Abstract:
A tire bead holder assembly for centering and gripping a circular tire bead before placement on a bead setter has circumferentially spaced radially moveable fingers actuated by a chain drive for simultaneous controlled movement of the fingers and application of centering pressure without distortion of the bead.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of Invention  
           [0002]    This invention relates to tire building and especially centering and placing a circular tire bead on a bead setter for application to a tire carcass built on a tire building drum.  
           [0003]    2. Description of the Related Art  
           [0004]    In the building of a tire, a bead or bead apex assembly is fabricated at a position away from the tire building drum and then applied to the plies which have been positioned on the tire building drum during revolutions of the drum. At the time the bead or bead apex assembly is applied to the tire casing which has been built on the drum, it is important that the beads be set in a cylindrical configuration and in a centered position relative to the cylindrical drum on which the carcass is built. It has been found that this operation cannot be done manually with the necessary precision and therefore a tire bead holder is needed for gripping the circular tire bead and placing the bead in a circular condition at a concentric position on a bead setter. The bead is held on the bead setter by magnets in the position it is received and is then carried to the tire building drum where it is applied to the tire carcass. In U.S. Pat. No. 4,726,861 a tire bead centering and feeding apparatus is proposed where the beads are supported and centered on hinged arms having bead supporting fingers which engage the bead as the hinged arms are moved about a swinging axis. The movement of the hinged arms causes the fingers to be applied unevenly which may result in deviations in the centering of the bead.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention is directed to an improved tire bead holder assembly in which the bead holding fingers are moved simultaneously and equally in a radial direction to center and hold the bead or bead apex assembly. A direct drive chain is connected to radially moveable slides for supporting the fingers providing substantially equal centering forces on circumferentially spaced portions of the bead. A simple piston cylinder assembly connected to the chain drive provides the simultaneous movement of the fingers.  
           [0006]    In accordance with one aspect of the invention, there is provided a tire bead holder assembly for gripping a circular tire bead and placing the bead in a concentric position on a bead setter comprising a supporting disk, a plurality of circumferentially spaced radially extending linear guide members on the disk characterized by slide members mounted on each of the guide members, each of the slide members having an axially extending bead holding finger for engaging the bead and a radially moveable drive means in engagement with each of the slide members for moving each of the slide members and each axially extending finger radially into and out of engagement with the tire bead.  
           [0007]    In accordance with another aspect of the invention, there is provided a method of holding and positioning a tire bead for transfer to a bead setter from a bead holder comprising:  
           [0008]    a. placing the bead over a plurality of circumferentially spaced fingers mounted on radially moveable slide members;  
           [0009]    b. moving said slide members with a chain adjacent and attached to each of the slide members to provide simultaneous radially outward movement of each of the fingers into centering and gripping engagement with the bead.  
           [0010]    c. applying pressure by the fingers on the bead with the forces from the chain applied by a piston cylinder assembly;  
           [0011]    d. moving the fingers into an opening in the bead setter providing for engagement of the bead with the bead setter in a centered position;  
           [0012]    e. applying a retaining force on the bead by the bead setter;  
           [0013]    f. releasing the bead by moving the fingers radially inward; and,  
           [0014]    g. retracting the bead holder from the bead setter;  
           [0015]    Still other benefits and advantages of the invention will become apparent to those skilled in the art to which it pertains upon a reading and understanding of the following detailed specification. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and herein:  
         [0017]    [0017]FIG. 1 is a view in perspective of the bead holder embodying the invention showing a bead apex assembly with parts being broken away centered and held in position on the bead holder.  
         [0018]    [0018]FIG. 2 is a front view of the bead holder with the cover removed.  
         [0019]    [0019]FIG. 3 is a sectional view taken along the line  3 - 3  in FIG. 2.  
         [0020]    [0020]FIG. 4 is a sectional view taken along the line  4 - 4  in FIG. 2.  
         [0021]    [0021]FIG. 5 is a schematic side elevation showing the transfer of the bead from the bead holder to the bead setter.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]    Referring to FIG. 1 a tire bead holder assembly  10  is shown supporting a bead  12  and apex  14  which have been fabricated at another location and hung over bead holding fingers  16  at circumferentially spaced positions around the bead holder assembly  10 . A cover  18  is mounted on a supporting disk  20  and has slots  22  through which the fingers  16  extend. As shown in FIGS. 2 and 3, the fingers  16  are mounted on slide members  24  each of which is slidably mounted on a linear guide member  26  fastened to the disk  20  at circumferentially spaced positions in a radially extending direction. As shown in FIG. 4 each of the slide members  24  may have a slot  28  with ribs  30  for sliding engagement with slide grooves  32  in the guide member for guiding the radial movement of the slide member  24 .  
         [0023]    As shown in FIGS. 2, 3, and  4  a chain  34  is guided by sprockets  36  over a drive path extending alongside each of the slide members  24  which are connected to the chains by clamps  38  to provide for simultaneous radial movement of the slide members and the fingers  16  as the chain  34  is moved by a suitable power means such as piston cylinder assembly  41  shown in FIG. 3. A piston  43  of the assembly  41  is mounted on the disk  20  and the moveable cylinder  45  has a saddle member  47  with a hook  49  attached to a first end  51  of the chain  34  and an adjustable connection  53  connected to the second end  55  of the chain. Suitable connections to the piston cylinder assembly  41  provide for moving the cylinder  45  carrying the saddle  47  with the chain  34  between positions A and B causing the slide members  24  to move radially carrying the fingers  16  into engagement with the bead  12  by regulating the pressure in the cylinder  45 . The force applied by the finger  16  to the bead  12  can be adjusted so that there is no distortion of the bead  12  and apex  14  as it is being grasped by the tire bead holder assembly  10 .  
         [0024]    Referring to FIG. 1 the fingers  16  are mounted on the slide members  24  by threading a socket  57  in each of the fingers over threaded studs  59  on the surface of the slide members  24 . The studs  59  may be spaced radially for mounting the fingers  16  at different radii such as 13 inches (33.02 cm) and 17 inches (43.18 cm).  
         [0025]    In operation the tire bead holder assembly  10  may be mounted on a suitable conveyor  61  shown schematically in FIG. 5 for carrying the bead  12  and apex  14  into engagement with a bead setter  63  shown in section which may have magnets  65  for holding the bead  12 . In a centered position ready for application to the tire building drum by the bead setter. After the application of the bead  12  to the bead setter  63  the fingers  16  may be retracted radially by actuating the piston cylinder assembly  43  and the bead holder assembly  10  may then be moved away from the bead setter.  
         [0026]    While a certain representative embodiment and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention.  
         [0027]    Having thus described the invention, it is now claimed: