Packing assemblies

Claim 2

A fluid packing assembly of the kind comprising a sealing member mountable in a groove defined in one of a pair of relatively movable members between which it is required to establish a fluid seal, a sealing lip defined on said sealing member for engagement with the surface of said other of the pair of relatively movable members, a roughened zone formed on said sealing member adjacent said sealing lip, said roughened zone acting to disturb the fluid film on said surface in advance of the contact of the surface with the sealing lip.

Claim 3

A fluid packing assembly as claimed in claim 1 in which said roughened zone is positioned on the side of the sealing lip which in use, is exposed to the higher fluid pressure.

Claim 4

A fluid packing assembly as claimed in claim 2 in which the portion of the seal member which carries the roughened zone is flared outwardly from the portion of the seal member which carries the sealing lip whereby in use, the roughened zone will be pressed firmly into engagement with said surface.

Claim 5

A fluid packing assembly as claimed in claim 3 in which the roughened zone is provided with ribs.

Claim 6

A piston cylinder combination comprising a housing, an end closure for the housing and having an aperture therein, a piston rod extending through the aperture, an annular recess defined in the end closure about the piston rod, a packing assembly mounted in the recess, said packing assembly including an annular sealing member, annular sealing lips defined on the inner and outer sides of said sealing member, the sealing lips on the outer side of said sealing member engaging the adjacent wall of the recess and the sealing lips on the inner side of the sealing member engaging with the surface of the piston rod to provide a fluid seal therebetween, and an annular roughened zone defined on the inner side of the sealing member, said roughened zone being positioned at the end of the sealing member which in use is subjected to fluid pressure, said roughened zone acting to disturb the fluid film on the surface of the piston rod.

Claim 7

A piston cylinder combination comprising a housing, an end closure for the housing and having an aperture therein, a piston rod extending through the aperture, an annular recess defined in the end closure about the piston rod, a packing assembly mounted in the recess, said packing assembly including an annular sealing member, annular sealing lips defined on the inner and outer sides of said sealing member, the sealing lips on the outer side of said sealing member engaging the adjacent wall of the recess and the sealing lips on the inner side of the sealing member engaging with the surface of the piston rod to provide a fluid seal therebetween, and an annular roughened zone defined on the inner side of the sealing member, said roughened zone being positioned at the end of the sealing member which in use is subjected to fluid pressure, said roughened zone acting to disturb the fluid film on the surface of the piston rod.

Claim 8

A piston cylinder combination comprising first and second members defining annular cylindrical surfaces between whiCh it is desired to provide a fluid seal, one of said surfaces being defined by the base wall of an annular recess defined in one of said members, a packing assembly mounted in the recess, said packing assembly including an annular sealing member, annular sealing lips defined on the inner and outer sides of said sealing member, said lips co-operating with said surfaces to provide the fluid seal, and an annular roughened zone defined on the side of the sealing member presented to the surface of the other member, said roughened zone being positioned at the end of the sealing member which in use is subjected to fluid pressure, said roughened zone acting to disturb the fluid film on the surface of said other member.

Claim 9

A piston cylinder combination comprising first and second members defining annular cylindrical surfaces between whiCh it is desired to provide a fluid seal, one of said surfaces being defined by the base wall of an annular recess defined in one of said members, a packing assembly mounted in the recess, said packing assembly including an annular sealing member, annular sealing lips defined on the inner and outer sides of said sealing member, said lips co-operating with said surfaces to provide the fluid seal, and an annular roughened zone defined on the side of the sealing member presented to the surface of the other member, said roughened zone being positioned at the end of the sealing member which in use is subjected to fluid pressure, said roughened zone acting to disturb the fluid film on the surface of said other member.