The Adaptive Swimming Device (ASD) was created as an apparatus that could sustain positive buoyancy for children with atypical development. The device supports children ages 12-22 who weigh anywhere from 60-230 pounds with various physical and intellectual challenges including, but not limited to, quadriplegia, paraplegia, diplegia, hemiplegia, Amelia, amputations, autism, cerebral palsy, and vision impairment. The device is optimally designed to allow the user to either float or swim with a horizontal, face down orientation. They are be able to develop their swimming abilities beyond current capabilities. The device will only be used in an environment where a certified instructor is giving individual attention to the user in an indoor pool with lifeguards to ensure safety of the child.
Proof of Concept
The Proof of Concept (PoC) was used as a design analysis to test concepts for a preliminary device design. The PoC that was employed by the team was created by building a main base of the swimming device. By having a main frame, concepts could easily be tested once the general frame was proven to float and give buoyancy to the user. It was determined that it would be easiest to create the frame at full scale using parts and assembly that could optimally be reused for the final design. The main frame needed to be perfected for flotation to ensure that the user and the sponsor would have full support and safety while using the ASD.
Measurements that were used for the ASD were taken from testing as well as measurement of different appendages of the user. The measurements were based on an average 5′ 5″ tall person for arm extension and all measurements were used for width, length, and depth of the device. It was not of utmost concern to get perfect measurements so a lot were inferred from general knowledge and assumptions as the design would be redone later on. Calculations were then made for the appropriate geometry to match the requirements set forth in the CAD modeling as shown below.
Schedule 40 PVC pipe was used for the fabrication of the main bars of the base frame. Schedule 40 PVC connections were used as the connecting joints between each pipe. Each pipe was cut to specifications as detailed by the CAD design and calculations made to account for the extension of each joint so everything would be of proper dimensions. The pieces were then fit together as specified by the CAD model to form the main frame of the device, not including the board. All parts used and the assembly process are shown below.
After the assembly was completed, a board was added to the top of the device in the designated area using a connector joint and bolts. The joints were then connected using a temporary glue to prevent rotation during testing that would not be present otherwise. The board and the glue were added to allow for testing in a pool. The main testing categories for the PoC were buoyancy, bending of the base bar, clearance. maneuverability, drag, accessibility, comfort, and portability. The testing categories were selected for either the safety of the user or to test engineering analysis calculations that included an infinite amount of possibilities that could not all be accounted for. Unknown calculation circumstances were caused by the infinite amount of movements a user could potentially do on the device that could not be solidly calculated through equations.
The testing was done with three different people of different weights: 120 pounds, 150 pounds, and 300 pounds. Each person sat on the board or tried to swim with the device to create movements to perform the different tests necessary to gather information for the PoC. The pictures from the testing are shown below and a video of a testing situation will be posted shortly. In the pictures, the woman in the pink shirt is the 120 pound weight force, the woman in the green swimsuit is the 150 pound force, and the man in the blue Nevada shirt and gray shorts is the 300 pound force. Those that are underwater during the use of the device are measuring the clearance and the bending of the base bar. The device gave promising results for the PoC and worked better than expected. Some changes needed to be made during the testing but further development must occur to better the device. The results and expectations are shown below.
Overview of the Design
Design modifications were made from the Proof of Concept to ensure a better device for the safety and ease of use by both the students and their certified instructors. To better meet the objectives and specifications, a few elements were added or changed. The overview of the design will show and explain all of the elements of the Adapted Swimming Device. The complete conceptual device is shown in the picture below.
One of the main changes to the frame to better meet the specifications and objectives was that the height of the frame were shortened to approximately 21″ for better storage and portability. The height change was done to all three of the supporting arms, which also allowed for the smaller board to be able to fit on the frame without issue. The other change was the float support bars. They were originally designed to be stable and permanently in place, but they were redesigned to be collapsible so less space would be occupied during transportation. A bungee cord runs through each support arm and attaches to the opposite sides where end caps how the bungee cords in place so they are not be easy to remove. The two ends are able to be stretched out of place and folded over to be contained in line with the middle part of the bar. All three parts on each side are held together using another bungee cord. Using a bungee cord allows for quick set up and take down of the device without creating extra pinch points or overly complicated assemblies with small pieces.
The floats are each made of eight standard pool noodles (although six is within an allowed range for proper safety) in a mesh netting sleeve that are form fitting so the noodles will not slip out if the instructors wants to take them off. The noodles are contained within the bag by a drawstring to allow easy removal of noodles if they start to decay or if the weight needs to be adjusted. Each float has three Velcro straps that are attached around the PVC pipes as well as the noodle floats so that they can be quickly removed or assembled without a lot of hassle. The floats will each hold approximately 150 pounds, and with the device, is able to hold 300 pounds safely.
The board, which is the part of the device the user will actually be laying on, changed size and material from the Proof of Concept. The board is 10″ wide by 20″ tall by ~2″ thick. The 10″ width can comfortably support a person from a small female to a large male because of the average shoulder width. The 20″ height board will also fit most people (although in varying places) between their shoulders and theirs hips without causing any constriction of range of movement. The ergonomic shape, as well as the dimensions, allow for optimal movement without sacrificing too much comfort. The board is made from High Density Polyethylene (HDPE) which is able to hold the range of weights that are used on the device without deforming.
The plastic is also able to withstand the effects of chlorinated water. The board was covered in polyethylene to support the user without giving them a hard surface to lay upon. If the foam was too soft, then the user would have to work harder to keep themselves steady on the device, which may be beyond their abilities. The board was attached by screw on flanges so that the board will not be easily removed by pulling. Female buckle components are also attached underneath the board for easy access to be able to easily attach or detach the flotation attachments. The location on the bottom makes it easy for the instructor to reach, but not the user, so they will not be able to unintentionally release the devices. Finally, there is a strap that can also be attached by buckle that can be tightened to keep the user in place if so desired. It will allow them to get out easily in the case of an emergency but keep them in place so they don’t slide off while learning to swim.
The attachments were new from the Proof of Concept and were crucial to the use of the device. If one of the users are not capable of using their arms or their legs due to paralysis, they are not able to keep their appendages from dragging in the water and this results in an extremely uncomfortable activity. It is also hard on the instructor because they have to continuously watch the appendages and try to keep them in an appropriate location. To counteract the issue, different attachments were made for different disabilities. There are two arm rests, a leg rest, and a head rest.
The head rest was made out of layered 3/4″ 4 pound polyethylene foam that was stacked by five layers and cut to form a shape similar to a massage table head rest. If the user is not able to keep their head out of the water or have their face in the water, then they will be able to comfortably rest while learning to swim without fear of drowning or swallowing water. The arm rests were made out of two noodles that are approximately 13″ long to support the arms comfortably at the sides without creating too much drag if the person is able to kick. The arms fit in the grooves created by the contact point of the two noodles so they will not roll off. The difference for the leg rest comes in the length and structure. The leg rest noodles are approximately 26″ long and has two sheets of polyethylene foam for support. All of the attachments are easily removed because of the growth in ability and the range of disabilities of each user. The Adapted Swimming Device can quickly change to account for many different atypical developments while also allowing modifications based on user abilities.
One of the main issues with the Proof of Concept that needed to be changed was the portability. One of Lorraine Howard’s main expectations was to be able set up, use, and transport the swimming device on her own. All of the components, in the collapsed version, are able to be stored easily in the back of a Jeep Grand Cherokee, which is the car used by Ms. Howard and will be the car that she will be using to transport the device to each of her classes. By making it easier for Ms. Howard to transport the device, set it up, and take it down on her own, she will be able to attend to more students during her sessions while making sure they are safe and comfortable.
The fabrication of the Adaptive Swimming Device used the Proof of Concept as a main base. The Schedule 40 PVC frame that was constructed for the PoC was used for the frame of the final device. The legs were shortened as shown below using a table saw. Once all of the pieces were cut, the frame was re-assembled and all of the PVC bars and connections were glued except for the two joints/four connections on the end bars. The middle piece was glued into place for a strong and stable center, but the ends were left unglued.
To allow for a more collapsible device, bungee cords were added into the side arms of the PVC frame. The two ends of the bars (17.75″) were removed from each side. End caps were added to one side of each PVC pipe. There were two oblong oval cuts made using a drill that ran parallel. One was two inches in length while the other was one inch in length. The end of the bungee cords were hooked pulled through one hole and brought back through the other so the bungee cord would stay in place under tension. The bungee cord was then pulled through the first pipe to the middle pipe and then through the final pipe and latched back through the other end cap in the same fashion as had been done originally. This was done for both sides so the pipes would be held in place but still easily collapsible.
The floats were made using eight noodles of original length on each side of the device. The noodles were bunched together using string while someone held them together. Another person wrapped the mesh fabric around the noodles and added an extra two inches for sewing. The appropriate amount of material was cut to use for the first float and remained in a single piece. There was not enough material left for a complete second mesh bag of appropriate size so three smaller pieces were sewn together to create a properly sized bag. Both flotation bags were sewn together using a hand knotting technique to join the pieces. In every third hole in the mesh, a knot was made to keep the bags securely together. The sides and bottom of the bag were hand sewn. The top of the bag was sewn using a sewing machine and heavy duty thread to fasten a drawstring along the top seam; therefore, the bag could easily be closed or opened by the user for maintenance. All eight noodles were then inserted into each bag for storage and portability as their only function is as the main flotation device.
The arm and leg attachments were made using an extremely similar process to that of the floats. The arm floats were cut to be approximately 13.25″ each as they would be supporting the smallest mass of the body. Two cut noodles were used in each arm float side by side. A different mesh made from screen material was wrapped around the two small noodles and was given two extra inches for sewing. The mesh was then sewn together using heavy duty thread and a sewing machine.
The bags for the arm and leg attachments could both be sewn as they were small enough to run through the machine without issue. The bags were sewn together along all open sides as the arm floats are the only ones that are not easily accessible. This was due to the low predicted usage and the small amounts of material used for fabrication. Two buckles were then sewn 4.5″ apart to match the buckles on the underside of the center of the board. The buckles would be inserted into the top and bottom buckles of the board while leaving the center of the buckles for the strap to go across the body. Two bags were made in this fashion, one for each arm.
The leg floats were made using the same mesh that was used for the arm floats. Six noodles each measuring approximately 26.5″ were set side by side and placed on mesh. The mesh was then folded over and cut to allow for two extra inches on the sides as well as the top and bottom for easier sewing. The sides and bottom of the bag were sewn using heavy duty thread and a sewing machine. A drawstring was sewn into the bag along the top in the same fashion as the arm attachments and float bags. Three strips of half Schedule 40 PVC pipe were then placed in three equally spaced locations in the inside of the bag. They were hand sewn into the top of the bag for stability of the legs once the noodles were inserted. Nylon straps and buckles were added 8.5″ apart on the end of the bag that was sewn closed.Unfortunately, after testing, the PVC had to be cut out from the bag and a sheet of four pound polyethylene that was the same dimension as the bag was placed under the noodles for stability. The PVC was not able to support the added weight of the legs as originally intended, so modifications needed to be made.
The head rest was fabricated using adhesive spray, four pound polyethylene foam, nylon straps, buckles, neoprene, and a woman’s swimsuit. The sheet of polyethylene foam was only one inch thick and therefore did not have enough buoyancy force to hold up the weight of the head with one layer. A pattern for the headrest was used from one of four options that were tested by the group to provide the most comfort. Five separate layers were constructed using the headrest pattern by cutting out the foam using a box cutter. The layer of adhesive glue was then applied between each layer and a ten pound force was placed on the foam for about an hour for full contact adhesion.
After the glue had dried, the top three layers were shaped using a standard kitchen knife as the original design was too boxy in layers to be considered comfortable. The top three layers were filleted inwards after much testing done by the group to ensure the greatest amount of comfort for the user. Neoprene was then cut using scissors to form around the top layer of the headrest in the same pattern. The neoprene was then glued on using the adhesive spray, and pressure was applied while the glue dried. After the headrest was completely dried, a woman’s swimsuit was cut to completely cover the headrest. The pattern was cut and sewn onto the headrest. After the cover was completely sewn except for an opening on the end, the headrest was slipped into the sleeve and sewn shut. Two nylon straps were sewn to the headrest as shown above at a distance of 8.5″ and could be connected to the top part of the board.
The wooden board from the Proof of Concept was proven not to be comfortable enough for the use of children so it was decided to use a different material and create a more ergonomic shape. A template was laid across the top of a sheet of high density polyethylene (HDPE) that was 10″x 20″ x 0.75″. The template was constructed in AutoCAD so dimensions were accurate and the clips and buckles would be in the correctly corresponding regions to match exactly with the leg and arm floats as well as the head rest. The board was shaped around the template using a router and a straight bit. Once the shape was done, the edges were smoothed and rounded using sand paper. Holes were then drilled in the appropriate areas for the buckles as well as the connecting pieces. The flange bolts on the bottom were counter sunk.
Two layers of four pound (3.4″) polyethylene foam were then added to the top of the HDPE board and shaped using the router. A sheet of neoprene was then placed around the HDPE board with both layers of foam stacked on top. The neoprene was fit around the entire board and cut out using scissors. This ensured a tight fit that would minimize bubbling. The foam was then glued together using adhesive spray and set to dry with applied force to keep the two pieces together. After drying, the neoprene was then glued to the foam pieces. Before setting, the neoprene was wrapped around the board to ensure it was properly adhered. The side of the foam not adhered to the neoprene was then glued to the HDPE board and set to dry. After drying, the neoprene was held taught to remove bubbles and glued along the sides of the foam and HDPE and around the bottom of the HDPE in an extremely similar fashion to wrapping a present. The flange was then secured to the board to hold the neoprene down and tightened using washers and nuts that were hand tightened. The template was then taped again onto the bottom of the board to drill the correct holes for the buckles through the neoprene. Bolts were already in each hole before gluing so a washer needed to be added to hold the bolts into the place. Lock-Tight was added to all flange bolts and they were secured so the neoprene wouldn’t rip but tight enough to keep the nuts from coming undone.
Testing and Results
The Adaptive Swimming Device was tested by two of Lorraine Howard’s students, Hayden and Erin. Hayden has Down’s syndrome while Erin has autism. They both had atypical mental development and there were no students that were willing to test that had atypical physical development. However, Hayden and Erin were wonderful participants to work with and gave the team a lot of insight as to how the device would work. Testing was performed by doing a test that simulated the exact environment of Ms. Howard’s classes. The students were not given any instruction by the team and Ms. Howard directed them as she would in her normal classes. The students were to use the device to swim to one side of the pool and back, which is a total of 50 yards. Due to the nature of their disabilities, the enjoyment of the students was the key indicator of the success of the device.
Each student tested for safety, full range of motion, comfort, and horizontal orientation of the Adaptive Swimming Device. Neither student had an issue with using the device at all as they didn’t slip off or get injured in anyway. Also, they did not swallow water or feel threatened while using the device, showing that it was safe for the students. Next, full range of motion was tested without guidance. The students naturally performed any movements they wished including the butterfly, breast, and freestyle strokes and did not encounter any obstacles to hinder their movement. This proved that the device allowed for full range of motion. Next, the device was comfortable because each student wanted to continue to use it beyond what was required and they were excited to do so. Children will generally not do an activity that causes them pain, so the device was comfortable for each student. Finally, both students wanted to use the device correctly in its horizontal position and felt comfortable doing so. Without instruction from either the team or Ms. Howard, the students got on the device correctly and knew how to use it.
The other objectives that needed to be tested that couldn’t be done by the students were the lightweight, portability, and how well the attachments worked. Lorraine Howard is capable of carrying 50 pounds as given by her job description. She was able to carry the 36 pound device on her own and put it into and take it out of the pool without any trouble. She was also able to carry the device on her own in two trips (for a distance of ~300 yards) and set it up without assistance in a matter of minutes. She approved of the lightweight and portability that the ASD had compared to the PoC and was elated with the ease of transportation. The device was also put into the back of her Jeep Grand Cherokee to ensure that the she would be able to move it to her different swim class locations and there were no exhibited struggles with this action, further proving that the device was lightweight and portable. Finally, the attachments were tested by the team. They were not tested with the students because of the fear they would feel uncomfortable not being able to use their arms or legs and becoming constrained without reason. Therefore, the team tested the device by laying perfectly still on the attachments and allowing another to tow them around. The modified attachments all worked extremely well for the team, so, within the capacity allowed, the attachments were considered successful for the device.
Hayden and Erin were both students who were considered strong swimmers for Ms. Howard’s group, but even they were not able to swim the full 50 yards during one swim session. While testing the device, both Hayden and Erin were able to swim 50 yards three times. They wanted to continue using the device, but the there was a session that was scheduled for the pool so the time restrictions kept them from continuing. This was great news because it showed that each student was extremely eager to use the device and were comfortable with it. The most surprising and inspiring result surfaced at Ms. Howard’s next swim lesson. The team had the device for a presentation so Ms. Lorraine was teaching her class as she did usually. During this class, both Hayden and Erin were able to swim unassisted for 50 yards for the first time. The device helped to boost their confidence and helped them to achieve a goal in one use of the device that they were not able to do with many years of swim lessons.
A table of the results can be seen below, but the true results came from the immediate improvement for Hayden and Erin and the joy they got from their achievements.
The following video is from Lorraine Howard giving her statement about the Adaptive Swimming Device
Meet the Team
Arianna Munro is a Mechanical Engineering senior at the University of Nevada, Reno who is currently working on her bachelor’s degree. She is working as an undergraduate researcher in a lab that studies how organisms with extremely small Reynolds numbers move through their environments. As a Colorado native, she loves to hike, run, swim, bike, compete in triathlons, and play Ultimate Frisbee.
Eyra Herrera is a Mechanical Engineering senior student going to graduate in May 2015. Eyra is eager to finish her academic preparation and start gaining experience in the Mechanical Engineering field. Eyra’s favorite area of Mechanical Engineering is Thermodynamics and any of its applications. One of her biggest dreams is to become part of the engineering force behind the Panama Canal. She enjoys the sun and hanging out on the beach.
Kyle Janofsky is a senior Mechanical Engineering student at the University of Nevada, Reno. He is working on his bachelor’s degree and works part-time at a mechanical engineering firm in Reno. His favorite areas of Mechanical Engineering are fluid mechanics and heat transfer. A native of California, Kyle has always enjoyed outdoor activities such as dirt biking, wake boarding, snowboarding and taking his rescue dog, Xena, to the dog park.
Bianca Saavedra is a senior in Mechanical Engineering at the University of Nevada, Reno. She plans to graduate with her bachelor’s degree in May 2015. Bianca is interested in aviation and is ready to start gaining experience in the field. Her favorite courses have been thermodynamics and dynamics. She was born and raised in Nevada and loves the area. Her hobbies include playing sports, painting, and spending time with family.
Kevin Houle is a senior in Mechanical Engineering, a Disabled Veteran of the U.S. Navy and the former Vice President of Theta Tau Rho Delta chapter, a professional Engineering fraternity. With Kevin’s knowledge of leadership roles and groups he provides a different outlook upon the college group environment. Kevin is studying space technologies to pursue a career in transportation and exploration using future technologies and propulsion different then conventional rockets.