Wheelchair Wheel Backstop and Gear-Shift Arrangement
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Solution Overview
Problem
Existing wheelchair wheel systems lack a user-friendly and efficient mechanism for simultaneously engaging a backstop function and shifting gears, leading to increased energy consumption and wear when the backstop is engaged during continuous motion.
Innovation Solution
A combined backstop and gear-shift arrangement that allows the engagement of a backstop function using the same rotational movement as gear shifting, utilizing a backstop selector connected to a gear-shift mechanism within an internal-gear hub, enabling the user to engage or disengage the backstop function seamlessly with familiar gear-shifting motions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the backstop mechanism is permanently or automatically engaged, then the wheelchair wheel can prevent backward rolling, but the energy consumption increases and the mechanism suffers from increased wear during continuous forward motion
Solution Approach 1:
The backstop mechanism is designed to be dynamically engageable and disengageable through a selector valve that can be operated by the user. The mechanism transitions from a static permanently-engaged state to a dynamic state where engagement can be adjusted based on actual need, allowing the backstop to be engaged only when preventing backward rolling is required and disengaged during continuous forward motion to minimize energy consumption and wear.
2Reliability
If the backstop mechanism is permanently or automatically engaged, then the wheelchair wheel can prevent backward rolling, but the mechanical wear increases
Solution Approach 1:
The backstop mechanism is designed to be dynamically engageable and disengageable through a selector valve that can be operated by the user. The mechanism transitions from a static permanently-engaged state to a dynamic state where engagement can be adjusted based on actual need, allowing the backstop to be engaged only when preventing backward rolling is required and disengaged during continuous forward motion to minimize energy consumption and wear.
3Adaptability or versatility
If separate levers are used for gear shifting and backstop operation, then both functions can be independently controlled, but the device complexity and ease of operation decrease
Solution Approach 1:
The patent combines the gear shifting mechanism and the backstop selector into a single integrated selector valve. This allows the user to perform both gear shifting and backstop engagement/disengagement through one unified control interface, reducing the number of separate levers or controls needed. The combined mechanism maintains the ability to independently control both functions while significantly improving ease of operation by eliminating the need to manage multiple separate controls.
Data Source
Figure 1
Figure 2a~2c
Figure 2d~2f
AI summary
A wheel assembly comprising a wheelchair wheel (5) and a backstop arrangement (10; 30; 70) configured to selectively engage and disengage a backstop function and comprising a backstop selector (15; 35; 75) and a backstop member (18; 38; 78), wherein the wheel (5) comprises an internal-gear wheel hub (11; 31; 71) comprising a number of internal gears (57, 58) and having an inner rotatable circumferential surface (13; 33; 73), and wherein the backstop member is configured to allow the inner circumferential surface to rotate in one direction and to prevent rotation in the opposite direction. The wheel assembly comprises further a gear-shift arrangement comprising a shift member (54), which is axially moveable within the internal-gear hub (31) to engage a specific gear of said number of internal gears (57, 58), and wherein the shift member (54) via a connector member (55) is operatively connected to the backstop selector.