Cajon Hitting Assembly Lever Mechanism for Torsional Force
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Solution Overview
Problem
Conventional cajon hitting assemblies experience inadequate moving displacement and torsional force due to static friction between the drawing wire and wire tube, leading to a jammed feeling during performance, failing to meet the required use standards.
Innovation Solution
The cajon hitting assembly incorporates a lever mechanism using first and second struts to increase the moving displacement and instantaneous torsional force of the drawing wire, reducing static friction by positioning the wire tube ends on the upright posts with elastic elements and support bars to enhance smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the drawing wire is threaded through the wire tube to transmit force from foot pedal to hitter, then the hitting assembly can be operated, but static friction between drawing wire and wire tube causes inadequate torsional force and jammed feeling
Solution Approach 1:
The patent introduces an intermediary mechanism (the wire tube with elastic elements and support bars) between the drawing wire and the upright posts. This intermediary structure reduces direct friction contact by allowing the drawing wire to move more freely within the wire tube, thereby reducing static friction and improving smoothness of operation while maintaining adequate force transmission
Solution Approach 2:
The patent changes the physical parameters of the wire tube system by adding elastic elements and support bars, which modify the friction characteristics and mechanical advantage of the system. These parameter changes enable the drawing wire to experience reduced static friction while still transmitting adequate torsional force to the hitter
2Device complexity
If the foot pedal directly draws the drawing wire to drive the hitter, then the structure is simple, but the moving displacement is insufficient and torsional force is inadequate
Solution Approach 1:
The patent adds dimensional complexity to the force transmission path by introducing the wire tube with elastic elements and support bars. This creates additional degrees of freedom and mechanical advantage, allowing the foot pedal to generate sufficient torsional force through a more complex spatial arrangement rather than direct linear transmission
Solution Approach 2:
The patent introduces dynamic elements (elastic elements) into the wire tube system, allowing it to flex and store energy during operation. This dynamic behavior enhances the torsional force output while maintaining a relatively simple overall structure, resolving the contradiction between structural simplicity and force adequacy
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 ensures smoother movement and adequate force transmission, meeting the performance requirements by eliminating static friction and enhancing the lever action for efficient hitting of the cajon.
Implementation Method 1
the first and second struts can provide a lever function to increase the moving displacement of the drawing wire and enhance the instantaneous torsional force
Implementation Method 2
a static friction force generally takes place between the drawing wire and wire tube 3
Data Source
AI summary
A cajon hitting assembly comprises a foot pedal, a first upright post, a first strut, a wire tube, a second upright post, a second strut and a hitter. The wire tube is threaded by a drawing wire with a start end and a distal end. The first and second upright posts have respectively a first axle and a second axle. The foot pedal drives the first axle to turn. The first strut has two ends fastened respectively to the first axle and start end of the drawing wire. The second strut has two ends fastened respectively to the second axle and distal end of the drawing wire. The hitter is fastened to the second axle. When the foot pedal is treaded, the hitter is driven to hit the cajon. Through lever function provided by the first and second struts, moving displacement of the drawing wire increases.