Well Windlass

Our challenge for this assignment was to create a well windlass – a device that goes over a well and can lift a “bucket of water” via a crankshaft.

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In our case, we had to lift a 1 liter bottle of water so that the top 10 cm of the bottle is lifted above the tables. The success of our project depended on the windlass’ ability to lift the bottle without it shaking or breaking the device as well as it’s ability to lift the bucket within a time frame of 45 seconds. To accomplish this task we were given a 50 cm Delrin rod and limited to 500 cm^2 of Delrin sheet for the final prototype.

The first issue my partner, Marissa, and I tackled was the issue of how to lift up the bottle without breaking the device. With a limited amount of Delrin rod, we had to find some way the maximize it’s usage. We knew that we had to cut the rod up and create a circular shape for the string to wrap around, but we were concerned about whether one rod would be able to withstand the weight of the bottle. What we decided to do was to cut the rod in three equal length pieces and to keep them together in a bunch because we felt that together as a thicker rod they would be able to withstand the force of the bottle. To combat the issue of whether the bottle would be pulled up in the time required, we decided to wrap the rod in a outer shell that would increase the circumference of the rod. We decided that the best shape for this shell would be something that closely resembled a circle and ended up creating a hexagonal shell whose sides would be piano wired together.

Having agreed on what to do with the rod, we decided to tackle the

issue of what to do with the rest of the structure. From previous experiences in physics based bridge building games, I know that triangles are much stronger than any other polygon because, geometrically, the angle of a triangle is determined by it’s opposite side length. In comparison, the angles of other polygons can be changed/altered without changing the length of the sides. So in our structure we decided to support the windlass on a triangle with another triangle to support it from the side, creating a variation on a right angled pyramid.

From there, we attached the structure to a square base because we wanted to maximize the contact
area of the windlass with the table. As added protection against the device slipping or sliding, we decided to create a piece that would wrap under the table. We added multiple peg holes so that it could be adaptable to varying table heights.

The last piece to our prototype was the handle. We didn’t want to make an extension of the rod into a handle because we know that a lever would make rotating the rod much easier. To create a lever we decided to create a piece that would slip over the rod and connect the actual handle piece to the device.

Our Good Friend
the Drill Press

Building the Hexagon's
Sides on SolidWorks

The hexagonal shell didn’t turn out exactly like we would’ve like because the drill bit wasn’t long enough to drill through the entire length of the shell. So instead, we made holes and both ends of each side. As a result, the holes didn’t line up as well as we hoped. However, the shell served it’s purpose, but it wasn’t as uniform or as nice looking as we had anticipated.

After creating the first iteration of our prototype, we realized that through some mathematical error, we ended up usually about twice the amount of delrin that we were allowed. :( Oops. So for our second iteration of halved the size of the clamp piece that extends under the table and made cut outs on the pieces, wherever, it was possible. The only thing we kept the same was the hexagonal shell.

Melissa and I really scrambled to create our final piece as a result of our mathematical error. Since
we didn’t realize our mistake until Tuesday the 16th, we only had three days left to reprint everything and troubleshoot. We didn’t end up being able to fix everything, but we did manage to make a few edits to our design. For stability, we ended up added two more pieces of support halfway down the triangles because the triangles were leaning inward a little. We also put in some piano wire at the base of the triangle in order to ensure that the structure wouldn't topple during use. While our windlass succeeded in lifting up the water bottle, the rod was prone to falling out of the handle. If we had more time on this project, we would have heat staked the rod to the handle so that it wouldn't be able to fall out. Since we forgot to take into consideration the table's legs when taking measurements, we were only able to use one of the stabilizers that held the windlass in place, to fix this we would definitely remeasure and made edits to the piece that wrapped under the table and heat stake the rod to the handle.

Our final design post presentation

Watching the other group's presentations was really interesting. Unlike in the bottle opener assignment there was a far greater variation in creations. There was no one way to create a windlass, although some designs were definitely greater than others. If given the chance to produce a complete overhaul, I would definitely rethink the usage of the rod's and try to produce a larger circumference by spacing out the rod's since it seems our initial worry that the rods by themselves wouldn't be enough to support the weight of the bottle.

Overall, our windlass used up about 540 cm^2 of Delrin, which is above the limit by 40 cm^2.

If we could do another rendition of the windless, we would first need to shorten the piece that locks in under the table because we originally forgot to account for the table’s leg. That would take off about 5 cm^2, bringing us to a new total to roughly 535 cm^2. We could use less Delrin by halving the part that slips under the table. That would take off about 60 cm^2 of Delrin, which would bring our new total to roughly 475 cm^2 of Delrin. Finally, we could also cut a hole out of the center of the handle’s, which would then definitely drop our total Delrin usage to around 470 cm^2.

My partner and I really struggled with this project as a result of our mathematical error, which is rather unfortunate. We both learned a pretty big lesson from this assignment – if we were more careful during our brainstorming process or had double checked along the way, we could’ve avoided a lot of stress and tears. Regardless, I think it's pretty cool that we managed to design and construct a windlass within two weeks!