An Escalator Compatibility Kit for Wheelchairs Ladies and Gentlemen: Presenting, the senior mechanical engineering design project at the Illinois Institute of Technology – This is a Red Team/Boost Group Presentation - An Escalator Compatibility Kit for Wheelchairs.
Having brainstormed a hundred different ideas at the beginning of the semester, our team of senior Mechanical Engineering students narrowed down the best ideas and selected this idea –an after-market kit for a wheelchair to make it compatible on an escalator - its the ESC System.
Design Objective The objective of this system is for the user of a wheelchair to safely ascend and descend an escalator with ease and with maximum safety.
Design Requirements The design of the system is required to be light weight, robust and must support a person of 250 pounds weight. Details: The system must be able to support either the front end, back end or both ends of the
wheelchair and support the person sitting on it throughout the ride on a standard width escalator.
Design Ideas Initial ideas for the system included a double-lever-arm that will give the user a mechanical advantage by reducing the force required to lift up wheelchair on an escalator. Further refinement of the idea gave the possibility of including gears and a telescopic support rod. A more complex idea is to incorporate pneumatic suspension for the system that helps to raise the front end of the wheelchair during travel on the escalator. A simple mechanical support rod system was the idea the team decided to use for the building of the mock up model and alpha prototype in the design stages for this product.
Design Process Based on the Design Objective and Design Requirements, the team followed the following design process. Data Collection: the team collected some test data for the wheelchair weight distribution. Using weighing machines, the forces on each of the four wheels was measured and was found that the front wheels support a total 30% of the weight. Brainstorming: To come up with various solutions, the team brainstormed as a group to create multiple solutions, each with a certain degree of complexity.
Analysis of Ideas Using the FRSARRC chart method of evaluating each idea, the team chose a single design that is easy to manufacture, has a high level of safety and with a user-friendly work mechanism.
The idea of using a set of telescopic extending rods that support the front of the wheelchair during its ride on the escalator was chosen. This enables the wheelchair user to travel up or down the escalator staying parallel to the surface of the wheelchair. On the way up, the wheelchair riders needs to ride backwards onto the escalator. On the way down, the wheelchair rider can go forward facing with ease.
Our analysis was done using the principles of mechanical stresses on solids. The stresses on the rods, brackets, the screws holding the brackets and the system, and the clamps holding the system were calculated. The details of the analysis are here
Engineering Drawings A few of the ideas were translated into CAD drawings using the software Pro-Engineer.
ProE assembly of primary design
ProE rendering of ESC System
ProE rendering of System
System photographs Shown below are the photos of the team-built mock-up model and the final product.
Mock-up Model Design
Alpha-prototype Model Close-up
Manufacture Process The product was entirely fabricated at the MMAE Department at IIT with the help of Machine Shop in the basement. The team also worked in the IIT SAE Garage with the help of MMAE student John Mccluskey. The team is thankful to the machine shop expert Craig Johnson and also our peer John Mccluskey for helping us machine the parts. Details of the manufacturing process are detailed here.
Future Improvements After testing, there were some things that were found that could be improved in order to enhance the performance and the appeal of the product. Some of the changes are more for aesthetics while others are to enhance product:
Videos Some of the testing was captured on a video.
You can find these videos here and here too. Notice-the video has music!
Team Meet the team.
Having brainstormed a hundred different ideas at the beginning of the semester, our team of senior Mechanical Engineering students narrowed down the best ideas and selected this idea –an after-market kit for a wheelchair to make it compatible on an escalator - its the ESC System.
Design Objective The objective of this system is for the user of a wheelchair to safely ascend and descend an escalator with ease and with maximum safety.
Design Requirements The design of the system is required to be light weight, robust and must support a person of 250 pounds weight. Details: The system must be able to support either the front end, back end or both ends of the
wheelchair and support the person sitting on it throughout the ride on a standard width escalator.
Design Ideas Initial ideas for the system included a double-lever-arm that will give the user a mechanical advantage by reducing the force required to lift up wheelchair on an escalator. Further refinement of the idea gave the possibility of including gears and a telescopic support rod. A more complex idea is to incorporate pneumatic suspension for the system that helps to raise the front end of the wheelchair during travel on the escalator. A simple mechanical support rod system was the idea the team decided to use for the building of the mock up model and alpha prototype in the design stages for this product.
Design Process Based on the Design Objective and Design Requirements, the team followed the following design process. Data Collection: the team collected some test data for the wheelchair weight distribution. Using weighing machines, the forces on each of the four wheels was measured and was found that the front wheels support a total 30% of the weight. Brainstorming: To come up with various solutions, the team brainstormed as a group to create multiple solutions, each with a certain degree of complexity.
Analysis of Ideas Using the FRSARRC chart method of evaluating each idea, the team chose a single design that is easy to manufacture, has a high level of safety and with a user-friendly work mechanism.
The idea of using a set of telescopic extending rods that support the front of the wheelchair during its ride on the escalator was chosen. This enables the wheelchair user to travel up or down the escalator staying parallel to the surface of the wheelchair. On the way up, the wheelchair riders needs to ride backwards onto the escalator. On the way down, the wheelchair rider can go forward facing with ease.
Our analysis was done using the principles of mechanical stresses on solids. The stresses on the rods, brackets, the screws holding the brackets and the system, and the clamps holding the system were calculated. The details of the analysis are here
Engineering Drawings A few of the ideas were translated into CAD drawings using the software Pro-Engineer.
ProE assembly of primary design
ProE rendering of ESC System
ProE rendering of System
System photographs Shown below are the photos of the team-built mock-up model and the final product.
Mock-up Model Design
Alpha-prototype Model Close-up
Manufacture Process The product was entirely fabricated at the MMAE Department at IIT with the help of Machine Shop in the basement. The team also worked in the IIT SAE Garage with the help of MMAE student John Mccluskey. The team is thankful to the machine shop expert Craig Johnson and also our peer John Mccluskey for helping us machine the parts. Details of the manufacturing process are detailed here.
Future Improvements After testing, there were some things that were found that could be improved in order to enhance the performance and the appeal of the product. Some of the changes are more for aesthetics while others are to enhance product:
- A mirror could be attached to the wheelchair to offer a better view as the user is backing into the escalator.
- Another telescoping feature could be added to the support rods in order to lower the bars out of users way.
- The material used for the locking pins to increase friction or deeper groves in the aluminum block for the pins to fit in would allow for the locking pins to stay in place when riding over rough surfaces.
- The size of the aluminum blocks could be decreased in order to lessen the weight of the product.
- The pipe straps would be custom made to fit securely around the wheelchair.
Videos Some of the testing was captured on a video.
You can find these videos here and here too. Notice-the video has music!
Team Meet the team.