DE102018117560A1 - Device for torque transmission - Google Patents

Abstract

The invention relates to a method or a device (31) for transmitting torque from a drive unit (30) to a working device (41), in particular from a tractor to a working device (41), via a transmission (39) with a torque switch (38 ), for changing the transmission ratio of the transmission (39) operable by a drive shaft (40) in dependence on a torque difference between the drive shaft (40) and a transmission input shaft (45) of the transmission (39), wherein the drive shaft (40) of the drive unit (40) 30) is drivable. The object to provide a corresponding device (31), which is designed to be as simple and robust and prevents damage to the implement (41) during normal operation by transmitting too large torque from the drive unit (30) and / or optimal circuit of the transmission (39) is achieved in that the torque switch (38) has a device for generating a hydraulic output signal, or that the torque switch (38) at least one defined torque, a hydraulic output signal is generated and to the transmission (39 ) is sent.

Description

The invention relates to a device for transmitting torque from a drive unit to a working device, in particular from a tractor to a working device, via a transmission with a torque switch, for changing the transmission ratio of the drive operable by a drive shaft in response to a torque difference between the drive shaft and a transmission input shaft Transmission, wherein the drive shaft is driven by the drive unit, and a method for operating a working device, wherein from a drive unit, in particular a tractor, a torque is transmitted to the implement, the implement has a transmission, which is operated by a drive shaft, and the transmission is automatically switched by a torque switch as a function of the torque of the drive shaft.

Drives powered implements are used in many parts of the economy, but especially in agriculture, in the form of tractors or similar traction towed and driven implements such as harrows, plows, and others. Work implements are understood to mean all working machines or driven devices, in particular in the agricultural sector, which absorb energy in the form of mechanical work and serve to carry out a particular work or a specific work step and which must be supplied with torque by a drive unit. Drive units are understood to mean power machines which deliver mechanical energy and are suitable for driving implements. Drive units thus include, for example, internal combustion engines together with drive trains. It can often, but not always the implement are moved in the operated state of the drive unit, bar mowers, for example, find while driving the tractor application. However, this is not advantageous in all drive units, for example in circular saws or wood splitters, which are supplied with torque in the stationary state of tractors. In most cases, the implement can be separated from the drive unit, or a drive unit can optionally operate different implements simultaneously or in succession. In general, the transmission of torque via a PTO or a PTO to the drive unit, to which the implement is connected.

The torque at which the implement is operated should not exceed a certain maximum value in order to avoid damaging the mechanics of the implement and the PTO. For this purpose it makes sense to provide a gearbox in the implement. Often, a torque switch is provided for this, which measures a torque of a drive shaft and a drive operable by the drive shaft is switched on the basis of this measurement value to prevent exceeding the maximum value.

The DE 28 05 619 A1 shows a vehicle having an overload protection device that decouples a drive shaft from a device shaft in the presence of excessive torque. This effectively prevents the overload of the system. The disadvantage, however, is that it automatically comes to a freewheel during decoupling and thereby to an interruption of the torque supply of the device, which is driven by the device shaft. This will temporarily disable this device.

From the DE 10 2012 212 936 A1 Controllers are known which serve to control a transmission of a drive train, wherein measured by means of a vehicle computer sensor, the torque of an input shaft and depending on the measured torque, the transmission is switched, so that the torque does not exceed a threshold. However, devices of this type are susceptible to interference and error.

In the DE 10 2013 110 315 A1 Drive units are described as tractors, which transmit torque via a PTO to a working device, wherein a PTO gear is switched depending on at least one operating parameter. The type of sensor or signal transmission is not described in detail.

The object of the invention is thus to provide a device for transmitting torque from a drive unit to a working device or a method for operating a working device, which is designed to be as simple and robust and damage to the implement during normal operation by transferring a too large torque of prevents the drive unit and / or during normal operation allows an optimal circuit of the transmission.

This object is achieved in that the torque switch has a device for generating a hydraulic output signal, or that the torque switch at least one defined torque, a hydraulic output signal is generated and sent to the transmission.

By generating a hydraulic output signal or by sending Hydraulic output signals is produced in a very simple way a signal transmission between torque switch and gearbox. Since hydraulic systems are very robust and durable, and so the use of electrical system and structurally complex and error-prone mechanical devices is avoided, as long as possible life of the implement can be ensured. It also eliminates the sometimes complicated supply of electricity. Since most drive units anyway have a hydraulic interface for providing hydraulic power, the use of a hydraulic system is particularly advantageous because the hydraulic force so usually does not have to be generated by the implement itself. The integration of the switching function in the implement also makes the system very inexpensive and fast.

In many known systems with comparable simplicity and reduced possible connections between drive unit and implement often only a manual transmission of the transmission is possible by a person performing the device structure, which must be done directly on the implement. This is unfavorable, since usually only one person operates the work structure and this is usually busy with the drive unit, for example, in the case of a tractor directs this. As a result, this must leave its position on the implement to make the circuit directly and then can continue his work. This is not necessary in the described devices or methods and the work must therefore not be interrupted.

Optimal switching behavior can also be achieved by such a device or such a method, since the transmission circuit takes place automatically and is determined by the torque of the drive shaft, which represents the optimum parameter for determining the switching time.

In a preferred embodiment of the device, the transmission is exclusively switchable by the torque switch. The independence of the drive unit on the one hand simplifies the construction of the device, on the other hand, a disadvantageous circuit of the transmission is prevented. The person operating the drive unit can no longer cause, by actively shifting, those transmission states that are unfavorable to the implement as they unnecessarily burden them. At the same time, the operator no longer has to worry about shifting the transmission and can focus on other aspects of the work, which is a relief for them.

At the same time the implement does not need to be additionally connected to the drive unit, since there is no need for transmission of switching signals. As a result, the implement can also be used in simple drive units, which do not have complex logic for switching the transmission of the implement. In addition, interface problems are prevented in the presence of such logic.

If the transmission is designed as a power shift, so this improves the performance of the implement, since the work does not have to be interrupted during the switching process. In particular, two-stage powershift transmission are easy to perform and often sufficient to ensure a good function.

In order to prevent unnecessary constant switching of the transmission, when the torque of the drive shaft is moved between values just above and just below the threshold at which switching occurs, it is advantageous to provide a torque hysteresis. This is understood to mean a switching behavior in which the threshold value for switching in one direction and the threshold value for switching in the other direction are different. If no two-stage transmission is used, but a multi-stage transmission, this refers to the transition between two successive stages. Different hystereses can be provided for different step transitions.

The form in which the generated signals affect the transmission may vary depending on the embodiment. It may be useful, for example, to emit a signal in an embodiment with two signals and a two-stage transmission until a circuit is to be produced. If this occurs, the signal is terminated and a second signal started to emit. If the circuit is completed, the second signal remains until a switching operation is desired again, which is indicated by changing to the first signal. Another possibility provides that the signals represent only short sequences, which are terminated shortly after the desired switching operation or possibly before it.

In a preferred embodiment, the torque switch has a rotary valve with a first shaft, which is preferably in communication with the drive shaft and with a second shaft, which is preferably in communication with the transmission, wherein they have a common axis of rotation. The waves may be at least partially concentric with each other or arranged one behind the other, or even touching only one end face, anyway, they are rotatably mounted against each other and coupled via a first spring.

Preferably, the first shaft has at least a first hydraulic inlet channel and a first hydraulic return channel, each having at least one channel opening, and the second shaft at least a second hydraulic inlet channel and a second hydraulic return channel, each having at least one channel opening. Depending on the embodiment, several channels may be provided, especially if the transmission has more than two stages. It is essential that the first inlet channel and the second inlet channel in at least a first rotational position of the two shafts are fluidly connected to each other via the channel openings, while the first return channel and the second return channel are not fluidly connected in this position on the channel openings, so separated, and the first return channel and the second return channel are fluidly connected to one another via their channel openings in at least one second rotational position of the two shafts, while the first inlet channel and the second inlet channel are not flow-connected in this position via their channel openings, ie are separated. Depending on the embodiment, the channel openings can lie either on the inner or outer jacket of the shafts, if the shafts run at least partially into one another, or can also lie on the mutually facing end faces. The openings do not necessarily have to be round, they may also have, for example, an elongated shape in order to increase the rotational range with respect to the corrugations with respect to one another, in which the inlet channels or return channels are flow-connected. Optionally, the waves in the region near the other wave can change their shape or diameter. For example, they may be reinforced or have flange-like ends to provide more space for the inlet channels and return channels, or their openings. For the preparation of the inlet channels and return channels is an exemplary, cheap and simple production form drilling the channels in the waves.

By using such a torque switch, the torque difference of the torques of the first shaft and the torques of the second shaft can cause a twisting of the two shafts against each other. The degree of rotation thus reflects the magnitude of the torque difference again. If a torque difference which is so great that the shafts assume the described first rotational position relative to one another, then a hydraulic flow of the actuating fluid can take place via at least one first and second inlet channel, while this is not the case via at least one first and second return channel , If the torque changes in such a way that the shafts move into the second rotational position relative to one another, a hydraulic flow of the actuating fluid can take place via at least one first and second return channel, while this is not the case via at least one first and second inlet channel. As a result, at least two different signals can be generated depending on the torque acting. The same applies to a method in which it comes to the connection of pressure sources or pressure sinks with hydraulic control lines of the transmission, depending on the torque of the drive shaft.

In order to generate a hydraulic signal, a pressure source or pressure sink can be provided in the torque switch itself, which automatically increases or decreases the pressure of the actuating fluid for the signal, but it could also be a corresponding pressure source or sink elsewhere in the implement be provided. However, it is particularly advantageous if the pressure source or pressure sink is located in the drive unit and is acted upon by hydraulic connections of these with the first hydraulic inlet channel or first hydraulic return channel of the torque switch with at least two different pressure levels of the actuating fluid. In the case of more than one inlet channel and one return channel, it may also be advantageous to supply the different inlet channels or return channels with different hydraulic pressure intensities, or even provide a plurality of pressure sources or pressure sinks, which may differ in the size of the pressure or negative pressure.

In order to fix a defined rotational position of the first and second shaft until the action of defined minimum torques, locking bodies may be provided in an advantageous embodiment which are brought into a locking position in at least one rotational position of the two rotatable shafts. These should generally be designed so that the rotational position within a certain first minimum torque in one direction and a second minimum torque in the other direction between the waves is not changed. Most of the first minimum torque and second minimum torque should be chosen so that they can occur during the intended use of the implement. Optionally, however, the locking body may also be intended to prevent excessive rotation of the shafts to one another and be releasable again only in one direction of rotation. Accordingly, depending on the application, the first minimum torque and the second minimum torque can be selected symmetrically, so that both minimum torques the have the same amount and differ only in the direction of rotation, or be chosen asymmetrically. The same can also be achieved if a method is used in which a locking body is brought in at least one rotational position of the two rotatable shafts to each other in a locking position.

The execution of such a locking body may provide that the locking body is seated on a shaft and is displaced in a recess provided for this purpose in the other shaft in a specific rotational position. As a result, an easy to construct embodiment is found, which defines a rotational position within a certain torque band between the first minimum torque and the second minimum torque. The locking body can preferably be moved by a spring into the recess. In this case, the torque band of the shape of the Arretierungskörpers, the shape and especially the depth of the recess and other factors, such as the characteristic of the optionally provided spring determined.

The characteristic of the first spring significantly determines the rotational behavior of the two shafts to each other. Accordingly, it is advantageous to provide at least one adjusting screw in order to be able to set the tensioning force of the first spring accurately. These adjustment screws can each be attached to the mechanical stops and exert by twisting an additional force on the first spring. Thus, the sensitivity and the travel can be adjusted.

In order to prevent over-rotation of the shafts relative to one another, at least one stop for limiting the rotational movement of the first shaft and the second shaft relative to one another can also be provided in an advantageous embodiment. For example, such stops in the form of projecting fingers can be provided directly on the first spring or on its suspension. This represents a very simple and cost-effective variant, so as to represent a maximum twist. Are the waves in a position in which at least one stop prevents further rotation in one direction, so no minimum torque must be applied so that the waves in the other direction can rotate each other - provided that the rotational position is not in addition to any existing Locking body set.

It is advantageous if, in a rotational position in which at least one locking body is in a locking position, at least two inlet channels or return channels running in different waves are flow-connected. By fixing the first shaft and second shaft in a rotational position, when at least one channel is flow-connected, it is ensured that a flow of the actuating fluid through the corresponding channels in this rotational position for a long time is present and thus a sufficiently long and clear signal to the transmission can be passed on. In addition, this has the consequence that the signal persists until a minimum torque acts on the locking body and this moves from its locking position.

It is particularly advantageous if a locking body can assume two locking positions and, when a first locking position is taken, the first inlet channel and the second inlet channel are flow-connected to each other via their channel openings, while the first return channel and the second return channel are not flow-connected in this locking position via their channel openings, as well when the second locking position is taken up, the first return channel and the second return channel are flow-connected to one another via their channel openings, while the first inlet channel and the second inlet channel are not flow-connected in this locking position via their channel openings. The same can also be achieved if a method is used in which, at two torques, on the one hand, a connection of a pressure source to a control line and a separation of a control line from a pressure sink, and, on the other hand, a separation of a control line from a pressure source and a connection a pressure sink comes with a control line. These embodiments or these methods are particularly advantageous in the case of two-stage transmissions, since it is thus possible to ensure in a reduced embodiment that at least two different switching signals are generated by the torque switch in two different rotational positions. It is particularly advantageous here if the switching signals are assigned to different hydraulic pressure levels of the actuating fluid, in which actuators of clutches of the transmission are actuated via hydraulic control lines. These are unique shift signals for the transmission to change the gear ratio. It is particularly advantageous in this sense, when the rotational behavior of the shafts to each other is chosen so that the minimum torque that must be applied so that the locking body leaves the first locking position toward the second locking position corresponds to the torque at which a shift of the transmission is desired , Thus, when such a torque of the Arretierungskörper leaves the first locking position, the flow-connected inlet channels upstream are rotationally displaced so that they are no longer flow-connected, and by the Flow connection to the control line emitted hydraulic signal is terminated. The first and second shaft rotate by the effect of torque against each other further in the direction that dictates the torque. As a rule, this torque is composed of the difference between the external torques which are transmitted to the first and second shafts by the drive shaft or the transmission and, in particular, counteracts the spring torque exerted by the first spring. The waves continue to rotate until the locking body reaches the second locking position, and is pushed into this. As a result, the return channels are flow-connected, which generate a preferably opposite signal with respect to the described signal of the first rotational position. This can be triggered in the transmission, a switching operation. Upon decreasing the torque, this second rotational position is maintained by the locking device until the torque in the opposite direction exceeds a minimum torque, so that the locking body releases from its second locking position and the shafts rotate again toward each other in the first rotational position. The described first and second rotational position can be so close to each other that results in a change of the rotational position, a direct transition from the flow connection of the inlet channels to the flow connection of the return channels. This is achieved by the angular difference between the described rotational positions depending on the size of the channel openings only a few degrees, for example 45 °. However, it may also be advantageous to provide a distance of more than a few degrees and thus clearly finish a signal before the other signal starts to be generated.

A similar system can also be used in multi-stage transmissions. In such cases, there would be a plurality of locking positions for a locking body, or more locking bodies would be provided with different locking positions, so that more than two rotational positions can be determined by the locking body. In each rotational position in which at least one locking body is in a locking position, at least two inlet channels or return channels running in different waves are flow-connected.

A variant embodiment is also possible, in which a locking body can assume at least one locking position in a rotational position between the first and the second rotational position. In this intermediate rotary position, preferably neither inlet channels nor return channels are flow-connected, whereby no output signal is generated. This may be advantageous if the device is designed such that the transmission does not switch in this state, while it switches one level higher or lower upon receipt of one of the two signals. Although it may be advantageous to fluidly connect inlet channels or return channels also in this intermediate position, however, even the guidance of only a first and second inlet channel and only a first and second return channel may be sufficient to obtain a device having a three-stage or can switch even more multi-stage transmission.

• 1 eine erfindungsgemäße Vorrichtung in einer schematischen Darstellung;
• 2 einen Drehmomentschalter einer erfindungsgemäßen Vorrichtung in einer ersten Drehstellung in einem Schnitt gemäß einer Linie I-I in 3;
• 3 den Drehmomentschalter in einem Schnitt gemäß der Linie III-III in 2;
• 4 diesen Drehmomentschalter in einer Zwischendrehstellung in einem Schnitt analog zu 2;
• 5 den Drehmomentschalter in einer zweiten Drehstellung in einem Schnitt gemäß der Linie V-V in 5;
• 6 den Drehmomentschalter in einem Schnitt gemäß der Linie VI-VI in 5.

In the following, the present invention will be explained in more detail with reference to the embodiment variants shown in the non-limiting figures. Show it:

• 1 a device according to the invention in a schematic representation;
• 2 a torque switch of a device according to the invention in a first rotational position in a section along a line I - I in 3 ;
• 3 the torque switch in a section along the line III - III in 2 ;
• 4 this torque switch in an intermediate rotational position in a section analogous to 2 ;
• 5 the torque switch in a second rotational position in a section along the line V - V in 5 ;
• 6 the torque switch in a section along the line VI - VI in 5 ,

1 shows a device according to the invention 31 for transmitting torque from a drive unit 30 to a working device 41 via a propeller shaft 32 , The drive unit 30 has an internal combustion engine 33 on which via a clutch 34 with a gear 35 connected is. This gear 35 represents the main gearbox of the drive unit 30 is, among other things, with a PTO 37 via a PTO clutch 36 connected. This PTO 37 is about the joint shaft 32 with a drive shaft 40 the work unit 31 connected. This is how the drive torque is applied to the torque switch 38 transfer. The torque switch 38 directs the drive torque of the drive unit 30 via a transmission input shaft ( 45 ) continue to a two-stage powershift transmission 39 whose transmission output 39a the implement 41 the device 31 drives.

The gear 39 is designed for example as a power shift transmission and has in the exemplary embodiment two transmission stages S1 . S2 on, which via a first clutch 42 and a second clutch 43 be switched.

The first clutch 42 and the second clutch 43 are generated by the hydraulic output signal generating torque switch 38 automatically depending on the drive torque of the drive shaft 40 switched, in each case one of the two clutches 42 . 43 engaged and the other clutch 43 . 42 is disconnected. In the idle state, ie in the depressurized state, is the first clutch 42 closed and the second clutch 43 open. About the torque switch 38 and the hydraulic control lines 42b . 43b becomes the respective actuator 42a . 43a the first clutch 42 or second clutch 43 with a pressure source 50 or pressure sink 51 connected.

In the 2 to 6 is an embodiment of a torque switch 38 shown, which has a first inlet channel 6 , a second inlet channel 11 , as well as a first return channel 7 as well as a second return channel 12 having. The first inlet channel 6 and the first return channel 7 extend inside a first shaft 13 and each have a channel opening 6a . 7a on the outer coat 13a the first wave 13 on, the second inlet channel 11 and the second return channel 12 run inside a second shaft 14 and each have a channel opening 11a . 12a on the inner coat 14a the second wave 14 on. The first wave 13 is in drive connection with a PTO shaft 32 the working machine 30 , the second wave 14 stands with a gearbox 39 in connection, like out 1 is apparent. The PTO 32 transmits drive torque to the first shaft 13 , The first wave 13 runs partly within the second wave 14 , whereby these are mutually rotatable. A first spring 4 has a first end element 15 and a second end element 5 on, wherein the first end element 15 with the first wave 13 and the second end element 5 with the second wave 14 is firmly connected. Along a guide in which the first spring 4 are moved, are on the first wave 13 and at the second wave 14 each end stops 8th provided the movement of the first spring 4 limit.

In the in 2 and 3 shown first rotational position of the waves 13 . 14 lie the channel openings 7a . 12a of the first return channel 7 and the second return channel 12 covering each other, so that these channels are fluidly connected, while the channel openings 6a . 11a of the first inlet channel 6 and the second inlet channel 11 are twisted against each other, bringing these feed channels 6 . 11 are not fluidly connected. In the illustrated first rotational position so can a hydraulic flow 20 take place of the actuating fluid. In this position are the actuators 42a . 43a the clutches 42 . 43 with the pressure sink 51 connected. In this configuration, a first gear ratio is set. The change of the gear ratio is load-dependent. Furthermore, a locking unit is provided, this consists of an example cylindrical locking body 1 which is in a radial bore, in the first shaft 13 to be led. The locking body 1 is due to the bias of a second spring formed for example by a coil spring 2 against the second wave 14 pressed. The second wave 14 has recesses 3a . 3b related to the geometry of the locking body 1 are matched, the location of each recess 3a . 3b a defined rotational position of the two shafts 13 . 14 assigned. In the in 2 illustrated first rotational position thereby locks the locking body 1 in the first recess 3a and in an in 4 shown second rotational position in the second recess 3b one. Every recess 3a . 3b has lateral ramps 3c . 3d on. The slope of the ramps 3c . 3d and the second spring 2 are tuned so that at defined torque of the drive shaft 40 the locking body 1 is released. Upon reaching the defined torque of the locking body 1 against the force of the second spring 2 through the side ramps 3c . 3d from the recess 3a pressed.

In 4 an intermediate rotational position is shown, in which the in 2 shown hydraulic flow 20 is no longer possible because at the rotation of the first wave 13 in relation to the second wave 14 the flow of the actuating fluid from the coupling to the tank is interrupted. At this stage, the first spring 4 pressed together. As a result, due to the further rotation of the first shaft 13 , the circumferential force on the first spring 4 to. The first spring 4 must be able to store that mechanical energy to ensure a downshift with decreasing drive torque, which comes about due to the changed gear ratio. The spring force takes at the end of this compression phase their maximum force and the Arretierungsköper 1 snaps into another recess 3 one. There is force equilibrium between the circumferential force and the spring force (plus the inertial force of the shaft 13 to the shaft 13 in the Arretierungslage 3b to accelerate).

In 5 and 6 has the Arretierungsköper 1 in the further recess 3 emotional. Another twist of the first wave 13 on the one hand by the locking itself and on the other by the preloaded first spring 4 prevented. In this rotational position, the two channel openings overlap 7a . 12a of the first return channel 7 and the second return channel 12 , Now, a hydraulic reflux 20 the control lines 42b . 43b to the pressure sink 51 occur. By the pressure reduction in the control lines 42b . 43b is in the transmission 39 for pressure build-up and a Gear ratio change completed. Within the further recess 3 is the locking body 1 able to absorb changes in drive torque. However, the drive torque falls below a minimum torque of the further recess 3 , the transition is initiated in an intermediate rotational position. With appropriate design of the spring stiffness and the recesses 3 can be a hysteresis behavior with respect to drive torque accomplish.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 2805619 A1 [0004]
• DE 102012212936 A1 [0005]
• DE 102013110315 A1 [0006]

Claims (17)

Device (31) for transmitting torque from a drive unit (30) to a working device (41), in particular from a tractor to a working device (41), via a transmission (39) with a torque switch (38), for changing the transmission ratio of a Drive shaft (40) operable transmission (39) in response to a torque difference between the drive shaft (40) and a transmission input shaft (45) of the transmission (39), wherein the drive shaft (40) of the drive unit (30) is driven, characterized in that the torque switch (38) comprises means for generating a hydraulic output signal. Device (31) according to Claim 1 , characterized in that the transmission (39) exclusively by the torque switch (38), independently of the drive shaft (40) driving the drive unit (30) is switchable. Device (31) according to Claim 1 or 2 , characterized in that the transmission (39) is a, preferably two-stage, powershift transmission. Device (31) one of Claims 1 to 3 , characterized in that the switching behavior of the torque switch (38) has a torque hysteresis. Device (31) according to one of Claims 1 to 4 , characterized in that the torque switch (38) has a rotary valve with a first shaft (13) and a second shaft (14), which have a common axis of rotation (38a) and rotatably supported relative to each other and via a first spring (4 ) are coupled. Device (31) according to Claim 5 , characterized in that the first shaft (13) at least a first hydraulic inlet channel (6) and a first hydraulic return channel (7), each having at least one channel opening (6a, 7a), and the second shaft (14) at least one second inlet channel (11) and a second return channel (12) each having at least one channel opening (11a, 12a), wherein the first inlet channel (6) and the second inlet channel (11) in at least a first rotational position of the two shafts (13, 14) relative to each other via the channel openings (6a, 11a) are flow-connected, while the first return channel (7) and the second return channel (12) in this position via the channel openings (7a, 12a) are not fluidly connected, and that the first return channel (7) and the second return channel (12) in at least a second rotational position of the two shafts (13,14) are fluidly connected to each other via their channel openings, w the first inlet conduit (6) and the second inlet conduit (11) are separated in this position about their channel openings each other while. Device (31) according to Claim 6 , characterized in that at least one first inlet channel (6) with at least one pressure sink (51) is connectable and at least a first return channel (7) with at least one pressure source (50) is connectable. Device (31) according to Claim 6 or 7 , characterized in that at least the first shaft (13) or the second shaft (14) of the torque switch (38) at least one Arretierungskörper (1), in at least one rotational position of the two rotatable shafts (13,14) to each other in a locking position can be brought. Device (31) according to Claim 8 , characterized in that the at least one locking body (1) - preferably by a second spring (2) - in at least one locking position in a recess (3a, 3b) of the other shaft (13, 14) is displaced. Device (31) according to one of Claims 6 to 9 , characterized in that the torque switch (38) comprises at least one adjusting screw for adjusting the biasing force of the first spring (4). Device (31) according to one of Claims 6 to 10 , characterized in that the torque switch (38) at least one stop (8, 18) for limiting the rotational movement of the first shaft (13) and the second shaft (14) relative to each other. Device (31) according to one of Claims 9 to 11 , characterized in that at least one in the first shaft (13) extending first inlet channel (6) and at least one in the second shaft (14) extending second inlet channel (11) or at least one in the first shaft (13) extending first return channel ( 7) and at least one in the second shaft (14) extending second return channel (12) are fluidly connected when at least one locking body (1) is in a locking position. Device (31) according to Claim 12 , characterized in that a locking body (1) can assume at least two locking positions and that when taking a first locking position of the first inlet channel (6) and the second inlet channel (11) with each other via the channel openings (6a, 11a) are flow-connected, while the first Return channel (7) and the second return channel (12) in this locking position on the channel openings (7a, 12a) not are fluidly connected, and that when the second locking position of the first return channel (7) and the second return channel (12) with each other via the channel openings (7a, 12a) are flow-connected, while the first inlet channel (6) and the second inlet channel (11) in this Arretierungsposition over the channel openings (6a, 11a) are not fluidly connected. Device (31) according to one of Claims 9 to 13 , characterized in that the locking body (1) in the first locking position in a first recess (3a) and in the second locking position in a second recess (3b) is einlenkbar. Method for operating a working device (41), wherein a torque is transmitted to the working device (31) by a drive unit (30), in particular a towing vehicle, the working device (41) has a gear (39) which is driven by a drive shaft (40 ) is operated, and the transmission (39) by a torque switch (38) depending on the torque of the drive shaft (40) is independently switched, characterized in that the torque switch (38) at least one defined torque, a hydraulic output signal is generated and at the transmission (39) is sent. Method according to Claim 15 characterized in that at least a first torque of the drive shaft (40) a flow connection between at least one pressure source (50) and at least one hydraulic control line (42b, 43b) of the transmission (39) is produced and the flow connection between at least one pressure sink (51 ) and the hydraulic control line (42b, 43b) is interrupted. Method according to Claim 15 or 16 characterized in that at least one defined second torque of the drive shaft (40) a flow connection between at least one pressure sink (51) and at least one hydraulic control line (42b, 43b) of the transmission (39) is produced and the flow connection between at least one pressure source ( 50) and the hydraulic control line (42b, 43b) is interrupted.

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