Patent Publication Number: US-2021171100-A1

Title: Sensor system for a utility vehicle and fifth-wheel coupling system, utility vehicle comprising said sensor system, and method for same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National Phase Application under 35 U.S.C. § 371 of International Application No. PCT/EP2019/064275, filed on Jun. 3, 2019, and claims benefit to German Patent Application No. DE 10 2018 114 851.8, filed on Jun. 20, 2018. The International Application was published in German on Dec. 26, 2019 as WO 2019/243025 A1 under PCT Article 21(2). 
    
    
     FIELD 
     The invention relates to the field of utility vehicles and, in particular, to determining an articulation angle between a utility vehicle and a vehicle trailer towed by the utility vehicle. 
     BACKGROUND 
     In the field of utility vehicles it is known to record measured values in order to determine an operating state or driving state of the utility vehicle itself or else of a vehicle trailer which is towed by the utility vehicle. The measured values relating to the current operating state or driving state can then be used in driving assistant systems or safety systems in order to assist or inform the vehicle driver, or to counteract unstable or unsafe states automatically when such states occur. 
     In addition to the direct determination of measured values with sensors it is also known to estimate variables or variable quantities indirectly using other measured values or known quantities or to model them by means of the latter. An example of this is the determination of an articulation angle between a utility vehicle and a vehicle trailer which is towed by the utility vehicle. Such an articulation angle is modeled, for example, taking into account the measured speed, measured yaw rates of the utility vehicle and fixed geometric parameters. The articulation angle which is determined in this way can be taken into account, for example, in safety systems of the vehicle such as, for example, an electronic stability control (ESP [Electronic Stability Program]). 
     The monitoring of an articulation angle preferably also serves to warn a vehicle driver if the vehicle trailer has jackknifed too much in comparison with the utility vehicle, for example during reverse travel through tight bends. As a result, for example, it is possible to avoid connecting cables or connecting lines from being torn off between the motor vehicle and the vehicle trailer if the vehicle driver reacts to the warning. 
     In addition, a determined articulation angle between a utility vehicle and a vehicle trailer can be used to permit partial autonomous driving of the utility vehicle to which a vehicle trailer is coupled, even in a direction of reverse travel. 
     Sensor arrangements or sensor systems are known from the prior art, in order also to permit a direct articulation angle measurement in comparison with absolute articulation angles which are determined indirectly by means of the modeling. 
     Such sensors can be implemented, for example, as optical sensors, wherein they have the disadvantage that as a result of soiling they do not supply measured values or to a certain extent supply incorrect measured values. Furthermore, sensors are known which are arranged on the utility vehicle and are in direct contact with the vehicle trailer, for example through a wheel. Therefore, by means of these sensors at least one relative movement of the vehicles with respect to one another can be measured. 
     However, the sensors just mentioned can frequently be used only in a specific measuring range of the articulation angle, since regions in which the articulation angle can be measured exclusively independently of other relative movement between the vehicle trailer and the utility vehicle are available only to a limited degree. 
     EP 0 471 286 B1 describes, for example, integrating a roller sensor into an opening of a fifth wheel of a fifth-wheel coupling. However, such a solution involves the problem that owing to the opening, stability of the fifth wheel has to be ensured through additional reinforcement. On the other hand, a trailer coupling which is present and which is configured, for example, as a fifth-wheel coupling cannot be retrofitted by means of this solution, since a stability-reducing opening for the sensor cannot be readily formed. 
     SUMMARY 
     In an embodiment, the present invention provides a sensor system for determining an angular change between a utility vehicle having a trailer coupling and a coupled vehicle trailer. The sensor system includes a sensor unit having a wheel mounted so as to be rotatable about an axis, and a rotary encoder connected to the wheel and configured to detect a change in position of the wheel. The sensor system further includes a mount having at least one first fixed part configured to connect the sensor system to the utility vehicle or a part thereof, and at least one movable part connected to the sensor unit and mounted so as to be movable on the fixed part. In addition, the sensor system includes a positioning mechanism at least configured to provide sprung bearing of the movable part in an operating position in such a way that the wheel of the sensor unit can be moved into contact with a vehicle trailer or a part of the vehicle trailer. The mount is adapted to arrange, at least in the operating position, the wheel of the sensor unit outside a support face of the trailer coupling, next to the support face, in such a way that in the operating position a contact face of the wheel is configured to be moved into a plane formed by the support face, into a region over which a baseplate of the vehicle trailer can move. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be described in even greater detail below based on the exemplary figures. The invention is not limited to the exemplary embodiments. All features described and/or illustrated herein can be used alone or combined in different combinations in embodiments of the invention. The features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the attached drawings which illustrate the following: 
         FIG. 1  shows a utility vehicle with a vehicle trailer; 
         FIG. 2  shows an articulated truck with a semi-trailer; 
         FIG. 3  shows a fifth-wheel coupling in a plan view; 
         FIG. 4  shows a fifth-wheel coupling in a view from below; 
         FIG. 5  shows a sensor system which is connected to the fifth-wheel coupling, in a view of the fifth-wheel coupling from below; 
         FIG. 6  shows a perspective view of a fifth-wheel coupling system; 
         FIG. 7  shows a view of the sensor system in a position of rest; 
         FIG. 8  shows a view of the sensor system in an operating position; 
         FIG. 9  shows steps of a method for attaching a sensor system to a fifth-wheel coupling; and 
         FIG. 10  shows steps of a method for coupling a vehicle trailer to a utility vehicle. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure describes a sensor system which counters problems of the prior art. In particular, a sensor system is described that can be retrofitted without reducing stability of a trailer coupling which is present. 
     For this purpose, a sensor system is provided for determining a change in angle between the utility vehicle and a vehicle trailer. The utility vehicle is, for example, a tractor and the vehicle trailer is, for example, a semi-trailer. The sensor system comprises a sensor unit, a mount and a positioning mechanism. 
     The sensor unit comprises a wheel which is mounted so as to be rotatable about an axis, and a rotary encoder which is connected to the wheel, in order to detect a change in position of the wheel. The term wheel is selected here in order to generally describe a rotational body which can rotate about an axis. Therefore, the term does not constitute a limitation of the geometric shape. The wheel also comprises, for example, a spherical body or the like which is mounted on a rotational axis. 
     The mount comprises at least one fixed part for mounting the system on the utility vehicle or a part of the utility vehicle, and at least one movable part which is connected to the sensor unit and is movably mounted on the fixed part. The movable part is preferably rotatably mounted on the fixed part. According to one alternative, the movable part is mounted in a linearly displaceable fashion on the fixed part. 
     The positioning mechanism is configured to mount the movable part at least in an operating position, preferably an operating position range. This mounting is embodied as a sprung mounting. The movable part is therefore spring-mounted so that the movable part is arranged in different positions within the operating position range by means of the positioning mechanism as a function of a force applied to the suspension mounting. In this case, the positioning mechanism serves to mount the movable part, at least in the operating position, in particular so that the wheel of the sensor unit which is connected to the movable part can be brought into contact with a vehicle trailer with a spring force. 
     The operating position denotes here in particular the position of the wheel so that the contact area which runs around the wheel rests in a plane with the support face or function linings of the support face. 
     In this context, the present disclosure makes use of the knowledge that usually a larger area is selected for a contact area of the vehicle trailer, that is to say a region of a contact plate of the vehicle trailer which is adapted to rest on a support face of a trailer coupling, than the support face itself. 
     This contact region of the contact trailer is generally embodied in a flat fashion and free of unevenness so that in this contact area the wheel of the sensor unit can advantageously detect here a relative movement between the utility vehicle and the vehicle trailer without disruption. The mount can therefore easily be attached subsequently to an existing trailer coupling or retrofitted, without additional stability measures or complex processing of the trailer coupling being necessary. 
     According to one embodiment, the mount is adapted, in particular if the movable part is in the operating position, to arrange the wheel of the sensor unit outside a support face of the trailer coupling but nearer to the support face, specifically preferably at a distance from the support face of less than 0.2 m or less than 0.1 m. The distance is preferably defined as the distance between a contour of the support face and a contact face of the wheel which runs around the wheel, in order to bring about contact with the vehicle trailer. 
     In accordance with one embodiment, the positioning mechanism is configured to transfer the movable part of the mount out of the operating position into a position of rest and/or to support it in the position of rest which is different from the operating position and is, in particular, outside the operating position range. In this context, the position of rest is selected such that the wheel of the sensor unit which is connected to the movable part can preferably be arranged spaced apart from the vehicle trailer. This makes it possible that during the coupling and uncoupling an approaching part or coupling part of the vehicle trailer or a part or coupling part of the vehicle trailer which is moving away applies to the wheel a force which has a traverse component with respect to the rotational axis and could bring about damage. 
     Therefore, for coupling and uncoupling the wheel trailer the wheel can preferably be transferred into the position of rest by means of the positioning mechanism so that the vehicle trailer can be coupled to or uncoupled from the utility vehicle without damage to the sensor system. 
     According to one embodiment, the mount is configured to be connected in the region or to a trailer coupling which is embodied as a fifth-wheel coupling which has a fifth wheel which has a securing region and in which a kingpin can be coupled. The mount is adapted here to secure the wheel of the sensor unit at least in the operating position range at a distance from the securing range which is less than the maximum distance of a contour of the support face from the securing region. 
     This always ensures that in the operating position range the wheel of the sensor unit is securely in contact with a contact face of the vehicle trailer for a fifth-wheel coupling independently to the articulation angle. Use is made of the fact here that the contact face of the vehicle trailer has, for the purpose of forming contact with the fifth-wheel coupling, which can also be referred to as a region of a baseplate, at least one diameter, so that the contact face is in all cases in contact with the entire support face at the widest region of the support face. Therefore, in narrower regions of the support face in which the wheel can be arranged according to this exemplary embodiment, part of the baseplate is always connected to the wheel even when there is a rotational movement, so that the relative movement of the vehicle trailer with respect to the utility vehicle can always be measured. 
     According to a further embodiment, the mount is adapted to be connected in the region of with a trailer coupling, embodied as a fifth-wheel coupling, of the utility vehicle, so that by means of the movable part the wheel of the sensor unit can be arranged, at least in the operating position, in front of the support face opposite a junction area of a guide, leading to a securing region, of the fifth-wheel coupling for a kingpin or in the region of the guide. In this context, the mount is in particular adapted in such a way that, at least in the operating position, the axis of the wheel runs radially with respect to the securing region. 
     In this context, use is made of the knowledge that the edge of the support face or the contour of the support face, of a fifth-wheel coupling on the front side of the fifth-wheel coupling which corresponds to the side which lies in front of the support face opposite a junction region, is at a shorter distance from the securing region than on the side regions. Since the contact faces of vehicle trailers are embodied at least so large that they are in total contact with the support face of a fifth-wheel coupling, accordingly on the front side of the fifth-wheel coupling which is made less solid in order to save material there is a region present by which basically the contact face of the vehicle trailer passes. An arrangement of the wheel of the sensor unit in this region therefore ensures that even if the contact face of a vehicle trailer is just equal to the maximum width of the support face of the fifth-wheel coupling, at any rate the front region of the fifth-wheel coupling is passed by the contact face of a vehicle trailer on the support face in front of the fifth-wheel coupling when there is a relatively large rotational movement, such that the rotational movement is reliably detected by the wheel. 
     According to a further embodiment, the fixed part of the mount is adapted to be fastened to bolts of a fifth-wheel coupling which serve to fasten friction linings. Accordingly, bolts which are present on the fifth-wheel coupling with which friction linings are fastened and which can be easily removed in order to exchange the friction linings are used in order additionally to fasten the fixed part of the mount. Instead of the direct use of bolts which are present, these bolts are alternatively replaced by long bolts. The mount is accordingly adapted to the existing position of these bolts so that without additional further components the sensor system can easily be fastened to a fifth-wheel coupling. According to one preferred embodiment, the bolts are reinforced or lengthened by means of sleeves, in order to reduce elasticity in the mount. 
     According to a further embodiment, the positioning mechanism has a connecting part. The connecting part is adapted to be connected with a closing mechanism, in particular an activation lever for the closing mechanism, of the trailer coupling of the vehicle. The connecting part is therefore preferably adapted in such a way that by activating the activation lever of the closing mechanism the movable part can be transferred between an operating position and the position of rest. 
     It is ensured here that only if a vehicle trailer is fixedly coupled to a utility vehicle by activating the closing mechanism, automatically, specifically by means of the connecting part and the positioning mechanism, the movable part is transferred into an operating position. The sensor unit, and in particular the wheel of the sensor unit, previously remain in their position of rest, so that no contact is made between the vehicle trailer and the wheel, and thus no forces with a transverse component with respect to the rotational axis of the wheel which can possibly bring about damage to the sensor unit are applied to the wheel of the sensor unit. 
     According to a further embodiment, the positioning mechanism comprises an adjustment device. This adjustment device is preferably a component of the connecting part. The adjustment device serves to vary the operating position and/or the position of rest and/or the spring force during the spring mounting of the movable part. Therefore, a connecting part which is connected to a closing mechanism of a trailer coupling of a utility vehicle can be adapted to the configuration of the closing mechanism, in particular of the activation lever, and to the lever travel, so that the sensor system can be adapted for a multiplicity of different trailer couplings solely by adjustment with the adjustment device, without structural changes. 
     According to a further embodiment, the rotary encoder is an incremental rotary encoder, in particular an incremental encoder, or an absolute rotary encoder. Furthermore or in addition the rotary encoder is configured to output a pulse-width-modulated signal (PWM signal) with detection of the direction of propagation, in particular an AB signal or a data signal, in particular a bus signal, preferably a CAN bus signal, as a function of a change in position. 
     Furthermore, the present disclosure relates to a fifth-wheel coupling system with a fifth-wheel coupling and a sensor system according to one of the abovementioned embodiments. Here, the fixed part of the mount of the sensor system is connected to the fifth-wheel coupling. Furthermore, by means of the mount at least in the operating position the wheel of the sensor unit is arranged outside a support face of the fifth-wheel coupling near to the support face. In addition, the wheel is arranged at least in the operating position with the mount outside the support face of the trailer coupling next to the support face. The wheel is preferably arranged in such a way that in the operating position the contact face of the wheel lies in a plane formed by the support face, in a region over which a baseplate of the vehicle trailer can move. 
     According to one embodiment of the fifth-wheel coupling system, the distance between the support face and the wheel is less than 0.2 m or less than 0.1 m. 
     According to one embodiment, the mount is connected in the region of or to the fifth-wheel coupling. The fifth-wheel coupling has a securing region in which a kingpin can be coupled. Furthermore, at least in the operating position, the wheel of the sensor unit is arranged by the mount at a distance from the securing region which is less than the maximum distance of a contour of the support face or fifth-wheel coupling from the securing region. 
     According to a further embodiment, the mount is connected in the region of or to the fifth-wheel coupling so that the wheel is arranged by the movable part of the sensor unit, at least in the operating position, in front of the support face opposite the junction region of the guide, leading to the securing region, of the fifth-wheel coupling for the kingpin or in the region of the guide. The axis of the wheel runs here, as is furthermore also the case, in particular, in other embodiments, in the operating position radially with respect to the securing region or with respect to the center, in particular with respect to an axis running through the center, of the securing region. 
     According to a further embodiment, the fifth-wheel coupling has a closing mechanism which is configured to couple a kingpin of a vehicle trailer to the fifth-wheel coupling or to release it. The closing mechanism is connected to the connecting part of the positioning arrangement of the sensor system. 
     According to a further embodiment, the fifth-wheel coupling has bolts for fastening friction linings. The fixed part of the mount is fastened to the bolt at the fifth-wheel coupling. 
     Furthermore, the present disclosure provides a utility vehicle having a fifth-wheel coupling system according to one of the abovementioned embodiments. 
     Furthermore, the present disclosure provides a method for attaching a sensor system according to one of the abovementioned embodiments to a fifth-wheel coupling for a utility vehicle. For this purpose, the fixed part of the mount of the sensor system is connected to the bolts for fastening friction linings of the fifth-wheel coupling. Furthermore, a connecting part of the positioning arrangement is connected to a closing mechanism of the fifth-wheel coupling. 
     According to one embodiment of the method for arranging the sensor system, an operating position and/or a position of rest and/or a spring force of the spring are/is set during the spring mounting in the operating position of a movable part of the mount of the sensor system with an adjustment device of the sensor system. 
     Furthermore, the present disclosure relates to a method for coupling a semi-trailer to an articulated truck. In this context, a kingpin of a semi-trailer is firstly introduced into a fifth-wheel coupling of the articulated truck. Then, the fifth-wheel coupling is locked by means of a closing mechanism, and according to one of the abovementioned embodiments, the movable part of a mount of a sensor system is transferred from a position of rest into an operating position. 
     According to one embodiment of the method for coupling, the transfer of the movable part is carried out by the locking process. 
       FIG. 1  shows a utility vehicle  10  which is connected to a vehicle trailer  12  via a trailer coupling  14 . The utility vehicle  10  has a drive (not illustrated) with which the utility vehicle  10  can be driven, and tows the vehicle trailer  12 , which is coupled to it in the case of forward travel or pushes it in the case of reverse travel. 
       FIG. 2  also shows a utility vehicle  10  which, however, is embodied here as a tractor  16 . The tractor  16  also tows a vehicle trailer  12  which is embodied here, however, as a semi-trailer  18 . The semi-trailer  18  is also coupled to the tractor  16  via a trailer coupling  14 , which is embodied in  FIG. 2 , however, as a fifth-wheel coupling  20 . The fifth-wheel coupling  20  is arranged on the tractor  16  and secures a kingpin  21  of the semi-trailer  18 , so that the tractor  16  can tow the semi-trailer  18  in the case of forward travel and can push it in the case of reverse travel by means of the fifth-wheel coupling  20  and the kingpin  21  which is coupled therein.  FIG. 2  shows the tractor  16  and the semi-trailer  18  during travel in a left-hand bend. This results, for example, in an angular change  17  between the tractor  16  and the semi-trailer  18 . The angular change  17  is referred to as an articulation angle or change in articulation angle and corresponds to the angle between the longitudinal axes of the vehicles, that is to say the vehicle longitudinal axes, here therefore the longitudinal axis  15  of the tractor  16  and the longitudinal axis  19  of the semi-trailer  18 . 
       FIG. 3  shows a plan view of a fifth-wheel coupling  20 . The fifth-wheel coupling has a fifth wheel  22  which has a support face  24  on its upper side. The support face  24  comprises a contour  26  within which the support face  24  is preferably essentially embodied in a flat fashion. The support face  24  has friction linings  27  which are fastened with bolts  28  on the fifth wheel  22  and can be exchanged therewith. In the center of the fifth wheel  22  there is a securing region  30  provided in order to receive the kingpin  21  and couple it in the securing region  30 . The coupling or securing is carried out by means of a locking bar  32  of a closing mechanism  34 . 
     Accordingly, the kingpin  21  can be introduced into the securing region  30  in a longitudinal direction  36  via a junction region  38  and a guide  40  which adjoins the junction region  38 , while the locking bar  32  is folded away. The kingpin  21  then presses on a plate  42  so that the locking bar  32  can rotate into the illustrated position. The locking bar  32  is then locked by means of an activation lever  44  via the closing mechanism  34 . In order to release the kingpin  21 , the activation lever  44  is in turn transferred into another position so that the locking bar  32  can fold away and the kingpin  21  can be decoupled again from the securing region  30  via the guide  40  and the junction region  38 . 
     Furthermore,  FIG. 3  shows a region  46  of a baseplate  48  which is embodied in an essentially flat fashion at the semi-trailer  18 , in order to rest on the support face  24 , specifically, in particular, the friction linings  27 . The baseplate  48  has at least the region  46  with an essentially flat design, which has a radius  50  which corresponds to at least the maximum distance  52  between the center  54  of the securing region  30  with respect to the contour  26  of the support face  24 . This ensures that during cornering at large articulation angles of the semi-trailer  18  the entire support face  24  or the friction linings  27  are always in contact with the baseplate  48 . The baseplate  48  is part  49  of the controller  12 . The region  46  of the baseplate  48  therefore corresponds to a region  55  of the fifth-wheel coupling  20  over which the vehicle trailer  12  always passes during cornering. 
       FIG. 4  shows the fifth-wheel coupling  20  from the underside, wherein here the closing mechanism  34  is illustrated in more detail. Accordingly it is apparent that the activation lever  44  can move in the transverse direction  56  of the fifth wheel  22 , in order to release or fix the locking bar  32  by means of various further levers. Likewise, the bolts  28 , which are each secured with a nut  58  and secure the friction linings  27  on the support face  24 , are illustrated in  FIG. 4 . 
     According to one exemplary embodiment, the bolts  28  in the front region  60  of the fifth-wheel coupling  20  serve as fastening points  62  for fastening a sensor system which is explained below. In addition, the activation lever  44  has an opening, in particular a drilled hole  64 , which also serves to connect the activation lever  44  as a fastening point  66  for the connection of the sensor system which will be explained later. 
       FIG. 5  then shows the sensor system  70 , which is fastened to a fifth-wheel coupling  20 , specifically in particular the bolt  28  of the fifth-wheel coupling  20  for fastening the friction linings  27  and to the activation lever  44 . 
     The sensor system  70  comprises for this purpose a mount  72  which has a fixed part  74  and a movable part  76 . The fixed part  74  comprises essentially a web  78  which is connected to both bolts  28 , which serve as fastening points  62  as illustrated in  FIG. 4 . 
     The web  78  comprises a bearing  80 , on which the movable part  76  is rotatably mounted. The movable part  76  is connected on one side to the bearing  80  and on the other side a sensor unit  82  is fixedly arranged. The sensor unit  82  comprises a wheel  84  which is connected to a rotary encoder  88  via an axle  86 . In this context, the axle  86  leads through an opening with a bearing in a securing plate  85 . The securing plate  85  can be considered to be a component of the sensor unit  82  or of the movable part  76 . The wheel  84  has a circumferential contact face  85  which can be placed in contact with the vehicle trailer  12 . Furthermore, protection  90  for the sensor system  70  is illustrated, which protection  90  is optionally provided and protects against undesired shocks to the sensor system  70 . 
     Furthermore, the sensor system  70  has a positioning mechanism  92 . The positioning mechanism  92  comprises a connecting part  94  which is connected to the fastening point  66  (illustrated in  FIG. 4 ) of the activation lever  44 . The connecting part  14  is connected to a rod  96  which leads through an opening  98  in a lever  100  of the movable part  76 . The opening  98  has a larger diameter than the rod. 
     Furthermore, a region of the rod  96  is provided with a thread  102 , onto which a nut  104  is screwed. A spring  106  is connected to the nut  104  and is also connected to the lever  100  of the movable part  76 . The spring  106  is preferably a tension spring. A further spring  108  is arranged on the bar  96 . The further spring  108  is preferably a compression spring. In addition, a disk  110  which is freely movable on the bar is arranged opposite the spring  108  with respect to the nut  104 . The nut  104  and the thread  102  are parts of an adjusting device  103 . 
     Here,  FIG. 5  illustrates the movable part  76  in a position of rest in which the sensor unit  82  and the movable part  76  lie below a plane, formed by the support face  24 , opposite an operating position which is shown later. This position has been assumed by the activation lever  44  being pulled downward, when viewed from the center of the fifth-wheel coupling  20 . As a result, the spring  106  entrains the lever  100 , so that the movable part  76  is rotated about the bearing  80 , into the position of rest. 
     In the case shown later in which the sensor unit  82  is in an operating position, the activation lever  44  is pressed inward to the center, that is to say in the direction  112 , so that the rod  96  of the positioning mechanism  92  is guided through the opening  98  via the connecting part  94 , until the disk  110  is pressed against the edge of the opening  98 , onto the lever  100  by the spring  108 . Through further movement of the activation lever  44  in the direction  112 , a force is then applied to the lever  100 , which then rotates the movable part  76  with the bearing  80  about the fixed part  74 . Therefore, the sensor unit  82  is as a result moved in such a way that the wheel  84  lies above a plane formed by the support face  24  of the fifth-wheel coupling  20 , and the wheel  84  can enter into contact with the baseplate  48  of a semitrailer  18 . In this context, the movable part  76  and the sensor unit  82  are then located in the operating position with spring loading by the spring  108 . 
       FIG. 6  shows a perspective view of a fifth-wheel coupling system  114  which comprises the fifth-wheel coupling  20  and the sensor system  70 . A particularly advantageous insulation position of the sensor system  70  in front of the fifth wheel  22  of the fifth-wheel coupling  20 , that is to say on a front side  118  of the fifth-wheel coupling  20 , can be seen. Accordingly, the sensor system  70  is located outside the support face  24  of the fifth-wheel coupling  20  and is arranged by the mount near to the support face  24  at a distance  116  from the support face  24  of less than 10 cm. The sensor system  70  is located here in a position of rest so that the wheel  84  lies lower than a plane  115  which is formed by the support face  24 . In front of the fifth-wheel coupling  20  therefore means arranged on the front side  118  of the fifth-wheel coupling  20  which is defined as the side of the fifth-wheel coupling  20  which is arranged opposite the junction region  38  for the kingpin  21 . 
       FIG. 7  shows a further view of the sensor system  70  which is in a position of rest  120 . Here, in order to clarify the position of rest  120  the baseplate  48  of a semi-trailer  18  is also illustrated, said baseplate  48  resting on the fifth wheel  22 , specifically on the support face  24  of the fifth wheel  22  with the friction linings  27 . The sensor unit  70  is not in contact with the baseplate  48  but rather spaced apart therefrom. 
     In contrast,  FIG. 8  illustrates an operating position  122  in which the wheel  84  is in contact with the baseplate  48  of the semi-trailer  18 . A moving baseplate  48  which rests on the support face  24  accordingly causes the wheel  84  to rotate, which can then be detected by means of the rotary encoder  88 . 
       FIG. 9  shows by way of example the steps of a method for arranging a sensor system  70 . In the first step  130 , a fixed part  74  of a mount  72  of the sensor system  70  is connected to bolts  28  of a fifth-wheel coupling  20 . In the step  132 , a connecting part  94  of a positioning mechanism  92  of the sensor system  70  is connected to a fastening point  66  of an activation lever  44  of a closing mechanism  34  of a fifth-wheel coupling  20 . In step  134 , a position of rest  120  and an operating position  122  are set by an adjustment mechanism  103 , specifically by adjusting a nut  104  on a thread  102 . 
       FIG. 10  shows the steps of a method for coupling a semi-trailer  18  with a tractor  16 . In the step  140 , a kingpin  21  of a semi-trailer  18  is moved into a securing region  30  of a fifth-wheel coupling  20  via a junction region  38  and a guide  40 . In the securing region  30 , the kingpin  21  is then locked  142  by means of a closing mechanism  34 . In the step  144 , an activation lever  44  for activating the closing mechanism  34 , specifically for locking the locking bar  32 , of the closing mechanism  34  is repositioned in order as a result to simultaneously transfer the sensor unit  82  and the movable part  76  of the sensor system  70  in to an operating position  122 . 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. It will be understood that changes and modifications may be made by those of ordinary skill within the scope of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below. 
     The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C. 
     LIST OF REFERENCE NUMERALS 
       10  Utility vehicle 
       12  Vehicle trailer 
       14  Trailer coupling 
       15  Longitudinal axis 
       16  Tractor 
       17  Angular change 
       18  Semi-trailer 
       19  Longitudinal axis 
       20  Fifth-wheel coupling 
       21  Kingpin 
       22  Fifth wheel 
       24  Support face 
       26  Contour 
       27  Friction linings 
       28  Bolt 
       30  Securing region 
       32  Locking bar 
       34  Closing mechanism 
       36  Longitudinal direction 
       38  Junction region 
       40  Guide 
       42  Plate 
       44  Activation lever 
       46  Region 
       48  Baseplate 
       50  Radius 
       49  Part of vehicle trailer 
       52  Maximum distance 
       54  Center 
       55  Region 
       56  Transverse direction 
       58  Nut 
       60  Front region 
       62  Fastening points 
       64  Drilled hole 
       66  Fastening point 
       70  Sensor system 
       72  Mount 
       74  Fixed part 
       76  Movable part 
       78  Web 
       80  Bearing 
       82  Sensor unit 
       84  Wheel 
       85  Contact face of wheel 
       86  Axis 
       87  Securing plate 
       88  Rotary encoder 
       90  Protection 
       92  Positioning mechanism 
       94  Connecting part 
       96  Rod 
       98  Opening 
       100  Lever 
       102  Thread 
       103  Adjustment device 
       104  Nut 
       106  Spring 
       108  Further spring 
       110  Disk 
       112  Direction 
       114  Fifth-wheel coupling system 
       115  Plane 
       116  Distance 
       118  Front side 
       120  Position of rest 
       122  Operating position 
       130 - 134  Steps of method for arranging a sensor system 
       140 - 144  Steps of method for coupling a semi-trailer