Folding Cart Leg Mechanism with Trigger Lock
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Solution Overview
Problem
Conventional folding carts with pivoted rear legs do not optimize the folding mechanism for compactness and stability, leading to suboptimal space savings and user experience during folding and unfolding operations.
Innovation Solution
A folding cart design featuring a rectangular frame with specific hole configurations and a folding device comprising a trigger, pivots, and a torsion spring mechanism that allows for secure locking and unlocking of the legs, enabling efficient folding and unfolding by utilizing a pin with an enlarged head and annular groove, along with a biasing member and clip ring for enhanced stability and ease of use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional pivoted rear legs are used, then the cart structure is simple, but the folding mechanism does not optimize compactness and space savings
Solution Approach 1:
The leg structure is divided into multiple segments (upper leg portion, lower leg portion) that can pivot relative to each other. The trigger mechanism is also segmented with separate components (trigger body, projection, biasing member) that work together to control the folding action, allowing compact folding while maintaining structural integrity
Solution Approach 2:
The leg structure transitions from a static rigid structure to a dynamic folding structure with movable joints. The biasing member provides dynamic force to automatically return the leg to its extended position after folding, making the folding mechanism both compact and functional
2Reliability
If the leg folding mechanism is simplified, then the device complexity is reduced, but the stability and locking reliability during folding/unfolding deteriorates
Solution Approach 1:
The biasing member automatically provides the force needed to return the leg to its extended and locked position after folding, without requiring manual intervention. The trigger mechanism self-latches into position, providing reliable locking through the inherent mechanical design rather than requiring additional complex locking components
Solution Approach 2:
The projection on the trigger acts as an intermediary element that engages with the leg structure to control and secure the folding motion. This intermediate component transfers and controls the forces between the trigger and the leg, ensuring reliable locking while maintaining a relatively simple overall structure
3Ease of operation
If a secure locking mechanism is implemented, then the stability is improved, but the ease of operation during folding and unfolding deteriorates
Solution Approach 1:
The biasing member automatically provides the return force that pushes the trigger back to its original position after folding, making the unfolding operation simple and requiring minimal user effort. The mechanism serves itself by storing and releasing mechanical energy to assist the folding/unfolding cycle
Solution Approach 2:
The trigger mechanism extracts and isolates the locking function from the main leg structure. By separating the locking action into a distinct trigger component with its own biasing member, the design achieves both secure locking and easy operation - the user simply presses the trigger to release the lock, and the biasing member handles the return motion
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 solution provides improved folding and unfolding efficiency, ensuring the cart can be compactly stored while maintaining stability, enhancing user convenience and space-saving capabilities.
Implementation Method 1
a biasing member put on the pin and disposed in the first hole member, the biasing member having one end urging against the shoulder
Implementation Method 2
a first pivot driven through the first pivot hole, the second pivot hole, and the fastening hole to pivotably fasten the upper portion of the leg between the corner plate and the inner extension
Data Source
AI summary
A folding cart includes a frame including front and rear plates having two inner extensions with a fastening hole, and four corner plates having a first pivot hole, a first hole, and an oval second hole; two rear wheels; four legs having a second pivot hole, a first hole member, and a second hole member; and four folding devices each including a trigger including two bent wings having a first through hole, and a top projection having a second through hole; a first pivot driven through the first pivot hole, the second pivot hole, and the fastening hole; a second pivot driven through the second hole member and the first through holes; a spring loaded pin driven through the first hole member and the second through hole; and a clip ring partially disposed in the groove and urging against the projection.