Pin Release Assembly for Wheelchair Latch Mechanism
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Solution Overview
Problem
Existing latch mechanisms for wheelchairs, particularly those with adjustable components like reclining seats, face issues with wear and increased costs due to the need for flexible connections that accommodate axial translation, which can lead to breakage.
Innovation Solution
A latch assembly with a rotational outer housing that drives axial movement of an inner spool and latch pin, utilizing a resilient member like a coil spring to ensure secure engagement and disengagement without requiring additional flexibility in the actuator connection, and incorporating sealing mechanisms to prevent contamination and retain lubricants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flexible connections (cable or jointed arrangement) are added to accommodate axial translation of the lock lever and actuator connection, then the latch mechanism can achieve the required axial movement, but the device becomes more complex and prone to wear, breakage, and increased costs
Solution Approach 1:
The patent combines the actuator connection and the axial movement accommodation into a single integrated structure. The actuator is directly connected to the lock lever without requiring separate flexible connections, as the lock lever's pivot connection to the stationary component inherently accommodates the axial translation. This merging eliminates the need for additional cables or jointed arrangements.
Solution Approach 2:
Instead of making the actuator connection flexible to accommodate axial movement, the patent inverts the approach by making the lock lever's pivot connection the accommodating element. The pivot connection, designed for rotational movement, is positioned and dimensioned to naturally accommodate the axial translation of the lock lever during operation, thereby eliminating the need for separate flexible connection elements.
2Adaptability or versatility
If flexible connections are used to accommodate axial translation, then the latch mechanism can operate, but reliability decreases due to wear and breakage risks
Solution Approach 1:
The patent combines the actuator connection and the axial movement accommodation into a single integrated structure. The actuator is directly connected to the lock lever without requiring separate flexible connections, as the lock lever's pivot connection to the stationary component inherently accommodates the axial translation. This merging eliminates the need for additional cables or jointed arrangements.
Solution Approach 2:
The patent extracts and eliminates the vulnerable flexible connection elements (cables or jointed arrangements) from the system. By redesigning the connection so that the lock lever's pivot connection directly accommodates axial movement, the patent removes the separate flexible connection components that were prone to wear and breakage, thereby improving reliability.
3Adaptability or versatility
If additional flexible connections are added to the latch mechanism, then axial movement is accommodated, but manufacturing cost increases
Solution Approach 1:
The patent combines the actuator connection and the axial movement accommodation into a single integrated structure. The actuator is directly connected to the lock lever without requiring separate flexible connections, as the lock lever's pivot connection to the stationary component inherently accommodates the axial translation. This merging eliminates the need for additional cables or jointed arrangements.
Solution Approach 2:
The patent extracts and eliminates the vulnerable flexible connection elements (cables or jointed arrangements) from the system. By redesigning the connection so that the lock lever's pivot connection directly accommodates axial movement, the patent removes the separate flexible connection components that were prone to wear and breakage, thereby improving reliability.
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 latch assembly provides reliable and durable securement of wheelchair components, reducing wear and cost by eliminating the need for flexible connections and ensuring effective sealing against contaminants.
Implementation Method 1
a resilient member, such as a coil spring, biased to move the latch pin into engagement
Implementation Method 2
an outer housing, subject to rotational movement, having a helical feature extending radially into an inner bore
Data Source
Figure 1A~1B
Figure 1C~2
Figure 3
AI summary
A pin release assembly comprises an outer housing that is held in place to allow the outer housing to only rotate. An inner spool is supported for axial movement in relation to the outer housing. Rotation of the outer housing axially moves the inner spool. The inner spool is operatively connected to a latch pin to selectively project and retract the latch pin.