Week 6: Gearing Up!
Sumin S -
Hey everyone! Welcome back to Week 6 of my Senior Project blog! This week has been all about gears, knobs, and figuring out how to get the microscope camera on my spin coder to move. My main goal for this week was to research and have a rough draft of a height-adjustable microscope camera that can smoothly slide up and down on the spin coder for clear, instant imaging. At first, it sounded very simple since the camera just needed to move up and down, but it turned out as a very tricky research with many details.
I started off by learning how most microscopes adjust their height. That’s when I found out about the fine and coarse adjustment knob mechanism, something pretty much every microscope uses. It’s that classic two-knob system where one makes big movements (coarse) and the other makes tiny, precise shifts (fine). If you remember adjusting microscope using a knob from biology lab, that is fine and coarse adjustment mechanism. While exploring how these knobs work, I found something super interesting called the microscope bracket.
A microscope bracket uses a gear mechanism to raise or lower the body of the microscope along a support column. That got me thinking, why not design a similar bracket for my spin coder camera? If I can make the microscope move up and down with a smooth gear system, it would be much easier to capture that instant image of a sample.
As I kept researching, I came across the concept of the worm gear fine adjustment. According to a study by Frank Burgess, worm gears are great for high precision tasks because of their self-locking nature and smooth rotation control (Burgess, 1912). Specifically, Figure 4 of the paper shows a worm gear system that engages with a gear wheel to create a finely-tuned vertical adjustment, exactly what I need for my microscope camera! It offers high torque at low speed, which means it can move the microscope with very delicate precision, and it won’t slip out of place once I set it.
I also learned about the rack and pinion gear mechanism, which is another method often used in microscopes. Here’s how it works: the rack is a straight, toothed bar, and the pinion is a small gear that rotates against it. When the pinion spins, it drives the rack in a linear direction, basically converting rotational motion into vertical movement. It’s a pretty efficient design and makes height adjustments smooth.
While comparing gear types, I also looked into spur gears and helical gears. Spur gears are the simplest, they have straight teeth and work well at lower speeds, but they can be noisy and less smooth. Helical gears, on the other hand, have angled teeth that engage more gradually. This means they’re quieter, smoother, and capable of carrying more load. So for my spin coder’s microscope mount, helical gears would be the better option, especially when paired with a worm gear for fine-tuning.
So, I have learned a lot about gear mechanisms this week! I’ve decided to go forward with a worm gear fine adjustment mechanism, inspired by microscope brackets and enhanced with helical gears for smoother operation. I’m also keeping the rack and pinion system in mind as a backup option. I’m so excited to start designing and testing it out on the spin coder. See you next week!
References:
Burgess, F. (1912). WORM AND HELICAL GEARS AS APPLIED TO REAR AXLES. Transactions (Society of Automobile Engineers), 7, 196–215. http://www.jstor.org /stable/44554623
Comments:
All viewpoints are welcome but profane, threatening, disrespectful, or harassing comments will not be tolerated and are subject to moderation up to, and including, full deletion.