Patent No. 170,645 (November 30, 1875): Steinway's Regulation Action Pilot, also known as Capstan Screw, lifts the parts that drive the hammer toward the string.
Patent nr. 170.645 (30. november 1875): Steinways Regulation Action Pilot, også kendt som Capstan Screw, løfter den del, der fører hammeren mod strengen.