the filter doesnt NEED to seal at the top...oil is filtered from the inside OUT
(or is it vise versa).
heres some details on the pat. numbers and my findings from jan. 2005
at the time MANY thought the patent numbers stamped on the filter
bottoms were specific to the construction and TYPE of filter...and
therefor many were seeking any filter w/ the pat. numbers stamped
on 'em (which also said made in germany).
in reality the patent numbers and the "made in germany" were specific
only to the plastic top, bottom (w/ felt seal) and the filter housing design.
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upon review of the patent numbers it seem
the FILTER patents only cover PORTIONS of the filter not
necessarily the manufacturing of the filter itself or material
(let alone the number of pleats) being used by any given
filter manufacture.
the patents cover the base/seal & the locking top/filter houseing,
NOT the filter itself.
Heres information provided from the US PATENT & TRADE MARK
office (I've provided LINKS to the patent documents you
can see engineering drawings for each patent at these links)
Patents Numbers 6,086,763 and 6,554.139 are the only Patent
numbers stamped on the filters.
6,086,763 covers the SEALING/compression ring on the filter bottom
and the DISK/base design...this patent has a GERMAN origin/inventors
and is assigned to Ing. Walter Hengst GmbH & Co. (Munster, DE)
6,554,139 covers the extension & locking portion of the filter, this
patent has origins/inventors based in California & is
assiged to Parker-Hannifin Corporation (Cleveland, OH)
6,554,139 appears (by the engineering drawings) to cover the filter
housing, cap & filter top/locking portion....i laughed when i
read the part about the "dripless" element/housing...
so the mystery continues...possibly only the BASE of the filter and
its sealing ring are made in germany...