Modular Upright Piano Hammer Return Spring Rail With Adjustable Tension

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Solution Overview

Problem

Conventional hammer return spring rails for upright pianos are cumbersome to manufacture and cannot be adjusted in length or distance between springs, and existing repetition springs are not easily adjustable, while pedal assemblies lack flexibility in upright pianos.

Innovation Solution

A modular hammer return spring rail with adjustable torsion springs and a repetition spring assembly featuring a torsion spring with adjustable connection points, allowing for easy tension adjustment using screws or other tools, and a pedal assembly with a rotating bar for upright pianos.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a traditional non-modular hammer return spring rail is used, then the structural integrity and hammer return function are maintained, but the complexity of assembly and repair increases due to the integrated design

Engineering Contradiction:
Improveassembly easeVSAvoidstructural complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The hammer return spring rail is divided into multiple modular segments that can be independently manufactured, assembled, and replaced. Each segment contains specific hammers and corresponding return springs, allowing for localized maintenance and simplified assembly procedures while maintaining the overall structural integrity of the piano action mechanism.

Inventive Principle:
Principle #1Segmentation

2Ease of repair

If a traditional integrated hammer return spring rail is used, then the hammer return function is maintained, but the time required for repair and maintenance increases

Engineering Contradiction:
Improvemaintenance easeVSAvoidmaintenance time
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The modular segmentation allows technicians to access and replace only the specific segment containing the problematic hammer or spring, rather than disassembling the entire rail assembly. This significantly reduces maintenance time and simplifies repair procedures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Individual hammers and return springs are designed as extractable components that can be removed from their respective segments without affecting other parts of the system. This extraction capability enables quick replacement of worn or damaged components during maintenance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If a non-modular hammer return spring rail is used, then the overall structure is simplified, but the adaptability for different hammer configurations is reduced

Engineering Contradiction:
Improveconfiguration adaptabilityVSAvoidmodular complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Each modular segment is designed with standardized interfaces and mounting mechanisms that accommodate different hammer types and configurations. This segmentation enables the piano builder to mix and match segments to create custom hammer configurations while maintaining structural consistency through the modular framework.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The modular segments are designed with universal mounting features and standardized dimensions that allow them to be used in various positions and configurations within the piano action. This universality provides adaptability for different hammer arrangements while using the same basic segment design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The solution enables easy adjustment of spring tension and length, facilitates modular assembly, and enhances the flexibility of pedal mechanisms, improving the performance and customization of upright pianos.

Implementation Method 1

a return spring positioned underneath the hammer shank and engaged by the hammer shank in the forward position. The return spring is compressed by the hammer shank when the hammer shank is in the forward position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4381497B1Hammer return spring rail for an upright piano, modular hammer return spring rail for an upright piano, repetition spring assembly for an upright piano, and pedal assembly for an upright piano
Publication Date: 2026.05.06 1052 QUEBEC INC
  • EP4381497B1 patent drawingFigure 1~2
  • EP4381497B1 patent drawingFigure 3~7
  • EP4381497B1 patent drawingFigure 8~10

AI summary

A hammer return spring rail (10) for an upright piano including: at least one cavity (15) for receiving at least one rod (20); and a plurality of open compartments (25) each configured to receive a hammer return spring (30), each spring (30) including a coil (35), and each compartment (25) allowing the hammer return spring (30) to extend outward therefrom in a generally downward direction; each compartment (25) including a slot (45) for receiving an extension (40) of each hammer return spring (30); and each compartment including an aperture (50) for receiving an adjusting means (55) such that, by adjusting the degree to which the adjusting means (55) are inserted into the aperture (50), pressure applied to the extension (40) of the spring (30) can be increased or decreased, thereby causing an increase or decrease of the force exerted by the spring (30) on a corresponding hammer butt (60).