Oil filter restriction sensor

Claim 1

An oil filter sensor device for insertion between the oil filter mounting bracket mounted on an internal combustion engine and an oil filter cartridge having a filter element therein, said sensor device providing a warning to an operator of said engine if a restricted oil filter condition occurs, said sensor device includes: a. a disk-shaped body means having a first generally flat surface and an opposite second generally flat surface; b. said body means having a first longitudinal passageway centrally positioned through said body means to carry filtered oil between the oil filter element and said engine bracket interconnecting through said first and second surfaces and a second longitudinal passageway separately formed in said body means to carry incoming unfiltered oil between said engine bracket and said oil filter cartridge and arranged to interconnect through said first and second surfaces; c. a closed internal cyclindrical bore formed in said body means having a first end opening through the outer surface of said body means, a slidable piston mounted within said cylindrical bore and sized to closely fit the diameter of said bore, a removable plug suitably mounted within the open end of said bore to close and seal the bore and to restrict the movement of said piston; d. a biasing means positioned within said bore between said plug and said piston to bias the piston in a first position away from said plug, said plug having an insulated electrical connector mounted therein which extends into said bore so that the piston when it moves to a second position against said biasing means makes electrical contact with said connector; e. a first internal passageway provided within said body means to interconnect said first longitudinal passageway with the bore nearest the plug and a second internal passageway within said body means interconnecting said second longitudinal passageway with the opposite end of said bore whereby the differential pressure across the oil filter will also be applied across said slidable piston so that when the differential pressure across the filter exceeds a predetermined amount indicating a restricted filter element the piston will be caused to slide to the second position in contact with said electrical connector; f. said electrical connector being connected to a suitable alarm circuit means for alerting the operator to the restricted oil filter condition; and g. a threaded mounting adapter arranged to be inserted through said first longitudinal passageway in said body means and threaded to said oil filter mounting bracket and the oil filter cartridge mounted on the opposite side of said body means.