Patent Application
20080314216
This invention relates generally to an improved apparatus for manufacturing a toroidal carcass ply for a tire and, more specifically, to a cutting mechanism for cutting a cord feed line during the construction of a tire cord ply on an annular tire building surface.
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 tire is made of rubber, fabric, and steel. 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.
This form of manufacturing a tire from flat components that are then formed toroidally 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 a series of layers on a toroidal surface or core. A cord ply is formed on the core by placing and stitching one or more cords in continuous lengths onto a pre-applied 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 dispensed. Preferably, each cord, pre-coated with rubber or not so coated, is held against the elastomeric layer after the cord is placed and stitched and then indexing the cord path to a next circumferential location forming a loop end by reversing the direction of the cord and releasing the held cord after the loop end is formed and the cord path direction is reversed. The indexing of the toroidal surface establishes the cord pitch uniformly in discrete angular spacing at specific diameters.
A cord applicator head for construction of a cord ply on a toroidal surface in such a manner is disclosed in U.S. patent application Ser. No. 11/292,363, filed Dec. 1, 2005 incorporated herein by reference. The applicator head feeds a cord line between a pair of rollers positioned adjacent a toroidal tire building surface, each roller alternatively engaging and positioning the cord line as the applicator head moves back and forward across the toroidal surface. A cord ply in a preferred pattern is thus constructed on the toroidal surface. At an appropriate time in the cord application process, the cord line is severed by a cutting mechanism within the applicator head and the trailing cord line segment is paid out of the applicator head to complete a final path in the construction of the cord ply. A representative cutting mechanism within the applicator head is disclosed in U.S. patent application Ser. No. 11/291,630, filed Dec. 1, 2005 likewise incorporated herein in its entirety by reference.
While working well, certain challenges arise from the use of the cutting mechanism disclosed in application Ser. No. 11/291,630 within the applicator head of application Ser. No. 11/292,363. While a severing of the cord line within the applicator head can be timed such that the precise length of line required to complete a final cord path on the toroidal surface is achieved, a problem arises in accurately positioning the leading end of the severed cord line on the toroidal surface for a construction of the next cord ply layer. Application Ser. No. 11/292,363 teaches that the free post-cut end of the cord line may be forced from the applicator head and positioned on the toroidal surface by pneumatic pressure. In such an operation, however, it is difficult to control the free end of the severed cord and accurately initiate laying the end segment against the toroidal surface at the precise location desired. The precise location of the free end of the severed cord on the toroidal surface may, for example, be defeated if the free end segment of the cord line becomes snagged within the applicator head during the pneumatic ejection sequence. An improper or less than accurate location of the free end of the severed cord line will cause the subsequent cord pattern to begin at an incorrect location and result in a flawed cord ply. Additionally, the aforementioned difficulty in accurately locating the leading cord end on the toroidal surface not only occurs at the beginning of the cord ply construction sequence but can also occur at an interim point in the cord ply construction. For example, the cord line may break unintentionally and require replacement of the free cord end on the toroidal surface for the ply construction procedure to resume. The supply of cord may also become depleted midway through the construction of a cord ply, requiring spool replacement. Rerouting a new line of cord through the applicator head will require placement of another free cord end on the toroidal surface in order for the cord ply construction to resume.
A need, accordingly, exists for an improved method and apparatus for accurately insuring that the leading end of a ply cord line that emerges from a ply cord applicator head is precisely located at an intended initiation point on a toroidal tire building core. The improved method and apparatus should operate predictably and reliably throughout repeated cycles as multiple ply layers are constructed on the toroidal surface. The improved method and apparatus should moreover function to accurately locate the leading end of the ply cord line on a toroidal core surface both at the initiation of a ply construction sequence and at any interim point during the ply construction where such a need arises.
Pursuant to an aspect of the invention, a cord cutting apparatus is provided for remotely cutting a terminal end segment of a tire cord ply from a toroidal tire building core surface. The apparatus includes a mechanism for capturing and controlling the terminal end segment. The apparatus further provides means for tensioning the end segment between the leading and trailing segment ends and a cutting mechanism moveable toward and away from the annular tire building surface for severing the cord end segment at a point opposite an intended or target initiation point on the tire build core. In a further aspect of the invention, a segment disposal mechanism is provided for transporting a severed portion of the terminal end segment away from the toroidal tire building surface. The disposal mechanism may but need not necessarily be an integral component of the tensioning mechanism.
The tensioning mechanism in another aspect of the invention may include clamp, such as in the form of gripping fingers for effecting a clamping engagement with the terminal end segment proximate the leading end of the terminal end segment; and a wiper mechanism proximate the trailing end of the terminal end segment for axially pulling the terminal end segment away from the clamp or holding the trailing end segment against the toroidal tire building core surface, whereby placing the terminal end segment in tension between the clamp and wiper mechanism. The wiper mechanism may but need not necessarily be configured as a roller. As a further aspect of the invention, the tensioning and cutting mechanisms are moveable between first respective cutting positions proximate the toroidal tire building core surface and second retracted positions allowing unobstructed access to the toroidal tire building core surface. Construction of a tire on the toroidal tire building core surface layer by layer is therefore not impeded by the cutting apparatus.
In another aspect, the invention provides a cord cutting apparatus for cutting a terminal end segment of a tire cord ply on an annular tire building surface with the apparatus generally including a clamp and a cord cutting device. The clamp is configured to grip the terminal end segment of the tire cord ply between leading and trailing end segments, and at least assist in applying tension between the leading and trailing end segments. The cord cutting device includes a cutting element, wherein at least the cutting element is movable between a non-cutting position and a cutting position. The cutting element is adapted to be proximate the tire cord ply on the annular tire building surface to cut the tire cord ply when in the cutting position.
“Aspect Ratio” means the ratio of a tire's section height to its section width.
“Axial” and “axially” mean the lines or directions that are parallel to the axis of rotation of the tire.
“Bead” or “Bead Core” mean generally that part of the tire comprising an annular tensile member, the radially inner beads are associated with holding the tire to the rim being wrapped by ply cords and shaped, with or without other reinforcement elements such as flippers, chippers, apexes or fillers, toe guards and chaffers.
“Belt Structure” or “Reinforcing Belts” means at least two annular layers or plies of parallel cords, woven or unwoven, underlying the tread, unanchored to the bead, and having both left and right cord angles in the range from 17° to 27° with respect to the equatorial plane 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.
“Chaffers” refers to narrow strips of material placed around the outside of the bead to protect cord plies from the rim, distribute flexing above the rim.
“Cord” means one of the reinforcement strands of which the plies in the tire are comprised.
“Equatorial Plane (EP)” means the plane perpendicular to the tire's axis of rotation and passing through the center of its tread.
“Footprint” means the contact patch or area of contact of the tire tread with a flat surface at zero speed and under normal load and pressure.
“Innerliner” means the layer or layers of elastomer or other material that form the inside surface of a tubeless tire and that contain the inflating fluid within the tire.
“Normal Inflation Pressure” means the specific design inflation pressure and load assigned by the appropriate standards organization for the service condition for the tire.
“Normal Load” means the specific design inflation pressure and load assigned by the appropriate standards organization for the service condition for the tire.
“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 path.
“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.
“Radial Ply Tire” means a belted or circumferentially-restricted pneumatic tire in which at least one ply has cords which extend from bead to bead are laid at cord angles between 65° and 90° with respect to the equatorial plane of the tire.
“Section Height” means the radial distance from the nominal rim diameter to the outer diameter of the tire at its equatorial plane.
“Section Width” means the maximum linear distance parallel to the axis of the tire and between the exterior of its sidewalls when and after it has been inflated at normal pressure for 24 hours, but unloaded, excluding elevations of the sidewalls due to labeling, decoration or protective bands.
“Shoulder” means the upper portion of sidewall just below the tread edge.
“Sidewall” means that portion of a tire between the tread and the bead.
“Tread Width” means the arc length of the tread surface in the axial direction, that is, in a plane parallel to the axis of rotation of the tire.
“Winding” means a wrapping of a cord under tension onto a convex surface along a linear path.
The invention will be described by way of example and with reference to the accompanying drawings in which:
Referring initially to
The apparatus 10 is a free standing assembly including a support base plate 12, a column stand 14 mounted to plate 12; a stop mounting plate 16 vertically spaced above the base plate 12; a stop 18 mounted to plate 16; a rod coupler bracket 20 spaced vertically and mounted above the plate 16. A gusset 22 is positioned vertically above the bracket 20 and a column stand rectangular adapter plate 24 extends vertically therefrom. At the top of the apparatus an upper stop mounting plate 26 is provided mounted to the adapter plate 24. A vertically moveable linear bearing mounting plate 28 is slidably mounted to the adaptor plate 24. Mounted at a right angle to the upper end of the mounting plate 28 and extending horizontally outward is an upper mounting plate 30. A cutter mechanism mounting plate 32 is slidably mounted to move along a support plate 33 that likewise slides along a slide table 86.
A pair of elongate slide adapters 34, 36 of a type commercially available are mounted side by side to an underside of the mounting plate 32 and are coupled to work in tandem to extend a wiper mechanism to the necessary stroke required as will be explained. Mounted forward of the adapters 34, 36 is a spring plunger support block 38. Spacers 40 span between the cutter mounting plate 32 and a top mounted small slider mounting plate 42. A gripper mechanism mounting plate 44 is mounted to a forward end of the cutter mounting plate 32. A wiper support block 46 connects to the slide adapter 36 and moves therewith to extend and retract. A cantilevered arm 47 is coupled to the support block 46 and projects outward. A wiper blade 48 is rotationally mounted to the remote end of the cantilever arm 47 by means of a bearing clamp 50 and transverse shaft 52. The wiper blade 48, while in the preferred form as a roller member, may be alternatively configured if desired to accomplish its intended purpose as explained below.
Positioned at the forward end of the apparatus 10 is a gripper assembly 92 including a pair of parallel, L-shaped gripper arms 54, 56. The gripper arms 54, 56 are connected to a suitable drive mechanism within the assembly 92 (not shown) that moves the arms 54, 56 toward each other into a clamping orientation and away from each other in a de-clamped, separated orientation. Disposed and mounted below the arms 54, 56 are a pair of opposed cutter blades 58, 60. The blades 58, 60 and operably connected to a drive mechanism that closes the blades into a cutting mutual orientation and opens the blades into a divergent orientation. While in the preferred embodiment the blade 58 rides over the blade 60 to effect a cut, while blade 60 remains fixed and stationary, other alternative cutting movements between the blades or the use of other blade or cutting devices may be utilized if desired.
The cutting tooling mounted at the top of the cutting apparatus 10 is referred herein generally by numeral 62. The tooling 62 moves along a horizontal axis between an extended position required for conducting a cutting procedure and a retracted position between cuts. As best viewed from
The linear bearing mounting plate 28 (reference
Generally, the wiper subassembly 90 is mounted at the bottom, the cutter sub-assembly 88 in the middle; and the gripper arm-sub-assembly 92 at the top. The plate 33 extends along the Y-axis, riding upon a rail 112. Stop 114 is situated to engage the plate 33 as it reaches the terminal end of a retraction stroke. The apparatus 10 thus extends and retracts vertically along a Y-axis and extends and retracts along an X-axis to move the upper assembly 62 into appropriate position for sequential operation of the subassemblies 88, 90, and 92 as will be explained.
As will be apparent from
Details of the gripper subassembly 92 are shown in FIGS. 4 and 4A-C. The gripper arms 54, 56 include opposed forward end surfaces 116, 118. The surfaces 116, 118 move with the arms toward each other in direction 120 into a gripping relationship of suitable spacing to clamp to and hold fast a portion of tire cord. The surfaces 116,118 likewise move apart with respective arms 54, 56 to retract from a gripping relationship under machine control. As will further be appreciated, the wiper member 48 carried by cantilever arm 47 moves in direction 122 to extend and retract. The slide adaptors 34, 36 cooperate to provide the wiper member 48 with the desired stroke length. Plate 32 carries the upper apparatus 62 in a movement along the X-axis as indicated by directional arrow 124. In addition, the plate 32 and apparatus 62 are carried on plate 33 along a path indicated at arrow 126.
Apparatus 62 as shown in
With reference to
In order to create the desired pattern 144, the leading free end of the cord line 130 must be precisely located on the core 142 at a targeted initiation point. However, for reasons described previously, it is difficult to control the free end of the cord line 130 as it is fed from the applicator head 148. Accordingly, in order to initiate a cord ply at the exact point on the core desired, a leading end segment 130 is fed from the applicator head to the core so as to overlay or extend past the desired or intended initiation point of the cord line 148. The leading cord end segment 130 remains over the initiation point on the core until after the cord ply is fully constructed. At the conclusion of the cord ply construction, a cutting step is conducted to precisely sever the free cord end segment 130 at the intended initiation point utilizing the cutting apparatus 10. The leading cord end segment 130 is at this point severed by the cutting apparatus 10 leaving the initiating end of the cord ply at precisely the intended initiation point on the core.
Operation of the cutting mechanism 10 is illustrated sequentially in
Wiper member 48 is then retracted a distance in the direction 162 as shown in
As will be appreciated from
From
The clamping or gripping fingers 54, 56 maintain clamped control over the severed cord leading end segment 132 as the apparatus 62 is withdrawn. After the apparatus 62 is retracted, the gripping fingers 54, 56 are opened to discharge the cord leading end segment 132 away from the build core 142. The risk of segment 132 becoming inadvertently attached to the build core 142 or to the tire layers constructed on the core is thereby prevented. The point P shown in
While the initiation point P (
From the foregoing, it will be appreciated that the apparatus 10 represents an illustrative apparatus for accurately insuring that the leading end of a ply cord line from a ply cord applicator head is precisely located at an intended initiation point on a toroidal tire building core. The apparatus 10 operates predictably and reliably throughout repeated cycles as multiple ply layers are constructed on the toroidal surface. The apparatus functions to accurately locate the leading end of the ply cord line on a toroidal core surface, whether at the initiation of a ply construction or at any interim point during the ply construction where such a need arises.
In addition, the apparatus 10 operates according to a method wherein a free end of a ply cord line is positioned over an initiation point P on a tire build core; the ply cord end segment is captured and controlled by apparatus components engaging a leading segment end and a trailing segment; the end segment is axially aligned and placed in tension between the leading and trailing ends; and the end segment is severed precisely at an intended initiation point P. The method further includes retracting the apparatus away from the tire build core, leaving the core unobstructed and accessible for subsequent tire build operations. The method also may include retaining control over a severed portion of the cord line end segment and moving the severed portion away from the tire build core for disposal as the apparatus retracts.
Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.
