Foldable Hinge Cam Locking for Thin Freestop Devices
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Solution Overview
Problem
Existing folding display phones achieve the freestop characteristic by increasing the number and size of springs, which increases the device's thickness and weight, contradicting the goal of a thin body design.
Innovation Solution
A foldable electronic device with a shaft cap, body, swing arm, first and second cam components, and an elastomer, where the cam components have matching cam surfaces with a locking section angle less than or equal to arctan μ, ensuring a friction coefficient balance to maintain the freestop characteristic without increasing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the quantity and size of springs are increased to achieve freestop characteristic, then the friction coefficient increases, but the overall thickness and weight of the device increase
Solution Approach 1:
The patent changes the geometric parameters of the cam components, specifically designing the cam surface with a locking section where the angle between the normal direction and the central shaft is less than or equal to arctan μ. This parameter optimization allows the friction force to sufficiently hold the device in position without requiring additional springs, thereby achieving freestop characteristic without increasing device weight.
2Reliability
If the quantity and size of springs are increased to achieve freestop characteristic, then the friction coefficient increases, but the overall thickness of the device increases
Solution Approach 1:
The patent optimizes the cam surface geometry by controlling the angle of the locking section to be less than or equal to arctan μ. This parameter change enables the existing spring structure to generate sufficient friction force for freestop function without requiring additional space for larger or more springs, thus maintaining thin device profile.
Solution Approach 2:
The patent employs curved cam surfaces with specifically designed geometry. The cam surface includes a locking section with controlled angular orientation, utilizing curved surface geometry to optimize force distribution and friction characteristics, achieving freestop function without increasing device thickness.
3Reliability
If the cam surface angle is optimized to balance friction forces, then the freestop characteristic is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The cam surface geometry is designed to utilize the inherent friction properties of the materials and the natural elastic force of the existing spring. The locking section angle of less than or equal to arctan μ creates a self-balancing friction mechanism that automatically achieves freestop characteristic without requiring active control or high-precision adjustment 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 solution allows for a freestop characteristic while maintaining a thin body by optimizing the cam component interaction to balance friction forces, enhancing service life and user experience.
Implementation Method 1
The elastomer is connected to the second cam component and is configured to apply an elastic force to the second cam component
Implementation Method 2
The damping force is provided by a friction force generated by surface design of the cam component and the pressure contact
Data Source
AI summary
Embodiments of this application provide a foldable electronic device, including: a shaft cap, a body, a first cam component, and a second cam component. The first cam component and the second cam component come into pressure contact. The first cam component is configured to be rotatable around a central shaft of the first cam component. The second cam component is configured to be slidable along a direction of the central shaft. A contact surface of the first cam component and the second cam component includes a locking section, an angle between a normal direction of the locking section and the central shaft is less than or equal to a preset value, and a resultant force of a cam driving member in a rotation direction of the cam driving member is o, so that the body is not automatically unfolded or folded, thereby implementing the freestop characteristic.