connector that can dynamically adjust its orientation and tension, rather than using a fixed rigid counterweight. This allows the system to maintain torque balance while adapting to different head positions and movements.
2Force
If a counterweight is added to the rear of the helmet, then the torque applied by the night vision goggles is neutralized, but the amount of inertia associated with the helmet increases
Solution Approach 1:
The flexible connector serves as a mediator that transmits force without requiring additional mass at the helmet. By distributing the counterbalancing force through the connector to the bodywear member, the system achieves torque neutralization without increasing the helmet's moment of inertia.
3Force
If a counterweight is added to the rear of the helmet, then the torque from the goggles is offset, but the stress on the wearer's neck muscles increases in certain situations such as when lying down
Solution Approach 1:
The flexible connector arrangement provides a dynamic solution that adapts to different body positions and head orientations. Unlike a fixed counterweight that creates constant torque, the flexible connector can change its geometry and force distribution based on the wearer's posture, reducing stress in various situations including when lying down.
Solution Approach 2:
The system dynamically changes the parameters of force transmission by allowing the flexible connector to adjust its tension and orientation according to the wearer's position, thereby optimizing the torque balance and minimizing neck muscle stress across different postures.
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
Reduces neck muscle stress by counteracting torque without adding weight or inertia, allowing for comfortable head movement and reducing rotational resistance.
Implementation Method 1
The flexible elongate connector is configured to connect between the shuttle and the other of the headgear and the bodywear member. When the wearer is upright, the flexible elongate connector is biased so as to apply a second torque on the headgear in a second torque direction that is generally opposite to the first torque direction.
Implementation Method 2
The headgear is configured to apply a load on the wearer that is offset from a center of gravity of a head of the wearer so as to apply a first torque in a first torque direction on the head of the wearer
Data Source
AI summary
In an aspect, a stress mitigation system is provided for mitigating stresses in a wearer of a headgear configured to apply a load on the wearer that is offset from a CG of a wearer's head. The system includes a first and second cable segments, and a tensioning device. Each cable segment has a first end and a second end, mounted to one of the headgear and the bodywear member respectively. The first ends are laterally inboard and vertically spaced from the second ends. During pivoting of the head in a first direction, the first cable segment changes orientation towards vertical and the second cable segment changes orientation towards horizontal, and during pivoting movement of the head in a second direction. The tensioning device increases tension in any cable segment that changes orientation towards vertical, and reduces tension in any cable segment that changes orientation towards horizontal.