Trailer hitch and motor vehicle with such a trailer hitch

Abstract

Trailer device for a motor vehicle, comprising at least one sword tube (3) which, in the mounting position on the motor vehicle, is inserted into a sword tube receptacle (5) and attached thereto, characterized by a fastening device (8) by which the sword tube (3) can be expanded in the area of ​​the tube section (7) inserted into the sword tube receptacle (5) and brought into a clamping position against the sword tube receptacle (5).

Description

[0001] The invention relates to a trailer device for a motor vehicle, comprising at least one sword tube which, in the mounting position on the motor vehicle, is inserted into a sword tube receptacle and attached thereto.

[0002] Such a towing device is typically attached to the rear of a motor vehicle such as a car or bus. This towing device can be, for example, a bicycle carrier or other load carrier. An example of such a towing device can be found in DE 103 15 690 A1. Such a towing device comprises at least one, usually two, tow bars, which are inserted into and attached to suitable tow bar mounts located on the vehicle side or body side. In the towing device known from DE 103 15 690 A1, the two tow bars are attached by means of a screw connection comprising a sufficiently long screw that is inserted through an opening in the tow bar mount and through two aligned openings in the tow bar, and exits through a lower opening in the tow bar mount, where a fastening nut is screwed on.Although this achieves a secure fix, over time, for example after prior damage such as from slightly bumping the trailer hitch against a wall, a loss of torque can occur in the screw connections, so that the fixation of the trailer hitch is no longer optimal.

[0003] The invention is based on the problem of providing an improved trailer hitch.

[0004] To solve the problem, a towing device of the type mentioned above is characterized by a fastening device by which the sword tube can be expanded in the area of ​​the tube section inserted into the sword tube receptacle and brought into a clamping position against the sword tube receptacle.

[0005] Unlike the prior art, in the towing device according to the invention, the connection of the at least one sword tube to the sword tube holder is achieved via a clamping connection. For this purpose, a corresponding fastening device is provided, which allows the sword tube to be expanded or spread open in the area of ​​the tube section inserted into the sword tube holder, so that it is brought into a clamping position against the inner wall of the sword tube holder. Advantageously, the sword tube and the sword tube holder have a comparable geometry or cross-section; that is, they are both either round or rectangular. Regardless of the specific geometry, in the towing device according to the invention, the fastening device expands or spreads the sword tube end that is inserted into the sword tube holder, so that it is firmly clamped to or within the sword tube holder.This extremely tight clamping mechanism ensures a stable and robust attachment of the sword tube to the sword tube mount, for example, in a longitudinal member of the vehicle body. Screw connections are not used, thus preventing unintentional loosening due to a decrease in tightening torque.

[0006] Preferably, two sword tubes are provided, each with its own separate mounting device. Each sword tube can be expanded via its respective mounting device and clamped to a separate sword tube receptacle. The towing device is therefore permanently and extremely securely attached to the body-side sword tube receptacles via two corresponding clamping connections.

[0007] It is advantageous if the tube section of the sword tube(s) is slotted with one or more slits extending from the free end of the tube section. This slotting makes it easier to spread the tube section and allows it to be spread wide enough to bridge a small gap between the outer circumference or outside of the sword tube and the inner circumference or inside of the sword tube receiver. The slit(s) should preferably extend in a straight line from the free end of the tube section, i.e., parallel to the longitudinal axis of the sword tube, for a length of one or a few centimeters.

[0008] The central feature of the towing device is the mounting mechanism, which establishes the clamping connection between the sword tube and the sword tube receiver. To achieve this, the mounting mechanism, or each mounting mechanism, advantageously incorporates a movable expanding element that can be moved linearly against the tube section to widen it. The linearly movable expanding element is thus moved linearly against the tube section, specifically its inner wall, causing it to widen. This means that the expanding element presses the tube section outwards and into a clamping position against the sword tube receiver.

[0009] For this purpose, the spreading element can advantageously have a spreading surface adapted to the cross-sectional shape of the pipe section, with which the spreading element runs against the pipe section during linear movement. The spreading element is thus moved linearly until its spreading surface runs against the pipe section, and with further linear movement, it expands the pipe section radially or laterally outwards.

[0010] The geometry of the spreading surface is chosen depending on the cross-sectional shape of the sword tube. If the sword tube is round, the spreading surface is expediently conical; if the sword tube is angular, the spreading surface is pyramidal.

[0011] As described, the spreading element is to be moved linearly for expansion or spreading. To achieve this in a simple manner, according to a further development of the invention, the spreading element is connected to a pull rod that extends along the sword tube and is movable along the sword tube to effect the linear movement of the spreading element. Via this pull rod, which can be actuated accordingly by the user, the spreading element is moved linearly and, to spread or clamp, against the tube section, and, to release the connection, also away from it again; i.e., the spreading element can be moved in both directions. Sufficient force can be exerted on the spreading element via such a pull rod, and this in turn exerts a corresponding clamping force on the tube section and thus on the clamping mechanism at the sword tube receiver.

[0012] To enable linear movement of the spreading element via the pull rod, two different designs are conceivable. According to the first variant, the pull rod can be guided by an external threaded section within an internal threaded guide in the sword tube and has a fastening section accessible with a tool. The pull rod is thus screwed into the internal threaded guide, extending through it. An actuating section is provided on the pull rod, which the user can grip with a tool, such as a screwdriver or wrench, to rotate the pull rod. As the pull rod is rotated, it inevitably moves within the internal threaded guide, thus undergoing linear movement, and with it, the spreading element. This threaded guide allows the spreading element to exert a very high tensile force, and consequently a very high spreading force, on the tube section, thereby generating a high clamping force.

[0013] An alternative approach involves connecting the pull rod to a lever mechanism comprising a pivoting actuating lever, which, when actuated, allows the pull rod to move linearly. In this variant, a corresponding lever mechanism, for example, a toggle lever mechanism or similar, is provided, comprising a pivoting actuating lever that the user simply flips, thereby tightening the pull rod and thus linearly moving the spreading element. Conversely, in both variants, the spreading element and thus the clamping connection are also released.

[0014] If an internal thread guide is provided, it is preferably located on a wall closing the sword tube. The drawbar passes through this wall, which is preferably positioned at the end of the sword tube, i.e., in the area of ​​a cross member of the hitch device, so that the actuating section can be formed at the protruding end of the drawbar, which is easily accessible to the user. For example, the end of the drawbar can be provided with a tool holder, which forms the actuating section, for a screwdriver or a ratchet socket, or similar tool.

[0015] The sword tube(s) are arranged on a crossbeam, usually welded to it, as is generally the case. In a further development of the invention, this crossbeam has an opening that allows access to the actuating section. This opening is, for example, formed in axial extension of the drawbar if the tool holder is provided at the free end of the drawbar, i.e., so that the tool can be applied axially to the drawbar, for example with a screwdriver or a ratchet socket. Alternatively, the opening can also be positioned quasi-radially to allow, for example, access to the actuating section with a wrench.

[0016] In addition to the trailer hitch itself, the invention further relates to a motor vehicle comprising one or two sword tube mounts and a trailer hitch of the type described above, which is attached to the sword tube mount(s) via a clamping connection.

[0017] Further advantages and details of the present invention will become apparent from the exemplary embodiments described below and from the drawing. Fig. 1 a perspective view of a trailer attachment device according to the invention in an exploded view, and Fig. 2 A schematic representation of the clamping mechanism for connecting the trailer hitch via a sword tube to a sword tube mount of the vehicle body.

[0018] Fig. Figure 1 shows an exploded view of a towing device 1 according to the invention, comprising a cross member 2 to which two sword tubes 3 are attached, in particular welded. The two sword tubes 3 project from the cross member 2 and run parallel to each other. In the example shown, they have a round cross-section, i.e., they are hollow cylindrical. Two openings 4 are provided in the cross member 2, which allow engagement for a tool through which a fastening device can be actuated. This device enables the respective sword tube 3 to be fixed in a corresponding, form-compatible sword tube receptacle 5 of the motor vehicle or the motor vehicle body via a clamping connection. The two sword tubes 3 themselves are slotted in this area by means of several slots 6, which are provided in the region of the free tube end 7 parallel to the longitudinal axis of the respective sword tube.

[0019] Also shown is a respective fastening device 8 comprising a drawbar 9, at one end of which a spreading element 10 is arranged. In the example shown, this spreading element is conical due to the cross-sectional shape of the sword tube 3 and the sword tube receptacle 5, thus forming a conical spreading surface 11. Each sword tube 3 is assigned such a fastening device 8, or such a drawbar 9, including the spreading element 10. In the assembly position according to Fig. 2, which will be described below, the fastening device 8 is inserted into and extends through the respective sword tube 3. The fastening device 8 makes it possible to widen the tube section 7, which is slotted via the slots 6, and press it into a clamping device against the inner wall of the respective sword tube receptacle 5.

[0020] Fig. Figure 2 shows a sectional view through the attachment device 1 in its mounted position on the two sword tube holders 5, whereby in the example shown only one sword tube 3 and one sword tube holder 5 are shown. The sword tube 3 is inserted into the form-compatible sword tube holder 5; both are cylindrical as described. Inside the sword tube holder 5, the tube section 7, which is longitudinally slotted via the slots 6, is always received. The fastening device 8 is inserted into the respective sword tube 3. The drawbar 9 has, at least in the area of ​​its end opposite the spreading element 10, an external threaded section 12, which is screwed into an internal threaded guide 13 formed on an end wall 14 that closes the sword tube 3. The free end of the drawbar 9 is provided with an actuating section 15 for receiving a tool.To access this actuating section 15, the crossbeam 2 is provided with the respective opening 4. In the example shown, the end of the pull rod 8 is provided with a slot as actuating section 15, into which a screwdriver can be inserted.

[0021] How Fig.As shown in Figure 2, the spreading element 10 is positioned in the area of ​​the pipe section 7 in this position, where the sword tube 3 is inserted into the sword tube receptacle 5 but not yet clamped in place. If, as indicated by arrow P1, the drawbar 9 is screwed into the internal thread guide 13, i.e., rotated by the tool via the actuating section 15, the drawbar 9 and with it the spreading element 10 are moved linearly, as indicated by arrow P2. This causes the spreading element 10 to move towards the pipe section 7, specifically towards its inner edge, i.e., the end of the pipe section 7. Since the diameter of the conical spreading surface 11 increases continuously, with increasing linear displacement the spreading surface 11 moves towards the inner edge of the pipe section, i.e., its end.With continued linear movement, expansion inevitably occurs, causing the pipe section 7 to spread against the inner wall of the sword tube holder 5 and be clamped in an extremely tight position. This expansion is facilitated by the fact that the pipe section 7 is slotted via the slots 6. This also makes it possible to bridge larger differences between the outer diameter of the pipe section 7 and the inner diameter of the sword tube holder 5. The maximum degree of expansion is determined by the maximum diameter of the expanding element 10.

[0022] In this way, the towing device with its two sword tubes 3 can be clamped extremely firmly and robustly in the two sword tube receptacles 5, i.e., held in place by a stable clamping system. Furthermore, this clamping connection is also extremely secure; any loosening or release of the clamping connection is impossible, even if a force is applied to the towing device 1. This is because the fastening device 8 is extremely firmly fixed at both ends: firstly, by means of the extremely tightly wedged or clamped expanding element 10, and secondly, by means of the screw connection of the drawbar 9 via the external threaded section 12 and the internal threaded guide 13. A correspondingly high axial force is generated, which prevents any loosening or release. Actuating the respective fastening device 8 is also simple, as it only requires a tool to be inserted through the opening 4.The opening 4 itself can, for example, be closed by a lid that can be opened accordingly.

[0023] The respective sword tube mounting 5 can, for example, be a longitudinal member of a vehicle body itself, provided it has a corresponding round cross-section. In the case of a rectangular cross-section, each sword tube mounting 5 can be formed by a corresponding mounting bracket attached to the longitudinal member. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 103 15 690 A1

[0002]

Claims

[1] Trailer coupling device for a motor vehicle, comprising at least one sword tube (3) which, in the mounting position on the motor vehicle, is inserted into a sword tube receptacle (5) and attached thereto, characterized by a fastening device (8) by which the sword tube (3) can be expanded in the area of ​​the tube section (7) inserted into the sword tube receptacle (5) and brought into a clamping arrangement on the sword tube receptacle (5). [2] Trailer hitch according to claim 1, characterized by that two sword tubes (3) are provided, each of which has a separate fastening device (8) assigned, wherein each sword tube (3) can be expanded via the respective fastening device (8) and brought in a clamping arrangement to a separate sword tube receptacle (5). [3] Trailer hitch according to claim 1 or 2, characterized by that the or each pipe section (7) is slotted over one or more slots (6) extending from the free end of the pipe section (7). [4] Trailer hitch according to one of the preceding claims, characterized by that the or each fastening device (8) has a movable spreading element (10) which can be moved in a linear motion against the pipe section (7) for expansion. [5] Trailer hitch according to claim 4, characterized by , that the spreading element (10) has a spreading surface (11) adapted to the cross-sectional shape of the pipe section (7), with which the spreading element (10) runs against the pipe section (7) during linear movement. [6] Trailer hitch according to claim 5, characterized by , that the spreading surface (11) is conical or pyramidal. [7] Trailer hitch according to any one of claims 4 to 6, characterized by , that the spreading element (10) is connected to a pull rod (9) which extends along the sword tube (3) and is movable along the sword tube (3) to effect the linear movement of the spreading element (10). [8] Trailer hitch according to claim 7, characterized by , that the drawbar (9) is guided with an external threaded section (12) in an internal threaded guide (13) of the sword tube (3) and has an actuating section (15) accessible with a tool, or that the drawbar (9) is connected with a lever mechanism comprising a pivotable actuating lever, when actuated the drawbar (9) is linearly movable. [9] Trailer hitch according to claim 8, characterized by , that the internal thread guide (13) is provided on a wall (14) closing the sword tube (3). [10] Trailer hitch according to claim 8 or 9, characterized by , that the sword tube or each sword tube (3) is arranged on a crossbeam (2) on which an opening (4) allowing access to the actuating section (15) is provided. [11] Motor vehicle comprising one or two sword tube mounts (5) and a trailer hitch (1) according to one of the preceding claims, which is attached to the sword tube mount(s) (5) via a clamping connection.

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