Sealing for machine elements which move back and forth

In a sealing for back and forth moving machine elements, particularly for the sealing of axially back and forth moving piston rods for hydraulic cylinders, with a seal which seals against a housing as well as against the axially back and forth moving piston rod, an additional sealing protection element arranged between the seal and the oil pressure chamber of the cylinder, and a stripper turned toward the atmosphere, the improvement wherein

• the additional sealing protection element comprises a preceding protection element formed with a lip, said lip being directed toward said oil pressure chamber,
• the seal constitutes a lip seal, the latter in cooperation with and between the piston rod, the housing and said preceding protection element define another oil chamber,
• said back and forth moving piston rod and said housing constitute relatively moveable elements,
• said lip of said preceding protection element contacts one of said relatively moveable elements and is formed with openings, said openings form a connection between said pressure oil chamber and said another oil chamber between said preceding protection element and said lip seal.