In 1910, an event occurred that revolutionized photography:  two Bausch and Lomb shutter designers, Rudolph Klein and Theodor Brueck (the latter had designed the “Volute” shutter in 1902) filed U.S. Pat. 1,092,110 for a shutter delay mechanism involving a rotating gear and a rocking pallet.  This was the basis for the slow speed escapement that was to make possible the very best leaf shutters of the twentieth century – the Compur, the Copal, the Prontor, and the many, many other fine clockwork shutters that made possible the greatest images of the last century.

Consequently, this patent is reproduced here in its entirety: