Bausch & Lomb's Volute was an advanced standard shutter construction with wider shutter speed range from 3 to 1/150 seconds, plus B and T mode. It had two characteristic pistons, one to connect the tube of the release bulb, the other as part of the speed setting mechanics. For aperture setting it had a built-in iris diaphragm.
|Bausch & Lomb Volute shutter with Ica Extra Rapid Aplanat lens|
image by Luis Cozeto (Image rights)