RU2571068C2 - Valve system - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: system is intended to control the attached hoisting gear of the mobile work vehicle. The system has at least one power cylinder with piston separating the first cavity of the cylinder and its second cavity, at that the first cavity of the power cylinder by the work line is connected with the hydraulic distribution system to control the power cylinder of one-way action, having lifting module for the work line connection with the supply line, and lowering module to connect the work line with the drain line, and to the second cavity of the power cylinder the discharge line is connected, it is connected with the supply line and drain line via the valve distribution system, it has supply valve to connect the discharge line with the supply line and drain valve to connect the discharge line with the drain line, at that between the discharge line and drain line the pressure limiting valve is installed, and the supply valve is connected with the supply line by the work valve with provided throttle.

EFFECT: power saving.

9 cl, 5 dwg

Description

The present invention relates to a valve system of a hoisting mechanism of an agricultural machine according to the preamble of claim 1.

A similar valve system is described in DE 4313250 C2 and is intended for controlling a double acting power cylinder. This power cylinder has two cavities separated by its piston, each of which can be connected to the inlet and outlet lines through two hydraulic distributors of the distribution system. Due to this, the piston can be loaded with pressure from the side of both cavities of the power cylinder. The disadvantage of this solution is the very complex design associated with high hardware and technical costs for its implementation.

DE 10138389 A1 and DE 102006004423 A1 describe another valve system for controlling a double acting power cylinder. The cavities of such a cylinder, in contrast to the aforementioned prior art, can be connected to the inlet and outlet lines through a single valve. From the hardware and technical point of view, such a control valve has an extremely complex design and requires high production costs for its manufacture.

The catalog "Bosch EHR, Elektronisch-Hydraulische Hubwerksregelung für Traktoren 5/7", edition 1.1, issued in 1999 by Robert Bosch GmbH, presents on page 17 a valve system for a single-acting power cylinder. This valve system allows you to connect one cavity of the power cylinder with the inlet and outlet line through two valves. The disadvantage of such a valve system is that the piston moving in the power cylinder can be loaded with pressure only from the side of one cavity of the power cylinder.

Based on the foregoing, the present invention was based on the task of developing a valve system that would have an inexpensive and simple design and which would allow flexible control of the power cylinder.

This problem is solved using a valve system with the distinctive features presented in claim 1 of the claims.

According to the invention, the valve system according to the invention for controlling the lifting and hitching mechanism of an agricultural machine has at least one power cylinder with a piston separating the first cavity of the power cylinder from its second cavity, the first of which is connected by a working line to a distribution system for controlling a single-acting power cylinder . The distribution system has a lifting module for connecting the working line to the inlet line and a lowering module for connecting the working line to the outlet line. A pressure line is connected to the second cavity of the power cylinder, which is connected through a valve distribution system to a supply line and a discharge line.

The advantage of such a solution is that the piston of the power cylinder from the side of its first cavity is controlled by a traditional, inexpensive distribution system for controlling a single-acting power cylinder such as, for example, that is indicated in the prior art considered at the beginning of the description, and from the side of its second the cavity is carried out by a simple valve distribution system.

In one of the preferred embodiments, the valve distribution system has inlet and outlet valves, which can be made in the form of conventional two-way (hydro) valves.

In another preferred embodiment, the inlet valve has a shutter that is moved by the electromagnetic actuator in the direction of its open position and held in its closed position by the force of a pre-compressed spring. The outlet valve has a shutter, held in its open position by the force of a pre-compressed spring and loaded in the direction of its closed position by control pressure taken from the pressure line along the control line. Thus, to control the pressure in the second cavity of the power cylinder, it is only necessary to actuate the inlet valve, while there is no need to control the outlet valve. Instead of an electromagnetic actuator, the inlet valve can also be made with a manual actuator.

In yet another embodiment of the invention, the control line is connected to a discharge line by a discharge line with a throttle provided therein. This makes it possible to simply reduce the control pressure by dumping it into a discharge line in order to switch the discharge valve to its open position by spring force. The presence of a throttle allows you to load the shutter of the outlet valve with control pressure.

To avoid loading the gate of the outlet valve with the control pressure when the outlet valve is open and the inlet valve is closed, a non-return valve loaded with a pre-compressed spring is closed in the pressure line between the branch line to the outlet valve and closed by the force of the pre-compressed spring, in the direction from power cylinder.

To limit the pressure in the second cavity of the power cylinder, a pressure limiting valve is provided, located between the pressure line and the discharge line.

The inlet valve is connected to the inlet line, for example, a working channel with a throttle provided therein.

In order to ensure the possibility of supplying a working medium with a constant volume flow, regardless of pressure fluctuations in the pressure line in the working channel, a pressure differential valve is located in front of the throttle. The shutter of such a differential pressure valve in this case is loaded in the direction of its open position by the force of the spring and pressure taken in the area between the throttle and the inlet valve, and in the direction of the closed position it is loaded with pressure taken in the area between this differential pressure valve and the throttle.

In another preferred embodiment, the locking element of the pressure limiting valve is loaded in the direction of its closure by the force of a spring, which is made manually adjustable or by an electromagnetic actuator. Due to this, the maximum limited pressure in the second cavity of the power cylinder can be adjusted to any value. It can be, for example, from 10 to 30 bar.

The distribution system can be made in the form of a single block similar to the prior art discussed at the beginning of the description. In this case, it is designed to control a single-acting power cylinder in an intermediate panel or in a hydropanel, primarily in a pressure sensitive hydropanel.

Components for controlling pressure in the second cavity of the ram can be located in the intermediate panel for connection to a distribution system or can be made as separate components.

Other preferred embodiments of the invention are the subject of the dependent claims.

Below the invention is described in more detail by the example of some preferred options for its implementation with reference to the accompanying description of the schematic drawings, which show:

figure 1 - hydraulic circuit valve system made in the first embodiment,

figure 2 - hydraulic circuit valve system made in the second embodiment,

figure 3 - hydraulic circuit valve system made in the third embodiment,

figure 4 - hydraulic circuit valve system made in the fourth embodiment, and

figure 5 - hydraulic circuit valve system made in the fifth embodiment.

Figure 1 in the form of a hydraulic circuit shows a valve system 1 for controlling two power cylinders 2, 4, made according to the first embodiment. Such power cylinders 2, 4 are, for example, components of the tractor attachment system or other movable working equipment.

Each of the two power cylinders 2 and 4 has a piston 10, respectively 12, connected to the corresponding rod 6, respectively 8. Each of the pistons 10 and 12 thus separates its first, or piston, cavity 14, respectively 16, from its power cylinder its second, or rod, cavity, respectively, of the annular cavity 18, respectively 20. Piston cavities 14, 16, on the one hand, and rod cavities 18, 20, on the other hand, are hydraulically interconnected via a connecting line 22, respectively 24.

The piston cavities 14, 16 of the power cylinders 2, 4 are made of a connected (hydro) distribution, or control, system 26 with a discharge line leading from the pump or with a drain line 28, 30 leading to the tank. The distribution system 26 is made in an intermediate panel 31 or a hydraulic panel, by which, in a preferred embodiment, is meant a load sensing, or load-controlled, hydropanel. Distribution system 26 is designed to control a single-acting power cylinder and for many years it has been used in the form of an electro-hydraulic control system (EGSR) of a lifting-mounted mechanism for tractors.

In the embodiment shown in FIG. 1, the distribution system 26 serves to “hold” the attachment in a certain position, with the tractor lifting and hitching mechanism 32, especially its rear lifting and hitching mechanism, and accordingly, under certain conditions, the mounted hinged mechanism equipment 34 either rises from the ground 35, or is kept in contact with it with a certain reference force. The need for this may arise, for example, when plowing the soil or during its cultivation.

The rod cavities 18 and 20 of the actuators 2, 4, respectively, are also made connected by a valve distribution system 36 with a discharge or a drain line 28, 30. The valve distribution system 36 is made in this case in the intermediate panel 38.

Pistons 10 and 12 of the actuators 2, 4, respectively, due to their connection to each other by connecting lines 22, 24 are moved mainly simultaneously and according to figure 1 are at the same level, respectively, at the same height. The rods 6, 8, as shown schematically in FIG. 1, are interconnected by a cross member 40, on which is located a rod 42 parallel to the rods 6, 8 for raising and lowering the lever 46, pivotally mounted on the axis 44. This lever, in turn, rises and attachment drops 34.

Distribution system 26 has a continuously adjustable 3/2-way distributor (three-way two-way distributor) 48 designed as a lifting module 48 for lifting attachments 34 and a constantly adjusted 2/2-way distributor (two-way two-way distributor) 50 made in the form of a lifting module 50. Upstream in front of the distributor 48 is an individual differential pressure valve 52. This valve is connected through a discharge connection P to a supply line 56, which is connected to a discharge line 28. Through a working connection A, an individual differential pressure valve 52 is connected to a connection line 58, which is connected to a discharge connection P of a distributor 48. The individual pressure difference valve further has a drain connection T, to which a discharge line 60 connected to the drain line 30 is connected, and a working connection A, which is connected to the connection line 62 connected to the connecting line 22 by the working line 64 and thereby with the piston cavities 14 and 16 of the actuators 2, respectively 4.

In the connecting line 62 there is a check valve 66 loaded by the force of a pre-compressed spring, which opens upstream in the direction of the piston cavities 14, 16 of the power cylinders.

The shutter of the individual differential pressure valve 52 is held in a throttled open position a by the force of a pre-compressed spring 68. The shutter of the individual differential pressure valve through the first control line 70 is pressurized between the working connection A of this individual differential pressure valve 52 and the pressure connection P of the distributor 48 in the direction of its closed position b, and through the second control line 72, along which the pressure is taken between the working connection A the distributor 48 and the check valve 66, is loaded in the direction of its open position a. The second control line 72 is additionally connected to the load pressure feedback (power feedback) channel 74, which is connected via a shuttle (or changeover) valve 76 to the load pressure feedback line 78, along which line 78 is the load pressure in the piston cavities 14 and 16 power cylinders 2, respectively 4, when it is maximum, is transmitted to an adjustable pump, which is based on this is regulated so that the pressure created by this pump prevails in the discharge line 28, exceeding load pressure by a predetermined value the pressure difference that is not shown in Figure 1. An individual differential pressure valve 52 allows the volumetric flow rate through the distributor 48 to be kept substantially constant regardless of the load.

The valve of the distributor 48 is held by the force of the pre-compressed spring 80 in its initial (or main) position x, in which the working connection A is connected to the drain connection T. The valve of the distributor 48 can be moved by the electromagnetic actuator 82 in the direction of its open position y, in which the discharge connection P connected to the working connection A, and the piston cavities 14 and 16 of the power cylinders 2, respectively 4, are hydraulically connected thereby to the discharge line 28.

To connect the piston cavities 14 and 16 of the actuators 2, 4, respectively, with the drain line 30, a distributor 50 is provided. It has a working connection A connected to the working line 64 and a drain connection connected to the discharge line 60. The valve of the distributor 50 is held by a pre-compressed spring 84 in its generally sealed closed position m and can be moved by electromagnetic actuator 86 in the direction of its open position i, in which the working connection A is connected to the drain connected T em and the piston cavities 14, 16 thereby fluidly connected to the return line 30.

To limit the pressure in the piston cavities 14 and 16, a pressure limiting valve 88 is located between the working line 64 and the discharge line 60.

The valve distribution system 36 has an inlet valve 90 for connecting the rod cavities 18 and 20 of the actuators 2, 4, respectively, with a discharge line 28 and an outlet valve 92 for connecting the rod cavities 18 and 20 with a drain line 30.

The inlet valve is made in the form of a 2/2-way valve with a pressure connection P and a working connection A. Pressure connection P is connected to a pressure line 28 by a working channel 93, and a working connection A is connected by a pressure line 94 to a connecting line 24 and thereby to the stock cavities 18 , 20. The shutter of the inlet valve 90 is held in its closed position g by the force of a pre-compressed spring 96 and can be translated by its electromagnetic actuator 98 into its open position f, in which the discharge connection nenie P is connected to the working attachment A.

The outlet valve 92 is also made, as the inlet valve 90, in the form of a 2/2-way valve and has a drain connection T, which is connected to a drain line 30 by a drain channel 100, and a working connection A, which is hydraulically connected by an intermediate line 102 to the pressure line 94 The shutter of the outlet valve 92 is held in its open position j by the force of the pre-compressed spring 104 and can be loaded through the control line 106 connected to the pressure line 94 with the pressure prevailing in it and thus transferred to its closed floor living h. The control line 106 of the discharge line 108 with a choke 110 provided therein is connected to a drain channel 100.

In the pressure line 94 between the branch point of the control line 106 and the branch point of the intermediate line 102, a check valve 112 loaded with a pre-compressed spring is opened, which opens along the flow of the working medium in the direction of the rod cavities 18 and 20. To dampen oscillations in the volumetric flow rate of the working medium in the working channel 93 throttle 114 is provided.

To limit the pressure in the pressure line 94 and thereby in the rod cavities 18 and 20 of the power cylinders 2, respectively 4, a pressure limiting valve 116 is provided located between the pressure line 94 and the drain channel 100. Such a pressure limiting valve 116 is connected to the pressure line 94 between the branch point of the intermediate line 102 to the outlet valve 92 and the connecting line 24.

The principle of operation of the valve system 1 shown in FIG. 1 is explained below.

To lift the attachment 34 or to hold it in a certain position, the pistons 10 and 12 of the power cylinders 2, respectively 4 are loaded with pressure by creating it in the piston cavities 14, respectively 16. To this end, the distributor 50 (lowering module) is de-energized and is in its closed position m, and the distributor 48 (lifting module) is energized and is in its open position y, as a result of which the piston cavities 14 and 16, through the discharge line 28, the inlet line 56, the individual differential pressure valve 52, will distribute l 48, check valve 66, working line 64 and connecting line 22 loaded with the pressure created by the pump. In addition, the pressure in the rod cavities 18 and 20 of the actuators 2, 4, respectively, is released through the valve distribution system 36. For this, the inlet valve 90 is de-energized and is in its closed position g, and the outlet valve 92 is in its open position j, in which it is held by a pre-compressed spring, as a result of which the rod cavities 18 and 20 through the connecting line 24, the pressure line 94, intermediate line 102 and a drain channel 100 are connected to a drain line 30.

To lower the lifting-and-hitching mechanism 32 from the piston cavities 14 and 16 of the power cylinders 2, respectively 4, the pressure is released into the drain line 30, as a result of which the lifting-and-hitching mechanism 32 is lowered to the ground 35 either by its own weight or by force this pressure by loading the pistons 10 and 12 with the pressure created by the pump in the rod cavities 18, respectively 20.

To lower the lifting-and-hitching mechanism 32 due to its own weight, the distributor 50 of the distribution system 26 is energized and is in its open position i, and the distributor 48 is in its initial position x. In this case, the pressure from the piston cavities 14 and 16 is released through the connecting line 22, the working line 64, the distributor 50 and the discharge line 60 into the drain line 30. The lowering speed of the pistons 10, 12 depends on the passage section of the distributor 50 in its open position i. In addition, the pressure from the rod cavities 18 and 20 is released, as described above, through the outlet valve 92 into the drain line 30, as a result of which the pistons 10 and 12 through the rod 42, cross member 40 and rods 6, respectively 8 are loaded with their own weight of the lift-mounted mechanism 32 and fall in the direction of the decreasing piston cavity 14, respectively 16.

In the operation of the valve system 1, for example, at low temperatures, it may be necessary to enable the lowering of the lifting-and-hitching mechanism 32, in spite of the increased viscosity of the working medium, by creating a pressure that promotes this. To this end, the pistons 10 and 12 are loaded with the pressure generated from the discharge line 28 created in the rod cavities 18 and 20, respectively. The pressure in the piston cavities 14 and 16, as well as when lowering the lifting-mounted mechanism by its own weight, is discharged into the drain line 30. To create pressure in the rod cavities 18 and 20, the inlet valve 90 of the valve distribution system 36 is energized and thereby switches to its open position f, as a result of which the pressure line 94 is hydraulically connected to the discharge line 28, and the shutter of the outlet valve 92 is loaded by the pressure created by the pump through the control line 106 branching off from the pressure line 94 and switched to its closed position h. The rod cavities 18 and 20 in this case through the connecting line 24, the pressure line 94, the check valve 112, the inlet valve 90 and the working channel 93 are hydraulically connected to the discharge line 28. Thus, by loading the pistons 10 and 12 with the pressure created in the rod cavities 18 20, respectively, it is possible to lower the lifting and hitching mechanism 32 under the action of the pressure contributing to this, in addition to lowering it under the action of its own weight.

The pressure in the rod cavities 18 and 20 when lowering the lifting-and-mounted mechanism under the action of the pressure contributing to this is limited by the pressure limiting valve 116. Such a pressure limiting valve 116 when, for example, due to unevenness of the earth 35, the lifting and hitching mechanism 32 is loaded through the attachment 34 by a force acting in the opposite direction to its lowering and increasing the pressure in the rod cavities 18 and 20, avoids damage due to too high pressure. The operating pressure, which is limited by the valve 116, respectively, to which it is configured, is, for example, from 10 to 25 bar.

To complete the lowering process of the lifting and hitching mechanism 32 under the action of the pressure contributing to this, for example, at the moment when the attachment 34 has reached the ground 35 or plunged into it, the hydraulic system between the piston cavities 14 and 16 of the power cylinders 2 is closed by the distribution system 26, respectively 4 and the drain line 30. Such hydraulic disconnection of the piston cavities from the drain line is provided by de-energized distributors 50 and 48, the first 50 of which in this case is in its m the closed position m, and the second 48 is in its initial position x, whereby the connection to the return line 30 through the valve 50 and the check valve 66 is blocked. However, when the pressure in the piston cavities 14 and 16 rises to a level exceeding a certain predetermined pressure, a pressure limiting valve 88 is actuated, opening a hydraulic connection to the drain line 30.

After the hydraulic connection is closed between the piston cavities 14 and 16 and the drain line 30, the rod cavities 18 and 20 release pressure into the drain line 30 through the valve distribution system 36. In this case, the inlet valve 90 is de-energized and is in its closed position g, in which it is held by a pre-compressed spring, as a result of which the pressure from the control line 106 is released through the discharge line 108 to the drain line 30, the non-return valve 112 is closed, and the outlet valve 92 is spring 104 switches to its open position j.

Distribution system 26, which is made in the form of a hydraulic panel or an intermediate panel, and valve distribution system 36, which is also made in the form of an intermediate panel 38, have the same hole pattern (connection layout) and thereby form a common drain line 30, discharge line 28 and pressure feedback line 78. The hole pattern corresponds, for example, to that of the load-sensitive hydraulic panel model SB 23, manufactured by Robert Bosch GmbH. The width of the intermediate panel 38 is preferably 40 mm.

The control of the intake valve 90 for lowering the lifting-and-hitching mechanism under the action of the pressure contributing to this is carried out by the operator through the corresponding control element of the EGSR system or without the participation of the operator by means of a probe registering the lowering of the lifting-and-hinged mechanism 32.

The valve system 1 discussed above can be used, for example, in a front hoist and / or rear hoist.

Figure 2 shows the hydraulic circuit of the valve system 1, made in the second embodiment. In contrast to the first embodiment shown in FIG. 1, the components of the valve distribution system 36 are not made in the intermediate panel 38, but as separate components. In this case, the drain channel 100 is connected to the drain connection T, and the working channel 93 is connected to the discharge connection P of the distribution system 26.

Figure 3 shows the hydraulic circuit of the valve system 1, made according to the third embodiment. In this case, the valve distribution system 36 is made in the intermediate panel 38 and additionally has a pressure difference valve 120 to maintain a constant regulated volumetric flow rate of the working medium regardless of fluctuations in the pressure created by the pump in the discharge line 28. The pressure difference valve 120 is located in the working channel 93 the flow in front of the throttle 114. Such a throttle 114 serves as a measuring diaphragm, in accordance with which under the valve 120 of the pressure difference is meant upstream differential pressure valve 120. It has a shutter which, by the force of the pre-compressed spring 122, is held in its open position k and is additionally loaded in the direction of its closed position 1, supplied via the pressure control line 124 in the working channel 93, prevailing along the flow after the throttle 114, and also fed along the line 126 control the pressure prevailing along the flow in front of the throttle 114 in the area between it and the valve 120 of the pressure difference. The open positions to the shutter in the differential pressure valve 120 are throttled.

Through the valve 120 of the pressure difference, the rod cavities 18 and 20 of the power cylinders 2, 4, respectively, are supplied with a working medium with a constant volume flow rate, which makes it possible to lower the attachments 34, respectively, of the lifting and hitching mechanism 32 at a constant speed.

Figure 4 shows the hydraulic circuit of the valve system 1 made in the fourth embodiment. In this case, the pressure limiting valve 116 provided in the valve distribution system 36, in contrast to the first embodiment shown in FIG. 1, is made with an adjustable spring 128. By the pressure limiting valve 116 is meant, for example, a seat valve with a locking element (gate) that interacts with his saddle. In this case, such a locking element in the direction of its opening is loaded with pressure in the pressure line 94, and in the direction of its closing is loaded with the force of the spring 128. Adjustability of the spring 128 allows you to adjust the value of the limited pressure in the pressure line 94, respectively, in the rod cavities 18 and 20 of the power cylinders 2 , respectively 4. The higher the force of the spring 128, the higher the value of the limited pressure, i.e. the pressure required to open the pressure limiting valve 116. The limits of the force control of the spring 128 are preferably selected such that the pressure to be limited is from 10 to 30 bar.

Figure 5 shows the hydraulic circuit of the valve system 1, made according to the fifth embodiment. This embodiment differs from the fourth embodiment shown in FIG. 4 in that the pressure limiting valve 116 provided in the valve distribution system 36 does not have a manually adjustable spring 128, but a spring 128 regulated by the electromagnetic actuator 130. Due to this, the operator, primarily the tractor operator, can when operating attachments 34 in a simple way to adjust the limited pressure in the rod cavities 18 and 20 of the power cylinders 2, respectively 4.

In the case when the so-called installation of the tractor on the goats is not provided, i.e. lowering the front and rear lifting and hitching mechanisms until the tractor wheels lift off the ground, there is no need for a pressure limiting valve 116 with an airtight seat.

If necessary, to ensure the possibility of installing the tractor on the goats, various safety requirements are imposed on the valve system 1. So, for example, in the connecting line 132, branching off the pressure line 94 and connected to the pressure limiting valve 116, a ball valve is provided upstream of this valve 116.

The present invention thus provides a valve system for controlling a hoist mechanism of an agricultural machine having at least one power cylinder. It has two cavities separated by its piston. The first cylinder cavity is connected by the first working line to the EGSR system (electro-hydraulic regulation system of the lifting-mounted mechanism for tractors), which has long been known from the prior art. EGSR-system provides the possibility of loading the piston of the cylinder with pressure by creating it in the first cavity of the cylinder and relieving the pressure applied to the piston by dumping it from the first cavity of the cylinder, which makes it possible to control the lifting-mounted mechanism. In addition to this, primarily for lowering the lifting-and-hinged mechanism under the action of the pressure contributing to this, it is possible to create pressure in the second cavity of the cylinder through the valve distribution system 36.

Claims (9)

1. Valve system for controlling the lifting-and-hitching mechanism (32) of a movable working machine, which has at least one power cylinder (2, 4) with a piston (10, 12) separating the first cavity (14, 16) of the power cylinder from its second cavity (18, 20), while the first cavity (14, 16) of the power cylinder with a working line (64) is connected to a hydraulic distribution system (26) for controlling a single-acting power cylinder having a lifting module (48) for connecting the working line (64) ) with a supply line (56) and a lowering module (50) for connecting the working the first line (64) with a discharge line (60), and a pressure line (94) connected to the supply line (56) and the discharge line (60) through the valve distribution system (36) is connected to the second cavity (18, 20) of the power cylinder which has a supply valve (90) for connecting the pressure line (94) to the supply line (56) and a discharge valve (92) for connecting the pressure line (94) to the discharge line (60), characterized in that between the pressure line (94) ) and a pressure limiting valve (116) is located in the discharge line (60), and the inlet valve (90) is connected to the inlet line (56) ) the working channel (93) with the throttle (114) provided in it. 2. The valve system according to claim 1, wherein in the working channel (93) upstream of the throttle (114) there is a pressure difference valve (120), the shutter of which is loaded in the direction of its open position by the force of the spring (122) and the pressure taken in the area between the throttle (114) and the inlet valve (90), and in the direction of the closed position it is loaded with pressure taken in the area between this differential pressure valve (120) and the throttle (114). 3. The valve system according to claim 1 or 2, in which the locking element of the valve (116) for pressure limitation is loaded in the direction of its closing by the force of a spring (128), which is made manually adjustable or by an electromagnetic actuator. 4. The valve system according to claim 1, in which the inlet and outlet valves (90, 92) are two-way on / off valves. 5. The valve system according to claim 4, in which the inlet valve (90) has a shutter, moved by an electromagnetic actuator (98) in the direction of its open position and held in its closed position by the force of a pre-compressed spring, and the outlet valve (92) has a shutter, held in its open position by the force of a pre-compressed spring and loaded in the direction of its closed position by control pressure taken from the pressure line (94) along the control line (106). 6. The valve system according to claim 5, wherein the control line (106) is connected to a discharge line (60) by a discharge line (108) with a throttle (110) provided therein. 7. The valve system according to claim 5 or 6, wherein in the pressure line (94) between the control line (106) branching off from it and the intermediate line (102) branching to the outlet valve (92), a non-return valve loaded by the force of a pre-compressed spring ( 112), closed along the flow of the working medium in the direction from the power cylinder (2, 4). 8. The valve system according to claim 1, in which the distribution system (26) for controlling a single-acting power cylinder is made in an intermediate panel or in a hydraulic panel, especially in a pressure sensitive hydraulic panel. 9. The valve system according to claim 1, wherein the components for controlling pressure in the second cavity (18, 20) of the power cylinder (2, 4) are located in the intermediate panel (38) for connection to the distribution system (26).

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