Abstract:
A coupling device for coupling a corner casting of a first freight container to a corner casting of a second freight container including a fully automatic latching lock providing consistent and repeatable release force characteristics. The coupling device preferably includes a positive stop which resists rolling of stacked containers at onset.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a container coupling device and, more particularly, to a container coupling device including a fully automatic latching lock providing consistent and repeatable release force characteristics. 
     As will be recognized by those skilled in the art, freight containers are commonly used for transporting cargo by ship and/or rail. These freight containers are generally rectangular and are dimensioned within standardized ranges used throughout the shipping industry. The containers generally include rigid corner castings of standardized size which allow the containers to be vertically and/or horizontally stacked, and thereafter locked to one another. More particularly, the corner castings include elongated or circular openings dimensioned and configured to accept locking devices, e.g., manually operated coupling devices, which allow adjacent corner castings of adjacent containers to be positively locked to one another. 
     Manually operated coupling devices are well known in the art. Certain known manually operated devices are disclosed in U.S. Pat. Nos. 4,212,251, 4,082,052, and 3,894,493. As will be appreciated by those skilled in the art, these coupling devices are operable between a first position wherein the device is oriented to allow coupling of adjacent corner castings, and a second position wherein the device is oriented to positively lock the adjacent corner castings to one another. In many such devices, the device includes a manually operated lever which is used to move the locking element of the coupling device between a first unlocked position and a second locked position. 
     In certain applications, it is not convenient and/or desirable to use manually operated coupling devices. For example, when transporting freight containers by rail, the industry often utilizes coupling devices having at least one fully automatic latching lock. Typically, the coupling devices are secured to the corner castings on the underside of a container prior to the container being moved onto the rail car. The coupling devices are oriented such that the automatic latching lock of each device is outwardly directed and thus ready to be coupled to a previously-loaded container. The automatic latching lock thus allows the container to be stacked and secured to an underlying container simply by landing the upper container onto the lower container. Similarly, the automatic latching lock allows the upper container to be uncoupled from the lower container simply through lifting of the upper container. 
     One common drawback associated with prior art coupling devices having automatic latching locks is repeatability of release loading. More specifically, the vertical force necessary to actuate the automatic latching lock and thus release the upper freight container from the lower freight container must be within an accepted range, and should be repeatable over time and with respect to various containers. As will be appreciated by those skilled in the art, coupling devices themselves are subjected to severe wear through handling and/or exposure to environmental factors. Corner castings of freight containers may also experience wear and/or damage. Together, these factors have made it difficult in the past to provide automatic latching locks, particularly for use in the rail industry, which consistently provide adequate securing forces. 
     Another potential concern when utilizing coupling devices having automatic latching locks on stacked containers concerns toppling loads, i.e., moments which cause the container to tend to topple from its stacked relationship commonly referred to as “rolling moments.” This can be caused by the rolling action of a ship, through the application of wind forces, or by the derailment of a rail car. Under such conditions, the rolling moment experienced by the stacked cargo container could exceed the normal release force of the automatic latching lock of the coupling device thus allowing the stacked container to decouple from the underlying container and/or structure. 
     There is therefore a need in the art for a coupling device including at least one automatic latching lock which allows stacking of and securement of cargo containers without manual intervention. The coupling device preferably exhibits consistent and repeatable release force characteristics. Finally, the coupling device preferably resists rolling moments at onset, while still utilizing a fully automatic latching lock. 
     SUMMARY OF THE INVENTION 
     The present invention, which addresses the needs of the prior art, relates to a coupling device for cooperation with a corner casting of a freight container. The corner casting includes an interior latch-engaging surface. The coupling device includes a body having a base with first and second surfaces. The coupling device further includes an automatic latching lock extending from the first surface of the base and being sized and located for securement to the corner casting of the freight container. The automatic latching lock includes a first support shoulder and a latch assembly. The latch assembly is movably coupled to the support shoulder to allow coupling to and decoupling from the corner casting and is biased to an engagement position. The latch assembly includes a latch having a spring-receiving cavity. Finally, the coupling device includes a spring positioned within the cavity having first and second ends. The first end is supported by the latch, while the second end is surrounded by the cavity and positionally fixed with respect to the base. 
     The present invention further relates to a coupling device for cooperation with a corner casting of a freight container. The coupling device includes a body having a base with first and second surfaces. The coupling device further includes an automatic latching lock extending from the first surface of the base and being sized and located for securement to the corner casting of the freight container. The automatic latching lock includes a first support shoulder and a latch assembly. The latch assembly is movably coupled to the support shoulder to allow coupling to and decoupling from the corner casting and is biased to an engagement position. The latch assembly is movable in a first direction to allow coupling of the automatic latching lock to the corner casting and is movable in a second direction to allow decoupling of the automatic latching lock from the corner casting, the first direction being different from the second direction. 
     The present invention further relates to a coupling device for cooperation with a corner casting of a freight container. The coupling device includes a body having a base with first and second surfaces. The coupling device further includes an automatic latching lock extending from the first surface of the base and being sized and located for securement to the corner casting of the freight container. The automatic latching lock includes a latch assembly. The latch assembly is movably coupled to the base to allow coupling to and decoupling from the corner casting and is biased to an engagement position. The latch assembly includes a latch having a tail. The tail includes an upper contact surface located substantially flush with the first surface of the base when the latch is in the engagement position whereby the corner casting presses against both the first surface of the base and the contact surface of the tail when the automatic latching lock is coupled to the corner casting thus urging the latch to the engagement position. 
     The present invention further relates to a coupling device for coupling a corner casting of a first freight container to a corner casting of a second freight container. The coupling device includes a body having a base. The base has a first surface and a second surface. The coupling device further includes an automatic latching lock for coupling with the corner casting of the first freight container. The automatic latching lock is provided on the first surface of the base. The coupling device further includes a manual twisting lock for coupling with the corner casting of the second freight container. The manual twisting lock is provided on the second surface of the base. The manual twisting lock includes a neck extending from and connected at one end to the second surface of the base. The manual twisting lock further includes a locking element connected to the other end of the neck. The neck includes a pair of opposing protrusions. The manual twisting lock further includes a pair of opposing collar elements each having an interior wall surface. The collar elements surround the neck and are arranged as to allow relative expansion therebetween via interaction between the protrusions and the interior wall surfaces of the collar elements. The interior wall surfaces of the collar elements further include as least one pair of opposing detents sized to receive the protrusions for releasably fixing the collar elements at a predetermined rotational orientation. 
     The present invention further relates to a coupling device for cooperation with a corner casting of a freight container. The corner casting includes an interior latch-engaging surface. The coupling device includes a body having a base with first and second surfaces. The coupling device further includes an automatic latching lock extending from the first surface of the base and being sized and located for securement to the corner casting of the freight container. The automatic latching lock includes a first support shoulder and a latch assembly. The latch assembly is movably coupled to the support shoulder to allow coupling to and decoupling from the corner casting. Finally, the latch assembly includes a wheel rotatable with respect to the first support shoulder. 
     Finally, the present invention relates to a method of stacking a first freight container onto a second freight container. The method includes the step of providing a first rectangular freight container having a length and a width and an upper surface. The first freight container has first, second, third and fourth corner castings located along the upper surface. The first and second corner castings are positioned at one end of the freight container along the width. The third and fourth corner castings are positioned at the other end of the freight container along the width. The method includes the further step of providing a second rectangular freight container having a length and a width and a lower surface. The second freight container has first, second, third and fourth corner castings located along the lower surface. The first and second corner castings are positioned at one end of the freight container along the width. The third and fourth corner castings are positioned at the other end of the freight container along the width. The method includes the further step of providing first, second, third and fourth coupling devices. Each of the coupling devices includes a body having a base with first and second surfaces. Each of the coupling devices further includes an automatic latching lock associated with the first surface. The automatic latching lock includes a landing cone having a positive stop. The landing cone defines a roll-limiting direction. Each of the coupling devices further includes a manual twisting lock associated with the second surface. The method includes the further step of securing the manual twisting locks of the first and second coupling devices to the first and second corner castings of the second container such that each of the landing cones is oriented in a first direction. The method includes the further step of securing the manual twisting locks of the third and fourth coupling devices to the third and fourth corner castings of the second container such that each of the landing cones is oriented in a second direction, the first and second directions being oriented 180° apart from one another. Finally, the method includes the step of landing the second freight container on the first freight container such that the automatic latching locks of the first, second, third and fourth coupling devices engage the first, second, third and fourth corner castings of the first freight container, respectively, whereby the first and second coupling devices limit rolling of the second freight container in a first direction and the third and fourth coupling devices limit rolling of the second freight container in a second direction. 
     As a result, the present invention provides a coupling device including at least one automatic latching lock which allows stacking of and securement of cargo containers without manual intervention. The automatic latching lock of the coupling device exhibits consistent and repeatable release force characteristics over time despite wear to the device and/or corner casting. Finally, the coupling device of the present invention is provided with a positive stop which resists rolling of stacked containers at onset, but nonetheless utilizes a fully automatic latching lock which allows coupling and decoupling of adjacent cargo containers without manual intervention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the coupling device of the present invention; 
     FIG. 2 is a side elevational view of the coupling device of FIG. 1; 
     FIG. 3 is a perspective view of a rail car having freight containers stacked thereon; 
     FIG. 3 a  is an enlarged detail depicting the preferred orientation of the coupling device of FIG. 1 when installed between stacked freight containers; 
     FIG. 3 b  is a perspective view of an alternative coupling device; 
     FIG. 4 is an exploded perspective view of the coupling device of FIG. 1; 
     FIG. 5 is a side elevational view, in partial section, of the coupling device of FIG. 1; 
     FIG. 6 is a plan view, in partial section, of the coupling device of FIG. 1; 
     FIG. 7 is a side elevational view, in partial section, of the coupling device of FIG. 1 during coupling with a corner casting; 
     FIG. 8 is side elevational view, in partial section, of the coupling device of FIG. 1 during decoupling from a corner casting; 
     FIG. 9 is a perspective view showing a first freight container positioned under a second freight container; 
     FIG. 10 is another perspective view of the freight containers of FIG. 9; 
     FIG. 11 is side elevational view depicting the freight containers of FIGS. 9-10 in a stacked arrangement during the application of a rolling moment to the upper freight container; 
     FIG. 12 is a plan view, in partial section, of another alternative coupling device; 
     FIG. 13 is an elevational view of still another alternative coupling device; 
     FIG. 14 is a side elevational view, in partial section, of the coupling device of FIG. 13; 
     FIG. 15 is side elevational view, in partial section, of the coupling device of FIG. 13 during coupling with a corner casting; 
     FIG. 16 is a side elevational view, in partial section, of the coupling device of FIG. 13 during decoupling from a corner casting; and 
     FIG. 17 is a side elevational view of a further alternative coupling device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Coupling device  10  in accordance with the present invention is shown in FIGS. 1-2. Coupling device  10  includes a body  12  having a base  14 . Base  14  includes an upper surface  16  and a lower surface  18 . 
     As will be described more fully hereinbelow, an automatic latching lock  20  is provided on upper surface  16  of base  14 . Automatic latching lock  20  allows coupling to and decoupling from a standard corner casting of a freight container without any manual intervention. Automatic latching lock  20  includes a pair of opposing shoulders  22   a ,  22   b  and a latch assembly  24 . As shown, shoulders  22   a ,  22   b  are substantial mirror images of one another about a plane extending along axis X and arranged perpendicular to surface  16  of base  14 . Shoulders  22   a ,  22   b  together form a landing cone which serves to locate and thereafter guide automatic latching lock  20  into engagement with a corner casting of an adjacent freight container. 
     Located on the opposite side of base  14  is a manual twisting lock  26  which includes a locking element  28  and a rotatable engagement collar  30 . As will be recognized by those skilled in the art, manual twisting lock  26  is secured to a corner casting in a conventional manner, i.e., a cargo handler inserts twisting lock  26  into a corner casting and thereafter manually twists the coupling device to secure locking element  28  within the corner casting. The orientation of locking element  28  in its locked position is shown in FIG. 3 a.    
     Referring now to FIG. 3, coupling device  10  may be utilized to lock an upper freight container  32  to a lower freight container  34 . In the arrangement shown in FIG. 3, lower freight container  34  is already secured to the surface of a rail car  36 . Alternatively, coupling device  10  may be utilized to secure a freight container directly to the surface of a rail car. In this case, coupling device  10  is secured to the surface of the rail car such that automatic latching lock  20  is upwardly directed. When securing cargo containers directly to the surface of a rail car, coupling device  10  is preferably modified to remove manual twisting lock  26  and thus allow attachment of base  14  directly to the surface of the rail car (see coupling device  312  shown in FIG. 3 b ). Of course, it is contemplated that coupling device  10  can be used in other applications, e.g., securement of stacked container on cargo ships. 
     As will be appreciated by those skilled in the art, one preferred technique of stacking freight containers involves the attachment of the coupling devices to the underside of upper freight container  32  prior to the landing of upper freight container  32  onto lower freight container  34 . Specifically, a cargo handler manually installs four coupling devices on the underside of upper freight container  32  by inserting manual twisting lock  26  into the corner casting located on the underside of upper freight container  32 , and thereafter manually twisting the coupling device to secure the coupling device to the corner casting. This process is repeated at each corner of upper freight container  32 . The coupling devices are thus secured to the underside of upper freight container  32  in the orientation shown in FIG. 3 a . Upper freight container  32  is then moved by a crane (not shown) into a position above freight container  34  and then landed thereon. As will be described more fully hereinbelow, automatic latching lock  20  allows both coupling and decoupling of the cargo containers without the need for any manual intervention. 
     Referring now to FIG. 4, the components of coupling device  10  are shown in an exploded format. As illustrated, body  12  is preferably formed as a one-piece component by a suitable process such as casting. Each of shoulders  22   a ,  22   b  include an aperture  38   a ,  38   b  for receipt of a pivot pin  40 . As shown, latch assembly  24  includes a latch  42  having a cavity  44  for receipt of a compression spring  46 . Thus, the lower end of the spring is supported by the latch. A bolt  48  extends through an aperture  50  (see FIG. 5) and engages a threaded aperture  52  (see FIG. 5) formed in base  14 , thus maintaining spring  46  within cavity  44 . A washer  54  is located at the upper end of the spring and cooperates with the head of bolt  48 , thus positionally fixing the upper end of the spring with respect to base  14  (see FIG.  5 ). 
     It will be appreciated that bolt  48  allows for tensioning adjustment of spring  46 . The force required to move latch  42  and thus release the coupling device from the corner casting may therefore be adjusted. More particularly, by turning bolt  48 , the release tension of latch  42  may be adjusted. 
     Latch  42  includes a triangular aperture  56  extending therethrough and is shown in its “engagement” position in FIG.  5 . In the “engagement” position, curved surface A of triangular aperture  56  is pressed against pin  40 . Surface A is best seen in FIG.  4 . Triangular aperture  56  also includes curved surfaces B and C. Latch  42  also includes a lip  57  which is configured to engage an interior surface of a corner casting when automatic latching lock is coupled thereto. As shown in FIG. 5, lip  57  preferably forms an acute angle α with respect to a surface perpendicular to upper surface  16  when latch  42  is in its engagement position. At the minimum, lip  57  is oriented parallel to upper surface  16  when latch  42  is in its engagement position. 
     As shown in FIGS. 4-6, rotatable engagement collar  30  includes a pair of opposing collar elements  58  which are secured together via bolts  60  and nuts  62 . A spring  64  is inserted within an aperture  66  formed in neck  68  of body  12 . A pair of detent balls  70  are also installed within aperture  66 , and press against the inside surfaces  72  of collar elements  58 . Inside surfaces  72  of collar elements  58  are formed with detents  74  which receive balls  70  and thus rotationally fix collar elements  58 , as shown in FIG.  6 . 
     Referring back to FIGS. 1-2, shoulder  22   a  includes a pair of opposing guide surfaces  76   a ,  78   a , while shoulder  22   b  includes a pair of opposing guide surfaces  76   b ,  78   b . Each of shoulders  22   a ,  22   b  further includes a chamfered surface  80   a ,  80   b , respectively, to help position and guide automatic latching lock  20  into a corner casting of a freight container. Shoulder  22   a  also includes corner casting engagement surfaces  82   a ,  84   a , while shoulder  22   b  includes corner casting engagement surfaces  82   b ,  84   b . Surfaces  82   a ,  84   a  are substantially parallel to one another and perpendicular to upper surface  16  of base  14 . Similarly, engagement surfaces  82   b ,  84   b  are substantially parallel to one another and perpendicular to upper surface  16  of base  14 . Surfaces  82   a ,  82   b  define a plane P 1 , while surface  84   a ,  84   b  define a plane P 2 . 
     Referring now to FIG. 7, the manual twisting lock  26  of coupling device  10  is shown secured to corner casting  86 . In this regard, rotatable engagement collar  30  is captured between opposing walls  88  of corner casting  86 , thus preventing rotation of body  12  with respect thereto. As shown, locking element  28  prevents withdrawal of coupling device  10  from corner casting  86 . 
     FIG. 7 further illustrates the displacement of latch  42  during coupling of device  10  with corner casting  90 . More particularly, as corner castings  86  and  90  are moved toward each other, guide surfaces  76   a ,  76   b  contact edge  92  of corner casting  90 . As the two corner castings are moved toward each other and as guide surfaces  76   a ,  76   b  slide along edge  92 , latch  42  is caused to move to the orientation shown in FIG. 7 (i.e., curved surface B of triangular aperture is pressed against pin  40 ), which allows the shoulders/latch arrangement to be fully inserted within corner casting  90 . 
     As illustrated, spring  46  undergoes substantially straight compression. This is accomplished through the novel arrangement of spring  46  within cavity  44 , and the securement of spring  46  to base  14  via bolt  48  and washer  54 . Particularly, cavity  44  is sized to allow the latch to move with respect to the bolt-spring arrangement (e.g., the pivoting of latch  42  depicted in FIG.  7 ), while maintaining the desired straight compression of spring  46 . It will be appreciated that the ability to limit spring  46  to substantially straight compression will provide more accurate predictability regarding the force required to compress the spring, and will provide improved repeatability of release loading. Although spring  46  is depicted as a coil spring, the use of solid (i.e., elastomeric) springs is contemplated herein. The incorporation of cavity  46  within latch  42  allows the use of such solid springs. 
     The displacement of latch  42  during decoupling of corner casting  90  from corner casting  86  is shown in FIG.  8 . In this regard, latch  42  is displaced until curved surface C of triangular aperture  52  is pressed against pin  40 . Again, spring  46  undergoes substantially straight compression, thus ensuring the predictability and repeatability of the force required to decouple automatic latching lock  20  from corner casting  90 . The movement of latch  42  during decoupling of device  10  from corner casting  90  requires additional compression of spring  46 . It will be appreciated that this design allows the force required to decouple the device from the corner casting to be greater than the force required to couple the device to the corner casting. 
     One disadvantage associated with prior art automatic latching locks that will be recognized by those skilled in the art is an inability to positively verify that the latch has returned to its engagement position following landing of a container, thus locking the automatic latching lock to the corner casting of the container. The novel design of the present invention ensures that the latch is returned to its engagement position following landing of a container. 
     More particularly, latch  42  includes a tail  43  as shown in FIGS. 4-5 and  7 - 8 . When latch  42  is in its engagement position (as shown in FIG.  5 ), surface  43   a  of tail  43  is located substantially flush with upper surface  16  of base  14 . As discussed hereinabove, latch  42  will pivot during coupling of such latch to corner casting  90  (see FIG.  7 ). It will be appreciated that once corner casting  90  is coupled to device  10 , the weight of the container will press against surface  16  thus returning base  14  to a horizontal orientation, and will also press against surface  43   a  of tail  43  thus forcing latch  42  into its engagement position. Of course, it is contemplated herein that the present latch/tail arrangement could be utilized in other automatic latching lock arrangements. 
     In one alternative embodiment, the location of triangular aperture  56  and apertures  38   a ,  38   b  are reversed, that is, each of apertures  38   a ,  38   b  is replaced with a triangular aperture similar to aperture  56 , while triangular aperture  56  is replaced with a circular aperture similar to apertures  38   a ,  38   b  and sized to receive pivot pin  40 . Thus, in this embodiment, pin  40  moves with latch  42  as the latch is displaced during coupling and decoupling. The triangular aperture located in the shoulders in this embodiment allow such movement. In another alternative embodiment, the configuration of aperture  56  of latch  42  is modified, e.g., the triangular aperture may be replaced with an L-shaped aperture having a pathway extending between curved surfaces A and B, and continuing between curved surfaces B and C, or may be replaced with any other suitable configuration. 
     The novel configuration of coupling device  10  allows such device to be arranged in a manner which limits the ability of a container to “lift-off” the underlying structure or container due to a rolling movement. More particularly, coupling device  10  is provided with a positive stop which prevents rolling at onset. The positive stop is defined as the region located on each of the shoulders which intersects and extends beyond plane P 2  in a direction extending away from plane P 1 , e.g., region  93   b  of shoulder  22   b  shown in FIG. 2 (the positive stop includes a similar region located on shoulder  22   a ). 
     Referring to FIGS. 9-10, four coupling devices in accordance with the present invention are located and oriented as shown at the four corners of freight container  32 . Thus, coupling devices  10   a  and  10   b  are located at the proximate end of cargo container  32  and are oriented in the same direction, while coupling devices  10   c  and  10   d  are located at the distal end and oriented in the same direction as each other, but are rotated 180° with respect to the orientation of coupling devices  10   a  and  10   b.    
     Referring now to FIG. 11, a force F applied to upper cargo container  32  will create a rolling movement which tends to lift the right-hand side of freight container  32  (as viewed in FIG. 11) with respect to the right hand side of lower freight container  34 . Although this movement of upper freight container  32  may actuate release latch  42 , interior latch-engaging surface  94  of corner casting  90   b  will contact surfaces  78   a ,  78   b  (which form a portion of the mentioned positive stop) of shoulders  22   a ,  22   b  at the onset of rolling, thus limiting any vertical movement of coupling device  10   b  with respect to corner casting  90   b . Thus, the orientation of coupling devices  10   a  and  10   b  prevents rolling of the cargo container  32  in a counter clockwise direction. Inasmuch as coupling devices  10   c  and  10   d  are oriented 180° from the orientation of coupling devices  10   a  and  10   b , coupling devices  10   c  and  10   d  will prevent rolling of the container in a clockwise direction. 
     The arrangement of the devices shown in FIGS. 9-10 thus causes a degree of relative rotation between the adjacent containers during loading and unloading. During loading, the upper cargo container must be rotated slightly to allow all four automatic latching locks to initially engage the openings in the corner castings of the lower cargo container. The coupling of the automatic latching locks to the corner castings causes a translation of coupling devices  10   a  and  10   b  to the right (as oriented in FIG. 10) and a translation of coupling devices  10   c  and  10   d  to the left (as oriented in FIG.  10 ). Together, this translation causes counter clockwise rotation of upper cargo container  32  during loading (as viewed looking down at upper cargo container  32 ). This translation and rotation is repeated in reverse during unloading of the upper cargo container. 
     In one alternative embodiment of the present invention (as shown in FIG.  12 ), neck  68 ′ of coupling device  10 ′ includes a pair of opposed protrusions  96 . A spring washer  98  is located at the head of each bolt  60  and at the bolt/nut interface. Collar elements  58 ′ include detents  100 . As engagement collar  30 ′ is rotated about neck  68 ′, protrusions  96  force collar elements  58 ′ apart by compressing spring washers  98 . Once engagement collar  30 ′ is rotated 90°, protrusions  96  are positioned within detents  100  thus allowing collar elements  58 ′ to pull together due to the force of spring washers  98 . Accordingly,. engagement collar  30 ′ becomes rotatably locked in this orientation. To rotate engagement collar  30 ′ again, a twisting force must be applied thereto sufficient to overcome the force of the spring washers and move protrusions  96  out of detents  100 . 
     An alternative embodiment, i.e., coupling device  110 , is shown in FIGS. 13-16. Coupling device  110  includes a body  112  having a base  114 . Base  114  includes an upper surface  116  and a lower surface  118 . Automatic latching lock  120  includes a pair of opposing support shoulders  122   a ,  122   b  and a latch assembly  124 . Shoulders  122   a ,  122   b  are substantial mirror images of one another. Shoulders  122   a ,  122   b  together form a landing cone which serves to locate and thereafter guide the automatic latching lock into engagement with a corner casting of an adjacent freight container. Coupling device  110  further includes a manual twisting lock  126 , which in turn includes locking element  128  and a rotatable engagement collar  130 . Manual twisting lock  126  functions in the same manner as described hereinabove with respect to manual twisting lock  26 . 
     Body  112  is preferably formed as a one piece component by a suitable process such as casting. Each of shoulders  122   a ,  122   b  include an aperture  138   a ,  138   b  for receipt of a pivot pin  140 . Latch assembly  124  is similar to latch assembly  24 , and includes a latch  142  having a cavity  144  for receipt of a compression spring  146 . A bolt  148  extends through an aperture  150  and engages a threaded aperture  152  formed in base  114 , thus maintaining spring  146  within cavity  144 . A washer  154  is located at the upper portion of the spring and cooperates with the head of bolt  148  to allow tensioning adjustment of spring  146 .; Finally, latch  142  includes a triangular aperture  156  extending therethrough. 
     Latch  142  is shown in its “engagement” position in FIG.  14 . In the “engagement” position, curved surface A of triangular aperture  156  is pressed against pin  140 . Triangular aperture  156  also includes curved surfaces B and C. 
     Referring now to FIG. 15, coupling device  110  is shown being coupled to corner casting  90  of a cargo container (not shown). As support shoulders  122   a ,  122   b  penetrate rectangular opening  189  of corner casting  90 , latch  142  is translated to the position shown in FIG.  15 . More particularly, latch  142  is translated until curved surface B of triangular aperture  156  is pressed against pin  140 . This movement of latch  142  causes compression of spring  146 . Again, the design of cavity  144  allows relative movement between the latch and the bolt/spring arrangement, thus ensuring that the compression of spring  146  is substantially straight. 
     Referring now to FIG. 16, coupling device  110  is shown being removed from corner casting  90 . During this removal, latch  142  is translated to the position shown in FIG.  16 . More particularly, latch  142  is translated until curved surface C of triangular aperture  156  is pressed against pin  140 . The movement of latch  142  during removal of coupling device  110  from corner casting  90  requires additional compression of spring  146 . It will be appreciated that this design allows the force required to decouple the device from the corner casting to be greater than the force required to couple the device to the corner casting. Moreover, the design of the automatic latching lock, which ensures that spring  146  undergoes substantially straight compression, provides the coupling device with repeatability of its release force characteristics. 
     In another embodiment of the present invention, as shown in FIG. 17, the latch of coupling device  212  is replaced by a wheel  242 . Wheel  242  facilitates coupling and decoupling of the latching lock due to the rotation of the wheel when contacting the corner casting. 
     It will be appreciated that the present invention has been described herein with reference to certain preferred or exemplary embodiments. The preferred or exemplary embodiments described herein may be modified, changed, added to or deviated from without departing from the intent, spirit and scope of the present invention, and it is intended that all such additions, modifications, amendment and/or deviations be included within the scope of the following claims.