Lightweight Stringed Keyboard Structure for Portable Acoustic Pianos
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Solution Overview
Problem
Acoustic pianos are heavy, difficult to transport, and consume significant space due to their construction, which includes a cast metal front plate and massive wood frames, limiting their portability and affordability.
Innovation Solution
A lightweight sound-body construction using high-modulus materials like steel for the front and back plates, combined with soundboard fixation layers and a sandwich structure, optimized with a side plate and bridge design to enhance sound reflection and reduce weight, along with a foldable action mechanism for separate transportation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cast metal front plate and massive wood frame are used, then the structural strength and sound reflection are improved, but the weight increases significantly
Solution Approach 1:
The patent employs composite materials throughout the structure: the front plate uses a composite of metal framework and fiber-reinforced plastic, the soundboard combines wood with fiber-reinforced plastic reinforcement, and the back frame uses composite construction. These composite materials provide the necessary structural strength while significantly reducing weight compared to traditional solid metal and wood construction.
Solution Approach 2:
The patent applies local quality by reinforcing specific areas with fiber-reinforced plastic where structural strength is needed (front plate framework, soundboard ribs, back frame) while leaving other areas lighter. The fiber-reinforced plastic is strategically placed to provide localized strength enhancement without adding unnecessary weight throughout the entire structure.
2Stability of the object's composition
If a cast metal front plate and massive wood frame are used, then the structural stability is improved, but the portability deteriorates
Solution Approach 1:
The composite construction using fiber-reinforced plastic combined with metal frameworks provides high structural stability with reduced weight. This enables the piano to maintain its structural integrity while being light enough for portable operation, directly resolving the contradiction between stability and portability.
Solution Approach 2:
The patent changes the material parameters from dense traditional materials (solid cast metal, massive wood) to lighter composite materials with equivalent or superior mechanical properties. This parameter change in material density and strength-to-weight ratio enables both structural stability and improved portability.
3Ease of manufacture
If traditional soundboard fixation methods are used, then the manufacturing simplicity is maintained, but the acoustic quality deteriorates due to vibration absorption
Solution Approach 1:
The patent applies local quality by using different materials for different functions: a softer soundboard material for vibration and sound production, and a harder fiber-reinforced plastic fixation layer for structural support. This localized material differentiation maintains manufacturing simplicity while improving acoustic quality by preventing excessive vibration absorption at the fixation points.
Solution Approach 2:
The composite construction of the soundboard, combining wood with a fiber-reinforced plastic fixation layer, resolves the contradiction by using materials with complementary properties: the wood provides acoustic quality and vibration characteristics, while the fiber-reinforced plastic provides structural support with controlled vibration absorption.
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 results in a significantly lighter and more portable acoustic piano, reducing weight by up to 30% and space requirements, while maintaining acoustic sound quality, suitable for urban lifestyles and flexible handling.
Implementation Method 1
their natural ability to reflect soundboard vibrations back into the soundboard, thus not absorbing them
Implementation Method 2
capable of prohibiting relative movement between front plate and back plate, with said back plate being constituted of a material comparable to the front plate, preferably thinner than said front plate and dimensioned with a minimal amount of material located behind the outer edge portion of the soundboard to reach an optimal sandwich principle effect together with the front plate, to optimize bending resistance
Implementation Method 3
said front plate being bonded to a soundboard fixation layer constituted of a material with a hardness comparable to or higher than birch
Data Source
AI summary
A transportable stringed keyboard instrument includes a lightweight sound-body formed of several layers with front plate and back plate of material of high modulus of elasticity like steel or higher, with a side plate of a material of high modulus of elasticity like steel or higher, bonded to various layers between front plate and back plate. A method of forming a lightweight sound-body includes a single press procedure, wherein the sound-body is formed with bending in opposite direction compared to bending forces due to the string load. An upright piano action is optimized for space reduction so that keys can be positioned closer to the strings and a rotatable action together with the keys form a separate unit for transportation, apart from the sound-body.