Abstract:
A surfboard, comprising a blank made of lightweight, semi-rigid material and having a top major surface. A layer of resin-impregnated cloth adhered to the top major surface and a leash plug including a cup portion that is set into the top major surface of the blank and at least one extension that is interposed between the blank and the layer of resin-impregnated cloth.

Description:
BACKGROUND OF THE INVENTION 
     The present invention has to do with a surfboard having a leash plug that is a more thoroughly anchored band than the leash plug of any presently available surfboard and method of manufacturing the same. The leash plug of a surfboard retains the surfboard leash. This is a line of extruded polyurethane bearing a loop of woven material on its distal end for a surfer to retain about his ankle. When the surfer is thrown off his surfboard, the leash retains the surfboard. This is an important function because a surfboard typically costs $450 or more. Even more important, however, is the prevention of accidents that a loose surfboard could cause to the surfer (who owns the board), as well as other people in the general area. More specifically, a loose surfboard has the potential to seriously injure or kill a surfer or a swimmer. 
     Today, a surfboard is manufactured by starting with a blank made of lightweight polystyrene (STYROFOAM™ being the most familiar trademark for this type of material) or polyurethane that is in the general shape of a surfboard and then adding many layers of resin-impregnated fiberglass cloth around it. This procedure is known as “glassing” the board. After the board is glassed, additional layers of resin may be added to strengthen the board. In the next phase, a small hole is punched through the layers of resin-impregnated fiberglass cloth and into the blank. Resin is poured into this hole and a leash plug is inserted into the resin-filled hole. 
     After the leash plug has been correctly positioned, the board manufacturing operation must be temporarily halted while the resin sets. Any interruption in the manufacturing process is costly because it forces the manufacturer to give up a portion of his manufacturing space to accommodate the partially manufactured board. Alternatively, the manufacturer may stow the partially manufactured board and retrieve it after the resin has set. Although this second option does not waste manufacturing space, it does require a place to stow the partially assembled boards and the additional labor to do so. 
     Additionally, leash plugs installed according to this method have some vulnerability to being pulled out by a particularly strong wave. The importance of avoiding the resultant loosing of a surfboard have been noted above. 
     To lessen the likelihood that the leash plug will be pulled out, many large surfboards sport two leash plugs. This, of course, increases the cost of manufacturing the surfboard. Moreover, it is generally more convenient to the surfer to have the leash installed in a single place on the surfboard. 
     SUMMARY 
     In a first separate, the present invention is a surfboard, comprising a blank made of lightweight, semi-rigid material and having a top major surface and a layer of resin-impregnated cloth adhered to the top major surface. In addition, a leash plug includes a cup portion and an extension and is set into the blank so that the extension is interposed between the blank and the layer of resin-impregnated cloth. 
     In a second separate aspect, the present invention is a method of manufacturing a surfboard, that begins with providing a blank of lightweight semi-rigid material having a top major surface and then forming an indentation in the blank at the top major surface. Further, a leash plug is provided having a cup portion and an extension that extends outwardly from the cup portion. Next, the cup portion is placed in the indentation so that the extension extends outwardly from the cup over a portion of the top major surface. A cloth is placed over the top major surface, so that the extension is interposed between the top major surface and the cloth. At some point the cloth is impregnated with resin and the resin is cured. 
     In a third separate aspect, the present invention is a leash plug having a top and a bottom and comprising a cup portion, traversed by a cross-bar. In addition, a rim extends outwardly from the cup portion and a retention wall extends downwardly, substantially at a right angle to the rim. 
     The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of the preferred embodiment(s), taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a partial perspective view of a surfboard according to the present invention; 
     FIG. 2 is a perspective view of a leash plug according to the present invention; 
     FIG. 3 is a top sectional view of the surfboard of FIG.  1 . 
     FIG. 4 is a partial cross-sectional view of the surfboard of FIG. 1 taken along line  4 — 4  of FIG.  3 . 
     FIG. 5 is a partial cross-sectional view of the surfboard of FIG. 1 taken along line  5 — 5  of FIG.  3 . 
     FIG. 6 is a partial cross-section taken along line  4 — 4  of FIG. 3 of a manufacturing step in the production of the surfboard of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, a preferred embodiment of a surfboard  10  according to the present invention is built using a leash plug  12 , for retaining a leash  13 . Leash plug  12  includes a cup portion  14  encircled at its top by an annular ridge  15  and an extension or rim  16  extending outwardly from rim  16 ; a wall  18  depending downwardly from the rim  16 ; and a cross-bar  20 , crossing the top of the cup portion  14  and providing an attachment point for the surfboard leash  13 . Additionally, a lip  22  extends downwardly from the exterior of cup portion  14 . 
     Referring to FIGS. 1-5, a surfboard according to the present invention is constructed by providing a blank  24  made of lightweight cellular polystyrene (STYROFOAM™ being the most familiar trademark for this type of material, as noted earlier) or polyurethane. A shallow depression, typically shaped to accommodate the cup portion  14  and rim  16  of leash plug  12 , is formed (typically by a router) in the place where the leash plug  12  is slated to be positioned. A tape is placed over the opening of cup portion  14  to prevent it from receiving resin during the glassing operation described below and acetone is used to wipe any mold release agent or other coating from plug  12 . Then leash plug  12  is pushed into this depression and is anchored in place by the wall  18  and the lip  22 , which are coated with resin and cut into the polystyrene material of the blank  24 . In one preferred method, some resin is brushed onto the bottom of the plug  12  prior to pushing the plug  12  into the depression. This is meant to help retain the plug  12  during manufacturing and to add strength to the plug-to-blank bond. 
     Next, the board is “glassed.” Glassing entails the addition of a pair of resin-impregnated layers of fiberglass cloth  26  and  28  onto blank  24 . FIG. 6 shows a cross-sectional view of the leash plug  12  retained in the surfboard  10  immediately after the glassing operation. In some instances a further coat of resin is applied after glassing is completed. 
     Next, the surfboard is sanded. Referring to FIGS. 4 and 5, the sanding operation uncovers the cup portion of  14  of leash plug  12  while leaving the rim  16  covered by layers of resin-impregnated fabric  26  and  28 . Moreover, layers  26  and  28  have been sanded flush with the top of ridge  15  so that no side surface of layer  26  or  28  is left to unravel or be exposed to the wearing effects of the seawater. At the completion of the sanding operation, leash plug  12  is positively retained in place by layers of cured, resin-impregnated fiberglass cloth  26  and  28  that have been placed over the rim  16  of leash plug  12 . 
     The advantages of this method of manufacturing and the resultant surfboard should now be readily apparent. There is no need to halt the manufacturing process to wait for a globule of resin to dry after leash plug  12  has been inserted. This is because there is no reliance solely on such a globule of resin to retain the leash plug. Rather, the leash plug is far more firmly and positively retained by the resin-impregnated cloth  26  and  28 , thereby forming an integral and tough part of the surfboard  10 . This construction is extremely unlikely to permit plug  12  to come loose, even under the strongest tension from the leash. Therefore, this method of manufacturing is much more efficient than current methods and the resultant surfboard contains a more securely anchored leash plug. 
     In a further preferred embodiment, extension  16  is broken up into an extension (smaller than portion  16 ) and other additional extensions. The phrase, “an extension,” may be used to describe one of the extensions of this embodiment and should not be taken to negative the possible existence of additional extensions. The same principal is true for all of the other elements described in this disclosure. 
     In one preferred embodiment, the rim  16  is 4.1 cm (1.61 in) long and 3 cm (1.19 in) wide. The interior dimensions of the cup portion  14  are 1.83 cm (0.72 in) long and 0.757 cm (0.298 in) wide. Moreover, the leash plug  12  is 1.5 cm (0.593 in) high, of which 1.12 cm (0.443 in) represents the extent of beneath the rim  16  of wall  18  and cup portion  14  including lip. The greater portion of leash plug  12  is molded out of a mixture of 80% nylon and 20% glass fibers. Cross-bar  20  is made of metal, most typically stainless steel that has been fit through a pair of accommodating holes on either side of cup portion  16 . A leash  13  may be attached to cross-bar  20  by means of a clip. 
     The terms and expressions which have been employed in the foregoing specification are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.