"United States Patent
`
`[19]
`
`[11]
`
`3,944,769
`
`Wagner
`[45] Mar. 16, 1976
`
`
`12/1967 Houser ............................ .. 200/83 B
`3/1973 Greenwood . . . . .
`. . . . . . . . . .. 200/83 R
`4/1973 Dijkema ....................... .. 73/393
`5/1973 Kermer . . . . . . .
`. . . . . . . . . .. 200/83 R
`6/1974 Wagner ...................... .. 280/150 AB
`
`
`
`3,359,388
`3,723,684
`3,728,899
`3,735,376
`3,818,764
`
`Primary Examiner——M. H. Wood, Jr.
`Assistant Examiner—-John P. Silverstrim
`Attorney, Agent, or Firm——Candor, Candor & Tassone
`
`[57]
`
`ABSTRACT
`
`A pressure sensing means having a housing provided
`with a chamber therein. A double wall fluid operated
`device is disposed in the chamber of the housing and
`is carried by the same, the walls of the device defining
`a chamber therebetween that is interconnected to the
`exterior of the housing by a passage. A charge of pres-
`sure fluid is sealed in the chamber of the housing to
`initially hold the walls of the device in flat abutting re-
`lation in a manner to prevent an adverse permanent 9
`set thereof. Subsequently, the chamber of the double
`wall fluid operated device is interconnected to the
`pressurized chamber of a container means for a vehic-
`ular air bag safety system whereby the pressure Sens-
`ing means can Subsequently detect loss or gain of pres-
`sure difierential across at least one of the walls of the
`double wall operated device for detection purposes or
`the like.
`
`3 Claims, 6 Drawing Figures
`
`[54] PRESSURE SENSING MEANS AND
`METHOD FOR MAKING A PRESSURIZED
`CONTAINER MEANS AND SYSTEM
`UTILIZING THE SAME
`
`[75]
`
`Inventor:
`
`[73]
`
`Assignee:
`
`Joseph P. Wagner, Knoxville, Tenn.
`
`Rohertshaw Controls Company,
`Richmond, Va.
`
`[22]
`
`[21]
`
`[63]
`
`(521
`
`[51]
`[58]
`
`[56]
`
`Filed:
`
`Sept. 25, 1974
`
`Appl. No.: 509,009
`
`Related U.S. Application Data
`Continuation of 'Ser. No. 321,648, Jan. 8, 1973,
`abandoned.
`
`U.S. Cl. ............. .. 200/83 A; 73/393; 200/83 B;
`200/83 N; 280/150 AB; 340/242
`Int. Cl.’ ....................................... .. 11011! 35/34
`Field of Search 280/150 AB; 200/83 J, 83 N,
`200/83 A, 83 B, 83 R, 61.25, 61.26;
`340/242; 73/393, 407 R
`
`References Cited
`UNITED STATES PATENTS
`
`,
`
`Siddal ............................. .. 200/83 N
`4/1928
`
`Cressey . .. . . . . . .
`. . . . .. 200/83 J X
`4/1948
`6/1958 Wood . . . . . . . . . . . .
`. . . . . . . .. 200/83 C
`4/1966
`Boettinger
`....... .. 200/83 N
`2/1967 ‘ Cooper ............................ .. 200/83 B
`
`
`
`1,665,381
`2,439,561
`2,839,630
`3,246,093
`3,302,269
`
`
`
` T’-«V/4
`\
` Q‘\C
`~
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`U.S. Patent March 16, 1976
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`3,944,769
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`3,944,769
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`PRESSURE SENSING MEANS AND METHOD FOR
`MAKING A PRESSURIZED CONTAINER MEANS
`AND SYSTEM UTILIZING THE SAME
`This is a continuation of application Ser. No.
`321,648, filed Jan. 8, 1973, now abandoned.
`This invention relates to an improved pressure sens-
`ing device and to a method for making such a pressure
`sensing device as well as to a pressurized container
`means and method for making the same.
`It is well known that a vehicular air bag safety system
`has now been provided wherein an inflatable bag is
`normally disposed in a flat, out of the way condition
`and is adapted to be almost instantaneously inflated by
`fluid pressure upon an impact of a vehicle with a harm
`producing object so as to protect one or more individu-
`als in the vehicle being engaged by the thus inflated
`bag. In order to inflate such safety air bag, a container
`means must be provided for the storing of such inflating
`fluid under pressure and in order for the system to
`function properly,
`the pressure in such container
`‘means must not increase or decrease beyond a prede-
`termined amount when that container means is at a
`certain temperature.
`For example, such fluid storage container means can
`each be charged with an inert gas, such as argon, he-
`lium, and the like, or a mixture of the same, to approxi-
`mately 2400 psi at room temperature and such con-
`tainer means must be adapted to maintain the stored
`gas pressure so that the same does not drop by more
`than approximately 200 psi or does not gain more than
`approximately 200 psi when at that same room temper-
`ature. Of course, such limits, as well as others hereinaf-
`ter set forth, are by way of example only and are not
`intended in any manner to place restrictions on the
`scope of the claimed invention.
`It is feature of applicant’s concurrently filed patent
`application, Ser. No. 322,071, filed Jan. 8, 1973, now
`U.S. Pat. No. 3,818,764 and entitled PRESSURE
`SENSING MEANS AND METHOD FOR A PRES-
`SURIZED CONTAINER MEANS AND SYSTEM
`UTILIZING THE SAME, to provide a means for de-
`tecting any adverse loss or gain in the pressure in such
`pressurized container means caused by means other
`than temperature change, such as pressure changes
`that are caused by a leak in the container means or
`other damage of the container means.
`In particular, one embodiment of the invention of the
`aforementioned pending patent application comprises
`a fluid operated sensing means carried by the container
`means in such a manner that the sensing means is sub-
`stantially surrounded by a reference pressure of the
`fluid of the container means so as to be temperature
`compensated thereby whereby any pressure changes of
`the fluid in the container means caused by temperature
`changes thereof are ineffective to cause a sensing
`thereof by the sensing means as the fluid of the sensing
`means is always at the same temperature as the fluid in
`the container means. Such sensing means comprises a
`fluid operated means having a movable wall inside the
`container means with that movable wall being changed
`by the pressure differential acting across the same and
`operating an electrical switch of a signal means to indi-
`cate when the pressure in the container means has
`changed from the desired value thereof to an undesired
`value thereof by means other than temperature change
`thereof.
`
`5
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`Thus, under extreme temperature variation condi-
`tions of the storage area for the fluid storage container
`for the vehicle air bag safety system, even though the
`same is inside the passenger compartment, the temper-
`ature of the fluid in the container means can reach
`approximately 220° F or minus 20° F and under these
`abient temperature conditions, the pressure within the
`container means can build to 3400 psi or go as low as
`1700 psi at the extreme temperature conditions thereof
`even though the same is approximately 2400 psi at
`room temperature. However, the sensing device of the
`aforementioned copending application is temperature
`compensated by the fluid of the container itself, so that
`the temperature of the fluid operated sensing device is
`the same as the temperature of the fluid in the con-
`tainer means. Thus, such pressure changes caused by
`extreme temperature conditions will not cause a false
`indication that the pressure within the container means
`has been adversely affected by means other than tem-
`perature.
`The aforementioned copending patent application
`teaches that the fluid in the sensing means must initially
`be at the same pressure level as the pressure level of the
`fluid initially charged into the main container means
`and, such copending patent application states that the
`sensing means and the container means can be simulta-
`neously charged with the same fluid and to the same
`pressure level.
`However, it has been found according to the teach-
`ings of this invention that it may be desirable to charge
`the sensing means with the its fluid remote from the
`main container means so that such percharged sensing
`means can thereafter be assembled inside the container
`means for the previously mentioned temperature com-
`pensating purposes with the container means subse-
`quently being charged with its fluid independently of
`the precharging of the sensing means and still have the
`sensing means perform its function of thereafter detect-
`ing any loss in the pressure in the main container means
`caused by a leak of fluid- from the main container
`means or other damage thereof as will be apparent
`hereinafter.
`
`Accordingly, it is a feature of this invention to pro-
`vide an improved pressure sensing means that can be
`precharged with its pressure fluid and which will not be
`adversely affected thereby,'such as by being given an
`adverse permanent set by such percharging thereof, so
`that the same can thereafter be utilized with a pressur-
`ized container means
`to sense pressure changes
`therein.
`
`In particular, one embodiment of this invention pro-
`vides a sensing means having a housing means provided
`with a chamber therein. A2 double wall fluid operated
`device is disposed in the chamber of the housing means
`and is carried by the same, the walls of the device defm-
`ing a chamber therebetween that is interconnected to
`the exterior of the housing means by a passage means.
`A charge of pressure fluid is sealed in the chamber of
`the housing means and since the chamber of the double
`wall fluid operated device in an atmospheric condition,
`the pressure of the fluid in the chamber of the housing
`means holds the walls of the device in a collapsed abut-
`ting condition. Since both walls are moved toward each
`other by the surrounding fluid pressure in the chamber
`of the housing means so as to be held in intimate
`contact against each other, no adverse permanent set is
`provided on the walls of the fluid operated device even
`though the percharged sensing means is stored for a
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`relatively long period of time. Such sensing means can
`‘thereafter be assembled inside the container means of a
`vehicular air bag safety system and the container means
`can be subsequently charged with pressure fluid to the
`desired level thereof which, according to the teachings
`of this invention, is to substantially the same pressure
`level as the pressure level of the precharged fluid that is
`sealed in the chamber of the housing means of the
`sensing means whereby the chamber inside the fluid
`operated device ‘is now interconnected to the fluid
`pressure in the main‘ container means and will cause the
`movable walls thereof to expand outwardly to a certain
`positionlbecause of the resulting pressure differential
`now acting across such walls.‘
`When the pressure differential across the walls of the
`sensing meansvis at an acceptable level, one of the walls
`of the fluid operating device can be utilized to make
`contact withvva contact means so as to continuously
`indicate that the pressure level within the main con-
`tainer means is at -an acceptable level. However, should
`the pressure differential acting across such wall of the
`fluid operated device increase because of a loss of fluid
`pressure in the main container means, such as through
`a- leak thereof or the like,’ such movable wall will move
`away from the contact means by such resulting increase
`in pressure differential across the same and thereby
`interrupt an‘ electrical circuit so that an indicator or
`alarm will be activated to provide means for indicating
`that the pressure level within the main container means
`has fallen below an acceptable level for safe operation
`-of the vehicular air bag safetysystem.
`> Therefore, it is an object of this invention to provide
`-an improved "pressure sensing means having one or
`more of the novel features of this invention as set forth
`above or hereinafter shown intdescribed;
`to provide a
`Anothercobject of this invention .is
`method for making such a fluid operated pressure sens-
`'ing means,
`-.
`V
`»
`.
`:
`’ Another object of this invention is to provide an
`‘improved pressurized container means for a vehicular
`airbag safety system and the like.
`.
`.
`Another object of this invention is
`to provide a
`-m’ethod~for‘making such a pressurized container means
`or. the like."-"
`-
`’
`»
`»
`'
`I
`’
`
`Other objects; uses and advantages of this invention
`‘ are apparent from the reading of this description which
`proceeds with reference to the accompanying drawings
`showing a‘ part thereof and wherein:
`FIG. 1 is~a schematic view illustrating the vehicular
`air bag safety system of this invention.
`~FIG..2 is a side view of the improved fluid operated
`‘ pressure sensing means of this invention.
`FIG. 3 is an enlarged, cross—sectional view taken
`substantiallyon line 3-3 of FIG. 2, FIG. 3 illustrating
`the fluid operated pressure sensing means before the
`same has been charged with its fluid.
`FIG. 4 is a view similar to FIG. 3 and illustrates the
`«fluid operated pressure sensing means after the same
`has been precharged with its fluid.
`— FIG. 5 is a View similar to FIG. 4 and illustrates the
`fluid operated pressure sensing means of this invention
`afterthe same has been disposed within a main con-
`tainer means that has also been subsequently charged
`with -its pressure fluid.
`.
`FIG. 6 is a. fragmentary schematic view illustrating
`‘ how the. pressure sensing means of this invention can be
`mounted within the main container means and can be
`utilized to indicate loss of pressure therein.
`
`4
`While the various features of this invention are here-
`inafter described and illustrated as being particularly
`adaptable for providing pressure sensing means for the
`pressurized container means of a vehicular air bag
`safety means, it is to be understood that the various
`features of this invention can be utilized singularly or in
`any combination thereof "to provide fluid operated
`sensing means for other devices as desired.
`Therefore, this invention is not to be limited to only
`the embodiment illustrated in the drawings, because
`the drawings are merely utilized to illustrate one of the
`wide variety of the uses of this invention.
`Referring now to FIG. 1,ia vehicular air bag safety
`system is generally indicated by the reference numeral
`20 and comprises an air bag structure 21 adapted to be
`normally stored in a collapsed out of the way condition
`but being adapted to be substantially instantaneously
`inflated as schematically illustrated in FIG. 1 by being
`fluidly interconnected to. a pressurized container means
`22 by suitable means 23 that is actuated by an impact
`of the vehicle against a harm producing object in a
`manner well known in the art whereby the details of the
`same need not be further described in order to under-
`stand the features of this invention.
`.
`The system 20 of. this invention includes a signal
`producing device 24, such as an‘ alarm, lamp, or other
`indicator which will be activated by the pressure sens-
`ing means of this invention in a manner later to be
`described when the pressure sensing means detects an
`adverse change" in the pressure of the fluid in the stor-
`age container means 22.
`‘
`A
`As illustrated in FIGS. 2 and 3, the pressure sensing
`means of this invention is generally indicated by" the
`reference numeral 25 and ‘comprises a‘ housing means
`26 that can be formed from a pair of parts 27 and 28
`assembled together to provide a chamber 29 therebe-
`tween ‘and within the housing means 26. While the
`housing part 28 is illustrated as being formed of electri-
`cally insulating material, it is to be ‘understood that the
`same could be formed of electrically conductive mate-
`rial’ if desired as will be apparent hereinafter.
`A double wall fluid operated device that is generally
`indicated by the reference numeral 30 is disposed
`within the chamber 29 of the housing. means 26 and is
`carried by the same, the device 30 comprising a pair of
`annular cup-shaped diaphragm walls 31 and 32 respec-
`‘ tively being secured together at their outer peripheries
`33 and 34 in a manner well known in the art and being
`adapted to define a chamber 36 therebetween.
`The walls 31 and 32 are respectively corrugated by a
`plurality of annular flutes 35 which are adapted to
`intimately and readily nest within one another in the
`manner illustrated in FIG. 4 for a purpose hereinafter
`described.
`.
`The wall 32 of the device 30 has its central portion 76
`secured to a tubular member 37 sealed through an
`opening 38 in the housing part 28 whereby the tubular
`member 37 carries the double wall device 30 and since
`the tubular member 37 is securedto the housing means
`28 and has an enlarged annular part 39 disposed within
`the chamber 29 so that the same cannot, pass through
`the opening 38 in the housingpart 28, the tubular part
`37— secures the device- 30 to the housing means 26
`within the chamber 29 thereof. The tubular member 37
`has a passage 40 passing longitudinallyVtherethrough
`and being aligned with an opening 41 formed through
`the central part 76 of the wall 32 so that the passage 40
`is in fluid communication with theichamber 36 of the
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`3,944,769
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`'deviéé".30 and, thu‘s,1:fluidly‘ interconnects thezchamber
`-terminal 5:5 that projeots‘out'ofx.the- container means -22
`36‘of‘the device‘ 30“ to the exteriorof» the housing means
`*and is electrically. insulated=therefrom by an electrically
`*26“f6r= a‘pur'pose here'inafte’ridesoril’a‘ed.r
`4
`-.
`"in'sulating= plug -56,:'which. ‘also carries’ another, terminal
`~ ~: The othe'r"walll i 3l"‘o‘f the‘ devicef?301.éhas,.«its:: central
`457 in: electrically spaced relationstotthe-terminal.55.
`.p’or«ti<§rl -42I‘fonned in'“a-_=*cup shape .t’o_::,provide,a».,flat 75 a«.'Fhe~terrninal 55 isradapted to be interconnected by a
`-circular part 43 extending completely beyondvthe:-flutes
`-«“lead:’58 to one side 59 of the. indicatingdevice 24 while
`35 of the ‘wall 31 sogais. to be adap_ted=to'_ abut against :-a
`-the- other side 60 thereof is adapted to«‘be:intercon-
`flat ‘en‘d44—Tof a tenninal rod 45 =having its upper end 46
`=nec_t'ed by a lead‘ 61'to?onexside- 62 oféan electrical
`iprojectin‘g';_in'to~ the ch'ambe'r<29 of,the sensing means 25
`power source 63,? such as the automobile battery that is
`in‘ -thevlmanner illustrated. in FlG.;~5 for ;the, purpose
`illustrated. The other? side 64 of :the «electr—ical.,power
`=her‘e’rinafter described: ,
`:
`:;-;
`.
`: ..:
`'
`,1
`‘-2, ~11
`source 63 is vadaptedto ‘be interconnected by the; lead
`~rThe‘:t'enninal rod 45 is secured -to the housing.part.27
`-65 ‘to the ‘terminal.?'57:I»-Thei:terminal- 57,
`in .« turn,
`is
`while being electrically insulated therefrom. by an .elec-
`adapted’ to be "interconnected byvthevlead :66 to the
`-trically insulating sleeve. 47 so that the upper end _.4_6,of
`,
`tubular’ member 37-« of thefsensing-device 30- whereby
`the rod 45.projects.»into‘ thex,chfamb.er-29,, and the lower 15> theside 64 ofthe power. source 63 :is,'in effect, electri-
`end 48:thereof projects out gfthe h0using_mean_s 26 for
`vcallyiiinterconnected to. the wall:3l of the. device: 30
`lead attachment‘purposes§as.will_;be,,apparent hereinaf-
`while the“terminal rod 45 is electrically«interconnected
`.1Cl'. "§'.I="".’_-‘-"','
`1"
`':‘
`-:
`,
`J N,’ .,
`,
`;v.,_».
`'
`i,
`,
`to 'the’oth_er side "62.ofthe power source 63.“
`«.
`.-
`The». terminal «rod->-,45. is «_ass.e,m.ble,d_ to w.the._hqu§ing
`-‘ The indicators24- is so‘ constructed. and arranged that
`means‘26 ,in such.a manner that the upper. surface
`of
`the same indicates that the system is safe as-vlong as an
`the upper. end 46 of the rod_45«_is_slightly spaced from
`electrical current passes therethrough so that.when the
`. the;_,surt;'ac._e_ 43 of the_wall 31 of .the device gglwhenythe
`‘electrical ‘current ‘passing through‘ the indicator.-24 zis
`-»'b'roken', thesame indicates that.~an.-iunsafe condition
`chamber 29 of the housing;rnea_ns._26 andthe chamber
`vexistsesuch
`c.2t;the.deric¢ 3.<)..==.r..e, a.t..atr.nosp.h.~°=ri9 c9raditi°ns..-as
`-as‘ by flashing a light,§ sounding, an alarm,
`25‘~‘et‘c.
`~
`,illus.trates1.;i_n FIG, .3 , for a .purp9.se _hetéin.afte: (de-
`.:- After‘ the precharged device 2'5.or' this iniventioun is
`:‘5C1'-ibefii.-.m
`».
`V
`i
`.
`,."l?he ho,using'part 28 carriesia fill, tube
`th'athasf.its
`assembled in the chamber 52 ofthe container means -22
`
`passage ’ means-:50’ in
`.
`.
`.
`fluid .co.
`.mupica ‘tin ,'with,the
`" in themanner illustrated in FIG- 6,-;th.e chamber 52.Aof
`chamber 29”of the housing frieans
`_
`_
`. the container means 22-can be 'charged:w,ith its pressur-
`the pressure sensin
`‘been assembled
`: iz'ed fluid through a filling tube 67, FIG; 6, .to_ the. prede-
`in’-’fl1.e‘.rriafiri'¢=.r.ilIustrarcd. in . FIG-. .34 ”th5.="‘cti.a:1iber 29
`terminedpressure level athereof. When the -pressure
`t_her§of'is‘adapted to be,p_re;cmt;rg¢‘d ‘with’ pressure and
`level within the chamber S2:reaches. substantially the
`
`_anii
`_
`ssure level gtljatjis sub§tantially'thé‘sai_ifé{as
`~4same~pressure-level as"-within the.»ch-amber 29. ofI the
`the desired pressure‘ level
`isiti‘) be Amaiintained in‘ the
`35. ~‘sensing=device 30 of the sensing means.»25, the chamber
`(cor_i,tai,ne:r rnear1‘s‘,",22_‘ (if: theiaiif ;brag‘ safety” system‘
`36vof thewdevice 30‘ within the -chamber 29 of the hous-
`20- It. is ireférred‘ .tha.tth. fli+ii1’.b¢in£z’§harJges1 ifito ifie
`ing means 26 is nowareceiving pressure fluid-that is-in
`‘chamber _2,9,_,p'tf‘ the": ser”_1s_ing~_ ‘mfea}t_sj25' through the fill
`‘ the -chamber 52.: of: the container means~:22;.—and.lhas
`tube 49 be “f hesame type"of’flui_d that tbbe utilized
`caused the pressure differential across-thegwalls 31. and
`_in the main c.ontéii_jr1e_i“n1‘evai\1s_22}’lriiany event,'after the
`232 ofsthe device‘ 30 to decrease. so that when-the.,cham-
`1 chamber‘ '29" has been jchar’ged’jto“the“predetei‘rnined
`‘ber-52Iis charged to.a pressure :level«only slightly above
`' pressuré"l'e’§{él thereoffthe fill tube" 49 is? sealed ’c_lo'sed
`the pressure level in ithegchamber 29 .of the sensing
`,_;by any suitable means, such 'as"by'[the"weldin'g“ 451 ¢illus-
`device 25, the movable wall 31 is moved -by the pres-
`‘ tratied" in"FICij." 4’ whereby the "charge‘bfipréssure—“flu§d
`sure 'differential across-the: same in such :a manner ,that
`withinlthejéhamber '29 is corhpletely;’sé‘aled‘-from the
`=‘the'-flat part 43:thereof makes electrical eont_act;with
`‘45.
`"‘ex'te"r'ioi"o‘f the housing tfieéns 26$ 6
`‘: 2.
`<2‘
`" ‘= :'
`-
`the end surface 44of;the terminal rod .45.~in the manner
`Since the chamber 29 of the device 30“is!'at=atmo-
`5' illustratedin FIG; 5 to-thereby effectively complete the
`spheric condition, it can be seen that as the pressure
`‘ electrical circuit through ;the.indicator 24.-.Thus,.,,the
`fluid is being charged into the chamber 29, the result-
`indicator 24 will indicate that the container means 22 is
`ing pressure differential acting across the walls 31 and
`charged to the proper pressure level and that as long as
`32 of the device 30 causes the walls 31 and 32 to col-“
`the pressure in the chamber 52 of the container means
`lapse toward each other as illustrated in FIG. 4 and
`22 remains at such pressure level and does not fall
`have the flutes 35 thereof intimately fit within each
`below the same by approximately 200 psi or other
`pre-selected amount, the indicator 24 will have the
`other so that both walls 31 and 32 are pushing toward
`each other with the same force. Thus, neither wall 31
`electrical circuit completed therethrough by the sens-
`or 32 is overstressed by the charged pressure fluid
`ing means 25 in a manner illustrated in FIG. 5. Thus,
`within the chamber 29 and therefore will not take any
`the fill tube 67 can be sealed closed by the sealing
`means 68 illustrated in FIG. 6 and the container means
`adverse permanent set from the fluid pressure charge in
`the chamber 29 even though the charged device 25
`22 can now be utilized in the vehicular air bag safety
`may remain in a stored and precharged condition for a
`system 20 of FIG. 1.
`relatively long period of time before the same is utilized
`When the charged container means 22 is utilized in
`with the container means 22 for the air bag safety sys-
`the vehicular air bag safety system 20 as illustrated in
`tem 20.
`~
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`=
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`FIG. 1, the indicator 24 will continuously indicate that
`the pressure level within the container means 22 is at
`the proper pressure level for safe operation of the air
`bag 21.
`However, should the pressure within the chamber 52
`of the container means 22 fall approximately 200 psi
`below the initial charge value thereof, the resulting
`
`'=—4o
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`=50
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`'55
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`.60
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`65
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`The precharged sensing means 25 of this invention is
`adapted to be disposed within the main chamber 52 of
`the container means 22 in the manner illustrated in
`FIG. 6 and can be supported therein « by suitable
`bracket means 53. The terminal rod 45 of the device 25
`could be electrically interconnected by a lead 54 to a
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`pressure differential’ acting‘ across the wall‘ 31-of the
`device 30'of the sensing means-25 will cause the wall 31
`to have the central part 43 thereof move away from the
`end 44 of the terminal rod 45 and thereby break the
`electrical circuit therebetween and, thus, break. the’
`electrical circuit through the indicator 24 so that the
`indicator 24 will provide its warning function to the
`operator of the vehicle that the container means 22 for
`the air bag safety means 20 is in a damaged condition
`so that the same will not operate the air bag 21 -in the
`proper manner and must be immediately checked.
`If desired, the terminal 57 can be eliminated and the
`side 64 of the power source could be connected to
`ground while the housing part 28 of the sensing means
`25 could be formed of conductive material.and;.be'
`effectively interconnected to ground through I the
`bracket 53 and container means 22. Thus, in order for
`an electrical circuit tobe completed through the indi-
`cator 24, the wall 31 of the device 30 must make
`contact with the terminal rod 45.
`.
`.
`Therefore, it can be seen that this invention provides
`an improved fluid operated pressure sensing means that
`can have the fluid thereof precharged therein and such
`precharging of the pressure fluid therein will. not cause
`the movable wall means thereof to take an adverse
`permanent set, the pressure sensing means of this in-
`vention being adapted to be disposed within a main
`container means that is to be subsequently pressurized
`so that the same will be temperature compensated by
`the fluid pressure within the main container meansifor
`the reasons fully set forth in the aforementioned co-
`pending patent application.
`.
`»
`It can also be seen that this invent_ion.provides-a
`method for making such "a fluid operated sensing means
`as well‘as an improved pressurized container means
`andmethod of making the same.
`=
`-
`'
`r
`.
`.
`While the form and method of the invention now
`preferred have been disclosed’ and described as.re-
`quired by Patent Statutes, it is to» be -understood that
`other forms and methods can be utilized andstill come
`within the scope of the appended claims.
`A
`e
`.
`‘What is claimed is:
`'
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`l
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`1. In combination, a container means having a pres-
`surized fluid therein, and fluid operated sensing means
`' carried by said container means for sensing pressure
`changes within said container means; said sensing
`means and said container means being so constructed
`
`i-‘:18
`andvvarranged that said sensing means is temperature
`compensated by being disposed within said container
`means to be substantially surrounded by a reference
`- pressure‘ of said fluidlof said container means so that
`‘pressure changes of said fluid invsaid container means
`caused by’ temperature changes thereof are ineffective
`to cause sensing thereof by said sensing means_ as the
`‘fluid of said sensing means is at the same temperature
`as said fluid in said container ‘means, saidvfluid operated
`sensing means and said container means having been
`initially charged with their respective pressurized fluids
`to substantially the same pressure levels,”said sensing
`means comprising a*housing‘ means secured in said
`container; and» having a chamber therein, a double wall
`fluid operated “device disposed in said chamber of said
`. housing means and being carried by the same, said
`walls of said device ‘defining a, chamber -therebetween,
`said device having passage means interconnecting said
`‘chamber of said device to the exte‘r_ior‘o'f said housing
`means so as to be in fluid communication with said
`fluid in said container means’, and a‘ charge of pressure
`fluid sealed in‘ said chamber of said housing means to
`provide said pressurized fluid of said sensing means,
`said charge of fluid in said chamber of said housing
`means beingadapted to hold said walls of said device in
`intimate contact with each other throughout the entire
`*2 effective surface ‘areas thereof so that the same" will not ,
`take a permanent set ‘when the chamber therebetween
`is at atmospheric conditions;
`,
`’
`'
`—
`, 2. A combination as set forth’ in claim lpwherein a
`contact, means is carried by said housing means and is
`disposed within said chamber of said housing means,
`5 said device and said contact means being so con-
`35
`structed and arranged that one of ‘said walls makes
`contact" with said contact means as longfias the pressure
`value of the; fluid in. said chamber -of -said device ‘is
`substantially the same as the pressure value of theifluid
`sealed in said chamber-of said housing means.
`‘
`,
`3. A_combina_tion as set forth in"cla'it-n’ 2 wherein said
`contact means comprises a terminal rod insulated from
`said housing means and having one end‘ thereof dis-
`posed in said chamber to be contacted by saidone wall
`of said device. andhaving the other end -thereof project-
`ing out of said housing means for -exterior lead attach-
`ment thereto.
`_
`‘
`t
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`25
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`30.
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`40
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`45
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`at
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`*'a="_*
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`so,
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`,
`
`f.
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`55‘
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`'60
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`65
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