Electronic Keyboard Pedal Shaft Positioning for Accurate Depression Sensing

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Solution Overview

Problem

Existing pedal devices for electronic keyboard instruments lack a stable and uniform mechanism for detecting the depressing amount of pedals, leading to inconsistent operation feelings and limited functionality in detecting varying pedal depression levels.

Innovation Solution

A pedal device with a rotary volume and engagement member that ensures precise positioning of the rotational shaft, coupled with a sensor unit to accurately detect the depressing amount of pedals, providing a uniform operation feeling and enabling functions like damper effects based on the depression level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional sensor with a lever portion is used to detect pedal depression, then the pedal depressing amount can be detected, but the operation feeling becomes inconsistent and unstable

Engineering Contradiction:

Improvepedal depression detection accuracyVSAvoidoperation feeling consistency

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the conventional mechanical lever-based sensor with a rotary encoder that uses a rotational shaft and engagement member mechanism. This substitution provides more stable and precise detection of pedal depression amounts, eliminating the inconsistency issues associated with lever-based mechanical sensors while maintaining accurate measurement capabilities.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a rotary volume with rotational shaft is used to detect pedal depression, then measurement precision improves, but the positioning stability of the rotational shaft becomes problematic

Engineering Contradiction:

Improvepedal depression detection accuracyVSAvoidrotational shaft positioning stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent introduces an engagement member as an intermediary component between the rotational shaft and the base plate. This engagement member includes an engagement portion that fits into a groove on the rotational shaft and another portion that engages with the base plate, thereby stabilizing the rotational shaft's positioning while allowing it to rotate smoothly for accurate depression detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If the rotational shaft is directly engaged with the base plate, then the construction is simple, but the positioning precision and stability are insufficient

Engineering Contradiction:

Improveconstruction simplicityVSAvoidrotational shaft positioning precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent divides the engagement mechanism into distinct segments: the rotational shaft with its groove, the engagement member with its engagement portions, and the base plate with its corresponding engagement feature. This segmentation allows each component to be manufactured separately with precise tolerances while maintaining overall construction simplicity and achieving high positioning precision through the interlocking engagement portions.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12412549B2Pedal device and electronic keyboard instrument

Publication Date: 2025.09.09 CASIO COMPUTER CO LTD

AI summary

A pedal device includes a base plate, a pedal supported rotatably, a rotary volume comprising a rotational shaft configured to rotate in association with the pedal, and an engagement member configured to be brought into engagement with a non-rotational portion provided around the rotational shaft of the rotary volume and with the base plate.