Adjustable Strap Mechanism That Preserves Set Tension
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Solution Overview
Problem
Traditional adjustable strap systems for head-worn devices, such as head-mounted displays, often require users to lose the set tension when adjusting the straps for donning or doffing, leading to discomfort or complexity in maintaining the desired fit.
Innovation Solution
A strap adjustment device featuring a pinion gear, racks, a rotatable cam element with angled surfaces, and a spiral spring mechanism that allows for length adjustment without rotating the adjustment knob, maintaining the set tension during donning and doffing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a strap system is designed to accommodate different body types and sizes, then adaptability is improved, but device complexity increases due to multiple adjustment mechanisms
Solution Approach 1:
The patent implements dynamic adjustability through movable adjustment mechanisms that allow the strap length and configuration to be changed based on user needs. The adjustment mechanism includes a movable connector that can slide along the strap to modify effective length, enabling the same strap to adapt to different body sizes and application requirements without requiring multiple fixed-length straps
Solution Approach 2:
The strap system is designed with multi-functional capabilities to serve various applications (e.g., different bag types, wearable devices) using a single unified structure. The adjustment mechanism and connector design allow the same strap to function across multiple use cases, reducing the need for specialized straps for each application while maintaining adaptability
2Adaptability or versatility
If adjustment mechanisms are added to modify strap length and configuration, then adaptability is improved, but manufacturing complexity increases
Solution Approach 1:
The strap is divided into modular segments including adjustable portions, fixed portions, and interchangeable connectors. This segmentation allows each component to be manufactured independently using standardized processes, simplifying production while enabling complex adjustment capabilities through assembly of pre-manufactured modules
Solution Approach 2:
The adjustment mechanism utilizes parameter changes in the form of movable connectors that can be positioned at different locations along the strap to modify effective length. This approach allows a single strap design to provide multiple length configurations without requiring multiple different strap variants, reducing manufacturing complexity while maintaining adaptability
3Reliability
If a ratchet mechanism is used to maintain consistent tension, then reliability is improved, but device complexity increases
Solution Approach 1:
The ratchet mechanism is designed as a self-tensing system that automatically maintains consistent tension on the strap without requiring external intervention or complex control systems. Once adjusted, the ratchet mechanism self-regulates to prevent slack and maintain proper tension, providing reliable performance through passive mechanical action rather than active control
Solution Approach 2:
The ratchet mechanism acts as an intermediary component between the strap and the anchor point, mediating the tension forces to ensure consistent loading. This intermediary element simplifies the overall system by providing a dedicated, specialized component for tension maintenance rather than requiring complex integrated control mechanisms
Data Source
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AI summary
The disclosed strap adjustment devices (100) may include a pinion gear, with a first rack (206) secured to a first strap (104) and a second rack (208) secured to a second strap (106) each engaged with the pinion gear (214). A rotatable cam element (306) may include an angled radially outer surface that is at an angle to a circumference of the rotatable cam element. A bearing element (316) may be positioned adjacent to the angled radially outer surface such that the bearing element jams between the angled radially outer surface and a braking surface when the rotatable cam element is rotated in a jamming direction. A spiral spring (308) may be coupled to the pinion gear and the rotatable cam element to allow for an increase in length of the first and second straps upon application of a tension force to the first and second straps. Various other methods, systems, and devices are also disclosed.