Abstract
The invention relates to a hydraulic positioning device for an agricultural implement, wherein preferably a uniform movement of several hydraulic cylinders is achieved by using a progressive distributor.
Claims
1. Hydraulic positioning device (1), in particular for use as a positioning system of an agricultural machine, comprising at least one controllable or regulatable pressure supply (12) and at least one distribution device (2) connected thereto, wherein at least a first and a second hydraulic cylinder (3, 4) are in hydraulic connection with the distribution device, characterized in that the distribution device (2) is designed as a hydraulic progressive distributor (7, 8) which, by means of at least two distribution pistons (K1, K2), arranged in a downstream circuit, feed the fluid flow of the pressure supply (12) to the hydraulic cylinders in defined amounts (3, 4).
2. Positioning device according to claim 1, characterized in that at least two connections (w, x) of the distribution device (2) are connected to one another and to a hydraulic cylinder (3, 4) in a parallel circuit.
3. Positioning device according to claim 1, characterized in that the hydraulic cylinders (3, 4) are connected to the pressure medium supply (12) via check valves (13, 14) or shut-off valves in the bypass to the distribution device (2).
4. Positioning device according to claim 1, characterized in that the distribution device (2) is designed as a hydraulic progressive distributor (7, 8) with at least two distribution pistons (K1, K2) in a sequence control circuit, wherein the distribution pistons (K1, K2) are secured by a mechanical forcing control against a simultaneous distribution movement.
5. Positioning device according to claim 1, characterized in that the distribution pistons (K1, K2) of the hydraulic progressive distributor (7, 8) with variable or adjustable end stops are limited in their stroke movement.
6. Positioning device according to claim 1, characterized in that the distribution device (2) is at least partially formed as a cascade of several progressive distributors (7, 8) between the pressure supply (12) and the hydraulic cylinders (3, 4).
7. Positioning device according to claim 1, characterized in that at least two of the hydraulic cylinders (3, 4) are designed as double-acting hydraulic cylinders and are connected to a pressurized medium supply (12), wherein at least the piston crown sides (9) or the piston ring sides (10) of the hydraulic cylinders (3, 4) are connected to a distribution device (2).
8. Positioning device according claim 7, characterized in that the hydraulic cylinders (3, 4) are provided as double-acting hydraulic cylinders on the piston crown side (9) and/or the piston ring side (10) with an end position valve which hydraulically connects the piston crown side (9) and the piston ring side (10) together.
9. Positioning device according to claim 8, characterized in that the piston crown sides (9) and/or the piston ring sides (10) of the double-acting hydraulic cylinders (3, 4) are connected via a distribution device (2) or directly to a pressure supply (12), wherein at least one check valve (11) is arranged between at least one cylinder (3, 4, 5, 6) and the distribution device (2) and/or the pressure supply (12).
10. Positioning device according to claim 9, characterized in that at least one hydraulic cylinder (3, 4, 5, 6) is provided as a memory cylinder or as a double cylinder with a common piston rod.
11. Positioning device according to claim 9, characterized in that at least one hydraulic cylinder (3, 4, 5, 6) is equipped with a displacement measuring system which is connected to a display, control or regulating device.
12. Positioning device according to claim 1, characterized in that at least one distributor piston (K1, K2) of a progressive distributor (7, 8) is provided with a movement measuring system which is connected to a counter, a display, control or regulating device.
13. Agricultural implement with a positioning device according to claim 1, characterized in that the positioning device (1) of a segment-wise pressure or depth adjustment of the working, dispensing or depth-guiding devices or of the folding device is assigned to such a device.
14. Plow with a positioning device claim 1, characterized in that the positioning device (1) is used for the parallel cutting width adjustment of a plurality of plow bodies, which are arranged to be pivotable relative to the plow frame, wherein the plow bodies are supported on the frame by means of the hydraulic cylinders.
Description
[0022] Further details and advantages of the subject matter of the invention may be gathered from the following description and the associated drawings, in which an exemplary embodiment with the necessary details and individual parts is shown:
[0023] FIG. 1 shows a synchronization circuit of two hydraulic cylinders according to the invention,
[0024] FIG. 2 shows a synchronization circuit of several double-acting hydraulic cylinders according to the invention, and
[0025] FIG. 3 shows a simplified schematic of a progressive distributor in 4 views.
[0026] FIG. 1 describes the basic design of a circuit according to the invention of the positioning device 1. The supply and return of a pressurized fluid, preferably hydraulic oil, takes place via the pressurized supply 12. The pressure supply is thus part of a tractor, while the remaining circuit components are part of an agricultural device. The pressure supply 12 consists of a pump 15, a tank 16 or a suitable reservoir, as well as a multi-path valve 17 for controlling the pressurized fluid flow. The pressure supply 12 or its components may be assigned to a tractor, but also to the device and even have its own independent power supply. If the valve slide of the multi-path valve 17 in FIG. 1 is moved to the right from the depicted neutral middle position, there is a fluid flow into the inlet of a distribution device 2, which is shown here as a single progressive distributor 7. If, for example, the progressive distributor 7 has four outputs, two outputs are respectively connected to a single-acting hydraulic cylinder 3, 4. Likewise, the displacement chambers of the distribution pistons of the progressive distributor 7 may be interconnected internally, so that, for example, there are only two outputs from the progressive distributor 7. Optionally, the outputs of the progressive distributor 7 are provided with check valves 20, 21 for their relief. The distribution pistons of the progressive distributor 7 move forcibly one after the other under the pressure of the fluid flow and displace a small defined quantity of fluid alternately and successively into the outputs and the connected left hydraulic cylinder 3 or right hydraulic cylinder 4. According to the allocated fluid volume, the two hydraulic cylinders 3, 4 alternately travel in small steps. This results in a load-independent synchronized connection of the two hydraulic cylinders 3, 4 whose stepwise movement causes only negligibly small inaccuracies in the synchronization. If the valve slide of the multi-path valve 17 is moved into the opposite left position, the hydraulic fluid may flow back into the oil tank 16 of the pressure supply 12 under the load of the hydraulic cylinders through the two check valves 13 or 14. If the progressive distributor is not self-blocking in the opposite flow direction, the hydraulic fluid may also flow through the progressive distributor in the reverse order of movement of the distribution pistons. The check valves 13 and 14 as well as 20 and 21 are then superfluous. In this case, the progressive distributor produces a double-acting or reversed synchronization of the hydraulic cylinders 3, 4 in both positioning directions.
[0027] FIG. 1 shows just one example of a circuit according to the invention. Depending on the number of outputs of the progressive distributor, more hydraulic cylinders than represented may be connected or combined. Likewise, several progressive distributors may be connected in parallel, or cascaded in series. As a result, the connection possibilities for a multiplicity of hydraulic cylinders are increased or multiplied. Also, some outputs of the progressive distributor may be connected unused to the tank 16 via a return line. The synchronization of the hydraulic cylinders, which are connected to the remaining outputs of the progressive distributor, is thus maintained. For the basic operation of a progressive distributor, in particular the movement of its distribution pistons and their sequence control circuit, reference should be made to the above-cited prior art as well as to the description of FIG. 3. With a flow limiter, which is connected between the pressure supply 12 and the distribution device 2, the actuating speed of the device may be regulated and the distribution device may be protected against overloading. A simple throttle valve is sufficient here, for example.
[0028] FIG. 2 shows the schematic construction of a positioning device 1 with four double-acting hydraulic cylinders 3, 4, 5, 6, which are each provided with stop valves or hydraulically unlockable check valves 11 for securing and preventing uncontrolled movements, for example in the case of pressure loss. The unlockable check valves 11 may be integrated in the hydraulic cylinders or arranged separately. The pressure supply 12 is designed as described above in FIG. 1, but is provided with a double-acting multi-path valve 17. If the valve slide of the multi-path valve 17 is shifted to the right in the illustrated circuit diagram, hydraulic fluid flows under pressure from the pump 15 to the first progressive distributor 7. The fluid flow is thereby limited by a throttle valve or another, preferably adjustable flow limiter 19. The progressive distributor 7 is provided with four outputs, wherein one output is respectively operatively connected to a piston crown side 9 of the respective cylinder 3, 4, 5, 6. As a result of the forced movement of the distributor pistons within the progressive distributor 7, the hydraulic cylinders 3, 4, 5, 6 travel successively in small path increments, starting from cylinder 3 to cylinder 6. Thereafter, cylinders 3 etc. are moved again until the extended end position of the hydraulic cylinders is reached. In this case, each stop valve 11, which is connected to the hydraulic cylinders 3 to 6, releases the piston ring side 10 of the respective cylinders 3, 4, 5, 6 as long as it is pressurized by an output of the progressive distributor. The hydraulic fluid displaced on the piston ring side flows back into the tank 16 of the pressure supply 12 via several lines, which are interlocked with one another by check valves 13, 14. For the sake of clarity, only two of the illustrated check valves 13, 14 are provided with reference symbols. If the multi-path valve 17 is moved back into the middle neutral position, all four cylinders remain in a secure, blocked state through the upstream stop valve 11. If the valve slide of the multi-path valve 17 is moved into the opposite left position, hydraulic fluid flows from the pump 15 into the right-hand progressive distributor 8. The progressive distributor 8 is connected to the respective piston ring sides 10 of the hydraulic cylinders 3, 4, 5, 6. In a precisely opposite manner, as described above, the hydraulic cylinders now move incrementally one after the other until they reach the retracted end position. When a gate valve 18 is actuated, which is closed in regular operation, the cylinders 3, 4, 5, 6 may be driven back into a defined initial position in the event of small leaks occurring.
[0029] FIG. 3 shows the fluid course through a progressive distributor in four views. Starting from the inlet P, the fluid is forcibly and successively distributed in equal amounts to the outlets w, x, y, z by means of the distribution pistons K1 and K2. It is assumed that the progressive distributor is already filled in all channels.
[0030] In the first view of FIG. 3, the fluid passes under pressure from inlet P to the right side behind the distribution piston K1 and pushes it to the left. The fluid displaced on the left side of the piston is discharged via outlet z. In the next step in the second view, the fluid flows under pressure from inlet P to the right side behind the distribution piston K2 and likewise pushes it to the left. The fluid displaced on the left side of the piston is discharged via outlet w.
[0031] In the third step in the third view, the fluid flows under pressure from inlet P to the left side behind the distribution piston K1 and pushes it to the right. The fluid displaced on the right side of the piston is discharged via outlet x. In the final step of the sequence control circuit in the fourth view, the fluid flows under pressure from inlet P to the left side behind the distribution piston K2 and likewise pushes it to the right. The fluid displaced on the right side of the piston is discharged via outlet y. Next, the process starts from the front, as previously described for the first view of FIG. 3 and the subsequent views 2 to 4. The outputs w and x as well as y and z are connected in parallel with each other via a closable bypass. In this way, two hydraulic cylinders may be actuated in synchronization. If the bypass is closed, four hydraulic cylinders may be actuated in synchronization. When the fluid flow of an outlet is returned into the tank, three cylinders may be actuated in synchronization. Further distribution piston segments may also be added. Accordingly, the number of possible outputs increases in pairs.
[0032] If the process is reversed by fluid pressure being applied to the outlet connections w, x, y, z, and the inlet P is reversed, fluid flows through the connection x behind the right side of the distribution piston K1 from the fourth view in FIG. 3. This moves to the left and displaces the fluid to the left of the piston into inlet P. Next, connection w is applied in the third view and pushes the lower distribution piston K2 to the right. The right-hand fluid volume of the distribution piston K2 is also displaced in the inlet P. In the second view, connection z and distribution piston K1 and, in the first view, connection y and distribution piston K2 are acted upon and displace the fluid analogously into the inlet P. The other pressurized outputs are interlocked by the respective piston position and fluid channels The resulting piston forces are canceled. As described at the outset, only the principle fluid flow is shown. If the two pistons are locked by means of hydraulic, mechanical or suitable devices, so that they do not move simultaneously, an operationally safe and optionally reversible force distribution system is obtained.
LIST OF REFERENCE NUMERALS/SYMBOLS
[0033]
TABLE-US-00001 1 Hydraulic positioning device 2 Distribution device 3 Hydraulic cylinder 4 Hydraulic cylinder 5 Hydraulic cylinder 6 Hydraulic cylinder 7 Progressive distributor 8 Progressive distributor 9 Piston crown side 10 Piston ring side 11 Unlockable check valve, stop valve 12 Pressure supply 13 Check valve 14 Check valve 15 Pump 16 Tank, reservoir 17 Multi-path valve 18 Gate valve 19 Flow limiter 20 Check valve 21 Check valve K1 Distribution piston K2 Distribution piston P Input connection progressive distributor w Output connection progressive distributor y Output connection progressive distributor x Output connection progressive distributor z Output connection progressive distributor
