Well Windlass

My second project consists of designing and creating a well windlass made out of Delrin, which spans a 12 cm gap. My partner and I went through several designs before coming up with one we thought was effective with only 500 cm^2 of Delrin. First, we thought of using pulleys in a box-shaped frame:

However, we realized that with the pulleys in the center of the box, the weight would not be able to be pulled up ten centimeters above the table, which was one of the contraints. Also, the hole at the bottom of the box would not be big enough to fit the weight through it. Next, we thought of a triangular shaped frame so that we would not have to worry about our piece collapsing with the weight of the bottle we were trying to pull up.

However, this also didn't satisfy the 10 cm constraint and we decided it used a lot of unnecessary Delrin. Finally, we decided on a design using a notched wheel that would span the 12 cm and contained a crank to wind up the string:

 

Our piece consists of five unique parts, bonded together using press fit or piano wire. My partner and I had to make several different test pieces to get the right level of tightness for our press fit pieces, and it took a lot of measuring and re-measuring, due to the discrepancy between SolidWorks and real life measurements.

However, we finally got the right fit and were able to print out our pieces. While originally, our windlass featured two semi-circular grooves which would hold the spinning rod, we decided to instead make loose-fit holes to put the rod in so that there was less of a chance of it slipping out. Our final iteration also differed from our foam core model in that we used piano wire to secure the Delrin rod to the casing around it. In our foam model, the rod was a tight fit inside the casing and the wheel spun with the rod when the crank was turned. However in practice, with the weight of the bottle, the rod ended up spinning in place without turning the wheel. Another issue we encountered was that the two base pieces kept sliding in opposite direction because of the loose fit hole. We then secured the two pieces with a long piece of piano wire and the problem was solved. Here is our final product:

We made the crank long relative to the rest of the device in order to reduce the force one needs to wind up the string. Here is a video of the string winding up with no weight attached to it to show the general function of the windlass.

All in all, I am very pleased with the design we came up with and the effort we put in to make a successful final windlass, staying under the limit of 500 cm^2 of material.