Grand Piano Action Jack Weight Reduction via Wippen-Integrated Adjustment
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Solution Overview
Problem
Existing grand piano mechanisms face limitations in reducing the weight of both the jack and wippen while maintaining sufficient string striking repeatability, as adding adjustment mechanisms increases inertial force and weight, affecting the ability to repeatedly strike strings.
Innovation Solution
A grand piano action featuring a wippen made of synthetic resin with a jack angular position-adjusting mechanism integrated into the wippen, using an adjustment screw and abutment portion to adjust the jack's angular position without adding weight to the jack, thereby reducing the overall weight of both the jack and wippen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the adjustment mechanism is provided on the jack, then the angular position of the jack can be adjusted, but the weight of the jack increases
Solution Approach 1:
The adjustment mechanism is extracted from the jack and relocated to the wippen. The adjustment screw is now provided on the wippen instead of the jack, allowing the jack to be lighter while still enabling angular position adjustment through the wippen-based mechanism.
2Weight of moving object
If the adjustment mechanism is provided on the wippen, then the weight of the jack can be reduced, but the weight of the wippen increases
Solution Approach 1:
The wippen is made of synthetic resin material which is lighter than traditional metal, while the adjustment screw is made of metal and localized to specific areas where strength is needed. This local differentiation of material properties allows weight reduction overall while maintaining necessary structural integrity.
3Strength
If a metal rod is used for the stop screw, then sufficient strength is achieved, but the weight of the wippen increases
Solution Approach 1:
The wippen is constructed using synthetic resin material which provides sufficient strength for the application while being significantly lighter than metal. The adjustment screw is made of metal only where structural integrity is critical, creating a composite structure that optimizes the strength-to-weight ratio.
Data Source
AI summary
An action of a grand piano, which makes it possible to reduce not only the weight of a jack, but also that of a wippen, to thereby improve string striking repeatability. The action includes a wippen of a synthetic resin configured to pivotally move upward by being pushed up by the depressed key, a jack pivotally mounted to the wippen, for pushing up the hammer in accordance with pivotal motion of the wippen to cause the hammer to pivotally move upward, and a jack angular position-adjusting mechanism provided on the wippen to adjust an angular position of the jack. The mechanism has a support portion integrally formed with the wippen, an adjustment screw screwed into the support portion movably in a front-rear direction, and a jack button provided on an end of the adjustment screw for defining the angular position of the jack by abutment therewith.