Resilient tires and wheels – Tires – resilient – Cushion and pneumatic combined
Reexamination Certificate
2000-11-01
2003-07-29
Johnstone, Adrienne C. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Cushion and pneumatic combined
C152S520000
Reexamination Certificate
active
06598633
ABSTRACT:
BACKGROUND OF INVENTION
The present invention concerns vehicle tire safety supports that are mounted inside the tires, on their rims, in order to carry the weight in case of tire failure. In particular, it concerns the connection between those safety supports and the rims on which they are mounted.
The main function of the safety supports is to carry the weight in case of severe loss of inflation pressure of the tire. When tires are inflated normally, the safety supports should interfere with the dynamic properties of the tires as little as possible. In particular, they should remain well centered around the rim in order to avoid any unbalance effect, whatever the temperature of the support and the traveling speed of the vehicle. They should also be capable of being mounted on the rims of vehicle wheels and demounted easily.
U.S. Pat. No. 5,690,762 relates to a safety support made of an elastic material designed to be mounted on a well-base rim of an ordinary passenger vehicle. This support contains a body and a base designed to come in contact with the rim. The support further includes annular reinforcements circumferentially oriented and appreciably inextensible, the radius of which is slightly greater than the radius of the flange of the rim for which the support is provided. The base consists of two annular zones, whose inner radius in free state is less than that of the part of the rim on which they must bear; the compression of these annular zones therefore ensures good centering of the support on the rim. The function of the annular reinforcements is, notably, to prevent the annular zones from stretching, by reason of high-speed centrifugal forces, until losing contact with the rim.
When a safety support is designed to equip a rim in two parts or a rim possessing a bearing for a support, the radius of which is greater than that of one of the rim flanges, as shown in
FIG. 1
, the safety support is mounted by insertion of the support on the corresponding rim bearing. One can refer to U.S. Pat. No. 5,836,366 which describes a method of mounting an assembly made up of a tire and tread support on such a wheel rim bearing. It is important for the support to be well centered on the rim bearing while maintaining easy mounting and demounting, as well as satisfactory endurance.
On the other hand, when annular reinforcements are necessary to withstand centrifugal forces, the annular reinforcements can be placed in the base. This is the case with the support disclosed by application EP 0,796,747 A1. Such a position of the annular reinforcements facilitates the manufacture of the support.
For such a support, taking into account the manufacturing tolerances of the rim and support, it is no longer possible to use radially inner annular zones, the compression of which ensures good centering on the rim, whatever the speed, while ensuring easy mounting and demounting.
“Equatorial plane” of a safety support is understood to be any plane perpendicular to the axis of rotation of the support and “mid-equatorial plane” is understood to be the equatorial plane placed in the middle of the support.
The “axial plane” of a support or wheel is understood to be any plane passing through the axis of rotation of the support or wheel.
SUMMARY OF THE INVENTION
According to a first aspect, the object of the invention is a safety support designed to be inserted by a relative translation operation on a wheel rim bearing, said support having an axially front face and an axially back face and containing a base intended to fit around said bearing as well as a body connected to said base, said bearing having an engagement edge and said translation operation consisting of moving the engagement edge of the rim bearing of said axially front face of the support toward said axially back face, characterized in that the radially lower surface of the support presents a plurality of circumferentially distributed centering protuberances, each of said centering protuberances possessing in section through an axial plane at least one portion of a radially inner profile, whose distance from the axis of the support gradually diminishes in the axial direction between a value exceeding the radius of the engagement edge of the rim bearing on the front side of the support and a value less than that radius toward the back side of the support, in order to permit a friction engagement between the rim and the support.
The presence of the centering protuberances makes it possible to bring about their compression with extension of the support upon its insertion around the rim bearing. This ensures good centering of the support in relation to the rim. The particular shape of said protuberances further makes it possible to transform them into actual guides of the support, which markedly facilitates mounting on the bearing, notably, in the zone of the support where, by reason of the thickness of the protuberance, mounting results in a compression of the latter.
According to a second aspect, the invention concerns a similar safety support in which each of said centering protuberances possesses in section through an axial plane at least one radially inner profile portion, whose distance from the axis of the support gradually diminishes in the axial direction between a value exceeding the radius of the engagement edge of the rim bearing on the back side of the support and a value less than that radius toward the front side of the support.
This second characteristic is particularly advantageous. It markedly facilitates demounting of the support by preventing the edges of the protuberances from being stopped against any part of the rim that the protuberance must pass.
The invention also concerns a similar safety support designed to be inserted by a relative translation operation around a rim bearing, said support containing a base intended to fit around said bearing, as well as a body connected to said base, said body containing suitable zones for defining cavities separating the base and the radially outer part of the support and distributed around the support, characterized in that the radially inner surface of said base of the support presents a plurality of circumferentially distributed centering protuberances, and in that at least some of said protuberances are radially arranged internally opposite corresponding cavities in said body.
This arrangement has the advantage of limiting the variations of radial stiffness of the support as a function of the azimuth and, consequently, upon running on support, of diminishing the variations of forces sustained by the support, as well as the vibrations produced by the protuberances. This results in an appreciable improvement of endurance of these supports in operation.
According to an additional aspect, an object of the invention is a safety support of the general type in which the base contains a zone of resistance appreciably inextensible circumferentially, but flexible, the radially inner radius of which is slighter greater than the radius of the rim support bearing, as well as means for centering the support relative to the rim. This support is characterized in that the centering means consist of a plurality of circumferentially distributed protuberances radially arranged internally relative to the zone of resistance of the base and the radially inner walls of which are inscribed in free state on a radius less than the radius of the rim support bearing.
The protuberances radially arranged internally relative to the zone of resistance generate, by their radial compression, tightening stresses on mounting of the support, but also have the advantage of making possible a polygon formation of the zone of resistance that is flexible and very slightly extensible. Said polygon formation makes it possible to absorb some variation of radius of the rim support bearing or of the zone of resistance and thus ensure easy mounting of the support, while maintaining excellent resistance to centrifugal force.
The protuberances are preferably arranged symmetrically in relation to the axis of rotation of the supp
Drieux Jean-Jacques
Lacour Jean-Charles
Pompier Jean-Pierre
Baker & Botts LLP
Johnstone Adrienne C.
Michelin & Recherche et Technique S.A.
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