Hi all, the unknown rotary pump is indeed an Ampico pump from the
Stoddard years. I have an operational one in our 1918 Stoddard Ampico
upright piano. According to the serial number, the piano was actually
made by the Foster Company but the fall board has Stoddard Ampico
emblazoned in the center. In the upper right corner of the piano
plate a small plate has been placed over the corner of the original
plate and this added piece also proudly states Stoddard Ampico.
The pump itself has cast metal arms with ball bearings at both ends
and a cone-shaped center to adjust the amount of play by the loose
balls in the bearings. On the right side of the pump there is a
reservoir which has an adjustable spill valve to limit the amount of
vacuum which is allowed into the system.
The piano which it is in is a Type IIb (2B) Stoddard, I believe.
I am currently out of town so I can't give you the definitive version
of the Stoddard in which it resides, but I am certain that it is a
type II of some sort. I hope that this info helps out. If you'd like
to see pictures of the piano I'd be happy to oblige.