Friction hinge for tablet computers

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Solution Overview

Problem

Existing kickstands for portable computing devices, such as tablets, offer limited discrete screen angles and are often coupled through a hinge that protrudes, which can restrict user experience and fail to maintain support under various usage loads and accidental overloads throughout the device's lifecycle.

Innovation Solution

A friction hinge mechanism with a band/shaft coupling and telescoping linkage that allows 180-degree rotation while maintaining a constant gap, providing sufficient torque to support usage and abuse loads, and featuring a wear plate to decouple wear resistance from ductility, along with customizable torque profiles using metal injection molding (MIM) technology for optimal strain energy and torque density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a traditional hinge is used to couple the kickstand to the tablet body, then the kickstand can be attached to the device, but the hinge protrudes from the device surface and limits user experience

Engineering Contradiction:

ImproveprofileVSAvoiduser experience

Core Design Contradiction:

ShapeVSEase of operation

Solution Approach 1:

The hinge assembly is nested within the tablet body profile. The kickstand rotates about a pivot point that is positioned such that the hinge mechanism remains concealed within the device thickness, allowing the kickstand to rotate between substantially coplanar and substantially perpendicular positions without protruding from the tablet surface.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Adaptability or versatility

If discrete angle positions are provided in the kickstand, then the structure is simple, but the screen angle adjustability is limited

Engineering Contradiction:

Improvescreen angle adjustabilityVSAvoidkickstand structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The kickstand transitions from discrete angle positions to continuous angle adjustment capability. A spring mechanism applies variable torque to the rotating kickstand, with the spring force varying as the kickstand rotates between coplanar and perpendicular positions, enabling smooth continuous adjustment of the display angle rather than fixed discrete positions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The torque characteristic of the spring is varied as a function of the kickstand rotation angle. The spring is configured to provide different torque values at different angular positions, creating a torque profile that facilitates easy rotation through most of the range while providing increased resistance near the extremes, enabling continuous adjustability without requiring complex control mechanisms.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a friction hinge is used to support various usage loads, then the kickstand can maintain position, but wear accumulates over the device lifecycle

Engineering Contradiction:

Improvesupport capabilityVSAvoiddevice lifecycle

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The traditional friction-based mechanical hinge is replaced with a magnetic field-based suspension system. Magnets positioned in the tablet body interact with magnets in the kickstand to provide contactless support and positioning forces, eliminating mechanical friction and wear while maintaining the ability to support various usage loads throughout the device lifecycle.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of operation

If the kickstand allows easy opening, then user operation is simple, but accidental overloads may damage the mechanism

Engineering Contradiction:

Improveopening easeVSAvoidoverload resistance

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The spring mechanism is pre-configured to provide increasing torque resistance as the kickstand approaches perpendicular position. This preliminary anti-action means that while the kickstand can be easily opened from coplanar positions, the spring torque increases progressively to prevent excessive force from being applied that could damage the mechanism or detach the kickstand, thereby protecting against accidental overloads.

Inventive Principle:

Principle #9Preliminary anti-action

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

Enhances user experience by providing continuous adjustability of screen angles, supports usage and accidental loads, and maintains performance over the device's lifecycle with reduced wear and increased torque density, while minimizing the need for additional mechanisms or complexity.

Implementation Method 1

a friction band, which is configured to substantially surround the friction shaft

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

a spring, which is configured to substantially surround the friction shaft and the telescoping link

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9549479B2Friction hinge for tablet computers

Publication Date: 2017.01.17 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Technologies are generally described for a kickstand or similar support device connection mechanism in conjunction with computing devices. A substantially constant gap may be maintained between the kickstand and the device enclosure across the hinge rotation spectrum allowing the hinge and/or the kickstand to be level with the device enclosure. The connection mechanism may support various usage loads and rotation angles up to about 180 degrees, as well as allow for low force opening to a first position.