A dwell mechanism that makes use of epicyclic gears and a 4-bars mechanism. The gears describe a particular triangular curve. One of the bars has its lenght equal to the radius of that curve. When one end of this bar is positioned at the center of the curve, it rotates without translation, so the last bar (output) does not move.
Video at https://youtu.be/ioispEgzh20.
Scheme at https://br.pinterest.com/pin/479070479118564342.