US Patent 7448591 Step ratchet mechanism

A step ratchet mechanism that allows for the incremental movement of an assembly that may be adapted to incrementally open or close an adjustable orifice. The step ratchet mechanism may be comprised of a modified body lock ring that permits incremental movement along a mandrel in either direction along the mandrel. The step ratchet mechanism may be actuated a designated distance by the application of pressure to the mechanism. The step ratchet mechanism may be ideal for using pressure to drive a downhole multi-position device. The modified body lock ring is adapted to both secure the mechanism at each set position as the mandrel is pumped down as well as allowing the mechanism to ratchet when the mandrel is pumped back.