Rolling diaphragm seal between two relatively moving parts

In an apparatus including a cylinder element, a piston element reciprocally movable in the cylinder, a rod extending axially from the piston with an annular space defined between said rod and cylinder element, and a rolling diaphragm seal and means for securing same between said rod and cylinder element for separating said annular space into two portions, the improvement in combination therewith wherein, said rod comprises a first part of first diameter, and an axially adjacent second part of second larger diameter, with a shoulder defined at the transitional area between said first and second parts and an annular groove extending lengthwise generally axially inward from the surface of said shoulder the groove having radial width defined by an inner diameter and an outer diameter, the inner diameter being substantially the same as said first diameter, the seal being a tubular member formed by a tubular wall with first and second ends, and having wall thickness along its length and greater thickness at the first end, said groove width being approximately the same as the thickness of said seal's first end, said first end being removably located in said groove and said second end being secured to said cylinder, said apparatus further comprising an annular member of elastic material and movable between a first position on said rod and a second position, the first position of said annular member being spaced from said shoulder and thus defining therebetween a gap of smaller length than the thickness of said first end of the seal for locking said first end in said groove, said second position of the member being spaced axially farther from the first position and from said first end of the seal to permit removal of said first end from the groove.