Designers: Akshay Buddiga, Aman Mittal, and Ankit Rajgariah
Client Coordinators: Victoria Guthrie, PT, and Catherine Alguire, OTR
Supervising Professors: Kevin Caves and Richard Goldberg
INTRODUCTION
Emma is a bubbly six year-old girl with spina bifida, a congenital deformation in which the vertebral arch of the spine forms improperly. This leads to a loss of sensation in the body below the deformation, so Emma uses a manual wheelchair at school and at home. In school, Emma moves independently in the classroom and hallways with her wheelchair. However, Emma cannot operate her wheelchair and carry her belongings at the same time. She needs the assistance of a teacher to carry her notebooks, pencils, and a water bottle in the classroom and a lunch tray in the cafeteria. The client would like to be able to do these tasks independently. Commercial solutions do exist, such as removable lap trays, flip away lap trays, water bottle holders, and small detachable carry pouches. However, these products do not fit Emma’s Zippie Zone wheelchair.
We developed a set of assistive devices that attach to Emma’s wheelchair and help her carry her belongings independently. Three devices were developed: a removable lap tray stored on the side of the wheelchair, a water bottle holder, and a bag to carry miscellaneous items. With the devices attached to her wheelchair, Emma can still push her wheels, get in and out of the chair, and move through doorways. All of these devices are easily removable when necessary.
STATEMENT OF IMPACT
Before this device was constructed, Emma was unable to transport various objects independently while at school. Her therapist described the tray as being able to hold “mainly her lunch and…her books” and will help prevent Emma from “dropping things.” The water bottle holder and bag will be very helpful because sometimes she “can’t reach” her water and other miscellaneous items and must “ask someone.” Emma exclaimed when describing the devices that she “can reach them now!” Finally her therapist stated, “Next year [she] will be in second grade and will be able to do all of these things for [herself]. That’s so awesome.”
Figure 1. (a) Shows the lap tray in the storage position on the right side of the wheelchair. This position still provides her access to the wheels so that she can propel her wheelchair. To use the lap tray, the client can slide the tray forward and swing it across the chair, putting it in the position shown in (b). The storage bag is located under the left armrest
DESIGN AND DEVELOPMENT
The lap tray enables Emma to carry a variety of things, including a lunch tray in the cafeteria. It also serves as a writing/reading surface when a desk or table is not readily available. Unique aspect of the tray’s design are that Emma can easily convert between a storage and a usage position by herself, and that the tray remains attached to the wheelchair at all times. In storage, the tray is hung to the right side of the wheelchair on 4” carriage bolts that have been drilled into an aluminum bar, as shown in figure 1a. The bolts hold the tray away from the right wheel of the wheelchair. When needed for use, Emma grabs the knob (shown on the right of figure 1a) and slides the aluminum bar forward while simultaneously disengaging the tray’s front arm from the front bolt. She then rotates the tray over her lap towards the usage position, as shown in Figure 1b. Notice that the knob is now below the client’s left shoulder. When the tray is fully horizontal, the tray rests on the wheelchair armrests and is additionally supported by the aluminum bars on either side. The tray is held into place with a magnet on the left aluminum bar that attaches to a magnet on the underside of the tray. There is also a hole in the front right of the tray that falls onto the front bolt.
The aluminum bars are connected to polyoxymethylene (Delrin) clamps that are attached to the wheelchair armrests with countersunk screws. Polyoxymethylene is used to reduce the friction created by the sliding aluminum bars. To remove the device from the wheelchair, a parent or teacher can remove the clamps by unscrewing the cap nuts on the inside of the armrests. The clamp has a window that prevents rotation of the bar until the screws in the aluminum bar are outside of the window (which is achieved by pushing the bar forward). The tray is made of impact resistant polycarbonate—durable, relatively light, and easily cleaned. Its dimensions are 19”x19”, with a U-cutout of 8.5”x15”. It is reinforced with aluminum L-brackets on the front and sides to protect the tray if it is dropped. The edges of the aluminum are covered with Sugru, a rubbery silicone, which protects Emma and other students from the metal.
Emma will use the 8”x9.5” storage bag to carry items such as pencils, erasers, folders, and books. The bag is made of canvas, with plastic inserts at the opening to give rigidity to the structure. The built-in pencil pouch has a small plastic clip to hold it open for easy access. The bag is attached to Emma’s wheelchair armrest with two snap fastener straps.
A commercial water bottle holder was modified for Emma’s use. The Travelon water bottle holder has an expandable pouch for different sized water bottles. A 3” diameter PVC insert holds the pouch wide open for most sizes. Easily adjustable and replaceable zip ties allow the holder to strap on to Emma’s chair behind her left shoulder. A hook attached to her wheelchair handle keeps the water bottle holder vertical and prevents it from rotating behind the chair.
The total cost of this device is $220.
Figure 2: The client using her lap tray at home