Abstract:
A tow hitch for a vehicle with adjustments which simplify the coupling process. During coupling a draw bar, slideably positioned in a housing pocket, is afforded continuous adjustment latitude in both a left to right and front to back arc. Even if the vehicles are coupled at an angle, guide pins, confined by openings in the housing, move with the bar and respond to vehicle movement for an aligned locking and tow. An automatic locking pin secures the tow hitch, and a detector device detects the proper coupling.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to vehicle towing apparatus and methods for same. More specifically, the field of this invention relates to a steel hitch at the tow vehicle that will extend, swivel and automatically lock the towed and towing vehicles together in a simple and efficient manner. Additionally the field of this invention relates to a simple interchangeable draw bar that can be interchanged from ball to pintle or similar type coupling mechanisms for towing purposes. 
   Explanation of Terms 
   Set out below are brief descriptions of certain relevant terms which further the understanding of the invention. These terms provide a basis for a detailed teaching of the improvements of this invention in the relevant arts. Such terms are not intended to replace the claims but rather serve as helpful guides in understanding our novel improvements in these arts. 
   Centering Draw Bar 
   Towing is accomplished by a steel draw, pull or tow bar that has at its exposed end an opening for receiving a coupling device such as a ball/socket or a pintle hook. (See below.) The invention draw bar has four aligned openings with the tow-securing apparatus (whether drop socket or pintle) at the exposed rearmost position. The other three aligned openings in the draw bar receive, in order, a locking pin and a pair of movement control guide pins. The draw bar is moveably pinned to swing in an arc left to right, slide forward and back while being automatically lockable and manually releasable as desired. 
   Coupling Between Tow and Towed Vehicles 
   A ball and “lift and drop” coupling socket has the receiving socket on the to-be-towed (“towee”) vehicle and the ball on the towing vehicle. A pintle lock type has both ball and socket on the tow vehicle and is self closing upon contact with a receiving ring or opening on the to-be-towed vehicle. In the latter event, the receiving opening—say a steel ring on the towee vehicle is large enough in diameter and sturdy enough that contact with the pintle hook at the exposed end of the bar will allow the ring to drop over the pintle hook ball. Such pintle hooks are well known and many examples may be found that explain and depict them. For example, in the 2004 Issue of Northern Hydraulics at Catalog page 220 five different models are shown together with the flat steel adapter. In either event, however, the coupling end of the draw bar becomes selectively fastened to the receiving apparatus on the towee vehcile. 
   Adjustable Hitch Housing 
   A hitch housing for the tow provides limited and unique arc and extending/retracting freedom of movement for the draw bar during the coupling process. Movement control pins, once inserted via the top cover and retaining the draw bar within a pocket in the housing, are guided within confines established by a pair of aligned housing openings in the bottom cover. Together the pins and openings allow the draw bar a limited and unique freedom of movement that permits easy centering and automatic coupling between the tow and a towed vehicle. 
   Draw Bar Housing Openings 
   Two pins within the housing are located with side to side and back to front movement in a pair of housing openings. Taking the rear end of the tow vehicle as a reference point, the rearmost opening is a smaller triangular-shaped “piece-of-pie” opening; whereas the larger front opening is essentially a smooth heart-shaped opening. These openings have their points aligned along the center, or tow line, of the hitch for advantageous locking and movement purposes. The arc of the rear opening defines the amount of swivel and acts as a side to side pin guide. The arc at the base of the rear opening is matched by a reversed direction arc that forms the dip of the heart shaped front opening. Movement control pins trace out a pattern of movement within these housing openings in order to accomplish the novel features of this invention. 
   Automatic Locking Pin 
   A third opening in the housing is located at the extreme front end of the mounting plate. This locking pin opening is aligned with the points on the pie and heart shaped freedom-of-movement openings. Housed in the locking pin opening is a raised spring loaded taper pin that has a cross piece for manually lifting upon a coupling release. And, the taper pin acts as a detent which, being spring loaded, drops into a receiving opening in the draw bar for automatic locking purposes. Made of cold rolled steel, it is strong to bear the tow load. 
   2. Description of Prior Art 
   Towing hitches are, of course, well known. Also well known is the great difficulty in aligning the tow ball and the receiving socket, or cap, between the towing vehicle and the towed vehicle. Whether it is a pickup truck and a boat trailer, or a semi-sized RV and the trailing auto to be towed along behind the RV, such alignment poses severe problems for many people. A successful coupling of the two vehicles is normally a series of driver back and forth and turning right, turning left, inching forward and jerking back. 
   To add to the problem, these are mostly blind movements while someone else, in an almost equally blind and potentially dangerous position, tries to signal the desired movements necessary for a successful coupling to take place. Further still, there are also height adjustments needed along with the arc and back and forth in plane movements. 
   Highly summarized, a successful coupling between the two vehicles may generally be summarized as a frustrating and stress raising situation. In the RV world especially, men or women drivers being what they are, husband and wife both dread this connecting process. 
   Then, one must also add to the frustration, the weight of the towed vehicle. Take, for example, a boat on a trailer. Generally speaking after a try or two by the driver of the towing vehicle, the tow ball is only slightly off line, but the weight of the to-be-towed vehicle prevents manual movement as needed for an easy and successful coupling of the two vehicles. 
   Commercial sized vehicles have such a bulk and mass of steel that they often must use additional leverage provided by hydraulic rams or the like during the process of coupling together such very large vehicles. They are today a size once thought not possible. Yet such vehicles must still be connected together by some form of a tow hitch. It is a serious problem that, prior to the advent of this invention, remained unsolved. 
   This invention presents novel operational principles that are equally applicable to today&#39;s gigantic-sized earth moving equipment as it is to pickup trucks and boat trailers. Farm implements, bulldozers, excavators are among the many vehicles which will greatly benefit by the novel features presented herein. 
   In general then, what has not yet been provided, in order to fill a long sought for need, is a flexible, easy apparatus and method for connecting a tow hitch between vehicles. The invention provides a novel solution to this long sought for need by featuring a limited but highly successful freedom of movement in a confined amount of swivel and back/forth adjustments with automatic locking and manual dis-engagement to boot. 
   SUMMARY OF THE INVENTION 
   In the invention, a tow system is disclosed that has limited but highly beneficial movement during the coupling process between the tower and the towee vehicles. Such movement is provided by a novel dual plate mounting system on the tow side for housing a draw bar that adjusts in swivel and front to back during the centering process until the proper coupling position is achieved. Even when coupled at an angle (easily possible with this invention) our guide pins align the tow bar for coupling as vehicle movement takes place. Relative vehicle also locks the two vehicles movement together as well. 
   Attached to the housing and positioned above the draw bar is an automatic locking pin which is activated simply by vehicle movement during the initial start of the towing process. A signaling device detects the proper coupling and issues a signal to the driver of the tower vehicle as to the status of the coupling. 
   Achieved by this invention are some of the following features and benefits:
         Sturdy and position adjustable during coupling.   Readily interchangeable with diverse hitch types.   Easy to center during coupling movements.   Provides an automatic locking pin.   Self locking pin responsive to vehicle movement.   Safety lock for once coupled and locked hitch.   Guide pins which facilitate hitching and locking movements.   Durable pin strength during primary towing.   Guide pins that are readily receptive of a ram assist for large heavy duty situations.   Wide range of adjustment zone during coupling.   Manual disengage of locked position.   Vehicle movement both self aligns and locks the hitch.       

   
     DRAWINGS 
       FIG. 1  is a side view with the draw bar extended in accordance with the invention; 
       FIG. 2  shows a top view of a mounting housing plate with a pocket in dashed lines; 
       FIG. 3  depicts a view of a housing pocket on the parallel bottom mounting plate having draw bar movement capability in accordance with the principles of this invention; 
       FIG. 4  is a top view of a draw bar of the invention; 
       FIG. 5  is a side view of the side spacer plates that defines and forms the housing adjustment pocket as shown in  FIG. 3 ; 
       FIG. 6  is a top perspective of a pair of guide pins with collars; 
       FIG. 7  is an exploded view of the automatic locking pin in accordance with the invention; 
       FIG. 8  shows the components of  FIG. 7  in assembled condition; 
       FIG. 9  is a side view in exploded form showing the assembly of the tow hitch of the invention; 
       FIG. 10  includes three side by side bottom views depicting the draw bar movements for ease of coupling during a hitch; and 
       FIG. 11  shows a shaded area depicting the range of adjustment provided by the invention during a hitching process. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  depicts a side view of our hitch  50  wherein a housing  20  has a top plate  1 , bottom plate  2  and a pair of side filler plates  5  forming an interior pocket (shown dashed in  FIG. 2 , solid in  FIG. 3  and designated by space  60  in  FIG. 5 ) for draw bar  4  in housing  20  of  FIG. 1 . Hitch  50  is fastened to the rear frame of a tow vehicle in any conventional manner such as a custom receiver. 
   At the remote end of bar  4 ,  FIG. 1 , is a ball  7  (shown dashed since it is only one of several well known coupling devices such as the aforesaid pintle hook). One would have several draw bar types which may easily be interchanged within the principle of this invention. And, other coupling and securing types between the two vehicles may, of course, be used. 
   Centrally located in housing  20  of  FIG. 1 , draw bar  4  moves around in the pocket  60  ( FIGS. 2 and 3 ) in a manner to be described in detail hereinafter. Also depicted In  FIGS. 1 and 10  is a pair of guide pins  6 A and  6 B.  FIG. 9  is an exploded view that amply demonstrates that these pins  6  have collars  66  (see  FIG. 6 ) that are seated in recessed holes in the top of draw bar  4 . The thickness of the side plates  5  ( FIG. 5 ) and the draw bar  4  are chosen such that draw bar  4  can smoothly slide within the pocket  60  formed for it by housing  20 . 
   At the forward end of the housing, we have placed an automatic locking device  11 . This locking device  11  is shown in more detail in  FIGS. 7 and 8  and will be described further in conjunction with those figures. Briefly, however, the locking device  11  includes a tapered pin  10  ( FIG. 9 ) that is spring loaded and rides along on the upper surface of moveable draw bar  4 . The smaller tapered end of the locking pin, is urged by the spring  9  into the locking hole  22  of draw bar  4  when both are properly positioned for locking as will be described in more detail later on. 
     FIG. 2  depicts the top plate  1  of housing  20 . The two pairs of openings  21  represent the means for fastening the housing to the vehicle frame or custom receiver. These may be screws, bolts, welds or the like for the steel hitch  50 . Also note that top plate  1  includes, running from the arched front to back, three centrally located holes  22 ,  23  and  24  through top cover plate  1 . These holes are in alignment with the direction of tow  100  ( FIG. 10C ). 
   First opening  22  may be threaded or otherwise fashioned to retain the housing of automatic locking device  11 ,  FIG. 1 , while allowing the spring loaded end of the locking pin  10  to ride on the upper surface of the draw bar  4 . The next two openings,  23  and  24 , allow the guide pins  6 A and  6 B of  FIG. 6  to be inserted into the draw bar  4  through the top cover  1 . Once inserted, guide pins  6 A and  6 B remain in place and extend through the adjustment openings  25  and  30  of bottom plate  2 ,  FIG. 3 . 
   Turning now to  FIG. 3 , please note that the two adjustment openings  25  and  30  are in line with opening  22 . The first opening  25  is essentially triangular with a shape like a piece of pie in that it has a slight rounded arc at its base. Second opening  30  is essentially a smooth heart shape with the top of the heart having an arc that is reversed in contour from the arc of opening  25 . 
   These openings  25  and  30  receive the pins  6  which protrude slightly from the bottom of plate  2  as shown in the side view of  FIG. 1 .  FIG. 6  shows the pins  6  alone. When these pins  6  are dropped through openings  23  and  24  of top plate  1 , their collars  66  settle into recesses of appropriate depth so that the top surface of bar  4  is flush. 
     FIG. 9  depicts, in exploded view the top collars  66  on pins  6  and the manner in which they drop into the mating-sized recesses in the top of draw bar  4 .  FIG. 9  also makes clear that the openings  23  and  24  in top plate  1  are slightly oversized so that the collars  66  of pins  6  may be inserted into draw bar  4 . 
   If the user desires to change a coupling type, the user simply moves bar  4  until all three pins are aligned with the openings in both housing covers, and removes the pins from their position of support by the tow bar  4 . After withdrawing the first bar, the user may next insert a new draw bar. This second draw bar may have, say, a pintle hook in place on the exposed end of draw bar  4 . Reinserting the guide pins  6  with the new bar in place completes the coupling type change. 
   Note in  FIG. 1  that the rear pin  6 A is longer than the front pin  6 B and that its lower end protrudes an inch or so from the bottom surface of plate  2 . That protrusion allows an eye-type fastener from a ram  60  (shown symbolically by a double headed arrow) to be connected to rear pin  6  when the invention is applied to large commercial vehicles. Ram  60  is anchored to the frame and, being bi-directional, drives the draw bar  4  in movements, as needed, for a proper coupling. This described use and control of hydraulic or electric rams, especially in connection with desired movement in heavy and bulky situations, is well known. Thus, it is believed that no further description is needed. 
     FIG. 10  includes  FIGS. 10A ,  10 B and  10 C which are bottom views that show the freedom of movement of the draw bar  4  in the plane of the pocket  60  in housing  20 .  FIG. 10  also shows the detector  3  for determining the status of the coupling. Detector  3 , for example, would be viewed from the inside the tow vehicle to determine when a complete coupling has been achieved. A light inside the vehicle will shine green for “go” and red for “not yet properly coupled”. Such technology is well known and thus no further description is believed necessary. 
     FIG. 7  shows an exploded view of our automatic locking feature provided by pin  11 . In  FIG. 7 , a hollow cylindrical housing  41  is presented for receiving in turn, a tapered locking pin  10 , a spring  9 , and a keeper screw  8 . Housing  41  has a pair of opposed in line longitudinal slots  40  through the cylindrical side wall. Likewise taper pin  10  has a pair of opposed in line openings  42  there through. 
   As shown best in the assembled view of  FIG. 8 , rod  12  is secured in the slot pair and also through the openings  42  in tapered locking pin  10 . Rod  12  allows the user to lift up pin  10  and thus manually disengage the automatic locking feature. 
   Keeper  8  may be threaded into mating threads  43  in the open end  44  at the top of cylindrical housing  41 . Once assembled, with keeper  8  screwed in place, the taper end  45  of locking pin  10  will ride along on the upper surface  55  of draw bar  4  as bar  4  is moved around during the coupling process. 
   Draw bar  4 , as shown best in  FIG. 9 , also has a slightly oversized top opening  22  relative to the bottom  45  of locking pin  10  That opening is essentially matched to the taper of locking-pin  20 . Pin  10  will readily be urged by spring  9  into and fill opening  22  when the two are properly aligned. 
   Once locked, however, the movement of the coupled vehicle will cause bumps and wave-like actions by, stops, turns, towing and the like. Such movement might tend to unseat the taper pin  10  from its locked position. Accordingly, we have added a pendulum safety catch  13 ,  FIG. 7 , which is free to swivel about screw  16  in the housing  20 . Note how safety catch  13 ,  FIG. 7 , is more heavily weighted at the bottom so that gravity will aid it and cause catch  13  to drop into a safety catch position. 
     FIG. 10  includes  FIG. 10C  which shows that all three pins, the two guide pins  6  and the locking pin  12 , are in line for a tow along tow line  100 . When seated correctly, pin  12  locks automatically and distributes the shocks and give and take of a tow load. Comparison of  FIG. 10A  with  FIG. 10B  shows the extreme right and left swings for the extended draw bar  4   
   In order to activate the automatic locking feature, one simply couples the two vehicles—a lot easier and less frustrating task with this invention and its coupling adjustment range of  FIG. 11 , and moves the tow vehicle. Relative movement between the two vehicles causes the guide pins to move within the two openings  25  and  30  As the guide pins trace their location to the point positions, the draw bar opening  22 ,  FIG. 9 , moves under the tapered pin  10  and it drops into place. An indication by detector  3  would signal that a valid coupling has been achieved. 
   Note that it is the fan shape of the housing together with the guide pin control openings that allows a continuous and smooth movement of draw bar  4  into the locked position. Likewise,  FIG. 11  shows in a dotted grid  110  between lines  111  and  112  an indication of the range of adjustment for the given proportion of draw bar  4  and housing  20 . Modifications to those proportions, of course, will still be within the principles of our invention but will vary that adjustment area. 
   While our invention has been described with reference to particular examples of some preferred embodiments, it is our intention to cover all modifications and equivalents within the scope of the following claims. It is therefore requested that the following claims, which define our invention, be given a liberal interpretation commensurate with our contribution to the relevant technology.