Mobility Vehicle Suspension With Angled Spring Axes for Stable Seating
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Solution Overview
Problem
Existing mobility vehicles face challenges in providing a stable and smooth ride over uneven terrain while maintaining a horizontal seating orientation for users, particularly in wheelchairs, due to inadequate suspension systems and pivot arm configurations.
Innovation Solution
A mobility vehicle with a suspension assembly featuring angled spring axes and pivot arms that include anti-tip elements, stiffening rods, and differential spring responses to enhance stability and ride comfort, coupled with independently pivotable caster wheels and drive wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a suspension assembly with angled spring axes is used, then ride comfort and stability are improved, but device complexity increases
Solution Approach 1:
The suspension assembly is segmented into multiple independent spring assemblies (first spring assembly with first spring axis, second spring assembly with second spring axis) that can be independently configured. Each spring assembly handles specific suspension tasks, allowing the system to achieve complex suspension behavior through simpler individual components working in coordination.
Solution Approach 2:
The patent introduces angular orientation as a new dimension for spring configuration. By positioning spring axes at different angles relative to each other and to the pivot arms, the system achieves enhanced stability and ride comfort without adding more spring assemblies, effectively using spatial arrangement to solve the contradiction.
2Reliability
If pivot arms are configured to allow wheel movement over uneven terrain, then ride comfort is improved, but maintaining horizontal seating orientation becomes difficult
Solution Approach 1:
The suspension assembly acts as a counterbalancing mechanism that compensates for terrain irregularities. The spring assemblies provide restoring forces that counteract the tilting moments generated when wheels move over uneven ground, thereby maintaining the seat in a relatively horizontal orientation while still allowing wheel movement for ride comfort.
Solution Approach 2:
The pivot arms are designed to be dynamically adjustable, allowing the system to adapt its configuration based on terrain conditions. The ability of the pivot arms to rotate and the spring assemblies to compress and extend enables the system to dynamically maintain seating orientation while accommodating wheel movement over various terrains.
3Reliability
If anti-tip elements are added to pivot arms, then vehicle stability is improved, but device complexity increases
Solution Approach 1:
The anti-tip elements are merged with the existing pivot arm structure rather than being separate add-on components. The pivot arms are configured and dimensioned to cause the anti-tip elements to move relative to the drive wheel axis when the pivot arms rotate, integrating the anti-tip function into the normal pivot arm operation and minimizing additional complexity.
4Strength
If stiffening rods are used to rigidize the frame, then structural strength is improved, but adaptability to terrain decreases
Solution Approach 1:
The frame is segmented into rigid sections connected by flexible pivot joints. The stiffening rods reinforce specific frame sections to provide structural strength where needed, while the pivot arms and suspension assemblies at the connections maintain flexibility and adaptability to terrain variations, allowing the frame to behave as a combination of rigid and flexible elements.
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 solution provides enhanced stability and a smoother ride by adjusting to uneven terrain, maintaining a horizontal seating position, and minimizing the vehicle's footprint, while ensuring consistent damping rates throughout wheel movement.
Implementation Method 1
The suspension assembly may include a first spring assembly, disposed about a first spring axis, and coupled to the first pivot arm; and a second spring assembly, disposed about a second spring axis, and coupled to the second pivot arm
Implementation Method 2
At least one of the first spring assembly and the second spring assembly may include a spring disposed about co-axial damper
Data Source
AI summary
A mobility vehicle may comprise a frame, a first pivot arm, a second pivot arm, and a suspension assembly. The first pivot arm may be coupled to the frame and coupled to a drive wheel. The second pivot arm may be coupled to the frame and coupled to a ground engaging caster wheel. The suspension assembly may be coupled to the frame. The suspension assembly may include a first spring assembly and a second spring assembly. The first spring assembly may be disposed about a first spring axis and coupled to the first pivot arm. The second spring assembly may be disposed about a second spring axis and coupled to the second pivot arm. The first spring axis and the second spring axis may be disposed relative to each other at an angle of no greater than about 150° when the mobility vehicle is operating on horizontal ground.