Abstract: A multi-tube hydraulic cylinder includes annular seal assemblies joining adjacent tubes. Each assembly includes an annular primary seal member and an annular base seal member. The primary seal member is formed from relatively soft elastomer and includes inner and outer seal ribs which engage the bottom of a seal groove and the surface of an adjacent tube. The primary seal member is mounted on the base seal member, is formed from an elastomer harder than the material in the primary seal member, and includes inner and outer seal ribs and a heel facing outwardly of the seal groove on the end of the base member away from the seal ribs. The base member has an axial length greater than its radial thickness. When the seal assembly is compressed between the two tubes the seal ribs of the two members provide low pressure and high pressure seals for confining hydraulic fluid in the chamber.

Abstract: A multi-tube hydraulic cylinder includes annular seal assemblies joining adjacent tubes. Each assembly includes an annular primary seal member and an annular base seal member. The primary seal member is formed from relatively soft elastomer and includes inner and outer seal ribs which engage the bottom of a seal groove and the surface of an adjacent tube. The primary seal member is mounted on the base seal member, is formed from an elastomer harder than the material in the primary seal member, and includes inner and outer seal ribs and a heel facing outwardly of the seal groove on the end of the base member away from the seal ribs. The base member has an axial length greater than its radial thickness. When the seal assembly is compressed between the two tubes the seal ribs of the two members provide low pressure and high pressure seals for confining hydraulic fluid in the chamber.