Oil filter for purifying lubricating oil

Claim 1

Oil filter for the cleaning of lubricating oil, in particular for internal combustion engines of motor vehicles, with a filter housing with a cap connectable with the latter by screwing, said housing being arranged at least approximately upright in the installed condition, and with a ring-shaped filter insert detachably connectable with said cap, which filter insert, at the end disposed opposite the cap, is tightly seated radially on the inside in a sliding seat on a nipple rigidly joined with the housing, whereby in the filter housing, provision is made for an oil inlet for contaminated oil to the feed-to space surrounding the filter insert, and for an oil outlet for cleaned oil from the flow-off space formed by the interior space of the filter insert, and whereby, furthermore, provision is made in the lower zone of the filter housing for a discharge duct connected with an oil-collecting space for oil remaining in the filter housing when the filter insert is changed, said discharge duct being automatically opened by a valve-like acting member with each change of the filter insert, but is constantly closed off as for the rest, characterized in that a center bar (3) is connected with the cap (2) with limited axial displaceability, said bar, in its zone close to the cap, having a piston-like thickening (6) resting radially tightly against the falter insert (14) in a sliding seat, against which thickening the filter insert (14) rests radially tightly in a sliding seat, said thickening separating the flow-to space (7) from the flow-off space (8) and having in its lower end zone a valve-like acting member cooperating with the discharge duct (11).