Seat positioning system for a wheelchair
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Solution Overview
Problem
Existing seat positioning systems for wheelchairs lack flexibility and safety features, particularly in adjusting seat positions for optimal comfort and stability, especially during movements like tilting and vertical adjustments.
Innovation Solution
A seat positioning system that includes a seat frame coupled to a base frame via linkages and locking devices, allowing for forward-backward, tilting, and vertical movements, with solenoid-actuated plungers and catch mechanisms to control these motions, ensuring secure and adjustable seating configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a seat positioning system allows multiple degrees of freedom for adjustment, then flexibility and adaptability are improved, but stability and safety are compromised
Solution Approach 1:
The system employs dynamic locking mechanisms that can transition between locked and unlocked states, allowing the seat to be fixed in stable positions or adjusted to new configurations as needed. The solenoid-actuated plungers enable the system to dynamically switch between stable (locked) and movable (unlocked) states, resolving the contradiction between stability and adaptability.
Solution Approach 2:
The positioning system is divided into multiple independent adjustment mechanisms, each controlling a specific degree of freedom (forward-backward position, tilting angle, vertical height). Each mechanism has its own locking system, allowing individual segments to be adjusted or locked independently, thus maintaining overall stability while enabling comprehensive adaptability.
2Reliability
If locking mechanisms are added to control seat movements, then safety and stability are improved, but device complexity increases
Solution Approach 1:
The locking mechanisms are designed to be self-actuating through solenoid plungers that automatically engage or disengage based on electrical signals. The system provides self-service locking without requiring manual intervention for each locking action, reducing operational complexity while maintaining safety. The mechanical design of the plungers and catches creates inherent self-locking features that maintain reliability.
Solution Approach 2:
The solenoid-actuated plunger mechanisms serve multiple functions: they act as both actuators for movement and as locking mechanisms for stabilization. The same component that enables adjustment also provides the locking function, reducing the need for separate dedicated locking devices and thereby limiting the increase in system complexity.
3Measurement precision
If solenoid-actuated plungers are used for precise control, then positioning precision is improved, but device complexity and cost increase
Solution Approach 1:
The system replaces complex mechanical control systems with solenoid actuators that provide precise control through electrical signals. The solenoids offer controlled, repeatable positioning without the complexity of multiple mechanical linkages, cam mechanisms, or manual adjustment devices, thereby achieving precision while limiting the increase in overall system complexity.
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 system provides enhanced flexibility and safety by enabling precise control over seat positioning, maintaining stability during wheelchair movements and accommodating various user needs, while ensuring secure locking mechanisms for safety.
Implementation Method 1
The locking device includes a solenoid-actuated plunger
Data Source
AI summary
A seat positioning system includes a base frame having a pair of forward slots and a pair of rear slots, and a seat frame having a front end and a back end. The seat frame is coupled to the base frame and movable relative to the base frame. A first pair of linkages is slideably coupled to the pair of forward slots and connects the frames. A first pair of locking devices has a locked configuration adapted to prevent the first pair of linkages from sliding relative to the pair of forward slots and an unlocked configuration adapted to allow the first pair of linkages to slide relative to the pair of forward slots. A second pair of linkages slideably is coupled to the pair of rear slots and connects the frames. An actuator is pivotally connected to both the seat frame and the base frame and is configured to extend and contract to move the seat frame relative to the base frame.