Wheelchair Crossing Mechanism With Spring-Loaded Wheel Alignment
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Solution Overview
Problem
Existing obstacle-crossing devices for motorized vehicles, such as wheelchairs, face challenges in adapting to uneven ground and maintaining stability when crossing obstacles, particularly curbs, due to fixed wheel alignment and lack of effective contact and support between wheels.
Innovation Solution
The device incorporates a mechanism with three wheels on each side, where the front and rear wheels can pivot independently, using a slide and spring system to adjust wheel alignment and contact with the ground, and includes anti-tilt casters for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the wheelchair uses fixed wheel alignment, then the structure is simple and stable, but it cannot adapt to uneven ground and obstacles effectively
Solution Approach 1:
The patent implements dynamic wheel alignment by allowing the rear wheel to pivot independently relative to the longitudinal member through a slide mechanism. This enables the wheel configuration to adapt continuously to uneven terrain and obstacles, transforming the static wheel arrangement into a dynamic system that self-adjusts to ground conditions.
Solution Approach 2:
The patent divides the wheel alignment system into independent segments - the front wheel assembly and the rear wheel assembly can move independently relative to each other and to the ground. This segmentation allows each wheel to negotiate obstacles independently, improving overall adaptability without requiring complex centralized control.
2Stability of the object's composition
If the wheelchair lacks effective contact and support between wheels, then the structure is simpler, but stability when crossing obstacles is reduced
Solution Approach 1:
The spring means automatically adjusts the rear wheel position to maintain optimal contact with the ground during obstacle crossing. The system self-regulates through the spring force, which pushes the rear wheel into engagement with the ground when needed, eliminating the need for complex active control mechanisms while ensuring stable wheel contact.
Solution Approach 2:
The spring mechanism provides mechanical feedback by automatically adjusting rear wheel contact based on ground conditions. When the rear wheel loses contact during obstacle negotiation, the spring force restores contact, creating a self-correcting system that maintains stability without external intervention.
3Ease of operation
If the rear wheel remains in fixed alignment, then the mechanism is simpler, but it cannot optimize contact with ground during obstacle crossing
Solution Approach 1:
The rear wheel assembly is designed to pivot dynamically relative to the longitudinal member through the slide mechanism, allowing the wheel to automatically optimize its contact angle with the ground during obstacle crossing. This dynamic adjustment occurs passively through the mechanical design rather than requiring active control.
Solution Approach 2:
The patent changes the positional parameter of the rear wheel relative to the longitudinal member during obstacle crossing. The slide mechanism allows the rear wheel to move along the longitudinal member, changing its contact parameters with the ground to optimize traction and stability during different phases of obstacle negotiation.
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
Enables stable crossing of obstacles up to 20 cm high without tipping, improving maneuverability and adaptability to uneven terrain, ensuring optimal wheel contact and support during obstacle negotiation.
Implementation Method 1
At least one spring means (18) is interposed between said two walls
Implementation Method 2
at least one spring means being interposed between said two walls, while the arm is dimensioned so that its free end comes into contact with the wall so as to push back the slide while constraining the spring means against said wall
Data Source
AI summary
The obstacle-crossing device for a motorized vehicle having a chassis connected to three wheels on each lateral side of the chassis and a motor to rotate the wheels. There is a mechanism having two arms articulated in pairs about a common pivot axis. The device includes an arm articulated to the chassis on a longitudinal member via a pivot connection. The end of the arm that extends beyond the pivot connection and opposite the motor cooperates with a slide movable on the longitudinal member. A front wheel has a first position in alignment with the other two wheels and a second position which is lowered with respect to the alignment of the other two wheels. The longitudinal member has a fixed wall, and at least one spring. The arm is dimensioned to push back the slide while constraining the spring when the front wheel is in its first position.