This combination gives a slow advance and quick return motion to reciprocating bar A. The pin in [the] revolving disk, as it changes position working inside the slotted arm, causes this reciprocating motion.
[Virginia Downward & William M. Clark, 1930]

[Editor’s Note: This is an intermittent mechanism with slow and fast return due to the different moment arm lengths of the rotating disc pin as it reaches the top or bottom of the disc circle. This model was copied from Henry T. Brown's Figure 131, in his 1868 catalog of mechanical movements. FCM]

Francis Moon 2005-00-00