Gas spring with tubular shell seal

In a gas spring having a cylinder open at one end and closed at the other end, a piston slidable in said cylinder, a rod fixed to said piston and projecting out of said cylinder through the open end thereof, and a body of oil and a gas under pressure in said cylinder, the combination of, a rigid annulus disposed in said cylinder adjacent said open end thereof and encircling said rod, a tubular shell located between said closed end and said rigid annulus and having an outer generally annular end portion abutting said annulus and an inner end portion surrounding said rod with a generally cylindrical wall connecting said outer and inner end portions, said shell being made of a flexible and resilient material, a first annular portion formed on said outer end portion of said shell adjacent said rod and extending around the entire inner periphery of said outer end portion, said first annular portion resiliently engaging said rod around the entire circumference thereof to form a seal between the shell and the rod, and a second annular portion formed on said outer end portion at the exterior of said shell around the entire outer periphery of said outer end portion and engaging the inside of said cylinder around the entire circumference thereof to form a seal between the shell and the cylinder whereby said shell seals the open end of the cylinder, said inner end portion of said shell normally resiliently engaging said rod around the periphery thereof and said wall of said shell being spaced from said rod whereby the shell and the rod define an annular cavity, said cavity being filled with at least a portion of said body of oil, said outer and inner end portions having a thickness greater than the thickness of said wall whereby said wall expands and contracts in response to differences of the pressures in said cylinder and in said cavity as said piston slides back and forth in the cylinder thereby to pump oil into and out of said cavity between said inner end portion and said rod and maintain the cavity full of oil.

In a gas spring having a cylinder open at one end and closed at the other end, a piston slidable in said cylinder, a rod fixed to said piston and projecting out of said cylinder through the open end thereof, and a body of oil and a gas under pressure in said cylinder, the combination of, a rigid annulus disposed in said cylinder adjacent said open end thereof and encircling said rod, a tubular shell located between said closed end and said rigid annulus and having an outer generally annular end portion abutting said annulus and and inner end surrounding said rod with a generally cylindrical wall connecting said outer end portion and inner end, said shell being made of a flexible and resilient material, a first annular portion formed on said outer end portion of said shell adjacent said rod and extending around the entire inner periphery of said outer end portion, said first annular portion resiliently engaging said rod around the entire circumference thereof to form a seal between the shell and the rod, and a second annular portion formed on the exterior of said shell around the entire outer periphery of said outer end portion and engaging the inside of said cylinder around the entire circumference thereof to form a seal between the shell and the cylinder whereby said shell seals the open end of the cylinder, said inner end of said shell normally resiliently engaging said rod around the periphery thereof and said wall of said shell being spaced from said rod whereby the shell and the rod define an annular cavity, said cavity being filled with at least a portion of said body of oil, said wall expanding and contracting in response to differences of the pressures in said cylinder and in said cavity as said piston slides back and forth in the cylinder thereby to pump oil into and out of said cavity between said inner end and said rod and maintain the cavity full of oil, and means coacting between said piston, said rod and said shell to move the inner end of said shell away from said rod and permit oil to flow from said cylinder into said cavity.

In a gas spring having a cylinder open at one end and closed at the other end, a piston slidable in said cylinder, a rod fixed to said piston and projecting out of said cylinder through the open end thereof, and a body of oil and a gas under pressure in said cylinder, the combination of, a rigid annulus disposed in said cylinder adjacent said open end thereof and encircling said rod, a tubular shell located between said closed end and said rigid annulus and having an outer generally annular end portion abutting said annulus and inner end surrouding said rod with a generally cylindrical wall connecting said outer end portion and inner end, said shell being made of a flexible and resilient material, a first annular portion formed on said outer end portion of said shell adjacent said rod and extending around the entire inner periphery of said outer end portion, said first annular portion resiliently engaging said rod around the entire circumference thereof to form a seal between the shell and the rod, and a second annular portion formed on the exterior of said shell around the entire outer periphery of said outer end portion and engaging the inside of said cylinder around the entire circumference thereof to form a seal between the shell and the cylinder whereby said shell seals the open end of the cylinder, said inner end of said shell normally resiliently engaging said rod around the periphery thereof and said wall of said shell being spaced from said rod whereby the shell and the rod define an annular cavity, said cavity being filled with at least a portion of said body of oil, said wall expanding and contracting in response to differences of the pressures in said cylinder and in said cavity as said piston slides back and forth in the cylinder thereby to pump oil into and out of said cavity between said inner end and said rod and maintain the cavity full of oil, said shell being formed by first and second parts, said first part comprising said first and second annular portions and said end portion and said second part comprising said wall, and means selectively connecting said first and second parts of said shell.