Positioning unit for a charging station and method for contacting

Abstract

Positioning unit (10) for a charging station of an electrically powered vehicle, in particular an electric bus or the like, wherein the positioning unit is designed to be arranged above a vehicle, wherein an electrical charging contact of the charging station is movable relative to a contact surface of the vehicle and can be made to contact with it by means of the positioning unit, wherein the positioning unit has an articulated arm device (11) and a drive device (12) for driving the articulated arm device, wherein the drive device has an adjusting drive (29) for generating an adjusting force acting on the articulated arm device and a spring device (31) that mechanically interacts with the adjusting drive, wherein the spring device comprises at least one retractable spring (34) for generating a restoring force on the articulated arm device, wherein the restoring force is greater than a weight force of the articulated arm device acting opposite to the retractable spring.characterized in that the spring device comprises at least one contact spring (32), wherein the adjusting drive and the contact spring are coupled to each other in a mechanical series connection (53) such that a contact force can be formed on the contact surface by the adjusting drive and the contact spring.

Description

[0001] The invention relates to a positioning unit for a charging station of an electrically powered vehicle and a method for forming an electrically conductive connection between the vehicle, in particular an electric bus or the like, and the charging station, wherein the positioning unit is designed to be arranged above a vehicle, wherein an electrical charging contact of the charging station is movable relative to a contact surface of the vehicle and can be contacted with it by means of the positioning unit, wherein the positioning unit has an articulated arm device and a drive device for driving the articulated arm device, wherein the drive device has an adjusting drive for forming an adjusting force acting on the articulated arm device and a spring device that mechanically interacts with the adjusting drive.

[0002] Such positioning units and methods are known from the prior art and are regularly used in electrically powered vehicles that travel between stops. These can be electric buses, but also, in principle, other vehicles such as trains or trams that are not permanently electrically connected to an overhead line or similar structure. In these vehicles, an electrical energy storage device is recharged at a charging station when the journey is interrupted at a stop. The vehicle is electrically connected to the charging station at the stop, whereby the energy storage device is charged at least sufficiently for the vehicle to reach the next stop with a charging station.To establish an electrical connection between the vehicle and the charging station, a positioning unit is used, which can be mounted on the vehicle's roof and connects a charging contact of the vehicle to a contact surface of the charging station located above the vehicle. It is also known to use positioning units that are mounted or positioned above the vehicle at the relevant charging station stop. A charging contact of the charging station is then moved towards a contact surface on the vehicle's roof, thus establishing an electrical connection. With this method of vehicle contacting, all charging stations along a route must be equipped with a corresponding positioning unit, which is why the positioning unit must be particularly cost-effective, reliable, and low-maintenance.

[0003] A key aspect of integrating a charging station and the vehicle's contact surface is that the charging contact is pressed onto the contact surface with a defined contact force to establish a secure electrical connection. A positioning unit for generating a defined contact force is known from DE 43 34 716 A1, wherein this positioning unit serves to draw current from an overhead line and the contact force is measured and controlled by the positioning unit.

[0004] A positioning unit for arrangement above a vehicle is known from DE 20 2014 007 218 U1, wherein the positioning unit comprises an articulated arm device and a drive device. The drive device has an adjustment drive and a spring assembly, which serve to move the articulated arm device relative to a contact surface of the vehicle. In particular, an upward movement of the articulated arm device requires an adjustment force from the adjustment drive.

[0005] The generic WO 2015 / 022 008 A1 discloses a positioning unit for a contact device for charging electrically powered vehicles. Two embodiments are described: a positioning unit for mounting on the roof of a vehicle and a positioning unit for mounting on a charging station above the roof of a vehicle. Regarding the embodiment mounted on the charging station, it is stated that a spring preload causes the unit to move into a retracted position if a power supply or drive fails.

[0006] A disadvantage of known positioning units is that they must be designed or arranged for a defined contact height, i.e., a specific distance between the positioning unit in its insertion position (for securing the charging contact) and the contact position for power transmission to the vehicle. This means that the relative distance between the contact position and the insertion position is not variable and must be regularly adjusted or modified through design changes, otherwise the necessary or desired contact force cannot be applied to the contact surface. This is not significant as long as vehicles of the same height approach the respective stops or charging stations. However, if vehicle types and thus vehicle heights change, the relative distance between the insertion position and the contact position can fluctuate considerably due to differing heights of the vehicles' contact surfaces above the roadway.The same applies to varying vehicle loads. Furthermore, buses, in particular, can be lowered at bus stops to facilitate access for people with disabilities, for example. This lowering of the bus causes a change in the height of the contact surface relative to the roadway and, if the lowering occurs only on one side of the bus, causes the bus to tilt around its longitudinal axis. Consequently, the contact surface on the roof of the bus moves horizontally and vertically with the bus's tilting motion relative to the charging contact. Therefore, it is virtually impossible to establish the contact force required for a secure electrical connection between the charging contact of the charging station and the contact surface of the vehicle in the aforementioned applications.However, adjusting a contact force through the use of sensors and a control system is complex and maintenance-intensive, which would significantly increase the manufacturing and operating costs of a positioning unit.

[0007] It is therefore an object of the invention to propose a positioning unit and a method for forming an electrically conductive connection between a vehicle and a charging station which enables safe contacting of the vehicle at low acquisition and operating costs.

[0008] This problem is solved by a positioning unit having the features of claim 1, a charging station having the features of claim 15 and a method having the features of claim 16.

[0009] The positioning unit according to the invention for a charging station of an electrically powered vehicle, in particular an electric bus or the like, is designed to be arranged above a vehicle, wherein an electrical charging contact of the charging station is movable relative to a contact surface of the vehicle and can be made contact with it by means of the positioning unit, wherein the positioning unit has an articulated arm device and a drive device for driving the articulated arm device, wherein the drive device has an adjusting drive for generating an adjusting force acting on the articulated arm device and a spring device mechanically cooperating with the adjusting drive, wherein the spring device comprises at least one rebound spring for generating a restoring force on the articulated arm device, wherein the restoring force is greater than a weight force of the articulated arm device acting opposite to the rebound spring.wherein the spring device comprises at least one contact spring, wherein the adjusting drive and the contact spring are coupled to each other in a mechanical series connection, such that a contact force can be generated on the contact surface by the adjusting drive and the contact spring.

[0010] The positioning unit is therefore a component of a stationary charging station for an electric vehicle and serves to move the charging contact of the charging station onto a contact surface of the vehicle, preferably located on the vehicle roof, and to establish electrical contact with it. This makes it possible to supply the vehicle with electrical energy during a break in driving at the charging station and to store this energy in the vehicle. The movement of the charging contact to and from the contact surface is carried out by the articulated arm and the drive unit of the positioning unit. The charging contact is located at a lower end of the articulated arm. The drive unit serves to move the charging contact, and thus the articulated arm, from an upper retraction position for storing the charging contact to a lower contact position for power transmission.The contact surface is moved to make contact with the charging contact. In the contact position, a defined contact force is applied to the contact surface by the positioning unit.

[0011] The actuator of the drive device exerts an adjusting force on the articulated arm device. The actuator interacts mechanically with the spring assembly, so that the adjusting force alone can cause movement of the articulated arm device. The contact spring is coupled to the actuator in a mechanical series connection, meaning that they are coupled directly or indirectly. The actuator can be connected directly to the contact spring or via an interposed mechanical component, such as a lever. In this way, the actuator and the contact spring can jointly generate a contact force, which is then transmitted to the charging contact on the contact surface.The mechanical series connection of the adjusting drive and contact spring makes it possible to move the articulated arm device using the adjusting force of the adjusting drive and to further increase this adjusting force when the contact surface makes contact with the charging contact. This increased adjusting force is then stored by the contact spring connected to the adjusting drive and transferred as a contact force to the articulated arm device or the contact surface. Thus, the increase in adjusting force does not result in further movement of the articulated arm device, but rather in the generation and increase of the contact force on the contact surface. This makes it possible to generate a substantially constant contact force on the contact surface, regardless of the height of the contact surface above a road surface or the relative distance between the contact surface and the charging contact in a retracted position of the charging contact.

[0012] According to the invention, the spring assembly comprises at least one retractable spring for generating a restoring force on the articulated arm device, wherein the restoring force is greater than the weight force of the articulated arm device acting in the opposite direction to the retractable spring. After contact of the contact surface with the charging contact, the charging contact can be easily returned to a retracted position at the positioning unit. A weight force of the articulated arm device and the charging contact arranged on the articulated arm device can cause the articulated arm device to move from the retracted position to the contact position, which is not desirable. The retractable spring can prevent this by generating a restoring force on the articulated arm device. The restoring force opposes the weight force and is preferably slightly greater than it to prevent the articulated arm device from sinking or...To prevent the charging contact from extending when the articulated arm device is not subjected to any further force.

[0013] In one embodiment of the positioning unit, the contact spring can be coupled to the adjustment drive via a floating bearing, whereby the contact spring or the adjustment drive can be mounted on a fixed bearing. By definition, the fixed bearing is then not movable relative to other fixed bearings of the articulated arm assembly and the drive assembly. The floating bearing, which then directly connects the contact spring to the adjustment drive, can comprise one or more bearing shafts. If the contact spring is mounted on the fixed bearing, the adjustment drive can be connected or coupled to the articulated arm assembly, and if the adjustment drive is mounted on the fixed bearing, the contact spring can be connected to the articulated arm assembly. In principle, it is irrelevant whether the contact spring and the adjustment drive are translationally or rotationally acting springs or adjustment drives.

[0014] In another embodiment, the contact spring or the adjusting drive can be mechanically coupled to the articulated arm device via a lever of an actuating mechanism of the spring assembly. The lever can be arranged on the articulated arm device or non-rotatably connected to it such that a movement of the lever causes a movement of the articulated arm device. Initially, it is irrelevant whether the contact spring or the adjusting drive is directly connected to the lever. The actuating mechanism formed by the lever allows the adjusting force and the spring force of the contact spring, or the resulting contact force, to be easily transmitted to the articulated arm device.

[0015] Furthermore, the contact spring can be mechanically coupled to the adjustment drive via a tension lever of a tensioning mechanism within the spring assembly. The tension lever can, for example, be pivotally mounted on a fixed bearing of the positioning unit, with the contact spring and the adjustment drive each acting on or connected to the tension lever via a common or different bearing axes. When the contact surface is already in contact with the charging contact and, consequently, movement of the articulated arm is no longer possible, movement of the adjustment drive is transmitted to the spring via the tension lever of the tensioning mechanism. The spring force stored in the contact spring is then exerted on the articulated arm due to the mechanical series connection of the contact spring and the adjustment drive. The spring force of the contact spring then forms the contact force on the contact surface.If the contact force is many times greater than the adjustment force required to move the articulated arm device, the contact force can essentially always be kept constant, regardless of the height of a vehicle roof relative to the positioning unit.

[0016] It is particularly advantageous if the contact spring is a tension spring. While the contact spring can also be a compression or torsion spring in principle, using a tension spring allows for a particularly compact positioning unit.

[0017] The positioning drive can include a backup battery. In the event of a power failure or other malfunctions, the positioning drive can then automatically retract the positioning unit into a retracted position thanks to the emergency power supply provided by the backup battery. The backup battery can be integrated into the positioning drive or located elsewhere on the vehicle.

[0018] The adjustment drive can be a linear drive, preferably a spindle drive. Optionally, the spindle drive can be designed to be self-locking, depending on the spindle pitch. The articulated arm device can then be easily moved into a desired position and fixed without additional tools.

[0019] Furthermore, the linear actuator can be equipped with a magnetic brake. This is particularly advantageous if the pitch of a spindle drive does not provide self-locking of the drive, or if external forces acting on the articulated arm allow the actuator to move in an undesired direction. The magnetic brake then maintains the generated contact force by fixing the linear actuator. However, in the event of unwanted vehicle movement, the linear actuator, and thus the articulated arm, can still be moved if the braking force of the magnetic brake on the linear actuator is exceeded. This prevents damage to the linear actuator and the articulated arm. In the event of a power failure or other malfunctions, the magnetic brake can also lose its magnetic effect, allowing the actuator to move freely.The positioning unit can then be moved into a retracted position by means of a lifting spring and / or an emergency power supply for the adjustment drive or the linear drive. The magnetic brake can be designed as a normally open (NO) brake or a normally closed (NC) brake with magnetic action.

[0020] The linear actuator can be equipped with a position sensor. Using this sensor allows you to define the range within which the articulated arm can be moved by the linear actuator. For example, an incremental or absolute encoder can be used as the position sensor. This also makes it possible to always determine the precise working position of the linear actuator. The linear actuator can also have position-dependent limit switches and / or force-dependent pressure switches. Furthermore, the contact force can be limited by restricting the linear actuator's extension to a specific end position. Pressure switches can also be used to limit the contact force, either alone or in conjunction with the limit switches.A pressure switch can be located directly at the charging contact or at the drive device in the area of ​​the spring assembly or the adjustment drive.

[0021] The articulated arm device can be designed as a single-arm system, a multi-part scissor system (preferably with a parallelogram linkage), or a pantograph. This allows the articulated arm system to enable parallel movement of the charging contact from its retracted position to its contact position on the vehicle's contact surface. Damping elements can also be incorporated into the articulated arm device to ensure smooth movement.

[0022] It is also advantageous if the lifting spring is a tension spring. This allows for a particularly compact design of the positioning unit. However, it is also possible to use a compression spring, a torsion spring, or a coil spring instead of a tension spring. Instead of a single spring, multiple springs coupled together in a mechanical parallel circuit can also be used.

[0023] The lifting spring can be mechanically coupled to the articulated arm via a lever of a return mechanism within the spring assembly. The effective length of the lever can be variable depending on the position of the articulated arm. The lever can therefore be directly attached to the articulated arm, allowing the spring force of the lifting spring to be directly transmitted to the articulated arm. Depending on the position and direction of the spring force and the arrangement of the lever on the articulated arm, the effective length of the lever can be shortened if the angle between the direction of the spring force and the extension of the lever is less than or greater than 90°. The effective length of the lever can also be varied by attaching the lifting spring to the articulated arm via a return mechanism, for example, a cam or a tie rod with a stop.The cam disc then forms the lever of the return mechanism. Depending on the cam disc's position relative to the lifting spring, the effective length of the lever can be influenced. This makes it possible to apply the same return force to the articulated arm regardless of its position, or to increase or decrease the return force as required depending on the articulated arm's position. The return force can also be adjusted to the adjustment force and the contact force. It is advantageous if the return force is dimensioned such that, in any position of the articulated arm, if the adjustment drive fails (for example, due to a power outage), the charging contact retracts automatically as a result of the return force. This ensures particularly reliable operation of the positioning unit.

[0024] The positioning unit can include a mounting frame for attaching it to a mast or underpass. The mounting frame can, for example, incorporate fixed bearings for the articulated arm and the drive unit. In particular, the contact spring or the adjustment drive can be directly attached to a fixed bearing on the mounting frame. The mounting frame can also be easily attached to the mast or underpass, as well as to the canopy of a bus stop, a tunnel, or similar structures that a vehicle can pass under.

[0025] It is particularly advantageous if the positioning unit has a pivoting device by means of which, in a retracted position of the positioning unit, the charging contact can be pivoted from a vertical contact position to a storage position. If, for example, the charging contact has comparatively large dimensions, such as roof-shaped guide surfaces for bringing it close to the contact surface, the pivoting device can pivot the charging contact from the vertical contact position to the storage position, whereby the charging contact can preferably be stored in a horizontal position. The positioning unit thus has a particularly flat profile in the retracted position and can also be easily driven under by other vehicles of considerable height, such as trucks, without any risk of collision with the positioning unit.The pivoting device can, for example, comprise a cam disc that interacts with a lever located at the lower end of the articulated arm assembly. When moving into the retracted position, the lever can engage the cam disc and pivot along the cam disc. This pivoting motion can be used to pivot the charging contact, which is attached to the lower end of the articulated arm assembly. In simpler embodiments, it is also conceivable to use only a lever or a cam disc to form the pivoting device.

[0026] The charging station according to the invention comprises an electrical charging contact and the positioning unit according to the invention. Advantageous embodiments of a charging station are described in the dependent claims relating to claim 1.

[0027] In the inventive method for forming an electrically conductive connection between a vehicle, in particular an electric bus or the like, and a charging station, an electrical contact of the charging station is moved relative to a contact surface of the vehicle by means of a positioning unit above the vehicle and is made to contact with it, wherein an articulated arm device of the positioning unit is driven by a drive device of the positioning unit, wherein an adjusting drive of the drive device exerts an adjusting force on the articulated arm device and a spring device of the drive device mechanically interacts with the adjusting drive, wherein at least one lifting spring of the spring device exerts a restoring force on the articulated arm device, wherein the restoring force is greater than a weight force of the articulated arm device acting opposite to the lifting spring.wherein the adjusting drive and a contact spring of the spring assembly are coupled to each other in a mechanical series circuit, and a contact force is formed on the contact surface by the adjusting drive and the contact spring. Regarding the advantageous effects of the method, reference is made to the description of advantages of the positioning unit according to the invention.

[0028] The charging contact can be positioned between a contact position for current transmission, an extension position for current interruption, and a retraction position for storing the charging contact by means of the articulated arm device and the drive device. It can be provided that in the contact position, the contact force is applied to the contact surface, and in the extension position, which can be any position between the contact position and the retraction position, only the adjustment force acts on the articulated arm device. In the retraction position, no or only a very small adjustment force can act on the articulated arm device, so that a downward movement of the articulated arm device or the charging contact is not possible.

[0029] Advantageously, the contact position can be configured independently of the relative distance between the vehicle's contact surface below the positioning unit and the positioning unit's entry position. This makes it possible to contact vehicles of varying heights relative to the road surface with the positioning unit. Preferably, the vehicle's contact surface can be located on the vehicle's roof or at another suitable location on the upper surface of the vehicle.

[0030] It is particularly advantageous if the contact force remains constant during changes in the relative distance between the vehicle's contact surface below the positioning unit and the positioning unit's entry position. A change in the relative distance of the contact surface also results in a change in the distance of the contact surface to the roadway. Such a change in the relative distance can be caused by lowering the vehicle via its suspension or by the vehicle's load. Because the contact force is comparatively large relative to the adjustment force, it can remain essentially constant even when the relative distance changes.A constant contact force can be achieved even more easily, independent of the relative distance, if the effective lengths of levers on which the contact spring and / or the adjusting drive act are changed depending on the position of the articulated arm device.

[0031] To establish the contact force in the contact position, the actuator can be moved to an adjustment position with a maximum travel range, whereby the contact force can be transmitted from the contact spring to the actuator. If the actuator is a linear actuator, it can be moved between a maximum and a minimum travel range. In the retracted position, the actuator can be in the position with the minimum travel range. Movement of the articulated arm into the extended position is achieved by the actuator increasing its travel range, thus exerting the adjusting force on the articulated arm and moving it. The contact spring is unloaded during this process, as it is coupled to the actuator in a mechanical series circuit.However, it is also possible to pre-tension the contact spring in the positions described above, for example, using a tension lever. Once the contact position is reached, the articulated arm device cannot be moved further, so any further increase in the adjustment range up to the maximum adjustment range causes the contact spring to be pre-tensioned by the adjustment drive. If the contact spring is already pre-tensioned, the pre-tension is then increased. The spring force thus exerted by the contact spring acts directly or indirectly on the articulated arm device via the adjustment drive and generates the contact force at the contact surface. This makes it possible to generate a largely constant contact force regardless of the relative position of the charging contact in the contact position, without requiring measurement of the contact force or special adjustments in the positioning unit for the vehicles to be contacted.

[0032] Further embodiments of the method are set out in the dependent claims relating to device claim 1.

[0033] A preferred embodiment of the invention is explained in more detail below with reference to the accompanying drawings.

[0034] They show: Fig. 1a a positioning unit in a retracted position in a side view from the left; Fig. 1b the positioning unit in an upper extension position in a side view from the left; Fig. 1c the positioning unit in an upper contact position in the side view from the left; Fig. 1d the positioning unit in a middle extension position in the side view from the left; Fig. 1e the positioning unit in a middle contact position in the side view from the left; Fig. 1f the positioning unit in a lower contact position in the side view from the left; Fig. 2a a positioning unit in the insertion position in a side view from the right; Fig. 2b the positioning unit in the upper extension position in a side view from the right; Fig. 2c the positioning unit in the upper contact position in the side view from the right; Fig. 2d the positioning unit in the middle extension position in the side view from the right; Fig. 2e the positioning unit in the middle contact position in the side view from the right; Fig. 2f the positioning unit in the lower contact position in the side view from the right; Fig. 3 the positioning unit in the insertion position in the side view from the right; Fig. 4 the positioning unit in the upper contact position in the side view from the right; Fig. 5 the positioning unit in the lower contact position in the side view from the right.

[0035] A summary of Fig. Figures 1a to 2f show a positioning unit 10 in different views and positions. Fig.Figures 3 to 5 show the positioning unit 10 in a schematically supplemented representation. The contacting of a contact surface (not shown here) is only symbolically illustrated. The positioning unit 10 comprises an articulated arm device 11 and a drive device 12 for driving the articulated arm device 11. The articulated arm device 11 is designed as a single-arm system 13 and comprises an upper scissor 14 with an upper scissor arm 15 and an upper coupling rod 16, as well as a lower scissor 17 with a lower scissor arm 18 and a lower coupling rod 19. An upper coupling element 20 is pivotably attached to the upper scissor arm 15, so that a holder 21 of the positioning unit 10 for an electrical charging contact (not shown here) of a charging station (also not shown here) can always be moved parallel to a horizontal plane 22. For this purpose, the upper coupling element 20 is connected to the upper coupling rod 16.The lower scissor arm 18 and the lower coupling rod 19 are each pivotably mounted on fixed bearings 23 and 24, respectively, on a support frame 25 of the positioning unit 10. The lower scissor arm 18 is pivotally connected to the upper scissor arm 15 via an axis 26, and the lower coupling rod 19 is pivotally connected to the upper scissor arm 15 via an axis 27. A pivoting movement of the upper scissor arm 15 consequently results in a parallel movement of the support 21 relative to the horizontal plane 22. A damping element 28 is attached to the lower scissor arm 18 to dampen this movement.

[0036] The drive device 12 comprises an adjustment drive 29, designed as a linear drive 30, and a spring assembly 31 with a contact spring 32, designed as a tension spring 33, and a lifting spring 34, designed as a tension spring 35. The lifting spring 34 is attached to a fixed bearing 36 on the support frame 25 and to an axle 37 of a lever 38. A mounting section 39 connects the lever 38 to the lifting spring 34. The lever 38, together with the mounting section 39 and a stop 40, forms a return mechanism 41. Depending on the position of the articulated arm device 11, the lever 38, which is rotationally fixed to the lower scissor arm 18, pivots relative to the lifting spring 34, thus shortening or lengthening the effective length of the lever 38. In a retracted position 42, an upper extension position 43 and an upper contact position 44 of the positioning unit 10, the lifting spring 34 acts directly on the axis 37.In a middle extended position 45, a middle contact position 46, and a lower contact position 47 of the positioning unit 10, the mounting section 39 rests against the stop 40, so that the effective length of the lever 38 is significantly shortened by pivoting it. This makes it possible to adjust the lifting spring 34, or rather its effective restoring force, to a position of the positioning unit 10. The articulated arm device 11, together with the drive device 12, has a design-related weight force, including a charging contact (not shown), which acts on the charging contact or the holder 21. The lifting spring 34 generates a spring force, or restoring force, that exceeds the weight force, so that, regardless of the position of the positioning unit 10, even in the event of a power failure, the positioning unit 10 always returns to the retracted position 42.

[0037] A lever 48 is fixedly attached to the articulated arm device 11 or the lower scissor arm 18, forming an actuating mechanism 49 for the articulated arm device 11. The linear actuator 30 is pivotably mounted on an axis 50 of the lever 48. The linear actuator 30 is further connected to the contact spring 32 in a mechanical series connection 53 via a clamping lever 51 of a clamping mechanism 52. The clamping lever 51 is pivotably mounted to a fixed bearing 54 on the mounting frame 25, with an axis 56 arranged on a central section 55 of the clamping lever 51 and an axis 58 on an end section 57 of the clamping lever 51. The contact spring 32 is attached to a fixed bearing 59 on the mounting frame 25 and to the axis 56, with the linear actuator 30 being attached to the clamping lever 51 at axis 58 and to the lever 48 at axis 50.

[0038] In the retracted position 42, the linear actuator 30 has a minimum travel 60, so no actuating force is exerted on the lever 48. The contact spring 32 is also relaxed. In, for example, the middle extension position 45, the linear actuator 30 has a medium travel 61 and thus exerts an actuating force on the lever 48, overcoming the restoring force of the lifting spring 34 and allowing the articulated arm device 11 to move into the middle extension position 45. The actuating force is so large that the restoring force is overcome by the sum of the weight force and the actuating force. In, for example, the middle contact position 46, the linear actuator 30 has a maximum travel 62, whereby the position of the lever 48 remains unchanged relative to the middle extension position 45. The maximum adjustment range 62 causes the clamping lever 51 to pivot around the fixed bearing 54 in such a way that the contact spring 32 is tensioned.The spring force resulting from the spring tension thus generated acts, due to the mechanical series connection 53 of contact spring 32 and linear actuator 30, on the lever 48 and thus on the articulated arm device 11, thereby generating a contact force on the holder 21 or the charging contact (not shown here). The contact force is sufficiently high to form an electrical charging contact and can be maintained at a substantially constant level in the upper contact position 44, the middle contact position 46, and the lower contact position 47, as well as in any other contact position between those shown here.

[0039] The positioning unit 10 further comprises a pivoting device 63 for the charging contact (not shown) or for the holder 21. By means of the pivoting device 63, the holder 21 can be pivoted horizontally from a vertical contact position 64 parallel to the horizontal plane 22 into a storage position 65 in the retracted position 42. The pivoting device 63 includes a lever 66 on the upper coupling member 20 and a cam disk 67, fixedly arranged on the lower scissor arm 18. When the articulated arm device 11 is returned to the retracted position 42, the lever 66 engages the cam disk 67 such that the lever 66 slides along the cam disk 67 and pivots. The pivoting of the lever 66 causes the holder 21 or the upper coupling member 20 to rotate into the storage position 65 by approximately 90°.

Claims

[1] Positioning unit (10) for a charging station of an electrically powered vehicle, in particular an electric bus or the like, wherein the positioning unit is designed to be arranged above a vehicle, wherein an electrical charging contact of the charging station is movable relative to a contact surface of the vehicle and can be made contact with it by means of the positioning unit, wherein the positioning unit has an articulated arm device (11) and a drive device (12) for driving the articulated arm device, wherein the drive device has an adjustment drive (29) for generating an adjustment force acting on the articulated arm device and a spring device (31) that mechanically interacts with the adjustment drive, wherein the spring device comprises at least one lifting spring (34) for generating a restoring force on the articulated arm device,where the restoring force is greater than a weight force of the articulated arm device acting in the opposite direction to the lifting spring, . characterized by , that the spring device comprises at least one contact spring (32), wherein the adjusting drive and the contact spring are coupled together in a mechanical series connection (53) such that a contact force can be exerted on the contact surface by the adjusting drive and the contact spring. [2] Positioning unit according to claim 1, characterized by , that the contact spring (32) is coupled to the adjusting drive (29) via a floating bearing (56, 58), wherein the contact spring (32) or the adjusting drive is held on a fixed bearing (59). [3] Positioning unit according to claim 1, characterized by , that the contact spring (32) or the adjusting drive (29) is mechanically coupled to the articulated arm device (11) via a lever (48) of an actuating gear (49) of the spring assembly (31). [4] Positioning unit according to any of the preceding claims, characterized by , that the contact spring (32) is mechanically coupled to the adjusting drive (29) via a tension lever (51) of a tensioning mechanism (52) of the spring assembly (31). [5] Positioning unit according to any of the preceding claims, characterized by , that the contact spring (32) is a tension spring (33). [6] Positioning unit according to any one of the preceding claims, characterized by , that the adjustment drive (29) has a buffer battery. [7] Positioning unit according to one of the preceding claims, characterized by that the adjustment drive (29) is a linear drive (30), preferably a spindle drive. [8] Positioning unit according to claim 7, characterized by , that the linear drive (30) has a magnetic brake. [9] Positioning unit according to claim 7 or 8, characterized by , that the linear drive (30) has a displacement sensor. [10] Positioning unit according to any of the preceding claims, characterized by that the articulated arm device (11) is designed as a single-arm system (13) or as a scissor system, preferably with a parallelogram guide, or as a pantograph. [11] Positioning unit according to any of the preceding claims, characterized by , that the lifting spring (34) is a tension spring (35). [12] Positioning unit according to any of the preceding claims, characterized by , that the lifting spring (34) is mechanically coupled to the articulated arm device (11) via a lever (38) of a return gear (41) of the spring assembly (31), wherein an effective length of the lever is designed to be variable depending on a position (42, 43, 44, 45, 46, 47) of the articulated arm device. [13] Positioning unit according to one of the preceding claims, characterized by, that the positioning unit (10) includes a mounting frame (25) for attaching the positioning unit to a mast or underpass. [14] Positioning unit according to any of the preceding claims, characterized by , that the positioning unit (10) has a pivoting device (63) by means of which, in a retracted position (42) of the positioning unit for storing the charging contact, the charging contact can be pivoted from a vertical contact position (64) to a storage position (65). [15] Charging station comprising an electrical charging contact and a positioning unit (10) according to any of the preceding claims. [16] Method for forming an electrically conductive connection between a vehicle, in particular an electric bus or the like, and a charging station, wherein an electrical charging contact of the charging station is moved relative to a contact surface of the vehicle and contacted by means of a positioning unit (10) above a vehicle, wherein an articulated arm device (11) of the positioning unit is driven by a drive device (12) of the positioning unit, wherein an adjustment drive (29) of the drive device exerts an adjustment force on the articulated arm device and a spring device (31) of the drive device mechanically interacts with the adjustment drive, wherein at least one rebound spring (34) of the spring device exerts a restoring force on the articulated arm device, wherein the restoring force is greater than a weight force of the articulated arm device acting opposite to the rebound spring. characterized by, that the adjusting drive and a contact spring (32) of the spring assembly are coupled together in a mechanical series connection (53), and a contact force is formed on the contact surface by the adjusting drive and the contact spring. [17] Method according to claim 16, characterized by , that the charging contact is positioned by means of the articulated arm device (11) and the drive device (12) between a contact position (44, 46, 47) for current transmission, an extension position (43, 45) for current interruption and a retraction position (42) for storing the charging contact. [18] Method according to claim 17, characterized by , that the contact position (44, 46, 47) is formed independently of a relative distance of the contact surface of the vehicle below the positioning unit (10) to the entry position (42) of the positioning unit. [19] Method according to claim 17 or 18, characterized by, that in the contact position (44, 46, 47) during a change in the relative distance of the contact surface of the vehicle below the positioning unit (10) to the entry position (42) of the positioning unit the contact force is constant. [20] Method according to any one of claims 17 to 19, characterized by , that to form the contact force in the contact position (44, 46, 47) the adjusting drive (29) is moved into an adjusting position with a maximum adjustment travel (62), whereby the contact force is transferred from the contact spring (32) to the adjusting drive.

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