Abstract:
A poolside connector system and method for use with swimming pool race timing systems and signaling devices. A deck plate or similar poolside signal junction is provided with an optical receiver terminal, and a cable connection from a poolside signaling device such as a touchpad or backup button is provided with an optical transmitter terminal that can be plugged into the deck plate terminal. Electrical signals from the touchpad and backup button representing completed laps are transmitted as optical signals to the deck plate junction. The optical connection at the deck plate is non-conductive and electrically sealed from the poolside environment, and thus has no exposed electrical terminals to corrode. The low voltage DC current on which the optical terminals operate is provided in sealed fashion to the electrically insulated optical terminals, in a preferred form via an inductive power coupling whose halves are sealed in the deck plate and the removable cable connection.

Description:
FIELD OF THE INVENTION 
   The present invention is in the field of swimming pool deck connectors of the type used for connecting the various poolside timing components of a swim-race timing system. 
   BACKGROUND OF THE INVENTION 
   Electronic timing systems are commonly used for pool swimming races, with the recording of swimmers&#39; start times, lap times (often referred to as split times), and finish times commonly being triggered by switches known as “touchpads”. Referring to  FIGS. 1 and 1A , the touchpads are typically large, flat panels  16  mounted underwater against the end wall  14  of pool  10  at the end of each swimming lane  12 , positioned for a swimmer to make switch-closing contact with his hands or feet at the end of each lap. The touchpads  16  receive switch-operating power from a timing system  30  located near the pool, and send timing signals through permanent “deck plate” outlets  20  connected by buried conduit  21  to the timing system  30 . 
   An alternative to the permanent deck plate arrangement is a temporary deck cable (not shown, but well known) with touchpad and backup button connections similar to those in the deck plates. For illustration, the deck cable corresponds to buried conduit  21  in  FIG. 1 , but lies temporarily on the surface of the pool deck  18  and is removed when the race event is over. The touchpad, backup button, and any other auxiliary device connections on the deck cable correspond in placement and function to the connections in deck plates  20 , but are spliced into the cable without the need for a rigid mounting structure, and are removed along with the cable at the end of the race event. 
   The timing system  30 , illustrated schematically as a timing “box” or controller  32  located at the pool “office”  34  (often an elevated timing table with assorted printers, displays, power source, controls, the timing box and computer) associates a start time, split time, or final time with each hit, and records and displays the times, for example transmitting them to scoreboard  38  via conduit  31 . To make sure that each swimmer&#39;s times are recorded in the event of a missed or faulty touchpad hit, it is common to have a human timer ( FIG. 1A ) on the pool deck  18  holding a manually-operated “backup button” switch  22 , which is plugged into a corresponding touchpad&#39;s deck plate  20  to deliver a “hit” signal to the timing system similar to that provided by the touchpad. 
   The deck plates  20  often have auxiliary power/data connections for speakers, lights, horns, and other peripheral devices shown schematically at  36 , allowing information to be communicated from the timing system back to the swimmers poolside. 
   The typical deck plate  20  is mounted flush in the concrete pool deck  18  adjacent each swimming lane  12 . Touchpad  16  and backup button  22  are connected to deck plate  20  through cables  16   a  and  22   a  ending in plugs  16   b  and  22   b  plugged into deck plate outlets  20   b . Plugs  16   b  and  22   b  and deck plate outlets  20   b  have mating metal electrical terminals  16   c ,  22   c  and  20   c . Swim race timing systems are typically powered by low voltage DC electrical current, usually on the order of 5VDC, so any exposed or water-shorted metal plug connections are safe. But the pool deck  18  is usually awash in chlorinated water, which quickly corrodes the metal terminals  20   c  in the deck plates. Frequent cleanings of deck plate terminals  20   c  to prevent corrosion and maintain connection quality usually make the problem worse, by abrading or chemically damaging the metal terminal surfaces. Even temporary deck cable terminals can suffer corrosion, although with some effort corrosion can be minimized by removing the cables and drying their terminals between meets. 
   Another problem with prior poolside timing system connectors is the need to supply electrical current to the switch-closing contacts in the touchpads and backup buttons. Direct (DC) current tends to increase corrosion of the conductive surfaces, such that at least one prior patent has suggested using voltages as low as 0.25 VDC for the touchpads to reduce corrosion of the conductive metal touchpad surfaces. The lower the DC voltage, however, the greater the line losses through the relatively small gauge wire connecting the various timing system components using that voltage, and the more the system is susceptible to noise. 
   BRIEF SUMMARY OF THE INVENTION 
   According to the invention, a connector system for a poolside race timing system comprises a photoelectric signal receiving junction located at an exposed portion of the pool deck adjacent a swimming lane, the signal receiving junction comprising a first photo-receiver plug terminal being electrically connected to a race timing system. A poolside signal generating device is associated with the swimming lane and comprises a low-voltage direct current circuit and the poolside signal generating device further comprises a switch from closing the low voltage direct-current circuit. The poolside signal generating device has a temporary cable connection to the signal receiving junction and the cable connection includes a photo transmitter plug terminal with an associated photo-transmitter device powered by low voltage direct current in response to the switch closing the low-voltage direct current circuit and is electrically sealed from the poolside environment. The photo-transmitter plug terminal is temporarily matable with the photo-receiver plug terminal at the signal receiving junction to deliver an optical signal to the photo receiver plug terminal at the signal receiving junction in response to the closing of the signal generating device switch. 
   In one embodiment, the signal receiving junction comprises a deck plate. Further, the signal receiving junction can comprise a deck cable as well as a touch pad and a backup button. 
   In another embodiment, the low voltage direct current for the photo transmitter device is derived from a non-conductive power coupling between the photo receiver plug terminal and the photo transmitter plug terminal at the signal receiving junction when the plug terminals are mated. Further, the non-conductive power coupling can comprise and inductive coupling with a transmitting portion in the signal receiving junction and a receiving portion in the photo-transmitter plug terminal. Still further, the inductive power coupling can comprise a transmitter coil in the signal receiving junction associated with the photo receiving plug terminal, and a receiving coil in the photo transmitter plug terminal. In a preferred embodiment, the inductive power coupling comprises a DC-AC inverting circuit in the signal receiving junction and an AC-DC converting circuit in the photo transmitting plug terminal. In addition, the DC-AC inverting circuit in the signal receiving junction can include an oscillator circuit, and the AC-DC converting circuit can include a rectifying circuit. Further, the rectifying circuit can include a charging capacitor. 
   In another embodiment, the photo receiver-device in the signal receiving junction and the photo-transmitter device of the photo-transmitter plug terminal are powered by low voltage direct electrical current from the race timing system. 
   In another embodiment, the photo receiver device in the signal receiving junction is powered by low voltage direct electrical current from the race timing system, and the photo-transmitter device of the photo transmitting plug terminal is powered by a battery associated with the poolside signal device. 
   Further according to the invention, a method for transmitting signals from poolside signal devices to a race timing system in a pool deck comprises generating an electrical signal at the poolside signal device, converting the electrical signal to a corresponding optical signal, and transmitting the optical signal across a temporary, non-conductive optical plug connection at an exposed portion of the pool deck to a photo-receiver in a sealed signal receiving junction at the exposed portion of the pool deck connected to the race timing system. 
   In one embodiment, the method further includes converting the optical signal received by the photo receiver to an electrical system readable by the race timing system. In another embodiment, the method further comprises supplying electrical power to the poolside signal device for the electrical signal through the non-conductive optical connection at the pool deck. Further, the method can include supplying the electrical power through the non-conductive optical connection at the pool deck with an inductive coupling. 
   These and other features and advantages of the invention will become apparent upon further reading of the specification, in light of the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plan view of a typical prior art timing system setup using deck plates mounted in the pool deck. 
       FIG. 1A  is a perspective view of the end of one of the swimming lanes from  FIG. 1 , showing prior art conductive electrical connections between a touchpad, a backup button, and one of the deck plates. 
       FIG. 2  is a perspective view of a deck plate and a cable from the touchpad with optical connector terminals according to the present invention, with the touchpad terminal separated from its mating deck plate terminal for clarity. 
       FIG. 3  is a side elevation view, in section, of the separated deck plate and cable terminals of claim  1 , with a schematically illustrated inductive power coupling in the terminals. 
       FIG. 4  is a schematic of the deck plate connector system of  FIGS. 2 and 3  incorporated into a timing system. 
       FIG. 5  is a schematic diagram of preferred inductive power supply and optical signal circuits for the connections of  FIGS. 3 and 4 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring first to  FIG. 2 , the invention is illustrated in a preferred example in which an optical deck plate  120  receives a mating optical signal cable  116   a  from a poolside signal device such as touchpad  16  or backup button  22 . Deck plate  120  includes optical connector sockets  120   b  corresponding in purpose to the multi-terminal electrical sockets shown in  FIG. 1A , but having no exposed metal contacts and requiring only a single terminal opening for receiving a one-part optical plug  116   b  at the end of cable  116   a . The “terminal” of optical plug  116   b  is a photo-transmitter device  116   c  of known type, for example a visible LED light source with a simple on/off signal state. It will be understood by those skilled in the art that other types of photo-transmitter can be used, for example an infrared or other non-visible LED or a laser light source such as an injection laser diode (ILD). Low-cost visible LED type devices are widely available, economical, and currently preferred for their ability to be visually verified. 
   Although the actual light emitter is shown in the terminal plug portion of cable  116   a , it will be understood that light could also be transmitted to the terminal end from an upstream source, for example by fiber optics. 
   Optical connector socket  120   b  in the deck plate includes a photo-receiver device  120   c , for example a phototransistor device of known type that reacts to an “on” light signal from the LED in the photo-transmitter  116   c  by generating an electrical “hit” signal. Other known types of photo-receiver device can be used, limited only by their compatibility with the signal from the photo-transmitter  116   c.    
     FIG. 2  also illustrates optional indicator lights  121  associated with each socket  120   b , coupled electrically to the output of photo-receivers  120   c  to momentarily light up when an optical signal is received from a touchpad or backup button through cable  116   a . Indicator lights  121  allow the optical connection to be tested poolside before a race, and during a race gives visual confirmation to the people timing the race that the system is working. 
   The materials used for cable  116   a  and deck plate  120  are conventional, for example a non-conductive rubber sheath over conductive wiring for the cable, and a hard, wear-resistant, non-conductive plastic for the deck plate. 
     FIG. 3  shows the optical connection between cable  116   a  and deck plate  120  in more detail. Plug  116   b  is made from a non-conductive material such as plastic or rubber, and schematically shows photo-transmitter  116   c  associated with a power source in the cable, in  FIG. 3  a preferred inductive coupling such as a transformer type conductive copper coil  130 , sealed in the non-conductive body of the plug. As shown in more detail in  FIG. 5 , and as will be understood by those skilled in the art, inductive coupling  130  is electrically connected in a circuit with photo-transmitter  116   c  and the touch pad or backup button switch contacts. When the touchpad or backup button switch contacts are closed, power is received inductively by coupling  130  from the deck plate socket and transferred to photo-transmitter  116   c , which produces a flash of light. 
   Other known types of inductive or non-metal power coupling might be used to transfer power across the optical connection, but the inductive copper coils shown in the illustrated example are simple, reliable, and currently preferred. 
   It is also possible to supply power to photo-transmitter  116   c  with a self-contained power source connected to cable  116   a , for example a small battery housed in the touchpad or backup button and connected through the switch contacts with the photo-transmitter.  FIG. 4  shows optional batteries B in hidden lines, located in the backup button  22  and in the touchpad  16 . 
     FIGS. 3 and 4  show photo-receiver terminal  120   c  mounted in socket  120   b  in the deck plate, with an associated inductive power coupling  132 . Like photo-transmitter  116   c  and coupling  130  sealed in the touchpad cable, photo-receiver  120   c  and coupling  132  are sealed inside the photo-receiver housing  120   d  or deck plate  120 , such that electric current transmitted to or from the coupling and photo-receiver is insulated from the poolside environment. Unlike the electrical circuit between the photo-transmitter  116   c  and coupling  130  in the touchpad cable, deck plate coupling  132  is not electrically connected to photo-receiver  120   c , but rather to supply wiring  134  from a known type of DC power supply associated with the race timing system. Photo-receiver  120   c  is connected on a separate circuit to wiring  136  that transmits the photo-receiver&#39;s optically-generated electrical signals to the timing system in the manner of conventionally-generated electrical signals. 
   It will be understood by those skilled in the art that inductive coupling  132  need not be built into the optical terminal  120   c  as shown, but could be built into the deck plate adjacent socket  120   b . It will also be understood that although  120   c  is shown as part of a screw-in terminal, it can be secured removably or permanently in the deck plate in different ways. 
   If the optical signal from photo-transmitter  116   c  is generated by a power source contained in the touchpad or backup button, the inductive coupling  130  can be omitted from the cable plug, and coupling  132  and power supply wiring  134  can be omitted from the deck plate. 
   The fit between plug  116   b  and socket  120   b  is preferably light-resistant and water-resistant, to maximize transmission and reception of the optical signal in the socket. In the illustrated embodiment of  FIG. 3  this is achieved with an elastomeric plug body  116   b  sized to fit snugly and somewhat resiliently in socket  120   b . It will be understood that other light-resistant and/or water-resistant connection types can be used, including but not limited to bayonet fittings, threaded fittings, plug fittings with threaded collars, snap-fittings, and the like. The shape and size of socket  120   b  and the manner and orientation in which photo-receiver  120   c  are mounted in the socket can also vary. 
   Inductive couplings  130  and  132  are brought into sufficient proximity by the mating of plug  116   b  with socket  120   b  ( FIG. 4 ) to inductively generate an electrical current in coupling  130  when an alternating current is passed through coupling  132  from the central power supply. This inductive electrical connection is fully sealed and insulated from the pool-side environment, without any exposed metal terminals, eliminating the corrosion concerns normally associated with poolside signal connections. 
     FIG. 4  shows both a touchpad  16  and a backup button  22  connected through cables  116   a  and  122   a  to deck plate  120  with optical connections as described above. Power is inductively received by the coupling  130  and stored by a capacitor. Each time a swimmer hits touchpad  16  or a race official hits backup button  22 , closing its switch contacts, the capacitor&#39;s charge is discharged through photo-transmitter  116   c  in respective plug  116   b  to generate an optical “hit” signal. The hit signal is optically received by the corresponding photo-receiver in deck plate  120 , converted to an electrical signal, and transmitted to the timing box  32  to record and display a lap time or race finish in known manner. 
   It will be understood that although touchpads and backup buttons are the poolside signal devices with which the invention is most likely to be used, other poolside electrical signal devices with terminal connections likely to be inundated with pool water can benefit from the invention. 
     FIG. 5  is a currently preferred schematic circuit diagram of the power supply, switching, inductive coupling, and photo-receiver/transmitter components illustrated in the example above. The circuit labeled  16 ,  116  represents the touchpad/backup button switching mechanism and the photo-transmitter and cable-side inductive coupling  130 ;  132  represents the inductive power coupling in the deck plate  120 , in the form of an oscillator circuit; and  120   c  represents the photo-receiver in the deck plate, in the form of a phototransistor circuit. The schematic position of circuit  16 ,  116  relative to the other circuits represents the touchpad cable plug  116   b  plugged into the deck plate socket  120   b.    
   In  FIG. 5 , 5VDC electric current is delivered from the timing box  32  through wiring  134  to oscillator circuit  132 . The oscillators U 2  are tuned to approximately 1.2 MHz with the components shown. The output of oscillators U 2  feeds the medium power E-line transistor Q 5  to provide alternating current (AC) sufficient to excite coil L 1 . The peak-to-peak amplitude of the coil output in the illustrated example is 15-20VAC. 
   The inductive coupling associated with the photo-transmitter circuit  116   c  has its coil L 5  placed sufficiently close to coil L 1  to inductively generate a corresponding current. Photo-transmitter coil L 5  has more turns than photo-receiver coil L 1 , resulting in the voltage being stepped up, for example to 20VPPK (high peak power). Diode D 5  rectifies the AC current to DC current and capacitor C 9  charges up to approximately 7-10 VDC, functioning like a short-term battery. The capacitor C 9  voltage provides the DC current needed to fire the HLMP red LED photo-transmitter when the touchpad switch S is closed by a swimmer&#39;s contact with the touchpad. 
   It takes approximately 500 mS to recharge capacitor C 9  after energizing it to fire the LED. An option not shown in the schematic of  FIG. 5  is a one shot to energize the oscillators U 2  for short bursts sufficient in time to recharge the capacitor before the next “hit” but significantly reducing power consumption and eliminating EMI interference, if desired. 
   Photo-receiver circuit  120   c  is an amplified phototransistor circuit with a photodiode D 1 , preferably with a fast rated response time on the order of 50 nS, and a quad type op-amp U 1  specialized for single supply low voltage operation. Light received from the LED in  116   c  is turned into a low voltage direct current electrical signal (5VDC, for example) by photo-receiver circuit  120   c  in known manner, and is delivered to the timing box  32  to record the swimmer&#39;s hit. 
   It will be understood that the inductively powered photo-transmitter circuit  16 ,  116  in  FIG. 5  can also be fitted in the backup button  22  and its cable and plug portions, with switch S consisting of the switch contacts in the backup button. 
   It will be appreciated by those skilled in the art that the inductive power supply circuitry of  FIG. 5  can be eliminated from the connector system if the photo-transmitter in the touchpad cable or in the backup button cable is powered by a battery contained in the touchpad or backup button. The inductive power coupling between the poolside optical signal-generating device and the optical deck plate is highly preferred, however, since it eliminates the need for battery maintenance and testing, and eliminates the need for a water-resistant battery housing on devices such as the touchpad or the backup button. 
   It will be further appreciated that the optical signal connection and its associated inductive electrical coupling may be adapted to transfer more than on/off “hit” signals and momentary enabling power between the timing system and poolside signal devices, although the illustrated system is designed specifically to carry out these primary functions. The disclosed embodiments are representative of presently preferred forms of the invention, but are intended to be illustrative rather than definitive of the invention. The scope of the invention is defined by the following claims.