EP1362958A2 - Vehicle provided with a working tool as well as a control system for a working tool with a parallel guidance - Google Patents

Abstract

Agricultural or industrial vehicle (10) has a work tool (30) with a lift drive (25) and an additional drive (35) for controlling rotation of the work tool at the free end (21) of the tool mounting unit (20). Said additional drive is independent of the lifting force applied to the lifting drive. The invention also relates to a corresponding control unit for work tool of a agricultural or industrial vehicle.

Description

The invention relates to a vehicle with a work tool, in which the Working tool connected to the vehicle via a fastening device is in which the fastening device is rotatable at one end is connected to the vehicle in which the fastening device on its other, free end is rotatably connected to the work tool, in which a lifting drive is provided which rotates the fastening device around it end connected to the vehicle upwards or downwards swivels and so raises or lowers the work tool a control device is provided for the position of the work tool which control device is a parallel guide device for the work tool having. The invention also relates to a control device for such a vehicle with a work tool.

There are a variety of vehicle types that are equipped with work tools are which in turn are to be conveyed upwards and downwards. Examples are lifting platforms, excavator buckets, pallet forks, work stands, scoop containers etc. These work tools are arranged on a fastening device, about a swing arm. If this is raised, it lifts it on hers End working tool with. But this also has to be relatively moving can also be used to lift the contents of an excavator shovel to be able to specifically dump it.

It is often desired that these work tools, despite their Height adjustability automatically a predetermined, in particular horizontal Can maintain the angular position. For example with pallet forks or This is immediately obvious to scooping containers.

If you take this example of a pallet fork or a scoop, so should the work tool be a specific product, for example one on the Pallet fork stacked pallet with goods or in the scoops one Lift liquid or a viscous mass. This lifting is done by the fastening device with its end connected to the vehicle is swung up. Now it has to be ensured by a parallel guide be that the work tool at the other end of the fastener pivots in the opposite direction, so that the pallet fork, the scoop or the other work tool afterwards exactly horizontal stand and not lose the products stacked on it or contained in it.

It should also be taken into account that this position is then at Movement of the vehicle is maintained.

Parallel guidance devices are provided for this purpose. Known are mechanical means such as rods, ropes or chains, but they are are subject to heavy wear due to the forced mechanics.

An example of such a forced mechanism is given in DE 100 12 389 A1. It is a so-called Z control or Z kinematics. Through mechanical, cross-over in a Z-shape and articulated together Lever ensures that a work tool is guided in parallel becomes. A single lifting cylinder also serves to lift the work tool and for the corresponding tracking to keep the the same. With such a concept, parallel guidance can certainly be ensured as the forced mechanics work practically tolerance-free. For construction machines this principle is well proven. However, a very high one arises Wear and considerable forces are also used, which lead to corresponding Losses and thus lead to additional energy consumption.

As an alternative, for example, in DE 28 34 480 C2 or DE 84 16 495 U1 hydraulic parallel guidance devices have been proposed. By exchanging the hydraulic fluids accordingly, the Lifting the tools at the same time ensure that they are horizontal stand or move in a horizontal position.

In a similar form, DE 40 09 163 A1 describes an excavator with an automatic one Parallel holding of his hand-controllable work tool proposed. To support the precise working of the hydraulic cylinders and ensure that parallel guidance is also really synchronous and proportional takes place, sensors are provided here. A sensor for the position of the work tool and a sensor for an arm sensor work together that the most plane possible processing of a certain level by multi-way valves and connections of the hydraulic cylinders.

The exchange of hydraulic fluids with these three concepts from the State of the art is carried out by cylinders of equal volume and stroke a certain geometry. The hydraulic function between the lifting cylinders and device cylinder is usually ensured by two load holding valves that set the working pressure. The area ratio of these two load holding valves for the opening pressure, however, is a problem with such known devices.

This results in a loss of lifting power, which is carried out in parallel with all hydraulic ones Working tools occurs. If there is too much loss of lifting power, the uneconomical. A relevant part of the energy used goes lost useless. The work tool remains among its possible uses. In addition, the accuracy of parallel guidance is no longer guaranteed.

The area ratio for the load holding valves is in common hydraulic Parallel loaders between 4: 1 and 8: 1. This then results in practice a loss of lifting power in such devices between 12% and 20%, which for the Users of such devices are very substantial and uneconomical.

The object of the invention is, in contrast, a vehicle with an improved Propose parallel guidance in generic control devices.

This object is achieved in that a second drive for rotating the Working tool is provided at the free end of the fastening device, and that the second drive is independent of that provided by the linear drive Lifting capacity is.

So it becomes a completely independent hydraulic control for the relative position of the working tools, for example the pallet forks, which are not in hydraulic or mechanical connection with the lifting of the Work tool is on the vehicle. There is therefore a decoupling of the two movements, although these two movements are uniform should. Nevertheless, a safe parallel guidance is achieved.

It is particularly preferred if a sensor is provided that the Sensor is a sensor that detects the relative orientation, and that the Output value of the sensor as an input value for the control device for the Position of the working tool is used.

According to the invention, a sensor is used in one possible embodiment, which is arranged on the vehicle and feels the current position, in particular thus the relative position to the horizontal. This sensor then gives corresponding information about a transmission path. This transmission route can be an electrical wire, but it can also be a wire wireless transmission via radio, in special cases also via optical signals, or other information carriers.

This information is recorded on the work tool by a recipient. This receiver then controls the device cylinder, for example a tilt cylinder.

A variant of this possibility is the angle of rotation of the base part to tap and over an information transmission link the implement and to supply a corresponding element available there.

Instead of tapping the real position on the vehicle, it is special in one preferred embodiment also possible in the implement itself Determine relative position to the horizontal or to a previous state. There are also several options for realizing such a sensor. One is a gyroscope in or adjacent to the implement provided.

Another possibility in this embodiment is gravity-related Control, so like a pendulum.

Another option is to track it here using separate servomotors to reach.

An additional unexpected advantage can also be achieved with the invention, which is not the case with conventional parallel guides, namely neither those who work with mechanical means still those who have one Exchange of hydraulic fluids that cause parallel guidance.

On closer inspection, the term "parallel guidance" can be found in split two terms that are slightly different in meaning. The The first of these two terms is the so-called "vehicle parallelism". This corresponds a parallel guidance, as in all the devices described above is sought from the prior art. The work tool should be as possible behave in parallel and in sync with the vehicle. Even with vehicle movements or lifting by means of a lifting cylinder, the working tool stands always parallel, for example to the vehicle floor or another orientation surface or line on the vehicle.

However, a second term would be parallel to the ground, or more precisely one Parallelism to the horizontal. As a rule, vehicle parallelism or Parallelism to the horizontal is identical, namely when the vehicle with its Working tool moves on a flat surface or at a standstill on any Place works.

In the event of deviations from the level, for example when driving on a however, there is an inclined plane or over uneven ground Differences, since the vehicle floor is then of course no longer identical to that Is horizontal.

According to the invention, a targeted, appropriately dosed deviation can now be made controlled by an exact parallel. So it can happen that a vehicle with a pallet fork or a scoop or similar Tools over uneven terrain. This causes the fastener with its end connected to the vehicle the bumps of the site and with a hydraulic or mechanical transmission exactly the bumps on the other end with the working tool be transmitted. This has to be done conventionally by being careful Driving or other efforts will be offset. According to the invention can now be disregarded the exact angle of rotation of the fastening device to tap for their end connected to the vehicle, Instead, for example, the sensor can directly determine the relative position Recognize the horizontal and pass this setting on to the working tool. This means that uneven floors are completely absorbed.

Of course, combinations are also possible, depending on the purpose of the control device Various functions can be provided become.

Inclination sensors, for example, are suitable as sensors. These are relative inexpensive, but still quite accurate. They work completely without wear and tear have an analog or a digital signal output. This is one Further processing of the measurement signals in a computer is possible without any problems.

Yaw rate sensors can also be used as sensors, which belong to the Gyro systems belong. Solid gyros, for example, are suitable here, who work according to the vibration structure method using the Coriolis force, So use the relative inertia as a basis.

Vehicles and work tools with the invention can be used without any problems Control device are equipped, other conventional functions continue to run. So these are not affected. This applies approximately for functions such as "parallel off", ie if a parallel guidance or modification of which may not be desired in a particular current operation should, and also for the "rapid traverse" function, which in connection with the Emptying the work tool is used.

Other additional functions can also be used when using the invention Win conception.

So additional sensors or additional properties of the same can Sensor are provided, which carry out a weighing of the blade contents. This weighing device can, for example, be a digital, self-summing Have a net weighing device. These values can be used in the control are also taken into account because the load on the work tool in predictable way of achieving and maintaining a position required forces influenced.

These sensor measured values can of course also be used for other purposes become.

The second independent drive for the rotation of the working tool has further advantages. This enables targeted vibration and vibration forces for the work tool, which are applied in a series of Use cases are desired. These forces are much better Decouple from the linear actuator and the vehicle.

A function can also be provided, which is the work tool any position immediately when it is emptied into a horizontal position. That too was hardly or only very difficult with conventional controls additional measures possible.

The operation for the second drive can be designed very comfortably, and with integrated for the linear actuator. Here is the use of control units to think like a joystick. If necessary, you can other functions are also added, such as those for tillage for tractor work tools.

Figur 1

eine schematische Seitenansicht eines Schaufelladers, der mit einer Steuereinrichtung nach der Erfindung ausgerüstet ist;

Figur 2

ein Schaltbild für eine Steuereinrichtung einer ersten Ausführungsform der Erfindung,

Figur 3

eine schematische Darstellung einer Parallelführung; und

Figur 4

eine weitere schematische Darstellung einer Parallelführung.

An exemplary embodiment of the invention is explained in more detail below with reference to the drawings. Show it:

Figure 1

is a schematic side view of a shovel loader, which is equipped with a control device according to the invention;

Figure 2

1 shows a circuit diagram for a control device of a first embodiment of the invention,

Figure 3

a schematic representation of a parallel guide; and

Figure 4

another schematic representation of a parallel guide.

1 schematically shows a vehicle 10, here a shovel loader. The vehicle 10 has four wheels 11, two of which are visible in FIG. 1. The body 12 with the area contained therein for the driver can also be seen.

On its front part is a pivotable up and down about a pivot point 15 Fastening device 20, for example a lifting rocker is arranged. At the front end 21 of the lifting arm or other fastening device 20, a bearing 22 is provided. Around this bearing 22 is a work tool 30 rotatably mounted, in the present case this work tool 30 designed as a shovel and shown in three different positions. Instead of a lifting fork, you can also use working platforms, a skip or another tiltable work tool may be provided.

The lifting arm or fastening device 20 is by means of a lifting drive 25 movable, which has a lifting cylinder on the one hand on the vehicle 10 and on the other hand is attached to the lifting arm 20.

The working tool 30 according to the invention has a second drive 35 which is independent of the lifting force of the lifting drive 25. The drive tool 30 is via a toggle lever 33 with the piston 36 of a hydraulic tilt cylinder connected. The tilt cylinder also has a cylinder housing that is pivotally mounted on the lifting arm or fastening device 20. The work tool 30 can be moved by moving the tilting cylinder piston 36 via the toggle lever 33 from a horizontal or parallel position denoted by B. in a tilting position A inclined towards the horizontal, bring a tilted tilt position C and any intermediate positions.

Position B is also the basic position or position 0.

As Figure 1 also shows plastically, in addition to this possibility of turning or tilting the work tool 30 around the bearing 22 also possibilities are provided, the work tool 30 parallel to the vehicle 10 and / or horizontally and therefore parallel to the ground when the vehicle 10 via the linear actuator 25, the elements attached to it (lifting arm or fastening device 20, working tool 30) up or down moves. The horizontal or parallel position should also be maintained if the lifting cylinder of the lifting drive 25 the lifting arm or fastening device 20 just lifts, for example because of the work tool 30 load resting on the floor is to be lifted upwards.

This is now possible with the control device according to the invention shown in FIG .

This control device can either with essential components Vehicle 10 or also arranged adjacent to work tool 30 his. Both variants have their advantages, since either work tool equipped with a control device specially designed for this tool can be or also cost-saving for different work tools only one control device, then be provided on the vehicle got to.

The control device first includes a sensor 40, for example a displacement sensor or tilt angle sensor. Only the rotation has to be regulated about a single axis, since the axis of rotation of the work tool 30 is fixed is. The vertical direction is determined by the direction of gravitational acceleration given and therefore only one angular position relative to the vertical can be set.

The sensor 40 outputs its measured values to a computer 41, these being passed on can certainly take place over a certain distance, if such as the sensor 40 on the tool 30 and the computer 41 on the vehicle 10 is.

The control device thus acts as a position controller. Here is a in Figure 2 Two-point controller is provided, which has an integrated inclination angle sensor features. The output signal of the inclination angle sensor corresponds to the actual value the angular position. As long as this actual value is in the range from -1 ° to + 1 ° (in relation to the angle), the controller does not intervene, as this is only for continuous operation leads. However, if the actual value exceeds the range from -1 ° to + 1 °, then controls the control device with the help of two complementary switches Corresponding proportional solenoid valves. The proportional control unit is provided overall with the reference number 42.

In this way, the actual angle of inclination in is set by means of an adjusting device brought the desired angular interval.

The control device can also have an activation input as well have the option of connecting a remote operating display.

In Figure 3 , the operation of the parallel guide is shown schematically. The illustration is limited to the fact that the vehicle 10 with the pivot point 15 is standing on the floor 17. The fastening device 20 extends from the pivot point 15 away from the vehicle 10. FIG. 3 shows four different directions in which this fastening direction 20 could be directed by way of example.

At the other end of the fastening device 20, the bearing 22 is again closed recognize, on which in turn the working tool 30 is arranged.

In this example, the sensor 40 (not shown) is located at the pivot point 15 fixed by what angle the fastening device 20 relative to Vehicle 10 is inclined. As an example here are the angles a °, b °, c ° and d ° for the four mentioned positions. Overall, the function runs smoothly.

The information about this angle is now transmitted via the computer 41 and ensures that this angle uses a °, b °, c ° or d ° on the bearing 22 in order to position the work tool 30 via the second drive 35 adjust. In the example shown, this stands in all four cases horizontal or parallel to the floor 17.

FIG. 4 shows how the parallel guidance according to the invention can also work.

Here a floor 17 is shown which clearly contains an inclined plane, that is to say differently than in Figure 3, which otherwise corresponds to the representation. Here it is assumed the sensor 40 is an inclination sensor arranged on the working tool 30. In FIG. 4, for example, this represents the deviation or the angle a °, b °, c °, or d ° of the fastening view 20 with respect to a vertical fixed, that is, regardless of the orientation of the vehicle 10 and the slope of the floor 17. The four angles on the right side of the (symbolic) vehicle 10 are additional to illustrate the inclined plane of the bottom 17 applied. Within or directly on the working tool 30, the Sensor 40 or its output value only the control device for the position of the Work tool 30 cause the latter exactly horizontal or parallel to Level. Of course, this is not parallel to the ("crooked") floor 17 or to the vehicle 10.

In the right half of FIG. 4 there is yet another variant of a control with sensor 40, computer 41, proportional control 42 and second drive 35 shown.

LIST OF REFERENCE NUMBERS

10

vehicle

11

bikes

12

body

15

pivot point

17

ground

20

Fastening device, for example lifting arm

21

front end of the lifting arm

22

camp

25

Lift drive, with a lifting cylinder

30

work tool

33

toggle

35

second drive, with a tilt cylinder

36

piston

40

sensor

41

computer

42

Proportional controller

A

tilted upward position

B

parallel position

C

tilted tilt position

Claims (6)

Vehicle (10) with a work tool (30), in which the working tool (30) is connected to the vehicle (10) via a fastening device (20), in which the fastening device (20) is rotatably connected to the vehicle (10) at one end (15), in which the fastening device (20) is rotatably connected to the working tool (30) at its other free end (21), in which a lifting drive (25) is provided which pivots the fastening device (20) upwards or downwards about its end (15) which is rotatably connected to the vehicle (10) and thus raises or lowers the working tool (30), in which a control device for the position of the working tool (30) is provided, which control device has a parallel guide device for the working tool (30), characterized in that a second drive (35) for rotating the work tool (30) is provided at the free end (21) of the fastening device (20), and
that the second drive (35) is independent of the lifting force applied by the lifting drive (25). Vehicle (10) according to claim 1,
characterized in that a sensor (40) is provided,
that the sensor (40) is a sensor that detects the relative orientation, and
that the output value of the sensor (40) is used as an input value for the control device for the position of the work tool (30). Vehicle (10) according to claim 2,
characterized in that the sensor (40) is arranged on the vehicle (10),
that a transmission link with a transmitter on the vehicle (10) and a receiver on the work tool (30) is provided,
so that information is sent from the transmitter via the transmission link to the second drive (35) on the work tool (30) for parallel guidance. Vehicle (10) according to claim 3,
characterized in that the sensor (40) taps the angle of rotation of the fastening device (20) relative to the vehicle (10) and emits a corresponding signal via the transmission link to the second drive (35) on the working tool (30). Vehicle (10) according to claim 2,
characterized in that the sensor (40) is provided on the working tool (30) and measures a relative position to the horizontal or another predetermined direction and controls the position of the working tool (30) via the second drive (35). Control device for a work tool (30) on a vehicle (10) according to one of the preceding claims,
characterized in that the control device has a second drive (35) for rotating the work tool (30) at the free end (21) of the fastening device (20), which second drive (35) is independent of the lifting force applied by the lifting drive (25) ,

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