Patent Publication Number: US-6209556-B1

Title: Umbrella skeleton made of composite material

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to an umbrella skeleton, and more particularly to an umbrella skeleton which is made of a composite material. 
     BACKGROUND OF THE INVENTION 
     The conventional umbrella is generally composed of a shade of cloth, which is stretched over a foldable radial frame supported by a shaft of a metal material. The metal shaft is conductive to electricity and is thus prone to produce static electricity at the time when the umbrella is used in the rainy day. The user of the conventional umbrella is therefore vulnerable to electric shock. In addition, the metal shaft gives an added weight to the umbrella and rusts easily. 
     SUMMARY OF THE INVENTION 
     It is the primary objective of the present invention to provide an umbrella skeleton which is made of a composite material to prevent the user of the umbrella from being subjected to static electric shock. 
     It is another objective of the present invention to provide an umbrella skeleton which is made of a composite material and is relatively light in weight. 
     It is still another objective of the present invention to provide an umbrella skeleton which is made of a composite material to give a user thereof a better grip sense. 
     The objective, features and functions of the present invention will be readily understood upon a thoughtful deliberation of the following detailed description of the present invention with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a schematic view of a first preferred embodiment of the present invention. 
     FIG. 2 shows a sectional view taken along the direction indicated by a line  2 — 2  as shown in FIG.  1 . 
     FIG. 3 shows a sectional view of a second preferred embodiment of the present invention. 
     FIG. 4 shows a schematic view of a third preferred embodiment of the present invention. 
     FIG. 5 shows a front schematic view of a shaft of a fourth preferred embodiment of the present invention. 
     FIG. 6 shows a front schematic view of a shaft of a fifth preferred embodiment of the present invention. 
     FIG. 7 shows a front schematic view of a shaft of a sixth preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in FIG. 1, an umbrella skeleton  10  embodied in the present invention is composed of component parts which are described hereinafter. 
     A shaft  20  is of a slender and hollow construction. 
     A predetermined number of ribs  30  are arranged radially from the shaft  20  such that inner ends of the ribs  30  are fastened pivotally with the top of the shaft  20 , and that the ribs  30  can swivel on the pivoting portion serving as a fulcrum. 
     A predetermined number of strut ribs  35  are equal in number to the ribs  30  and are fastened pivotally at one end thereof with the ribs  30  such that other end of the strut ribs  30  is fastened pivotally with a runner  40 . 
     The runner  40  is slidably fitted over the shaft  20  such that the runner  40  can be displaced and located between an upper stop point and a lower stop point. The runner  40  can be displaced manually or automatically. The runner  40  is not the subject matter of the present invention. 
     The shaft  20  is composed of a fiber-reinforced plastic core  22  and a wooden sheath  24  covering the core  22 , as shown in FIG.  2 . The fiber-reinforced plastic core  22  is made of a plurality of carbon fiber fabric sheets which are preimpregnated with epoxy resin and wound together. The wooden sheath  24  is made of a thin wooden skin, a thin bamboo skin, or a wooden film. 
     As shown in FIG. 3, the shaft  20  is provided with a protective layer  26  covering the wooden sheath  24 . The protective layer  26  is made of a thin transparent fiber cloth, such as a glass fiber cloth or a nonwoven cloth. 
     As shown in FIG. 4, the second preferred embodiment of the present invention is different from the first preferred embodiment of the present invention in that the former has a segmented shaft  50  consisting of a first segment  52  and a second segment  54 . The first segment  52  can be extracted from and retracted into the second segment  54 . 
     As shown in FIG. 5, a shaft  60  of the third preferred embodiment of the present invention is composed of a core (not shown in the drawing), and a wooden sheath  62 . The shaft  60  has a grip end  64  which is not covered by the wooden sheath  62 . 
     As shown in FIG. 6, a shaft  70  of the fourth preferred embodiment of the present invention is composed of a core  72  having a midsegment which is covered with a wooden sheath  74 . With the exception of the midsegment of the core  72 , other portions of the core  72  are not covered with the wooden sheath  74 . 
     As shown in FIG. 7, a shaft  80  of the fifth preferred embodiment of the present invention is composed of a fiber-reinforced plastic core  82  and a plurality of wooden sheath segments  84 ,  86 , and  88 , which are arranged at an interval. 
     All shafts embodied in the present invention may be provided with a protective layer covering the wooden sheath. The protective layer is made of a thin transparent fiber cloth, such as a glass fiber cloth or a nonwoven cloth. 
     The present invention has the advantages, which are described hereinafter. 
     The shaft of the umbrella skeleton of the present invention is provided in the outermost layer with a wooden sheath which is nonconductive to electricity to prevent the user of the umbrella from being subjected to electrical shock in the rainy weather. 
     The shaft of the umbrella skeleton of the present invention is made of materials resistant to rust and rust corrosion. In addition, the shaft of the present invention is made of the composite material and is therefore provided with a better structural strength. The wooden sheath of the shaft of the present invention gives an added esthetic effect to the shaft. 
     The shaft of the composite material is relatively lighter in weight to result in a reduction in overall weight of the umbrella.