Patent Publication Number: US-2002003342-A1

Title: Self-aligning hitch

Description:
[0001] This application is a continuation-in-part of U.S. patent application no. 09/612,569, filed Jul. 7, 2000. 
    
    
     
       TECHNICAL FIELD  
       [0002] This invention pertains to hitches, and more particularly to self-aligning hitches for coupling two imprecisely aligned vehicles, for example, a towing vehicle and a trailer vehicle.  
       BACKGROUND  
       [0003] Hitches are in wide use for towing many kinds of trailer vehicles by towing vehicles. Most traditional hitches comprise the combination of a first coupling means (for example, a ball) attached to one of the vehicles and a second coupling means (for example, a hollow, hemispherical coupler) attached to the other. Since such conventional coupling means are fixedly attached to the vehicles, it is necessary for the vehicles to be brought into precise alignment in order to achieve coupling. This can be a difficult and time-consuming task. In circumstances where precise alignment is not achieved, it may be possible to manually move the trailer vehicle to a position for coupling to the towing vehicle. While this may be acceptable for lightweight trailer vehicles, it is a near-impossible task for heavier trailer vehicles such as loaded airport freight carts. Persons attempting to manually position a heavy trailer vehicle may suffer injuries.  
       [0004] Further, it is desirable to prevent the need for a second person to assist in coupling the towing and trailer vehicles. In general, having a second person, located behind the towing vehicle, to direct the operator of the towing vehicle presents dangerous circumstances. Further, it is inefficient to require two people to achieve a result which could be accomplished by a single person.  
       [0005] In general, the prior art has attempted to address these problems with the provision of a hitch assembly comprising a tongue or rod which is slidably insertable into a housing mounted on one of the vehicles and which is capable of some longitudinal and lateral movement so that a rearward end of the tongue, fitted with a coupling means, can be manually positioned to engage the corresponding coupling means on the other vehicle. The hitch assemblies of some prior art references provide an automatic locking mechanism which locks the tongue into a “locked” position.  
       [0006] However, the prior art hitch assemblies may suffer from one or more disadvantages. For example, several prior art hitch assemblies have been designed in such a way that it is only possible for the tongue to move to the “locked” position after the tongue becomes aligned with the vehicles. As a result, after the vehicles are coupled and the towing vehicle is moved forward from a slightly displaced lateral position (relative to the trailer vehicle), the tongue may be susceptible to banging from side to side within the housing until the tongue and the two vehicles achieve precise alignment. This is disadvantageous since it: (1) may damage the sides of the housing, ultimately requiring repair or replacement; and (2) may place undue pressure on the pivot pin retaining the proximal end of the tongue within the housing. After a period of time, the pin may become damaged to the point where repair or replacement is necessary.  
       [0007] Along the same lines, several prior art hitch assemblies are designed in such a way that lateral movement of the tongue is not immediately possible after the locking mechanism is disengaged. Rather, the operator is required to withdraw the tongue entirely, or nearly so, from within the housing until lateral movement of the tongue is possible. This limits the use of the hitch assembly. In some circumstances, the operator may have backed the towing vehicle into close proximity to the trailer vehicle so that the tongue cannot be fully withdrawn since it will engage the front portion of the trailer vehicle. Since lateral movement is then not possible (since the tongue is not capable of being fully extended from the housing), the operator would be forced to get back into the towing vehicle and move it ahead to create sufficient space between the vehicles to enable full extension of the tongue, and thus, lateral movement of the tongue. This adds unnecessary time and effort into the process, and could be eliminated if one could laterally position the tongue immediately upon disengagement of the locking mechanism.  
       [0008] Prior art hitch assemblies which may suffer from one or both of the above-noted disadvantages are described in: U.S. Pat. No. 3,912,119, issued to Hill et al., U.S. Pat. No. 2,871,029, issued to Demarest, U.S. Pat. No. 3,860,267, issued to Lyons and U.S. Pat. No. 4,991,865, issued to Francisco.  
       [0009] The hitch assemblies described in Demarest, Hill et al., and Francisco may be susceptible to damage to the housing while the tongue is moving into the housing and towards its locked position from either side-to-side banging of the tongue therein, or from the longitudinal engagement of a proximal end of the tongue on a closed interior of the housing.  
       [0010] Other prior art hitch assemblies include overly complex mechanisms which may render the hitch assembly too expensive for commercial application or too cumbersome for retrofitting existing towing vehicles. For example, U.S. Pat. No. 4,558,883, issued to Bouma, discloses such a complicated hitch mechanism.  
       [0011] Some prior art hitch assemblies, such as the one disclosed in U.S. Pat. No. 5,277,447, issued to Blaser, disclose housing and tongue designs which allow limited lateral movement of the tongue. This may be disadvantageous if the towing vehicle is sufficiently misaligned relative to the trailer vehicle to be outside the lateral movement range of the tongue. Repeated positioning of the towing vehicle relative to the trailer vehicle would be required to overcome such a limitation.  
       SUMMARY OF INVENTION  
       [0012] It is an object of the present invention to provide a hitch for coupling two vehicles, particularly in situations where the vehicles are misaligned.  
       [0013] In accordance with an aspect of this invention, a hitch for coupling a first vehicle to a second vehicle is disclosed. The hitch comprises: (a) a tongue housing for attaching to the first vehicle, the tongue housing having a forward end and a rear end, the tongue housing comprising a top wall, a bottom wall spaced apart from the top wall by two spaced apart side walls disposed therebetween, the top, bottom and side walls defining a throat, the throat having an open first end and an open second end; (b) a first guide member attached to the housing, comprising: (i) a first cam member; (ii) a first pocket and a second pocket, the first and second pockets being located on either side of the first cam member; (c) a tongue having a first end and a second end, the tongue being extendable and retractable within the throat, the tongue having a width narrower than the distance between the two spaced apart side walls of the tongue housing; (d) retaining means for preventing the tongue from being removed from the throat; (e) a second guide member, coplanar with the first guide member and attached to the second end of the tongue, the second guide member comprising: (i) a second cam member and a third cam member; (ii) a third pocket located between the second and third cam members; (f) a coupler attached to the second end of the tongue; wherein the first and second guide members become matingly engaged upon retraction of the tongue within the throat and wherein the first and second guide members cooperate to align the tongue with the first and second vehicles by the mating engagement of the first cam member with the third pocket and the second and third cam members with the first and second pockets; (g) lock means for locking the tongue in a fixed position relative to the tongue housing upon full engagement of the first and second guide members; and wherein the tongue is capable of lateral articulation when the tongue is not locked in the fixed position.  
       [0014] The cam members and the pockets may be rounded. The second guide member may pivot about either of the first pocket or the second pocket upon the retraction of the tongue from a laterally misaligned position. The bottom wall of the tongue housing may be the first guide member. The side walls of the tongue housing may be centrally rounded to define a generally hourglass shaped throat between the top and bottom walls.  
       [0015] The top wall of the tongue housing may define a first aperture therethrough and the tongue may define a second aperture therethrough in a location intermediate to the first and second ends of the tongue, the first and second apertures being aligned upon full engagement of the first and second guide members. The lock means may be a lock pin insertable through the first and second apertures. The bottom wall may also define a third aperture therethrough for insertion of the lock pin, the third aperture being aligned with the first aperture. The hitch may further comprise means for biasing the pin towards insertion into the first, second and third apertures. The means for biasing the pin towards insertion into first, second and third apertures may be a first spring on the lock pin, the first spring mounted between a top wall of a lock pin housing attached to the top wall of the tongue housing and a spring retaining member mounted on an intermediate portion of the lock pin, the top wall of the lock pin housing further comprising a fourth aperture for insertion of the lock pin, the fourth aperture being aligned with the first and third apertures and wherein the second aperture becomes aligned with the first, third and fourth apertures upon full engagement of the first and second guide members. The lock pin housing may comprise opposed, bevelled side walls.  
       [0016] The coupler may be selected from the group consisting of a clevis, a ring and a ball.  
       [0017] The coupler may be a clevis comprising: (a) an upper arm, the upper arm defining a first aperture therethrough; (b) a lower arm, the upper and lower arms being spaced apart by a vertical arm support wall, wherein the upper and lower arms define an opening facing away from the first vehicle for the insertion therein of a coupling means of the second vehicle; (c) a hitch pin insertable through the first aperture, the hitch pin being movable between a first, raised position and a second, lowered position, the hitch being capable of receiving the coupling means of the second vehicle when the hitch pin is in the first, raised position; (d) a release member extending above an upper surface of the horizontal upper arm and through a second aperture defined in the upper arm; (e) a hitch pin engaging member housed between a first shelf and a second shelf within the upper arm, the first shelf and the second shelf being on either side of the first aperture, the hitch pin engaging member defining a third aperture therethrough for accommodating the insertion of the hitch pin, a lower end of the release member contacting a first end of the hitch pin engaging member; (f) a second spring mounted within the first shelf, the second spring contacting the hitch pin engaging member, wherein the bias of the second spring maintains the hitch pin engaging member in an angled position to frictionally engage the hitch pin; and wherein application of downward force upon the release member causes the hitch pin engaging member to move to a substantially horizontal position against the bias of the second spring and frictionally disengage the hitch pin to permit upward vertical movement of the hitch pin within the first and third apertures.  
       [0018] The vertical arm support wall may abut the tongue housing upon full engagement of the first and second guide members.  
       [0019] The movement of the hitch pin from the first, raised position to the second, lowered position may be achieved through the application of downward force upon the hitch pin and wherein movement of the hitch pin from the second, lowered position to the first, raised position is achieved by lifting the hitch pin after the pin engaging member is frictionally disengaged from the hitch pin through the application of downward force upon the release member, causing the hitch pin engaging member to move to the substantially horizontal position.  
       [0020] The hitch pin may comprise a sleeve at its lower end and the upper arm may comprise a flange extending into the first aperture to define a radius smaller than the radius of the sleeve, so that the hitch pin cannot be fully withdrawn from the first aperture. The lower arm may define a fourth aperture aligned with the first aperture. A flange may extend into the fourth aperture to define a radius smaller than the radius of the sleeve so that the lower end of the hitch pin cannot extend through the lower arm of the clevis.  
       [0021] The hitch may comprise a first vertical wall substantially enclosing a forward end of the tongue housing and defining a slot therein, the slot having a width of at least the distance between the side walls of the tongue housing and having a height of at least the thickness of the tongue. The retaining means for preventing the tongue from being removed from the throat may comprise a trunnion extending through the tongue at a location proximal to the first end of the tongue, the trunnion having a height greater than the height of the slot in the vertical wall.  
       [0022] The hitch may comprise a first square tubing portion attached to and extending from the tongue housing towards the first vehicle, the first square tubing portion having means for attaching the first square tubing portion to a cooperating second square tubing portion attached to and extending from the vehicle.  
       [0023] The length of the top wall of the tongue housing may extend beyond the first end of the tongue when the tongue is in the fixed position.  
       [0024] The tongue housing may also comprise a second vertical wall for attaching the forward end of the tongue housing to the first vehicle, the second vertical wall being attached to and extending substantially perpendicular to the top wall of the tongue housing.  
       [0025] The tongue housing may also comprise a third side wall and fourth side wall, the third and fourth side walls being attached to and extending downwardly from the opposite forward side edges of the top wall.  
       [0026] The tongue housing may be wider at its forward end than at its rear end.  
       [0027] In accordance with another aspect of the invention, a hitch capable of coupling a first vehicle to a laterally misaligned second vehicle is disclosed. The hitch comprises: (a) a tongue housing for attaching to the first vehicle, the tongue housing comprising two spaced apart side walls defining a throat; (b) a first guide member attached to the housing, comprising: (i) a first cam member; (ii) a first pocket and a second pocket, the first and second pockets being located on either side of the first cam member; (c) a tongue having a first end and a second end, the tongue being extendable and retractable within the throat, the tongue having a width narrower than the distance between the two spaced apart side walls of the tongue housing; (d) a second guide member, coplanar with the first guide member and attached to the second end of the tongue, comprising: (i) a second cam member and a third cam member; (ii) a third pocket located between the second and third cam members; (e) a coupler attached to the second end of the tongue; wherein the first and second guide members become matingly engaged in an aligned, locked position upon the full retraction of the tongue within the throat from a laterally misaligned position; and wherein the tongue is guided from the laterally misaligned position into the aligned, locked position through the combination of: (i) the mating engagement of the first cam member with the third pocket and the second and third cam members with the first and second pockets; and (ii) the guided retraction of the tongue along at least one of the side walls of the tongue housing.  
       [0028] In accordance with another aspect of the invention, the bottom wall may also comprise a fourth pocket positioned opposite of the first cam member. In this case, the retaining means for preventing the tongue from being removed from the throat may comprise a trunnion attached to and extending below the tongue at a location proximal to the first end of the tongue, wherein the trunnion engages the fourth pocket upon full extension of the tongue.  
       [0029] The cam members and the pockets may be rounded. The bottom wall of the tongue housing may be the first guide member. The side walls of the tongue housing may be centrally rounded to define a generally hourglass shaped throat between the top and bottom walls.  
       [0030] The top wall of the tongue housing may define a first aperture therethrough and the tongue may define a second aperture therethrough in a location intermediate to the first and second ends of the tongue, the first and second apertures being aligned upon fall engagement of the first and second guide members. The lock means may be a lock pin insertable through the first and second apertures. The bottom wall may also define a third aperture therethrough for insertion of the lock pin, the third aperture being aligned with the first aperture. The hitch may firther comprise means for biasing the pin towards insertion into the first and second apertures. The means for biasing the pin towards insertion into first and second apertures may be a first spring on the lock pin, the first spring mounted between a top wall of a lock pin housing attached to the top wall of the tongue housing and a spring retaining member mounted on an intermediate portion of the lock pin, the top wall of the lock pin housing further comprising a third aperture for insertion of the lock pin, the third aperture being aligned with the first aperture and wherein the second aperture becomes aligned with the first and third apertures upon full engagement of the first and second guide members. The lock pin housing may comprise opposed, bevelled side walls.  
       [0031] The coupler may be selected from the group consisting of a clevis, a ring and a ball.  
       [0032] The coupler may be a clevis comprising: (a) an upper arm, the upper arm defining a first aperture therethrough; (b) a lower arm, the upper and lower arms being spaced apart by a vertical arm support wall, wherein the upper and lower arms define an opening facing away from the first vehicle for the insertion therein of a coupling means of the second vehicle; (c) a hitch pin insertable through the first aperture, the hitch pin being movable between a first, raised position and a second, lowered position, the hitch being capable of receiving the coupling means of the second vehicle when the hitch pin is in the first, raised position; (d) a release member extending above an upper surface of the horizontal upper arm and through a second aperture defined in the upper arm; (e) a hitch pin engaging member housed between a first shelf and a second shelf within the upper arm, the first shelf and the second shelf being on either side of the first aperture, the hitch pin engaging member defining a third aperture therethrough for accommodating the insertion of the hitch pin, a lower end of the release member contacting a first end of the hitch pin engaging member; (f) a second spring mounted within the first shelf, the second spring contacting the hitch pin engaging member, wherein the bias of the second spring maintains the hitch pin engaging member in an angled position to frictionally engage the hitch pin; and wherein application of downward force upon the release member causes the hitch pin engaging member to move to a substantially horizontal position against the bias of the second spring and frictionally disengage the hitch pin to permit upward vertical movement of the hitch pin within the first and third apertures.  
       [0033] The vertical arm support wall may abut the tongue housing upon full engagement of the first and second guide members.  
       [0034] The movement of the hitch pin from the first, raised position to the second, lowered position may be achieved through the application of downward force upon the hitch pin and wherein movement of the hitch pin from the second, lowered position to the first, raised position is achieved by lifting the hitch pin after the pin engaging member is frictionally disengaged from the hitch pin through the application of downward force upon the release member, causing the hitch pin engaging member to move to the substantially horizontal position.  
       [0035] The hitch pin may comprise a sleeve at its lower end and the upper arm may comprise a flange extending into the first aperture to define a radius smaller than the radius of the sleeve, so that the hitch pin cannot be fully withdrawn from the first aperture. The lower arm may define a fourth aperture aligned with the first aperture. A flange may extend into the fourth aperture to define a radius smaller than the radius of the sleeve so that the lower end of the hitch pin cannot extend through the lower arm of the clevis.  
       [0036] The hitch may comprise a first square tubing portion attached to and extending from the tongue housing towards the first vehicle, the first square tubing portion having means for attaching the first square tubing portion to a cooperating second square tubing portion attached to and extending from the vehicle.  
       [0037] The length of the top wall of the tongue housing may extend beyond the first end of the tongue when the tongue is in the fixed position.  
       [0038] The tongue housing may also comprise a second vertical wall for attaching the forward end of the tongue housing to the first vehicle, the second vertical wall being attached to and extending substantially perpendicular to the top wall of the tongue housing.  
       [0039] The tongue housing may also comprise a third side wall and fourth side wall, the third and fourth side walls being attached to and extending downwardly from the opposite forward side edges of the top wall.  
       [0040] The tongue housing may be wider at its forward end than at its rear end.  
       [0041] In accordance with another aspect of the invention, a hitch for coupling a towing vehicle to a trailer vehicle is disclosed. The hitch comprises: (a) a tongue housing for attaching to the towing vehicle, the tongue housing having a forward end and a rear end and comprising a top wall, a bottom wall spaced apart from the top wall by two spaced apart and centrally rounded side walls disposed therebetween and a vertical wall for attaching said forward end of said tongue housing to said towing vehicle, the vertical wall being attached to and extending substantially perpendicular to the top wall of the tongue housing, the top, bottom and side walls defining a throat, the throat having an open first end and an open second end and being generally hourglass shaped, the top wall defining a first aperture therethrough; (b) a tongue having a first end and a second end, the tongue being extendable and retractable within the throat, the tongue having a width narrower than the distance between the two spaced apart side walls, the tongue defining a third aperture therethrough in a position intermediate to the first and second ends of the tongue; (c) the bottom wall comprising a first guide member, the first guide member comprising: (i) a first rounded cam member; (ii) a first rounded pocket and a second rounded pocket, the first and second pockets being located on either side of the first cam member; and (iii) a fourth rounded pocket positioned opposite of the first rounded cam member; (d) a trunnion attached to and extending below the tongue at a location proximal to the first end of the tongue, wherein the trunnion engages the third pocket upon full extension of the tongue; (e) a second guide member, coplanar with the first guide member and attached to the second end of the tongue, the second guide member comprising: (i) a second rounded cam member and a third rounded cam member; (ii) a third rounded pocket located between the second and third cam members; (f) a coupler attached to second end of the tongue; wherein the second guide member is matingly received by the first guide member upon retraction of the tongue within the throat and wherein the first and second guide members cooperate to align the tongue with the towing and trailer vehicles by the mating engagement of the first cam member with the third pocket and the second and third cam members with the first and second pockets; (g) a lock pin housing attached to the top wall of the tongue housing, the lock pin housing comprising a top wall and two opposed side walls, the top wall of the lock pin housing defining a third aperture therethrough, the aperture being aligned with the third aperture; (h) a lock pin insertable through the first, second and third apertures; (i) a spring mounted on the lock pin between the top wall of the lock pin housing and a spring retaining member mounted on an intermediate portion of the lock pin, the spring biasing the lock pin towards insertion into the first, second and third apertures; wherein: k) when the first, second and third apertures become aligned upon full reception of second guide member by the first guide member the lock pin is inserted into the first, second and third apertures to lock the tongue in a fixed position relative to the housing; (k) the tongue is capable of lateral articulation when the tongue is not locked in the fixed position; and (1) the length of the top wall of the tongue housing extends beyond the first end of the tongue when the tongue is in the fixed position. 
     
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
     [0042] In the drawings which illustrate specific embodiments of the invention, but which should not be construed as restricting the spirit or scope of the invention in any way:  
     [0043]FIG. 1 is a perspective view of an embodiment of the hitch of the present invention illustrating its tongue in a retracted, locked position;  
     [0044]FIG. 2 is a perspective view of the hitch of FIG. 1 illustrating its tongue in an extended, unlocked position;  
     [0045]FIG. 3 is a perspective view of the tongue of the hitch of FIG. 1;  
     [0046]FIG. 4 is a bottom perspective view of the tongue housing of the hitch of FIG. 1 illustrating the side walls of the throat in dotted outline;  
     [0047]FIG. 5 is a partial cross-section view taken along line  5 - 5  of FIG. 1 illustrating the insertion of the lock pin through the apertures in the tongue, tongue housing and lock pin housing;  
     [0048]FIG. 6 is a partial cross-section view taken along line  6 - 6  of FIG. 3 illustrating the hitch pin in a slightly lowered position as compared to FIG. 3;  
     [0049] FIGS.  7 - 10  are bottom views illustrating the guided movement of the tongue from an extended, laterally misaligned position to a retracted, aligned and locked position;  
     [0050]FIG. 11 is a perspective view of a first alternative embodiment of the coupler illustrated in FIG. 3;  
     [0051]FIG. 12 is a perspective view of a second alternative embodiment of the coupler illustrated in FIG. 3;  
     [0052]FIG. 13 is a perspective view of a first alternative embodiment of the hitch of FIG. 1;  
     [0053]FIG. 14 is a perspective view of the hitch of FIG. 1 mounted to a towing vehicle;  
     [0054]FIG. 15 is a perspective, exploded view of the hitch of FIG. 13 with a ball coupler.  
     [0055]FIG. 16 is a perspective view of third alternative embodiment of the hitch of the invention;  
     [0056]FIGS. 17 and 18 are perspective views of prior art “E” type hitches;  
     [0057]FIG. 19 is a perspective view of the hitch of FIG. 16 mounted to an airport pallet or container carrier;  
     [0058]FIG. 20 is a perspective view of the hitch of FIG. 16 mounted to an airport freight vehicle;  
     [0059]FIG. 21 is a bottom view of the hitch of the invention with an alternative embodiment of the bottom wall of the tongue housing and illustrating its tongue in an extended, laterally misaligned position;  
     [0060]FIG. 22 is a bottom view of the hitch of FIG. 21 illustrating its tongue in a retracted, aligned and locked position;  
     [0061]FIG. 23 is a perspective view of the hitch of the invention with an alternative embodiment of the tongue housing and illustrating its tongue in an extended position; and  
     [0062]FIG. 24 is a bottom view of the hitch of FIG. 23 illustrating the tongue in a retracted, aligned and locked position. 
    
    
     DESCRIPTION  
     [0063] The hitch of the present invention allows the coupling of a towing vehicle to a trailer vehicle and is particularly suited for situations where there is imprecise alignment of the coupling means of the two vehicles. As used herein, the term “towing vehicle” encompasses any vehicle for pulling, towing or otherwise drawing a subsequent vehicle, referred to as a “trailer vehicle”, coupled therewith. For example, a towing vehicle could be a truck, an RV, a car or a tractor vehicle used at airports for pulling freight (i.e. luggage, etc.) carts. The term “trailer vehicle”, on the other hand, encompasses any vehicle which is designed to be pulled, towed or otherwise drawn by a towing vehicle. For example, a towing vehicle could be a boat trailer, an airport freight cart or an airport pallet or container cart. As will be explained later, “towing vehicle” also encompasses a first trailer vehicle which is used to tow a second trailer vehicle in a multiple trailer vehicle train.  
     [0064]FIG. 1 illustrates a hitch  10 , which includes a tongue housing  12  and a tongue  14 . Tongue housing  12  is adapted for attachment to a rear end of a towing vehicle, such as, for example, a tractor for pulling freight carts at airports.  
     [0065] Turning to FIG. 4 in conjunction with FIG. 1, tongue housing  12  includes a top wall  16  and a bottom wall  18 , which are in a substantially parallel relationship and which are spaced apart by a distance at least as great as the thickness of tongue  14 . Spaced apart side walls  20 ,  22  are disposed between top wall  16  and bottom wall  18 . Together, top wall  16 , bottom wall  18  and side walls  20 ,  22  form a throat  23 . Side walls  20  and  22  are spaced apart such a distance that throat  23  has a width greater than the width of tongue  14 , thus allowing for lateral articulation of tongue  14 . Referring to FIGS. 4, 7 and  8 , side walls  20 ,  22  have rounded central portions  20   a  and  22   a  (illustrated in dotted outline in FIG. 8) so that throat  23  is generally hourglass shaped. A vertical wall  24  substantially encloses housing  12  at its forward end  12   a.  Vertical wall  24  abuts the forward ends of each of top wall  16 , bottom wall  18  and side walls  20 ,  22 . Vertical wall  24  has a horizontal slot  26  defined therein, which permits the slidable extension and retraction of tongue  14  within tongue housing  12 . FIG. 5 illustrates the width of slot  26  between central rounded portions  20   a  and  20   b  of side walls  20  and  22 . It will be appreciated that slot  26  widens at the forward opening of throat  23 , as with the illustrated rear opening of throat  23  in FIG. 4.  
     [0066] Referring to FIG. 14, vertical wall  24  may conveniently be welded or fastened (such as by bolting) to a vertical surface  25  on the rear end of a towing vehicle  27  to attach tongue housing  12 , and ultimately hitch  10 , to towing vehicle  27 . It will be appreciated by those skilled in the art that the attachment of hitch  10  via vertical walls  24  and  25  is optional and tongue housing  12  could alternatively be attached to towing vehicle  27  in any suitable manner, such as for example, by welding or fastening bottom wall  18  to a horizontal skirt  29  of a standard vehicle commercial bumper. Hitch  10  can thus be easily retrofitted to existing towing vehicles.  
     [0067] For proper operation of hitch  10 , housing  12  must be attached to towing vehicle  27  so that tongue  14  is capable of extension and retraction without engaging rear wall  25 . This may require, for example, attaching hitch  10  so that slot  26  is slightly below the lower-most edge of the rear end of rear wall  25 . Alternatively, a slot (not shown) could be cut from a rear wall  25  of the towing vehicle at a location aligned with slot  26  to accommodate the insertion of tongue  14  therethrough.  
     [0068] Turning to FIG. 3, tongue  14  has a first end  28 , and a second end  30 . Tongue  14  is extendable, retractable and capable of lateral articulation within throat  23 . As used herein, the term “extendable” refers to the movement of extending second end  30  of tongue  14  away from tongue housing  12 . For example, tongue  14  is illustrated in an extended position in FIG. 2 relative to the position shown in FIG. 1. The term “retractable”, on the other hand, refers to the movement of retracting second end  30  of tongue  14  from an extended position towards tongue housing  12 . FIG. 1 illustrates tongue  14  in its fully retracted position.  
     [0069] Tongue  14  includes a trunnion  32 , in a location proximal to first end  28 . Trunnion  32  extends vertically above and below (see FIG. 7 for an illustration of the extension of trunnion  32  below tongue  14 ) tongue  14  and has a height greater than the height of slot  26 . Trunnion  32  is thus able to retain first end  28  from being fully removed from housing  12  upon extension of tongue  14  (see FIG. 7), and simultaneously permits second end  30  to articulate laterally, relative to first end  28 , when tongue  14  is fully extended, so as to allow hitch  10  to couple towing vehicle  27  to an imprecisely aligned trailer vehicle (not shown).  
     [0070] Tongue  14  has a clevis  36  at its second end  30  for coupling to a cooperating coupler (not shown) operatively secured to the trailer vehicle (not shown). Clevis  36  has a lower arm  38 , an upper arm  40 , supported by vertical arm support wall  42 , and a hitch pin  44 . As illustrated in FIG. 6, hitch pin  44  is insertable through an aperture  46  in upper arm  40  and partially insertable into aperture  48  in lower arm  38 . Clevis  36  further includes a release member  92 , having its upper end  92   a  extending through aperture  93  above an upper surface  40   a  of upper arm  40 , and its lower end  92   b  in contact with pin engaging member  94 . End  92   b  is shaped to a size larger than aperture  93  so that release member  92  cannot be upwardly withdrawn from upper arm  40  through aperture  93 . Pin engaging member  94  has a first end  94   a  and a second end  94   b.  First end  94   a  is in contact with spring  96  and release member  92 . Pin engaging member  94  is disposed in shelves  98  and  100  within upper arm  40 . Pin engaging member  94  has an aperture  99  intermediate to ends  94   a  and  94   b  to accommodate the insertion of hitch pin  44  therethrough. End  94   b  of pin engaging member  94  rests within shelf  100 . A lower end of spring  96  is mounted into sunken portion  98   a  of shelf  98 .  
     [0071] In operation, hitch pin  44  is normally in a raised position, illustrated in FIG. 1, so that it is possible to position a corresponding ring (not shown) of a trailer vehicle (not shown) within clevis  36  (between arms  38  and  40 ) so that coupling can occur with the downward insertion of hitch pin  44  through the ring. Hitch pin  44  is maintained in its raised position by pin engaging member  94 . Specifically, when pin engaging member  94  is in an angled position, as illustrated in FIG. 6, there is frictional engagement between an inside edge of pin engaging member  94  (surrounding aperture  99 ) with the shaft of hitch pin  44  so that hitch pin  44  is maintained in its raised position. Grooves  102  assist in this frictional engagement. When a ring (not shown) is positioned in the clevis between arms  38  and  40 , an operator can readily insert hitch pin  44  through the ring (not shown) by applying a downward force on hitch pin  44 . This downward force will cause pin engaging member  94  to move to a substantially horizontal position, against the bias of spring  96 , so that the shaft of hitch pin  44  frictionally disengages pin engaging member  94 , allowing free vertical movement of hitch pin  44 . Once hitch pin  44  is inserted downwardly through the ring (not shown) and the downward force ceases, the bias of spring  96  causes pin engaging member to return to its angled position of FIG. 6, again frictionally engaging hitch pin  44  to maintain it in the lowered position. This prevents hitch pin  44  from inadvertently lifting so as to de-couple the trailer vehicle&#39;s coupling ring (not shown). Again, grooves  102  assist in the frictional engagement. When de-coupling is desired, the operator applies a downward force to the upper end  92   a  of release member  92  causing end  94   a  of pin engaging member  94  to move downwardly so that pin engaging member  94  moves to a substantially horizontal position so that the internal edge of pin engaging member  94  (surrounding aperture  99 ) frictionally disengages hitch pin  44 , allowing vertical upward movement of hitch pin  44  for de-coupling.  
     [0072] Clevis  36  thus allows for the easy and safe coupling and decoupling of a ring or other coupling means on the trailer vehicle. Coupling is achieved in a straightforward motion by the application of downward force on hitch pin  44 . However, clevis  36 , and specifically pin engaging member  94 , also increase the safety of the entire operation by locking the ring (not shown) in place, thus minimizing the prospects that inadvertent de-coupling will take place at an inopportune time or place.  
     [0073] Hitch pin  44  is fitted with a sleeve  104  at its lower end, which in combination with flange  106  on upper arm  40 , prevents the upward removal of hitch pin  44  from clevis  36 . Flange  106  extends into aperture  46  to define a smaller radius than sleeve  104 . Thus, vertical sliding of pin  44  in aperture  46  is possible, but complete removal of pin  44  is prevented. Flange  108  within aperture  48  of lower arm  38  acts in a similar manner to prevent hitch pin  44  from being lowered to a position below lower arm  38 , where it would be vulnerable to inadvertent contact by extraneous objects.  
     [0074] Second end  30  of tongue  14  has attached on its underside a guide member  50 . Guide member  50  may be welded (or otherwise fastened) to second end  30  or tongue  14  may be configured so that guide member  50  is integral with it. As illustrated in FIG. 7, guide member  50  is “Y-shaped” and comprises rounded cam members  52 ,  54  which extend away from one another in a diverging relationship to define a central, rounded pocket  56 , which generally faces towards tongue housing  12 . An aperture  90  is located on tongue  14  in a location intermediate to first end  28  and second end  30 , near to pocket  56 .  
     [0075] Turning to FIGS. 4 and 7, bottom wall  18  of housing  12  comprises a “W-shaped” guide member  60 , which in operation matingly receives guide member  50  upon retraction of tongue  14  within housing  12 . To accommodate this mating reception, guide members  50  and  60  are coplanar with one another. Guide member  60  comprises rounded central cam member  62  and adjacent rounded pockets  64 ,  66 , which generally face a direction away from tongue housing  12 . Outside edges  68 , 70  flare outwardly from pockets  64 , 66 , respectively. As will be appreciated by those skilled in the art, bottom wall  18  need not necessarily comprise guide member  60 . Rather, these could be separate elements whereby bottom wall  18  is identical in shape to top wall  16  and guide member  60  was attached to the underside of that embodiment of bottom wall  18  (it will be understood that in such an arrangement, guide member  50  would be similarly modified so that it remained coplanar with guide member  60 ). However, bottom wall  18  and guide member  60  are described herein as one integral element.  
     [0076] Referring to FIGS. 1 and 5, lock pin housing  72  is attached on the upper surface of top wall  16  of housing  12 . Lock pin housing  72  comprises bevelled side walls  74 ,  76  and a top wall  78 . The bevelled shape of side walls  74 ,  76  acts to deflect any inadvertent blows to hitch  10 . Housing  72  houses lock pin  80 , which is biased downwardly by spring  83 . Spring  83  is coiled around a vertical shaft  84  of lock pin  80  and between top wall  78  and spring retaining member  82 , maintained on shaft  84  by notch  85 , which extends through shaft  84 . Lock pin  80  is insertable through apertures  86 ,  88 ,  90  and  91 , found respectively in top wall  78 , top wall  16 , tongue  14  and bottom wall  18  (see FIG. 5). When lock pin  80  is inserted through aligned apertures  86 ,  88 ,  90  and  91 , tongue  14  is “locked” in a fixed axial and lateral position relative to tongue housing  12 .  
     [0077] Hitch  10  operates in the following manner. Towing vehicle  27 , having hitch  10  attached to its rear end as described above and illustrated in FIG. 14, is positioned near to the forward end of a trailer vehicle (not shown). At this time, tongue  14  is in its “locked” position of FIG. 1 (i.e. guide members  50  and  60  are matingly received and lock pin  80  is inserted through apertures  86 ,  88 ,  90  and  91 ). In order to couple hitch  10  to the trailer vehicle (not shown), lock pin  80  is lifted upwardly against the bias of spring  83  and withdrawn from apertures  91  and  90 , of bottom wall  18  and tongue  14 , respectively. Lock pin  80  is not, however, removed from apertures  86  and  88 . Tongue  14  is then extended from throat  23  and manually positioned so that clevis  36  can be coupled to a cooperating coupling means (not shown) provided on a trailer vehicle or alternatively on a draw bar (not shown) attached to the forward end of a trailer vehicle (not shown). This “unlocking” and coupling action is achieved in a straight-forward and timely manner, allowing hitch  10  to be used repeatedly and efficiently by an operator over a period of time. This simple, yet reliable action may be particularly advantageous for coupling an airport tractor to a freight cart, which is done repeatedly and continuously by airport employees during the course of a day.  
     [0078] Tongue  14  is capable of extension until trunnion  32  engages vertical wall  24  immediately surrounding slot  26 . This defines the length of the axial extension of tongue  14 . Lateral articulation of tongue  14  is possible to couple imprecisely aligned towing and trailer vehicles. Specifically, tongue  14  is free to articulate laterally, subject only to the lateral constraints of side walls  20 ,  22  within throat  23 , as soon as lock pin  80  is raised from apertures  91  and  90 . Very little, if any, axial extension of tongue  14  is required for lateral articulation to be possible, thus permitting coupling of misaligned vehicles which are in very close proximity to one another. When tongue  14  is fully extended, trunnion  32  engages vertical wall  24  of housing  12  as described above and provides a point at which second end  30  of tongue  14  can pivot relative to first end  28 . This is illustrated by arrow  7  and the phantom outline of tongue  14  and guide member  50  in FIG. 7.  
     [0079] Whenever tongue  14  is not in its “locked position” of FIG. 1, lock pin  80  will be downwardly biased by spring  82  so that it rides along the top surface  14   a  of tongue  14 .  
     [0080] After tongue  14  is manually positioned (axially and/or laterally), clevis  36  can then be coupled to cooperating coupling means, such as a ring (not shown). As explained above, this is accomplished by inserting downward force on hitch pin  44  causing it to be inserted through the ring (not shown). Hitch pin  44  can be downwardly inserted from its position in FIG. 1, through a ring member (not shown), until its lower end is at least partially within aperture  48 . Pin engaging member  94 , through the bias of spring  96 , returns to its angled position of FIG. 6, frictionally engaging hitch pin  44  and thus preventing any vertical movement of the hitch pin  44  which would allow the inadvertent de-coupling of the ring member (not shown). Grooves  102  assist in this “locking” of hitch pin  44 .  
     [0081] Once this coupling takes place, the towing vehicle  27  is advanced in a forward direction. Very shortly thereafter, the brakes of the towing vehicle  27  are applied. As a result of applying the brakes, the forward inertia of the trailer vehicle (not shown) will cause tongue  14  to retract from an extended position and slide further into throat  23 . If the towing and trailer vehicles are precisely aligned upon coupling, this retraction takes place in a simple manner until guide members  50  and  60  matingly engage and lock pin  80  falls through apertures  91  and  90  when aperture  90  becomes aligned with apertures  86 ,  88  and  91 .  
     [0082] If, however, the towing and trailer vehicles are imprecisely aligned upon coupling, the smooth guided movement of tongue  14  into its locked position of FIG. 2 is achieved through: (1) the interaction of guide members  50  and  60 , and specifically, the mating reception of cam members  52 ,  54  and  62  and pockets  64 , 66  and  56 ; and (2) the interaction of tongue  14  with side walls  20  and  22 . FIGS.  7 - 10  illustrate this progression.  
     [0083] Turning to FIG. 7, tongue  14  is illustrated in an extended, laterally misaligned position. The shape of throat  23  permits tongue  14  to be laterally articulated to a large degree, as illustrated in FIG. 7, though it is possible to modify hitch  10  so that the articulation range can meet various operational requirements. This wide range of lateral articulation is advantageous because it permits hitch  10  to couple towing and trailer vehicles from misaligned positions that might not be possible with prior art hitches. Additionally, it permits the movement of tongue  14  to its locked position from any number of laterally misaligned positions.  
     [0084] Following coupling to the coupling means on a trailer vehicle (not shown), the forward inertia of the trailer vehicle (achieved as described above) causes tongue  14  to retract further into throat  23 , as illustrated in FIG. 8. During this retraction, an outer edge  54   a  of cam member  54  engages outside edge  70  of guide member  60 . Continued retraction of tongue  14  into throat  23  pulls cam member  54  into engagement with pocket  66  of guide member  60  (see FIG. 9). Guide member  50  then pivots about a rounded front portion  54   b  of cam member  54  and into alignment with guide member  60  as follows. Pocket  56  engages cam member  62  of guide member  60 . Cam member  52  then falls into place, first upon the engagement of its inner edge  52   c  with cam member  62 , and second, upon further retraction of tongue  14 , by the engagement of a rounded front portion  52   b  with rounded pocket  64  of guide member  60 . When cam members  52 ,  54  and  62  are fully received by pockets  64 ,  66  and  56 , respectively, aperture  90  becomes fully aligned with apertures  86 ,  88  and  91 , allowing lock pin  80  to be inserted therethrough by the downward bias of spring  83 , thus moving hitch  10  to its “locked” position, illustrated in FIG. 10. Hitch  10  is “locked” in that tongue  14  is fixed, laterally and longitudinally, relative to tongue housing  12 . As illustrated in FIGS.  7 - 10 , hitch  10  is thus self-aligning in that it operates to facilitate alignment of towing and trailer vehicles.  
     [0085] The progression of tongue  14  from its position in FIG. 7 to its position in FIG. 10 is achieved not only by the mating engagement of coplanar guide members  50  and  60 , but also through the interaction of tongue  14  with side walls  20  and  22 . Referring to FIG. 7, the opposite side edges of tongue  14 , upon retraction, are slidably engaged by a rear edge  20   b  of side wall  20  and a front edge  22   c  of side wall  22 . The sliding engagement of tongue  14  within and into throat  23  helps with the smooth, guided movement of tongue  14  from its most laterally articulated position (FIG. 7) into its locked, aligned and filly retracted position (FIG. 10). It will be appreciated that tongue  14  may be slidably engaged by only one of side walls  20  and  22  from laterally misaligned positions between its lateral articulation range, illustrated in FIG. 7.  
     [0086] Once tongue  14  moves into its locked position of FIG. 10, the operator is thus free to move the towing vehicle-trailer vehicle train to its destination. The mating engagement of guide members  50  and  60 , as well as the abutment of vertical arm support wall  42  with tongue housing  12  and lock pin housing  72 , causes hitch  10  to have a sturdy construction in its locked position. This sturdy construction minimizes the possibility of damage occurring to hitch  10  upon any inadvertent collisions involving the towing or trailer vehicles when hitch  10  is in use.  
     [0087] It will be appreciated that the engagement of guide members  50  and  60  can occur in the opposite manner as described above. That is, the imprecise alignment of the vehicles may occur in such a manner that it is cam member  52  of guide member  50  which first engages pocket  64  of guide member  60  and then guide member  50  is pivoted until cam member  54  engages pocket  66 . This would occur, for example, from the laterally misaligned position as shown in phantom outline in FIG. 7. It will also be appreciated that tongue  14  can move from any number of laterally misaligned positions within the lateral articulation range of tongue  14  illustrated in Figure  7  to its locked position, depending upon the positions of the towing and trailer vehicles.  
     [0088] It will also be appreciated that the arrangement of hitch  10  helps to overcome the previously-discussed problems that prior art hitch assemblies may suffer from. The rounded edges of cam members  52 ,  54  and  62  and pockets  64 ,  66 ,  56 , as well as the interaction of tongue  14  with side walls  20  and  22  in throat  23 , allow for the smooth, guided transition of tongue  14  from an extended, misaligned position to its locked position. Because of this arrangement of hitch  10 , it is not necessary to first align the vehicles before applying the brakes, as it is with some prior art hitches. Rather, the arrangement of hitch  10  allows for the self-alignment of tongue  14  with housing  12  upon the forward inertia of tongue  14  from any number of laterally misaligned positions. This is advantageous in situations where the operator is faced with limited room to operate, thus limiting the ability to move the towing vehicle-trailer vehicle train into aligned arrangement before locking the hitch.  
     [0089] As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. For example, clevis  36  could be replaced with a ring  110  or a ball  112 , illustrated respectively in FIGS. 11 and 12, or any other suitable means for coupling hitch  10  to a trailer vehicle (not shown). Similarly, hitch  10  could be modified as illustrated in FIG. 13 so that the attachment of housing  12  to the towing vehicle  27  could be accomplished by the engagement of square tubing portion  114  with corresponding square tubing portion  116 , mounted on the underside of a towing vehicle (not shown). Pin  118  is insertable through apertures  114   a  and  116   a  on portions  114  and  116  to maintain portion  114  within portion  116 , thus attaching hitch  10  to the towing vehicle  27 . In the embodiment of the hitch illustrated in FIG. 13, square tubing portion  114  would thus replace lock pin housing  72  from the previously discussed embodiment and would be attached to tongue housing  12  by means of welding or the like to a top surface  16   a  of top wall  16 . FIG. 15 illustrates this embodiment of the hitch in association with a towing vehicle  27 . In FIG. 15, clevis  36  has been replaced with ball  112 .  
     [0090] Similarly, it is within the inventive scope herein to utilize hitch  10  not only on the rear of towing vehicle  27 , but also on the rear of a trailer vehicle (not shown) where more than one trailer vehicle (not shown) will be pulled by the same towing vehicle. In theory, each trailer vehicle in a multiple trailer vehicle train could be fitted on its rear end with hitch  10  for coupling to a following trailing trailer.  
     [0091] Similarly, it is within the inventive scope of the invention to attach hitch  10  to the front of a trailer vehicle, rather than to a rear surface of towing vehicle  27 . In such an embodiment, tongue  14  would thus extend (after pin  80  is unlocked) away from the trailer vehicle (not shown) and towards towing vehicle  27  for coupling to a coupler attached to the rear of towing vehicle  27 . In such an embodiment, it would be guide member  60  which would matingly engage guide member  50  upon the forward inertia of the trailer vehicle (not shown), rather than the opposite as described above.  
     [0092] Similarly, it would also be possible to modify hitch  10  for use as an intermediate between vehicles having already-installed coupling means. That is, housing  12  could be fitted with a coupling means (not shown) for coupling to coupling means (not shown) attached to a rear end of a towing vehicle. Clevis  36  could then be used to couple to corresponding coupling means (not shown) at the front of a trailer vehicle (not shown) and the operation of hitch  10  would remain the same as described above, except that hitch  10  would be releasably coupled to both the towing vehicle and the trailer vehicle.  
     [0093] Similarly, it is within the inventive scope of the invention to modify the length of tongue  14 , if the need arises.  
     [0094] The elements of hitch  10  are preferably constructed of a durable steel material, though it will be appreciated that this is not required for operation of hitch  10 . Tongue housing  12  and clevis  36  have both been illustrated herein as being of a cast construction. Alternatively, these elements could be constructed of multiple layered, horizontal plates which are fastened (by bolting, welding or any other suitable means) together.  
     [0095] Those skilled in the art will appreciate that the clevis of the invention could be attached directly to a vehicle, apart from hitch  10  as described, for use in coupling other vehicles. This embodiment of the invention is illustrated in FIG. 16.  
     [0096] Hitch  120  is comprised of clevis  136 , which is identical in structure and operation to clevis  36  described above and illustrated in FIGS.  1 - 3 ,  6 ,  13  and  14  except that clevis upper arm  140  is illustrated as being constructed from horizontal plates  140   a,    140   b  and  140   c.  Plate  140   a  is integral with vertical arm support wall  142 . Plates  140   a,    140   b  and  140   c  are fastened together by any suitable means (such as welding or bolts). Upper arm  140  could also be of a cast construction, as illustrated for upper arm  40  of clevis  36  in FIG. 6.  
     [0097] Hitch  120  also comprises wall  146 , attached to forward portions of upper arm  140 , lower arm  138  and vertical arm support wall  142 . Wall  146  may be conveniently be bolted (through apertures  148  and  149 ) to an airport freight vehicle  150 , as illustrated in FIG. 20, an airport pallet or container carrier  152 , as illustrated in FIG. 19, or to any other towing or trailer vehicle. Wall  146  could alternatively be attached by welding to the towing or trailer vehicle.  
     [0098]FIGS. 17 and 18 illustrate prior art “E” type hitches, which are in common use on airport carts and carriers. Some “E” type hitches, such as hitch  160  illustrated in FIG. 17, do not include any mechanism to lock the hitch pin in a lowered position, other than the bias of a spring  162  (when notch  164  is rotated to disengage locking member  166 , and the hitch pin is lowered). This is disadvantageous since inadvertent de-coupling can occur if the spring malfunctions and the hitch pin rises, allowing the trailer vehicle&#39;s coupling means to be released from hitch  160 . Other “E” type hitches, such as hitch  170 , illustrated in FIG. 18, include a slotted spring plate  172  that prevents upward or downward movement of the hitch pin from its lowered or raised positions, respectively, unless slot  174  is aligned with locking member  176 . The “E” hitch illustrated in FIG. 18 is, however, disadvantageous because the unlocking of the hitch can be difficult when the operator is in a hurry. Slot  174  can easily become misaligned relative to locking member  176  so that the operator will be forced to see or manually feel for the alignment of slot  174  and locking member  176 , something which may be difficult in dark conditions or inclement weather. Further, “E” type hitches often have a “high” profile so that when used on airport freight vehicles they can interfere with the loading and unloading of the freight vehicles when the hitch pin is inadvertently left in its raised position.  
     [0099] Hitch  120  overcomes these disadvantages by providing a low profile, easy to manufacture hitch which automatically locks its hitch pin in both its lowered and raised positions, thus increasing the safety of the entire operation. Hitch  120  is also easy and quick to operate.  
     [0100]FIGS. 21 and 22 illustrate a hitch  210  having an alternative embodiment of the bottom wall described above and illustrated in FIGS. 4 and 7- 10 .  
     [0101] In contrast to bottom wall  18  (of hitch  10 ), hitch  210  differs in that bottom wall  218  includes a rounded pocked  219  and two edges  221 , 223  adjacent thereto which flare outwardly from one another in a diverging relationship. Rounded pocket  219  faces a direction opposite of rounded pockets  264 ,  266  and is located opposite of rounded central cam member  262 . It will be appreciated by those skilled in the art that the recess in bottom wall  218  forming rounded pocket  219  results in a different shape for the slot (not shown) of vertical wall  224 , as compared to slot  26  defined in vertical wall  24  of hitch  10 .  
     [0102] As illustrated in FIG. 21, first end  228  of tongue  214  is capable of being extended into tongue housing  212  when tongue  214  is fully extended. This differs from hitch  10  where first end  28  of tongue  14  is not capable of being extended into tongue housing  12  due to the engagement of trunnion  32  against vertical wall  24  (see FIG. 7). To accommodate this extension for hitch  210 , trunnion  232  on tongue  214  extends only vertically below tongue  214  and does not extend vertically above tongue  214  as trunnion  32  does above tongue  14  with hitch  10 . As a result, tongue  214  is capable of being extended until trunnion  232  engages rounded pocket  219 , as illustrated in FIG. 21, thus providing additional extension of tongue  214  in comparison to tongue  14  of hitch  10  (see FIG. 7). Tongue  214  is prevented from being removed from the throat of hitch  210  by the engagement of trunnion  232  and rounded pocket  219 . Rounded pocket  219  also provides a pivot point for tongue  214  to articulate from when tongue  214  is fully extended and hitch  210  is used to couple two laterally misaligned vehicles.  
     [0103] Bottom wall  218  of hitch  210  does not have an aperture corresponding to aperture  91  in bottom wall  18  of hitch  10 . Rounded pocket  219  is aligned with apertures (not shown) in top wall  216  (corresponding to aperture  88  in top wall  16  of hitch  10 ) and in the top wall of the lock pin housing (corresponding to aperture  86  in top wall  76  of lock pin housing  72  of hitch  10 ). A lock pin  280  (corresponding to lock pin  80  of hitch  10 ) locks tongue  214  into the fully retracted, locked position of FIG. 22 upon the alignment of the aperture  290  in tongue  214  (corresponding to aperture  90  in tongue  14 ) and the apertures in top wall  216  and the top wall of the lock pin housing (not shown).  
     [0104] Hitch  210  is otherwise identical to hitch  10  in terms of structure and operation.  
     [0105]FIGS. 23 and 24 illustrate a hitch  310  having an alternative embodiment of the tongue housing described above and illustrated in FIG. 1. Tongue housing  312  allows hitch  310  to be attached to a towing (or trailer) vehicle without the tongue  314  being inserted through (as in FIG. 14) or underneath the rear surface of the vehicle. Tongue housing  312  has been modified to accommodate the entire retraction range of tongue  314  therein.  
     [0106] Tongue housing  312  includes a top wall  316 , a bottom wall  318 , two spaced apart side walls  320 ,  322  and a vertical wall  324 .  
     [0107] Bottom wall  318 , as illustrated in FIG. 24, is configured like bottom wall  218  (in that it includes a rounded pocket  319  like rounded pocket  218 ) except that the outward side edges  318   a  and  318   b  flare outwardly in a diverging relationship. It will be appreciated that bottom wall  318  could alternatively be configured similar to bottom wall  18  (i.e. not including a rounded pocket  319 ), rather than bottom wall  218 .  
     [0108] Side walls  320 , 322  are identical to side walls  20 , 22  of hitch  10  with the similar exception that the outward side edges thereof flare outwardly in a diverging relationship similar to outside edges  318   a  and  318   b  of bottom wall  318 .  
     [0109] Top wall  316  differs from top wall  16  in that it extends a length greater than the length of tongue  214 , until it attaches to vertically-extending wall  324 . That is, top wall  316  extends beyond first end  328  of tongue  314  when tongue  314  is in its locked position, as illustrated in FIG. 24. The outward side edges of top wall  316  flare away from one another in a diverging relationship like bottom wall  318  and side walls  320 , 322 . Lower side walls  325 ,  327  are attached at the lower, forward edges of top wall  316  and extend downwardly to the depth of bottom wall  318 . Tongue housing  312  is thus fan-shaped (in that forward end  312   a  of tongue housing  312  is wider than rear end  312   b ) and defines an interior cavity between side walls  325 ,  327  to accommodate the retraction of tongue  314  from laterally misaligned positions.  
     [0110] Tongue housing  312  does not include a vertical wall similar to vertical wall  24  as in hitch  10 .  
     [0111] Lock pin housing  372  is not illustrated in FIG. 23 with bevelled side walls (as with housing  72  of hitch  10 ), though it will be appreciated that such a modification could readily be made.  
     [0112] Tongue housing  312  may also include a bracket  329  for storage of a chain.  
     [0113] Tongue housing  312  is attached to a vertical surface of a towing (or trailer) vehicle by attaching vertical wall  324  thereto by welding, or any other suitable fastening means (e.g. bolting, etc.). The full range of motion of first end  328  of tongue  314  is thus within tongue housing  312  and it is not necessary to insert tongue  314  through or underneath the rear wall of the vehicle.  
     [0114] Otherwise, hitch  310  is identical in operation to hitch  10  and hitch  210  as described above.  
     [0115] Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.