Filter cartridge end cap assembly and method of manufacture

Claim 1

An end cap assembly for a filter cartridge 10 including a tubular filter element 22 comprising: an end cap 14 having an inner surface , an outer surface 30, an outer circumference 28 connecting said inner and said outer 30 surfaces and having dimensions such that the inner surface of said filter element 22 may be drawn over said circumference 28 and a projection 36 adjacent said circumference 28 and extending beyond said outer surface 30; a lock ring 18 having an inner surface, an outer surface 34, an inner circumferential 32 surface connecting said inner and said outer 34 surfaces and sized to capture said filter element 22 between said lock ring inner circumferential surface 32 and said end cap outer circumference 28 and a projection 38 adjacent said lock ring inner circumferential surface 32 and extending beyond said lock ring outer surface 34 a distance substantially equal to the extension of said end cap projection 36 so that, when said end cap 14 and said lock ring 18 are assembled to capture said filter element 22, and with said end cap outer surface 30 and said lock ring outer surface 34 aligned, said end cap projection 36 and said lock ring projection 38 extend substantially equally from said end cap and said lock ring outer surfaces 30, 34; said projections 36,38 being supplied so that heat may be applied to said projections 36,38 after assembly of said lock ring 18 to said end cap 14 to fuse said lock ring 18 to said end cap 14 to provide a leak-proof seal therebetween.