Abstract:
Disclosed is a machine for rotation of the bead area of a green tire so that the bead areas are parallel and concentric in order to remove potential anomalies that can occur to a green tire bead portion during pre-cure handling, storing or during shaping in the tire press. The tire apparatus orients the beads of the green tire parallel and square to one another and also rotates the bead area of the tire into the proper configuration prior to cure. The bead portions of the tire maintain the parallel position as the tire is loaded into a tire mold. Also disclosed is a tire loader that has a bead support ring and paddles to grip the outer crown portion of the tire.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to tires and tire machinery. More particularly, the present invention is directed to a machine that reduces nonuniformities of a green tire. 
     BACKGROUND OF THE INVENTION 
     Tire uniformity is important to overall performance. Non-uniformities may occur during the tire building process, green tire storage, or during loading and shaping of the green tire into the tire press prior to curing. One aspect of tire non-uniformity is when the opposed tire beads are not concentric and parallel to each other. As shown in  FIG. 1 , a prior art green tire loader grasps the tire from the top bead and positions the lower bead onto a bottom mold bead ring in the press. Next, the top bead is released without control of its location relative to the bottom bead, or the top mold bead ring. One problem with the prior art loader is that the lower sidewall bead region has not been rotated into cured position prior to engagement with the tapered bottom bead ring, and the loader is incapable of improving this undesirable condition. A second problem is that the green tire may or may not be centered on the loader or the bottom bead ring in the mold. A third problem is that the prior art tire loader has no means to accurately hold the top bead of the green tire concentric or parallel to the bottom bead. 
       FIG. 2   a  illustrates a green tire having a bead seated on the bottom mold bead ring  12  prior to shaping and with the mold in the open position. At this point, dimension X is equal to dimension Y. As shown, the lower sidewall bead region  14   a  is constrained by the bottom mold bead ring  12 , while the top sidewall bead region  14   b  is unconstrained.  FIG. 2   b  illustrates the green tire during shaping of the curing bladder.  FIG. 2   b  also illustrates that the lower ply endings A near the bottom mold bead ring are trapped between the bladder and the tapered bottom mold bead ring, thus severely restricting the lower sidewall area from rotating into the proper position. During bladder shaping the mold is not closed allowing the upper bead area to be unrestrained. As the shaping pressure increases, the upper ply endings B are pulled back around the bead resulting in an increase in the Y dimension. The increase in the Y dimension also causes the centerline of the tire to shift laterally from the desired centerline a distance L, further causing conicity. Thus as shown in  FIG. 2   b , dimension Y is greater than X resulting in tire non-uniformity. When the press closes, the top mold bead ring engages the top bead, and forces the material in the top bead area to rotate around the top bead. The non-uniformity of material rotation around the top bead is similar to that of the bottom bead. Closing of the curing press does not solve the issues described above, and a tire with non-uniformity issues may still be cured. 
     It is thus desired to provide an improved apparatus for preforming the green tire prior to entry into the mold to ensure that the tire beads are concentric and parallel to each other. It is further desired to provide an improved apparatus that ensures the top and bottom bead areas are rotated into the proper cured position prior to placement into the tire mold and when loaded into the mold. 
     SUMMARY OF THE INVENTION 
     The invention provides in a first aspect a green tire preformer apparatus for rotating the bead areas of the tire into alignment with respect to each other, the green tire preformer apparatus includes a first support having a first bead ring to support a first tire bead area of a green tire, the green tire having opposing first and second tire bead areas, and a second support having a second bead ring positionable for engagement with the second tire bead area; and first and second rotatable bead clamps, wherein the first and second rotatable bead clamps are positioned to clamp the first and second bead areas into engagement with the first and second bead rings, respectively. The invention provides in a second aspect, a tire loader that has had a bead support ring and paddles to grip the outer crown portion of the tire. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described by way of example and with reference to the accompanying drawings in which: 
         FIG. 1  illustrates a prior art loader loading a green tire into a tire press. 
         FIG. 2   a  is a cross sectional view of a green tire partially mounted on the bottom mold bead ring prior to engagement of the shaping bladder and mold closing; 
         FIG. 2   b  is a cross sectional view of a green tire partially mounted and shaped on the bottom bead ring of the tire mold during bladder shaping; 
         FIG. 3  is a cross sectional front view of a green tire pre-former of the present invention shown in the start position without a green tire; 
         FIG. 4  is a cross sectional front view of a green tire pre-former of the present invention shown in the start position with a green tire and green tire loader; 
         FIGS. 5 and 5   a  are cross sectional views of the bottom mold bead ring support with translating support ring; 
         FIG. 6  is a cross sectional front view of a green tire pre-former of the present invention shown in the loaded and lowered position with a green tire and green tire loader; 
         FIG. 7  is a cross sectional front view of a green tire pre-former of the present invention shown with the loader upper mold bead support ring engaging the top bead of the green tire prior to the material rotation around the beads; 
         FIG. 8  is a cross sectional front view of a green tire pre-former of the present invention shown in the actuated/clamped position, after rotating the bead area material around both the top and bottom beads but prior to the loader grasping the outside diameter of the green tire; 
         FIG. 9  is a cross sectional front view of a green tire pre-former of the present invention shown with both bead areas rotated and the green tire grasped in the loader for transport; 
         FIG. 10   a  illustrates the green tire prior to shaping or lower bead area rotation; 
         FIG. 10   b  illustrates the green tire after upper and lower bead area rotation, but prior to shaping. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 3  illustrates a green tire pre-former apparatus  200  of the present invention. The green tire pre-former apparatus  200  is useful for pre-forming a green tire so that the overall tire shape matches the cured tire shape, and the tire beads are concentric and parallel with respect to each other prior to entry into the mold. The tire pre-former apparatus  200  comprises a support frame  202  that has three or more support legs  204  joined together by a stationary lower support plate  206 . An annular center support outer column  220  extends vertically upwards from the support plate  206  guiding center support inner column  222 . A lower spider ring  208  is slidably mounted on center support outer column  220 . Support frame  202  further comprises a stationary upper support plate  210  that is connected to the lower support plate via a plurality of support frame columns  209 . 
     The green tire pre-former apparatus  200  further comprises a lower bead support ring  230 . The lower bead support ring  230  is shown in  FIG. 3  in a raised position suitable for loading the green tire onto the pre-former apparatus. As best shown in  FIG. 5   a , the lower bead support ring  230  has a lower surface mounted to an upper ring  231 . The upper ring may be optionally connected to a rotatable bearing  237  so that the upper ring is free to rotate. The rotatable bearing  237  is connected to a bearing support plate  239 . The lower surface of the bearing support plate  239  is mounted to a distal end  232  of a translating rod  235 . Thus the lower bead support ring may be raised and lowered via translating rods  235 , and may also be rotated radially around the center column via rotatable bearing ring  237 . A gear rack  243  is positioned for engagement with the rotatable bearing ring  237  in order to precisely position the lower bead support ring  230 . A programmable rotation-positioning device  244  may optionally be used to position the rotatable bearing ring  237 . 
     The lower bead support ring  230  as shown in  FIG. 5A  has a bead support  232  extending radially outward from the support ring  230 . The bead support  232  has an annular lip  234  located axially inward of the bead support. The annular lip is straight and has no taper. The bead support has a flat portion  236  located axially outward on the support ring. The bead support  232  further comprises an angled seat  238  that joins the annual lip  234  to the flat portion  236 . The angled seat  238  helps cam over the bead area material into the proper cured alignment position. The green tire pre-former apparatus  200  further comprises a top hat  245  which facilitates the proper centering of the green tire bead and tire onto the lower bead support ring of the green tire pre-former apparatus.  FIG. 4  illustrates a green tire loaded onto the green tire pre-former apparatus with support ring  231  in the raised position with the lower sidewall bead area of the green tire in mating engagement with the lower bead support ring  230 . 
     After the green tire has been lowered on the green tire pre-former apparatus  200  as shown in  FIG. 6 , the green tire loader  100  is lowered into the support/grasp position around the green tire as shown in  FIG. 7 . The green tire loader  100  includes an upper support ring  102  for engaging and supporting the upper bead of the green tire. The upper support ring  102  may optionally be rotatable, as described in more detail, below. The loader  100  with a rotatably mounted upper support ring  102  is lowered until the inner radial lip  106  of the upper bead support ring  102  engages the top bead of the green tire. The green tire loader further includes a plurality of tire engaging paddles or chucks  110 . Each tire chuck is independently radially movable on a rail support  112  connected to a pneumatically driven piston  114 . Each chuck is lockable at its own unique tread radius position thus holding and maintaining the concentricity of the top tire bead to the top bead lip ring  102 .  FIG. 6  shows the upper bead support ring  102  mounted on a support structure  116  in order to stabilize the support ring, facilitate bead size, provide for ring size changes, and position the support ring  102  adjacent to the tire engaging chucks  110 . 
     As shown in  FIG. 7 , the green tire pre-former device further comprises upper and lower bead clamps,  300  and  400 , which rotate and engage the inner tire bead area  302  and  402 , thus causing the green tire bead area components  302  and  402  to rotate around the upper and lower bead support rings  230 ,  102  (including their angled seats  238 , and their straight, non-tapered annular lips  234 ,  106 ) until the inner tire bead areas  302 ,  402  are held securely against the flat areas  236 . The bead area components are able to rotate around the bead ring because the support rings  102 , 230  have no tapered lips which prevent the rotation. The bead area components  302 , 402  are the tire components that are rotated around the bead ring, which include the rim strip, inner liner, apex, the ply, and typically the lower sidewall below the turnup. Depending on tire design, other components around the bead area will also be rotated. 
     A plurality of upper and lower bead clamps  300 ,  400  are arranged in an annular fashion and are positionable to engage the tire bead area components  302 , 402 . The upper and lower bead clamps  300 , 400  may each comprise at least eight equally spaced rotatable bead clamps. The bead clamps  300 , 400  include curved or L shaped fingers that are adjustable in length, and function to grip the tire bead area components  302 ,  402  into engagement with the support rings  102 ,  230 . The fingers may be articulable. The bead clamps  300 , 400  are pneumatically actuated in multiple partial steps, performed sequentially that ultimately result in the complete uniform rotation of the tire bead area components  302 ,  402  into engagement with the flat areas  236  of the bead support rings  102 , 230 . The bead clamps are pivotally mounted to support flanges  304  and  404 . The lower bead clamps  400  are positioned in an annular arrangement adjacent to the lower bead ring  230 . The lower bead clamps rotate about pin  408  of flange  404 . The upper bead clamps rotate about pin  308  of flange  304 . Flanges  404  are mounted to the support plate  210  of the tire pre-former. The lower bead clamps include a bead clamp pivot  410  having an outer end rigidly connected to the bead finger  403  and an inner end pinned to the support flange  404 , so that rotation of the bead clamp pivot  410  rotates the bead finger  403  about pin  408 . Bead clamp pivot  410  has a distal end connected to arm  430 . Arm  430  is pin connected to lower spider ring  208 , which slides on center support outer column  220 . Thus rotation of the lower bead area into the desired shape occurs during actuation of the arms  430  via sliding spider ring  208  pushed by pneumatic actuator  415 . 
       FIG. 8  illustrates the upper and lower bead clamps after being rotated into position so that the bead area components  302 ,  402  engage with the upper and lower bead rings  102 ,  230 . This position is held for a period of time sufficient for the green tire to retain its shape, typically in the range of about 2 to about 10 minutes. The time may vary depending upon the particular tire size and components used. Next, the upper and lower bead clamps are unclamped, and the upper and lower bead support rings are rotationally indexed, and then the clamps are actuated. The above steps are repeated until the green tire has rotated a complete circle. 
       FIG. 9  illustrates the green tire loaded in the loader  100  after removal from the pre-former  200 . The loader  100  grips the outer radial surface of the tread region of the green tire. The upper bead area of the green tire is still in engagement with the rotatable upper bead ring support  102  to ensure the bead area  302  remains concentric to the bead center and supported during entry of the curing bladder at shaping. 
     The green tire loader  100  has been designed to engage the tire without negatively affecting lower bead area rotation or bead concentricity and parallelism. The tire loader  100  has several features built in to enhance uniformity. First when grasping the green tire for transport to the press, the loader  100  tire chucks grip only the crown of the outside of the tread area. Prior art loaders grasp the inside of the top bead that would cause a negative rotation of the material around the top bead. Typical prior art loader fingers do not address concentricity of either the top or bottom bead, so as a result parallelism of the two beads is also at risk. The loader  100  maintains the centering of the bottom bead by using multiple independently lockable cylinders to grasp the tread crown without distorting the upper and lower bead center to tread relationship. Finally the loader  100  contains the top bead ring support that maintains rotation, concentricity, and parallelism, during curing bladder shaping, and the transfer of the green tire to the curing press. 
       FIG. 10   a  illustrates a typical green tire prior to being shaped. The bead areas of the green tire have a reverse curvature as compared to the green tire of  FIG. 10   b . In  FIG. 10   b , the beads are located axially inward of the tread shoulders, as compared to  FIG. 10   a  in which the beads are located axially outward of the tread shoulders. The lower sidewall of  FIG. 10   a  has angle of about 120 degrees with the axis of rotation, while the lower sidewall of  FIG. 10   b , which is more consistent to the cured tire position, has an angle of about 60 degrees. 
     While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art that the various changes and modifications may be made therein without departing from the spirit or scope of the invention.