Braille Pin Actuation Using Cam Mechanism and Angular Position Sensing

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Solution Overview

Problem

Conventional refreshable braille displays face challenges in the design and actuation of braille cells, particularly in efficiently moving pins to form different braille characters for tactile reading by blind and visually impaired individuals.

Innovation Solution

A braille cell design incorporating a frame with apertures, braille pins, pin actuation assemblies, and support arms, where the pins are moved between raised and lowered positions using a motor-driven cam system with an angular position sensing system to achieve distinct braille configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional piezoelectric actuators are used to move braille pins, then pin actuation is achieved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvepin actuationVSAvoidactuation mechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces complex piezoelectric actuators with a simpler cam-based mechanical system. The cam mechanism converts rotational motion from a motor into the linear up-and-down motion required for pin actuation, eliminating the need for complex piezoelectric elements while achieving the same functional result.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The braille display is divided into multiple braille cells, each with its own simplified actuation mechanism. This segmentation allows each cell to be independently controlled with a straightforward cam-based system rather than requiring a complex centralized actuation mechanism.

Inventive Principle:

Principle #1Segmentation

2Productivity

If multiple pins are moved simultaneously to form braille characters, then reading efficiency improves, but control precision and synchronization become more difficult

Engineering Contradiction:

Improvebraille character formation speedVSAvoidpin position control accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The cam mechanism is designed to follow a periodic cycle that sequentially raises and lowers pins in a predetermined pattern. This periodic motion ensures that multiple pins are actuated in precise synchronization, with each pin reaching its target position at the correct time in the cycle, thereby maintaining positional accuracy while achieving rapid character formation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system incorporates sensors that detect the position of each pin and provide feedback to the control system. This feedback mechanism allows the controller to monitor and adjust pin positions in real-time, ensuring precise control even when multiple pins are actuated simultaneously or in rapid succession.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If braille pins are frequently moved between raised and lowered positions to refresh display, then display adaptability improves, but mechanical wear and reliability issues increase

Engineering Contradiction:

Improvedisplay refresh capabilityVSAvoidpin mechanism durability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The cam mechanism is designed with cushioning features that reduce impact forces when pins make contact or return to their rest position. This cushioning effect absorbs shock and reduces mechanical stress on the pin and support structures, thereby extending the life of the mechanism despite frequent actuation cycles required for display refresh.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The system uses curved support arms with specific geometric profiles that change the motion parameters of the pins during actuation. The curved geometry provides a smoother acceleration and deceleration profile, reducing mechanical shocks and wear compared to linear actuation, thereby improving reliability while maintaining refresh capability.

Inventive Principle:

Principle #35Parameter changes

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

This design enables precise and reliable tactile representation of braille characters, enhancing the reading experience for visually impaired individuals by ensuring accurate and efficient pin movement and configuration.

Implementation Method 1

a pin actuation assembly configured to move each braille pin between the raised position and the lowered position thereof

Methodology Applied

Scientific EffectCam mechanism: Cam

Data Source

PatentUS11455910B2Braille cell and associated pin support and pin actuation assemblies

Publication Date: 2022.09.27 TECH HUMANWARE

AI summary

A braille cell and associated braille pin support and pin actuation assemblies are disclosed. The braille cell can include a frame, braille pins movable up and down between raised and lowered positions, and a pin actuation assembly to individually move the pins. The braille cell can include support arms, each of which having a base end connected to the frame and a pin end connected to and following a motion of a respective pin between its raised and lowered positions. The pin actuation assembly can include pin actuation units, each having a motor with a rotatable motor shaft and multiple cams mounted on the shaft, each for selectively actuating a respective pin. Each pin actuation unit can also include an angular position sensing system for monitoring, for example magnetically, a passage of the shaft through a reference angular position, and deriving information about a current angular position of the shaft.