Abstract:
A hitch adapter for coupling a first vehicle having a king pin mounted thereon to a standard ball hitch. The adapter comprises a vertically adjustable body and a remotely operated latching mechanism. The adapter may have a cone-shaped top with a serrated edge for securely attaching the adapter to a king pin box. The adapter further comprises a bell-shaped opening for receiving the ball hitch, the bell-shaped opening being larger than the ball hitch. The invention further comprises a method of coupling a first vehicle with a king pin and king pin box mounted thereon to a second vehicle with a ball hitch. A hitch adapter kit is also disclosed.

Description:
This application claims the benefit of Ser. No. 60/252,178, filed Nov. 21, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The current invention relates to an apparatus for connecting a motor vehicle to a trailer. Specifically, this invention relates to an apparatus which allows the user to couple a standard fifth-wheel trailer to a standard ball hitch on a motor vehicle. 
     2. State of the Art 
     Trailers, including cargo trailers, boat trailers, recreational vehicles, animal trailers, camping trailers and mobile homes, are designed to be towed behind a motor vehicle. During transport, the front end of the trailer is supported by and connected to the vehicle by an apparatus. A truck having a bed, with a connecting apparatus in the bed of the truck, is commonly used to tow trailers. A fifth-wheel trailer connects to a towing vehicle by a fifth-wheel hitch that is mounted on a frame within the vehicle bed such that the actual connecting apparatus is located above the plane of the truck bed. A gooseneck trailer connects directly to the towing vehicle via a ball hitch in the bed of the truck. 
     While trailer hitches are well known, numerous design drawbacks exist in the prior art. The fifth-wheel trailer connects to the hitch via the trailer&#39;s king pin box, which is located on the front end of the trailer. Fifth-wheel trailers commonly extend over at least a portion of the bed of the truck and attach to a hitch near the middle of the truck bed. Standard hitches are very costly, are difficult to install, and often require drilling of holes or other modifications to the truck bed and frame. The hitches are very heavy and very difficult to remove. The complex installation results in the hitch being semi-permanently attached to the towing vehicle, making removal of a standard hitch an arduous task. Therefore, a person who owns both a gooseneck trailer and a fifth-wheel trailer must necessarily own two different trailer hitches and a different trailer hitch must be installed, and/or removed, each time a different trailer is needed. Thus, it would be preferable to have a trailer hitch that was easy to install and remove. 
     Similarly, the prior art design is unsatisfactory because the hitch generally takes up considerable space in the bed of a truck, causing the bed area to be unusable. Because the standard hitch is typically semi-permanently installed, the valuable cargo space in the truck bed is unavailable even when a trailer is not coupled to the truck. Another limitation of the prior art is that it is difficult to mate the trailer to the coupling apparatus, further prolonging the installation process. Additionally, with the prior art design, a user must climb into the bed of the truck to lock or unlock the coupling apparatus. Finally, standard trailer hitches do not allow vertical adjustment to provide greater or lesser clearance between the side-boards of the bed of the truck and the trailer overshot. 
     Thus, it would be advantageous to provide a hitch adapter which allows the user to couple a standard fifth-wheel trailer to a standard ball hitch. Further, it would be advantageous to provide a hitch that is easy to install and remove and that permits vertical adjustment of the trailer. 
     BRIEF SUMMARY OF THE INVENTION 
     One embodiment of the present invention comprises a hitch adapter for coupling a first vehicle, having a king pin and king pin box, to a second vehicle with a ball hitch, wherein the adapter is easy to install. The hitch adapter includes a threaded collar assembly for attaching to the king pin, a vertically adjustable body including a top with an internal threaded section, wherein the internal threaded section is configured to mate with the threaded collar assembly, and a bottom having a bell-shaped opening for receiving the ball hitch, the bell-shaped opening being larger than the ball hitch, and a latching mechanism coupled to the vertically adjustable body, the latching mechanism being operated by a handle located remote from the hitch. 
     In a preferred embodiment, the latching mechanism comprises a latch pin configured to ride against a shoulder of a ball hitch, a positive wedge block for securing the latch pin against the shoulder of the ball hitch and for preventing the latch pin from disengaging from the ball hitch, two opposing side plates attached to the bottom of the vertically adjustable body on either side of the latch pin and the wedge block, a backup plate attached to the two opposing side plates, the backup plate for securing the wedge block against the latch pin, and a linear cable actuator housing a cable, the cable being attached at one end thereof to the wedge block and at the other end thereof to a handle, the handle for activating and releasing the latching mechanism wherein the handle is located remote from the bottom of the vertically adjustable body. 
     Another embodiment of the invention comprises a method of coupling a first vehicle with a king pin and king pin box mounted thereon to a second vehicle with a ball hitch. The method comprises attaching a threaded collar assembly to a king pin, screwing a vertically adjustable body onto the threaded collar assembly, wherein the vertically adjustable body comprises a first end having a slightly serrated top that grips the king pin box and an internal threaded section, and a second end having a bell-shaped opening for receiving the ball hitch, adjusting the vertically adjustable body to a height, aligning the bell-shaped opening within about two inches of the center of the ball hitch, coupling the vertically adjustable body to the ball hitch, and remotely activating a latching mechanism. 
     In a preferred embodiment, the vertically adjustable body allows a user to level the first vehicle for improved towing characteristics. 
     Another embodiment of the present invention comprises a hitch adapter for coupling any king pin to a ball hitch. The hitch adapter comprises a threaded collar assembly for attaching to the king pin, a vertically adjustable stem including a first end with an internal threaded section and a top, wherein the internal threaded section is configured to mate with the threaded collar assembly and the top is cone-shaped, slightly serrated and heat treated, and a second end having a bell-shaped opening for receiving the ball hitch, the bell-shaped opening being slightly larger than the ball hitch, and a latching mechanism attached to the vertically adjustable stem, the latching mechanism being operated by a handle located proximate the king pin. 
     Another embodiment of the present invention includes a ranch hitch adapter kit comprising a hitch adapter, including a threaded collar assembly for attaching to a king pin, a vertically adjustable body having a bell-shaped opening for receiving the ball hitch, the bell-shaped opening being larger than the ball hitch, and a latching mechanism coupled to the vertically adjustable body, the latching mechanism comprising a linear cable actuator housing a cable, the cable being attached at one end thereof to a handle, the handle for activating and releasing the latching mechanism, and a cable bracket, and a spanner wrench, wherein the spanner wrench is adapted to secure the vertically adjustable body against a king pin box. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is an exploded side view of a preferred embodiment of the component parts of the current invention in connection with a trailer having a king pin hitch and a towing vehicle having a standard ball hitch; 
     FIG. 2 is an exploded view of a preferred embodiment of the current invention; 
     FIG. 3 is a partial perspective view of a preferred embodiment of the present invention attached to a trailer having a king pin hitch; 
     FIG. 4 is a perspective view of one embodiment of the threaded collar assembly; and 
     FIG. 5 is a view of an embodiment of the split collar of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The current invention adapts any king pin style, fifth-wheel trailer king pin box  16  to attach to a standard ball hitch  14 , such as a 25/16 inch standard ball hitch. FIG. 1 illustrates an exploded view of one embodiment of the adapter  100  of the current invention comprising a vertically adjustable body and a threaded collar assembly  40 . In a preferred embodiment, the vertically adjustable body is a telescoping adapter body  20  with top half  22  and a bottom half  24 . The top half  22  comprises a first mating sleeve  5  which is configured to fit over a second mating sleeve  7 . The top of the first mating sleeve  5  comprises an internal threaded section  4  and a cone-shaped top  3 . 
     The bottom half  24  comprises the second mating sleeve  7  and a latching mechanism. In one embodiment, the latching mechanism comprises wedge block  10 , hardened latch pin  11 , backup plate  13 , linear cable actuator  12  housing cable  34 , cable bracket  18 , and handle  30  for activating and releasing the latching mechanism (shown in FIG.  2 ). The bottom of the second mating sleeve  7  houses a ball coupler assembly  60 . 
     The first mating sleeve  5  and second mating sleeve  7  are held together by one or more set screws  6  to form the adapter body  20 . By telescoping the mating sleeves  5 ,  7 , the current invention allows several inches of vertical adjustment of length of the adapter body  20 . Preferably, vertical adjustment of at least three inches is available. By loosening the set screws  6 , adjusting the mating sleeves  5 ,  7 , and then resetting the set screws  6 , the user can manipulate the adapter  100  to provide greater or lesser clearance between the side-boards of the bed of the truck and the trailer overshot. The vertical adjustment feature also permits the user to level the trailer with respect to the ground, providing for better towing. 
     The ball coupler assembly  60  comprises a top portion  8  and a bell-shaped opening  9  for mating with a standard ball hitch  14  of a towing vehicle. At the junction of top portion  8  and bell-shaped opening  9  is a milled slot that is configured to receive the hardened latch pin  11 . With prior art hitches, it is difficult to couple the trailer hitch to a standard ball hitch  14  because of the necessity to very accurately align the standard ball hitch  14  and the coupling apparatus. The bell-shaped opening  9  of the adapter  100  of the current invention allows the user to be off center, typically two or more inches off center, and still mate the adapter  100  and the standard ball hitch  14  without needing to jockey the truck around to achieve proper alignment for hookup. 
     In one embodiment of the latching mechanism of the current invention, a hardened latch pin  11  rides against the shoulder  19  of the standard hitch ball  14  to prevent the adapter body  20  from coming off the standard ball hitch  14 . The hardened latch pin  11  is held in the locked position by a wedge block  10  which, when in the down position, prevents the hardened latch pin  11  from disengaging from its locked position under the shoulder  19  of the standard ball hitch  14 . The hardened latch pin  11  is held captive in a milled slot  11 ′ in the side of the ball coupler assembly  60  (FIG.  1 ). The milled slot has a contoured shape matching the radius of the hardened latch pin  11 . 
     FIG. 2 illustrates one of two opposing side plates  32  which are welded to the ball coupler assembly  60  on either end of the hardened latch pin  11  (not visible in FIG. 2) and on either side of the wedge block  10  (not visible in FIG.  2 ). The side plates  32  laterally secure the wedge block  10  and have bolt holes, or apertures, to accept the bolts  38  holding the backup plate  13  in place. 
     Referring to FIG. 1, the wedge block  10  is held in place against the hardened latch pin  11  by the backup plate  13 . The backup plate  13  is bolted to the welded assembly of the ball coupler assembly  60  and the linear cable actuator  12 . The wedge block  10  is locked in the down position by a twistlock mechanism that is activated by a handle  30  located at the opposite end of the linear cable actuator  12  (FIG.  2 ). The handle  30  is preferably located remote from the ball coupler assembly  60 . When the handle  30  on the end of the cable  34  is pulled, the wedge block  10  is raised and the hardened latch pin  11  is allowed to roll away from the standard ball hitch  14 , thus allowing the adapter body  20  to be raised off the standard ball hitch  14  for disengagement from the towing vehicle. 
     Installation of the adapter  100  is a simple process in which the adapter body  20  is connected to the trailer king pin  17  of the trailer king pin box  16 . An experienced installer can install the adapter  100  in less than ten minutes. For ease of installation, the top half  22  can be separated from the bottom half  24 . FIGS. 1 and 5 illustrate the components of the current invention including the threaded collar assembly  40  comprising a split collar  2  and a threaded collar  1 . The threaded collar  1  is slid onto the trailer king pin  17 . 
     In the preferred embodiment, an anti-seize grease is applied to the threads of the split collar  2  so that the adapter body  20  may be removed at a later date if desired. The split collar  2  is made of two halves (FIG. 5) so the split collar  2  can be fitted around the recessed annular groove of any trailer king pin  17 . One side of each of the split collar halves has a chamfer and the chamfer side of the split collar halves faces downward when the collar halves are placed around the trailer king pin  17  and over the threaded collar  1 . The two halves of the split collar  2  are matched around the trailer king pin  17 . The split collar  2  is secured with Allen head studs that are introduced through a first collar half into a second collar half (not shown). 
     After the split collar  2  is installed in the groove of the trailer king pin  17 , the threaded collar  1  is slid down over the split collar  2  and the set screw  15  is tightened against the trailer king pin  17  to prevent the threaded collar assembly  40  from rotating when the top half  22  is threaded and tightened on the threaded collar assembly  40  (FIG.  1 ). 
     FIG. 4 shows another preferred embodiment of the threaded collar assembly  40 ′ 0  wherein the threaded collar  1 ′ is bored to the same internal diameter as the minor outer diameter of the annular groove of the trailer king pin  17  and is machined to a locking taper on the outer diameter. The locking taper is similar to a morse taper, or cone within cone design, used with a drill bit or to the taper of a split collar used with machinery to lock a sprocket or pulley to a shaft (FIG.  4 ). The tapered collar  2 ′ comprises two equal 180 degree segments which allow the tapered collar  2 ′ to collapse to a gripping fit around the neck of the trailer king pin  17  the same way a collet is designed to grip the shank of a tool. 
     The threaded collar  1 ′ is bored to a matching taper to the tapered collar  2 ′ outer diameter so as to slide down over the tapered collar  2 ′, thus locking the threaded collar  1 ′ around the neck of the trailer king pin  17  with adequate gripping force to prevent the threaded collar assembly  40 ′ from turning while installing the adapter body  20 . 
     To install the threaded collar assembly  40 ′, slide the threaded collar  1 ′ up over the major diameter of the trailer king pin  17 , insert the two halves of the tapered collar  2 ′ around the throat section of the trailer king pin  17  and slide the threaded collar  1 ′ down over the tapered collar  2 ′. The threaded collar  1 ′ can either be driven down over the tapered collar  2 ′ or pulled down with a wheel puller to mechanically lock the threaded collar  1 ′ into place. The threaded collar  1 ′ should be set with sufficient force to allow the necessary installation torquing of the top half  22  of the adapter body  20  as discussed herein. 
     After the threaded collar assembly  40  is secured to the trailer king pin  17 , the top half  22  of the adapter body  20  is attached to the threaded collar assembly  40  by hand screwing the top half  22  onto the threaded collar assembly  40 . The cone-shaped top  3  fits over the trailer king pin  17  and the internal threaded section  4  of the top half  22  of the adapter body  20  mates up to and screws onto the threaded collar assembly  40 . In a preferred embodiment, the top edge or corner of the cone-shaped top  3  is slightly serrated and heat treated. The serrated corner of the cone-shaped top  3  bites into the softer steel of the trailer king pin box  16 , allowing the adapter body  20  to lock onto the trailer king pin  17 , much the same as a lock washer used with a bolt and nut assembly, and prevents rotation of the adapter body  20  under normal use. The serrated edge on the cone-shaped top  3  provides a stabilizing element between the trailer king pin box  16  and the adapter  100  and eliminates the need for gussets, which are normally necessary in prior art designs. 
     Typically, the top half  22  can be secured against the trailer king pin box  16  using a wrench to at least 1,200 ft/lbs to ensure that the adapter  100  transfers the load of the trailer directly to the standard ball hitch  14 , and does not cause damage to the trailer or the towing vehicle due to excessive play. In a preferred embodiment, a commonly available wrench, such as a Spanner Wrench™, is used. A Spanner Wrench™ is a specially designed wrench that fits into a hole  36  (FIG. 2) in the first mating sleeve  5  and wraps around the top half  22  of the adapter body  20 . A long pipe on the end of the wrench may be needed to achieve the 1,200 ft/lbs torque when tightening the top half  22  of the adapter body  20 . 
     After the top half  22  is attached to the trailer king pin  17 , the bottom half  24  of the adapter body  20  is reinserted into the top half  22 . The adapter body  20  is set to the proper height to allow the trailer to adequately clear the side-boards of the towing vehicle&#39;s bed and the set screws  6  are tightened to 150 ft/lb. 
     The cable bracket  18  is attached to the underside of the trailer&#39;s overshot (FIG.  3 ). In a preferred embodiment, the cable bracket  18  is attached with self-drilling, self-tapping screws within 24 inches of the centerline of the trailer. A cordless drill with a {fraction (5/16)} inch socket is recommended for the easiest installation. The screws should be installed in the frame of the trailer, or the screws will eventually pull out of the thin fiberglass or aluminum sheet metal skin of the trailer. Installation of the cable bracket  18  within 24 inches of the centerline of the trailer prevents the cable  32  and cable bracket  18  from being crushed by the pickup&#39;s sideboards, which can happen when the trailer and the pickup become twisted in reference to each other on uneven surfaces as often found in campgrounds. Normally with a prior art fifth-wheel hitch, twisting would put tremendous strain on the frames of the truck and trailer because the fifth-wheel hitch prevented the truck and trailer from twisting in reference to each other. 
     If desired, the existing safety cable for the trailer&#39;s emergency disconnect brake is replaced with an extra-long safety cable. To replace the cable, the cable is crimped together with crimp sleeves. One end is attached to the trailer&#39;s emergency brake switch, and the other end is attached to the quick release snap. A stake pocket is located in the far upper comer of a pickup bed where a ¼ inch eye bolt can be installed. The quick release snap is attached to the ¼ inch eye bolt for the emergency disconnect brake cable. 
     When coupling the trailer to a prior art hitch, it is generally required to crawl into or reach into the truck bed to latch or unlatch the adapter locking mechanism. The current invention eliminates this practice with the combination of a linear cable actuator  12  and remote handle  30  located on the trailer at a convenient location where the user can latch or unlatch the hitch without the awkward problems the others present (FIG.  2 ). 
     Once the adapter  100  has been secured to the trailer king pin box  16  and the cable bracket  18  has been attached to the trailer frame, the trailer can be coupled to a standard ball hitch  14 . The latching mechanism is locked by twisting and pushing the handle  30  in as far as it will go and then twisting the handle  30  to lock it in position. 
     To detach the adapter  100  from the standard ball hitch  14 , the handle  30  is twisted, pulled out fully, and twisted again. This action raises the wedge block  10 , thus releasing the hardened latch pin  11 , and allows the ball coupler assembly  60  to fit over a standard ball hitch  14 . The trailer is raised to clear the standard ball hitch  14 , any wiring harnesses and safety cables are released, and the truck is driven out from under the trailer. 
     Other features and advantages of the present invention will become apparent to those of skill in the art through a consideration of the ensuing description, the accompanying drawings, and the appended claims.