Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Reexamination Certificate
1999-09-15
2003-04-29
Maki, Steven D. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
C152S375000, C152S379300, C152S379500, C152S400000, C301S095104
Reexamination Certificate
active
06554036
ABSTRACT:
BACKGROUND OF INVENTION
The present invention relates to tires. In particular, it concerns the mounting and demounting of a tire casing on and off a rim, and it also concerns, consequently, the mounting and demounting of tire casings on a vehicle, for example, for their replacement.
It is known that the development of wheels equipped with tires has led to a trend in design which, at present, consists of making the wheel easily demountable from the vehicle, the tire being removable from the wheel in an operation carried out at the shop with specialized machines. As is well known, the wheel is demountable from the hub of a vehicle usually by unscrewing a set of bolts. The wheels, the rims and the beads of a tire casing are covered by manufacturing standards which dictate the outer shapes and dimensions of those parts (see, for example, the ETRTO in Europe).
Most wheel and tire assemblies are made according to the principle just mentioned. This is the case with almost all equipment for passenger vehicles. It is also the case with most equipment for trucks, construction machinery, fanning or logging equipment, etc. As far as the largest dimensions are concerned, for example, to equip construction machinery or earth movers, the assemblies are built according to comparable principles, except that the rim is generally made in several parts assembled by a large number of bolts. This corresponds to a tire casing section having the general appearance of a horseshoe (“&OHgr;”) open on the side of the axis of rotation of the tire, which proves simpler to manufacture than other types of sections (see, for example, the closed toroidal tire); the manufacturing facilities available have been developed and optimized for this type of tire. The open “&OHgr;” shape is also appreciated because it makes it possible to inspect the inside of the casing and affords access to the inside of the casing in order to repair it, if necessary.
The present state of the art is the result of a technological evolution which, in the course of time, has been directed at offering tire and wheel assemblies which are as easy as possible to mount on and demount from the vehicle. Thus, the solution proposed for passenger vehicles makes possible the removal of the wheel and tire assembly from the hub simply enough to be within the ability of the ultimate user.
There have been very few technological developments in the course of the past decades concerning the principle of mounting a tire casing on the wheel and the principle of mounting the wheel on a vehicle. In some specific applications, such as wheel and tire assemblies for racing cars (like the Formula 1), in order to be able to mount and demount the equipment as quickly as possible, a center attachment wheel is used, making it possible to fasten the wheel to the hub of the vehicle very rapidly. But this type of fastening requires the use of very specific tightening and loosening wrenches, which are not available in most machine shops. The problem of wheel and tire equipment mounting and demounting time also arises for truck fleets or for construction equipment.
In the course of the specification, the expression “tire casing” is reserved for the object having two sidewalls attached to a crown part having a tread, the two sidewalls each ending radially inward in a bead. This is the commercial product as commonly manufactured nowadays. The part indeformable to working stresses, on which the tire casing is mounted, is called a “rim”, the beads serving to position the tire on the seats of a rim. A “wheel” includes a rim and the means for mounting that rim on a hub, which is, for example, usually a wheel disk. As used herein, a “tire” is an assembly constituting a toroid delimiting a tight chamber that can be inflated to the normal working pressure provided for by the designer. A tire casing mounted on the rim is one of the possible ways of making a tire (in the meaning given to the word “tire” hereabove).
However it is made, the mounting of a tire casing on a rim consists of positioning the beads on the rim seats and against the rim flanges. Each rim seat requires centering (radially) and generally presents a slight conicity making possible a degree of tightening of the casing, when the bead is axially displaced toward and up to the flange, which requires of it an axial positioning relative to the fastening surface of the wheel on the hub of the vehicle. In other words, the rim seats can be considered positioning the beads relative to the axis of rotation of the rim, while the rim flanges position the bead relative to a reference perpendicular to the axis of rotation of the rim. In addition to the function of imposing a geometrically precise position for the bead of the tire casing, the rim seat and the rim flange also have the function of ensuring tightness between the rim and the tire casing, and have the function of making it possible, through sufficient tightening of the tire on its rim, to transmit a torque between the rim and the tire casing.
SUMMARY OF THE INVENTION
The object of the present invention is to simplify radically the mounting and demounting of a tire on and off the vehicle it equips. According to one aspect of the present invention, the mounting and demounting of a tire casing or of a tire on and off the rim supporting it do not necessitate a specialized mounting machine, like those making it possible to have the flange of the rim crossed by the beads of the tire casing, nor the tightening or loosening of a large number of bolts. The invention proposes a solution which makes it possible to fit a tire on a support that it will be convenient to call “rim” (because it is a support not deformable on working stresses) in a very simple manner: a simple relative transverse displacement between tire and rim suffices, the tire and rim remaining with merged axes during the relative translation movement.
The invention proposes a toroidal tire including, as seen in mounted position on a suitable rim:
a mounting base on the rim, said base forming a sleeve extending crosswise and being capable of forming a closed toroid defining a tight chamber, said base constituting the radially innermost wall of said toroid;
said base being intended to be mounted on the rim; securing means for axially opposing any relative movement of the tire on the rim at least in one of the two directions, said securing means being:
arranged on the radially inner face of the base;
designed to cooperate with a complementary bearing arranged on the rim in order to oppose any relative movement between tire and rim axially in the said direction at least;
arranged in a part of the base which presents a degree of flexibility between a relaxed natural position and a position radially stressed outward, in which those securing means are free of any engagement with the said complementary element, said part of the base and the securing means being so shaped and constituted that, when said chamber is at the same pressure as the atmospheric pressure prevailing outside the chamber, the securing means are engaged with the complementary element, so that the tire will be automatically secured in at least said one direction on the rim, release of the securing means requiring subjecting the latter to the action of outside means serving to make said securing means take said position stressed radially outward.
Depending on the applications, the “securing means” can take many different forms, some of which gives them the shape of a localized mechanical locking element, and others a more spread out shape. One designates here means which contribute to oppose any relative movement of the tire on the rim and which contribute to the security of the immobilization of the tire on its rim. Let us note also that the so-called “relaxed natural” position of the securing means can be different from the one they have when they are engaged with the complementary bearing of the rim, the latter (engaged position) generally being an intermediate position between the relaxed natural position and the position stressed radially out
Baker & Botts L.L.P.
Compagnie Générale des Etablissments Michelin & Cie
Fischer Justin
Maki Steven D.
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