Cable Tensioning Dial With Silent Non-Back-Drivable Locking
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Solution Overview
Problem
Current dial-based cable tensioning systems are noisy and fail to maintain consistent pressure over time, leading to irritation and discomfort in applications like headwear and footwear.
Innovation Solution
A tensioning system featuring a cam wheel with a roller-and-wedge mechanism that locks and unlocks silently, preventing back-drivability and maintaining tension through a dial wheel mechanism with angular restraints, ensuring consistent pressure and quiet operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a dial-based cable tensioning system is used, then tension adjustment capability is provided, but noise is generated during manipulation
Solution Approach 1:
The patent replaces the traditional friction-based dial mechanism with a cam-and-roller mechanical system. The cam profile converts rotational motion into linear roller displacement, eliminating the need for continuous friction contact. This substitution reduces noise by removing the sliding friction between dial components while maintaining tension adjustment capability through the cam's geometric profile.
Solution Approach 2:
The patent extracts and eliminates the noise-generating friction components from the dial mechanism. By removing the traditional friction-based tensioning elements and replacing them with a cam-roller system, the harmful noise factor is taken out while preserving the essential tension adjustment function through the cam's mechanical advantage.
2Ease of operation
If a conventional dial mechanism is used, then tension adjustment is possible, but consistent pressure cannot be maintained over time
Solution Approach 1:
The cam mechanism is designed with a self-locking profile that automatically maintains constant tension on the cable. As the roller follows the cam contour, the geometry itself provides the locking action without requiring additional springs or adjustment mechanisms. The system serves itself by using the cam's inherent geometric properties to maintain pressure consistency over time.
Solution Approach 2:
The cam profile is pre-designed with specific geometric characteristics that anticipate and compensate for tension variations. The contour is engineered beforehand to provide the exact force needed to maintain consistent cable tension, eliminating the need for real-time adjustments or feedback mechanisms.
3Reliability
If a locking mechanism is added to prevent back-drivability, then tension stability improves, but device complexity increases
Solution Approach 1:
The patent merges the locking function directly into the cam mechanism itself. The cam profile and roller work as an integrated unit where the locking action is inherent to the cam's geometric design. This consolidation eliminates the need for separate locking components, maintaining tension stability while avoiding additional complexity.
Solution Approach 2:
The roller acts as an intermediary element between the cam and the cable tensioning system. It transfers the cam's geometric motion into controlled cable tension while providing the locking action. This intermediary approach achieves reliable tension stability through a single, simple component rather than multiple complex locking mechanisms.
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 system provides silent, non-back-drivable tensioning that maintains consistent pressure across contact surfaces, reducing noise and discomfort while preventing over-spooling and ensuring secure fitment of headwear and footwear.
Implementation Method 1
The roller can be configured to roll along the ramped surface to lock the cam wheel and the dial housing in response to the cable moving in a first direction
Implementation Method 2
The cam wheel can include a roller opening and a ramped surface defining the roller opening. The ramped surface is inclined relative to a line tangential to a point on the dial housing in contact with the roller
Implementation Method 3
The roller can be configured to roll along the ramped surface to lock the cam wheel and the dial housing in response to the cable moving in a first direction
Data Source
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AI summary
There is provided a head-mountable electronic device, comprising: a display; a housing connected to the display; a strap connected to the housing; and an adjustable headband connected to the strap, the adjustable headband comprising: a band; a cable connected to the band; and a tensioning system connected to the band and the cable, the tensioning system comprising: a dial housing; a cam wheel in the dial housing, the cam wheel including a ramped surface defining a roller opening; a dial wheel including a protrusion extending into the roller opening; and a roller disposed in the roller opening adjacent the protrusion and between the ramped surface and the dial housing, the ramped surface being inclined relative to a line tangential to a point on the dial housing in contact with the roller.