ClipArt ETC
"a is the bobbin case; c, bobbin; b, thread wound on bobbin; d, projection from bobbin-case which keeps it from turning; e, thread leading out." —Whitney, 1889

Bobbin Detail of Wheeler and Wilson Sewing Machine

"a is the bobbin case; c, bobbin; b, thread wound on bobbin; d, projection from bobbin-case which keeps…

A device that regulates the flow of a fluid gases, liquids, fluidized solids, or slurries by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category.

Coarse Threading Valve

A device that regulates the flow of a fluid gases, liquids, fluidized solids, or slurries by opening,…

A structure in a hollow organ like the heart with a flap to insure one-way flow of fluid through it

Fine Threading Valve

A structure in a hollow organ like the heart with a flap to insure one-way flow of fluid through it