Segmented Piano String Frame with Under-String Strut
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Solution Overview
Problem
Conventional piano string frames made from cast iron are expensive, difficult to manufacture, and increasingly unavailable due to the decline of specialist foundries, requiring a solution that provides strength, stiffness, and minimal obstruction to piano strings while being cost-effective and widely available.
Innovation Solution
A piano string frame design featuring a frame plate with a perimeter aperture bisected by a strut and reinforced by beams, connected via welded joints, which eliminates the need for additional bars or struts above the strings, allowing for a strong, stiff, and stable structure with a large open space for improved piano performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional cast iron string frames are used, then strength and stability are achieved, but manufacturing cost increases and availability decreases
Solution Approach 1:
The string frame is divided into separate components (frame plate, beams, struts) that can be manufactured independently using standard steel fabrication processes, then assembled together. This segmentation allows each component to be made by widely available skills rather than requiring specialized cast iron foundries.
Solution Approach 2:
The patent replaces expensive, specialized cast iron components with cheaper, readily available steel materials that can be fabricated using common welding and metalworking processes. The focus is on achieving sufficient strength through design rather than using expensive materials.
2Strength
If cast iron string frames are used, then structural strength is provided, but manufacturing complexity increases
Solution Approach 1:
The frame is segmented into modular components (frame plate, beams, struts) that can be fabricated separately using simple cutting, bending, and welding operations, then assembled together. This eliminates the need for complex multi-stage casting processes while maintaining structural integrity.
Solution Approach 2:
The patent replaces the casting manufacturing system with a welding and assembly system. Instead of requiring specialized foundries to mold and heat-treat cast iron, the design uses standard steel fabrication and welding processes that are more widely available and simpler to implement.
3Strength
If additional bars or struts are added above strings for reinforcement, then strength and stiffness are improved, but open space for strings is reduced
Solution Approach 1:
The reinforcement structure is positioned in a different spatial dimension - the beams are attached to the sides of the frame plate while struts extend downward from the bottom edge, creating a three-dimensional reinforcement pattern that strengthens the frame without occupying horizontal space above the strings.
Solution Approach 2:
Instead of adding reinforcement elements above the strings (the conventional approach), the patent inverts the arrangement by positioning beams along the sides and struts extending downward, effectively moving the reinforcement structure to where it provides maximum strength with minimal obstruction to the strings.
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 design provides a strong, stiff, and stable piano string frame that supports high string tensions without deflection or buckling, enhances sound quality by reducing impedance and increasing space for mechanisms, and is cost-effective and easily manufacturable in the UK using widely available materials and skills.
Implementation Method 1
the first beam and the second beam are each connected to the frame plate via a welded joint
Data Source
AI summary
A piano string frame comprising a frame plate having a perimeter portion enclosing an aperture, and a strut bisecting the aperture. The perimeter portion has a bass pin portion to support a first end of a plurality of bass strings; a bass hitch portion to support a second end of a plurality of bass strings; a treble pin portion to support a first end of a plurality of treble strings; and a treble hitch portion. To support a second end of a plurality of treble strings. The strut extends from a first point to a second point. The second point is disposed at an end of the treble hitch portion to support a second end of a lowest pitched treble string, such that the strut is underneath any bass strings supported by the piano string frame, and such that no part of the frame plate is disposed over any strings.