Assignment 3: Mechanisms

There is something very pleasing about watching gear mechanisms work in an infinite loop!

Browsing through Cornell's Kinematic Models for Design Digital Library, there were so many interesting mechanisms.

I found Model: O05 Planetary Gear, Slider-Crank Kinematic Chain from Cornell's Reuleaux Collection very compelling.

Planetary gear trains (or epicyclic gear trains) are not attached to fixed bodies.  Instead, the links holding the center of the gears move.  Since all the links can move, the train value can be changed by using different gears or carriers. This functionality makes planetary gear trains useful in automotive transmissions.

Below is an image of a basic planetary gear train.

https://memechanicalengineering.files.wordpress.com/2014/02/machines-and-mechanisms.pdf

The central gear (1) is called the sun gear.  The planet gear (3) revolves around the sun, hence the name planetary gear.  The carrier (2) holds the planets in orbit around the sun.This sun/planet gear system is usually inclosed in a ring gear (4).

http://kmoddl.library.cornell.edu/stillImages/small/O05.jpg

In Model O05 from Cornell's library, "there are five links. The fixed base holds two revolute joints. The sliding guide is constrained to the base by one of the revolute joints and constrained to the rod that is fixed to the larger gear. The pinion gear is affixed to another link that rotates on a revolute joint at the base. Finally, there is a link connecting the two gear wheels by two revolute joints. The model is designed so that it can be removed from its base and the large gear fixed as a sun gear and the pinion roll as a planet gear. The pinion has 26 teeth and the larger gear as 52 teeth."

Another gear mechanism I found very beautiful involves its application to art, which can bee seen in this video: