Method and apparatus for assembling tire and wheel and filling inner pressure

A method for assembling a tire on the rim of a wheel and filling inner pressure in the tire. The wheel is fixed on a wheel table in an airtight manner to the table. The tire is arranged on the wheel and a pawl is moved along the circumference of the wheel or the wheel on the table is rotated to arrange the bead portions of the tire around the rim of the wheel. An outer cylinder member is brought into abutment against one of the bead portions to urge it toward the other bead portion and pressurized air is filled into the tire through a clearance between the wheel and the one bead portion of the tire to bring the bead portions into close contact with the rim of the wheel. Thereafter, pressurized air is further filled in the tire through the inflation valve of the wheel to maintain the inner pressure higher than the normal inner pressure and then the inner pressure is lowered to the normal inner pressure.

BACKGROUND OF THE INVENTION 
This invention relates to a method and an apparatus for assembling a tire 
on the rim of a wheel without damaging the bead portions of the tire and 
the inside and the outer circumferential surface of the wheel, while at 
the same time filling the tire with inner pressure. 
An apparatus for assembling a tire on the rim of a wheel has been known as 
disclosed in Japanese Utility Model Application Laid-open No. 50-104,302. 
With this prior art apparatus, the wheel is arranged on a table vertically 
movable and fixed thereat by means of an extensible and contractible 
center cone inserted into the hub hole formed in the center of the wheel. 
The tire is then arranged on the wheel so that part of one bead portion of 
the tire is loosely arranged around the well of the wheel. By rotating 
revolving arms coaxially provided on the center cone, bead portions of the 
tire are radially outwardly expanded by guide rollers provided on the 
outer ends of the revolving arms, and at the same time a side surface 
rubber of the tire is urged downwardly by restraining rollers also 
vertically movably provided on the revolving arms. As a result, the bead 
portions of the tire are arranged around the wheel. 
On the other hand, an inner pressure filling apparatus was disclosed in 
Japanese Utility Model Application Laid-open No. 64-16,404, in which one 
bead portion of a tire mounted on the rim of a wheel is urged from the 
side not being fixed toward the other bead portion to form a clearance 
between the bead portion and the wheel, through which clearance 
pressurized air is supplied into the tire. 
In assembling a tire on a wheel by the use of the apparatus of the prior 
art described above, however, the bead portions of the tire are subjected 
to excessive external forces to be unduly deformed. The deformed bead 
portions detrimentally affect the close contact between the wheel and the 
bead portions to lower the tire uniformity and sealing performance so that 
the inherent performance of the tire mounted on the wheel could not be 
exhibited. In the worst case, moreover, there is often a risk of the 
deformed bead portions being damaged in assembling the tire on the wheel. 
On the other hand, with the inner pressure filling apparatus of the prior 
art, the bead portions of the tire are simultaneously brought into close 
contact with bead seats of the wheel. In order to obtain forces to cause 
the bead portions to closely contact the bead seats, it is therefore 
required to make higher the inner pressure of the tire than the normal 
inner pressure. For example, the inner pressure should be 4 to 6 
kgf/cm.sup.2, when the normal inner pressure is 3 to 5 kgf/cm.sup.2. 
Moreover, as the table together with the wheel arranged thereon is rapidly 
lowered in order to fill the inner pressure into the tire with high 
efficiency, the bead portions are abruptly urged against the rim of the 
wheel. Therefore, the deformed bead portions of the tire are undesirably 
mounted in the deformed state on the bead seats of the wheel. 
In addition thereto, in the case that tire is assembled on the wheel and 
then filled with the inner pressure according to the prior art, a tire-rim 
assembling apparatus and an inner pressure filling apparatus must be 
separately provided. Therefore, wide spaces are required, which are 
occupied by such apparatuses. Consequently, a tire-wheel assembling and 
inner pressure filling apparatus has been expected which can effect the 
two operations at one position and is compact in construction. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a method for assembling a tire 
on a wheel and an apparatus for carrying out the method, which can arrange 
the bead portions of the tire around the rim of the wheel without causing 
any undue deformation of bead portions of the tire and bring the bead 
portions into uniformly close contact with the rim of the wheel with 
relatively slight forces by successively filling inner pressure into the 
tire. 
In order to accomplish this object, the method for assembling a tire and a 
wheel and filling inner pressure in the tire according to the invention, 
comprises steps of holding and fixing onto a wheel table the wheel whose 
one end surface is held in an airtight manner, arranging the tire on the 
free end remote from the wheel table so that part of one of bead portions 
of the tire is loosely arranged around the rim of the wheel, arranging a 
pawl of tire mounting means between the wheel and the one bead portion of 
the tire, rotating any one of the pawl and the wheel table supporting 
thereon the wheel relative to the other to relatively move the pawl along 
the circumference of the wheel so that the bead portions of the tire are 
progressively radially outwardly expanded to arrange the bead portions 
around the rim of the wheel along all their circumferences, causing an 
annular outer cylinder member extendable and retractable toward and away 
from the tire and having at its forward end an inclined portion for 
filling inner pressure in the tire to abut against the one bead portion of 
the tire arranged around the rim of the tire to form a clearance between 
the wheel and the bead portion, supplying pressurized air into the 
interior of the tire through the clearance between the wheel and the bead 
portion, progressively retracting the outer cylinder member from this 
state away from the tire to bring the bead portions into close contact 
with bead seats of the wheel, injecting pressurized air into the tire 
through the inflation valve of the wheel to hold once the inner pressure 
of the tire higher than the normal pressure, and lowering the inner 
pressure of the tire to the normal pressure. 
Moreover, the apparatus for assembling a tire and a wheel and filling inner 
pressure into the tire according to the invention, comprises a wheel table 
for arranging thereon the wheel on which the tire is assembled, the wheel 
table having rotating means for rotating the wheel table together with the 
wheel thereon, fixing means for holding and fixing on the wheel table the 
wheel whose one end surface is held in an airtight manner, an annular 
outer cylinder member vertically movable and surrounding the wheel table 
to form clearances between the wheel table and the outer cylinder member 
and between the wheel and one of bead portions of the tire, through which 
clearances pressurized air is supplied into the tire, the outer cylinder 
member having at its end an inclined portion to contact the one bead 
portion and urge it toward the other bead portion, tire mounting means 
having a pawl for progressively arrange the bead portions of the tire 
around the rim of the wheel held and fixed to the wheel table, the tire 
mounting means having moving means for moving the pawl substantially in 
vertical and horizontal directions and air injection means for injecting 
pressurized air through an inflation valve of the wheel. 
In a preferred embodiment of the apparatus, the fixing means comprises a 
taper cone having a taper portion to be fitted in the hub aperture of the 
wheel and a through-aperture at the center, a fixing rod to be inserted in 
the through-aperture of the taper cone and having at its front end an 
engaging portion and at the rear end a stopper to contact the taper cone, 
and a block rotatably held through a bearing on the operating end of a 
cylinder arranged on a frame of the wheel table, the block having 
anchoring pieces pivotally connected thereto for embracing the engaging 
portion of the fixing rod inserted in the through-aperture of the taper 
cone. 
The invention will be more fully understood by referring to the following 
detailed specification and claims taken in connection with the appended 
drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIGS. 1a and 1b and FIGS. 2 and 3, a wheel table 1 for 
arranging thereon a wheel W is rotatably supported on a bearing 1b fitted 
on a stationary frame 1a (FIG. 2). The wheel W is held and fixed on its 
one end surface onto the wheel table 1 in an airtight manner through a 
sealing member such as rubber sheet S by means of fixing means 2. The 
fixing means 2 comprises a taper cone 2a (FIG. 4) adapted to be fitted in 
a hub aperture W.sub.1 of the wheel W, a fixing rod 2d having at the front 
end an engaging portion 2b and at the rear end a stopper 2c and adapted to 
be inserted into the through-aperture h of the taper cone 2a, a cylinder 
2e held by and fixed to the stationary frame 1a, and a block 2g rotatably 
held by the rod end of the cylinder 2e through bearings 2f1 and 2f2 to be 
able to be raised and lowered along a guide g (shown as an integral 
construction with a frame of the table 1) by the action of the cylinder 
2e. 
The block 2g includes at least one pair of anchoring pieces 2i rockably 
supported by means of pivot pins 2h. At the uppermost position of the 
block 2g, the anchoring pieces 2i fall down about the pivot pins 2h near 
to their horizontal positions to permit the vertical movements of the 
fixing rod 2d inserted through the through-aperture h of the taper cone 2a 
(refer to the right half in FIG. 2). On the other hand, at the lowermost 
position of the block 2g, the anchoring pieces 2i rise vertically so as to 
lock the vertical movements of the fixing rod 2d to fix the wheel W on the 
wheel table 1 firmly (refer to the left half in FIG. 2). 
An annular outer cylinder member 3 surrounds the wheel table 1 so as to 
form a clearance t with the table 1 (FIG. 3). In filling inner pressure in 
the tire, the outer cylinder member 3 urges upward one bead portion toward 
the other bead portion of the tire to form a clearance t.sub.1 between the 
one bead portion and the wheel (FIG. 10). The outer cylinder member 3 thus 
serves to fill the inner pressure into the tire through the clearances t 
and t.sub.1. For the purpose of urging upward the bead portion of the 
tire, the outer cylinder member 3 is formed at its upper edge with an 
inclined portion 3a and moved upward and downward as a whole by means of 
cylinders 3b, while being kept in an airtight manner with the aid of an 
O-ring. 
Tire mounting means 4 is provided for the purpose of progressively 
arranging the bead portions of the tire around the rim of the wheel W 
fixed to the wheel table 1. The tire mounting means 4 comprises a pawl 4a 
adapted to position between the wheel W and the bead portions of the tire 
for arranging the bead portions around the rim of the wheel, a vertical 
arm 4b of, for example, a spring type for holding the pawl 4a, a first 
pneumatic cylinder 4c for vertically moving the vertical arm 4b together 
with the pawl 4a, and a second pneumatic cylinder 4e held by a tiltable 
arm 4d for horizontally moving the first pneumatic cylinder 4c together 
with the pawl 4a and the vertical arm 4b. Air injection means 5 has a 
nozzle n for injecting pressurized air into the tire through the inflation 
valve (not shown) of the wheel W. 
FIG. 4 illustrates the table 1, the outer cylinder member 3 surrounding it, 
the rubber sheet S, the wheel W, and the fixing means 2, particularly its 
taper cone 2a and the fixing rod 2d to help understanding the relationship 
between these members. 
The procedure for assembling a tire on a wheel and filling inner pressure 
into the tire will be explained hereinafter. 
Referring to FIG. 5, first the tiltable arm 4d of the tire mounting means 4 
is tilted away from the wheel table 1 and a wheel W is arranged on the 
wheel table. The taper cone 2a is then arranged in the hub aperture 
W.sub.1 of the wheel W and the fixing rod 2d is inserted into the 
through-aperture h of the taper cone. The block 2g provided on the rod end 
of the cylinder 2e has been previously raised in its raised position as 
shown in the right half of FIG. 2. When the engaging portion 2b at the 
lower end of the fixing rod 2d has arrived at the anchoring pieces 2i, the 
cylinder 2e is actuated to lower the block 2g to its lowermost position as 
shown in the left half of FIG. 2. 
In this manner, the the fixing rod 2d is lowered at the position where the 
stopper 2c at the upper end of the fixing rod 2d abuts against the taper 
cone 2a. At the moment when the stopper 2c abuts against the taper cone 
2a, the wheel W is firmly fixed to the wheel table 1 whose rotating axis 
is aligned wit the rotating axis of the wheel W. 
Thereafter, the tiltable arm 4d of the tire mounting means 4 is returned to 
the initial vertical position and the first and second pneumatic cylinders 
4c and 4e are actuated to position the pawl 4a to be spaced a 
predetermined distance K (approximately 5 mm) from the edge of the rim 
flange of the wheel W as shown in FIG. 6. The tiltable arm 4d is then 
tilted again and a tire T is arranged on the wheel W fixed to the wheel 
table 1 as shown in FIG. 7. The tiltable arm 4d is then returned to the 
vertical position again and the wheel table 1 is rotated by means of 
driving means (not shown) as illustrated in FIG. 8. 
In this state, the pawl 4a of the tire mounting means 4 is positioned 
between one bead portion b.sub.1 and the wheel W. Therefore, by rotating 
the wheel table 1, the bead portion b.sub.1 is expanded radially outward 
by the pawl 4a so as to be dropped onto the rim of the wheel W over the 
circumference of the bead portion b.sub.1. FIG. 9 illustrates the state of 
the tire T in which the whole bead portion b.sub.1 is loosely arranged 
around the rim of the wheel W. In order to adapt the other bead portion 
b.sub.2 of the tire T onto the wheel W, the wheel table 1 is rotated 
again, while the pawl 4 is maintained in its present position. 
After the tire is loosely mounted on the wheel W in this manner, the 
annular outer cylinder member 3 having the inclined portion 3a at its 
upper edge is moved against the bead portion b.sub.1 of the tire T to form 
a clearance t.sub.1 between the wheel W and the bead portion b.sub.1. 
Pressurized air is then supplied through the air supply tube 3c provided 
on the outer cylinder member 3 to fill the inner pressure into the tire 
through the clearances t and t.sub.1. After the tire has been sufficiently 
filled with the pressurized air, the outer cylinder member 3 is 
progressively lowered as shown in FIG. 11. 
During such operations, as the inclined portion 3a of the outer cylinder 
member 3 is inclined, first the part of the bead portion b.sub.1 
corresponding to the lowest edge of the inclined portion 3a, where contact 
pressure is lowest, rides on the bead seat r of the wheel W and then the 
remaining bead portion b.sub.1 progressively rides on the bead seat r of 
the wheel W. When the inclined portion 3a of the outer cylinder member 3 
has just been out of contact with the bead portion b.sub.1 of the tire T 
as shown in FIG. 12, the whole circumference of the bead portion b.sub.1 
close contacts the bead seat r of the wheel W. 
The difference U (FIG. 12) between the maximum and minimum heights of the 
inclined portion 3a of the outer cylinder member 3 is preferably more than 
10 mm because the width of the bead seat is of the order of 10 mm. 
However, when the outer circumferential length of the inclined portion 3a 
is excessively large, it becomes difficult to fit the bead portion 
uniformly onto the bead seat. Therefore, the difference U is preferably of 
the order of 10 to 20 mm. 
After removing the fixing means 2, the nozzle n of the air injection means 
5 is connected to the inflation valve of the wheel W to fill in the tire 
an inner pressure higher than the normal inner pressure as shown in FIG. 
13. Thereafter, the inner pressure is lowered to the normal pressure to 
complete the operations of assembling the tire and wheel and filling the 
inner pressure in the tire as shown in FIG. 14. 
Although the pawl 4 of the tire mounting means 4 is shown maintained at a 
fixed position and the table 1 is being rotated to arrange the bead 
portion around the rim in the illustrated embodiment, it will be apparent 
that the wheel table 1 may be stationary, while the pawl 4 of tire 
mounting means 4 may be rotated. In this case, however, it may be needed 
to take care to avoid a bulkiness of the apparatus in the vertical 
direction. Moreover, while the wheel table 1 is shown in an integral 
construction in FIG. 3, the upper portion thereof supporting the wheel may 
be separable from its main body, which can provide for wheels and tires of 
various sizes. 
As described above, in assembling a tire and a wheel according to the 
invention, the tire is arranged on the wheel located on the wheel table 1 
and then the wheel table is rotated to arrange the tire bead portions 
around the rim of the wheel. Therefore, it is possible to assemble the 
tire on the wheel without exerting any excessive force onto the bead 
portion so that there is no risk of damage to the bead portions and wheel 
in assembling according to the invention. 
In filling with inner pressure according to the invention, the bead 
portions can be progressively brought into close contact with the bead 
seats of the wheel with the aid of the inclined portion 3a of the outer 
cylinder member 3. Therefore, any high pressure is not needed so that the 
bead portions are not fitted in a deformed state on the rims of the wheel. 
Particularly, even with tires collapsed due to being piled up, they can be 
assembled on wheels and filled with inner pressure with great certainty. 
Moreover, after filling the inner pressure with the aid of such outer 
cylinder member 3, the tire is once kept with the inner pressure higher 
than the normal inner pressure by supplying the pressurized air through 
the inflation valve of the wheel W, with the result that even if the bead 
portions of the tire are not completely uniformly fitted on the wheel, 
they are brought into uniform contact with the bead seats of the wheel 
along all the circumferences of the bead portions. 
Moreover, the apparatus according to the invention is able to fill the 
inner pressure into the tire in the state immediately after having been 
assembled around the wheel, so that the operations for assembling and 
inner pressure filling can be effected in a very short time without 
requiring a widely space occupied by plural apparatuses. The invention 
enables the apparatus for this purpose to be simplified in construction, 
and hence be compacted and easy in maintenance and rugged and durable in 
use. 
In order to confirm the effect of the invention, thirty tires of 195/60R14 
were assembled on wheels of 14-6JJ and filled with inner pressure by the 
use of the apparatus shown in FIGS. 1a and 1b according to the invention, 
respectively and deflections of rim lines of the tires were measured. The 
tires were filled with inner pressure of 0.5 kgf/cm.sup.2 through the air 
supply tube 3c to set the bead portions b.sub.1 and b.sub.2 on the bead 
seats r of the wheels. The inner pressure was then temporarily pressurized 
to 3.0 kgf/cm.sup.2 by supplying pressurized air through the nozzle n, and 
the inner pressure was lowered to the normal pressure of 2.0 kgf/cm.sup.2. 
The results are shown in FIG. 15a in comparison with the results 
illustrated in FIG. 15b whose tires were assembled on wheels and filled 
with inner pressures according to the prior art. Referring to FIGS. 15a 
and 15b, it is clear that the roundness of the tires assembled on the rims 
according to the invention are greatly improved from those of the tires 
assembled by the prior art. 
As can be seen from the above explanation, according to the invention a 
tire can be assembled on a wheel and filled with inner pressure simply and 
rapidly without damaging the bead portions of the tire and the wheel. 
Moreover, the apparatus according to the invention is simple and compact 
in construction without requiring a wide space occupied by the apparatus 
and is inexpensive to manufacture and easy in maintenance. This apparatus 
is particularly very useful as a garage type apparatus for assembling a 
tire and a wheel and filling inner pressure into the tire. 
While the invention has been particularly shown and described with 
reference to preferred embodiments thereof, it will be understood by those 
skilled in the art that the foregoing and other changes in form and 
details can be made therein without departing from the scope of the 
claims.