DE102020120562A1 - Vehicle trailer and tractor-trailer combination with such a vehicle trailer - Google Patents

Abstract

The present invention relates to a vehicle trailer (10) with a loading bridge (11) and a drawbar (12), which are coupled to a chassis frame (13), and at least one lifting device (14) which has at least one hydraulic cylinder (15) which is articulated with the loading bridge (11) and the drawbar (12), whereby the loading bridge (11) can be moved into a rear tilt position and the drawbar (12) can be adjusted in height by the hydraulic cylinder (15), with the loading bridge (11) in the rear tilt position forms an access ramp, the lifting device (14) having at least one first hydraulic connection (16) for a hand pump (18) and at least one second hydraulic connection (17) for a hydraulic system of a towing vehicle, through which the hydraulic cylinder (15) with the hand pump (18 ) and the hydraulic system of the towing vehicle can be or is hydraulically connected, the lifting device (14) being adapted in such a way that the hydraulic cylinder (15 ) when actuated by the hand pump (18), the drawbar (12) for coupling to the towing vehicle is height-adjusted or the hydraulic cylinder (15) moves the loading bridge (11) into the rear-tipping position for loading and unloading when actuated by the hydraulic system of the towing vehicle. The invention also relates to a train set.

Description

The invention relates to a vehicle trailer and a tractor-trailer combination with such a vehicle trailer. A vehicle trailer according to the preamble of claim 1 is for example from US 2017/008 441 A1 known.

Vehicle trailers are used in the construction industry and in other areas, in addition to transporting cargo, as well as transporting vehicles. The vehicle trailers can, for example, be designed as a high-loader or low-loader, with these having an access ramp for driving on a vehicle. When vehicles with low ground clearance are driven on, there is a risk that the vehicles will often touch down in the area of the transition between the loading ramp and the loading bridge of the vehicle trailer. Furthermore, when driving over the transition in the direction of travel, tracked vehicles can tip over in an uncontrolled manner, as a result of which the vehicle trailer and the tracked vehicle can be damaged.

In order to make it easier to load a vehicle trailer, they have been further developed in such a way that the loading bridge or the chassis frame with the loading bridge can be moved into a rear-tipping position. Such a vehicle trailer is for example from the aforementioned US 2017/008 441 A1 known, which has a height-adjustable drawbar in addition to the tiltable dock leveler. A hydraulic cylinder is provided for tilting the loading bridge and for adjusting the drawbar, which is actuated by an electrically driven hydraulic pump. The hydraulic pump is part of an independent hydraulic circuit on the trailer.

In the known vehicle trailer, the height adjustment of the drawbar is combined with the rearward tilting of the loading bridge. An optimal drawbar height for coupling to a towing vehicle is therefore difficult to fine-tune, since the dock leveler tilts when the drawbar is adjusted. Furthermore, the electric hydraulic pump can only provide limited hydraulic pressures for loading and unloading heavy construction vehicles, for example.

The invention is therefore based on the object of specifying a vehicle trailer which, through improved adaptability, simplifies loading and unloading and coupling to a towing vehicle. Furthermore, the invention is based on the object of specifying a tractor-trailer combination with such a vehicle trailer.

According to the invention, this object is achieved with regard to the vehicle trailer by the subject matter of claim 1. With a view to the tractor-trailer combination, the above-mentioned object is achieved by the subject matter of claim 11.

Specifically, the object is achieved by a vehicle trailer with a loading bridge and a drawbar, which are coupled to a chassis frame, and at least one lifting device. The lifting device has at least one hydraulic cylinder which is articulated to the loading bridge and the drawbar. The hydraulic cylinder can be used to transfer the dock leveler into a rear tilt position and the height of the drawbar can be adjusted. In the rear tipping position, the loading bridge forms an access ramp. The lifting device has at least one first hydraulic connection for a hand pump and at least one second hydraulic connection for a hydraulic system of a towing vehicle, through which the hydraulic cylinder can be or is hydraulically connected to the hand pump and the hydraulic system of the towing vehicle. The lifting device is adapted in such a way that the hydraulic cylinder, when actuated by the hand pump, adjusts the height of the drawbar for coupling to the towing vehicle, or the hydraulic cylinder, when actuated by the hydraulic system of the towing vehicle, moves the loading bridge into the rear-tipping position for loading and unloading.

The invention has several advantages. Moving the loading bridge into the rear-tipping position makes it easier for a vehicle to drive over the loading bridge. It is particularly advantageous for vehicles with a low ground clearance to drive over the loading bridge without having to touch it down. This also makes it easier for crawler vehicles, such as excavators, to drive onto the dock leveler.

A general distinction is made between an uncoupled state and a coupled state of the vehicle trailer. In the uncoupled state, the vehicle trailer is alone or uncoupled from a towing vehicle. In this state there is no fixed point for the drawbar against which the drawbar can be supported when the hydraulic cylinder is actuated. In the uncoupled state, actuation of the lifting device adjusts the height of the drawbar. The lifting device for adjusting the height of the drawbar is preferably actuated by a hand pump. This has the advantage that the height position of the drawbar can be adjusted easily and with little effort. To operate the hydraulic cylinder, the hand pump can be connected to the first hydraulic connection.

The lifting device is adapted in such a way that in the connected state in which the Hand pump can be connected to the first hydraulic connection, the hydraulic cylinder is hydraulically connected to the hand pump.

The hand pump can be designed as a double-acting hand pump in order to adjust the hydraulic cylinder and thus the height of the drawbar in both directions, in particular up and down. The height position of the drawbar can be adjusted manually via the first hydraulic connection and the hand pump connected to it. The height adjustment of the drawbar can only be carried out via the first hydraulic connection and thus the hand pump. It is advantageous here that the height position of the drawbar can be easily and precisely adjusted using the hand pump. Furthermore, the vehicle trailer according to the invention can be adapted and thus coupled to a large number of towing vehicles with different heights of the coupling points. As a result, the vehicle trailer has increased flexibility of use.

In the coupled state, the vehicle trailer is coupled to a towing vehicle, the drawbar being connected to the coupling point of the towing vehicle. In this state, when the lifting device is actuated, the loading bridge is transferred from a transport position, in particular a non-tilted position, to the rear-tilted position. During the tipping process, the force from the hydraulic cylinder is introduced into the coupling point of the towing vehicle via the drawbar. The coupling point forms a fixed point on which the drawbar is supported.

The loading bridge is preferably transferred from a transport position to the rear-tipping position by actuating the lifting device via the hydraulic system of the towing vehicle on the lifting device. It is only in the coupled state that the lifting device can be actuated by the hydraulic system of the towing vehicle. The hydraulic system uses the motor power of the towing vehicle, whereby a high hydraulic pressure is advantageously provided for tilting the loading bridge on the lifting device. As a result, the loading bridge can also be driven over with heavy vehicles, in particular construction vehicles, in the rear tipping position. Furthermore, this makes loading and unloading the loading bridge considerably easier for the user.

It is also conceivable that the loading bridge can be transferred from a transport position to a rear tilt position by actuating the lifting device alternatively or additionally via the hand pump. This has the advantage that when the vehicle trailer is coupled to towing vehicles that do not have a hydraulic system, the loading bridge can be manually transferred into the rear-tipping position.

The lifting device is adapted in such a way that in the connected state, in which the hydraulic system of the towing vehicle can be connected to the second hydraulic connection, the hydraulic cylinder is hydraulically connected to the hydraulic system of the towing vehicle. By means of the second hydraulic connection and the hydraulic system of the towing vehicle connected to it, the loading bridge can be transferred into the rear-tipping position, in particular semi-automatically.

The loading bridge can only be transferred via the second hydraulic connection and thus the hydraulic system of the towing vehicle.

In the invention, the step of adjusting the height of the drawbar for coupling the vehicle trailer to a towing vehicle and the step of moving the loading bridge into the rear tilt position for driving up and down with a vehicle are clearly separated from one another.

The loading bridge can be connected to the chassis frame in a fixed or articulated manner. The loading bridge comprises a loading area and a reinforcement structure for the loading area arranged below.

Preferred embodiments of the invention are specified in the subclaims.

In a preferred embodiment, the drawbar is articulated on the chassis frame, so that the hydraulic cylinder adjusts a height position of the drawbar by tilting it. The height adjustment of the drawbar takes place when the vehicle trailer is disconnected from a towing vehicle. By actuating the hydraulic cylinder, the drawbar is moved around a bearing point on the chassis frame, so that the height position of a drawbar eye on the drawbar for coupling to the towing vehicle is adjusted. The hydraulic cylinder can be connected to the drawbar in an articulated manner in the longitudinal direction of the drawbar between the bearing point on the chassis frame and the drawbar eye. The height adjustment by tilting is structurally easy to implement, so that costs are saved.

In a further preferred embodiment, the lifting device has at least one valve unit, by means of which the hydraulic cylinder can be or is hydraulically connected to the hand pump or the hydraulic system of the towing vehicle. The valve unit preferably has at least three switching positions, the hydraulic cylinder being hydraulically connected to the hydraulic system of the towing vehicle in a first switching position. In a second switch position, the hydraulic cylinder is connected to the hand pump and the hydraulic system of the The towing vehicle is hydraulically separated. In a third switching position, the hydraulic cylinder is hydraulically connected to the hand pump. The hydraulic cylinder can be easily controlled by the valve unit. The valve unit is used to set the desired operating mode (height adjustment, holding or tilting).

The valve unit preferably has at least two 3/3-way valves which can be hydraulically switched between the hand pump and the hydraulic system of the towing vehicle for actuating the hydraulic cylinder. In other words, the valve unit is designed such that the two 3/3-way valves can be switched between the first and third switching positions in order to hydraulically connect the hydraulic cylinder to the hydraulic system of the towing vehicle or to the hand pump. The 3/3-way valves are inexpensive to purchase and can be easily implemented in the lifting device.

The valve unit also preferably has a locking position in which the hydraulic cylinder is hydraulically separated from the hand pump and the hydraulic system of the towing vehicle, so that the hydraulic cylinder hydraulically fixes the drawbar in a set height position. The blocking position corresponds to the second switching position of the valve unit. In this the set height position of the drawbar, in particular the drawbar eye, is held securely. The drawbar is fixed in the height position by the hydraulic pressure applied to the hydraulic cylinder, which prevents a piston and thus a piston rod of the hydraulic cylinder from moving. An additional, mechanical locking mechanism is not required, which saves costs. This also simplifies the construction of the lifting device.

The two 3/3-way valves are preferably coupled to one another for joint switching. As a result of the coupling, the two 3/3-way valves can be switched jointly, in particular simultaneously, between the three switching positions. This achieves high switching accuracy and high functional reliability of the valve unit.

In a preferred embodiment, the hydraulic cylinder is formed by a double-acting hydraulic cylinder which the valve unit controls hydraulically. Due to the double-acting hydraulic cylinder, the drawbar can be adjusted in a defined manner in both height directions, and the loading bridge can be transferred from a transport position to the rear tilt position or from this back to the transport position. This also enables the drawbar to be fixed at a certain height position and the dock leveler to be held in the rear-tipping position. A safe drive-up of a vehicle onto the loading bridge is thus achieved. This also applies to driving down the vehicle when unloading the loading bridge.

In a further preferred embodiment, the hydraulic cylinder has at least two shut-off valves in order to shut off the hydraulic cylinder. The hydraulic cylinder can hydraulically fix the drawbar in a set height position using the shut-off valves. Furthermore, the shut-off valves have the advantage that in the event of an unexpected pressure drop, for example due to a line break in the connected upstream hydraulic system, an impermissible movement of the hydraulic cylinder is prevented. The hydraulic cylinder can safely hold the position of the drawbar or loading bridge through the shut-off valves.

At least one actuating element, in particular a hand lever, is preferably arranged on the chassis frame, by means of which a further valve unit, in particular a 6/3 way valve, can be actuated in order to move the loading bridge into the rear-tipping position for loading. The further valve unit can be part of the lifting device. The further valve unit can be actuated manually by the actuating element. The actuating element is used to release the hydraulic pressure that can be provided by the hydraulic system of the towing vehicle at the second hydraulic connection. By means of the actuating element, a user on the vehicle trailer can transfer the loading bridge from the transport position to the rear tilt position or transfer it back from the rear tilt position back into the transport position. The user can operate the loading bridge directly on the vehicle trailer and bring it into the desired position.

In a further preferred embodiment, the loading bridge has at least one drive-on tailgate which, in the rear-tilting position, forms part of the access ramp. The tailgate not only serves to limit a loading area of the loading bridge at the rear, but also forms a drive-over element that forms part of the loading ramp. In the rear tilt position, the tailgate can bridge the remaining distance between the floor and the loading area of the loading bridge. In particular, it can be provided that the tailgate essentially forms a straight extension of the loading area of the loading bridge.

According to the independent claim 11, the invention relates to a tractor-trailer combination with a towing vehicle and a vehicle trailer according to the invention, which is hydraulically connected to a hydraulic system of the towing vehicle and / or can be or is connected to a hand pump in such a way that the loading bridge of the vehicle trailer from a transport position to a rear-tipping position is transferable, in which the dock leveler forms a ramp. Reference is made here to the advantages explained in connection with the vehicle trailer. In addition, the tractor-trailer combination can alternatively or additionally have individual features or a combination of several features mentioned above in relation to the vehicle trailer.

The invention is explained in more detail below with further details with reference to the accompanying drawings. The illustrated embodiments represent examples of how the vehicle trailer according to the invention can be configured.

• 1 eine perspektivische Ansicht eines Fahrzeuganhängers nach einem bevorzugten erfindungsgemäßen Ausführungsbeispiel;
• 2 einen Hydraulikschaltplan einer Hubeinrichtung des Fahrzeuganhängers gemäß 1; und
• 3 einen Hydraulikschaltplan einer Hubeinrichtung gemäß dem Stand der Technik.

In these show

• 1 a perspective view of a vehicle trailer according to a preferred embodiment of the invention;
• 2 a hydraulic circuit diagram of a lifting device of the vehicle trailer according to 1 ; and
• 3 a hydraulic circuit diagram of a lifting device according to the prior art.

1 Figure 3 shows a perspective view of a vehicle trailer 10 according to an embodiment of the invention, wherein the vehicle trailer 10 In addition to the transport of cargo, such as building materials, it is also used to transport vehicles. The vehicle trailer 10 according to 1 is designed as a uploader. Alternatively, the vehicle trailer 10 also be designed as a low loader. In general, the invention also includes other types of trailers that are not mentioned.

The vehicle trailer 10 includes a dock leveler 11 , a drawbar 12th and a chassis frame 13th . The dock leveler 11 is with the chassis frame 13th firmly connected. It is also conceivable that the loading bridge 11 with the chassis frame 13th is articulated so that the dock leveler 11 can be converted into one or more tilted positions. The dock leveler 11 also has several side walls that form a loading area 27 limit laterally.

The vehicle trailer 10 has two traversable tailgates at the rear 26th on that with the dock leveler 11 are pivotally connected. The tailgate 26th can be folded back around a transverse axis that runs transversely to the longitudinal direction of the vehicle trailer and are used for loading and unloading the loading bridge 11 , especially for driving up and down vehicles.

According to 1 is the drawbar 12th with the chassis frame 13th articulated. Specifically, the drawbar points 12th two ends up, being the drawbar 12th through a first end with one under the chassis frame 13th arranged bearing point is rotatably coupled. At the second end 28 points the drawbar 12th a towing eye 29 for coupling to a towing vehicle. The drawbar 12th further comprises a draw tube body 31 which extends between the two ends, the first end and the second end 28 have a height offset to each other.

As in 1 shown shows the vehicle trailer 10 furthermore a lifting device 14th with two hydraulic cylinders 15th on that with the dock leveler 11 and the drawbar 12th are articulated. The hydraulic cylinders 15th are essentially based on the drawbar 12th arranged vertically. Through the hydraulic cylinders 15th is the dock leveler 11 can be converted into a rear tilt position and the drawbar 12th height adjustable.

Around the dock leveler 11 The vehicle trailer must be able to move into the rear tilt position 10 with the drawbar 12th be coupled to a towing vehicle, not shown. During the tilting process, the force is taken from the hydraulic cylinders 15th over the drawbar 12th initiated into the coupling point of the towing vehicle. The coupling point forms a fixed point on which the drawbar is located 12th supports. When adjusting the height of the drawbar 12th is the vehicle trailer 10 uncoupled from a towing vehicle. The drawbar 12th is not coupled to any coupling point, so that the drawbar 12th is freely adjustable.

The lifting device 14th is adapted so that the adjustment of the height position of the drawbar 12th and the transfer of the dock leveler 11 can be done in the rear tilt position independently. The drawbar 12th is connected to the bearing point in such a way that the hydraulic cylinder 15th a height position of the drawbar 12th Adjust by tilting or swiveling around the bearing point. The dock leveler 11 forms a drive-on ramp in the tilt-back position, with the drive-on tailgate 26th are part of the access ramp in the rear tilt position. The tailgate 26th can do a straight extension of the loading area 27 the dock leveler 11 form.

The lifting device 14th has two separate hydraulic connections 16 , 17th on, with a first hydraulic connection 16 for a hydraulic hand pump 18th and a second hydraulic connection 17th is provided for a hydraulic system of a towing vehicle, not shown. In other words, the two are hydraulic cylinders 15th through the first hydraulic connection 16 with the hand pump 18th hydraulically connectable and through the second hydraulic connection 17th Can be hydraulically connected to the hydraulic system of the towing vehicle.

As in 1 can be seen are the hydraulic connections 16 , 17th on the front of the chassis frame 13th arranged. The first hydraulic connection is concrete 16 on the right-hand side of the chassis frame in the direction of travel 13th and the second hydraulic connection 17th on the left side of the chassis frame in the direction of travel 13th arranged. It is also in the area of the second hydraulic connection 17th an actuator 24 a valve unit 25th in the form of a hand lever 24 ' intended. By the hand lever 24 ' can the valve unit 25th be operated. On the valve unit 25th will be discussed in more detail later.

The lifting device 14th of the vehicle trailer 10 according to 1 is based on 2 described in more detail below. 2 shows a hydraulic circuit diagram of the lifting device 14th , the hydraulic hand pump 18th and the hydraulic system of the towing vehicle at the associated hydraulic connection 16 , 17th are shown connected for better explanation. Furthermore, in 2 for the sake of simplicity, only one of the two hydraulic cylinders 15th shown, the following description also on the second hydraulic cylinder, not shown 15th applies.

As in 2 shown is the hydraulic cylinder 15th formed by a double-acting hydraulic cylinder. The hydraulic cylinder 15th has two check valves 23 on the hydraulic cylinder 15th are connected upstream. One stop valve each 23 is in one of two hydraulic lines 32 ' , 32 " arranged. The two hydraulic lines 32 ' , 32 " serve a piston rod of the hydraulic cylinder depending on the direction of movement 15th as an inlet or outlet line for hydraulic oil.

The lifting device 14th comprises a valve unit 19th through which the hydraulic cylinder 15th with the hand pump 19th or the hydraulic system of the towing vehicle or from the hand pump 19th and the hydraulic system of the towing vehicle is hydraulically separated. The valve unit 19th has two 3/3-way valves 21 which are coupled to one another in such a way that the two 3/3-way valves 21 operated simultaneously. In other words, the 3/3-way valves 21 operated simultaneously during a switching process. The 3/3-way valves 21 can be operated electrically. Alternatively, the 3/3-way valves 21 mechanically, in particular manually, are operated.

The two 3/3-way valves 21 have three switch positions 33 , 34 , 35 on, in a first switching position 33 the hydraulic cylinder 15th is hydraulically connected to the hydraulic system of the commercial vehicle. In a second switch position 34 is the hydraulic cylinder 15th from the hand pump 18th and the hydraulic system of the towing vehicle hydraulically separated. In a third switch position 35 is the hydraulic cylinder 15th with the hand pump 18th hydraulically connected. The second switch position 34 corresponds to a locked position 22nd .

The lifting device 14th is adapted so that the transfer of the dock leveler 11 only via the second hydraulic connection 17th and thus the hydraulic system of the towing vehicle can be carried out. In the first switch position 33 becomes the hydraulic cylinder 15th hydraulically controlled such that the piston rod of the hydraulic cylinder 15th extends or retracts. To the hydraulic cylinder 15th with the one on the second hydraulic connection 17th To hydraulically connect the connected hydraulic system of the towing vehicle, the additional, in 1 called, valve unit 25th via the hand lever 24 ' operated manually. The further valve unit 25th is designed as a 6/3-way valve. The two 3/3-way valves 21 are between the hydraulic cylinder 15th and the hand pump 18th as well as the 6/3-way valve.

By actuating the further valve unit 25th the hydraulic flow or the hydraulic pressure of the hydraulic system of the towing vehicle is released, so that the loading bridge 11 is transferred from a transport position to a rear tilt position. The dock leveler can thereby 11 and the drawbar 12th move relatively. The vehicle trailer is in this state 10 with the towing eye 29 coupled to a coupling point of a towing vehicle, not shown. The dock leveler is in the rear tilt position 11 inclined or at an angle so that a vehicle is easier to get onto the dock leveler 11 can drive up or move away from this.

Around the dock leveler 11 The two 3/3-way valves can be used to hold in the rear tilt position 21 the valve unit 19th into the second switch position 34 or locked position 22nd be moved. Furthermore, the 6/3 way valve of the further valve unit 25th a locked position that the dock leveler 11 can additionally or alternatively fix hydraulically in the rear tilt position. The dock leveler is in the locked position 11 by the pressurized hydraulic oil in the two hydraulic lines 32 ' , 32 " between the hydraulic cylinder 15th and the two 3/3-way valves 21 or the 6/3-way valve is included, fixed in their position. In other words, the dock leveler becomes 11 held by the enclosed hydraulic pressure in the rear tilt position when driving up or down the vehicle, in particular fixed.

After the vehicle has driven up or down, the dock leveler can 11 by actuating the further valve unit 25th by the hand lever 24 ' and by switching the 3/3-way valves 21 in the first switch position 33 from the rear tilt position be transferred back to the transport position. It is conceivable that the 3/3-way valves 21 during the transfer of the dock leveler 11 from the transport position to the tilt-back position are always in the first switch position, ie they do not have a blocking function.

As described above, it is in the third switching position 35 the 3/3-way valves 21 the hydraulic cylinder 15th with the hand pump 18th hydraulically connected and hydraulically separated from the hydraulic system of the towing vehicle. By manually operating the hand pump 18th becomes the hydraulic cylinder 15th depending on a switching position of a pump valve 36 operated accordingly. The vehicle trailer is in this state 10 preferably uncoupled from a towing vehicle, not shown. This is done by the hand pump 18th the height position of the towing eye 29 a coupling height of a towing vehicle adjustable. The lifting device 14th is adapted so that the height adjustment of the drawbar 12th via the first hydraulic connection 16 and thus the hand pump 18th is feasible. The drawbar 12th can be done with the hand pump 18th via the hydraulic cylinder 15th can be adjusted upwards or downwards in the raising direction. In other words, it is the drawbar 12th adjustable so that the towing eye 29 can be moved in both height directions for coupling to a towing vehicle.

Is the vehicle trailer 10 coupled to a towing vehicle and the 3/3-way valve is located 21 in the third switch position, the hand pump can also be used 18th the dock leveler 11 be transferred from the transport position to the rear tilt position.

3 shows a hydraulic circuit diagram of a lifting device 14th according to the state of the art. In contrast to the lifting device 14th according to 2 is not a valve unit 19th present to the hydraulic cylinder 15th to be actuated by a hydraulic system of a towing vehicle. The second hydraulic connection is also missing 17th the lifting device 14th . The height adjustment of the drawbar 12th and the transfer of the dock leveler 11 from the transport position to the rearward tilt position is only possible with the hand pump 18th possible.

List of reference symbols

10

Vehicle trailer

11

Dock leveler

12th

Drawbar

13th

Chassis frame

14th

Lifting device

15th

Hydraulic cylinder

16

first hydraulic connection

17th

second hydraulic connection

18th

Hand pump

19th

Valve unit

21

3/3-way valve

22nd

Locked position

23

Shut-off valves

24

Actuator

24 '

Hand lever

25th

further valve unit

26th

Tailgate

27

Loading area

28

second end

29

Towing eye

31

Draw tube body

32 ', 32' '

Hydraulic lines

33

first switch position

34

second switch position

35

third switch position

36

Pump valve

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 2017008441 A1 [0001, 0003]

Claims (11)

Vehicle trailer (10) with a loading bridge (11) and a drawbar (12), which are coupled to a chassis frame (13), and at least one lifting device (14) which has at least one hydraulic cylinder (15) which is connected to the loading bridge (11 ) and the drawbar (12) is articulated, with the hydraulic cylinder (15) transferring the loading bridge (11) into a rear-tipping position and the drawbar (12) being height-adjustable, the loading bridge (11) forming a loading ramp in the rear-tipping position, thereby characterized in that the lifting device (14) has at least one first hydraulic connection (16) for a hand pump (18) and at least one second hydraulic connection (17) for a hydraulic system of a towing vehicle, through which the hydraulic cylinder (15) with the hand pump (18) and is hydraulically connectable or connected to the hydraulic system of the towing vehicle, the lifting device (14) being adapted in such a way that the hydraulic cylinder (15) when actuated The height of the drawbar (12) for coupling to the towing vehicle is adjusted by the hand pump (18) or the hydraulic cylinder (15), when actuated by the hydraulic system of the towing vehicle, moves the loading bridge (11) into the rear-tipping position for loading and unloading. Vehicle trailer after Claim 1 , characterized in that the drawbar (12) is articulated on the chassis frame (13) so that the hydraulic cylinder (15) adjusts a height position of the drawbar (12) by tilting. Vehicle trailer after Claim 1 or 2 , characterized in that the lifting device (14) has at least one valve unit (19) through which the hydraulic cylinder (15) can be or is hydraulically connected to the hand pump (18) or the hydraulic system of the towing vehicle. Vehicle trailer after Claim 3 , characterized in that the valve unit (19) has at least two 3/3-way valves (21) which can be hydraulically switched between the hand pump (18) and the hydraulic system of the towing vehicle to actuate the hydraulic cylinder (15). Vehicle trailer after Claim 3 or 4th , characterized in that the valve unit (19) has a blocking position (22) in which the hydraulic cylinder (15) is hydraulically separated from the hand pump (18) and the hydraulic system of the towing vehicle, so that the hydraulic cylinder (15) supports the drawbar (12) hydraulically fixed in a set height position. Vehicle trailer according to one of the Claims 3 to 5 , characterized in that the two 3/3-way valves (21) are coupled to one another for common switching. Vehicle trailer according to one of the preceding claims, characterized in that the hydraulic cylinder (15) is formed by a double-acting hydraulic cylinder (15) which the valve unit (19) controls hydraulically. Vehicle trailer according to one of the preceding claims, characterized in that the hydraulic cylinder (15) has at least two shut-off valves (23) in order to shut off the hydraulic cylinder (15). Vehicle trailer according to one of the preceding claims, characterized in that at least one actuating element (24), in particular a hand lever, is arranged on the chassis frame (13), by means of which a further valve unit (25), in particular a 6/3 way valve, can be actuated, to move the loading bridge (11) into the rear-tipping position for loading and unloading. Vehicle trailer according to one of the preceding claims, characterized in that the loading bridge (11) has at least one drive-on tailgate (26) which, in the rear-tipping position, forms part of the access ramp. A tractor-trailer combination with a towing vehicle and a vehicle trailer (10) according to one of the preceding claims, which is hydraulically connected to a hydraulic system of the towing vehicle and / or can be connected or connected to a hand pump (18) in such a way that the loading bridge (11) of the vehicle trailer is connected to a Transport position can be converted into a rear tilt position, in which the loading bridge (11) forms an access ramp.

Images