Recoil Starter Ratchet Guide Anti-Swing Design
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Solution Overview
Problem
Recoil starters face issues with the ratchet mechanism being unintentionally moved and damaged due to vibrations, leading to unreliable engagement and disengagement with the driving pulley, which affects the engine starting process.
Innovation Solution
A recoil starter design featuring a ratchet guide with a guide portion that pushes the ratchet member to the outer diameter direction during engine starting and a swinging-prevention portion that prevents unintended swinging, combined with a friction spring for rotational resistance, ensuring the ratchet remains in a retracted position when the rope reel rotates opposite to the engine starting direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring is used to retract the ratchet to the inner diameter direction, then the ratchet can be returned to the retracted position after the recoil rope is released, but the ratchet may still be unintentionally moved by vibration or external forces
Solution Approach 1:
The ratchet guide structure proactively prevents unintentional ratchet movement by designing the swinging-prevention portion to block the ratchet's swing path before vibration or external forces can cause damage. This preliminary protective action occurs continuously regardless of whether the engine is running, preventing the harmful effect before it can manifest.
Solution Approach 2:
The ratchet guide acts as a protective structure that cushions against unintended ratchet movement. The swinging-prevention portion serves as a mechanical barrier that absorbs and redirects forces that would otherwise cause the ratchet to swing unintentionally, protecting the ratchet mechanism from damage before the damage can occur.
2Reliability
If the ratchet guide is made more robust to prevent unintended swinging, then the ratchet position stability improves, but the device complexity increases
Solution Approach 1:
The ratchet guide structure performs multiple functions simultaneously: it guides the ratchet member during engagement, prevents unintended swinging through the swinging-prevention portion, and maintains structural integrity. By consolidating these functions into a single component rather than adding separate mechanisms, the design achieves high reliability without proportionally increasing device complexity.
Solution Approach 2:
The guide portion and swinging-prevention portion are merged into a single integrated ratchet guide structure. This consolidation eliminates the need for separate components while achieving both the guidance function and the anti-swing function, thereby improving reliability without adding proportional complexity to the overall device.
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 configuration reliably holds the ratchet in a retracted position, reduces the free running distance, and strengthens the ratchet guide, preventing damage from unintentional forces and ensuring stable engagement with the driving pulley, thus improving the engine starting mechanism's reliability.
Implementation Method 1
a friction spring that provides the friction resistance to the ratchet guide
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
One aspect of the invention provides a recoil starter including: a reel support shaft; a rope reel that is rotatably mounted on the reel support shaft; a ratchet member that is swingably mounted on the rope reel; a ratchet guide that is rotatably mounted on the reel support shaft with friction resistance. The ratchet guide includes: a guide portion and a swinging-prevention portion. When the rope reel rotates in an engine starting direction, the guide portion pushes out the ratchet member to an outer diameter direction. When the ratchet member does not contact the guide portion, the swinging-prevention portion prevents the ratchet member from swinging to the outer diameter direction.