Abstract:
A method of creating an air barrier on both sides of an innerliner splice on the inside surface of a green tire when a bladder release lubricant is being applied thereto to prevent contamination of the splice. High pressure air is directed through air nozzles on both sides of the innerliner splice just prior to and during the application of the lubricant. A pressure sensor detects high or low air pressure during the creation of the air barriers to stop the spray of lubricant should either situation be detected.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a divisional of U.S. patent application Ser. No. 10/712,875, filed Nov. 12, 2003; the disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Technical Field  
         [0003]     The invention relates to the manufacture of pneumatic tires and in particular to an apparatus and system for preventing a bladder release lubricant, which is sprayed on the innerliner of a green tire, from contaminating the innerliner splice. Even more particularly, the invention relates to the use of high pressure air for forming a barrier about the innerliner splice to prevent the release lubricant from contaminating the splice.  
         [0004]     2. Background Information  
         [0005]     During the manufacture of pneumatic tires, a green uncured tire is transferred from a tire assembly station to a spray station where a bladder release lubricant is sprayed about the interior of the tire onto the innerliner to prevent the innerliner from sticking to an inflatable bladder at a mold station to which the green tire is subsequently delivered. After the green tire has been placed in a curing mold and the mold sealed, a bladder is inflated to force the green tire against the heated mold walls whereby the tire is formed with a desired tread pattern. After a curing period, the bladder is deflated and the mold is opened and the cured tire is removed from the mold. However, problems have been encountered in that the bladder can stick to the innerliner of the tire, causing damage to the innerliner and/or bladder upon removal of the tire from the mold.  
         [0006]     Therefore, to overcome this sticking problem, the green tire is first delivered to a spray station where a release lubricant is applied to the innerliner of the tire, which is that portion which contacts the expandable curing bladder. However, this lubricant could affect the tire if allowed to penetrate the innerliner splice which could result in the tire being rejected. Therefore, to avoid this problem, a mechanical barrier, such as a flexible fabric, is placed over the innerliner splice at the spray station to prevent the lubricant from contacting and contaminating the innerliner splice. However, the use of this mechanical device or covering fabric requires maintenance and increases the cycle time at the spray station.  
         [0007]     Therefore, the need exists for an improved method and apparatus which is applied at the bladder release spray station to prevent the contamination of the innerliner splice by the sprayed lubricant, which is effective and which decreases maintenance and improves cycle time of the green tire moving through the spray station prior to entering a mold station.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a method and apparatus which is actuated and located at a spray station in a tire manufacturing process which protects the innerliner splice from contamination by bladder release lubricant applied to the innerliner of the tire at the spray station.  
         [0009]     The method and apparatus of the present invention uses a pair of high pressure air streams directed against the innerliner on opposite sides of the innerliner splice just prior and during the application of the bladder release lubricant to create an air barrier about the splice to prevent the sprayed lubricant from reaching the splice area.  
         [0010]     Another advantage of the invention is to provide a pressure sensor located downstream from the pressurized air nozzle which measures for low and high air pressure, thus detecting loss of air pressure or air nozzle blockage to insure that a required air barrier strength is created by the air nozzle. The sensor will cause the lubricant spray nozzles to be deactivated should the pressure sensor detect such high or low air pressure.  
         [0011]     Another feature of the invention is to provide an air pressure nozzle which is inserted generally axially into the tire opening and then lowered into position adjacent the bead area of the tire to form a pair of high pressure air streams which are angled outwardly downwardly from the nozzle to opposite ends of the innerliner splice which form the air barrier until completion of the lubricant spray cycle.  
         [0012]     Still another feature of the invention is the ability to mount the air spray nozzle on the existing mechanism used at the spray station for applying the release lubricant onto the innerliner, thereby avoiding complicated and expensive retrofitting of existing spray station apparatus.  
         [0013]     The foregoing advantages, construction and operation of the present invention will become more readily apparent from the following description and the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0014]     A preferred embodiment of the invention, illustrative of the best mode in which applicant contemplates applying the principles, is set forth in the following description and is shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims.  
         [0015]      FIG. 1  is a diagrammatic view of a portion of a tire manufacturing process in which the improved method and apparatus of the present invention is utilized;  
         [0016]      FIG. 2  is a side elevational view with portions of a green tire broken away and in section, showing the bladder release lubricant being applied to the innerliner of the tire, with the innerliner splice being protected by the air barrier;  
         [0017]      FIG. 3  is a diagrammatic sectional view taken on line  3 - 3 ,  FIG. 2 ;  
         [0018]      FIG. 3A  is a view similar to  FIG. 3  showing the lubricant spray nozzles and air nozzle in their lowered operating position;  
         [0019]      FIG. 4  is a fragmentary plan view of the innerliner splice looking in the direction of arrows  4 - 4 ,  FIG. 2 ; and  
         [0020]      FIG. 5  is a diagrammatic perspective view of the high pressure air supply and protection system of the present invention. 
     
    
       [0021]     Similar numerals refer to similar parts throughout the drawings.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0022]      FIG. 1  is a diagrammatic illustration of a portion of a tire manufacturing process in which tire components are assembled on a tire building drum  1  to create a green tire indicated generally at  2 . Tire  2  will have the usual toroidal configuration, and after removal from tire building drum  1  will be moved by a usual tire carrying sling (not shown) or other transfer mechanism, to a spray station indicated generally at  3 , for applying a bladder release lubricant  6  onto the inner surface or innerliner  8  of the green tire. Spray station  3  is of a usual construction of a type currently used to apply the bladder release lubricant, in combination with a mechanism for placing a mechanical cover or flap over an innerliner splice to prevent contamination thereof by the spray lubricant.  
         [0023]     As shown in  FIG. 3 , spray station  3  will include a shaft  10  along which extends one or more fluid supply lines  12  which connect to a pair of lubricant spray nozzles  14 , preferably oriented at 90° from each other, which are attached to shaft  10  by a bracket  15  for rotation within the tire as shown by arrow A in  FIG. 2 . Thus, when a green tire is moved into the spray station by a conveyor  16  or other transport mechanism, shaft  10  is moved in the direction of arrow B ( FIG. 3 ) generally axially into the central opening  18  of the tire, defined by bead areas  20 . After lubricant spray nozzles  14  have completed their spraying cycle as shown by arrow A,  FIG. 2 , shaft  10  and nozzles  14  are retracted out of their positions within tire  2 , afterwhich the tire is then moved toward a curing mold  22 . Mold  22  contains an inflatable bladder  24  which requires bladder release lubricant  6  to be applied to the innerliner of the tire to prevent sticking to the bladder after the curing operation has been completed. Heretofore, a flexible mechanical flap or cover (not shown) was moved into tire opening  18  by another shaft not shown), and then lowered radially over the innerliner splice to protect the splice.  
         [0024]     However, in accordance with the present invention, this mechanical protective shield is replaced by a high pressure air nozzle indicated generally at  28 . Air nozzle  28 , which could include a pair of nozzles  28 A and  28 B as shown in  FIG. 5 , is mounted on shaft  10  by a pair of bearings  26  and support arms  27  extending between bearings  26  and nozzle  28 . This enables shaft  12  to be rotated to spray the lubricant from nozzles  14  onto the innerliner while nozzle  28  remains in position adjacent the innerliner splice. Air nozzle  28  is formed with a pair of elongated spray orifices  30  which extend generally throughout the length of the nozzle so as to extend generally the width of the spacing between bead areas  20  of the tire as shown in  FIG. 3A . Orifices  30  form a pair of high pressure air streams  32  which extend outwardly downwardly from the nozzles so as to extend on opposite ends of an innerliner splice  34  ( FIG. 4 ) to protect the splice from the sprayed lubricant from nozzles  14 . High pressure air streams  32  form a barrier about the splice, preventing the sprayed lubricant from entering the protected area indicated at  36 , which extends about splice  34 . At the start of the spraying cycle, shaft  10  extends into the interior of tire  2  above the central axis of the tire as shown in  FIG. 3 , and then lowered radially into its operational position, as shown by arrows D, to a location just above the open spacing of the tire formed by bead areas  20  as shown in  FIG. 3A . After completion of the spray cycle, shaft  10  is raised radially in the directly of arrow D to the position of  FIG. 3  and then retracted out of opening  18  of tire  2 , enabling the tire to be moved along conveyor  16  to mold station  22 .  
         [0025]     In further accordance with the invention as shown in  FIG. 5 , spray nozzle  28  is connected to a high pressure air supply or compressor  38  by air line  40  which extends through a usual pressure regulator  42  which regulates the pressure of the incoming air. The high pressure air enters nozzle  28  through one or more pressure lines  44 . A pressure sensor  46  is mounted downstream from nozzle  28  and is connected thereto by an air line  48 . Pressure sensor  46  functions as a detector and detects whether the pressure at nozzle  28  is too high or too low with respect to a predetermined limit which indicates a loss of air pressure or blockage of the air nozzle. Should such a pressure change occur it could adversely affect air streams  32 . Thus, sensor  46  will send a signal to the lubricating fluid supply source, stopping the flow of lubricant to nozzle  14 . This insures that a sufficient air barrier is maintained about splice  34  whenever spray lubricant  6  is being applied to the innerliner of the tire.  
         [0026]     Although the above discussion refers to the use of high pressure air for creating air streams  32 , it is readily understood that other types of fluids could be used without affecting the concept of the invention. Also as indicated above, one or a pair of nozzles are utilized for forming the pair of air streams  32  which creates the desired air barrier about splice  34 , and lubricant spray nozzles  14  can have other configurations than the pair of spaced nozzles as shown in the drawings and described above.  
         [0027]     Accordingly, the improved apparatus and method of the invention enables a protective shield or barrier to be formed about an innerliner splice, preferably by using inexpensive high pressure air, which protects the innerliner splice during the spraying of the bladder release lubricant onto the innerliner of the tire at a spray station prior to the tire being placed in the curing mold. Furthermore, an air supply safety system insures that a sufficiently strong pair of air streams is provided by nozzle  28  to prevent the penetration of lubricant  6  into protected area  36  which extends about innerliner splice  34 .  
         [0028]     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.  
         [0029]     Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.