Abstract:
An apparatus for applying a strip of elastomeric material to a surface, the apparatus comprising: a nozzle having an inlet in fluid communication with a pumping means, said nozzle having an upper surface and a lower surface, wherein the lower surface has a curved shape for mating engagement with an outer surface of a rotatable roller, said lower surface having an opening positioned for engagement with the roller outer surface.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to an apparatus for forming an elastomeric strip. 
       BACKGROUND OF THE INVENTION 
       [0002]    It is well known in the prior art to manufacture tire components from elastomeric sheets of rubber which are then cut to length with the ends joined together by a lap or butt splice onto a cylindrically shaped building drum. Since the tire components are assembled flat onto a cylindrical tire building drum and then expanded into a toroidal shape, each component has to be placed in tension or compression prior to being molded. This stretching of the various parts causes slippage between the various rubber parts as the components heat up during vulcanization. Attempts to minimize the slippage of the various parts have been attempted. Another disadvantage is that the tire has components which are spliced, wherein the splices contribute to tire nonuniformity. 
         [0003]    Tire manufacturers have been increasingly focusing their efforts on eliminating tire nonuniformities. More recently, tire manufacturers are making tire components from a continuous strip of unvulcanized rubber. A thin, narrow strip of unvulcanized rubber is circumferentially wound multiple times onto a rotating drum or toroid shaped core, wherein the strips are successively layered or stacked in order to form the desired shape of the tire component. See for example, U.S. Pat. Nos. 6,372,070 and 4,963,207. The strip of rubber is typically extruded directly onto a tire building drum or toroidal-shaped core using an extruding device. Alternatively the strips may be formed from calendering and then conveyed to the tire drum or core. 
         [0004]    This strip lamination method of forming tire components has the advantage of eliminating splices because the annular tire component is typically formed of one continuous strip. Strip lamination has the further advantage of allowing flexibility in manufacturing, since the tire component profile may be changed from tire to tire. 
         [0005]    It is known to extrude the rubber through a nozzle or shaping die and to apply the strip of rubber using a roller or stitcher to a tire building drum. However, these systems typically have the disadvantage of causing high pressure and high temperature of the rubber in the system due to the small exit area opening. If the residence time of the rubber is too slow through the system, the rubber may be scorched if the temperature is too high. Thus it is desired to have an improved system which will lower the system temperature and pressure while forming the desired shape of the rubber strip. 
       Definitions 
       [0006]    “Aspect ratio” of the tire means the ratio of its section height (SH) to its section width (SW); 
         [0007]    “Axial” and “axially” means lines or directions that are parallel to the axis of rotation of the tire; 
         [0008]    “Bead” means that part of the tire comprising an annular tensile member with or without other reinforcement elements such as flippers, chippers, apexes, toe guards and chafers, to fit the design rim; 
         [0009]    “Belt reinforcing structure” means at least two layers of 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 degrees to 27 degrees with respect to the equatorial plane of the tire; 
         [0010]    “Carcass” means the tire structure apart from the belt structure, tread, under tread, and sidewall rubber over the plies, but including the beads; 
         [0011]    “Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction; 
         [0012]    “Chafers” 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, and to seal the tire; 
         [0013]    “Chippers” means a reinforcement structure located in the bead portion of the tire; 
         [0014]    “Cord” means one of the reinforcement strands of which the plies in the tire are comprised; 
         [0015]    “Design rim” means a rim having a specified configuration and width. For the purposes of this specification, the design rim and design rim width are as specified by the industry standards in effect in the location in which the tire is made. For example, in the United States, the design rims are as specified by the Tire and Rim Association. In Europe, the rims are as specified in the European Tyre and Rim Technical Organization—Standards Manual and the term design rim means the same as the standard measurement rims. In Japan, the standard organization is The Japan Automobile Tire Manufacturer&#39;s Association. 
         [0016]    “Equatorial plane” (EP) means the plane perpendicular to the tire&#39;s axis of rotation and passing through the center of its tread; 
         [0017]    “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; 
         [0018]    “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; 
         [0019]    “Net-to-gross ratio” means the ratio of the tire tread rubber that makes contact with the road surface while in the footprint, divided by the area of the tread in the footprint, including non-contacting portions such as grooves; 
         [0020]    “Normal rim diameter” means the average diameter of the rim flange at the location where the bead portion of the tire seats; 
         [0021]    “Normal inflation pressure” refers to the specific design inflation pressure and load assigned by the appropriate standards organization for the service condition for the tire; 
         [0022]    “Normal load” refers to the specific design inflation pressure and load assigned by the appropriate standards organization for the service condition for the tire; 
         [0023]    “Ply” means a continuous layer of rubber-coated parallel cords; 
         [0024]    “Radial” and “radially” means directions radially toward or away from the axis of rotation of the tire; 
         [0025]    “Radial-ply tire” means belted or circumferentially-restricted pneumatic tire in which the ply cords which extend from the bead to bead are laid at cord angles between 65 degrees and 90 degrees with respect to the equatorial plane of the tire; 
         [0026]    “Section height” (SH) means the radial distance from the nominal rim diameter to the outer diameter of the tire at its equatorial plane; and, 
         [0027]    “Section width” (SW) 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. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    The invention will be described by way of example and with reference to the accompanying drawings in which: 
           [0029]      FIG. 1  is a perspective view of a rubber applicator apparatus of the present invention. 
           [0030]      FIG. 2  is a close-up perspective view of a roller and nozzle of the rubber applicator apparatus of the present invention. 
           [0031]      FIG. 3  is a side cross-sectional view of the apparatus of  FIG. 1 . 
           [0032]      FIG. 4  is a close-up side view of the roller and nozzle wherein the nozzle is shown with half the nozzle removed; 
           [0033]      FIG. 5  is a side view of the nozzle; 
           [0034]      FIG. 6  is a perspective view of the nozzle outlet; 
           [0035]      FIG. 7  is an end view of the outlet of the nozzle; 
           [0036]      FIG. 8  is a side view of the rubber applicator apparatus shown applying a rubber strip to a tire building drum. 
           [0037]      FIG. 9  is a side view of the rubber applicator apparatus showing the axis of rotation. 
           [0038]      FIG. 10  is a side view of a first embodiment of a rotatable nozzle and rubber applicator apparatus showing the axis of rotation. 
           [0039]      FIG. 11  is a side view of a second embodiment of a rotatable nozzle and rubber applicator apparatus showing the axis of rotation. 
           [0040]      FIG. 12  is a side view of a third embodiment of a rotatable nozzle and rubber applicator apparatus showing the axis of rotation. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0041]    A first embodiment of a rubber applicator apparatus  100  is shown in  FIGS. 1-7 . The applicator apparatus  100  provides a novel apparatus to form elastomeric tire components quickly and efficiently from a single continuously wound strip or multiple strips of unvulcanized rubber. A continuous strip of unvulcanized rubber may be applied directly onto a tire building surface such as a tire building drum A as shown in  FIG. 8 , or a toroidal shaped core (not shown). 
         [0042]    As shown in  FIG. 1 , the applicator apparatus  100  includes a support frame  110  (parts of which have been removed for clarity), and a roller nozzle  200 . The support frame may further include support rails for translating the entire applicator apparatus in the X, Y and Z direction (not shown).). A rotatable linkage  111  is mounted to the support frame  110 , and functions to pivot the roller  300  about fixed point  114  as shown in  FIG. 4 . The rotatable linkage  111  is connected to actuator arm  112  which translates fore and aft to pivot the rotatable linkage  111  about the fixed point  114 , so that the roller may likewise be pivoted. 
         [0043]    As shown in  FIG. 3 , the support frame  110  includes a mounting flange  102  for connecting to a rubber pumping means such as an extruder, gear pump, extruder-gear pump combination, or rubber injector (not shown). The rubber or elastomer output from the rubber pumping means is fed into an internal passage  103  of the mounting flange and then into a transition member  120 . The transition member  120  has an interior channel  126  having an inlet end  122  and an outlet end  124 . The inlet end  122  preferably has a larger area than the outlet end  124 , resulting in a decreasing area or a funnel-shaped channel  126 . Channel  126  is also angled downwardly in the range of about 30 to about 75 degrees with respect to the X axis, more typically about 45-60 degrees. The outlet end  124  of the transition member is connected to an inlet end  202  of a nozzle  210 . 
         [0044]    The nozzle  210 , as best shown in  FIGS. 3-7 , has a generally cylindrically shaped outer body  211  terminating in an angled face  212  at the nozzle outlet  223 . The nozzle has an interior channel  221  that has a decreasing area from the inlet end  202  to the outlet orifice  223  of the nozzle. The angled face  212  of the nozzle terminates in an edge  214 . The edge  214  forms a juncture between the angled face  212  and a curved outlet surface  230  of the nozzle. The lower surface of the edge  214  has a shaped die surface  216  that cooperates with the curved outer surface of the roller  300  to form the nozzle outlet. The shaped die surface  216  in this example, has a flat edge  217  with opposed beveled ends  218 , 219  which forms a strip with beveled edges. The die shape is not limited to the configuration shown, and may form other shapes as desired. The curved lower surface  230  of the nozzle is shaped to cooperate with the outer surface of roller  300  in order to form the strip. The lower surface of the nozzle has an opening  231  that is preferably v shaped. The opening  231  has an axial width A and a longitudinal length L, wherein the length is greater than 1.5 times the axial width A. The opening  231  is wide to allow the rubber to engage the outer surface of the roller  300  before exiting the outlet  232 . The wide opening allows the rubber or elastomer to engage the outer surface of the roller. As the roller  300  rotates, the outer surface of the roller  300  engages the rubber flowing through the nozzle, and pulls the rubber towards the nozzle outlet  232 . The pulling of the rubber by the roller lowers the internal pressure and temperature of the rubber as it travels through the system  100 . The lower extrusion temperatures reduce stretch of the rubber. As the rubber is pulled towards the nozzle outlet  232 , it is shaped by die surfaces  217 , 218 , 219  of the upper edge  214  and the roller outer surface  300 . Preferably, the roller  300  is heated. 
         [0045]    The outlet die surfaces  217 , 218 , 219  of the nozzle is shown with a trapezoidal shape, however other configurations may be used such as, but not limited to, square, rectangular, triangular, etc. The width of the rubber strip output from the nozzle orifice is typically about 15 mm in width, but may vary in the range of about 5 mm to about 30 mm. The nozzle  212  may be optionally heated to a temperature in the range of about 0 to about 200 degrees F. using external or internal heaters (not shown). 
         [0046]    As shown in  FIG. 8 , the nozzle  210  is oriented with respect to the tire building drum A, core (not shown) or other application surface typically at an angle β in the range of about 0 to about 50 degrees, more typically in the range of about 20-35 degrees. The rubber from the nozzle is first adhered to the roller  300 , and then pushed through the nozzle outlet and then applied by the rotating roller  300  to the tire building drum A, as shown in  FIG. 8 . A stitcher roller  400  is positioned adjacent the roller  300 , and applies pressure to secure the strip onto the drum. The stitcher roller  400  is attached to link arm  402 , that is pivotally connected to the support frame  110 . The stitcher roller  400  is connected to actuator arm  404  connected to actuator  406 . 
         [0047]    The roller assembly  300  preferably has internal heaters for heating the outer surface in the range of about 200 to about 400 degrees F., and more preferably in the range of about 350 to about 400 degrees F. Thus the roller functions as a hot knife, smoothing and smearing the freshly deposited rubber, melting and blending the adjacent strips of rubber together, into a homogeneous mass. The higher roller temperature does not impact the curing of rubber due to the short residence time. The stitcher assembly  400  performs a stitcher function due to the pressure of the roller against the drum, smoothing out the air pockets. The outer surface of the roller also helps shape the formed component. 
         [0048]    The roller assembly  300  preferably is connected to a linkage system  500  connected to an air cylinder as shown in  FIG. 4 , so that the roller  300  may be raised and lowered. 
         [0049]    It is further desired that the roller nozzle  210  and roller  300  may be rotated about an axis A-A as shown in  FIG. 9 . The rotation or swiveling about axis A-A is useful to allow application of a rubber strip to sidewalls of a tire and other components with difficult geometrical limitations.  FIG. 10  illustrates a first embodiment of a roller nozzle  210  and roller  300  about axis A′-A′. In order to facilitate the rotation of the nozzle  210  about axis A′-A′, the outlet end  124  of the nozzle is connected to a flexible coupling  600 . A first end  602  of the flexible coupling is rotatably connected to the outlet end  124  of the nozzle. A second end  604  of the flexible coupling is rotatably connected to the inlet end  103  of the mounting flange. The roller nozzle  210 , roller  300  is connected to a support bracket  330  that is rotatably mounted to gear box and motor to allow rotation of the roller nozzle, roller  300  and support bracket about the Axis A′-A′. The roller nozzle, roller and support bracket is able to rotate at least +/−15 degrees. 
         [0050]      FIGS. 11 and 12  illustrate a second embodiment of a rotatable nozzle assembly  210  and roller  300 . As shown in the figures, a rotatable coupling  700  is inserted between the between the inlet of the nozzle and the outlet of the transition member. The transition member is fixed, while the nozzle and roller is rotatable about axis A-A. 
         [0051]    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.