Final Prototypes + Meeting with Jaden

On Wednesday we finalized our ideas and came up with a couple of sacrificial concepts before our meeting with Jayden.

Also, the 3D printed part I modeled last week is finished printing, and we added in the bolts just to have a finished prototype even though we scrapped the idea. The size and spacing of the holes were pretty accurate which I was happy about, and I learned a lot about SolidWorks and modeling through the process.

Final HandleStopper permanent attachment prototype.

The second prototype we showed Jayden was a sacrificial idea. It made use of magnets and wood to keep the cord in place. The cord would be sandwiched between the two pieces of wood, holding it in place. This idea was not practical for a few reasons. First, it was really difficult to get the magnets to align properly. Secondly, even if they were aligned, they didn't have the strength to stop the momentum of a dropped chain.





Another idea that utilized magnetics was the prototype Alex had been working on for the past few weeks. After adding foam padding to the inside, it didn't fit over the cord as well as perform. It also didn't pass our "chain drop test".

We also went back to the original idea of simply slicing a sphere in half. We modified a red plastic ball and fitted it over the erg chain. It worked surprisingly well and didn't fall off even after we let go of the handle at full resistance (10) while sitting on the erg seat. Jayden liked the idea of the sphere the most out of all our prototypes, especially since CRI can make their own using balls such as tennis balls.

Sliced sphere prototype

 After our meeting we have decided to move further with the sphere concept. We ordered a bunch of spheres and will cut/drill, and test them over the next week. Our goal is to have a few viable ball options before our visit to CRI.

Variety of balls ready for testing

Prototyping Part 2

Alex and I have made good progress with the prototypes. We have sent both ideas to CRI for review. 

This past few weeks we have been ordering parts, making 3D models of our prototypes. So far we still have two different concepts we have been working on separately, but by next week, after we receive feedback from community rowing, we should know which concept we should invest all our time to.

Our first idea is to make a simple stopper that prevents the chain from snapping into the machine. Alex has created a prototype out of wood and magnets.

Prototype of Idea 1 in wood

The idea is that the two pieces will "clamp" the chain and act as a border so the chain doesn't retract and damage the erg.

Sketch of Idea 1

Before making the prototypes out of wood, Alex and I tried to 3D print them but we were having issues with that process. The built plate wasn't heating up properly so the plastic wasn't sticking. We aren't sure whether that's an issue with the printer settings or with the model.

3D models made in TinkerCAD

Our second idea was to create a cord stopper that also  made the process of replacing the handle easier. The stopper would stay on the machine and allow the handles to be interchanged without any tools. One side of the stopper would hold the chain and the other a bolt that can attach to any handle needed.

 

We 3D printed the model and it came out fine, but there were a few issues with the underside of it. We also had to scale it down to make it easier to print. We will be printing a final model this week.

Sketch of Idea 2

 

 Overall we are in good shape and it's just a matter of hearing CRI's feedback to that we can move forward with a final product.