Patent ID: 7282145

Claim:
An oil filter for a construction machine, comprising: a cylindrical casing provided with an oil inlet and an oil outlet; a removable lid provided on the casing; an oil filter element housed in the casing, the oil filter element being formed of two or more hollow element pieces piled on top of one another vertically; and a plurality of ring shaped connecting parts for detachably connecting adjacent ones of the element pieces to each other, the connecting parts each comprising one of engaging male and female screw parts comprising threads and provided on each of said adjacent element pieces, wherein inside and outside diameters of the ring shaped connecting parts are substantially equal to the inside and outside diameters of the element pieces such that the connecting pieces do not protrude to the inside or outside of the element pieces when the element pieces are joined by screw joining of the connecting parts, wherein the oil inlet is disposed at an upper side of a top one of the element pieces and the oil outlet is disposed at a bottom side of the casing in such a manner that a bottom one of the element pieces covers the oil outlet, whereby oil flows from the oil inlet to the oil outlet.