Wheelchair Backrest Assembly With Sliding Pivot Linkage
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Solution Overview
Problem
Conventional wheelchair backrest adjustment assemblies are often bulky, obtrusive, and can cause discomfort due to pivot hinges contacting users, leading to uneven and potentially binding adjustments.
Innovation Solution
A compact backrest assembly with a support plate, slide plate, and actuator system that allows smooth pivoting between upright and reclined positions, eliminating the need for external pivot hinges and ensuring even adjustment without interference with armrests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pivot hinges are positioned at the lower portion of the backrest near the seat, then the backrest can be adjusted, but the pivot hinges contact the user's elbows causing discomfort and may bind up leading to uneven adjustment
Solution Approach 1:
The patent removes the traditional pivot hinges from the backrest structure entirely. Instead, the backrest is pivotally connected to the seat assembly through a connection mechanism positioned away from the user's body, extracting the harmful pivot hinges from the lower portion where they contacted user's elbows and caused discomfort.
Solution Approach 2:
The patent introduces a connection mechanism as an intermediary between the backrest and seat assembly. This intermediary connection structure allows the backrest to pivot without requiring exposed hinges near the user, mediating the rotational movement while keeping the pivot mechanism hidden and away from user contact areas.
2Ease of operation
If traditional backrest adjustment assemblies are used, then the backrest can be adjusted, but the assemblies are bulky and obtrusive
Solution Approach 1:
The patent merges the backrest support structure with the adjustment mechanism into an integrated assembly. The backrest, support plate, and connection mechanism form a unified structure that reduces the overall volume of the adjustment assembly compared to traditional separate components.
Solution Approach 2:
The patent repositions the adjustment mechanism in a different spatial dimension, connecting the backrest to the seat assembly through a pivotal connection that utilizes vertical and lateral space more efficiently, reducing the horizontal footprint and making the assembly less obtrusive.
3Ease of operation
If pivot hinges are positioned at the lower portion of the backrest, then adjustment is possible, but the hinges impede the user while trying to unseat themselves
Solution Approach 1:
The patent extracts the pivot hinges from the lower portion of the backrest where they interfered with user movement during unseating. The connection mechanism is repositioned to an location that does not contact or impede the user's arms or body during any movement, eliminating this harmful interference.
4Ease of operation
If pivot hinges are used in the backrest adjustment assembly, then the backrest can be adjusted, but the hinges may bind up leading to uneven and halting adjustment
Solution Approach 1:
The patent replaces the traditional mechanical pivot hinge system with an alternative connection mechanism that eliminates the binding problem. This substitution uses a pivotal connection designed to maintain smooth rotation without the friction and binding issues characteristic of conventional hinges, improving adjustment reliability.
Data Source
AI summary
A seat assembly including a seat, a support plate configured to pivot with respect to the seat, a slide plate slidably mounted to the support plate, and a pivot arm positioned between the support plate and the slide plate and connected to the slide plate and the seat. When the support plate is pivotally adjusted with respect to the seat, the pivot arm causes the slide plate to slide along the support plate.