Abstract: A head end seal assembly for a hydraulic cylinder may include a cylinder seal carrier having a seal carrier bore with a main seal groove and a coating ring groove adjacent the main seal groove. A main seal disposed within the main seal groove is fabricated from a resilient material and engages a rod outer surface of a rod to substantially prevent leakage of pressurized fluid from the hydraulic cylinder. A coating ring disposed within the coating ring groove is fabricated from a thermoplastic polymer such as Teflon and engages the rod outer surface such that portions of the thermoplastic polymer are deposited into indentations on the rod outer surface as the rod slides past the coating ring to smooth the surface and reduce abrasion between the rod and the main seal. A second coating ring on the opposite side of the main seal may coat the rod as it moves in the opposite direction.

Abstract: A head end seal assembly for a hydraulic cylinder may include a cylinder seal carrier having a seal carrier bore with a main seal groove and a coating ring groove adjacent the main seal groove. A main seal disposed within the main seal groove is fabricated from a resilient material and engages a rod outer surface of a rod to substantially prevent leakage of pressurized fluid from the hydraulic cylinder. A coating ring disposed within the coating ring groove is fabricated from a thermoplastic polymer such as Teflon and engages the rod outer surface such that portions of the thermoplastic polymer are deposited into indentations on the rod outer surface as the rod slides past the coating ring to smooth the surface and reduce abrasion between the rod and the main seal. A second coating ring on the opposite side of the main seal may coat the rod as it moves in the opposite direction.

Abstract: An apparatus and method for coupling a piston to a rod to form a cylinder assembly are provided. The piston has a tapped bore extending therethrough for coupling to a first threaded region of the rod. The rod end extends beyond the piston member and includes a second threaded region for coupling to a tapped bore of a retaining member. The piston member is coupled to the rod member at a low torque, e.g., up to about 1000 Nm. An external thread of each of the threaded segment of the piston bore and the first threaded region of the first portion of the rod member may be formed with a root radius of greater than 0.125 pitch or with MJ class thread. The retaining member may include setscrews offset from one another for frictional engagement with the rod end. The thread pitch between the rod and the piston may be coarser than between the rod and the retaining member.