Abstract:
A two part guidance system that can be added to any vehicle with a traditional ball hitch that provides guidance to the driver during the hitching process. A sensor plate holds multiple sensors in an orientation that surrounds the ball and the sensors provide position information regarding the trailer&#39;s tongue to the driver via a display box in the cab of the vehicle. The display box preferably includes selectively illuminated arrows that indicate to the driver which direction to go in order to align the ball directly underneath of the tongue. Detection signals are sent to the display box through a cable or wirelessly. The display box can receive electrical power from the vehicle&#39;s electrical system or from batteries.

Description:
BACKGROUND OF THE INVENTION 
   The present invention was originally disclosed in U.S. provisional patent application Ser. No. 60/524,304 filed on Nov. 24, 2003, and priority is claimed to the provisional patent application. 

   The present invention relates generally to the field of trailer hitches and more specifically to an electronic system for aligning the two parts of a trailer hitch. 
   A traditional trailer hitch comprises a socket, or tongue, located at the front of a trailer and a ball, which fits into the socket, located on the back of a towing vehicle. The ball can be secured to the rear bumper of the vehicle or the ball can be on a tow bar that is secured to the rear of the towing vehicle. When the two parts of the hitch are joined and locked in place, the ball cannot be removed from the tongue but the ball can rotate within the socket allowing the trailer to be pulled, and even pushed, in multiple directions. A problem with traditional trailer hitches is that the driver of the towing vehicle cannot see the ball or socket when he is trying to engage the two parts of the hitch. Coupling the ball and socket requires the driver to maneuver his vehicle rearward so that the ball is positioned underneath of the tongue of the trailer. Understandably, without being able to see either part of the hitch, traditional coupling requires multiple trial and error attempts. Even with assistance from a second person, the coupling process can be frustrating. Adding pressure to the whole situation is the fact that if the driver backs up too far, the trailer&#39;s tongue will hit and damage the back of the vehicle. 
   Electronic sensors are devices that respond to a given stimulus. Motion detectors are well known and traditionally used in the security field to sound an alarm when intruders are present. Motion detectors can be designed to respond to movement by causing a light to light up or by causing a noise to be created. Some detectors work in pairs, wherein a solid beam of light is maintained between a pair of sensors and the sensor is triggered by breaking the beam of light. Other sensors work independently, wherein each sensor sends out one or more signals, with no expectation of receiving a reflection of the signal(s), and the sensor is triggered when it does receive a reflected signal. Photoelectric sensors are electronic sensors that use changes in received light to detect the presence of an object. Diffuse reflection photoelectric sensors, which can be very small in size, can detect the presence of an object up to 23 inches away. Motion detectors and photoelectric sensors can be set to different sensitivities by raising or lowering the received signal threshold of each sensor, to a higher or lower threshold. A low threshold allows detection of far away movement/objects and a high threshold requires close movement/proximity for triggering the sensor. 
   Wireless communications are traditionally accomplished by embedding information on a carrier wave. Radio waves are most commonly used as the carrier waves. In simple applications, such as having a sensor indicate that some object has been detected, little or no information needs to be embedded in the carrier wave. By simply sending a radio signal upon detection of the object and not sending a signal otherwise, such systems can be produced with small amounts of logic and circuitry. Radio transmitters and receivers are well known and are currently available in sizes small enough to be used with the present invention. 
   What is needed in the field is an electronic device that can be added to any towing vehicle that provides directions to the driver of the vehicle during the coupling process. The ideal device would use multiple sensors positioned around the ball to detect the position of the trailer tongue. The sensors would provide positioning information to the driver that enables the driver to align the ball with the tongue. The sensors would be electrically connected to a display located inside the vehicle. The display box would preferably be positioned so that the driver can see and hear information from the box while the driver is seated in the driver&#39;s seat. The display would provide easy to understand left, right, backwards and stop signals to the driver. Electrical power could be supplied to the present device either directly from the vehicle&#39;s electrical system or from batteries. Communications between the sensors and the display box can be wireless or wired. 
   SUMMARY OF THE INVENTION 
   A guidance system that is adapted to be attached to a towing vehicle, wherein the guidance system provides visual and auditory signals to the driver of the vehicle, which aids the driver in hitching a trailer to a ball hitch on the rear of the vehicle. A sensor plate with a hole in the middle is secured underneath of the ball by removing the ball from the vehicle, passing the stem of the ball hitch through the hole in the sensor plate, and replacing the ball hitch in its original place on the vehicle. The sensor plate houses multiple sensors around the circumference of the plate with each sensor capable of detecting when an object is above it and subsequently sending a detection signal. Each sensor is electrically connected to a sensor plate cable, in the preferred embodiment, that provides power to the sensors and receives detection signals from the sensors. A display box that is adapted to be at least temporarily mounted within the cab of the vehicle receives the detection signals. The display box has on its front multiple lights and a speaker. The multiple lights include at least one light each for indicating to the driver that he should move the ball forward, backwards, left and right. The display box is adapted to be electrically connected to a power source in the vehicle or it can be battery powered. When the trailer&#39;s tongue passes within a selected distance over any sensor in the sensor plate, that sensor sends a detection signal to the display box. The display box receives all of the detection signals and causes one or more of the lights to illuminate, wherein the illuminated lights provide guidance to the driver for properly aligning the ball directly underneath of the tongue. 
   The multiple lights on the display box preferably include a left arrow, a right arrow, a backwards arrow, and a forward arrow for indicating which direction the driver should move. The multiple lights on the display box may also include a large central light that lights up when the ball is properly aligned with the tongue, indicating that the driver should stop. The display box may also include four smaller lights dispersed on top of, below of, to the left of, and to the right of the large central light, for indicating progress to the driver. The speaker in the display box preferably provides beeps when the tongue has been detected by any of the sensors and a solid tone when the ball is properly aligned for hitching with the tongue. 
   It is an object of the present invention to aid drivers that must hitch a trailer to their vehicle. 
   It is another object to provide a guidance system that can be added to any vehicle with a traditional ball hitch and thereafter aid the driver in hitching the vehicle to any trailer. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention of the present application will now be described in more detail with reference to the accompanying drawings, given only by way of example, in which: 
       FIG. 1  is a top view of the sensor plate in the preferred embodiment; 
       FIG. 2  is a frontal view of the display in the preferred embodiment; 
       FIG. 3  is a side view of the sensor plate in its operational position; 
       FIG. 4  is a top view of an alternative embodiment of the sensor plate; 
       FIG. 5  is a side view of the embodiment shown in  FIG. 4 ; and, 
       FIG. 6  is a frontal view an alternative embodiment of the display. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention is designed to be attached to any towing vehicle with a traditional ball hitch attached to the rear of the vehicle. No special ball is needed and no addition or alteration to the tongue of the trailer is needed for this invention to be used. The preferred embodiment of the present sensor plate  100  is shown in  FIG. 1 . Sensor plate  100  includes six sensors  101 – 106 , which are C18D-AP-1A photoelectric sensors offered by AutomationDirect.com in the preferred embodiment. The sensor plate  100  is generally circular in shape with one flat side that is designed to face the towing vehicle. The shape of the sensor plate  100  shown in  FIG. 1  is designed to allow attachment to towing vehicles that do not have much room between the ball and the bumper, or other rear portion, of the towing vehicle. The sensor plate can be provided in other shapes besides circular, as will be discussed in conjunction with  FIG. 4 , below. Five of the sensors  101 – 105  are arranged around the periphery of the plate  100  in an extended semi-circle, with each of the five sensors  101 – 105  facing upward. Each sensor  101 – 105  acts like a small radar unit by detecting when an object is directly above any of the sensors  101 – 105 . The area of interest in this case is small, approximately one foot above the sensor plate  100 . The sixth sensor  106  is angled rearwardly at approximately 45° so that it faces toward the trailer to be hitched. The sixth sensor  106  allows the present system to detect the tongue of the trailer when it is approximately two feet from the ball  110 . Once the trailer&#39;s tongue has been spotted by sensor  106  a light on a display box in the cab of the vehicle is illuminated indicating to the driver that the tongue is approximately two feet from the ball and he should continue backing up. The entire radar hitch system is designed to be powered by the 12-volt electrical system of the towing vehicle. In alternate embodiments, other types of sensors including motion detectors can be used and batteries can be used to provide electrical power to the system. 
   The present radar hitch system allows a driver to attach a trailer to the back of a vehicle without the need of a second person providing directions to the driver. The system uses the multiple sensors  101 – 106  to detect the position of the trailer tongue. The sensors provide positioning information to the driver that enables the driver to align the ball  110  with the tongue of the trailer. The sensors  101 – 106  are electrically connected to a display box (see  FIG. 2 ) that is located inside the vehicle. When a sensor detects an object above it, or in front of it in the case of sensor  106 , the sensor causes one or more associated lights on the display box to light up. Electrical power is delivered to the sensor plate  100 , and tongue position information is sent to the display box, via cable  115 , which includes a quick-connect coupler in the preferred embodiment. 
     FIG. 2  shows an exemplary display box  200  of the present radar hitch system that receives trailer tongue position information from the sensors via cable  201 . The display box  200  receives electrical power from a power cord  202 . Of course, if batteries are used to power the display box  200  then power cord  202  is unnecessary. The display box  200  is positioned within the cab of the towing vehicle so that the driver can see and hear information from the box  200  while the driver is seated in the driver&#39;s seat of the vehicle. The display box  200  provides easy to understand guidance signals, such as arrow lights  205 ,  210 ,  215  and  220 , circular lights  230 ,  235 ,  240 ,  245  and  250 , and beeps and/or solid tones from speaker  255  that aid the driver in hitching the trailer to the vehicle. In an alternate embodiment, the speaker is used to provide verbal directions, including “back up slowly”, “go right”, “go left” and “stop”, to the driver. Working in conjunction with the sensors, the display box  200  indicates to the driver when the ball hitch needs to be moved left, right, backwards, and when the driver should stop. For purposes of this description, left and right directions are provided from the perspective of the driver of the vehicle while facing forward in the driver&#39;s seat. In the preferred embodiment, if the sensor plate detects the trailer&#39;s tongue to the left of the ball, then the left arrow  210  is illuminated indicating to the driver that he must maneuver the ball to the left. As the tongue is brought closer to the ball, circular light  235  is illuminated indicating to the driver that he is making progress. Similarly, if the sensor plate detects the trailer&#39;s tongue to the right of the ball, then the right arrow  215  is illuminated indicating to the driver that he must maneuver the ball to the right for proper alignment. As the tongue is brought closer to the ball, circular light  240  is illuminated indicating to the driver that he is making progress. When the tongue is directly over the ball and trailer&#39;s tongue is ready to be lowered onto the ball, all lights on the display box  200  are turned off except for the large central light  250 . Central light  250  is preferably red in color and the largest light on the display box  200 . When this large, red light comes on, it indicates to the driver that he can stop the vehicle because the ball is in the home position and the tongue is ready to be lowered onto the ball. The home position being defined as when the tongue is directly over the ball and hitching of the two parts is possible. The smaller circular lights  230 ,  235 ,  240  and  245  can be any color but are preferably yellow or orange. The arrow lights  205 ,  210 ,  215  and  220  may also be any color but are preferably green. This color scheme follows that of a traditional stoplight, wherein green indicates go, yellow indicates slow down, and red indicates stop. Electrical power can be supplied to the display box  200  via power cord  202  either directly from the fuse box of the vehicle or via a cigarette lighter adapter. 
     FIG. 3  is a side view of the preferred embodiment of the sensor plate  100  in its operational position. The sensors of the present device are preferably housed within a thin metal plate, however other materials including plastics could be used in other embodiments. The metal sensor plate  100  is held in place by removing the ball  110  from the bumper  300  or tow bar of the vehicle and placing stem  310 , or ball support arm, of the ball through a hole that is provided near the center of the sensor plate  100 . The ball is then replaced in its original position on the vehicle thereby securing the sensor plate  100  in its operational position with the use of nut  305 . The electrical connections  115  to and from the sensor plate preferably include a quick-connect coupler for easy connection and disconnection. Quick-connect couplers are well known in the trailer industry. In an alternative embodiment, the sensor plate includes at least one battery and a wireless connection is used between the sensors and the display box. Applicant knows of no other device that provides a hitching guidance system that can be installed on any traditional hitch ball and thereafter can be used with any trailer, i.e., there is no special equipment that must be attached to the trailer. 
     FIG. 4  shows an alternative embodiment of the sensor plate  100 , which can be used on vehicles with U-Haul hitches, Reece hitches and other equipment that extends the ball  110  further away from the rear of the vehicle than a traditional ball hitch attached to the bumper of the vehicle. In these extended hitches, the ball is permanently attached to a metal support bar that has a square cross-section. The metal bar is adapted to be inserted into a square socket that is permanently attached to the rear of the towing vehicle. In this embodiment, the sensor plate  100  includes seven sensors  101 – 105  and  400 . The sixth sensor  400  is positioned between the ball  110  and the towing vehicle (not shown). The sixth sensor  400  can indicate to the driver that he has backed up the towing vehicle too close to the tongue, since tow bars extend the ball away from the vehicle a distance that allows this scenario to occur. The angled sensor  103  serves the same purpose as the angled sensor in the preferred embodiment, i.e., it detects the tongue first at approximately two feet away. Sensors  101  and  105  can work in conjunction with sensor  400  to allow the present guidance system to indicate whether the driver is too close left or too close right. Referring back to  FIG. 2 , a situation of too close left would be shown in the display box  200  by the illumination of arrows  205  and  215 . These arrows would tell the driver to move the ball (rear of the vehicle) forward and to the right; until the large red light  250  in the middle of the display box  200  is illuminated. The sensor plate  100  is permanently attached to the support bar  405  in this embodiment. 
     FIG. 5  is a side view of the embodiment shown in  FIG. 4 . Sensor plate  100  is permanently attached to the top of support bar  405 . The sensor plate  100  can be welded to existing U-Haul and Reece&#39;s hitches or both parts could be produced as one piece. The support bar  405  is placed in its operation position by sliding the end  500  of the bar into a socket that is attached to the towing vehicle. Cable  115  carries detection signals to the display box and delivers electrical power to the sensors. Of course, if battery power is used and the detection signals are delivered wirelessly, the cable  115  will not be needed. Sensor  103  provides the same function as in the preferred embodiment. Sensor  103  is the first sensor to detects the trailer&#39;s tongue when it is approximately two feet from the ball and sends a signal to the display box. 
     FIG. 6  shows an alternative embodiment of the display for present guidance system. In this embodiment, multiple lights  601 – 605  have been embedded in the rear view mirror  600  of the towing vehicle. Each light  601 – 605  is comprised of one or more light emitting diodes (LED&#39;s) in the preferred embodiment. The lights  601 – 605  can be used in multiple combination based on the detection signals received from the sensor plate. Preferably, arrow light  602  is initially illuminated when the sensor plate first “sees” the tongue of the trailer. The other arrow lights  601 ,  603  and  604  then light up as needed, instructing the driver to maneuver the ball in the indicated direction. When the ball is finally in the home position, the center light  605  is illuminated. In another embodiment, the display box is adapted to attach to the vehicle&#39;s rear view mirror. The present two piece invention will greatly aid the hitching of boat trailers to towing vehicles, however the invention will also help in the hitching of mobile homes, campers and other trailers to towing vehicles as well. 
   The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept. Therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology of terminology employed herein is for the purpose of description and not of limitation.