Adjustable Friction Hinge Radial Compression Mechanism
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Solution Overview
Problem
Existing friction hinges require significant tightening force to generate sufficient friction, compromising appearance and consistency in frictional force, particularly in designs with axial screws and straps.
Innovation Solution
An adjustable friction hinge with a threaded compression nut and unthreaded bushing system, utilizing beveled friction bushings and a barrel bushing with angled ends to increase contact surface and generate consistent frictional force without the need for extensive screw tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a tightenable axial screw is used to compress knuckles together, then frictional force is increased, but significant tightening force is required and the appearance is compromised
Solution Approach 1:
A compression nut is introduced as an intermediary component between the screw and the knuckles. The compression nut converts the linear compression force from the screw into radial outward force that pushes against the knuckles, eliminating the need for the knuckles to move closer together and reducing the tightening force required.
Solution Approach 2:
Instead of compressing the knuckles together by moving them closer (axial compression), the invention inverts the approach by using a compression nut to push the knuckles outward radially. This inversion of the compression direction eliminates the need for significant tightening force while maintaining the frictional force.
2Force
If flat washers are used between knuckles, then friction is increased, but considerable tightening force is still required
Solution Approach 1:
The invention replaces flat washers with spherical or curved friction surfaces on the knuckles. The spherical friction surfaces allow for more efficient force distribution and contact, increasing frictional force while requiring less tightening force compared to flat washers.
3Force
If a strap with screw is used to increase friction, then sufficient frictional force is generated, but the appearance is compromised and the design is bulky
Solution Approach 1:
The invention extracts and eliminates the bulky strap component from the hinge design. By using a compression nut and spherical friction surfaces, the frictional force is generated without requiring the additional strap element, resulting in a streamlined appearance while maintaining sufficient frictional force.
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 adjustable and consistent frictional force between hinge components, enhancing appearance and reducing the required tightening force, while maintaining a streamlined design.
Implementation Method 1
utilizing beveled friction bushings and a barrel bushing with angled ends to increase contact surface and generate consistent frictional force
Data Source
AI summary
An adjustable friction hinge with a first hinge portion with two spaced apart first hinge knuckles and second hinge portion having a second hinge knuckle with rotatably fit together. A barrel bushing is non-rotatably positioned in the second hinge knuckle. A friction bushing is slidably and non-rotatably located in openings in the two first hinge knuckles. A threaded compression nut, and a non-threaded compression nut are located in the two spaced apart first hinge knuckles. A screw passes through the non-threaded compression nut, the spaced apart first hinge knuckles, the second hinge knuckle, the two friction bushings, and into the threaded compression nut. When the screw is tightened, the threaded and non-threaded compression nuts force the two frictional bushing into frictional contact with the barrel bushing to increase a force required to move the first hinge portion and the second hinge portion relative to each other.