Adjustable Capstan Mechanism for Electric Piano Key Regulation
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Solution Overview
Problem
Conventional electric piano designs, such as the Rhodes, lack the ability to adjust individual key dip, hammer height, and escapement distance, leading to inconsistencies in tone production due to the tapered balance rail and fixed fulcrum positions, resulting in varying hammer heights and escapement distances across natural and sharp keys.
Innovation Solution
The introduction of adjustable top and bottom capstans and a longitudinally movable hammer jack allows for individual adjustments of key dip, hammer throw, and escapement distance, enabling optimal tone regulation and user preference customization by rotating and positioning these components to align keys and standardize hammer positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed fulcrum position and solid pedestal design are used, then the structure is simple and robust, but individual key dip and hammer height cannot be adjusted, leading to tone inconsistencies
Solution Approach 1:
The patent applies the dynamics principle by making the fulcrum position adjustable rather than fixed. The fulcrum can be repositioned along the keystick to compensate for variations in key dip and hammer height, allowing each key to be individually regulated for optimal tone production while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent applies the local quality principle by allowing different parts of the action mechanism to have different properties. Specifically, the fulcrum position can be locally adjusted for each key or group of keys to compensate for manufacturing tolerances and wear, while the overall structure remains standardized and simple.
2Reliability
If the hammer cam directly contacts the pedestal end, then the mechanism is simple, but the stop-lock position and escapement distance cannot be regulated, causing hammer bounce and muted tone
Solution Approach 1:
The patent introduces an intermediary component (the adjustable fulcrum mechanism) between the hammer cam and pedestal end. This intermediary allows for regulation of the stop-lock position and escapement distance, ensuring reliable tone production by preventing hammer bounce while adding only minimal complexity to the mechanism.
3Ease of manufacture
If natural and sharp keys share the same fulcrum position, then manufacturing is simplified, but hammer heights vary due to the tapered balance rail, resulting in inconsistent escapement distances
Solution Approach 1:
The patent applies the parameter changes principle by making the fulcrum position variable rather than fixed. This allows the fulcrum to be repositioned to compensate for the tapered balance rail geometry, ensuring that both natural and sharp keys achieve consistent hammer heights and escapement distances while maintaining relatively simple manufacturing processes.
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 solution enables precise regulation of each key's action, ensuring consistent tone production and preventing issues like hammer bounce and double striking, by allowing for tailored adjustments of key dip, hammer throw, and escapement distance, thereby enhancing the overall performance and feel of the electric piano.
Implementation Method 1
Due to pressure applied between the rear of the pedestal and the hammer cam, a brake effect is applied to the hammer at the end of a key stroke.
Implementation Method 2
a top capstan extending vertically upward from the pedestal end of the keystick and having a surface contacting a brake portion of the hammer cam surface in the stop-lock position; a hammer jack extending from a top surface of the key stick inboard of the top capstan and contacting a cam portion of the hammer cam surface in the rest position
Data Source
AI summary
An adjustable action for an electric piano is provided with a keystick having an adjustable bottom capstan at an end thereof opposite the key, which is adjustable so that the rest position of the hammer of each such key may be independently adjusted, and an adjustable top capstan and hammer jack on the top of the keystick, which may be adjusted so that the stop-lock (depressed key) position of the hammer of each such key may be independently adjusted.