Slanting Joint Member for Stringed Instrument Neck Rigidity
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Solution Overview
Problem
Conventional bolt-on neck joint structures in stringed musical instruments lack mechanical rigidity and joint strength, leading to attenuated vibration and reduced sound quality and volume, as well as potential deviations in string-stretching direction and decreased durability.
Innovation Solution
A neck joint structure featuring a slanting joint member that screws into the body and neck via a recessed corner, ensuring the base-end portion of the neck is pressed in both thickness and longitudinal directions, enhancing mechanical rigidity and joint strength, while maintaining proper string-stretching alignment and preventing neck oscillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional bolt-on structure with joint screw is used, then manufacturability and manufacturing cost are improved, but mechanical rigidity and joint strength deteriorate
Solution Approach 1:
The joint screw is inclined at a specific angle (30-60 degrees) relative to the longitudinal direction of the neck, transitioning from a purely vertical or horizontal insertion to a diagonal dimension. This angular configuration allows the screw to engage simultaneously with the recessed end face and recessed bottom face, creating a three-dimensional locking mechanism that enhances joint strength while preserving the simplicity of the bolt-on structure.
Solution Approach 2:
The recessed structure is divided into two distinct faces: a recessed end face and a recessed bottom face, each serving a specific function. The recessed end face contacts the end face of the base-end portion, while the recessed bottom face contacts the main contact face. This segmentation allows the joint screw to create multiple contact points and force transmission paths, thereby improving joint strength without complicating the overall manufacturing process.
2Adaptability or versatility
If the joint screw is positioned obliquely, then movement capability in both thickness and longitudinal directions is improved, but joint strength deteriorates due to leverage effect
Solution Approach 1:
The recessed structure is strategically positioned at the base-end portion of the neck, creating a localized zone of enhanced constraint. This localized recessed structure specifically addresses the area most susceptible to leverage effects, providing targeted reinforcement without affecting the entire neck structure. The combination of the recessed structure's specific geometry and its precise location optimizes both movement control and strength.
3Ease of operation
If the base-end portion of the neck is not pressed in the longitudinal direction, then ease of assembly is improved, but vibration sustainability and sound quality deteriorate
Solution Approach 1:
By inclining the joint screw at 30-60 degrees, the force application transitions from a single vertical dimension to a multi-dimensional approach. This angular configuration naturally decomposes the pressing force into both vertical (thickness direction) and longitudinal components, ensuring simultaneous compression of the base-end portion against both the recessed end face and recessed bottom face. This multi-dimensional force application enhances vibration sustainability while remaining straightforward to assemble.
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 design improves mechanical rigidity and sound sustainability, maintains proper string-stretching state, and enhances durability by ensuring integral vibration of the body and neck, while preventing joint strength reduction and maintaining sound quality and volume.
Implementation Method 1
When an external force is applied to raise the neck along the upper surface of the body due to the 'leverage effect' about the support point at the base-end portion of the neck
Implementation Method 2
the joint member is a slanting joint member which is screwed into the body and the neck via the corner between the recessed bottom face and the recessed end face
Data Source
Figure 1
Figure 2
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AI summary
A neck joint structure which has an opening on the main face of a body in the thickness direction, which has openings on the side faces of the body extending in the thickness direction, and into which at least a part of the base-end portion of a neck is inserted is formed in the body of a stringed musical instrument. The neck joint structure includes a recessed end face which is brought into contact with the end face of the base-end portion constituting the base of the neck in the longitudinal direction and a recessed bottom face which is brought into contact with the main contact face of the base-end portion that forms a corner together with the end face in the thickness direction of the neck. The neck joint structure of the stringed musical instrument is equipped with a joint member fixing the body and the neck, i.e. a slanting joint member which is screwed into the body and the neck via the corner between the recessed bottom face and the recessed end face of the body and via the corner between the main contact face and the end face of the neck in the state in which the screwing direction thereof is slanted to the distal end of the neck in the longitudinal direction relative to the thickness direction of the body and the neck.