DE10105785A1 - Locking device for cargo containers stacked one above the other on board ship, includes an abutment device for preventing swiveling of connector about a transverse axis - Google Patents

Abstract

A locking device for containers on board ship has a first coupling section (31) for engaging with a bottom corner element (34) of a top container (35) and a second coupling section (32) for locating with the top corner element of a bottom container (37). An abutment (43) prevents swiveling of the connection device (30) in the bottom corner element about a transverse axis, and can be moved out of a locking position in which it prevents movement about a transverse axis, into an unlocking position in which it allows movement about a transverse axis for the unlocked state.

Description

The invention relates to a device for locking one above the other Containers, especially on board ships, with a first Coupling section with a lower corner fitting of an upper container in Can be brought into engagement with a second coupling section, which is connected to an upper one Corner fitting of a lower container can be brought into engagement with a stop, which, in an assembled state, pivots the connecting device in prevented the lower corner fitting around a transverse axis, with a Locked state in which the second coupling section in the assembled state is firmly engaged with the upper corner fitting, and with an unlocked state, in which the second coupling section detachable from the upper corner section and with this can be brought into engagement.

When transporting and storing containers, especially on board Ships, these are usually stacked on top of each other. The individual containers stacked one on top of the other are connected to one another, thus slipping the individual containers against each other or an unwanted Lifting the containers from one another is prevented. Usually come with it semi-automatic rotating fittings, so-called twistlocks, are used. The individual containers have both on their underside and on their respective Top fittings on all four corners. The twistlocks connect after the Then assemble a lower corner fitting of an upper container with a the upper corner fitting of a lower container underneath.

The containers used for the transport are standardized. There are so-called 40- Foot containers and so-called 20-foot containers, of which exactly two with one standard 76 mm gap between them, just the length of a 40- Correspond to foot containers. This results when stowing the 20-foot container Problem that on the facing ends of the two 20-foot Container actuation of the twist locks due to the small joint width of 76 mm not possible. That is why the fittings arranged in the middle fully automatic center fittings, so-called midlocks. In particular On board ships, the fittings used to connect the individual Containers are constantly kept available for every type of loading. This means, two sets of fittings, namely twistlocks and midlocks, must be kept become. The result is that unwanted and unnecessary ballast is carried along must become. On the other hand, it can lead to inattentive stowing Confusion of midlocks and twistlocks come what is at least useless Working time consumed. In the worst case, namely when accidentally one  Twistlock has been used on a center fitting, it can happen that this twistlock can only be removed using a cutting torch.

To solve this problem, a device is described in DE 297 16 830 U1 specified, the second coupling section has a locking lug, which, similar to the latch on a snap lock, in the second Coupling section is displaceable. In DE 297 16 830 U1 is also a Device specified in which the second coupling section as a whole in the Device is pivotable. With these approaches, the problem arises that relatively delicate movable parts are used. When loading and The containers are stowed in a confined space using a container crane but often before that the individual containers touch each other, collide or streak together. Given the high weight of fully loaded containers then very large forces occur at the contact surfaces. Especially those in the lower corner fittings of the container already used Connecting devices protrude from the containers down and are exposed to extreme loads. The delicate adjustment facial expressions of the well-known Connecting devices can easily be damaged.

It is an object of the invention to provide a universal device for Locking stacked containers to indicate the easy can be mounted and the other hand robust and insensitive to mechanical Stress is.

The object is achieved in a device of the type mentioned at the outset by that the stop from a locked position in which it is for the locked state Prevents pivoting about the transverse axis, can be moved into an unlocked position, in which it allows pivoting about the transverse axis for the unlocked state. On in this way, the first coupling section and the second Coupling section are made in one piece. This results in a robust Component with a simple structure. The device can be taken as a whole from the Swivel the locked state into the unlocked state so that no separate ones Axes are required that are damaged by mechanical stress can. Rather, the invention is based on the knowledge that Moving a stop from a locked position to an unlocked position Freedom of movement, especially the vertical play, of the first Coupling section in the lower corner fitting can be enlarged so far that the entire device can be pivoted into the unlocked state.

A further development of the invention is characterized in that the stop is movable. In its locked position, the stop can be on the  Hit the housing of the upper container and thus swivel the Prevent device around the transverse axis. In its unlocked position, the strikes Then stop against the housing of the upper container and thus allows Swiveling the device around the transverse axis. In this way, the construction the device particularly simple.

In another development, the stop is pivotable. Because here however only the stop and not, as in the prior art, the second Coupling section is pivotable, can be a large mechanical Prevent loading of the moving parts during loading.

An actuating member is preferably provided for the stop. This Actuator can then move the stop in its Locked position and used in its unlocked position. This will make the Operation of the device facilitated.

The actuator can be a wire rope that can withstand pressure. In this case can be reached by pulling the wire rope and pressing the Wire rope the other position of the stop can be adjusted. Such one pressure-resistant wire rope is easy to manufacture and robust in operation.

Preferably, means for receiving the actuator for one Transport condition provided. This makes the actuator when loading reliably protected against damage.

For this purpose, the actuator for the transport state in the stop be insertable. In this case, the actuator is inserted Condition no longer before and is thus reliably protected against damage. At the same time, the structure is simple.

A tab can also be provided, under which the actuator for the Transport condition is clampable. Especially when using a pressure-resistant wire rope as an actuator is an advantage. The Transport condition can then be simply by bending and clamping of the wire rope under the tab.

Preferably, the actuator should be in the assembled state Extend the longitudinal direction of the container. This at least ensures that Actuator does not protrude laterally over the container.  

In a development of the invention, the stop on the locking position biased. This locks the stop in the assembled state of the Device automatically.

Another development of the invention is characterized by a spacer plate, which connects the first coupling section to the second coupling section, is integrally formed with these and in the assembled state between the upper container and the lower container is arranged. That gives Connection of the upper container to the lower container additional stability.

In this case, the tab is preferably formed on the spacer plate, which is a simple structure and an effective protection for the Actuator results.

In a development of the invention, the second coupling section has a Locking lug on that in the assembled state with the upper corner fitting of the lower container engages behind. This locking lug provides a reliable connection between the upper container and the lower one Container safe.

The locking lug should face the first coupling section Have a holding surface. This holding surface can take the required forces when connecting of the upper and lower container.

It is also advantageous if the locking lug is one of the first Has coupling section facing insertion surface. This insertion surface can reliable sliding of the locking lug into the upper corner fitting of the ensure the lower container during assembly.

In a development of the invention, the first coupling section at least one projection, which is parallel to the in the assembled state Transverse axis extends and with the lower corner fitting of the upper container intervening. This projection locks in easily the assembled state the lower corner fitting of the upper container on the first coupling section.

There are preferably two projections on two sides of the provided the first coupling section. This results in a special one secure and resilient connection.  

In a development of the invention, the stop is at least one cam in the assembled state with the lower corner fitting of the upper container intervening. Such a cam is easy to move and ensures a high holding force.

Preferably, the cam has at least one stop surface, which in the Locked position facing the second coupling section. By means of this The lower corner fitting of the upper container is then in the stop surface Locked position securely fixed to the first coupling section.

At least one additional stop surface should be provided on the cam, which in the unlocking position faces the second coupling section. Preferably is this further stop surface designed so that the pivoting movement of the Connection device is supported around the transverse axis.

In another development, the cam has a cutout that is in the Locked position takes up the projection. This results in a special one high load capacity of the cam because of the forces on the projection can be forwarded.

The following are exemplary embodiments of the invention with reference to the drawings explained in more detail. Show it:

Fig. 1 is a front view of a first apparatus having the inventive features, together with the section II-II through two interconnected container of Fig. 2,

Fig. 2 shows the section II of Fig. 1,

Fig. 3 is a view similar to FIG. 2 pushed back actuator,

Similar to FIG. 4 is an illustration of Fig. 2 with the first device in Entriegelzustand,

Fig. 5 is a view similar to FIG. 2, in which the upper container is a piece of wide lifted from the lower container,

That the device has come to the upper corner fitting of the lower container disengaged from Fig. 6 is a view similar to FIG. 5, in which the upper container has been lifted so far from the lower container,

Fig. 7 shows a second apparatus having the inventive features in a lock status in a partially sectioned view of section VIII-VIII of Fig. 8,

Fig. 8 shows the section VII-VII of Fig. 7,

Fig. 9 is a view similar to FIG. 7 in a Entriegelzustand the second device,

Fig. 10 shows the section IX-IX of Fig. 9, wherein the second device is illustrated in the uncut Entriegelzustand,

Fig. 11 is a view similar to FIG. 10, wherein the upper container is a piece of raised far enough

Fig. 12 is a view similar to FIG. 10, with some distance raised upper container,

Fig. 13 is a view similar to FIG. 11, wherein the upper container is raised so that the device is completely out of engagement with the upper corner fitting of the lower container,

Fig. 14 is a view similar to FIG. 12, in which the upper container is lifted so far that the second device is completely out of engagement with the upper corner fitting of the lower container,

Fig. 15 shows a third device having the features of the invention in an illustration similar to FIG. 1,

Fig. 16 shows the section XV-XV of Fig. 15,

Fig. 17 is a view similar to FIG. 15 in a Entriegelzustand the third device,

Fig. 18 is a view similar to FIG. 16 in the Entriegelzustand the third device,

FIG. 19 shows a representation similar to FIG. 17, the upper container being raised a little,

Fig. 20 is a view similar to FIG. 18 with a certain distance raised upper container,

In that the third device, Fig. 21 is a view similar to FIG. 19, wherein the upper container is lifted so far completely out of engagement with the upper corner fitting of the lower container,

Fig. 22 is a view similar to FIG. 20 with so far raised container, that the third device is completely out of engagement with the upper corner fitting of the lower container,

Fig. 23 is a further connection device having the features of the invention in an illustration similar to FIG. 1,

Fig. 24 shows the section XXIII-XXIII of Fig. 23,

Fig. 25 is an illustration similar to FIG. 23, wherein the actuating member is shown in a transport state,

Fig. 26 is a partial view of section XXVIII-XXVIII of Fig. 25 and

Fig. 27 is an illustration similar to Fig. 24 with the actuator in the transport state.

Fig. 1 shows a first device 30 with the inventive features. The first device 30 has a first coupling section 31 and a second coupling section 32 , which are connected to one another by means of a spacer plate 33 . The first coupling section 31 , the second coupling section 32 and the spacer plate 33 are made in one piece. The first coupling section 31 is engaged by a lower corner fitting 34 of an upper container 35 . The second coupling section 32 engages with an upper corner fitting 36 of a lower container 37 .

In Fig. 1, the corner fittings 34 , 36 are shown in section II-II of Fig. 2. The first connection device 30 is shown in an uncut front view.

The first coupling section 31 has projections 38 on two sides facing away from one another, which engage behind the lower corner fitting 34 .

FIG. 2 shows section II of FIG. 1. The first device 30 is shown in a locked state, in which the upper container 35 is firmly connected to the lower container 37 . The second coupling section 32 has a locking lug 39 which is hook-shaped. The locking lug 39 has on its side facing the first coupling section 31 a holding surface 40 with which it engages behind the upper corner fitting 36 . The locking lug 39 also has an insertion surface 41 on its side facing away from the first coupling section 31 , which is intended to facilitate the insertion of the second coupling section 32 into the upper corner fitting 36 . The insertion surface 41 runs obliquely. It is particularly domed. On the side facing away from the locking lug 39 , the second coupling section 32 has a further insertion surface 42 . The insertion surface 42 is also inclined, in particular curved, and is intended to facilitate the insertion of the second coupling section 32 into the upper corner fitting 36 .

A stop 43 is arranged facing the spacer plate 33 . A spring element 44 , in particular a helical spring 44 , is arranged between the spacer plate 33 and the stop 43 . The stop 43 is connected to an actuating member 45 , namely a pressure-resistant wire rope 45 , which has a handle 46 at its end facing away from the stop 43 . At its end facing the stop 43 , the actuating member 45 has a bolt 47 . The stop 43 has at its end facing away from the spacer plate 33 an opening 48 , namely a blind bore 48 , the cross section of which corresponds to that of the bolt 47 . The stop 43 has in its wall facing the spacer plate 33 a through opening 49 , the cross section of which corresponds to that of the actuating member 45 , namely the pressure-resistant wire rope 45 .

In the locked state shown in FIG. 2, the upper container 35 and the lower container 37 are firmly connected to one another. When lifting the upper container 35 , the holding surface 40 of the locking lug 39 strikes the upper corner fitting of the lower container 37 . As a result, a torque is exerted on the first connecting device 30 , as a result of which the stop 43 abuts against the lower corner fitting 34 of the upper container 35 . A pivoting movement of the first connecting device 30 about a transverse axis, which extends parallel to the direction of extension of the two projections 38 , is prevented in this way. The upper container 35 and the lower container 37 are thus firmly connected to one another by the first connecting device 30 .

FIG. 3 shows an illustration similar to FIG. 2, the actuating member 45 being in a transport state. To reach the transport state, the actuator 45 is pushed back. The handle 46 lies against the spacer plate 33 in FIG. 3. The bolt 47 is pushed back into the bore 48 of the stop 43 . In the transport state shown here, the actuator 45 does not protrude appreciably beyond the spacer plate 33 with its handle 46 . In particular, the actuating member 45 is arranged with its grip 46 protected between the lower corner fitting 34 and the upper corner fitting 36 . In this way, other containers cannot damage the actuator 45 or the handle 46 when stowed.

FIG. 4 shows the first connecting device 30 in a representation similar to FIG. 2. An unlocked state is shown in which the stop 43 is displaced with the actuating member 45 against the spring force of the helical spring 44 . The stop 43 is moved so far in the figure to the right that it no longer bumps against the lower corner fitting 34 .

FIG. 5 shows the first device 30 in the unlocked state in a representation similar to FIG. 4. The upper container 35 is lifted up to a certain extent. In the illustrated state, the holding surface 40 is in contact with the upper corner fitting 36 . By lifting the upper container 35, the upper corner fitting 36 acts on the holding surface 40 . As a result, a torque is exerted on the first device 30 . This torque causes the first device 30 to pivot about the transverse axis until the first device 30 itself abuts the lower corner fitting 34 with a surface facing the stop 43 .

FIG. 6 shows an illustration similar to FIG. 5 at a later point in time. The upper container 35 is moved so far up in the figure that the locking lug 39 has been completely released from the upper corner fitting 36 . With the displacement of the stop 43 against the biasing force of the coil spring 44 , the vertical play of the first device 30 at its rear end, that is to say the end facing the stop 43, is increased in such a way that the first device 30 can be pivoted so far about its transverse axis that the second coupling section 32 can disengage from the upper corner fitting 36 .

FIG. 7 shows a second device 50 with the features of the invention in a representation similar to FIG. 1. The device 50 is shown in a partially sectioned representation of section VIII-VIII of FIG. 8. The same components have the same reference numerals as in the first device 30 . The second device 50 is shown in the figure in a locked state. The second device 50 has a first coupling section 51 and a spacer plate 52 , which are connected to the second coupling section 33 .

The first coupling section 50 has projections 53 on its sides facing away from one another. A cam 54 is assigned to each of the projections 53 . The cams 54 are pivotally attached to a common axis 55 . The cams 54 are firmly connected to the axis 55 , so that the two cams 54 can be pivoted together.

FIG. 8 shows the section VII-VII from FIG. 7, the second device 50 being shown in an uncut side view. As can be seen from the figure, the spacer plate 52 has a recess 56 .

FIGS. 9 and Fig. 10 show the second device 50 in representations similar to those of Fig. 7 and Fig. 8. However, the second device 50 is shown in FIGS. 9 and 10 in a Entriegelzustand. In the figures, the cams 54 are pivoted upwards by actuating the actuating member 45 . In detail, the actuating member 45 is pulled out of the spacer plate 52 by pulling the handle 46 in the direction of the arrow.

In the unlocked state shown, the vertical play of the first coupling section 51 in the lower corner fitting 34 is increased. The lower corner fitting 34 can be moved upwards until it strikes the projections 53 .

Fig. 11 and Fig. 12 show the second device 50 in Entriegelzustand in a representation similar to Fig. 9 and 10. The upper container 35 is lifted until a piece. The projections 53 are already on the lower corner fitting 34 . The holding surface 40 presses in the illustrated state against the upper corner fitting 36 and thus causes the second device to pivot about its transverse axis. From Fig. 12 it can be seen that the lower corner fitting 34 can engage in the recess 56 in the illustrated state.

Fig. 13 and Fig. 14 show the second device 50 in a view similar to FIGS. 11 and 12. The upper container 35 has been raised still further in Fig. 13 and 14. The locking lug 39 is then completely released from the upper corner fitting 36 in the figures.

FIG. 15 shows a third device 57 with the features of the invention in a representation similar to FIG. 7. The same elements have the same reference numerals. The third device 57 has a first coupling section 58 . The first coupling section 58 has cams 59 on its two sides facing away from each other, which are pivotably attached to a common axis 60 . Similar to the cams 54 , the cams 59 are firmly connected to the axis 60 , so that they can be pivoted together. The third device 57 is shown in a locked state in FIG. 15.

FIG. 16 shows the section XV-XV of FIG. 15 in a representation similar to FIG. 8. As can be seen in FIG. 16, the cam 59 has a first stop surface 61 which faces the second coupling section 32 in the locking position shown is and rests on the lower corner fitting 34 . In addition, the cam 59 has a further stop surface 62 and an oblique stop surface 63 .

Fig. 17 and Fig. 18 show the third device 57 in a representation similar to FIGS. 15 and 16. In Figs. 17 and 18, the third device is however illustrated in a 57 Entriegelzustand. To achieve the unlocked state shown in the figures, the actuating member 45 is pulled out of the spacer plate 52 to the right by actuating the handle 46 in FIG. 18, as is indicated by an arrow. As a result, the cam 59 has been pivoted upwards into its position shown in the figure, as is also indicated by an arrow. In the unlocked state shown, the vertical play between the stop surface 62 , which in this unlocked state faces the second coupling section 32 , and the lower corner fitting 34 , so that the upper container 35 can be raised a little until the stop surface 62 comes into contact with the lower corner fitting 34 comes.

Fig. 19 and Fig. 20 show the third device 57 in a representation similar to FIGS. 17 and 18. The upper container has been raised far a piece 35, as is indicated by arrows. As a result, the stop surface 62 has come into contact with the lower corner fitting 34 . Then the holding surface 40 then comes into contact with the upper corner fitting 36 , as a result of which a torque has been exerted on the third device 57 . This has caused the third device 57 to pivot into the position shown in FIGS. 19 and 20. This pivoting was supported by the oblique stop surface 63 .

Fig. 21 and Fig. 22 show the third device 57 in illustrations similar to FIGS. 19 and 20. In the in the state of FIG. 21 and 22 of the upper container 35 has been raised still further. As a result, the locking lug 39 of the second coupling section 32 has been completely released from the upper corner fitting 36 .

FIG. 23 shows a further connecting device 64 in a representation similar to FIG. 15. The lower container 37 and the upper corner fitting 36 are not shown in FIG. 23. The further connecting device 64 essentially corresponds to the third connecting device 57 . The same elements are given the same reference numerals. The further connecting device 64 differs from the third connecting device 57 by the spacer plate 65 .

FIG. 24 shows the section XXIII-XXIII of FIG. 23 of the further connecting device 64 in a representation similar to FIG. 16. The spacer plate 65 has a tab 66 . The tab 66 is formed in one piece with the spacer plate 65 . In FIGS. 23 and 24, the further connecting device is shown in an operating state 64 in which the cam 59 can be pivoted to the actuating member 45 upwards, by operating the handle chip 46.

FIG. 25 shows the further connecting device 64 in a representation similar to FIG. 23. FIG. 25 shows a transport state of the actuating member 45 . The actuator 45 is clamped behind the tab 66 , as indicated by an arrow in the figure.

Fig. 26 shows the section XXVIII-XXVIII of Fig. 25. As can be seen in the figure, the actuator 45 and the handle 46 is clamped behind the tab 66 so that it is good for providing the transport state of the spacer plate 65 and not is protected in the Fig. 34 26 lower corner fitting shown. Damage to the actuating member 45 and the handle 46 by streaking when stowing and moving the container 35 is thus reliably prevented.

FIG. 27 shows the further device 64 in the transport state in a representation similar to FIG. 24. It can be seen that the actuating member 45 and the handle 46 do not protrude to the right over the lower corner fitting 34 in the figure.

The spacer plate 65 with the tab 66 of the further device 64 can also be used in the second device 50 or the third device 57 . Likewise, the use of clamping the actuating member 45 behind a tab 66 for establishing the transport state can also be used in the first device 30 .

LIST OF REFERENCE NUMBERS

30

first device

31

first coupling section

32

second coupling section

33

spacer plate

34

lower corner fitting

35

upper container

36

upper corner fitting

37

lower container

38

head Start

39

locking tab

40

holding surface

41

lead-in

42

lead-in

43

attack

44

coil spring

45

actuator

46

grip

47

bolt

48

drilling

49

Through opening

50

second device

51

first coupling section

52

spacer plate

53

head Start

54

cam

55

axis

56

recess

57

third device

58

first coupling section

59

cam

60

axis

61

stop surface

62

stop surface

63

sloping stop surface

64

further device

65

spacer plate

66

flap

Claims (21)

1. Device for locking stacked containers ( 35 , 37 ), in particular on board ships, with a first coupling section ( 31 , 51 , 58 ) which can be brought into engagement with a lower corner fitting ( 34 ) of an upper container ( 35 ) , with a second coupling section ( 32 ) which can be brought into engagement with an upper corner fitting ( 36 ) of a lower container ( 37 ), with a stop ( 43 , 54 , 59 ) which, in an assembled state, pivots the connecting device ( 30 , 50 , 57 , 64 ) in the lower corner fitting ( 34 ) around a transverse axis, with a locked state in which the second coupling section ( 32 ) is firmly engaged with the upper corner fitting ( 36 ) in the assembled state, and with a Unlocked state in which the second coupling section ( 32 ) can be detached from and brought into engagement with the upper corner fitting ( 36 ), characterized in that the stop ( 43 , 54 , 59 ) consists of a lock gel position in which it prevents pivoting about the transverse axis for the locked state, can be moved into an unlocked position in which it permits pivoting about the transverse axis for the unlocked state. 2. Device according to claim 1, characterized in that the stop ( 43 ) is displaceable. 3. Device according to claim 1, characterized in that the stop ( 54 , 59 ) is pivotable. 4. Device according to one of the preceding claims, characterized by an actuating member ( 45 ) for the stop ( 43 , 54 , 59 ). 5. The device according to claim 4, characterized in that the actuating member is a pressure-resistant wire rope ( 45 ). 6. The device according to claim 4 or 5, characterized by means ( 48 , 66 ) for receiving the actuating member ( 45 ) for a transport state. 7. The device according to claim 6, characterized in that the actuating member ( 45 ) for the transport state in the stop ( 44 ) can be inserted. 8. Device according to claims 6 or 7, characterized by a tab ( 66 ) under which the actuating member ( 45 ) can be clamped for the transport state. 9. Device according to one of claims 4 to 8, characterized in that the actuating member ( 45 ) extends in the assembled state in the longitudinal direction of the container ( 35 , 37 ). 10. Device according to one of the preceding claims, characterized in that the stop ( 43 ) is biased to the locking position. 11. The device according to any one of the preceding claims, characterized by a spacer plate ( 33 , 52 , 65 ) which connects the first coupling section ( 31 , 51 , 58 ) to the second coupling section ( 32 ), is integrally formed with these and in the assembled State between the upper container ( 35 ) and the lower container ( 37 ) is arranged. 12. The apparatus according to claim 11, characterized in that the tab ( 66 ) is formed on the spacer plate ( 65 ). 13. Device according to one of the preceding claims, characterized in that the second coupling section ( 32 ) has a locking lug ( 39 ) which, in the assembled state, engages behind the upper corner fitting ( 36 ) of the lower container ( 37 ). 14. The apparatus according to claim 13, characterized in that the locking lug ( 39 ) has a holding surface ( 40 ) facing the first coupling section ( 31 , 51 , 58 ). 15. The apparatus according to claim 13 or 14, characterized in that the locking lug ( 39 ) has an insertion surface ( 41 ) facing away from the first coupling section ( 31 , 51 , 58 ). 16. Device according to one of the preceding claims, characterized in that the first coupling section ( 31 , 51 ) has at least one projection ( 38 , 53 ) which extends in the assembled state parallel to the transverse axis and with the lower corner fitting ( 34 ) of the upper container ( 35 ) engages behind. 17. The apparatus according to claim 16, characterized by two projections ( 38 , 53 ) on opposite sides of the first coupling section ( 31 , 51 ). 18. Device according to one of claims 3 to 17, characterized in that the stop is at least one cam ( 54 , 59 ) which in the assembled state engages with the lower corner fitting ( 34 ) of the upper container ( 35 ) engaging behind. 19. The apparatus according to claim 18, characterized in that the cam ( 54 , 59 ) has at least one stop surface ( 61 ) which faces the second coupling section ( 32 ) in the locked position. 20. The apparatus according to claim 19, characterized by at least one further stop surface ( 62 , 63 ) which faces the second coupling section ( 32 ) in the unlocked position. 21. Device according to one of claims 18 to 20, characterized in that the cam ( 54 ) has a recess which receives the projection ( 53 ) in the locked position.