Spring-Loaded Capo With Variable Lever Arm
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Solution Overview
Problem
Existing spring-loaded capos require excessive hand force to open and maintain open position, making it difficult to reposition them during a performance.
Innovation Solution
The capo design features a pivot mechanism where the path of spring force changes as the jaws open, reducing the lever arm and thus the opening force, allowing easier repositioning by decreasing the spring force required to keep the capo open.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a spring-loaded clamp mechanism is used to attach the capo to the instrument neck, then the capo can be rapidly opened and repositioned using one hand, but excessive hand force is required to open the capo and it is difficult to keep the capo open for repositioning
Solution Approach 1:
The patent applies the Dynamics principle by making the lever arm of the spring force variable rather than fixed. As the jaws open, the lever arm at which the spring acts decreases, causing the closing moment to decrease dynamically. This dynamic adjustment reduces the force required to open and hold the capo in the open position, directly resolving the technical contradiction between ease of repositioning and excessive opening force.
Solution Approach 2:
The patent employs the Parameter changes principle by altering the geometric parameter of the spring force path relative to the pivot point. Specifically, the mechanism is arranged so that the path of spring force changes with jaw position, moving closer to the pivot as the capo opens. This parameter change in the lever arm length modifies the mechanical advantage dynamically, reducing the force contradiction.
2Reliability
If the spring force path remains fixed with respect to the pivot, then the spring provides consistent closing force, but the opening force increases proportionally with spring compression making repositioning difficult
Solution Approach 1:
The patent transforms the static spring force application into a dynamic system where the lever arm changes with jaw position. This ensures that while the spring provides reliable closing force throughout the range of motion, the effective moment arm decreases as the capo opens, making it easier to keep the capo open for repositioning without sacrificing spring force consistency.
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 reduces the effort needed to open and reposition the capo, making it easier to use during performances by minimizing the increase in opening force relative to spring compression, enhancing practicality.
Implementation Method 1
spring force
Implementation Method 2
spring force
Implementation Method 3
constraining motion to be rotary
Implementation Method 4
lever arm at which the spring acts gets smaller as the jaws open
Implementation Method 5
The closing moment created by the spring force as the capo is opened is, therefore, less than it would have been had the path of the spring force remained fixed with respect to the pivot
Data Source
AI summary
A spring operated capo that includes two jaws with graspable handles and a spring that urges the two jaws to close on the neck of a stringed musical instrument. The spring exerts a force on the two jaws with a lever arm that decreases as the jaws open.