Patent Publication Number: US-2015069736-A1

Title: Towing Vehicle Guidance for Trailer Hitch Connection

Description:
BACKGROUND OF THE INVENTION 
     The present disclosure relates to hitching a towing vehicle to a trailer or other vehicle to be towed and relates particularly to a guidance system and a method for its use in guiding a towing vehicle accurately to a position in which a trailer hitch can be coupled between the trailer and the towing vehicle. 
     Many trailers such as horse trailers and camping trailers are towed behind vehicles such as pickup trucks or sport utility vehicles. While small utility trailers can often be hitched to such a towing vehicle by lifting the tongue of the trailer manually or by moving the tongue of the trailer while its weight is supported on a stand including a wheel or skid, many trailers are large enough so that hitching them to a towing vehicle requires that the towing vehicle be backed accurately to a position in which a trailer hitch ball mounted on the towing vehicle is immediately beneath the coupler carried on the trailer or other vehicle that is to be towed. 
     On most such towing vehicles the trailer hitch ball or other mating hitch device is not in view of the operator of the vehicle. Even in a pickup truck with its tailgate lowered, the trailer hitch ball is normally hidden from the direct field of view of the pickup truck operator. When the towing vehicle is, for example, a larger truck or a sports utility vehicle loaded with equipment to be used during a long trip, for example, the rearward visibility may be even more limited, so that backing the towing vehicle requires use of side-mounted mirrors. Backing a towing vehicle accurately into position then usually requires a driver operator to rely upon hand signals and voice commands from a second person in position to observe the approach of the towing vehicle toward the trailer. Even for an experienced team of a driver and a signaling person such an operation is difficult, since the final position of the towing vehicle must be accurate within a fraction of an inch. 
     Many vehicles are now equipped with rearwardly-directed video cameras communicating with video monitors in view of the driver. Even when a trailer hitch member on a towing vehicle is in view of such a camera, however, backing a vehicle into the exact position required for a hitch to be coupled is, at best, difficult and uncertain. 
     Schultz U.S. Patent Application Publication No. 2005/0193603 shows use of a video camera mounted on the rear of a truck in connection with backing the truck to a required position for connection of a trailer hitch, but shows no way to indicate when the towing vehicle is precisely in the required position. 
     A team of a driver and a signaling person with little experience, or who only rarely hitch a towing vehicle to a trailer, can experience great difficulty, often requiring many approach attempts before the towing vehicle can be placed in the correct position. When the operation is not quickly successful, it can cause considerable disagreement, blame-laying, and unhappiness, thereby often creating interpersonal stress between people who are attempting to achieve relaxation and enjoyment of travel with a recreational vehicle. 
     While towing a large trailer such as a recreational vehicle, visibility to the rear of the towing vehicle is greatly obstructed and restricted. Side mirrors on the towing vehicle afford only a limited field of view, particularly behind the vehicle being towed, and backing such a large trailer therefore has often required guidance from a person on the ground, as when the trailer must be backed into a parking spot in a campground. 
     What is desired, then, is apparatus and a method for its use to facilitate backing a towing vehicle accurately into the required position where a trailer can be coupled to the towing vehicle without the need for directions or hand signals from a second person. Ideally, such apparatus could also be used to provide the operator of the towing vehicle with a clear view of an area behind the towing vehicle during the operation of moving the towing vehicle into position for coupling a trailer hitch, and also to provide a view of areas behind the towed vehicle. 
     SUMMARY OF THE DISCLOSURE 
     The apparatus and method disclosed herein, as defined in the claims included herein, which form a part of the present disclosure, provide answers to some of the aforementioned needs. 
     In one embodiment of an apparatus for guiding operation of a towing vehicle as it is moved to a position in which a trailer hitch can be mated, a camera mounted on the towing vehicle provides an image that can be viewed by the operator of the towing vehicle, showing the front of the trailer and a light beam projected from the towing vehicle toward a target mounted near a part of the trailer hitch on the vehicle to be towed. 
     In an embodiment of one aspect of the apparatus there is a target to be attached to a hitch component on a trailer that is to be towed, a light beam projector to be attached to a hitch component on the towing vehicle, and a camera to be carried on the towing vehicle in a location where the camera can form and transmit an image to a display that can be viewed by an operator of the towing vehicle as the towing vehicle is backed toward the required hitch-mating position for connecting the towing vehicle to the trailer. 
     In one embodiment of the apparatus a laser or other light beam projector is located on the towing vehicle so that it projects a light beam onto the target to indicate visibly the relative positions of the hitch portions that must be connected. 
     According to one aspect of a method disclosed herein for facilitating moving a towing vehicle into a required position relative to a trailer, so that a pair of hitch components can be mated with each other to connect the trailer with the towing vehicle, a target for a light beam is provided on the trailer, a light beam projector is provided on the towing vehicle, and the towing vehicle is backed toward the required mating position of the hitch components while the operator observes an image of the target and the hitch component on the trailer, provided by a camera located on the towing vehicle, and steers the towing vehicle so that the light beam is projected onto the target and can be observed in the camera image as an indication of the position of the towing vehicle relative to the trailer. 
     The foregoing and other features and advantages of the disclosed apparatus and method will be more readily understood upon consideration of the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL DRAWINGS 
         FIG. 1  is a simplified isometric view of a portion of a trailer tongue including a hitch coupler and a trailer hitch ball mounted on a drawbar portion of a trailer hitch on a towing vehicle, with the towing vehicle in position for the trailer to be coupled to the towing vehicle. 
         FIG. 2  is an isometric view at an enlarged scale of the trailer hitch ball and portion of a trailer tongue shown in  FIG. 1 , with an embodiment of a hitch alignment facilitating apparatus mounted on the trailer tongue and the hitch ball of the trailer hitch. 
         FIG. 3  is a partially diagrammatic view of a rear end of a towing vehicle and a front end of a trailer equipped with the hitch alignment facilitating apparatus shown in  FIG. 2 , with the towing vehicle in an initial position with respect to the trailer in preparation for backing toward the trailer in order to hitch the trailer to the towing vehicle. 
         FIG. 3A  is a top plan view of a portion of the trailer tongue and a trailer-mounted module as shown in  FIG. 3 . 
         FIG. 4  is a side elevational view of parts of the trailer and towing vehicle shown in  FIGS. 2 and 3 , showing the towing vehicle and trailer-mounted modules of the hitch-alignment facilitating apparatus in their operative positions. 
         FIG. 5  is a partially sectional and simplified side view taken in the direction of line  5 - 5  in  FIG. 2 , showing a towing vehicle-mounted module of the hitch alignment facilitating apparatus shown in  FIGS. 2 ,  3 , and  4 , mounted on a trailer hitch ball, as well as a trailer-mounted module of the apparatus and a coupler portion of a trailer hitch, with the coupler aligned with the trailer hitch ball. 
         FIG. 6  is a view taken at an enlarged scale in the direction of the line  6 - 6  in  FIG. 5 , showing the front target portion of the trailer-mounted module of the hitch-alignment facilitating apparatus disclosed herein. 
         FIG. 7  is a sectional view of the trailer-mounted, or target, module of the apparatus, taken along line  7 - 7  in  FIG. 5 , at an enlarged scale. 
         FIG. 8  is a side elevational view of a portion of a trailer tongue with a trailer-mounted module carried on a retractable arm attached to the trailer tongue. 
         FIG. 8A  is a side elevational view of a portion of a trailer tongue, with a retractable trailer-mounted module on a slide track attached to the trailer tongue, as well as a portion of a towing vehicle bumper and trailer hitch, with the towing vehicle module carried on a retractable slide. 
         FIG. 9  is a view of a display monitor screen located within the towing vehicle in position for viewing by the towing vehicle operator, displaying an image transmitted by a video camera portion of the towing vehicle-mounted module of the hitch-alignment facilitating apparatus disclosed herein while the towing vehicle is moving backward toward the trailer with the towing vehicle and trailer in the respective positions represented in  FIG. 4 . 
         FIG. 10  is a view similar to  FIG. 9 , with the display monitor screen showing the image produced and transmitted by the camera with the towing vehicle approaching the trailer more closely. 
         FIG. 11  is a view of the camera image shown in the display monitor in the towing vehicle operator&#39;s view when the towing vehicle is within a few inches from the hitch-mating position with respect to the trailer represented in  FIG. 5 . 
         FIG. 12  is a view of the camera image shown in the display monitor in the towing vehicle operator&#39;s view when the towing vehicle and trailer are in the respective positions represented in  FIG. 5 . 
         FIG. 13  is a view showing a portion of the towing vehicle-mounted module of the hitch alignment facilitating apparatus mounted on the rear of a trailer. 
         FIG. 14  is a simplified view of a hand-held separate module including a mobile telephone and a display showing an image transmitted by the camera in the towing vehicle module, similar to the image shown in  FIG. 11 . 
         FIG. 15  is a perspective view of a display device showing a pair of displays of the image transmitted by the camera in the towing vehicle module, in a device similar to a pair of glasses. 
         FIG. 16  is an isometric partial view of a rear end of a towing vehicle and a front end of a trailer equipped with the another embodiment of a hitch alignment guidance apparatus, with the towing vehicle in an initial position with respect to the trailer, in preparation for backing the towing vehicle toward the trailer in order to hitch the trailer to the towing vehicle. 
         FIG. 17  is an isometric view, at an enlarged scale, of the trailer hitch ball and a portion of the trailer tongue shown in  FIG. 16 , with modules of the hitch alignment facilitating apparatus mounted on the trailer tongue and the hitch ball of the trailer hitch. 
         FIG. 18  is a side elevational view of parts of the trailer and towing vehicle shown in  FIGS. 16 and 17 , showing the towing vehicle and trailer-mounted modules of the hitch-alignment facilitating apparatus in their operative positions. 
         FIG. 19  is a sectional side view at an enlarged scale, taken in the direction of line  19 - 19  in  FIG. 17 , showing a towing vehicle-mounted module of the hitch alignment facilitating apparatus shown in  FIGS. 16 ,  17 , and  18  mounted on a trailer hitch ball, as well as a trailer-mounted module of the apparatus and a coupler portion of a trailer hitch, with the coupler aligned with the trailer hitch ball. 
         FIG. 20  is a top plan view of a portion of the trailer tongue and the trailer-mounted module shown in  FIG. 19 . 
         FIG. 21  is an isometric view from the upper left rear of the towing vehicle-mounted module shown in  FIGS. 16-19 . 
         FIG. 22  is an isometric view from the upper right front of the towing vehicle-mounted module shown in  FIG. 21 . 
         FIG. 23  is an isometric view from the upper left rear of the body of the trailer-mounted, or target, module shown in  FIGS. 16-20 . 
         FIG. 24  is an isometric view taken from the lower right front of the trailer-mounted module shown in  FIG. 23 . 
         FIG. 25  is a front elevational view of the body of the trailer-mounted module shown in  FIGS. 23 and 24 . 
         FIG. 26  is a sectional view taken along line  26 - 26  in  FIG. 25 . 
         FIG. 27  is a view of a display monitor screen located within the towing vehicle in position for viewing by the towing vehicle operator and displaying an image transmitted by a video camera portion of the towing vehicle module of the hitch-alignment facilitating apparatus shown in  FIGS. 16-19  with the towing vehicle ahead of the trailer as represented in  FIG. 18 . 
         FIG. 28  is a view similar to  FIG. 27 , with the display monitor screen showing the image produced and transmitted by the camera of the hitch-alignment facilitating apparatus with the towing vehicle backed more closely toward the trailer. 
         FIG. 29  is a view of the camera image shown in the display monitor shown in  FIGS. 27 and 28  when the towing vehicle and trailer are in the respective positions represented in  FIG. 19 . 
         FIG. 30  is an isometric view from the upper left rear of a towing vehicle module which is another embodiment of the apparatus disclosed herein and which includes a pair of inwardly angulated light beam projectors. 
         FIG. 31  is a diagrammetric plan view of the towing vehicle module shown in  FIG. 30  mounted on a trailer hitch ball of a towing vehicle located a short distance ahead of a trailer on which a trailer-mounted module is mounted. 
         FIG. 32  is a view of a video monitor displaying an image transmitted from the video camera included in the towing vehicle-mounted module shown in  FIG. 30 , showing the trailer equipped with the trailer-module shown in FIGS.  19  and  23 - 26 . 
         FIG. 33  is a view of the video monitor shown in  FIG. 32 , with the towing vehicle a very short distance ahead of the hitch mating location with respect to the trailer shown in  FIGS. 31 and 32 . 
         FIG. 34  is a view of the video monitor of the apparatus showing the image generated by a video camera in the towing vehicle-mounted module shown in  FIG. 30  when the towing vehicle is in the hitch-mating position with respect to the trailer shown in  FIG. 31 . 
         FIG. 35  is an isometric view from the upper left rear of another embodiment of a towing vehicle-mounted module for the hitch-alignment guidance apparatus disclosed herein. 
         FIG. 36  is a view of a video monitor displaying an image created by a camera in the towing vehicle-mounted module shown in  FIG. 35 , when the towing vehicle-mounted module shown in  FIG. 35  is in use and the towing vehicle on which it is mounted is in the hitch-mating position with respect to a trailer equipped with the trailer-mounted module shown in FIGS.  19  and  23 - 26 . 
         FIG. 37  is a side elevational view of hitch-alignment facilitating apparatus in which a trailer-mounted module is located above a coupler portion of a trailer hitch and a towing vehicle-mounted module is supported so as to have a view directly downward toward a trailer hitch ball on a towing vehicle equipped with a backup camera. 
         FIG. 38  is a side elevational view, partly in section, showing a trailer-mounted module of the hitch-alignment facilitating apparatus disclosed herein, together with a mounting device for mating with a trailer hitch coupler to support the trailer-mounted module. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Referring to the drawings which form a part of the disclosure herein, in  FIG. 1  a trailer hitch for a towing vehicle (not shown) includes a short drawbar  16  on which is mounted a trailer hitch ball  18  including a horizontal top surface  19 , as is commonly used in interconnecting towing vehicles with trailers ranging from the smallest in size up to those weighing several thousand pounds. 
     A trailer such as a recreational camping trailer includes a hitch coupler  20  on its tongue  22 . Except for the smallest of trailers, a lift device such as an adjustable jack stand  24  is associated with the tongue, either as a permanent attachment or temporarily mounted on the tongue  22  whenever the trailer is not connected to a towing vehicle. The lift device is used as shown schematically in  FIG. 2  to raise the tongue of the trailer to a great enough height to permit the trailer hitch ball  18  or equivalent portion of the trailer hitch on the towing vehicle to be placed beneath the trailer hitch coupler  20  that is mounted on the tongue  22  of the trailer, as shown in  FIG. 2 . When the coupler  20  mounted on the tongue of the trailer is located directly above the trailer hitch ball  18  on the towing vehicle the lift device  24  may be operated to lower the tongue of the trailer until the coupler  20  moves down to surround and rest upon the hitch ball  18 , allowing the coupler to be fastened to mate the coupler securely with the trailer hitch ball. Once necessary electrical connections (not shown) are made for brakes, turning signals and brake lights, and after safety chains and load leveling levers, (not shown) are connected and adjusted, the lift device  24  can be operated to place the weight of the trailer tongue on the trailer hitch of the towing vehicle. 
     In  FIG. 3  a towing vehicle, for example a pickup truck  26 , is shown in an initial position ahead of a trailer  28 , ready to be backed toward the trailer  28  to permit the hitch coupler  20  on the trailer tongue  22  to be mated with the trailer hitch ball  18  carried on the towing vehicle  26 . 
     As shown in  FIGS. 3 and 4 , a hitch-alignment guidance system as disclosed herein includes in one embodiment a towing vehicle guidance module  30  mounted on the trailer hitch ball  18 , a corresponding towed vehicle module  32  that is mounted on the tongue  22  of the trailer  28 , and a video display device  34  (as shown in  FIG. 9 ) located in view of the operator of the towing vehicle  26 . In the embodiment shown herein, the towing vehicle module  30  is mounted adjustably on the hitch ball  18  of the towing vehicle  26  and thus can be rotated about any axis to place it into the correct alignment with respect to the towing vehicle  26 . The corresponding towed vehicle module  32  may be equipped with a mounting ball  36  similar in size to the trailer hitch ball  18 , and may be attached to the tongue  22  of the trailer by mating the mounting ball  36  with the trailer hitch coupler  20  on the trailer tongue  22 . The mounting ball  36  may be made of a suitable metal or plastics material, with a plastics resin being preferred because of its lower cost and weight. When so mounted, the towed vehicle module  32  is also adjustable about any axis to align it for use of the apparatus disclosed herein to guide the towing vehicle  26  into position to mate the coupler  20  with the hitch ball  18 . 
     Referring now also to  FIG. 5 , the towing vehicle module  30  may have a housing or case that can be folded about a hinge  42  into a compact configuration comparable in size to a telephone handset. The towing vehicle module may also be separable into two separate portions, by removal of an upper portion  44  from a generally horizontal base portion  46  so that the upper portion  44  can be used separately, as will be explained presently. A quick disconnect multi-conductor junction  48  is provided to permit the upper portion  44  of the towing vehicle module  30  to be folded about the hinge  42  as suggested by the arrow  50  to place the towing vehicle module  30  into its more compact configuration, or to permit the upper portion  44  to be removed from the base portion  46  for separate use. 
     The towing vehicle module  30  is shown mounted on the trailer hitch ball  18 , to which it may be attached removably by a suitably strong magnet  52  housed in the base portion  46 , and an arrangement of feet  54  that rest on the hitch ball  18 , acting as a socket to support the towing vehicle module  30  so that it can be swiveled in any direction about the hitch ball  18 . For use of the towing vehicle module  30  with a different sort of hitch arrangement instead of such a ball-and-socket hitch the towing vehicle module could be attached by using a different arrangement not shown herein but which should permit adjustment in all directions. 
     The base portion  46  of the towing vehicle module  30  includes a hitch alignment indicating light beam projector  56  such as a small laser of the type used in laser pointers, arranged to project a beam  57  of visible light directly upward, that is, in a direction perpendicular to a flat upper surface  58  of the base portion. The projector  56  is located so that when the upper surface  58  of the base portion  46  is horizontal the beam of light from the projector  56  will be directed vertically upwards above the center of the hitch ball  18 . The light beam projector may be arranged to project a cruciform beam  57  upward, or it may project a simple, narrow beam to shine a small spot on a surface. 
     The base portion  46  of the towing vehicle module  30  preferably includes a level  60  to aid in placing the towing vehicle module  30  on the hitch ball  18  so that the upper surface  58  of the base portion  46  is horizontal when the towing vehicle module  30  is mounted and ready for use. Leveling may be accomplished using a single circular level  60  as shown or a pair of small elongate tubular levels oriented perpendicular to each other and aligned with the upper surface  58  of the base portion  46 . The top of the base portion  46  may include a removable transparent plate  62  of strong plastic, and a pair of small lamps  64 , such as upwardly directed LEDs, may be housed within the base portion  46  to provide illumination during nighttime use of the hitching guidance system. 
     A small long distance guidance light beam projector  66 , which may also be a small laser, is mounted at the rear end of the base portion  46  and is arranged to project a beam  68  of light rearwardly from the towing vehicle to serve as a long distance guide and a distance indicator when the towing vehicle module  30  is correctly mounted and adjusted. The position of the light beam projector  66  may be adjustable with respect to the base portion  46  in order to project the beam of light at a selected acute angle  70  above horizontal. The angle  70  may be selected so as to make the beam of light  68  strike the front of the trailer  28  or other vehicle to be towed in a visible position when the towing vehicle  26  is separated from the trailer  28  by a selected distance. Thus in one embodiment of the device the light beam projector  66  may be a low power laser oriented at an angle  70  of 22.5 degrees above horizontal, so that the beam  68  of light will strike the front of a camper trailer, depending on its height, when the towing vehicle  26  is several feet ahead of the hitch mating position in which the trailer  28  can be coupled to the towing vehicle  26 . 
     Mounted on and extending upwardly from the base portion  46 , the upper portion  44  of the towing vehicle module  30  includes an electronic image-forming device such as a video camera  72  arranged to provide an electrical image signal that can be transmitted either wirelessly or by wire, for continuous display on a monitor screen  74  of the video display device  34  located in the operator&#39;s cab of the vehicle where it can be seen conveniently by the vehicle operator. For example, the video camera  72  may be a small digital video camera including a sensing device capable of providing digital video image transmission of suitable definition for display on the monitor screen  74 . A target reticle  76  may be included in the camera so as to be visible in the image transmitted by the camera to the monitor screen  74 , as shown in  FIG. 8 , as an indication of the center of the field of view of the camera. The camera  72  includes a self-leveling lens and automatically focusing arrangement in one embodiment. A connector  78  is provided for a cable  80  for signal transmission and for external power to be provided from the electrical system of the towing vehicle  26  to the towing vehicle module  30 . 
     The upright upper portion  44  of the towing vehicle module  30  may include a level  82  arranged to indicate whether the upper portion  44  is correctly aligned in a vertical orientation when the base portion  46  is mounted with its upper surface  58  horizontal, to insure that the entire towing vehicle module  30  is correctly aligned. 
     A set of hanger receivers  84  may be mounted on the rear side of the upper portion  44 , either alone or accompanied by suction cups  86  so that the upper portion  44  can be mounted in a desired location, as on the rear of a trailer  28 , either by the use of a separate hanger (not shown) or by the suction cups  86 . 
     An upper, or short range guidance, light beam projector  90 , which may also be a small laser pointer light, may be provided near the top of the upper portion  44  of the towing vehicle module  30 , and preferably has a light beam  92  of a different color from the beam  68  of the lower, or long distance guidance light beam projector  66  in the base portion  46  of the towing vehicle module  30 . The short range guidance light beam projector  90  may be arranged to project a beam  92  of light rearward and at an acute angle  94  below the horizontal. For example, in one embodiment, as shown in  FIG. 5 , the short range guidance light beam projector  90  is arranged to direct the light beam  92  at an angle  94  of 45 degrees below the horizontal, to provide an indication of when the towing vehicle  26  is closely approaching the hitch-mating location where it can be coupled to the trailer  28 , as will be explained in greater detail presently. 
     Located below the camera  72  there may be a small lamp  96 , such as an LED, that may be utilized at night to help illuminate the area behind the towing vehicle  26 , and particularly to illuminate the towed vehicle, or trailer-mounted, module  32  as the towing vehicle  26  approaches the trailer  28  or other vehicle that is to be towed. Both the camera  72  and the lamp  96  may be mounted on the face of the upper portion  44 , and both may be covered by a transparent cover  98  that can easily be wiped clean, but which protects the interior components of the upper portion  44  from the weather or water that may be splashed toward the towing vehicle module during its use. Ideally both the towing vehicle module  30  and the towed vehicle module  32  are insulated and waterproof, to withstand use in wet weather. 
     Thus, as may be seen in  FIGS. 3 and 4 , when the towing vehicle module is mounted on the trailer hitch ball, projected light beams  57 ,  68 , and  92  from the three light beam projectors  56 ,  66 , and  90  are coplanar, and the alignment light beam projector  56  is located centrally above the top of the trailer hitch ball  18  and aimed directly upward. 
     Also located adjacent the front face of the upper portion  44  may be a switch, such as a magnetically operated reed switch  100 , which may be actuated as will be explained presently to provide an audible indication when the towing vehicle  26  is nearly in the required position for mating the trailer hitch coupler  20  and hitch ball  18  to each other. 
     A suitable rechargeable electric battery  102  is housed within the upper portion  44  to provide required electrical current for the camera  72 , the lasers or other light beam projectors  56 ,  66 , and  90 , and the lamps  64  and  96  included in the towing vehicle module  30  when power is not available from the cable  80 . A solar cell and an associated recharging circuit may also be provided to maintain a charge in the battery  102 . This can be particularly valuable in case of separate remote use of the upper portion  44 , as will be explained below. Suitable connecting wiring, shown greatly simplified, is provided, and manually operable control switches  104  are mounted in a convenient location on the rear side of the upper portion, and include, for example, respective on-off switches for the long distance and short range light beam projectors  66  and  90 , the hitch alignment light beam projector  56 , the digital camera  72 , and the lamps  64  and  96 . 
     An electronic circuit board  106  may be mounted within the upper portion  44  of the towing vehicle module  30  and may contain circuitry related to wireless transmission of the video camera images to the display device  34  and capable of transmitting a video signal that can be received at distances up to several hundred feet from the upper portion  44 , as well as for a satellite global positioning system receiver and a related locator beacon transmitter optionally included in the upper portion  44  of the towing vehicle mounted module  30 , and other circuitry related to the camera  72 , the light beam projectors  56 ,  66 , and  90 , and the lamps  64  and  96 . 
     The target, or trailer-mounted module  32  includes a body housing  108  and may have a transparent planar front target face  110  including a calibrated graticule  111  or grid of parallel horizontal lines and a vertical center line. The target body housing  108  may include a suitable level  112 , and the orientation of the target body can be adjusted by moving the ball within the trailer hitch coupling  20 , or by adjusting another movably adjustable connector, (not shown), by which the trailer-mounted module  32  may be attached to the trailer tongue  22  or the trailer hitch coupling  20  mounted on the vehicle that is to be towed. The position of the target body housing  108  is adjusted using the level  112 , to place the front target face  110  in a vertical orientation. 
     Located within the target body housing  108  and spaced rearwardly from the front target face  110  is an inclined target plate  114  of transparent material such as a polymethyl methacrylate or a polycarbonate on which a target reticle  116  is inscribed clearly and distinctly enough to be visible to the camera  72  through the front target face  110  when the towing vehicle approaches closely enough to the vehicle  28  that is to be towed. The target reticle  116  is located so as to be centered directly beneath the ball receptacle of the trailer hitch coupler  20  when the housing  108  is level. A front or lower, surface  118  of the inclined target plate  114  may be ground or etched so as to make a beam or spot of light falling upon the surface  118  clearly visible to the camera  72 , as seen through the front target face  110 . A small lamp  120 , such as a small LED, may be used to provide edge illumination of the inclined target plate  114 . The target shape reticle  116  is contrastingly marked on the inclined target plate  114 , so that light from the edge lamp  120  is clearly visible in daylight or at night to allow the digital camera  72  to see the target reticle  116  clearly. 
     The target housing body  108  may be attached to the mounting ball  36  or other support structure by a swivel defining an axis  122  parallel with the front, target face  110 , so that the target body housing  108  may be moved through an angle  124  (see  FIG. 3A ) about the axis  122  of the swivel to direct the front target face  110  toward the towing vehicle  26  while the towing vehicle is being backed into the hitch mating location, as will be described in greater detail presently. For the sake of convenient use and the best results, the swivel axis  122  should extend through the center of the target reticle  116 . 
     Small lamps  126  which may, for example, be LEDs, may provided in the top of the body housing  108  to shine upwardly and illuminate the tongue  20  and adjacent parts of the trailer  28  to assist in making the trailer  28  or other vehicle to be towed easily visible in the field of view of the camera  72  included in the towing vehicle module  30 . 
     A tongue height and directional alignment light beam projector  128 , such as a small low powered laser, is mounted in the target body housing  108  and is located and aimed so as to direct a beam  130  of visible light directly through the front target at a center point  132  appropriately marked on the front target face  110 , as shown in  FIG. 6 . This beam  130  of light is useful, as will be explained more fully presently, in initial preparation for backing the towing vehicle  26  toward the trailer  28  so as to place the towing vehicle in the required hitch-mating position for coupling the trailer hitch. A horizontal central opening  134  may be provided through the inclined target plate  114 , and the projected light beam  130  is directed through that hole. Alternatively, the inclined target plate  114  may be imperforate, and the light beam projector  128  may be located within the housing  108  so that the beam  130  of light, after refraction by the inclined target plate  114 , passes through the center  132  of the target front face  110 . 
     Appropriate electrical batteries  136  are provided within the target body housing  108  to power the lamps  120 ,  126  and the light beam projector  128 , and appropriate switches  138  are provided to control operation of the lamps  120 ,  126  and the light beam projector  128 . 
     A small magnet  140  may be carried in a support such as a small telescoping tubular housing  142  which permits the magnet to extend forward a small distance, such as about 1½ inches, from the target front face  110 . The magnet  140  is located where it is aligned with the location of the magnetic reed switch  100  in the towing vehicle module  30  when the towing vehicle is located in the optimal hitch-mating position for mating the coupler  20  with the hitch ball  18 . 
     As an alternative to holding the ball  36  in the socket of the coupler, the trailer-mounted module  32  may be carried on a retractable and extendable support arm  142  mounted on the trailer tongue  22  as shown in  FIG. 8 . A semicircular yoke  143  holds the trailer mounted module  32  on the arm  142  so that it can be rotated about the swivel axis  122  (add to  FIG. 8 ), with the swivel axis extending through a point about which the trailer hitch coupling on the trailer  28  is rotatable with respect to the towing vehicle  26  when the trailer hitch parts are mated and ready for use. When not in use the towed vehicle module  32  is carried in the retracted position shown in broken line. At least in such an embodiment, the trailer-mounted, or towed vehicle, module  32  should be waterproof, so as to withstand immersion as when carried on a boat trailer during launching or recovery of a boat. 
     As another alternative for mounting the trailer-mounted module  32 , as shown in  FIG. 8A  a slide track  144  may be provided on the trailer tongue to hold the towed vehicle, or trailer-mounted, module  32 . With the trailer-mounted module  32  located as shown in solid line the reticle  116  on the inclined target plate  114  is centered below the coupler  20  for use. The module may be held by a swivel joint  145  so that it can be adjustably pivoted about the axis  122  as explained above. When not in use the module  32  can be withdrawn along the slide track  144  and carried in a retracted position and a front position of the slide track  144  may be telescoped back over the rear part, as shown in broken line in  FIG. 8A , so as not to interfere with the trailer hitch ball  18  and socket  20 . 
     Similarly, a telescoping support slide  146  for the towing vehicle module  30  may be mounted in a specifically provided storage location such as a protective compartment  147  in a rear end portion of the towing vehicle  26 , adjacent the trailer hitch. The towing vehicle module  30  can be supported on the support slide  146 , either retracted into the storage location, or with the slide  146  extended to a position in which the towing vehicle module  30  is located directly above the hitch ball  18 . In the extended position as shown in solid line in  FIG. 8A , the towing vehicle module  30  is used in the same manner as when mounted on the hitch ball  18  as shown in  FIGS. 2-5 . 
     The towed vehicle, or trailer-mounted, module  32  may be mounted as shown in  FIGS. 8 and 8A  as original equipment, or as after-market equipment. The towing vehicle module  30  may also be mounted as shown in  FIG. 8A  as original equipment, or as an option for towing vehicles in which a rear end structure may include or may be modified easily to include a storage compartment  147 . 
     The video display device  34  may be mounted as seen in  FIG. 9 , on the dashboard of the pickup truck or other towing vehicle  26 , either as added equipment, or built into the dash of the towing vehicle  26  as original equipment, in which case it may be designed for multiple uses such as to display GPS mapping systems or other vehicle operational information of interest, as well as being electrically connected so that the monitor screen  74  is available additionally for use in connection with the hitch-alignment facilitating apparatus disclosed herein. It could also be built to interface with existing original equipment dash-mounted displays, portable monitors, laptop computers, or portable GPS and mobile telephone display units. 
     As shown in  FIG. 9  the monitor screen  74  displays an image of the trailer  28  as seen by the camera  72  when the towing vehicle module  30  is properly mounted and adjusted, and with the towing vehicle  26  in position ahead of the trailer  28 , ready to begin backing toward the trailer. The transparent front target face  110  of the trailer mounted, or target, module  32  is clearly visible, and the target reticle  116  on the inclined target plate  114  is also visible through the transparent front target face  110 . Additionally, the reticle  76  in the camera  72  is also visible in the monitor screen  74 , as are the light beam, or spot,  68  which may be of a first color, for example red, projected from the lower or long distance guidance light beam projector  66  of the base portion  46  of the towing vehicle module  30  and another light beam, or spot,  92 , which may optionally be of a second color such as green, projected by the upper, or short range guide light beam projector  90  carried in the upper portion  44  of the towing vehicle module  30 . In addition to or instead of a small spot the light beams  68  and  92  may be projected as horizontal lines by the projector. 
     Trailer Hitching Procedure 
     In order to utilize the hitch alignment facilitating system described above for placing the towing vehicle  26  in the correct location for mating the hitch coupler  20  on the trailer tongue  22  to the trailer hitch ball  18  on the towing vehicle  26 , the target, or trailer-mounted, module  32  is attached to the coupler  20  on the tongue  22  of the trailer  28  or other vehicle that is to be towed, and the towing vehicle module  30  is mounted on the trailer hitch ball  18  of the towing vehicle, as described and illustrated above. When the trailer-mounted module  32  is level the swivel axis  122  is vertical, and the body or housing  108  is rotated about the swivel axis  122  until at an angle  124  the beam  130  of light from the light beam projector  128  is directed toward the towing vehicle module  30 , as shown in  FIGS. 3 ,  3 A, and  4 . If both the towing vehicle  26  and the vehicle  28  that is to be towed are on flat, level ground, the trailer tongue lift  24  can then be operated to bring the tongue  22  of the trailer  28  to a height at which the beam  130  of light projected from the light projector  128  is directed toward the lens of the camera  72  in the towing vehicle module  30 . This will place the trailer hitch coupler  20  at a preferred height to provide clearance for the base portion  46  of the towing vehicle module  30  to pass beneath the trailer-mounted module  32  of the hitch-guiding apparatus as the towing vehicle  26  is backed into the hitch-mating position. Once the height of the trailer tongue  22  has been adjusted the height guidance light beam  130  can be turned off by the appropriate switch  138 . 
     With the towing vehicle module mounted and level as described above, the central axis of the field of view and the reticle  76  of the camera  72  should be aimed directly rearwardly, as indicated by the right angle  152  in the horizontal plane, shown in  FIG. 3 , and the laser or other light beams  68  and  92  from the guidance beam projectors  66  and  90  are then also directed rearwardly. The video camera  72  is then turned on, and its view is displayed as an image on the monitor screen  74  in the towing vehicle, in view of the vehicle operator, as shown in  FIG. 9 . The towing vehicle  28  is then moved backward toward the tongue  22  of the trailer, which is clearly shown on the monitor screen  74 . As the towing vehicle  26  approaches the trailer  28  the towing vehicle  26  should be steered carefully to keep the target or towed vehicle module  32  centered in the image of the camera reticle  76  rather than to one side as shown in broken line. The light beam  68  from the long distance guidance light beam projector  66  will be visible where it impinges on the front of the trailer  28 , once the towing vehicle is within several feet from the required position for connection of the trailer hitch coupler  20  to the trailer hitch ball  18 . The distance where the light beam  68  can be observed is determined by the angle  70  at which the long distance guidance beam is oriented above horizontal, the length of the trailer tongue  22 , and the height of a front surface of the trailer  28  on which the light beam  68  can fall. 
     As the towing vehicle  26  is backed closer toward the required hitch mating location, the long distance guidance light beam  68  will move downward along the front of the trailer, while the image of the front target face  110  on the front of the towed vehicle module  32  will grow larger in the monitor screen  74  as the camera  72  moves closer to it, as shown in  FIG. 10 . If the trailer and the towing vehicle are on anything other than flat level ground, it is desirable, when the towing vehicle  26  and the trailer  28  are separated by no more than a few feet, to confirm that the trailer tongue  22  is at the required height relative to the trailer hitch ball  18  on the towing vehicle, as by again operating the height adjustment light beam projector  128  and, if necessary, adjusting the lift  24  supporting the trailer tongue  22  so that the height adjustment light beam  130  is directed toward the lens of the camera  72 . 
     The laser beam  68  from the long range guidance beam projector will impinge on the trailer at a location that appears to be vertically above the target front face  110 , and as the towing vehicle module  30  approaches closer to the trailer mounted module  32  the long distance guidance light beam will become visible on the target front face  110  when the hitch ball  18  is several inches from the coupler  20 , as shown in  FIG. 11 . 
     As the towing vehicle  26  is moved further backwards toward the trailer  28 , with the target center  132  on the target front face  110  of the towed vehicle module  32  kept centered within the camera lens reticle  76 , the upwardly inclined light beam  68  of the long distance guidance light beam projector  66  will strike the top of the front target calibrated graticule  111 , indicating that the towing vehicle is closely approaching the hitch mating location. If the trailer hitch coupler  20  is adjusted correctly in height the horizontal lines of the graticule  111  will give an accurate indication of the distance through which the towing vehicle  26  still needs to move rearwardly to the desired hitch-mating position. The beam  68  will move downward along the front target face  110  as the base portion  46  of the towing vehicle module  30  approaches the front target face  110  until the lower light beam  68  progresses down to the bottom of the front target face  110  just before the base portion  46  of the towing vehicle module  30  passes beneath the target face  110 . It should be apparent to the towing vehicle operator viewing the monitor screen  74  if the height of the trailer tongue is not correct, as the center  132  of the front target face  110  will appear to be too high in the lens reticle  76  of the camera  72  if the trailer tongue  22  is too high, or will appear too low in the lens reticle  76  field of view of the camera  72  if the trailer tongue  22  is too low. If such misalignment appears then the operator should stop backing toward the trailer  28  and adjust the height of the trailer tongue  22  to be sure that the towing vehicle hitch ball will be able to pass properly beneath the tongue of the trailer, and that the base portion  46  of the towing vehicle module  30  can pass beneath the target, or towed vehicle module  30 . 
     Once the upwardly inclined long distance guidance laser beam approaches the bottom of the front target plate the downwardly inclined light beam  92  from the short range guidance light beam projector  90  at the top of the upper part  44  of the towing vehicle module  30  should become visible at the bottom of the front target face  110  if the trailer tongue  22  is at the correct height with respect to the trailer hitch ball  18  on the towing vehicle. When the green laser beam  92  of the upper laser light beam projector  90  is visible on the front target calibrated graticule  111  the towing vehicle  26  is very close, within about two inches, to the desired hitch-mating location. The light beam  57  from upwardly directed hitch alignment light beam projector  56  in the base portion  46  of the towing vehicle module  30  should then be visible to the camera  72  at the top of the inclined target plate  114  within the towed vehicle module  32 , as shown in broken line in  FIG. 7 . At about that distance the magnet  140  may activate the reed switch  100  causing an audible signal to be sounded by the display device  34 . 
     As the towing vehicle  26  is backed further the laser beam  57  will appear to move down across the target reticle  116  defined on the inclined etched target plate  114 , until, when the towing vehicle is in the correct position, as shown in  FIG. 12  the laser beam  57  will appear to be centered in the target on the inclined etched target plate. The towing vehicle operator should then stop the towing vehicle  26 , set its brakes, and then remove both modules  30  and  32  of the hitch guidance apparatus from their respective places on the towing vehicle trailer hitch ball  18  and the trailer hitch coupler  20  and then lower the trailer tongue  22  to mate the coupler  20  with the trailer hitch ball  18 . 
     Additional Functionality 
     While the principal utility of the apparatus described above is in enhancing the ability to back a towing vehicle  26  easily and accurately to a mating location where a trailer hitch can be coupled, the ability to transmit a video image wirelessly from the camera  72  to the monitor screen  74  near the towing vehicle driver&#39;s position makes the upper portion  44  of the towing vehicle module  30  otherwise conveniently useful, both in connection with backing the trailer  28  and while towing the trailer  28  along a highway. Since the upper portion  44  of the towing vehicle module  30  can be removed from the base portion  46  by use of the quick disconnect coupling  48 , the upper part  44  can be mounted on the rear of the trailer  28 , as shown in  FIG. 13 , either by use of the suction cups  86  or by the use of an appropriate hanger (not shown) and the hanger receivers  84 . Video images from the camera  72  can then be transmitted wirelessly to the display device  34  in the towing vehicle  26 , so that the driver of the towing vehicle can see what is behind the trailer  28  as the trailer is backed into a parking position, making it much easier to park the trailer safely. Additionally, the camera  72 , when mounted on the back of the trailer  28 , can be used while towing the trailer along a highway, to provide a much better view of vehicles following the trailer  28  than is normally available simply by using ordinary side view mirrors on the towing vehicle  26 . 
     Within a limited distance from the towing vehicle, the camera  72  can be used by a person carrying the unit to transmit a view to the video display device  34  in the towing vehicle  26 . A suitable wireless receiver and antenna, capable of receiving the transmitted signal from the towing vehicle module and providing both audio and video output signals to the monitor, may be connected with the monitor. 
     Optionally, the towing vehicle module  30  can include a Global Positioning System (GPS) satellite unit and a beacon transmitter  148  contained in the upper portion  44 , as shown in simplified form in  FIG. 5 . The GPS navigation system may be designed to communicate with commercially available satellite radio and mapping services. The GPS unit included in the upper portion  44  can thus be carried by a person venturing away from the location of the towing vehicle  26 , as when the towing vehicle  26  is left in a camp and a person hikes into nearby wilderness, where the beacon transmitter, coupled with the GPS unit in the upper portion  44 , is available as an emergency beacon transmitting its location in case the user is injured or becomes disoriented. 
     In connection with use of the GPS beacon, a separate handheld mobile telephone and beacon monitor unit  150 , such as that shown in  FIG. 14 , may be used to determine and display the location of a person carrying the upper part of the towing vehicle module. This acts as a safety feature in conjunction with use of the upper portion  44  of the towing vehicle module  30 , which, in one embodiment of the device, may include a low power radio telephone able to conduct two-way communications with such a separate self-contained handheld unit  150 . Alternatively, the handheld unit  150  may include circuitry capable of utilizing existing cellular or satellite mobile telephone or wireless computer communications systems to receive and display the GPS beacon data showing the location  154  of the upper portion  44  of the towing vehicle module  30  carried by a person at some distance from the towing vehicle in which the video display device  34  is installed and operated. The beacon monitor unit could thus be used with appropriate identifying codes to locate the upper portion  44  either locally or at great distances, depending on the associated communication system used. 
     The monitor screen  74  of the display device  34  in the towing vehicle  26  may be equipped and programmed with a touch screen control interface for use in connection with programming a GPS navigation system setting to synchronize the display device  34  and the upper portion  44  of the towing vehicle module  30  with a satellite navigation system in connection with monitoring the location of the portable upper portion  44  of the towing vehicle module  30 . 
     As an optional accessory, a portable, wearable visual display may be provided by a wearable display device  156  similar to a pair of virtual reality glasses known for use in connection with video computer gaming technology. One or two video display devices  34  may be provided in the wearable display device  156  for use instead of or as well as the dash-mounted video monitor screen  74 , to provide an image from the video camera  72  to the operator of the towing vehicle  26 , while the towing vehicle is backed into position for mating the trailer  28  to the towing vehicle  26 . 
     ADDITIONAL EMBODIMENTS 
     Another embodiment of the hitch alignment guidance system is shown in  FIGS. 16-27 . As shown in  FIG. 16 , a recreational camping trailer  28  includes a hitch coupler  20  on its tongue  22 , and a towing vehicle drawbar  16  has a trailer hitch ball  18 ′ that is to be mated with the trailer hitch coupler  20 . A towing vehicle module or unit  160  mounted on the hitch ball  18 ′ cooperates with a towed vehicle module or unit  162 , which may also be called a trailer-mounted module, or a trailer unit, held by the coupler  20  to guide an operator of the towing vehicle  26  to bring the trailer hitch ball  18 ′ on the towing vehicle  26  to a hitch-mating position directly beneath the coupler  20  mounted on the tongue  22  of the trailer. A video display device or monitor  164  (shown in  FIG. 27 ) is located in view of the operator of the towing vehicle  26 . 
     In  FIG. 16  the towing vehicle  26 , for example a pickup truck, is shown in an initial position ahead of the trailer  28 , ready to be backed toward the trailer  28  to permit the hitch coupler  20  on the trailer tongue  22  to be mated with the trailer hitch ball  18 ′ carried on the towing vehicle  26 . 
     The towing vehicle module  160  is mounted adjustably on the hitch ball  18 ′ of the towing vehicle  26 , resting on the flat horizontal top surface  19  (shown in  FIG. 19 ), and can be rotated about a vertical hitch pivot axis  165  normal to the surface  19 , to align the towing vehicle module  160  to face directly rearward from the towing vehicle  26 . 
     The corresponding towed vehicle module  162  may be equipped with a mounting ball  166  similar in size to the trailer hitch ball  18 , and may be attached to the tongue  22  of the trailer by using the trailer hitch coupler  20  on the trailer tongue  22  to engage the mounting ball  166 . The mounting ball  166  may be made of a suitable metal or plastics material, with a plastics resin being preferred because of its low cost and light weight. When so mounted, the towed vehicle module  162  is also adjustable, as will be explained in greater detail below, to align it for use of the apparatus disclosed herein to guide the towing vehicle  26  into position to mate the coupler  20  with the hitch ball  18 ′. 
     Referring now also to  FIG. 19 , the towing vehicle module  160  may have a housing or case  168  including a lower, or base, portion  170  located above the hitch ball  18 ′, and an upper portion  172  that may include one or more laser modules, as well as a video camera  180 . 
     The towing vehicle module  160  may be attached removably to the trailer hitch ball  18 ′ by a suitably strong magnet  182 . The magnet  182  may be of an annular shape and may be included in an adaptor  184  defining a shallow socket of a size to fit snugly against the outside of the ball  18 ′. The adaptor  184  is attached to the base portion  170  as by magnetic attraction and acts to hold the towing vehicle module  160  on the flat top surface  19  of the hitch ball  18 ′ so that it can be swiveled to any direction about the axis  165 . The adaptor  184  may have depressions  185  or annular grooves in its upper face to receive a projection such as a screw head  187  of a screw attaching a cover plate to the bottom of the lower portion  170 , to locate the adaptor  184  correctly on the towing vehicle unit  160 . For use of the towing vehicle module  160  with a different sort of towing vehicle hitch part instead of the ball  18 ′ the towing vehicle module  160  could be attached by using a different adaptor not shown herein, but which should permit directional adjustment about a vertical hitch pivot axis  165  while maintaining a constant horizontal attitude. 
     The base portion  170  of the towing vehicle module  160  may include a light beam projector  186  such as a small laser module arranged to project a hitch alignment beam  188  of visible light directly upward above the hitch ball  18 ′, in a direction perpendicular to the horizontal upper surface  19  of the hitch ball  18 ′. As shown best in  FIGS. 16 and 19 , the light beam projector  186  may be located in the base portion  170  so that it projects its beam of light horizontally onto a reflective surface such as a prism (not shown) or a mirror  190  located in the base portion  170  of the towing vehicle unit  160 , so that the beam of light  188  will be directed vertically upwards above the center of the hitch ball  18 ′. The light beam projector  186  may be arranged to project a cruciform scanning beam  188  upward, along the pivot axis  165  defined by the center of the hitch ball  18 ′, or it may project a scanning beam oriented as shown in  FIG. 21 , to project a horizontal line, or it may project a simple pinpoint beam to shine a small spot onto the surface of the mirror  190 . With the laser module of the light beam projector  186  oriented horizontally in the base portion  170  and directed rearwardly, a reflective surface of the mirror  190  at a 45-degree angle as shown in  FIG. 19  will reflect the beam  188  upward, yet the lower or base portion  170  of the housing  168  may be constructed with a low profile to minimize the height by which the tongue  22  has to be raised to give ample clearance for use of the hitch alignment guidance system. 
     A long distance directional guidance light beam projector  192 , which may also be a small laser module, is mounted at the rear end  194  of the base portion  170  and is arranged to project a beam  196  of light rearwardly from the towing vehicle  26  to serve as a long distance guide and a directional indicator for the towing vehicle operator when the towing vehicle module  160  is correctly mounted and adjusted. The long distance light beam projector  192  may be a line-generating laser module oriented to project a vertical line and thus scan in a vertical plane located centrally and oriented longitudinally with respect to the base portion  170 , in order to project the beam of light  196  rearwardly, scanning within a selected acute angle  198  that must extend above the horizontal. Thus, in one embodiment of the towing vehicle module  160  the light beam projector  192  may be a low power line-generating laser module scanning through an angle  198  of 110 degrees centered on or above the horizontal, so that the beam  196  of light will strike the front of the trailer  28  when the towing vehicle  26  is separated from the trailer  28  by a selected distance such as several feet ahead of the hitch-mating position in which the trailer  28  can be coupled to the towing vehicle  26 . When the towing vehicle approaches closer to the hitch-mating position the long distance light beam  196  should still fall on the towed vehicle module or trailer mounted module  162  of the apparatus described herein. 
     Extending upwardly from the front end of the base portion  170 , the upper portion  172  of the towing vehicle module  160  includes an image-forming device such as the digital video camera  180  mounted to view rearwardly from the rear face  202  of the upper portion  172 . The video camera  180  is arranged to transmit an electrical image signal, either wirelessly or by wire, for continuous display on a monitor screen  204  of the video display device  164 , shown in  FIG. 27 , located in the operator&#39;s cab of the vehicle  26 , where it can be seen conveniently by the vehicle operator. The camera  180  should have good low-light sensitivity, must be able to focus at a very close range, and should be able to form color images with suitable image resolution. One such waterproof video camera is available from the Top Well International Electric company of Guangdong, China as its model T-600 camera capable of 720(H)×576(V) PAL resolution and having a lens with a 170-degree field of view. A target tracking capability may be included in the camera  180  so that it can automatically focus on the trailer mounted unit  162  and form an image to be transmitted to the monitor screen  204 , as shown in  FIG. 27 . Ideally a reticle  205  is displayed as part of the camera image to frame what the camera is focused on. 
     Located below the camera  180  in the upper portion  172  there may also be a close range center light beam projector  226  such as a line-generating laser module located to project a beam  228  scanning in a central, rearwardly and vertically aligned plane that also includes the hitch pivot axis  165  and coincides with the plane of the scanned beam  196  of the long distance directional guidance light beam projector  192 , to fall on the towed vehicle or trailer-mounted module  162  as the towing vehicle  26  closely approaches the trailer  28 . 
     A connector  206  (shown only schematically) may be provided for a cable for signal transmission and for provision of electrical power from the electrical system of the towing vehicle  26  to the towing vehicle module  160 . A suitable rechargeable electric battery  210  may be housed within the housing  168  to provide required electrical power for the camera  180  and the lasers or other light beam projectors  186 ,  192 , and  226  included in the towing vehicle module  160  when power is not available from a cable  208 . 
     Suitable connecting wiring, not shown, is provided, and manually operable control switches such as a pushbutton switch  234  with a weather tight cover may be mounted in convenient locations on the upper portion  172 , and may include, for example, a main on-off switch and respective on-off switches for the main hitch alignment, long distance, and close range center light beam projectors  186 ,  192 , and  226 . An electronic circuit module  240  may be mounted within the upper portion  172  of the towing vehicle module  160  and may contain circuitry providing for wireless transmission of images from the video camera  180  to the display device  205 . For example a suitable 2.4 GHz wireless video transmitter operable on a 12V. power supply is available from Top Well International Electric company of Guangdong, China. An antenna  242  for the transmitter may be located on the towing vehicle module  160 . 
     The target, or towed vehicle mounted module  162  shown in FIGS.  19  and  23 - 26  includes a body  244  that may have an inclined planar front target face  246  including a graticule  248  with visible indicia such as concentric loops  250  and pairs of parallel horizontal lines  254  and vertical lines  256  intersecting at the center  258  of the loops. The target body  244  may include a suitable level  260  on at least one side, and the orientation of the target body can be adjusted by moving the ball  166  within the trailer hitch coupling  20 , or by adjusting another movably adjustable connector, such as a magnetically joined swivel  264 , by which the body  244  may be attached to the ball  166 . The position of the target body  244  may be adjusted using the level or levels  260  to place the front target face  246  in a preferred location and orientation. As shown in  FIGS. 18 and 19 , the center  258  of the target face  246  should be directly beneath the center of the ball receptacle of the coupler  20  when the body  244  is level, and the target face  246  may be inclined to face forward and downward at for example, 45 degrees to the horizontal. 
     The inclined target face  246  may be a plate of a transparent plastics material such as Plexiglas on which the graticule  248  is displayed clearly and distinctly enough to be seen clearly in an image transmitted by the camera  180  as the towing vehicle  26 , with the towing vehicle module  160  mounted on the hitch ball  18 ′, backs toward the vehicle  28  that is to be towed. For example the graticule may be engraved in the face  246 , or an adhesively attached printed cover may be of material such as a prismatic remote sensing target reflector material  3000 X of flexible synthetic resin sheet material with adhesive backing is, available from the 3M Company of St. Paul, Minn. Alternatively, a thin sheet metal cover cut to include slits defining the loops  250  and  252  and the lines  254  and  256  may be attached to a sheet of translucent plastic material of the target face  246 . An outer surface  262  of the inclined target face  246  may be molded, ground or etched so as to make a beam or spot of light falling on the surface  262  clearly visible to the camera  180 . A small lamp  263 , such as a small LED, may be used to illuminate the inclined target face  246  from its edge to make the loops  250  and lines  254 ,  256  clearly visible. The loops  250  may be elliptical, to appear as circles in images generated by the camera  180  as the towing vehicle  26  approaches the trailer  28 . The target graticule  248  should in any case be marked contrastingly on the inclined target face  246 , so as to be clearly visible in daylight and at night, to allow the camera  180  to form a clear image of the target graticule  248 . 
     The swivel  264  may define an axis  266  extending through the center  258  of the target face  246  and the center of a ball held in the coupler  20 , so that the body  244  of the towed vehicle or trailer unit  162  may be turned, as through an angle  268  (see  FIG. 20 ) about the axis  266  of the swivel, to direct the target face  246  toward the towing vehicle  26  while the towing vehicle is being backed into the hitch-mating location, since the towing vehicle  26  may initially not be directly ahead of the towed vehicle  28 . To permit the trailer unit or target body  244  to be dislodged, rather than be crushed, if the towing vehicle or the towing vehicle module  160  accidentally collides with the trailer unit  162 , the mounting ball  166  may be made of magnetic material or include an insert  270  of magnetic material, and the body  244  may have a suitably strong magnet  272  to attach the body  244  to the ball  166 . The magnetic insert  270  may be flush with the base of the ball  166 , as shown, and the magnet  272  may be circular or annular and mounted in a corresponding boss on the top of the body  244  to attract and hold the magnetic insert  270 . A screw  274  may extend through the magnetic insert  270  into the ball  166 , with a projecting head to fit in a depression centered in the magnet  272  to form the swivel joint  264  defining the axis  266 . 
     A tongue height and directional alignment light beam projector  280 , such as a small low powered laser module, may be mounted in the target body  244  and located and aimed so as to direct a pinpoint beam  282  of visible light forward through the center  258  of the target face  246 . This beam  282  of light is useful in initial preparation for backing the towing vehicle  26  toward the trailer  28  or other vehicle that is to be towed. An opening may be provided through the center  258  of the inclined planar face  246 , and the projected light beam  282  may be directed through that opening. Alternatively, the inclined face  246  may be imperforate, with its center  258  transparent, and the light beam projector  280  may be located within the trailer unit body  244  so that the beam  282  of light, after refraction through the inclined target face  246 , exits forward from the center  258  of the target front face  246  in a direction that is horizontal when the trailer unit body  244  is level as mentioned above. 
     Appropriate electrical batteries  284  may be provided within the trailer unit body  244  to power the lamps  263  and the light beam projector  280 , and appropriate switches  286  are provided to control the circuits. 
     As shown in  FIG. 27 , the video monitor screen  204  displays an image of the trailer  28  as seen by the camera  180  when the towing vehicle module  160  is properly mounted and adjusted, and with the towing vehicle  26  in position ahead of the trailer  28 , ready to begin backing toward the trailer, but not yet directed precisely toward the trailer  28 . The planar front target face  246  of the trailer unit, or target module  162  is clearly visible in the displayed image, and the target graticule  248  on the inclined front target face  246  is also visible on the monitor screen  204 . Additionally, the reticle  205  of the camera  180  may also be visible in the monitor screen  204 , as is the projected line of the long distance beam  196 , which may be of a first color, for example green, shown projected from the lower or long distance guidance light beam projector  192 , onto parts of the trailer  28 . Another projected beam,  228  which may optionally be a scanned line of a second color such as red, projected by the center light beam projector  226  carried in the upper portion  172  of the towing vehicle module  160 , may also be visible on the trailer  28 . 
     A suitable video monitor  164  is available from, for example, the Top Well International Electric company of Guangdong, China, as its model 7109, with a 7-inch diagonal LCD screen with resolution of 480×342 and equipped to receive a 2.4 GHz signal. The system may be operated to utilize a wired cable connection between the towing vehicle module and the video monitor  160  or an installed original equipment video monitor in the towing vehicle  26 . Alternatively, the wireless transmitter  240  may be used, together with the antenna  242  and a suitable antenna (not shown) connected to the video monitor  160 , either so it can be placed on the exterior of the towing vehicle  26  near the operator&#39;s position, or connected through an installed cable to a location near the drawbar  16 . 
     In order to utilize the hitch alignment facilitating system as described above and shown in  FIGS. 16-29  for placing the towing vehicle  26  in the correct location for mating the hitch coupler  20  on the trailer tongue  22  to the trailer hitch ball  18 ′ on the towing vehicle  26 , the target, or trailer unit  162  is attached to the coupler  20  on the tongue  22  of the trailer  28  or other vehicle that is to be towed, and the towing vehicle module  160  is mounted on the trailer hitch ball  18  of the towing vehicle, as described above. When the trailer unit  162  is level the swivel axis  266  is vertical, and the body or housing  244  may be rotated about the swivel axis  266  until at an angle  124  the beam  282  of light from the light beam projector  280  is directed toward the towing vehicle module  160 , as shown in  FIGS. 16 and 18 . If both the towing vehicle  26  and the vehicle  28  that is to be towed are on flat, level ground, the trailer tongue lift  24  can then be operated to bring the tongue  22  of the trailer  28  to a height at which with the body  244  kept level the beam  282  of light projected from the light projector  280  is directed toward the lens of the camera  180  in the towing vehicle module  160 , as shown in  FIG. 16 . This will place the trailer hitch coupler  20  at a preferred height to provide clearance for the base portion  170  of the towing vehicle module  160  to pass beneath the trailer unit  162  of the hitch-alignment guidance system as the towing vehicle  26  is backed into the hitch-mating position. Once the height of the trailer tongue  22  has been adjusted the light beam projector  280  can be turned off by the switch  286 . 
     With the towing vehicle module  162  mounted and its body  244  level as described above, the central axis of the field of view and the reticle  205  of the camera  180  should be aimed directly rearwardly from the towing vehicle  26  as shown in  FIG. 16 , so that the laser or other light beams  196  and  228  from the guidance beam projectors  192  and  226  are then also directed rearwardly. The video camera  180  is then turned on and its detected view is displayed as an image in view of the vehicle operator, on the monitor screen  204  in the towing vehicle  26 , as shown in  FIG. 27 . The towing vehicle  26  is then moved backward toward the tongue  22  of the trailer, which can be clearly seen on the monitor screen  204 . As the towing vehicle  26  approaches the trailer  28  the towing vehicle  26  should be steered carefully, by observing the video image from the camera  180  in the monitor screen  204 , to keep the target face  246  centered in the image displayed on the monitor screen  204 . The scanned light beam  196  from the long distance guidance light beam projector  192 , impinging as a line on the front of the trailer  28 , will be visible on the monitor screen  204  as shown in  FIG. 27 , once the towing vehicle is within several feet from the required position for connection of the trailer hitch coupler  20  to the trailer hitch ball  18 . 
     As the towing vehicle  26  is backed closer toward the required hitch mating location, the long distance directional guidance light beam  196  will become discernable on the image of the inclined front target face  246 , and the front of the towed vehicle module  162  will appear larger in the monitor screen  204  as the camera  180  moves closer to it, as shown in  FIG. 28 . Once the projected scanned line  196  from the long distance guidance light beam projector  192  is visible on the front target face  246 , the towing vehicle  26  should be steered to keep the scanned line  196  centered on the graticule  248  as shown in  FIG. 28 . Especially if the trailer  28  and the towing vehicle  26  are on anything other than flat level ground, it is desirable, when the towing vehicle  26  and the trailer  28  are separated by a few feet, to confirm that the trailer tongue  22  is at the required height relative to the trailer hitch ball  18  on the towing vehicle  26 , as by again operating the light beam projector  280  and, if necessary, adjusting the lift  24  supporting the trailer tongue  22  so that the height adjustment light beam  282  is directed toward the lens of the camera  180 . 
     It should also be apparent to the towing vehicle operator viewing the monitor screen  204  if the height of the trailer tongue  22  is not correct, as the center  258  of the front target face  246  will appear to be too high in the transmitted image from the camera  180  if the trailer tongue  22  is too high, or will appear too low in the image from the camera  180  in the monitor screen  204  if the trailer tongue  22  is too low. If such misalignment appears then the operator should stop backing the towing vehicle  26  toward the trailer  28  and adjust the height of the trailer tongue  22  to be sure that the base portion  170  of the towing vehicle module  160  can pass beneath the towed vehicle module  162 . 
     As the towing vehicle  26  is moved further backwards toward the trailer  28 , the long distance directional guidance light beam  196  will appear to move downward and then disappear from view on the graticule  248  as the base portion  170  of the towing vehicle module  160  moves beneath the inclined target front face  246 . The light beam  228  of the centrally located light beam projector  226  should then still be already visible as a vertical line on graticule  248 , ideally in a color contrasting with the color of the long distance beam  196 , indicating that the towing vehicle  26  is very closely approaching the hitch-mating location. The towing vehicle should then be backed very slowly, and the main hitch alignment beam  188  will become visible as a horizontal line and move downward from the top of the inclined front target face  246 . As the base portion  170  of the towing vehicle module  160  moves further backward beneath the target face  246 , the hitch alignment light beam  188  will appear to move down across the target graticule  248  defined on the inclined target planar face  246 , until, when the towing vehicle is in the correct hitch-mating position as shown in  FIG. 29 , the horizontal line of the hitch alignment light beam  188  and the vertical line of the light beam  228  will appear as a cross in the center  258  of the target on the inclined target plate  246 . The towing vehicle operator should then stop the towing vehicle  26 , set its brakes, and then remove both modules  160  and  162  of the hitch alignment guidance system from their respective places on the towing vehicle trailer hitch ball  18 ′ and the trailer hitch coupler  20 . The trailer tongue  22  can then be lowered to mate the coupler  20  with the trailer hitch ball  18 ′. 
     In one somewhat different embodiment of the hitch alignment guidance system shown in  FIGS. 30-34 , a towing vehicle module  288  is generally similar to the towing vehicle module  160 , but its upper portion  172 , instead of a light beam projector  226 , includes at least one and preferably a pair of “triangulation” light beam projectors  290  and  292 . These may also be small laser line generator modules, mounted to scan in vertical scanning planes  294  and  296  and thus to project vertical lines on vertical surfaces. The light beam projectors  290  and  292  may be located on respective opposite lateral side portions of the rear face  202  of the upper portion  172  and may be directed rearward and obliquely laterally inwardly angled. In one embodiment the laser modules  290  and  292  are located so that the vertical scanning plane  294  intersects the vertical scanning plane  296  along a line of intersection  298  extending directly upward along the pivot axis  165  above the center of the hitch ball  18 ′ when the towing vehicle unit  288  is mounted on the hitch ball  18 ′. To avoid confusion, the laser modules  290  and  292  may project beams of a color contrasting with the color projected by the long distance beam projector  192 . 
     Referring next to  FIGS. 32 ,  33 , and  34 , when the towing vehicle  26  is several feet away from the trailer  28  and backing directly toward the tongue  22  of the trailer  28 , the vertical line light beam projection  196  from the long distance beam projector  192  falls on the inclined front face  246  and is centered on the graticule  248  as shown in  FIG. 32 . Assuming that the surfaces of the front of the trailer  28  are planar and vertical, the projected beams  294  and  296  will be visible as vertical lines projected on the front of the trailer  28  as shown in  FIG. 32 . 
     When the towing vehicle  26  has been moved closer to the trailer  28  than is shown in  FIGS. 31 and 32 , the beam  196  projected from the long distance beam projector  192  will be interrupted by the tongue  22  and no longer be visible on the upper portion of the trailer, as shown in  FIG. 33 . Portions of the projected beams  294  and  296  will remain visible on vertical front surfaces of the body of the trailer  28  until they are also interrupted by and become visible on the structure of the tongue  22 . As the towing vehicle  26  backs further, the projected beams  294  and  296  will become visible as diagonal lines on the surface of the inclined planar target face  246 , first at the upper corners of the target face  246  as shown in  FIG. 23 , as a result of the orientation of the target face at an angle of 45 degrees with respect to the vertical. So long as the towing vehicle  26  is directed accurately toward the towed vehicle module  162  and the body  244  has been turned to face directly toward the towing vehicle module  288 , the projected beams  294  and  296  will be symmetrically oppositely located. As the towing vehicle backs further toward the trailer  28  the beams  294  and  296  will move diagonally downwardly across the target face  246  toward the center  258 . 
     As the towing vehicle  26  backs even closer to the hitch mating position and the rear end  194  of the towing vehicle module  288  moves beneath the towed vehicle module  162 , the beam  196  will be obscured. At the same time the diagonal beams  294  and  296  will be seen to move closer to the center  258  of the target face  246  and the horizontal line of the upwardly directed laser beam  188  will appear at the top of the target face  246  and move down toward the center  258  as the towing vehicle is backed very slowly through the final inches. When the towing vehicle  26  reaches the hitch mating position the diagonal beams  294  and  296  and the horizontal beam  188  will all intersect at the center  258  and the target face  246  will appear large in size on the video monitor screen  204 , as shown in  FIG. 34 . 
     In yet another embodiment of the hitch alignment guidance system a towing vehicle module  302  shown in  FIG. 35  differs from the towing vehicle modules  160  and  288  in that there is no light beam projector  186  nor a light beam  188  projected directly upward along the hitch pivot axis  165 . Instead, there are left and right triangulation lasers  290  and  292  that project beams  294  and  296  scanning in intersecting vertical planes as in the towed vehicle module  288  described above, and a centrally located light beam projector  304 , which may also be a line projecting laser beam module, projects a light beam  306  directed rearward along a vertical central plane that is coincident with the plane in which the light beam  196  is projected by the long distance light beam projector  192  mounted in the rear end  194  of the towing vehicle module  302 . The light beam projector  304  thus functions similarly to the light beam projector  226  in the towed vehicle module  160 . 
     As with the towing vehicle module  288 , the light beams  294  and  296  intersect with each other on a line  308  extending along the hitch pivot axis  165  when the towing vehicle module  302  is properly mounted on a towing vehicle  26 , and the plane of the light beam  306  also includes the same line of intersection  308 . 
     Utilization of the hitch alignment system incorporating the just-described towing vehicle module  302  is basically similar to use of the system with the towing vehicle module  288  as described above, except that when the long distance light beam  196  is obscured, as the rear end  194  of the towing vehicle module  302  passes beneath the body  244  of the towed vehicle module  162 , the central light beam  306  still remains visible as a vertical line on the target face  246 , so that when the towing vehicle is correctly located in the mating location with respect to the towed vehicle or trailer  28  as shown in  FIG. 36  the projected light beams  294  and  296  and the vertical line of the projected beam  306  from the center light beam projector  304  all intersect at the center  258 . That is, the line of intersection  308  projects directly upward above the towing vehicle module  302  to the center  258  of the target face  246 . 
     As shown in  FIG. 37 , in many vehicles which might be utilized as towing vehicles  26 , rearwardly directed backup cameras  320  are provided as original equipment, to supply a video image to a video monitor incorporated in the dashboard of the vehicle. Since the lens of such a camera typically has a short focal length and wide-angle capability, the camera  320 , typically located higher than the trailer hitch drawbar  16  of such a vehicle, can be incorporated in the hitch alignment guidance system disclosed herein by placing a towed vehicle module  322  above the trailer hitch coupler  20  on the tongue  22  of a towed vehicle  28 , in an inverted orientation by comparison with the towed vehicle module  162  previously described. A towing vehicle module  324  may be attached to the rear of the towing vehicle  26 , supported on an appropriate bracket  326 , the details of which need not be described, except to say that the bracket must be designed or adjustable to support the towing vehicle module  324  in a position in which a main hitch alignment beam projector  328  is located directly above and aimed directly at the top of the trailer hitch ball  18  mounted on the drawbar  16 . Also, the mounting bracket  326  must be located in such a position that it does not screen the camera  320  from the hitch ball  18  when the towing vehicle  26  is approaching closely to the trailer  28 . As shown in  FIG. 37  a projected beam  330 , shown in solid line, may be a pinpoint beam or, preferably, a line scanning laser beam projecting a line oriented transversely with respect to the towing vehicle. The light beam  330  projected from the projector  328  may also be in the form of a cruciform scan centered on the hitch ball  18  and having forward and rearward portions indicated in broken line at  332  and aligned in a longitudinal plane with respect to the towing vehicle  26 . 
     A long distance light beam projector  336  located in the towing vehicle module  324  is provided to project a long distance beam  338  directly rearwardly from the towing vehicle  26 . The beam projector  336  may be a line producing scanning laser module scanning the laser beam  338  in a vertically and rearwardly aligned plane and through an angle great enough to project the line onto the front surfaces of a trailer or other vehicle  28  to be towed and also scanning downward directly onto the top of the hitch ball  18 . The beam  338  will thus fall onto the target face  346  of the towed vehicle module  322  so as to provide directional guidance to the operator of the towing vehicle  26  in the image transmitted by the camera  320  to the built-in video monitor in view of the operator of the towing vehicle  26 . 
     Referring now to  FIG. 38 , a mounting device  350  to be received in the coupler  22  of a towed vehicle instead of the ball  166  may incorporate a spring-loaded spacer to provide a snug, but adjustable retention without the weight of a metal ball and without the need for balls  166  of different sizes to fit different trailer hitch couplers  22 . A lower hemispherical portion  352  which may be somewhat less than a hemisphere has its truncated spherical surfaces  354  facing toward the body  244  of a towed vehicle module  162 , taking the place of the lower portion of a trailer hitch ball  166  when the mounting device  350  is captured in a trailer hitch coupler  22 . A body  356  of magnetic material, which may have the shape of a thick disk, is attached to the hemispherical portion  352 , so as to be attracted to the magnet  272  in the body  244 . A helical compression spring  362  is arranged to urge a cylindrical outer body  364  of the spacer away from the truncated spherical lower body  352 . A cylindrical spring socket  366  surrounds the lower end of the spring  362 , adjacent the hemispherical portion  352 . The cylindrical outer body  364  fits around the spring socket  366  and is movable toward or away from the lower body  352  as indicated by the arrow  368 . Interlocking snap rings  369  and  370  may be disposed in grooves in the spring socket  366  and outer body  364  to connect the outer body  364  to the spring socket  366  and retain the spring  362  under compression. To keep the mounting device  350  centered atop the body  244  a projection such as the hemispherical head  372  of a bolt  374 , used to attach the magnetic body  356  and the lower body  352  to the spring socket  366 , may stand proud of the magnetic metal body  356 , and a corresponding centrally located socket  376  may be provided on the top of the body  244 , surrounded by the annular magnet  272 , to form a swivel so that the body  244  will be located correctly with respect to the coupler  20  and will be able to be turned to a required directional alignment about the central axis of the trailer hitch coupler  20 . 
     The spring  362  can urge the convex upper end of the outer body  364  as a spacer against the upper interior of the coupler  20  and urge the spherical surface  354  against the lower interior clamping surfaces of the coupler  20  to hold the trailer-mounted module  162  adjustably but firmly in place. 
     The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.