Field of the Invention
This invention relates generally to cord configurations
in a tire ply and, more specifically, to a tire having at least one ply formed by
split end cords applied in a preferably geodesic cord configuration.
Background of the Invention
Historically, the pneumatic tire has been fabricated as
a laminate structure of generally toroidal shape having beads, a tread, belt reinforcement,
and a carcass. The manufacturing technologies employed for the most part involved
assembling the many tire components from flat strips or sheets of material. Each
component is placed on a building drum and cut to length such that the ends of the
component meet or overlap creating a splice.
In the first stage of assembly the prior art carcass will
normally include one or more plies, and a pair of sidewalls, a pair of apexes, an
innerliner (for a tubeless tire), a pair of chafers and perhaps a pair of gum shoulder
strips. Annular bead cores can be added during this first stage of tire building
and the plies can be turned around the bead cores to form the ply turnups.
This intermediate article of manufacture would be cylindrically
formed at this point in the first stage of assembly. The cylindrical carcass is
then expanded into a toroidal shape after completion of the first stage of tire
building. Reinforcing belts and the tread are added to this intermediate article
during a second stage of tire manufacture, which can occur using the same building
drum or work station.
This form of manufacturing a tire from flat components
that are then formed toroidially limits the ability of the tire to be produced in
a most uniform fashion. As a result, an improved method and apparatus has been proposed,
the method involving applying an elastomeric layer on a toroidal surface and placing
and stitching one or more cords in continuous lengths onto the elastomeric layer
in predetermined cord paths. The method further includes dispensing the one or more
cords from spools and guiding the cord in a predetermined path as the cord is being
The above method is performed using an apparatus for forming
an annular toroidially shaped cord reinforced ply which has a toroidal mandrel,
a cord dispenser, a device to guide the dispensed cords along predetermined paths,
a device to place an elastomeric layer on the toroidal mandrel, a device to stitch
the cords onto the elastomeric layer, and a device to hold the cords while loop
ends are formed. The device to stitch the cords onto the elastomeric layer includes
a bi-directional tooling head mounted to a tooling arm. A pair of roller members
is mounted side by side at a remote end of the tooling head and defining a cord
exiting opening therebetween. The arm moves the head across the curvature of a tire
carcass built on a drum or core while the cord is fed through the exit opening between
the rollers. The rollers stitch the cord against the annular surface as the cord
is laid back and forth across the surface, the first roller engaging the cord along
a first directional path and the second roller engaging the cord in a reversed opposite
second directional path.
The toroidal mandrel is preferably rotatable about its
axis and a means for rotating is provided which permits the mandrel to index circumferentially
as the cord is placed in a predetermined cord path. The guide device preferably
includes a multi axis robotic computer controlled system and a ply mechanism to
permit the cord path to follow the contour of the mandrel including the concave
and convex profiles.
While working well, the industry remains in need of additional
tire constructions that can benefit from the use of advanced manufacturing techniques
such as summarized above. Tire configurations that take advantage of the speed,
efficiency, and cost improvement potential in applying a cord by means of single
cord line application to a toroidal building drum are needed. Specifically, tire
configurations, component construction, and methods of manufacture thereof that
improve tire uniformity and performance, at a reduced cost, are in demand.
Summary of the Invention
The invention relates to a cord ply construction according
to claim 1, a tire having a specific cord ply construction according to claim 9
and a method according to claim 10. Dependent claims cover embodiments of the invention.
Pursuant to a preferred aspect of the invention a cord
ply construction for a tire is provided formed by a series of spaced single line
cord paths, each extending along a path from an originating side of the tire across
the crown region to an opposite terminal tire side, the cord paths each creating
a loop at the terminal tire side and returning to the originating side and wherein
the series of spaced single line cord paths combine to form a completed cord ply
layer. Each cord path forms a cord angle that changes in magnitude from the originating
side to the terminal tire side, the cord angle being greatest at the originating
tire side and decreasing as the cord crosses a tire tread centerline.
According to another preferred aspect of the invention,
oppositely directed first and a second ply layers, each formed according to the
configuration summarized above, are disposed to overlap at the tire crown region.
Pursuant to a further aspect of the invention, a tire is formed having multiple
cord layers, the cords in each cord layer following a path from an originating tire
side to a terminal tire side and each path forming an angle relative to the tire
centerline that varies along the cord path.
"Axial" and "axially" means the lines or directions that
are parallel to the axis of rotation of the tire.
"Circumferential" means lines or directions extending along
the perimeter of the surface of the annular tread perpendicular to the axial direction.
"Carcass" means the tire structure apart from the belt
structure, tread, undertread, over the plies, but including beads, if used, on any
alternative rim attachment.
"Casing" means the carcass, belt structure, beads, sidewalls
and all other components of the tire excepting the tread and undertread.
"Cord" means one of the reinforcement strands the plies
for instance in a tire comprise.
"Equatorial Plane (EP)" means the plane perpendicular to
the tire's axis of rotation and passing through the center of its tread.
"Placement" means positioning a cord on a surface by means
of applying pressure to adhere the cord at the location of placement along the desired
"Ply" means a layer of rubber-coated parallel cords.
"Radial" and "radially" mean directions radially toward
or away from the axis of rotation of the tire.
"Winding" means a wrapping of a cord under tension onto
a convex surface along a linear path.
Brief Description of the Drawings
The invention will be described by way of example and with
reference to the accompanying drawings in which:
Detailed Description of the Illustrative Embodiments
- FIG. 1 is a perspective view of a tire making station employing a plurality
of ply laying assemblies, each configured pursuant to an aspect of the invention.
- FIG. 1A is a perspective view similar to FIG. 1 showing the tire making station
enclosed within a protective cage.
- FIG. 2 is a side elevation view of the tire making station showing spatial dispensation
of plural ply laying assemblies about a tire build core.
- FIG. 3A is an enlarged perspective view of one ply laying assembly disposed
at an initial position relative to a tire build core that is partially sectioned
- FIG. 3B is an enlarged perspective view of the ply making assembly shown in
FIG. 3A at a subsequent intermediate position along a ply laying path relative to
the tire build core.
- FIG. 3C is an enlarged perspective view of the ply laying assembly shown in
FIG. 3A at a subsequent terminal position relative to the tire build core.
- FIG. 4 is a front elevation view shown in partial transverse section for illustration
of a ply laying apparatus configured pursuant to the invention at the terminal position
relative to the tire build core.
- FIG. 5 is an enlarged perspective view of ply laying assembly.
- FIG. 6 is a rear elevation view of the ply laying assembly.
- FIG. 7 is a side elevation view of the ply laying assembly showing sequential
operation of the support arm slide mechanism in phantom.
- FIG. 8 is a transverse section view through the ply laying apparatus.
- FIG. 9 is a side elevation view of the ply laying apparatus co-mounted adjacent
a cord tensioning and feed assembly.
- FIG. 10 is an enlarged perspective view of the cord tensioning and feed assembly.
- FIG. 11 is a bottom plan view of the ply laying assembly.
- FIG. 12 is a transverse section view through the ply laying end of arm tooling.
- FIG. 13A is a transverse section view through the ply laying end of arm tooling
shown in the retracted position and shown in phantom in the axially elongated position.
- FIG. 13B is a transverse section view through the ply laying end of arm tooling
of FIG. 13A shown in the axially elongated position.
- FIG. 14 is a transverse section view through the ply laying end of arm tooling
of FIG. 13A shown moving in a tilted forward direction.
- FIG. 15 is a transverse section view through the ply laying end of arm tooling
of FIG. 13A shown moving in a reverse tilted reverse direction.
- FIG. 16 is a front right perspective view of the ply laying end of arm tooling
with portions sectioned for clarity.
- FIG. 16A is a partially exploded perspective view of the roller assembly of
the ply laying end of arm tooling.
- FIG. 16B is a left side perspective view of the end of arm tooling without the
outer housing shown for the purpose of illustrating the position of the shear piston
and linkage in the position.
- FIG. 16C is a left side perspective view of the end of arm tooling without the
outer housing shown for the purpose of illustrating the position of the shear piston
and linkage in the retracted position.
- FIG. 17 is an exploded perspective view of the cord cutting subassembly of the
ply laying end of arm tooling.
- FIGS. 18A-D are sequential views of the tire forming mandrel showing the build
of a ply layer by means of single cord application pursuant to the invention.
- FIGS. 19-28 are representative ply cord patterns that may be applied to an annular
core surface pursuant to the invention.
Referring initially to FIGS. 1, 1A, and 2, a machine assembly
10 is shown for the construction of a tire on a core assembly 11. The core assembly
11 is generally of toroidal shape and a tire is formed thereon by the sequential
layering of tire components on the toroidal form of the core. A platform 12 may
be deployed as support for the assembly 10. A drive motor 14 is coupled by a conventional
shaft to rotate the core assembly 11 as tire component layers are sequentially applied
to the toroidal core.
The referenced drawings depict four arm assemblies 16 A-D
surrounding the core assembly in a preferred arrangement. While four assemblies
are incorporated in the system embodiment 10, the invention is not to be so limited.
A single arm assembly may be used if desired. Alternatively, more or fewer than
four assemblies may constitute the system if desired. The four arm assemblies 16
A-D are disposed to surround the core assembly 10 at a preferred spacing that allows
the arm assemblies to simultaneously construct a cord ply to respective regions
of the toroidal core. Dividing the surface area of the toroidal core into four quadrants,
each assigned to a respective one of the four arm assemblies, allows the cord ply
layer to be formed simultaneously to all four quadrants, whereby expediting the
process and saving time and manufacturing cost.
A core removal assembly 18 is shown disposed to remove
the core assembly 11 from between the arm assemblies 16 A-D once tire construction
on the core is complete. An appropriate computer control system conventional to
the industry may be employed to control the operation of the system 10 including
arm assemblies 16 A-D. A control system of the type shown will typically include
a housing 22 enclosing the computer and system control hardware. Electrical control
signals will be transmitted to the system 10 by means one or more suitable cable
conduit such as that show at numeral 23.
A cage or peripheral guard structure 24 may enclose the
system 10 as shown in FIG. 1A. An additional pendant control unit 26 for the control
cooler unit 20 is mounted to the guard 24. Each of the arm assemblies 16A-D is serviced
by a cord let off assembly or spool 28, only one of the four being shown in FIG.
2 for the sake of clarity. A balancer assembly 30 is associated with each let off
assembly 28 for placing cord 32 fed from the assembly 28 in proper tension and balance.
The cord 32 is fed as shown through the balancer assembly 20 to the arm assembly
In FIGS. 3A-C and 4, operation of one arm assembly 16D
is sequentially depicted and will be readily understood. The arm assembly 16D is
configured to provide end of arm tooling assembly 34 carried by C-frame arm 36,
electrically serviced by suitable cabling extending through cable tray 38. As explained
previously, the core assembly 11 is configured having a rotational axial shaft 40
and a segmented toroidal core body 42 providing an annular outer toroidal surface
43. A main mounting bracket 44 supports the end of arm tooling assembly 34 as well
as a drive motor 46 and clutch assembly 48. As best seen from joint consideration
of FIGS. 4, 5, 6, 7, and 8, the C-frame arm 36 is slideably attached to a Z-axis
vertical slide member 50 and moves along a Z-axis to traverse the width of the outer
core toroidal surface 43. Movement of the arm 36 along slide member 50 facilitates
the laying of cord on cores for tires of varying sizes. FIG. 3A depicts the arm
assembly 36 at a beginning position relative to surface 43; FIG. 3B a position mid-way
along the transverse path across surface 43; and FIG. 3C a terminal transverse position
of assembly 36 at an opposite side of the surface 43. FIG. 7 illustrates the movement
of arm assembly 36 along slide 50 to facilitate movement of assembly 36 between
the sequential positions illustrated in FIGS. 3A-C. Drive shaft 51 is coupled to
the arm assembly 36 as seen from FIG. 8 and drives the assembly along the Z-axis
path in reciprocal fashion responsive to control instructions.
An end of arm tooling motor 52 is further mounted on arm
assembly 36 and rotatably drives end of arm tooling shaft 54. The end of arm tooling
34 consists of a bi-directional cord laying head assembly 56, an intermediate housing
assembly 57, and an upper housing assembly 59. The end of arm tooling 34 further
includes a cord tensioning sub-assembly 58 as shown in detail in FIGS. 9 and 10.
Sub-assembly 58 includes a drive motor 60, the motor 60 being mounted on an S-shaped
block 62. The sub-assembly 58 further includes a first pulley 64; a spatially adjustable
cord pulley 65; and a third pulley 66. An elongate closed-end tensioning belt 68
routes around the pulleys 64, 66 as shown. A cord guiding terminal tube 70 extends
from the pulley and belt tensioning region of assembly 58 through the block 62.
An initial cord guiding passageway 72 enters into the block 62 and guides cord 32
through the block and into the tensioning region of assembly 58. Belt 68 is routed
around pulleys 64, 66 and is rotated thereby. It will be appreciated that the cord
32 is routed as shown between belt 68 and pulley 65 and is axially fed by the rotation
of belt 68 through the assembly 58. By adjusting the relative position of pulley
65 against the cord 32 and belt 68, the cord 32 may be placed in an optimal state
of tension for subsequent routing through an applicator head. The tensioning of
the cord 32 is thus optimized, resulting in a positive feed through the block 62
and to an applicator head as described following. Breakage of the cord that might
otherwise occur from a more or less than optimal tension level is thus avoided.
Moreover, slippage of the cord caused by a lower than desired tension in the cord
is likewise avoided. Additionally, the subject cord tensioning sub-assembly 58 acts
to eliminate pinching of the cord that may be present in systems employing rollers
to advance a cord line. Pinching of the cord from a roller feed may act to introduce
a progressive twist into the cord that will release when the cord is applied to
a surface, and cause the cord to move from its intended location. The assembly 58,
by employing a belt cord advance, eliminates twisting of the cord and ensures that
the cord will advance smoothly without impedance.
Referring next to FIGS. 11, 12, 13A, 13B, and 17, the bi-directional
cord laying head assembly 56 will be described. In general, the applicator head
56 is located at a terminal end of the end of arm tooling assembly 34. The head
assembly, as described below, functions to apply cord to the annular toroidal core
surface 43 in a preselected pattern as one layer in the plurality of layers built
upon the core 42 during construction of a tire. A pair of applicator guide rollers
74, 76 are rotatably mounted in-line to a terminal end of the end of arm tooling
34, the rollers defining a cord outlet 78 therebetween with the pivot shafts of
the rollers being preferably, but not necessarily, substantially co-axial. More
or fewer rollers may be employed if desired pursuant to the practice of the subject
invention. The bi-directional cord laying head 56 is constructed to provide a final
cord guide tube 80 extending axially to a remote end in communication with the cord
outlet opening 78 between the rollers.
The intermediate assembly 57 includes a pre-loaded coil
spring 82 that seats within a spring housing 84 residing within an outer housing
block 85. The bi-directional cord laying head assembly 56 is placed in a downward
bias against the surface 43 by the pre-loaded coil spring 82. O-rings 86 A-F are
suitably located between adjacent housing block elements. The intermediate assembly
57 further includes a lower housing 88 receiving a housing block 89 therein. A terminal
end of the block 89 is closed by an end cap 90 with the intersection sealed by means
of O-rings 91. The block 89 represents a plunger, or piston, slideably contained
within the outer housing 88 that moves axially relative to the end of arm tooling
for a purpose explained below. The end of arm tooling 34 is pivotally mounted to
the bracket 62 and reciprocally rotated by means of drive shaft 54 in the direction
69 as will be appreciated from FIG. 9.
FIGS. 11, 12, 13A, and 13B depict in section the end of
arm tooling 34 including assemblies 56, 57, and 59. As shown, plural intake portals
92, 94, and 96 extend into the tooling assembly at respective axial locations; cylinder
92 representing a pressurized air inlet for assisting in the feeding of a severed
cord end down the axial passageway of the end-of-arm assembly; cylinder 94 providing
air pressure and forming an air spring by which the head assembly of the end of
arm tooling is maintained at a constant pressure against the annular surface of
the core; and cylinder 96 providing a pressurized air inlet that, upon actuation,
initiates a shearing of the cord. The rollers 74, 76 mount to a nose block 97 that
is slideably connected at a lower end of housing 89 by assembly pin 67. Pin 67 is
keyed within a vertical slot in the housing 89 and prevents the nose block 67 from
rotating. The block 67 and the rollers 74, 76 are thus maintained in an aligned
orientation to the surface 43 of the core.
From FIG. 9, it will be appreciated that the end-of-arm
tooling assembly 34 is pivotally mounted to the bracket 62 and is fixedly coupled
to motor shaft 54. Shaft 54 is driven rotationally by a computer controlled servo-motor
(not shown) in conventional fashion. A rotation of the shaft 54 translates into
pivotal movement of assembly 34. As the assembly 34 pivots, the rollers 74, 76 tilt
or pivot backward and forward, alternatively bringing the rollers into contact with
the core surface 43.
It will further be appreciated from FIGS. 13A and 13B,
and FIGS. 16B-D, that the piston, or plunger, 89 moves axially within the assembly
housing 88 in reciprocal fashion. Piston 89 moves independently of the bi-directional
head 56. Thus, head 56 can remain in continuous contact with the core surface 43
at a constant, optimal pressure maintained by pressure intake 94. As head 56 and
surface 43 remain in contacting engagement, the piston 89 is free to move axially
within housing 88 under the influence of spring 82 between the extended position
shown in FIG. 13B and FIG. 16C, and the axially retracted position shown in FIG.
13A and FIG. 16D. Spring 82 is in a compressed, pre-loaded condition with the piston
89 in the retracted axial position of FIGS. 13A and 16D, under load from pressure
at intake 96. Upon removal or reduction of air pressure at intake 96, plunger block
89 moves to the extended position shown in FIGS. 13B and 16C, and spring 82 extends.
A resumption of controlled air pressure at intake 96, under computer control, pressures
piston 89 into the retracted position and reloads spring 82. Linear movement of
the plunger block 89 is along the center axis of the end of arm tooling 34.
The final guide tube 80 extends along the center axis of
the end-of-arm tooling 34 and, as will be understood from FIGS. 13A and 13B, the
cord 32 is routed along the center axis of the upper assembly 59, the intermediate
assembly 57, and the bi-directional cord laying head assembly 56 of the tooling
34 to exit from the cord outlet opening 78 between rollers 74, 76 (FIGS. 11, 12).
The cord 32 thereby is positioned and pressured by the rollers 74, 76 against the
core surface 43 in a preferred pattern. Depending upon the pattern of the cord layer
to be applied to surface 43, the process of applying the court will require that
the cord be cut one or more times. A preferred cutting mechanism will be described
With reference to FIGS. 15B, 16, 16B, and 17, the upper
assembly 59 includes a cable shear assembly 98, activated by a pair of lever arms
102,104 that extend axially along opposite sides of the piston 89 within housing
88. The upper assembly 59 includes a mounting base flange 100 that mounts to a bearing
plate 101 (FIG. 9) by means of screws 108, 110. The bearing plate 101 is rotatably
mounted to the end bracket 62. As described previously, the end of arm tooling 34
may thus be rotated by motor driven shaft 54. It will be appreciated from FIG. 17
that the spring 82 seats within spring housing 84 enclosed by spring end cap 112.
A forward end of spring 82 seats within the end cap 112. End cap 112 includes a
circular protrusion 114 and a through bore 16. End cap 112 is contained within the
piston 89 as shown. O-ring 118 and washer 120 are interposed against the forward
end of the spring 82 within the cap 112.
The housing block 85 includes an axial passageway 128.
A recessed peripheral ledge 122 circumscribes a forward end of the passageway 128
and a through bore 124 extends into and through the housing ledge 122. A slide pin
126 projects through the bore 124 of housing 85, the bore 116 of cap 112, and into
the housing 89 as shown. Piston 89 is thus slideably coupled to the block 85 and
moves reciprocally in an axial direction relative thereto as described above.
A transverse bore 130 extends through housing 85 from side
to side in communication with passageway 128. Mounting flanges 132, 134 extend laterally
from the housing 85 and mounting screws 134 project through the flanges and into
housing 88 to secure housing 85 to housing 88. The cord cutting assembly 98 includes
a tubular member 136 rotatably residing within the transverse bore 130 and projecting
from opposite sides of the housing 85. An attachment lug 138 projects outward from
an end of the tubular member 136 and carries an inward facing attachment stud 139.
The tubular member 136 has locking flanges 140 at an opposite end and a centrally
disposed axial through bore 142. A transverse bore 144 having a funnel shaped guide
entry 145 is positioned to extend through the tubular member 136.
A connector block 146 is attached to an end of the tubular
member 136 and includes a locking socket 148 engaging the locking flanges 140 of
member 136. An attachment stud 150 extends inwardly from the block 146. Piston 89
is configured having a cylindrical rearwardly disposed socket 152 stepping inward
to a forward smaller diametered cylindrical portion 154. Outwardly projecting pin
members 156 extending from opposite sides of the cylindrical portion 154 of the
piston 89. As will be appreciated, forward ends 158 of pivot arms 102, 104 fixedly
attach to the pins 156 and rearward ends of the arm 102, 104 fixedly attach through
the studs 150, 139, respectively, to flanges 146, 138 of the tubular component 136.
Tubular member 136 resides within the transverse bore 130
of the block 85 and rotates freely therein. The ends of member 136 are journalled
to the piston 89 through lever arms 102, 104. The funnel shaped entry 145 is positioned
facing axially rearward of assembly 34. The cord 32 is dispensed and routed downward
through entry 145 of member 136 and exits from the transverse bore 144 along the
longitudinal center axis of the end of arm tooling assembly 34. As described previously,
spring 82 is in a pre-loaded, state of compression between housing 85 and piston
89 while the cord 32 is applied in a predesigned pattern to the annular outer core
surface 43. At the completion of the cord laying sequence or at required interim
points in the application process, the cord 32 may be severed through the operation
of shear assembly 98. An axial movement of the piston is initiated by a reduction
of air pressure at intake 94. Spring 82 thereupon is uncoils and influences the
piston 89 axially away from the housing 85. As the piston 89 moves away from the
housing 85, the lever arms 102, 104 pull against the ends of the tubular member
136 and impart rotation thereto within housing block 85. As the member 136 rotates,
edges defining the funnel shaped entry 145 are rotated into severing engagement
against the cord 32 extending through the member 136. The cord 32 is thereby severed.
The free end of cord 32, subsequent to the severing procedure, is generally in an
axial alignment with the tooling assembly 34.
To re-route the cord 32 down the assembly 34 in order to
resume laying cord, air pressure is re-applied through intake 94 and piston 97 is
forced into the higher, retracted position of FIG. 13A, whereupon recompressing
spring 82. Movement of the piston 89 into the retracted position causes the lever
arms 102, 104 to rotatably return the tubular member 136 into its normal orientation
within block 85. So oriented, the shearing edges defining funnel entry 145 of member
136 are in a non-contacting relationship to cord 32 and funnel entry 145 and transverse
bore 144 are axially aligned with the center axis of tooling assembly 34. The severed
end of cord 32 is thereafter re-routed down the axis of tooling assembly 34 to exit
from the gap 78 between rollers 72, 74. To assist in the re-routing of the free
end of cord 32, pressurized air is introduced through intake 92 and the forced air
pushes the free end of the cord 32 along its axial path. The time required to re-position
the end of the cord 32 at the outlet 78 is thereby reduced and cycle time minimized.
The free severed end of cord 32 upon exiting between rollers 74, 76 is thus positioned
for application to the core surface as a smooth linear feed of the cord 32 through
the end of arm tooling is resumed.
Rollers 74, 76 are shown in FIG. 16 A as rotationally mounted
to respective axial center shafts 166, 168. Shafts 166, 168 mount between a flange
extension 170 of the nose block 97 and a retainer 172. So disposed, the rollers
74, 76 are axially parallel and spaced apart a distance sufficient to allow the
cord 32 to pass therebetween. The retainer 172 includes adjacent sockets 174, 176
that receive upper ends of the shafts 166, 168 therein. An assembly aperture 178
projects through a rearward surface 182 of retainer 172 as shown. Each of the rollers
74, 76 is configured to provide a circumferential channel 180 having a sectional
profile and dimension complimentary with the sectional configuration of cord 32.
The nose block 97 receives the cord guide tube 80 therethrough with a forward end
of tube 80 disposed adjacent the gap 78 between rollers 74, 76.
Assembly of the end of arm tooling 34 will be readily apparent
from FIGS. 13 A,B; 16, and 17. The nose block 97 is fixedly coupled to the housing
88 by the pin 67. The motor shaft 54 rotates reciprocally and causes the end of
arm tooling to resultantly reciprocally rotate through an angular travel of plus
or minus three to eight degrees. A greater or lesser range of pivotal movement may
be used if desired. Pivotal movement of commensurate angular travel of in-line rollers
72, 74 is thus effected as best seen from FIG. 9. Each roller 72, 74 is alternatively
brought into and out of engagement against the core surface 43 through the pivotal
movement of assembly 34. The pressure applied by each roller 72, 74 against the
surface 43 is controlled through application of appropriate air pressure through
the intake portal 94.
As seen from FIGS. 3A-C; 5; and 7, end of arm tooling 34
mounts to the C- frame arm 36 and is carried thereby toward and away from the surface
43 of core 42. The C-frame arm 36 is slideably mounted to the Z-axis slide 50 and
reciprocally moves end of arm tooling 34 laterally across the surface 43 in a predefined
pattern. Adjustment in the Z axis along slide 50 is computer controlled to coordinate
with the other axis of adjustment of end of arm tooling 34 to allow for the application
of cord to cores of varying sizes. The cord 32 is dispensed from cord let-off spool
28, through a conventional balancer mechanism 34 and to the arm assembly. The end
of cord 32 is routed at the end of arm cord tensioning assembly 58 (FIGS. 9 and
10) and then into the axial passageway through end of arm tooling assembly 34. Upon
entering assembly 34, the cord 32 passes through the tubular member 136 of the cable
shear assembly 98 and then proceeds along the axial guide passage 80 to the cord
outlet 78 between rollers 74, 76. The cord is received within a circumferentially
located roller channel 180 in each roller 74, 76, the roller receiving the cord
being dependent upon the intended direction of travel of the cord across surface
43 pursuant to the predefined pattern. Appropriate pressure of the cord 32 by either
roller 74 or 76 against a pre-applied carcass layer on core 42 causes the cord to
adhere to the carcass layer at its intended location, thus forming the designed
cord layer pattern.
Referring to FIGS. 12, 13B, 14, and 15, the alternative
tilting operation of the end of arm tooling in regard to rollers 74, 76 will be
explained. The rollers 74, 76 tilt along an angular path represented by angle q
(FIGS. 14 and 15) relative to the centerline of the end of arm tooling. Alternatively
one or the other roller is in a dependent position relative to the other roller
as a result of the pivotal movement of assembly 34. In a forward traverse of the
tooling assembly across a carcass layer mounted to the core surface 43, one of the
rollers will engage the cord 32 within roller channel 180 and stitch the cord 32
against the layer. For a reverse traverse of the tooling head across the carcass
layer, the assembly 34 is tilted in a reverse direction to disengage the first roller
from the cord 32 and place the second roller into an engaging relationship with
cord 32. The second roller then effects a stitching of the cord 32 against the carcass
layer mounted to core 42 in a reverse traverse.
The reciprocal pivotal movement of the end of arm tooling
34 is carefully coordinated with rotational indexing of the core 42 and lateral
movement of the tooling assembly 34. Referring to FIGS. 5 and 6, it will be appreciated
that the subject assembly 34 in combination with the core drive constitutes a system
having three axis of rotation. A first axis is represented by a pivoting of assembly
34 through an angular tile by the drive shaft 54. Shaft 54 is preferably driven
by a computer controlled servo-motor 52. A second axis of rotation is the lateral
rotation of the assembly 34 driven by motor 46. Motor 46 is preferably, but not
necessarily a computer controlled ring motor that, responsive to computer generated
control signals, can accurately index the assembly 34 along a rotational path following
the outer surface 43 of the core 42. A third axis of rotation is the indexing of
the core spindle 42 by motor 14 (FIG. 1). Motor 14 is preferably, but not necessarily
a ring motor that, responsive to computer generated control signals, can accurately
index the core 42 in coordination with the ring motor 46 rotationally driving the
The arm assembly 16 A, carrying end of arm tooling 34,
is further adjustable along a linear path representing a z-axis as shown in FIGS.
5,6, and 7. The arm assembly 16A travels along the slide 50 controlled by a timing
belt drive 49. Movement of the assembly 16 A along slide 50 is computer controlled
to correlate with the size of the core on which the cord is applied. One or more
computers (not shown) are employed to coordinate rotation of core 42 (by ring motor
14); rotation of end of arm tooling assembly 34 (by ring motor 46); linear path
adjustment of assembly 16A along the Z-axis (by timing belt drive of assembly 16A
along slide 49); and tilting adjustment of assembly 34 (by servo-motor 52). The
assembly thus precisely controls the movement of assembly 16A in three axis of rotation
and along a linear path (slide 50) to enable tooling assembly 34 to accurately place
cord 32 in an intended pattern on a surface 43 of a core 42 of varying size without
need for specialized equipment to form a loop in the cord at the end of each traverse.
Creation of the loop at the conclusion of each traverse is accomplished by an indexed
controlled rotation of the core 42. Thus, the cord laying assembly functions to
form the loop without the need for a finger mechanism to engage, press, and release
the cord. The pattern of cord applied to the carcass layer upon core 42 may thus
be tailored to provide optimum performance while conserving cord material, resulting
in reduced cost of manufacture.
As will be appreciated, a reciprocal pivoting movement
of the end of arm tooling head that alternately places one of the rollers 74, 76
into engagement with cord 32 while disengaging the opposite roller results in several
significant advantages. First, in disengaging one of the rollers from the carcass
layer, the frictional drag of the disengaged roller is eliminated. As a result,
the associated drive motor that drives the end of arm tooling may operate with greater
speed and efficiency. Additionally, redundant and unnecessary engagement of the
disengaged roller from the cord 32 with the underlying elastomeric layer and the
cord is eliminated, reducing the potential for damage to both the cord 32 and the
underlying carcass layer. Moreover, in utilizing dual rollers mounted in-line, the
speed of cord application is at which the cord 32 is applied to the carcass may
be improved and the drive mechanism simplified.
It will be appreciated that the application head portion
of the tooling 34 is air spring biased against the surface 43 of core 42 during
the application of cord 32 through pressurized intake 94. The air spring created
by intake 94 exerts a substantially constant force through nose housing 97 to rollers
74, 76. The biasing force upon rollers 74, 76 is applied to cord 32 as described
above, and serves to pressure the cord 32 against a carcass layer previously applied
to the core surface 43. The tackiness of the pre-applied layer retains the cord
32 at its intended placement. A more secure placement of the cord 32 results, and
the potential for any unwanted, inadvertent post-application movement of the cord
32 from the underlying carcass layer is minimized. At the appropriate time for severing
the cord 32 by means of the shearing assembly 98, separation of housings 89 and
85 is effected as shown in FIG. 15B, 16, 16B-D as described previously.
As described previously, to reposition the severed end
of the cord 32 for another application cycle, pressurized air is introduced through
intake portal 92 and pneumatically forces the free cord end down the axial passageway
80 to the cord outlet 78 between rollers 74, 76. Application of the cord to the
carcass layer on the core 42 may then recommence.
With reference to FIGS. 1, 1A, and 2, it will further be
appreciated that a plurality of like-configured arm assemblies 16 A-D may, if desired
at the option of the user, be deployed at respective circumferential locations about
the core 42 in operable proximity to the core surface 43. Each of the plurality
of arm assemblies is assigned a specific region of the annular core surface 43.
The plural arm assemblies may then simultaneously apply a cord layer pursuant to
the above recitation to its respective assigned region. In segmenting the cord annular
surface 43 between multiple arm assemblies and simultaneously applying the cord
by means of the arm assemblies, a faster cycle time results. While four arm assemblies
16 A-D are shown, more or fewer arm assemblies may be deployed if desired.
Referring to FIGS. 18A-D, 19-27. to advance the cords 32
on a specified path 190, the end of arm tooling mechanism 34 which contains the
two rollers 74, 76 forms the cord outlet 78 which enables the cord path 190 to be
maintained in this center. As illustrated, the cords 32 are held in place by a combination
of embedding the cord into an elastomeric compound 192 previously placed onto the
toroidal surface 43 and the surface tackiness of the uncured compound. Once the
cords 32 are properly applied around the entire circumference of the toroidal surface
43 a subsequent lamination of elastomeric topcoat compound (not shown) can be used
to complete the construction of the ply 194. It will be appreciated that more than
one cord layer may be applied to the core 42, if desired or required. Additional
elastomeric layers may be added to the core and additional cord layers applied as
described above. Optionally, if desired, the top or bottom coat of elastomeric material
may be eliminated and the cord applied in successive layers to form multiple plies
on the core 42.
As illustrated and explained previously, the first roller
76 will embed the cord 32 on a forward traverse across the toroidal surface 43 as
illustrated in Fig. 14. Once the cord path 190 has been transferred across the toroidal
surface 43 the mechanism 34 stops and the cord 32 is advanced along the toroidal
surface 43 by rotation of the core 42. The mechanism 34 then reverses its path 190
forming a loop 196 in the ply cord path 190. At this point a tilting of the end
of arm tooling head block 97 causes the first roller 76 of the pair to disengage
and the second roller 74 to engage the cord 32 to pull the cord 32 back across the
toroidal surface 43.In the preferred embodiment the toroidal surface 43 is indexed
or advanced slightly allowing a circumferential spacing or pitch (P) to occur between
the first ply pathway down in the second return ply path. The loop 196 that is formed
on the reverse traverse is slightly shifted to create the desired loop position.
A looped end 196 may be formed and the second ply path 190 may be laid on the toroidal
surface 43 parallel to the first ply path, or other geometric paths may be created
by selective variation in the core indexing (rotation) coupled with the speed at
which the end of arm tooling head traverses the core surface 43 in the forward and/or
The process is repeated to form a series of cords 32 that
are continuous and which have the intended preselected optimal pattern. For example,
without intent to limit the patterns achievable from the practice of the invention,
the toroidal core 42 with the toroidal surface 43 with an elastomeric compound 192
laminated onto it may be indexed or advanced uniformly about its axis with each
traverse of the pair of rollers 74,76 to create a linearly parallel path 190 uniformly
distributed about the toroidal surface 43. By varying the advance of the cord 32
as the mechanism 34 traverses, it is possible to create non-linear parallel cord
paths 190 to tune tire stiffness and to vary flexure with the load.
Preferably the cord 32 is wrapped around the tensioner
assembly 58 to adjust and maintain the required tension in the cord 32 (FIG. 10).
The pulley 65 is laterally adjustable to alter the tension in the belt 68 which,
in turn engages the cord 32 passing beneath pulleys 64, 66 and over pulley 65. More
or less tension in the belt 68 translates into more or less tension in the cord
32. If the cord 32 is too tight it will lift the cord from the coat laminate when
the rollers 74, 76 reverse direction. If it is too loose it will not create a loop
at the correct length. Moreover, the amount of tension applied has to be sufficiently
small that it does not lift the cords 32 from their placed position on the toroidal
surface 43. The cord 32 under proper tension will rest on the toroidal surface 43
positioned and stitched to an elastomeric layer 192 such that the tack between the
cord 32 and the elastomeric layer 192 is larger than the tension applied by the
tensioner assembly 58. This permits the cords 32 to lay freely onto the toroidal
surface 43 without moving or separating during the ply construction period.
With reference to Figures 18A-D, depicted is a three dimensional
view of a cylinder representing how the ply path 190 is initiated along what would
generally be considered the bead region 198 of the carcass 194 along the tire sidewall
200 toward the shoulder region 202 of the toroidal surface 43 and then traverses
across the toroidal surface 43 in an area commonly referred to as the crown 204
as illustrated in Figure 18B. In Figure 18B it will be noticed that the ply cord
path 190 is laid at a slight angle. While the ply path 190 may be at any angle including
radially at 90° or less, the ply path 190 also can be applied in a non-linear
fashion. As shown in Figure 18C, once the ply cord 32 is traversed completely across
the toroidal surface 43 and down the opposite side the loop 196 is formed as previously
discussed and the cord 32 is brought back across the crown 204 as shown in Figure
18C. In Figure 18D the cord 32 then proceeds down the tire sidewall 200 towards
the bead region 198 where it is turned forming a loop 196 as previously discussed
and then traverses back across the toroidal surface 43 in a linear path 190 as illustrated
that is parallel to the first and second ply cord paths 190. This process is repeated
in Figures 19 and 20 as the toroidal surface 43 is indexed, creating a very uniform
and evenly spaced ply cord path 190.
Other cord patterns may be devised and implemented using
the end of arm tooling 34 of the present invention. The speed at which core 42 is
rotated and or the speed of the traverse travel of the tooling head 56 across surface
43 may be varied in order to generate patterns of preferred configuration. By way
of example, cord laying patterns are depicted in FIGS. 19-27 showing sample cord
pattern configurations. The present invention is not intended to be limited to those
patterns depicted and other patterns obvious to those skilled in the art may be
With reference to FIG. 28, the subject invention in a preferred
cord configuration employs at least one cord ply having a geodesic configuration.
As used herein, a geodesic cord path is defined as the shortest path between two
points on a curved surface. A cord laying in this path will have uniform tension
everywhere in the cord and zero shear between any other adjacent cord or layer.
This path also represents the minimum cord length possible in a tire between any
two points on opposite beads and therefore minimizes tire weight. Its geometry is
directly opposite to the conventional cord path. The cord angle is lowest at the
tread centerline and increases rather rapidly when approaching the bead area.
The absence of shear in the structure produces many desirable
qualities; such as, (1) increased separation resistance, (2) reduced operating temperature,
(3) lower rolling resistance, and (4) improved traction due to more latitude in
tread compounding. The high crown angles provide improved ride characteristics,
and the low angles at the bead improve bead durability. The mathematics underlying
this information are derived from a publication by John F Purdy, "Mathematics Underlying
The Design Of Pneumatic Tires". The subject apparatus and single line cord application
process described previously greatly facilitates the construction of true geodesic
ply path cord tires as a viable and manufacturingly feasible tire.
With specific reference to FIG. 28, multiple cord plies
206, 208 are depicted, each of opposite orientation. The ply path 190 in a geodesic
ply 206, 208 is initiated along what would generally be considered the bead region
198 of the carcass 194 along the tire sidewall 200 toward the shoulder region 202
of the toroidal surface 43 and then traverses across the toroidal surface 43 in
an area commonly referred to as the crown 204 as illustrated in FIG. 28. It will
be noticed that the ply cord path 190 is laid at a relatively large initial angle
of 82 to 90 degrees relative to the tire centerline at the bead region 198. The
angle of the cord path 190 changes, either gradually or abruptly along the cord
path. In the configuration shown in FIG. 28, the change is abrupt. At the shoulder
region 202, the angle of the cord &agr; decreases to a range of 17 to 27 degrees.
The angle of the ply path 190 may be chosen so that the cord ply exhibits desired
performance characteristics. The ply path 190 may consist of linear segments but
also can be applied in a non-linear fashion.
As shown in FIG. 28, once the ply cord 32 is traversed
completely across the crown 204 to the opposite shoulder 202 or sidewall 200, the
loop 196 is formed as previously discussed and the cord 32 is brought back across
the crown 204 as shown in FIG. 18. This process is repeated as the toroidal surface
43 is indexed, creating a very uniform and evenly spaced ply cord path 190.
It will further be appreciated that the cord plies 206,
208 extend from opposite bead regions 198 along respective cord paths 190A and overlap
in the crown region 204 along respective paths 190B. The angles of the cord paths
190B of the plies 206, 208 thus may extend in opposite directions. While depicted
as generally the same angle, the angle of the plies 206, 208 as each cord crosses
the crown region 204 may differ by design so as to create a combined ply structure
of specific performance characteristics. For example, without intent to delimit
the invention, the angle of the cord path 190B for ply 206 may differ in initial
magnitude, and/or magnitude at the tire centerline, from the angle of the cord path
190 B of ply 208. The shape of the cord path 190 (linear versus non-linear) of plies
206, 208 may also differ by design to construct a layered ply construction of desired
performance characteristics. Additionally, materials selected to construct the ply
cord may be selected for strength and performance criteria. Construction of one
or both of the plies 206, 208 of a strong material such as polyaramid or other materials
may be used to create a high strength ply. Layering plies 206, 208 composed of suitably
selected, high strength material, may allow for the elimination or reduction to
belt structure beneath the tread of the tire, resulting in additional cost savings.
Thus, it is within the contemplation of the invention that overlapping, oppositely
oriented cord plies may be utilized and selectively configured in one or more geodesic
patterns to meet optimal design criteria. Such a construction may operate to allow
elimination of belt packages that typically underlie the tread region of conventional
From the foregoing and FIG. 28, it will be thus be appreciated
that the present invention achieves an optimum cord ply configuration formed by
one or more geodesic cord ply layers 206, 208. Each layer is formed by a series
of spaced single line cord paths 190, each path extending an originating side of
the tire proximate the bead area 198 across the crown region 204 to an opposite
terminal tire side. The cord paths 190 each creating a loop 196 at the terminal
tire side, either at the sidewall region 200 or the shoulder region 202, and return
to the originating side. The series of spaced single line cord paths 190 combine
to form a completed cord ply layer. Each cord path 190 forms a cord angle a with
respect to the centerline of the tire that varies. In a geodesic configuration such
as shown in FIG. 28, the angle is of reduced magnitude as the path 190 crosses the
centerline of the tire.