Convertible gas spring

A gas spring system comprising

• (a) at least two gas springs each having a rod which can be moved to compress a gas therein,
• (b) each said gas spring having a cylinder defining at least in part a gas chamber, a piston rod slidably received in said cylinder, movable between extended and retracted positions, and constructed and arranged to compress a gas within said chamber when moving from its extended position toward its retracted position, a valve cavity within said cylinder having an entrance opening to the exterior of said cylinder and an end spaced from said entrance, said cavity being constructed and arranged to receive therein either one of a first valve assembly and a second valve assembly, port means in said cylinder communicating said cavity with said chamber, all of said port means communicating said cavity with said chamber through said end of said cavity and said cavity communicating with said chamber only through said port means, a bleed passage in said cylinder communicating with said cavity for bleeding off gas under pressure in said chamber through said cavity and bleed passage, said bleed passage opening into said cavity and being spaced from and not opening directly into said chamber, said first valve assembly having a body constructed and arranged to be received in said cavity with a passage therethrough constructed and arranged to communicate with all of said port means and said entrance when said body is received in said cavity, a first valve carried by said first body and constructed and arranged to control the flow of gas through said passage through said first body, said first valve being normally closed and opening in response to gas supplied to the said cavity upstream of said first valve at a pressure substantially greater than the pressure of gas in said chamber and when such upstream pressure is relieved closes to retain gas under pressure in said chamber, a first gasket associated with said first body and constructed and arranged to provide in a first position a seal between said first body and said cavity while simultaneously permitting all of said port means to communicate with said passage in said first body and preventing all of said port means from communicating with said bleed passage and in a second position enabling said port means to communicate with said bleed passage, and releasable means associated with said first body and constructed and arranged to releasably retain said first body in said cavity with said first gasket in such first position and to enable movement of said first gasket to such second position without releasing said first body from said cavity, and said second valve assembly has a second body constructed and arranged to be slidably received in said cavity for movement between first and second spaced apart positions therein and having a passage therethrough constructed and arranged to communicate with all of said port means and said entrance when said second body is received in said cavity, a second valve carried by said second body and constructed and arranged to control the flow of gas through said passage through said second body, said second valve being normally closed and opening in response to gas supplied to said cavity upstream of said first valve at a pressure substantially greater than the pressure of the gas in said chamber and closing when the chamber gas pressure approaches such upstream gas pressure, a second gasket associated with said second body and constructed and arranged to provide in such first position of said second body a seal between said second body and said cavity while both permitting all of said port means to communicate with said passage in said second body and preventing all of said port means from communicating with said bleed passage and in such second position of said second body enables said port means to communicate with said bleed passage, said second body having generally opposed first and second effective areas, said first effective area communicating with said cavity upstream of said second valve and said second effective area communicating with said port means downstream of said second valve, said second effective area being smaller than said first effective area and constructed and arranged so that when gas under pressure is applied to said cavity upstream of said second valve and said second body is in its first position, said second body is moved to its second position only when the pressure of the gas in said chamber is substantially greater than such gas pressure upstream of said second valve and acting on such first effective area, and removable retainer means constructed and arranged to removably retain said second body in said cavity while permitting said second body to move between said first and second positions thereof,
• (c) said second valve assembly being received in said cavity of each of said gas springs, and
• (d) a modular control device for supplying gas under pressure to said gas springs comprising a pair of end plates, a supply port in one of said end plates, a gauge port in one of said end plates, a pressure gauge connected to said gauge port, a bleed port in one of said end plates, a bleed valve connected to said bleed port, at least two module blocks received between said end plates and disposed in generally opposed face to face relationship to each other, a supply passage through each of said module blocks and communicating with said inlet port, a gauge and bleed passage through each of said module blocks and communicating with both said gauge ports and said bleed port, an outlet in each of said module blocks constructed and arranged for connection to at least one of said gas springs, a first control valve in each of said module blocks constructed and arranged to selectively connect and disconnect said supply passage with said outlet of its associated block, and a second control valve in each of said module blocks constructed and arranged to selectively connect and disconnect said gauge and bleed passage with said outlet of its associated module block, whereby the first and second control valves of each module block can be manipulated to control the supplying of gas under pressure to a gas spring connected to the outlet thereof, to determine the pressure of gas supplied to such spring, and to bleed to a low pressure point such as the atmosphere gas in a feed line to such gas spring connected to such outlet of such block

For a gas spring having a cylinder defining at least in part a gas chamber, a piston rod slidably received in said cylinder, movable between extended and retracted positions and constructed and arranged to compress a gas within such chamber when moving from its extended position toward its retracted position, a valve cavity within said cylinder having an entrance opening to the exterior of said cylinder and an end spaced from said entrance, said cavity being constructed and arranged to interchangeably receive therein either one of a first valve assembly or a second valve assembly, a port in said cylinder communicating said cavity with said chamber through said end of said cavity and said cavity communicating with said chamber only through said port, and a bleed passage in said cylinder and communicating with said cavity for bleeding off gas under pressure in said chamber through said cavity and bleed passage, said bleed passage opening into said cavity and being spaced from and not opening directly into said chamber;

• a first valve assembly and a second valve assembly, said first valve assembly comprising a body constructed and arranged to be received in said cavity with a passage therethrough constructed and arranged to communicate with said port and said entrance when said body is received in said cavity, a first valve carried by said first body and constructed and arranged to control the flow of gas through said passage through said first body, said first valve being normally closed and opening in response to gas supplied to the said cavity upstream of said first valve at a pressure substantially greater than the pressure of gas in said chamber and when such upstream pressure is relieved closes to retain gas under pressure in said chamber, a first gasket carried by said first body and constructed and arranged to provide in a first position a seal between said first body and said cavity while simultaneously permitting said port to communicate with said passage in said first body and preventing said port from communicating with said bleed passage and in a second position enabling said port to communicate with said bleed passage, and releasable means on said first body and constructed and arranged to releasably retain said first body in said cavity with said first gasket in such first position and to enable movement of said first gasket to such second position without releasing said first body from said cavity;
• and said second valve assembly comprising a second body constructed and arranged to be slidably received in said cavity for movement between first and second spaced apart positions therein and having a passage therethrough constructed and arranged to communicate with said port and said entrance when said second body is received in said cavity, a second valve carried by said second body and constructed and arranged to control the flow of gas through said passage through said second body, said second valve being normally closed and opening in response to gas supplied to said cavity upstream of said first valve at a pressure substantially greater than the pressure of the gas in said chamber and closes when the chamber gas pressure approaches such upstream gas pressure, a second gasket associated with said second body and constructed and arranged to provide in such first position of said second body a seal between said second body and said cavity while simultaneously permitting said port to communicate with said passage in said second body and preventing said port from communicating with said bleed passage, and in such second position of said second body enabling said port to communicate with said bleed passage, said second body having generally opposed first and second effective areas, said first effective area constructed and arranged to communicate with said cavity upstream of said second valve and said second effective area constructed and arranged to communicate with said port downstream of said second valve, and said second effective area being smaller than said first effective area and constructed a and arranged so that when gas under pressure is applied to said cavity upstream of said second valve and said second body is in its first position, said second body is moved to its second position only when the pressure of the gas in said chamber is substantially greater than such pressure of such gas upstream of said second valve and acting on such first effective area, whereby when said first valve assembly and releasable means are received in said cavity the gas spring can be utilized as a self-contained unit and, when said second valve assembly is received in said cavity such gas spring can be utilized with an external source of gas under pressure.