Wheelchair Lift

Lightweight Lift for Sport Wheelchairs

Project Overview

This project was my assignment while working at Hinchey Design Co. My responsibility was to take the MK3 version of the lift and fix the major mechanical issues in the drive train while adding a safety release mechanism for the case of a battery failure when raised. I redesigned the front face of the lift so that it was clear to the user where each key function should be performed without looking.

Mechanism

The core mechanism I implemented on this product was a bi-directional one-way clutch. This mechanism allows the lift to raise and lower itself using the motor while transferring any back driving loads into the frame instead of the gearbox. This allows users to raise their chairs and do things while raised without draining battery holding motor position. It is the same mechanism that is in a cordless drill to allow it to rotate in either direction while not being back driven when you loosen the chuck. I also designed a lever cam-locking mechanism to allow users to lock and unlock the lift from the bottom of their chair using one hand between their legs

Prototyping

Nearly all of the design work for this project was done in SolidWorks, modeling many iterations and performing FEA to ensure they would hold up to loads. Some components, especially inside the new clutch I designed, needed to be physically prototyped to ensure they functioned correctly. The prototypes I made were 3D printed using off the shelf metal parts for the clutch's internal pieces. After the whole design was finalized, we got all of the parts machined to determine if they would work in a final solution. Below is a render I made of the wheelchair lift attaching to a chair, raising, then tucking away to drive off.