Hinge Assembly with Friction Washer for Stable Torque
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Solution Overview
Problem
Existing hinge assemblies for tablet computers experience unstable frictional torque due to wear between the eccentric extension member and pivot shaft, leading to irregular application forces required to adjust the kickstand's angle.
Innovation Solution
A hinge assembly design featuring a first hinge unit, a guiding unit, and a second hinge unit with a pivot shaft, a first ring, a second ring, friction washers, a protrusion-and-groove arrangement, and resilient washers, which provide stable torsional force by varying frictional resistance through the movement of the second hinge unit between folded and unfolded states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an eccentric extension member is used to generate torsional force, then the application force varies with the angle between the kickstand and main body, but the friction torque becomes unstable due to wear between the eccentric extension member and pivot shaft
Solution Approach 1:
The hinge assembly is divided into multiple independent components: a first hinge unit, a guiding unit, and a second hinge unit. This segmentation allows each component to perform its specific function independently, with the second hinge unit specifically designed to manage the friction torque generation through separate elements (eccentric extension member, friction washer, resilient washer) that can be maintained separately.
Solution Approach 2:
A friction washer is introduced as an intermediary element between the eccentric extension member and the pivot shaft. This friction washer serves as a dedicated component that generates the necessary friction torque while being replaceable and maintainable, thus stabilizing the friction torque despite wear over time.
Solution Approach 3:
The hinge assembly utilizes changes in geometric parameters (the angle between the kickstand and main body) to vary the application force requirements. The eccentric extension member's position changes with the angle, creating variable torsional force that adapts to different kickstand positions.
2Power
If no clearance exists between the eccentric extension member and pivot shaft, then the torsional force is generated effectively, but wear occurs leading to unstable friction torque over time
Solution Approach 1:
The friction washer is designed as a consumable component that can be replaced after wear occurs. This allows the hinge assembly to maintain stable friction torque over extended periods by periodically replacing the worn friction washer, effectively extending the service life of the overall mechanism.
Solution Approach 2:
The resilient washer is positioned to provide preliminary cushioning and maintain consistent contact pressure between the friction washer and the pivot shaft. This ensures that the friction torque remains stable even as the friction washer wears, by compensating for dimensional changes through elastic deformation.
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 design ensures a stable and consistent application force is required to adjust the kickstand's angle, maintaining functionality over time by providing a controlled and varying frictional torque.
Implementation Method 1
at least one resilient washer sleeved on the pivot shaft to resiliently push the at least one friction washer against the third contact surface
Implementation Method 2
The least one friction washer is fitted around the pivot shaft and abuts a third contact surface of the second ring opposite to the second contact surface
Data Source
AI summary
A hinge assembly includes a guiding unit connected between and slidable relative to first and second hinge units along arcuate lines. The second hinge unit has a pivot shaft extending through first and second rings, and a resilient washer. The second ring is rotatable on the pivot shaft relative to the first ring and has a radial extension member telescopically connected to a pivotal arm of the first hinge unit. The resilient washer pushes the second ring against the first ring. A protrusion of the first ring slides along a contact surface of the second ring having a groove so that a variable friction toque is created against relative movement of the first and second hinge units.