Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to tire
servicing equipment and more specifically to a device
for seating the beads of a tubeless tire onto the
rims of a wheel.
Machines for servicing tires are generally
well known devices. A typical machine comprises a
mechanical system which clamps the wheel on a supporting
structure and then, a tire changing tool removes or
installs the tire on the wheel. The mechanical system
for clamping the wheel includes a vertical treaded
rod extending through the central opening of the wheel
and receiving a large nut pressing down the wheel
on the supporting structure.
Such tire changing machines are however,
unable to service tires on wheels without a central
opening. Therefore, in the recent years, manufacturers
of tire servicing equiment have developed universal
tire changing machines which operate according to
a different principle. Such machines include a
rotatable table, driven by an electric motor or by
a pneumatic system, and carrying a plurality of movable
clamping jaws which engage the inner wall of the wheel
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to hold it on the table. During a tire servicing
operation, a rotational movement is imparted to the
table while a stationary tire changing tool dismounts
or mounts the tire on the wheel.
During the installation of a new tire, the
first operation is to loosely mount the tire on the
wheel by using the tire changing tool. Subsequently,
compressed air is injected through the valve of the
wheel to seat the tire beads against the rim portions
of the wheel and inflate the tire.
With the increasing popularity of low profile
radial tires with more rigid sidewalls, problems have
been experienced for seating the beads of these tires
to the rims of the wheel. To overcome these problems,
different air injection systems have been designed
to be mounted on the rotatable table for injecting
air through a plurality of discharge noæzles, at a
substantially high pressure, between the interface
of the tire bead and the rim of the wheel, which are
adjacent to the top surface of the table. These systems
however, have not been very successful and their
practical implementation has been rather limited for
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a number of reasons. One of these reasons is that
they are too costly to manufacture and also they are
of such design that they constitute a very tortuous
path for the compressed air, substantially reducing
its pressure at the discharge nozzles.
It is an object of this invention to provide
an improved device for seating beads of a tubeless
tire onto the rims of wheel.
Another object of this invention is a tire
changing machine which comprises an improved device
for seating tire beads of a tubeless tire onto the
rim portions of a wheel.
The device for seating tire beads according
to this invention comprises a header having preferably
an annular shape and attached to the rotating table.
A plurality of conduits, in fluid communication with
the header, extend upwardly therefrom and define air
discharge nozzles at their upper ends, received in
openings drilled in the table. The cross-sectional
area of each conduit, in its upper portion, gradually
and smoothly diminishes toward the discharge nozzle
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to increase the velocity of the air emanating from
the nozzle.
Compressed air is directed from a compressed
air source to the header, through preferably, a flexible
hose having one end permanently connected to the
compressed air source and an opposite end connected
to the header by a quick connect/disconnect coupling.
The header and the conduits define an air
injection system which is free flowing, a relative
term indicating that the air injection system offers
little resistance to the passage of a sudden jet of
a relatively high volume of air therethrough.
During the operation of the device for seating
tire beads, the table should be prevented from rotating
since the header is connected to the flexible hose.
An accidental actuation of the table may tear the
flexible hose resulting in an escape of highly
compressed air and creating a safety hazard for the
operator of the machine.
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09
To prevent an accidental rotation of the
table and consequently of the header which is attached
thereto, the device for seating tire beads includes a
system which disactivates the drive mechanism of the
table when the flexible hose is connected to the
header.
In one embodiment, a holder for the flexible
hose is mounted to the machine and it is provided with
a momentarily acting switch which closes its contacts
when the hose is received in the holder. When the hose
is removed from the holder, the switch assumes its
normal position and opens its contacts. When the table
is driven by an electric motor, the switch may be
connected in series with the electric motor to open the
power supply circuit of the motor when the hose is
removed from the holder.
When the tire changing machine is fully air
operated the switch may be used to control a bleed
valve preventing a build up of pressure in the air
cylinder driving the table. --
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The device for seating tire beads has beendesigned to fit a variety of already existing tire
changing machines. The device may be made available
commercially as a kit including the header to which are
welded the upwardly extending conduits, the hose holder
and the switch to be connected to the drive system of
the table and an instructions manual.
Therefore, the present invention comprises an
assembly for seating beads of a tubeless tire onto the
rims of a wheel, the tire including a pair of spaced
apart beads which are to be seated on corresponding
spaced apart rim portions formed on the wheel, the
assembly being adapted to be mounted on a tire changing
machine of the type comprising a rotatable table
actuated by a driving system, the table having a top
surface on which the wheel is supported, the tire
changing machine further comprising clamp means mounted
on the table and being movable thereon between a wheel
release position and a wheel retaining position wherein
the clamp means firmly engages the inner wall of the
wheel to firmly hold the wheel on the table, the
assembly including
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- a header adapted to be connected to a
source of compressed air, the header being adapted to
be attached to the table at a level below the table;
and
- a plurality of elongated conduits, each
conduit extending upwardly and having an end connected
to the header and an opposite end passing through an
opening in the table and defining an air discharge
nozzle, the air discharge nozzle being adapted to
inject air toward the interface between a bead of the
tire and the corresponding rim portion of the wheel
which are adjacent to the top surface for seating the
wheel.
This invention further comprises a tire
changing machine, including: _
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A
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- a supporting structure;
- a rotatable table comprising a plurality
of openings and being mounted on the supporting
structure, the table having a top surface for supporting
a wheel of a vehicle thereon;
- clamp means mounted on the table and being
movable between a wheel release position and a wheel
clamping position wherein the clamp means is adapted
to firmly engage the inner wall of a wheel to secure
the wheel on the table;
- tire changing tool means mounted on the
supporting structure;
- a device for seating tire beads of a
tubeless tire on the rims of a wheel, the tire including
a pair of spaced apart beads which are to be seated
on corresponding spaced apart rim portions formed
on the wheel during the installation of the tire on
the wheel, the device including:
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a) a header adapted to be connected to
a source of compressed air, the header being secured
to the table at a level below the table; and
b) a plurality of elongated conduits, each
conduit extending upwardly and having an end connected
to the header and an opposite end passing through
an opening in the table and defining an air discharge
nozzle, the air discharge nozzle being substantially
at the level of the top surface and being adapted
to inject air toward the interface between a bead
of the tire and a corresponding rim portion of the
wheel which are adjacent to the top surface for seating
both tire beads on their corresponding rim portions
lS of the wheel, the header and the conduits being f ree
flowing and offering little resistance to the passage
therethrough of a sudden jet of air.
The invention further includes a kit of
a device for seating tire,beads on the rims of a wheel,
the tire including a pair of spaced apart beads which
are to be seated on corresponding spaced apart rim
portions formed on the wheel during the installation
of the tire on said wheel, the device being adapted
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to be mounted on a tire changing machine of the type
comprising a rotatable table which is actuated by
a driving system, the table having a top surface on
which the wheel is supported, the table being provided
S with a plurality of openings, the tire changing machine
further comprising clamp means mounted on the table
and being movable thereon between a wheel release
position and a wheel retaining position wherein the
clamp means firmly engages the inner wall of the wheel
to firmly hold the wheel on said table, the kit of
parts comprising:
- an air injection assembly including:
a) a header;
b) a plurality of upwardly extending
conduits, each conduits having an end secured to the
header and an opposite and defining a discharge nozzle;
and
c) a releasable coupling means mounted
to the header and being adapted to receive an end
of a flexible hose directing air from a source of
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compressed air to the header, the header being adapted
to be mounted to the table at a level below the table,
the nozzles of the conduits being received in the
openings for injecting air toward the interface between
a bead of the tire and the corresponding wheel portion
of the wheel which are adjacent to said top surface
for seating both tire beads on their respective rim
portions of the wheel, the header and the conduits
being free flowing and offering little resistance
to the passage therethrough of a sudden jet of air,
during the operation of the air injection assembly,
the table and the header being immobilized.
A preferred embodiment of this invention
will now be described with reference to the annexed
drawings, in which:
Figure 1 is an perspective view of a tire
changing machine;
Figure 2 i9 a side view of the rotatable
table of the machine shown in figure 1, to which is
mounted an air injection system for seating tire beads
and a wheel and a tire assembly, shown in cross-section;
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Figure 3 is a top view of the rotatable table
shown in Figure 2 some elements being omitted;
Figure 4 is a schematic cross-sectional view
of a holder assembly for carrying a flexible compressed
air hose.
The tire changing machine lO shown in Figure
1, includes a supporting structure 12 from which
extends upwardly a vertical column 14. Column 14
carries at one end thereof a pneumatic tire changing
tool 16, well known in the art. A rotatable table 18
is mounted on structure 12 and comprises a wheel
clamping device 20 actuated by an air cylinder 26. As
it is customary in the art, machine 10 is provided with
a surge tank (not shown) for compressed air fed by a
conventional air compressor. A flexible air hose 25
has one end permanently connected to the tank and it is
used for seating tire beads.
Table 18 is driven by an electric motor (not
shown) operated with foot pedal controls and may be
rotated by the operator clockwise or counterclockwise,
as desired.
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With reference to figures 2 and 3, the wheel
clamping device 20 includes four radially movable
clamps 22 which are mounted on rotatable table 18
and slide in radially extending slots 24.
The tire changing machine 10 includes an
air injection device 36 comprising an annular header
38 from which extend upwardly a plurality of conduits
40, in fluid communication with header 38. Conduits
40 extend upwardly and radially outwardly with respect
to header 38. At a certain level, between header
38 and table 18, conduits 40 make a right angle bend
as at 42, toward table 18. The upper end of each
conduit 40 passes through an opening 44, drilled in
table 18, and defines an air injection nozzle 46,
substantially at the level of the top surface of table
18.
The cross-sectional area of each conduit
diminishes gradually and smoothly, in the upper end
region thereof, toward the nozzle 46 for increasing
the velocity of the air emanating from the nozzle.
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Annular header 38 is mounted below table 18
and it is secured to four brackets 48 (only two being
shown) supporting the table 28 on a rotatable shaft 49
which drives the table.
For certain applications, a polygonal shape
for header 38 is more appropriate since it facilitates
the attachment of the header to the brackets 48
supporting the table.
Compressed air is delivered from the
compressed air tank of the tire changing machine to
header 38 by means of the flexible hose 25 connected to
header 38 by a quick connect/disconnect coupling 52.
Coupling 52, well known in the art, is commercially
available and includes a male member 54 mounted to
header 38 and a female member 56 attached to hose 50.
Such quick release couplings typically comprise a
detent mechanism to hold the female and the male
members interconnected against an unwanted retraction
of the female member 56 from the male member 54.
However, when a sufficient retractive force is applied
to female member 56 to overcome the locking strength of
the detent mechanism, hose 50 will be disconnected from
header 38.~
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A
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Referring to figure 4, a holder assembly
58 for the flexible air hose 25 is mounted to the
tire changing machine 10. The position of the holder
assembly 58 is not critical and the choice of its
location on the machine 10 is governed mainly by
considerations of practical or aestetical nature.
Holder assembly 58 comprises an elbow shaped
conduit 60 comprising a downwardly directed discharge
opening 61 and a nipple 62 adapted to receive the
female membex 56, to which is attached the flexible
air hose 25, of coupling 52. Nipple 62 preferably
comprises a detent mecanism (not shown) to prevent
an unwanted retraction of the female member 56 from
holder assembly 58. Such a detent mecanism is well
known in the art and may comprise a plurality of spring
loaded balls mounted on the female member 56 engaging
an annular groove formed on the outer surface of nipple
62.
Nipple 62 includes an internal cylindrical
opening 64 closed by a steel ball 66 urged toward
an annular ridge 68, formed at the mouth of opening
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64, by a helicoidal spring 70. Spring 70 is held
in place between the steel ball 66 and an annular
protrusion 72 formed within conduit 60.
As an example, nipple 62 may be constructed
from a male member 54 of a coupling 52, which has
been modified to receive spring 70 and steel ball
66 and attached, by any appropriate means to elbow
shaped conduit 60.
A momentariy acting switch 74 is mounted
to the tire changing machine lO, adjacent nipple 62.
Switch 74 comprises an actuator 76, provided at one
end thereof with a roller 78 engaging the female member
56 of coupling 52.
When female member 56 is retracted from
nipple 62, actuator 76 assumes its normal position,
as shown in figure 4, the contacts of switch 74 being
therefore an opened position. When female member
56 is engaged on nipple 62, actuator 76 is pressed
down, closing the contacts of switch 74.
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Switch 74 is connected to the power supply
circuit of the electric motor driving table 18, in
series with the motor.
During the installation of a tire, a wheel of
a vehicle, generally indicated by the reference numeral
100 is mounted on table 18. Clamps 22 are actuated by
the operator to firmly engage the inner wall 28 of
wheel 100.
Table 18 is rotated and a tubeless tire 30 is
loosely mounted on wheel 100 by the tire changing tool
16. To inflate the tire 30, the beads 32 of the tire
must be seated firmly against the rim portions 34 of
the wheel 100 for creating an adequate seal and
preventing air to escape through the interfaces formed
between the beads 21 and their respective rim portions
34 of the wheel. At that end, the operator connects
the hose 25 to the header 38, by means of the quick
connect-disconnect coupling 52 and also connects to the
valve of the wheel a second compressed air line. By
actuating the appropriate controls, air is injected in
the tire by the valve of the wheel and simultaneously a
high pressure air jet is
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toward the interface defined between the tire bead
and the rim portion of the wheel, which are adjacent
to table 18. A quantity of air penetrates within
the tubeless tire 30 so as to create a pressure
differential which will seat both tire beads 32 against
their respective rim portions 34.
During the time hose 25 is connected to
header 38, the contacts of switch 74 are in opened
position, thus disabling the motor driving the table
18 and preventing the latter and the header 38 from
being accidentally rotated. However, when the female
member 56 is mounted on holder assembly 58, the switch
74 closes the power supply circuit of the motor and
allows table 18 to be actuated by the operator.
If an accidental escape of highly pressurized
air occurs, through hose 25, while it is connected
to holder assembly 58, the pressure of the air will
be greatly reduced by the steel ball 66, and the air
will be directed downwardly, through discharge opening
61, reducing the risk of injuries.
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Although the invention has been described
with relation to a specific form, it will be evident
for a person skilled in the art that it may be refined
and modified in various ways. It is therefore wished
to have it understood that the present invention should
not be limited in interpretation except by the terms
of the following claims. .
