Hydraulic cylinder with self-locking end cap

Claim 1

A hydraulic cylinder disposed on a longitudinal axis thereof comprising, an end cap having uninterrupted spiral threads formed internally thereon to extend in the direction of and about said longitudinal axis, means forming a work tool receiving aperture through a sidewall of said end cap, transversely of said longitudinal axis, and through a portion of said threads, and a generally circular patch of plastic material, having selflocking characteristics, bonded and confined to portions of said threads closely adjacent to said aperture to completely circumvent said aperture and a housing having said end cap threadedly mounted thereon, said plastic patch having a sufficient radial thickness relative to said longitudinal axis to be deformed by the threaded engagement between said end cap and said housing to resist relative turning movement therebetween and to seal the area whereat the thread portions of said housing intersect said aperture.