spring finger

Featherboards are sprung fingers that apply downward pressure to hold the workpiece against the table.

In 1871 a perforated cardboard book was substituted for the barrel, but it was still read using sprung fingers.

Hunt & Bradish of the USA, 1849, used a roll read by sprung fingers, the springs being strong enough to operate the piano mechanism directly.

In 1876, John McTammany exhibited a working player in Philadelphia that used a paper roll read using sprung fingers whose slight movement triggered a mechanical player device.

When the select and then the hold electromagnets operate in sequence to move the bars, they trap one of the spring fingers to close the contacts beneath the point where two bars cross.