ENSEMBLE PNEUMATIQUE/JANTE DE SECURITE

SAFETY TYRE AND WHEEL RIM ASSEMBLY

Abrégé anglais

ABSTRACT FOR CASE DM 5620/5625 Cognate
A safety tyre and wheel rim assembly having a safety support
member comprising a plurality of arcuate segments of rigid
material coupled together at their ends and mounted in a channel-
shaped bearing ring mounted on the wheel rim wherein the bearing
ring is located against both tyre beads to retain them in position.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:-
1. A safety tyre and wheel rim assembly comprising:
a pneumatic tyre having a tread, sidewalls and beads, a
wheel rim having a pair of bead seats and between the bead
seats a substantially uniform diameter, a safety support
member to act as a load carrying member in the event of
tyre deflation, the safety support member comprising a
plurality of arcuate segments of rigid material coupled
together by means of coupling portions at their ends, a
bearing ring of rigid material having a channel shape in
cross-section, providing a bearing in which the support
member is rotatably mounted, and locating means contacting
both tyre beads to locate the bearing ring axially of the
assembly and retain the tyre beads in position.
2 A safety tyre and wheel rim assembly according to
claim 1 wherein the bearing ring is divided about a radial
plane within the smaller diameter bearing surface of the
channel section so that the bearing ring may be assembled
onto a pre-assembled or partly pre-assembled support member.
3. A safety tyre and wheel rim assembly according to
claim 1 or 2 wherein the bearing ring comprises two or more
segments interconnected end-to-end.
4. A safety tyre and wheel rim assembly according to
claim 1 or 2 wherein the locating means comprise shoulder
portions one either side of and integral with the bearing
ring to contact the tyre beads.
5. A safety tyre and wheel rim assembly according to
claim 1 wherein the locating means comprises a pair of spacer

rings one either side of the bearing ring.
6. A safety tyre and wheel rim assembly according to
claim 5 wherein the spacer rings are of resilient material.
7. A safety tyre and wheel rim assembly according to
claim 6 wherein the resilient spacer rings are of rubber.
8. A safety tyre and wheel rim assembly according to
claim 1 wherein a coating of low friction material is
provided between the bearing ring and the support member.
9. A safety tyre and wheel rim assembly according to
claim 8 wherein the coating comprises a P.T.F.E. layer on
the bearing ring.

Description

This invention relates to safet~ tyre and wheel rim
assemblies incorporating an annular safety support member
intended to become load bearing if the tyre becomes deflated.
Such safety support members are described in U.K.
Patent Specification ~o. 1,375,415. The support member may
be of rigid plastics or metal such as aluminium alloy and is
preferably formed by interconnected segments. -~
According to the present invention a safety tyre and
wheel rim assembly comprises a pneumatic tyre having a tread,
sidewalls and beads, a wheel rim having a pair of bead seats
and between the bead seats a substantially uni~orm diameter,
a safety support member to act as a load carrying member in
the event of tyre de1ation, the sa~ety support member
comprising a plurality o~ arcuate ~egments o~ rigid material
coupled together by means of coupling portions at their ends,
a bearing ring of rigid material having a channel shape in
cross-section, providing a bearing in which the support member
i5 rotatably mounted, and locating means contacting both ~yre
beads to locate the bearing ring axially o~ the assembly and
retain the tyre beads in position.
The pneumatic tyre in the assembly may be of the
tubeless type and of either cross-ply or radial construction.
The bearing ring may be divided about a radial plane
within the smaller external bearing diameter so that the
bearing ring may be assembled onto a pre-assembled or partly
pre-assembled support member. The bearing ring may also
comprise two or more segments for interconnection in the
same manner as the support member. Preferably the segments
2-

are the same in length and number as the segments of the
support member.
The locating means may be integral shoulders provided
either side of the bearing ring or may be separate spacer
rings. The spacer rings may be of resilient material for ~
example rubber and may be solid or incl~de voids. Preferably,
however~ the spacer rings are sufficiently hard to prevent ~.
bead dislodgement.
A!low friction coating may be applied to the bearing
surface of the bearing ring, for example a P.T.F.~. coating,
or alternatively a lubricant may be applied on assembly. A
low friction material may also be provided at the surface of
the ~upport member contacting the tyre.
Furthermore, a degree of resilience may be provided
in the ~afety ~upport member by means of including a la~er or ....
layers of resilient material in the outer periphery or on the
inner periphery of the tyre.
. The invention is particularly suited to applications .: -
in the field of truck and military vehicle tyres which may be ..
fitted to rim assemblies having no well and may have a
removable flange ring or be of the split rim type;
Thus the wheel rim may be of the kind having a 15 taper
. on the bead seats in which ca~e the locating means successfully
prevent.bead dislodgement. : . .
~ur.ther aspects of the present invention.will become
,, :
. apparent .from the following description of two embodiments in . .-:
conjunction with the-diagrammatic drawings in.which~
: .
Figure 1 is a part cross-section of ~ tyre and wheel
' ~: ? 3 - :

~34~13
rim of the detachable flange type
according to the present invention, and
Figure 2 is a part cross-section of a split wheel
rim.
The tyre and wheel rim assembly shown in Figure 1
comprises a main wheel rim 1 having a fi.rst retaining flange
2 and bead seats 3 and a locking ring g.roove 4. A detachable
flange 5 having a bead seat 6 is engaged with the main rim 1
and is retained in said engagement by means of a locking ring
7. A sealing ring 8 is provided between the main rim 1 and
the detachable flange 5.
A tyre 9 is located on the bead seats 3 and 6.
A bearing ring assembly 10 i9 fitted between the tyre
beads 11 and 12. The bearing ring 10 comprises two halves 13
and 14 which abut to formja channel shape cross section bearing
member 10. An abutment shoulder 15.is provided on each of the : .
two halves 13 and 14 and the abutments contact the tyre beads ..
11 and 12 and retain them against the flanges 2 and 5.
The inner surface 16 of the channel shape bearing
member 10 has a layer 17 of P.T.F.E. attached to it and a ~ .
safety support member 18 is mounted within the channel so ~.
that i~ runs upon the P.T.F.E. bearing layer 17. .
The safety support member assembly.is as described
in Briti3h Patent ~o. 1,375,415.
~: 25~ The embodiment sh~wn in Figure 2.comprises a split rim -.
., .
formed by two rim halves 19 and 20 held toge.ther by bolts 21 .. :
in conventional manner. A bearing ring 22..is located centrally
on the rim assembly and a pair of separate spacer rings 23 and :
. .

24 are provided one either side of the bearing ring 22 to
provide location for the ring and to retain the tyre beads
25 and 26 against their respective flanges. The spacer rings
are of rubber and are maintained under a degree of pre-
compression by the assembly.
The bearing ring 22 i5 a U-shaped section extending
around the rim and the support member 27 may take any of
the previously mentioned forms.
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