Wheelchair Backrest Pivot Mechanism for Whiplash Protection
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Solution Overview
Problem
Electrically powered wheelchairs occupants suffer neck injuries during vehicle collisions due to the lack of effective protection against acceleration-deceleration motions, which current securing methods fail to adequately address.
Innovation Solution
A seat arrangement for electrically powered wheelchairs featuring a backrest frame that pivots and tilts forward upon impact, with a retaining mechanism to maintain the backrest in an upright position until a threshold force is reached, then translates and locks into a forward-tilted position to catch the occupant's head, reducing whiplash injuries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wheelchair is secured in a vehicle by straps and the occupant is strapped with a safety belt, then the wheelchair movement is restricted, but the occupant still suffers neck injuries from acceleration-deceleration motion
Solution Approach 1:
The backrest frame is pre-configured in an upright position by the retaining mechanism during normal vehicle operation. In the event of a collision, the mechanism automatically transitions the backrest to a forward-tilted protective position before the occupant's head can rebound, thereby preventing whiplash injuries in advance
Solution Approach 2:
The invention converts the harmful forward-tilting force generated during a collision into a beneficial protective action. The collision force itself triggers the retaining mechanism to release and allows the backrest frame to pivot forward, catching the occupant's head and preventing injury from the same force that caused the potential harm
2Object-affected harmful factors
If the backrest frame is allowed to pivot freely to reduce injury risk, then protection is improved, but the backrest cannot maintain upright position during normal operation
Solution Approach 1:
The backrest frame transitions from a static upright position to a dynamic system that can automatically adjust between upright and forward-tilted positions. The retaining mechanism holds the backrest stable during normal operation, but automatically releases to allow forward pivoting when collision forces exceed the retention threshold
Solution Approach 2:
The system changes the positional parameter of the backrest frame based on collision conditions. During normal operation, the backrest maintains an upright position (0 degrees). Upon collision, the backrest pivots to a forward-tilted position (e.g., 15-30 degrees), changing its orientation parameter to provide optimal protection while maintaining comfort during normal use
3Stability of the object's composition
If a retaining mechanism is added to hold the backrest upright, then normal operation stability is improved, but the device complexity increases
Solution Approach 1:
The retaining mechanism is designed to automatically engage and disengage based on collision forces without requiring external control systems. The mechanism self-regulates by comparing the applied forward-tilting force against the retention threshold, releasing only when collision forces exceed the threshold, thereby maintaining simplicity while providing intelligent protection
Solution Approach 2:
The retaining mechanism acts as an intermediary element between the backrest frame and the collision force. It provides a controlled interface that allows the backrest to remain stable during normal operation while enabling automatic forward tilting when collision forces exceed the retention threshold, simplifying the overall system architecture
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 forward-tilting and locking mechanism significantly reduces the risk of whiplash injuries by minimizing the return motion of the occupant's head during collisions, providing enhanced protection for wheelchair occupants.
Implementation Method 1
the backrest frame is pivotally coupled to the seat frame, forming a first pivot axis, and wherein the backrest frame is pivotally coupled to the backrest actuator, forming a translatable second pivot axis
Implementation Method 2
the backrest frame is arranged to pivot about the first pivot axis and the second pivot axis to obtain a forward-tilted position
Implementation Method 3
a locking mechanism arranged to lock the backrest frame in the forward-tilted position
Implementation Method 4
a retaining mechanism arranged to retain the backrest frame in an upright position while the backrest frame is subjected to a forward-tilting force smaller than a threshold value
Data Source
AI summary
The present disclosure relates to a seat arrangement (1) for an electrically powered wheelchair, wherein the seat arrangement comprises (1): a mounting arrangement for mounting the seat arrangement (1) to a chassis of an electrically powered wheelchair, a seat frame (3), a backrest frame (5), a backrest actuator (7), wherein the backrest frame (5) is pivotally coupled to the seat frame (3), forming a first pivot axis (A1), and wherein the backrest frame (5) is pivotally coupled to the backrest actuator (7), forming a translatable second pivot axis (A2), a retaining mechanism (11) arranged to retain the backrest frame (5) in an upright position while the backrest frame (5) is subjected to a forward-tilting force smaller than a threshold value, wherein the retaining mechanism (11) is arranged to allow movement of the backrest frame (5) to a forward-tilted position when the backrest frame (5) is subjected to a forward-tilting force equal to or greater than the threshold value, and a locking mechanism (13) arranged to lock the backrest frame (5) in the forward-tilted position. An electrically powered wheelchair comprising a seat arrangement is also disclosed herein.