Cart Folding Joint Linkage Gear Unit Design
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Solution Overview
Problem
Baby strollers and golf trolleys with few gear teeth suffer from reduced contact ratio and increased bearing stress during folding and unfolding, leading to gear damage and limited design flexibility due to restricted included angles.
Innovation Solution
A cart design featuring a folding joint mechanism with a linkage gear unit comprising gears with at least 6 teeth, where the gears are engaged with arc-racks, allowing for adjustable included angles and enhanced gear strength through increased contact ratio and reduced stress on individual teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If gears with few gear teeth are used in the folding joint mechanism, then the construction is simpler, but the contact ratio is lower and bearing stress is heavier, causing gear damage and reduced service life
Solution Approach 1:
The patent changes the key parameter of gear tooth count from few teeth to at least 6 teeth. This parameter change increases the contact ratio between mating gears, distributes bearing stress more evenly across multiple teeth, and prevents gear damage during folding and unfolding operations, thereby extending gear service life while maintaining construction simplicity
2Ease of manufacture
If a complete gear with included angle divisible by 360° is used, then the gear structure is standardized, but the design freedom and flexibility of the frame included angle are restricted
Solution Approach 1:
The patent transitions from a fixed, standardized gear configuration to a dynamic, adjustable system. By using a gear with at least 6 teeth that can be engaged with arc-racks at different positions, the frame included angle becomes adjustable rather than fixed, enabling the cart to adapt to different usage scenarios while maintaining manufacturability
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 extends the service life of the gear by distributing stress more evenly and provides greater design flexibility by allowing adjustable angles between the frames, enhancing the stability and usability of the cart.
Implementation Method 1
a linkage gear unit having a first gear and a second gear rotating coaxially, and the first gear being engaged with the first arc-rack, the second gear being engaged with the second arc-rack
Data Source
AI summary
A cart, at least a folding joint mechanism disposed among an upper frame, a bottom frame and a rear wheel frame, comprising a bottom frame joint having a first arc-rack, an upper frame joint having a second arc-rack, a rear wheel frame joint, and a linkage gear unit disposed between the upper and bottom frame joints, the linkage gear unit having a first and a second gears rotating coaxially and engaging with the first and second arc-rack respectively, and the first and second gears having the numbers N1 and N2 of gear teeth respectively, and wherein N1 and N2 are greater than or equal to 6.