Description

Field of the Invention

The present invention relates to a coupling device for coupling and decoupling a unit which is to be pulled by a vehicle. More specifically, the invention relates to a coupling device for coupling and decoupling a towable work tool which is to be pulled by a work vehicle, primarily a tractor. Background of the Invention

There are a number of different mechanical constructions which are arranged for coupling and decoupling of work tools (e.g. a wagon) which are to be pulled by a tractor. US2005095104 Al describes a mechanical coupling device for quick coupling and decoupling of a wagon to and from a tractor.

US 6390490 Bl describes a mechanical coupling device for quick coupling and decoupling between a work tool and a tractor, where part of the coupling device is mounted on the tractor and part of the coupling device is mounted on the work tool.

DE 4132889 Al shows a coupling device with electrical and hydraulic connection between a vehicle and a work tool.

These coupling devices provide mechanical coupling between a tractor and a work tool. In addition to the mechanical coupling between the tractor and the work tool that the tractor is to pull, it is, in easily most situations, most often necessary that the tractor's electrical system is connected to the electrical system of the work tool.

This connection is done manually in that the driver of the tractor steps out of the tractor and connects the tractor's electrical system to the work tool's electrical system by connecting an electric plug from the tractor to a corresponding electric plug on the work tool. This procedure can be extremely time-consuming. When grass for example is cut from grass fields, as much as up to 80 wagons can be filled during a work day. Each time a wagon is full, the wagon must be replaced, and it is required that the electrical system of the tractor is connected to the wagon's electrical system. Each replacement takes up to 3 minutes and since the driver of the tractor must get out of the tractor each time a wagon is to be replaced, the replacement procedure alone can take up to 4 hours during a day.

Therefore, it is desirable to provide a coupling device that is faster and less demanding to use.

Object of the Invention

It is the object of the present invention to indicate a coupling device for coupling and decoupling of a pullable unit and a work vehicle, which coupling device is quick and easy to use.

The object of the present invention is achieved with a coupling device as defined in claim 1. Preferable embodiments are defined in the subordinate claims, and are explained in the following description and illustrated in the accompanying figures. Since the coupling device comprises an arm, on which the first coupling unit is movably mounted, it is possible to connect a first coupling unit, which is movably mounted on a work tool (e.g. a wagon) to a second coupling unit on a work vehicle (e.g. a tractor). When the work tool is not connected to the work vehicle, the first coupling unit may be placed on the arm while the second coupling unit is mounted on the work vehicle. The arm can be arranged in different ways, but it is preferred that the arm reaches out in a direction such that the first coupling unit easily and without hindrance can be mounted on the arm, and that the first coupling unit subsequently can be connected with the second coupling unit. The coupling device according to the invention is arranged to couple and decouple a work tool to and from a work vehicle and the coupling device comprises a first coupling unit arranged to be hydraulically connected to a second coupling unit. The first coupling unit comprises means for connection arranged to establish hydraulic and electrical connection to the second coupling unit.

Thereby a coupling device is achieved that is quick and easy to use. Thus, the driver of e.g. a tractor saves time and effort when for example harvesting grass.

It is preferred that the fist coupling unit comprises connection means arranged to at the same time establish hydraulic and electrical connection to the second coupling unit. By creating a simultaneous connection of both the hydraulic and the electrical connection to the second coupling unit, it becomes possible to perform a very quick and effective coupling and decoupling of a work tool to a work vehicle.

It is advantageous that the first coupling unit comprises one or more plug connections that are arranged to be connected to corresponding plug connections on the second coupling unit by moving the first coupling unit relative to the second coupling unit. In this way, it is possible to provide a simple and robust coupling device.

It may be advantageous that the first coupling unit comprises one or more plug connections arranged to be connected to corresponding plug connections on the second coupling unit via linear movement of the first coupling unit relative to the second coupling unit. A linear movement makes it possible to provide a very simple and robust coupling device. It is advantageous that the coupling device comprises a hydraulic connection where hydraulic hoses are brought into a grip with each other.

It is possible that the first coupling unit comprises a first magnetic plate and that the second coupling unit comprises a second magnetic plate, and that the first magnetic plate is arranged to abut against the second magnetic plate and thus provide a positioning of the first coupling unit relative to the second coupling unit. Thus it is possible to position the first coupling unit in a desired way in relation to the second coupling unit. The two magnetic plates facilitate a very precise and quick positioning of the first coupling unit relative to the second coupling unit.

It is advantageous that a number of hydraulic hoses are connected to the first coupling unit and that the first coupling unit comprises a number of connection units for connection of hydraulic hoses and that one or more electrical cables are connected to the first coupling unit and that the first coupling unit comprises one or more electric contacts for connection of one or more electrical cables.

This construction ensures that the coupling device can be used for coupling of easily the majority of agricultural machines to tractors.

It is advantageous that the first coupling unit is arranged to grip into the second coupling unit such that the first coupling unit is coupled to and mechanically connected with the second coupling unit, and that the second coupling unit is mounted on the work vehicle.

It is thus ensured that the work vehicle can be used to decouple and couple the first coupling unit and the second coupling unit from and to each other.

It is advantageous that the coupling device comprises a

suspension arranged to be mounted on the work vehicle and that the second coupling unit is attached to the suspension. The suspension makes it possible to mount the second coupling unit on various types of work vehicles. The suspension can

advantageously comprise an oblong part arranged to be, largely, vertically suspended. The second coupling unit can

advantageously be mounted on the oblong part.

It is advantageous that the coupling device comprises at least one bar assembly that during use of the coupling device mainly extends vertically and that an arm is mounted on the bar assembly. Such a construction ensures that the first coupling unit can be mounted to the arm and that the work vehicle that is to be coupled to the work tool thus has easy access to the first coupling unit. The bar assembly may comprise one or more bars which can be parallel.

It is preferred that the coupling device comprises a locking device which is arranged to bring the first coupling unit into a grip with the second coupling unit by moving the first coupling unit relative to the second coupling unit.

Hereby, the locking device can ensure that the first coupling unit is brought into a grip with the second coupling device, such that a precise and complete connection between the first coupling unit and the second coupling unit is provided.

The locking device can advantageously be fully automatic, such that the driver of the work vehicle does not have to perform manual actions to ensure that a precise and complete coupling is established between the first coupling unit and the second coupling unit. The locking device can for example comprise a hydraulically driven locking arm, which presses the first coupling unit against the second coupling unit, such that a coupling is established between the first coupling unit and the second coupling unit.

Description of the Drawings

The invention will be described in the following while referring to the accompanying drawings, where

Fig. 1 shows a schematic illustration of a coupling device

according to the invention used to couple a tractor to a wagon,

Fig. 2 illustrates how a work tool is coupled to a tractor by using a coupling device according to the invention, Fig. 3 shows a schematic illustration of a coupling device

according to the invention,

Fig. 4 shows a schematic drawing of a plug connection unit to a coupling device according to the invention and Fig. 5 shows a schematic drawing of a second plug connection unit to a coupling device according to the invention.

Detailed description

As an introduction, it should be noted that the accompanying drawing only illustrates non-limiting embodiments. A number of other embodiments will be possible within the scope of the present invention. In the following, corresponding or identical elements in the different embodiments will be referred to by the same reference numbers.

Fig. 1 is a schematic illustration of a coupling device 2 according to the invention. The coupling device 2 is used to couple a tractor 4 to a wagon 6. The wagon 6 is mechanically coupled to the tractor 4. The wagon 6 is additionally hydraulically connected to the tractor's hydraulic system via hydraulic hoses 24 and electrically connected to the tractor's electrical system via electrical cables 26.

The coupling device 2 comprises a first coupling unit, which is arranged to establish hydraulic and electrical connection to the second coupling unit, which is illustrated in Figures 2-4.

Fig. 2 shows how a work tool 6 is connected to a tractor 4 with the aid of a coupling device 2 according to the invention. Fig 2 a) shows a coupling device 2 according to the invention. The coupling device 2 consists of a first coupling unit 12 and a second coupling unit 14. The first coupling unit 12 hangs from an slightly askew arm 18 mounted on a vertically oriented bar assembly 20. The bar assembly 20 is attached to a bracket 22, which is a part of the work tool 6. The work tool 6 can for example be a wagon or a forage harvester.

A foot 8 is mounted on the bracket 22, and the foot 8 rests on the underlayer 42. The first coupling unit 12 is hydraulically connected to the work tool 6 via hydraulic hoses 24 and electrically connected to the work tool 6 via electrical cables 26. A pulling device 10 is arranged at the tip of the bracket 22. This pulling device 10 can be coupled mechanically to a

corresponding pulling device (not shown) mounted on the tractor On the rearmost part of the tractor 4, a suspension 16 is mounted on which the second coupling unit 14 is mounted. To connect the work tool 6 to the tractor 2, the tractor 2 shall reverse up to the work tool 6 as shown in Fig. 2 b). In Fig. 2 b) the suspension is moved higher up than shown in Fig. 2 a). The second coupling unit 14 is not yet put into a grip with the first coupling unit 12. When the second coupling unit 14 is displaced slightly further in a vertical direction, the second coupling unit 14 becomes capable of lifting the first coupling unit 12 free from the arm 18 on which the first coupling unit 12 is mounted. The second coupling unit 14 comprises a holding device 46 and a locking arm 44 rotatably mounted on the holding device 46.

In Fig. 2 c) the second coupling unit 14 is brought into a grip with the first coupling unit 12. The first coupling unit 12 is, by rotation of the locking arm 44 in a clockwise direction, brought into a grip with the holding device 46 of the second coupling unit 14. This rotation is provided by activating a hydraulically driven piston (see Fig 3), which is arranged to provide the desired rotation of the locking arm 18.

In Fig. 2 d) the suspension 16 is displaced downwards in a vertical direction and the pulling device 10 is mechanically coupled to a corresponding pulling device on the tractor 4. The tractor 4 is hydraulically connected to the work tool 6 via hydraulic hoses 24 and electrically connected to the work tool 6 via electrical cables 26. The foot 8 on the bracket 22 is raised above the underlayer 42. This can be done by moving the suspension 16 upwards in a vertical direction, as the pulling device 10 is mechanically coupled to a corresponding pulling device on the suspension 16.

Fig. 3 is a schematic illustration of the coupling device 2 shown in Fig. 2. The work tool 6 is provided with a bracket 22, which is supported by a foot 8. A vertically mounted bar assembly 20 is attached to the upper side of the bracket 22 and an arm 18 extends at an angle upwards from the distant end of the bar device 20. A first coupling unit 12 is mounted on the free end of the arm 18. The first coupling unit 12 comprises a hydraulic coupling unit 38 with three studs, which fit down into and can be brought into a grip with three corresponding cylindrical holes in a second hydraulic coupling unit 40 from a second coupling unit 14. An electrical cable 26 extends from the work tool 6 to the first coupling unit, where an electrical connection is established between the work tool 6 and the first coupling unit 12. Two hydraulic hoses 24 extend from the work tool 6 to the first coupling unit and connect the work tool 6 with the first coupling unit 12 hydraulically.

The second coupling unit 14 comprises a holding device 46 and a locking arm 44 rotatably mounted on the holding device 46. A hydraulically driven piston 48 connects the lowest free end of the holding device and the lowest free end of the locking arm. When the first coupling unit 12 is moved down into the second coupling device 14 and the hydraulically driven piston 48 is activated, the locking arm 44 is rotated around its axis of rotation 50. Hereby, the hydraulic coupling unit 38 with the three studs is pushed in a grip with three corresponding cylindrical holes in the second hydraulic coupling unit 40 from a second coupling unit 14. Fig. 4 shows a schematic illustration of a plug connection unit for a coupling device according to the invention. The plug

connection unit consists of a first part with a hydraulic coupling unit 38 with three studs and an electrical plug connection 30.

In Fig. 4 a) the first part of the plug connection unit and the second part are not connected to each other. In Fig. 4 b) the first part of the plug connection unit and the second part are connected to each other. The hydraulic coupling unit 38 with the three studs and the electrical plug connection 30 are brought into a grip with the corresponding hydraulic coupling unit 40 with the three studs and the electrical plug connection 28,

respectively.

Fig. 5 shows a possible embodiment of a plug connection unit according to the invention. The plug connection unit comprises the same elements as the plug connection unit shown in Fig. 4. In Fig. 5 a) the plug connection unit's first part and second part are not connected, whereas the plug connection unit's first part and second part are connected to each other in Fig. 5 b). The hydraulic coupling unit 38 comprising three studs and the electrical plug connection 30 are in a grip with the corresponding hydraulic coupling unit 40 comprising three cylindrical studs and the electric plug connection 28, respectively.

Additionally, the first part comprises a first magnetic plate 32, which is arranged to abut against a second corresponding magnetic plate 34. As the two magnetic plates shall be used to position the two parts of the plug connection unit in relation to each other, the two sides of the magnets that are to be brought in contact with each other should be able to attract each other. Therefore the two sides should have different polarity (i.e. south pole turned towards north pole).

The second magnetic plate 34 is attached to the plug connection unit's second part, which consists of a hydraulic coupling unit 40 with three cylindrical studs and an electric plug connection 28.

Thus, it is possible to use a plug connection unit that does not comprise magnetic plates to provide a precise positioning of the two parts in relation to each other. But it should be emphasised that a solution without magnetic plates is usable and functional.

Reference Numbers

2 Coupling Device

4 Work Vehicle

6 Work Tool

8 Foot

10 Pulling Device

12 First Coupling Unit

14 Second Coupling Unit

16 Suspension

18 Arm

20 Bar Assembly

22 Bracket

24 Hydraulic Hoses

26 Electrical Cable

28 Plug Connection

30 Plug Connection

32 First Magnetic Plate

34 Second Magnetic Plate

36 Locking Device

38 Hydraulic Coupling Unit

40 Hydraulic Coupling Unit

42 Underlayer

44 Locking Arm

46 Holding Device

48 Hydraulically Driven Piston

50 Axis