Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Reexamination Certificate
2000-01-24
2002-07-16
Johnstone, Adrienne C. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
C152S158000, C152S520000, C152S539000, C152S544000, C152S548000
Reexamination Certificate
active
06418992
ABSTRACT:
BACKGROUND OF THE INVENTION
The object of the present invention is the production of assemblies formed of radial carcass tires and mounting rims, preferably “monobloc” rims, at least some of which may prove useful upon travel when the inflation pressure drops abnormally low as compared with the nominal pressure of use, known as the service pressure, the inflation pressure possibly even becoming zero.
The main difficulties encountered in the case of travel with a flat tire or with low pressure in the tire concern the risks of the unseating of the beads of the tire and, in particular, the unseating of the bead located on the outer side of the tire mounted on the outer side of the vehicle. The well-known techniques proposed in order to avoid such unseatings and, in particular, the one which consists of arranging a hump of small height axially to the inside of the outer rim seat, tend to increase the difficulties in mounting and removing the tires.
One solution which can be applied to the problem of the unseating of beads is that described in French Patent 1139619, which concerns an assembly formed of a tire and a rim which are of such a nature that the flexible edges of the tire, contrary to the usual beads, come, under the effect of the inflation pressure, to grip around rim stops intended to hold said edges spaced from each other. This solution requires a carcass reinforcement which is at least special and not in accord with the compromise of properties required for a modern tire.
Certain prior solutions recommend the addition to a rim, such as described above, of a tread support which is integrated or attached and fastened by any available means. Whether this be with hump or without hump, assemblies which comprise rims with tread supports are known, and German application 36 26 012 and French application 2 560 121 show such assemblies. However, they are not of general use, since, despite the advances made, difficult problems of mounting also arise. The above-mentioned French application describes a method of mounting which makes it possible to eliminate numerous difficulties, namely the swinging and ovalizing of one of the beads of the tire permit the passage of the rim, provided with its tread support within the tire, if said rim is presented with its tread support axis of rotation perpendicular to the axis of rotation of the tire, the beads being then placed on their respective rim seats by means of mounting wells arranged axially on opposite sides of the tread support.
If one designates as S the overall width of the mounting rim measured axially between the ends of the two flanges, D
J
, the diameter of the rim measured at the level of the intersection between the rim flange and the frustoconical generatrix of the rim seat, the latter being seen in meridian section, H′ the height of the prop measured with respect to the parallel to the axis of rotation of the rim passing through said point of intersection, and D
B
the diameter of the bead of the tire, measured on a parallel to the equatorial plane of the tire, which parallel passes through the center of the bead wire, the method described above cannot be applied in the event that the amount 2&pgr;D
B
is less than 2(D
J
+2H′+S), hence the impossibility of having available tires of customary form ratio which have an effective inner tread support.
The difficulties in the mounting and removal of tires mounted on such rims are further accentuated by the introduction of modern tires with lower form ratio and furthermore frequently comprising greatly reinforced beads.
SUMMARY OF THE INVENTION
In general, the object of the invention is to propose other solutions which make it possible to improve the conditions of operation and use of radial carcass tires in case of travel in degraded manner with zero or low pressure, which solutions concern both the tire and the rim as well as the assembly formed by the tire and rim with or without tread support.
For this purpose, in accordance with a first aspect of the invention, a rolling assembly comprising at least one tire with radial carcass reinforcement anchored in each bead to a reinforcement ring and a rim delimited axially by a first rim edge and a second rim edge and provided with a first rim seat and a second rim seat, is characterized by the fact that, seen in meridian section,
a) at least the first rim seat has a generatrix such that the axially outer end of said generatrix is spaced from the axis of rotation by an amount less than the distance from its axially inner end and is delimited axially to the outside by a hump of small height, and by the fact that
b) the tire, mounted on the rim and inflated to its service pressure, is provided with a radial carcass reinforcement having a meridian profile of constant direction of curvature, at least in the sidewall and the bead which are located on the same side of the assembly as the first rim seat.
The first rim seat is inclined towards the outside of the assembly.
The assembly, as described above, advantageously comprises at least one rim flange axially adjacent to one of the rim seats, the maximum diameter of said flange being greater than the diameter of any part of the rim contained between said flange and the edge of the rim axially closest to said flange. At least one mounting well can be provided, said mounting well preferably extending one of the rim seats axially to the inside; or, in the case of the presence of a rim flange, said extension preferably extending said flange axially to the inside.
In accordance with a second aspect of the invention, a rolling assembly comprising a tire with radial carcass reinforcement anchored in each bead to a reinforcement ring, a rim delimited axially by a first rim edge and a second rim edge and provided with a first rim seat and a second rim seat and a tread supporting prop is characterized by the fact that, seen in meridian section,
a) at least the first rim seat has a generatrix such that the axially outer end of said generatrix is spaced from the axis of rotation by an amount less than the distance from its axially inner end, said rim comprising at least one bearing surface intended to receive a tread support having the shape of a ring, said surface being arranged between the axially inner ends of the two seats and having a generatrix the minimum diameter of which, which is the diameter of one of its ends, is at least equal to the diameter of any part of the rim included axially between said end and the rim edge corresponding to the rim seat axially closest to said end, and by the fact that
b) the tire, mounted on the rim and inflated to its service pressure, is provided with a radial carcass reinforcement having a meridian profile of constant direction of curvature, at least in the sidewall and the bead which are located on the same side of the assembly as the first rim seat, and by the fact that
c) the annular tread support is ovalizable, preferably circumferentially unstretchable, and adapted to be placed on the rim bearing surface.
By diameter of the bearing surface there is understood the diameter of the portions of said bearing surface which will be in contact with the tread support.
The assembly, in accordance with this second aspect of the invention, may comprise at least one mounting well, located axially between one of the rim seats and the bearing surface intended to receive the tread support. Further in accordance with this second aspect of the invention, the assembly preferably comprises at least the first rim seat, delimited axially towards the outside by a hump of small height. Likewise, the rim of such an assembly can comprise at least one rim flange axially adjacent to one of the rim seats, the maximum diameter of said flange being greater than the diameter of any part of the rim contained between said flange and the edge of the rim axially closest to said flange. The bearing surface, intended to receive the support, may be a portion of revolution, advantageously adjacent, axially towards the inside, to one of the rim seats, the mounting well bein
Drieux Jean-Jacques
Lacour Jean-Charles
Muhlhoff Olivier
Pompier Jean-Pierre
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