Differo-Epicyclic

By Spencer Connor

For each of these gearing schemes I present the simplest incarnation possible, and yet differo-epicyclic has 7 gears at a minimum. The reason is that is while most gearing systems are generally, the differo-epicyclic train splits into one conventional gear set (A2 to D1) and one differential gear set (A2 to C1) that recombine to an output (C2 to E1). The conventional gear set can be used as a secondary output (θE), if desired, but this is not necessary.

A Specific Example: Early Astronomical Clocks

This gearing scheme might seem completely overboard, but (especially if the secondary output xx can be used) it can still be the simplest solution for a given design. Take for example the scheme shown on right: Not only does it combine A1 and A2 to a single 29T pinion (bottom right) but it duplicates the E assembly shown above with 80 and 76 teeth for two functions, the nodes and the astrolabe. The 118T gear is fixed to a 29T gear, which then has a 36T idler gear above to mesh to an 18T C1 gear. The primary purpose of the 36T idler gear is to reverse the direction and take up space, it does not modify the rotation speed of C1. C2 is a 4T gear meshing with the two E1 gears (Nodes and Astrolabe) simultaneously. Thus, with only 7 gears four different outputs are generated and with reasonable accuracy no less.