Tire building with bead setting device

In the building of a pneumatic tire on a flat drum or former surrounded by tire plies the beads are positioned intermediate the ends of the former by devices which include fingers having magnets at their leading ends to engage the beads and which are movable axially of the former to displace the beads over the former ends and holders reciprocable relative to the fingers on which the beads are first located, after which the holders and fingers are moved toward the former ends causing retraction of the holders relative to the fingers and displacement of the beads off the holders onto the former by the fingers.

This invention relates to tire building machines and is particularly 
concerned with the provision of a bead-setting device for such a machine. 
Conventionally, a pneumatic tire is constructed on a former, of 
substantially cylindrical shape, and, at the appropriate stage in 
manufacture, the bead wires must be brought on to the former and fitted to 
the tire carcass. Known tire building drums or formers fall broadly into 
two categories. In one the tire beads are brought into abutment with the 
ends of the former, thereby ensuring that they lie in planes to which the 
axis of the former is perpendicular. In the other type, known as a "flat 
former", to which the improvement of the present invention relates, the 
beads are moved a predetermined distance along the former to their final 
positions spaced from the ends of the former and when using a "flat 
former" the problem arise of ensuring that the beads are accurately 
positioned in planes to which the former axis is perpendicular. It is true 
that a flat former is provided with circumferential grooves to receive the 
beads, but these are of no assistance in the initial positioning of the 
beads as at this time the former is surrounded with tire plies which 
extend over the grooves so that the plies on the former present an 
uninterrupted cylindrical surface. A slight error in the initial 
positioning of the beads will not be corrected by their subsequent 
reception into the grooves as the former is expanded, as the beads will 
adhere to the plies before the beads finally locate in the grooves, and 
any subsequent movement of the beads will cause distortion of the plies. 
To locate the beads on a flat former it has been proposed to provide 
axially movable bead-setting devices at each end of the former. The 
operator places the beads on the devices, which may for example, consist 
of a number of circumferentially disposed axially extending fingers 
provided with stops to locate the bead axially. The fingers are moved 
axially inwards to the required position, the former is expanded to grip 
the beads and the holders are then retracted away. Using the type of 
device described above accurate positioning of the beads in planes normal 
to the axis of the former relies on the operator accurately fitting the 
beads on the devices. This is not always easy to achieve and error in 
location can be a major cause of non-uniformity in the finished tire. 
One object of the present invention is to provide a machine having a bead 
setting device which enables the beads to be fitted to a flat former with 
greater accuracy. 
According to one aspect of the present invention there is provided a tire 
building machine comprising a "flat former" (as herein defined), bead 
holder means reciprocable axially of the former into and away from contact 
with each end of the former and of diameter such that when retracted from 
the former a bead may be positioned on the holder means to surround the 
same, and bead location means surrounding each holder means and axially 
reciprocable relative thereto, the location means having a leading end 
face of greater internal diameter than a bead to be positioned on said 
holder means, which face is provided with means to hold the bead in 
abutment therewith and lies in a plane to which the axis of the former is 
perpendicular, the arrangement being such that a bead may be located on 
each holder means when retracted from the former, the holder means may be 
moved into contact with the associated end of the former and thereafter 
the associated location means may be moved to displace the bead from the 
holder means to a predetermined position along the length of the former 
while the bead is held in abutment with the leading end face of the 
location means. 
Each said holder means may be slidably engaged with the associated location 
means for guided movement axially of the former and spring means may be 
provided to bias the holder means to a normal position extending beyond 
the associated location means toward the associated end of the former, the 
arrangement being such that on movement of each said location means toward 
the former the associated holder means will be retracted against the 
action of the spring means into the location means following abutment of 
the holder means with the associated former end, permitting the 
displacement by the location means of a bead on the holder means from the 
latter onto the former. 
Each said holder means may comprise a plurality of tongues arranged in 
circumferentially separated relation on a circle concentric with the 
former axis, each tongue having at its leading end nearer the former a 
flange directed radially inwardly of said circle to abut the associated 
end of the former, and each said location means may comprise a plurality 
of fingers having at their leading ends nearer the former respective 
abutment members extending circumferentially of a common circle concentric 
with the former axis in circumferentially spaced relation, said abutment 
members of each location means having leading end faces which lie in a 
common plane to which the axis of the former is perpendicular. 
Said means to hold the bead in abutment with the leading end face of each 
location means may be constituted by magnetic means, and each said 
abutment member may comprise at least one permanent magnet bounded by said 
plane. 
In accordance with another aspect of the invention there is provided a 
method of building a pneumatic tire by means of a machine as described in 
the four immediately preceding paragraphs, the method comprising locating 
an inextensible tire bead on and to surround each said holder means while 
the latter is retracted from the associated former end, advancing each 
said holder means into contact with the associated former end, advancing 
each said location means over the associated holder means and former end 
so that the bead on said holder means is first abutted by the leading end 
face of the location means and then held thereagainst in a plane to which 
the axis of the former is perpendicular while being displaced off the 
holder means to a predetermined position along the length of the former, 
expanding the former radially to grip the beads and retracting the 
location means away from the beads and former. 
In the method of the immediately preceding paragraph each bead is 
preferably held magnetically in abutment with the leading end face of the 
associated location means during displacement of the associated holder 
means onto the former. 
One embodiment of the invention will now be described with reference to the 
accompanying diagrammatic drawings, in which: 
FIG. 1 is a perspective view of a tire building machine in accordance with 
the invention, 
FIG. 2 is a perspective view showing in detail a single bead setting device 
of the machine shown in FIG. 1, and 
FIGS. 3, 4 and 5 are side views of a modified bead setting device showing 
different stages of its operation.

The tire building machine shown in FIG. 1 is provided with two bead setting 
device 1,2 mounted one at each end of a flat tire building former 3. Each 
device 1 and 2 comprises support means 4 mounted on shaft 5. Means (not 
shown) are provided to move each support means 4 axially of the former 3. 
On each support means 4 are six elongated fingers 6 in the form of rods of 
circular cross-section mounted parallel to the axis of the former and 
equidistant from it so as to be circumferentially separated around a 
common circle concentric with the former axis. On the leading end nearer 
the former of each finger 6 is provided a transversely extending abutment 
member 10 and on each member 10 are mounted magnets 11, 12 arranged so 
that their pole faces are bounded by a plane to which the axis of the 
former is perpendicular, these pole faces jointly constituting the leading 
end face of bead location means comprising the fingers 6 and abutment 
members 10. 
A block 13 is slidably mounted on the rod 6 and prevented from rotation by 
means of a key (not visible in FIG. 2) co-operating with a keyway 14 in 
shaft 6. Rigidly attached to the block is a longitudinally extending 
tongue 15 the free end of which has a radially inwardly turned flange 16. 
A spring 17 is provided between the block 13 and plate 10. This is a 
Tensator spring unit ("Tensator" is a Registered Trade Mark) which 
comprises a spring strip 18 one end of which is attached to the abutment 
member 10 and the other wrapped round a reel 19 freely rotatably mounted 
on the block 13. The spring is naturally curved and requires a tensile 
force to straighten it as it is pulled from the reel 19. 
The plurality of tongues 15 circumferentially separated round a circle 
concentric with the former axis thus jointly constitute a bead holding 
means surrounded by each bead location means and axially reciprocable 
relative thereto, the springs 18 biassing the tongues 15 to an extended 
position relative to the abutment members 10. 
In operation, with the location and holder means at each end of the former 
retracted away from it a tire bead 20 is loosely located by the operator 
to surround each series of tongues 15. The device at each end of the 
former is then moved towards the former 3 until the flange 16 of each 
tongue 15 comes into contact with the associated end of the former. 
Further inward movement of each device causes the bead on the holder 
tongues 15 to be abutted by the members 10 and held by the magnets 11,12 
and thereafter carried onto the former, while the block/tongue holder 
assembly 13, 15 remains stationary and is held against the former by the 
springs 18 until the required position is reached. The device 2 in FIG. 1 
is shown in this position. The former 3 is thereafter expanded to engage 
and grip the inextensible beads 20, after which the abutment members 10 
can be retracted away from the former back to their starting positions. 
The abutment members 10 are not engaged by the former as the inner 
diameter of the interrupted-annular leading end of each bead location 
means constituted by the abutment members 10 is greater than the inner 
diameter of each bead 20. 
In the modification illustrated in FIGS. 3 to 5 the magnets (not shown) are 
located in housings such as 30 on the leading ends of the fingers 6 and 
the tongues 15 are extensions of sleeves 31 surrounding the fingers. Each 
finger 6 is formed with a longitudinal slot 32 in which a key 33 spanning 
the sleeve 31 thereon is slidable and a Tensator spring 17' is slung under 
the sleeve 31, one end of the spring strip 18' being anchored to the 
housing 30. With the device 1' of FIGS. 1 to 3 retracted from the 
associated end of the former 3 (FIG. 3) a bead assembly 20 is located on 
the tongues 15', after which the device 1' is advanced toward the former, 
causing retraction of the tongues 15' relative to the fingers 6' against 
the action of the spring 18' after the tongues 15' contact the former end 
(FIG. 4) so that the bead assembly 20 is picked up by the magnets and held 
in abutment with the leading end face of each finger. Continued movement 
of the fingers 6' in the same direction causes the bead assembly 20 to be 
carried to a final position intermediate the ends of the former 3 (FIG. 
5). 
It will be evident that if desired the fingers 6 and abutment members 10 
could be replaced by a single, annular bead location means and that the 
tongues 15 could be replaced by a single annular bead holding means. It 
will also be evident that interconnection of the relatively movable bead 
location and bead holding means is not essential.