Convertible gas spring

Claim 2

A combination comprising a gas spring having a rod which can be moved to compress a gas therein comprising, 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 and 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 first valve assembly and a second valve assembly, one of said first valve assembly and said second valve assembly being received in said cavity, 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 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, 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 with generally opposed ends, said 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 second 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 which both permits all of said port means to communicate with said passage in said second body and prevents 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 communication 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 pressure of such gas upstream of said second valve and acting on such first effective area, and removable retainer means constructed and arranged to retain said second body in said cavity while permitting said second body to move between said first and second positions thereof, 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 and retainer means are received in said cavity such as gas spring can be utilized with an external source of gas under pressure.

Claim 3

The gas spring of claim 1 which also comprises a second gasket carried by said first body and constructed and arranged to provide a seal between said first body and said cavity downstream of said bleed passage.

Claim 4

The gas spring of claim 1 which also comprises a second gasket carried by said second body and constructed and arranged to provide a seal between said second body and said cavity downstream of said bleed passage.

Claim 5

The gas spring of claim 1 wherein said cavity has a threaded portion adjacent said entrance thereof and said releasable means comprises a mating threaded portion on said first body.

Claim 6

The gas spring of claim 1 which also comprises a recess in said first body constructed and arranged to receive a tool for removing said first body from said cavity, and a stem normally disposed in part in said recess and operably connected to said first valve to open said first valve when said stem is depressed by the tool being inserted in said recess, whereby inserting a tool in said recess depresses said stem to open said first valve and thereby bleed any gas under pressure in said chamber to the atmosphere through said passage in said first body and said entrance of said cavity.

Claim 7

The gas spring of claim 5 wherein said cavity also comprises a threaded portion adjacent said entrance and said releasable means comprises a mating threaded portion on said first body.

Claim 8

The gas spring of claim 1 which also comprises an annular groove in an end of said first body and encircling both said passage therethrough and all of port means, said groove having a base and a pair of spaced apart and generally upstanding side walls with the side wall adjacent said passage being inclined at an acute included angle to said base of said groove, and said first gasket being circumferentially continuous, received in said groove and having a base and upstanding side walls complementary to said base and upstanding side walls of said groove, whereby the said first gasket is at least in part retained in said groove by said side wall being inclined at an acute included angle to the base of said groove.

Claim 9

The gas spring of claim 7 wherein said first gasket is also secured in said groove in said first body by an adhesive.

Claim 10

The gas spring of claim 1 which also comprises an annular groove in an end of said second body and encircling both said passage therethrough and said port, said groove having a base and a pair of spaced apart and generally upstanding side walls with the side wall adjacent said passage being inclined at an acute included angle to said base of said groove, and said second gasket being circumferentially continuous, received in said groove and having a base and upstanding side walls complementary to said base and upstanding side walls of said groove, whereby said second gasket is at least in part retained in said groove by said side wall being inclined at an acute included angle to the base of said groove.

Claim 11

The gas spring of claim 9 wherein said second gasket is also secured in said groove in said second body by an adhesive.

Claim 12

The gas spring of claim 1 wherein said first valve is disposed in said passage through said first body and comprises a poppet valve having a stem slidably received in a housing and connected to a valve head movable to open and close said first valve, and said first body has a positive stop disposed under said valve head to limit the extent of travel of said stem when said poppet valve opens so tht said stem does not strike said housing, whereby damage of the said poppet valve is avoided.

Claim 13

The gas spring of claim 11 wherein said poppet valve is a conventional core valve.

Claim 14

The gas spring of claim 1 wherein said second valve is disposed in said passage through said second body and comprises a poppet valve having a stem slidably received in a housing and connected to a valve head movable to open and close said second valve, and said second body has a positive stop disposed under said valve head to limit the extent of travel of said stem when said poppet valve opens so that said stem does not strike said housing, whereby damage of said poppet valve is avoided.

Claim 15

The gas spring of claim 13 wherein said poppet valve is a core valve.

Claim 16

The gas spring of claim 1 wherein said cavity also comprises a threaded portion adjacent said entrance and said removable retainer means comprises a nipple having threads mating with said threaded portion of said cavity, a stop surface constructed and arranged to bear on said second body when said second body is in its second position and to be spaced therefrom when said second body is in its first position, and a gas passage through said nipple.

Claim 17

The gas spring of claim 15 wherein said nipple is constructed and arranged for connecting a feed line to said cavity.

Claim 18

The gas spring of claim 16 which also comprises an annular gasket carried by said nipple and constructed and arranged to provide a seal between said nipple and said cavity when said nipple is secured in said cavity.

Claim 19

The gas spring of claim 1 wherein said bleed passage also communicates with said valve cavity downstream of its entrance and upstream of said first and second valve assemblies when received therein, and also comprises a third valve in said gas spring, operable connected to said bleed passage and which closes to prevent gas from said entrance flowing through said bleed passage to said chamber and opens to permit gas from said chamber to flow through said bleed passage to said entrance.

Claim 20

The gas spring of claim 18 wherein said third valve comprises a check valve which when closed has a first effective area exposable to gas under pressure from said chamber which is in the range of 1/4 to 3/4 of a second effective area generally opposed to said first effective area and exposable to gas under pressure in said entrance of said valve cavity.

Claim 21

The gas spring of claim 19 wherein the ratio of said first effective area to said second effective area of said check valve is less than the ratio of said first effective area to said second effective area of said second valve.

Claim 22

The gas spring of claim 1 which also comprises a second valve cavity in said cylinder, having an entrance opening to the exterior of said cylinder, and constructed and arranged to removably receive a bleed valve assembly therein, said bleed passage communicating with said first valve cavity downstream of its entrance and upstream of said first and second valve assemblies when received therein, a bleed valve assembly removably received and releasably retained in said second valve cavity and having a third valve operable connected to said bleed passage and which closes to prevent gas from said entrance flowing through said bleed passage to said chamber and opens to permit gas from said chamber to flow through said bleed passage to said entrance, a second port communicating with said gas chamber and said second valve cavity, and a fourth valve carried by said bleed valve assembly which closes to prevent gas under pressure in said chamber from flowing out of said chamber through said second port when said bleed valve assembly is fully received and retained in said second cavity and opens to permit gas under pressure in said chamber to flow out of said chamber through said second passage and bleed into said first valve cavity downstream of its entrance and upstream of said first and second valve assemblies when received therein and after removal of said bleed valve assembly from said second cavity begins and before it is completely disengaged from said cylinder for removal from said second valve cavity.

Claim 23

The gas spring of claim 21 wherein when said fourth valve opens the gas under pressure in said cylinder bleeds through said third valve.

Claim 24

The gas spring of claim 1 wherein said valve cavity has a generally cylindrical sidewall, said body of said first valve assembly is generally cylindrical and has a pair of generally opposed ends with said passage therethrough extending through both of said ends, said first gasket has an annular and circumferentially continuous ring carried by said body adjacent one end thereof which encircles both such opening of said passage of said first body at one end thereof, and the opening of all of said port means through said end of said cavity, and bears on said end of said cavity when said first body is in said first position in said cavity.

Claim 25

The gas spring of claim 23 which also comprises a circumferentially continuous groove in said first body between said opposed ends thereof and downstream of said bleed passage, and a circumferentially continuous ring of an elastomeric material received in said groove and constructed and arranged to provide seal between said first body and said cavity downstream of said bleed passage when said first valve assembly in its first position in said cavity.

Claim 26

The gas spring of claim 23 which has only one said port communicating said cavity with said chamber.

Claim 27

The gas spring of claim 23 wherein said valve cavity has a generally cylindrical sidewall, said body of said second valve assembly is generally cylindrical and has a pair of generally opposed ends with said passage therethrough extending through both of said ends, said second gasket has an annular and circumferentially continuous ring carried by said body adjacent one end thereof which encircles both such opening of said passage of said second body through such one end thereof and the opening of all of said port means through said end of said cavity, and bears on said end of said cavity when said second body is in said first position in said cavity.

Claim 28

The gas spring of claim 26 which also comprises a circumferentially continuous groove in said second body between said opposed ends thereof and downstream of said bleed passage, a circumferentially continuous ring of an elastomeric material received in said groove and constructed and arranged to provide a seal between said second body and said cavity downstream of said bleed passage when said first valve assembly is in its second position in said cavity.

Claim 29

The gas spring of claim 26 which has only one said port communicating said cavity with said chamber.

Claim 30

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

Claim 31

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

Claim 32

The gas spring system of claim 20 wherein said bleed passage also communicates with said valve cavity downstream of its entrance and upstream of said first and second valve assemblies when received therein, and also comprises a third valve in said gas spring, operably connected to said bleed valve and which closes to prevent gas from said entrance flowing through said bleed passage to said chamber and opens to permit gas from said chamber to flow through said bleed passage to said entrance of said valve cavity.

Claim 33

The gas spring system of claim 30 wherein said third valve comprises a check valve which when closed has a first effective area exposable to gas under pressure from said chamber which is in the range of 1/4 to 3/4 of a second effective area generally opposed to said first effective area and exposble to gas under pressure in said entrance of said valve cavity.

Claim 34

The gas spring system of claim 31 wherein the ratio of said first effective area to said second effective area of said check valve is less than the ratio of said first effective area to said second effective area of said second valve.

Claim 35

The gas spring of claim 29 wherein said valve cavity has a generally cylindrical sidewall, and said body of said second valve assembly is generally cylindrical and has a pair of generally opposed ends with said passage therethrough extending through both of said ends, said second gasket has an annular and circumferentially continuous ring carried by such body adjacent one end thereof which encircles both such opening of said passage of said second body through such one end thereof and the opening of all of said port means through said end of said cavity, and bears on said end of said cavity when said second body is in said first position in said cavity.

Claim 36

The gas spring of claim 33 which also comprises a circumferentially continuous groove in said second body between said opposed ends thereof and downstream of said bleed passage, and a circumferentially continuous ring of an elastomeric material received in said groove and constructed and arranged to provide a seal between said second body and said cavity downstream of said bleed passage when said second valve assembly is in its second position in said cavity.

Claim 37

The gas spring of claim 24 which has only one said port communicating said cavity with said chamber.

Claim 38

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.

Claim 39

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.

Claim 40

The valve assemblies of claim 36 which also comprise a recess in said first body constructed and arranged to received a tool for removing said first body from such cavity, and a stem normally disposed in part in said recess and operably connected to said first valve to open said first valve when said stem is depressed by the tool being inserted in said recess, whereby inserting a tool in said recess depresses said stem to open said first valve and thereby bleed any gas under pressure in such chamber to the atmosphere through said passage in said first body and such entrance of such cavity.

Claim 41

The valve assemblies of claim 37 wherein said cavity has a threaded portion adjacent such entrance and said releasable means comprises a mating threaded portion of said first body.

Claim 42

The valve assemblies of claim 36 which also comprises an annular groove in an end of said first body and encircling both said passage therethrough and such port, said groove having a base and pair of spaced apart and generally upstanding side walls with the side wall adjacent said passage being inclined at an acute included angle to said base of said groove, and said first gasket being circumferentially continuous, received in said groove and having a base and upstanding side walls complementary to said base and upstanding side walls of said groove, whereby said first gasket is at least in part retained in said groove by said side wall being inclined at an acute included angle to the base of said groove.

Claim 43

The valve assemblies of claim 36 which also comprises an annular groove in an end of said second body and encircling both said passage therethrough and such port, said groove having a base and pair of spaced apart and generally upstanding side walls with the side wall adjacent said passage being inclined at an acute included angle to said base of said groove, and said second gasket being circumferentially continuous, received in said groove and having a base and upstanding side walls complementary to said base and upstanding side walls of said groove, whereby said second gasket is at least in part retained in said groove by said side wall being inclined at an acute included angle to the base of said groove.

Claim 44

The valve assemblies of claim 36 wherein said first valve is disposed in said passage through said first body and comprises a poppet valve having a stem slidably received in a housing and connected to a valve head movable to open and close said first valve, and said first body has a positive stop disposed under said valve head to limit the extent of travel of said stem when said poppet valve opens so that said stem does not strike said housing, whereby damage of said poppet valve is avoided.

Claim 45

The valve assemblies of claim 36 wherein said second valve is diposed in said passage through said second body and comprises a poppet valve having a stem slidably received in a housing and connected to a valve head movable to open and close said second valve, and said second body has a positive stop disposed under said head to limit the extent of travel of said stem when said poppet valve opens so that said stem does not strike said housing, whereby damage of said poppet valve is avoided.