Amanda Gelb (NYU), Debra Cohen (NYU), Stefan Henry (CUNY), Charles Shim (CUNY), Christian Pither Salvatierra (CUNY), Christopher Philip Tinevra (CUNY), Roberto Carlos Oporto (CUNY)
ABSTRACT:
Wheels Up is a low-cost mechanism enabling those in wheelchairs to autonomously climb any combination of steps approx. 2’’ to 24’’ in height. Specifically, it will enable power chair users to ascend one step and manual wheelchair users with upper body mobility to ascend a few steps. This tool was designed hand-in-hand with the input of a hundred wheelchair users via a survey we conducted (appendix A). It utilizes new applications of material and mechanism by using geometric folding algorithms, hydraulics, 3D printing and modular furniture design. We hope this tool can ultimately be used for aging in place, walkers, and strollers.
THE PROBLEM:
Restaurants. Bars. Curbs without a curb cut. Pesky elevator apartment buildings with 3 shallow stairs before the entrance. Dr. offices. Barber shops. Nail salons.
Ramps are missing from many built environments where a small set of steps act as a monolithic insurmountable barrier to entry for countless people in manual and power-based wheelchairs.
We sought to answer the question: How can persons who use wheelchairs go up a few stairs autonomously?
SUPPORTING RESEARCH:
With the popularity of elevators and the ADA’s tremendous progress in mandating ramps be placed in new and renovated buildings, significant progress has been made in making our urban and residential environments more accessible. And yet, countless clients in cities ranging from New York to North Carolina to Alaska reported the same difficulty with small sets of steps (appendix A).
One third of users of wheeled mobility devices report they have accessibility difficulty getting around outside their houses (1).
Further, there is a significant lack of ramps in the elderly population:
Roughly 10% of community-dwelling older Americans live in a residence with a ramp at the entryway, which reduces the odds of outdoor mobility difficulty threefold among those using wheeled mobility devices (2).
This leaves a gaping 90% of older Americans that lack ramps to their residences. Restaurants also provide an opportunity for increased access:
Two thirds of the 120 restaurants surveyed required a ramp to enter. However only 66% provided one (3).
Even curb cuts limit mobility for wheelchair users in residential or urban environments:
To determine the standard to which curb ramps in an urban area met a set of wheelchair accessibility guidelines. 79 intersections were assessed. In Canada only 43.6% of the curb ramp had the correct slope measurement. Only 26.9% of the curb ramp had a smooth transitions. And 53.8% had direct line of travel. (4)
SOLUTION STATEMENT:
A device that will grant wheelchairs untold access to hundreds of establishments and city streets previously inaccessible. Primarily, a solution to the lack of access to many institutions, businesses, and streets throughout the cities described in our study.
After initial quantitative research (appendix A) and qualitative user interviews the following main foci for this solution presented as: portability, quick and easy use, durability, inexpensive cost, and easy adherence to the chair with minimal footprint. A design that is delightful and encourages use was top of mind throughout the design process.
Further, while this assistive technology is currently aimed at those in wheelchairs, its designers incorporated principles of universal design so it can ultimately be applicable for scooters, strollers, walkers, and aging in place home modification.
METHODS:
This was a quest for both mechanism and material over a the duration of fourteen weeks, with the hope of creating and socializing many prototypes before narrowing to two with the input of many stakeholders.
1) INCORPORATING USER FEEDBACK:
It was essential to our team that we engage in participatory design practices to design with and not on behalf of wheelchair users. To ensure that this device was informed by wheelchair users we conducted a study of 100+ wheelchair users across the globe. We drew from these findings, Appendix 1, at every stage in the design process.
In addition to the aforementioned wheelchair users we spoke with family members, caregivers, occupational therapists, physical therapists, and day care facility managers to gauge their comfort and potential use of our solutions. These stakeholders also provided significant feedback on our models.
We also conducted in-person problem and visioning interviews, design feedback,and lastly, user tests, at NYC United Cerebral Palsy, Wheeling Forward, and The Axis Project so that the features we designed were vetted by a large group of future users. Lastly, our own team member, Stefan Henry, who lent critical mechanical engineering advice, is also a power chair user.
2) USER FEEDBACK AND SURVEY MAIN FINDINGS:
NYC itself bans any ramps that are not to the ADA code of 1 inch of rise by 12 inches of run, a near impossible task given the width of many urban storefront and residential housing steps. In order to be used the design would need to be incredibly simple to use and deploy easily. Further, it would need to take up minimal precious real estate on the chair itself or in the user’s backpack. Wheelchair users don’t want heavy things on their chairs so achieving a lightweight design is tantamount to its adoption. While we aim for this device to be multi-purpose and of use for different step height scenarios, it entails the user knowing which height to deploy.
3) MECHANISM:
First we undertook a study of research and trial and error experimentation of various known mechanisms, folding techniques, and materials. We began by building model stair scenarios to scale, in addition to a proportional wheelchair. We used paper and other low cost items to crank out a high amount of scenarios.
This design was ultimately eliminated due to family members and attendants fears of raising their loved ones up off the ground.
Mechanisms we researched included ball and sockets, pistons, gears, sprockets, chains, levers, pulleys, ratchets, hooks and lifting magnets, vacuum cups, conveyors, latches and catches, bolts and pins, tracks, and hoists. Folding techniques consisted of: rigid origami and pop up books.
We initially thought to build a ratcheting system that would fasten to the hub of the wheel and be deployed by the client via a lever at arm level. The client would navigate the stairs going backwards, which is more comfortable according to many users interviewed. A rubber covered kickstand would act as a third point of contact to increase safety.
This design was shelved for another time due to the occupational therapists concerns that center of gravity might pivot, the breakers we were proposing to use weren’t strong enough to prevent the chair from slipping, and there was additionally nothing to prevent the client from bumping their heads on the steps above them.
Modular furniture and designing by way of modular units was also examined.
We met with furniture designer Ian Stell who was intrigued by our project and shared some of his interlocking techniques.
4) MATERIAL:
Materials explored included: thermal materials, linear actuators, carbon fiber, new lightweight alloys and complex composites, maple and other durable wood and veneers, and plastics used in 3D printing.
As part of research into material our teammate took a trip to the Material ConneXion’s Materials Library, to gain inspiration and note materials for future builds and when further funding is secured.
NARROWED SET OF SOLUTIONS AND FINAL RESULTS:
We ultimately landed on sliding ramps that are 6’’ wide and extend to a total of 60’’. 6’’ was the average comfortable width that minimized material and maximized diameter from outer caster to inner wheel of five diverse wheelchairs we measured. Three panels of 20’’ length enable a length that when collapsed fits the average dimensions of a chair’s seat back. The ramps are connected in the middle with a telescoping pole to enable width adjustments for diverse wheelchairs and minimal space usage. Lengths can be locked into place with a spring-loaded pin that fits into fabricated holes in the sides of the device.
Version Above with Steel and Aluminum
Sandpaper was added for increased friction and playful design.
Rubber grips hug the top landing of the steps while a rubber-bottomed hinge creates grip. These features enable the ramp to not be held incumbent to the natural rise and run of the step height and tread below it, as there was little standardization in the countless 1-4 steps we measured.
We further began to explore complex composites used in aerospace and nautical design and landed on an aluminum honeycomb composite that weighs 1lb for a 12’’ x 12’’ panel.
Of our initial research and conversations regarding materials we began to explore 3D printing as a form of wedges that would be lightweight and support 500+ lbs. Below is a series of models that use minimal filament and provide maximum support. We selected ABS filament due to its non-brittle and highly durable nature.
We then ran stress tests on these models in the program Solidworks, to test their shear, tensile strength, and maximum load they can bear.
While these ramps are lightweight and support our desired load, our solution was only half finished. We still required a deployment and retrieval system for our quadriplegic clients, given that this solution is primarily aimed at powerchair users. To that end we created some robotic arms that would be retrofitted to a power chair.
These arms hold the wedges and lower and release them at the click of a button. Our shop was unanticipatedly closed for the past 3 weeks so our build of these arms has slowed but consider this series of images and the linked video which illustrates our initial concept with our wood and mat board prototype in action.
A scissor-like mechanism extends and contracts the bars further, enabling the wedge to anchor to the ground.
COST/IMPLICATIONS:
Total cost for each 3D wedge, depending on the design, ranged from $500-700, too high for our users. We fashioned wedges out of plywood for prototyping our extending arms for now. In the future if these go to production we can injection mold the wedges for less cost.
The robotic arms are comprised of thin steel rods, clamps and small pistons, valuing a total of $300 for two.
The portable extendable ramps for manual wheelchairs cost $130 for the honeycomb aluminum panel and $50 for the U channels, totaling $200 when considering the weld. The rubber we used at the ends we re-purposed from slashed mountain bike tires from a bike store’s trash bin near campus.
All costs were drawn from client’s confidential suggestions (appendix a, question 17).
Acknowledgments, References:
1. LaPlante, M., & Kaye, H. (2010). Demographics and trends in wheeled mobility equipment use and accessibility in the community. Assistive Technology, 22(1), 3-17. doi:
2. Clarke, P. (2014). The role of the built environment and assistive devices for outdoor mobility in later life. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences, 69. doi:
3. McClain, L., Beringer, D., Kuhnert, H., Priest, J., Wilkes, E., Wilkinson, S., & Wyrick, L. (1993). Restaurant Wheelchair Accessibility. The American Journal of Occupational Therapy, 5(2).
4. Bennett, S., Kirby, R., & Macdonald, B. (2009). Wheelchair accessibility: descriptive survey of curb ramps in an urban area. Journal of Disability and Rehabilitation, 4(1), 17-23.
Appendix A: https://drive.google.com/file/d/0B3C4WcGAEpuhdkVwenItOUNpLVk/view?usp=sharing
Many thanks to NYU’s ITP program, the Ability Lab for their generous grant, the NYU Prototyping Fund for supporting our proposal and the multitude of professors and wheelchair users who weighed in on our survey and in-person interviews.