Hello, I’ve created this post in response to a request for a 1-on-1 discussion about rack gears in VEX EXP.
At its core, think of a rack gear as a flattened out circular gear. Instead of teeth that curve around a circle, the rack gear boasts teeth in a straight line, transforming rotational motion into linear motion when paired with a pinion (another fancy word for gear). It’s like unrolling a regular gear until it becomes flat!
The most distinct advantage of using a rack and pinion system is its ability to convert rotational motion from the pinion into smooth linear motion in the rack. This linear movement is predictable, repeatable, and can be very precise, making it perfect for tasks where precision and control are paramount. Here are two applications for the rack and pinion assembly:
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Indexers: One of the primary applications for rack and pinion systems is in indexing. This is the process of moving an item or piece to a fixed distance or position with precision. By utilizing the linear movement offered by the rack gear, paired with the precise rotation of the pinion, we can achieve accurate indexing in our robotic systems.
An example of an indexer could be a feeder mechanism. Using a flywheel to launch game objects at a high rate of speed? Use a rack and pinion indexer assembly to seamlessly and quickly insert the game object! Here is a 3D model to better visualize rack and pinion assemblies. Note that this build includes V5 Kit components.
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Lift Systems: Elevate your robot’s capabilities, literally! Rack and pinions are often utilized in lift systems. Whether it’s for lifting an object to a certain height or adjusting the angle of a component, the system’s predictable and controlled linear motion is invaluable.
An example of a lift system turns the indexer on its axis, literally! In this article from the VEX Library, a linear slide is shown off. Note that this build was made a while ago, so I will be redoing the images found within it and replace them with 3D versions to better understand what is happening, as well as be able to be built with EXP components.
In conclusion, rack and pinion systems offer remarkable versatility and precision, making them an invaluable asset in the world of VEX Robotics. While we currently don’t have specific builds showcasing this assembly, we’re eager to create something if there’s interest. Your feedback and suggestions are always welcomed. And remember, if you’d like a deeper dive or have more questions, our 1-on-1 sessions are available to you!
