In order to provide, as straightforwardly as possible, a trailer coupling comprising a ball neck which can be moved between an operating position and a rest position and has a pivot-bearing body disposed at a first end and a coupling ball disposed at a second end, also comprising a vehicle-mounted pivot-bearing unit in which the pivot-bearing body is accommodated such that it can be pivoted about a pivot axis between the operating position and the rest position, and further comprising a rotation-blocking device having at least one rotation-blocking body, which can be moved in a guide direction with at least one component in the radial direction in relation to the pivot axis, it being possible for the rotation-blocking body to be engaged with, and disengaged from, a receiving space by movement in the guide direction, and having an actuating body which has a wedge surface running transversely to the guide direction, can be moved in an actuating direction and the movement of which in the actuating direction can move, and force, the at least one rotation-blocking body in the guide direction, it is proposed that the rotation-blocking device comprises at least two rotation-blocking bodies, and that the rotation-blocking bodies can be moved in the respective guide direction by a common actuating body.

This patent application claims the benefit of German Application No. 10 2005 032 474.6, filed Jul. 7, 2005, the teachings and disclosure of which are hereby incorporated in its entirety by reference thereto.

BACKGROUND OF THE INVENTION

The invention relates to a trailer-coupling arrangement comprising a ball neck which can be moved between an operating position and a rest position and has a pivot-bearing body disposed at a first end and a coupling ball disposed at a second end, also comprising a vehicle-mounted pivot-bearing unit in which the pivot-bearing body is accommodated such that it can be pivoted about a pivot axis between the operating position and the rest position, and further comprising a rotation-blocking device having at least one rotation-blocking body, which can be moved in a guide direction with at least one component in the radial direction in relation to the pivot axis, it being possible for the rotation-blocking body to be engaged with, and disengaged from, a receiving space disposed on the pivot-bearing body by movement in the guide direction, and having an actuating body which has a wedge surface running transversely to the guide direction, can be moved in an actuating direction and the movement of which in the actuating direction can move, and force, the at least one rotation-blocking body in the guide direction.

Such a trailer coupling is known from EP 1 040 020.

Taking this prior art as the departure point, it is an object of the invention to provide a trailer coupling with as straightforward a construction as possible.

SUMMARY OF THE INVENTION

In the case of a trailer coupling of the type described in the introduction, this object is achieved according to the invention in that the rotation-blocking device comprises at least two rotation-blocking bodies, and in that the rotation-blocking bodies can be moved in the respective guide direction by a common actuating body.

The advantage of the solution according to the invention may be seen in the fact that it provides a straightforward possibility of achieving a rotation-blocking action which withstands the high loading of the ball neck.

It is even more advantageous if the rotation-blocking device comprises at least three rotation-blocking bodies.

A particularly advantageous solution provides that the rotation-blocking bodies are disposed relative to the actuating body such that at least their reaction forces which are directed transversely to the pivot axis and act on the actuating body compensate one another at least in part.

Such a solution thus has the advantage that the actuating body need not be designed such that it has to be mounted in a stable manner in order to absorb the reaction forces to which it is subjected by the rotation-blocking bodies; rather, it can be mounted very straightforwardly if the reaction forces to which the actuating body is subjected by the rotation-blocking bodies cancel one another at least in part.

It is particularly advantageous here if the rotation-blocking bodies are disposed relative to the actuating body such that at least their reaction forces which are directed transversely to the pivot axis and act on the actuating body substantially cancel one another.

It is particularly advantageous if the rotation-blocking bodies are disposed relative to the actuating body such that their reaction forces which act on the actuating body cancel one another at least in part.

It is possible here, in principle, for the rotation-blocking bodies to be disposed in any desired manner relative to the actuating body.

An exemplary embodiment here provides that the rotation-blocking bodies are disposed around the actuating body. Such a solution makes it possible, on the one hand, to dispose the rotation-blocking bodies in a space-saving manner and, on the other hand, to compensate at least in part the reaction forces which act on the actuating body.

Such a set-up is particularly advantageous when the rotation-blocking bodies are disposed substantially symmetrically in relation to a plane running perpendicularly to the pivot axis.

In order to fix the pivot-bearing body in terms of rotation, as far as possible, in a play-free manner, it is preferably provided that at least two of the rotation-blocking bodies interact with the receiving spaces provided for them such that the pivot-bearing body is thereby subjected to torques acting in opposite directions to one another.

These two torques acting in opposite directions to one another make it possible for the pivot-bearing body to be fixed in a play-free manner by the pivot-bearing unit.

No more specific details have been given up to now in respect of the movements of the actuating body for the purpose of moving the rotation-blocking bodies.

It would thus be conceivable, for example, to displace the actuating body in the direction of the pivot axis and, on account of this displacement of the actuating body, to move the rotation-blocking bodies in the guide direction.

A solution which is advantageous from the point of view of compactness provides that the actuating body is disposed such that it can be rotated about the pivot axis.

It is particularly advantageous here if the actuating body has wedge surfaces which extend over an angular region around the pivot axis, vary in terms of radial spacing from the pivot axis and can act on the rotation-blocking bodies.

Furthermore, no details have been given, in conjunction with the prior description of the solution according to the invention, as to how the rotation-blocking bodies, for their part, are to be guided in the guide direction.

It would be conceivable, for example, to guide the rotation-blocking body by a guiding accommodating region in the pivot-bearing body and to provide stationary receiving spaces with which the at least one rotation-blocking body can be engaged, or from which it can be disengaged.

It is particularly advantageous, however, if the rotation-blocking body is guided by a guide body which follows the pivot-bearing body in the radial direction.

The guide body is preferably formed here such that it has a guide sleeve with the guiding accommodating region for the respective rotation-blocking body.

A guide body which is provided in this way can also advantageously be used, in particular, in that a bearing for the actuating body is connected to the guide body, so that the actuating body can thus be mounted in a straightforward and advantageous manner.

It is likewise the case that no more specific details have been given up to now in respect of the mounting of the pivot-bearing body itself in the pivot-bearing unit.

Thus, in particular, an advantageous solution provides that the guide body forms a pivot bearing for the pivot-bearing body, so that the guide body, in addition to the guiding function, has the further advantage of performing the bearing function for the pivot body.

The guide body is suitably disposed here such that it is part of the vehicle-mounted pivot-bearing unit.

Within the framework of the solution according to the invention, different possible ways of disposing the guide body, pivot-bearing body and actuating body relative to one another are conceivable.

One conceivable solution would thus be one in which the actuating body encloses the guide body and the pivot-bearing body is enclosed by the guide body, that is to say engages in the guide body.

A further advantageous solution, however, provides that the actuating body is enclosed by the guide body, and that the pivot-bearing body engages around the guide body.

In respect of as straightforward a design as possible, as an alternative or as a supplement to the exemplary embodiments which have been described up to now, the object which was mentioned in the introduction is achieved according to the invention, in the case of a trailer coupling of the type described in the introduction, in that the pivot-bearing body forms an outer body which encloses the pivot-bearing unit on the outside and is disposed in relation to the pivot-bearing unit such that it cannot be displaced in the direction of the pivot axis.

Disposing the pivot-bearing body in this way has the advantage, on the one hand, of an advantageous spatial construction for the pivot-bearing unit itself and, on the other hand, of relatively straightforward sealing for the pivot-bearing unit, since the pivot-bearing body does not execute any movements in the axial direction of the pivot axis.

Seals which run around the pivot axis are preferably provided between a housing of the pivot-bearing unit and the two end sides of the outer body and provide sealing against the ingress of dirt and moisture.

In respect of the stability and also of the small amount of space required by the trailer coupling according to the invention, a particularly advantageous exemplary embodiment provides that the first end of the ball neck is attached to the outer body.

This makes it possible to provide a particularly straightforward and stable connection between the pivot-bearing body and the ball neck, likewise without increasing the amount of space required.

No more specific details have been given up to now in respect of the movement of the rotation-blocking bodies by the actuating body. It is thus provided, in the case of an advantageous solution, that the rotation-blocking bodies can be moved from a release position into a blocking position by the actuating body.

The actuating body is preferably formed here such that, in an inactive position, it allows the release position of the rotation-blocking bodies.

In addition, a further embodiment of the actuating body provides that, in an active position, this actuating body retains the rotation-blocking bodies in their blocking position.

In order, then, to ensure that the rotation-blocking bodies always pass into their blocking position, in particular when there is no actuation by the actuating body, it is preferably provided that the actuating body is forced in the direction of its active position by an elastic energy store.

In order for it to be possible for the actuating body to be actuated in a suitable manner, an actuating arrangement by means of which the actuating body can be moved from the active position into the inactive position is preferably provided.

The actuating arrangement is advantageously formed here such that the actuating body can be moved, by this actuating arrangement, counter to the direction in which it is forced by the energy store.

In the case of a rotatable actuating body, it is provided that the actuating arrangement can be used to rotate the actuating body counter to the direction of rotation which is brought about by the energy store.

No more specific details have been given up to now in respect of the formation of the actuating arrangement. An advantageous solution thus provides that the actuating arrangement has a drive element which is coupled to the actuating body.

Such a coupling between the drive element and the actuating body may be formed in a wide variety of different ways. One solution would be a direct connection between the drive element and the actuating body.

It is particularly advantageous, however, if the drive element and the actuating body are coupled to one another via a carry-along coupling device.

Such a carry-along coupling device may be formed in a wide variety of different ways. An advantageous embodiment provides that the carry-along coupling device has a free-travel state, in which there is no carry-along action, and a carry-along state.

One embodiment of a trailer coupling according to the invention provides that the carry-along coupling device is formed such that, starting from a starting position, movement of the drive element brings about movement of the actuating body in an intermediate position, only following passage through a free-travel state and once the carry-along state has been reached.

In order for the actuating arrangement always to be retained in a defined state even without being subjected to any action, it is provided that the actuating arrangement is formed such that it passes automatically into a starting position.

This can be realized particularly advantageously when the drive element of the actuating arrangement is forced in the direction of its starting position by an elastic energy store.

No information has been given, in conjunction with the prior explanation of the individual exemplary embodiments as to how the active position of the actuating body is to be reliably secured.

A particularly advantageous solution thus provides that the actuating body can be blocked by a safety device.

A particularly advantageous solution is one in which the actuating body can be blocked by the safety device against reaching its inactive position, in order to ensure that the actuating body never automatically allows the release position of the rotation-blocking bodies, for example in the event of a failure of the elastic energy store, which forces the actuating body in the direction of its active position.

Such a safety device is formed such that it requires action in order to eliminate the blocking of the actuating body.

For this reason, it is suitably provided that the actuating arrangement is coupled to the safety device, so that release of the blocking of the actuating body by the safety device can also be eliminated via the actuating arrangement.

The safety device is preferably coupled to the actuating arrangement here such that the safety device blocks any movement of the actuating body which is not initiated by actuation.

In particular, the safety device is formed such that, when the actuating arrangement is not actuated, it blocks movement of the actuating body into its inactive position.

A suitable solution here provides that the drive element of the actuating arrangement is coupled to the safety device.

The drive element may suitably be formed here such that the action to which the actuating body is subjected and the action to which the safety device is subjected are coordinated with one another via the drive element, so that actuation of the actuating arrangement, on the one hand, results in the blocking of the actuating body being eliminated and, on the other hand, results in the actuating body being moved from the active position into the inactive position.

It is provided for this purpose, for example, that, as it moves from the starting position into an intermediate position, the drive element transfers the safety device from the securing position into the disengaged position.

A wide variety of different possibilities are conceivable for the coupling between the drive element and the safety device.

For example, any type of coupling, for example even via an electric control means, would be conceivable.

A solution which is particularly expedient on account of its simplicity here provides that the drive element and the safety device are coupled to one another via a mechanical coupling device.

The mechanical coupling device is advantageously formed such that it uses a guide track to control the action to which the safety device is subjected.

Further features and advantages of the invention form the subject matter of the following description and of the illustration of a number of exemplary embodiments.

DETAILED DESCRIPTION OF THE INVENTION

A first exemplary embodiment of a trailer coupling according to the invention, illustrated inFIG. 1in an operating position A and inFIG. 2in a rest position R, comprises a ball neck which is designated as a whole by10, is mounted on a pivot-bearing body14by way of a first end12and, at a second end16, carries a coupling ball which is designated as a whole by18and on which a coupling-ball receiver of a trailer can be fixed.

The pivot-bearing body14is mounted such that it can be pivoted about a pivot axis22relative to a vehicle-mounted carrier24by a pivot-bearing unit which is designated as a whole by20, the carrier24preferably having a carrying plate26which holds the pivot-bearing unit20, preferably extends in a plane perpendicular to the pivot axis22and has a vehicle-mounted transverse carrier28, which can be secured in a known manner at the tail of a vehicle body, to be precise such that the pivot-bearing unit20and the carrier24are located on that side of a lower edge30of a bumper unit36which is directed away from a carriageway surface and are covered by the bumper unit36(FIG. 3).

In the operating position, which is illustrated inFIG. 1, the ball neck10engages, by way of a portion32which follows the first end12, beneath the lower edge30of the bumper unit36, so that the second end16and the coupling ball18together with a plug receptacle34are located on a side of the rear bumper unit36which is directed away from the vehicle body, whereas in the rest position, both the pivot-bearing unit20and the ball neck10as a whole together with the coupling ball18are covered from view from the rear by the rear bumper unit36.

As is illustrated inFIGS. 4 and 5, the pivot-bearing unit20comprises a guide body40, which is fixedly connected to the carrying plate26by way of a flange42, and a guide sleeve44, which, starting from the flange42, extends away from the carrying plate26and on which the pivot-bearing body14is mounted in a rotatable manner. For this purpose, the guide sleeve44comprises a cylindrical outer lateral surface46, on which the pivot-bearing body14is located by way of a cylindrical inner surface48and thus undergoes rotary guidance about the pivot axis22, so that the pivot-bearing body14can be rotated relative to the guide body such that the ball neck10can be pivoted from the operating position A into the rest position R and vice versa.

By virtue of its fixed connection to the carrier plate26and the carrier24, the guide body40thus forms the vehicle-mounted rotary mounting for the pivot-bearing body14.

In order to fix the pivot-bearing body14in the operating position A and the rest position R, the pivot-bearing unit20is provided with a rotation-blocking device which is designated as a whole by50and has an actuating body52and a plurality of rotation-blocking bodies54, which can be activated by the actuating body52and are guided in guiding accommodating regions56of the guide sleeve44such that they can be moved in a guide direction57running substantially radially in relation to the pivot axis22, and also has first receiving spaces58and second receiving spaces60which extend into the pivot-bearing body14, starting from the inner surface48of the latter, and with which the rotation-blocking bodies can be brought into engagement in the operating position A and in the rest position R, respectively, the receiving spaces58,60having wall surfaces59,61which are increasingly less spaced apart from one another in the radial direction in relation to the pivot axis22.

If, for example, the rotation-blocking device50, as is illustrated for the first exemplary embodiment in conjunction withFIGS. 4 and 5, comprises a set of three rotation-blocking bodies54a,54band54c, then the guide sleeve44has a set of three guiding accommodating regions56a,56band56c, in which the rotation-blocking bodies54a,54band54care guided such that they can be displaced in the guide direction57, which runs substantially radially in relation to the pivot axis22, and the pivot-bearing body14is provided with a set of first receiving spaces58a,58band58c, with which the rotation-blocking bodies54a,54band54ccan be brought into engagement in the operating position A, and with a set of second receiving spaces60a,60band60cwith which the rotation-blocking bodies54a,54band54ccan be brought into engagement in the rest position R.

In order for the rotation-blocking bodies54to be suitably moved and positioned in the guide direction57, the actuating body52is provided with a set of, in total, three retraction receiving spaces62a,62band62cand three pressure-exerting surfaces66a,66band66c, which follow the retraction receiving spaces62a,62b,62cin a rotational direction64, it being possible for the rotation-blocking bodies54, in their release position, to penetrate into the retraction receiving spaces62a,62b,62cto the extent where they no longer project beyond the outer lateral surface46of the guide sleeve44, and the pressure-exerting surfaces66a,66b,66cextending radially outward in relation to the pivot axis22to an increasing extent, as they progress in the rotational direction64, in each case from a radially inner initial region68a,68band68c, which immediately follows the respective retraction receiving spaces62, up to a respective radially outer end region70a,70band70cand thus, during a rotary movement of the actuating body52, acting as wedge surfaces on the rotation-blocking bodies54in order to move the latter into their blocking position.

The pressure-exerting surfaces66here preferably run as helical or involute segments relative to the pivot axis22.

In order either to retain the rotation-blocking bodies54in their blocking position, by subjecting them to the action of the pressure-exerting surfaces66between the initial region68and the end region70, or to allow them to penetrate into the retraction receiving space62in the release position, the actuating body52can likewise be rotated about the pivot axis22, in particular coaxially in relation to the latter, to be precise such that the set of retraction receiving spaces62a,62band62cis directed toward the rotation-blocking bodies54and makes it possible for the latter, as is illustrated inFIGS. 6 and 7, in the inactive position, to penetrate into the retraction receiving spaces62in the radial direction in relation to the pivot axis22, in order to allow the respective rotation-blocking bodies54to release the first receiving spaces58or the second receiving spaces60in respect of rotation together with the pivot-bearing body14about the pivot axis22, so that the pivot-bearing body14, with the ball neck10, can be rotated freely, without obstruction, relative to the guide sleeve44, as is illustrated inFIGS. 6 and 7, the rotation-blocking bodies54in this case not extending beyond the outer lateral surface46of the guide sleeve44.

In the case of rotation-blocking bodies54being seated in the retraction receiving spaces62, rotation of the actuating body52in a direction of rotation72counter to the rotational direction64causes the rotation-blocking bodies54to be moved out of the retraction receiving spaces62and in the first instance, as is illustrated inFIGS. 8 and 9, in the active position of the actuating body52, to be seated on the initial regions68of the pressure-exerting surfaces66, albeit penetrating, for example, into the first receiving spaces58and thus preventing the pivot-bearing body14from being able to rotate freely.

If the actuating body52is rotated further in the direction of rotation72, counter to the rotational direction64, then the rotation-blocking bodies54are subjected to the action of regions of the pressure-exerting surfaces66which are located further and further outward in the radial direction in relation to the pivot axis22, these regions thus pushing the rotation-blocking bodies54to an increasing extent, for example in the operating position A of the ball neck10, into the first receiving spaces58a,58band58c, in order thus for the pivot-bearing body14to be fixed in a substantially play-free manner relative to the guide body40, in this case to the guide sleeve44. In this blocking position of the rotation-blocking bodies54, the actuating body52is located in its active position such that the rotation-blocking bodies54, as is illustrated inFIGS. 4 and 5, are seated approximately on central regions76, located between the initial regions68and the end regions70, of the pressure-exerting surfaces66and are acted on by the same.

The play-free locking of the pivot-bearing body14by the rotation-blocking bodies54can be achieved particularly advantageously when the rotation-blocking bodies54and the receiving spaces58and60are configured such that, as one of the rotation-blocking bodies54penetrates to an increasing extent into one of the receiving spaces58or60and the rotation-blocking bodies54engage against one side of the receiving spaces58and60, rotation of the pivot-bearing body14is brought about and the set of rotation-blocking bodies54ato54c, for the purpose of fixing the pivot-bearing body14in a play-free manner, subjects the receiving spaces58or60to torques90,92acting in opposite directions.

As is illustrated, for example, inFIGS. 10 to 13, the rotation-blocking body54bhas its lateral surface84bengaging just against one side86bof the guiding accommodating region56b, for example the side which is located in the rotational direction64, and is supported by an opposite region of its lateral surface84bon a side88bof the receiving space58bwhich is located counter to the rotational direction64, increasing movement of the rotation-blocking body54in the radial direction in relation to the pivot axis22resulting in a torque90which acts, counter to the rotational direction64, on the pivot-bearing body14.

Furthermore, the rotation-blocking body54chas its lateral surface84cengaging against a side86cof the guiding accommodating region56cwhich is located counter to the rotational direction, and has an opposite region of the lateral surface84cacting on one side89cof the first receiving space58c, this resulting in a torque92which acts, in the rotational direction64, on the pivot-bearing body14.

The torques90and92produced by the rotation-blocking bodies54band54cthus act, as is illustrated inFIG. 10, in opposite directions to one another and allow the pivot-bearing body14to be secured in a play-free manner relative to the guide body40, in particular to the guide sleeve44of the same, since the engagement of one side of the rotation-blocking bodies54, on the one hand, in the guiding accommodating region56and, on the other hand, in the first receiving space58, eliminates the play between the guiding accommodating region56and the rotation-blocking body54and the first receiving space58in the region of the two rotation-blocking bodies54band54c.

Furthermore, as is illustrated inFIG. 13, it is provided in the case of the rotation-blocking body54athat the latter has its lateral surface80aengaging both against the side88aof the first receiving space58awhich is located in the rotational direction64and against the side89aof the first receiving space58awhich is located opposite this side88a, and thus, depending on the production tolerance in the region of the guiding accommodating region56aand of the corresponding receiving space58a, and depending on the loading of the ball neck10in trailer operation, usually contributes to one of the two torques90and92and thus usually also serves, in addition to the rotation-blocking body54bor54cloaded by the ball neck10, to absorb load, although a state in which the rotation-blocking body54acannot contribute to either of the two torques90and92is also possible.

In order to make it possible for the actuating body52to act on each of the three rotation-blocking bodies54to the optimum extent in each case, it is provided that, in the active position, the actuating body52is centered in accordance with the position of the rotation-blocking bodies54, and the actuating body52, as is illustrated inFIGS. 4,6and8, is thus mounted on a guide pin100by way of a central bore96, via an interspace98, so that, on account of the play relative to the guide pin100which is produced by the interspace98, the actuating body52can center itself in accordance with the production-tolerance-induced position of the rotation-blocking bodies54within the guide body40, it being possible for the self-centering of the actuating body52to deviate slightly from a coaxial arrangement in relation to the guide pin100and thus in relation to the geometrical pivot axis22.

On account of the self-centering, the rotation-blocking bodies54a,54band54csubject the receiving spaces58a,58band58cor60a,60band60cto approximately equal forces Ka, Kb and Kc in the respective guide direction57a,57band57c, so that the reaction forces RKa, RKb and RKc acting on the actuating body52are also approximately equal.

In the case of the illustrated exemplary embodiment of the solution according to the invention, the rotation-blocking bodies54are disposed in the guiding accommodating regions56at equal angular spacings around the pivot axis22, so that the reaction forces RKa, RKb, RKc on one of the rotation-blocking bodies54a,54b,54c, these reaction forces being approximately equal as a result of the self-centering, act equally on the other rotation-blocking bodies54band54c,54aand54cand54aand54band thus cancel one another overall, so that the actuating body52is in a state of force equilibrium and does not require any additional support.

The rotation-blocking bodies54, as is illustrated inFIGS. 4,6and8, are preferably formed as rollers, in particular circular-cylindrical rollers, which thus engage, on the one hand, linearly against the actuating body52and, on the other hand, also linearly against the receiving spaces58or60. In this case, the receiving spaces58,60are formed as depressions which have a constant cross-sectional shape in the direction parallel to the pivot axis22, the cross-sectional shape being based more or less on part of a circle.

For this reason, the interspace98is also selected to be of such a magnitude that the actuating body52can even execute a slight rocking movement relative to the geometrical pivot axis22and can thus adapt itself to the linear engagement of all three rotation-blocking bodies54against all three receiving spaces58or60in each case.

The guide pin100thus provides just very rough rotatable mounting of the actuating body52relative to the pivot axis22, this mounting being relevant primarily when the actuating body52retains the rotation-blocking bodies54in a release position, in which the rotation-blocking bodies54penetrate into the retraction receiving spaces62of the actuating body52.

In order for the actuating body52always to move such that the rotation-blocking bodies54move in the direction of the blocking position, the actuating body52is subjected to the action of a torsion spring102which, on the one hand, acts on the actuating body52and, on the other hand, is supported on the guide body40.

The torsion spring also results in the situation where the actuating body52, under the action of force, pushes the rotation-blocking bodies54into the receiving spaces58or60, and the pivot-bearing body is thus fixed in a play-free manner, the freedom from play also being maintained, in the case of the geometry of the receiving spaces58,60changing on account of the loading during operation, by the actuating body52rotating further in the direction of rotation72.

The guide body40preferably extends, by way of its guide sleeve44, up to a cover104which, on a side which is located opposite the flange42, closes off an inner space106enclosed by the guide sleeve44.

In the inner space106, the torsion spring102follows the cover104, and the torsion spring is followed by the actuating body52, which extends through the entire guide sleeve44and the flange42and a through-passage108in the carrier plate26.

Furthermore, the guide pin100is provided with an end threaded portion112and is screwed, by way of the latter, into a threaded bore114in the cover104, so that the guide pin100is kept oriented coaxially in relation to the pivot axis22by the cover104.

Moreover, the guide sleeve44has, following the cover104, on the outside, a threaded portion116, which is set back radially in relation to the outer lateral surface46and onto which a retaining ring120can be screwed, this retaining ring, together with the flange42, forming an axial guide for the pivot-bearing body14. The pivot-bearing body14is thus guided between the screwed-on retaining ring120and the flange42in respect of movement in the direction of the pivot axis22, end surfaces122and124of the pivot-bearing body14engaging with sliding action against annular surfaces126and128of the flange42and of the retaining ring120, respectively.

For the purpose of sealing the pivot-bearing body14, which can be rotated relative to the guide body40, in relation to the guide body, both the flange42and the retaining ring120are each provided with an all-round seal132,134, respectively, which each engage with sliding action against the end surfaces122,124by way of respective lips136and138, so that the pivot-bearing unit20is sealed against the ingress of moisture and dirt during a pivoting movement of the ball neck10with the pivot-bearing body14.

In order for it to be possible to move the actuating body52from the active position into the inactive position counter to the force of the torsion spring102, an actuating arrangement which is designated as a whole by150is provided.

As is illustrated inFIGS. 4,6and8, this actuating arrangement150comprises a rotary drive element152which can be rotated relative to the actuating body52, and is likewise mounted in a rotatable manner on the guide pin100.

As is illustrated inFIGS. 4,6and8, the rotary drive element152comprises a pull-cable rest154on which a pull cable156rests, this cable, as is illustrated inFIG. 3, being guided, via a cable pull158, to an actuating element, for example an actuating handle, which will not be described any more specifically.

The pull cable156here, as is likewise illustrated inFIG. 3, is fixed on the rotary drive element152by an end bearing body162and, starting from the bearing body162, extends over the pull-cable rest154, which is provided on the rotary drive element152.

As is illustrated inFIG. 14, the rotary drive element152is coupled to the actuating body52via carry-along devices164,166, the carry-along devices164and166—as is described hereinbelow—being connected to the rotary drive element152such that, starting from a starting position, the latter can rotate freely to a limited extent relative to the actuating body52without acting on the carry-along devices164,166, and it is only when a carry-along position is reached that rotation of the actuating body52, driven by the rotary drive element152, takes place.

The reason for this is that the rotary drive element152does not just serve for causing the actuating body52to rotate from its fixing position into the release position; rather, it also serves, at the same time, to move a rotation-prevention means170for the actuating body52, this means being illustrated inFIG. 3, from a securing position into a disengaged position.

As is illustrated inFIGS. 15 to 18, the rotation-prevention means170comprises a securing lever172which is mounted on a bearing journal174, which is fixed relative to the carrier plate26, such that it can be pivoted about an axis176, the securing lever172extending in a plane178which runs approximately parallel to the pivot axis22.

The securing lever172is provided with a bearing portion180which has the bearing journal174passing through it, and, starting from the bearing portion180, the securing lever extends, by way of a bracket portion182, to a securing portion184which, as is illustrated inFIGS. 17 and 18, engages in the through-passage108of the carrying plate26, to be precise such that the securing portion184is located in the region of one of the retraction receiving spaces62if the actuating body52is located in its active position. The securing portion184thus prevents rotation of the actuating body52such that the rotation-blocking bodies54can enter into one of the retraction receiving spaces62and pass into their release position.

In particular, the securing portion184is located such that, in the case of a rotary movement of the actuating body52, a step186which is provided at the transition between the retraction receiving spaces62and the preceding pressure-exerting surface66, as seen counter to the rotational direction64, would run against the securing portion184as long as the securing lever172is located in its securing position. This securing position is maintained by a torsion spring188acting on the securing lever.

In order to pivot the securing lever172out of the securing position, the rotary drive element152, as is illustrated inFIG. 15, is provided with an actuating cam190, which interacts with an actuating nose192on the securing lever172.

The actuating cam190here comprises a first bearing surface194, on which the actuating nose192rests when the securing lever172is located in its securing position.

The actuating cam190comprises a lifting surface196which extends from the first bearing surface194, slopes up from the first bearing surface194to a second bearing surface198and is capable, by acting on the actuating nose192, of moving the securing lever172in the direction of a disengaged position.

For this purpose, as is illustrated inFIG. 19, the securing lever172is pivoted about the axis176such that, as is illustrated inFIG. 24, the securing portion184is moved out of the through-passage108in the carrying plate26and no longer obstructs rotation of the actuating body52by the step186.

This disengaged position is achieved when the actuating nose192has been raised, by the lifting surface196, to the second bearing surface198and rests on the latter, as is illustrated, for example, inFIGS. 19,21and24.

The actuating cam190of the rotary drive element152co-ordinates the rotation of the rotary drive element152and the rotary movement of the actuating body52which is initiated by the rotary drive element, as is described hereinbelow.

As is illustrated inFIG. 17, the two carry-along devices164and166enter into recesses204and206provided for this purpose in the rotary drive element152, the recesses204and206being bounded by carry-along elements214and216, which, in the exemplary embodiment illustrated, are formed as termination walls of the recesses204and206. In a starting position of the rotary drive element152, which is illustrated inFIGS. 15 to 18, these carry-along elements214and216are spaced apart from the carry-along devices164and166.

In this starting position of the rotary drive element152, the actuating nose192, on account of the torsion spring188, rests on the first bearing surface194, so that the securing lever172is thus located in its securing position and uses the securing portion184to block rotary movement of the actuating body52from its active position into its inactive position.

The spacing of the carry-along elements214and216from the carry-along devices164and166, respectively, thus allows the rotary drive element152to rotate about the pivot axis22through a free-travel angle, in a free-travel state, without the actuating body52being carried along.

The free-travel angle of the rotation of the rotary drive element152here corresponds to the angle over which the lifting surface196extends on the actuating cam190, so that the rotary drive element152can be rotated with the actuating cam190, without the actuating body52being carried along, to the extent where the securing lever172, by the action of the lifting surface196on the actuating nose192, has been pivoted into its disengaged position, in which the securing portion184no longer blocks the rotary movement of the actuating body52.

This intermediate position of the rotary drive element152is illustrated inFIGS. 19 and 20, it being possible to see, in the intermediate position, that the carry-along elements214,216engage against the carry-along devices164and166, respectively.

Further rotation of the rotary drive element152thus results in the actuating body52being rotated along in a carry-along state of the actuating arrangement150, it being the case that, with the rotary movement of the rotary drive element152into the actuating position, which is illustrated inFIGS. 21 to 23, the actuating body52rotates in the direction64such that the rotation-blocking bodies54can pass into their release position and penetrate into the retraction receiving spaces62in the process.

At the same time, the actuating nose192, as it moves into the actuating position, slides on the second bearing surface198, which holds the securing lever172in the disengaged position, so that—as has already been described—it is possible for the actuating body52to be rotated into the inactive position without being obstructed by the securing portion184of the securing lever172.

For this purpose, continuous, for example, manual action on the pull cable156is necessary since the actuating body52is already subjected to the action of the torsion spring102.

Moreover, however, it is also the case that the rotary drive element152is subjected to the action of a torsion spring222such that, on account of the torsion spring222, the rotary drive element152always tends to return into its starting position.

The torsion spring222here is supported by one leg on the rotary drive element152and wraps around a torsion-spring mount224of the rotary drive element152and, in addition, has a leg226which is supported on a supporting finger228of a retaining part, which is designated as a whole by230and, for its part, is fixedly connected to the carrying plate26, the retaining part230also having a flange232, which retains the bearing journal174, and a flange234, on which the cable pull158is supported.

In order, moreover, for it to be possible to sense the positions of the securing lever172, it is also the case that a sensor236is mounted on the retaining part230, this sensor sensing the positions of the bracket portion182of the securing lever172and, in particular, detecting whether the securing lever172is located in its securing position or has moved out of the same.

This results in the following overall function of the trailer coupling according to the invention.

If the trailer coupling according to the invention is either in the operating position A or the rest position R, then, without the actuating arrangement150being subjected to any, for example, manual action, the rotary drive element152is in its starting position, so that the rotation-blocking device50also blocks rotation of the pivot-bearing body14about the pivot axis22in a play-free manner.

This takes place in that the actuating body52—as has already been described—on account of the action of the torsion spring102, is located in its active position and the rotation-blocking bodies54in their blocking position, activated by force, engage in the receiving spaces58or60.

Furthermore, with the rotary drive element152located in the starting position, the rotation-prevention means170is also located in its securing position since the securing lever172, on account of the action of the spring188, rests, by way of the actuating nose192, on the first bearing surface194of the actuating cam190and thus blocks rotation of the actuating body52in so far as the latter—even if the torsion spring102were to fail—cannot at any time rotate into the inactive position and, consequently, to the extent where the rotation-blocking bodies54pass into their release position. Rather, the actuating body52is blocked against rotary movement by the securing lever172, in particular the securing portion184of the same, such that the rotation-blocking bodies54always still rest on the pressure-exerting surfaces66of the actuating body52and are thus still retained, by the same, in a blocking position, in which the rotation-blocking bodies54engage either in the receiving spaces58or in the receiving spaces60and thus block rotary movement of the pivot-bearing body14, even if this blocking is no longer play-free.

If the actuating arrangement150is then subjected to action, for example via the pull cable156, then, in the first instance, the rotary drive element152is rotated in the free-travel state, which, without the actuating body52being rotated, results in the rotation-prevention means170passing from its securing position into its disengaged position and thus in it no longer being possible for the securing lever172to block rotary movement of the actuating body52from the active position into the inactive position. Once the intermediate position of the rotary drive element152has been reached, the latter also carries along on account of the carry-along state, via the carry-along devices164,166, the actuating body52in a further rotary movement, and thus moves the actuating body into the inactive position, the rotation-prevention means170simultaneously being retained in the disengaged position, namely in that the securing lever172remains in its disengaged position on account of the actuating nose192resting on the second bearing surface198.

If the action on the actuating arrangement150is done away with, for example as a result of the pull cable156being released, then, under the action of the torsion spring222and of the torsion spring102, the rotary drive element152and, together with it, the actuating body52, rotate back, namely to the extent where the actuating body52has reached its active position and the rotation-blocking bodies54, once again in their blocking position, engage in one of the receiving spaces58or60. Furthermore, the rotary drive element152then rotates back further, under the action of the torsion spring222, into the starting position, so that the rotation-prevention means170, once again, passes into its securing position and secures the actuating body52against rotation such that it passes into the inactive position.

In the case of a second exemplary embodiment of a trailer coupling according to the invention, this exemplary embodiment being illustrated inFIG. 25, the first end12of the ball neck is connected to a pivot-bearing body14′ which is located in the interior of the guide body40and is guided therein such that it can be rotated about the pivot axis22, in which case, for example, a cylindrical outer surface49of the pivot-bearing body14′ and a cylindrical inner lateral surface47of the guide sleeve44form the rotatable guide of the pivot-bearing body14′.

Furthermore the pivot-bearing body14′ is provided with the receiving spaces58a′,58b′ and58c′ for the rotation-blocking bodies54a,54band54c, into which the rotation-blocking bodies54a,54band54cproject in their blocking position and, in the process, bring about blocking of the pivot-bearing body14′ in the same way as has been described in conjunction with the first exemplary embodiment.

In the case of this exemplary embodiment, furthermore, the actuating body52′ is disposed such that it enclosed the guide sleeve44over its outer lateral surface46and has the retraction receiving spaces62a′,62b′ and62c′ with pressure-exerting surfaces66a′,66b′ and66c′ following the latter, so that, by virtue of the actuating body52′ being rotated in the direction of rotation72, the rotation-blocking bodies54a,54band54ccan be moved into their blocking position and, in the process, are subjected to the action of the pressure-exerting surfaces66a′,66b′ and66c′, whereas, in the case of the actuating body52′ being rotated counter to the direction of rotation72, the rotation-blocking bodies54a,54band54ccan be transferred into their release position, when they can penetrate into the retraction receiving spaces62a′,62b′ and62c′.

Otherwise, the second exemplary embodiment of the trailer coupling according to the invention functions in a manner analogous to the first exemplary embodiment, so that, in respect of the basic functions, reference can be made in full to what has been said for the first exemplary embodiment.

The second exemplary embodiment has the advantage that, for example, the actuation of the actuating body52′ can thus be simplified since this actuating body is easily accessible from its outer circumferential side.

In the case of a third exemplary embodiment of a trailer coupling according to the invention, represented inFIGS. 26 and 27, all those parts which are identical with those of the preceding exemplary embodiments are provided with the same reference signs, so that in respect of explanation of these, reference is made in full to the statements concerning the preceding exemplary embodiments.

In contrast to the first exemplary embodiment, in the case of the third exemplary embodiment, the actuating body52″ is not rotatable about the pivot axis22, but is arranged to be displaceable in the guide body40, preferably in the guide sleeve44, in its direction of actuation64″, substantially parallel to the pivot axis22.

For this reason, the retraction space62″ for each of the rotation-blocking bodies54is for example a cylindrical surface with respect to the pivot axis22and this is adjoined by a surface which widens conically in a radial direction with respect to the pivot axis22in order to form the pressure-exerting surface66″.

The pressure-exerting surfaces66″ are thus effective by displacing the actuating bodies52″ in the direction of the carrying plate26and press, in a manner analogous to the first exemplary embodiment, the rotation-blocking bodies54radially outwards and into the receiving spaces58or60, so that locking of the pivot-bearing body14is effected in a manner corresponding to the same mechanism as in the case of the first exemplary embodiment.

In similar manner, it is achieved by displacement of the actuating body52″ in the direction of actuation64but away from the carrying plate26, that the rotation-blocking bodies54interact with the retraction receiving space62and are no longer acted on by the pressure-exerting surfaces66, so that the rotation-blocking bodies54are able to enter into the guide sleeve of the guide body40so far that they no longer project radially above this and thus no longer engage in the receiving space58or60, so that the pivot-bearing body14is freely rotatable about the pivot axis22.

In the case of the third exemplary embodiment, the displacement of the actuating body52″ in the direction of actuation64″ is effected by any kind of linear drive.