Well, yeah, it has some gears... This project actually started as a requirement in a machine trades course to make a spur gear. Rather than make a useless aluminum spur gear I got permission to make a steel anti-backlash gear for grading.
An anti-backlash gear is actually two identical gears, one riding on the same hub as the other, fitted with a spring (or in this case, 3 springs) to squeeze the gear's teeth together on the pinion gear that drives it. This eliminates any backlash in the mesh.
So, the heart of the R.A. drive is this ~11-inch diameter, 144-tooth anti-backlash gear, which is fitted with three strong springs to put the bite on two separate pinions, mounted on opposite sides of the polar shaft.
Each of the two pinions are driven by 120-tooth worm gears, which in turn are driven by right-angle gear sets, which in turn are driven by reduction gears affixed to a pair of synchronous AC motors.
So in effect, backlash is eliminated and periodic error is split between two separate drive trains. The beast was permanently mounted outdoors and served faithfully for many years, solid as a rock with any scope you cared to put on it, but it is the very antithesis of portability or efficient use of materials.
A huge mistake, but a great learning experience.
Edited by NinePlanets, 01 October 2022 - 10:44 AM.