Generate a minimum of 2 concepts for creating a detachable/addable mechanism intended for existing manual wheelchairs, aimed at preventing musculoskeletal disorders in the upper body of manual wheelchair users by reducing repetitive, unnatural propulsion movements.

 

*note: we're not redesigning an entire wheelchair (because it would be too expensive to do so and can create complications when things don't go right -- essentially a device that wheelchair users can purchase and add to their wheelchair easily that will reduce long-term shoulder pain and don't have to manually propel themselves

 

Consider some of following design parameters for this mechanism when coming up with concepts:

• Adjustable to accommodate users ranging from the 5th percentile female reach to the 95th percentile male reach.
• Aligned with the natural range of shoulder and arm motion (maximum 30° shoulder extension and maximum 70° shoulder flexion).
• Ensures that the force required for propulsion remains at or below 40 Newtons.
• Comprises fewer than 15 total components or parts.
• Weighs approximately 5-10 pounds.
• Incurs a production cost of less than $100.
• We're thinking of doing a gear/level type of mechanism with a brake and reverse shifts with an ergonomic grip, etc. (what would be an ideal design to incorporate that? like similar to a bike handle, etc?

**Since this is an engineering brainstorming concept approach,  you should be sketching ideas along with equations, free body diagrams, information flow diagrams, sketches of what the wheelchair mechanism would look like and how it would attach to the wheelchair, material properties, etc. -anything relevant to the project.