You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION  
       [0001]     This invention relates to wallboard comer bead and particularly to a wallboard corner bead employing a reinforcing member.  
       BACKGROUND OF THE INVENTION  
       [0002]     Wallboard corner beads which are suitable for use on inside or outside corners are known. However, prior art beads are insufficient in that they do not provide enough protection from being damaged by objects that strike them when they are installed. This is a common, even frequent, occurrence when the corner bead is installed on an exterior surface where it is likely to be struck by servicemen using dollies and other equipment, children and their toys, or careless walkers-by. Moreover, in arch applications, it is common to get flat spots in the arch due the irregular nature of prior art arch beads. Therefore, there is a need in the art for a corner bead having improved strength and resiliency.  
       SUMMARY OF THE INVENTION  
       [0003]     The present invention comprises a corner bead for joining adjacent pieces of wallboard comprising an arched center section having a pair of wing sections attached thereto. The arched center section extends outwardly above planes defined by the wing sections, and the wings and arched center section define an interior surface which is placed adjacent the wallboard and an exterior surface which is placed opposite the wallboard. A reinforcing member is disposed adjacent the interior surface of the arched center section and attached thereto to provide rigidity to the arched center section. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0004]     In the accompanying drawings which form part of the specification and wherein like numbers and letters refer to like parts wherever they occur  
         [0005]      FIG. 1 a  sectional view of a corner bead according to one embodiment of the present invention;  
         [0006]      FIG. 2 a  sectional view of a corner bead applied to an intersection of wallboard according to one embodiment of the present invention;  
         [0007]      FIG. 3 a  sectional view of a corner bead according to another embodiment of the present invention;  
         [0008]      FIG. 4  is a side view of a comer bead according to yet another embodiment of the present invention;  
         [0009]      FIG. 5  is a fragmentary perspective view of the corner bead of  FIG. 3  applied to an arched opening;  
         [0010]      FIG. 6  is a fragmentary perspective view of the corner bead of  FIG. 3  applied to a rounded wall; and  
         [0011]      FIG. 7  is a fragmentary enlarged perspective view of the corner bead of  FIG. 3  applied to a curved corner joint.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0012]     The preferred form of the invention is shown in  FIGS. 1 and 2  and comprises a preformed corner bead  10  for covering an exterior corner where two pieces of wallboard A meet. The corner bead  10  is made from polyvinyl chloride or composite material and is about 0.035″ thick. The corner bead comprises an arched center section  11  connecting outwardly extending wings  14  and  15 . The wings  14  and  15  are most commonly positioned at a generally 90 degree angle with respect to one another, although other angles can be employed. The top of the arch section  11  preferably is about 1/16″ to about 3/32″ above the planes defined by the wings  14  and  15 .  
         [0013]     A reinforcing member  16  is provided in the general area of a pocket  18  formed by the arched center section  11 . The reinforcing member  16  is preferably a tempered wire placed in a bed of adhesive or hot melt glue or thermoplastic  17  in the arched center section  11  and maintained in placed with an adhesive. The reinforcing member  16  can be applied by either applying a first coat of adhesive  17  to the pocket  18 , inserting the reinforcing member  16  and covering the wire with a second coat of adhesive  17  over the top of reinforcing member or merely applying the adhesive  17  to the pocket  18  and embedding the reinforcing member  16  in the adhesive  17 . The corner bead  10  is applied to a wall in the same manner as corner bead of the prior art. Specifically, a coating  20  of drywall compound is applied to the wallboard A to provide adhesion between the corner bead  10  and the comer is applied to the wallboard A. Next, skim coat  22  of drywall compound is applied over the corner bead  10  and the corner bead is feathered into the wallboard with a coating  24  as a single process. Sanding and finish coats of drywall compound provide a smooth surface. Once the corner bead  10  is applied to the wallboard A, the tempered wire  16  provides rigidity, strength and resiliency. It will also form an even and consistent arch without flat spots.  
         [0014]     Alternatively, the reinforcing member  16  may comprise a polyamide hot melt glue as shown in  FIG. 3 , the hot melt glue provides a lesser degree of strength of rigidity, but still represents an improvement over the prior art. The hot melt glue is applied to the pocket  18  of the arched center section in a heated, liquid state and fills the pocket  18 . The glue then cools to a solid state and provides a reinforcing function.  
         [0015]     Preferably, though not required, adhered to the corner bead are a plurality of discrete fibers, as described in detail in U.S. Pat. No. 5,418,027, which is hereby incorporated by reference. The fibers are known as floc and can be Nylon, rayon, Dacron, polyester, cotton or other cellulose, or other similar fibers or combinations of fibers. The fibers have a diameter of about 1-3 Tow deniers, but larger or smaller sizes will work. The preferred lengths of fibers are about 0.005 to about 0.030 inches. Those parameters are preferred because when the coated corner bead is applied to a wall joint and only the corner bead edge is skim coated, the uncoated surfaces can be painted as a finished wall. The preferred size fibers are small enough to lay down when painted so the paint will create a smooth finished surface. Larger sized fibers do not give the desired smooth, painted surface.  
         [0016]     The previously described embodiment is used when the wallboard meets along a generally straight line. However, where archways are employed or other nonlinear junctions of wallboard of  FIG. 1  is modified as shown in  FIG. 3 . The second embodiment comprises a curvable corner bead  10  having the outwardly depending and diverging wings  14  and  15  attached by the arched center section  11 . The wings  14  and  15  are provided with V-shaped notches  32  which have their apex  34  offset from the arched center section  11  and their widest part is most remote from the center arched section  11 . The notches  32  thus define adjacent triangular solid members  14   a  and  15   a  on their respective wings  14  and  15 .  
         [0017]     The notches  32  in each depending wing  14  and  15  are staggered so that the apex of a notch  32  on wing  14  is aligned with approximately the center of the triangularly shaped solid member  15   a  of the opposed wing  15 . Thus the wings  14  and  15  are formed of a continuous series of triangularly shaped pieces  14   a,    15   a.  At the point on the triangular pieces  14   a,    15   a  which is most remote from the center section  11  and along the outer edges of the corner bead  10  are releasable and removable tear strips  36  and  38 . The purpose for the tear strips  36  and  38  is to allow the notches  32  to separate when the comer bead  10  is applied to an arched or rounded opening or comer as shown in  FIGS. 7-9 . The pieces  15   a  on the inner side of the curved comer gather together as also seen in  FIG. 9 . Such an arrangement is disclosed in U.S. Pat. Nos. 5,4.18,027 and 5,037,686, which are hereby incorporated by reference.  
         [0018]     Just as in the first embodiment, a reinforcing member  16  comprising tempered wire is placed in the arched center section  11  and maintained in placed with an adhesive that encapsulates the wire. Alternatively, the reinforcing member  16  may comprise a polyamide hot melt glue as in the first embodiment.  
         [0019]     This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

Summary:
A corner bead for joining adjacent pieces of wallboard including an arched center section having a pair of wing sections attached thereto. The arched center section extends outwardly above planes defined by the wing sections, and the wings and arched center section define an interior surface which is placed adjacent the wallboard and an exterior surface which is placed opposite the wallboard. A reinforcing member is disposed adjacent the interior surface of the arched center section and attached thereto to provide rigidity to the arched center section.