Final Product: Oar Connecter
Abstract:
The issue we wanted to tackle was making wheelchair riders more independent when accessing and transporting their oars to and from the boathouse and docks. This product was meant for wheelchair riders to freely access their oars and carry them without the help of a volunteer. Through our journey to create such a product, we made three distinct prototypes. Our preliminary product was a swinging arm on each side of the chair to carry the oars. Our second product, which we spent the most time on, was the backpack oar carrier. We learned of the problems associated with both of our products and decided to take a step back. Our final product was geared more towards easing the way the oars are carried now by some riders rather than completely making them independent through the use of an oar carrier. Although the final product did not create a method to carry the oars easily and independently, it aids the way the oars are currently being held. We hope our research and failures to creating a product to make oar carrying completely independent will be beneficial to other engineers in training.
Problem Statement:
Our goal was to design an oar carrier for our community partner Community Rowing Inc. The idea behind designing this product was to facilitate a wheelchair rider’s process of carrying equipment out to the water in order to decrease such rowers’ need for volunteer aide and simultaneously create an increased sense of independence for the rower.
Design Specifications:
- Hold 2 oars as close as possible to each other
- Make 2 separate oars into one unit
- 2 holes to put oars into - Triangular side and flat side to make hole
- Separate sides of unit to take apart and screw together
Design Concept Ideas:
- Swinging Arms: The initial idea we created a 3D model for was to put an arm on each side of a wheelchair that each oar could be attached to. The arms would swing back and forth in order for a person who can’t move around much to be able to reach the area where they need to attach the oar to and then be able to swing it back so its not in the person’s way. However, we found, with Professor Banzaert’s insight, that this idea had 90% chance of not working (perhaps more, but I still have a little faith in it :)). This idea would have altered the center of mass which would have too many unintended consequences for our prospective user. The wheelchair would have been at a greater risk of tipping over with the weight of the oars when going up and down a ramp. Furthermore, when first brainstorming the idea for this product we didn’t have the oars with us so we didn’t realize that the oars were too long for this idea to have worked anyway.
- Backpack: The second idea that we went forward with, to the point of showing Jaden and having her test it, was an oar carrying backpack that could either be hung on a wheelchair or on a the rider’s back. (This idea could maybe work if further developed.) The issues we found were that the material we used (3 in. PVC) was much too heavy for anyone to comfortably carry. Furthermore, once again the length of the oars proved to be a problem as the oars would tip forward, but of course the length of the oars was a problem we couldn’t fix. We weren’t working on redesigning oars anyway! Jaden also informed us that she and other rowers already carried backpacks when going out to the water with their medical equipment so adding another item to their back would not have worked. The biggest issue with the oar carrying backpack, however, was that when Jaden finally came over to test out the product herself she informed us that getting the oars behind her back in order to place it into the oar carrier was near impossible for many wheelchair bound rowers. A lot of them may not have the core muscle strength, or leg strength (some people are missing thighs which does make the process more difficult), or ab strength it takes in order to pick up those oars where they need to be picked up from. Though they may seem light, it really does take a huge amount of strength to pick those long tubes up and over your head in order to put them into the pack behind your back. Professor Banzaert, Atiya, and I also struggled to put the oars into the backpack a bit in the beginning, but with some practice it became a much easier task so we thought that any rower would be able to do the same with much less effort than what we had to put in. Thankfully, Jaden let us know that there were many more difficulties to think about. So in the end we had to trash this idea too.
- Oar Sling/Diagonal Carrier: This was an idea that Jaden had suggested when she came to test out our products in April. She mentioned that some rowers carried their oars diagonally so we decided to play around with the idea of a sling (like a guitar strap) that one could attach an oar to and put it around their neck and then on their lap. When we were first thinking through the idea we were only focusing on one oar so it didn’t fully dawn on us that the person would need to be carrying two oars until we mentioned our idea to the class. This was probably our worst idea quite honestly. Once again oar length is a huge factor to take into consideration here. There is no way to carry two oars comfortably around one’s body unless the oar is redesigned to be able to shrink….(but hey maybe you future students can think of a way! If so, props to you. We now leave it to the future.)
We decided on our final oar holder idea because we were at the end of the semester and we had exhausted our minds with trying to find a solution to this problem unfortunately. After Jaden came to visit us in April and we realized we had to start all over, we decided to go visit CRI because we needed a fresh look at things once again. We were, at that point, in the process of testing out our strap idea. While at CRI we completely decided to leave the strap idea behind though we weren’t exactly sure how we were going to move forward. Jaden and and a fellow rower were kind enough to meet with us and they each showed us how they carry the particular oars they use at CRI (which are a bit smaller than the ones we had to work with). Jaden for now carries her oars between her legs so she mentioned and/or we observed that a problem she has with that is that the oars could tip forward as she speeds along. So we decided that since we couldn’t do much on the oar carrying front for now, we would move our focus to fixing an issue within the bigger picture. Having a way to keep the two oars together would hopefully resolve the issue a bit.
Methodologies and results of tests we performed in designing and refining our prototype:
As expected most of our time was spent testing out our various products. We would take whatever we had available at the moment, whether it be a cardboard model or the actual prototype and sit on the We-Lab's wheelchair or connect our product to the oars and test out every possible scenario ourselves trying to put ourselves in the shoes of the potential user. Results of initial prototype tests have been mentioned previously and in past blog posts. For our final product, we began by drawing our vision of the product out on paper. We then went over the design idea with our professor who helped us flesh out how the product should be connected and what how we should calculate what the exact measurements of the product should be. Since we were dealing with a range of oar diameters (as mentioned above, Jaden's oars are slightly smaller than the oars we were borrowing from the crew team here at Wellesley), Larry had been the one to suggest that we make our product in a v-shape as to cater to the various diameters (our original idea was to do a cylindrical shaped grooves). After we had made our calculations we decided to make a cardboard model of our product (we were experts at cardboard models at this point) before we started cutting and bending any metal. Once we felt that we had our measurements down (especially for the center part that would separate the two oars since we knew we couldn't measure much without exact angles in a cardboard model) we moved on to making our first prototype. Our first prototype was not perfect at all of course, in fact it ended up breaking on us. It was made of a not so malleable metal that couldn't withstand the 90 degree angles we needed to bend the metal to. But we were still able to use that model in order to figure out if we had made the correct measurements. From this first model we were able to see that the distance we had originally set out for center was a bit too wide so we shrunk it down to .75 inches in the future prototypes we made. Larry then helped us pick out a much more malleable metal and with that we made our final products. In between making final, finished products there was a lot of playing around with trying to get the perfect 90 and 45 degree angles, but the more models we made, the more efficient we became at figuring out when we had reached the perfect angle.
Detailed Design Specifications
Our oar connector is made of 6 parts- the straight metal side, the shaped metal side, a screw, nut, and wingnut. The measured side and straight side would both have a hole in the center and be connected by the screw. The nut would be in between the two to make it more secure and the wingnut would be placed on the straight side so it is easy to spin. The wingnut would be spun to open and close the connector. When the wingnut is taken off, then the straightedge can spin on the screw to be vertical. When vertical, the oars can be inserted or removed. And to finish the process, the wingnut would be placed back on to close connector.
For future reference:
Oar diameter of W. sculling oars: ~1.8 in.
Oar diameter of Jaden's oars: ~1.4 in.
Info provided by Jenny from CRI:
Jaden's oar diameter is:
At 13.4 cm distance from the blade side of the end of the sheath- diameter= 4.4 cm
At 21.9 cm distance from the blade side of the end of the sheath- diameter= 3.7 cm
(We think she probably made a slight typo in the email, so we just went with the smaller diameter when making our calculations.)
The oar is 277.4 cm from end to end.
Extent to which our final design meets the design specifications: Our final design met the specifications that we created to make an oar connector or holder as the rider is carrying them. However, this was not the original problem of making an actual oar carrier. Future teams who take on this project can perhaps build upon what has already been done and think of even more creative ways to solve the problem.
How our design has been received by your community partner, what follow up is needed (prototype delivery, etc.), and how that will be achieved: The prototype is still in the process of being delivered to CRI. Feedback will hopefully be received shortly.
And finally a special thank you to everyone who made this semester possible: Jenny, Jaden, CRI members, Tessa, Professor Banzaert (thanks for dealing with all of our questions however silly they may have seemed), and Larry for giving us so much of his time in the workshop and his never ending support and encouragement! Thank you. We not only learned so much, but we had so much fun stressing about this project.
