HYDRAULIC SOLUTIONS ON A WORK MACHINE

Abstract

Hydraulic solutions on a to a tractor or equivalent connected work machine, where the work machine shows several hydraulic driven work units and hydraulic motors, and where the hydraulic motors are so mounted and connected that the pressure drop over the hydraulic motor of the most congested work unit also in static conditions can increase markedly over the system pressure of the hydraulic power source that drives the work machine and where the rotors of the hydraulic driven working units can be reversed to free a possible blockage.

Claims

1-9. (canceled)

10. Hydraulic solutions in to an agricultural tractor or equivalent connected stone picker where the stone picker shows at least one not rotating central work unit and at least one with this cooperative rotating work unit at least one hydraulic motor and at least one hydraulic actuator, wherein the hydraulic actuator or actuators and the hydraulic motor or motors of the rotating work units are hydraulically separated from each other and where the length of the actuator or actuators for the height adjustment, without supply of extern pressure fluid to the automatic height adjustment circuit, during work automatically is adapted as well to the pulling resistance of the stone picker as to the rotation resistance of its rotating work elements within the scope of a limited work range of the automatic depth control.

11. Hydraulic solutions in to an agricultural tractor or equivalent connected stone picker where the stone picker shows at least one not rotating central work unit and at least one with this cooperative rotating work unit at least one hydraulic motor and at least one hydraulic actuator, wherein the hydraulic actuator or actuators and the hydraulic motor or motors of the rotating work units are hydraulically separated from each other and where the length of the actuator or actuators for the height adjustment, without use of electrically, hydraulically or mechanically controlled metering units, during work automatically is adapted as well to the pulling resistance of the stone picker as to the rotation resistance of its rotating work elements within the scope of a limited work range of the automatic depth control.

12. Hydraulic solutions according to claim 10, wherein the actuator or actuators and the hydraulic motor or motors of the rotating work units are hydraulically separated from each other by one or more double acting cylinders separating the two hydraulic circuits from each other.

13. Hydraulic solutions according to claim 10, wherein the actuator or actuators and the hydraulic motor or motors of the rotating work units are hydraulically separated from each other by two or more single acting, in pairs with each other mechanically connected, hydraulic cylinders separating the two hydraulic circuits from each other.

14. Hydraulic solutions according to claim 10, wherein the area ratio, of the double acting cylinder or cylinders or of the in pairs with each other mechanically connected single acted cylinders, decide how the ratio between the registered rotation resistance and the registered pulling resistance of the work element or work elements do effect the length of the height 10 adjustment actuator, or height adjustment actuators.

15. Hydraulic solutions according to claim 10, wherein the hydraulic volume of the cylinder or cylinders to separate the height adjusting actuator or height adjusting actuators and the hydraulic motors from each other limits the motion range of the load depending depth control.

16. Hydraulic solutions according to claim 10, wherein the by driver regulated oil supply to the actuators always can displace the automatic depth control.

17. Hydraulic solutions according to claim 10, wherein at least one lift cylinder of the hydraulic driven rake units is connected to the return line of the hydraulic motor of the rake unit and that between the lift cylinder and the hydraulic motor is an one way restrictor valve to increase the pressure in the return line when the motor is reversed so that the rake unit automatically is offloaded from the ground when its motor is reversed to free the rotor from a blockage and to simultaneous reduce the reverse speed of the rotor.

18. Hydraulic solutions according to claim 10, wherein the pulling resistance of the not rotating central work unit is registered by one or more hydraulic cylinders co-operating with the connection between the work machine and the tractor.

19. Hydraulic solutions according to claim 11, wherein the actuator or actuators and the hydraulic motor or motors of the rotating work units are hydraulically separated from each other by one or more double acting cylinders separating the two hydraulic circuits from each other.

20. Hydraulic solutions according to claim 11, wherein the actuator or actuators and the hydraulic motor or motors of the rotating work units are hydraulically separated from each other by two or more single acting, in pairs with each other mechanically connected, hydraulic cylinders separating the two hydraulic circuits from each other.

21. Hydraulic solutions according to claim 11, wherein the area ratio, of the double acting cylinder or cylinders or of the in pairs with each other mechanically connected single acted cylinders, decide how the ratio between the registered rotation resistance and the registered pulling resistance of the work element or work elements do effect the length of the height 10 adjustment actuator, or height adjustment actuators.

22. Hydraulic solutions according to claim 11, wherein the hydraulic volume of the cylinder or cylinders to separate the height adjusting actuator or height adjusting actuators and the hydraulic motors from each other limits the motion range of the load depending depth control.

23. Hydraulic solutions according to claim 11, wherein the by driver regulated oil supply to the actuators always can displace the automatic depth control.

24. Hydraulic solutions according to claim 11, wherein at least one lift cylinder of the hydraulic driven rake units is connected to the return line of the hydraulic motor of the rake unit and that between the lift cylinder and the hydraulic motor is an one way restrictor valve to increase the pressure in the return line when the motor is reversed so that the rake unit automatically is offloaded from the ground when its motor is reversed to free the rotor from a blockage and to simultaneous reduce the reverse speed of the rotor.

25. Hydraulic solutions according to claim 11, wherein the pulling resistance of the not rotating central work unit is registered by one or more hydraulic cylinders co-operating with the connection between the work machine and the tractor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Below an advantageous embodiment of the invention is described with use of the following drawings.

[0031] FIG. 1. Shows a top view of a stone picker, using the hydraulic solutions of the invention.

[0032] FIG. 2. Shows the same machine in a side view.

[0033] FIG. 3. Shows the same machine in a rear view.

[0034] FIG. 4. Shows a typical hydraulic scheme for the hydraulic solutions according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0035] FIG. 1. Shows a top view of the stone picker, where for the understanding of the invention the most essential components are numbered. Left and right rake units 2 and 2, hydraulic motor for left and right rake 3 and 3, lift cylinders for left and right rake units 4 and 4, lift rotor 5, left and right hydraulic motor for the lift rotor 6 and 6.

[0036] FIG. 2. Shows a side view of the stone picker, where for the understanding of the invention the most essential components are numbered. Carrier frame 7, with tandem unit 8, support wheels for the stone rakes 9, drawbar 10, drawbar pull cylinder 11, drawbar height adjustment cylinder 12 and the siew heads 13.

[0037] FIG. 3. Shows a rear view of the stone picker, where for the understanding of the invention the most essential components are numbered. Siew under the lift rotor 13.

[0038] FIG. 4 shows the hydraulic scheme of the stone picker where for the understanding of the invention the most essential components are numbered.

[0039] The rotors drive circuit: The tractor external hydraulic connection pressure 14, cylinder 20, left and right hydraulic motor 6 and 6 for the lifting rotor, control valves 15 and 15 for left and right rake units, pivot operated check valves 16 and 16 for the left and right lift cylinders, lift cylinders for left and right rake units 4 and 4, non-return valves with restricted bypass left and right 17 and 17, hydraulic motors for left and right rake units 3 and 3.

[0040] Height adjustment circuit: The tractor external double acting connection 18, pivot operated check valve 19, height adjustment cylinders left and right 12 and 12, cylinder 20 and the pull cylinder 11 of the drawbar.

[0041] Note, for the hydraulic connection to the tractor is only one double acting and one single acting connection+free return used. No from tractor electrically or cable operated hydraulic valves are needed.

[0042] The function of the hydraulic solutions according the invention is as follow:

[0043] The not shown mechanical transport security lock for the rakes are opened. The tractor external hydraulic 14 is activated and the lift rotor 5 starts. As the operating valves 15 and 15 for the rake units are activated in +position the rake units are lowered since the return pressure from the hydraulic motors 3 and 3 of the rake units are big enough to open the check valves 16 and 16.

[0044] Bout of the rake units keeps now the same speed as they ar driven by the return oil from the equal sized hydraulic motors 6 and 6 which are synchronized with each other through the lift rotor shaft 5 and therefore distribute the oil from the reactor evenly to bout of the rake units independent of their load.

[0045] The required working depth is set by the tractor external hydraulic connection 18. The pivot operated check valve 19 prohibit during work the oil from leaking out of the height adjusting cylinders 12 and 12 back to the tractor.

[0046] When the machine is operating normally, the pressure in the height adjustment cylinders 12 is equal high as the pressure on the piston rod side in the pull cylinder 11 of the drawbar.

[0047] If the machine tends to sink to deep, the pulling resistance will increase and the pressure in the pull cylinder 11 of the drawbar will increase. Then oil is led from this cylinder 11 to the high adjustment cylinders 12 and the working depth will decrease.

[0048] Here we have a kind of an automatic depth control based on the pulling force, it means depending on how deep the siew edges 13 penetrate in the soil and how hard the soil is.

[0049] How deep the siew edges work desire also how deep the lifting rotor 5 and also how deep towards the raking rotors directed parts of the rakes do work. At increased working deep and or at heavier soil or by increased stone presence or by increased speed, the rotation resistance for all three rotors does increase, most of course for the lifting rotor 5 but also for the rake unit rotors 2.

[0050] From the hydraulic scheme we can see that the pistonrod side of the cylinder 20 is in connection with the height adjustment cylinders 12. The cylinder 20 thus separate the oil in the rotation drive and in the height adjustment circuits from each other, but keeps the pressure relation between the pressure in these circuits on the level given by the area relation between the bout chambers of the cylinder 20 gives.

[0051] This mean that the higher rotation resistance the rotors get, the more oil will be pressed out of the cylinder 20 to the height adjustment cylinders 12 and opposite, the lower the rotation resistance for the rotors is, the more oil is let out from the height adjustment cylinders 12 to the cylinder 20 and the working depth of the machine will increase.

[0052] Therefore we get a load adapting depth regulation that not only take in account the pulling force, but the depth regulation is a function of all the parameters: working depth, soil stiffness, stone presence, working speed and the rotation speed of the rotors. If the depth control is marked by Z, this regulation can be written as a function:

Z=(working depth,soil stiffness,stone presence,working speed,rotation speed).

[0053] The area ratio between the piston- and piston rod sides of the cylinder 20 determinate, to what amount the of the rotation resistance depended parameters influence on the depth control, in relation to how those parameter, who only are related to the pulling force in the drawbar.

[0054] Thus it can oft be a benefit to connect a second cylinder with another area ratio in parallel to the cylinder 20 to get the possibility to during work adjust what influence (how heavily) the different parameters will have on the load depending depth control Z.

[0055] When we look at the rotor drive we did already notice that bout of the hydraulic motors of the lifting rotor do work also as flow dividers and do synchronize the speed between the rotors.

[0056] When we look at the dynamic pressure drop over the hydraulic motors we can for example look at a situation where the load on the left rake unit 2 increase while the load on the right hand rake unit 2 remain constant. The pressure drop over the hydraulic motor 3 of the left hand rake unit increase. This results in a decreasing of the pressure drop over the hydraulic motor 6 of the lifting rotor. The two hydraulic motors 6 and 6 do therefore give different torque on the shaft of the lifting rotor 5, in extreme case so that the left hydraulic motor instead of giving part of its effect to the lifting rotor instead is driven by this and then will act as a pump and can increase the working pressure of the hydraulic motor 3 of the left rake unit to the maximum pressure limit of the control valve 15, thus much higher than the system pressure of the tractor external hydraulic.

[0057] The connection of the hydraulic motors according to the present innovation, results in a power distribution between the hydraulic motors of the three rotors and supply the maximum power to that hydraulic motor that instantaneous has the highest external load. Here is not only the hydraulically supplied power used, but also the kinetic energy stored especially in the heavy lifting rotor 4 with large diameter, but also the kinetic energy of the right had rake rotor is used to help the hydraulic motor of the left hand rake rotor over the load peak and vice versa.

[0058] Is the load of the hydraulic motor of the left hand rake rotor all too big, the pressure relief valve of the control valve 15 at 250 bar and oil can the free bypass the motor 3 to tank. Thus at this overload also heavy heating will occur, an effective cooling of the overload protection is present by the continuous oil flow through the valve and the relief pressure of the valve is kept on an even level without need of readjustment, cleaning operations or changing of parts as usually is the case by the traditional over load protections that up to now have been dominating on the stone pickers on the market.

[0059] If the rake rotor tends to stop because of tree roots or branches winding around it, or because of a suitably shaped stone that itch in between its throw fingers and the frame, with a hydraulic solution according the present innovation it is only needed to reverse its control valve 15. The oil will then be directed to the lift cylinder 4 of the rake unit and release the unit from the ground. Simultaneous part of the oil will flow through the restricted bypass 17 of the relief valve to slowly reverse the rake rotor to release the blockage and the work can continue with a minimum of standstill and with maximum of safety for the driver.

[0060] The fact that the load on the rotor first is automatically reduced by the oil supplied to the lit cylinder will of course help to reverse the rotor and release the blockage.

[0061] As the above-described examples shows, the hydraulic solution of the present innovation has many advantages compared to the state of the art hydraulic solutions in stone pickers. The work machine does of course not be a stone picker, but can be any work machine getting its hydraulic power supply from a base machine and who's own weight at least partly is unloaded by this. The number of driven rotors is neither limited to two, but can be any number.

[0062] The area of use is neither limited to a within the agriculture used working machine, but can be for example a machine used within road or landscape construction and many variations thereof are possible within the scope of the patent claims below.

REFERENCE NUMBER LIST

[0063] Ref Name/description [0064] 1 Stone picker [0065] 2 Left rake unit [0066] 2 Right rake unit [0067] 3 Hydraulic motor of left rake unit [0068] 3 Hydraulic meter of right rake unit [0069] 4 Lift cylinder of left rake unit [0070] 4 Lift cylinder of right rake unit [0071] 5 Lifting rotor [0072] 6 Left hydraulic motor of lifting rotor [0073] 6 Right hydraulic meter of lifting rotor [0074] 7 Main frame [0075] 8 Tandem unit [0076] 9 Support wheels for the rake units [0077] 10 Drawbar [0078] 11 Pull cylinder of the drawbar [0079] 12 Height adjusting cylinder left [0080] 12 Height adjusting cylinder right [0081] 13 Slew beneath the lifting rotor [0082] 13 Sieve edges [0083] 14 Tractor external hydraulic connection pressure [0084] 15 Control valve of left rake unit [0085] 15 Control valve of right rake unit [0086] 16 Pivot operated check valve of left lift cylinder [0087] 16 Pivot operated check valve of right lift cylinder [0088] 17 Non return valve with restricted bypass left [0089] 17 Non return valve with restricted bypass right [0090] 18 Tractor external double acting hydraulic connection [0091] 19 Pivot operated check valve [0092] 20 Cylinder