Abstract:
Disclosed herein is a coupling assembly for use with a gooseneck trailer. The coupling assembly comprises a height-adjustment device and a coupler mechanism. The coupling assembly further comprises a locking assembly and a pair of friction fit assemblies. The height-adjustment device within the coupling assembly uses a load-bearing pin to concurrently and/or simultaneously perform two functions, namely permitting adjustablility of the coupling assembly and bearing all, or substantially all, of a vertical load (i.e., withstanding a shear force) provided by an attached gooseneck trailer, any trailer accessories, and any trailer contents. Because the load-bearing pin bears all, or substantially all, of the vertical load by resisting the shear force, conventional reliance upon a friction force to bear the vertical load is substantially eliminated. A tongue on the gooseneck trailer connects the gooseneck trailer to the coupling assembly and the coupler mechanism on the coupling assembly secures a ball mount on a towing vehicle to the coupling assembly. As such, the gooseneck trailer and the towing vehicle can be coupled and uncoupled. The locking assembly on the coupling assembly alternatively locks and unlocks the coupler mechanism. The friction fit assemblies on the coupling assembly inhibit relative side-to-side movement between an inner and outer member within the coupling assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application claims the benefit of the filing date of U.S. application Ser. No. 10/097,885, filed on Mar. 14, 2002, pending, which claims the benefit of U.S. provisional application Serial No. 60/318,227, filed on Sep. 7, 2001, expired.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention generally relates to a coupling assembly for securing a trailer to a  10 ′ towing vehicle. In one aspect, the coupling assembly comprises a coupler mechanism and a height-adjustment device, the height-adjustment device utilizing apertured coupling members and a load-bearing pin, the load-bearing pin being selectively insertable within the apertures in the coupling members to permit height adjustment of the coupler and to accept a vertical load delivered to the coupling assembly by the trailer.  
           [0004]    2. Description of the Related Art  
           [0005]    A typical trailer, such as a gooseneck trailer, comprises a trailer mount assembly and an attached coupling assembly. The coupling assembly is configured to receive a ball mount secured to a bed of a towing vehicle. When the coupling assembly receives and secures the ball mount, the towing vehicle is “coupled” to the trailer. When coupled, the towing vehicle can transport the trailer. When no longer needed, the trailer can be “uncoupled” from the towing vehicle by releasing the coupling assembly. When released, the ball mount is unsecured and discharged from the within the coupling assembly. Thereafter, the towing vehicle can proceed unencumbered by the trailer. The process of coupling, and uncoupling, can be repeatedly performed.  
           [0006]    Many conventional coupling assemblies include inner and outer tubular members associated with a variety of bolts, pins, and/or other connectors [hereinafter bolt]. The tubes are disposed in a telescopic mating, engagement. Therefore, the combined height of the tubes can be increased or decreased by sliding the tubes relative to each other. The bolt secured to the outer tube typically extends through an aperture in the outer tube and contacts the sliding surface of the inner tube. The bolt can thereafter generate friction at the inner tube to maintain the tubes at a desired, combined height. The friction supplied by the bolt permits the coupling assembly to bear a vertical load exerted by a trailer and its contents. Thus, conventional, adjustable coupling assemblies permit a trailer to be leveled and then secured for suitable towing using the force of friction generated by a bolt or like device. Unfortunately, the use of friction in a coupling assembly may permit slippage between the tubes if the force of friction should waver or be overcome.  
           [0007]    In U.S. Pat. No. 6,234,509 (Lara), telescopic, outer and inner tubes are employed in a coupling assembly. As illustrated in FIG. 6, an adjusting nut is secured to the outer tube proximate an outer tube aperture. The adjusting nut receives a corresponding adjusting bolt that can advance or retreat within the adjusting nut and outer tube aperture when rotated. When the desired height of the combined inner and outer tubes is achieved, the adjusting bolt is rotated until a distal end of the adjusting bolt is biased against the inner tube. With the distal end of the adjusting bolt lodged against the inner tube, friction is created between the distal end of the adjusting bolt and the inner tube. The adjusting bolt maintains the desired height of the combined inner and outer tubes and bears a portion of the vertical load provided by a trailer attached to the coupling assembly. Friction, and friction alone, permits the adjusting bolt in the coupling assembly to perform these two functions.  
           [0008]    In another embodiment of U.S. Pat. No. 6,234,509 (Lara), the use of a plunger pin assembly in combination with an adjusting bolt and nut is disclosed. As illustrated in FIGS. 4 and 5, the plunger pin assembly comprises a plunger pin (i.e., a non-threaded bolt) and a compression spring biasing the plunger pin. The plunger pin assembly is welded to the outer tube proximate an outer tube aperture. The inner tube contains a single column of inner tube apertures. When the outer tube aperture slidably aligns with one of the inner tube apertures, the plunger pin is released and inserted through the outer aperture as well as one of the inner tube apertures. Thereafter, the adjusting bolt is rotated until a distal end of the adjusting bolt is biased against the inner tube. The plunger pin, in combination with the adjusting bolt, maintains the desired height of the combined inner and outer tubes and bears the vertical load provided by the trailer attached to the coupling assembly. Therefore, friction and a shear withstanding force, in combination, allow the coupling assembly to provide height adjustment as well as bear the vertical load of the trailer and its contents. As such, friction is still being relied upon to assist in maintaining coupling assembly height.  
           [0009]    While the above coupling assemblies very capably permit towing of a trailer, an improved coupling assembly would be desirable.  
         SUMMARY OF THE INVENTION  
         [0010]    In one aspect, the invention provides a coupling assembly for use with a trailer such as a gooseneck trailer. The coupling assembly comprises a height-adjustment device and a coupler mechanism.  
           [0011]    The height-adjustment device includes an inner member, an outer member, and a load-bearing pin. The inner member has opposing inner member aperture pairs while the outer member has an opposing outer member aperture pair. The outer member telescopically, slidably receives the inner member such that the inner member can be height adjusted with respect to the outer member. The load-bearing pin is selectively insertable through one of the opposing inner member aperture pairs and the opposing outer aperture pair. In one embodiment, the inner member and the outer member can be elongate members that contain pairs of apertures that are circumferentially aligned.  
           [0012]    The coupler mechanism is secured to the height-adjustment device and engageable to a mount secured to a towing vehicle. The load-bearing pin can bear substantially all of a vertical load exerted upon the coupling assembly. In one embodiment, the load-bearing pin can bear any vertical load exerted upon the coupling assembly.  
           [0013]    The coupling assembly can include a friction fit assembly that is employed to maintain co-axial alignment of the inner member and the outer member. The friction fit assembly and the load-bearing pin can be longitudinally disposed along the outer member at approximately the same height. The friction fit assembly can include a fixed nut, a lock nut, and an adjustment bolt.  
           [0014]    The coupling assembly can also contain a locking assembly to alternatively ensure securement and permit release of the mount within the coupler mechanism. The locking assembly can be assembled from a locking pin, a locking pin spring, a locking pin handle, and a locking pin cover.  
           [0015]    A tongue on the trailer can connect the trailer to the coupling assembly. Further, the coupler mechanism on the coupling assembly can secure the mount on the towing vehicle to the coupling assembly.  
           [0016]    In one embodiment, the load-bearing pin can be angled proximate one end and contain a load-bearing pin aperture proximate another end. A cotter pin can be securable within the load-bearing pin aperture to secure the load-bearing pin within the coupling assembly.  
           [0017]    The inner member can define an inner member height and the outer member can define an outer member height. Therefore, when the inner member height and the outer member height are summed, a device height is defined. The device height can be adjusted to level the trailer with respect to a towing vehicle, the gooseneck trailer, or a combination of the towing vehicle and the gooseneck trailer.  
           [0018]    In another aspect, the invention provides a system for adjusting coupling assembly height. The system comprises a coupling assembly, which contains a height-adjustment device and a coupler mechanism, and a gooseneck trailer, which contains a tongue connecting the gooseneck trailer to the coupling assembly. The system uses the height-adjustment device such that a load-bearing pin is securable within one of opposing inner member aperture pairs and a opposing outer member aperture pair to adjust the coupling assembly height. The load-bearing pin can also bear substantially all of a vertical load exerted upon the coupling assembly.  
           [0019]    The system can further include the towing vehicle and the coupler mechanism. The coupler mechanism can be releasably engaged to the mount secured to the towing vehicle. The coupler mechanism can also alternatively permit coupling and uncoupling of the gooseneck trailer to and from the towing vehicle.  
           [0020]    In yet another aspect, the invention provides a method of leveling a trailer. The method can comprise initially providing a coupler mechanism and a height adjustment device. The height adjustment device can include an inner member, which has opposing inner member aperture pairs and defines an inner member height, and an outer member, which has an opposing outer member aperture pair and defines an outer member height. The outer member telescopically, slidably receives the inner member. The height-adjustment device also includes a load-bearing pin that can be selectively insertable through one of the opposing inner member aperture pairs and the opposing outer member aperture pair.  
           [0021]    The inner member and the outer member can be adjusted relative to each other such that a desired height is achieved and a channel is formed proximate the desired height. Thereafter, the load-bearing pin can be inserted within the channel formed by the adjusted members such that the load-bearing pin bears substantially all of a vertical load provided by the trailer while maintaining the desired height of the trailer. This can ensure that the trailer is leveled. The method can further comprise securably receiving a mount within the coupler mechanism where the mount is secured to a towing vehicle.  
           [0022]    In one embodiment, the method can include providing a friction fit assembly for promoting co-axial alignment of the inner member and the outer member. Further, the method can also include providing a locking assembly for preventing undesirable disengagement of a mount securably received within the coupler mechanism. In one embodiment, the locking assembly includes a locking pin such that the locking pin can be manually manipulatable to alternatively couple and uncouple the mount and the coupler mechanism. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    Embodiments of the invention are disclosed with reference to the accompanying drawings and are for illustrative purposes only. The invention is not limited in its application to the details of construction or the arrangement of the components illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in other various ways. Like reference numerals are used to indicate like components.  
         [0024]    [0024]FIG. 1 illustrates a side, elevational view of a trailer employing an embodiment of a coupling assembly, according to one aspect of the invention, and secured to a towing vehicle.  
         [0025]    [0025]FIG. 2 illustrates a side, elevational view of the coupling assembly of FIG. 1.  
         [0026]    [0026]FIG. 3 illustrates a side, elevational view of the coupling assembly of FIG. 2 rotated ninety degrees about axis A.  
         [0027]    [0027]FIG. 4 illustrates a top, cross-sectional view, taken along lines  4 - 4  of FIG. 2 of a height-adjustment device and a friction fit assembly.  
         [0028]    [0028]FIG. 5 illustrates a side, cross-sectional view, taken along line  5 - 5  of FIG. 4, of the height-adjustment device.  
         [0029]    [0029]FIG. 6 illustrates a top, plan view of the load-bearing pin and cotter pin used in the height-adjustment device of FIG. 5.  
         [0030]    [0030]FIG. 7 illustrates a side, elevational view of a trailer employing the height-adjustment device of FIG. 5 (within the coupling assembly of FIG. 2) to control trailer pitch.  
         [0031]    [0031]FIG. 8 illustrates a side, elevational view of a coupler mechanism within a lower portion of the coupling assembly of FIG. 2.  
         [0032]    [0032]FIG. 9 illustrates a top, cross-sectional view, taken along line  9 - 9 , of the lower portion of the coupling assembly of FIG. 8 with a lock plate shown in the open position.  
         [0033]    [0033]FIG. 9A illustrates a top, cross-sectional view, taken along line  9 - 9 , of the lower portion of the coupling assembly of FIG. 8 with the lock plate shown in the closed position.  
         [0034]    [0034]FIG. 10 illustrates a perspective view of another embodiment of a height-adjustable coupling assembly.  
         [0035]    [0035]FIG. 11 illustrates a top, cross-sectional view, taken along lines  11 - 11  of FIG. 10 showing another embodiment of a height-adjustment device having a plurality of friction fit assemblies. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]    In FIG. 1, towing vehicle  2 , trailer  4 , and trailer mount assembly  6  are illustrated. Towing vehicle  2  comprises a rear axle  8  and a towing vehicle bed  10 , the bed having bed aperture  12  disposed therein. Trailer  4  can comprise any conventional trailer for transporting cargo and the like and defines trailer end area  14 . Trailer mount assembly  6  comprises first tongue end  16 , second tongue end  18 , and tongue  20  disposed between the first and second tongue ends. In the embodiment shown, tongue  20  comprises a gooseneck-shaped tongue and, therefore, trailer  4  is known as a gooseneck trailer. Tongue  20  can extend over towing vehicle bed  10  such that second tongue end  18  is vertically disposed above rear axle  8  of towing vehicle  2 . Directional arrow  22  indicates the direction of a vertical load (and resultant shear force) created by trailer  4 , any trailer accessories (e.g., tongue  20 ), and any trailer contents. Trailer  4  is secured to first tongue end  16  at trailer end area  14 , typically by welds  24  or other conventional means. Also, second tongue end  18  is secured, typically by welds  24  or other conventional means, to coupling assembly  26 .  
         [0037]    As illustrated in FIG. 2, coupling assembly  26  comprises height-adjustment device  28  and coupler mechanism  30 . Optionally, coupling assembly  26  further comprises locking assembly  32  and friction fit assembly  34 . In preferred embodiments, height-adjustment device  28  is disposed at an upper portion  36  of coupling assembly  26 . FIG. 3 depicts coupling assembly  26  of FIG. 2 rotated ninety degrees about axis A. FIGS. 2 and 3, in combination, illustrate the various devices, mechanisms, and assemblies relative to each other in preferred embodiments.  
         [0038]    In FIG. 4, a top, cross-sectional view of coupling assembly  26 , taken along line  4 - 4  of FIG. 2, details height-adjustment device  28  and friction fit assembly  34 . As shown, height-adjustment device  28  comprises load-bearing pin  38 , inner member  40 , and outer member  42 . Inner member  40  defines inner member periphery  44 , inner member first surface  46 , and inner member second surface  48 .  
         [0039]    In FIG. 5, a side, cross-sectional view, taken along line  5 - 5  of FIG. 4, illustrates the interaction between inner member  40  and outer member  42 . As shown, inner member  40  includes opposing inner member aperture pairs  50 . Each aperture  52  within opposing inner member aperture pairs  50  extends from inner member first surface  46  to inner member second surface  48 . Opposing inner member aperture pairs  50  are longitudinally spaced over all, or a portion, of inner member height  54  and circumferentially aligned about inner member periphery  44  (FIG. 4). While FIG. 5 illustrates five pairs  50  of apertures  52 , the number of pairs employed can be varied to convenience.  
         [0040]    Referring back to FIG. 4, outer member  42  extends around, and is in telescopic, sliding engagement with inner member  40 . Outer member  42  defines outer member periphery  56 , outer member first surface  58 , and outer member second surface  60 .  
         [0041]    As shown in FIG. 5, outer member  42  includes opposing outer member aperture pair  62 . Each aperture  64  within opposing outer member aperture pair  62  extends from outer member first surface  58  to outer member second surface  60 . Opposing outer member aperture pair  62  is circumferentially-aligned about outer member periphery  56  to correspond to the circumferential alignment of opposing inner member aperture pairs  50  about inner member periphery  44 . Outer member  42  defines outer member height  66 .  
         [0042]    The telescopic, sliding inner and outer members  40 ,  42  are co-axially aligned about axis A, as shown in FIGS. 4 and 5, such that the members exhibit a mating engagement. Peripheries  44 ,  56  (or corresponding cross-sections) of both inner member  40  and outer member  42  can comprise a multitude of shapes, for example, circular, square, rectangular, and the like. In one embodiment, inner member  40  and outer member  42  comprise hollow, elongate members (e.g., tubes). In a preferred embodiment, the elongate members are tubular.  
         [0043]    When added together, inner member and outer member heights  54 ,  66  define device height  68  (FIG. 5). As members  40 ,  42  are telescopically, slidably manipulated with respect to each other, device height  68  can increase or decrease. As device height  68  changes, one of opposing inner member aperture pairs  50  can align with opposing outer member aperture pair  62  to form channel  70  through height-adjustment device  28  and, therefore, coupling assembly  26 . Channel  70 , when formed, is capable of receiving load-bearing pin  38 .  
         [0044]    To operate height-adjustment device  28 , and therefore coupling assembly  26 , a desired device height is determined. Thereafter, members  40 ,  42  are slidably adjusted relative to each other until the desired device height is achieved. Since inner member  40  comprises a plurality of opposing inner member aperture pairs  50  spaced along inner member height  54 , channel  70  can be formed at (or very near) the desired device height. With channel  70  formed at or near the desired device height, load-bearing pin  38  is inserted into the channel. As a result, load-bearing pin  38  occupies one of opposing inner member aperture pairs  50  and occupies opposing outer member aperture pair  62 . Should a new desired height be determined, load-bearing pin  38  can be removed, members  40 ,  42  re-adjusted, and the load-bearing pin re-inserted.  
         [0045]    When occupying channel  70 , load-bearing pin  38  can maintain the desired height of the coupling assembly  26  and can concurrently and/or simultaneously bear the vertical load (i.e., withstand the shear force) generated by the attached trailer, any trailer accessories, and any trailer contents.  
         [0046]    In one embodiment, load-bearing pin  38  can maintain the desired height of the coupling assembly  26  and concurrently bear all, or substantially all, of the vertical load (i.e., withstand the shear force) of the attached trailer, trailer accessories, and trailer contents. As used herein, the term substantially all is defined as approximately ninety-five percent (95%) of the vertical load.  
         [0047]    Thus, load-bearing pin  38  permits adjustablility of height-adjustment device  28 , and therefore coupling assembly  26 , while bearing the vertical load (i.e., withstanding the shear force) supplied by the attached trailer, any trailer accessories, and any trailer contents. These two functions are simultaneously and/or concurrently performed without relying on friction.  
         [0048]    In a preferred embodiment, as shown in FIG. 6, load-bearing pin  38  comprises a solid, elongate member having load-bearing pin aperture  74  proximate a first load-bearing pin end  76 . Load-bearing pin aperture  74  extends laterally, and entirely through, opposing sides of load-bearing pin  38 . Load-bearing pin aperture  74  is designed and configured to receive a cotter pin  72 , a hair pin, or other like securing device. As illustrated in FIG. 6, load-bearing pin  38  can be tapered at first load-bearing pin end  76  and angled proximate second load-bearing pin end  78 . Load-bearing pin  38  can be constructed of steel, or other like material, and is designed to withstand at least about thirty-two thousand five hundred pounds (32,500 lbs.) of shear force applied transverse (i.e., perpendicular) to axis B. In preferred embodiments, load-bearing pin is capable of withstanding at least about thirty-nine thousand pounds (39,000 lbs.) of shear force applied transverse (i.e., perpendicular) to axis B. In more preferred embodiments, load-bearing pin is capable of withstanding at least about fifty thousand pounds (50,000 lbs.) of shear force applied transverse (i.e., perpendicular) to axis B.  
         [0049]    Referring to FIG. 7, adjustment of device height  68  (FIG. 5) permits angle  80 , representing trailer pitch or level, to be customized. This can be highly desirable if bed height  82  above road surface  84  is not constant. For example, bed height  82  can vary with different towing vehicles  2 , as trailer  4  endures variable loading conditions, and the like. In preferred embodiments, height-adjustment device  28 , and therefore coupling assembly  26 , is manipulated such that angle  80  comprises approximately ninety degrees. This permits trailer  4  to be approximately horizontal with respect to towing vehicle  2  and road surface  84 .  
         [0050]    In FIG. 8, a lower portion  86  of coupling assembly  26  details coupler mechanism  30 . Coupler mechanism  30  comprises stationary plate  88 , lock plate  90 , pivot pin  92 , retainer bracket  94 , lock pin  96 , and spacers  98 .  
         [0051]    Stationary plate  88  comprises concave cavity  100 , flange  102 , first stationary plate aperture  104 , and second stationary plate aperture  106 . Stationary plate  88  can also comprise retainer bracket  94  secured to top stationary plate surface  122  proximate lock plate assembly end  124 , typically by welds  24 . Retainer bracket  94  comprises retaining plate aperture  95 .  
         [0052]    Concave cavity  100  extends upwardly into inner member  40  and is configured to receive mount  108  (e.g., a ball mount). Mount  108  can be secured within bed aperture  12  disposed in towing vehicle bed  10  of towing vehicle  2  (FIG. 1). Flange  102  provides a locale for inner member  40  to be secured to stationary plate  88 , typically by welds  24 . Resultantly, height-adjustment device  28  is secured to coupler mechanism  30 , to form coupling assembly  26 , and inner member  40  generally extends vertically, upwardly from stationary plate  88 . Inner member  40  can be solid, or substantially solid, so long as mount  108  can still be received in concave cavity  100  of stationary plate  88 .  
         [0053]    Referring to FIGS. 8, 9, and  9 A, lock plate  90  comprises mount aperture  110 , first lock plate aperture  112 , a locked-open aperture  114 , and a locked-closed aperture  116 . Mount aperture  110  is configured to receive and selectively secure mount  108 . As shown in FIG. 8, pivot pin  92  occupies first stationary plate aperture  104 , one of spacer aperture  99 , and first lock plate aperture  112 .  
         [0054]    Again referring to FIG. 8, lock pin  96  occupies retaining plate aperture  95 , second stationary plate aperture  106 , and another one of spacer aperture  99 . Retaining plate aperture  95  functions to prevent lock pin  96  from losing alignment with second stationary plate aperture  106  disposed beneath locking assembly  32 . Lock pin  96  next alternatively occupies either locked-open aperture  114  or locked-closed apertures  116 , as highlighted in FIGS. 9 and 9A, to secure mount  108  within coupling assembly  26 . FIG. 9 represents a top, cross-sectional view, taken along line  9 - 9 , of the coupler mechanism  30  from FIG. 4. In FIG. 9, stationary plate  88  and lock plate  90  are aligned and therefore receive mount  108  within coupler mechanism  30 . As shown, lock pin  96  is disposed within locked-open aperture  114 . Thus, lock plate  90  is secured, with respect to stationary plate  88 , in an open position.  
         [0055]    With mount  108  received in coupler mechanism  30 , lock pin  96  is slid upwardly and removed from locked-open aperture  114 . Lock plate  90  can then be rotated about pivot pin  92 , with respect to stationary plate  88 , causing the lock plate and the stationary plate to become offset, as illustrated in FIG. 9A. When the two plates  88 ,  90  are offset, mount aperture  110  is effectively constricted. As shown in FIG. 9A, lock pin  96  is then released and inserted within locked-closed aperture  116 . Thus, lock plate  90  is secured, with respect to stationary plate  88 , in a locked position. In the locked position, mount  108  is retained within coupler mechanism  30  and, correspondingly, coupling assembly  26 . To once again release mount  108  from coupler mechanism  30 , the above-described method is repeated in reverse order.  
         [0056]    Conventional coupler mechanisms, coupling assemblies, and methods of using the same, are detailed in U.S. Pat. Nos. 5,382,109 and 6,234,509, the disclosures of which are incorporated herein by this reference.  
         [0057]    In FIGS. 3 and 8, a preferred embodiment of locking assembly  32  is shown. Locking assembly  32  comprises lock pin  96 , guide  124 , spring  126 , and cover  128 . In FIG. 8, locking assembly  32 , with partially cut-away cover  128 , is illustrated in detail. Guide  124  is attached to inner member  40 , typically by one or more welds (not shown), thus securing locking assembly  32  to coupling assembly  26 . As shown, locking pin  96  is slidably secured within guide  124  to permit vertical actuation of the locking pin. In preferred embodiments, locking pin  96  comprises a “D-shaped” handle  130 , as illustrated in FIG. 8, to assist manual biasing of locking assembly  32 . With lock plate  90  secured courtesy of locking assembly  32 , coupling assembly  26 , and therefore trailer  4 , are prevented from undesirably disengaging from mount  108 , and therefore towing vehicle  2 .  
         [0058]    In FIG. 4, a cross-section of friction fit assembly  34  is shown. Friction fit assembly  34  comprises adjustment bolt  132 , fixed nut  134 , and lock nut  136 , each of which is threaded in preferred embodiments. Fixed nut  134  can be secured, typically by one or more welds  24 , to outer member  42  proximate adjustment bolt aperture  138 . Fixed nut  134  receives adjustment bolt  132  and, as the adjustment bolt is rotated, adjustment bolt end  140  travels through adjustment bolt aperture  138  in outer member  42  and is moved closer to, or farther away from, inner member  40  depending on the direction of rotation of the adjustment bolt. In a preferred embodiment, adjustment bolt  132  is rotated clockwise to bias adjustment bolt end  140  against inner member first surface  48 . Once adjustment bolt end  140  is biased against inner member first surface  48 , lock nut  136  can be rotated such that the lock nut is secured against fixed nut  134 . Friction fit assembly  34  inhibits relative side-to-side movement between inner and outer members  40 ,  42 . In other words, friction fit assembly encourages both inner and outer members  40 ,  42  to remain co-axially aligned about axis A. In preferred embodiments, friction fit assembly  34  does not carry a significant vertical load (i.e., withstand a significant shear force) supplied by trailer  4 , trailer accessories, and trailer contents, even though the friction fit assembly may have the ability to do so.  
         [0059]    [0059]FIG. 10 illustrates a perspective view of another embodiment of a height-adjustable coupling assembly. A coupling assembly  200  is shown. Coupling assembly  200  includes a height-adjustment device  202  and a coupling mechanism  204 . The height adjustment device  202  comprises: an inner member  206  comprising opposing inner member aperture pairs  208  (the apertures on the reverse side not shown). The device  202  further includes an outer member  210  comprising an opposing outer member aperture pair  212  (shown with pin  214 ) inserted therethrough). The outer member telescopically, slidably receives the inner member  206  such that the inner member can be height adjusted with respect to the outer member. A load-bearing pin  214  is selectively insertable through one of the opposing inner member aperture pairs  208  and the opposing outer member aperture pairs  212  and is used to both position the outer member with respect to the inner member and to bear substantially all of a vertical load exerted upon the coupling assembly. A first friction fit assembly  216  is in threaded engagement with the outer member  210  to maintain coaxial alignment between the inner member  206  and the outer member. A second friction fit assembly  218  is disposed above the first friction fit assembly  216  in threaded engagement with the outer member  210 , the second friction fit assembly maintains coaxial alignment of the inner member and the outer member (particularly when the coupling assembly is use). Finally, the coupling assembly includes a coupler mechanism  204  secured to the height-adjustment device, the coupler mechanism engageable to a mount secured to a towing vehicle (see FIG. 1).  
         [0060]    [0060]FIG. 11 illustrates a top, cross-sectional view, taken along lines  11 - 11  of FIG. 10 showing another embodiment of a height-adjustment device having a plurality of friction fit assemblies. Referring to FIGS. 10 and 11, the first and second friction fit assemblies inhibit relative side-to-side movement between the inner and outer members. The first and second friction fit assemblies promote coaxial alignment of the inner and outer members. The first friction fit assembly  216  includes a bolt  220   a  that passes through a first friction fit adjustment aperture (see FIG. 4) in the outer member  210 , and the second friction fit assembly  218  includes a bolt  220   b  that passes through a second friction fit adjustment aperture in the outer member (FIG. 11). In one embodiment, the first and second friction fit adjustment apertures are substantially the same size. In one embodiment, the first and second friction fit adjustment apertures are vertically aligned along the outer member as shown. In one embodiment, the opposing outer member aperture pair defines a height adjustment plane  222  and the first and second friction fit adjustment apertures define a friction fit assembly plane  224 , such that the height adjustment and friction fit assembly planes are perpendicular to each other. In one embodiment, the first and second friction fit assemblies do not carry a significant portion of the vertical load exerted upon the coupling assembly. In one embodiment, the first and second friction fit assemblies are not used to position a relative height of the outer member with respect to the inner member.  
         [0061]    In one embodiment, the opposing outer member aperture pair  212  (with pin  214  therethrough) and one of the first and second friction fit assembly adjustment apertures  215  defines an arc angle Ψ or Ω of or about 90 degrees.  
         [0062]    Despite any methods being outlined in a step-by-step sequence, the completion of acts or steps in a particular chronological order is not mandatory. Further, modification, rearrangement, combination, reordering, or the like, of acts or steps is contemplated and considered within the scope of the description and claims.  
         [0063]    While the present invention has been described in terms of the preferred embodiment, it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.