Foldable Terminal Hinge Cam Structure for Stable Ejection Angle
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Solution Overview
Problem
The stability of the ejecting angle in hinge mechanisms of foldable terminal devices is compromised due to large deformation amplitudes and reaction forces in torsion springs, leading to reduced elasticity and service life, affecting the stability of the unfolding process.
Innovation Solution
A hinge mechanism with a swing arm assembly and a cam structure that includes a bearing member, swing arms, and gears, where an elastic piece applies force to ensure controlled deformation, and a cam structure provides synchronized rotation and reduced reaction forces, enhancing the stability of the ejecting angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a torsion spring is used in the hinge mechanism to eject the terminal device after unlocking, then the terminal device can be automatically ejected to an angle, but the large deformation amplitude and reaction force reduce the service life and stability of the torsion spring
Solution Approach 1:
The patent divides the ejection function into two parts: a torsion spring provides initial ejection force to overcome gravity and unlock the device, while a cam structure takes over to complete the ejection motion and maintain the ejection angle. This segmentation reduces the deformation amplitude and reaction force on the torsion spring, thereby extending its service life while maintaining reliable automatic ejection.
Solution Approach 2:
The cam structure acts as an intermediary between the torsion spring and the swing arm assembly. The torsion spring applies force to the cam, which then converts this force into controlled ejection motion through its geometric profile. This intermediary mechanism reduces the direct reaction force on the torsion spring while ensuring stable ejection angle maintenance.
2Force
If a torsion spring with large deformation amplitude is used to provide ejection force, then the ejection function is achieved, but the elasticity of the torsion spring weakens over time affecting ejection angle stability
Solution Approach 1:
The patent changes the operational parameters of the elastic component by introducing a cam structure with specific geometric parameters. The cam's profile is designed to convert the torsion spring's rotational motion into controlled linear ejection motion, maintaining consistent ejection angle while reducing the torsion spring's deformation amplitude. This parameter optimization preserves the ejection force while improving angle stability over time.
3Length of moving object
If the bearing member is positioned far from the gear, then the elastic force can be applied, but the ejection force is insufficient to drive the swing arm to rotate toward the unfolding position
Solution Approach 1:
The patent employs a cam structure with a curved profile that converts the elastic force into an optimized ejection force. The cam's geometric curvature is designed to amplify the force transmission from the bearing member to the gear, ensuring sufficient ejection force is generated even when the bearing member is positioned at an optimal distance from the gear. This curved mechanism efficiently transforms force magnitude and direction.
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 cam structure stabilizes the ejecting angle by controlling deformation amplitude and reaction forces, prolonging the life of the elastic components and ensuring consistent ejection, thereby maintaining the stability of the terminal device in both folded and unfolded states.
Implementation Method 1
The elastic piece is configured to apply an elastic force to at least one of the bearing member and the gear for the bearing member to be close to the gear
Implementation Method 2
The first cam structure is disposed between a first end face of the gear and the bearing member, and includes a first protrusion part disposed on one of the bearing member and the first end face, and a second protrusion part disposed on the other of the bearing member and the first end face
Data Source
AI summary
A hinge mechanism includes a base, a swing arm assembly, an elastic piece, and a first cam structure. The swing arm assembly includes a bearing member, a pair of swing arms, and an even number of gears. The even number of gears are in transmission connection between the pair of swing arms, and the bearing member is fastened to the base in an axial direction relative to the gears. An elastic piece is configured to apply an elastic force to the bearing member and/or the gears. A first cam structure is disposed between first end faces of the gears and the bearing member, and includes a first protrusion part and a second protrusion part disposed on the bearing member and/or the first end faces.