CA1063915A - Elastically deformable insert for a vehicle tire casing for support when the casing is deflated - Google Patents
Elastically deformable insert for a vehicle tire casing for support when the casing is deflatedInfo
- Publication number
- CA1063915A CA1063915A CA281,465A CA281465A CA1063915A CA 1063915 A CA1063915 A CA 1063915A CA 281465 A CA281465 A CA 281465A CA 1063915 A CA1063915 A CA 1063915A
- Authority
- CA
- Canada
- Prior art keywords
- tire
- elastically deformable
- hollow bodies
- closed hollow
- annular band
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C17/00—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor
- B60C17/01—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor utilising additional inflatable supports which become load-supporting in emergency
- B60C17/02—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor utilising additional inflatable supports which become load-supporting in emergency inflated or expanded in emergency only
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
- B60C17/00—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor
- B60C17/01—Tyres characterised by means enabling restricted operation in damaged or deflated condition; Accessories therefor utilising additional inflatable supports which become load-supporting in emergency
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Tires In General (AREA)
- Discharge Of Articles From Conveyors (AREA)
Abstract
AN ELASTICALLY DEFORMABLE INSERT FOR A
VEHICLE TIRE CASING FOR SUPPORT
WHEN THE CASING IS DEFLATED
Abstract of the Disclosure An elastically deformable member to be inserted in the cavity of a vehicle tire to support the tire if it is punctured and deflated. The insert member has at least one annular band, which, at atmospheric pressure, is in a stretched condition in the direction of its own circumferential development. A plurality of closed hollow bodies are connected to the radially external surface of the band and are aligned with one another for the entire develop-ment of the surface whereby the interfacings of the contiguous bodies are in contact with each other. The closed hollow bodies contain a gaseous fluid at a pressure above atmospheric pressure and not more than the tire inflation pressure. The tension on the band varies with variation in the inflation pressure.
VEHICLE TIRE CASING FOR SUPPORT
WHEN THE CASING IS DEFLATED
Abstract of the Disclosure An elastically deformable member to be inserted in the cavity of a vehicle tire to support the tire if it is punctured and deflated. The insert member has at least one annular band, which, at atmospheric pressure, is in a stretched condition in the direction of its own circumferential development. A plurality of closed hollow bodies are connected to the radially external surface of the band and are aligned with one another for the entire develop-ment of the surface whereby the interfacings of the contiguous bodies are in contact with each other. The closed hollow bodies contain a gaseous fluid at a pressure above atmospheric pressure and not more than the tire inflation pressure. The tension on the band varies with variation in the inflation pressure.
Description
~his :invention xelates gcnerally to a safety tire for a vehicle and, moLe par-ticularly, to a tube]ess tire having a casiny s and a structure disposed in the casing which adapts the tire -to continue to be serviceable if punctured.
" It has been proposed before to provide safety tires con-'Itaining a tube having the form of a toroidal ring which, upon in-!' flation, totally occupies the free space on the inner side of the ¦'casing. This ring is subdivided internall~ by means of radial jIwalls into numerous compartments each one independent of ihe other.
1l After the tube is placed in the tire casing each of the 1, ~compartments of the tube is inflated separately through its own alve. Each of the valves is connected to its own compartment and .
'to a main ~Jalve. The valves for the compartments are closed suc- !
l,cessively in order to guarantee an individual sealing for each com-!
, partment. Consequently, in case the tire should puncture, the ¦ i aforesaid tube will adequately support the tire for at least a i short distance to the nearest service station, even though the ¦,foreign body which caused the puncture should extend far er.ough jiinwardly to pierce the tube surface lying in contact with the ~- 20 ,~casing. In such cases, the foreign body would only penetrate the .-tube in a single compartment, causing only that compartment to be- , 'come deflated while leaving the remaining compartments of the tube ¦
~- ~ completely unaffected. Hence, these other compartments would still , be able to continue to function properly.
~lthough a tire constructed as described would appear to he ' completely satisfactory, it has not been entirely successful in practice.
Its yreatest drawbacks have been its undeniable complexity both, as re~ards the manufacture of the tube, as well as the difficulty in inserting the tube in the casing. Moreover, the weight of the tube because of its numerous valves frequently introduces an unbalanced condition in the tire which limits its performance.
Another type of safety tire has an inflatable struc-ture which defines two cavities when it is inserted in the casing, one on its inside and the other between it and the casing. Both of these cavities can be filled with air having the very same pressure, or even with air having different pressures. When a tire containing such a tube is punctured, the tube, according to its structure, can act in two different ways: in the first case it simply supports the deflated casing avoiding the complete squeezing of the casing between the road and the rim. Otherwise said tube is inflated at a higher pressure passing from a rest position, where -- as stated before -- it only partially occupies the casing cavity, to a working position, filling up completely the tire ca~ity and coming into contact with the internal surface of the casing in deflated condition so as to support it. Such a tube has not met with commercial success because, inter alia, it must have two or more layers of rubberized fabric covered with other further layers of rubber in order to guarantee ade~uate support for the deflated tire, and to furnish another thickness of material to avoid puncture of said tube by a nail or other penetrating object. Consequently the manufacture of such a structure would be very complex. If the tube moreover is to be inflated under a higher pressure as indicated above, ~uch higher pressure could not be provided automatically but could be obtained only with actual direct intervention on the part of the car driver to feed the pressurized air or gas into ~ _3_ ' ~063915 the structure once the tire is completely deflated.
It is an object of this invention to provide a safety tire structure which reliably converts a tubeless casing into a . .
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, -3a-l~ ~
i 1063915 "puncture-proof" tire ar.d has simple construction which adapts it for use in any tllbeless tire casing. Anotl~er object of th~ inven-tion is to provide a tube for insertion in a vehicle tire casing to adapt it for continued use,at least on a temporary basis if the casin~ is punctured,which can be easily mounted with the casing on I a vehicle wheel rim and can be used in the casing without signifi-¦Icantly impairing the behavior of the tire. Still another object ijf the inven,ion is to provide a vehicle tire of the tubeless type with a tube which will maintain the tire in running condition after;
the casing is punctured and will not interfere with the functioningl of the tire when it is inflated and used in normal service even at ! -¦high speeds. ¦
¦ Other objects will become apparent from the following des- ¦
cription with reference to the accompanying drawin~ wherein: i Figure 1 is a fragmentary perspective view of one embodiment of an elastically deformable structure provided by the inventior.; ~ i i ¦ Figure 2 is a section o~ a length of the structure of Figure ¦~1 in a circumferential plane; , I
1! Figure 3 represents a radial section of a portion o~ a tube-l -¦lless tire, of a portion of the rim and a portion of the elastically'~
deformable structure of Figures 1 and 2, during the mounting opera-~;tion o' the assembly; ¦
j Figures 4 and 5 represent, respectively in radial section j and in section according to the equatorial plane, the tire-rim j assembly comprising the elastically deformable structure under ,'normal service conditions; !~ -Figures 6 and 7 represent in cross-section and in section !
according to the equatorial plane, the assembly of Figure 4 with the elastically deformable structure in working condition.
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;, I ! -, The objects of the invention are accomplished by providing a member_of elasticalIy deformable material.suitable for being _ _ mounted together with the tire on a rim of a vehicle wheel with , the structure inserted in the tire casing and occupying a portion !
, of the ca~ity. The deformable member comprises at least one ..__ 1 Ijannular band which, at atmospheric pressure, is in a stretched ¦~condition in the direction of its own circum~erential development, ¦~ a plurality of closed hollow bodies connected to the radially !
¦external surface of the band and aligned, one with the other, - l ~throughout the entire development of the surface so that the interi jfacings of the contiguous bodies are in contact with one another, ¦the closed hollow bodies containing gaseous fluid havirlg a pressure higher than atmospheric pressure and at the most e~ual to the in- !
flation pressure of the tire, and means for varying the stretched condition of the band with variations in pressure acting from the outside on the elastically deformable member.
Preferably, the stretched condition of the annular band varies as the pressure surrounding the structure varies from atmos, ¦~pheric pressure to the value of the inflation pressure of the tire,~
i~so that the development of this band is between a maximum.value, !
I corresponding at least to the maximum development of the rim and a !
¦¦minimum value which is equal at least to the minimum development !
~iof the rim. i I In the present disclosure~ the term ~maximum developmentn ~
;50f the rim is intended to mean the development o~ the circumferenc¦
, corresponding to the extremity of the rim flange; and the term l ~"minimum development" is intended to mean the development corres-ponding to the base or base well circumference of the rim.
In particular, the closed hollow bodies are the means which$~.are able to vary the stretched condition of the annular band of ~s I
,, _5_ ' .
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' 1063915 the structure, in consequence Gf the ~ariations in th~ ambient ' pressure surrounding the structure.
In a ~referred embodimen~, the annular band has a width ' which is equal substantially to the axial distance between the ~ . .
' tire beads, when the tire is mounted on the rim.
!~ The closed hollow bodies, for expedience sake, are tubular i bodies the axial extension of which is equal at least to the !width of the annular band; they are disposed on this band at regu-~
! lar intervals from each other.
For the purpose of efficiently ~ulfilling their function ith respect to the annular band, and so as to be capable of sup- !
porting the tire, should it become accidentally-deflated (which ¦'function shall be dealt with further on in more detail) the walls I¦at least of the cl~sed hollow bodies, are made of elastically de-Iformable, air-impermeable material, which will ensure that the gas ¦
Ipressure contained inside is maintained as stable as possible with ,the passage of time. Preferably, these walls are made o~ a vul- ¦
!i canized elastomeric compound based on natural rubber or a synthe-ljtic rubber such as butyl rubber, either halogenated or not.
I! Preferably the closed hollow bodies form a single body with jthe annular bandi that is to say, the wall portion of each closed ~
jlhollow body in contact with the anr.ular band, consists of a length ~
iif the band. The latter, which as aforesaid, can be made of any ;
!1 elastically deformable material, is preferably constituted by an ' ~'air-impermeable elastomeric material as indicated above. , In order to ensure that during variations in the ambient '" pressure, the closed hollow bodies can perform their function as ',regards the annular band, so that the latter is able to vary its stretched condition, and hence, its development, appropriate ~, thicknesses are selected for the band and for the body walls respectively, and/or elongation modulus of the elastomeric compo~ds, appropriate thicknesses are ~ ¦
selected for the band and for the body walls respective'y, fro~
which the band and the bodies are composed. ~or instance, by em- .
ploying one single elas~omeric compound having a modulus of 0.128 I Kg/mm2 at elongation of 10%, the wall thickness of the bodies is i ¦,3mm, while the thickness of the band is 13mm. On the contrary, by ' ,adoptiny a sole value for the thickness of the body wall and of the!
~band, as equal to. 3mm, the elastomeric compound utilized for the !
body walls will have a modulus at elongation of 10% equal ~o 0.128 7 Kg/mm while the elastomeric compound utilized.for the annular.
¦band has a modulus at elongation of 10% equal to 6 Kg/mm2.
i The annular band of the structure at atmospherIc pressure ¦jhas a development egual at least to the maximum Aevelopment of the ~¦rim on which the structure is mounted. ¦ , The volume of the closed hollow bodies placed on the band, j ' that ic to say more specifically, their radial extension when at~
j~mospheric pressure surrounds them, is such that the entire struc-jiture in its radial section has a height between 60~ and 85% of the I :
¦,cavity of the casing to which it is destined. In addition, the , Iideal circumference circumscribing..the closed hollow bodies, has a . L
diameter which is either equal to, or does not exceed by more : than 10%, the internal diameter of the tire which is ¦,destined to receive the structure. ¦ ~ :
The number of closed hollow bodies containing pressurized l 3.gaseous fluid evidently varies according to the size of the tire to' .which the elastically deformable structure has been destined. , .
Taking into account that, in order to perform an efficient function . which shall be explained further on, the closed hollow bodies have to be in contact with each other and, at the same time, their , .
', ~ ,.
~ ! -7 \.
;volume has to be such as to allow for a space within the cavity o~ , .the tire casing on which the structure is mounted, these closea . hollow bodies will pr~ferably consist of a number between 8 and ' :
360.
According to an alternative embodiment of the present inven-~tion, the el,~stically deformable structure also comprises a second ~~annular band which is placed in contact with the radially outward !
¦Iportions of the closed hollow body wall; also this second ænnular ~band, under atmospheric pressure conditionsj is in a stre~ched ¦condition and it has a development which is equal at least to the ¦
.. ~ideal circumference circumscribing the said closed hollow bodies. ¦ .
. ~ Similarly to the first annular band, a~so the econd band.
can form a single body with the closed hollow bodies underlying it;¦
. lin other words, the radially outward portion of the wall of each ¦the closed hollow bodies consists of a length of.said second annu- j lar band. ¦
j It is evident that the aforesaid structure in elastica~ly : Ideformable material, has a very simpli~ied construction, and does not¦
: ,present any particular difficulty as to its manufacture. '~he closed .
jhollow bodies containing pressurized gaseous fluid can be obtained !
by molding, either along with the single or the two, annular bands l l or even apart from these bands, by employing any manufacturing pro- -¦ cess whatsoever known to technicians of the field, which is : suitable for obtaining hollow bodies containing pressurized gas, such as, for instance, by utilizing a pellet of a substance which ¦
ireleases gas through its decomposition with an increase in tempera-:ture.
¦ Inside each of the closed hollow bodies to be manufactured, , ~consti'cuted by two symmetrical halves, a pellet is inserted; after.
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, i~ ~
10639~5 the two half surface.s have been placed into contact together, the molding process takes place followed, as needed, by a curing treat-men~ of the ~ho]~ ~rticle if this should happcn to be of an elasto-meric material. t ~s an alternative, recourse can be taken to the process ,according to which the two symmetrical halves of all the hollow bodies either separately or with the single annular band or the two~
annular bands, are molded simultaneously in a series of cavities of the mold which is contained within a case, inio which is admitted !either air or nitrogen having their pressure value equal to the ¦! desired value for hollow bodies; there the halves are welded to-¦~gether and cured.
o matter which molding technique is followedf the first ¦annular band is formed inside the mold according to a diameter ! I
sligh~ly less than the minimum diameter of the rim onto which the ~ , I structure will have to be mounted. Once the structure is extracted ¦'from the mold and brought to atmospheric pressure, the closed ,Ihollow bodies containing pressurized fluid gas which were originally islightly spaced apart, one away from the other, now expand so that ' ,the facing wall portions of adjacent hollow bodies now come into j ) jcontact with each other and their cross-section, which was substan- i ¦¦tially circular, now becomes ovoidal. In the meanwhile, an action ¦ i ¦llof reciprocal repulsion is generated between these closed hollow ¦
bodies in contact with each other, thus giving rise to radial I
~forces which cause a further expansion of the closed hollow bodies i ,jin the outward direction, and the stretching of the underlying ,'annular band; so taking the latter to a development greater than that in the molding. In the imposed conditions of band thickness and of the closed hollow body wall thickness,of the gas pressure - ' 1~.
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"1063915 ' I
inside the bodies and/or of the modulus oE the elastolQeric com-pound selected for the annular band and the closed hollow bodies, the interna] develo~men~ of the stretc`ned annu]ar band is at least ;equal to the maximum external development of the rim flange to j which the structure is destined.
,~ If the structure also has a second annular band, it is ¦lmolded at a diameter equal to that of the ideal circumference cir- .
cumscribing the hollow bodies in -the mold. The modulus of the ! I
¦elastomeric compound and/or its thickness are selected so that the l ¦
~0 ,band will be in a stretched condition after expansion o~ the ! I
closed hollow bodies. j ¦
As said before, the elastically deformable structure is in-serted and mounted to~ether with a tubeless tire on a rim. It wil~ ~
support the tire if the tire becomes deflated. j ¦
, ~ The invention thus provides an assembly of a vehicle rim !
and a vehicle tire mounted Oll the rim and having a stru~ture of thé}
j ¦Itype described in the cavity of the tire casing disposed in such a ¦ ¦
I liway that the first annular band faces the rim. The part of the ' ¦
¦,tire cavity about the deformable ring contains air at inflation . 1-lipressure.
More particularly, the elastically deformable structureinserted in the tire-rim assembly under tire inflation pressure is !
jin a first position, where the stretching of the annular band i,facing the rim is reduced and it has a development equal at least i~to the minimum development of the rim, while the axially external j portions of the walls of each of the closed hollow bodies contracted by the inflation pressure lean a~ainst and are pushed towards the !~ radially external surface of the rim without necessarily touching ',the tire beads. In the working condition (that is to say, when the ., .
i, ~,, -10- , I
. - I
!' 1063915 " tire is punctured and the inflatiorl air has escaped) as a result of , the expansion of the hollow bodies caused by the pressure of the J
' flUiri contained therein, the aforesaid structure is able to move 'into a second position, according to which the stretch~ng condition ,of the annular band increases and the latter deforms according to ia greater development than that of the development of the first ¦Iposition, while the external surface of all the closed hollow bodies comes definitely into contact with the internal surface of !the casing which is underlying the tread. Should the structure also have the second annular band outside the closed hollow bodies, ¦Ithis band will co~e into contact with the internal surface of the ~
~casing. Hence, in the punctured condition of the tire (that is, ¦
when the tire is without inflation pressure) in the portion of the Itire which, during its rotation, is subjected to squeezing under j' ¦!load, t e hollow bodies will be compressed against the rim and willT
iicontemporaneously undergo an axial expansion which will take them 1 ~
!l into definite contact with the tire beads so as to guarantee the l i ~¦correct positioning of the tire on the rim flange even under a con-3 dition of drifting in the tire.
~: ! j The invention just described and also the action of the ¦~elastically deformable structure, which forms its main object, ~along with the advantages to be derived b~ its adoption,wili be- ¦
i,better understood with the aid of the attached drawing.
¦' A length of the elastically deformabl2 structure pro-vided 1, ~by the present invention in atmospheric pressure condition is illus-trated in a perspective view in Figure 1. The deformable structure 1~
'has an annular band 2 and a plurality of closed tubular bodies 3. ~ j Each one of the bodies 3 contains air at a pressure of 1.3 atm.
,, . I I
This structure is destined to be mounted together with a tubeless :' '' -11- !
.. ~ `, 1063915 ' I
tire, size 135 SR 12, on a rim having a maximum ai~meter e~ual to 339 mm with the annular band 2 in a stretched condition, accordir.g' to a di~meter equal to 3~5 ~, the width of the band being 70 mm, and with a thickness of 3.5 mm. Thir-ty-two closed tubular bodies ' are distr.ibuted at regular intervals along the whole surface of ~the larger diameter of the annular band 2. The w~lls of the bodies, ¦ as the annular band, are made of an elastomeric compound based on ¦vulcanized chlorobutyl rubber having a modulus E equal to 0.15 Kg/mm ; they have an axial extension of 85 mm. When expanded to the¦
j max'imum state, the thickness of the walls of these closed tubular bodies is equal to 1.5 mm.
A length of structure 1 is ill.ust-ated in Figure 2 in sec-,tion according to a circumferential plane. It is evident from Figure 2 how each closed tubular body 3 forms into one single body j I,together with the annular band 2, how the wall portions facing be- !
¦Itween the adjacent tubular bodies are in contact with one another, !
,and how by expansion at atmospheric pressure, the tubular bodies ~
¦assume an ovoidal section. I
, The elastically deformable structure 1, with the sealed iclos'ed tubular bodies containing pressurized air, has, as stated !
liabove~ its annular band in a stretched condition, according to a ~
¦Idevelopmen,' ~he ~iam~ter of which is greater than the maximIm de- ¦
¦Ivelopment of the rim. As a matter of fact, in constituting this ~
¦!structure according to any manufacturing process known per se, the ', jslongitudinal development of the annular band is selected according ' ito a length which is either equal to or preferably less than the ~!maximUm development of the rim onto which the structure has to be I
'mounted. But it must be ta~en into account tha~ once the structure.
is reali~ed and brought to atmospheric pressure between each of the ,,, '.
, 1063915 ~
tub~lar bodie~ ~, havincJ insid~ th~m a presc;ure, which in the given case illustrated by the figure~s, is 1.3 atm, there is produced an action of reci~-rocal rcpulsic)rl wllich results in radial force~
tYhich cause tlle stretched condition, i.e., the deformations of the I'annular band to the extent of a ~reater developmen~ than that of its own, until the maximum development of the rim is reached and , ¦lexc`eeded.
This leads to a first advantage in the operation of mounting ¦Ithe tubeless tire together with the structure on the ri~l, as is ~levident in Figure 3 In this figure there i5 represented in radial, ~section a portion of rim 6, a porticn of tire 7 and a portion 8 of ~ i the elastically deformable structure 1 at the time of mounting. It~ !
¦!is noted that this ~tructure presses against the inside wall of the ¦!tire casing 7 which underlies the tread 9 so as to leave the zone jllcorr~espcnding to the tire beads 10 completely free. In such ~ way,' !I the mounting of ~he tire on the rim takes place without any impedi-I,ment on the part of the introduced structure and without there l I
¦~being any need for manual or mechanical intervention, for fixing ¦ the structure into the above-indicated position.
¦ In Figures 4 and 5, there is represented, in a radial section and in a section along the equatorial plane, respectively, a seg-jlment of a tirQ-rim assembly containing the elastical7y deformab e ~structure under normal service conditions, i.e., where the pressure llin the cavity about the insert is higher than atmospheric pressure~
As can be seen, once the pressurized air has been admitted into -i! the tire, which in this case is of 2 atm, the air pressure acts on each body 3 eliminating the repulsion forces between the inter-' facin~s of the bodies and consequently, uniformly reducing the volume of each closed tubular body.
" ,:
' 13 Hence~ the stretched condition of the annular band tend~ to be annulled and the band returns practically to the same dimen~ions of development as dur$ng molding.
In case this developm~nt should be equal to the mini-mum development of the rim, the band comes into contact with the base well 4 of the rim 6.
But preferably, this development in the mold is designed so as to have a circumference less than the minimum circumference of the rim. In thi~ way, the band, because of the action of the inflation pressure exerted over the closed tubular bodies 3, in tending to regain its original development dimensions, abuts against the base well 4 of the rim, still keeping in its position an important tension residue. In this way, even under tlrs service conditions at the highest speeds, thanks to the residual elastic tension of the band and due to the direct action of the pressure which holds the structure against the rim, the structure does not shift from its posi-tion and no unbalance occurs which could negatively affect the -.
performance of the tire.
For facilitating this action of the closed tubular bodies by means of inflated air-pressure, a hole (not repre-sented in the figure) is provided on the rim base. This hole, although closed both at the time oftLP~ lnflation as well as during the normal functioning of thetirer is opened for per-mitting air, which may have remained entrapped between the rim base and the annular band 2, to escape.
In Figure 6 there is represented in radial section the as~embly of Figure 4, i.e., the rim 6, ~he tire 7 and the ; ela~tically deformable structure. For showing the working con-dition of structure l when the tire is punctured and deflated, the whole assembly is shown. More particularly, the rotation axi~ A-A' divides the lo~er part B of the assembl~ correspondinc3 to the part of the , tire which is cyclically squee~ed against the grour,d under load, from the upper part C o~ the assembly.
Once there occurs an accidental puncture to the tire 7, the , S inflation air contained in the cavity 12 (see Figure 4) escapes ~;through the puncture and hence, the original pressure on the clos~d tubular bodies 8 of the structure 1 is reduced to zero. As can be seen in Figure 6, as a consequence of the diminishing of the infla-I`tion pressure, the tubular bodies activated by their own internal Ipressure, expand, and thence, similar to what occurs in the mount- ¦
ing phase illustrated in Figure 3, tends to regain contact with thei !tire internal surface 9 which underlies the tread, sub-ec'cing the ¦ iiannular band 2 to being stretched and deforming it according to a ¦
greater development than the one corresponding to the first posi-tion and tending to a maximum value, correspondin~ to the value ¦'which it had in the mounting stage. Obviously, as the tire rolls, ~it is squeezed in the zone which comes into contact with the ground ! under the load of the vehicle. However, the tire is efficiently ¦ ! supported in this state by the radially external surface o~ the ¦~tubular bodies 8 and at the same time even the tire beaas 10 remain ¦ !Ifixed in their position on the rim.
In Figure 7 the structure 1 is shown in a section along the equatorial plane to show the condition of the closed cylindrical j,bodies ~ along their entire circumferential development. In parti-l I cular, it can be noted that the cylindrical bodies 8' next to the ¦
casing touching the ground are expanded to dimensions larger than ' in Figure 5 and are pressed in against the internal surface 9 I underlying the tread and the annular band por-tion is against the - I corresponding par-t of the base well of the rim 4. As one graduallyi ,! -15-;:
1063915 i 1 moves a~ay from the squ~ezcd tire zorle towards the zone diametri- ~ ¦
cally opposite it, the closed cylindric~l bodies 8" ~ecome more , liberally subject to the act:ion of the;.r own internal pressure, and hence, owiny to their ur.opposed expansion, they put the under-ly.ing )~and into a stretched condition and they gradually pull it away from the base well of the rim. This stage of operatio~ is ,"repeated cyclically as the tire rolls along while the vehicle ; ~'driver is in a position to be warned if a puncture has occurred to ¦
: ¦,the tire, he may continue driviny the vehicle, even for long dis- I
lltances, without causing any further damage to the tire. In order l~ .
I llto facilitate the movements of the elastically deformable struc~ure j within the tire cavity, the latter may contain a conventional lubriL
lcant. It is to be noted that even in the case of a tire having be_ llcome punctured owing to a sharp shaped ~orei~n body having a length j,such as to penetrate right inside it, the elastically deformable . ¦'structure which forms the object of the present invention is non- l i ; !¦ theless still able to carry on functioning in an efficient manner. !
As a matter of fact, in a case such as the above, the foreign ~body can only damage one, or at most two, of the closed hollow ¦ 20 ~,bodies which, by expanding, have come into contact with the internal,surface of the tire, thus preventing any .relative movemen~ between the casing and the structure. But this occurrence does not prevent' '-the remaining closed hollow bodies of the structure from continuing¦
~to act as a tire support.
, The elastically deformable structure which forms the object ¦
of this present invention comprising, as it has already been statea, ~closed hollow bodies containing a pressurized gaseous fluid, can be ~produced and then stored even for long per.iods of time, be~ore being utilized ¦
i; , , Por th:is purpose, bcsides ~)e;ncJ con;Lituted at least as far , as the wal.~s of these closed hollow bodics are concerned, ~y elas--tically defo.rmable mat:erial havincJ a hicJh air-impermeability, they can also be sto.red to advantage in a container or box made of metal~
or of plastic material designed in such a way as to produce, on being closed, an internal pressure equal to that o the gaseous fluid contained inside the closed hollow bodies of the elastically !
¦deformable structure enclosed in the container. In this way, if llthe structure remains in the container, it does not cause the ¦
¦Iclosed hollow bodies to become deflated. As a matter of fact, . llowing to the equilibrium between the pressure inside the container ¦
¦land the pressure inside the closed hollow bo~ies (as it happens whe ¦Ithe hollow bodies are on the inside of the tire under operating ~,condi.tions), there is no gas diffusion towards the outside. Should ~'~he px.essure within the container exceea that inside the close~
: ~'hollow bodies of the structure, the inversion of the phenomena can , ! even be obtained with the diffusion towards the inside of the arti-cle, and the consequent "regeneration" of the deflated closed ¦
! hollow bodies. ~ I
' A container of the type described above, is disclosed in -¦ ',.Italian Patent No. 445.260 by the same applicant. ~, It is to be understood that the present invention is not , Iilimited to what is indicated above, but that. it includes any other !
~ ¦ alternative embodiment derivi.ng from the above-indicated inventive !
., 25 , principle, for instance, providing one or two annular bands in con-¦
'tact with the axially external portions of the closed hollow bodies of the structure, having a width and development such as not to oppose the variatio~s of their dimensions during the operation of the strueture itself.
-17- ~
" , ~', ,
" It has been proposed before to provide safety tires con-'Itaining a tube having the form of a toroidal ring which, upon in-!' flation, totally occupies the free space on the inner side of the ¦'casing. This ring is subdivided internall~ by means of radial jIwalls into numerous compartments each one independent of ihe other.
1l After the tube is placed in the tire casing each of the 1, ~compartments of the tube is inflated separately through its own alve. Each of the valves is connected to its own compartment and .
'to a main ~Jalve. The valves for the compartments are closed suc- !
l,cessively in order to guarantee an individual sealing for each com-!
, partment. Consequently, in case the tire should puncture, the ¦ i aforesaid tube will adequately support the tire for at least a i short distance to the nearest service station, even though the ¦,foreign body which caused the puncture should extend far er.ough jiinwardly to pierce the tube surface lying in contact with the ~- 20 ,~casing. In such cases, the foreign body would only penetrate the .-tube in a single compartment, causing only that compartment to be- , 'come deflated while leaving the remaining compartments of the tube ¦
~- ~ completely unaffected. Hence, these other compartments would still , be able to continue to function properly.
~lthough a tire constructed as described would appear to he ' completely satisfactory, it has not been entirely successful in practice.
Its yreatest drawbacks have been its undeniable complexity both, as re~ards the manufacture of the tube, as well as the difficulty in inserting the tube in the casing. Moreover, the weight of the tube because of its numerous valves frequently introduces an unbalanced condition in the tire which limits its performance.
Another type of safety tire has an inflatable struc-ture which defines two cavities when it is inserted in the casing, one on its inside and the other between it and the casing. Both of these cavities can be filled with air having the very same pressure, or even with air having different pressures. When a tire containing such a tube is punctured, the tube, according to its structure, can act in two different ways: in the first case it simply supports the deflated casing avoiding the complete squeezing of the casing between the road and the rim. Otherwise said tube is inflated at a higher pressure passing from a rest position, where -- as stated before -- it only partially occupies the casing cavity, to a working position, filling up completely the tire ca~ity and coming into contact with the internal surface of the casing in deflated condition so as to support it. Such a tube has not met with commercial success because, inter alia, it must have two or more layers of rubberized fabric covered with other further layers of rubber in order to guarantee ade~uate support for the deflated tire, and to furnish another thickness of material to avoid puncture of said tube by a nail or other penetrating object. Consequently the manufacture of such a structure would be very complex. If the tube moreover is to be inflated under a higher pressure as indicated above, ~uch higher pressure could not be provided automatically but could be obtained only with actual direct intervention on the part of the car driver to feed the pressurized air or gas into ~ _3_ ' ~063915 the structure once the tire is completely deflated.
It is an object of this invention to provide a safety tire structure which reliably converts a tubeless casing into a . .
. .
, -3a-l~ ~
i 1063915 "puncture-proof" tire ar.d has simple construction which adapts it for use in any tllbeless tire casing. Anotl~er object of th~ inven-tion is to provide a tube for insertion in a vehicle tire casing to adapt it for continued use,at least on a temporary basis if the casin~ is punctured,which can be easily mounted with the casing on I a vehicle wheel rim and can be used in the casing without signifi-¦Icantly impairing the behavior of the tire. Still another object ijf the inven,ion is to provide a vehicle tire of the tubeless type with a tube which will maintain the tire in running condition after;
the casing is punctured and will not interfere with the functioningl of the tire when it is inflated and used in normal service even at ! -¦high speeds. ¦
¦ Other objects will become apparent from the following des- ¦
cription with reference to the accompanying drawin~ wherein: i Figure 1 is a fragmentary perspective view of one embodiment of an elastically deformable structure provided by the inventior.; ~ i i ¦ Figure 2 is a section o~ a length of the structure of Figure ¦~1 in a circumferential plane; , I
1! Figure 3 represents a radial section of a portion o~ a tube-l -¦lless tire, of a portion of the rim and a portion of the elastically'~
deformable structure of Figures 1 and 2, during the mounting opera-~;tion o' the assembly; ¦
j Figures 4 and 5 represent, respectively in radial section j and in section according to the equatorial plane, the tire-rim j assembly comprising the elastically deformable structure under ,'normal service conditions; !~ -Figures 6 and 7 represent in cross-section and in section !
according to the equatorial plane, the assembly of Figure 4 with the elastically deformable structure in working condition.
, .
"
;, I ! -, The objects of the invention are accomplished by providing a member_of elasticalIy deformable material.suitable for being _ _ mounted together with the tire on a rim of a vehicle wheel with , the structure inserted in the tire casing and occupying a portion !
, of the ca~ity. The deformable member comprises at least one ..__ 1 Ijannular band which, at atmospheric pressure, is in a stretched ¦~condition in the direction of its own circum~erential development, ¦~ a plurality of closed hollow bodies connected to the radially !
¦external surface of the band and aligned, one with the other, - l ~throughout the entire development of the surface so that the interi jfacings of the contiguous bodies are in contact with one another, ¦the closed hollow bodies containing gaseous fluid havirlg a pressure higher than atmospheric pressure and at the most e~ual to the in- !
flation pressure of the tire, and means for varying the stretched condition of the band with variations in pressure acting from the outside on the elastically deformable member.
Preferably, the stretched condition of the annular band varies as the pressure surrounding the structure varies from atmos, ¦~pheric pressure to the value of the inflation pressure of the tire,~
i~so that the development of this band is between a maximum.value, !
I corresponding at least to the maximum development of the rim and a !
¦¦minimum value which is equal at least to the minimum development !
~iof the rim. i I In the present disclosure~ the term ~maximum developmentn ~
;50f the rim is intended to mean the development o~ the circumferenc¦
, corresponding to the extremity of the rim flange; and the term l ~"minimum development" is intended to mean the development corres-ponding to the base or base well circumference of the rim.
In particular, the closed hollow bodies are the means which$~.are able to vary the stretched condition of the annular band of ~s I
,, _5_ ' .
, , ~ ~,,~ '.
. .
' 1063915 the structure, in consequence Gf the ~ariations in th~ ambient ' pressure surrounding the structure.
In a ~referred embodimen~, the annular band has a width ' which is equal substantially to the axial distance between the ~ . .
' tire beads, when the tire is mounted on the rim.
!~ The closed hollow bodies, for expedience sake, are tubular i bodies the axial extension of which is equal at least to the !width of the annular band; they are disposed on this band at regu-~
! lar intervals from each other.
For the purpose of efficiently ~ulfilling their function ith respect to the annular band, and so as to be capable of sup- !
porting the tire, should it become accidentally-deflated (which ¦'function shall be dealt with further on in more detail) the walls I¦at least of the cl~sed hollow bodies, are made of elastically de-Iformable, air-impermeable material, which will ensure that the gas ¦
Ipressure contained inside is maintained as stable as possible with ,the passage of time. Preferably, these walls are made o~ a vul- ¦
!i canized elastomeric compound based on natural rubber or a synthe-ljtic rubber such as butyl rubber, either halogenated or not.
I! Preferably the closed hollow bodies form a single body with jthe annular bandi that is to say, the wall portion of each closed ~
jlhollow body in contact with the anr.ular band, consists of a length ~
iif the band. The latter, which as aforesaid, can be made of any ;
!1 elastically deformable material, is preferably constituted by an ' ~'air-impermeable elastomeric material as indicated above. , In order to ensure that during variations in the ambient '" pressure, the closed hollow bodies can perform their function as ',regards the annular band, so that the latter is able to vary its stretched condition, and hence, its development, appropriate ~, thicknesses are selected for the band and for the body walls respectively, and/or elongation modulus of the elastomeric compo~ds, appropriate thicknesses are ~ ¦
selected for the band and for the body walls respective'y, fro~
which the band and the bodies are composed. ~or instance, by em- .
ploying one single elas~omeric compound having a modulus of 0.128 I Kg/mm2 at elongation of 10%, the wall thickness of the bodies is i ¦,3mm, while the thickness of the band is 13mm. On the contrary, by ' ,adoptiny a sole value for the thickness of the body wall and of the!
~band, as equal to. 3mm, the elastomeric compound utilized for the !
body walls will have a modulus at elongation of 10% equal ~o 0.128 7 Kg/mm while the elastomeric compound utilized.for the annular.
¦band has a modulus at elongation of 10% equal to 6 Kg/mm2.
i The annular band of the structure at atmospherIc pressure ¦jhas a development egual at least to the maximum Aevelopment of the ~¦rim on which the structure is mounted. ¦ , The volume of the closed hollow bodies placed on the band, j ' that ic to say more specifically, their radial extension when at~
j~mospheric pressure surrounds them, is such that the entire struc-jiture in its radial section has a height between 60~ and 85% of the I :
¦,cavity of the casing to which it is destined. In addition, the , Iideal circumference circumscribing..the closed hollow bodies, has a . L
diameter which is either equal to, or does not exceed by more : than 10%, the internal diameter of the tire which is ¦,destined to receive the structure. ¦ ~ :
The number of closed hollow bodies containing pressurized l 3.gaseous fluid evidently varies according to the size of the tire to' .which the elastically deformable structure has been destined. , .
Taking into account that, in order to perform an efficient function . which shall be explained further on, the closed hollow bodies have to be in contact with each other and, at the same time, their , .
', ~ ,.
~ ! -7 \.
;volume has to be such as to allow for a space within the cavity o~ , .the tire casing on which the structure is mounted, these closea . hollow bodies will pr~ferably consist of a number between 8 and ' :
360.
According to an alternative embodiment of the present inven-~tion, the el,~stically deformable structure also comprises a second ~~annular band which is placed in contact with the radially outward !
¦Iportions of the closed hollow body wall; also this second ænnular ~band, under atmospheric pressure conditionsj is in a stre~ched ¦condition and it has a development which is equal at least to the ¦
.. ~ideal circumference circumscribing the said closed hollow bodies. ¦ .
. ~ Similarly to the first annular band, a~so the econd band.
can form a single body with the closed hollow bodies underlying it;¦
. lin other words, the radially outward portion of the wall of each ¦the closed hollow bodies consists of a length of.said second annu- j lar band. ¦
j It is evident that the aforesaid structure in elastica~ly : Ideformable material, has a very simpli~ied construction, and does not¦
: ,present any particular difficulty as to its manufacture. '~he closed .
jhollow bodies containing pressurized gaseous fluid can be obtained !
by molding, either along with the single or the two, annular bands l l or even apart from these bands, by employing any manufacturing pro- -¦ cess whatsoever known to technicians of the field, which is : suitable for obtaining hollow bodies containing pressurized gas, such as, for instance, by utilizing a pellet of a substance which ¦
ireleases gas through its decomposition with an increase in tempera-:ture.
¦ Inside each of the closed hollow bodies to be manufactured, , ~consti'cuted by two symmetrical halves, a pellet is inserted; after.
'.
, i~ ~
10639~5 the two half surface.s have been placed into contact together, the molding process takes place followed, as needed, by a curing treat-men~ of the ~ho]~ ~rticle if this should happcn to be of an elasto-meric material. t ~s an alternative, recourse can be taken to the process ,according to which the two symmetrical halves of all the hollow bodies either separately or with the single annular band or the two~
annular bands, are molded simultaneously in a series of cavities of the mold which is contained within a case, inio which is admitted !either air or nitrogen having their pressure value equal to the ¦! desired value for hollow bodies; there the halves are welded to-¦~gether and cured.
o matter which molding technique is followedf the first ¦annular band is formed inside the mold according to a diameter ! I
sligh~ly less than the minimum diameter of the rim onto which the ~ , I structure will have to be mounted. Once the structure is extracted ¦'from the mold and brought to atmospheric pressure, the closed ,Ihollow bodies containing pressurized fluid gas which were originally islightly spaced apart, one away from the other, now expand so that ' ,the facing wall portions of adjacent hollow bodies now come into j ) jcontact with each other and their cross-section, which was substan- i ¦¦tially circular, now becomes ovoidal. In the meanwhile, an action ¦ i ¦llof reciprocal repulsion is generated between these closed hollow ¦
bodies in contact with each other, thus giving rise to radial I
~forces which cause a further expansion of the closed hollow bodies i ,jin the outward direction, and the stretching of the underlying ,'annular band; so taking the latter to a development greater than that in the molding. In the imposed conditions of band thickness and of the closed hollow body wall thickness,of the gas pressure - ' 1~.
,'' \ .
"1063915 ' I
inside the bodies and/or of the modulus oE the elastolQeric com-pound selected for the annular band and the closed hollow bodies, the interna] develo~men~ of the stretc`ned annu]ar band is at least ;equal to the maximum external development of the rim flange to j which the structure is destined.
,~ If the structure also has a second annular band, it is ¦lmolded at a diameter equal to that of the ideal circumference cir- .
cumscribing the hollow bodies in -the mold. The modulus of the ! I
¦elastomeric compound and/or its thickness are selected so that the l ¦
~0 ,band will be in a stretched condition after expansion o~ the ! I
closed hollow bodies. j ¦
As said before, the elastically deformable structure is in-serted and mounted to~ether with a tubeless tire on a rim. It wil~ ~
support the tire if the tire becomes deflated. j ¦
, ~ The invention thus provides an assembly of a vehicle rim !
and a vehicle tire mounted Oll the rim and having a stru~ture of thé}
j ¦Itype described in the cavity of the tire casing disposed in such a ¦ ¦
I liway that the first annular band faces the rim. The part of the ' ¦
¦,tire cavity about the deformable ring contains air at inflation . 1-lipressure.
More particularly, the elastically deformable structureinserted in the tire-rim assembly under tire inflation pressure is !
jin a first position, where the stretching of the annular band i,facing the rim is reduced and it has a development equal at least i~to the minimum development of the rim, while the axially external j portions of the walls of each of the closed hollow bodies contracted by the inflation pressure lean a~ainst and are pushed towards the !~ radially external surface of the rim without necessarily touching ',the tire beads. In the working condition (that is to say, when the ., .
i, ~,, -10- , I
. - I
!' 1063915 " tire is punctured and the inflatiorl air has escaped) as a result of , the expansion of the hollow bodies caused by the pressure of the J
' flUiri contained therein, the aforesaid structure is able to move 'into a second position, according to which the stretch~ng condition ,of the annular band increases and the latter deforms according to ia greater development than that of the development of the first ¦Iposition, while the external surface of all the closed hollow bodies comes definitely into contact with the internal surface of !the casing which is underlying the tread. Should the structure also have the second annular band outside the closed hollow bodies, ¦Ithis band will co~e into contact with the internal surface of the ~
~casing. Hence, in the punctured condition of the tire (that is, ¦
when the tire is without inflation pressure) in the portion of the Itire which, during its rotation, is subjected to squeezing under j' ¦!load, t e hollow bodies will be compressed against the rim and willT
iicontemporaneously undergo an axial expansion which will take them 1 ~
!l into definite contact with the tire beads so as to guarantee the l i ~¦correct positioning of the tire on the rim flange even under a con-3 dition of drifting in the tire.
~: ! j The invention just described and also the action of the ¦~elastically deformable structure, which forms its main object, ~along with the advantages to be derived b~ its adoption,wili be- ¦
i,better understood with the aid of the attached drawing.
¦' A length of the elastically deformabl2 structure pro-vided 1, ~by the present invention in atmospheric pressure condition is illus-trated in a perspective view in Figure 1. The deformable structure 1~
'has an annular band 2 and a plurality of closed tubular bodies 3. ~ j Each one of the bodies 3 contains air at a pressure of 1.3 atm.
,, . I I
This structure is destined to be mounted together with a tubeless :' '' -11- !
.. ~ `, 1063915 ' I
tire, size 135 SR 12, on a rim having a maximum ai~meter e~ual to 339 mm with the annular band 2 in a stretched condition, accordir.g' to a di~meter equal to 3~5 ~, the width of the band being 70 mm, and with a thickness of 3.5 mm. Thir-ty-two closed tubular bodies ' are distr.ibuted at regular intervals along the whole surface of ~the larger diameter of the annular band 2. The w~lls of the bodies, ¦ as the annular band, are made of an elastomeric compound based on ¦vulcanized chlorobutyl rubber having a modulus E equal to 0.15 Kg/mm ; they have an axial extension of 85 mm. When expanded to the¦
j max'imum state, the thickness of the walls of these closed tubular bodies is equal to 1.5 mm.
A length of structure 1 is ill.ust-ated in Figure 2 in sec-,tion according to a circumferential plane. It is evident from Figure 2 how each closed tubular body 3 forms into one single body j I,together with the annular band 2, how the wall portions facing be- !
¦Itween the adjacent tubular bodies are in contact with one another, !
,and how by expansion at atmospheric pressure, the tubular bodies ~
¦assume an ovoidal section. I
, The elastically deformable structure 1, with the sealed iclos'ed tubular bodies containing pressurized air, has, as stated !
liabove~ its annular band in a stretched condition, according to a ~
¦Idevelopmen,' ~he ~iam~ter of which is greater than the maximIm de- ¦
¦Ivelopment of the rim. As a matter of fact, in constituting this ~
¦!structure according to any manufacturing process known per se, the ', jslongitudinal development of the annular band is selected according ' ito a length which is either equal to or preferably less than the ~!maximUm development of the rim onto which the structure has to be I
'mounted. But it must be ta~en into account tha~ once the structure.
is reali~ed and brought to atmospheric pressure between each of the ,,, '.
, 1063915 ~
tub~lar bodie~ ~, havincJ insid~ th~m a presc;ure, which in the given case illustrated by the figure~s, is 1.3 atm, there is produced an action of reci~-rocal rcpulsic)rl wllich results in radial force~
tYhich cause tlle stretched condition, i.e., the deformations of the I'annular band to the extent of a ~reater developmen~ than that of its own, until the maximum development of the rim is reached and , ¦lexc`eeded.
This leads to a first advantage in the operation of mounting ¦Ithe tubeless tire together with the structure on the ri~l, as is ~levident in Figure 3 In this figure there i5 represented in radial, ~section a portion of rim 6, a porticn of tire 7 and a portion 8 of ~ i the elastically deformable structure 1 at the time of mounting. It~ !
¦!is noted that this ~tructure presses against the inside wall of the ¦!tire casing 7 which underlies the tread 9 so as to leave the zone jllcorr~espcnding to the tire beads 10 completely free. In such ~ way,' !I the mounting of ~he tire on the rim takes place without any impedi-I,ment on the part of the introduced structure and without there l I
¦~being any need for manual or mechanical intervention, for fixing ¦ the structure into the above-indicated position.
¦ In Figures 4 and 5, there is represented, in a radial section and in a section along the equatorial plane, respectively, a seg-jlment of a tirQ-rim assembly containing the elastical7y deformab e ~structure under normal service conditions, i.e., where the pressure llin the cavity about the insert is higher than atmospheric pressure~
As can be seen, once the pressurized air has been admitted into -i! the tire, which in this case is of 2 atm, the air pressure acts on each body 3 eliminating the repulsion forces between the inter-' facin~s of the bodies and consequently, uniformly reducing the volume of each closed tubular body.
" ,:
' 13 Hence~ the stretched condition of the annular band tend~ to be annulled and the band returns practically to the same dimen~ions of development as dur$ng molding.
In case this developm~nt should be equal to the mini-mum development of the rim, the band comes into contact with the base well 4 of the rim 6.
But preferably, this development in the mold is designed so as to have a circumference less than the minimum circumference of the rim. In thi~ way, the band, because of the action of the inflation pressure exerted over the closed tubular bodies 3, in tending to regain its original development dimensions, abuts against the base well 4 of the rim, still keeping in its position an important tension residue. In this way, even under tlrs service conditions at the highest speeds, thanks to the residual elastic tension of the band and due to the direct action of the pressure which holds the structure against the rim, the structure does not shift from its posi-tion and no unbalance occurs which could negatively affect the -.
performance of the tire.
For facilitating this action of the closed tubular bodies by means of inflated air-pressure, a hole (not repre-sented in the figure) is provided on the rim base. This hole, although closed both at the time oftLP~ lnflation as well as during the normal functioning of thetirer is opened for per-mitting air, which may have remained entrapped between the rim base and the annular band 2, to escape.
In Figure 6 there is represented in radial section the as~embly of Figure 4, i.e., the rim 6, ~he tire 7 and the ; ela~tically deformable structure. For showing the working con-dition of structure l when the tire is punctured and deflated, the whole assembly is shown. More particularly, the rotation axi~ A-A' divides the lo~er part B of the assembl~ correspondinc3 to the part of the , tire which is cyclically squee~ed against the grour,d under load, from the upper part C o~ the assembly.
Once there occurs an accidental puncture to the tire 7, the , S inflation air contained in the cavity 12 (see Figure 4) escapes ~;through the puncture and hence, the original pressure on the clos~d tubular bodies 8 of the structure 1 is reduced to zero. As can be seen in Figure 6, as a consequence of the diminishing of the infla-I`tion pressure, the tubular bodies activated by their own internal Ipressure, expand, and thence, similar to what occurs in the mount- ¦
ing phase illustrated in Figure 3, tends to regain contact with thei !tire internal surface 9 which underlies the tread, sub-ec'cing the ¦ iiannular band 2 to being stretched and deforming it according to a ¦
greater development than the one corresponding to the first posi-tion and tending to a maximum value, correspondin~ to the value ¦'which it had in the mounting stage. Obviously, as the tire rolls, ~it is squeezed in the zone which comes into contact with the ground ! under the load of the vehicle. However, the tire is efficiently ¦ ! supported in this state by the radially external surface o~ the ¦~tubular bodies 8 and at the same time even the tire beaas 10 remain ¦ !Ifixed in their position on the rim.
In Figure 7 the structure 1 is shown in a section along the equatorial plane to show the condition of the closed cylindrical j,bodies ~ along their entire circumferential development. In parti-l I cular, it can be noted that the cylindrical bodies 8' next to the ¦
casing touching the ground are expanded to dimensions larger than ' in Figure 5 and are pressed in against the internal surface 9 I underlying the tread and the annular band por-tion is against the - I corresponding par-t of the base well of the rim 4. As one graduallyi ,! -15-;:
1063915 i 1 moves a~ay from the squ~ezcd tire zorle towards the zone diametri- ~ ¦
cally opposite it, the closed cylindric~l bodies 8" ~ecome more , liberally subject to the act:ion of the;.r own internal pressure, and hence, owiny to their ur.opposed expansion, they put the under-ly.ing )~and into a stretched condition and they gradually pull it away from the base well of the rim. This stage of operatio~ is ,"repeated cyclically as the tire rolls along while the vehicle ; ~'driver is in a position to be warned if a puncture has occurred to ¦
: ¦,the tire, he may continue driviny the vehicle, even for long dis- I
lltances, without causing any further damage to the tire. In order l~ .
I llto facilitate the movements of the elastically deformable struc~ure j within the tire cavity, the latter may contain a conventional lubriL
lcant. It is to be noted that even in the case of a tire having be_ llcome punctured owing to a sharp shaped ~orei~n body having a length j,such as to penetrate right inside it, the elastically deformable . ¦'structure which forms the object of the present invention is non- l i ; !¦ theless still able to carry on functioning in an efficient manner. !
As a matter of fact, in a case such as the above, the foreign ~body can only damage one, or at most two, of the closed hollow ¦ 20 ~,bodies which, by expanding, have come into contact with the internal,surface of the tire, thus preventing any .relative movemen~ between the casing and the structure. But this occurrence does not prevent' '-the remaining closed hollow bodies of the structure from continuing¦
~to act as a tire support.
, The elastically deformable structure which forms the object ¦
of this present invention comprising, as it has already been statea, ~closed hollow bodies containing a pressurized gaseous fluid, can be ~produced and then stored even for long per.iods of time, be~ore being utilized ¦
i; , , Por th:is purpose, bcsides ~)e;ncJ con;Lituted at least as far , as the wal.~s of these closed hollow bodics are concerned, ~y elas--tically defo.rmable mat:erial havincJ a hicJh air-impermeability, they can also be sto.red to advantage in a container or box made of metal~
or of plastic material designed in such a way as to produce, on being closed, an internal pressure equal to that o the gaseous fluid contained inside the closed hollow bodies of the elastically !
¦deformable structure enclosed in the container. In this way, if llthe structure remains in the container, it does not cause the ¦
¦Iclosed hollow bodies to become deflated. As a matter of fact, . llowing to the equilibrium between the pressure inside the container ¦
¦land the pressure inside the closed hollow bo~ies (as it happens whe ¦Ithe hollow bodies are on the inside of the tire under operating ~,condi.tions), there is no gas diffusion towards the outside. Should ~'~he px.essure within the container exceea that inside the close~
: ~'hollow bodies of the structure, the inversion of the phenomena can , ! even be obtained with the diffusion towards the inside of the arti-cle, and the consequent "regeneration" of the deflated closed ¦
! hollow bodies. ~ I
' A container of the type described above, is disclosed in -¦ ',.Italian Patent No. 445.260 by the same applicant. ~, It is to be understood that the present invention is not , Iilimited to what is indicated above, but that. it includes any other !
~ ¦ alternative embodiment derivi.ng from the above-indicated inventive !
., 25 , principle, for instance, providing one or two annular bands in con-¦
'tact with the axially external portions of the closed hollow bodies of the structure, having a width and development such as not to oppose the variatio~s of their dimensions during the operation of the strueture itself.
-17- ~
" , ~', ,
Claims (17)
1. An elastically deformable member adapted to be inserted in the cavity of a vehicle tire and partially fill the cavity, said member comprising at least one annular band, which, at atmospheric pressure, is in a stretched condition in the direction of its own circumferential development, a plurality of closed hollow bodies connected to the radially external surface of said band and aligned with one another for the entire development of said surface, whereby the interfacings of the contiguous bodies are in contact with each other, said closed hollow bodies containing a gaseous fluid at a pressure above atmospheric pressure and not more than the tire inflation pressure, and means for varying the stretched condition of said band with variation in pressure acting from the outside on said elastically deformable member.
2. The member of Claim 1 wherein the stretched condition of said annular band varies with variation in the pressure surrounding the said member from atmospheric pressure to the tire inflation pressure, whereby the development of said band is between a maximum value, corresponding at least to the maximum value of said rim development and a minimum value which is at least equal to the minimum value of said rim development.
3. The elastically deformable member of Claim 1 wherein the said closed hollow bodies are the means for varying the stretched condition of said annular band with variation in the pressure surrounding the structure.
4. The elastically deformable member of Claim 1 wherein said annular band has a width which is at least equal to the distance between the beads of a tire mounted on its rim.
5. The elastically deformable member of Claim 1 wherein said closed hollow bodies are tubular bodies, the axial extensions of which are at least equal to the width of the said annular band.
6. The elastically deformable member of Claim 1 wherein said closed hollow bodies are disposed on said annular band at regular intervals.
7. The elastically deformable member of Claim 1 wherein at least the walls of said closed hollow bodies are of an air-impermeable elastically deformable material.
8. The elastically deformable member of Claim 7 wherein at least the walls of said closed hollow bodies are of a vulcanized elastomeric rubber composition.
9. The elastically deformable member of Claim 1 wherein said walls when expanded under the action of the pressure inside the hollow bodies has a thickness between 0.3 and 2.5mm, the thickness of said annular band is between 2 and 13mm, and the modulus E of the elastomeric composition constituting said annular band and said walls is between 0.05 and 0.5 Kg/mm2.
10. The elastically deformable member of Claim 1 wherein said closed hollow bodies form a single body with said annular band.
11. The elastically deformable member of Claim 1 wherein said closed hollow bodies have such a volume that said structure has a radial section height between 60 and 85% of the tire cavity in which it will be installed.
12. The elastically deformable member of Claim 1 wherein a second annular band is disposed in contact with the external radial portion of each of said closed hollow bodies, said band at atmospheric pressure, being in a stretched condition and having a development which corresponds, at least with the ideal circumference by which said closed hollow bodies are circumscribed.
13. The elastically deformable member of Claim 12 wherein said second annular band forms a single body with said closed hollow bodies.
14. The elastically deformable member of Claim 1 wherein the number of said closed hollow bodies is between 8 and 360.
15. A vehicle tire and rim-assembly comprising inside the cavity of the tire the elastically deformable member of Claim 1, said-member being so disposed that said first annular band faces the rim and the remaining part of the tire cavity contains air at inflation pressure.
16. A tire-rim assembly as in Claim 15 wherein under the tire inflation pressure conditions, said elastically formable member is disposed in a first position in which the stretched condition of the said first annular band is reduced and it has a development at least equal to the minimum development of said rim, the axially outward portion of the walls of each closed hollow body leaning against the internal surface or said tire, said member being able, under working conditions, to take, for the portions of its development which are periodically opposite to those portions subject to being squeezed under load, the same structure into a second position in which at least the relative length of said annular band is deformed according to a greater development than that corresponding to the first position, the surface radially outside the totality of the closed hollow bodies being in contact with at least the tire internal surface underlying the tread, in such a way as to support said tire in case of accidental deflation.
17. The tire-rim assembly of Claim 15 having a lubricant inside its cavity.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT24792/76A IT1079133B (en) | 1976-06-28 | 1976-06-28 | ELASTICALLY DEFORMABLE STRUCTURE FOR SAFETY TIRES |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1063915A true CA1063915A (en) | 1979-10-09 |
Family
ID=11214754
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA281,465A Expired CA1063915A (en) | 1976-06-28 | 1977-06-27 | Elastically deformable insert for a vehicle tire casing for support when the casing is deflated |
Country Status (20)
| Country | Link |
|---|---|
| JP (1) | JPS532805A (en) |
| AR (1) | AR212271A1 (en) |
| AT (1) | ATA460477A (en) |
| AU (1) | AU2633077A (en) |
| BE (1) | BE856149A (en) |
| BR (1) | BR7704118A (en) |
| CA (1) | CA1063915A (en) |
| DE (1) | DE2728117A1 (en) |
| DK (1) | DK286477A (en) |
| ES (1) | ES229675Y (en) |
| FI (1) | FI771561A (en) |
| FR (1) | FR2356529A1 (en) |
| GB (1) | GB1583185A (en) |
| IT (1) | IT1079133B (en) |
| LU (1) | LU77634A1 (en) |
| NL (1) | NL7706006A (en) |
| NO (1) | NO772260L (en) |
| SE (1) | SE7707463L (en) |
| TR (1) | TR19902A (en) |
| ZA (1) | ZA773704B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55160610A (en) * | 1979-06-02 | 1980-12-13 | Toyobo Co Ltd | Safety tire for motorcar |
| FR2476552A2 (en) * | 1980-02-21 | 1981-08-28 | Hutchinson Mapa | Ancillary tyre chambers which can dilate to fill a punctured tyre - to provide support without rubbing wear |
| GB2214877A (en) * | 1988-02-09 | 1989-09-13 | Sidney Inwood | Preventing tyre deflation |
| GB2293357A (en) * | 1994-09-22 | 1996-03-27 | Michael Cooney | Safety tyre |
| FR2893536A1 (en) * | 2005-11-22 | 2007-05-25 | Michelin Soc Tech | FLAT ROLL SYSTEM COMPRISING SELF-CONTAINING CELLS |
| JP5457850B2 (en) * | 2010-01-18 | 2014-04-02 | 住友ゴム工業株式会社 | Run-flat tire assembly |
| US9302539B2 (en) * | 2012-04-25 | 2016-04-05 | Lindsay Corporation | Wheel and tire assembly |
| JP6435835B2 (en) * | 2014-12-12 | 2018-12-12 | 横浜ゴム株式会社 | Assembly tire |
| JP6435840B2 (en) * | 2014-12-17 | 2018-12-12 | 横浜ゴム株式会社 | Assembly tire |
-
1976
- 1976-06-28 IT IT24792/76A patent/IT1079133B/en active
-
1977
- 1977-05-17 FI FI771561A patent/FI771561A/fi not_active Application Discontinuation
- 1977-06-01 NL NL7706006A patent/NL7706006A/en not_active Application Discontinuation
- 1977-06-16 GB GB25205/77A patent/GB1583185A/en not_active Expired
- 1977-06-21 JP JP7380577A patent/JPS532805A/en active Pending
- 1977-06-21 ZA ZA00773704A patent/ZA773704B/en unknown
- 1977-06-22 TR TR19902A patent/TR19902A/en unknown
- 1977-06-22 AU AU26330/77A patent/AU2633077A/en active Pending
- 1977-06-22 DE DE19772728117 patent/DE2728117A1/en not_active Withdrawn
- 1977-06-22 ES ES1977229675U patent/ES229675Y/en not_active Expired
- 1977-06-24 BR BR7704118A patent/BR7704118A/en unknown
- 1977-06-27 LU LU77634A patent/LU77634A1/xx unknown
- 1977-06-27 BE BE178812A patent/BE856149A/en unknown
- 1977-06-27 CA CA281,465A patent/CA1063915A/en not_active Expired
- 1977-06-27 AR AR268199A patent/AR212271A1/en active
- 1977-06-27 NO NO772260A patent/NO772260L/en unknown
- 1977-06-28 AT AT460477A patent/ATA460477A/en not_active Application Discontinuation
- 1977-06-28 DK DK286477A patent/DK286477A/en unknown
- 1977-06-28 FR FR7719810A patent/FR2356529A1/en active Pending
- 1977-06-28 SE SE7707463A patent/SE7707463L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ES229675Y (en) | 1978-01-01 |
| NO772260L (en) | 1977-12-29 |
| ZA773704B (en) | 1978-05-30 |
| BE856149A (en) | 1977-10-17 |
| FR2356529A1 (en) | 1978-01-27 |
| BR7704118A (en) | 1978-03-28 |
| LU77634A1 (en) | 1977-10-03 |
| TR19902A (en) | 1980-04-21 |
| ATA460477A (en) | 1979-12-15 |
| ES229675U (en) | 1977-09-01 |
| DK286477A (en) | 1977-12-29 |
| DE2728117A1 (en) | 1978-01-05 |
| IT1079133B (en) | 1985-05-08 |
| SE7707463L (en) | 1977-12-29 |
| JPS532805A (en) | 1978-01-12 |
| NL7706006A (en) | 1977-12-30 |
| AR212271A1 (en) | 1978-06-15 |
| AU2633077A (en) | 1979-01-04 |
| FI771561A (en) | 1977-12-29 |
| GB1583185A (en) | 1981-01-21 |
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