Ergonomic ADA Stroller

As a senior-year design project, my team decided to develop a mechanism that would effectively connect a stroller to a wheelchair. This mechanism is optimized to simplify the task of driving a stroller for wheelchair-using parents.

Skills developed:

  • Product design

  • Market research

  • Ergonomics

  • ADA compliance

  • Mechanism selection

  • Rapid prototyping

  • Packaging

Software utilized:

  • SolidWorks (CAD)

  • Keyshot (Renders)

Tools put to use:

  • 3D-Printers

  • Lasercutter

  • Hand tools

Ideation & Mechanism Selection

We started with brainstorming potential solutions that would be able to tackle the problem at hand. After initial brainstorm, we narrowed down on two potential solutions and decided to make our mechanism a combination of these two ideas, with the concept of the mechanism featuring location, height, and angle adjustments (as demonstrated below).

We then developed the initial layout of the mechanism and created initial concept renders as part of the product pitch exercise.

Initial Layout

Scissor lift mechanism for adjusting the height of the baby carrier

Belt transmission mechanism for adjusting the facing angle of the baby carrier.

Planetary gear mechanism for adjusting the location of the baby carrier with respect to the wheelchair.

Prototyping

Rotation

We selected the rotation mechanism for adjusting the location of the wheelchair to based on the planetary gearbox system; this way the location of the baby carrier can be adjusted gradually and without requiring significant torque input, and the use of handles makes the mechanism easier to operate for most wheelchair-using parents.

Height Adjustment v.1

We initially selected the height of the baby stroller to be adjusted using a scissor lift mechanism due to its compact and stable geometry. However, during the prototyping stage, we determined that the rope used to operate the scissor lift would have to be in constant tension; if the rope were to ever fail, the baby stroller might fall to the ground which is likely to hurt the child. Therefore, we decided to pursue an alternative mechanism.

Height Adjustment v.2

As an alternative to the scissor lift mechanism, we decided to investigate a mechanism featuring a linear slider with a ratchet. This mechanism was designed to stay in the locked position until the pin was pulled out; once the pin was released, it would immediately lock in the existing position, preventing the carriage with the child from falling. To help the parent lift the carriage up, we intended to use constant force springs that would compensate for the weight of the carriage, leaving the parent lifting just the weight of their child.

Attachment to Wheelchair

Because wheelchairs tend to vary in designs, we decided to make the attachment of the mechanism versatile in order to accommodate most wheelchairs on the market. In this attachment mechanism, we combined the V-blocks used for holding circular stock in vice grips and C-clamps used for clamping onto flat surfaces; this allows the mechanisms to clamp onto tubing of various outer diameters present in most wheelchair designs on the market.

Full Structure

At the moment, we are developing the final prototype of the mechanism that integrates all systems together; we are doing so in order to check the functionality, ergonomics, and ease of use of the mechanism. Stay tuned!

SolidWorks design of the final prototype.

Full prototype made using 3D-printing and lasercutting.