Abstract:
A carbon fiber tubular pole and method of construction thereof. The pole includes a left in place lightweight mandrel, preferably formed of tubular polyvinylchloride or cardboard, which substantially reduces cost of manufacture. Moreover, an outer tubular glass fiber sleeve over a tubular carbon fiber sleeve resin saturated through and through maintains the aesthetic appearance of the black carbon fiber while substantially strengthening the end product. A second outer layer of a mixture of resin and colloidal silica over the cured resin layer adds shine and increases smoothness.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to the construction and manufacture of tubular pole members having a distinctive appearance of black carbon fiber, and more particularly to such a pole or contoured support member and method of forming same at a substantially reduced cost of manufacture. 
     2. Description of Related Art 
     Tubular poles and structural contoured members formed of sleeve carbon fiber are well known. The enhanced strength and overall appearance of the black carbon fiber material greatly enhances the strength and aesthetic value despite the greatly exaggerated cost of manufacturing such a product in lieu of similar conventional tubular aluminum product. However, the well-known method for manufacturing such a carbon fiber pole which may typically only be made in a shorter, straight configuration in the carbon fiber industry is through the use of high-tech procedures such as autoclaving and microfilament machines which enable the removal of a mandrel prior to the complete curing of resin saturated into the carbon fiber material. Moreover, when manufacturing smaller diameter carbon fiber tubular members having a diameter of less than 1″, removal of the support mandrel becomes exceedingly difficult. 
     Further, because the cured carbon fiber tubular structure cannot be formed to produce a curve such as for a bow support for a bimini top of a boat, there are no such carbon fiber products in the marketplace at this time. 
     The present invention provides both a structure and a method for producing both straight tubular and curved tubular support members formed of carbon fiber to provide the strength and distinctive appearance of the black sleeve while substantially reducing the cost of manufacture by simply leaving a sacrificial tubular mandrel in place within the end product structure. A mandrel is any tube made of a synthetic or fibrous material that has the properties of being round, hollow and lightweight. Examples of a synthetic pole may be PVC tubing, plastic tubing or fiberglass tubing. Such a mandrel is preferably in the form of either a light-weight tubular polyvinylchloride (PVC) tubing or cardboard tubing which are left in place and cured and become a monolithic part of the entire structure. 
     The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those skilled in the art upon a reading of the specification and a study of the drawings. 
     BRIEF SUMMARY OF THE INVENTION 
     This disclosure is directed to a carbon fiber tubular pole and curved tubular structural member and method of construction thereof. The end product includes a left-in-place lightweight mandrel, preferably formed of tubular synthetic or fibrous, which substantially reduces cost of manufacture. Moreover, an outer tubular layer of glass fiber over a tubular carbon fiber layer and cured resin saturated through and through fiber layers maintains the aesthetic appearance of the black carbon fiber while substantially strengthening the end product. 
     It is therefore an object of this invention to provide carbon fiber tubular poles and curved support members which have the outward aesthetic appearance of flat black carbon fiber sleeve. 
     Still another object of this invention is to provide a carbon fiber tubular structure formed leaving an inner tubular mandrel in place within the structure as a manufacturing support to substantially reduce manufacturing costs. 
     Yet another object of this invention is to provide a carbon fiber tubular structure which is formed over a precontoured or curved tubular mandrel so as to overcome the limitation that tubular carbon fiber poles currently prohibit the contouring of cured carbon fiber pole stock after the resin has been hardened and cured. 
     Yet another object of this invention is to provide a method of forming tubular carbon fiber members utilizing slow rotation of the member as the resin is applied to fully saturate the carbon fiber and glass fiber layers all of the way to the tubular mandrel which insures a monolithic-like structure when cured. 
     The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative and not limiting in scope. In various embodiments one or more of the above-described problems have been reduced or eliminated while other embodiments are directed to other improvements. In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following descriptions. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1  is a side perspective of one end product produced by the methodology of the disclosure. 
         FIG. 2  is a side perspective view of another end product produced by the methodology of the disclosure. 
         FIGS. 3 to 15  are side perspective views showing the preferred steps in implementing the method of this disclosure to produce one embodiment of an end pole product of this disclosure. 
         FIG. 16  is a side perspective view showing inserting an alternate support tube within the tubular mandrel for temporarily supporting larger diameter poles during manufacture. 
         FIG. 17  shows an optional step in the resin curing process for the tubular pole produced in  FIG. 16  within the scope of this disclosure. 
         FIGS. 18 and 19  show an optional and preferred step of applying a resin/silica coating over the cured resin and hanging the end product vertically for curing. 
         FIG. 20  is a perspective view of a finished tubular carbon fiber pole. 
         FIG. 21  is a section view in the direction of arrows  21 - 21  in  FIG. 20 . 
         FIG. 21A  is an enlarged view of a segment of pole section in  FIG. 21 . 
         FIG. 21B  is an alternate and preferred embodiment of the pole section shown in  FIG. 21 . 
         FIG. 22  shows three perspective views of two alternate embodiments of a bimini top support bow or member as well as an exploded view of the second embodiment thereof. 
     
    
    
     Exemplary embodiments are illustrated in reference figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered to be illustrative rather than limiting. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Nomenclature 
     
         
           10 . boat pole assembly 
           12 . pole assembly 
           14 . pole 
           16 . boat hook 
           18 . finishing end cap 
           20 . bimini brace assembly 
           22 . brace assembly 
           24 . brace 
           26 . end pivot fitting 
           28 . mid-pivot bracket 
           30 . PVC mandrel 
           32 . support rod 
           34 . mandrel outer surface 
           36 . driving notch 
           38 . carbon fiber sleeve 
           40 . glass fiber sleeve 
           42 . uncured resin 
           42 ′. cured resin 
           44 . uncured resin/silica 
           44 ′. cured resin/silica 
           46 . pole assembly 
           48 . large pole 
           50 . PVC mandrel 
           52 . carbon fiber sleeve 
           54 . glass fiber mat 
           56 . cured resin 
           58 . cured resin/silica 
           60 . PVC bimini mandrel 
           62 . bow segment 
           64 . corner segment 
           66 . upright leg 
           70 . segmented PVC bimini mandrel 
           72 . bow segment 
           74 . upright leg 
           76 . corner segment 
           78 . connector tube 
       
    
     Referring now to the drawings, and firstly to  FIGS. 1 and 2 , two finished products produced by the methodology of the present disclosure are there shown generally at numerals  10  and  20 . In  FIG. 1 , the boat pole assembly  10  is formed of an elongated pole assembly  12  which includes a tubular carbon fiber pole  14  having a finishing end cap  18  which lockingly receives a boat hook  16  held therewithin, the shaft of which extends partway into the tubular pole  14 . The finished appearance shown as being transparent is that of a longitudinally stranded carbon fiber linear sleeve therebeneath. In  FIG. 2 , a bimini brace is shown at  20  and also includes an elongated carbon fiber brace assembly  22  formed of an elongated tubular carbon fiber pole  24 . The bimini brace  20 , being shown as a product example, also includes an end fitting  26  and a mid-span pivot bracket  28  lockingly positioned and functioning in a conventional manner. 
     Referring now to  FIGS. 3 to 15 , the methodology of this disclosure producing the product shown typically shown in  FIGS. 1 and 2 , is there shown. In  FIG. 3 , an elongated removable support rod  32 , preferably formed of aluminum or copper, is inserted into a length of polyvinylchloride (PVC) mandrel  30 , the PVC mandrel  30  forming a permanent part of each end product. The support rod  32  is slid into the hollow interior of the mandrel  30  in the direction of arrow A. Thereafter, the outer surface  34  of the mandrel  30 , supported by the support rod  32 , is sanded and roughened so as to better adhere to resin applied thereover in a later step. 
     As seen in  FIG. 5 , driving notches  36  are formed into one end of the mandrel  30  after which a plug guide is slid part way into that same end of the mandrel  30  in the direction of arrow B. The rounded distal end of the plug guide is left exposed so that, as seen in  FIG. 7 , a length of tubular carbon fiber sleeve  38  may be easily slidingly engaged onto the outer surface of the mandrel  30  in the direction of arrow C. 
     Once this carbon fiber sleeve  38  is fully in place over the mandrel  30  as shown in  FIG. 8 , the carbon fiber sleeve  38  is manually stretched as arrow D in the direction of arrows E in  FIG. 9  so as to more tightly conform against the exterior surface of the mandrel  30 . Thereafter, as seen in  FIG. 10 , a length of tubular glass fiber sleeve  40  is slid over the top of the carbon fiber sleeve  38  in the direction of arrow F. Once the glass fiber sleeve  40  is in position over the previously stretched and tensioned carbon fiber sleeve  38 , the glass fiber sleeve  40  is also stretched in the direction of arrows G and tensioned in the direction of arrows H by manual manipulation thereof to insure outstretched and tightened position of the glass fiber sleeve  40 . This manipulation is similar to the collapsing and tightening of “Chinese handcuffs”. 
     The preferred carbon fiber sleeve is formed of either tubular biaxial or unidirectional carbon fiber material. The preferred glass fiber sleeve is roving biaxial sleeving. 
     This entire arrangement shown in  FIG. 12  is then positioned onto a rotary apparatus by sliding the driving notch  36  into engagement on driving pin of the drive shaft of the rotary, after which the support shaft is moved into the opposite end of the mandrel  30  in the direction of arrow J. 
     The rotary is then activated to slowly (about 1 to 5 RPM) rotate the mandrel  30  in the direction of arrow L simultaneously with brush application of uncured resin  42  applied over all of the exterior surface of the glass fiber sleeve  40 . The resin  42  may be vinyl or polyester epoxy and of sufficiently low viscosity so as to fully penetrate through both the glass fiber sleeve  40  and the carbon fiber sleeve  38  to fully saturate those layers down to the outer surface of the mandrel  30 . As seen in  FIG. 15 , thereafter a user wearing protective vinyl or latex gloves then smoothes the entire arrangement of resin  42 , glass fiber and carbon fiber sleeves  38  and  40  by movement manually in the direction of arrows M while squeezing. The preferred resin is a low viscosity epoxy using a non-flushing hardener, slow, medium, or fast curing depending upon ambient temperature. 
     For smaller diameter products, curing of the resin may take place while being held with or without rotation within the rotary shown in  FIG. 15 . However, where the diameter of the end product exceeds about 1″, it is preferred that a support tube be inserted into the mandrel  30  as shown in  FIG. 16 . The mandrel  30 , being non-porous with respect to uncured resin  42 , will prevent any resin  42  from contacting the outer surface of the support tube, eliminating any risk that the support tube may not be easily removed after the resin  42  applied to the outer surface shown in  FIGS. 14 and 15  has cured. 
     Once this support tube is inserted in the direction of arrow N as seen in  FIG. 16 , the ends of the support tube may be held horizontally or, as seen in  FIG. 17 , for larger diameter end product, the support tube may be attached to and hung vertically by a hanger at an upper end and, to prevent the mandrel  30  from sliding downwardly, a stop pin may be inserted through the opposite end of the support tube. The work product is being held vertically so as to insure a perfectly straight pole end product and without the risk of the resin running which is insured by the careful, even distribution of all uncured resin in the step shown in  FIG. 15 . 
     In  FIG. 18 , after the resin  42  has been cured and hardened, it is preferred that an outer layer of resin in combination with a small quantity of colloidal silica at  44  be brush applied while rotating the work product. Alternately, the entire arrangement is then removed from the rotary into an upright orientation shown in  FIG. 19  wherein the hanger is attached to an overhead support after a stop pin has been positioned through a transverse aperture through the support tube at the opposite end thereof. The colloidal silica/resin outer coat  44 ′ provides a more serviceable and smoother surface. 
     Referring now to  FIGS. 20 ,  21  and  21 A, a segment of a length of carbon fiber pole is there shown at  46 . Again, the finished carbon fiber  48  has a translucent or transparent visual effect through the cured resin  56  and the outer glass fiber sleeve  54  so that the black carbon fiber sleeve  52  is visible through these combined layers of resin and glass fiber sleeve. As seen in  FIG. 21B , the preferred embodiment also includes the outer layer of cured resin with colloidal silica  58  which is applied manually over the cured surface of the resin  56  as previously described. 
     Referring now to  FIG. 22 , the tubular mandrel aspect of the present invention is applied to curved tubular structural members such as the support bow of a bimini top of a sailboat or power boat. In one embodiment  60 , the PVC mandrel  62  is heated and formed at  64  so as to provide straight upright legs  66  and a large radius curved center portion  62  configured as aesthetically dictated for the bimini canvas. Alternately, the PVC mandrel may be formed in segmented portions at  70  wherein the center portion  72  is first heated and formed around a suitable form or manually and then interconnected to tightly bent corners  76  by connectors  78  for attachment to elongated upright tubular portions  74  to form the same desired configuration as with respect to the mandrel  60 . 
     It is again stressed that the important aspect of this invention is that the inner mandrel becomes a permanent part of each hollow carbon fiber pole or contoured product. The resin is saturated through the outer layer of glass fiber and through the inner layer of carbon fiber sleeve to reach and become a monolithic part with the inner tubular mandrel which again may be formed of polyvinylchloride material, cardboard material or any other suitable material which affords a lightweight tubular inner form over which the carbon fiber sleeve, the glass fiber sleeve, and the resin are applied. 
     While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations and additions and subcombinations thereof. It is therefore intended that the following appended claims and claims hereinafter introduced are interpreted to include all such modifications, permutations, additions and subcombinations that are within their true spirit and scope.