EP1616103B1 - Control and adjustment system for a lifting and tilting mechanism of a machine tool in a mobile working machine - Google Patents

Description

The invention relates to a lifting or tipping mechanism of a mobile working machine according to the preamble of claim 1 or 4.

The working hydraulics in mobile machines with a shovel-shaped working tool - for example in wheel loaders, excavators and forklifts - consists of a hoist and a tipping unit. The hoist consists of a boom located between the vehicle body and work tool, which is hydraulically driven by two lifting cylinders and raises or lowers the working tool depending on the pivoting direction by a pivoting movement relative to the vehicle body. The tilting mechanism has one or two bucket cylinders, which are mounted between the vehicle body and the bucket-shaped working tool and drive the bucket tool depending on the tilting direction to an out or tipping tilting movement.

EP 0 564 939 B1 shows a hydraulic control device for such a working hydraulic system. The two lifting and bucket cylinders are each connected in parallel. The position and direction of movement of the actuating piston in the lifting cylinders determine the lifting height and the vertical direction of movement of the loading blade relative to the vehicle body. Similarly, the tilt angle and tilt direction of the bucket are determined by the position and direction of travel of the actuator piston in the bucket cylinders. Position and direction of movement of the actuating piston in the lifting or bucket cylinder are determined by the pressure difference between the piston-side and piston rod-side actuating pressure chamber. The supply of the piston-side and piston rod-side control pressure chambers in the individual Lifting and bucket cylinders with hydraulic fluid determined signal pressure is effected by a common pressure and flow controlled hydraulic pump.

Since this is a working in one-quadrant operation hydraulic pump, the switching of the control pressure differences between the piston side and piston rod side actuating pressure chamber of the lifting and bucket cylinder is realized via control valves in a control block in the hydraulic load circuit between the hydraulic pump and lifting and bucket cylinder. Each of these control valves - one control valve each for the hoist and tilting unit - is controlled via a pilot control unit to which a steering element, for example steering wheel or joystick, is connected, depending on the desired reference values - lifting height, tilt angle, vertical direction of movement and tilting direction.

A load-dependent dosage of the hydraulic fluid flow from the hydraulic pump to the individual lifting and bucket cylinders is realized via an intermediate circuit of a control valve (priority valve).

This hydraulic control of the lifting and bucket cylinder has a number of disadvantages:

The power level for the hydraulic hoist lies in a completely different order of magnitude than the power level for the hydraulic tipper (hoist: approx. 150 to 180 bar, tipping unit: approx. 20 to 50 bar). Since a single hydraulic pump is used for lifting and tilting, whose maximum delivery volume is designed for the hydraulic volume required by the hoist, resulting in the case of hydraulic actuation of the tipper a not insignificant hydraulic energy loss. This hydraulic energy loss generates additional dissipated heat, which unnecessarily degrades the hydraulic efficiency of the working hydraulics.

The interconnection of the hydraulic fluid flow from the hydraulic pump to the correct pressure chambers of the lifting and bucket cylinder according to the desired setpoints of the working hydraulics - lifting height, tilt angle, vertical Bewegungssichtung and tilt direction - can be realized only on complex control valves in control blocks due to the one-quadrant operation of the hydraulic pump become. The control engineering design of the control valves (for example, parameterization of the fine control grooves in the control valve) is very difficult. In addition, there is a significant piping and bolting costs for control blocks, which represents an additional risk for leakage oil points. The control blocks including the additional piping and screw connections require additional space. The effort for assembly, maintenance and service increases due to the greater system complexity. The control valves lead due to their adjustable flow cross-section to higher flow resistance in the hydraulic load circuit compared to a normal hydraulic load line between the hydraulic pump and hydraulic cylinder. Flow cross sections in the load circuit cause unnecessary hydraulic losses, which unnecessarily worsen the efficiency of such working hydraulics.

The invention is therefore based on the object, the hoist or tilting of a mobile machine according to the preamble of claim 1 or claim 4 such that the required for the desired setpoints of the working hydraulics - lifting height, tilt angle, vertical Bewegungssichtung and tilting direction - set pressures in the two actuating pressure chambers of the lifting and bucket cylinder from an adjustable hydraulic pump, directly without the interposition of additional control and adjusting devices, such as control valves in control blocks, are guided in the respective setting pressure chambers.

The object of the invention is achieved by a hoist or a tipping mechanism of a mobile machine with the features of claim 1 and of claim 4.

An essential feature of the lifting or tilting body according to claim 1 and claim 4 is in contrast to the device in EP 0 564 939 B1, in which an open hydraulic circulation is used, the use of a closed circuit between the hydraulic pump and the respective hydraulic consumer (lifting cylinder the hoist and bucket cylinder of the tipping unit). This presupposes that the delivery volume transported from the hydraulic pump to the hydraulic consumer corresponds to the delivery volume transported back from the hydraulic consumer to the hydraulic pump.

In a closed hydraulic circuit, in contrast to an open hydraulic circuit in the connected to the low-pressure side connection of the hydraulic pump control pressure chambers in the transition from expansion to compression no negative pressure arise. The cavitations occurring at negative pressure in the cylinders, which can lead to damage to the cylinders, do not occur in this case.

In a closed hydraulic circuit, it is possible to use a hydraulic pump operating in two-quadrant operation. This can be generated by adjusting the hydraulic pump with respect to the direction of current and the pending at its two terminals Stelldruckhöhen any control pressure difference for the two control pressure chambers of the lifting or bucket cylinder. A complex interposition of control blocks with control valves for the generation of any control pressure differences in the two control pressure chambers of the lifting or bucket cylinder from the unidirectional control pressure difference at the two Connections of the hydraulic pump is thus eliminated. The control pressure difference of the two ports of the hydraulic pump can be arbitrarily set with respect to their polarity and their height by an adjustment within the realizable adjustment range of the hydraulic pump. The adjustment of the necessary control pressure differences is thus shifted in this arrangement from the load circuit in the control circuit of the hydraulic pump.

The lifting or tilting device according to the invention of a mobile machine thus has the above-mentioned disadvantages - additional piping and Verschraubungsaufwand, increased space requirements, additional Leckölellen, increased installation, maintenance and service costs, lower flow resistance in the load circuit and especially higher system costs - no longer on ,

A parallel connection of the two lifting or bucket cylinders as in EP 0 564 939 B1 separates due to the different compression or expansion volumes in the piston-side and piston rod side actuating pressure chambers upon displacement of the actuating piston.

According to the invention, the two lifting or bucket cylinders are connected in opposite directions and the two lifting and bucket cylinders have the same expansion as compression volumes when the adjusting pistons are displaced. Same expansion as compression volumes in displacement of the actuating piston in the control pressure chambers of the lifting or bucket cylinder ensure equal delivery volumes in the outward and return lines for the realization of a closed hydraulic circuit.

Advantageous, in particular more detailed embodiments of the invention are specified in the dependent claims

A separate hydraulic pump is advantageous for the realization of a closed hydraulic circuit for the hoist and the tilting mechanism. Thus, the required for the control pressure chambers of the lifting or bucket cylinder control pressure differences can be set independently by the respective adjustment of the two hydraulic pumps. A mutual negative influence on the lifting and tilting function as in a realization by means of open hydraulic circuit is no longer available. Also, each hydraulic pump can be adapted in terms of their capacity to the power requirement of the lifting or tilting unit. In an open hydraulic circuit, the capacity of the hydraulic pump must be tailored to the needs of the most powerful consumer. The tipping unit is thus supplied with an open hydraulic circuit with too high a hydraulic power, which can unnecessarily worsen the efficiency of the tipping unit.

The control of the control valve for the adjustment of the two hydraulic pumps can be done electrically or hydraulically.

In the case of a hydraulic implementation, a pilot control device is used, which is controlled via a steering element, for example a joystick, in each case in a deflection dimension of the steering element for each hydraulic pump and thus for each hydraulic function - hoist, tilting mechanism. The pilot control device generates at its outputs according to the deflection of the steering member necessary for the deflection of the control valve piston control pressure pairs.

In the electrical control, the mechanical deflection of the steering member is transformed via a converter into an electrical signal which is supplied to the electric actuating magnet for the deflection of the control valve piston. Advantage of the electrical compared to the hydraulic control is the lower technical Effort - no piping, fittings and hydraulic valves - and the smaller footprint, especially in the cab of the driver. A simple system integration of the electrical control in existing control systems of the mobile work machine - for example, control for hydrostatic drive - is another advantage of the electrical control.

Connecting the piston-side and piston rod-side actuating pressure chambers of the bucket cylinder in the operating state of the "float position" of the mobile working machine, in which the bucket performs a leveling without adjustment pressure solely due to the dead weight of the bucket, is comparatively easy to implement a closed hydraulic circuit. While in an open hydraulic circuit for this operating condition, another control valve must be kept in a control block for it, in a hydraulic control and actuating system according to the invention, the two hydraulic load lines via a simply executed 2/2-way valve, which can be controlled electrically or hydraulically , short-circuited.

To avoid sinking or tilting back of the working tool in case of failure of one or both hydraulic pumps, electrically or hydraulically controllable (switchable) check valves - so-called "low-leak" valves - are used in one of the two hydraulic load lines to the lifting and bucket cylinders.

To avoid unwanted pitching movements of the working tool while the mobile working machine is being driven, a hydraulic control arrangement is used for damping the boom, as described, for example, in DE 41 29 509 C2. This hydraulic control arrangement loads the bucket cylinder targeted by adding hydraulic buffer to the expected load pressure and thus leads to a significant damping of pitching vibrations of the working tool.

In a parallel connection of the two lifting or bucket cylinder can be dispensed with in favor of a parallel interconnection, if in the cylinders instead of a one-sided piston rod an actuating piston is used with a two-sided piston rod. With a displacement of such a control piston in the cylinder, the expansion and compression volume in the two separated by the control piston control pressure chambers is the same size. Thus, the hydraulic fluid volume transported from the hydraulic pump to the hydraulic consumer - lifting or bucket cylinder - corresponds to the hydraulic fluid volume transported back from the hydraulic consumer to the hydraulic pump, which makes it possible to realize a closed hydraulic circuit.

Fig. 1A

Schaltbild eines ersten Ausführungsbeispiels eines erfindungsgemäßen Kippwerks;

Fig. 1B

Schaltbild eines ersten Ausführungsbeispiels eines erfindungsgemäßen Hubwerks;

Fig. 2A

Schaltbild eines zweiten Ausführungsbeispiels eines erfindungsgemäßen Kippwerks;

Fig. 2B

Schaltbild eines zweiten Ausführungsbeispiels eines erfindungsgemäßen Hubwerks;

Fig. 3A

Schaltbild einer Schaufelzylinderhydraulik eines dritten Ausführungsbeispiels des erfindungsgemäßen Kippwerks.

Fig. 3B

Schaltbild einer Hubzylinderhydraulik eines dritten Ausführungsbeispiels des erfindungsgemäßen Hubwerks.

Three embodiments of the invention are illustrated in the drawings and will be described in more detail below. Show it:

Fig. 1A

Circuit diagram of a first embodiment of a tilting mechanism according to the invention;

Fig. 1B

Circuit diagram of a first embodiment of a hoist according to the invention;

Fig. 2A

Circuit diagram of a second embodiment of an inventive Kippwerks;

Fig. 2B

Circuit diagram of a second embodiment of a hoist according to the invention;

Fig. 3A

Circuit diagram of a bucket cylinder hydraulics of a third embodiment of the tilting mechanism according to the invention.

Fig. 3B

Circuit diagram of a lifting cylinder hydraulics of a third embodiment of the hoist according to the invention.

The hydraulic control and positioning system for a work tool in a mobile work machine according to the invention will be described in two embodiments below with reference to FIGS. 1A to 3B.

FIG. 1A shows a circuit diagram of a hydraulic control and positioning system for a tilting mechanism 100 of a working tool in a mobile working machine, which comprises a first bucket cylinder 1 and a second bucket cylinder 2. In the first bucket cylinder 1, an actuating piston 3 is displaceably guided, which is mechanically coupled to the vehicle body 4. The first bucket cylinder 1 is mechanically connected to the loading bucket 6, which can be deflected relative to the vehicle body 4 in terms of tilt angle and tilting direction. In the second Bucket cylinder 2, the adjusting piston 5 is slidably guided, which is connected to the loading shovel 6. The second bucket cylinder 2 is mechanically connected to the vehicle body 4.

The first bucket cylinder 1 has a piston-side actuating pressure chamber 7 and a piston rod-side actuating pressure chamber 8. The second bucket cylinder 2 also has a piston-side actuating pressure chamber 9 and a piston rod-side actuating pressure chamber 10. The piston side actuating pressure chamber 7 of the first bucket cylinder 1 is connected to the piston rod side actuating pressure chamber 10 of the second bucket cylinder 2 via a hydraulic line 11. Similarly, the piston rod side actuating pressure chamber 8 of the first blade cylinder 1 via a hydraulic line 12 to the piston-side actuating pressure chamber 9 of the second blade cylinder 2 connected.

The piston rod-side actuating pressure chamber 10 of the second blade cylinder 2 or the piston-side actuating pressure chamber 7 of the first blade cylinder 1 is connected via a first hydraulic load line 13 to the first terminal 14 of an adjustable first hydraulic pump 15. The piston-side actuating pressure chamber 9 of the second bucket cylinder 2 or the piston rod-side actuating pressure chamber 8 of the first bucket cylinder 1 is connected via a second hydraulic load line 16 to the second port 17 of the adjustable first hydraulic pump 15. The adjustable first hydraulic pump 15 is driven via a drive shaft 18 by a prime mover (not shown in FIG. 1A), for example a diesel engine.

In each case a first actuating pressure chamber 68, 69 adjoins the associated cylinder piston 63, 65 with a pressure application area A1, which is smaller than the pressurization area A2, with which the other second control pressure chamber 67, 70 adjacent to the corresponding cylinder piston 63, 65. Each port 74, 77 the hydraulic pump 75 is connected to a first actuating pressure chamber 68, 69 having a smaller pressurizing area A1 and a second actuating pressure chamber 67, 70 having a larger pressurizing area A2.

A first feed pump 19 is also driven via the drive shaft 18 to the prime mover. In the first feed pump 19 is a working in one-quadrant operation hydraulic pump whose low-pressure side port 20 is connected via a hydraulic line 21 with the interposition of a filter 22 with a hydraulic tank 23.

The high-pressure side port 24 of the first feed pump 19 is connected with respect to a pressure limiting with a pressure relief valve 25 via a hydraulic line 26. One of the two control terminals of the pressure limiting valve 25 is connected to the hydraulic line 26. At the other control input of the pressure relief valve 25 can be adjusted via a spring 27, a certain upper pressure limit. If the pressure in the hydraulic line 26 exceeds the upper pressure limit value set by the spring 27, then the pressure limiting valve 25 opens and connects the hydraulic line 26 to the hydraulic tank 28. The pressure in the hydraulic line 26 then decreases until a pressure in the hydraulic line 26 is reached adjusts the upper pressure limit corresponding pressure and the pressure relief valve 25 goes back to the locked state.

The high-pressure side port 24 of the first feed pump 19 is connected via the hydraulic line 26 to a first check valve 29 and a second check valve 30. The first check valve 29 is connected at its second terminal to the first hydraulic load line 13, while the check valve 30 is connected at its second terminal to the second hydraulic load line 16. If the pressure in the first hydraulic load line 13 drops below that in the hydraulic line 26 via the pressure relief valve 25 set pressure level, so opens the check valve 29 and adjusts the pressure in the first hydraulic load line 13 to the pressure prevailing in the hydraulic line 26 pressure. Analogously opens at a pressure drop in the second hydraulic load line 16 under the pressure prevailing in the hydraulic line 26 pressure level, the check valve 30 and adjusts the pressure in the second hydraulic load line 16 to the pressure prevailing in the hydraulic line 26 pressure.

Parallel to the check valve 29, a pressure relief valve 31 is connected. This pressure limiting valve 31 compares the pressure value applied to one of its control inputs in the first hydraulic load line 13 with the pressure setpoint set at the other control input via a spring 32 and opens when the pressure in the first hydraulic load line 13 exceeds the set pressure value set by the spring 32. The pressure in the first hydraulic load line 13 is thereby reduced via the pressure relief valve 31 in the hydraulic line 26 until the pressure in the first hydraulic load line 13 corresponds to the pressure setpoint set by the spring 32 on the pressure relief valve 31 and the pressure relief valve 31 again in the locked state passes.

Analogously, a second pressure limiting valve 33 is connected in parallel to the check valve 30. This compares the prevailing pressure in the second hydraulic load line 16, which is guided at one of its control inputs, with a set by a spring 34 at its other control input pressure setpoint and opens when exceeding the pressure in the second hydraulic load line 16 via the spring 34th set pressure setpoint. The pressure in the second hydraulic load line 16 is reduced as long as the second pressure relief valve 33 in the hydraulic line 26 until the pressure in the second hydraulic load line 16 corresponds to the setpoint pressure set by the spring 34 and the pressure relief valve 33 again goes into the locked state.

The control of the adjustable first hydraulic pump 15 via a first adjusting device 35, the adjusting piston 36 with the swash plate (not shown in Fig. 1) of the hydraulic pump 15 is mechanically connected. The adjusting piston 36 divides the first adjusting device 35 into a first actuating pressure chamber 37 and into a second actuating pressure chamber 38. The first actuating pressure chamber 37 is connected via a hydraulic line 39 to the first output 40 of a control valve 41, which is designed as a 4/3-way valve. The second control pressure chamber 38 is connected via a hydraulic line 42 to the second output 43 of the control valve 41. The first input 44 of the control valve 41 is connected via a hydraulic line 45 and the hydraulic line 26 to the high pressure side port 24 of the feed pump 19. The second input 46 is connected via a hydraulic line 47 to a hydraulic tank 48.

The control of the control valve 41 via a first control input 49 and a second control input 50, which are both designed as electrical actuating magnets. Via an electrical line 51, the electric actuating magnet of the first control input 49 is connected to a first output 51 of a converter (not shown in FIG. 1A), which controls the mechanical deflection on a steering member 52 designed as a joystick in the direction of "tilting" in the tilting mechanism 100 determined first deflection dimension converts into a corresponding first electrical signal. The electric actuating magnet of the second control input 50 is connected via an electrical line 53 to a second output 54 of the converter (not shown in FIG. 1A), which controls the mechanical deflection on the steering member 52 in the direction of "tilting out" in the first deflection dimension determined by the tilting mechanism 100 in a corresponding second electrical signal converts.

In the event that a tipping of the bucket 6 is intended by the driver, the driver on the steering member 52, a deflection in the direction "dumping" in the tilting 100 determined first deflection dimension performed. This deflection of the loading shovel 6 corresponding deflection of the steering member 52 is transformed via a converter into a second electrical signal which is supplied via the electrical line 53 to the electric actuating magnet at the second control input 50 of the first control valve 41.

The controlled electric actuating magnet at the second control input 50 leads to a deflection of the control valve 41, so that the second control pressure chamber 38 of the first adjusting device 35 via the hydraulic line 42, 45 and 26 with the high pressure side port 24 of the first feed pump 19 and the first control pressure chamber 37 of the first Adjustment device 35 is connected via the hydraulic line 39 and 47 to the hydraulic tank 48. The adjusting piston 36 of the first adjusting device 35 is then adjusted in the direction of a delivery volume at the first terminal 14 of the adjustable first hydraulic pump 15.

This delivery volume at the first port 14 of the adjustable first hydraulic pump 15 is supplied via the first hydraulic load line 13 of the piston rod side actuating pressure chamber 5 of the second blade cylinder 2 and leads to a displacement of the actuating piston 5 in the direction of the piston-side control pressure chamber 9. The higher control pressure in the first hydraulic load line 13 is supplied via the hydraulic line 11 of the piston-side actuating pressure chamber 7 of the first blade cylinder 1, so that the actuating piston 3 is displaced in the direction of the piston rod-side actuating pressure chamber 8. Both the deflection of the actuating piston 3 of the first Bucket cylinder 1 and the deflection of the actuating piston 5 of the second blade cylinder 2 lead to a Auskippbewegung the loading blade. 6

In the case of a tipping movement of the loading shovel 6 intended by the driver, the steering member 52 is deflected in the direction of "tipping over" in the first deflection dimension determined for the tipping unit 100. At the output 51, a first electrical signal is generated by the converter of the steering member 52, which is supplied via the electrical line 59 to the electric actuating magnet at the first control input 49 of the first control valve 41. The first control valve 41 is actuated by the electric actuating magnet at the first control input 49 such that the first control pressure chamber 37 of the first adjusting device 35 via the hydraulic line 39, 45 and 26 with the high pressure side port 24 of the first feed pump 19 and the second control pressure chamber 38 of the first adjustment 35 is connected via the hydraulic line 42 and 47 to the hydraulic tank 48. The adjusting piston 36 of the first adjusting device 35 is adjusted in the direction of a delivery volume or higher setting pressure at the second port 17 of the adjustable first hydraulic pump 15.

This delivery volume at the second port 17 of the adjustable first hydraulic pump 15 is guided via the second hydraulic load line 16 in the piston-side actuating pressure chamber 9 of the second blade cylinder 2 and there leads to a deflection of the actuating piston 5 in the direction of the piston rod side actuating pressure chamber 10. The higher control pressure in the second Hydraulic load line 16 is supplied via the hydraulic line 12 of the piston rod-side actuating pressure chamber 8 of the first blade cylinder 1 and there leads to a deflection of the actuating piston 3 in the direction of the piston-side actuating pressure chamber 7. The deflection of the actuating piston 3 of the first blade cylinder 1 as well of the actuating piston 5 of the second blade cylinder 2 lead to a Einkippbewegung the loading blade. 6

To avoid escape of the hydraulic fluid from the control pressure chambers 7 and 10 of the first and second blade cylinder 1 and 2 and thus inadvertent tilting of the loading blade 6 in case of failure of the adjustable first hydraulic pump 15, a switchable check valve 55 is connected in the first hydraulic load line 13. Via a converter 57 and the electrical line 56, the opener 58 of the switchable check valve 55 is connected to the converter output 54 of the steering member 52. This ensures that the check valve 55 is open when the first and second bucket cylinders 1 and 2 supplied with deflection of the steering member 52 in the direction of "tilting" in the tilting 100 certain first deflection dimension on the second hydraulic load line 16 with a hydraulic fluid flow certain control pressure is and disposed of in the context of the closed circuit via the first hydraulic load line 13 again.

FIG. 1B shows a circuit diagram of a hydraulic control and positioning system for a hoisting gear 200 of a working tool in a mobile working machine, which consists of a first lifting cylinder 61 and a second lifting cylinder 62. In the first lifting cylinder 61, a control piston 63 is slidably guided, which is mechanically coupled to the vehicle body 4. The first lifting cylinder 61 is mechanically connected to the boom 64, the angle of rotation relative to the vehicle body 4 determines the lifting height of the arranged at the other end of the bucket 6 and the direction of rotation relative to the vehicle body 4, the vertical direction of movement of the bucket 6. In the second lifting cylinder 62, the actuating piston 65 is displaceably guided, which is connected to the loading shovel 6. The second lift cylinder 62 is mechanically connected to the vehicle body 4.

The first lifting cylinder 1 has a piston-side adjusting pressure chamber 67 and a piston rod-side adjusting pressure chamber 68. The second lifting cylinder 62 likewise has a piston-side actuating pressure chamber 69 and a piston rod-side actuating pressure chamber 70. The piston-side actuating pressure chamber 67 of the first lifting cylinder 61 is connected to the piston rod-side actuating pressure chamber 69 of the second lifting cylinder 62 via a hydraulic line 71. Likewise, the piston rod side actuating pressure chamber 68 of the first lifting cylinder 61 is connected via a hydraulic line 72 to the piston-side actuating pressure chamber 70 of the second lifting cylinder 62.

The piston rod-side actuating pressure chamber 69 of the second lifting cylinder 62 and the piston-side actuating pressure chamber 67 of the first lifting cylinder 61 is connected via a third hydraulic load line 73 to the first terminal 74 of an adjustable second hydraulic pump 75. The piston-side actuating pressure chamber 70 of the second lifting cylinder 62 or the piston rod-side actuating pressure chamber 68 of the first lifting cylinder 61 is connected via a fourth hydraulic load line 76 to the second port 77 of the adjustable second hydraulic pump 75. The adjustable second hydraulic pump 75 is driven via a drive shaft 78 from a prime mover (not shown in FIG. 1B), for example a diesel engine, which corresponds to the prime mover for the drive shaft 16 of the first hydraulic pump 15.

In each case, a first actuating pressure chamber 8, 10 adjoins the associated cylinder piston 3, 5 with a pressure application area A1, which is smaller than the pressurization area A2, with which the other second actuating pressure chamber 7, 9 adjacent to the corresponding cylinder piston 3, 5. Each port 14, 17 of the hydraulic pump 15 is connected to a first actuating pressure chamber 8 or 10 with a smaller pressurizing area A1 and a second actuating pressure chamber 7 or 10 with a larger pressurizing area A2.

A second feed pump 79 is also driven via the drive shaft 78 to the prime mover. The second feed pump 79 is a one-quadrant operating hydraulic pump whose low-pressure side port 80 is connected via a hydraulic line 81 with the interposition of a filter 82 with a hydraulic tank 83.

The high-pressure side port 84 of the second feed pump 79 is connected with respect to a pressure limiting with a pressure relief valve 85 via a hydraulic line 86. One of the two control terminals of the pressure relief valve 85 is connected to the hydraulic line 86. At the other control input of the pressure relief valve 85, a certain upper pressure limit can be set via a spring 87. If the pressure in the hydraulic line 86 exceeds the upper pressure limit set by the spring 87, then the pressure relief valve 85 opens and connects the hydraulic line 86 to the hydraulic tank 88. The pressure in the hydraulic line 86 then decreases until a pressure in the hydraulic line 86 is reached sets the upper pressure limit corresponding pressure and the pressure relief valve 85 goes back to the locked state.

The high-pressure side port 84 of the second feed pump 79 is connected via the hydraulic line 86 to a third check valve 89 and a fourth check valve 90. The third check valve 89 is connected at its second terminal to the first hydraulic load line 73, while the fourth check valve 90 is connected at its second terminal to the second hydraulic load line 76. If the pressure in the first hydraulic load line 73 drops below the pressure level defined in the hydraulic line 86 via the pressure limiting valve 85, the third check valve 89 opens and adapts the pressure in the first hydraulic Load line 73 to the pressure prevailing in the hydraulic line 86 pressure. Similarly, opens at a pressure drop in the second hydraulic load line 76 under the pressure prevailing in the hydraulic line 86 pressure level, the fourth check valve 90 and adjusts the pressure in the second hydraulic load line 76 to the pressure prevailing in the hydraulic line 86 pressure.

Parallel to the third check valve 89, a pressure limiting valve 91 is connected. This pressure limiting valve 91 compares the pressure value applied to one of its control inputs in the third hydraulic load line 73 with the pressure setpoint set at the other control input via a spring 92 and opens when the pressure in the third hydraulic load line 73 exceeds the set pressure value set by the spring 92. The pressure in the third hydraulic load line 73 is thereby reduced via the pressure limiting valve 91 in the hydraulic line 86 until the pressure in the third hydraulic load line 73 corresponds to the pressure setpoint set by the spring 92 on the pressure relief valve 91 and the pressure relief valve 91 again in the locked state passes.

Similarly, a pressure limiting valve 93 is connected in parallel to the fourth check valve 90. This compares the prevailing pressure in the fourth hydraulic load line 76, which is guided at one of its control inputs, with a set by a spring 94 at its other control input pressure setpoint and opens when exceeding the pressure in the fourth hydraulic load line 76 through the spring 94th set pressure setpoint. The pressure in the fourth hydraulic load line 76 is reduced as long as the pressure limiting valve 93 in the hydraulic line 86 until the pressure in the fourth hydraulic load line 76 corresponds to the pressure setpoint set by the spring 94 and the Pressure relief valve 93 returns to the locked state.

The control of the adjustable second hydraulic pump 75 via a second adjusting device 95, the adjusting piston 96 with the swash plate (not shown in Fig. 1) of the hydraulic pump 75 is mechanically connected. The adjusting piston 96 divides the second adjusting device 95 into a first actuating pressure chamber 97 and into a second actuating pressure chamber 98. The first actuating pressure chamber 97 is connected via a hydraulic line 99 to the first output 101 of a control valve 102, which is designed as a 4/3-way valve. The second actuating pressure chamber 98 is connected via a hydraulic line 103 to the second output 104 of the control valve 102. The first input 105 of the control valve 102 is connected via a hydraulic line 106 and the hydraulic line 86 to the high pressure side port 84 of the feed pump 79. The second input 107 is connected via a hydraulic line 108 to a hydraulic tank 109.

The control of the second control valve 102 via a first control input 110 and a second control input 111, which are both designed as electrical actuators. Via an electrical line 112, the electric actuating magnet of the first control input 110 is connected to a third output 113 of a converter (not shown in FIGS. 1A or 1B) which controls the mechanical deflection on a steering member 52 (in FIG. 1A) designed as a joystick shown) in the direction of "lifting" in which the hoist 200 determined second deflection dimension converts into a corresponding thereto third electrical signal. The electrical actuating magnet of the second control input 111 is connected via an electrical line 114 to a fourth output 115 of the converter (not shown in FIGS. 1A or 1B), which controls the mechanical deflection on the steering member 52 in the direction of "lowering" in the hoist 200 certain second deflection dimension in a to corresponding fourth electrical signal converts.

In the event that a lowering of the bucket 6 is intended by the driver, the driver on the steering member 52, a deflection in the direction "sinks" in the hoist 200 determined second deflection dimension is performed. This lowering of the loading shovel 6 corresponding deflection of the steering member 52 is transformed via a converter into a fourth electrical signal which is supplied via the electrical line 114 to the electric actuating magnet on the second control input 111 of the control valve 102.

The controlled electric actuating magnet at the second control input 111 leads to an actuation of the control valve 102, so that the first control pressure chamber 97 of the second adjusting device 95 via the hydraulic line 99 and 106 with the hydraulic tank 109 and the second control pressure chamber 98 of the second adjusting device 95 via the hydraulic line 103, 106 and 86 is connected to the high pressure side port 84 of the second feed pump 79. The adjusting piston 96 of the second adjusting device 95 is then adjusted in the direction of a delivery volume or higher setting pressure at the first port 74 of the adjustable second hydraulic pump 75.

This delivery volume at the first port 74 of the adjustable second hydraulic pump 75 is supplied via the third hydraulic load line 73 of the piston rod side actuating pressure chamber 69 of the second lifting cylinder 62 and leads to a displacement of the actuating piston 65 in the direction of the piston-side actuating pressure chamber 70. The higher control pressure in the third hydraulic load line 73 is supplied via the hydraulic line 71 of the piston-side actuating pressure chamber 67 of the first lifting cylinder 61, so that the actuating piston 63 is displaced in the direction of the piston rod-side actuating pressure chamber 68. Both the deflection of the actuating piston 63 of the first

Lifting cylinder 61 and the deflection of the actuating piston 65 of the second lifting cylinder 62 lead to a rotational movement of the boom 64 down relative to the vehicle body 4 and thus, to a lowering of the loading blade 6 relative to the vehicle body. 4

In a lifting of the loading shovel 6 intended by the driver, the steering member 52 is deflected in the direction of "lifting" in the second deflection dimension determined for the hoist 200. At the output 113 a third electrical signal is generated by the converter of the steering member 52 (shown in Fig. 1A), which is supplied via the electrical line 112 to the electric actuating magnet at the first control input 110 of the control valve 102. The control valve 102 is deflected by the electric actuating magnet at the first control input 110 such that the first control pressure chamber 97 of the second adjusting 95 via the hydraulic line 99, 106 and 86 with the high pressure side port 84 of the second feed pump 79 and the second control pressure chamber 98 of the second adjusting 95th is connected via the hydraulic line 103 and 108 to the hydraulic tank 109. The adjusting piston 96 of the second adjusting device 95 is adjusted in the direction of a delivery volume or higher setting pressure at the second port 77 of the adjustable first hydraulic pump 75.

This delivery volume or this higher setting pressure at the second port 77 of the adjustable second hydraulic pump 75 is guided via the fourth hydraulic load line 76 in the piston-side actuating pressure chamber 70 of the second lifting cylinder 62 and leads there to a deflection of the actuating piston 65 in the direction of the piston rod-side actuating pressure chamber 69th Der higher control pressure in the fourth hydraulic load line 76 is supplied via the hydraulic line 72 of the piston rod-side actuating pressure chamber 68 of the first lifting cylinder 61 and leads there to a deflection of the actuating piston 63 in the direction of the piston-side actuating pressure chamber 67th Die Auslenkung des Control piston 63 of the first lifting cylinder 61 as well as the adjusting piston 65 of the second lifting cylinder 62 lead to a rotational movement of the boom 64 upwards relative to the vehicle body 4 and thus to a lifting of the loading blade 6 relative to the vehicle body. 4

In order to prevent escape of the hydraulic fluid from the control pressure chambers 68 and 70 of the first and second lift cylinders 61 and 62 and thus inadvertent lowering of the boom 64 and thus the loading blade 6 in case of failure of the adjustable second hydraulic pump 75 is in the fourth hydraulic load line 73 a Check valve 116 connected. Via a converter 117 and an electrical line 118, the opener 129 of the switchable check valve 116 is connected to the converter output 115 of the steering member 52. This ensures that the check valve 116 is open when the first and second lift cylinders 61 and 62 supplied with deflection of the steering member 52 in the direction of "lowering" in the second displacement dimension determined by the hoist 200 on the third hydraulic load line 73 with a hydraulic fluid flow certain control pressure is and disposed of in the context of the closed circuit via the fourth hydraulic load line 76 again.

If the driver plans to plan the plane solely by the weight of the loading shovel resting on the plane - without application of a control pressure generated specifically by the working hydraulics - ("floating position" of the loading shovel 6), then a between the third and fourth hydraulic load line 73 and 76 located 2/2-way valve 119 is opened via an electrical or hydraulic control signal at the second control input 121. This electrical or hydraulic control signal is generated after closing a switch 120 by the operator intentionally planarizing the plane from an electrical transducer disposed on the switch 120 (not shown in FIG. 1B) or from a hydraulic control valve (in FIG

FIG. 1B, not shown) and supplied to the second control input 121 via the electrical or hydraulic line 122. When the switch 120 is open, the 2/2-way valve 119 is switched to the locked state by the spring 124 attached to the first control input 123, in which there is no hydraulic connection between the third and fourth hydraulic load lines 73 and 76.

Occurring pitching vibrations, in particular of the filled loading shovel 6 while the mobile working machine is moving at a higher driving speed, are damped by a hydraulic control arrangement 125. For this purpose, a signal corresponding to the traveling speed of the mobile working machine is guided by the tachogenerator 126 of the vehicle to the input 127 of the hydraulic control arrangement 125. If the vehicle speed is above a certain value and the driver opens a shut-off valve in the interior of the hydraulic control arrangement 125 via a pushbutton, the actuating pressure chambers 68 and 70 of the lifting cylinders 61 and 62 for lifting the loading bucket 6 via the hydraulic load line 73, the hydraulic line 128 and the open shut-off valve is released to a hydraulic accumulator inside the hydraulic control assembly 125. This hydraulic accumulator is charged via a pressure reducing valve in the interior of the hydraulic control arrangement 125 from the second hydraulic pump 75 to the expected load pressure in the lifting cylinders 61 and 62. A sagging of the loading shovel 6 when the hydraulic control arrangement 125 is activated for damping the pitching vibrations of the loading shovel 6 is thus minimized. More detailed details of the functional structure and the operation of the hydraulic control assembly 125 for damping pitching vibrations of the bucket 6 while driving the mobile machine can be found in DE 41 29 509 C2, the content of which is incorporated into the present application.

In contrast to the first embodiment of the hydraulic control and positioning system according to the invention for a tilting mechanism 100 in FIG. 1A and for a lifting mechanism 200 in FIG. 1B, in which electrical activation of the first and second control valves 41 and 102 is realized, in FIG. 2A and 2B show a second embodiment of the hydraulic control and positioning system according to the invention for a tilting mechanism 100 and for a lifting mechanism 200 with a hydraulic control of the first and second control valves 41 and 102. For the sake of uniformity, identical reference numerals are used in Figs. 2A and 2B for like components to Figs. 1A and 1B.

Instead of the electric actuating magnets, the first control input 49 and the second control input 50 of the first control valve 41 and the first control input 110 and the second control input 111 of the second control valve 102 each have a control pressure chamber for the hydraulic control of the first and second control valves 41 and 102. The control pressure chamber of the first control input 49 of the first control valve 41 is supplied via the hydraulic line 51 from the pressure at the first output 129 of the pilot control device 130. The control pressure chamber of the second control input 50 of the first control valve 41 is supplied via the hydraulic line 53 from the pressure at the second output 131 of the pilot control device 130. The control pressure chamber of the first control input 110 of the second control valve 102 is supplied via the hydraulic line 112 from the pressure at the third output 132 of the pilot control device 130. The control pressure chamber of the second control input 111 of the second control valve 102 is supplied via the hydraulic line 114 from the pressure at the fourth output 133 of the pilot control device 130.

The first input 134 of the pilot control device 130 is connected via a hydraulic line 135 to the high pressure side port 24 of the first feed pump 19. The second input 136 of the pilot control device 130 is via a Hydraulic line 137 is connected to a hydraulic tank 138.

Via the two pressure reducing valves 139 and 140 of a first pressure reducing valve pair 143, whose two inputs are respectively connected to the first and second input 134 and 136 of the pilot control device 130, can via a deflection of designed as a joystick steering member 52 in the first deflection dimension determined for the tilting mechanism 100 the first and second actuating pressures pending at the first and second outlets 129 and 131 are set to control the first control valve 41. For this purpose, the mechanical deflection of the steering member 52 in the first deflection dimension to one of the two control inputs of the two pressure reducing valves 139 and 140 is performed.

In the ratio of the pressure difference between the control pressure caused by the deflection of the steering member 52 in the first deflection dimension at one of the two control inputs of the pressure reducing valve 139 and the guided to the other control input of the pressure reducing valve 139 first control pressure at the first output 129 of the pilot control device 130 is by the pressure reducing valve 139th a ratio pressure between the pressures applied to the first and second inputs 134 and 136 of the pilot control device 130 is switched through to the first output 129 of the pilot control device 130.

Analogously, in the ratio of the pressure difference between the control pressure caused by the deflection of the steering member 52 in the first deflection dimension at one of the two control inputs of the pressure reducing valve 140 and the second control pressure guided to the other control input of the pressure reducing valve 140 at the second output 131 of the pilot control device 130 through the pressure reducing valve 140, a ratio pressure between the pressure applied to the first and second inputs 134 and 136 of the pilot control device 130 is switched through to the second output 131 of the pilot control device 130.

Via the two pressure reducing valves 141 and 142 of a second pressure reducing valve pair 144, whose two inputs are respectively connected to the first and second inputs 134 and 136 of the pilot control device 130, can via a deflection of designed as a joystick steering member 52 in the second displacement dimension determined for the hoist 200 the third and fourth actuating pressure pending at the third and fourth outlets 132 and 133 are set to control the second control valve 102. For this purpose, the mechanical deflection of the steering member 52 in the second deflection dimension to one of the two control inputs of the two pressure reducing valves 141 and 142 is performed.

In the ratio of the pressure difference between the control pressure caused by the deflection of the steering member 52 in the second deflection dimension at one of the two control inputs of the pressure reducing valve 141 and the third control pressure guided to the other control input of the pressure reducing valve 141 at the third output 132 of the pilot control device 130 is by the pressure reducing valve 141st a ratio pressure between the pressure applied to the first and second inputs 134 and 136 of the pilot control device 130 is switched through to the third output 132 of the pilot control device 130.

Analogously, in the ratio of the pressure difference between the control pressure caused by the deflection of the steering member 52 in the second deflection dimension at one of the two control inputs of the pressure reducing valve 142 and the fourth control pressure supplied to the other control input of the pressure reducing valve 142 at the fourth output 133 of the pilot control device 130 through the pressure reducing valve 142, a ratio pressure between the pressure applied to the first and second inputs 134 and 136 of the pilot control device 130 is switched through to the fourth output 133 of the pilot control device 130.

The operation of the adjustment of the adjustable first and second hydraulic pump 15 and 75 via the first and second adjusting means 35 and 95, which are controlled by the first and second control valve 41 and 102, and the operation of the blade and lifting cylinder assembly in the second embodiment The hydraulic control and positioning system for a tilting mechanism 100 and a lifting mechanism 200 according to the invention corresponds to the functioning of the corresponding components in the first embodiment of the hydraulic control and positioning system for a tilting mechanism 100 and for a lifting mechanism 200, so that a repeated description of this operation is omitted at this point.

A peculiarity of the embodiment shown in Figures 2A and 2B over the embodiment shown in Figures 1A and 1B is also that a Druckabschneidung 163 is present. The pressure cut 163 consists of the shuttle valve 160 and the pressure relief valve 161. The shuttle valve 160 is connected to the load lines 13 and 16 or 73 and 76 and selects the higher load pressure in the two load lines 13 and 16 or 73 and 76, respectively. This acts as a control pressure for the pressure relief valve 161. If the pressure in the higher load pressure leading load line 13 or 16 or 73 or 76 via a predeterminable by the spring 164 threshold, so opens the pressure relief valve 161 and the pressure in the hydraulic line 45 and 106 is being dismantled. As a result, the hydraulic pump 15 or 75 pivots back to a smaller delivery volume.

This function is advantageous in order to avoid a lasting response of the pressure relief valves 31, 33 or 91, 93, when the actuating pistons 3, 5 and 63, 65 run against their stop position. In this case, the load pressure would significantly increase upon reaching the stop, so that the pressure relief valves 31, 33 and 91, 93 respond and the load pressure then generating from draining heat into the tank. This is not effective because the hydraulic fluid is unnecessarily heated and the hydraulic pump 15 or 75 unnecessarily performs work. It is therefore more useful when reaching the stop position, zurückzuschwenken the hydraulic pump 15 and 75.

FIG. 3A shows a bucket cylinder hydraulic system of a third embodiment of a hydraulic control and positioning system according to the invention for a working tool in a mobile working machine in which an actuating piston 130 and 131 with a two-sided piston rod is displaceable in each of the first and second bucket cylinders 1 and 2.

The adjusting piston 130 is movably guided with its piston-side piston rod through a recess 138 in the first bucket cylinder 1 and in the loading shovel 138 with its body-side piston rod through a recess 139 in the first bucket cylinder 1 and with its body-side end mechanically connected to the body 4.

The actuating piston 131 is movably guided with its charge-side piston rod through a recess 140 in the second bucket cylinder 2, mechanically connected at its bucket end with the bucket 6 and movably guided with its body-side piston rod through a recess 141 of the second bucket cylinder 2.

The length of the bucket-side piston rod of the actuating piston 130 is dimensioned so that the actuating piston 130 is in contact with the recess 138 at any desired actuating pressure level in the first hydraulic load line 13. Analogously, the length of the body-side piston rod of the actuating piston 131 is dimensioned such that the actuating piston 131 is in contact with the recess 141 at any desired actuating pressure level in the second hydraulic load line 16.

The first bucket cylinder 1 is mechanically connected at its loading bucket end with the loading bucket 6. The second bucket cylinder 2 is mechanically connected with its body-side end with the body 4 so that the actuator piston 131 does not come into contact with the body 4 at any deflection in the second bucket cylinder 2.

The displaceable actuating piston 130 separates the first bucket cylinder 1 into a loading-bucket-side positioning chamber 132 and a body-side actuating pressure chamber 133. Analogously, the displaceable actuating piston 131 separates the second bucket cylinder 2 into a loading-bucket-side positioning chamber 134 and a body-side actuating pressure chamber 135. The two charge-bucket-side positioning pressure chambers 132 and 134 are over a hydraulic line 136, the body-side actuating pressure chambers 133 and 135 connected to each other via a hydraulic line 137. The two charging blade-side actuating pressure chambers 132 and 134 are connected via the first hydraulic load line 13 to the first terminal 14 of the first hydraulic pump 15. The two body-side control pressure chambers 133 and 135 are connected via the second hydraulic load line 16 to the second port 17 of the first hydraulic pump 15.

The operation of the further embodiment of the bucket cylinder hydraulic in Fig. 3A corresponds to the operation of the first embodiment of the bucket cylinder hydraulic in Fig. 1A, so that a detailed description thereof can be omitted. The bucket cylinder hydraulic in Fig. 3A differs from the bucket cylinder hydraulic in Fig. 1A solely in the possibility of paralleling the bucket cylinders 1 and 2 due to equal expansion and compression volumes in the two setting pressure chambers 132 and 133, 134 and 135, respectively.

In Fig. 3B is a Hubzylinderhydraulik shown in a third embodiment of a hydraulic control and positioning system according to the invention for a working tool in a mobile machine in which in the first and second lift cylinders 61 and 62 each have a control piston 142 and 143 is displaceable with a two-sided piston rod.

The adjusting piston 142 is movably guided with its boom-side piston rod through a recess 148 in the first lifting cylinder 61 and in the arm 64, with its body-side piston rod through a recess 149 in the first lifting cylinder 61 and with its body-side end mechanically connected to the body 4.

The actuating piston 143 is movably guided according to an alternative embodiment with its boom side piston rod through a recess 150 in the second lifting cylinder 62, mechanically connected at its jib end with the boom 64 and movably guided with its body-side piston rod through a recess 151 of the second lifting cylinder 62.

The length of the bucket-side piston rod of the actuating piston 142 is dimensioned so that the actuating piston 142 is in contact with the recess 148 at any desired actuating pressure level in the third hydraulic load line 73. Analogously, the length of the body-side piston rod of the actuating piston 143 is dimensioned such that the actuating piston 143 is in contact with the recess 151 at any desired actuating pressure level in the fourth hydraulic load line 76. The length of the recess 151 in the fourth lifting cylinder 62 is dimensioned such that the actuating piston 143 does not come into contact with the body 4 at any desired pressure ratios in the third and fourth hydraulic load lines 73 and 76.

The first lift cylinder 61 is mechanically connected at its boom-side end to the boom 64. The second lifting cylinder 62 is mechanically connected with its body-side end to the body 4 so that the adjusting piston 143 does not come into contact with the body 4 at any deflection in the second lifting cylinder 62.

The displaceable actuating piston 142 separates the first lifting cylinder 61 into a boom-side adjusting chamber 144 and a body-side actuating pressure chamber 145. Analogously, the displaceable actuating piston 143 separates the second lifting cylinder 62 into a boom-side actuating pressure chamber 146 and a body-side actuating pressure chamber 147. The two boom-side actuating pressure chambers 144 and 146 are over a hydraulic line 151, the body-side adjusting pressure chambers 145 and 147 via a hydraulic line 152 connected to each other. The two boom-side control pressure chambers 145 and 146 are connected via the third hydraulic load line 73 to the first port 74 of the second hydraulic pump 75. The two body-side control pressure chambers 145 and 146 are connected via the fourth hydraulic load line 76 to the second port 77 of the second hydraulic pump 75.

The operation of the other embodiment of the lifting cylinder hydraulic in Fig. 3B corresponds to the operation of the first embodiment of the lifting cylinder hydraulic in Fig. 1B, so that a detailed description thereof is omitted. The lift cylinder hydraulic in Fig. 3B differs from the lift cylinder hydraulic in Fig. 1B only in the possibility of parallel connection of the lift cylinders 61 and 62 due to equal expansion and compression volumes in the two set pressure chambers 144 and 145 and 146 and 147.

Claims (23)

1. Lifting mechanism (100) for a mobile machine, with a hydraulic control and adjustment system and a working tool (6), with at least a first and second lifting cylinder (61, 62), in which cylinder pistons (63, 65) are displaceable, the position or direction of movement of which in the lifting cylinders (61, 62) fix the lifting height or the vertical direction of movement of the working tool (6) relative to a vehicle body (4) of the mobile machine, wherein each of the cylinder pistons (63, 65) divides the associated lifting cylinder (61, 62) into two adjusting pressure chambers (67 and 68, 69 and 70) in each case and with a first hydraulic pump (75), adjustable in respect of the discharge volume, the first connection (74) of which is connected depending on the vertical direction of movement of the working tool (6) to one of the adjusting pressure chambers (67) of the first lifting cylinder (61) and one of the adjusting pressure chambers (69) of the second lifting cylinder (62) and the second connection (77) of which is connected in a closed circuit to the other adjusting pressure chamber (68) of the first lifting cylinder (61) and the other adjusting pressure chamber (70) of the second lifting cylinder (62),
   characterised in that
   a piston side adjusting pressure chamber (67) of the first lifting cylinder (61) is connected to a piston rod side adjusting pressure chamber (69) of the second lifting cylinder (62) via a first hydraulic line (71) and a piston rod side adjusting pressure chamber (68) of the first lifting cylinder (61) is connected to a piston side adjusting pressure chamber (70) of the second lifting cylinder (62) via a second hydraulic line (72) and the first lifting cylinder (61) and the adjusting piston (65, 143) of the second lifting cylinder (62) are connected to a boom (64) connecting the working tool (6) to the vehicle body (4) of the mobile machine and the second lifting cylinder (62) and the adjusting piston (63, 142) of the first lifting cylinder (61) can be connected to the body (4) of the mobile machine.
2. Lifting mechanism according to claim 1,
   characterised in that
   in each case a first adjusting pressure chamber (68; 69) borders on the associated cylinder piston (63; 65) with a pressurisation face (A1) which is smaller than the pressurisation face (A2) with which the other second adjusting pressure chamber (67; 70) in each case borders on the corresponding cylinder piston (63; 65) and in that each connection (74; 77) of the hydraulic pump (75) is connected to a first adjusting pressure chamber (68; 69) with a smaller pressurisation face (A1) and a second adjusting pressure chamber (70; 67) with a larger pressurisation face (A2).
3. Lifting mechanism according to claim 1 or 2,
   characterised in that
   the two boom side adjusting pressure chambers (144, 146) of the first and second lifting cylinders (61, 62) are connected via a first hydraulic line (151) and the two vehicle body side adjusting pressure chambers (145, 147) of the first and second lifting cylinders (61, 62) via a second hydraulic line (152).
4. Tilting mechanism (200) for a mobile machine, with a hydraulic control and adjustment system and with a loading shovel (6) serving as a working tool (6), with at least a first and second shovelling cylinder (1, 2), in which cylinder pistons (3, 5) are displaceable, the position or direction of movement of which in the shovelling cylinders (1, 2) fix the tilting angle or the tilting direction of the loading shovel (6) relative to a vehicle body (4), wherein each of the cylinder pistons (3, 5) divides the associated shovelling cylinder (1, 2) into two adjusting pressure chambers (7 and 8, 9 and 10) in each case, and with a hydraulic pump (15), adjustable in respect of the discharge volume, the first connection (14) of which is connected depending on the tilting direction of the loading shovel (6) to one of the adjusting pressure chambers (7) of the first shovelling cylinder (1) and one of the adjusting pressure chambers (10) of the second shovelling cylinder (2) and the second connection (17) of which is connected in a closed circuit to the other adjusting pressure chamber (8) of the first shovelling cylinder (1) and the other adjusting pressure chamber (9) of the second shovelling cylinder (2),
   characterised in that
   the piston side adjusting pressure chamber (7) of the first shovelling cylinder (1) is connected to the piston rod side adjusting pressure chamber (10) of the second shovelling cylinder (2) via a first hydraulic line (11) and the piston rod side adjusting pressure chamber (8) of the first shovelling cylinder (1) is connected to the piston side adjusting pressure chamber (9) of the second shovelling cylinder (2) via a second hydraulic line (12) and the first shovelling cylinder (1) and the adjusting piston (5, 131) of the second shovelling cylinder (2) are connected to the loading shovel (6) and the second shovelling cylinder (2) and the adjusting piston (3, 130) of the first shovelling cylinder (1) can be connected to the body (4) of the mobile machine.
5. Tilting mechanism according to claim 4,
   characterised in that
   in each case a first adjusting pressure chamber (8; 10) borders on the associated cylinder piston (3; 5) with a pressurisation face (A1) which is smaller than the pressurisation face (A2) with which the other second adjusting pressure chamber (7; 9) in each case borders on the corresponding cylinder piston (3; 5) and in that each connection (14; 17) of the hydraulic pump (15) is connected to a first adjusting pressure chamber (10; 8) with a smaller pressurisation face (A1) and a second adjusting pressure chamber (9; 7) with a larger pressurisation face (A2).
6. Tilting mechanism according to claim 4 or 5,
   characterised in that
   the two loading shovel side adjusting pressure chambers (132, 134) of the first and second shovelling cylinders (1, 2) are connected via a first hydraulic line (136) and the two vehicle body side adjusting pressure chambers (133, 135) of the first and second shovelling cylinders (1, 2) via a second hydraulic line (137).
7. Lifting and tilting mechanism according to claim 1 and 4,
   characterised in that
   the discharge direction of the first hydraulic pump (75) operating in two-quadrant operation fixes the vertical direction of movement of the working
   tool (6) or the discharge direction of the second hydraulic pump (15), likewise operating in two-quadrant operation, fixes the tilting direction of the loading shovel (6).
8. Lifting and tilting mechanism according to claim 1 and 4,
   characterised in that
   the discharge volume discharged at the first and second connections (74, 77) of the first hydraulic pump (75) fixes the lifting height of the working tool (6) or the discharge volume discharged at the first and second connection (14, 17) of the second hydraulic pump (15) fixes the tilting angle of the loading shovel (6).
9. Lifting and tilting mechanism according to claim 8,
   characterised in that
   the adjustment of the discharging device of the second hydraulic pump (15) and the discharge volume discharged at the first and second connections (14, 17) of the second hydraulic pump (15) is done as a function of a deflection set on a steering instrument (52) constructed in the manner of a joystick in a first deflection dimension and the setting of the direction of rotation of the first hydraulic pump (75) and the adjusting pressure built up at the first and second connections (74, 77) of the first hydraulic pump (75) is done as a function of a deflection set on the steering instrument (52) constructed in the manner of a joystick in a second deflection dimension.
10. Lifting and tilting mechanism according to claim 9,
    characterised in that
    a first adjusting valve (41) is actuated as a function of the deflection of the steering instrument (52) in the first deflection dimension and a second adjusting valve (102) is actuated as a function of the deflection of the steering instrument (52) in the second deflection dimension.
11. Lifting and tilting mechanism according to claim 10,
    characterised in that
    the deflection of the first adjusting valve (41) is done by electric adjusting magnets on control connections (49, 50) of the first adjusting valve (41), wherein one control connection (49) receives a first electric signal, corresponding to the deflection of the steering instrument (52) in the direction of the first deflection dimension, corresponding to the tilting inwards movement, and the other control connection (50) receives a second electric signal, corresponding to the deflection of the steering instrument (52) in the direction of the first deflection dimension, corresponding to the tilting outwards movement, from a transformer of the steering instrument (52) and in that the deflection of the second adjusting valve (102) is done by electric adjusting magnets at control connections (110, 111) of the second adjusting valve (102), wherein one control connection (110) receives a third electric signal, corresponding to the deflection of the steering instrument (52) in the direction of the second deflection dimension, corresponding to the lifting movement, and the other control connection (111) receives a fourth electric signal, corresponding to the deflection of the steering instrument (52) in the direction of the second deflection dimension, corresponding to the lowering movement, from a transformer of the steering instrument (52).
12. Lifting and tilting mechanism according to claim 10,
    characterised in that
    the deflection of the first adjusting valve (41) is done by adjusting pressures generated by a pilot control device (130) from the deflection of the steering instrument (52) in the first deflection dimension and supplied to control chambers located at the two control connections (49, 50) of the first adjusting valve (42) and the deflection of the second adjusting valve (102) is done by adjusting pressures generated by the pilot control device (130) from the deflection of the steering instrument (52) in the second deflection dimension and supplied to control chambers located at the two control connections (110, 111) of the second adjusting valve (102).
13. Lifting and tilting mechanism according to claim 12,
    characterised in that
    via a first pair of pressure reducing valves (143) consisting of two pressure reducing valves (139, 140), the inputs of which are connected in each case to a high pressure side connection (24) of a first feed pump (19), and a hydraulic tank (138) which generates adjusting pressures corresponding to the deflection of the steering instrument (52) in the two directions of the first deflection dimension, the pilot control device (130) generates corresponding adjusting pressures for actuating the first adjusting valve (42) and via a second pair of pressure reducing valves (144), consisting of two pressure reducing valves (141, 142), the inputs of which are connected in each case to a high pressure side connection (24) of a first feed pump (19) and a first hydraulic tank (138) which generates adjusting pressures corresponding to the deflection of the steering instrument (52) in the two directions of the second deflection dimension for the second adjusting valve (102).
14. Lifting and tilting mechanism according to one of claims 10 to 13,
    characterised in that
    the first and second adjusting valve (41, 102) is in each case a 4/3 port directional control valve, wherein the first input connection (44, 105) of the first adjusting valve (41) is connected to the high pressure side connection (24) of the first feed pump (19), the first input connection (105) of the second adjusting valve (102) is connected to a high pressure side connection (84) of a second feed pump (79), the second input connection (46, 107) of the first and second adjusting valves (41, 102) is connected in each case to a hydraulic tank (48, 109), the first output connection (40) of the first adjusting valve (41) is connected to a first adjusting pressure chamber (37) of a first adjusting device (35), the first output connection (101) of the second adjusting valve (102) is connected to a first adjusting pressure chamber (97) of a second adjusting device (95), the second output connection (43) of the first adjusting valve (41) is connected to a second adjusting pressure chamber (38) of a first adjusting device (35) and the second output connection (104) of the second adjusting valve (102) is connected to a second adjusting pressure chamber (98) of a second adjusting device (95).
15. Lifting and tilting mechanism according to claim 14,
    characterised in that
    adjustment of the second hydraulic pump (15) in respect of the discharge direction and the discharge volume discharged at the first and second connection (14, 17) is done by the first adjusting device (35) and adjustment of the first hydraulic pump (75) in respect of the discharge direction and the discharge volume discharged at the first and second connections (74, 77) by the second adjusting device (95).
16. Lifting and tilting mechanism according to one of claims 13 to 15,
    characterised in that
    the second hydraulic pump (15) and the first feed pump (19) or the first hydraulic pump (75) and the second feed pump (79) are driven by a common shaft (18, 78) in each case of a common or in each case separate machine, in particular by a diesel aggregate.
17. Lifting and tilting mechanism according to one of claims 13 to 16,
    characterised in that
    a low pressure side connection (20) of the first feed pump (19) is connected via a filter (22) to a hydraulic tank (23), a low pressure side connection (80) of the second feed pump (79) via a filter (82) to a hydraulic tank (83), the high pressure side connection (24) of the first feed pump (19) via a check valve (29, 30) in each case to a first hydraulic load line (13) attached to a first connection (14) of the second hydraulic pump (15) and to a second hydraulic load line (16) attached to a second connection (17) of the second hydraulic pump (15) and the high pressure side connection (84) of the second feed pump (79) via a check valve (89, 90) in each case to a third hydraulic load line (73) attached to a first connection (74) of the first hydraulic pump (75) and to a fourth hydraulic load line (76) attached to a second connection (77) of the first hydraulic pump (75).
18. Lifting and tilting mechanism according to claim 17,
    characterised in that
    a check valve (55, 116) with an opener (58, 129) is provided in the first and third hydraulic load lines (13, 73) in each case.
19. Lifting and tilting mechanism according to claim 18,
    characterised in that,
    after transformation into a corresponding pressure, the second electric adjusting signal actuates an opener (58) of the check valve (55) integrated in the first hydraulic load line (13) and, after transformation into a corresponding pressure, the fourth electric adjusting signal actuates an opener (129) of the check valve (116) integrated in the third hydraulic load line (73).
20. Lifting and tilting mechanism according to claim 17,
    characterised in that
    the second adjusting pressure generated by the pilot control device (130) actuates an opener (58) of the check valve (55) integrated in the first hydraulic load line (13) and the fourth adjusting pressure generated by the pilot control device (130) actuates an opener (129) of the check valve (116) integrated in the third hydraulic load line (73).
21. Lifting and tilting mechanism according to claim 17,
    characterised in that
    located between the third and fourth hydraulic load lines (73, 76) is a 2/2 port directional control valve (119) which opens in the operating state "floating position" of the boom (64) by applying an electric signal to an electric adjusting magnet located at the control input (121) of the 2/2 port directional control valve (119) or alternately by applying an adjusting pressure in a control chamber located at the control input (121) of the 2/2 port directional control valve (119).
22. Lifting and tilting mechanism according to claim 17,
    characterised in that
    the third hydraulic load line (73) is connected via a hydraulic line (128) to a hydraulic control arrangement (125) to damp pitching oscillations of the working tool (6) while the mobile machine is travelling.
23. Lifting and tilting mechanism according to claim 22,
    characterised in that
    an electric signal corresponding to the speed of the mobile machine is conducted from a tachogenerator (126) of the mobile machine to the input (127) of the hydraulic control arrangement (125) to damp pitching oscillations of the working tool (6) while the mobile machine is travelling.

Images