When we initially went about building this device, we thought it essential to understand how a typical horizontal rowing machine works. After viewing how some individuals built their own “at-home” rowing machines (such as Matt Nunan on YouTube), we deconstructed his basic layout and transitioned it into a vertical device. We immediately knew the device should be more compact, and as such, would have a much shorter chain and elastic band than typical DIY rowing machines. Figure 1 shows our initial sketch evaluating the DIY horizontal rowing machine layout. Figures 2 and 4 show our transition from a horizontal layout to a vertical layout. All of these figures display some of the notes we made about the original device, as well as how we thought we should change it. Figure 3 displays drawings of the foot and pulley holding plates that were used in the design.
As some of these earlier designs show, it was quickly decided that the fan should be placed within some form of “housing” or at least “sandwiched” between two sides of a plate to protect both the moving components inside, as well as the user. (Also note the addition of a “handlebar catcher,” which we ultimately did not perfect, but do acknowledge the importance of in an automatic-retractive device such as this).
Figure 1. Horizontal Rowing Machine Layout
Figure 2: Side View Drawing of the Design
Figure 3: Drawings for the Foot and Pulley Holding Plates
Figure 4: Redesigned Vertical Rowing Machine Layout
After this general design was decided on, we moved onto building the first prototype (at a much smaller scale), which is shown in figures 5. and 6. Figure 7 displays a video of our low-resolution prototype in action. The primary goals of this prototype were to generally get a better understanding of how the envisioned mechanism would function, to get a better idea of where various pulleys would be placed to ensure no chain-on-chain contact, and to investigate where the best place for the fan would be.
This initial device was built using drawn parts on the Notability App (pdf) and a laser cutter on ⅛” acrylic. ¼” wooden dowels were used for the axles, and tape was used to create a better fit in the plate holes. A relatively weak elastic band off of a shopping tag for shoes was used in place of both the elastic and chain. A piece of cardstock was used as a common ground for both plates. Glass glue was used to attach the parts to one another.
Building this first prototype was beneficial in multiple ways. While it did help us with the aforementioned goals, it also helped us understand how sturdy the “grounding/support mechanism” would need to be. We had initially not implemented supports into our design, but decided they would be essential in our final prototype. We were also able to assess that the non-rectangular shape of the two outside plates should be made rectangular for increased stability, and that a series of holes would allow for easy layout adjustment in the final build.
Figure 5: Low-Resolution Prototype - Orthogonal View
Figure 6: Low-Resolution Prototype - Top View
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Figure 7: Video of Low Resolution Prototype