Abstract:
A coupling piece for joining two containers ( 35, 36 ) that are stacked one atop the other, particularly onboard ships is provided. Such a coupling is provided at corner fittings ( 43, 44 ) and each include a stop plate ( 21 ) and a coupling projection ( 22, 23 ) on each side of the stop plate ( 21 ). A first coupling projection ( 22 ) can be placed on the corner fitting of one container ( 36 ) and the other coupling projection ( 23 ) is provided with a locking catch ( 28, 46, 54 ) for locking inside a corner fitting of the other container ( 35 ). The drawback that front-side openings in upper corner fittings ( 43, 44 ) of a container ( 36 ) are obstructed by a locking catch of the coupling piece, hindering the use of lashing means is overcome with the coupling piece locking catch ( 28, 46, 54 ), when viewed in the longitudinal direction of the containers ( 35, 36 ), being arranged laterally on the other coupling projection ( 23 ).

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a United States National Phase application of International Application PCT/EP2003/004162 and claims the benefit of priority under 35 U.S.C. § 119 of German Application DE 102 38 895.4 filed Aug. 24, 2002, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention pertains to a coupling piece for joining two containers that are stacked one atop the other, particularly onboard ships, at their corner fittings, comprising a stop plate and a coupling projection on each side of the stop plate, of which the first coupling projection can be placed on the corner fitting of one container and the other coupling projection is provided with a locking catch for locking inside a corner fitting of the other container. Furthermore, the present invention pertains to an arrangement of containers that are stacked one atop the other, and to a method for joining containers that are stacked one atop the other with coupling pieces of this type.  
       BACKGROUND OF THE INVENTION  
       [0003]     Such a coupling piece is known, e.g., from DE 298 11 460 U1. This coupling piece is a so-called midlock, which is used for lashing containers as deck cargo onboard ships, especially for joining two containers stacked one atop the other. The midlock is used whenever two 20-foot containers are placed on a space for a 40-foot container, namely at the container corner fittings on the front sides, facing one another, of the 20-foot containers, standing one behind the other. In fact, only a very narrow gap of about 76 mm is produced between the 20-foot containers standing one behind the other, such that the corner fittings arranged on these sides and therefore the midlock as well are poorly accessible for stevedores. The corner fittings are freely accessible on the other, free front sides. So-called twistlocks are generally used here, which are opened manually by the stevedore when unloading the container. The container is then raised, whereby the midlocks slide out of the corner fittings of the lower container because of the inclined standing of the container.  
         [0004]     During the loading of the container, the midlocks are first suspended in the lower corner fitting of the upper container with the containers hovering over land. To this end, in older variants, hook-type catches were used on a front side (the side pointing in the longitudinal direction of the container to the front side of same) of the upper coupling projection. More contemporary variants, such as, for example, the midlock also illustrated in DE 298 11 460 U1, have lateral projections on the upper coupling projection that extend approximately in parallel to the stop plate. These projections grip into the lower corner fitting of the upper container. The opposite, lower coupling projection has a locking catch on a front side. When the upper container is placed on the lower container which is already located onboard the ship, either the entire midlock then slides against the upper container or the entire upper container slides forwards or backwards on a lower inclined surface of the locking catch and catches in the upper corner fitting of the lower container during the further lowering of the container.  
         [0005]     This midlock has the following drawback. Usually onboard ships, the rear container corner fitting, into which a midlock is usually inserted, is poorly accessible, as explained above. However, there are also container ships, in which the containers are still accessible at least at some of the loading spaces, or because not all loading spaces are occupied, for attaching additional lashing means, for example, lock rods. However, in the prior-art midlocks, lashing means cannot be fastened in the upper corner fitting of the lower container, since the front-side opening is occupied because of the locking catch engaging therein. For this reason, a special hook fitting of a lock rod is suggested in DE 100 04 359 A1, which grips around the locking catch of conventional midlocks. Up to now, this hook fitting has not been used in practice.  
       SUMMARY OF THE INVENTION  
       [0006]     Based on the above, the basic object of the present invention is to create a coupling piece as well as an arrangement of containers stacked one atop the other and a method for joining containers stacked one atop the other, in which the front-side opening of the upper corner fitting of a container remains free for lashing means.  
         [0007]     To accomplish this object, the coupling piece according to the present invention is characterized in that the locking catch, viewed in the longitudinal direction of the container, is arranged laterally on the other coupling projection. The arrangement according to the present invention is characterized in that the containers are joined with one another at least at the corner fittings of a front side of the container with the coupling piece according to the present invention each. According to the method according to the present invention, the upper container is swung horizontally about its vertical axis, or, as an alternative, is offset laterally when coupling and/or uncoupling with the lower container.  
         [0008]     Because of the lateral arrangement of the locking catch, the front-side bore hole of the corner fitting of the lower container remains freely accessible for lashing means. The locking catch is assigned to a lateral opening of the corner fitting which is not usually used for lashing containers onboard ships anyway, where it therefore also does not lead to interference.  
         [0009]     However, the measure according to the present invention offers another advantage. As is explained above, 20-foot containers are joined with one another on loading spaces for 40-foot containers by means of two different fittings by stacking one atop the other, and especially with two midlocks, on the one hand, and with two twistlocks, on the other hand. Thus, different fittings must be provided onboard the ship. Moreover, a twistlock that is inadvertently used instead of a midlock can often be removed only with difficulty. Therefore, efforts have been made in the past to create a universally insertable fitting, a so-called universal lock (also called unilock), which can be universally inserted at all positions. An example of the universal lock of this type is the subject of DE 101 05 785 A1. The universal locks proposed until now have not yet found a good footing in practice. Furthermore, they have the drawback that, when unloading the container, the stevedore must always still manually open the universal lock at the accessible container corner fittings (“twistlock position”), so that it is unlocked with the upper corner fitting of the lower container.  
         [0010]     In order to prevent this and to create a coupling piece that can be unlocked without the involvement of stevedores, so-called fully automatic devices were proposed in DE 43 07 781 A1 and in WO 01/76980 A1, in which movable locking elements are provided. These locking elements move as a result of movements of the ship, particularly rolling movements, during travel and thereby lock the coupling piece with the upper corner fitting of the lower container. In WO 01/76980 A1, a ball movable in a cage is provided as the locking element. In DE 43 07 781 A1, it is suggested to use a pivotable block, which pivots from one side to the other depending on the position of the ship, and thus interlocks under the elongated hole of the upper corner fitting of the lower container. In this case, the locking elements are provided such that, when the ship is at rest, i.e., in the harbor, they automatically reach a rest position, in which they unlock the coupling piece with the upper corner fitting of the lower container, so that the upper container can be unloaded.  
         [0011]     However, the drawback of these fully automatic devices is that the movable locking elements are very susceptible, in particular, to dirt. Therefore, these fully automatic devices are very trouble-prone even with good maintenance.  
         [0012]     A coupling piece equipped with the features according to the present invention can also be used as a fully automatic device. A coupling piece each is inserted into all four lower corner fittings of the upper container. Using four coupling pieces of the same design automatically results in the locking catches pointing in different directions on the “front” corner fittings, on the one hand, and the “rear” corner fittings, on the other hand. When placing the thus prepared container on the lower container, the container rotates easily about its vertical axis, in particular because of the shape of the coupling pieces, and the lower coupling projections of the coupling pieces lock with the locking catches into the corner fittings of the lower container. This results in a secure locking of the containers stacked one atop the other during movements of the ship. Because of rolling movements of the ship in its travel, the containers tilt in the transverse direction. As a result, one long side of the container is under pressure load, while the opposite long side is under tension load. The coupling pieces on the pressure side of the container prevent the shifting of the entire container, such that the locking catch on the tension side cannot disengage from the upper corner fitting of the lower container and thus reliably transfers the tensile forces between the upper and lower containers on the tension side. Containers stacked in the bow section of a ship, in which the case may arise that tensile loads occur on all four coupling pieces because of nosing of the ship under circumstances, are also held securely. Because of the mass moment of inertia of the respective upper container, this will not by itself rotate against the respective lower container, so that a secure locking is also given under these circumstances.  
         [0013]     According to a design embodiment of the present invention, the length of the other (lower) coupling projection is slightly shorter than the length of an associated elongated hole of the associated corner fitting of the other (lower) container. Correspondingly, the maximum width of the locking catch should also be slightly less than the width of the elongated hole. The lower coupling projection thus just passes through the elongated hole, which is completely sufficient for the desired coupling and uncoupling of the containers stacked one atop the other; it opposes an undesired uncoupling because of movements of the ship, however. This is further supported if leading edges of the other (lower) coupling projection have a contour that corresponds to the contour of the assigned elongated hole in this area. Consequently, the coupling piece has only a very small play in the longitudinal direction, so that the coupling piece is also blocked in the transverse direction. There is thus further improved securing against shifting of the coupling piece in the transverse direction, so that the secure joining of the containers stacked one atop the other is further improved by means of the locking catch.  
         [0014]     According to another design embodiment of the present invention, a lead-in taper is arranged under the locking catch for the facilitated introduction of the lower coupling projection into the associated elongated hole at the container corner fitting. This lead-in taper tapers downwards, so that it brings about coupling for the correct positioning of the lower coupling projection, and thus of the entire coupling piece.  
         [0015]     At the junction between the stop plate and the lower coupling projection, a lead-in chamfer should be arranged on the long side of the lower coupling projection facing away from the locking catch. After the coupling piece has been correctly positioned by the lead-in taper for insertion into the elongated hole, the lead-in chamfer is now used by the further lowering of the upper container. By means of the lead-in chamfer, the coupling piece is pushed, especially by means of further lowering of the upper container, in the direction in which the locking catch points and consequently brings about the coupling of the upper container with the lower container (locking position). Furthermore, the coupling piece has only a little play in the transverse direction of the container because of the lead-in chamfer, so that the locking catch always reliably undercuts the elongated hole of the upper corner fitting of the lower container. Thus, a further improvement is provided in the secure binding of the containers stacked one atop the other.  
         [0016]     The lead-in chamfer has an angle corresponding [typo in original—Tr. Ed.] to a chamfer at the upper elongated hole of the upper container corner fitting and thus fits tightly in the elongated hole. As an alternative, only the upper area pointing to the stop plate corresponding to the length of the chamfer at the elongated hole may be provided with an angle corresponding to the chamfer at the elongated hole. A flatter curve as compared with this chamfer is then provided under this chamfer. Consequently, the vertical distance between the locking catch and the stop plate can be reduced, as a result of which the vertical play of the coupling piece in the corner fitting is also simultaneously reduced. Consequently, the certainty of lashing the containers joined with one another onboard the ship is further increased.  
         [0017]     To make the uncoupling easier, a sloping shoulder may be arranged on the top side of the locking catch. This variant, in particular, especially suitable for fully automatic devices. However, as an alternative, the top side may also have a horizontal top side. In order to make the uncoupling easier then, the locking catch should be provided with a side wall directed sloping inwardly. This variant is particularly suitable for midlocks and may be used in addition or as an alternative to the sloping shoulder on the top side of the locking catch.  
         [0018]     According to an alternative exemplary embodiment of the coupling piece according to the present invention, the locking catch is designed such that it is cross-slidable in relation to the lower coupling projection. When the lower coupling projection is inserted into the upper elongated hole of the upper corner fitting of the container, the locking catch is pushed back against the lower coupling projection and then, after insertion in the elongated hole, is pushed back again into the locking position by means of the force of a spring. This variant is advantageous with containers very close to one another onboard, since the containers now no longer have to be rotated about their vertical axis during loading because of the “alternative” locking catch.  
         [0019]     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The present invention is explained in detail below based on exemplary embodiments shown in the drawings, in which:  
         [0021]      FIG. 1  is a partially cutaway, side view of a coupling piece having the features of the present invention;  
         [0022]      FIG. 2  is a front view of the coupling piece according to  FIG. 1 ;  
         [0023]      FIG. 3  is a schematic view of two containers during the loading of same, shortly before locking;  
         [0024]      FIG. 4  is a schematic view of the containers during unloading shortly after unlocking;  
         [0025]      FIG. 5  is a detail of the containers during the loading and unloading of the containers;  
         [0026]      FIG. 6  is a detail of the containers stacked one atop the other in the locked state;  
         [0027]      FIG. 7  is a schematic top view of two containers during locking and unlocking;  
         [0028]      FIG. 8  is a schematic top view of the lower container in the locked state;  
         [0029]      FIG. 9  is a partially cutaway, side view of a second exemplary embodiment of a coupling piece having the features of the present invention;  
         [0030]      FIG. 10  is a front view of the coupling piece according to  FIG. 9 ;  
         [0031]      FIG. 11  is two containers stacked one atop the other with a coupling piece according to  FIG. 9  when unloading shortly before unlocking;  
         [0032]      FIG. 12  is a side view of a detail of the containers according to  FIG. 11  shortly before unlocking;  
         [0033]      FIG. 13  is a front view of the detail of the container according to  FIG. 12 ;  
         [0034]      FIG. 14  is a top view of the detail of the container according to  FIG. 12 ;  
         [0035]      FIG. 15  is, a front view of a third exemplary embodiment of a coupling piece having the features of the present invention;  
         [0036]      FIG. 16  is a front view of another exemplary embodiment of a coupling piece having the features of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]     Referring to the drawings in particular, the embodiments of a coupling piece according to the present invention shown in  FIGS. 1 through 8  are particularly suitable as so-called fully automatic devices  20 , also designated as unilocks. The fully automatic device  20  comprises a central stop plate  21  and coupling projections  22  and  23  extending upwards and downwards therefrom. On the upper coupling projection  22  are arranged lateral projections  24 ,  25 , which grip behind a lower elongated hole of a container corner fitting, so that they are interlocked within this corner fitting. A locking piece  26 , which can be pivoted to the side into the plane of the stop plate  21  by means of a hand lever  27 , is used to lock and unlock the upper coupling projection  22  in this container corner fitting. To this extent, the present fully automatic device  20  still corresponds to a conventional midlock, as is shown, for example, in DE 298 11 460 U1, and, like this midlock, is inserted into the lower corner fitting of the upper container by the stevedore.  
         [0038]     Since the upper elongated holes on the upper corner fittings are always directed in the longitudinal direction of the container just as the lower elongated holes of the lower corner fittings in standard containers, the hand levers  27  are always turned toward the container front side (the front provided with doors or the closed back). Therefore, within the framework of this specification and the claims the side of the hand lever  27  is designated as the front V, the opposite side is designated as the back R and the sides adjacent hereto, pointing from the front V to the back R, are designated as the long sides L.  
         [0039]     The lower coupling projection  23  is designed in a special manner. This coupling projection  23  has a projecting locking catch  28 . As can be seen in  FIGS. 1 and 2 , the locking catch  28  is assigned to one of the two long sides L, especially the right-hand long side L according to the view in  FIG. 2 . The locking catch  28  is arranged laterally, so that an opening of the container corner fitting assigned to the front sides of the container remains free for hooking in lashing means.  
         [0040]     Under the said locking catch  28 , the coupling projection  23  is provided with a downwardly directed lead-in taper  29 . At the junction from the lower coupling projection  23  to the stop plate  21 , a lead-in chamfer  30  is provided on the long side L of the lower coupling projection  23  facing away from the locking catch  28 . The lead-in chamfer  30  causes the respective fully automatic device  20  to shift to the right in the view according to  FIG. 2  when the fully automatic device  20  is inserted into the upper corner fitting of the lower container, i.e., when the upper container is placed on the lower container.  
         [0041]     On the side of the lower coupling projection  23  opposite the lead-in chamfer  30 , a chamfer  31  is provided at the junction between the coupling projection  23  and the stop plate  21 . This chamfer is primarily provided for reasons of stability. However, as can be seen in  FIG. 2 , the chamfer  31 , as well as the upper part of the lead-in chamfer  30 , correspond exactly to a chamfer  32  at the elongated hole  33  of the corner fitting.  
         [0042]     The length  1  of the lower coupling projection  23  is only slightly less than the length of the elongated hole  33 . The width b of the locking catch  28  at its widest point is likewise only slightly less than the width of the elongated hole  33 . The projecting depth t of the locking catch  28  is thus only slightly less than the distance a of the side surface of the coupling projection  28  facing away from the locking catch  28  from the associated inside wall of the elongated hole  33  ( FIG. 2 ).  
         [0043]     To make unlocking easier, the locking catch  28  is provided with an outwardly sloping shoulder  34 . When the upper container and thus the fully automatic device  20  are raised, the shoulder  34  abuts against the bottom of the container corner fitting, so that the fully automatic device  20  is pressed to the left in the view according to  FIG. 2  and is thus disengaged from the elongated hole  33 .  
         [0044]      FIGS. 3 through 8  show the loading and unloading of containers using the fully automatic device  20 .  FIG. 3  shows a container  35  already parked, e.g., onboard ships, onto which another container  36  shall be placed. The other container  36  is shown in the position shortly before the locking on the lower container  35 . As can be recognized in  FIG. 5 , the fully automatic device  20  sets down on the, upper edge of the elongateed hole  33  with the lead-in taper  29  and it is then locked by means of a movement of the entire upper container  36  by means of a longitudinal rotation of the container  36  about its vertical axis (see  FIG. 7 , arrow  37 ). The sequence of movements of the fully automatic device is illustrated by the combination of arrows  38  in  FIGS. 4 and 5 . The front fully automatic devices  20  first slide to the left (arrow  38 . 1 ) during the locking because of the lead-in taper  29 , while the rear fully automatic devices  20  slide to the right. By means of further lowering of the upper container  36 , the fully automatic device  20  falls vertically at first (arrow  38 . 2 ). By means of even further lowering of the upper container  36 , the front fully automatic devices  20  finally slide to the right (arrow  38 . 3 ), while the rear fully automatic devices  20  analogously slide to the left into their respective locking position.  FIG. 6  shows the containers  35 ,  36  finally in the completely locked position.  
         [0045]     Analogously to  FIG. 3 ,  FIG. 4  shows the upper container  36  shortly after unlocking during the unloading of the container  36 . The container [ 36 ] is in turn rotated slightly about its vertical axis in relation to the lower container  35 . The front fully automatic devices  20  slide upwards to the left corresponding to arrow  40  in the view according to  FIG. 4  and  FIG. 5  out of the elongated holes  33 , while the rear fully automatic devices  20  slide out of the elongated holes  33  upwards to the right according to arrow  41  in  FIG. 4 . The container  36  thus rotates clockwise according to arrow  42  in  FIG. 7  during unloading. These directions according to the arrows  38 ,  40 ,  41 ,  42  arise, since the fully automatic devices  20  assigned to the front corner fittings  44  of the containers  35 ,  36 , on the one hand, and the locking catches  28  of the fully automatic devices  20  assigned to the rear corner fittings  43 , on the other hand, point in opposite directions with their locking catches  28 .  
         [0046]     It can be easily seen in  FIG. 8  that front and rear leading edges  39  of the fully automatic device, more exactly of the lower coupling projection  23 , have a contour at least in the area of the elongated hole  33  of the upper corner fitting  43 ,  44  of the lower container  35  that corresponds to the contour of the elongated hole  33 . Concretely, an arc-shaped contour is provided.  
         [0047]     If the fully automatic devices  20  assigned to the rear corner fittings  43  or the ones assigned to the front corner fittings  44  are inadvertently inserted the wrong way around, this is also not the end of the world. The container  36  is then lowered and raised entirely offset laterally during the locking and unlocking. However, such a situation should be avoided by the careful work of the stevedore. If only one of the fully automatic devices is inserted the wrong way around, such that the locking catches  28  assigned to the front corner fittings  44  and to the rear corner fittings  43  point towards one another or point away from one another, the container cannot be locked at all. The stevedore notices this, so that the container can be raised again and the mistake can then be corrected. At any rate, a situation, in which the fully automatic device locks and then unlocks only with great difficulty and thus the container cannot be unloaded, cannot occur.  
         [0048]     A coupling piece that is particularly suitable as a midlock  45  is shown in  FIGS. 9 through 14 . The midlock  45 , in its essential components, corresponds to the fully automatic device  20  according to  FIGS. 1 through 8 , so that comparable components in  FIGS. 9 through 14  are designated with the same reference numbers as in  FIGS. 1 through 8 . However, as can be seen in  FIG. 10 , a locking catch  46  of the midlock  45 , which is likewise arranged laterally, does not have a sloping shoulder, but rather has a somewhat horizontal top side  47 . An outer side wall  48  of the locking catch  46  is guided sloping inwardly on the side facing away from the hand lever  27 , as this can be particularly easily seen in  FIG. 14 .  
         [0049]     The unlocking of the upper container  36  from the lower container  35  is shown in  FIGS. 11 through 14 . First, on the front corner fittings  44  that are freely accessible to the stevedore, a semiautomatic twistlock  49  inserted there is manually unlocked by the stevedore. Then, the container  36  is raised with a container loading crane (arrow  50 ). The front corner fittings  44  of the containers  35 ,  36  lift off from one another and the container  36  tilts. Consequently, the midlock  45  also tilts, as can be easily seen particularly in  FIG. 12 . Because of the sloping side wall  48 , the midlock  45  is now pressed to the left in the view according to  FIG. 13  (arrow  51 ), as a result of which the locking catch  46  is released from the elongated hole  33 .  
         [0050]     The locking of the container  36  and of the midlock  45  during the loading of the container  36 , i.e., when same is placed on the lower container  35 , is performed analogously to the fully automatic device  20  explained based on  FIGS. 1 through 8 .  
         [0051]      FIG. 15  shows an exemplary embodiment, in which the lead-in chamfer is first provided with a steeper chamfer  52 . The angle of this chamfer ( 52 ) corresponds to the angle of the chamfer  32  at the elongated hole  33  of the container corner fitting. Under this chamfer  52 , the lead-in chamfer  30  passes over into a chamfer  53  with an angle that is flatter compared to the chamfer  52 . This variant has the advantage that the vertical distance between the bottom of the stop plate  21  and the upper shoulder  34  on the locking catch  28  can be shortened. This also results in a smaller vertical play of the coupling piece. The containers thus joined with one another for safety are thus improved.  
         [0052]     In the exemplary embodiment shown in  FIG. 16  the locking catch  54  is displaceable against the lower coupling projection  23 . Concretely, the locking catch  54  can be moved slightly sloping upwards in the direction of the lead-in chamfer  30 . This variant is advantageous if the containers stacked one atop the other are so close to one another onboard ships that they cannot be rotated about their vertical axis for the joining and/or separating of the containers during the loading and/or unloading of the containers. When the upper container  36  is placed on the lower container  35 , as before, the lead-in taper  29  on the lower coupling projection  23  is first inserted into the elongated hole  33 . Then, a lower slope sets down on the chamfer  32  at the elongated hole  33 . As a result of this, the locking catch  54  is pressed backwards against the force of a spring  55  and comes into the position shown by broken lines in  FIG. 16 . The lower coupling projection  23  can now slide into the elongated hole  33 . The locking catch  54  is then pushed back again by means of the force of the spring  55  into the starting position. The coupling piece is locked.  
         [0053]     In the coupling piece shown in  FIG. 16 , the locking catch  54  is concretely pushed back into the elongated hole  33  only during the loading of the container, i.e., during the insertion of the lower coupling projection  23  into the elongated hole  33 . Because of the upwardly sloping course of the direction of displacement of the locking catch, which corresponds approximately to the angle of the upper shoulder  34 , a force directed almost at right angles to the moving direction of the locking catch  54  occurs on the locking catch  54  during the unloading. Thus, the containers must be rotated slightly during unloading. However, it is guaranteed by this measure that the containers stacked one atop the other do not independently unlock due to forces acting on them while at sea. Difficulties possibly occurring during the unloading of the container because of containers standing close to one another take second place to safety during the transport onboard ships. At the same time, it can be seen that the course of the lower slope  56  compared to the direction of displacement of the locking catch  54  is slightly greater than a right angle. Consequently, an optimal force on the locking catch  54  is reached for pushing back during the loading.  
         [0054]     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.