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Патент USA US2404578

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July 23, 1946.
J, w‘ LISKA'
_ ’
Filed July 26, 1940
2 Sheetsr-‘Sheet 1
Maj/v @Zafsta
BY Q2‘
July 23, 1946.‘
J_w.|_-1-sKA' '
Filéd July 26, 1940
2 Sheets-Sheet 2
Patented July 23, 1946
John W. Liska, Akron, Ohio, assignor to The Fire; i '
stone Tire/8r Rubber Company,‘ Akron, Ohio, a
corporation of Ohio
Application July 26, 1940, Serial No. 347,713 '
8 Claims. (Cl. 152-342)
This, invention relates to ?uid retaining (con
tainers for pneumatic tires and more particularly
to multiple chamber safety inner tubes.
Heretofore, double chamber inner tubes have
been known in which there are two concentric
chambers, with means for introducing pressure
?uid into one of the chambers and a very small
passage between the two chambers to permit‘ the
pressure ?uid to ?ow from one chamber into the
~ other and permit equalization of ‘pressure between
character mentioned, between the two chamber
which will be responsive to a pressure differential
to control the ?ow of ?uid from the inner to the
outer chamber in the event of a blowout or rup
ture in the outer chamber; to provide such an im
proved valve means which will be positive in its
‘action, will be inexpensive to manufacture and
will be of such shape as to facilitate its incorpora
tion in a safety tube of the character above men
Other and further objects will be readily appar
the chambers during operation. However, in
ent from the following description, considered in
these previous devices therelative size of this pas
connection with the accompanying drawings, in
sage between the chambers has been deliberately
kept small because it was thought necessary in
Figure l is a perspective view of an inner tube
order to retain its safety characteristics. In the 15
embodying the invention, a part thereof being
event of a blowout or rupture in the outer cham
broken away to show the underlying structure;
ber, a large passage would permit the air to rush
Figure2 is a section, on a larger scale, on the
out so fast from the inner chamber that. the
line 2—2 of Figure l.
highly desirable safety characteristics would be
substantially nulli?ed.’ A great disadvantage of 20 Figure 3 is a section, on the same scale as‘Fig
ure 2, on the line 3-3 of Figure 1, to illustrate the
such a very small passage is that considerable
time is necessary to effect in?ation. Also with a
relative size of the cross sectional areas of the
primary in?ation means and the passage between
very small passage it is practically impossible to
the two chambers.
get enough of the pressure ?uid out of the inner
chamber to permit demounting of the tire because 25 Figure 4 is an enlarged Sectl0n70f the, valve
means. between the chambers, shown in Figures 2
as the pressure in the chamber continues to de
and 5, looking in the direction indicated by the
crease, its rate of ?ow through the small passage
progressively becomes less and less. Another dise
arrows 4-4 of Figure 6;
Figure 5 is a plan View of _ the valve means
advantage is that unless the e?ective cross sec
tional area of the passage is at least as great as 80 shown in Figures 2 and'4, looking in the direction
indicated by the arrows 5-—5 in Figure 2;
the eifective cross ‘sectional'area of the primary
Figure 6 is a modi?ed form of the embodiment
in?ating valve for in?ating the tube from the ex
ternal source, a pressure differential will develop ,
between the two chambers and an inaccurate in
shown in Figures 4 and 5;
, '
Figure '7 is a vertical section, on the line 1-1
dication of the pressure in'one of‘ the chambers 35 of Figure 8, of a further modi?ed form of the
valve; and
will result.
Figure 8 is a plan view of Figure 7.
Accordingly, a major object of the invention is
An embodiment of thelpresent invention is 11
to overcome the above disadvantages.
lustrated by the fundamental elements of the
1 More speci?cally, the objects are to provide a
double chamber safety tube, with means for 'nOr
mally permitting rapid in?ation and de?ation of
both chambers of the tube while controlling the
40 combination; an annular tubular body I l of elas
tic rubber composition orv composition having
similar characteristics, forming an outer‘ cham
ber ill; a concentric wall l2 which serves ‘as part
of ‘a wall of'an inner chamber l5 inside of the
outer chamber; a primary in?ation valve l3 by
which pressure ?uid from an external source may
be introduced into the inner chamber 15; and a
passage [4 in the wall I2 with which there is as
sociated a valve It to control the ?ow of pressure
I greater, than the effective area of the passage of
the primary in?ating means, together with valve 50 ?uid from the inner to the outer chamber in the
event of a blow out or rupture in the wall of the
means associated with such passage or passages
outer chamber. The aperture or passage l4 isv at
responsive to a pressure di?erential to control or
least as large, and preferably larger‘ than, the
reduce the effective cross sectional area of the
area of the primary in?ation valve I3 and is nor
‘passages between the chambers; .to provide an
?ow of ?uid from the inner to the outer chamber
in the event of a blowout or rupture in the outer
chamber; to provide such a double chamber safe
ty tube with a passage or passages between the
two chambers of total effective cross sectional
area, at least as great, but preferably slightly
improved valve means in ansafety tube of the
mally' open and unaffected ‘by any ?ow of pres
sure ?uid through the valve I3 in either direction,
ner chamber and the outer chamber except for
the small ori?ce 25. The ori?ce 25 is desirable
to insure equalization of pressure between the two
chambers and to permit the slow escape of ?uid
pressure from the inner chamber in the event of
a rupture in the outer chamber for the purpose
the valve I6 being responsive to a pressure di?er
“ ential to be forced toward the wall l2 when there
is a greater pressure in the inner chamber I5 than
in the outer chamber ID, as in the event of a
blow out or rupture in the outer chamber. The
of discouraging the driver from continuing to
combined area of apertures I’!v in the ,?exible‘part
drive on'the' inner chamber. It, will ‘be readily
of the valve; [Bis-greater than the area of thepas
apparent‘th'at any mechanical equivalent of the
sage Ill-‘and these apertures "have he‘ essential
bearing on the invention, they merely being pres.-_ 1.0 ori?ce 25 can be used without departing from the
‘spirit of the invention. For example, instead of
,thaori?ce. a; recess. may be provided in the an-v
ent to complete the communication between the
inner and outer chambers.
The present invention is adaptable to;
nular rib 2;} or a projection may be provided,
of a multiple chamber tube“ n'd'i'sjnot ‘h
‘ veither-on the, ribfor on the surface of the wall
to the particular type of tubeshbwn'for purposes‘
11 t o prevent the; valve it from completely clos
ing the passage between the two chambers.
of illustration. In the illustration shown, the
wall I2 is made of substantiallyinel'astic rubber-.-v
Thejpassage. M; in the wall [2 has an effective -
ized fabric similar to the conventional tiracasing . V
plies in which the reenforcing elements or cords" '
cross sectional area which is preferably slightly
lar body ll adjacent the respective bead" regions
valves areisubjected- are takenin-to considera
greater than the cross sectional area of the pri
are arranged at an angle to the axis of the tube 20 mary in?ating valve [3. - In considering the effec
tive cross» section, the pressures to. whichéthese
and is joined by vulcanization to the outer tubu
tion. For. instance; if; thetphysicalvarea» of~ the
of the tube. indicated at 18,‘ [8. However, as far
‘valve l.3l and the valve I6were1exactly the same,
as the basic aspect of this invention is concerned,
. it is not‘ necessary to have the margins of the 25 the effective cross sectional area of thevalvel-S,
for. all. practical. purposes, would be; greater; than
wall“ joined to the tubular body vll'. vIt is only
vthat of: the. valve l?, becausethe in?ating valve
‘ necessary that the wall l2l'be arranged inside of
is. will be subjected to the total-pressure’ of: the
‘ the'tubular body H andv serve as a parto? a .
source. of in?ating?uid;
‘ common wall between the outer chamber, and a
the.areas- are equal
chambergdisposed radially inwardly of the tread
andthe valve I 3;is.connectedtoahexternallsource .
‘ part of the outer wall ll. V'In'a safety 'tube'of
of high ?uid pressure, arpressure differential will
develop. between: the inner! and; outer; chambers.
It is. de?nitely... an obj ectof: this invent-ionrto avoid
this. Eorthisreason, the crosssectional area. of
thepassage. l4. isenough larger than. the area
of. the valve l3; to .insurethat. no. substantialpres
sure differential between the. two: chambers will
this type, the'inner'wall l2 ismerely adapted ‘
‘to be disposed’ in a'pos’ition to protect, it from
the impacts and possible punctures to which the
‘ tread part of the tire is'subjected and is. adapted
‘ ‘to retain a certain portion of- the original ?uid
pressurerland to serve asa “boot” on reenforce being; in?ated;v from the
ment' for a'rupture in the tire casing-- when the
latter ruptures.
Theimproved inner tubeismounted in. apneu
matic. tire. casing in theusualv manner. During
in?ation of thetube, airpasses?rstinto. the inner
chamber l,5__ and; then. through the. apertures l1
inthevalve I?and. the.passage,-v I 4 in thetwall. I2
' The valve I5,‘ as shown, is in'the‘form of-a cir
,‘ "cular rubber disc and-‘has a peripheral‘ ?ange 2|
which is integrally bonded by" vulcanization to
g the inner. face of‘the wall~ l2‘ and is preferably
disposed substantially concen-trictothe passage
l4,‘ but in any event is disposed sothat the passage 1‘
I4’ is‘ fwithin’v the region 'where' the flange 21- is
joined to the'wall [2. The valve l6'is generally
’ dome-shaped and has an ‘annular. concavo-con
into _ the; outer, chamber... LII’, the. valve In. remain.
ins ones because .of. thesubstantiallyhqual. ?uid
pressure .onboth sidesef tlrlerwallv I2. Theearr
rangementenablesethe two .chambers ; of; the tube
located. v'I'his concavo-convex region? is. readily
concurrently; tojbe, in?ated; Without any._;s.ubstan:
tial, pressure. di?erential. developing between; the
two chambers: There. isznorvtaste Qfrtimeesuch
' ?exible to enable operation of'the. valveJ?v with
‘ out‘ subjecting any part thereof’ to tensilestrains.
verx-smalt aperturesbetween; the twoechambers
‘ vex region 22..disp_osed inwardly of ‘the ?ange-2i,
in which region a plurality of apertures l'l-"are -'
as..-Qccl1rs.vrhen .tbeair; .requiredito.passthroush
andin?ationthrough thesririmaryin?atingevalye
Axially of the; concavo-convexregion 212,..aplanar
disc portion 23.'is.integra1ly.formedandshas an »;
annular rib 24 on one side thereof, which ‘serves
as the sealing. element of (the, valve. . Theirib. 24
‘ is adaptedto "contact. the wall. l21t0 co'ntrolthe
‘ ?ow of?uid pressure through the passage. I41, '
so that it is necessary that the valve; Iii be so
‘ disposed. on the wall 12 that. this rib. 24. com
pletely'surrounds, the passage H3 in order for the
j valve to function most ef?ciently. The disc por
‘ tion 23,‘ while of. ?exible rubber, is‘ofsu?icient
sti?fnessito prevent it from being forced through
1 the. passage: l4, and. is providedwith an‘axial
bl'eeder ori?ce 2.5..which provides a predetermined
‘ minimum passage between. the [two chambers
when the valve 16‘ closes. against the wall- I2. 'It
lireqlliresno longer timethamthat required: for
in?ating a single chamber tube. Moreouer; there
isno nos?ibllity; 01?
inaccurate indication». of
the fluid pressllreiin.eith'enofrthe.twdchambers.
The pressuredndicated at.v thevalve. l 3ewilltalways
be, a cqrrect-indicatiom of; the. ?uidz-pressure- .in
both chambers.
When . thettire and .tube are in in?ated condi
tion and-a blowout; or; ruptprebccurs, the’. outer
chamber I 0 .IofZ-the. tube. is. rapidly; de?ated; and
causes-a pressure ldi?erential; between-the cham.
bers Ill-and I5;
the,- centralportion 2 3; of thevalve l 6.;to. be .forced
toward the...w.al1. l2: so thatithe; annular..rib-2..4
will icontacttheinside ofgtherwall. IZEan‘d thereby
i will be, readily apparent that sincethe valvel?
greatly. Ethics. the rate..- of » ?om. ofi the: pressure
\ is arrangedgon the inner face of the wall» 12, any 70 ?uid. from. the. inner .to .the.~. outer .chamber.>. As
appreciablygreater pressure in the innencham
ber l5; than in the. outerchamber. l-lLwill force
explained above,v however,.:the .valve. is designed
‘ the central partof thevalve l?outwardlytoward
i .the,wall1l2juntil= the annular rib 24c0ntacts1the
.the.~,inner.chamberto; gradually escape therefrom;
Th'etimerrequired for; complete de?ationvof the
latter and closes communication between the in
withv a . by-pass 25; to permit ». the, pressure . from
inner chamber may be from approximately one
to six minutes} Itshould-belong- enough toen
able the driver-of the-vehicleto bring the latter
under control, ‘or to a'stop, but not long enough
to encourage him to‘driveilon the partly‘ de?ated
tube, since this would eventually result in serious
damage to the tire and tube. ,
~ ~
' sponsive to. pressure- differentialbbetween/said
chambers'ifor,controlling the rate bf'?uidlfmw
through said passage,‘ said valveimeansicompris
ing.‘ an annular 1 disc havingiits ‘limiter;i edge Yise
curedi-to;theiginsideliofl said wall Ilin? airegionisiir
rounding saidi’passage,-'{said va'lve'~liavihg--'alceni
l . -
tral recessed :portioni'h'aving a surfacei'adjacent
i The valve between the two chambersmay take
varied forms, as shown by modi?cations of Fig;
to-‘butrspaced fromv said walloverllsaid passage;
ures 6,7,1and‘8. 7'
thesurface of saidlrecessed’rportioh 'adjacent'to -
In Figure 6 they valve 26 "is shown-‘withathick
said’? l'wallil- having .a- ‘projection thereon ‘in the
immediate‘region ofzsaid'passageto prevent said
ened‘central region 33- having ' an ‘ aperture .35
therein. The undersurface of the-central region
centrallportion .fromlcom'pletely closing said‘jpas
33 ‘is planar." Otherwise ‘this ‘modification is sim
ilar to 'thatof Figure 4.
. 2. 1 A I valve} in‘ combination ‘with
a ‘ vseparating
‘ Figures 7 'and‘8 show a further modi?ed form -
wall, having an opening therethro'ughcomprising
in 7'which thevalve 36‘ comprises an annular disc
a- valve; chamber ‘formed ' of 1 {flexible imaterial at;
similarto that of the‘ previous ?gures, but hav¢
ing a‘ recess 31’which'spaces the'central region
431fr'om' the dividing wall |2~betweenthe inner
chamber sid'eco'f said-‘wall, - said ?exible imatefial
tached- around, said‘ opening on ‘the inner -"- air
normally, beingrmaint'ained" away from" said "well
and l'outer chambers when the‘ outeriedg'e ofthe 20 at the position‘? of: 'saidppening', ven’ ~means‘iiri
said: flexible. material at"a1@positionl1adapte ‘to
disc is-attached-to thewall-z-v v‘By: reason ofi the I
recess. the outer area of ‘the'ice'ntral region’iwill " contactsaid .walllfupong collapse of said ‘flexible
bevflexiblef tov facilitate operation ‘of the‘valve‘
material, -.: a i port: \ in‘? I said “ ?exible material _posi;'—>
tioned toqr'egister‘.withl‘said opening inis'aid‘asep'aé '
against thewallvl2. -The valveiias a thickened
rating- wall upon ‘collapse-"of; said3 flexible ma
portion 44. which servesfas thevalveelement and .
it is preferably of sufficient thickness'to prevent
terial, the ‘collapse of said'lr?exible material‘being '
caused by. aquick release ,l‘of substantial air ‘pres;
sure onthezotherside of said wall, movement of
it from being pushed into. theaperture L4 in the
wall, in the event of high pressure differential
the ?exible material ofthjevalve against‘the sép-f
when the outenchamberblows out or ruptures.
This thickened portion could serveas' aweighted 30 arating, wall sealing. the’ vents, ' the port ~ means
valve elementto close in response to centrifugal
maintaining ail-"communication with the opening
force when the wheel operates above a predeterl
inzsaid separating wallat all times.
mined speed. . The apertures 41v areto provide
Means :for controlling -moverne'nt - of Jan
communication between the chambers, since the
through‘; :a- separating wall? having anv opening
valve 38 is placed over; the aperture [4 inv the 35 therethroughbetween ‘air pressure ‘chambers’ of
ajpsafety {tube or the like comprising‘ a substani
wall I2. The-side of: the‘ central ‘region 43 ad
tially‘ collapsible valve chamber over said'o'peni
'J'acent the wall 12 is provided with‘ a transverse
rib 48 which vprevents the valve 36 from. tightly
ing on one side of saidis'eparating wall, saidv'alv'é
closing the aperture Mn It~is desired. to‘keep
the valve from closing tightly in order to dis
courage a drivernfrom continuing .to'drive the
vehicle after the outer chamber .has blown out
or ruptured.
It is to be understood that-'Jthe
combined area or. the apertures 41 is greater than
the area of the passage [4 in the wall l2. As will 45
be readily apparent from the foregoing descrip
tion, the valve 36 will be forced against the wall
I2 to reduce the flow of air through the passage
I4 in the event the outer chamber blows out.
It is to be understood that the valves shown in
Figures 7 and 8 will be attached to the underside
of the wall 12 in a manner similar to the embodie
chamber having a cover-"portion, vent'means-in
said cover-portion forthe passage of air into {and
from saidvalve chamber, flange means between‘
the vent means and the opening preventing sub
stantial movement of air' through said ivent means
.to saidopening'when'v said valve‘ chamber'is col‘
lapsed, a restricted port through said cover posi
tioned to register with the opening, the cover nor
mally remaining spaced from said separating wall,
and said cover being adapted under difference in
pressures such as is caused by sudden substan- ’
tial failure of the air pressure on'the side of said .
separating wall opposite to that on which said
cover is located, to collapse and thus vnormally
close the vent means against the passage of air
ments previously described.
through said vent means into the opening‘ in the
It is to be understood that where, in the speci
?cation and claims, the singular is used, the 65 separating wall, the restricted port normally re
maining open to the passage of air through the
plural is also contemplated where the cumula
tive effect of the plural elements is the same as
that of a larger single element.
The description which has been given, recites
separating wall opening.
4. A valve in combination with a separating
wall having an opening therethrough, comprising
more or less detail of the particular embodiments 60' a collapsible valve chamber over said opening on
one side of said separating wall, vent means for
of the invention, which are set forth as new and
useful. However, it is to be understood that the
invention is not limited to exact details of con
struction, because it is manifest that changes and
modi?cations may be made within the scope of 65
the appended claims without departing from the
spirit of the invention. Also, the invention is
the passage of air to and from‘said collapsible
valve chamber, means in said collapsible valve
chamber, positioned to prevent the passage of air
between said vent means and said opening upon
collapse of said valve chamber, a restricted port
in said valve chamber normally registering with.
said opening for the passage of air regardlessof
the collapse of said valve chamber, said valve
inherent uses or functions.
70 chamber being adapted to collapse upon the sud
What is claimed is:
den removal of substantial air pressure on the
1. An inner tube for pneumatic tires, said inner
other side of said separating wall from said valve
not limited to the applications or uses described,
but it is to be understood as contemplating all
tube comprising an outer chamber and an in
ner chamber, a Wall dividing said chambers, valve
5. Means for controlling movement of air
means operably associated with said passage re 75 through a wall of a safety tube or the like com
prising'a separating wallhavinga po'rttherein,
permit pressure ?uidtapassfreely therethrough
torgthe interpassage 50f ?uid therethroug-h; a?exe
without collapsing said rubberistructure in the ab
ible collapsible, cover arranged over said port and
sence of substantial pressure di?erentia-l on .012.- '
securedytorsaidywall onone side-thereof,- said '
posit'e side's'of said rubber structure;
coyergvand ,wallibeing normally: spaced‘ from. one
7 7. A valve in combination with a separating
anotherland forming aivalve jchambena vent pase
sageyinasaid cover, connecting-maid valve cham
wall for an inner tubeof the twocompartment
typersaid tube having an inner and outerwall,
a port in the inner wall through which the tube
in?ation pressure in said compartments nor
mally equalizes, a rubber valve’ portion secured to
the inside surface; of the inner-wall and ‘being dis
posed; oversaid port, said" valve portion having a
ber with the exterior of said chamber-on-said one
side; i isaidliwall' and outrofgregister with-said ' ‘
.pgrt,r;a bleed opening; in- said ‘cover 1 connecting
saiq valve’.- chambergwithiythe saidexterior and
adapted to register with said port; ‘ said '. vent
passage normally connecting with 7 said port
throughrthevalve chamber to interpas‘s ?uid. be‘
tween said exterior on. sa-idone sidejof the‘ Wall,
andthe {other side £of, the wall; whereby collapse
oi said-lcover andvalvejchamber in response .to- a
preponderance (of pressure; pexteriorly "oi ; said
said valve Lchamber; anden the other side of “said
a ,
‘ bleede'r hole aligned with saidport, said hole ibe-i ‘
ing relatively small in relation to‘said port,t_said
valve portion having its :edge portions perma
nently attached to said- inside surface and having
its centra1 portion normally ‘spaced apart there-,
chamber 011 said one. sidepf the wall over‘ that in
1 walltinterr-upte‘the/inter pass‘a'geot ?uidvbe‘tween
from thereby forming acollapsible valve cham
ber, an annular rib encirclingqsaid' hole-andupro
jecting'into ,said' chamber and being adaptedto
thepn‘e side of H saidlw'all exteriorly ‘(of said‘: chame '
seatyonasaicl inner wall about said port when said
' chamber is in- collapsed condition- with said port, a
ber andtheotheriside,‘except through. said‘bleed 7
> I plurality .of apertures; forined'throu'gh ‘said .rub-v
' opening and portini registry therewith . r ;
her-valve portio‘nain‘ the area théreof'ioutsiide' the
6,1 Aivalve for ;a pneumatic'tire‘inner‘tube such
circle. formed by said rib, said apertures having
at least asrgre'atlcombin'ed‘ e?ective' cross sec;
ascemprisesoan internal non-'elastic‘wall divid
tional areaas the‘ cross sectional area ofrs'aid
ing it into- inner, andouter chambers: that are in
communication; with each other through a; pas
8.. A valve in- .com'binati'on with a separating
sage in; said‘ wall, said valve consisting or a vuni-‘
tar shallow, dish-shaped rubber structure com 30 wall havingfanopening therethrough, ‘comprising
prlisingta peripheral ,?ange adapted to bei'fat-e
a collapsible valve wall providing a chamber‘ over
tached to said internal tube-ewajll in concentric
said opening on one'side ofsaidl separating wall,
vent means for‘ thewpassage of airi-to' and. from
' relation to?the passage therethrough with, the
bottom portiongoi ' said structure-spaced apart
‘7 therefrom, said rubber structure being collapsible
under impetus of pressure ‘differential? on opposite
sides‘thereof, a bleederi ori?ce through-theater) *7
‘ 7 portion ofsaid rubber structure, a continuous an
said- valve chamberlm‘eans carried- by said valve
chamber wall positioriedfor reducing the effec-v
tive cross-sectional: area of said-opening in said
wall upon collapse‘v of said valve chamber wall
' and providing a passageway for air regardless of
the; collapse of said chamber wallysaid valve
formed inside and on the. bottom, portion‘, of said 140 chamber wall being" adapted to collapse upon sud- '
nular rib about ‘said ori?ce. and sp'aceditherefrom
rubber structure, aplurality of apertures: formed
through the wall of saidrubber: structure-inter
mediate saidribv and. said flange; the- total cross
sectional area‘ ofsaid ape-rturesbeingr such as to
den removal of substantial, air pressure on the _
other side of said. operating‘ Wall» from? said Valve
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