Keyboard Device Pivot Adjustment and Universal Stopper Design
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Solution Overview
Problem
Conventional keyboard devices for electronic musical instruments require a large variety of components to achieve a key touch feeling and appearance similar to an acoustic piano, leading to high costs and low productivity due to the need for different pivot points and restricting members for each key pitch.
Innovation Solution
The keyboard device adjusts the position of the pivot point in the longitudinal direction and uses a single type of restricting member for all keys, with mass members that vary in weight from low to high pitches, allowing for a consistent key touch feeling and reduced component variety, enabling easier assembly and cost reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pivot point of each hammer is shifted in the longitudinal direction to achieve consistent key touch feeling, then the key touch feeling becomes uniform, but the position and thickness of the stopper must be different for each pitch, increasing component variety
Solution Approach 1:
The patent applies universality by making the stopper serve multiple functions: it restricts the rocking movement of hammers across all pitches and simultaneously acts as a positioning reference for the rubber switch. The stopper is positioned such that its tip aligns with the tip of the key in the key-released state, creating a universal reference point for all keys regardless of pitch. This allows a single type of stopper to be used for all pitches, reducing component variety while maintaining uniform key touch feeling.
Solution Approach 2:
The patent creates equipotentiality by positioning the tip of the stopper at the same longitudinal position relative to the tip of each key in the key-released state. This establishes an equipotential reference plane across all pitches, allowing the rubber switch to be positioned consistently for all keys. The stopper tip serves as an equipotential reference point that enables uniform switch positioning and consistent key touch feeling across all pitches without requiring pitch-specific components.
2Shape
If different positions and thicknesses of stopper are used for each pitch to maintain consistent key appearance, then the appearance similar to acoustic piano is achieved, but productivity decreases due to large variety of components
Solution Approach 1:
The stopper is designed as a universal component that performs multiple functions: restricting hammer rocking movement, positioning the rubber switch, and serving as a visual reference for key alignment. By making the stopper universal across all pitches, the patent eliminates the need for pitch-specific stoppers, thereby improving productivity while maintaining consistent key appearance through the standardized positioning of the stopper tip relative to each key tip.
Solution Approach 2:
The patent applies parameter changes by standardizing the longitudinal position of the stopper tip relative to the key tip across all pitches, rather than varying the stopper dimensions for each pitch. This parameter standardization allows a single stopper design to work for all pitches, improving productivity while maintaining consistent key appearance through the unified reference positioning established by the stopper tip alignment.
3Manufacturing precision
If the maximum depth during key depression is made the same for all keys, then consistent key response is achieved, but different stopper configurations are required for each pitch
Solution Approach 1:
The stopper is designed as a universal component that restricts the rocking movement of hammers for all pitches while maintaining consistent key depression depth. The stopper tip is positioned to align with the key tip in the key-released state, creating a universal reference that ensures consistent maximum depression depth across all pitches without requiring pitch-specific stopper configurations.
Solution Approach 2:
The stopper serves itself as a positioning reference for the rubber switch. By positioning the stopper tip at a consistent longitudinal position relative to each key tip, the stopper automatically establishes the correct positioning reference for the rubber switch, eliminating the need for separate positioning mechanisms for each pitch and ensuring consistent key depression depth.
Data Source
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AI summary
A keyboard device includes plural white and black keys 11w,11b that rock according to a key depression/release operation. Positions of key support portions 13w,13b supporting the plural white and black keys 11w,11b In the longitudinal direction are set to be different from one another. The keyboard device also includes hammers 16w,16b that rock with the rocking movement of the plural white and black keys 11w,11b. The plural white and black keys 11w,11b include drive units 11w1, 11b1 that drive the hammers 16w, 16b respectively. The pivot center of the hammer 16b is located posterior to the pivot center of the hammer 16w. An upper-limit stopper 21 and a lower-limit stopper 20, which restrict the rocking movement of the hammers 16w,16b are provided to extend in the lateral direction.