four jaw chuck, independent jaw chuck
nelja, üldjuhul üksteisest sõltumatult liikuvat osa (pakki) sisaldav padrun ümmaguste erineva ristlõikega toorikute kinnitamiseks tööpinki (vrd kolmepakiline padrun), a chuck used in a lathe or in certain other types of machine tools, comprising four jaws disposed at right angles to each other and acting usually independetly of each other (compare: three-jaw chuck)