Patent Application
20090152831
This application is based on German Patent Application No. 10 2007 059 900.7 filed on Dec. 12, 2007, upon which priority is claimed.
1. Field of the Invention
The invention is based on a hitching device with a stabilizer for avoiding and/or damping rolling motions between a traction vehicle and a trailer coupled to this traction device.
2. Description of the Prior Art
One such hitching device with a stabilizer is already known from German Utility Model DE 20316698 U1, for example. This stabilizer is secured to a tow bar of a trailer. It has a pair of friction brake linings, which in the coupled state of the trailer are pressed against a trailer hitch on the end toward the traction vehicle. The tightening force at any given time is brought to bear mechanically or by hydraulic pressure. Because of the adjustability of the tightening force, the friction conditions between the traction vehicle and the trailer can be defined once and for all upon hitching.
German Patent Disclosure DE 3702699 A1 likewise discloses mechanical, pneumatic or hydraulic means for exerting the tightening force and moreover suggests adjusting these tightening forces as a function of the travel speed of the traction vehicle and/or of the total weight of the trailer load.
However, stabilizers acted upon hydraulically and pneumatically have the disadvantage that to maintain the tightening forces during travel, system pressure must be constantly available, so that accordingly such systems are dependent on a permanent supply of energy. Moreover, stabilizers acted upon hydraulically or pneumatically can be economically used only with trailers that are already equipped with a hydraulic or pneumatic trailer brake. However, since a majority of trailers are equipped with mechanical trailer brake systems, these trailers are not readily suited for the use of stabilizers that are actuatable hydraulically or pneumatically.
Mechanically actuated stabilizers, by comparison, have the advantage of a more-economical construction. However, for the driver, manipulating them involves physical exertion and is therefore perceived as uncomfortable. In stabilizer systems that operate mechanically, only unsatisfactory adaptation of the tightening forces to the travel conditions at that time has been possible, until now.
By comparison, a hitching device with a stabilizer according to the invention has the advantage that actuating the stabilizer is done by an electric motor having a downstream gear. The gear has self-locking in the release direction of the stabilizer. Thus energy has to be exerted only to close the stabilizer, or in other words to increase the tightening force, but not for maintaining the tightening force once established. Unintentional release of the stabilizer is avoided by the self-locking.
Stabilizers actuatable by electric motor can be operated without expending physical force, by a manually actuatable user control element. Hence the comfort of hitching a trailer to a traction vehicle can be improved, making even persons with relatively little physical strength also capable of performing the hitching operation.
In addition, stabilizers that can be actuated by an electric motor can be incorporated relatively simply into an electronic control or regulating circuit. From sensors known per se, parameters that describe the travel state of a group comprising a traction vehicle and a trailer are simply ascertained and delivered to an electronic control unit. Without extensive sensors, a conclusion can be drawn as to the tightening force of the stabilizer prevailing at that time, based on the current flowing to the electric motor. By use of the electronic control unit, from its signals, trigger signals can be generated that permit an adaptation of the tightening force of a stabilizer to the travel states of a group during ongoing travel.
Moreover, stabilizers actuated by electric motor are suitable for retrofitting trailers that until now had no stabilizer at all. There are no limitations on the type of trailer brake system, since all mass-produced trailers are already connectable to the electric power supply of the traction vehicle, for instance for operating their lighting system.
The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of preferred embodiments taken in conjunction with the drawings, in which:
In the second exemplary embodiment of
The third exemplary embodiment of
All the stabilizers 30 described function in such a way that upon a change in the direction of rotation of the electric motor 34, the stabilizer 30 can be tightened or released. In the tightening direction, friction brake linings 32 are pressed with increasing tightening force against the ball head 14 of a trailer hitch 12, and the forces of friction between this trailer hitch 12 and a coupling element 18 are thus increased. Conversely, these fiction conditions can be lessened by driving the stabilizer 30 in the release direction.
The invention is not limited to the threaded spindle drives described. Other constructions of gears can equally be imagined, such as worm gears or gear wheel/rack drives. All these types of gears can be designed, in a manner known to one skilled in the art, by the selection of their toothing geometries, in such a way that they have self-locking in the release direction. As a result, the function conditions, once established, cannot vary automatically, or in other words not without the electrical triggering of the electric motor 34.
For furnishing a trigger signal for the electric motor 34, a user control element 70 that is actuatable manually by the driver can be provided, for instance in the form of an electromechanical key or switch. Thus the stabilizer 30, when a trailer is being hitched, can be actuated comfortably without the expenditure of force. For showing the established state of tightening of the stabilizer 30, a display instrument 72 may additionally be provided.
In a dismantling step, it is possible to control the stabilizer 30 as a function of parameters, or in other words to vary the tightening force of the stabilizer 30 as a function of the varying group speed during travel. For that purpose, an electronic control unit 80 would have to be provided that detects signals 82 which represent the group speed and which evaluates these arriving signals 82 for trigger signals 84 for the electric motor 34 of the stabilizer 30.
It is also possible, for instance by detecting transverse accelerations or yawing moments occurring at the traction vehicle 10 and/or at the trailer, by the electronic control unit 80 during travel to design the described stabilizer 30 as an automatic group stabilizing system, in which the established tightening forces are regulated in accordance with these measured parameters. A conclusion about the friction conditions at that time between a trailer hitch 12 and a coupling element 18 can easily be drawn by way of the current consumed by the electric motor 34.
It is understood that refinements or additions to the exemplary embodiments described are conceivable without departing from the fundamental concept of the invention.
Stabilizers 30 actuatable by electric motor for instance also allow direct monitoring of the friction conditions between a trailer hitch 12 and a coupling element 18 and can be controlled or regulated as a function of the values ascertained. The prevailing friction conditions can for instance be ascertained by force sensors, which detect the incident shear forces between the brake levers 38 and the brake linings 32 secured to them, and send signals to the electronic control unit 80 to be evaluated. Temperature fluctuations can also be compensated for on the basis of temperature models stored in memory in the electronic control unit 80.
The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2007 059 900.7 | Dec 2007 | DE | national |
