Gas spring

Claim 1

A method of assembling a gas spring, said gas spring comprising a cylinder member (1) having an axis and defining a cavity therein, and further comprising a piston rod (3) axially extending through at least one end of said cylinder member (1), said piston rod member (3) extending through a piston rod guiding and sealing group (5, 4, 7, 8, 9, 10) adjacent to said at least one end of said cylinder member (1), said piston rod guiding and sealing group (5, 4, 8, 8, 9, 10) including two axially spaced sealing arrangements (4, 5, 7; 9, 10), namely an axially outer sealing arrangement (9, 10) and an axially inner sealing arrangement (4, 5, 7) axially fixed with respect to said cylinder member (2), said sealing arrangements (, 20; 4, 5, 7) being in sliding contact with an external surface of said piston rod member (3), a lubricant chamber (11) being provided axially between said two sealing arrangements (9, 10; 4, 5, 7) adjacent to said external surface of said piston rod member (3), said lubricant chamber (11) containing a lubricant agent, a working chamber (2) being provided within said cavity adjacent to said axially inner sealing arrangement (4, 5, 7), said working chamber (2) containing a volume of pressurized gas, said axially inner sealing arrangement (4, 5, 7) being a pressure-resistant sealing arrangement capable of maintaining the pressure of said volume of pressurized gas at a level exceeding the pressure within said lubricant chamber (11), said piston rod member (3) being connected with a piston unit (20) inside said cavity, said method comprising the following steps: (a) inserting said piston rod member (3) with said piston unit (20) into said cavity; (b) inserting said axially inner sealing arrangement (4, 5, 7) into said cavity and axially fixing said axially inner sealing arrangement (4, 5, 7) with respect to the said cylinder member (1) against axial movement thereof by inserting a support sleeve (8) along the inner wall surface of said cylinder member (1) and providing abutment means (12) adjacent the axially outer end of said cylinder member (1) abutting against the axially outer end of said support sleeve (8), said abutment means (12) being free of overlapping with the inner cross-sectional area of said support sleeve (8); (c) introducing a gas into said working chamber (2) across said axially inner sealing arrangement (4, 5, 7) such as to provide said volume of pressurized gas within said working chamber (2); (d) introducing said lubricant agent into said lubricant chamber (11); (e) closing said lubricant chamber (11) by said axially outer sealing arrangement (9, 10) by inserting a sealing member (9) into said support sleeve (8) and thereupon inserting an annular closure member (10) into said support sleeve (8), such that said sealing member (9) is free of axial abutment against said support sleeve (8) in the axial inward direction and is supported in the axial outward direction by said closure member (10).

Claim 2

A method of assembling a gas spring, said gas spring comprising a cylinder member (1) having an axis and defining a cavity therein, and further comprising a piston rod (3) axially extending through at least one end of said cylinder member (1), said piston rod member (3) extending through a piston rod guiding and sealing group (5, 4, 7, 8, 9, 10) adjacent to said at least one end of said cylinder member (1), said piston rod guiding and sealing group (5, 4, 8, 8, 9, 10) including two axially spaced sealing arrangements (4, 5, 7; 9, 10), namely an axially outer sealing arrangement (9, 10) and an axially inner sealing arrangement (4, 5, 7) axially fixed with respect to said cylinder member (2), said sealing arrangements (, 20; 4, 5, 7) being in sliding contact with an external surface of said piston rod member (3), a lubricant chamber (11) being provided axially between said two sealing arrangements (9, 10; 4, 5, 7) adjacent to said external surface of said piston rod member (3), said lubricant chamber (11) containing a lubricant agent, a working chamber (2) being provided within said cavity adjacent to said axially inner sealing arrangement (4, 5, 7), said working chamber (2) containing a volume of pressurized gas, said axially inner sealing arrangement (4, 5, 7) being a pressure-resistant sealing arrangement capable of maintaining the pressure of said volume of pressurized gas at a level exceeding the pressure within said lubricant chamber (11), said piston rod member (3) being connected with a piston unit (20) inside said cavity, said method comprising the following steps: (a) inserting said piston rod member (3) with said piston unit (20) into said cavity; (b) inserting said axially inner sealing arrangement (4, 5, 7) into said cavity and axially fixing said axially inner sealing arrangement (4, 5, 7) with respect to the said cylinder member (1) against axial movement thereof by inserting a support sleeve (8) along the inner wall surface of said cylinder member (1) and providing abutment means (12) adjacent the axially outer end of said cylinder member (1) abutting against the axially outer end of said support sleeve (8), said abutment means (12) being free of overlapping with the inner cross-sectional area of said support sleeve (8); (c) introducing a gas into said working chamber (2) across said axially inner sealing arrangement (4, 5, 7) such as to provide said volume of pressurized gas within said working chamber (2); (d) introducing said lubricant agent into said lubricant chamber (11); (e) closing said lubricant chamber (11) by said axially outer sealing arrangement (9, 10) by inserting a sealing member (9) into said support sleeve (8) and thereupon inserting an annular closure member (10) into said support sleeve (8), such that said sealing member (9) is free of axial abutment against said support sleeve (8) in the axial inward direction and is supported in the axial outward direction by said closure member (10).