CA1249210A

CA1249210A - Automotive vehicle tire and mounting system therefor

Info

Publication number: CA1249210A
Application number: CA000531449A
Authority: CA
Inventors: Pierre J. Augier
Original assignee: Uniroyal Inc
Current assignee: Uniroyal Inc
Priority date: 1983-04-12
Filing date: 1987-03-06
Publication date: 1989-01-24

Abstract

Abstract of the Disclosure A pneumatic tire and a mounting system therefor, having con-structional features designed to provide optimized operational charac-teristics. The tire has a low aspect ratio and a low height ratio .theta. conforming substantially to the relations = 0.236/.theta. and 0.32 .theta. 0.39. The mounting system includes a vehicle axle-borne drum and a pair of ring members adapted to be securely fastened to the drum, each ring member defining a bead seat, a bead restraining flange and a sidewall-supporting extension, and the ring members being adhered to the tire at the beads and the lower sidewalls. A layer of a suitable sealant at the juncture between each ring member and the drum renders the joints airtight.
The tire includes a single ply radial carcass the turn-ups of which terminate in the lower sidewall regions of the respective adhesion zones between the tire and the ring members, and each of the beads is reinforced by a relatively thin, lightweight metal member in the form of a single loop having no free ends. A novel valving system for the tire, including a passageway in one of the ring members covered at one end by a quantity of a sealant having self-sealing properties, is also provided. This abstract is not to be taken either as a complete exposition or as a limitation of the present invention, however, the full nature and extent of the invention being discernible only by reference to and from the entire disclosure.

Description

AUTOMOTIVE VEHICLE TIRE
AI~D MOUNTIMG SYSTEM THEREFOR
This invention relates to an automotive vehicle tire and a mounting system therefor, the design and cons~ruction of which 5 cooperate to provide an optimized se~ of structural and operational characteristics .
Automotive vehicles, especially automobiles and trucks, which are adapted to be driven (or, in the case of trailers, to be towed) at relatively high speeds over streets and highways, ride on pneu-10 matic tires mounted on metal wheels, each such wheel having anannular body portion and a transverse rim portion welded to the outer periphery of the body portion, the rim portion terminating at its opposite lateral boundaries in a pair of generally upstanding rim flanges and defining intermediate the flanges directly adjacent 15 thereto a pair of bead sea~s on which the beads of the associated mounted tire are located. In practice, the rim portions of ~he wheels for passenger cars and light trucks are usually of the "drop center" variety, i.e. each wheel rim is a one-piece structure and is formed with a circumferential deep well intermediate the rim flanges.
20 Such a deep well is provided ~o enable the circumferentially essen~
tially inextensible but radially somewhat deformable beads of a tire to be slipped one after the other in well-known fashion over one of the rim flanges and onto the wheel rim. As is well known, of course, once the two beads of a tire are located between the rim 25 flanges of a wheel, the tire is infla~ed to a pressure sufficiently high to cause the beads to be shifted laterally (i . e . axially) out-wardly of the rim onto the bead seats and up against the rim flanges .
A tire and wheel combination o~ this type is subject to a 30 number of drawbacks and disadvantages, however, both in terms of problems that arise from the mounting of the tire on the wheel and in terms of problems that arise from the structural and operational characteristics of the tire per se, the wheel per se, and the as-sembled tire/wheel combination. Some o~ these, without intending 35 them to be an exhaustive cataloguing, may be brie~ly descrihed 3S
f~llows .

J ~ ,3 ~

I . Mo~lrJ ~ ~5 Since wheel rlm flanges, being intended to laterally confine and retain the tire beads on the rim, extend essentially radia]ly outwardly from the base of the r~m, i.e. at an angle ~f usually at 5 least about 45 to the base and frequently almost perpendicularly to the same, the outermost diameters of the rim flanges are ~f neces-sity considerahly larger than the rim diameter, i.e. the diameter of the rim in the region of the bead seats. Thus, with the inner diameter of the beads of the tire being substantially equal to ~he 10 rim diameter, a portion of one bead has to be first forced over one of the rim flanges and dropped into the well, after which a lever-like tool is run around the wheel between the bead and the rim flange to force the remainder of that bead over the rim flange and onto the rim. The same procedure must then be repeated with ~he 15 second bead of the tire. The operation of so forcing a tire bead over a wheel rim flange can, however, damage the rubber covering o the bead, thereby creating a situation where not only could air ultimately leak out of the tire via the bead/rim interface but dirt and moisture could get in under the bead and the deterioration of 20 ~he rubber could even be propagated from the damaged portion of the bead to other parts of the tire. Again, once a tire has been so passed onto a wheel rim, it must then, as previousiy mentioned, be in1ated to a pressure sufficiently high to displace or "pop" the beads onto their respective bead seats. This, however, gives rise 25 to the possibility that the tire will be mismounted, i . è . will be mounted with an improper bead seating or with the beads not in full engagement with the rim flanges, which could be due to defects in the rim construction as well as to dimensional differences between the tire beads on the one hand and the rim on the other (it is a 30 well-known fac-~ that standarized metallic vehicle wheels, as manu-factured, include appreciable dimensional tolerances~. Generally, also, the mounting of the tire on the wheel requires the prior application of a lubricant to either the beads of the tire or the bead seats on the wheel rim to facilitate the shiting of the beads 35 onto the bead seats, which is an extra operation to begin with and a messy one at that and does not necessarily ensure ~he proper seating of the ~eads. The presence of ~he deep well in the wheel ?

rim, ~f c~urse, also materially reduces the degree of clearance between the rim as a whole and the wheel axle, thereby reducing the amount of space available ~or location of the vehicle brake for that wheel.
lI. Structural/Operational Prob~ems Whenever a vehicle is in motion, the tires on which it is riding are subject to a number o~ severe stresses. In a conventional tire/wheel combination, however, the tire is a separate entity ~rom and is not adhered to the metal wheel rim. Of necessity, there-fore, when the tire is placed under torque due to braking or ac-celeration oI the vehicle, there will be, especially in the case of a tubeless tire, a tendency for some circumferential slippage of the tire relative to the bead seats, and hence for some degree of ~ear at the beads. The same lack of adhesion between the beads and the wheel rim, of course, also permits the beads to rock radially or transversely away from the rim flanges as the sidewalls are flexed while the tire is rolling over the ground, especially during corner-ing or when hitting a curb during a parallel parking maneuver. As each sidewall is flexed, moreover, a substantial amount of rubbing or chafiny of the sidewall occurs where the portion of the sidewall just radially outwardly of the bead comes into repeated and inter-mittent contact with the radially outwardmost boundary region of the rim flange. Thus, perhaps because of manufacturing tolerances but perhaps also because the tire is constantly subjected to circum-ferential bead slippage, radial bead rocking, and bead chafing, small air leaks tend to develop at the bead/rim interfaces. Con-comitantly, another possibility of an air leak developing exists at the location of the valve hole normally provided in the vehicle wheel rim to accommodate the separately inserted tire inflation valve.
Should enough air escape from the tire through such air leaks, however, it may become possible for at least one of the beads effectively to roll laterally inwardly off its respective bead seat, thereby possibly causing a loss of control of the vehicle by the driver while the vehicle is in high speed motion.
Still further, in order to render the beads essentially resistant to circumferential extension as far as possible, each bead is of necessity reinforced by a heavy bead wire arrangement, generally .

in the form of a strand of one or more relatively thick wires or ribbons wound for a multiplicity of ~urns into a bulky and circum-ferentially substantially inextensible albeit radially deformable bead wire core bundle. The cost of manufacturing such bead wire cores 5 and preparing then~ for incorporation in the tire is, of course, a significant e]ement of the overall cost of manufacturing the tire.
Moreover, the bulk of these bead wire cores makes it necessary that the radially inward regions of the sidewalls contiguous ~o the beads be made correspondingly thick through the addition of extra 10 amounts of rubber. The weight of this added rubber, however, constitutes a substantial part of the weight of each tire and hence of the overall weight of the vehicle (and the vehicle weight is even higher whenever a fifth or spare tire is being carried in the vehicle), and obviously the power which rnust be expended in 15 driving the vehicle corresponds directly to the weight of the vehicle. Finally, it is well known that if, while the vehicle is in hi~h speed motion, the pressure in a tire becomes too low, whether by a process of slow leakage or through a more or less catastrophic deflation (such as in case of a blowout), so that the beads become 20 able to move away from their associated rim flanges and laterally inwardly of the rim, the beads can actually come into the region of the well portion of the rim, drop into the well and then pass off the rim to effectively demount the tire from the wheel in a rapid sequence of stages that is essentially the reverse of the herein 25 previously described sequence followed during the mounting of the tire on the wheel. Thus, not only does a conventional tire/wheel combination not provide any substantial "run flat'l capability at high speeds, but the aforesaid ability of the deflated tire to ~e stripped off the wheel rim while the vehicle is moving at a high speed can 30 bring about disas~rous consequences to the occupants of the dis-abled vehicle as well as to innocent passers by.
As is also well known, problems in the performance of a tire (e.g. in its ride and corneriny properties) may arise due ~o the structural characteristics of the tire. Thus, on the one hand in 35 conventional tires it is frequently the pracLice to extend one or more of ~he fabric carcass plies around the bead reinforcement and well up into the proximate sidewall, the theory being tha~ this will provide an extra layer of fabric reinforcement in ~he region of the sidewall where bead chafing is most likely to occur. However, the cut end of each such turn-up ply then constitutes a mechanical discontinuity in the sidewall which, as the sidewall is repeatedly flexed, may become separated from the overlying sidewall rubber and thereby weaken the tire sufficiently to render i~ unfit for use.
On the other hand, the almost worldwide trend in tire manufacture currently is toward tires with ever lower aspect ratios. The "aspect ratio" of a tire, by definition, is the ratio of the section height of the tire to the width of the section at its widest portion, with the section height being the perpendicular distance between two lines parallel to the tire axis, one located at the toe ring dia-meter and one tangent to the outer surface of the tread at the apex thereof, i . e . where it is intersected by the mid-circumferential plane of the tire. A low aspect ratio tire, however, while generally characterized by good handling (cornering) and rolling resistance properties, also tends to give a rough ride and to be subject to certain sidewall problems.
1~ should be noted at this point ~hat some attempts have been made hy others in the art to overcome some of the herein outlined disadvantages of conventional tires and tire/wheel combinations.
For example, wheels with semi-drop center rims ~rims having only a shallow medial well formed therein) and flat base rims ~rims having no well at all formed therein) have long been known for use especially with heavy trucks and other heavy-duty vehicles to facilitate ~he mounting and demounting of the usually large tires of such vehicles. A rim of such a wheel generally has one fixed and one demountable flange, with the demountable flange fitting in~o a gutter on the outboard edge of the rim to hold the tire in place.
Wheels with divided rims for both large and small vehicles, especially military vehicles, are also known. A divided wheel rim consists of tw~ sections of either equal or unequal width, one of which carries a plurality of circumferentially distributed, axially extending studs or bolts while the other section is provided with a corresponding number of holes, so that the two sections can be bolted together with ~he aid of nuts in the same manner that a wheel is secured to a vehicle axle hub. The use of a divided rim of either of these types, however, entails the use of a special beadlock, of either the continuous channel type or the hinged segmental type, to hold a tire in position on the rim.
Again, in order to avoid the problems of circumferential bead slippage and radial bead rocking and roll-off, and in order to concomitantly provide some degree of run-flat capability, the cementing of the beads of a conventional tire directly to a wheel rim has been suggested, as shown, for example, by ~. S. Patent No.
3,938,573. The attainment of a limited degree of run-flat capability 10 through the molding of a specially configured beadless tire directly onto a wheel rim entirely devoid o~ any rim flanges and bead seats has a]so been suggested, as shown, ~or example, by U. S. Patent No. 4,253,510. This patent also discloses the use of a wheel with a fla t base rim to provide greater space for accommodating a larger 15 brake for the wheel. To the best knowledge of the present appli-cant, however, these approaches have so far not been adopted and implemented in the case of pneumatic tires by either tire or vehicle manufacturers (if they have been adopted at all, then this has certainly not been done on a large, industry-wide scale), nor have they been demanded by the purchasers and users of such products.
It is the primary objective of the present invention, therefore, to provide a pneumatic vehicle tire and also a mounting system therefor including, inter alia, a novel vehicle axle-borne drum, the designs and constructions of which are optimized to impart an 25 overall optimized set of structural features and operational proper-ties to the tire per se as wel] as to the ultimate tire/drum combina-tion, thereby to enable the aforesaid and other drawbacks and disadvantages of conventional tires, wheels and tire/wheel combina-tions to be effectively avoided while at the same time enabling a 30 number of heretofore unattainable advantages, more particularly described hereinafter, to be achieved.
Generally speaking, within the framework of its objectives the present invention provides a tire having an op timized overall con-struction and configuration and including an orientation of the 35 sidewall portions located just radially outwardly o~ and contiguous to the beads at a relatively low angle of about 25~ to the axis of the tire. Associated with the tire are two ring members which con-stitute a part of the mounting system for the tire and define therequisite bead seats and a pair of bead restraining flanges, the latter being of lower than conventional heigh~ and having respective shallow, low-angle ex~ensions matched to the a:foresaid low-angle 5 sidewall portions. The ring members, over substantially the full extent of the bead seats, the bead restraining flanges and the low-angle extensions, are permanently adhered to the tire, e.g. by being bonded or vulcanized thereto, in the respective regions of the beads and the said radially inwardmost regions of the sidewalls 10 contiguous to the beads. The ring members are further adapled to be mechanically releasably secured, as by means of bolts, lugs, or the like, to a vehicle axle-borne drum adjacent the opposite, i. e.
the inboard and outboard, lateral boundaries of a peripheral skirt portion of the drum. In conjunction therewith, the beads are lS characterized by a novel and lightweight bead reinforcement, and further by low turn-ups of the carcass reinforcing fabric which terminate with the cut ends of the fabric located within the confines of the adhesion zones between the tire and the ring members, preferably in the regions over which the respective lower sidewall 20 portions of ~he tire are adhered to the ring members.
The invention further provides a novel tire mounting drurn having a body that is adapted to be securely bolted to the hub of a vehicle axle and further having 3 flat peripheral skirt that is provided with a relatively low or shallow flange section only at its 25 inboard side (i . e . the side which will face inwardly of the vehicle when the drum is properly mounted on the axle). The skirt has a relatively gentle, radially inward taper of about 3 to the drum axis from the f]anged, inboard side of the drum toward its flangeless, outboard side. In conjunction therewith, the inboard ring member 30 is contoured to mate fully with and be capable of being secured to the said flarige section of the skirt, which thus provides the 5Up-port for the inboard ring member and properly positions the in-board bead seat and bead restraining flange. Correspondingly, the outboard riny member is contoured to be capable of being secured 35 to the flangeless side of the drum so as to properly position the outboard bead seat and bead restraining flange.

The invention still further provides an airtight tire/drum combination through the application of a suitable sealant to the drum in the regions of the inner junctures between the skirt por-tion thereof and the two ring members. As presently contemplated, the sealant preferably is a material of any of the types disclosed in V. S. Patents Nos. 3,9~1,342, 4,012,567 and 4,064,922, but lt will be apparent tha-t possibly o-ther types of ~ealing materials having acceptable physical p~-oper-ties m~ly also be used.
In accordance with a refinement of the invention, the outboard ring member may be further contoured to provide at one point of its periphery a suitable, preferably small depression or embossment, the same ~eing so located on the ring contour that when the said ring member is affixed to the drum, the depression forms an in-wardly open pocket intermediate the outboard bead seat and the region of juncture between the outboard ring member and the drum.
The depression is provided at its outwardly directed bottom ~ith a small hole and contains a suitable sealing material, preferably a sealant of the same types as are mentioned above, in an amount sufficient to cover the said hole fully. The sealant-containing pocket (because of its tackiness and self-sealing properties, the sealant will not flow out of the hole) thus constitutes a leak-proof valving system for the tire. Inflation of the tire can be easily effected b~ simply inserting and pushing through the hole and the sealant in the poclcet, a hollow inflation needle having an air outlet opening at its leading free end and having its hollow in-terior in communication via its trailing end with a source of pressurized air located exteriorly of the tire. During such penetration of the sealant by the needle, the sealant flows about the needle and pre-vents loss of air. Thereafter, upon withdrawal of the needle the sealant will simply be drawn in behind it to fill the perfora-tion formed by the needle (as will be understood from the above-identi-fied patents).
The op timized designs and constructions of the tire and the mounting system therefor according to the present invention will also be characterized by still other features. For example, the tire when in an inflated but unloaded sta~e is characterized by a special relationship ~etween its aspect ratio (as hereinabove defined) and its height ratio. The "height ratio" o~ a tire, by definition, is the ratio of thP section height oi the tire to ~he radial distance between 5 the tire axis and the previously mentioned line which is parallel to t} e tire axis and tangent to the tread surface at the apex thereof.
The tire is ~urther characterized by a novel construction and con-figuration o~ the bead reinforcements and 3:)y high-hardness extra-length apex strips which ex~end from the bead reinforcements and 10 terminate beyond the adhesion zones between the ring members and the lower sidewall regions of the tire, generally at a line located in the region between 1/4 and 1/3 o~ the height of the tire section as measured from the toe ring diameter of the tire. On the other hand, the mounting system is characterized, ~or example, by the 15 presence of predetermined taper angles not only ~n the portions of the ring members adhered to the tire but also on the drum skirt, by special attachment systems for securjng the ring members to the drum, and by a special ring width ratio. The "ring width ratio" of the tire/drum combination, by definition, is the ratio of the dis-20 tance between the outer extremities of the adhesion zones to thewidth of the tire section at its widest portion.
Through the implementation o~ the present invention as afore-said, mounting and demounting of the tire is greatly simplified.
Thus, by virtue of the absence of an outboard flange on the drwn 25 per se and the tapering oI the flat skirt portion thereof, the tire bead carrying the inboard ring member can be easily and without any forced de~ormation slipped onto the drum from the outboard side of the latter until the said ring member is seated on the existing flange portion of the drum skirt at the opposite, inboard 30 side oi the drum. It is because of this, of course, since the bead reinforcement is not subjected to deformations and distortions during mounting or demounting of the tire, that the bead rein-forcement according to the present invention can be made much thinner and lighter than conventional multiple-turn multiple-wire 35 bead core bundles; in fact, it is contemplated to use as a bead rein~orcement a rnetal rnember in the form of a ~ingle loop hav~ng no free ends, a generally inwardly convex arcuate inner surface, and c~

preferably also a longitudinal peripheral channel iormed in the outer surface of the metal member, the presence of the channel unparting to the member a generally U-shaped cross-section. Moreover, with a laver of sealant having been previously applied ts the drum both 5 at the base of the inboard skirt flange portion and at the juncture between the skirt and the body of the drum, the subsequent tightening of the two ring members against the drum automatically creates an airtight seal around the entire circumference of l:he drum .
Still further, by virtue of its aspect ratio to height relation-ship, a tire according to the present invention is found to have a greater load-carrying capacity compared to its own weight, i . e . to have an on the average 10% higher "tire efficiency" or "load effi-ciency" ~the ratio of ~ire load to tire weight) than a conventional tire of equivalent strength. The converse of this is, of course, that for equivalent load-carrying capacities the tire of the present invention weighs considerably less ~han a conventional tire. ~t the same time, the fact that the tire according to the present invention has, as previously mentioned, low-angle lower sidewall regions and apex or fiiler strips of extra length and higher hardness than a conventional tire enables optimum tire performance properties (ride, handling, wear resistance, fatigue resistance, Ptc.) to be achieved.
The foregoing and other objects, characteristics and advan-- tages of the presen~ invention will be more fully understood from the following detailed description thereof when read in conjunction with the accompanying drawings, in which:
Eig. 1 is a fragmentary, partly elevational, transverse or axial section through a tire/drum combination according $o the present invention;
Fig. 2 is a view simi]ar to Fig. l but illustrates the tire with its two adhered ring members in the process o~ being mounted on the drum;
Fig. 3 is a greatly enlarged, fragmentary, sectional view of the inboard bead and lower sidewall region and the thereto adhered ring member of the tire shown in Figs. 1 and 2, and illustrates certain additional constructional details thereof;

Fig. 4 is an P]evational view of the pneumatic tire and its adhered outboard ring mernber as seen from the outboard side thereo~ and shows the elements which conslitute a part of the attachment system for this ring member and the drum;
Fig. 5 is an elevational view of the tire/drum combination as mounted on a vehicle axle, the view being taken from the outboard side of the tire/drum combination and showing further elements of the outb~ard ring member attachment system;
Figs. 6 and 7 are enlarged, fragmentary, elevational views of the tire/drum combination as seen from the outboard side thereof and i]lustrate the manner in which the attachment of the outboard ring member to the drum is effected and also show the location of the novel valving system of the present invention;
Figs. 8 and 9 are enlarged, fragmentary, perspective views of the attachment system for the inboard ring member and the ~langed portion of the drum skirt in two different sequential positions during the mounting of the tire on the drurn;
Fig. 10 is a fraymentary sectional view similar to Fig. 1 but with the section taken on a different line and illustrates the tire valving system according to the present invention; and Figs. 11 and 12 are fragmentary sectional views of the valving system sho~n in Fig. 10 and illustrate the manner of use thereof.
Referring now to the drawings in greater detail, in Fig. 1 there is shown a tire and mounting drum combination ~0 including a - 25 pneumatic tire 21 and a drum 22 on which the tire is mounted in a manner to be more fully described hereinafter. The drum 22, which has a body portion 22a and a transverse peripheral skirt portion 22b, is secured at its mid-region to the hub 23 oI a vehicle axle 24 by means suitable bolts or screws 23a having specially configured heads, for example heads which are provided, as sche-matically indicated in Figs. 6 and 7, with internal hexagonal sockets (or any o~her type of special tool-engaging portions) designed to inhibit removal of the drum from the axle without the use of special tools. In acc~rdance with the present invention, the drum skirt 22b (which encloses the vehicle brake, not shown) is provided at its free end with a circumferential flange section 25. No corres-ponding flange section is provided at the other side of the drum.

By virtue of its form, it will be understood, the drum 22 is uni-directional, i . e . when properly mounted on a vehicle axle i~ will always have i~s flanged side directed inboard of the vehicle ~to the left in ~ig . 1 ) and its flangeless side directed outboard of the 5 vehicle (to the right in Fig. 1), and correspondingly, for reasons which will become clear presently, the tire 21 will always have to be mounted on the drum with a given one of its sides directed inboard and the other side directed outboard of the vehicle, so that, by design, mismounting of the tire is rendered effectively impossible.
10 Portions of the drum 22 and the tire 21 are thereore, on occasion designated herein as being either "inboard" or "outboard" portions.
The tire 21 has a generally toroidal shape and includes a tread 26 overlying the circumferential crown region of the tire, and a pair of sidewalls 27 and 28 extending generally radially inwardly 15 from the tread and terminating in a pair Df beads 29 and 30 rein-forced interiorly by a pair of metal members 31 and 32. The body of the tire is reinforced by a carcass ply 33 of tire cords running from one bead to the other and anchored to the bead reinforcements 31 and 32, and a tread-reinforcing belt 34 of tire cords is inter-20 posed between the tread and the underlying portion of the carcassply over the entire circumferential crown region of the tire. The anchoring o~ the carcass cords to the bead reinforcements is ef-fected by turning the end regions 33a and 33b of the ply ~3 up around the meta] members 31 and 32 from the inside of the tire to 25 the outside, and respective apex or filler strips 35 and 36 are fitted into the spaces above the metal members and between the main and turned-up portions of the carcass ply. Carcass ply turn-ups, bead wire reinforcements and apex strips are, of course, per se comrnon elements of pneumatic tires, but as will be more 30 fully explained presently the forms and arrangements of these elements in the tire 21 differ materially from those of their Icnown antecedents in conventional tires and constitu~e material parts of the present invention.
It should be noted, in passing, that in the illustrated con-35 struction of the tire 21, the carcass 33 is constituted by a singleply of tire cords disposed in radial planes, i. e. with the cords running at an angle of substa~ntially 90 to the mid-circumferential $~

or median equatorial plane of the tire, and the ~elt 34 (as is con-ventional in radial ply tires) is constituted by a superposed pair of plies 34a and 34b of tire cords extending generally circumferentially of the tire at Dpposed relatively low bias angles to the m3d-circum-5 ferential plane, i.e. with the cords in each belt ply running at anangle of about 15-35, and preferably about 25, to the mid-cir-cumferential plane and crossing the cords of the other belt ply.
Also, the tire cords of the carcass and the belt may be made of any of the materials that are conventionally used by tire manufacturers 10 in such products, namely, rayon, nylon, polyester, steel, g]ass fiber, aramid fiber, and the like. Correspondingly, the drum 22 and its component parts and adjuncts will generally be made of metal, but they could be molded of suitable reinforced plastics, e.g. mo]ded fiberglass. It will be understood, however, that one lS or more of these known aspects of the various constructions des-cribed could be modified as desired without in any way affecting the fundamental principles or the ~mplementation of the present invention .
As best shown in Figs. 1, 2 and 3, the tire and drum combina-20 tion according to the present invention further includes a pair ofring members 37 and 38 which are contoured to define respective bead seats 37a and 38a tapering radially inwardly of the tire at angles of about 5 to the tire axis (i.e. with a tolerance of about 1~) and respective contiguous bead restraining flanges 37b and 38b, 25 the latter extending generally radially outwardly of the tire almost perpendicu~arly to the tire axis and having respective sidewall-supporting extensions 37c and 38c oriented at relatively shallow angles of about 25 to the tire axis. The ring members further have respective outer peripheral extensions 37d and 38d which (fGr 30 a purpose that will become clear as the description proceeds ) are oriented to extend almost parallel to the tire axis.
The ring members 37 and 38 are permanently adhered to the tire 21 at the inboard and outboard sides of the tire. Thus, the zone of adhesion between the sections 37a, 37b and 37c of the 35 inboard ring member 37 and the tire (this zone is designated Z and is diagrammatically represented by the cross-hatching in Fig. 3) extends over the surface Df the foot 29a of ~he bead 29 from its heel 29b to its toe 29c, thence over the outer surface of the side portion 29d of the bead, and finally over the outer surface of the region 27a of the inboard sidewall 27 located just radially outwardly of and con~iguous to the bead 29. The zone of adhesion between the sections 38a, 38b and 38c of the outboard ring member 38 and the tire correspondingly extends over the surface of the ioot 30a of the bead 30 from its heel 30b to its ~oe 30c, thence over the outer surface of the side portion 30d of the bead 30, and finally over the outer surface of the region 28a of the outboard sidewall 28 located just radially outwardly of and contiguous to the bead 30. The adhesive attachment of the ring memhers 37 and 38 to the tire can, of course, be effected during the manufacture of the tire by vul-canizing the ring members (if need be, suitably pretreated with a metal-to-rubber or a plastics-to-rubber adhesion-promoting sub-stance of any of the types well known in the art) directly to the tire in the mold. Alternatively, however, it may be effected after the manufacture of the tire per se by adhering the ring members to the appropriate portions of the tire with the aid of suitable adhe-sive or bonding agents known in the industry for bonding rubber to metals, for example, adhesives such as are available commercially ~rom Lord Manufacturing Company under the registered trademark CHEMLOK .
As further clear]y shown in Figs. 1, 2 and 3, the turned-up portions 33a and 33b of the carcass ply 33 are considerably shorter than is usually the case in conventional tires. In particular, the ply turn-ups terminate and are completely confined within the por-tions of the adhesion zones defined between the sections 37c and 38c of the ring members 37 and 38 and the respective tire side~all regions 27a and 28a . Concomitan tly, the rubber apex or filler strips 35 and 36 used for the purposes of the present invention have a relatively high Shore "A" hardness (on the order of about 90-94) and are considerably longer than is usually the case in conven tional tires . In particular, the apex strips extend from the bead reinforcements 31 and 32 into the sidewalls 27 and 28 and terminate beyond the adhesion zones but short of the widest portion of the tire, i . e . short of the location of the greatest separation, denoted by the dimension g in Fig. 1, between the sidewalls 27 and p~ ?

28. Preferably the apex s~rips terminate at a location between about 1/4 and 1/3 of the section height of the tire, the section height, denoted by the dimension h in Fig. 1, being the distance from a line paral]el to the axis of the tire and constituting the toe 5 ring diameter of the tire to a line parallel to the axis and tangent to the outer surface of the tread at its apex (i . e . at the mid-cir-cumferential plane). In the present case the toe ring diameter is taken to be the line, parallel to the tire axis, which passes through the two points of intersection (on]y one of these, designated 39, is 10 shown in Fig. 3 only) between the imaginary straight-line exten-sions of the tapered bottom surfaces of the bead portions 29a and 30a on the one hand and the associated generally radial outer side surfaces of the bead portions 23d and 30d on the other hand.
The utilization of these features leads to a number of ad-15 vantages. One is due to the fact that, with the carcass ply turn-ups 33a and 33b terminating in the lower or radially inwardmost sidewall portions 27a and 28a, the remaining outer portions of the sidewal]s are free of the mechanical discontinuities that would other-wise be present therein were the cut ends of the ply turn-ups to 20 be located in the outer sidewall portions beyond the ends of the adhesion zones. This arrangement, thereore, effectively renùers impossible the occurrence of turn up ply separations in the outer sidewall portions (which is a substantial risk in a conventional tire because the sidewalls thereof, where the ply turn-ups terminate, 25 are subject to severe flexural stresses whenever the tire rolls over the ground under load). Conversely, turn-up ply separations cannot occur at all in the lower sidewall regions 27a and 28a because the same are not subject to any ~lexural stresses when the tire is in use, being adhered to as well as fully supported by the 30 ring member sections 37c and 38c.
Another advantage is due to the fact that the supported lower sidewall regions 27a and 28a are oriented at relatively shallow angles of about 25 to the tire axis (in what may be termed in effect a cantilever arrangement). This arrangement has certain 35 beneficial effects on the ride and handling properties of the tire, i . e . it imparts an acceptable vertical elasticity to the tire and thereby tends to compensate for the hereinbefore mentioned some-what less desirable properties of the tire that result from i~s low aspect ratio. Moreover, the adhesiGn of the lower sidewall regions and the beads to the respective sections of the the ring members in the manner shown ensures that circumferential bead slippage, radial bead rocking and bead roll off, and bead chafing are effectively 5 inhibited. The purpose of the angling ~f the ring member exten-sions 37d and 38d downwardly or radially inwardly relative to the sections 37c and 38c, and hence away from the unsupported regions of the sidewalls 27 and 28, will now also be clear. Thus, by virtue of this arrangement the pctential for a bead chafing-like rubbing 10 contact between the ring members and the tire sidewalls where the unsupported regions thereof adjoin the supported and adhered regions is substantially minimized.
As previous]y mentioned, the tire according to the present in-vention is also characterized by novel internal bead reinforcements.
15 Basically, these novel bead reinforcements can have various cross-sectional configurations, as will be more fully described hereinafter, but in all cases each reinforcement will be in the form of a solid single-body or unitary metal member having no free ends, which can be achieved, for example, either by directly forming the mem-20 ber as a full ring or by first forming the member as a linear body,then bending the same into a circle of appropriate diameter to bring the ends of the body into contact with each other, and finally butt-welding the said ends to each other. Furthermore, in accor-dance with the presently contemplated best mode of practicing the 25 invention, the reinforcing members 31 and 32 preferably a]so have a generally U-shaped cross-section with a substantia]ly uniform wall thickness. Thus, as best shown in Fig. 3 for the inboard bead reinforcement 31, the same is characterized by an inner surface 31a of convexly semicircular curvature and an outer surface having a 30 pair of flat, circumferentially extending, lateral regions 31b and therebetween a circumferentially extending, medial, outwardly open channel 31c of concavely semicircular curvature. Correspondingly, the outboard bead reinforcement 32 is identical in all respects with the reinforcement 31, as can be seen from Figs. 1, 2 and 10, being 35 characterized in the preferred form by an inner surface 32a of convexly semicircular curvature and an outer surface having a pair of flat, circumferentially extending, lateral regions 32b and a , ~7~z~ o~ 3 medial, outwardly open, circumferentially extending channel 32c.
The terms "inner" and "outer" as applied to the surfaces of the reinforcement members 31 and 32, it should be understoDd, are here used to denote the respective surfaces of ~he annular or ring-shaped reinforcements which are directed inwardly and outwardly of the latter. The specific cross-sectional dimensions of each such bead reinforcement (namely, the radius of curvature of its inner surface 31a or 32a, the radius of curvature of its channel 31c or 32c, the "height" of the U, i.e. the distance from the plane of the ends of the legs 31b or 32b of the U to a plane tangent to the bottom of the U at its center line, and the wall thickness of the 1~, i . e . the difference between the said two radii) will, of course, depend on the size of the tire in which the reinforcement member is incorporated and on the stresses to which it will be subjected in use. As a matter of general design, however, it is contemplated the dimensions of each single-body single-turn reinforcement in-tended for use in a tire of a given rim size or bead diameter should be such as to provide such reinforcement with a metal surface area equal to ~pproximately 50% o the metal surface area of a conven-tional multiple-wire multiple-turn bead core bundle intended for use in a correspondingly sized conventional tire. It will be apparent, therefore, that the ~ead reinforcements 31 and 32 are considerably smaller in volume and less bulky than conventional multiple-turn multiple-wire bead core bundles.
It will also be understood that the use of such small bead reinforcements in the form of solid, single-turn, single-body end-less metal members in lieu of the conventional multiple-turn mul-tiple-wire bead core bundles is rendered possible by the confluence of a number of different factors. One of these is the fact that the bead reinforcements 31 and 32 of the present invention will gen-erally no t be subjected, during the manufacture of the tire 21, during the mounting or demounting of the tire on the drum 22, and when the tire is in use, to the types of distortions and flexural stresses to which conventional bead wire cores are subjected. In this regard, moreover, it will be understood that the formation of the reinforcements with a substantially U-shaped cross-section through the provision of the longitudinal or circumferential channels in their outer surfaces entails two additional advantages. On the one hand, the presence of the upstanding la~eral wall portions bounding the channel, i.e. the legs sf the ~, ensures that the metal members have sulficient bearn s~rength and stiffness (re-sis~ance to flexure) to withstand, with an adequate margin of safety, such stresses as they will be subjected to during handling as well as in use. On ~he other hand, the absence of material represented by the channels not only does not have an adverse effect on the strength and stiffness of the reinforcements but at the same time enables the weight of the reinforcements to be re-duced as much as possible. Merely by way of example, whereas a conventional rubber-impregnated bead wire core bundle for a 13-inch bead diameter tire would weigh on $he order of about 5.5 ounces, a bead rein~orcement according to the present invention would have a weight of about 2 ounces, which constitutes a weight saving of well over 60%.
S~ill others of the various factors which render the use of the small bead reinforcements of the present invention possible are the ~act that the tire has a low height ratio and the act that the ring members 37 and 38, due to their adhesion to the beads and lower sidewall regions of the tire, aid the bead reinforcements in sup-porting the inflation forces encountered in the bead areas. At the same time, by virtue of the fact that the bead reinforcements of the present invention are considerably smaller in bulk or volume than the conventional bead wire core bundles, not only the beads 29 and 30 themse]ves but also the correspondiny bead seat sections 37a/38a and bead restraining flange sections 37b/38b of the ring men-lbers 37 and 38 may be made considerably smaller than they would have to be in a conventional tire/wheel combination. Merely by way of example, in a typical 13-inch bead diameter tire according to the present invention, the widths of the bead feet 29a/30a and oE the bead seat portions 37a/38a of the ring members, and ~he heights of the bead sides 29d/30d and of the bead restraining flange portions 37b/38b of the ring members, denoted by the respective dimensions s and f in Fig . 3, are 0.450 inch and 0.350 inch, respectively .
Both of these dimensions are substantially less than the dimensions of corresponding elements of conventional tires and wheel rims.

The presence of smaller beads in the tires means of course, that the tires contain smaller quantities of rub~er in the beads and the contiguous lower regions of the sidewalls. As a consequence, the weight of the tires and therethrough the overall weight of the 5 vehicle on which the tires are mounted are materi~lly reduced with respect to corresponding conventional tires. Another advantage accruing from the present invention is, therefore, the fact that the amount of energy consumed in driving a vehicle riding on tire/drum combinations according to the present invention is correspondingly 10 reduced.
Merely in passing it should be noted that although bead rein-forcements having the semicircular channeled cross-sectional con-figurations illustrated and so far described herein are preferred, the bead reinlorcements may have slightly different cross-sectional 15 configurations within the basic concepts of the present invention.
Thus, the inner surfaces 31a/32a and the outer longitudinal channels 31c/32c of the reinforcements need not be precisely of semicircular curvature but could be otherwise arcuate (parabolic, hyperbolic, etc. ) . The legs of the U may also have free end 2û sections that are linear, i . e . non-circular, and preferably parallel extensions of the circularly curved portions. The overall cross-sectional configuration could even be generally crescent-shaped, i . e . with the channel having a somewhat greater radius of curva~
ture than the inner sur~ace of the reinforcement member and with 25 the wall thickness of the reinforcement cross-section as a conse-quence not being uniform throughout from one not necessarily flat lateral edge to the other. It would also be possible for the channel to be in the form of a narrow groove or even omitteà altogether.
As a still further alternative, the inner surface of the bead rein-30 forcement may even have at least one generallv flat circumferentialportion, although in such a case it would be preferred for the lateral boundaries of any such portion to be rounded. It will be unclerstood, however, that such an arrangement too is to be con-sidered an arcuate surface configuration within the concept ol the 35 present invention. In any event, the herein disclosed semicircular configuration is preferred primarily ~ecause this is a good contour for the purposes of the tire building and shaping operations, in -2û-that it makes ~or a smooth fitting and rotation o~ the tire body plies around the reinforcemen~s while a~ the same time prov~ding an absence of relatively sudden directional changes for the portions o~
the plies passing about the reinforcements.
S As yet another refinement of the present invention, it is contemplated that the radially inwardmost sections of the apex or filler strips 35 and 36 will be contoured in accordance with the contours of the outer surface of the reinforcements. Thus, where the bead reinforcements are provided with outer channels, such as 31c/32c, the apex strips in a corresponding fashion would be pro-vided with peripheral projecting ribs matched to extend into the channels, thereby to provide a `oetter interlock between the apex strips and the bead reinforcements during the tire building and shaping operations as well as in the finished tire.
Reverting now to the ring members 37 and 38, i~ will be under-stood that the manner of attachment thereof to the drum 22, which can best be comprehended frorn Figs. l, 2 and 4 to 9, should be such as to fulfill certain specific objectives of the present in-vention. Principally, of course, the attachment system must serve to ensure the proper location of the ~ire 21 on the drurn and rela-tive to the vehicle axle. The attachment system must also be such as to render and maintain the tire/drum combination fully airtight under all anticipated normal conditions of use, and it must be su~ficiently sturdy to withstand the severe stresses to which it will be subjected while the tire is in service. Still further, the attach-ment system should be simple enough to permit the tire to be readily mounteA on and demounted from the drum without entailing the imposi tion, during such operations, of any undue stresses on and deformations o~ the beads 29 and 30 and the bead reinforce-ments 31 and 32. Finally, in somewhat of a contradiction to the aforesaid simplicity, it is contemplated that the attachment system, because of the uniqueness of the tire/drum com'oination of the present invention and the complete departure of its cs~nstruction from that of the heretofore conventional tire and wheel arrange-ments, should nevertheless also be so construct~d as to inhibit its dismantling without the use of special tools.

n~

With the foregoing objectives kept in mind, it will be seen that the attachment system for the inboard ring member 37 is relatively simple. Basically, the ring member 37 has an overall con~iguration matched to that of the flange section 25 of the skirt 22b of the 5 drum 22 ~see Figs. 1 and 2). Thus, ~he said flange section has a portion 25a corresponding to the bead seat section 37a of the ring member 37, a portion 25b corresponding to the bead restraining flange section 37b, a portion 25c corresponding to the lower side-wall supporting section 37c, and a peripheral extension 25d cor-10 responding to the peripheral extension 37d The only Rifferencebetween the two configurations is that, whereas the taper angle of the bead seat defining section 37a of the ring member 37 is about 5 to the axis of the tire, the taper angle of the portion 25a of the skirt flange section 25 is about 15 to the axis OI the ~ire, as a 15 result of which a small generally wedge-shaped space is formed between the ring member 37 and the skirt 22b at the region of juncture therebetween when the ring melrber is mounted on the drwn .
Referring now also to Figs. 8 and 9, it will be seen that the 20 attachment means which enable the ring member 37 to be securely fastened to the drum 22 include the peripheral extension 37d of the ring member and the extension 25d of the skirt flange section 25, the respective sets of circumferentially distributed openings or bores 40 and 41 formed therein, and the associated fasteners in the 25 form of bolts 42 and nuts 43. It will be understood, of course, that the actual number of paired openings 40/41 and bolt and nut combinations 42/43 that will be required to effect a secure attach-ment of the ring member 37 to the drum 22 may vary for tires of different sizes and different intended conditions of use and hence 30 will be selected as desired, but it is contemplated that preferably at least about ten and possibly as many as a dozen or more such fastening means should be employed as a minimum. lt will also be apparent that the precise form of the fastening mechanism may likewise be varied as desir ed . Merely by way of example, in ~he 35 illustrated embodiment thereof the openings 40 in the ring member extension 37d as well as the heads of the bolts 42 are square in outline, while the bores 41 in the flange section extension 25d and ~ ~ f ~ ,b the threaded shanks ~f the bolts are circular in outline, so $hat the bolts 42, the shanks of which are suf~iciently long to extend through the flange section extension 25d, can be prevented rom rotating while the respective nuts 43 are tightened agains$ the.
underside of the extension 25d.
By way of contrast to the Ioregoing, the a~tachn ent system for the outboard ring member 38 is somewhat more complex. Referring now more particularly to Figs. 4 to 7 in conjunction with Figs. 1 and 2, it will be seen that the outboard ring member 38, in addition 10 to the sections 38a to 38d already descr~bed, has a circumferential laterally inwardmost portion in the form of a plurality of projecting parts 44 adapted to closely overlie a circumferential radially out-wardmost portion 45 of the drum body 22a. Each of the projecting parts 44 is provided with a respective opening 46, and correspond-15 ingly the drum body portion 45 is provided with a plurality Df openings 47. The drum body is further provided with a plurality of struck-out parts 48 which are ben~ up to overlie the radially outwardmost portion 45 of the drum body. Each of ~he struck-out parts 48, the number of which is equal to the number of projecting 20 parts 44 on the outboard ring member 38, is provided ~Ath an opening 49 aligned with the respective opening 47 in the drum body portion 45. On i~s inboard side ~he drum body 22a is further provided with a plurality of bushings 50 which are welded or other-wise permanently secured to the drum body and have respective 25 internally threaded bores 51 which are aligned with the openings 47 and 49. The openings 46, 47 and 49 are dimensioned to accommo-date freely the threaded shank of a suitable bolt 52, which is adapted lo extend through each set of such openings and be tightly screwed into the bores 51 of the bushings 50.
The manner of attaching the outboard ring member 38 to the drum 22 will best be comprehended from Figs. 6 and 7. As clearly shown in F'ig. 6, the circumferential widths of the spaces between struck-out parts ~8 of the drum body 22a are ~omewhat laryer than the circumferential widths of the projecting parts 44 of the outboard 35 ring member 38. At the same time, the spaces or gaps ~etween the bent up struck-out parts 48 of the drum body and the radially outwardmost portion ~5 of the drum body which they overlie are sufficient to accommodate the thickness of the projecting parts 44 of the outboard ring member. To connect the latter to the drum, therefore, the said projecting parts are first introduced into the spaces between the struck-ou~ parts of the drum body ~Fig. 6) and the ring member is then rotationally displaced, for example in the direction of the arrow shown in Fig. 6, to shift ~he projec~ing parts 44 into the respective spaces between the struck-out parts 48 and the radia~ly outwardmost portion 45 of the drum body. This opera-tion is continued until the openings 46 are aligned with the open-ings 47 and 49 and the bores 51 (Fig. 7). When the ring member 38 has reached this position, the bolts 52 are screwed in~o ~he bushings 50 and ~ightened against the outermost surfaces of the struck-out parts 48. Here ~oo it will be understood that, as in the case of the inboard ring member, the number of sets of associated struck-out parts, projecting parts, bushings and bolts can be varied as desired, depending on the strength of ~he connection re~uired, bu~ again it is contemplated that preferably at least ten and possibly as many as twelve or more such fastening means should be utilized.
The manner in which a tire 21, having a pair of inboard and outboard ring members 37 and 38 adhered thereto, is mounted on and attached to a drum 22 will now be described. For the purposes of this description, it should be noted, it is assumed that the drum has already been itself mounted on a vehicle axle hub 23 and se-- 25 curely fastened ~hereto by means of bolts 23a, but it will be under-stood that the tire could be mounted on and attached to the drum fi,st while the lat~er is held in a suitable fixture or jig off the v hicle, with the entire combination then being transferred to the vehicle. The term "vehicle axle-borne drum" as used herein should, therefore, be interpreted as denoting a drum which either is or subsequently will be secured to a vehic]e axle hub.
As the first step of the operation, then, two circumferentially continuous strip- or layer-shaped quantities 53 and 54 of a suitable sealant, preferably a sealing compound of any of $he hereinbefore referred to types disclosed by U. S. Patents Nos. 3,981,342, 4,012,567 and 4,064,922, are applied to the outer surface of the drum 22, one at the inboard region where the skirl: 22b merges into -~4-the portion 25a of the flange section 25, and one at the region of juncture between the outboard end of the skirt and the radially outwardmost portion 45 of the drum body 22a. Thereafter, the tire 21, w~th the inboard ring member leading, is fitted over the skirt 5 portion 22b of the drum in the direction of the arrow shown in Fig.

2, until the sections 37b, 37c and 37d of the ring member 37 lie fully on the corresponding portions of the flange section 25 of the drum skirt and the ring member section 37a presses tightly against the quantity of sealant 53 at the portion 25a of the drum skirt.
10 The fitting of the inboard ring member over the drum skirt is, of course~ greatly facilitated by the fact that the skirt tapers, albeit at a relatively shallow angle of about 3 to the tire axis from the flanged inboard end to the unflanged outboard end of the drum, thus being somewhat narrower at the outboard end. During this 15 stage of the operation, of course, care must be taken that the tire is being manipula~ed so as to have the projecting parts 44 of the outboard ring member 38 lined up wi~h the circumferen~ial spaces between the bent up struck-out parts 48 of the drum body 22a.
When the inboard ring member is seated against the skirt flange 20 section ~'5, th~refore, the openings 40 and 41, though in circum-ferential alignment, will be out of vertical registry with each other, as shown in Fig. 8, to an extent corresponding to the then ex~sting off-sets between the openings 46 and 49.
Once this condition has been attained, the outboard sidewall 28 25 of the tire is pushed inboardly until the projecting parts 44 of the outboard ring member are received in the spaces between ~he struck-oul parts 48 and are pressed against ~he quanti~y of sealant 54, with the projecting par~s circumferentially aligned with the gaps between ~he drum body portion 45 and the struck-out parts 48.
30 The tire is then rotation~lly ~lisplaced, in the direction of the arrows shown in Fiys. 6 and ~, to bring lthe projec~ing parts 44 into the said gaps or spaces behind the struck-out parts 48, this movement being continued until the openings 46 come into alignment with the openings 47/49 and the bore 51, at which time the open-35 ings 40 in the inboard ring member extension 37d will likewise havecome into vertical registry with the openings 41 in ~he skirt flange extension 25d. The respective bolts 42 and 52 can then be fitted through their respective sets of a3igned holes and tightened in place, in the one case by the affixation oi the nuts 43 onto the bolts 42 and in the other case by the screwing of the bolts 52 into the bores 51, thereby to securely anach ~he ring members to the 5 drum. The tightening of the ring members 37 and 38 in place is, of course, effected with at least some of the respective quantities of sealant being confined between the ring members and the drum, while the remaining portions of the sealant lie outside these regions of confinement but still along the respective regions of juncture 10 between the ring members and the drum, as shown in Fig. 1. The interior oI the ~ire is thus rendered fully airlight, with no possi-bility of air ~osses occurring past the rin~ members.
As previously mentioned, it is contemplated by the present in-vention that, although ~he mounting procedure described is rela-15 tively simple, it should be sufficiently difficult to discourage itsbeing attempted by any person (including the driver) no~ equipped with special tools. It is to this end that the bolts 23a and 52 both are shown as being provided, for example, with internally hexa-gonal heads (Figs. 6 and 7) requiring special tools for their manipu-20 lation. Thus, in the event of the tire 21 becoming punctured anddeflated, the motorist will normally not be able to demount the flat ~ire and replace it by a spare. Rather, he or she ~ill be forced to proceed to the nearest service station for the perIormance of such repairs as will be necessary. Such a course of conduct would, of 25 course, be very likely to create severe difficulties in the case of an ordinary tire/wheel combination having substantially no run-flat capabili ty, since in that case, if the vehicle were to be driven a considerable distance with the tire flat, either the tire or the wheel rim or both could be substantially ruined and rendered completely 30 unfit for further use. Thus, the ability to change a flat tire (i.e.
to replace it with a spare tire) is an almost absolute necessity in the case of a vehicle-riding on conventional tire/wheel combinations.
A tire/drum combination according to the present invention is not so restricted, however. Thus, since by virtue of its adhesion to 35 the ring members and the fastening of the latter to the drum, the tire 21 cannot become separated from the ring members, the tire/
drum combination according to the present invention does possess a ~ J~ 'J_~,f~1 substantial run-~lat capability and could be driven for considerable distances at reasonable speeds without risking ruination of either the tire or the drum.
Rever~ing now to the mounting operation described aboYe, once 5 that operation has been completed and the tire is securely mounted, it is necessary to inflate the tire to the desired operating pressure.
To this end the present invention contemplates the provision of a novel valving system for the tire which avoids the needs ~Dr the inclusion of a standard tire inflation valve in the outboard ring 10 member. Such valves, as has been mentioned previously, fre-quently lead to air losses from the tire, which may take place either through the valve itself because of dirt or some mechanical defect therein or through the hole in the wheel rim in which the valve is mounted .
Referring now more particularly to Fig. 10, the valving system according to the present invention by which this problem is effec-tively overcome includes, in the illustrated form, a small depression or embossment 55 in the outboard ring member 38, the bottom of which depressi~n is directed outwardly of the tire. A small hole 56 20 provided in the bottom of the depression 55 constitutes a passage-way which is open both at the inside surface and at the outside surface of the ring mernber. The depression contains a quantity of sealant 57, pref~rably the same sealant as is used to seal the regions of juncture between the ring members and the drum, which 25 is in direct contact with the ring member surface and completely covers the opening 56. The depression is located intermediate on the one hand the zone of adhesion between the bead 30 and the riny member 38 and on the other hand the region where the ring member 38 adjoins the outer peripheral portion of the drum 22. It 30 will be undersLood, in this regard, that the quantity of sealant 57 could be applied separately to the interior oE the depression 55 at the same ~ime as the quantities of the sealant 53 and 54 are applied to the outer surface of the drum. Alternative]y, it would also be possible ~o avDid this separate step and to utilize the ~uantity of 35 sealant 54 to cover the opening in the bottom of the depression, which could be done by making this quantity of sealan ~ sufficient that when the outboard ring me!nber is pressed against the drum -27~ r3 some of the sealant would be forced to flow into the depression 55 and thereby to cover the opening 56. In any event, it will be apparent that the sealant will thereafter prevent any. flow o:f air through the opening 56, while inflation of ~he tire can be effected 5 very simply by extending an inflation needle 58, having an air outlet opening 59 at one end and connected to an air hose 60 at its other end, through the opening 56 and the quanti~y of sealant 57.
Upon insertion of the needle through the sealan~ (Fig 11) the same will flow closely around the needle and escape of air will not be 10 possible, while upon completion o~ the inflation operation and with-drawal of the needle (Fig. 12), the sealant will be drawn into the hole previously formed by the needle so as to seal the same as fully as if it had never existed.
As previously mentioned, one of the principal objectives of the 15 present invention is the provision of an optimized construction of the tire/drum combination. To this end it is contemplated by the present invention to establish ~ertain relations between the dimen-sions g, h and R of the tire and the dimension j of the moun~ing system (all of which dimensions are shown in Fig. 1) and hence to 20 establish certain relations between as well as value ranges for the aspect ratio ~, the height ratio ~ and the ring width ratio ~ .
These ratios are represented by ~e equations = hlg.
0 = h/R, and ~ = i/g.
where g is the distance, in a direction parallel to the tire axis, between the most widely separated portions of the sidewalls of the tire; h is the radial dimension o~ the tire as measured from the toe ring diameter Lo a line parallel to the tire axis and tangent to the 30 outer surface o~ the tread at its apex (i.e. where it is intersected by the median equatorial or mid-circum~erential plane of the tire); j is the distance, in a direction parallel to the tire axis, between the outer extremities o~ the adhesion ~ones, i . e . between the laterally outwardmost ends of the sidewall-supporting extensions 37c and 35 38c, of the inboard and outboard ring members; and R is the radial distance ~rom the axis of the tire to the aforesaid line tangent to the tread at its apex. For the purposes of the present invention, the aspec~ ratio, the height ratio and the ring width Fa~io conform substantially lo the relations )~ _ O . 236 o . 32 G ~ ~ o . 39, and ~= 1~ ~ , 10 and with the height ratio at its maximum being lower than the minimum height ratio of conventional P-metric tires ~0.40 and above to more than 0.50~, an aspect ratio as low as 0.60 or so and in any event lower than about 0 . 74 can be achieved . In this regard, it should be noted that, ~or ~he purposes of the present invention, 15 the value of ;~ (the aspect ratio) characterizing the tire need not lie precisely on the curve represented by a plot of ;~ against ~ in accordance with the first two of the above relations, but could deviate therefrom to a limited degree, say to the extent of about +5%, and the term "conform substantially" as used herein with 20 respect to the aspect ratio should, therefore, be interpreted as embracing a deviation of this magnitude. The existence and main-tenance of these relations, in conjunction with the other physical characteristics OI the tire/drum combination hereinbefore described, enables a minimization of stresses in the sidewalls to be achieved 25 along with ~ood tire performance ~wear resistance, Iatigue resis-tance, ride and handling), a reduction in tire weight for a giver load-carrying capacity, the ability to use a single ply carcass having low ply turn-ups around lighter and thinner bead reinforce-ments, and the ability to eliminate the usual spare tire altogether.
It will be understood that the foregoing description of pre-ferred embodiments of the present invention is for purposes of illustration only, and that the various structural and operational features herein disclosed are susceptible ~o a number of modifi-cations and changes none of which entails any departure from the 35 spirit and scope of the present invention as defined in the hereto appended claims.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A pneumatic tire which has a generally toroidal shape defining a circumferential crown region, a tread overlying the crown region, and a pair of sidewalls extending generally radially inwardly from the tread and terminating in a pair of circumferential interiorly reinforced beads:
characterized in that two ring members constituting parts of a mounting system for the tire and each defining a respective bead seat, an associated bead restraining flange and an associated side-wall-supporting extension from the latter are adhered to the tire at the inboard and outboard sides of the tire, respectively, the zone of adhesion in each case extending over the surface of the foot and the outer side of the respective bead and thence over the surface of the portion of the associated sidewall located just radially out-wardly of and contiguous to that bead, and each of said ring mem-bers being constructed and arranged for releasable attachment thereof to a vehicle axle-borne drum constituting another part of the mounting system for the tire.

2. A pneumatic tire which has a generally toroidal shape defining a circumferential crown region, a tread overlying the crown region, a pair of sidewalls extending generally radially in-wardly from the tread and terminating in a pair of circumferential interiorly reinforced beads, a reinforcing carcass underlying the tread and sidewalls of the tire, the carcass including a ply of tire cords disposed in substantially radial planes of the tire and ex-tending from one bead to the other, the opposite end regions of the ply being turned up around the interior reinforcements of the beads, and a tread-reinforcing belt of tire cords underlying the tread in the crown region of the tire; characterized in that:
(a) two ring members constituting parts of a mounting system for the tire and each defining a respective bead seat, an associated bead restraining flange and an associated sidewall-supporting extension from the latter are adhered to the tire at the inboard and outboard sides of the tire, respectively, the zone of adhesion in each case extending over the surface of the foot and the outer side of the respective bead and thence over the surface of the portion of the associated sidewall located just radially outwardly of and contiguous to that bead;
(b) the turned-up portions of said carcass ply terminate within the respective zones of adhesion between said exten-sions of said ring members and said portions of the associated sidewalls, thereby to ensure the absence of any mechanical discontinuities in the portions of the sidewalls subject to flexure during operation of the tire; and (c) each of said ring members is constructed and arranged for releasable attachment thereof to a vehicle axle-borne drum constituting another part of the mounting system for the tire.

3. A pneumatic tire as claimed in claim 1 or 2, character-ized in that, when the tire is mounted with its beads confined between said bead restraining flanges and it is in an inflated, unloaded state, the height ratio .theta. = h/R and the aspect ratio .lambda. =
h/g of the tire conform substantially to the relation wherein 0.32<.theta.<0.39, R is the radial dimension of the tire from its axis to a first line parallel to the axis and tangent to the outer tread surface at the apex of the crown region, h is the radial dimension of the tire from a second line parallel to the axis and constituting the toe ring diameter of the tire to said first line, and g is the distance, in a direction parallel to the axis, between the most widely separated portions of the two sidewalls.

4. A pneumatic tire as claimed in claim 1 or 2, character-ized in that when the tire is mounted with its beads confined between said bead restraining flanges and with its lower sidewall portions contiguous to said beads supported by said extensions, and when the tire is in an inflated, unloaded state, the height ratio .theta. = h/R, the aspect ratio .lambda. = h/g and the ring width ratio ? = j/g of the tire conform substantially to the relations wherein 0.32<.theta.<0.39, R is the radial dimension of the tire from its axis to a first line parallel to the axis and tangent to the outer tread surface at the apex of the crown region, h is the radial dimension of the tire from a second line parallel to the tire axis and constituting the toe ring diameter of the tire to said first line, g is the distance, in a direction parallel to the tire axis, between the most widely separated portions of the two sidewalls, and j is the distance, in a direction parallel to the tire axis, between the outer extremities of said extensions.

5. A pneumatic tire as claimed in claim 2, character-ized in that the interior reinforcement of each bead is a single metal member in the form of a single loop having an inner and an outer surface and no free ends, said inner surface of said metal member in cross-section being convexly arcuate.

6. A pneumatic tire as claimed in claim 5, characterized in that each said bead reinforcement has a surface area equal to about 50% of the surface area of a conventional multiple-wire multiple-turn bead wire core bundle for reinforcing the beads of a conventional tire of corresponding toe ring diameter.

7. A pneumatic tire as claimed in claim 5, characterized in that each said metal member has a circumferential channel formed therein at said outer surface thereof.

8. A pneumatic tire as claimed in claim 7, characterized in that said inner surface and said channel of each said metal member each has a semicircular curvature in cross-section.

9. A pneumatic tire as claimed in claim 8, characterized in that said inner surface and said channel of each said metal member are cross-sectionally concentric with one another, each said metal member thereby having a uniform cross-sectional thickness.

10. A pneumatic tire as claimed in claim 1, character-ized in that the outer surface of the portion of each of said side-walls located just radially outwardly of and contiguous to the respective head in said zone of adhesion and said extension of the associated ring member to which that sidewall surface portion is adhered are inclined at an angle of about 25 to the axis of the tire.

11. A pneumatic tire as claimed in claim 10, character-terized in that the surface of the foot of each bead from its toe to its heel in said zone of adhesion and the bead seat portion of the associated ring member to which that bead foot surface is adhered taper radially inwardly of the tire at an angle of about 5° to the axis of the tire.

12 . A pneumatic tire as claimed in claim 11, characterized in that the outer surface of the portion of each of said sidewalls located just radially outwardly of and contiguous to the respective bead in said zone of adhesion and said extension of the associated ring member to which that sidewall surface portion is adhered are inclined at an angle of about 25° to the axis of the tire.

13. A pneumatic tire as claimed in claim 12, character-terized in that an apex strip is incorporated in the portion of each sidewall located just radially outwardly of and contiguous to the respective bead, each said apex strip extending from its associated metal member and terminating beyond said zone of adhesion but radially inwardly of the widest portion of the tire section.

14. A pneumatic tire as claimed in claim 13, characterized in that each said apex strip terminates at a line parallel to the axis of the tire and located in the region between 1/4 and 1/3 of the height of the tire section as measured from a line which is parallel to the tire axis and constitutes the toe ring diameter of the tire to a line which is parallel to the tire axis and is tangent to the outer surface of the tread at the apex of the crown region.

15. A pneumatic tire as claimed in claim 1 or 2, charac-terized in that the outboard one of said ring members is provided with a depression having its bottom directed outwardly of the tire and located intermediate said zone of adhesion and the portion of that ring member where the same adjoins the vehicle axle-borne drum when attached thereto, said outboard ring member being further provided with a small hole in the bottom of said depression, and said depression being adapted to contain a quantity of a sealant having self-sealing properties, the depression and the sealant when the same is contained therein thereby constituting a valving system for the tire adapted to permit inflation of the tire by insertion of a hollow inflation needle through said hole and said quantity of sealant.

16. In combination, a pneumatic tire which has a generally toroidal shape defining a circumferential crown region, a tread overlying the crown region, and a pair of sidewalls extending generally radially inwardly from the tread and terminating in a pair of circumferential interiorly reinforced beads, and a mounting system for the tire;
characterized in that the mounting system includes:
(a) a drum having a body adapted to be secured to the hub of a vehicle axle, and a peripheral skirt secured to said body and extending therefrom in the inboard direction of the vehicle when the drum is properly mounted on the hub of the vehicle axle, said skirt being provided at its inboard lateral boundary with a circumferential flange section and being devoid of any flange section at its outboard lateral boundary;
(b) two ring members each defining a respective bead seat, an associated bead restraining flange and an associated side-wall-supporting extension of the latter are adhered to the tire at the inboard and outboard sides of the tire, respectively, the zone of adhesion in each case extending over the surface of the foot and the outer side of the respective bead and thence over the surface of the portion of the associated side-wall located just radially outwardly of and contiguous to that bead, and the inboard one of said ring members having con-tours corresponding substantially to those of said flange sec-tion of said skirt;
(c) first attachment means releasably secure the inboard one of said ring members to said skirt along said flange section;
(d) second attachment means releasably secure the outboard one of said ring members to said drum body adjacent the outboard lateral boundary of said skirt, said outboard ring member being contoured to dispose the outboard bead seat, bead restraining flange and sidewall-supporting extension defined by said outboard ring member at locations relative to the axis of the tire corresponding to the locations of the inboard bead seat, bead restraining flange and sidewall-supporting extension defined by said inboard ring member;
and (e) respective quantities of a sealant having self-sealing properties are located at the circumferential regions of junc-ture between said ring members and said skirt for rendering the interior of the tire airtight.

17. In combination, (A) a pneumatic tire which has a generally toroidal shape defining a circumferential crown region, a tread overlying the crown region, a pair of sidewalls extending generally radially inwardly from the tread and terminating in a pair of circum-ferential interiorly reinforced beads, a reinforcing carcass under-lying the tread and sidewalls of the tire, the carcass including a ply of tire cords disposed in substantially radial planes of the tire and extending from one bead to the other, the opposite end regions of the ply being turned up around the interior reinforcements of the beads, and a tread-reinforcing belt of tire cords underlying the tread in the crown region of the tire, and (B) a mounting system for the tire;
characterized in that the mounting system includes:
(a) a drum having a body adapted to be secured to the hub of a vehicle axle, and a peripheral skirt secured to said body and extending therefrom in the inboard direction of the vehicle when the drum is properly mounted on the hub of the vehicle axle, said skirt being provided at its inboard lateral boundary with a circumferential flange section and being devoid of any flange section at its outboard lateral boundary;
(b) two ring members each defining a respective bead seat, an associated bead restraining flange and an associated side-wall-supporting extension of the latter are adhered to the tire at the inboard and outboard sides of the tire, respectively, the zone of adhesion in each case extending over the surface of the foot and the outer side of the respective bead and thence over the surface of the portion of the associated side-wall located just radially outwardly of and contiguous to that bead, and the inboard one of said ring members having con-tours corresponding substantially to those of said flange sec-tion of said skirt;
(c) first attachment means releasably secure the inboard one of said ring members to said skirt along said flange section;
(d) second attachment means releasably secure the outboard one of said ring members to said drum body adjacent the out-board lateral boundary of said skirt, said outboard ring mem-ber being contoured to dispose the outboard bead seat, beat restraining flange and sidewall-supporting extension defined by said outboard ring member at locations relative to the axis of the tire corresponding to the locations of the inboard bead seat, bead restraining flange and sidewall-supporting extension defined by said inboard ring member; and (e) respective quantities of a sealant having self-sealing properties are located at the circumferential regions of junc-ture between said ring members and said skirt for rendering the interior of the tire airtight;
and further characterized in that in the tire the turned-up portions of said carcass ply terminate within the respective zones of adhesion between said sidewall-supporting extension of said ring members and the portions of the associated sidewalls juxtaposed thereto, thereby to ensure the absence of any mechanical discon-tinuities in the portions of the sidewalls which are located radially outwardly of said supported sidewall portions and are subject to flexure during operation of the tire.

18. The combination claimed in claim 17, characterized in that in the mounting system said outboard ring member is provided with a depression having its bottom directed outwardly of the tire and located intermediate said zone of adhesion and the portion of that ring member where the same adjoins said drum, said outboard ring member being further provided with a small hole in the bottom of said depression, and said depression containing a further quan-tity of a sealant having self-sealing properties, said depression and said further quantity of sealant contained therein thereby constitut-ing a valving system for the tire adapted to permit inflation of the tire by insertion of a hollow inflation needle through said hole and said further quantity of sealant.

19. The combination claimed in claim 18, characterized in that in the mounting system said first attachment means include a circumferential laterally outwardmost portion of said inboard ring member contiguous with said inboard sidewall-supporting extension and having a plurality of openings therein, a circumferential lateral-ly outwardmost portion of said flange section of said skirt closely underlying said laterally outwardmost portion of said inboard ring member and having a plurality of openings therein each correspond-ing to a respective one of said openings in said laterally outward-most portion of said inboard ring member, and a plurality of fasten-ing members extending through the respective associated ones of said openings in said laterally outwardmost portions of said inboard ring member and said flange section of said skirt and tightly secur-ing the same to one another.

20 . The combination claimed in claim 19, characterized in that in the mounting system said second attachment means includes a circumferential radially outwardmost portion of said body of said drum having a plurality of openings therein, a circumferential laterally inwardmost portion of said outboard ring member closely overlying said radially outwardmost portion of said drum body and having a plurality of openings therein each corresponding to a respective one of said openings in said radially outwardmost portion of said drum body, and a plurality of fastening members extending through the respective associated ones of said openings in said laterally inwardmost portion of said outboard ring member and said radially outwardmost portion of said drum body and tightly securing the same to one another.

21. The combination claimed in claim 20, characterized in that in the mounting system said drum body has a plurality of circum-ferentially spaced struck-out parts each located radially inwardly of said radially outwardmost portion of said drum body and bent up to overlie a respective one of said openings in that portion of said drum body at a spacing therefrom sufficient to accommodate said laterally inwardmost portion of said outboard ring member, each of said struck-out parts having a respective opening therein, said laterally inwardmost portion of said outboard ring member including a plurality of projecting parts each received in a respective one of the spaces between said struck-out parts and said radially outward-most portion of said drum body, and each of said fastening members extending through a respective associated set of said openings in said struck-out parts, said projecting parts and said radially out-wardmost portion of said drum body.

22. The combination claimed in claim 21, characterized in that in the mounting system the circumferential spaces defined between adjacent ones of said bent up struck-out parts of said drum body are somewhat greater than the circumferential widths of said pro-jecting parts of said laterally inwardmost portion of said outboard ring member, thereby to enable said projecting parts to be fitted into said circumferential spaces and then introduced into the spaces between said radially outwardmost portion of said drum body and said struck-out parts of the latter by means of a rotational dis-placement of said tire relative to said drum.

23. The combination claimed in claim 16 or 17, characterized in that the outer surface of the portion of each sidewall of the tire within said zone of adhesion and said extension of the associated ring member of the mounting system to which that sidewall surface portion is adhered are inclined at an angle of about 25° to the axis of the tire.

24. The combination claimed in claim 16 or 17, characterized in that the surface of the foot of each bead of the tire from its toe to its heel within said zone of adhesion and the bead seat portion of the associated ring member of the mounting system to which that bead foot surface is adhered taper radially inwardly of the tire at an angle of about 5° to the axis of the tire.

25. The combination claimed in claim 16 or 17, characterized in that in the mounting system said skirt tapers radially inwardly at an angle of about 3° to the axis of the tire from said inboard flange section to the outboard lateral boundary of said skirt where the same adjoins said body of said drum.

26 . The combination claimed in claim 16 or 17, characterized in that:
(a) the outer surface of the portion of each sidewall of the tire within said zone of adhesion and said extension of the associated ring member of the mounting system to which that sidewall surface portion is adhered are inclined at an angle of about 25° to the axis of the tire;
(b) the surface of the foot of each bead of the tire from its toe to its heel within said zone of adhesion and the bead seat portion of the associated ring member of the mounting system to which that bead foot surface is adhered taper radially inwardly of the tire at an angle of about 5° to the axis of the tire; and (c) said skirt of the mounting system tapers radially inwardly at an angle of about 3° to the axis of the tire from said in-board flange section to the outboard lateral boundary of said skirt where the same adjoins said body of said, drum.

27. The combination claimed in claim 16 or 17, characterized in that the height ratio .theta. = h/R and the aspect ratio .lambda. = h/g of the tire when the same is in an inflated, unloaded state conform sub-stantially to the relation wherein 0.32<.theta.<0.39, R is the radial dimension of the tire from its axis to a first line parallel to the axis and tangent to the outer tread surface at the apex of the crown region, h is the radial dimension of the tire from a second line parallel to the axis and constituting the toe ring diameter of the tire to said first line, and g is the distance, in a direction parallel to the axis, between the most widely separated portions of the two sidewalls,.

28. The combination claimed in claim 16 or 17, characterized in that the height ratio .theta. = h/R, the aspect ratio .lambda. = h/g and the ring width ratio ? = j/g of the tire and drum when the tire is in an inflated, unloaded state conform substantially to the relations wherein 0.32<.theta.<0.39, R is the radial dimension of the tire from its axis to a first line parallel to the axis and tangent to the outer tread surface at the apex of the crown region, h is the radial dimension of the tire from a second line parallel to the tire axis and constituting the toe ring diameter of the tire to said first line, g is the distance, in a direction parallel to the tire axis, between the most widely separated portions of the two sidewalls, and j is the distance, in a direction parallel to the tire axis, between the outer extremities of said sidewall-supporting extensions of said inboard and outboard ring members.

29. The combination claimed in claim 17, characterized in that the interior reinforcement of each bead of the tire is a single metal member in the form of a single loop having an inner and an outer surface and no free ends, said inner surface of said metal member in cross-section being convexly arcuate.

30. The combination claimed in claim 29, characterized in that each said metal member has a surface area equal to about 50% of the surface area of a conventional multiple-wire multiple-turn bead wire core bundle for reinforcing the beads of a conventional tire of cor-responding toe ring diameter.

31. The combination claimed in claim 30, characterized in that each said metal member has a circumferential channel formed therein at said outer surface thereof.

32. The combination claimed in claim 31, characterized in that said inner surface and said channel of each said metal member each has a semicircular curvature in cross-section.

33. The combination claimed in claim 32, characterized in that said inner surface and said channel of each said metal member are cross-sectionally concentric with one another, each said metal mem-ber thereby having a uniform cross-sectional thickness.

34. The combination claimed in claim 29, characterized in that an apex strip is incorporated in the portion of each sidewall of the tire located just radially outwardly of and contiguous to the respec-tive bead, each said apex strip extending from the associated interior reinforcement of that bead and terminating beyond said zone of adhesion but radially inwardly of the widest portion of the tire section, the radially inwardmost end region of each said apex strip being lcoated at and mated to said associated interior rein-forcement.

35. A pneumatic tire as claimed in claim 34, characterized in that each said apex strip terminates at a line parallel to the axis of the tire and located in the region between 1/4 and 1/3 of the height of the tire section as measured from a line parallel to the tire axis and constituting the toe ring diameter of the tire to the apex of the tread.

36. A mounting system for mounting a pneumatic tire on a vehicle axle; the mounting system being characterized in that it includes:
(a) a drum having a body adapted to be secured to the hub of a vehicle axle, and a peripheral skirt secured to said body and extending therefrom in the inboard direction of the vehicle when the drum is properly mounted on the hub of the vehicle axle, said skirt being provided at its inboard lateral boundary with a circumferential flange section and being devoid of any flange section at its outboard lateral boundary;
(b)two ring members each defining a respective bead seat, an associated bead restraining flange and an associated side-wall-supporting extension of the latter, said ring members being adapted to be adhered at said bead seats, said bead restraining flanges and said sidewall-supporting extensions to the corresponding outer surfaces of the respective inboard and outboard beads and sidewalls of the tire, and the inboard one of said ring members having contours corresponding substan-tially to those of said flange section of said skirt;
(c) first attachment means for releasably securing the inboard one of said ring members to said skirt along said flange sec-tion; and (d) second attachment means for releasably securing the out-board one of said ring members to said drum body adjacent the outboard lateral boundary of said skirt, said outboard ring member being contoured to dispose the outboard bead seat, bead restraining flange and sidewall-supporting extension defined thereby at locations relative to the axis of the tire corresponding to the locations of the inboard bead seat, bead restraining flange and sidewall-supporting extensions defined by said inboard ring member.

37. A mounting system as claimed in claim 36, characterized in that said outboard ring member is provided with a depression located intermediate said outboard bead seat and the portion of that ring member which adjoins said drum when that ring member is secured to said drum, said outboard ring member being further provided with a small hole in the bottom of said depression, and said depression being adapted to contain a quantity of a sealant having self-sealing properties, said depression and said quantity of sealant when contained therein thereby constituting a valving sys-tem for the tire adapted to permit inflation of the tire by insertion of a hollow inflation needle through said hole and said quantity of sealant.

38. A mounting system as claimed in claim 36, characterized in that said first attachment means include a circumferential laterally outwardmost portion of said inboard ring member contiguous with said inboard sidewall-supporting extension and having a plurality of openings therein, a circumferential laterally outwardmost portion of said flange section of said skirt adapted to closely underlie said laterally outwardmost portion of said inboard ring member and having a plurality of openings therein each corresponding to a respective one of said openings in said laterally outwardmost portion of said inboard ring member, and a plurality of fastening members adapted to extend through the respective associated ones of said openings in said laterally outwardmost portions of said inboard ring member and said skirt flange section for tightly securing the same to one another.

39. A mounting system as claimed in claim 38, charac-terized in that said second attachment means include a circum-ferential radially outwardmost portion of said body of said drum having a plurality of openings therein, a circumferential laterally inwardmost portion of said outboard ring member adapted to closely overlie said radially outwardmost portion of said drum body, and a plurality of fastening members adapted to extend through the re-spective associated ones of said openings in said laterally inward most portion of said outboard ring member and said radially out-wardmost portion of said drum body for tightly securing the same to one another.

40. A mounting system as claimed in claim 39, characterized in that said drum body has a plurality of circumferentially spaced struck-out parts each located radially inwardly of said radially outwardmost portion of said drum body and bent up to overlie a re-spective one of said openings in that portion of said drum body at a spacing therefrom sufficient to accommodate said laterally in-wardmost portion of said outboard ring member, each of said struck-out parts having a respective opening therein, said laterally inwardmost portion of said outboard ring member including a plurality of projecting parts each adapted to be received in a re-spective one of the spaces between said struck-out parts and said radially outwardmost portion of said drum body, and each of said fastening members being adapted to extend through a respective associated set of said openings in said struck-out parts, said pro-jecting parts and said radilaly outwardmost portion of said drum body.

41. A mounting system as claimed in claim 40, characterized in that the circumferential spaces defined between said bent up struck-out parts of said drum body are somewhat greater than the circumferential widths of said projecting parts of said laterally inwardmost portion of said outboard ring member, thereby to enable said projecting parts to be fitted into said circumferential spaces and then introduced into the spaces between said radially outward-most portion of said drum body and said struck-out parts of the latter by means of a rotational displacement of said outboard ring member relative to said drum.

42. A mounting system as claimed in claim 36, characterized in that said sidewall-supporting extension of each ring member is in-clined at an angle of about 25° to the axis of said drum.

43. A mounting system as claimed in claim 36, characterized in that said bead seat of each ring member tapers radially inwardly of the drum at an angle of about 5° to the axis of the drum.

44. A mounting system as claimed in claim 36, characterized in that said skirt tapers radially inwardly of said drum at an angle of about 3° to the axis of said drum from said inboard flange section to the outboard lateral boundary of said skirt where the same adjoins said body of said drum.

45. A mounting system as claimed in claim 36, characterized in that:

(a) each of said sidewall-supporting extensions of said ring members is inclined at an angle of about 25° to the axis of said drum;
(b) each of said bead seats of said ring members tapers radially inwardly of said drum at an angle of about 50 to the axis of said drum; and (c) said skirt tapers radially inwardly at an angle of about 3°
to the axis of said drum from said inboard flange section to the outboard lateral boundary of said skirt where the same adjoins said body of said drum.