Patent Publication Number: US-6710243-B2

Title: Structure of signal line

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to a structure of signal line, and especially to a structure of signal line with high strength that renders the line itself not to deform when being bent; it is suitable particularly for use in signal transmission lines such as those for horns, power lines or the like. 
     2. Description of the Prior Art 
     In a conventional signal line such as that shown in FIG. 1, conductors “A” are enveloped in a PVC (or PE) insulation layer “B” to be entangled with another conductor enveloped in the PVC (or PE) insulation layer “B”, then a filler layer “C” is used to envelop the insulation layer “B”. The filler layer “C” is added thereover with a knitted metallic obscuring layer “D” which is further enveloped completely in a PVC (or PE) coating layer “E”. The gap in such an improved electric line are totally filled by the filler layer “C” which envelops the PVC (or PE) insulation layer “B” therein, this can reduce transient pulsing, and can reduce the danger of melting of the PVC (or PE) insulation layer “B” when loading is increased. Although such a structure can get improvement on the defect of having a gap of the conventional signal line, it still can not completely get rid of the main defect of mutual interference induced during transmission by contact of the two conductors thereof too close to each other. 
     Referring to FIG. 2 showing another conventional structure of signal line, the signal line is made a tube body  1  from a PVC insulation layer, the inner wall of the tube body  1  is provided with two hollow thin pipes  2  with a space  4  therebetween, the two hollow thin pipes  2  are both extended therein a rectangular conductor  3  for effectively getting rid of the defect of mutual interference induced by being too close to each other of the two conductors  3 . However, by virtue that there are only two hollow thin pipes  2  in the tube body  1 , and the rest space  4  is empty, the strength of the tube body  1  is not enough, the space  4  (distance) between the two conductors  3  may change by bending, thereby the two conductors  3  not only mutually interfere with each other again, but also signal transmission may be influenced by deformation of the two conductors  3  induced by pressing on the weak hollow tube body  1 . In this view, the conventional structure of signal line is not ideal either. 
     Therefore, the motive in study and development of the present invention is to improve on the defects resided in the conventional structures of signal line, in order to provide 100% obscuring, to minimize the degree of mutual interference, to increase the strength of the signal line to avoid deformation of the structure of the signal line due to bending. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to increase the strength of a signal line to avoid deformation of the structure of the signal line due to bending. 
     The secondary object of the present invention is to minimize the degree of mutual interference and thereby to provide a signal line with 100% obscuring, 
     To achieve the above stated objects, the present invention is comprised of a core portion, a middle filler layer, an obscuring layer and an outer coating portion. The core portion has at least a rectangular conductor which is enveloped by an insulation tape; the obscuring layer has at least a knitted metallic obscuring layer; the outer coating portion has at least a layer made of polyvinyl chloride composition; and the middle filler layer is comprised of a plurality of hollow tubes. The core portion is tangled with the middle filler layer to make the line stronger in addition to being flexible, so that the line will not have the core portion damaged when it is bent to deform, plus the obscuring function of the obscuring layer, the degree of mutual interference can be reduced to the minimum. 
     The present invention will be apparent after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an analytic perspective view showing the structure of a conventional signal line; 
     FIG. 2 is a perspective view showing the appearance of another conventional signal line; 
     FIG. 3 is an analytical perspective view showing the structure of an embodiment of the present invention; 
     FIG. 4 is an enlarged schematic perspective view of the core portion of the present invention; 
     FIG. 5 is a cross-sectional view of the embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring firstly to FIG. 3, the present invention is comprised of a core portion  10 , a middle filler layer  20 , an obscuring layer  25  and a coating portion  30 . The core portion  10  is a conductor made of pure copper of single crystal in single direction, in a rectangular shape, and is wrapped up in a wrapping roll made from foamed Teflon (PTFE) tape. The preferred embodiment uses a twin layer wrapping roll including an inner layer  11  and an outer layer  12 , and then uses an outermost metallic tape for wrapping up, such as is shown in FIG.  4 . Further, the cross section of the positive pole in the core portion  10  is smaller than that of the negative pole. The middle filler layer  20  is made from a plurality of hollow tubes, one of the hollow tubes is a larger volume hollow tube  21 , an outer metallic wrapping roll  22  envelops the hollow tubes, and the obscuring layer  25  envelops the metallic wrapping roll  22 , the obscuring layer  25  is a knitted metallic net. The coating portion  30  is made of polyvinyl chloride (PVC) composition and is divided into a first coating layer  31  and a second coating layer  32 . 
     The larger volume hollow tube  21  of the middle filler layer  20  and the small hollow tubes are placed in the core portion  10 , and are twisted in an identical direction (clockwise or counterclockwise), then the outer metallic wrapping roll  22  is used to envelop the middle filler layer  20  and the core portion  10 , these are enveloped by the knitted metallic net-like obscuring layer  25 , and finally, the first coating layer  31  and the second coating layer  32  of the coating portion  30  are used to sequentially envelop the knitted metallic net-like obscuring layer  25  to complete the structure of the present invention. 
     The conductor made of pure copper of single crystal in single direction can be coated with lacquer to prevent the conductor from oxidation. And more, the dielectric coefficient of the Teflon in the inner layer  11  and the outer layer  12  made from foamed Teflon (PTFE) tapes is largest, hence these layers  11 ,  12  get an excellent insulation effect, and the degree of mutual interference can be reduced to the minimum; plus the 100% obscuring effect provided by the multi-layer obscuring of the outer metallic wrapping roll  22 , the knitted metallic net-like obscuring layer  25 , the large volume hollow tube  21  and the middle filler layer  20  etc., the interference among a magnetic field, radio frequencies and static electricity can be effectively reduced, thereby, attenuation rate of the line can be reduced, distortion of the line can be smaller, and high quality of the line can be obtained. Moreover, the cross section of the positive pole in the core portion  10  is smaller than that of the negative pole; therefore, when a loop is formed, signals transmitted under a fast speed from the positive pole core component with a smaller cross-sectional area to the negative pole core component will not be jammed to influence the quality of transmission. 
     And more, the middle filler layer  20  and the core portion  10  are twisted in an identical direction, so that in any section of the signal line, as shown in FIG. 4, the core components of the core portion  10  can be kept parallel to each other without mutual interference; and the core portion  10  is entangled with the middle filler layer  20 , this reinforces the signal line and increases the flexibility of the signal line, so that the signal line will not deform during bending to damage the core portion  10 . 
     Accordingly, the structure of the present invention has the following practical advantages: 
     1. In comparison of the rectangular core components with the conventional round core components having the same cross-sectional areas, the surface area of the rectangular core components is larger than that of the conventional round core components, thereby, the transmission area of the rectangular core components is increased, this can lower the attenuation of and increase the speed of signal transmission. 
     2. The dielectric coefficient of the Teflon in the wrapping roll made from foamed Teflon (PTFE) tapes over the core components is largest, hence an excellent insulation effect can be obtained, and the degree of mutual interference can be reduced to the minimum; 
     3. The core portion and the hollow tubes of the middle filler layer are twisted in an identical direction; this reinforces the signal line and increases the flexibility of the signal line, so that the signal line will not deform during bending to damage the core portion, and the core components of the core portion can be kept parallel to each other. 
     The structure of signal line of the present invention can have an effect of efficiently obscuring by providing the core portion and the obscuring layer, thereby can effectively prevent interference among a magnetic field, radio frequencies and static electricity; such a signal line is surely brand-new as compared to the lines available presently, functional improvement thereof is evident.