A nuts shelling machine in which a rotary drive mechanism operates a rotary feed mechanism and a rotary shelling mechanism, the shelling mechanism having a frame with four shafts arranged in spaced, side by side, upper and lower pairs, the shafts having surface lobes and indentions for enlarging and contracting the effective space between the upper pair and lower pair of shaft for accepting and trapping a nut between the pair of upper shafts and lower shafts, where it is shelled by a shafting implement before the shell and nut passes between the pair of lower shafts.

http://www.gelgoogmachine.com/peanut-butter-machinery/shelling-machine/