Abstract:
A communication cable which takes the form of an elongated flexible conductor which has mounted at one end thereof a transmitting connector and at the opposite end thereof a receiving connector. The conductor has integratingly mounted therein a plurality of optical fibers and a plurality of electrical wires. The transmitting connector includes a light emitting device for each optical fiber and a flexible printed circuit board holding electronic circuitry for converting electrical signals into optical signals. Further, the transmitting connector has an electrical interface accessible by the user. The receiving connector includes a photodetector for each optical fiber and also a flexible printed circuit board holding electronic circuitry for converting optical signals back to electrical signals. The receiving connector also has an electrical interface accessible by the user.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a communication cable and more specifically to a communication cable which is constructed to include both electrical wires and optical fibers. 
   2. Description of the Related Art 
   In the operation of machines that are computer controlled, there is required a communication cable. The communication cable would extend between the machine and the computer. Typical machines or pieces of equipment would be metal forming machines or any machine whose operation is controlled by computer. 
   It is common that the computer is spaced some distance from the machine. To connect the machine to the computer a cable is required. Normally, in a place of business, there will be several machines. Each of these machines produce electromagnetic interference (EMI) or radio frequency interference (RFI). There also can be produced ground loops and ground currents. The typical cable that interconnects the machine to the computer basically contains just electrical wires. The transmission of the electrical signals over these electrical wires can be interfered with by the EMI, RFI, ground loops and or ground currents. This interference can result in incorrect control signals being supplied from the machine to the computer or vice versa. In the past, this problem, though relatively common, has been just lived with as there has not been any known structure that has been available to correct the problem. Extensive shielding, extra heavy ground wires and in general keeping cables short allowed the systems to work. In some cases marginally. 
   One way in which to avoid this kind of interference with electrical wires is to eliminate the electrical wires so that the control signals are not transmitted along electrical wires. One way this could be done is by using of fiberoptics. However, in the past, fiberoptic cables were relatively mechanically sensitive and frequently installations could be somewhat abusive. The result was the fiberoptic cable broke or deteriorated to where it was inoperative. The fiberoptics only needs to be used in conjunction with the control signals. The power that is transmitted between the computer and the machine can be transmitted by electrically conducting metallic wires as the power transmitting wires are sensitive to the EMI and RFI. 
   There is a need to construct a cable which includes not only electrical wires for transmitting of power but also fiberoptics for transmitting of control signals. The cable must be constructed to withstand abuse, and because it looks and functions just like a regular electrical cable, the user can be completely unknowledgable of the fact that it is a fiberoptic cable. The use of such a cable would be extremely critical and desirable in sensitive applications thereby completely avoiding any kind of electronic or electrical interference to the control signal. 
   SUMMARY OF THE INVENTION 
   A first embodiment of communication cable of this invention includes a transmitting connector and a receiving connector. In between the transmitting connector and the receiving connector is located an elongated, flexible conductor. Included within that conductor is a fiberoptic assembly of at least one optical fiber and a wire assembly of at least one metallic wire. The wire is to conduct electrical power and the fiber is to conduct light pulses. The transmitting conductor includes a light emitting diode or laser diode connected to the fiber. The light emitting diode is to receive an electrical signal and then convert such into a corresponding light signal which is transmitted through the fiber to be reconverted back to an electrical signal at the receiving connector. 
   A further embodiment of the present invention is where the first basic embodiment is modified by there being included within the transmitting connector a first flexible printed circuit board and within the receiving connector a second flexible printed circuit board. 
   A further embodiment of the present invention is where the first basic embodiment is modified by the wire assembly comprising a plurality of spaced apart wires and the fiber assembly comprises a plurality of spaced apart optical fibers. 
   A further embodiment of the present invention is where the first basic embodiment is modified by the optical fibers being fixedly mounted within both the transmitting connector and the receiving connector. 
   A second basic embodiment of the present invention is directed to a connector for a communication cable which comprises a housing with a light pulse receiver being mounted within the housing. The light pulse receiver is connected to a flexible printed circuit board. The printed circuit board is also mounted within the housing. A light source is connected to the housing with the light source to supply a light pulse to the light pulse receiver. An electrical signal output connector is connected to the printed circuit board with the electrical signal output connector adapted to receive an electrical signal from the printed circuit board and transmit same to an external machine. 
   A further embodiment of the present invention is where the second basic embodiment is modified by the light source being defined as a flexible cable. 
   A further embodiment of the present invention is where the just previous embodiment is modified by the cable being defined as including a plurality of separate optical fibers and also a plurality of separate electrical conducting wires. 
   A further embodiment of the present invention is where the second basic embodiment is modified by the cable being fixedly mounted to the housing so the light source is not capable of any movement relative to the cable which would result in non-transmission of the light pulse. 
   A third basic embodiment of the present invention is directed to a connector for a communication cable which comprises a housing with there being included within the housing a light pulse emitter. The light pulse emitter is connected to a flexible printed circuit board. The flexible printed circuit board is also mounted within the housing. A light pulse receiver is connected to the housing with the light pulse receiver to receive a light pulse from the light pulse emitter and transmit same to an output path located exteriorly of the housing. 
   A further embodiment of the present invention is where the third basic embodiment is modified by the output path being defined as a flexible conductor. 
   A further embodiment of the present invention is where the just previous embodiment is modified by the conductor being defined as being formed of a plurality of spaced apart optical fibers and a plurality of spaced apart electrical connecting wires. 
   A further embodiment of the present invention is where the third basic embodiment is modified by the optical fibers being fixedly mounted to the housing so the light pulse emitter is not capable of any movement relative to the housing. 
   A fourth basic embodiment of the present invention is directed to a method of communicating between a computer and a machine comprising the step of installing between the computer and the machine a communication cable that has both electrical wires for power transmission and optical fibers for transmitting of control signals. 
   A further embodiment of the present invention is where the fourth basic embodiment is modified by prior to the installing step there is the additional step of constructing the cable so the optical fibers are fixed in position within end connectors. 
   A further embodiment of the present invention is where the just previous embodiment is modified by installing within the end connectors a flexible printed circuit board. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference is to be made to the accompanying drawings. It is to be understood that the present invention is not limited to the precise arrangement shown in the drawings. 
       FIG. 1  is an exterior, longitudinal, side elevational view of the communication cable constructed in accordance with this invention with the cable being broken so as to indicate that the cable could be constructed of any desirable length; 
       FIG. 2  is an exploded isometric view showing the construction of the internal components within the end connectors that comprise the transmitting connector and the receiving connector that is included at opposite ends of the communication cable of the present invention; 
       FIG. 3  is a transverse cross-sectional view through the elongated, flexible conductor of the communication cable of the present invention taken along line  3 — 3  of  FIG. 2 ; and 
       FIG. 4  is an electrical schematic for the communication cable of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring particularly to the drawings, there is shown in  FIGS. 1–3  the communication cable  10  of this invention. Communication cable  10  is formed of an elongated flexible conductor  12  which can be any desired length, normally from a few feet to thirty, forty, fifty feet or more in length. The conductor  12  is basically cylindrical, however any desired shape could be utilized. Conductor  12  is formed of an outer cover  14  which is in the shape of a tube which has an internal chamber  16 . The cover  14  will normally be constructed of a plastic, rubber or other similar type of insulating material. 
   Centrally located within the internal chamber  16  is a strength member  18 . The strength member  18  will normally be constructed of any material that has a high tensile strength. Typical desirable materials would be steel, carbon fiber or a material that is sold under the trademark of Kevlar. Whatever material that is selected for the strength member  18 , it is the primary requirement that the strength member  18  not be stretchable but will remain in its established length. The length of the strength member  18  will extend the entire length of the conductor  12 . Also contained within the internal chamber  16  are at least one pair of spaced-apart metallic wires  20  and  22  and three in number of optical fibers  24 . However, it is considered to be within the scope of this invention that there could be more optical fibers  24  or even fewer in number of optical fibers  24 . Also, in all probability there will be a greater number of the wires  20  and  22 . The wires  20  and  22  will commonly be constructed of copper. The optical fibers  24  would generally be constructed of a glass. The wires  20  and  22  are used for conducting of electrical power and non-critical electrical signals. The optical fibers  24  are to be used for the conducting of control signals. 
   Mounted about the conductor  14  directly adjacent each end thereof is a strain relief and moisture seal boot  26 . Normally this boot  26  will be constructed of a plastic or rubber material. The boot  26  is to be telescopingly mounted or otherwise attached on narrow end  28  of a backshell  30 . The back shell  30  is a housing cover. The backshell  30  is part of a transmitting connector  32  at one end of the conductor  12  and also at the opposite end of the conductor  12  is part of a receiving connector  34 . As will be explained further on in the specification, there is a very minor difference in the construction between the connectors  32  and  34  so it is to be understood that the explanation, as far as the constructional features of the connectors  32  and  34 , will apply to both connectors  32  and  34 . 
   The backshell  30  has an internal chamber which is not shown. Confiningly located within this internal chamber is an O-ring seal  36 . Also located within this internal chamber of the backshell  30  is a jacket  38 . The jacket  38  will be fixedly connected to the conductor  12 , usually by crimping. It is important that the physical attachment between the jacket  38  and the cable  12  to be such as to establish a physical connection with the strength member  18 . The jacket  38  includes a pair of longitudinal slots  40  with only one such slot  40  being shown. The slots  40  are diametrically located apart relative to the jacket  38 . The jacket  38  is basically cylindrical in configuration forming a narrow cylinder at its outer end and an enlarged cylinder at its inner end which are separated by an annular tapered section. 
   Each, optical fiber  24  is mounted within a ferrule  42 , with it being understood that there are three in number of the ferrules  42 , one for each optical fiber  24 . Each ferrule  42  is then mounted within a hole  44  formed within an adapter  46 . The adapter  46  includes an externally knurled section  48  which is to crimping connect within the internal chamber of the jacket  32 . The ferrules  42  are precisely positioned within the adapter  46  so the outer end of each ferrule  42  will be located directly against the photodiode or LED  50 . The three in number of photodiodes/LED  50  are fixedly mounted onto a printed circuit board (PCB)  52 . Two pins  54  will engage within a hole, not shown, which is formed within the adapter  46  so the screws  54  functions as a position locator when mounting the photodiodes/LED  50  relative to the ferrules  42 . 
   The transmitting connector  32  will include light emitting diodes. The receiving connector  34  will include photodiodes. The photodiodes receive light which is then used to produce an electrical signal. Light emitting diodes produce light from an electrical signal. The printed circuit board  52  is connected to a flexible printed circuit board  58  which is basically U-shaped in configuration. Mounted on the printed circuit board  58  are a mass of electronic components which are necessary to transform the electrical signals into light pulses in the transmitting connector  32 , or to change the light pulses from the optical fibers  24  to an electrical signal in the receiving connector  34 . The reason the printed circuit board  58  is made flexible is so that it can readily fold and fit within the confines of an internal chamber  60  formed within an adaptor housing  62 . The adaptor housing  62  has a threaded section  64  that is to threadingly engage with an internally threaded section formed within the backshell  30  forming basically an airtight and watertight connection therebetween. The wall surface of the internal chamber  60  abuts against the O-ring seal  36  which rests within the annular groove  66  of the adapter  46 . 
   The disc  52  is mounted on one side of the printed circuit board  58  with a female pin connection member  68  being mounted on the opposite side of the printed circuit board  58 . This female pin connection member  68  is to connect with pins  70  that are mounted within internal chamber  72  which is formed within a connector housing  74 . The connector housing  74  will be connected to an optical encoder mounted to a machine, which is not shown. The machine could be any machine that is operated by the use of a computer or programmable logic controller, which is again not shown. The receiving connector  34  will be connected to a computer, which is again not shown. 
   Wire  20  is conducted out through a slot  40  and then longitudinally through a longitudinal groove  76  formed within the exterior surface of the adaptor  46 . In the same manner, the wire  22  is conducted through the diametrically opposite slot  40  and then longitudinally through a groove  78  formed within the exterior surface of adaptor  46 . The grooves  76  and  78  are diametrically located opposite each other. The wires  20  and  22  are then mounted each within a hole  80  formed within the female pin connection member  68 . The result is that the electrical power between connectors  32  and  34  is connected by the wires  20  and  22  completely separate from the optical fibers  24 . Control signals that are conducted between the connectors  32  and  34  are transmitted solely through the optical fibers  24  between the connectors  32  and  34 . 
   The connector housing  74  has a threaded section  82  about which is to be located an O-ring seal  84 . The threaded section  82  is to threadingly engage within the adapter housing  62  by means of a set of female threads, which are not shown. 
   Referring particularly to  FIG. 4 , there is shown the electrical schematic for the communication cable  10  of this invention. The transmitting section is shown within dotted lines  86 . The receiving section is shown within dotted lines  88 . Within the transmitting section  86  are located a pair of lines  90  and  92  for each amplifier  94 . There are three sets of lines  90  and  92  and there are three of the amplifiers  94  with each set of lines  90  and  92  to connect with one of the optical fibers  24 . Each amplifier  94  is to connect with one of the optical fibers  24 . The amplifiers  94  function as a line receiver. Input electrical power is supplied from a source, which is not shown, from lines  98  and  100  and through a voltage regulator  96  to output lines  102  and  104  from the voltage regulator  96 . The output lines  102  and  104  are to supply the typical plus five volt input power to each of the amplifiers  94  and  106 . 
   The output of each amplifier  94  is to be supplied respectively to a separate transimpedance amplifier  106 . Each transimpedance amplifier  106  is to receive input power from the line  104 . The output of each transimpedance amplifier  106  is supplied to a light emitting diode (LED)  110 . The light pulse from each light emitting diode  110  is to be conducted to a separate optical fiber  24 . 
   The output from each of the optical fibers  24  is received by a photodiode  112  with it being understood that there is a separate photodiode  112  for each optical fiber  24 . The photodiodes  112  will be contained within the short cylinders  50  of the receiving connector  34  with the LEDs  110  being contained within the short cylinders  50  of the transmitting connector  32 . The output from the photodiodes  112  is transmitted to another transimpedance amplifier which is composed of a series arrangement of amplifiers  114  and  116 . Associated with each of the amplifiers  114  and  116  is a feedback resistor  118 . In between the amplifiers  114  and  116  is a resistor  120  setting the gain of amplifiers  116 . The voltage that is supplied to contacts  122  of each amplifier  114  is from contact  124  of a bias voltage line  126 . A resistor  128  connects the contact  124  to the ground line  98  creating a bias voltage. The input voltage of plus five to twelve volts is to be supplied to contact  130  of the biasing line  126 . 
   In between resistors  132  and  134  of the biasing line  126  is a contact  136 . The contact  136  is to be connected to contacts  138  that supplies a bias voltage into each of the amplifiers  116 . Power to each of the amplifiers  140  of the line driver is supplied by line  142  which connects through voltage regulator  144  to the positive power line  98  and the ground line  100 . The output from each of the line drivers  140  is an electrical signal that is basically a recreation of the electrical signal that is supplied between the lines  90  and  92 . Separating the lines  90  and  92  are connected together by resistor  146  for line impedance matching. 
   This invention has been discussed with there being LEDs  110  within connector  32  and photodiodes  112  within connector  34 . However, it is considered to be within the scope of this invention that the communication cable  10  could be constructed to be bidirectional. This could be obtained if instead of three LEDs  110  within connector  32  that one of two of the LEDs could be replaced with a photodiode similar to photodiode  112 . The same would be true for connector  34  where one or two of the photodiodes  112  of connector  34  could be each replaced with an LED similar to LED  110 . The cable  10  could then be used to not only send signals from a computer to a machine but also transmit feedback signals from the machine to the computer. 
   The discussion included in this patent is intended to serve as a basic description. The reader should be aware that the specific discussion may not explicitly describe all embodiments possible and alternatives are implicit. Also, this discussion may not fully explain the generic nature of the invention and may not explicitly show how each feature or element can actually be representative of a broader function or of a great variety of alternative or equivalent elements. Again, these are implicitly included in this disclosure. Where the invention is described in device-oriented terminology, each element of the device implicitly performs a function. Apparatus claims may not only be added for the device described, but also a method claim is added to address the method of making the invention. It should also be understood that a variety of changes may be made without departing from the essence of the invention. Such changes are also implicitly included in the description. These changes still fall within the scope of this invention. 
   Further, each of the various elements of the invention and claims may also be achieved in a variety of manners. This disclosure should be understood to encompass each such variation, be it a variation of any apparatus embodiment, a method embodiment, or even merely a variation of any element of these. Particularly, it should be understood that as the disclosure relates to elements of the invention, the words for each element may be expressed by equivalent apparatus terms or method terms—even if only the function or result is the same. Such equivalent, broader, or even more generic terms should be considered to be encompassed in the description of each element or action. Such terms can be substituted where desired to make explicit the implicitly broad coverage to which this invention is entitled. It should be understood that all actions may be expressed as a means for taking that action or as an element which causes that action. Similarly, each physical element disclosed should be understood to encompass a disclosure of the action which that physical element facilitates. Such changes and alternative terms are to be understood to be explicitly included in the description.